JP4536508B2 - Needle bar drive - Google Patents

Description

  The present invention relates to a device for driving a needle bar of a sewing machine, and more particularly to a needle bar drive device having a mechanism for retracting a needle bar drive lever from a needle bar cam.

2. Description of the Related Art Conventionally, in a multi-head embroidery machine equipped with a plurality of sewing machines, a technique is known in which a needle bar of a sewing machine that is not sewn is arranged at a rest position higher than a normal top dead center position. For example, Patent Document 1 includes a needle bar drive lever that converts the rotation of the needle bar cam on the sewing machine spindle into the vertical movement of the needle bar, and the needle bar drive lever is attached in a direction to engage the needle bar cam with a spring. In addition, a device is described in which the needle bar is retracted from the needle bar cam by the actuator via the retracting cam and the needle bar is disposed at the rest position in conjunction with the needle bar driving lever.
JP-A-8-243282

  However, in this type of needle bar drive device, the needle bar may remain at a rest position or stop in the middle of lowering due to poor lubrication, dust adhesion or assembly errors. According to the conventional device, the needle bar drive lever is returned to the needle bar cam only by the urging force of the spring, so when the needle bar stops abnormally, the needle bar drive lever also stops at the retracted position or an irregular position during the return. To do. When the sewing machine is restarted in this state, there is a problem that the needle bar cam and the needle bar drive lever collide, and parts such as the cam engaging portion of the drive lever are damaged.

  The object of the present invention is to solve the above-mentioned problems and forcibly return the needle bar drive lever to the needle bar cam when the needle bar is returned from the rest position, thereby reliably preventing damage to the parts. It is to provide a driving device.

  In order to solve the above-described problems, a needle bar drive device according to the present invention includes a needle bar cam provided on a main shaft of a sewing machine, a needle bar drive lever that converts the rotation of the needle bar cam into the vertical movement of the needle bar, A spring that urges the needle bar drive lever in a direction to engage the needle bar cam, a retraction cam that retreats the needle bar drive lever from the needle bar cam against the urging force of the spring, and a needle bar that drives the retraction cam An actuator that rotates to an operating position that engages with the lever and a non-operating position that is away from the lever, and when the retracting cam rotates to the non-operating position, the needle bar drive lever is moved to the needle bar using the power of the actuator. And a return member to be returned to the cam.

Here, in order to operate the retracting cam and the return member with accurate timing, the following configuration can be preferably employed.
(1) The needle bar drive lever is swingably supported on the lever shaft, the retracting cam is fixed on the cam shaft, and the actuator is connected to both the lever shaft and the cam shaft via the power transmission mechanism. A return member that engages with the needle bar drive lever is fixed on the top.

Further, the following configuration can be preferably employed in preparation for a case where the needle bar is firmly held and the return member cannot return the needle bar drive lever even when the power of the actuator is used.
(2) A sensor for detecting the phase of the lever shaft or the cam shaft, and a control means for judging the step-out of the actuator based on the output of the sensor and stopping the main shaft of the sewing machine are provided.

  In the needle bar drive device of the present invention, when the needle bar is returned from the rest position, the retracting cam is separated from the needle bar drive lever, and instead, the return member is engaged with the needle bar drive lever. The return member applies the power of the actuator to the needle bar drive lever, biases the spring, and biases the needle bar drive lever toward the needle bar cam. At the same time, the return member causes the power of the actuator to act on the needle bar via the needle bar drive lever, and urges the needle bar downward. Therefore, even if the needle bar stops abnormally, the needle bar can be forcibly lowered and the needle bar drive lever can be forcibly returned to the needle bar cam to prevent damage to the parts when the sewing machine is restarted. it can.

  The needle bar drive device of this embodiment includes a needle bar cam 5 provided on the main shaft 4 of the sewing machine 1, a needle bar drive lever 43 that converts the rotation of the needle bar cam 5 into the vertical movement of the needle bar 14, and a needle. A spring 29 for biasing the bar drive lever 43 in a direction to engage with the needle bar cam 5; a retraction cam 65 for retracting the needle bar drive lever 43 from the needle bar cam 5 against the biasing force of the spring 29; A stepping motor (actuator) 48 that rotates the cam 65 to an operating position where the cam 65 is engaged with the needle bar drive lever 43 and a non-operating position apart from the lever 43 is provided.

