JPH0638878U - Sewing machine thread trimmer - Google Patents

Abstract

(57) [Abstract] [Purpose] In a thread cutting device of a sewing machine, a thread holding member 3 for sandwiching an upper thread and a lower thread after cutting in cooperation with a movable blade 26.
The durability and reliability of 0a can be improved. [Structure] During thread cutting, the movable blade 26 is moved forward by the thread cutting solenoid at the thread cutting timing and then moved back. When the movable blade 26 moves forward, the upper thread NS and the lower thread BS are guided so as to be caught, and when the movable blade 26 returns, the upper and lower threads NS, BS are returned to the thread cutting position while being rotated. Immediately after that, the upper and lower threads NS in cooperation with the fixed blade 24,
Disconnect the BS. At this time, the thread holding portion 30a of the thread holding member 30 below the movable blade 26 is cut by the cut upper and lower threads N.
The S and BS are clamped in cooperation with the movable blade 26. Here, since a minute gap is formed between the yarn holding portion 30a and the movable blade 26, both upper and lower yarns NS that are clamped immediately after the cutting even if the yarn waste generated during the yarn cutting is placed on the yarn holding portion 30a. , Removed by BS.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a thread trimming device of a sewing machine, and more particularly to a thread trimming device for improving durability of a thread holding member that holds an upper thread and a lower thread after cutting in cooperation with a movable blade.

[0002]

[Prior art]

 Conventionally, this type of thread cutting device for a sewing machine is provided between a needle plate and a thread catcher, automatically cuts an upper thread and a lower thread at a predetermined thread cutting timing, and cuts the upper and lower threads. It is configured to hold both threads. For example, in Japanese Utility Model Publication No. 46-13219, a fixed blade is fixed to the lower surface of a needle plate, and a movable blade pivotally attached to a machine frame of a bed is rotatably provided immediately below the fixed blade. Immediately below the movable blade, a thread catching member made of a thin plate-shaped spring material is attached to the machine frame so that the thread catching section presses the movable blade after thread cutting, and the thread is cut by the fixed blade and the movable blade. There has been proposed a thread cutting device for a sewing machine configured to elastically sandwich both of the upper and lower yarns that are held by a movable blade in cooperation with a movable blade.

[0003]

[Problems to be solved by the device]

 However, in the thread cutting device of the sewing machine described in Japanese Utility Model Publication No. 46-13219, since the thread catching member is provided below the fixed blade and the movable blade, thread scraps, dust, etc. generated at the time of thread cutting. Are gradually accumulated on the upper side of the yarn catching member, that is, between the movable blade and the yarn catching member, and elastically held. Therefore, when a large amount of yarn scraps or dust is accumulated in the yarn catching portion, the yarn catching member is largely bent downward, and the thickness of the yarn catching member is usually thinner than 0.1 mm. When the upper and lower yarns cut by the above method are sandwiched, there is a problem that the yarn catching member exceeds the limit of elastic deformation and is broken.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to improve the durability of a thread holding member that holds an upper thread and a lower thread after cutting in cooperation with a movable blade. An object of the present invention is to provide a thread trimming device for a sewing machine which can improve reliability.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, a thread cutting device for a sewing machine according to claim 1 is provided in a sewing machine bed portion and cuts an upper thread and a lower thread extending from a work cloth at the end of a sewing operation, The fixed blade fixed to the machine frame of the bed part and the machine blade pivotally attached to the machine frame immediately below the fixed blade so that the needle thread and the bobbin thread captured by reciprocating rotation cooperate with the fixed blade. A movable blade for cutting with a movable blade, a drive means for reciprocating the movable blade at a thread cutting timing, and a thread holding portion for sandwiching the cut upper thread and lower thread in cooperation with the movable blade. The thread holding member is attached to the machine frame below the movable blade with a minute gap between the holding section and the movable blade. The thread holding member may have a plate thickness of at least 0.1 mm.

