JPH0231793A - Thread cutting device for sawing machine - Google Patents

Abstract

PURPOSE:To cut sewing thread with a slight force surely by letting the tip of a movable blade and the tip of a fixed blade pass each other in a state of flexibly contacting with each other after the movable blade reciprocates and catches a line of sewing thread. CONSTITUTION:The side face 18a of a guide member 18 is flexibly contacted with the tip 5a of a fixed blade 5 by an assisting force in a state in which a restriction by means of a restriction device 25 for preventing a movable blade 6 moving in the axial direction is released. When the extent of the movement of the movable blade 6 in the direction of the assisting force is restricted by the restriction device 25 in this state, the side face 18a of the guide member 18 that is contacted with the tip 5a of the fixed blade 5 is constantly kept at the same position, and the contacting pressure between the movable blade 6 and the fixed blade 5 is kept constant. When the movable blade is rotated, the side face of the guide member is contacted with the tip of the fixed blade at first, and then the movable blade is moved in the axial direction with rotating of the movable blade as the side of the guide member is pushed by the tip of the fixed blade. As a result, as such as state that the side of the guide member is flexibly contacted with the tip of the fixed blade is established, the tip of the movable blade and the tip of the fixed blade pass each other in the state that the tip 6a of the movable blade is flexibly contact with the tip of the fixed blade, so that sewing thread is surely cut.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a thread cutting device for a sewing machine.

[Conventional technology]

A conventional thread cutting device of this type is disclosed in Japanese Patent Application Laid-Open No. 56-10669.
As shown in Publication No. 2, loosen the stud bolt that fixes the drive arm to the rotating wheel of the movable blade, and loosen the locking nut that fixes the movement adjustment screw to the adjustment base. By rotating the movement adjustment screw, the cam plate provided on the movement adjustment screw comes into contact with the end face of the rotation shaft, and as a result, the rotation wheel is moved in the axial direction, and the gap between the movable blade and the fixed blade is moved. The contact pressure is adjusted.

[Problem to be solved by the invention]

In this conventional sewing machine thread cutting device, 1. The movable blade is brought into contact with the fixed force by rotating the movement adjustment screw with a screwdriver, etc., so the contact pressure between the movable blade and the fixed blade changes depending on the degree of tightening of the movement adjustment screw, making it easier to perform the same task. Even if you are a professional, the contact pressure between the movable blade and the fixed blade is too strong or too weak every time you reassemble the movable blade, which can easily lead to mistakes in cutting the sewing thread. had problems that required a high degree of skill. In addition, in the above-mentioned conventional type, the axial position of the rotating shaft is regulated by the cam plate and the drive arm, so when reassembling the movable blade, the stud bolt and lock nut are used to adjust the movement. There was also the problem that each screw had to be operated individually, which required a lot of time.

The present invention has been made in view of the above points, and its purpose is to enable the movable blade to be reassembled easily and in a short time, and to reduce the distance between the movable blade and the fixed blade. To provide a thread cutting device for a sewing machine that can maintain the same contact pressure.

[Means to solve problems]

In order to achieve the above object, the present invention takes the measures as described in the claims above, and its effects are as follows.

[For use]

In a state in which the restriction of the axial movement of the movable blade by the restriction means is released, the belly surface of the guide member is elastically brought into contact with the cutting edge of the fixed blade by a biasing force. In this state, if the limit of movement of the movable blade in the biasing direction is restricted by the restriction means, the position of the belly surface of the guide member that contacts the cutting edge of the fixed blade will always be at the same position, and the contact pressure between the movable blade and the fixed blade will also be reduced. become the same size.

When the movable blade is rotated, the belly surface of the guide member first comes into contact with the cutting edge of the fixed blade, and then as the movable blade rotates, the belly surface of the guide member is pushed by the cutting edge of the fixed blade, and the movable blade is moved in the axial direction. As a result, the belly surface of the guide member comes into elastic contact with the cutting edge of the fixed blade, and the cutting edge of the movable blade comes into elastic contact with the cutting edge of the fixed blade, passing each other and cutting the sewing thread reliably. can.

〔Example〕

The drawings showing the embodiments of the present application will be described below.

