CA1048862A - Intermittent driving device for sewing machines - Google Patents
Intermittent driving device for sewing machinesInfo
- Publication number
- CA1048862A CA1048862A CA76249112A CA249112A CA1048862A CA 1048862 A CA1048862 A CA 1048862A CA 76249112 A CA76249112 A CA 76249112A CA 249112 A CA249112 A CA 249112A CA 1048862 A CA1048862 A CA 1048862A
- Authority
- CA
- Canada
- Prior art keywords
- wheel
- upper shaft
- shaft
- stopper
- belt wheel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000009958 sewing Methods 0.000 title claims abstract description 90
- 230000006835 compression Effects 0.000 claims description 4
- 238000007906 compression Methods 0.000 claims description 4
- 230000015572 biosynthetic process Effects 0.000 claims 6
- 230000008878 coupling Effects 0.000 claims 2
- 238000010168 coupling process Methods 0.000 claims 2
- 238000005859 coupling reaction Methods 0.000 claims 2
- 230000003405 preventing effect Effects 0.000 claims 1
- 239000000463 material Substances 0.000 description 9
- 238000004804 winding Methods 0.000 description 5
- 230000002093 peripheral effect Effects 0.000 description 3
- 230000004323 axial length Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
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- Sewing Machines And Sewing (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A device for intermittently driving a sewing machine and for stopping the same at a predetermined angular position after one complete rotation thereof each time when the foot con-troller of the sewing machine is operated. Known similar sewing machines are intermittently driven in one complete rotation each time when the machine controller is pressed. These sewing machines are, however, forcibly stopped in such a manner that the driving power of the machine motor is wholly applied to the device for stopping the machine at a predetermined angular position. These sewing machines, therefore, produce loud sounds or noises each time the sewing machine stops, resulting in ex-cessive wear of machine parts and overloading of the machine motor. The present invention overcomes these drawbacks by pro-viding a compact sewing maching which can be intermittently driven, and can be started and stopped at a predetermined angular position after one complete rotation thereof each time the foot controller is operated. The sewing machine comprises a machine housing, an upper shaft rotatably journalled in the machine housing, a belt wheel mounted on the upper shaft and rotatable relative to the upper shaft, clutch means provided between the upper shaft and the belt wheel and operable to connect and dis-connect the belt wheel to and from the upper shaft, actuating means for actuating the clutch means to operate the same to a first position for connecting the belt wheel to the upper shaft and to a second position for disconnecting the belt wheel from the upper shaft, stopper means for engaging and stopping the ac-tuating means, releasing cam means actuated to release the ac-tuating means from the stopper means and pawl means for actuating the releasing cam means to release the actuating means from the stopper means.
A device for intermittently driving a sewing machine and for stopping the same at a predetermined angular position after one complete rotation thereof each time when the foot con-troller of the sewing machine is operated. Known similar sewing machines are intermittently driven in one complete rotation each time when the machine controller is pressed. These sewing machines are, however, forcibly stopped in such a manner that the driving power of the machine motor is wholly applied to the device for stopping the machine at a predetermined angular position. These sewing machines, therefore, produce loud sounds or noises each time the sewing machine stops, resulting in ex-cessive wear of machine parts and overloading of the machine motor. The present invention overcomes these drawbacks by pro-viding a compact sewing maching which can be intermittently driven, and can be started and stopped at a predetermined angular position after one complete rotation thereof each time the foot controller is operated. The sewing machine comprises a machine housing, an upper shaft rotatably journalled in the machine housing, a belt wheel mounted on the upper shaft and rotatable relative to the upper shaft, clutch means provided between the upper shaft and the belt wheel and operable to connect and dis-connect the belt wheel to and from the upper shaft, actuating means for actuating the clutch means to operate the same to a first position for connecting the belt wheel to the upper shaft and to a second position for disconnecting the belt wheel from the upper shaft, stopper means for engaging and stopping the ac-tuating means, releasing cam means actuated to release the ac-tuating means from the stopper means and pawl means for actuating the releasing cam means to release the actuating means from the stopper means.
Description
-`~ 104886Z
This invention relates generally to an intermittent driving device for sewing machines, and more particularly, to a device for intermittently driving a sewing machine and for stop-ping the same at a predetermined angular position after one complete rotation thereof each time the foot controller of the sewing machine is operated.
A sewing machine incorporating a device according to the present invention can be used to sew basting stitches in material, whereby the sewing machine is stopped after one complete ~
10 rotation in response to pressure applied to the foot controller. ~ -The impact and/or noise occurring when the sewing machine stops is reduced, and the machine motor is protected from overloading while the sewing machine is stopped.
Heretofore, sewing machines incorporating similar devices have been used to sew basting stitches in sewn material.
However, with these conventional sewing machines, the machine operator has to use one hand to intermittently drive the sewing machine while the other hand manipulates the sewn material. The machine operator, therefore, has had difficulties in sewing basting stitches with these conventional sewing machines.
Further, it is also known to provide sewing machines which intermittently rotate automatically in a predetermined time interval. Such sewing machines have been not convenient for sewing basting stitches because the machine operator cannot control the rotation of the sewing machine at will, especially when sewing curved or other parts of the material requiring special attention. Additionally, other known sewing machines have been provided which are intermittently driven in one complete rotation each time when the machine controller is pressed. These sewing machines are, however, forcibly stopped in such a manner that the driving power of the machine motor is wholly applied to ~ .
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the device for stopping the machine at a predetermined angular position. These sewing machines, therefore, produce loud sounds or noises each time the sewing machine stops, resulting in ex-cessive wear of machine parts and overloading of the sewing machine motor and other driving parts.
So long as all the aforementioned sewing machines are sold as household sewing machines, they should be supplied at as low a price as possible. However, such sewing machines utilize electromagnetic solenoids and associated electrical circuitry for controlling the solenoids, resulting in high production costs which render the sewing machines impractical for domestic purposes.
The present invention proposes to overcome the defects and disadvantages of conventional sewing machines such as those referred to above by providing a compact sewing machine which can be intermi~tently driven. The sewing machine can be started and stopped, without any shocks or sounds, at a predetermined angular position after one complete rotation thereof each time the foot controller is operated. Further, the machine can be selectively driven at high speed, a lower speed, or in an intermittent rota-tion, and can be started or stopped without overloading the motor.
According to the present invention, there is provideda sewing machine with an intermittent driving device comprising a machine housing, an upper shaft rotatably journalled in the machine housing, a belt wheel mounted on the upper shaft and rotatable relative to the upper shaft, clutch means provided between the upper shaft and the belt wheel and operable to connect and disconnect the belt wheel to and from the upper shaft, actua-ting means for actuating the clutch means to operate the same to a first position for connecting the belt wheel to the upper shaft and to a second position for disconnecting the belt wheel from the upper shaft, stopper means for engaging and stopping the 1~48862 actuating means, releasing means actuated to release the actuating means from the stopper means and means for actuating the releasing means to release the actuating means from the stopper means.
The releasing means suitably comprises a releasing cam means; and the means for actuating such releasing cam means to release the actuating means from the stopper means suitably compri~es pawl means.
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Other features and advantages of the present invention will ~ecome apparent from the following description in reference to the accompanying drawings, in which:
- Figure 1 is a perspective view of a sewing machine and foot controller according to the present invention; -Figure 2 is an end view of the working mechanism of the sewing machine according to the present invention;
Figure 3 is a partial rear side view of the hand wheel end of the sewing machine of Figure 1, the housing having been broken away to illustrate constructional features thereof;
Figure 4 is a partial vertical cross-sectional view of the hand wheel end of the sewing machine according to the present invention, taken along the centreline of the upper shaft;
Figure 5 is a plan view of the portion of the sewing machine illustrated in Figure 4;
Figure 6 is a vertical cross-sectional view of the hand wheel end of the sewing machine, illustra-ting the mounting condition of the hand wheel;
Figure 7 is an exploded perspective view of the oper-ating parts of the sewing machine according : to the present invention;
Figure 8 is a perspective view of the belt wheel àccording to the present invention;
_ 3a -Figure 9 is a sectional view of the sewing machine taken along the line A-A' o Figure 3, Figure 10 is a perspective view of the pawl wheel and releasing cam member, illustrating one mode of operation thereof, Figure 11 is a vertical section illustrating the operation of the sewing machine, wherein the cam and pawl wheel have come to a predeter-mined angular position for receiving one .
of the pawls in the aligned recesses provided thereon;
Figure 12 is a view similar to Figure 10, illustrating a further position of operation of component parts of the machine, Figure 13 is a view similar to Figure 11, illustrating a further position of the component parts during operation of the machine;
. Figure 14 is a view similar to Figures 10 and 12, illus-trating a further position of operation of component parts of the machine, Figure 15 is a side elevational view of the parts of the machine for the winding of thread, Figure 16 is an elevational view of the relationship between the pawl and the pawl wheel accord-ing to the present invention;
Figure 17 is an elevational view of the relationship between the stopper cam, the releasing cam and the pawl according to the present invention;
- Figure 18 is an elevational view illustrating the pawl being received in the recess formed on the releasing cam; and ' ' . :
1g~4886~ -Figure 19 is an elevational view of a further embodiment of the present invention.
