JPH10108990A - Thread-cutting device for multiple-needle sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use effectively in a sewing machine having no partial projections, especially in one having a cylindrical bed, and to make a remarkable accur in cutting a specific thread, by reciprocating a movable knife smoothly and steadily. SOLUTION: An iron plate 5A in which many needle-location-holes 12 are parallelly made is integrated with a base 5 used for mounting it to a bed 1. A fixed knife 6 arranged on the underside of the base 5 is fixed to the base 5 at both its ends. Also, a movable-knife base 8 fixedly holding many movable knives 7 arranged below the fixed knife 6 is driven and moved via a pair of air cylinders 11, arranged fixedly below the base 5 and on both sides of the needle-location-holes 12 in the direction where they are arranged parallelly, so as to reciprocate straight in a sewing direction between the position of a thread-hooking action and the position of a thread-cutting position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread cutter for a multi-needle sewing machine such as a chain stitch sewing machine having a cylindrical bed used for sewing an annular portion (circle) such as a cuff or a hem of clothing. It relates to the device, and in particular, performs ring stitching on the fabric with a lower thread supplied by a looper vertically oscillated below the needle plate and an upper thread supplied by a number of needles,
The present invention relates to a thread trimmer for a multi-needle sewing machine which cuts an upper thread and a lower thread after the chain stitching by a fixed knife and a movable knife below a needle plate.

[0002]

2. Description of the Related Art As a thread cutting device for a multi-needle sewing machine of this type, a device disclosed in Japanese Patent Application Laid-Open No. 4-272788 has been proposed. The thread trimming device disclosed in the publication has a U-shape fixed to the sewing machine bed in a plan view.
A needle plate separately manufactured from the base is attached to the base for mounting the needle plate in the shape of a letter, and a fixed knife is fixed to the open end side of the base, and is arranged below the fixed knife. On the movable knife bracket held slidably in the sewing direction with respect to the base, a large number of movable scalpels are fixedly held corresponding to a large number of needle drop holes formed in parallel with the needle plate,
A single cylinder is attached to the base so as to protrude outward from the periphery thereof and can be extended and contracted in the sewing direction, for example, a single-acting compressed air cylinder. ), The movable knife bracket is fixedly connected to the leading end, so that the single threaded cylinder expands and contracts to fix the thread hooking action position of the thread hooking portion of the plurality of movable knives and the hooked thread. It is configured to linearly reciprocate between a thread cutting action position where it is transferred to the knife side and cut by both knifes.

[0003]

However, in the conventional thread trimmer of a multi-needle sewing machine having the above configuration,
Since many movable scalpels and movable scalpel brackets are reciprocated by a single cylinder, even if the tip of the movable side member of the cylinder is fixedly connected to any position in the width direction of the movable scalpel bracket, During the movement, mechanical retraction or bumping occurs, and the reciprocating movement of the movable knife tends to be slippery and unstable, and as a result, there has been a problem that a predetermined thread cutting operation cannot be performed accurately. In addition, since the base for mounting the needle plate and the needle plate are separate bodies, and the fixed knife and the movable knife bracket are fixed or slidably held on the base side, the assembly errors of these components are accumulated. As a result, the positional accuracy of the movable knife and the amount of reciprocating movement (stroke) are deviated, and this is also a factor that deteriorates the thread trimming accuracy. Further, since the above cylinder is mounted so as to protrude greatly from the periphery of the base, when applied to a sewing machine having a cylindrical bed, the cylinder cannot be installed in the cylindrical bed, and the cylinder is located outside the bed. It becomes a form locally protruding, which is not preferable for this type of sewing machine used for sewing a circular portion (round).

[0004] The present invention has been made in view of the above circumstances, has no local protrusion, and can be effectively applied to a sewing machine having a cylindrical bed in particular. It is a primary object of the present invention to provide a multi-needle sewing machine thread trimming device that can reciprocate stably and can significantly improve a predetermined thread trimming accuracy.

