JPS642396B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a sewing machine, in particular, as disclosed in Japanese Patent Publication No. 55-8628, a hook needle that moves up and down at a fixed position during the fabric feeding process, and In a sewing machine such as a handle sewing machine that performs chain stitching with a single thread by synchronized cooperation with a looper mechanism that rotates in conjunction with the This device relates to an adjustment device, and its purpose is to allow the stitch loop length to be easily and steplessly changed by displacing the center of swing of a swing lever that moves the needle bar and sewing needle up and down. An object of the present invention is to provide a stitch loop length adjustment device.

Next, one embodiment of the present invention will be described with reference to the drawings.

In the figure, 1 is an embroidery sewing machine configured to form a stitch loop through the cooperative operation of a hooked sewing needle and a looper mechanism. A needle bar is suspended so as to be biased downward by a spring (not shown); 3 is a sewing needle fixed to the lower end of the needle bar 1; 4 is attached to the upper end of the needle bar 1 and projects rearward; This is an interlocking piece.

Reference numeral 5 denotes a support shaft that is rotatably horizontally suspended near the upper end of the sewing machine main body M, and 6 indicates upper interlocking gears 6 and 7 that are fitted onto the support shaft 5 and are fitted together with the support shaft 5. It is an eccentric cylindrical eccentric collar that rotates, and its center position is offset with respect to the axis O2 of the support shaft 5.

Reference numeral 8 denotes a swinging lever that is swingably supported on the support shaft 5 via an eccentric collar 7, and is fitted to the eccentric collar 7 so as to be freely rotatable with the center position of the eccentric collar 7 as the center of swing O1. The swing lever 8 has a front arm 8a extending forward, an upper arm 8b extending rearward and upward, and a lower arm 8 extending downward.
c is formed in a trifurcated shape. The locking pin 9 provided at the front end of the front arm 8a of the swinging arm 8 is connected to the needle bar 1.
The needle bar 1 is locked to the interlocking piece 4 so as to be able to move up and down together, and is connected to the needle bar 1. When the front arm 8a of the swing arm 8 swings upward, the interlocking piece 4 moves upward together with the locking pin 9. When the needle bar 1 moves upward and the front arm 8a swings downward, the interlocking piece 4 moves down together with the locking pin 9, the needle bar 1 moves downward, and as the swing arm 8 swings back and forth, The needle bar 1 moves up and down.

Reference numeral 11 denotes a drive shaft which is rotatable above the support shaft 5 and horizontally suspended in parallel, and is constantly rotationally driven by a main shaft of the sewing machine (not shown); 10 is an upper arm of the swing lever 8 relative to the drive shaft 11; The main cam is fitted opposite to the upper arm 8b, and the upper arm 8 is attached to one side of the main cam.
A cam groove 13 into which a guide pin 12 protruding from the upper end of b is inserted to steadily swing the swing lever 8.
is eccentrically recessed in an annular shape, and when the guide pin 12 is fitted into the cam groove 13, the swing lever 8 repeats a reciprocating swing motion due to the steady rotation of the main cam 10, and the needle bar 1 repeats the swing motion. The sewing needle 3 moves up and down, and the stitch forming operation of the sewing needle 3 is repeated. The main cam 10 also has a guide pin 1.
In order to remove the guide pin 12 from the inside of the cam groove 13 outwardly, a relief groove 14 with an open outer end and communicating with the cam groove 13 is provided. When the main cam 10 is disengaged from the swing lever 8, the linkage between the swing lever 8 and the main cam 10 is released.

15 is an interlocking shaft horizontally suspended below the support shaft 5 in parallel with the support shaft 5, and includes a control motor (not shown);
For example, the rotation is controlled by a pulse motor.

A lower interlocking gear 16 is fitted onto the interlocking shaft 15 in order to mesh with the upper interlocking gear 6 and rotationally drive the support shaft 5, and the interlocking shaft 15 and the support shaft 5 are rotated by the rotation of the control motor. It is rotationally driven synchronously via the upper interlocking gear 6 and the lower interlocking gear 16, and the rotation of the support shaft 5 causes the center position of the eccentric collar 7, that is, the swing center O1 of the swing lever 8, to be moved to the axis of the support shaft 5. Heart O
It can be rotated steplessly around 2.

17 is a sub-cam fitted to the interlocking shaft 15 so as to face the lower arm 8c of the swing lever 8, and includes a convex portion 17a for disengaging the link between the swing lever 8 and the main cam 10; A relief portion 17b is formed to allow the swinging movement of the swinging lever 8 and to dissociate the linkage between the swinging lever 8 and the sub-cam 17. Escape part 17
b is facing the lower arm 8c, the interlocking shaft 1
5 and the guide pin 12 fitted into the cam groove 13 of the main cam 10 when the sub cam 17 is stopped.
is reciprocated by the rotation of the main cam 10, causing the upper arm 8b to repeatedly swing, and the swinging lever 8 to swing back and forth repeatedly to move the needle bar 1 as the front arm 8a swings back and forth. It moves up and down repeatedly, and the sewing operation with the sewing needle 3 is repeated. Further, when the sub-cam 17 is rotated together with the interlocking shaft 15 at the time when the relief groove 14 of the main cam 10 has rotated to the position facing the guide pin 12, the lower arm 8c is pushed by the convex portion 17a of the sub-cam 17. It swings clockwise and stops, and the upper arm 8
b is disengaged from the main cam 10, and the forearm 8a swings above its normal swing range and stops;
The interlocking piece 4 moves upward together with the locking pin 9, and the needle bar 1 is retracted above the normal vertical movement range. In this state, the lower part of the sewing needle 3 is opened, and a space for changing the fabric, etc. can be secured.