In reference to Figures 1 to 8, numeral 1 denotes a machine housing; numeral 2 denotes a belt driven by a machine -:
motor 201 with a foot plate 202, reference numeral 3 denotes an intermediate pulley rotatably mounted in the machine housing and driven by the belt 2, reference numeral 4 indicates a second belt driven by the pulley 3, the belt 4 driving a belt wheel 5. The belt wheel 5 is rotatably mounted on a bushing 8 fixed to the upper shaft 6 by means of a screw 7. The rotary movement of the belt wheel can be transmitted to the upper shaft through a clutch device 9 provided between the belt wheel and the bushing. The belt wheel 5 has five pins 10 securely mounted on the inner reces-sed face thereof surrounded by a flange 13 with a roullet face 106. Five pawls 11 are each pivotally mounted on pins 10, as seen in Figure 8, so that as the belt wheel is rotated, the pawls 11 rotate about their respective pins 10 in the clockwise direction due to the centrifugal force and the outer backsides . of the pawls are each urged against the inner transverse peripheral i 20 wall 12 of the flange 13.
: As illustrated in Figures 2 and 7, the clutch device 9 comprises a substantially flat plate 15 and a cylindrical roller 18. The flat plate 15 is placed at the bottom of a groove 14 formed on the bushing 8 substantially in parallel with the upper shaft 6, and the roller 18 is placed in the space defined by the groove 14 and a part of the inner peripheral surface 17 of the bore 16 of the belt wheel 5. The roller 18 is placed in and held by an opening 21 of a transverse arm 20 projecting from a stopper cam member 19. As the stopper cam member 19 is turned in the counterclockwise direction relative to the bushing 8, the roller is shifted and pushed into a narrower space defined by . -- 5 --16)48862 the groove 14 and a part of the inner surface 17 of the bore 16 of the belt wheel 5, and the belt wheel 5 and bushing 8 are inter-connected by the roller 18. As a result, when belt wheel 5 is rotated, the rotational movement is transmitted to the upper shaft 6. On the other hand, as the stopper cam member 19 is turned in a clockwise direction relative to the bushing 8, the roller 18 is shifted to a wider space defined by the groove 14 of the bushing and a part of the inner periphery 17 of the axial bore 16 of the belt wheel 5. Therefore, when the belt wheel is rotated, the same rotates relative to the bushing 8.
As illustrated in Figure 7, the stopper cam member 19 is substantially of cylindrical form, having an annular base 22 and an axial collar 25. The annular base 22 is provided with a cam having a shoulder 23 on the periphery thereof. The collar 25 supports the transverse arm 20, the collar 25 being formed with an arcuate groove in the periphery thereof for receiving a coil spring 26. A pair of arcuate slots 28, 29 are formed in the stopper cam member 19 in diametrically opposite relationship to -each other, the slots extending axially through the collar 25 and the annular base 22 of the stopper cam member. One end 30 of each slot in the counterclockwise direction is enlarged. Cushion elements 31, 32, which may be made of polyurethane or similar material, are inserted into the enlarged ends 30 of the slots respectively, the elements 31, 32 each having a head 33 fitted to the enlarged ends 30 of the slots 28, 29. The cushion elements 31, 32 absorb the impact which may be applied to the stopper cam member 19 by the upper shaft 6 via stepped screws 34, 35 when the upper shaft 6 is stopped. The pair of stepped screws 34, 35 are inserted into the slots 28, 29 and screwed into the opposed face of the bushing 8. The stopper cam member 19 also has a central hub 36 which is inserted into axial openings 39 and 40 1~4~3862 of a pawl wheel 37 and a washer 38 respectively, for holding the same thereon. A coil spring 41, which is mounted around the upper shaft 6 of the sewing machine and normally urges the stop-per cam member 19 in a counterclockwise direction relative to the upper shaft 6, as seen in Figure 7, has one end 42 inserted into the opposed face of the stopper cam member 19 and its other end 43 inserted into the opposed face of a sprocket 44 which is rigidly mounted on upper shaft 6. Sprocket 44 engages a timing belt 45 which is driven by the upper shaft, the timing belt 45 driving a lower shaft, not shown, and related members of the sewing machine.
Further, in reference to Figure 7, reference numeral 46 denotes a releasing cam member having a flange 47 forming the largest diameter of the flange. On one side of the flange facing the stopper cam 19, the releasing cam member is provided with a projection 49 for releasing a stopper 48 which is described in detail below. On the opposite side of the flange 47, the releasing cam member is provided with a small diameter collar 51. The collar 51 is formed with four recesses 50 for receiving the pawls 20 11. The central bore 53 of the releasing cam member 46 has sub-stantially the same diameter and axial length as the outer dia-meter and axial length of the collar 25 of the stopper cam member 19. The bore 53 receives the collar 25 of the stopper cam member 19. A projection 55 is provided on the periphery 54`of the bore 53 of the releasing cam member 46. When the releasing cam member 46 and the stopper cam member 19 are fitted together, the coil spring 26 in the arcuate recess 27 of the collar 25 bears against the projection 55 and one end wall of the recess 27 in a clock-wise direction. As a result, coil spring 26 applies a pressure to the releasing cam in a counterclockwise direction relative to bushing 8, as seen in Figures 17 and 18. Axial movement of the releasing cam member 46 is limited by the pawl wheel 37, pawl wheel A
1~48862 37 being attached to the opposed face of the collar 25 of the stopper cam member 19 by means of screws 56, 56. The releasing cam member 46 is free to turn within a limited angular distance relative to the stopper cam member 19.
The pawl wheel 37 is provided with four cam faces 57 -. . .
on the periphery thereof. The projections 52 of the respective pawls 11 are thick enough to engage simultaneously both the cam faces 57 and the periphery of collar 51. If the releasing cam member 46 is turned relative to the pawl wheel 37 when one of the projections 52 of the respective pawls 11 is in engagement with one of the aligned recesses of the releasing cam member 46 and the pawl wheel 37, the projection is moved along the cam face 57 (see Figures 7 and 13) and released from the recess 50 of the releasing cam member 46. The diametrically opposite slot 58, 59 of the pawl wheel 37 receive the cylindrical portions . , 60, 61 of the stepped screws 34, 35 respectively, and an opening . 62 of the pawl wheel 37 receives the transverse arm 20 of the . stopper cam member 19. The washer 38, which is securely attached to the bushing by means of the stepped screws 34, 35, determines the axial position of the belt wheel 5, and also acts as a guide for the belt wheel when the latter is rotated relative to the -:
bushing.
Referring further to Figure 7, reference numeral 63 denotes a holder for the belt wheel 5. The holder 63 has a pair of flexible arms 64, 65 which are integral with the holder and transversely bent to the side of the holder 63 facing hand wheel 69 from diametrically opposite reduced positions of the holder 63. The holder 63 is securely attached to the opposed face of the bushing 8 by means of fastening screws 66, 67. Reference numeral 68 denotes an elastic washer which is placed loosely around the bushing 8 between the holder 63 and the belt wheel 5, .. . .
- . , . . ~, -, . . . .
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- `-- 1C1 48862 and is lightly pressed against the belt wheel 5, as seen in Figure 4.
AS illustrated in Fi~ure 6, the hand wheel 69 is pro-vided with a central boss 70 which is diametrically enlarged at the central portion thereof, as indicated by reference numeral 71. The enlarged portion 71 of the boss 70 is clamped by the pair of flexible arms 64, 65 of the holder 63 when the hand wheel 69 is mounted on upper shaft 6, as shown. The hand wheel is, therefore, prevented from slipping off of upper shaft 6.
10 As best seen in Figure 4, the boss 70 of the hand wheel 69 is provided with a hole 72 which receives the head 73 of the screw 66 referred to above. As a result the hand wheel 69 is prevented from being turned relative to the upper shaft 6, such that the machine operator can determine the angular position of the upper shaft 6 by means of the hand wheel 69. If necessary, the hand wheel can be easily removed from the upper shaft 6, by pulling the same towards the left, as seen in Figure 3.
The mechanism described above is mounted on the upper shaft 6 of the sewing machine. The present invention provides a device for controlling the mechanism. In reference to Figures 7, 9, 11, 13, 15, 17 and 18, numeral 48 designates a stopper lever which is pivotally mounted on a shaft 74 secured to the machine housing 1. One end 75 of the lever 74 engages the peri-phery of the flange 47 and the projection 49 of the releasing cam memher 46. The other end 76 of the lever is connected to one end of a tension spring 78, the other end of which is anchored to a support plate 77, as seen in Figure 2, the support plate being rigidly attached to the machine housing 1. Thus, the stopper lever 48 is normally urged in a clockwise direction. The stopper lever 48 is formed with a downward projection 79 between its pivot point and the end 76 thereof, as shown. The downward pro-- , . .