Another object of the present invention is to simplify the structure of the driving cylinder of the movable knife so that the entire apparatus can be made compact.

[0006]

According to a first aspect of the present invention, there is provided a thread trimmer for a multi-needle sewing machine according to the present invention, wherein a number of needle drop holes are formed in parallel. A mounting base for attaching to the sewing machine bed having the unit integrated, and a fixed scalpel having both ends fixed to the mounting base so as to be arranged on the lower surface side of the needle plate portion and cut the upper thread and the lower thread, A movable knife base, which is disposed below the fixed knife and has a large number of movable knifes having hooking portions for upper thread and lower thread at positions corresponding to the needle drop holes, fixedly held, and a movable knife base below the movable knife base. Along with elastically pressing the plurality of movable knives against the lower surface of the fixed knives arranged,
A number of springs for holding the cut end of each lower thread between the movable knife and the spring are mounted, and a spring base fixed to the mounting base, and both sides of the needle drop hole in the needle plate in the parallel direction. A plurality of movable scalpels are arranged and fixed below the mounting base, and the plurality of movable knives are thread-hung action positions by the hook portions, and the thread-cutting action positions for transferring the hooked yarn to the fixed knife side for cutting. And a pair of cylinders for linearly reciprocatingly moving the movable knife base in the sewing direction so as to reciprocate over the range.

According to the first aspect of the present invention, a plurality of movable scalpels and a movable scalpel base for fixing and holding the movable scalpels are arranged on both sides of the plurality of needle drop holes in the parallel direction. The reciprocating driving movement is performed through the above, so that the reciprocating movement can be performed smoothly and stably without any twisting or bumping. In addition, since the needle plate portion having a large number of needle drop holes formed in parallel is integrated with the base for attachment to the sewing machine bed, the fixed knife and the movable knife base fixed to the base side and the needle plate portion The mounting error between the movable knife and the reciprocating movement amount (stroke) accuracy can be increased, and the high assembling accuracy and the smooth and stable reciprocating motion performance as described above can be achieved. As a result, the predetermined thread trimming accuracy can be significantly improved as compared with the related art. Furthermore, since the pair of cylinders are arranged and fixed below the mounting base so that they do not protrude outward from the periphery of the base, the plane space occupied by the entire thread cutting device including the cylinder is reduced. Make it smaller
When the present invention is applied to a sewing machine having a cylindrical bed, it is possible to adopt a mode in which the entire apparatus is installed in the bed without increasing the size of the cylindrical bed.

[0008] In the thread cutting device for a multi-needle sewing machine according to the first aspect of the present invention, as described in the second aspect, the needle plate portion serves as a working fluid inflow / outflow passage portion for the pair of cylinders. When adopting a configuration formed by drilling the thick portion of the mounting base that is integrated, compared to a case where a piping joint for working fluid in / out for a pair of cylinders is directly attached to the cylinders, Piping hoses and the like do not enter under the base, so that the piping configuration can be simplified and simplified, the thread trimming device can be easily compacted, and operation troubles such as twisting or breakage of the hose can be avoided as much as possible.

Further, in the thread cutting device for a multi-needle sewing machine having the above structure, a large number of movable knives are fixed and held to the movable knives base by screwing from the upper surface thereof. By making the configuration, it is very easy to adjust the tip of each movable knife to the needle,
According to a fourth aspect of the present invention, a stopper that abuts against the movable member of the pair of cylinders and stops the movable knife and the movable knife base from moving toward the thread hooking operation position is located at the abutment position with the sewing machine bed. The movable stop position of the movable knife and the movable knife base toward the line hooking operation position side by adjusting the contact position of the stopper, that is, the needle of the movable knife The position of the fixed knife can be easily adjusted, and furthermore, as described in claim 5, the fixed positions of both ends of the fixed knife with respect to the mounting base can be adjusted in the sewing direction. It is possible to easily adjust the engagement allowance between the movable knife and the movable knife. By hooking action of the yarn by the movable knife, thereby reliably performing the transfer operation and hooking cutting action of the transfer yarn to the fixed female attained the further improvement in a predetermined thread cutting accuracy.

