JPS5946192B2 - Cycle sewing machine knot forming mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cycle sewing machine for performing scheduled cycle stitches on a workpiece using a lock stitch in which an upper thread and a lower thread are knotted. In order to prevent unraveling, the needle drop is performed twice in the same place on the workpiece at the end of cycle sewing to form pitch stitches twice in a row, so that the upper thread and bobbin thread become tighter. The present invention relates to a knot forming mechanism for forming tied knots.

It is well known that in this type of sewing machine, the above-mentioned knot is formed by dropping the needle twice in the same place on the workpiece in the final part of cycle stitching and forming pitch stitches twice in succession. In general, in a lockstitch sewing machine, when the feed direction of the workpiece is in the forward direction, the bobbin thread that connects the bottom surface of the workpiece and the hook is positioned on one side of the needle path to form a perfect stitch. , when moving in the opposite direction, it is located on the other side to form a pitch stitch (Special Publications Publication No. 5)
2-39325) is also well known.

Conventionally, in this type of sewing machine, when forming the above-mentioned knot, the needle was simply dropped into the same place on the workpiece twice in a row, so the feeding direction of the workpiece before the first needle drop was correct. In the case of the direction, a part-eft stitch is formed by the needle entry, and at the time of the second needle entry, since the material has not been fed from the first needle entry, the second needle entry This makes it very unstable whether a perfect or hit stitch is formed, and therefore the pitch stitch required to form a knot cannot be reliably formed twice in succession. , it was not always possible to form a knot reliably.

This invention provides a control mechanism for forcibly controlling the bobbin thread connected to the lower surface of the workpiece and the hook to a position on the side where a hit stitch is formed at least before the second needle drop. The object of the present invention is to provide a cycle sewing machine that can reliably form hit stitches and reliably form knots.

Embodiments of the present invention will be described below with reference to the drawings.

In the illustrated sewing machine 1, when the operating lever 2 is rotated clockwise around the step screw 3, the control lever 4 moves to the operating position and the sewing machine 1 is driven, and the operating shaft 5 rotates due to the drive. The operating lever 2 is maintained at the rotational position by the outer peripheral surface of the control cam 6 disposed in the control lever 4.
is maintained in the operating position, and after forming a certain cycle stitch, the step portion 6a of the control cam 6 rotates once and returns to the position facing the operating lever 2. This is a well-known cycle sewing machine in which the control lever 4 moves back to the non-operating position and stops the sewing machine 1 as the sewing machine 1 returns to its counterclockwise rotation.

The operating shaft 5 is a disc-shaped feed cam with a cam groove 7a formed on the front surface for horizontal feeding of a holding mechanism to be described later, and a cam groove 7b for longitudinal feeding (left-right direction in Fig. 1-2) formed on the back surface. 7
is fixed, and a bearing 8 is disposed close to the feed cam 7 on the rear upper surface of the bed portion 1a of the sewing machine 1.

As shown in FIG. 5.6, this bearing 8 is provided with a horizontal bearing hole 8a and a cylindrical shaft portion 8b on one end surface. The middle part of the L-shaped first rotating arm 9 is rotatably fitted and supported, and is provided with a fitting pin 9a that fits into the cam groove 7a of No. 7.
A support shaft 10 is fitted and supported within the bearing 8 so as to be rotatable and with its tip protruding from the other end surface of the bearing 8.

The distal end of the support shaft 10 is provided in a radial direction from the center of the base (
The center of the base of the second rotating arm 11, which has a guide hole 11a in the vertical direction) and an arm 11c extending in the horizontal direction, is fitted and fixed with a screw 12. Fitting pin 11a that fits into cam groove 7b of cam 7
will be established.

As shown in Figures 1 and 2.4, a needle plate 15 provided with a needle drop hole 15a for the needle 14 of the needle bar 13 disposed in the sewing machine jaw is disposed on the upper surface of the sewing machine bed 1a. A holding mechanism 16 is arranged on the top surface of the holding mechanism 15 .