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' . - ' :,: - '. ' : ~
-~ 14886~
jection 79 engages a selecting cam 81 which i5 pivotally mounted on a pin 80, pin 80 being secured to the machine housing 1. The selecting cam 81 has an axial bore 82, an arc portion 83, a recess 85 on one side of the arc portion, a recess 84 on the ; opposite side of the arc portion, a cam face 86 adjacent the recess 84, and an arm 87. The radii of curvature of the recesses 84, 85 are the same as that of the projection 79 of the stopper ; lever 48. The projection 79 engages the recesses 84 and 85 re-; spectively and holds the selecting cam member 81 in two angular positions thereof relative to the pin 80, whereby the sewing machine is set to continuously rotate at high speed or at a lower speed for sewing normal continuous stitches. In this case, an electrical connection is made at the terminals 89 of a switching device 88. An upper end of a rod 90 is connected to the outer end of arm 87 of the selecting cam 81, while the lower end of rod 90 is connected to an operating knob 91. The knob is substantially T-shaped and is provided with a recess 92 in - -its inner face, the recess 92 receiving a connecting piece 93.
An inner face 94 of the connecting piece 93 is made flat to pro-vide a suitable contact with the terminals 89 of the switching device 88. The terminals 89 comprise terminals labelled a, b, c and d in Figure 7. When the connecting piece 93 contacts the terminals a and b simultaneously, the sewing machine is set to sew ordinary continuous stitches at high speed. When the connect-ing piece 93 contacts terminals b and c simultaneously, the sew-ing machine is set to sew ordinary continuous stitches at a lower speed. When the connecting piece 93 contacts the terminals c and d simultaneously, the sewing machine is set to sew inter-mittent stitches.
Referring to Figures 2, 3, 5 and 7, a thread winding device will be described. Reference numeral 95 denotes a double ; . ' , ~ ~ ~ ' ' 1~4886Z
arm lever which is rotatably mounted on the shaft 74 together with the stopper lever 48. One arm 96 of the double arm lever 95 engages the stopper cam member 19 when it is turned in the clockwise direction by the turning movement of a lever 97 having arms 101 and 103. One end of a tension spring 99 is connected to a hole 98 of the double arm lever 95 and the other end is anchored to the support plate 77. Thus, the double arm lever 95 is usually urged in the clockwise direction by the tension spring 99. The other arm 100 of the double arm lever 95 is en-gaged by the arm 101 of the lever 97, as seen in Figure 4, and is usually urged in a counterclockwise direction against the action of the tension spring 99. The lever 97 is pivotally mounted on the machine housing 1 and is normally placed in a released condition by a bistable spring 102 which urges the lever 97 in a clockwise direction until the arm 103 of the lever is engaged by a stop pin 104, pin 104 being secured to the machine housing 1, as seen in Figure 5. When the thread winding operation is carried out, the lever 97 is manually turned in a counterclockwise direction against the action of the bistable spring 102, and a gum wheel 105, which is rotatably mounted on the lever 97, is pressed against the roullet face 106 of the belt wheel 5. The lever 97 and the gum wheel 105 are maintained in this position by the action of the bistable spring 102. When the thread winding device is set in this operating condition, the arm 101 of the lever 97 releases the double arm lever 95.
The operation of the structure according to the present invention will now be described. In order to set the sewing machine to sew the ordinary continuous stitches, the operating knob 91 is shifted to its uppermost position, bringing the connect-ing piece 93 into contact with terminals a and b. Simultaneously, an electric circuit, not illustr~ted ln the drawings, applies a ;
", source voltage to the machine motor. As the result, in accordance with the degree of pressure applied to the foot controller of the sewing machine, the machine motor can be rotated with a voltage between zero and maximum voltage. Thus, when the operating knob 91 is shifted to the uppermost position, the rod 90 is upwardly shifted and turns the selecting cam 81 in a counterclock-wise direction, the projection 79 of the stopper lever 48 engaging the recess 85 of the selecting cam 81. The stopper lever 48 is turned in a counterclockwise direction and the end 75 of the lever 48 is shifted out of the path of rotation of the cam 24 of the stopper cam member 19 and of ~he projection 49 of the re-leasing cam member 46. The stopper cam member l9,is-, therefore, turned a little in a counterclockwise direction under the action of the spring 41, and accordingly the roller 18 of the clutch device 9 is shifted into the narrow space between the periphery 17 of the bore 16 of the belt wheel 5 and the groove 14 of the bushing 8. As a result, the belt wheel 5 and the upper shaft 6 are interconnected. Therefore, when the foot controller is pressed, the upper shaft 6 of the sewing machine is continuously rotated, and ordinary continuous stitches are produced. When the operating knob 91 is shifted to the intermediate position wherein the connectlng piece 93 contacts terminals b and c, an electric circuit is so formed as to continuously drive the sewing machine at a lower speed. In both cases, upper shaft 6, and hand wheel 69 are stopped at an indefinite angular position after the foot controller is released to de-energize the machine motor. The desired needle position after the sewing machine stops can be obtained by manually rotating the hand wheel.
The intermittent drive of the invention will now be described. When the operating knob 91 is shifted to the lower-most position wherein the connecting piece 93 contacts terminals , :
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c and d, the selecting cam 81 is turned in a counterclockwise direction, and stopper lever 48 is turned in a clockwise direction by the tension spring 78 until the projection 79 of the lever 48 engages the cam face 86 of the selecting cam 81. Thus, the arm 75 of the stopper lever 48 is shifted into the path of rotation of the cam 24 of the stopper cam member 19 and of the projection 49 of the releasing cam member 46. In this position, as illus-trated in Figures 8 and 9, the releasing cam member 46 and the pawl wheel 37 are so arranged that the cam projections 50' of the member 46 are opposite to the recesses 57' of the wheel 37 respectively, and the cam projections 57 of the wheel 37 are opposite to the recesses 50' o~ the member 46 respectively.
When the foot controller is pressed, the upper shaft 6 is rotated at a lower speed, and the projection 49 of the releasing cam member 46 approaches the end 75 of the stopper lever 48. It is to be noted that the stopper-cam member 19 is rotated by the upper shaft through the intermediate spring 41 and that the releasing cam 46 is rotated by thé stopper cam member 19 through the intermediate coil spring 26.
As illustrated in Figure 10, when the projection 49 of the releasing cam member 46 comes into engagement with the end - 75 of the stopper lever 48, the releasing cam member 46 is stop-ped first. The stopper cam member 19, however, continues to rotate against the action of the spring 26 and is stopped when the shoulder 23 of the cam 24 of the stopper cam member 19 comes into engagement with the end 75 of the stopper lever 48. The - upper shaft 6, therefore, is prevented from rotating. At this stage, the releasing cam member 46 and the pawl wheel 37 are so ~ -arranged that the cam projections 50' of the member 46 and the cam projections 57 of the wheel 37 are aligned respectively and that the recesses 50 of the member 46 and the recesses 57' of ' :' ' ' ' . ' , ',: . ' ' ` 1048862 the wheel 37 also aligned. Then, one of the pawls 11 on the belt wheel 5 drops into one of the aligned recesses 50, 57'. As the belt wheel 5 is continuously rotated, the belt wheei leaves behind the roller 18 of the clutch device 9 while the roller 18 is shifted to a side space between the periphery 17 of the bore 16 of the belt wheel 5 and the groove 14 of the bushing 8 where the roller is spaced from the periphery 17 of the bore 16 of the belt wheel 5. As a result, the belt wheel 5 is disconnected from the bushing 8 and the upper shaft 6 and rotates relative to 10 the upper shaft 6 as long as the foot controller is pressed.
As the bushing 8 and therefore the upper shaft 6 had been rotating with considerable inertia, the upper shaft 6 comes to a standstill when the bushing 8 rotates within an angular distance correspond-ing to the length of the arcuate slots 28, 29 and the stepped screws 34, 35 with the cylindrical portions 60, 61 bump against the cushion elements 31, 32, placed in the slots 28, 29. The impact at the stopping time of the upper shaft 6 is absorbed by the cushion elements, and therefore the sounds or noises, which would otherwise be produced each time the sewing machine is 20 stopped during the intermittent stitching operation, are reduced.
In this regard it is noted that the upper shaft 6 is always stopped at a predetermined angular position for stopping the machine needle substantially at the upper dead point location where the needle is separated from the sewn material. Since the belt wheel 5 continues to rotate relative to the upper shaft 6 as long as the foot controller is pressed down, the pawls 11 on the belt wheel 5 are all urged in the radially outward direction relative to the belt wheel due to the centrifugal force, such that the projections 52 of pawls 11 are prevented from engaging 30 the aligned recesses 50, 57' of the releasing cam member 46 and of the pawl wheel 37 respectively.