The thread cutting device according to the present invention can be applied to a flat bed sewing machine. In particular, when the thread cutting device is applied to a chain stitch sewing machine having a cylindrical bed, a small diameter sewing machine can be used. It is possible to incorporate the entire thread cutting device into the bed without increasing the size of the cylindrical bed itself, which is desirably as small as possible so that it can also be used for sewing the annular portion, and its effectiveness is high.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a main part showing a thread stitching device of a chain stitch multi-needle sewing machine having a cylindrical bed, which is an application example of the present invention as a multi-needle sewing machine. FIGS. 4 and 5 are front views of FIGS. 2 and 3. In FIG. 1, reference numeral 1 denotes a cylindrical bed in a chain stitch multi-needle sewing machine, through which a sewing machine main shaft (not shown) passes. Partition wall 3 having a through hole 2 for
A space 4 for assembling a thread cutting device to be described later is formed between the three.

The thread cutting device is roughly divided into a mounting base 5 fixed on a peripheral wall surface of the mounting space 4 of the cylindrical bed 1 and a band-shaped fixed knife 6, and a large number of concrete devices. Has a movable knife base 8 in which twelve movable knives 7 are fixedly held in parallel, and a strip-like plate in which twelve back springs 9 respectively corresponding to the movable knives 7 are fixed and held in parallel. It has a spring base 10 and a pair of air cylinders 11 for linearly reciprocatingly moving the movable knife base 8 in the sewing direction.

The mounting base 5 has a needle plate portion in which twelve needle drop holes 12 and long grooves 13 for operating the feed dog are formed in parallel at regular intervals and formed to be thinner than both side portions 5B. 5A are integrated, and the recesses 5b, which engage and hold both ends of the fixed scalpel 6 in the opposite side portions 5B, 5B located on the near side in the sewing direction with respect to the needle plate portion 5A, 5b are formed. The fixed knife 6 has long holes 6a, 6a at both ends thereof. The fixed knife 6 is dropped into the concave portions 5b, 5b so that the blade edge 6b is located below the lower surface of the needle plate portion 5A. The bolt 1 inserted into the slots 6a, 6a
4B, 14B on both sides of the mounting base 5
5B is fixed so that the position can be adjusted in the sewing direction.

The movable knife base 8 has a U-shape in plan view, and the base ends of the twelve movable knifes 7 as shown in FIGS. 6 and 7 on the upper surface of the intermediate connecting plate portion 8a. The parts are screwed and fixed via bolts 15 which can be screwed from above at two places in the front and rear direction in the sewing direction, and long grooves 8c, 8c along the sewing direction are formed in both side plate parts 8b, 8b. And these long grooves 8c on both sides,
8c and guide rollers 16, 16 fitted in the long grooves 8c, 8c, and linearly within a certain range in the sewing direction along the lower surfaces of the fixed knife 6 and the both sides 5B, 5B of the base 5 in the sewing direction. The base 5 is slidably supported by the base 5.

The strip-shaped spring base 10 is disposed below the movable knife base 8 and both ends thereof are bolts 1.
Spring plates 9a, 9b fixed to the lower surfaces of the front ends of both sides 5B, 5B of the base 5 in the sewing direction via the base plates 7, 17 and stacked vertically as shown in FIG.
The base ends of the twelve back springs 9 are fixed in parallel at two positions in the front and rear direction in the sewing direction from below by bolts 18. These back springs 9 are movable by their distal ends. The scalpels 7 are elastically pressed against the lower surface of the fixed knife 6, and the cut ends of the lower threads of the upper and lower threads cut by the movable knives 7 and the fixed knives 6 are moved to the respective movable knives 7 ... It is configured to be sandwiched and held between the front end of the camera.

