JPS6234534Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to an improvement of a cloth feeding device for a blind stitch sewing machine.

In conventional blind stitch sewing machines, when changing the amount of cloth fed by a feed dog attached to a feed table, the amount of eccentricity of an eccentric cam that swings the feed table using the frame body as a fulcrum is adjusted. In this case, first stop the operation of the sewing machine, then operate the pushbutton, turn the pulley by hand to change the angle, and change the amount of eccentricity of the eccentric crank to change the desired feed amount, or Remove the cover containing the eccentric cam, loosen the set screw of the eccentric cam with a screwdriver, etc., turn the pulley by hand to change its angle, and when the desired feed amount is reached, tighten the set screw of the eccentric cam again with a screwdriver, etc. This required complicated operations.

By the way, when sewing the pocket with a blindstitch sewing machine, the only way to sew the beginning and end of the step-stitched part of the pocket is to sew at a constant feed rate. In order to prevent it from cutting and fraying, this part is hand-sewn in a separate process to bar-tack, or a special blind-stitch bar-tack sewing machine called a dotsuking sewing machine is used to perform reinforcement sewing work. It was on. However, these methods not only significantly hinder work efficiency, but also
I couldn't get beautiful seams.

In addition, since blind stitch sewing machines use chain stitch, if the last stitch frays, the entire stitch frays, but conventionally the needle is stopped at the top dead center to prevent the needle from breaking. After that, the fabric was pulled forward to cut the thread, and when the thread was cut, the sewing was completed, and no special tacking was done.

However, with this method, when the fabric is pulled, the seam threads are pulled, causing the beautiful seams to shrink.
This not only reduces the value of the product, but also causes the threads to fray.

For this reason, after cutting the thread, it is necessary to manually tie the end of the thread and tie a knot, or at the end of sewing, use the pedal to remove the presser foot that is in pressure contact with the throat plate. By separating them and reducing the amount of cloth fed, the stitches are sewn in close overlaps to prevent fraying. However, in the former case, the work efficiency is low because it is done manually, and in the latter case, the presser foot is moved away from the throat plate to perform the tacking, so the fabric is not held stably, and the thickness and material of the fabric Due to differences in feed rate and operator handling, it has been impossible to achieve consistent and perfect locking stitches.

In the present invention, the tip of the front-rear feed rod that provides cloth-feeding motion to the cloth feed table is rotatably attached to the front-rear feed adjustment crank, and the front-rear feed adjustment crank is slid up and down along the feed table support rod. The above problem is solved by changing the amplitude of the swinging movement of the feed table support rod and changing the cloth feeding stroke of the cloth feed table. The object of the present invention is to provide a cloth feeding device for a sewing machine that can steplessly change the stroke of cloth feeding from a cloth feeding state to tacking stitching.

Hereinafter, the present invention will be explained based on the drawings.

1 to 11 show a first embodiment of the present invention, in which reference numeral 51 is an upper shaft, 52 is an eccentric cam, and 53 is an adjustment eccentric cam. These eccentric cams 52 and adjustment eccentric cams 53 are well-known, and when the upper shaft 51 rotates, a screw 5 is attached to the free end.
A cloth feed stand 56 to which a feed dog 55 is fixed by 4
It is designed to give a rocking motion to the

That is, an adjustment eccentric cam 53 is slidably fitted into a U-shaped frame 56a formed at the root end of the cloth feed table 56 via an eccentric cam 52 that receives rotation of the upper shaft 51. It is designed to give vertical movement to the feed dog 55. In addition, the cloth feed table 56
A feeder support pin 58 is fixed approximately midway between the free end and the root end with a screw 59, and a feeder support rod 57 is rotatably attached to the feeder support pin 58. There is. A support rod pin 63 is fixed to the lower end of the feeder support rod 57 with a screw 64, and a bearing bush 62 press-fitted into the frame body 60 and fixed with a screw 61 has the support rod pin 63 fixed to the lower end of the feeder support rod 57. A rod pin 63 is rotatably attached. Therefore, the cloth feed table 56 is connected to the support rod pin 6.
3 as a fulcrum and swings relative to the frame body 60.