11~)4886Z
When the controller is released, the belt wheel comes to a standstill, and the centrifugal force of the belt wheel dissipates. As a result, one of the pawls 11 located at the upper part of the stopped belt wheel, drops into one of the aligned recesses 50, 57' of the pawl wheel 37 and the releasing cam member 46, as illustrated in Figure 11. Since the belt wheel 5 stops at an indefinite angular position, it does not always happen that the pawl drops into the aligned recess when the belt wheel is stopped. This is, however, not a matter of importance because the pawl eventually drops into the recess as the belt wheel is rotated in response to further pressure applied to the foot-controller.
When the foot controller is pressed again, the belt wheel 5 is rotated in the direction as indicated by the arrow mark in Figure 12 and the pawl 11, which is in engagement with one of the aligned recesses 50, 57', rotates the releasing cam member 46 while allowing the compression spring 26 to expand in the member 46, as illustrated in Figure 18. As the belt wheel rotates, the pawl 11 with the projection 52 slides on the sloped face of the recess 57 of the pawl wheel 37 which extends from the bottom of the recess to the radial periphery of the pawl wheel 37 on the side of the recess in the rotation direction so illus-trated in Figure 16. Thus, the projection 52 of the pawl 11 is brought to the upper periphery of the pawl wheel 11 and of the releasing cam member 46 while rotating the releasing cam member, as illustrated in Figures 13 and 17. Simultaneously, the projec-tion 49 of the releasing cam member 46 pushes the end 75 of the - stopper lever 48 against the action of the tension spring 78, thereby disengaging the end 75 of the lever 48 from the shoulder 23 of the cam 24 on the periphery of the stopper cam member 19.
As the result, the spring 41, situated around the upper shaft 6, , ', ' ' , - . ' , . . ' ' :. ' , as seen in Figure 6, and which has been distorted a little when the upper shaft was stopped, turns the stopper cam member 19 relative to the bushing 8 in the direction as indicated by the arrow mark in Figure 12. Then the roller 18 of the clutch device 19 as seen in Figures 1 and 6, is brought to the narrow space defined between the groove 14 of the bushing 8 and the bore face 17 of the belt wheel 5. The belt wheel 5 and the bushing 8 are again interconnected via the roller 18, and the upper shaft 6 is rotated. Thus, one stitch is sewn. The upper shaft 6, however, is stopped at a predetermined angular position after one complete rotation thereof-by the aforementioned opera-tion of the associated component parts. In this manner, it will be apparent that the upper shaft 6 of the sewing machine is stopped at a predetermined angular position after one complete rotation thereof by repeatedly pressing and releasing the foot controller of the sewing machine. With the structure and - function of this invention, it will be apparent that the operator of sewing machine is able to use both hands to deal with the sewn material during the basting operation, and that the operator of the sewing machine is able to move the sewn material placed under the machine needle with both hands, the machine needle being retained in an upper position spaced from the sewn material for a desired distance and to a desired direction for making basting stitches.
Figure 19 illustrates a further embodiment of the present invention, wherein a single pawl 111 is pivotally mounted on the belt wheel 5 in the same manner as the pawls 11 of Figure 7. The pawl 111 is normally biased against the periphery of the releasing cam member 109 and of the pawl wheel 110 by a compression spring 108 which is provided between the back of the pawl and the inner transverse peripheral wall 12 of the -~41~86Z
flange 13 of the belt wheel 5. The pawl 111 is, as in the case of pawls 11 in Figure 7, turned in the radially outward direction relative to the belt wheel 5 against the action of t~e spring by centrifugal force when the belt wheel is rotated in the direction as indicated by the arrow mark. According to this embodiment, the releasing cam member 109 and the pawl wheel 110 are provided with cam faces of recesses and projections all around the periphery thereof. Describiny the thread winding of the sewing machine, initially, the operating knob 91 of the switch device 98 is shifted to its upper or intermediate position wherein the connecting element 93 of-the knob contacts the ter-minals a and b or terminals b and c ready for driving the sew-ing machine at high speed or a lower speed, to sew ordinary continuous stitches. Simultaneously, the stopper lever 48 is turned in the countercloc~cwise direction against the action of the tension spring 78 and the end 75 of the lever 48 is drawn out of the path of rotation of the cam 24 of the stopper cam :
member 19 and of the projection 49 of the releasing cam member 46. The lever 97 in Figure 4 is then manually turned in a counter-clockwise direction against the action of the bistable spring 102 so as to press the gum wheel 105, which is rotatably mounted on lever 97, against the roulette face 106 of the flange 13 of -:~
the belt wheel 5, the double arm lever 95 is, at the same time, released and turned in a clockwise direction by the action of the spring 99, as shown in Figure 6 and the arm 96 of the lever 95 is brought into the path of rotation of the cam 24 of the stopper cam member 19. The stopper cam member 19 is, therefore, stopped when the foot controller is pressed and the shoulder 23 of the cam 24 engages the arm 96 of the double arm lever 95 during the rotation thereof. As the result, the roller 18 of the clutch device 9 is shifted to a wide space defined by the groove 14 of : : .:
:1~4886Z
the bushing 8 and the inner periphery 17 of the central bore 16 of the belt wheel 5 where the roller 8 is spaced from the inner periphery 17 o~ the bore 16. The belt wheel 5 is therefore rotated relative to the bushing 8 and the upper shaft 6, whereby a thread is wound on a bobbin, not shown in the drawings, if the latter is mounted on the vertical shaft of the gum wheel, as illustrated in Figures 2 and 3.
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This invention relates generally to an intermittent driving device for sewing machines, and more particularly, to a device for intermittently driving a sewing machine and for stop-ping the same at a predetermined angular position after one complete rotation thereof each time the foot controller of the sewing machine is operated.
A sewing machine incorporating a device according to the present invention can be used to sew basting stitches in material, whereby the sewing machine is stopped after one complete ~
10 rotation in response to pressure applied to the foot controller. ~ -The impact and/or noise occurring when the sewing machine stops is reduced, and the machine motor is protected from overloading while the sewing machine is stopped.
Heretofore, sewing machines incorporating similar devices have been used to sew basting stitches in sewn material.
However, with these conventional sewing machines, the machine operator has to use one hand to intermittently drive the sewing machine while the other hand manipulates the sewn material. The machine operator, therefore, has had difficulties in sewing basting stitches with these conventional sewing machines.
Further, it is also known to provide sewing machines which intermittently rotate automatically in a predetermined time interval. Such sewing machines have been not convenient for sewing basting stitches because the machine operator cannot control the rotation of the sewing machine at will, especially when sewing curved or other parts of the material requiring special attention. Additionally, other known sewing machines have been provided which are intermittently driven in one complete rotation each time when the machine controller is pressed. These sewing machines are, however, forcibly stopped in such a manner that the driving power of the machine motor is wholly applied to ~ .
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the device for stopping the machine at a predetermined angular position. These sewing machines, therefore, produce loud sounds or noises each time the sewing machine stops, resulting in ex-cessive wear of machine parts and overloading of the sewing machine motor and other driving parts.
So long as all the aforementioned sewing machines are sold as household sewing machines, they should be supplied at as low a price as possible. However, such sewing machines utilize electromagnetic solenoids and associated electrical circuitry for controlling the solenoids, resulting in high production costs which render the sewing machines impractical for domestic purposes.
The present invention proposes to overcome the defects and disadvantages of conventional sewing machines such as those referred to above by providing a compact sewing machine which can be intermi~tently driven. The sewing machine can be started and stopped, without any shocks or sounds, at a predetermined angular position after one complete rotation thereof each time the foot controller is operated. Further, the machine can be selectively driven at high speed, a lower speed, or in an intermittent rota-tion, and can be started or stopped without overloading the motor.
According to the present invention, there is provideda sewing machine with an intermittent driving device comprising a machine housing, an upper shaft rotatably journalled in the machine housing, a belt wheel mounted on the upper shaft and rotatable relative to the upper shaft, clutch means provided between the upper shaft and the belt wheel and operable to connect and disconnect the belt wheel to and from the upper shaft, actua-ting means for actuating the clutch means to operate the same to a first position for connecting the belt wheel to the upper shaft and to a second position for disconnecting the belt wheel from the upper shaft, stopper means for engaging and stopping the 1~48862 actuating means, releasing means actuated to release the actuating means from the stopper means and means for actuating the releasing means to release the actuating means from the stopper means.
The releasing means suitably comprises a releasing cam means; and the means for actuating such releasing cam means to release the actuating means from the stopper means suitably compri~es pawl means.