This holding mechanism 16 is a base plate that is slidable along the upper surface of the throat plate 15 in the front-rear direction (X direction in FIG. 1) and the left-right direction (Y direction), and has a receiving plate 17 (see FIG. 4) at the tip. 18 and
The rear end of the substrate 18 is placed on the substrate 18 from the horizontal axis 19a.
A pair of holding arms 19 are disposed opposite to each other on the upper surface of the receiving plate 17 for holding a button to be sewn onto the fabric to be sewn at the tip thereof located directly below the sewing machine jaw. A guide pin 21 is vertically disposed on the middle part of the upper and lower plates 20, and the tip of the guide pin 21 is placed on the lower surface of the sewing machine arm 1b to allow movement back and forth and left and right. The spring holder has a piece 22 provided with a guide hole 22a for fitting into the spring holder, and this spring holder has a spring between the lower surface of the piece 22 and the upper surface of the upper and lower plates 20 to always spring the upper and lower plates 20 downward. 23 are arranged around the guide pit 21.

Further, on the upper surface of the rear end of the upper and lower plates 20, a passive piece 24 is provided which is interlocked with an elevating mechanism (not shown) disposed on the sewing machine arm.
The upper end of the passive piece 24 is moved rearward by the operation of the elevating mechanism, and this movement causes the upper and lower plates 20 to move along the horizontal axis against the elastic force of the spring 23. 17 in a clockwise direction, and a holding arm 19 at the tip thereof rises from the upper surface of the receiving plate 17.

A guide pin 25 is disposed in the middle of the throat plate 15 and is capable of reciprocating from side to side in conjunction with a left and right feed mechanism (not shown) disposed in the sewing machine bed part a. A guide hole 26 long in the front-rear direction is provided for loosely fitting the guide pin 25 therein.

The left-right feeding mechanism is linked to the other end of the first rotating arm 9, and the rotation of the rotating arm 9 causes the guide pin 25 to move horizontally to the left or right. This horizontal movement causes the base plate 18 to slide left and right (in the Y direction in FIG. 1) along the upper surface of the throat plate 15.

As shown in FIGS. 4 and 5, a movable body 27 is arranged so as to be movable in the front and back direction behind the sewing machine bed surface, and the rear end of the base plate 18 is attached to the upper surface of the movable body 27 by means of step screws 28 along the vertical axis. A bearing 30 that supports the ball joint shaft 29 is disposed on the upper surface of the base plate 18 above the connecting portion.

Further, at the rear end portion of the sewing machine arm portion 1b, the upper end of a power transmission body 31, which has a vertical guide hole 31a corresponding to the guide hole 11a of the second rotating arm 11 in the intermediate portion, is connected to the upper end of the transmission body 31 by a support shaft 32. It is supported so as to be rotatable about a horizontal axis perpendicular to the forward and backward feeding direction and to face the guide portion 11b of the second rotating arm 11, and a guide pin 29a provided on the ball joint shaft 29 is attached at the lower end. The guide hole 31a is loosely fitted so as to be movable in the vertical direction, and is formed in the guide hole 31a on the side facing the second rotating arm 11.
A step portion 31b is provided around the periphery.

A branch piece 33 is fixed to the rear end surface of the transmission body 31 with a screw 34, and this branch piece 33 has a lever piece 35a and a locking piece 35b at its tip, and a horizontally long guide hole 35c in the middle part. The rear end of the adjustment lever 35 made of an elastic plate is connected to the stepped screw 3.
6, it is supported rotatably about a horizontal axis parallel to the support shaft 32.

A square piece 37 having a horizontal axis hole in the center is loosely fitted into the guide hole 11a of the second rotating arm 11 so as to be movable up and down along the guide hole 11a. is right half 3
The tip of the right half 38a of the stepped interlocking pin 38, in which 8a has a large diameter and the left half 38b has a small diameter, is rotatably fitted loosely, and the right half 38a, which has a large diameter, is connected to the adjustment lever 35.
The left half 38b is formed by horizontally penetrating the inside of the guide hole 35c and fitting the stepped portions of the right half 38a and the left half 38b into the stepped portion 31b provided around the guide hole 31 of the transmission body 31. It fits horizontally into the guide hole 31a of the transmission body 31.