On the other hand, the back and forth feed rod 65 installed in parallel with the cloth feed table 56 has its base end rotatably fitted into the adjustment eccentric cam 53, and a boss portion 65a at its tip that adjusts the back and forth feed. crank 6
It is rotatably attached to a longitudinal feed rod pin 68 fixed to the upper end of the rod 7 with a screw 66. The crankshaft 67b of the longitudinal feed adjustment crank 67 is connected to a support rod pin 63 on a longitudinal feed adjustment arm 71 fixed to the transmission shaft 69 by a screw 70.
It is rotatably mounted approximately in line with the center of the Then, the crankshaft 6 is tightened by the screw 73.
A collar 72 fixed to 7b restricts movement of the longitudinal feed adjustment crank 67 in the axial direction. Furthermore, the above-mentioned longitudinal feed adjustment crank 6
A slider 74 rotatably attached to the tip of the feed base support pin 58 is slidably fitted into the groove 67a formed in the groove 67a.

On the other hand, the transmission shaft 69 has one end supported by the frame body 60 and the other end rotatably supported by a shaft support plate 91 fixed to the frame body 60 with screws 90. . An operating lever 75 is fixed to one side of the shaft support plate 91 of the transmission shaft 69 with a screw 92. That is, as the operating lever 75 rotates, the transmission shaft 69 rotates, and the longitudinal feed adjustment crank 67 is moved to the slider 74 via the longitudinal feed adjustment arm 71 in accordance with the rotation angle of the transmission shaft 69. It is designed to slide up and down along the line. Also, on the side of the shaft support plate 91,
An adjustment block 94 is secured by a dowel pin 93. The adjustment block 94 and the operating lever 7
By sandwiching the shaft support plate 91 between the
It is configured to restrict movement of the transmission shaft 69 in the axial direction.

Operation lever 7 screwed to the transmission shaft 69
A mounting hole 75a is drilled in the free end of 5 for mounting an operating rod (not shown) connected to a foot pedal, an air cylinder, a solenoid (not shown), or the like. Further, a bulging portion formed by bulging the upper end surface of the operating lever 75 is formed near the mounting hole 75a, and a hole 75b is bored in this bulging portion. A tension coil spring 95 is attached to the hole 75b by being engaged with a pin 96 supported by the frame body 60 above the operating lever 75.

Further, a protrusion 75d having a substantially elliptical elongated hole 75c is formed in the center of the operating lever 75, and a stop pin 97 fixed to the frame body 60 is inserted into the elongated hole 75c. That is, the rotation angle of the operating lever 75 is determined by the long hole 75c.
regulated by the length of the Therefore, the elongated hole 75c
The length is set so that the longitudinal feed adjustment crank 67 can slide up and down along the slider 74 with its groove 67a by rotation of the operating lever 75.

The adjusting block 94, which is formed of a thick plate with an elliptical planar shape on both sides, has adjusting screws 10 fitted with coil springs 98 and 99 to prevent loosening on both sides.
0.101 is screwed through. At the tips of the adjusting screws 100 and 101, a stop plate 102 is attached to the frame body 60, which abuts the respective screw ends.
is fixed.

Next, the operation of the cloth feeding device of the first embodiment will be explained.

First, when the upper shaft 51 is rotated, the cloth feed table 56
The feed dog 55 moves up and down using the support rod pin 63 of the feed table support rod 57 as a fulcrum as the eccentric cam 52 and the adjustment eccentric cam 53 rotate.
Further, the feed table support rod 57 is swung by the back and forth feed rod 65, and the feed dog 55 is given back and forth motion. Therefore, the feed dog 55 feeds the cloth by drawing a substantially elliptical circulation locus B by combining these vertical and longitudinal movements.

In this case, in the normal cloth feeding state, that is, in the state in which the operating lever 75 is not operated, the longitudinal feeding adjustment crank 67 is rotated as shown in FIGS.
Since the axes of the crankshaft 67b and the support rod pin 63 almost coincide, the longitudinal feed adjustment crank 67 and the feed base support rod 57 are moved around the crankshaft 67b and the support rod pin 63 as fulcrums, respectively, by the longitudinal feed rod 65. and perform a rocking motion with the same amplitude.

Therefore, the feed dog 55 attached to the cloth feed table 56 draws a circulation trajectory B shown by a broken line, as shown in FIG. Stroke BS of this circulation trajectory B
and the height BH are the eccentric cam 52 and the adjustable eccentric cam 53.
Determined by the amount of eccentricity. If it is assumed that the eccentricity of the eccentric cam 52 and the adjustment eccentric cam 53 is constant, the stroke BS will be maximum in the normal cloth feeding state when the operating lever 75 is not operated.