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Other features and advantages of the present invention will ~ecome apparent from the following description in reference to the accompanying drawings, in which:
- Figure 1 is a perspective view of a sewing machine and foot controller according to the present invention; -Figure 2 is an end view of the working mechanism of the sewing machine according to the present invention;
Figure 3 is a partial rear side view of the hand wheel end of the sewing machine of Figure 1, the housing having been broken away to illustrate constructional features thereof;
Figure 4 is a partial vertical cross-sectional view of the hand wheel end of the sewing machine according to the present invention, taken along the centreline of the upper shaft;
Figure 5 is a plan view of the portion of the sewing machine illustrated in Figure 4;
Figure 6 is a vertical cross-sectional view of the hand wheel end of the sewing machine, illustra-ting the mounting condition of the hand wheel;
Figure 7 is an exploded perspective view of the oper-ating parts of the sewing machine according : to the present invention;
Figure 8 is a perspective view of the belt wheel àccording to the present invention;
_ 3a -Figure 9 is a sectional view of the sewing machine taken along the line A-A' o Figure 3, Figure 10 is a perspective view of the pawl wheel and releasing cam member, illustrating one mode of operation thereof, Figure 11 is a vertical section illustrating the operation of the sewing machine, wherein the cam and pawl wheel have come to a predeter-mined angular position for receiving one .
of the pawls in the aligned recesses provided thereon;
Figure 12 is a view similar to Figure 10, illustrating a further position of operation of component parts of the machine, Figure 13 is a view similar to Figure 11, illustrating a further position of the component parts during operation of the machine;
. Figure 14 is a view similar to Figures 10 and 12, illus-trating a further position of operation of component parts of the machine, Figure 15 is a side elevational view of the parts of the machine for the winding of thread, Figure 16 is an elevational view of the relationship between the pawl and the pawl wheel accord-ing to the present invention;
Figure 17 is an elevational view of the relationship between the stopper cam, the releasing cam and the pawl according to the present invention;
- Figure 18 is an elevational view illustrating the pawl being received in the recess formed on the releasing cam; and ' ' . :
1g~4886~ -Figure 19 is an elevational view of a further embodiment of the present invention.
In reference to Figures 1 to 8, numeral 1 denotes a machine housing; numeral 2 denotes a belt driven by a machine -:
motor 201 with a foot plate 202, reference numeral 3 denotes an intermediate pulley rotatably mounted in the machine housing and driven by the belt 2, reference numeral 4 indicates a second belt driven by the pulley 3, the belt 4 driving a belt wheel 5. The belt wheel 5 is rotatably mounted on a bushing 8 fixed to the upper shaft 6 by means of a screw 7. The rotary movement of the belt wheel can be transmitted to the upper shaft through a clutch device 9 provided between the belt wheel and the bushing. The belt wheel 5 has five pins 10 securely mounted on the inner reces-sed face thereof surrounded by a flange 13 with a roullet face 106. Five pawls 11 are each pivotally mounted on pins 10, as seen in Figure 8, so that as the belt wheel is rotated, the pawls 11 rotate about their respective pins 10 in the clockwise direction due to the centrifugal force and the outer backsides . of the pawls are each urged against the inner transverse peripheral i 20 wall 12 of the flange 13.
: As illustrated in Figures 2 and 7, the clutch device 9 comprises a substantially flat plate 15 and a cylindrical roller 18. The flat plate 15 is placed at the bottom of a groove 14 formed on the bushing 8 substantially in parallel with the upper shaft 6, and the roller 18 is placed in the space defined by the groove 14 and a part of the inner peripheral surface 17 of the bore 16 of the belt wheel 5. The roller 18 is placed in and held by an opening 21 of a transverse arm 20 projecting from a stopper cam member 19. As the stopper cam member 19 is turned in the counterclockwise direction relative to the bushing 8, the roller is shifted and pushed into a narrower space defined by . -- 5 --16)48862 the groove 14 and a part of the inner surface 17 of the bore 16 of the belt wheel 5, and the belt wheel 5 and bushing 8 are inter-connected by the roller 18. As a result, when belt wheel 5 is rotated, the rotational movement is transmitted to the upper shaft 6. On the other hand, as the stopper cam member 19 is turned in a clockwise direction relative to the bushing 8, the roller 18 is shifted to a wider space defined by the groove 14 of the bushing and a part of the inner periphery 17 of the axial bore 16 of the belt wheel 5. Therefore, when the belt wheel is rotated, the same rotates relative to the bushing 8.
As illustrated in Figure 7, the stopper cam member 19 is substantially of cylindrical form, having an annular base 22 and an axial collar 25. The annular base 22 is provided with a cam having a shoulder 23 on the periphery thereof. The collar 25 supports the transverse arm 20, the collar 25 being formed with an arcuate groove in the periphery thereof for receiving a coil spring 26. A pair of arcuate slots 28, 29 are formed in the stopper cam member 19 in diametrically opposite relationship to -each other, the slots extending axially through the collar 25 and the annular base 22 of the stopper cam member. One end 30 of each slot in the counterclockwise direction is enlarged. Cushion elements 31, 32, which may be made of polyurethane or similar material, are inserted into the enlarged ends 30 of the slots respectively, the elements 31, 32 each having a head 33 fitted to the enlarged ends 30 of the slots 28, 29. The cushion elements 31, 32 absorb the impact which may be applied to the stopper cam member 19 by the upper shaft 6 via stepped screws 34, 35 when the upper shaft 6 is stopped. The pair of stepped screws 34, 35 are inserted into the slots 28, 29 and screwed into the opposed face of the bushing 8. The stopper cam member 19 also has a central hub 36 which is inserted into axial openings 39 and 40 1~4~3862 of a pawl wheel 37 and a washer 38 respectively, for holding the same thereon. A coil spring 41, which is mounted around the upper shaft 6 of the sewing machine and normally urges the stop-per cam member 19 in a counterclockwise direction relative to the upper shaft 6, as seen in Figure 7, has one end 42 inserted into the opposed face of the stopper cam member 19 and its other end 43 inserted into the opposed face of a sprocket 44 which is rigidly mounted on upper shaft 6. Sprocket 44 engages a timing belt 45 which is driven by the upper shaft, the timing belt 45 driving a lower shaft, not shown, and related members of the sewing machine.
Further, in reference to Figure 7, reference numeral 46 denotes a releasing cam member having a flange 47 forming the largest diameter of the flange. On one side of the flange facing the stopper cam 19, the releasing cam member is provided with a projection 49 for releasing a stopper 48 which is described in detail below. On the opposite side of the flange 47, the releasing cam member is provided with a small diameter collar 51. The collar 51 is formed with four recesses 50 for receiving the pawls 20 11. The central bore 53 of the releasing cam member 46 has sub-stantially the same diameter and axial length as the outer dia-meter and axial length of the collar 25 of the stopper cam member 19. The bore 53 receives the collar 25 of the stopper cam member 19. A projection 55 is provided on the periphery 54`of the bore 53 of the releasing cam member 46. When the releasing cam member 46 and the stopper cam member 19 are fitted together, the coil spring 26 in the arcuate recess 27 of the collar 25 bears against the projection 55 and one end wall of the recess 27 in a clock-wise direction. As a result, coil spring 26 applies a pressure to the releasing cam in a counterclockwise direction relative to bushing 8, as seen in Figures 17 and 18. Axial movement of the releasing cam member 46 is limited by the pawl wheel 37, pawl wheel A
1~48862 37 being attached to the opposed face of the collar 25 of the stopper cam member 19 by means of screws 56, 56. The releasing cam member 46 is free to turn within a limited angular distance relative to the stopper cam member 19.
The pawl wheel 37 is provided with four cam faces 57 -. . .
on the periphery thereof. The projections 52 of the respective pawls 11 are thick enough to engage simultaneously both the cam faces 57 and the periphery of collar 51. If the releasing cam member 46 is turned relative to the pawl wheel 37 when one of the projections 52 of the respective pawls 11 is in engagement with one of the aligned recesses of the releasing cam member 46 and the pawl wheel 37, the projection is moved along the cam face 57 (see Figures 7 and 13) and released from the recess 50 of the releasing cam member 46. The diametrically opposite slot 58, 59 of the pawl wheel 37 receive the cylindrical portions . , 60, 61 of the stepped screws 34, 35 respectively, and an opening . 62 of the pawl wheel 37 receives the transverse arm 20 of the . stopper cam member 19. The washer 38, which is securely attached to the bushing by means of the stepped screws 34, 35, determines the axial position of the belt wheel 5, and also acts as a guide for the belt wheel when the latter is rotated relative to the -:
bushing.
Referring further to Figure 7, reference numeral 63 denotes a holder for the belt wheel 5. The holder 63 has a pair of flexible arms 64, 65 which are integral with the holder and transversely bent to the side of the holder 63 facing hand wheel 69 from diametrically opposite reduced positions of the holder 63. The holder 63 is securely attached to the opposed face of the bushing 8 by means of fastening screws 66, 67. Reference numeral 68 denotes an elastic washer which is placed loosely around the bushing 8 between the holder 63 and the belt wheel 5, .. . .
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- `-- 1C1 48862 and is lightly pressed against the belt wheel 5, as seen in Figure 4.
AS illustrated in Fi~ure 6, the hand wheel 69 is pro-vided with a central boss 70 which is diametrically enlarged at the central portion thereof, as indicated by reference numeral 71. The enlarged portion 71 of the boss 70 is clamped by the pair of flexible arms 64, 65 of the holder 63 when the hand wheel 69 is mounted on upper shaft 6, as shown. The hand wheel is, therefore, prevented from slipping off of upper shaft 6.