[0006]

[Action]

 In the thread cutting device for a sewing machine according to the first aspect of the present invention, when the thread is cut, the movable blade is driven forward by the drive means at the thread cutting timing and then driven backward. Then, when the movable blade moves forward, the upper thread and the lower thread are guided so that they can be caught, and when the movable blade returns, the upper and lower threads return to the thread cutting position while catching these upper and lower threads, Immediately after that, the upper and lower threads are cut in cooperation with the fixed blade. At this time, the thread holding portion of the thread holding member provided below the movable blade holds the cut upper and lower threads in cooperation with the movable blade. Here, since there is a minute gap between the thread holding section and the movable blade, even if the thread scraps generated during thread cutting are placed on the thread holding section, the upper and lower threads sandwiched immediately after cutting will Will be removed. Therefore, since the yarn holding section only holds the upper and lower yarns that have been cut at all times, the yarn holding member does not break. When the thread holding member has a plate thickness of at least 0.1 mm or more (claim 2), the amount of flexure due to elastic deformation of the thread holding member can be increased and the thread holding member of the thread holding member can be compared. Even if lint is accumulated, the yarn holding member can be reliably prevented from being broken.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. The present embodiment is a case where the present invention is applied to a thread cutting device of an embroidery sewing machine provided in a multi-head embroidery machine. First, a description will be given of the multi-head embroidery machine M, as shown in FIG. 1, on the rear side of the upper surface of the base frame 1 extending in the left-right direction, a sewing machine supporting a rectangular shape in plan view having a predetermined length in the left-right direction is supported. A board 2 is provided, and three embroidery machines MH are arranged on the sewing machine support board 2 in a row in the left-right direction at predetermined intervals. At the front end of the arm portion 3 of the embroidery sewing machine MH, needle bar cases 7 having 12 needle bars (not shown) arranged in a row in the left-right direction are mounted, and needle bars not shown in the figure are attached. The needle bar case 7 can be moved in the left-right direction by the bar switching mechanism, and the needle bar for forming embroidery stitches with the embroidery thread of a desired color can be selectively selected.

On the other hand, as shown in FIG. 1, the bed body 5 at the lower end of the pedestal 4 connected to the arm 3 is mounted on the sewing machine support plate 2, and the cylinder bed is inserted from the front end of the bed body 5. 6 extends forward, and a front end of the cylinder bed 6 is provided with a thread catcher 18 and a thread trimming device 20, which will be described later, and cooperates with a sewing needle 8 attached to a selected needle bar to obtain a desired thread. When the stitches are formed on the work cloth with the color embroidery threads, when the sewing is completed, the upper and lower threads NS / BS are formed by the thread cutting mechanism that is formed in the same manner as the thread cutting mechanism disclosed in Japanese Patent Application No. 4-281531. (See Fig. 4) can be disconnected automatically. Here, an upper shaft (not shown) for moving the needle bar or the balance 9 up and down and a lower shaft 19 (see FIG. 3) for rotating the thread catcher 18 are connected to a sewing machine motor (not shown). It is driven by a drive shaft 11 which is rotationally driven by the belt 10.

Further, as shown in FIG. 1, a work table 13 is arranged on the front side of the sewing machine support plate 2 so as to be substantially level with the upper surface of the cylinder bed 6, and this work table 13 is provided. A movable frame 16 having a rectangular shape in a plan view extending in the left-right direction is placed on a pair of auxiliary tables 14 and 15 including the work table 13 provided on both left and right sides of the work table 13. The drive frame portion 16a at the right end of the movable frame 16 is driven to move in the X-axis direction (left-right direction) by an X-axis drive mechanism (not shown), and the drive frame portion 16b at the left end thereof and the drive frame portion 16b. The portion 16a and the portion 16a are simultaneously moved and driven in the Y-axis direction (front-back direction) by a Y-axis drive mechanism (not shown). Therefore, the movable frame 16 can be moved on the XY plane by the X-axis drive mechanism and the Y-axis drive mechanism.