The tip of each of the movable knives 7 is supplied by a lower thread and 12 needles (not shown) supplied by a vertical swing looper (not shown) provided below the base 5. Hook portions 7a and 7b having a function of hooking the upper thread and transferring the thread to the fixed knife 6 are formed.

The pair of air cylinders 11, 11 are arranged below both side portions 5B, 5B of the base 5 on both sides in the direction parallel to the needle drop holes 12 in the needle plate portion 5A via bolts 19, 19. Side plates 8b of the movable knife base 8 via guide plates 20, 20 and screw members 21, 21 to the distal ends of piston rods 11A, 11A which are movable members of the pair of air cylinders 11, 11. , 8b are fixedly connected to each other, so that the movable knife base 8 is linearly reciprocated in the sewing direction along with the expansion and contraction of the pair of air cylinders 11, 11 to move the twelve movable knifes 7,. As shown in FIGS. 3 and 5, the hooking portions 7a and 7b at the distal ends thereof are threaded into the needle drop holes 12... And shown in FIGS. Sea urchin, the tip of the engaging portion 7a, 7b
Are reciprocated over a thread cutting action position engaged with the blade edge 6b of the fixed knife 6.

The pair of air cylinders 11, 1
The thick portions of both sides 5B, 5B of the base 5 to which the base 1 is fixed are formed by piercing in a state where the base 5 is opened at the end face in the sewing direction and the end face in the direction perpendicular to the sewing direction. A flow passage 2 for taking in and out the working air into and out of the cylinder bodies 11B, 11B of the air cylinders 11, 11
A speed controller 23 for controlling the expansion / contraction operation speed of the air cylinders 11, 11 is provided at the open ends of the flow passages 22, 22, respectively.
23 is screw-connected.

Further, the side walls of the space 4 for assembling the thread cutting device in the cylindrical bed 1 are in contact with the distal ends of the piston rods 11A, 11A of the pair of cylinders 11, 11, and the movable knife 7,. Cushion stoppers 24, 2 for stopping the movable knife base 8 from moving toward the thread hooking action position and defining the end of their reciprocating stroke.
4 is the piston rod 1 via the screw members 25, 25.
It is screwed and held so that the contact position with the tip of 1A, 11A can be adjusted freely.

In the thread trimmer of the chain stitch multi-needle sewing machine having the cylindrical bed having the above-described configuration, the movable knife base 8 is linearly moved in the sewing direction as the pair of air cylinders 11 expand and contract. The movable knife 7 is moved back and forth to form 12 movable knives 7.
As shown in FIGS. 3 and 5, when a and 7b are inserted into the needle drop holes 12..., the upper thread and the lower thread are hooked on the hook portions 7a and 7b, and the hooks are hooked. The yarn is transferred to the fixed knife 6 and the movable knife 7
When the hook portions 7a and 7b at the tips engage the blade edge 6b of the fixed knife 6 as shown in FIGS. 2 and 4, the upper thread and the lower thread are cut, and the cut ends of the lower thread are removed. The movable portions 7 are sandwiched and held between the distal end portions of the movable knives 7 and the corresponding back springs 9, and by repeating such operations, sewing of the annular portion (round) is continuously performed.

By the way, in the thread cutting device of the chain stitch multi-needle sewing machine used for sewing the annular portion as described above,
The movable knife base 8 and the movable knife 7 are connected to the needle drop holes 12.
Pair of air cylinders 1 arranged on both sides in the parallel direction
By causing the reciprocating drive movement through the first and the first 11, the movable knife base 8 and the movable knife 7 can be smoothly and stably reciprocated without generating twisting or bumping during the reciprocating movement. Further, by integrating the needle plate portion 5A having the needle drop holes 12 formed in parallel with the mounting base 5 for mounting to the cylindrical bed 1, the fixed knife 6 and the movable knife base 8 fixed to the base 5 side. No assembly error occurs between the movable knife 7 and the needle plate portion 5A, and the accuracy of the mounting position of the movable knives 7 and the accuracy of the reciprocating motion (stroke) can be increased. Smooth and stable reciprocating motion performance
The predetermined thread cutting accuracy can be significantly increased. Further, the pair of cylinders 11 and 11 are attached to the mounting base 5.
The cylinder 1 is fixed to the lower side of the cylinder 1 so as not to protrude outward from the periphery of the base 5.
Even when the plane space occupied by the entire thread trimming device including the thread cutting devices 1 and 11 is reduced and the tubular bed 1 is not enlarged, it is possible to adopt a form in which the entire device is installed in the bed 1.