10 As best seen in Figure 4, the boss 70 of the hand wheel 69 is provided with a hole 72 which receives the head 73 of the screw 66 referred to above. As a result the hand wheel 69 is prevented from being turned relative to the upper shaft 6, such that the machine operator can determine the angular position of the upper shaft 6 by means of the hand wheel 69. If necessary, the hand wheel can be easily removed from the upper shaft 6, by pulling the same towards the left, as seen in Figure 3.
The mechanism described above is mounted on the upper shaft 6 of the sewing machine. The present invention provides a device for controlling the mechanism. In reference to Figures 7, 9, 11, 13, 15, 17 and 18, numeral 48 designates a stopper lever which is pivotally mounted on a shaft 74 secured to the machine housing 1. One end 75 of the lever 74 engages the peri-phery of the flange 47 and the projection 49 of the releasing cam memher 46. The other end 76 of the lever is connected to one end of a tension spring 78, the other end of which is anchored to a support plate 77, as seen in Figure 2, the support plate being rigidly attached to the machine housing 1. Thus, the stopper lever 48 is normally urged in a clockwise direction. The stopper lever 48 is formed with a downward projection 79 between its pivot point and the end 76 thereof, as shown. The downward pro-- , . .
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jection 79 engages a selecting cam 81 which i5 pivotally mounted on a pin 80, pin 80 being secured to the machine housing 1. The selecting cam 81 has an axial bore 82, an arc portion 83, a recess 85 on one side of the arc portion, a recess 84 on the ; opposite side of the arc portion, a cam face 86 adjacent the recess 84, and an arm 87. The radii of curvature of the recesses 84, 85 are the same as that of the projection 79 of the stopper ; lever 48. The projection 79 engages the recesses 84 and 85 re-; spectively and holds the selecting cam member 81 in two angular positions thereof relative to the pin 80, whereby the sewing machine is set to continuously rotate at high speed or at a lower speed for sewing normal continuous stitches. In this case, an electrical connection is made at the terminals 89 of a switching device 88. An upper end of a rod 90 is connected to the outer end of arm 87 of the selecting cam 81, while the lower end of rod 90 is connected to an operating knob 91. The knob is substantially T-shaped and is provided with a recess 92 in - -its inner face, the recess 92 receiving a connecting piece 93.
An inner face 94 of the connecting piece 93 is made flat to pro-vide a suitable contact with the terminals 89 of the switching device 88. The terminals 89 comprise terminals labelled a, b, c and d in Figure 7. When the connecting piece 93 contacts the terminals a and b simultaneously, the sewing machine is set to sew ordinary continuous stitches at high speed. When the connect-ing piece 93 contacts terminals b and c simultaneously, the sew-ing machine is set to sew ordinary continuous stitches at a lower speed. When the connecting piece 93 contacts the terminals c and d simultaneously, the sewing machine is set to sew inter-mittent stitches.
Referring to Figures 2, 3, 5 and 7, a thread winding device will be described. Reference numeral 95 denotes a double ; . ' , ~ ~ ~ ' ' 1~4886Z
arm lever which is rotatably mounted on the shaft 74 together with the stopper lever 48. One arm 96 of the double arm lever 95 engages the stopper cam member 19 when it is turned in the clockwise direction by the turning movement of a lever 97 having arms 101 and 103. One end of a tension spring 99 is connected to a hole 98 of the double arm lever 95 and the other end is anchored to the support plate 77. Thus, the double arm lever 95 is usually urged in the clockwise direction by the tension spring 99. The other arm 100 of the double arm lever 95 is en-gaged by the arm 101 of the lever 97, as seen in Figure 4, and is usually urged in a counterclockwise direction against the action of the tension spring 99. The lever 97 is pivotally mounted on the machine housing 1 and is normally placed in a released condition by a bistable spring 102 which urges the lever 97 in a clockwise direction until the arm 103 of the lever is engaged by a stop pin 104, pin 104 being secured to the machine housing 1, as seen in Figure 5. When the thread winding operation is carried out, the lever 97 is manually turned in a counterclockwise direction against the action of the bistable spring 102, and a gum wheel 105, which is rotatably mounted on the lever 97, is pressed against the roullet face 106 of the belt wheel 5. The lever 97 and the gum wheel 105 are maintained in this position by the action of the bistable spring 102. When the thread winding device is set in this operating condition, the arm 101 of the lever 97 releases the double arm lever 95.
The operation of the structure according to the present invention will now be described. In order to set the sewing machine to sew the ordinary continuous stitches, the operating knob 91 is shifted to its uppermost position, bringing the connect-ing piece 93 into contact with terminals a and b. Simultaneously, an electric circuit, not illustr~ted ln the drawings, applies a ;
", source voltage to the machine motor. As the result, in accordance with the degree of pressure applied to the foot controller of the sewing machine, the machine motor can be rotated with a voltage between zero and maximum voltage. Thus, when the operating knob 91 is shifted to the uppermost position, the rod 90 is upwardly shifted and turns the selecting cam 81 in a counterclock-wise direction, the projection 79 of the stopper lever 48 engaging the recess 85 of the selecting cam 81. The stopper lever 48 is turned in a counterclockwise direction and the end 75 of the lever 48 is shifted out of the path of rotation of the cam 24 of the stopper cam member 19 and of ~he projection 49 of the re-leasing cam member 46. The stopper cam member l9,is-, therefore, turned a little in a counterclockwise direction under the action of the spring 41, and accordingly the roller 18 of the clutch device 9 is shifted into the narrow space between the periphery 17 of the bore 16 of the belt wheel 5 and the groove 14 of the bushing 8. As a result, the belt wheel 5 and the upper shaft 6 are interconnected. Therefore, when the foot controller is pressed, the upper shaft 6 of the sewing machine is continuously rotated, and ordinary continuous stitches are produced. When the operating knob 91 is shifted to the intermediate position wherein the connectlng piece 93 contacts terminals b and c, an electric circuit is so formed as to continuously drive the sewing machine at a lower speed. In both cases, upper shaft 6, and hand wheel 69 are stopped at an indefinite angular position after the foot controller is released to de-energize the machine motor. The desired needle position after the sewing machine stops can be obtained by manually rotating the hand wheel.
The intermittent drive of the invention will now be described. When the operating knob 91 is shifted to the lower-most position wherein the connecting piece 93 contacts terminals , :
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c and d, the selecting cam 81 is turned in a counterclockwise direction, and stopper lever 48 is turned in a clockwise direction by the tension spring 78 until the projection 79 of the lever 48 engages the cam face 86 of the selecting cam 81. Thus, the arm 75 of the stopper lever 48 is shifted into the path of rotation of the cam 24 of the stopper cam member 19 and of the projection 49 of the releasing cam member 46. In this position, as illus-trated in Figures 8 and 9, the releasing cam member 46 and the pawl wheel 37 are so arranged that the cam projections 50' of the member 46 are opposite to the recesses 57' of the wheel 37 respectively, and the cam projections 57 of the wheel 37 are opposite to the recesses 50' o~ the member 46 respectively.
When the foot controller is pressed, the upper shaft 6 is rotated at a lower speed, and the projection 49 of the releasing cam member 46 approaches the end 75 of the stopper lever 48. It is to be noted that the stopper-cam member 19 is rotated by the upper shaft through the intermediate spring 41 and that the releasing cam 46 is rotated by thé stopper cam member 19 through the intermediate coil spring 26.
As illustrated in Figure 10, when the projection 49 of the releasing cam member 46 comes into engagement with the end - 75 of the stopper lever 48, the releasing cam member 46 is stop-ped first. The stopper cam member 19, however, continues to rotate against the action of the spring 26 and is stopped when the shoulder 23 of the cam 24 of the stopper cam member 19 comes into engagement with the end 75 of the stopper lever 48. The - upper shaft 6, therefore, is prevented from rotating. At this stage, the releasing cam member 46 and the pawl wheel 37 are so ~ -arranged that the cam projections 50' of the member 46 and the cam projections 57 of the wheel 37 are aligned respectively and that the recesses 50 of the member 46 and the recesses 57' of ' :' ' ' ' . ' , ',: . ' ' ` 1048862 the wheel 37 also aligned. Then, one of the pawls 11 on the belt wheel 5 drops into one of the aligned recesses 50, 57'. As the belt wheel 5 is continuously rotated, the belt wheei leaves behind the roller 18 of the clutch device 9 while the roller 18 is shifted to a side space between the periphery 17 of the bore 16 of the belt wheel 5 and the groove 14 of the bushing 8 where the roller is spaced from the periphery 17 of the bore 16 of the belt wheel 5. As a result, the belt wheel 5 is disconnected from the bushing 8 and the upper shaft 6 and rotates relative to 10 the upper shaft 6 as long as the foot controller is pressed.