  The stepping motor 48 is connected to both the cam shaft 63 and the lever shaft 41 through a power transmission mechanism. A retraction cam 65 is fixed to the cam shaft 63, and a needle bar drive lever 43 is swingably supported on the lever shaft 41, and a return member 70 that can engage with the lever 43 is fixed. When the retracting cam 65 is rotated to the non-operation position by the stepping motor 48, the return member 70 is configured to return the needle bar drive lever 43 to the needle bar cam 5 using the power of the stepping motor 48. ing.

  Hereinafter, an embodiment in which the present invention is embodied in a needle bar driving device for a chain stitch sewing machine will be described with reference to the drawings. As shown in FIGS. 1 and 2, a head 2 of the chain stitch sewing machine 1 is installed in a machine frame 3 of a multi-head embroidery machine. A main shaft 4 that is common to all head sewing machines passes through the upper portion of the head 2, and a needle bar cam 5, a nipple cam 6, and a presser foot cam 7 are disposed on the main shaft 4. A guide sleeve 8 is fixed to the lower part of the head 2, and a nipple 11 is attached to a lower end of a nipple base 9 inserted inside the head 2 via a holder 10.

  A rotary cylinder 12 is supported by a bearing 13 in the middle of the head 2, and a needle bar 14 is inserted inside the rotary cylinder 12 so as to be movable up and down. A needle 15 is attached to the lower end of the needle bar 14, and a needle bar base 16 is fixed to the upper part of the needle bar 14. A motor 17 is installed on the lower rear surface of the head 2, and a gear 19 on the motor shaft 18 is engaged with a gear 20 on the rotary cylinder 12. Then, the rotating cylinder 12 is driven by the motor 17, the needle bar base 16 and the nipple base 9 are rotated integrally therewith, and the directions of the needle 15 and the nipple 11 are controlled.

  On the right side of the needle bar 14, a guide bar 22 is erected on the head 2, and a needle bar elevating member 23 and a nipple elevating member 24 are slidably supported on the guide bar 22. The needle bar elevating member 23 is connected to the needle bar 14 via a claw 26 that fits into the annular groove 25 of the needle bar base 16. The nipple elevating member 24 is connected to the nipple 11 via a claw 28 that fits into the annular groove 27 of the nipple base 9. The needle bar elevating member 23 and the nipple elevating member 24 are urged downward by springs 29 and 30, respectively.

  On the left side of the needle bar 14, a cloth presser bar 32 is supported by the head 2 so as to be movable up and down, and is urged downward by a spring 33. A presser foot 35 for pressing a work cloth (not shown) to the needle plate 34 is attached to the lower end of the presser foot 32, and a cap 36 is attached to the upper end of the presser foot 32. An input piece 37 projects from the back surface of the cap 36, and a detent pin 39 that projects into the longitudinal groove 38 of the head 2 projects from the side surface.

  As shown in FIGS. 2 and 3, on the lower side of the main shaft 4, a lever shaft 41 is rotatably supported on the head 2 by a bearing 42. On the lever shaft 41, a needle bar drive lever 43, a nipple drive lever 44, and a presser foot drive lever 45 are supported in a swingable manner, and a gear 46 is provided on the left side of the presser foot drive lever 45 to drive the needle bar. A collar 47 is fixed on the right side of the lever 43. A stepping motor 48 is installed on the left side of the head 2, the gear 50 on the motor shaft 49 is engaged with the gear 46 on the lever shaft 41, and the phase of the lever shaft 41 is controlled by the stepping motor 48.

  An eccentric portion 51 is integrally formed in the middle of the lever shaft 41 in the axial direction, and the intermediate portion of the needle bar drive lever 43 is supported by the eccentric portion 51. Rollers 52 and 53 are provided at both front and rear ends of the needle bar drive lever 43, the rear roller 53 as a cam engaging portion is fitted into the cam groove 5 a of the needle bar cam 5, and the front roller 52 is connected via the link 54. It is connected to the needle bar elevating member 23 (see FIG. 4). Then, the rotation of the needle bar cam 5 is converted into the vertical movement of the needle bar 14 by the needle bar drive lever 43. Further, by controlling the phase of the eccentric portion 51 by the stepping motor 48, the swing center of the needle bar drive lever 43 can be changed and the stroke of the needle bar 14 can be adjusted.