The pair of air cylinders 11, 1
Since the working air inlet / outlet flow passages 22 for the first cylinder 1 are formed by perforating the thick portion of the mounting base 5, piping joints and the like for working air in / out are provided on the air cylinders 11, 11. Compared to direct mounting, piping hoses do not enter under the base, simplifying and simplifying the piping configuration, making it easier to make the thread cutting device more compact,
Occurrence of operation troubles such as twisting or breakage of the hose can be avoided as much as possible.

Further, in the thread trimmer of the chain stitch multi-needle sewing machine having the above structure, the movable knife 7 is screwed and fixed to the movable knife base 8 via bolts 15 screwed from above. And each movable knife 7... It becomes very easy to adjust the hooks 7 a and 7 b at the tips with respect to the needle,
Further, a stopper 2 made of a cushion material is provided on the cylindrical bed 1.
The piston rods 11A, 11A in the air cylinders 11, 11 are screwed through the screw members 25, 25.
The contact position between the movable knife 7 and the movable knife base 8 is adjusted by adjusting the contact position of the cushion-made stoppers 24, 24 so that the contact position between the movable knife 7 and the movable knife base 8 is adjusted. Side, that is, the position where the movable knife 7 projects into the needle can be easily adjusted, and the fixed positions of both ends of the fixed knife 6 with respect to the mounting base 5 can be adjusted in the sewing direction. The movable knives 7 can easily adjust the engagement margin between the blade edge 6b of the fixed knife 6 and the movable knives 7... The hooking action, the transfer action to the fixed knife 6 side, and the cutting action of the hooked and transferred yarn are all ensured, and the predetermined thread cutting accuracy can be further improved.

In the above embodiment, the cylindrical bed 1
The present invention has been described with reference to the case where the present invention is applied to a thread stitching device of a chain stitch multi-needle sewing machine having the above. Further, the holding means for holding the cut lower thread is not limited to the above embodiment.

[0025]

As described above, according to the first aspect of the present invention, a large number of movable scalpels and a movable scalpel base for fixing and holding the movable scalpels are provided on a pair of needle placement holes arranged on both sides in the parallel direction. Since the reciprocating drive movement is performed via the cylinder, the movable knife and the movable knife base can be smoothly and stably reciprocated without any twisting or bumping during their reciprocating movement. In addition, since the needle plate portion having a large number of needle drop holes formed in parallel is integrated into the mounting base for the sewing machine bed, the fixed knife and the movable knife base fixed to the base side and the needle plate portion The assembling error between the moving knife and the accuracy of the reciprocating motion (stroke) can be enhanced by minimizing the mounting error between the movable knife and the reciprocating motion. , The predetermined thread trimming accuracy can be remarkably improved as compared with the related art. Further, since the pair of cylinders is arranged and fixed below the mounting base and the cylinders do not protrude outward from the periphery of the base, the plane space occupied by the entire thread cutting device including the cylinders is reduced. In particular, when the present invention is applied to a sewing machine having a cylindrical bed, an effect that the entire apparatus can be provided in the bed without increasing the size of the cylindrical bed can be obtained.

According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, in the case where a piping joint or the like for working fluid in / out of a pair of cylinders is directly attached to the cylinder. In comparison, the piping hose and the like do not enter under the base, the piping configuration is simplified and simplified, and the thread cutting device is easy to be compact, and the occurrence of operation troubles such as twisting or breakage of the hose can be avoided as much as possible.

