JPH0314149Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a sewing machine that forms a double chain stitch by the cooperation of a needle that reciprocates up and down and a looper that reciprocates left and right and back and forth.

[Prior art and its problems] The function of forming a double chain stitch in this sewing machine will be explained based on FIG.
As shown in Figure c, looper b, which moves from the right side to the left side, catches the loop of needle thread c that occurs when needle a passes through the fabric and rises.
When needle a rises and the fabric is fed, looper b begins to return from the left side to the right side with a back-and-forth movement (fabric feeding direction), and as shown in Figure d, needle a descends again and looper b On the way back to the right side, needle B encounters looper thread d and catches looper thread d, and as shown in e and f in the same figure, needle a further descends and looper b finishes moving to the right side, completing one action. Thereafter, this action is repeated to create a double chain stitch. Looper b relative to needle a seen from above (throat plate 26 side) during this action
The trajectory is shown in Figure 7.

In the above operation, the looper b carries the needle thread c shown in Fig. 6 a and b, or the looper thread d shown in Fig. 6 d
In order for the needle a to smoothly capture the needle a, it is necessary to set the gaps t and t' between the needle a and the looper b at the time of operation so that a capture error does not occur.

By the way, in a conventional sewing machine of this type, the attachment of the looper to the looper shaft is explained with reference to FIG. It is screwed in place.

However, the gaps t and t' between the needle a and the looper b are determined by the axial movement of the looper b on the looper shaft 9 and the forward and backward movement stroke of the looper b, and conventionally, the stroke adjustment mechanism is Therefore, we are trying to improve the dimensional accuracy and assembly accuracy of each part to achieve the required stroke. Increasing the dimensional accuracy and assembly accuracy will lead to a rise in manufacturing costs.

[Purpose of invention]

For this reason, various means for adjusting the stroke of the forward and backward reciprocating movement of the looper b have been devised in the past, such as Japanese Patent Publication No. 54-39789 and Japanese Patent Application Laid-open No. 54-39789.
-117265, Japanese Utility Model Publication No. 58-23345, Japanese Patent Application Laid-open No. 60-63087, etc.

Although each of these techniques is significant, it is not possible to stop the back and forth movement of the looper b, that is, to create a single chainstitch. Single chainstitch is very advantageous for oversewing.

With the above points in mind, this invention aims to make it possible to adjust the forward and backward reciprocating stroke of the looper, and to also be able to stop the forward and backward movement.

[Means to solve the problem]

In order to achieve the above object, in this invention, the means for reciprocating the looper back and forth has the following configuration.

A cylindrical eccentric cam rotated by a main shaft is rotatably fitted into one end of a longitudinal member supported by an adjustment box attached to the frame, and the other end of the member is fitted in a longitudinal direction perpendicular to the looper. The member is rotatably fixed to the looper shaft of the adjusting box, and the member is supported by the adjusting box by slidably fitting a locking element rotatably provided on the member into a groove of the adjusting box, and the groove is It has an arcuate shape with a radius equal to the distance from the fixed point of the looper shaft of the member to the locking element, and the adjustment box is rotatably supported on the frame by an axis at the center in the longitudinal direction of the groove. With,
It can be fixed by tightening with a screw at the required rotational position.

[Effect]

In this device configured in this way, when the main shaft rotates, the members swing by the eccentric cam. At this time, by appropriately selecting the fixing position of the adjustment box, the member moves back and forth as the locking element slides in the groove of the adjustment box, reciprocating the looper shaft back and forth, and the looper moves back and forth. Move back and forth. That is, since the fixed position of the adjustment box determines the stroke of the forward and backward reciprocating motion of the looper, the stroke of the forward and backward reciprocating motion of the looper is adjusted by adjusting the fixed position.

In addition, if the fixing position is set so that the center of the arc of the groove becomes the fixing point of the looper shaft of the member, the locking element will simply slide within the groove as the member swings, and the locking element will move in the longitudinal direction of the member. does not give the power of That is, single chainstitch is performed without moving the looper back and forth.

〔Example〕

Hereinafter, embodiments of this invention will be described based on the accompanying drawings.

As shown in FIG. 1, a left-right main shaft 1 is driven by a motor (not shown) via a belt 2 and a pulley 3, and the main shaft 2 is driven by a cam 4, a crank 5, etc. , and the hand a moves up and down at the required timing.

For the main shaft 1, as shown in FIG.
are provided orthogonally to each other, and this support shaft 7 is interlocked with the main shaft 1 via various gears 8 . As shown in FIGS. 1 and 2, a looper shaft 9 in the front-rear direction is connected to the support shaft 7 via a cam 10, an eccentric crank 11, a bell crank 12, a bifurcated member 13, etc. When the shaft 7 is driven, the forked member 13 and the like operate as shown by the chain line in FIG. 1, and the looper b attached to the looper shaft 9 via the looper stand 14 moves left and right in accordance with the timing of the needle a. This structure and operation constitute a feeding mechanism for reciprocating the looper b from side to side.

