JPH0433117Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention provides a cycle in which the main shaft of a sewing machine, which is in a high-speed driving state, is brought into a low-speed driving state several stitches before the end of one stitch, and then stopped. The present invention relates to a drive control device for a sewing machine.

[Conventional technology]

Conventionally, a drive control device for a cycle sewing machine, such as a hole sewing machine, operates a deceleration cam disposed on a rotary disk in order to operate a knife and forcibly stop the sewing machine needle at approximately top dead center without impact. The rotational speed of the motor is controlled, and the main shaft of the sewing machine, which is currently in a high-speed rotational state, is temporarily brought into a low-speed rotational state several stitches before the end of one sewing cycle, and then the stop cam acts on the cutoff device and the sewing machine needle returns to the above-mentioned position. The spindle is stopped at a fixed position so that it will come.

Further, the number of stitches required for one sewing cycle, that is, the number of stitches formed during one rotation of the rotary disk, is set by appropriately changing the gear ratio of the stitch number changing gear.

Therefore, the ratio of the number of stitches in the high-speed drive section and the low-speed drive section is constant, and when the number of stitches required for one sewing cycle increases by n times, the number of stitches in the low-speed drive section also increases by n times in proportion. Become.

[Problem to be solved by the invention] The drive control device of the conventional cycle sewing machine does not change the number of stitches required for the low-speed rotation drive period even if the number of stitches in the low-speed drive section changes due to a change in the stitch number change gear. Even though only a certain number of stitches are required to drop the knife and stop at a fixed position, the main shaft of the sewing machine is driven at a low speed according to the number of stitches that is proportional to the number of stitches required for one sewing cycle. The unnecessary low-speed time required for the sewing cycle was increased, reducing work efficiency.

Therefore, in this invention, regardless of the number of stitches required for one sewing cycle, the number of stitches during the low-speed rotation drive period is fixed, thereby shortening the time required for one sewing cycle to solve the above problem. be.

[Means for solving problems]

The drive control device for a cycle sewing machine according to this invention is configured to drive the cycle sewing machine by the first drive means based on the fixed number of stitches driven by the second drive means and the number of needles dropped within a predetermined period by the first drive means. The sewing machine is provided with a calculation means for calculating the number of stitches to be sewn, and a switching means for switching between the first drive means and the second drive means for driving the main shaft of the sewing machine based on the number of stitches.

〔Example〕

An embodiment of this invention will be explained based on FIGS. 1 to 3.

In the figure, 1 is a main shaft rotatably supported on a sewing machine frame 2, 3 is a drive clutch fixed to one end of this main shaft 1, and a rotation detection plate 4 is provided on a part of the circumference of this main shaft. . 5 is a rotation detection sensor for detecting this rotation detection plate 4; 6 is a drive pulley that is loosely fitted on the main shaft 1, and is adapted to come into contact with and separate from the drive clutch 3 by moving in the axial direction. . 7 is a worm gear fixed to the main shaft 1; 8 is a worm foil fixed to one end of a shaft 9 provided in a direction perpendicular to the main shaft 1; and meshes with the worm gear 7. 10
11 is a shaft provided parallel to the shaft 9; 12 is a first needle number changing gear removably mounted on one end of the shaft 11; The number of stitches changing gear 2 meshes with the gear 10. Reference numeral 13 denotes a rotary disk fixed to the other end of this shaft 11, which rotates once per sewing cycle.
It controls the amount of movement of the cloth, etc. By appropriately exchanging the needle number changing gears 12 and 10, the rotation ratio of the rotary disk 13 to the main shaft 1 is changed. 1
Reference numerals 4 and 15 indicate a speed switching cam and a stop cam respectively provided on the surface of the rotary disk 13; 16 is a hook pull-out lever whose central portion is pivotally supported by the sewing machine frame 2; A projection 17 that engages with the speed switching cam 14 and the stop cam 15
A hook portion 18 is provided at the other end and is pulled counterclockwise by a spring 49. Reference numeral 19 denotes a cutoff lever that is pivotally supported by a support 20 provided on the sewing machine frame 2, and is biased clockwise by a spring 21 stretched between the center portion of the cutoff lever 20 and the sewing machine frame 2. Reference numeral 22 denotes a protruding main shaft stopper which is rotatably supported at one end of the cutoff lever 19 via a pin 45. It engages with a cutoff cam 23 disposed on the drive clutch 3 to stop the main shaft 1 at a fixed position and stop the sewing machine needle at approximately the top dead center. Reference numeral 24 denotes an engaging protrusion provided on the other end of the cutoff lever 19, and has engaging portions 24a and 24b that engage with the hook portion 18 provided on one end of the hook removal lever 16. 25 is a switch push plate provided on the cutoff lever 19, and the protrusion 17
The deceleration detection switch 26 is activated depending on the engagement state of the deceleration detection switch 26 and the stop detection switch 27.
and ON/OFF control of the stop detection switch 27. Reference numeral 28 denotes an L-shaped activation link, and this elbow portion connects to a support 29 provided on the sewing machine frame 2.
It is rotatably supported by a shaft, and one end is connected to a starting pedal 31 via a rod 30. Reference numeral 32 denotes a protrusion provided at the other end of the starting link 28, and a protrusion 32 that moves the starting pedal 31 counterclockwise and interlocks therewith.
2, the cutoff lever 19 is rotated clockwise.
It is adapted to press a protrusion 33 provided at one end. 34 is a clutch lifter having a substantially J-shape, and an elbow portion thereof is pivotally supported by the support body 20. A guide pin 48 is provided at the end of the arm portion 34a.
It protrudes inward and enters the groove of the drive pulley 6 to enable rotation of the drive pulley 6, and also allows the drive pulley 6 to move left and right as the lifter 34 moves left and right. The arm portion 34b holds a pin 37 provided at the end of the arm portion 36 of the cutoff lever 19 together with a plate-shaped clutch lifter spring 35. 38 connects the drive pulley 6 to a belt 39
By switching the number of poles of the motor (first and second drive means) that is rotationally driven at
do. This motor may be one whose speed can be electrically controlled, such as an electromotor, a DC servo motor, or the like. 40 is an electromagnetic switch switching relay,
The number of poles of the motor 38 is changed by controlling the electromagnetic switches 41 and 42 ON/OFF. That is, when the electromagnetic switch switching relay 40 is energized, the contacts of the electromagnetic switch 41 are closed, so the circuit on the 8P side is closed and the motor 38 rotates at a low speed, and when the switching relay 40 is not energized, the contact of the electromagnetic switch 41 is closed. The contact of the switch 41 opens, the circuit on the 2P side closes, and the motor 38 rotates at high speed. The deceleration detection switch 26 and the electromagnetic switch switching relay 4
0 and electromagnetic switches 41 and 42 constitute a switching means. 43 is a microcomputer as a calculation means for calculating the number of stitches to be driven at high speed from a constant number of stitches driven at low speed by the motor 38 and the number of needles dropped within a predetermined period of time driven at high speed; This is a well-known device that has ROM, RAM, and input/output functions.