1 and 2, reference numeral 1 denotes a needle plate fixed to a well-known bed (not shown) of a sewing machine, in which a needle hole 1a (hereinafter also referred to as needle drop position la) constituting a needle drop position is formed. There is. Reference numeral 2 designates a well-known hook located below the throat plate 1, as shown in FIG.

3 is a thread cutting device disposed below the throat plate 1. In the thread cutting device 3, 4 is a base frame fixedly placed below the throat plate 1, 5 is a fixed blade whose cutting edge 5a is positioned near a line straight connecting the needle drop position 1a and the hook 2, It is fixed to the upper surface of the base frame 4 so as to be replaceable. Reference numeral 6 denotes a movable blade whose base is pivoted to the base frame 4, and whose cutting edge 6a moves reciprocatingly toward the tip 5a of the fixed blade 5 across a line straight connecting the needle drop position 1a and the hook 2. Next, in the base frame 4, reference numeral 1) is a mounting hole through which a mounting bolt (not shown) for fixing to the bed is inserted. 12 is a vertical support hole, 13 is a support hole 12
This is a housing hole formed on the outer periphery of the upper end.

Next, in the fixed blade 5 shown in FIGS. 1 to 4, 15 is a mark marked on the upper surface near the cutting edge 5a as shown in FIG. It may be composed of things.

Next, in the movable blade 6 shown in FIGS. 1 to 4, reference numeral 16 denotes a mounting hole formed in the base, and a rotation shaft supported in the support hole 12 so as to be movable and rotatable in the axial direction. 17
It is removably fitted to the upper end of the. 18 is the movable blade 6
A guide member protruding toward the fixed blade 5 near the cutting edge 6a, and the ventral surface 18a of the guiding member 18 connects the cutting edge 5a of the fixed blade 5 to the cutting edge 6a of the movable blade 6, as shown in FIG.
In the state in which the fixed blade 5 is in contact with the fixed blade 5,
The slope is such that the distance from the ventral surface 5b is wide.

In the guide member 18, 19 is a V-shaped thread hooking portion at the tip, 20 is a space formed on the leading side of the cutting edge 6a, and 2] is between the space 20 and the thread hooking portion 19. The thread guide groove 22 formed on the ventral surface 18a is a thread wiper section, and the sewing thread m is inserted across the line straight connecting the needle drop position 1a and the hook 2.
It is formed in an arc shape to dispel.

Furthermore, in the thread cutting device 3, 24 is a spring that biases the base of the movable blade 6 in a direction in which the ventral surface 6b of the movable blade 6 abuts against the ventral surface 5b of the fixed blade 5, and is housed in the housing hole 13. The movable blade 6 is compressed and interposed between the movable blade 6 and the base frame 4. Reference numeral 25 denotes a regulating means for setting the limit of movement of the movable blade 6 in the biasing direction (upward), and the belly surface of the guide member 18], 8a can be moved at any position to the cutting edge of the fixed blade 5 as shown in FIG. The movable blade 6 is configured to restrict movement in the biasing direction while being elastically abutted against the movable blade 5a. In addition, the cutting edge 5 of the fixed blade 5
The position of the ventral surface 18a of the guide member 18 that is brought into contact with the guide member 18 can be changed as appropriate depending on the type of sewing thread m to be cut. The ventral surface 18a of the guide member 18 is set at a position near where the guide member 18 comes into contact, and when the thread is a thick twisted thread such as woolly thread.
A substantially intermediate position 40 is set at a position where it comes into contact with the cutting edge 5a. In the regulating means 25, 26 is a regulating shaft constituted by the rotation shaft 17, and 27 is a tightened part formed at the other end (lower end) of the regulating shaft 26, which has a smaller diameter than the other overall part. is formed.

Reference numeral 28 denotes a regulating cylinder fitted to the lower end of the regulating shaft 26, and has a screw hole 28a formed in its outer periphery. Reference numeral 29 denotes an embedded bolt screwed into the tapped hole 28a, and is fastened to the tightened portion 27. Reference numeral 30 serves to receive the end face of the regulating cylinder 28, and is constituted by the lower surface of the base frame 4. Next, 31 is a drive arm for reciprocating the movable blade 6, and is provided integrally with the regulating cylinder 28. The distal end 31a of the drive arm 31 is connected to an operating rod that is reciprocated by a drive source (not shown), as is known in the art.