A threaded portion 38c protruding from the guide hole 31a is formed around the tip of the left half portion 38b of the interlocking pin 38, and a cylindrical intermediate piece having a diameter larger than the width of the guide hole 31a is formed in the threaded portion 38c. 39 is loosely fitted, and then a nut 40 is screwed onto the tip of the threaded portion 38c protruding from the rear end surface of the intermediate piece 39 and tightened. As a result, the interlocking pin 38 is tightened to the transmission body 31, and the nut 40 is loosened. If the adjustment lever 35 is rotated in this movable state, the interlocking pin is guided by the guide hole 35c. 38 can be adjusted upward or downward, and as the interlocking pin 38 moves, the square piece 37 also moves within the guide hole 11a of the second rotating arm 11.

Further, the transmission body 31 is formed into an arc shape centered on the rotation center of the adjustment lever 35, and the locking piece 35b of the adjustment lever 35 is fitted and locked on the outer periphery of the transmission body 31, so that the adjustment lever 35 can be positioned. That is, a plurality of positioning locking holes 41a are provided for positioning the interlocking pin 38, and an instruction plate 41 having an instruction mark consisting of a number or the like is arranged in each of the locking holes 41a.

As shown in FIGS. 1 and 2, a support piece 42 is disposed on the bearing 8, and a retaining pin 43a that can be engaged with the outer peripheral surface of the feed cam 7 is provided at the upper end of the support piece 42. The intermediate portion of the moving lever 43 is rotatable by a shaft 44 about a horizontal axis parallel to the operating shaft 5, and is normally rotated in a direction in which the retaining pin 43a is pressed against the outer circumferential surface of the feed cam 7 (clockwise in FIG. 1). ) is supported by applying an elastic force (not shown) to the sewing machine bed 1a, and as shown in FIG.
Two elongated holes 46a and 46b, which are long in the front-rear direction, are provided in the front half of the throat plate 15 to enter into the lower surface of the throat plate 15 and loosely fit into the step portions of two step screws 45 and 45 arranged in the front-rear direction on the lower surface of the throat plate 15. , and also in the rear half, there is a long hole 46b in the front-rear direction that loosely fits into the guide pin 47 set up on the bed surface.
A connecting link 46 provided with is disposed so as to be movable in the front-rear direction, and the rear end of the interlocking link 46 is rotatably connected to the lower end of the rotating lever 43.

On the lower surface of the throat plate 15, an intermediate portion of the rotation link 48 is rotatably supported around a vertical axis, and one end of the rotation link 48 is rotatably connected to the front end of the connection link 46. In addition, in the vicinity of the needle drop hole 15a, the base of a bobbin thread catcher 49, which has a forked hook portion 49a at its tip for capturing the bobbin thread, is supported so as to be rotatable about a vertical axis. , this lower thread catcher 49 and the other end of the rotation link 48 are connected by an intermediate link 50.

On the other hand, on the outer peripheral surface of the feed cam 7, there are
A chevron-shaped cam 51 is arranged to engage with the engagement pin 43a at the upper end of the rotary lever 43 and rotate the rotary lever 43 counterclockwise in FIG. 1 against the elastic force.

The counterclockwise rotation of the rotary lever 43 causes the connecting link 48 to move rearward (to the right in FIG. 3), and
The rotation link 48 rotates counterclockwise, and the intermediate link 50
The bobbin thread catcher 49 rotates counterclockwise via the hook 49a at the tip thereof, and the hook portion 49a moves forward of the needle droplet 15a from a position to the left of the needle droplet 15a shown by the solid line in FIG. It will now move to the right position shown.

Further, a hook whose outer hook swings in conjunction with the driving of the sewing machine is arranged in the sewing machine bed portion a, and the hook 52 of this hook cooperates with the needle 14 to move the needle 14. A lock stitch is formed by knotting the upper thread held in the bobbin case 53 of the hook and the lower thread stored in the bobbin case 53 of the hook.

Furthermore, although not shown, a well-known thread cutting mechanism is arranged in the sewing machine bed part a, and this thread cutting mechanism
It operates when the needle 14 rises from the bottom dead center to the top dead center after the final needle drop of the cycle stitch, and catches and cuts one thread leg of the needle thread loop caught by the tip 52 and the bobbin thread. It is supposed to be done.

The present invention has the above configuration, and its operation will be explained next.