Next, the operating lever 75 is lowered in the direction of arrow 0 shown in FIG. figure). Then, the feed base support rod 57 is
A rocking motion with an amplitude of approximately 1/2 is performed using the crankshaft 67b as a fulcrum. The swinging motion, that is, the back and forth movement of the feed table support rod 57 is transmitted to the cloth feed table 57, so that the feed dog 24 is moved as shown in FIG.
The height BH of the circulation trajectory B hardly changes, but the stroke BS' changes by about 1/2. However, it is assumed that the eccentricity of the eccentric cam 52 and the adjusting eccentric cam 53 does not change.

Furthermore, the operating lever 75 is lowered to raise the longitudinal feed adjustment crank 67, and the axes of the slider 74 and the crankshaft 67b are aligned (FIG. 9).
Then, the crankshaft 67b becomes a fixed point. Therefore, the feed base support rod 57 via the slider 74
does not swing, so the height BH of the circulation path B of the feed dog 55 hardly changes as shown in Fig. 10, but the stroke BS'' becomes almost zero. In this state, the fabric is almost Since it is stopped without being fed, the sewing thread will not easily come undone if you perform overlapping sewing.

In addition, by adjusting the adjustment screws 100 and 101, the rotation range of the operation lever 75, that is, the transmission shaft 69
By regulating the rotation range of the operating lever 75, the feed stroke can be adjusted steplessly from a predetermined length BS to almost zero BS''.In other words, if the cloth feed stroke is set in advance, the
The desired cloth feed amount can be obtained by simply operating the . Therefore, there is no need to stop the operation of the sewing machine and perform manual sewing again, or to perform reinforcing sewing work using a darting sewing machine. For example, FIG. 11 shows the sewing state of the pocket on the back side of the fabric sewn using the fabric feeding device of the above embodiment. The threads are finely stitched to ensure that the threads do not come undone.

Note that in order to return to the normal cloth feeding state, the force applied to the operating lever 75 may be released. That is, the tension coil spring 95 causes the operating lever 75 to rotate in the direction opposite to the arrow 0 shown in FIG. Then, as the operating lever 75 rotates, the transmission shaft 69 rotates, and the forward/backward feed adjustment crank 6
Since the crankshaft 67b of No. 7 returns to the center of the support rod pin 63, the feed dog 55 performs a normal cloth feeding movement.

Next, the second embodiment of the present invention will be explained from FIG. 12 to the first embodiment.
This will be explained based on FIG. Note that in this second embodiment, configurations that are different from those in the first embodiment will be described, and descriptions of the same configurations will be omitted.

A U-shaped frame 85a formed at the root end of the cloth feed table 85 is fitted with a feed table vertical sliding assembly 84 so as to be slidable in the front-rear direction. A feed table vertical eccentric cam 83 fixed to the upper shaft 51 with a screw 82 is rotatably fitted into the feed table vertical sliding assembly 84 .

That is, the U-shaped frame 85a is configured to move up and down by twice the amount of eccentricity of the feed table vertical eccentric cam 83. In addition, the eccentric cam 86 and the back-and-forth feed eccentric cam 87 provided on the upper shaft 51 are shortened axial lengths of the eccentric cam 52 and the adjustment eccentric cam 53 shown in the first embodiment, and are It has a configuration independent of the upper and lower eccentric cams 83. In other words, the back and forth feed rod 65 is designed to move back and forth independently of the up and down movement of the frame 85a.

Next, the operation of the cloth feeding device of this second embodiment will be explained.

First, when the upper shaft 51 is rotated, the cloth feed table 56
The feed dog 55 moves up and down using the support rod pin 63 as a fulcrum by the rotation of the feed table vertical eccentric cam 83. In addition, the above-mentioned feed dog 55
gives back and forth motion to. Therefore, the feed dog 55 feeds the cloth by drawing a substantially elliptical circulation locus by combining these vertical movements and back-and-forth movements.

If it is desired to change the amount of cloth feed, the desired stroke can be set in advance by changing the amount of eccentricity of the back and forth feed eccentric cam 87. Therefore, normal cloth feeding is performed with a stroke S that is preset according to the eccentricity of the longitudinal feeding eccentric cam 87. On the other hand, when performing tacking, the operation lever 75 may be operated in the same manner as in the first embodiment to change the cloth feeding stroke.