Next, the operation will be explained based on the flowchart of FIG.

It is now assumed that the sewing machine is in a stopped state and the various parts are as shown in FIG. That is,
Although the motor 38 is in a low speed drive state (for example, 900 rpm), the force of the spring 21 causes the cutoff lever 19 to
And since the drive pulley 6 is separated to the right from the drive clutch 3 via the clutch lifter 34,
The main shaft 1 is in a stopped state, and the main shaft stopper 22 is engaged with the cutoff cam 23, so that the needle bar is held at approximately the top dead center. In addition, the hook pull lever 16
The projection 17 is in contact with the stop cam 15.

(1) In this state, when the starting pedal 31 is operated and rotated counterclockwise, the starting link 28 is rotated clockwise by the rod 30, and the protrusion 32
is pressed by the protrusion 33. Then, the cutoff lever 19 is rotated counterclockwise, the switch push plate 25 moves away from the stop detection switch 27 and presses the low speed detection switch 26, and the stop detection switch 2
7 and turn off the low speed detection switch 26.
Turn off (STEP-1). At this time, the main shaft stopper 22 is released by the cutoff cam 23, the cutoff lever 19 is rotated counterclockwise, and the arm portion 34a of the clutch lifter 34 is rotated counterclockwise. As a result, the drive pulley 6 is pressed against the drive clutch 3, so the rotation of the motor 38 is transmitted to the drive clutch 3 via the belt 39 and the drive pulley 6, so the main shaft 1 rotates, and the rotary disk 13 rotates in conjunction. .

When the stop detection switch 27 is turned off,
The counter in RAM is reset (STEP-
2) When the low speed detection switch 26 is turned OFF, the electromagnetic switch switching relay 40 is turned OFF (STEP
-3). Then, the electromagnetic switch 41 is turned off and the electromagnetic switch 42 is turned on, and the motor 3
8 is driven at high speed by switching the number of poles from 8P to 2P. Therefore, the rotation detection plate 4 also rotates.

The rotation of the main shaft 1 rotates the rotary disk 13 via the worm gear 7, worm wheel 8, gears 10, 12, and shaft 11, and the hook release lever 1 is rotated.
6 is rotated counterclockwise by the spring 49, so that the protrusion 17 is separated from the stop cam 15. At this time, the hook portion 18 engages with the engaging portion 24a of the protrusion 24.

Then, the counter starts counting (adding) the pulse signals generated each time the rotation detection sensor 5 detects the rotation detection plate 4 (STEP-4).