This cycle sewing machine 1 is designed to stop after forming 16 stitches after being driven, and one cam groove 7a of the feed cam 7 is arranged so as to start from the first stitch of the cycle stitch, as shown in FIG. Up to the 7th stitch, the needles are dropped alternately at three positions separated from the left and right on the workpiece, then the 8th stitch is dropped at the same location as the 7th stitch, and the needles are dropped alternately again from the 8th stitch to the 14th stitch. After the 15th stitch is dropped in the same location as the 14th stitch, the 16th stitch is dropped in the vicinity of the 14th and 15th stitches, so that the base plate 18 of the holding mechanism 16 is moved left and right. The other cam groove 7b moves the board 18 forward after the 7th needle drops and before the 8th needle drops, and moves the board 18 forward after the 16th needle drops until the sewing machine stops. It is formed to move back backwards.

First, when the sewing machine is stopped, the lifting mechanism (not shown) is in operation, and the upper end of the passive piece 24 is moved rearward, so that the upper and lower plates 20 resist the elastic force of the spring 23. The holding arm 19 is rotated clockwise about the horizontal shaft 17, and the pair of holding arms 19 at the tip thereof are raised from the upper surface of the receiving plate 17 (as indicated by the two-dot chain line in FIG. 4).

Therefore, when sewing the four-hole button B shown in FIG.
, operate the adjustment lever 35 to move and adjust the interlocking pin 38 to an appropriate position away from the axis of the support shaft 10, which is the center of rotation of the second rotating arm 11, and screw in the nut 40 to adjust the interlocking pin 38. The pin 38 is fastened to the transmission body 31, the four-hole button B is held between each holding arm 19, and the fabric to be sewn is inserted between the lower surface of the holding arm 19 and the upper surface of the receiving plate 17. to start the sewing machine.

By this sewing machine starting operation, the lifting mechanism becomes inactive, and the upper and lower plates 20 are lowered by the elastic force of the spring 23, and the holding arm 19 is lowered onto the material to be sewn, and the upper surface of the receiving plate 17 is connected to the material to be sewn. The sewing machine 1 is driven at the same time as the cloth is clamped.

7 drive of the sewing machine 1 causes the operating shaft 5 to rotate, the feed cam 7 to rotate, and the first rotating arm 9 to rotate while being guided by one of the cam grooves 7a, and with this rotation, the guide pin 25
reciprocates on the sewing machine bed from side to side (Y direction in FIG.
It reciprocates left and right along the upper surface of the throat plate 15 around the axis of the needle plate 15.

Due to this reciprocating movement, the button B held by the holding arm 19 and the cloth to be sewn which is held between the holding arm 19 and the receiving plate 17 reciprocate from side to side on the sewing machine sewing section, that is, reverse feed and forward feed. The needles 14 are alternately inserted into the upper two holes of the four holes of button B in FIG. It is formed.

When the needle drop of the seventh stitch is completed and the needle 14 rises, the second rotating arm 1 is moved by the other cam groove 7b of the feed cam 7.
1 is rotated by a certain amount clockwise in FIG. 1 around the axis of the support shaft 10, and this rotation causes the transmission body 31 to rotate around the support shaft 32 by a certain amount in the clockwise direction in FIG. is rotated clockwise.

This rotation of the transmission body 31 causes the base plate 18 to move rearward (to the left in FIGS. 2 and 4) along the upper surface of the throat plate 15 via the ball-and-socket shaft 29, thereby causing the four buttons B in FIG. The operations are again performed alternately starting from the left hole of the lower two holes.

Then, after the 13th needle drop and before the 14th needle drop, the button B and the sewing material move to the right, that is, are fed backwards, so that the 14th needle drop is as shown in Figure 7. As shown in A of FIG.
Therefore, a hit stitch is formed at the 14th needle drop.

Therefore, the needle entry of the 15th stitch is 14 after the 14th needle entry.
Before the needle is moved to the same position as the stitch, the chevron-shaped cam 51 arranged on the outer periphery of the feed cam 7 engages the engagement pin 4 of the rotating lever 43.
3a, the rotation lever 43 is rotated counterclockwise in FIG. 1 against the elastic force, and as a result of this rotation, the bobbin thread catcher 49 is rotated counterclockwise in FIG. 3. As it rotates, the hook portion 49a at its tip moves to the right from the solid line position, and as a result of this movement, it captures the bobbin thread that is connected to the lower surface of the fabric to be sewn and the bobbin case 53, and removes the bobbin thread as shown in FIG. As shown in C, the needle is forcibly moved to the right side of the path of the needle 14, and after this movement, the 15th stitch is dropped on the left side of the bobbin thread, and a hit stitch is again formed.