The operation of the above configuration will be explained step by step.

When the sewing thread m connected between the needle drop position 1a and the shuttle hook 2 is cut after finishing the sewing work, the drive arm 31 is moved from the position shown by the imaginary line in FIG. It is rotated back and forth as shown by the arrow A and the mouth. When the drive arm 31 is moved forward in the direction of arrow A, the rotation shaft 17 is rotated in the same direction, swinging the movable blade 6 from the standby position shown by the imaginary line in FIG. 1 to the operating position shown by the solid line. . Due to the swinging of the movable blade 6, the abdominal surface 18a of the guide member 18 is moved to the fixed blade 5.
is separated from the cutting edge 5a of the regulating cylinder 2 of the regulating means 25.
8 is in contact with the current surface 30 of the base frame 4, the movement of the movable blade 6 in the biasing direction is restricted, and the movable blade 6 is in contact with the ventral surface 1.
Height 1 when 8a comes off the cutting edge 5a of the fixed blade 5
is maintained. As the movable blade 6 swings to the operating position, the thread wiper 22 crosses a line that straightly connects the needle drop position 1a and the hook 2, and sweeps away the sewing thread m located there. and fixed blade 5.

Next, when the drive arm 31 is moved back in the direction of the arrow, the rotation shaft 17 swings the movable blade 6 from the operating position to the standby position.

As the movable blade 6 swings toward the standby position, the thread hooking part 19 first catches the sewing thread m and urges it, and in this state, the tip of the guide member 18 enters below the cutting edge 5a of the fixed blade 5, As a result, the sewing thread m is guided into the thread guide groove 21. Thereafter, the ventral surface 18a of the guide member 18 comes into contact with the cutting edge 5a of the fixed blade 5 as shown in FIG. It digs in and is pushed down slightly. As a result, the ventral surface 18a of the guide member 18 comes into elastic contact with the cutting edge 5a of the fixed blade 5, and in this state, the cutting edge 6a of the movable blade 6 passes the cutting edge 5a of the fixed blade 5 as shown in FIG. Then, the sewing thread m is cut between the double-edged lights 6a and 5a.

In the above case, when the cutting edge 6a passes the cutting edge 5a, they are elastically in contact with each other due to the biasing force of the spring 24, so that the sewing thread m can be reliably cut between the cutting edges 6a and 5a.

Next, when reassembling the movable blade 6 for replacement or repair, first loosen the embedded bolt 29, and in this state, the rotation shaft 17
(Regulation shaft 26) is pulled up and removed from the support hole 12, and the movable blade 6 is replaced or repaired. After that, after fitting the rotating shaft 17 into the support hole 17 again, the tip of the guide member 18 is overlapped with the lower side of the fixed blade 5, and the same position as the previous time on the ventral surface 18a of the guide member 18 is made using the mark 15 as a guide. is brought into elastic contact with the cutting edge 5a of the fixed blade 5. Next, in the above state, the regulating cylinder 28 is fitted to the lower end of the rotating shaft 17 and is brought into contact with the surface 30 for the time being, and the embedded bolt 29 is tightened. As a result, the cutting edge 6a of the movable blade 6 can be easily assembled to the cutting edge 5a of the fixed blade 5 so that they pass each other at the same timing and with the same amount of contact pressure.

Next, if the sewing thread m is changed to another type with a different thickness, etc., loosen the embedded bolt 29 in the same way as when reassembling the movable blade 6 guide member]8 ventral surface 18
The desired position of a is brought into elastic contact with the cutting edge of the fixed blade 5 using the mark 15 as a guide, and then the embedded bolt 29 is tightened again. As a result, the position of the ventral surface 18a of the guide member 18 that comes into contact with the cutting edge 5a of the fixed blade 5 is changed to a desired position, and various sewing threads can be reliably cut.