As the bushing 8 and therefore the upper shaft 6 had been rotating with considerable inertia, the upper shaft 6 comes to a standstill when the bushing 8 rotates within an angular distance correspond-ing to the length of the arcuate slots 28, 29 and the stepped screws 34, 35 with the cylindrical portions 60, 61 bump against the cushion elements 31, 32, placed in the slots 28, 29. The impact at the stopping time of the upper shaft 6 is absorbed by the cushion elements, and therefore the sounds or noises, which would otherwise be produced each time the sewing machine is 20 stopped during the intermittent stitching operation, are reduced.
In this regard it is noted that the upper shaft 6 is always stopped at a predetermined angular position for stopping the machine needle substantially at the upper dead point location where the needle is separated from the sewn material. Since the belt wheel 5 continues to rotate relative to the upper shaft 6 as long as the foot controller is pressed down, the pawls 11 on the belt wheel 5 are all urged in the radially outward direction relative to the belt wheel due to the centrifugal force, such that the projections 52 of pawls 11 are prevented from engaging 30 the aligned recesses 50, 57' of the releasing cam member 46 and of the pawl wheel 37 respectively.
11~)4886Z
When the controller is released, the belt wheel comes to a standstill, and the centrifugal force of the belt wheel dissipates. As a result, one of the pawls 11 located at the upper part of the stopped belt wheel, drops into one of the aligned recesses 50, 57' of the pawl wheel 37 and the releasing cam member 46, as illustrated in Figure 11. Since the belt wheel 5 stops at an indefinite angular position, it does not always happen that the pawl drops into the aligned recess when the belt wheel is stopped. This is, however, not a matter of importance because the pawl eventually drops into the recess as the belt wheel is rotated in response to further pressure applied to the foot-controller.
When the foot controller is pressed again, the belt wheel 5 is rotated in the direction as indicated by the arrow mark in Figure 12 and the pawl 11, which is in engagement with one of the aligned recesses 50, 57', rotates the releasing cam member 46 while allowing the compression spring 26 to expand in the member 46, as illustrated in Figure 18. As the belt wheel rotates, the pawl 11 with the projection 52 slides on the sloped face of the recess 57 of the pawl wheel 37 which extends from the bottom of the recess to the radial periphery of the pawl wheel 37 on the side of the recess in the rotation direction so illus-trated in Figure 16. Thus, the projection 52 of the pawl 11 is brought to the upper periphery of the pawl wheel 11 and of the releasing cam member 46 while rotating the releasing cam member, as illustrated in Figures 13 and 17. Simultaneously, the projec-tion 49 of the releasing cam member 46 pushes the end 75 of the - stopper lever 48 against the action of the tension spring 78, thereby disengaging the end 75 of the lever 48 from the shoulder 23 of the cam 24 on the periphery of the stopper cam member 19.
As the result, the spring 41, situated around the upper shaft 6, , ', ' ' , - . ' , . . ' ' :. ' , as seen in Figure 6, and which has been distorted a little when the upper shaft was stopped, turns the stopper cam member 19 relative to the bushing 8 in the direction as indicated by the arrow mark in Figure 12. Then the roller 18 of the clutch device 19 as seen in Figures 1 and 6, is brought to the narrow space defined between the groove 14 of the bushing 8 and the bore face 17 of the belt wheel 5. The belt wheel 5 and the bushing 8 are again interconnected via the roller 18, and the upper shaft 6 is rotated. Thus, one stitch is sewn. The upper shaft 6, however, is stopped at a predetermined angular position after one complete rotation thereof-by the aforementioned opera-tion of the associated component parts. In this manner, it will be apparent that the upper shaft 6 of the sewing machine is stopped at a predetermined angular position after one complete rotation thereof by repeatedly pressing and releasing the foot controller of the sewing machine. With the structure and - function of this invention, it will be apparent that the operator of sewing machine is able to use both hands to deal with the sewn material during the basting operation, and that the operator of the sewing machine is able to move the sewn material placed under the machine needle with both hands, the machine needle being retained in an upper position spaced from the sewn material for a desired distance and to a desired direction for making basting stitches.
Figure 19 illustrates a further embodiment of the present invention, wherein a single pawl 111 is pivotally mounted on the belt wheel 5 in the same manner as the pawls 11 of Figure 7. The pawl 111 is normally biased against the periphery of the releasing cam member 109 and of the pawl wheel 110 by a compression spring 108 which is provided between the back of the pawl and the inner transverse peripheral wall 12 of the -~41~86Z
flange 13 of the belt wheel 5. The pawl 111 is, as in the case of pawls 11 in Figure 7, turned in the radially outward direction relative to the belt wheel 5 against the action of t~e spring by centrifugal force when the belt wheel is rotated in the direction as indicated by the arrow mark. According to this embodiment, the releasing cam member 109 and the pawl wheel 110 are provided with cam faces of recesses and projections all around the periphery thereof. Describiny the thread winding of the sewing machine, initially, the operating knob 91 of the switch device 98 is shifted to its upper or intermediate position wherein the connecting element 93 of-the knob contacts the ter-minals a and b or terminals b and c ready for driving the sew-ing machine at high speed or a lower speed, to sew ordinary continuous stitches. Simultaneously, the stopper lever 48 is turned in the countercloc~cwise direction against the action of the tension spring 78 and the end 75 of the lever 48 is drawn out of the path of rotation of the cam 24 of the stopper cam :
member 19 and of the projection 49 of the releasing cam member 46. The lever 97 in Figure 4 is then manually turned in a counter-clockwise direction against the action of the bistable spring 102 so as to press the gum wheel 105, which is rotatably mounted on lever 97, against the roulette face 106 of the flange 13 of -:~
the belt wheel 5, the double arm lever 95 is, at the same time, released and turned in a clockwise direction by the action of the spring 99, as shown in Figure 6 and the arm 96 of the lever 95 is brought into the path of rotation of the cam 24 of the stopper cam member 19. The stopper cam member 19 is, therefore, stopped when the foot controller is pressed and the shoulder 23 of the cam 24 engages the arm 96 of the double arm lever 95 during the rotation thereof. As the result, the roller 18 of the clutch device 9 is shifted to a wide space defined by the groove 14 of : : .:
:1~4886Z
the bushing 8 and the inner periphery 17 of the central bore 16 of the belt wheel 5 where the roller 8 is spaced from the inner periphery 17 o~ the bore 16. The belt wheel 5 is therefore rotated relative to the bushing 8 and the upper shaft 6, whereby a thread is wound on a bobbin, not shown in the drawings, if the latter is mounted on the vertical shaft of the gum wheel, as illustrated in Figures 2 and 3.
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Claims (21)
1. A sewing machine with an intermittent driving device comprising a machine housing, an upper shaft rotatably journalled in the machine housing, a belt wheel mounted on the upper shaft and rotatable relative to the upper shaft, clutch means provided between the upper shaft and the belt wheel and operable to connect and disconnect the belt wheel to and from the upper shaft, actuating means for actuating the clutch means to operate the same to a first position for connecting the belt wheel to the upper shaft and to a second position for disconnecting the belt wheel from the upper shaft, stopper means for engaging and stopping the actuating means, releasing means actuated to release the actuating means from the stopper means and means for actuating the releasing means to release the actuating means from the stopper means.
2. A sewing machine as claimed in claim 1 further compris-ing a foot controller for driving the belt wheel when it is pressed and for stopping the belt wheel when it is released, thereby driving the sewing machine intermittently with the repetition of pressing and releasing the foot controller.
3. A sewing machine as claimed in claim 1 further compris-ing operating switch means for shifting the stopper means between an effective position wherein the stopper means cooperates with the actuating means and a noneffective position wherein the stopper means is spaced from the actuating means.
4. A sewing machine as claimed in claims 1, 2 or 3, wherein the clutch means includes a bushing fixed on the upper shaft and formed with a groove and rotatably mounting the belt wheel therearound, and a roller located in a space defined by the groove and a part of the belt wheel and shiftable between a first position connecting the bushing to the belt wheel and a second position disconnecting the bushing from the belt wheel, thereby connecting and disconnecting the belt wheel to and from the upper shaft.
5. A sewing machine as claimed in claim 1, wherein the actuating means includes a cylindrical body connected to the bushing and rotated by the upper shaft, and provided with a transverse arm for shifting the roller of the clutch means between the first and second positions in the defined space and a cam provided on the outer periphery of the cylindrical body for cooperating with the stopper means.
6. A sewing machine as claimed in claims 1, 2 or 3, wherein the stopper means comprises a stopper lever shiftable between an effective position wherein the stopper lever engages the cam of the actuating means and stops the same and a non-effective position, wherein the stopper lever is spaced from the cam of the actuating means during the rotation thereof, and a tension spring usually urging the stopper lever to the effective position.
7. A sewing machine as claimed in claim 1, wherein the releasing means comprises a releasing cam means comprising a rotational body having a central bore and provided with a pro-jection for engaging the stopper lever and shifting the same to the noneffective position against the action of the tension spring, and further provided with a plurality of recesses.