As a result of two consecutive pitch stitches being formed by the 14th and 15th needle drops at the same position, a knot is formed in which the upper thread and lower thread are intertwined in multiple pieces, as shown in E in Figure 7. After the needle drop of the 15th stitch, the needle thread is pulled up by a sewing machine balance (not shown), and the knot is firmly tightened.

After this knot is formed, the 16th needle drop is performed near the 14th and 15th needle drop positions, and when the needle 14 rises after the needle drop, the uncut mechanism is activated, and the 16th stitch is When the needle drops, one of the thread membranes of the needle thread loose caught by the tip 52 of the hook and the bobbin thread are cut, and the cam groove 7b of the feed cam 7 cuts the second rotating arm 1.
1 is rotated back in the counterclockwise direction in FIG. 1, contrary to the above, the board 18 is moved back forward (to the right in FIGS. 2 and 4), and the elevating mechanism is activated to move the passive piece 24 The upper end of the sewing machine 1 is moved rearward, the upper and lower plates 20 are rotated clockwise again, the holding arm 19 is raised from the upper surface of the receiving plate 17, and the sewing machine 1 is stopped.

Next, when attaching the two-hole button B shown in FIG.
0, and then operate the adjustment lever 35 to move and adjust the interlocking pin 38 to a position that coincides with the axis of the support shaft 10, which is the center of rotation of the second rotating arm 11. Even if the second rotating arm 11 is rotated by the cam groove 7b of the feed cam 7 between after the needle drops on the 8th stitch and before the 8th needle drops, and after the 10th needle drops until the sewing machine stops, The rotation is no longer transmitted to the transmission body 31, so that the needle drops between the two holes of button B according to the needle drop sequence shown in FIG.

As can be seen from the above configuration, by changing the position of the interlocking pin 38 with respect to the center of rotation of the second rotation arm 11, the amount of rotation of the transmission body 31 for a certain amount of rotation of the second rotation arm 11 can be changed. In other words, the amount of movement of the board 18 in the front and rear direction can be changed, and therefore, when sewing a four-hole button, the two holes on the upper side and the two holes on the lower side can be sewn by changing the type of button. If the distance between the two is changed, the position of the interlocking pin 38 can be changed according to the distance, and the position of the interlocking pin 38 can be easily changed by rotating the adjustment lever 35. At the same time, for positioning, the locking piece 35b of the adjustment lever 35 is fitted and locked into the locking hole corresponding to the planned position of the interlocking pin 38 among the plurality of positioning locking holes 41a provided in the indicator plate 41. You can do it accurately by doing this.

As described above, the present invention provides a lock in which the upper thread and lower thread are tied together to form a knot by dropping the needle twice in succession at the same location on the workpiece at the final stage of cycle sewing. In a sewing cycle sewing machine, to forcibly control the bobbin thread connected to the bottom surface of the workpiece and the hook to a position where a pitch stitch is formed before at least the second needle drop of the above two needle drops. For example, in a sewing machine in which a hit stitch is formed by the first needle drop by reversing the sewing material before the first needle drop, it is possible to By controlling the bobbin thread to the position where a hit stitch is formed by the above-mentioned control mechanism before the needle drops, it is possible to reliably form a pitch stitch twice in succession with these two needle drops. In a sewing machine in which a part-ft stitch is formed by the first needle drop by forwarding the sewing material before the first needle drop, the control mechanism is activated before the first needle drop. The lower thread is forcibly controlled from the position where a part-eft stitch is formed to the position where a hit stitch is formed, and the control mechanism also moves the bobbin thread to a position where a pitch stitch is formed before the second needle drop. If controlled, it is possible to reliably form pitch stitches twice in a row in the same way, and therefore it is possible to always reliably form a knot between the upper thread and bobbin thread at the final part of cycle sewing. Effects can be obtained.