  The nipple drive lever 44 includes a rear roller 58 fitted in the cam groove 6 a of the nipple cam 6 and a front roller 59 connected to the nipple elevating member 24, and the nipple cam 6 rotates by the nipple drive lever 44 to move the nipple 11 up and down. Is converted to The presser foot drive lever 45 includes a rear roller 60 that comes into contact with the cam surface 7a of the presser foot cam 7 and a front roller 61 that comes into contact with the input piece 37 of the presser foot 32 from below. The presser foot drive lever 45 converts the presser foot 35 into vertical motion.

  The needle bar cam 5, which is a groove cam, is formed with a notch 5 b for retracting the rear roller 53 of the needle bar drive lever 43. However, the needle bar drive lever 43 is urged in the direction in which the rear roller 53 engages with the cam groove 5a by the urging force of the spring 29 acting on the needle bar elevating member 23. Similarly, the nipple cam 6 is also provided with a notch (not shown), but the nipple drive lever 44 is attached in the direction in which the rear roller 58 is engaged with the cam groove 6a by the urging force of the spring 30 acting on the nipple elevating member 24. It is energized. The presser foot cam 7 is not provided with a notch, and the presser foot drive lever 45 is biased in the direction in which the rear roller 60 is engaged with the cam surface 7 a by the biasing force of the spring 33 acting on the presser foot 32.

As shown in FIGS. 3 and 4, a cam shaft 63 is rotatably supported on the head 2 below the lever shaft 41. A gear 64 that meshes with the gear 46 on the lever shaft 41 is fixed on the cam shaft 63, and the cam shaft 63 is rotated in a direction opposite to the lever shaft 41 by the stepping motor 48. On the camshaft 63, retracting cams 65, 66, 67 are fixed at positions corresponding to the drive levers 43, 44, 45, and the levers 43, 44, 45 are engaged with the retracting cams 65, 66, 67. Possible projecting pieces 43a, 44a, 45a are projected downward.

  As the cam shaft 63 rotates, the retracting cam 65 engages with the protruding piece 43a, swings the needle bar drive lever 43, and retracts the rear roller 43 from the cam groove 5a of the needle bar cam 5 through the notch 5b. Let At the same time, the retracting cam 66 swings the nipple driving lever 44, the rear roller 58 is retracted from the cam groove 6a of the nipple cam 6 through the notch, and the retracting cam 67 swings the presser foot driving lever 45, so that the rear roller 60 is clothed. The presser cam 7 is retracted from the cam surface 7a. A dog 68 is attached to the left end of the cam shaft 63, and a sensor 69 for detecting the phase of the cam shaft 63 is provided on the head 2.

  The collar 47 on the lever shaft 41 is formed with an arm 47a that protrudes toward the rear roller 53 side of the needle bar drive lever 43, and the arm 47a carries a return pin 70 that can be engaged with the needle bar drive lever 43 from below. Has been. The return pin 70 rotates around its axis integrally with the lever shaft 41, and when the retracting cam 65 is rotated to the operating position where it engages with the protrusion 43 a of the needle bar drive lever 43, the return pin 70 is moved to the needle. Move away from the rod drive lever 43. When the retracting cam 65 is rotated to the non-operating position away from the projecting piece 43a, the pin 70 is engaged with the needle bar drive lever 43 and the lever 43 is moved to the needle using the power of the stepping motor 48. The rear roller 53 is forcibly returned to the cam groove 5a by rotating toward the bar cam 5 side.

  Next, the operation of the needle bar driving device configured as described above will be described. During operation of the chain stitch sewing machine 1, the needle bar cam 5 rotates with the nipple cam 6 and the presser foot cam 7 as the main shaft 4 rotates, and the needle bar drive lever 43 is moved according to the cam shape of the needle bar cam 5. It swings between the solid line position and the chain line position. Then, the needle bar 14 moves up and down together with the needle bar elevating member 23, and the scissors needle 15 cooperates with a looper (not shown) below the needle plate 34 to form a stitch on the work cloth.

  When the needle bar 14 is stopped when the work cloth is replaced, the spindle 4 stops at a position where the notch 5b of the needle bar cam 5 faces the rear roller 53 of the needle bar drive lever 43 as shown in FIG. . In this state, the stepping motor 48 rotates, the cam shaft 63 rotates in the clockwise direction via the gears 50, 46, 64 (power transmission mechanism), and the retraction cam 65 moves to the protruding piece 43 a of the needle bar drive lever 43. It is arrange | positioned in the action position engaged with.