In this case, in the first embodiment, when the eccentricity of the adjustment eccentric cam 53 is adjusted, as shown in FIG. 14, not only the cloth feeding stroke _S1 changes to _S2 , but also the height changes from _H1 to H changes to ₂ , but the second
In the embodiment, even if the amount of eccentricity of the front-rear feed eccentric cam 87 is changed, the amount of eccentricity of the feed table vertical eccentric cam 83 does not change. That is, as shown in FIG. 15, the stroke S ₁ of the feed dog 55 only changes to S ₂ , and the height H ₁ hardly changes. Therefore, even if the cloth feeding stroke is changed by adjusting the eccentricity of the back-and-forth feeding eccentric cam 87, the feeding dog 55 can always feed the cloth reliably. Further, in a frame 85a formed at the root end of the cloth feed table 85, a feed table vertical eccentric crank 83 is attached to the feed table vertical sliding body 85a.
4, the durability of the sliding part is high.

Note that the other effects of the second embodiment are the same as those of the first embodiment, so their explanation will be omitted.

Furthermore, although the first and second embodiments have been described with respect to the cloth feeding device of a blind stitch sewing machine, it is of course possible to use the cloth feeding device with other sewing machines.

As mentioned above, in the present invention, the tip of the longitudinal feed rod is rotatably attached to the longitudinal feed adjustment crank, and the longitudinal feed adjustment crank is slid up and down with respect to the feed bar support rod. The cloth feeding stroke of the cloth feed table is changed by changing the amplitude of the swinging motion of the rod. Therefore, the cloth feed stroke can be adjusted steplessly from a predetermined amount to almost zero, and there is no need to stop the sewing machine and use hand sewing or darting sewing machines, resulting in improved work efficiency. Not only can efficiency be improved, but also beautiful seams can be obtained.
Furthermore, by adjusting the cloth feed stroke to zero, it is possible to perform almost complete tacking without stopping the operation of the sewing machine, thereby reliably preventing thread fraying.

[Brief explanation of the drawing]

Figures 1 to 11 show the first embodiment of the present invention. Figure 1 is a three-dimensional perspective view showing the cloth feeding device of the present invention, and Figure 2 is a cloth feeding device installed in a blind stitch sewing machine. FIG. 3 is a front view of FIG. 2, FIG. 4 is a side view showing the main parts of the cloth feeder, and FIGS. 5, 7, and 9 are views of the cloth feeder. Fig. 6, Fig. 8 and Fig. 10 are circulation locus diagrams showing the movement state of the feed dog, and Fig. 11 is a reference drawing showing the sewing state according to the present invention. 12 to 15 show a second embodiment of the present invention, in which FIG. 12 is a plan view showing the main parts, and FIG. 13 is a side view showing the main parts of the cloth feed table. FIG. 14 is a circulation locus diagram showing the movement state of the conventional feed dog, and FIG. 15 is a circulation locus diagram of the feed dog according to the second embodiment. 51... Upper shaft, 52... Eccentric cam, 53... Adjustment eccentric cam, 55... Feed dog, 56... Fabric feed stand, 57... Feed stand support rod, 60... Frame body, 63... Support Rod pin, 65... Longitudinal feed rod, 67... Longitudinal feed adjustment crank, 6
9...Transmission shaft, 83...Feed table vertical eccentric cam, 8
5...Cloth feed table, 86...Eccentric cam, 87...Back and forth feed eccentric cam.

Claims (1)

[Scope of utility model registration request] A cloth feed table with a feed dog at its free end has its root end fitted into an eccentric cam on the upper shaft, and its intermediate portion is pivotally supported by a feed table support rod that swings around a support rod pin as a fulcrum. The feeder support rod is attached to the feeder support rod and slides along the feeder support rod by rotation of a transmission shaft rotatably supported by the frame body, thereby changing the swing amplitude of the feeder support rod. A front and rear feed adjustment crank is provided that changes the cloth feed stroke of the cloth feed table by changing the
The fore-and-aft feed adjustment crank is provided with a fore-and-aft feed rod whose base end engages with the eccentric cam of the upper shaft and whose tip end is rotatably attached to provide back-and-forth movement to the feed bar. A cloth feeding device in a sewing machine characterized by the following.