Further, according to the third aspect of the present invention,
It is very easy to adjust the tip of each movable knife tip,
According to the fourth aspect of the present invention, the abutment position of the stopper that abuts on the movable member of the pair of cylinders and stops the movement of the movable knife and the movable knife base toward the line hooking operation position is adjusted. This makes it possible to easily adjust the movement stop position of the movable knife and the movable knife base toward the line hooking operation position, that is, the position where the movable knife sticks into the needle. Further, according to the invention of claim 5, For example, the engagement allowance between the fixed knife and the movable knife can be easily adjusted, and by adopting a combination of one or more of the configurations as described in claims 3 to 5, each movable knife can be adjusted. To ensure that the thread hooking action, transfer action to the fixed knife side and cutting action of the hooked and transferred thread are performed, thereby further improving the predetermined thread trimming accuracy. It can be.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a main part showing a thread stitching device of a chain stitch multi-needle sewing machine having a cylindrical bed, which is an application example of the present invention as a multi-needle sewing machine.

FIG. 2 is an enlarged plan view showing the thread cutting device in a thread cutting operation state.

FIG. 3 is an enlarged plan view showing the thread trimming device in a thread hooking state.

FIG. 4 is a front view of FIG. 2;

FIG. 5 is a front view of FIG. 3;

FIG. 6 is an enlarged plan view of a main part of the thread cutting device.

FIG. 7 is a front view of FIG. 6;

[Explanation of symbols]

 Reference Signs List 1 cylindrical bed (sewing machine bed) 5 mounting base 5A needle plate 6 fixed knife 7 movable knife 7a, 7b thread catching section 8 movable knife base 9 back spring 10 spring base 11 air cylinder 12 needle drop hole 22 flow passage section 24 cushion material Stopper

Claims (6)

[Claims] 1. A base for attachment to a sewing machine bed in which a needle plate portion having a large number of needle drop holes formed in parallel is integrated, and an upper thread and a lower thread arranged on a lower surface side of the needle plate portion. A plurality of fixed scalpels having both ends fixed to the mounting base so as to be cut, and a large number of upper and lower thread hooking portions disposed below the fixed scalpel and corresponding to the needle drop holes. A movable knife base on which a movable knife is fixedly held, and a plurality of movable knifes arranged below the movable knife base are elastically pressed against the lower surface of the fixed knife, and an end of each cut lower thread is removed. A number of springs sandwiched and held between the movable knife are mounted, and a spring base fixed to the mounting base and arranged below the mounting base on both sides of the needle plate portion in the parallel direction of the needle drop holes. The fixed number of movable The movable knife base is linearly moved in the sewing direction so that the movable knife base reciprocates between the thread hooking action position of the hooking portion and the thread cutting action position where the hooked thread is transferred to the fixed knife side and cut. A thread cutting device for a multi-needle sewing machine, comprising: a pair of cylinders for reciprocating drive movement. 2. The thread of the multi-needle sewing machine according to claim 1, wherein a flow path portion for working fluid in and out of the pair of cylinders is formed by perforating a thick portion of the mounting base. Cutting device. 3. The multi-needle sewing machine according to claim 1, wherein the plurality of movable scalpels are fixed and held to the movable scalpel base by screws from above. 4. A stopper for stopping the movement of the movable knife and the movable knife base to the thread hooking operation position side by contacting the movable side member of the pair of cylinders is provided on the sewing machine bed so as to be adjustable. The thread cutting device for a multi-needle sewing machine according to any one of claims 1 to 3, wherein: 5. The thread cutting device for a multi-needle sewing machine according to claim 1, wherein fixing positions of both ends of the fixed knife with respect to the mounting base are adjustable in a sewing direction. 6. The multi-needle sewing machine according to claim 1, wherein the target sewing machine is a chain stitch sewing machine having a cylindrical bed.