Next, the thread cutting device 20 provided at the tip of the cylinder bed 6 will be described with reference to FIGS. 2 to 4. At the upper end of the front end portion of the cylinder bed 6, a plate-shaped base plate 21 is arranged horizontally in the front-rear direction and fixed to the machine frame F with screws or the like. On the upper side of the base plate 21, a mounting plate 22 extending in the front-rear direction is screwed to the left end portion, and a mounting plate 23 is screwed to the right end portion. Here, the upper surface of the right mounting plate 23 is one step higher than the upper surface of the left mounting plate 22.

As shown in FIGS. 2 and 3, a fixed blade 24 having a blade portion 24a at the front end is fixed to the upper side of the mounting plate 23 by a screw 25 in the front leftward direction. As shown in FIGS. 2 and 3, on the upper side of the mounting plate 22, a movable blade 26 having a substantially V-shaped plan view is disposed, and the movable blade 26 is pivotally supported immediately below the fixed blade 24. A pin 27 is pivotally supported on the mounting plate 22. Further, a front end portion of a drive lever 28 extending forward from the bed body portion 5 is rotatably connected to a connecting portion 26a of the movable blade 26 by a pin 29. Therefore, when the drive lever 28 is driven forward, the movable blade 26 is moved from the standby position (thread holding position) shown by the solid line to the swing position shown by the chain double-dashed line, and the drive lever 28 is moved backward. Conversely, when it is driven into and out of, it is returned from the swing position to the standby position. The drive means is composed of the drive lever 28 and a thread cutting solenoid (not shown) for driving the drive lever 28.

The movable blade 26 has a guide portion 26b that guides the upper thread NS and the lower thread BS so that the upper blade NS and the lower thread BS can be engaged with each other during the forward movement, and the upper and lower threads NS and BS are engaged with each other during the backward movement. And a blade portion 26d for cutting the upper and lower yarns NS and BS in cooperation with the blade portion 24a of the fixed blade 24. The blade portion 26d is formed on a part of the circumferential portion of the through hole 26e provided at the tip of the movable blade 26.

Further, on the base plate 21 corresponding to the substantially lower side of the fixed blade 24, a thread holding member 30 for sandwiching the cut upper and lower threads NS and BS in cooperation with the movable blade 26, Below the movable blade 26, it is fixed with screws 31 in a direction substantially similar to that of the fixed blade 24. As shown in FIG. 4, the thread holding member 30 is made of a spring material having a plate thickness T of about 0.5 mm, and is formed by bending the front end portion and the rear end vicinity portion thereof, respectively, and swells upward to move the movable blade 26. A yarn holding portion 30a for holding the upper and lower yarns NS and BS is formed in a portion closest to the position. A small gap G (for example, about 0.5 mm) is provided between the yarn holding portion 30a and the movable blade 26. Here, as shown in FIGS. 2 and 3, the needle plate 32 is placed on the upper side of both the mounting plates 22 and 23 and screwed to form a needle hole 32a. On the other hand, below the thread trimming device 20 in the cylinder bed 6, there is provided a bobbin case BC and a yarn wheel catcher 18 which is rotationally driven by a lower shaft 19.