  As a result, the needle bar drive lever 43 swings counterclockwise at a large angle exceeding the swing range during sewing, and the rear roller 53 passes from the cam groove 5a through the notch 5b to the outside of the needle bar cam 5. The needle bar 14 moves up to a rest position higher than the top dead center position. Therefore, the interlocking of the main shaft 4 and the needle bar 14 is cut off, and another chain stitch sewing machine can be operated in a state where the chain stitch sewing machine 1 is stopped.

  When the needle bar 14 is returned from the rest position to the sewing position, as shown in FIG. 6, the cam shaft 63 rotates counterclockwise by the reverse rotation of the stepping motor 48, and the retracting cam 65 It is arranged at a non-acting position away from 43a. Then, the needle bar elevating member 23 is lowered by the urging force of the spring 29, and the needle bar drive lever 43 is swung clockwise. As a result, the rear roller 53 returns to the cam groove 5a of the needle bar cam 5, and the needle bar 14 returns to the sewing position.

  On the other hand, when the needle bar 14 is gripped due to poor oil supply or adhering dust, the return pin 70 urges the spring 29 to forcibly return the needle bar drive lever 43 and the needle bar 14. That is, when the retracting cam 65 rotates to the non-operating position, the collar 47 rotates clockwise with the lever shaft 41, the return pin 70 engages with the needle bar driving lever 43, and the stepping motor 48. Is exerted on the needle bar drive lever 43 to urge the rear roller 53 strongly toward the needle bar cam 5 side.

At the same time, the return pin 70 causes the power of the stepping motor 48 to act on the needle bar 14 via the drive lever 43 and the elevating member 23, and strongly urges the needle bar 14 downward. As a result, the gripping of the needle bar 14 is eliminated, the needle bar 14 is forcibly lowered, and the rear roller 53 is forcibly returned to the cam groove 5a. Therefore, when the chain stitch sewing machine 1 is restarted, collision between the needle bar cam 5 and the needle bar drive lever 43 can be avoided, and damage to the drive system components such as the rear roller 53 can be surely prevented.

  Further, according to the needle bar drive device of this embodiment, since the sensor 69 detects the phase of the cam shaft 63 in cooperation with the dog 68, the needle bar 14 is firmly held and the cam shaft 63 is locked. In this case, the controller (not shown) of the chain stitch sewing machine 1 determines the step-out of the stepping motor 48 based on the output of the sensor 69, immediately stops the spindle 4, and turns on an alarm lamp (not shown) on the head 2. Light up. Therefore, also in this case, it is possible to prevent the needle bar drive system parts including the return pin 70 from being damaged.

The present invention is not limited to the above-described embodiments. For example, as described below, the present invention can be appropriately modified and embodied without departing from the spirit of the invention.
(1) An electromagnetic solenoid or an air cylinder is used as an actuator for rotating the retracting cam 65.
(2) The dog 68 and the sensor 69 are provided on the lever shaft 41 side.
(3) The needle bar driving device of the present invention is applied to a lockstitch sewing machine.

It is a front view of the chain stitch sewing machine which shows one Example of this invention. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. It is operation | movement explanatory drawing of a needle bar drive lever. It is operation | movement explanatory drawing of a retracting cam. It is operation | movement explanatory drawing of a return member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chain stitch machine 2 Head 4 Main shaft 5 Needle bar cam 14 Needle bar 15 Needle bar 23 Needle bar raising / lowering member 29 Spring 41 Lever shaft 43 Needle bar drive lever 48 Stepping motor 53 Rear roller 63 Cam shaft 65 Retraction cam 69 Sensor 70 Restoration pin

Claims (1)

  The needle bar cam provided on the main shaft of the sewing machine, the needle bar drive lever that converts the rotation of the needle bar cam into the vertical movement of the needle bar, and the needle bar drive lever is biased in the direction of engagement with the needle bar cam. A spring, a retracting cam for retracting the needle bar drive lever from the needle bar cam against the biasing force of the spring, an operating position for engaging the retracting cam with the needle bar drive lever, and a non-operating position apart from the lever A needle bar comprising: a rotating actuator; and a return member for returning the needle bar drive lever to the needle bar cam using the power of the actuator when the retracting cam rotates to the non-operating position. Drive device.

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