8. A sewing machine as claimed in claim 1, wherein the releasing means comprises a releasing cam means and the means for actuating the releasing means comprises pawl means com-prising a plurality of pawl elements turnably mounted on the belt wheel, and a pawl wheel fixed to the actuating means and provided with a plurality of recesses which are aligned with recesses of the releasing cam means when the upper shaft is stopped, and wherein one of the pawl elements engages one of the aligned recesses as the belt wheel is stopped when the foot controller is released.
9. A sewing machine as claimed in claim 8, wherein the pawl engaging the aligned recess turns the rotational body relative to the actuating means to shift the stopper lever to the noneffective position against the tension spring as the belt wheel is rotated when the foot controller is pressed, thereby allowing the actuating means to shift the roller of the clutch means to the first position.
10. A sewing machine as claimed in claims 5 or 7, wherein the actuating means and the releasing means are stopped by the stopper lever located in the effective position after one complete rotation of the upper shaft, whereby the actuating means shift the roller of the clutch means to the second position, disconnecting the belt wheel from the upper shaft.
11. A sewing machine as claimed in claim 3, wherein the operating switch means comprises an operating knob, a cam element engaging the stopper lever and a connecting rod, one end of which is connected to the operating knob and the other end of which is connected to the cam element.
12. A sewing machine as claimed in claim 5, wherein the cylindrical body is provided with a pair of arcuated slots in a diametrically opposite relation, and is connected to the bushing by means of a pair of stepped screws passing through the slots respectively and screwed into the bushing, the cylindrical body adapted to be rotated by the upper shaft via the pair of stepped screws.
13. A sewing machine as claimed in claim 12, wherein the cylindrical body is normally urged in the direction of rotation by a spring one end of the spring being connected to the cylindri-cal body and a second end thereof being connected to the upper shaft.
14. A sewing machine as claimed in claims 12 or 13, wherein cushioning elements are provided in the arcuated slots respect-ively at the end parts thereof, the cushioning elements adapted to absorb an impact applied to the cylindrical body by the upper shaft via the stepped screws when the upper shaft is stopped.
15. A sewing machine as claimed in claims 5 or 7, wherein the cylindrical body has an axial collar with a cutout formed on the periphery thereof, and the rotational body has a pro-jection provided on the inner periphery of the central bore thereof, and wherein the rotational body is supported on the axial collar of the cylindrical body with a compression spring located in a space defined by the cutout and a part of the inner periphery of the central bore and by the projection of the rota-tional body, whereby the rotational body may be rotated by the cylindrical body via the compression spring.
16. A sewing machine as claimed in claim 8, wherein the recesses of the pawl wheel have faces respectively sloped in a radially outward direction of the pawl wheel, whereby the pawl in the aligned recesses of the actuating means and of the releasing cam means may be shifted out of the aligned recesses while rotating the releasing cam means as the belt wheel is rotated.
17. A sewing machine as claimed in claim 1, wherein the belt wheel is held on the bushing by means of a holder fixed to the bushing by means of a pair of screws, the holder pre-venting the belt wheel from being axially shifted on the bushing, the holder having a pair of flexible arms for releasably clamp-ing a central boss of a hand wheel on the upper shaft so that the hand wheel may be normally prevented from being shifted axially with respect to the upper shaft.
18. A sewing machine as claimed in claim 17, wherein an axial bore is provided on the central boss of the hand wheel and a head portion of one of the screws is inserted the bore, whereby the hand wheel is prevented from being turned relative to the upper shaft.
19. A sewing machine comprising:
a housing;
a needle on said housing displaceable between a down position engaging through a workpiece and an up position dis-engaged therefrom;
a drive shaft on said housing operatively connected to said needle;
a drive wheel on said shaft rotatable thereon relative to said shaft;
means including a clutch having one clutch member mounted on and jointly rotatable with said shaft, another clutch member operatively engageable between said one member and said wheel, and a control element operatively connected to said other member and displaceable between an engaged position for rotationally coupling said wheel and said shaft and a disengaged position for free relative rotation of said wheel and said shaft;
drive means connected to said wheel for rotating same and, in said engaged position of said clutch, for vertically reciprocating said needle between said up and down positions;
means including a formation on said shaft and a stopper on said housing displaceable between an operative position engageable with each other for stopping rotation of said shaft in a predetermined angular position corresponding to said up position and an inoperative position unengageable with each other;
means for displacing said control element from said engaged to said disengaged position on engagement of said stopper in said operative position with said formation, whereby said shaft can be arrested in said predetermined angular position and is substantially simultaneously rotationally uncoupled from said wheel, and means for substantially simultaneously displacing said control element into said engaged position and said stopper into said inoperative position.
a housing;
a needle on said housing displaceable between a down position engaging through a workpiece and an up position dis-engaged therefrom;
a drive shaft on said housing operatively connected to said needle;
a drive wheel on said shaft rotatable thereon relative to said shaft;
means including a clutch having one clutch member mounted on and jointly rotatable with said shaft, another clutch member operatively engageable between said one member and said wheel, and a control element operatively connected to said other member and displaceable between an engaged position for rotationally coupling said wheel and said shaft and a disengaged position for free relative rotation of said wheel and said shaft;
drive means connected to said wheel for rotating same and, in said engaged position of said clutch, for vertically reciprocating said needle between said up and down positions;
means including a formation on said shaft and a stopper on said housing displaceable between an operative position engageable with each other for stopping rotation of said shaft in a predetermined angular position corresponding to said up position and an inoperative position unengageable with each other;
means for displacing said control element from said engaged to said disengaged position on engagement of said stopper in said operative position with said formation, whereby said shaft can be arrested in said predetermined angular position and is substantially simultaneously rotationally uncoupled from said wheel, and means for substantially simultaneously displacing said control element into said engaged position and said stopper into said inoperative position.
20, A sewing machine as claimed in claim 19, wherein said one clutch member is a bushing rotationally fixed on said shaft at said wheel and said other member is a roller displaceable on said bushing between a position engaging both said bushing and said wheel and a position engaging only said bushing, said control element having a cutout receiving said cam roller,
21. A sewing machine comprising:
a housing, a needle on said housing displaceable between a down position engaging through a workpiece and an up position disengaged therefrom;
a drive shaft on said housing operatively connected to said needle;
a drive wheel on said shaft rotatable thereon relative to said shaft;
means including a clutch on said shaft between said shaft and said wheel and having a control element displace-able between an engaged position for rotationally coupling said wheel and said shaft and a disengaged position for free relative rotation of said wheel and said shaft, drive means connected to said wheel for rotating same and, in said engaged position of said clutch, for verti-cally reciprocating said needle between said up and down positions;
means including a formation on said shaft and a stopper on said housing displaceable between an operative position engageable with each other for stopping rotation of said shaft in a predetermined angular position corresponding to said up position and an inoperative position unengageable with each other:
means including a cam lobe operatively connected to said control element and operatively engageable with said stopper only in the operative position thereof for displacing said control element from said engaged to said disengaged position on engagement of said stopper in said operative position with said formation, said cam lobe being rotatable with said shaft and being relative to the normal direction of rotation of said shaft by said drive means ahead of said formation, whereby said stopper engages said cam lobe to disengage said control element and thereafter engages said formation to stop said shaft; and means for substantially simultaneously displacing said control element into said engaged position and said stopper into said inoperative position.
a housing, a needle on said housing displaceable between a down position engaging through a workpiece and an up position disengaged therefrom;
a drive shaft on said housing operatively connected to said needle;
a drive wheel on said shaft rotatable thereon relative to said shaft;
means including a clutch on said shaft between said shaft and said wheel and having a control element displace-able between an engaged position for rotationally coupling said wheel and said shaft and a disengaged position for free relative rotation of said wheel and said shaft, drive means connected to said wheel for rotating same and, in said engaged position of said clutch, for verti-cally reciprocating said needle between said up and down positions;
means including a formation on said shaft and a stopper on said housing displaceable between an operative position engageable with each other for stopping rotation of said shaft in a predetermined angular position corresponding to said up position and an inoperative position unengageable with each other:
means including a cam lobe operatively connected to said control element and operatively engageable with said stopper only in the operative position thereof for displacing said control element from said engaged to said disengaged position on engagement of said stopper in said operative position with said formation, said cam lobe being rotatable with said shaft and being relative to the normal direction of rotation of said shaft by said drive means ahead of said formation, whereby said stopper engages said cam lobe to disengage said control element and thereafter engages said formation to stop said shaft; and means for substantially simultaneously displacing said control element into said engaged position and said stopper into said inoperative position.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA76249112A CA1048862A (en) | 1976-03-26 | 1976-03-26 | Intermittent driving device for sewing machines |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA76249112A CA1048862A (en) | 1976-03-26 | 1976-03-26 | Intermittent driving device for sewing machines |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1048862A true CA1048862A (en) | 1979-02-20 |
Family
ID=4105583
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA76249112A Expired CA1048862A (en) | 1976-03-26 | 1976-03-26 | Intermittent driving device for sewing machines |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1048862A (en) |
-
1976
- 1976-03-26 CA CA76249112A patent/CA1048862A/en not_active Expired
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