(2) Next, return the starting pedal 31 to its original position. At this time, since the hook portion 18 and the engaging protrusion 24a remain engaged, sewing continues.

(3) Due to the high speed drive of the motor 38, sewing continues, and when the sewing is completed, the protrusion 17 of the hook release lever 16 moves to the speed switching cam 14.
It will get on top of. Then, the hook release lever 16 rotates slightly clockwise, and the hook portion 18 of the hook release lever 16 and the engagement protrusion 24 of the cutoff lever 19 are moved from the engagement position 24a to the 2
4b, and in response to this movement, the cutoff lever 19
rotates slightly clockwise. As a result, the switch push plate 25 moves away from the low speed detection switch 26 and turns it on.

(4) The low speed detection switch 26 is activated as described in (2) above.
When turned on (STEP-5), the count value L of the counter is input to the microcomputer 43, and the microcomputer 43 inputs the count value L,
In other words, from the number of needle drops before the low speed detection switch 26 is turned on, the total number of stitches L1 required for one sewing cycle and the remaining number of stitches are calculated based on formulas (a) and (b).
L2 is calculated (STEP-6 to STEP-7).

L1=L/(1-A)...(a) L2=L1×A...(b) However, A=θ/360°, θ is the angle that the cam 14 and the stop cam 15 make with respect to the shaft 11. be.

Then, the number of stitches L3 resulting from high-speed driving after the low-speed detection switch 26 is turned on is determined by equation (c).

L3=L2−L4 ……(c) However, L4 is the number of stitches due to low speed drive (= constant)
It is.

(5) Next, the number of stitches L3 is set in the counter in the RAM, and this counter continues to count (subtract) the pulse signal from the rotation detection sensor 5.
(STEP-9) Then, the number of stitches is counted by L3, that is, 1 is subtracted from L3 for each pulse, and when it becomes 0, the microcomputer 43 turns on the electromagnetic switch switching relay 40 (STEP-
11) Turn on the electromagnetic switch 41 and turn off the electromagnetic switch 42. Then, the motor 38
The number of poles of the motor is changed from 2P to 8P, and the motor 38
will rotate at a low speed.

(6) When the needle drop is performed by the number of stitches L4 in (3) above due to low-speed driving, that is, when the protrusion 17 moves to the stop cam 1
5, the hook portion 18 disengages from the engaging portion 24b of the engaging protrusion 24, and the cutoff lever 1
9 is rotated clockwise by the elastic force of the spring 21, the drive pulley 6 is disengaged from the drive clutch 3, and the stop detection switch 27 is activated.
Turns ON (STEP-12). Then, the main shaft stopper 22 engages with the cutoff cam 23, and the rotation of the main shaft 1 is stopped. At this time, the sewing machine needle stops at approximately the top dead center.

[Effect of idea]

With the configuration described above, this invention eliminates the need to adjust the deceleration driving time of the sewing machine each time in response to changes in the number of stitches required for one sewing cycle. Since the number can always be kept constant, there is an effect that the time required for one sewing cycle can be shortened.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of this invention, FIG. 2 is a perspective view showing a state in which the upper shaft and the main cam are connected, and FIG. 3 is a flow chart of the operation of this embodiment. 38... motor (first and second driving means),
43...Microcomputer (calculating means), 2
6... Switch, 40... Electromagnetic switch switching relay (switching means), 41, 42... Electromagnetic switch.

Claims (1)

[Claims for Utility Model Registration] A main shaft 1 that rotates in conjunction with the sewing machine motor, a rotating disc 13 that rotates at a reduced speed in conjunction with the main shaft, and a set of reducers that are replaceably arranged between the main shaft 1 and the rotating disc 13. In a cycle sewing machine which is equipped with gears 10 and 12 and is capable of changing the number of stitches in one sewing cycle by changing the gear ratio of the reduction gears 10 and 12, the sewing machine main shaft 1 is rotated at a high speed rotation that is a first rotation speed. a first driving means 38 that drives the sewing machine main shaft 1; a second driving means 38 that drives the sewing machine main shaft 1 at a second rotation speed that is slower than the first driving means; and a specific rotation angle of the rotary disk 13. a low speed detection means 26 that generates a low speed signal in relation to the second drive means; a setting means that presets the set number of stitches to be driven by the second drive means at a low speed; a counter that counts the number of stitches from the number of rotations of the main shaft; Calculating means 43 for calculating the number of stitches to be driven in high speed rotation by the first driving means from the counter value of the number of stitches from start to generation of the low speed signal and the set number of stitches;
and, when the number of stitches counted matches the number of stitches to be driven by the first drive means from the calculated set number of stitches during one sewing cycle, the sewing machine is switched from the first drive means to the second drive means. A drive control device for a cycle sewing machine, comprising a switching means for switching to.