When the sub cam 17 is rotated again to the position where the relief portion 17b faces the lower arm 8c, the swing arm 8 and the needle bar 1 return to their original states, and the normal sewing operation is resumed.

When changing the stitch loop length, the interlocking shaft 15 is rotationally driven to connect the support shaft 15 and the eccentric collar 7.
When rotated by a predetermined angle, the center position of the eccentric collar 5 is displaced around the axis O2 of the support shaft 5, and the swing center O1 of the swing lever 8 is displaced in the vertical direction with respect to the horizontal line passing through the axis O2. Due to the reciprocating swinging motion of the swinging lever 8, the range in which the locking pin 9 at the front end of the forearm 8a and the interlocking piece 4 move up and down as a whole shifts in the vertical direction, and the range in which the locking pin 9 at the front end of the forearm 8a and the interlocking piece 4 move up and down moves upward and downward. The top dead center and bottom dead center of the sewing needle 3 both move in the vertical direction while maintaining a substantially constant distance between the top dead center and the bottom dead center. When the sewing needle 3 cooperates with the looper mechanism H provided opposite to the sewing needle 3 to form a stitch loop L, the case where the fabric N advances in the direction in which the hook of the sewing needle 3 protrudes is shown in FIG. 6A. Since the sewing needle 3 is not inserted into the preceding stitch loop L, each stitch loop L is independently planted on the fabric N, and the fabric N is not inserted in the direction in which the hook of the sewing needle 3 protrudes. If the sewing needle 3 moves in the opposite direction, as shown in FIG.
The stitch loops N are inserted into the fabric N in a chained manner. In any case, the stitch loop length l from the base end to the tip of the stitch loop L on the fabric N is determined by the amount of pull when the sewing needle 3 hooks the sewing thread and pulls it up to the top dead center. Therefore, by displacing the swing center O1 of the swing lever 8 in the vertical direction and adjusting the top dead center of the sewing needle 3 in the vertical direction,
The stitch loop length l can be adjusted steplessly.

Next, a second embodiment of the present invention will be described with reference to FIG. Supported in a swingable manner,
The support pin 19 is engaged with a cam groove of an adjustment cam 20 whose rotation is controlled by a control motor so that the support pin 19 is moved in the vertical direction when the adjustment cam 20 rotates, and is further The movable lever 8A is interlocked via a rear arm 8d with a main cam 10A fitted on a drive shaft 11A which is constantly rotated, and the tip of the front arm 8aA is connected to the interlocking piece 4 of the needle bar 1.
The swing lever 8A swings back and forth about the swing center O1 by steady rotation of the main cam 10A, and the interlocking piece 4A moves vertically. By repeatedly moving up and down together with the needle bar 1, the stitch forming operation by the sewing needle is repeated. When the adjusting cam 20 is rotated by a predetermined angle, the swing center O1 of the swing lever 8A is displaced in the vertical direction, and the front end of the swing lever 8A and the top dead center and bottom dead center of the needle bar 1 are almost constant. The distance between the upper and lower dead centers is maintained and the sewing needle moves in the vertical direction, and the length of the stitch loop formed by the sewing needle can be adjusted in a stepless manner.

That is, the present invention supports a swinging lever that swings to vertically move a needle bar of a sewing machine so as to be displaceable via an eccentric means for displacing the center of swing of the swinging lever. By driving the oscillating lever to displace the oscillating center of the oscillating lever, the top dead center of the needle bar is moved up and down, so that the sewing needle pulls the sewing thread to the top dead center and sews. By adjusting the lifting amount of the seam loop when forming the seam loop, the length of the seam loop can be easily and steplessly adjusted for expansion and contraction, and has the effect of simplifying the adjustment operation of the seam loop length. .

[Brief explanation of drawings]

1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a schematic side view of the main parts, FIG. 2 is a side view showing an enlarged adjustment device, and FIG. FIG. 4 is a side view of the adjustment device showing the state in which the swing lever is displaced; FIG. 5 is a side view of the adjustment device of the second embodiment; FIG. 6A, B is a schematic side view illustrating the operation of forming a seam loop. 1...needle bar, 7...eccentric collar, 8,8A...swing lever, 20...adjustment cam, O1...swing center.

Claims (1)

[Claims] 1. A swing lever that swings to move the needle bar of a sewing machine up and down is movably supported via an eccentric means for displacing the swing center of the swing lever, and the eccentric means is driven. A stitch loop length adjusting device for a sewing machine, characterized in that the top dead center of the needle bar is moved up and down when the swing center of the swing lever is displaced.