Next, the operation of thread cutting and thread clamping by the thread cutting device 20 will be described. At the timing of thread cutting at the end of sewing, when the thread cutting solenoid of the thread cutting mechanism disclosed in Japanese Patent Application No. 4-281531 is driven, the drive lever 28 is driven forward through the transmission mechanism. As a result, the movable blade 26 is moved to the swing position. At this time, the upper and lower yarns NS and BS extending from the work cloth (not shown) are guided by the guide portion 26b so that they can be engaged, and the upper and lower yarns NS and BS move to the right of the movable blade 26. Then, when the driving of the thread cutting solenoid is stopped, the movable blade 26 is returned from the swing position to the standby position as the drive lever 28 is driven backward and forward. At this time, the upper and lower yarns NS and BS located on the right side of the movable blade 26 are engaged with the engaging portion 26c, and the upper and lower yarns NS and BS are cooperated by the blade portion 26d and the blade portion 24a of the fixed blade 24.・ BS is cut at the same time, and as shown in FIG. 4, the upper and lower yarns NS and BS moved between the movable blade 26 and the yarn holding portion 30a when the movable blade 26 moves, It is pinched in cooperation with the thread holding portion 30a.

Here, since the minute gap G is provided between the movable blade 26 and the thread holding portion 30a, even if the thread waste generated during thread cutting is placed on the thread holding portion 30a, Immediately after cutting, both upper and lower threads NS and BS that are clamped will be removed. Therefore, the yarn holding section 30a always holds only the cut upper and lower yarns NS and BS, and the yarn holding member 30 can be prevented from being broken, so that the durability and reliability of the yarn holding member 30 are improved. be able to. Moreover, since the thickness T of the thread holding member 30 is as thick as about 0.5 mm, the strength of the thread holding member 30 can be increased, and the durability and reliability of the thread holding member 30 can be further improved. You can

The thread trimming device is not limited to that of this embodiment, and may be configured by combining various members. The thread holding member 30 may be made of synthetic resin or the like other than the spring material, and the plate thickness thereof may be 0.1 mm or more. . Needless to say, the present invention can be applied to thread cutting devices for various sewing machines other than the multi-needle embroidery sewing machine, such as a general sewing machine having only one needle bar.

[0017]

[Effect of device]

 As described above in detail, according to the thread cutting device for a sewing machine according to claim 1, the fixed blade fixed to the machine frame, the movable blade pivotally attached to the machine frame immediately below the fixed blade, A thread holding member fixed to the machine frame is provided below the movable blade, and a minute gap is provided between the thread holding section of the thread holding member and the movable blade. Only the upper and lower yarns, which are always cut while being removed, are sandwiched, and breakage of the yarn holding member can be prevented. Therefore, durability and reliability of the yarn holding member can be improved. When the thread holding member has a plate thickness of at least 0.1 mm (claim 2), the strength of the thread holding member can be increased and the durability and reliability of the thread holding member can be further improved. .

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a multi-head embroidery machine.

FIG. 2 is a schematic plan view of a thread cutting device provided at a front end portion of a cylinder bed.

FIG. 3 is a schematic side view of a thread cutting device and a thread catcher provided on a cylinder bed.

FIG. 4 is a view showing a thread cutting mechanism as viewed from the direction of arrow A in FIG.

[Explanation of symbols]

 M Multi-head embroidery machine MH Embroidery sewing machine 6 Cylinder bed 20 Thread cutting device 24 Fixed blade 26 Movable blade 28 Drive lever 30 Thread holding member 30a Thread holding part

Claims (2)

[Scope of utility model registration request] 1. A thread cutting device for a sewing machine, which is provided in a sewing machine bed section and cuts an upper thread and a lower thread extending from a work cloth at the end of a sewing operation, a fixed blade fixed to a machine frame of the bed section, A movable blade pivotally attached to the machine frame so as to be rotatable immediately below the fixed blade and cutting the upper thread and the lower thread captured by reciprocating rotation in cooperation with the fixed blade; It has a driving means for reciprocating at the timing of thread cutting, and a thread holding section for sandwiching the cut upper thread and lower thread in cooperation with the movable blade, and between the thread holding section and the movable blade. A thread cutting device for a sewing machine, comprising: a thread holding member attached to a machine frame below a movable blade with a minute gap therebetween. 2. The thread holding member is at least 0.1 mm
The thread cutting device for a sewing machine according to claim 1, wherein the thread cutting device has the above plate thickness.