In the above embodiment, in a sewing machine in which a hit stitch is formed by the first needle drop by reversing the sewing material before the first needle drop, In this example, the lower thread is forcibly controlled to a position where a hit stitch is formed using a control mechanism, but as mentioned above, the material to be sewn may be fed forward before the first needle drop. Therefore, in a sewing machine that is designed to form a part-eft stitch by the first needle drop, a control mechanism forces the lower thread to form a hit stitch before each of the first and second needle drops. If the position is controlled, pitch stitches can be reliably formed twice in succession with these two needle drops, so that the same effect as in the above embodiment can be obtained.

In addition, in the above embodiment, a cycle sewing machine was used to sew buttons to the fabric to be sewn by cycle sewing, but it is also possible to use a cycle sewing machine to sew buttons to the fabric to be sewn using cycle stitching, or to sew button holes on a fabric to be sewn. Even when the present invention is applied to a cycle sewing machine for performing overlock stitches, the same effects as in the above embodiment can be obtained.

Furthermore, in the embodiment described above, the rotary lever 43 is rotated by the chevron-shaped cam 51 disposed on the outer periphery of the feed cam 7 that rotates in conjunction with the drive section of the sewing machine.
, and controls the movement of the bobbin thread from the needle path to the side where the hit stitch is formed. A microswitch is disposed on the path of the cam 51, and an electromagnetic pressure is connected to the connecting link 46, and the electromagnet is driven by an electric signal generated by the operation of the microswitch to operate the bobbin thread catcher 49. Alternatively, instead of the chevron-shaped cam 51, a permanent magnet may be arranged around the outer circumference of the feed cam 7, and instead of the microswitch, the permanent magnet may be placed at a position facing the needle before the needle drops for knot formation. A Hall IC may be disposed, and the electromagnet may be driven by an electric signal generated by the opposing permanent magnets and the Hall IC to operate the bobbin thread catcher 49. Furthermore, a permanent magnet may be disposed on the main shaft of the sewing machine. At the same time, a Hall IC is placed oppositely on the path of the permanent magnet, and the number of stitches before the needle drops for knot formation is counted, that is, the number of electrical signals generated by the permanent magnet and the Hall IC is counted. By doing so, the electromagnet may be driven to operate the bobbin thread catcher 49.

[Brief explanation of drawings]

Figure 1 is a perspective view of the entire sewing machine seen from the right side, Figure 2 is a perspective view of the entire sewing machine seen from the left side, and Figure 3 is the sewing machine bed showing only the control mechanism for controlling the bobbin thread. 4 is a partially sectional left side view of the longitudinal feeding mechanism of the holding mechanism, FIG. 5 is a partially sectional front view of the longitudinal feeding mechanism of the holding mechanism, and FIG. 6 is a partially sectional plan view of the longitudinal feeding mechanism of the holding mechanism. FIG. 7 is an exploded perspective view of the front-rear feed mechanism, FIG. 7 is an explanatory view of the operation showing the order of knot formation, and FIG. 8 is an explanatory view of needle drops in sewing four-hole and two-hole buttons. The holding mechanism is 16, and the feeding mechanism? , 9, 11. 31, control mechanism is 43, 46, 48, 50, 49° 51
It is.

Claims (1)

[Claims] 1 It is driven by the starting operation of the sewing machine, and the needle and hook work together below the needle droplet on the throat plate to form a lock stitch in which the upper thread held by the needle and the lower thread stored in the hook knot together. In a cycle sewing machine that stops after forming a certain number of stitches, a holding mechanism is provided, in which a holding part for holding a workpiece on the sewing part of the sewing machine is movable along the sewing machine bed surface, and a driving mechanism for the sewing machine. interposed between the part and the holding mechanism, the holding mechanism is interlocked with the driving part of the sewing machine, and is movable in a predetermined direction so as to form a predetermined cycle stitch consisting of a fixed number of stitches on the workpiece; A feeding mechanism capable of interrupting the movement of the holding mechanism so that the needle drops twice in succession at the same location on the sewing material at the final stage of stitch formation, and each of the two needles at the final stage of seam formation. It can be operated mechanically or electrically before the needle drops or at least before the second needle drops, and by its operation, the lower thread connected to the bottom surface of the workpiece and the hook is moved from the needle path to the side where the hit stitch is formed. A knot forming mechanism for a cycle sewing machine equipped with a control mechanism that enables movement control.