FIG. 5 shows a different example of the regulating means 256, in which a pivot 17e that also serves as a regulating shaft is planted in the base frame 4e, and a mounting hole 16e of the movable blade 6e is rotatably fitted into the pivot 17e. A regulating cylinder 28e for preventing the movable blade 6e from coming off is fitted to the upper end of the pivot 17e, and a set screw 29e is attached to the regulating cylinder 28e.

It should be noted that parts that are considered to have the same or equivalent structure as those in the previous figure in terms of function are given the same reference numerals as in the previous figure with the letter e, and redundant explanations are omitted.

〔Effect of the invention〕

As described above, in the present invention, when cutting the sewing thread m existing between the throat plate 1 and the hook 2, the movable blade 6 rotates back and forth to hook the sewing thread m, and then the cutting edge of the movable blade 6 6a is fixed blade 5
The thread m passes each other in elastic contact with the cutting edge 5a of
It has the effect of reliably cutting with a light force, and in addition, when the movable blade 6 is assembled or reassembled for replacement or repair, the abdominal surface 18a of the guide member 18 is biased against the cutting edge 5a of the fixed blade 5. It is possible to restrict the movement of the movable blade 6 in the biasing direction with the movable blade 6 in resilient contact with the movable blade 6 in a fixed position, and to adjust the movable blade 6 when assembling or reassembling the movable blade 6. This can be done easily and in a short time, and it also has the effect of making the contact pressure between the cutting edge 5a of the fixed blade 5 and the cutting edge 6a of the fixed blade 6 uniform.

In addition, when the thickness of the sewing thread m to be cut changes, by shifting the contact position of the cutting edge 5a of the fixed blade 5 against the ventral surface 18a of the guide member 18 toward the distal end, it is possible to first contact the cutting edge of the fixed blade 5. The position of the ventral surface 18a of the guide member 18 that comes into contact can be set to any position suitable for the type of sewing thread m, and as a result, when a thick sewing thread is used, the contact position of the cutting edge 5a of the fixed blade 5 can be set to the position where the cutting edge 5a of the fixed blade 5 contacts the cutting edge 6.
This has the effect of making it possible to securely cut the sewing thread by moving it away from the thread a, and when using a thin thread, moving the abutment position closer to the cutting edge 6a to reduce the amount of sliding between the fixed blade 5 and the movable blade 6.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is a perspective view showing a thread cutting device of a sewing machine, FIG. 2 is a side view showing a part of FIG. 1 in cross section, and FIG. FIG. 4 is a sectional view taken along line IV-r'/of FIG. 3, and FIG.
The figure is a perspective view showing a different example, partially in section. 1... Throat plate, 2... Hook, 3... Thread cutting device, 5...
... fixed blade, 5a... cutting edge, 5b... ventral surface, 6...
・Movable blade, 6a...Blade tip, 6b...Blind surface, 18...
-Guide member, 18a... ventral surface, 24... spring, 25.
...Regulatory measures.

Claims (1)

[Claims] The base frame (4), which is fixed below the throat plate (1) on the bed of the sewing machine, has its own cutting edge (5a) attached to the needle plate (1).
The fixed blade (5) is fixedly installed so as to be located near a straight line connecting the needle drop position (1a) of the sewing machine and the hook (2) of the sewing machine, and the movable blade (6) is provided with a pivoting device. (6
The cutting edge (6a) of the fixed blade (5) crosses the line straight connecting the needle drop position (1a) and the hook (2), and the cutting edge (6a) of the fixed blade (5)
In the sewing machine thread cutting device which is capable of freely reciprocating in the direction a), the pivoting portion of the movable blade (6) is attached to the base frame (4).
), and is biased in a direction in which the ventral surface (6b) of the movable blade (6) abuts against the ventral surface (5b) of the fixed blade (5). A guide member (18) protruding toward the fixed blade (5) is provided near the cutting edge (6a) of the movable blade (6), and the ventral surface (18a) of the guide member (18) is connected to the fixed blade ( In a state where the cutting edge (6a) of the movable blade (6) is in contact with the cutting edge (5a) of the fixed blade (5), the ventral surface (5) of the fixed blade (5) is
b), and is further provided with a regulating means (25) for setting the limit of movement of the movable blade (6) in the urging direction with respect to the base frame (4). A thread cutting device on a sewing machine.