On the other hand, on the left end side of the main shaft 1 (near the looper shaft 9), a feeding mechanism for reciprocating the looper b back and forth is constructed. That is, as shown in FIGS. 2, 3, and 4, a cam 15 is fixed, and a bifurcated member 16 is fitted to this cam 15, and the bifurcated member 16 is inserted through the cam 15 by the rotation of the main shaft 1. The member 16 swings as shown by the chain line in FIG. The base end of the forked member 16 is rotatably supported by a bearing 17 that is rotatably fitted into the looper shaft 9, and the bearing 17 is prevented from moving in the axial direction by a retainer 18 such as an E-ring. . That is, the fork member 16 is rotatable about the shaft 9 and is integral with the shaft 9 in the axial direction.

The looper shaft 9 is rotatably and axially movably supported by a frame A of the sewing machine body, and the frame A has an adjustment box 19 shown in FIG.
is provided rotatably about a shaft 20. A groove 21 is formed on the right side surface of the adjustment box 19, and the shaft 20 is located at the center of the groove 21, and a square block 22 serving as a locking element is rotatably provided on the fork member 16. It is fitted so that it can swing freely, and when the fork member 16 swings, the fork member 1
As the square block 22 slides in the groove 21 corresponding to the degree of inclination of the groove 21 with respect to the longitudinal direction of the forked member 16, the swing point p of the forked member 16 moves in the left-right direction as shown by the chain line in FIG. Move back and forth. Therefore, by adjusting the degree of inclination of the adjustment box 19, the swing point p, that is, the stroke of the forward and backward reciprocating movement of the looper shaft 9 can be adjusted.

An arm 23 is provided at the bottom of the adjustment box 19, and a second
As shown in the figure and FIG. 5, a screw 25 inserted through an arc-shaped elongated hole 24 of the frame A is screwed into this arm 23, and by tightening and fixing the screw 25 at an arbitrary position of the elongated hole 24, The degree of inclination of the groove 21 can be set arbitrarily. That is, the adjustment box 19
By appropriately setting the fixed position of the looper shaft 9, the forward and backward reciprocating stroke of the looper shaft 9 can be adjusted as desired.

Note that the groove 21 is set to have the same curvature as a circle whose radius is the distance from the swing point p of the forked member 16 to the rotation point of the square block 22, and the swing point p of the groove 21
If the adjustment box 19 is set and fixed so as to form an arc-shaped surface centered at , even if the fork member 16 swings, the square block 22 will only slide within the groove 21 and the looper shaft 9 will not move back and forth.

In the figure, the hatched part within the two-dot chain line indicates the sewing machine main body frame A, and 26 is the throat plate.

The embodiment is configured as described above, and now,
When the main shaft 1 is driven by the motor, the needle a moves up and down and the looper b reciprocates left and right and back and forth, as described above, and the needle a, looper b, and their threads c and d as shown in FIGS. 6 and 7. acts to perform double chainstitching.

In this sewing operation, in order to set the gaps t and t' shown in FIG. Adjust the screw position to 9. Further, the adjustment box 19 is set and fixed so that the arcuate surface of the groove 21 is centered on the swing point p, and single chainstitch is performed.

[Effect of idea]

Since this invention is constructed as described above, it is possible to easily obtain the optimum relationship between the needle and the looper during sewing, and also single chainstitch can be performed.

[Brief explanation of the drawing]

Figure 1 is a schematic front view of an embodiment of the sewing machine according to this invention, Figure 2 is a bottom view of Figure 1, Figure 3 is a perspective view of the main parts of Figure 1, and Figure 4 is the same as Figure 1. FIG. 5 is a left side view of the main part, FIG. 5 is a perspective view of the main part of FIG.
FIG. 7 is a diagram showing the relationship between the needle and the looper. 1...Main shaft, 6...Needle bar, 9...Looper shaft, 1
5...cam, 16...bifurcated member, 17...bearing,
18... Stopper, 19... Adjustment box, 21... Groove,
22... Square block, 24... Long hole, 25... Screw, A... Sewing machine body frame, a... Needle, b...
...loopa, c...needle thread, d...loopa thread.

Claims (1)

[Scope of Claim for Utility Model Registration] In a sewing machine that forms a double chain stitch by the cooperation of a needle a that reciprocates up and down and a looper b that reciprocates left and right and front and rear, the back and forth reciprocation of the looper b A sewing machine characterized in that the means has the following configuration. A cylindrical eccentric cam 15 rotated by the main shaft 1 is rotatably fitted into one end of a longitudinal member 16 supported by an adjustment box 19 attached to the frame A, and the other end of the member 16 is The member 16 is rotatably fixed to the looper shaft 9 in the front-back direction perpendicular to the looper b, and the support of the member 16 by the adjustment box 19 is achieved by attaching a locking element 22 rotatably provided to the member 16 to the adjustment box 1.
This is done by slidably fitting into the groove 21 of 9,
The groove 21 is in the shape of a circular arc whose radius is the distance from the fixed point of the looper shaft 19 of the member 16 to the locking element 22, and the adjustment box 19 is connected to the shaft 20 at the center in the longitudinal direction of the groove 21. It is rotatably supported on the frame A by the screws 25, and can be fixed by tightening the screws 25 at the required rotational position.