JPH0510792Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a looper drive mechanism for a sewing machine in which the looper makes an elliptical motion and cooperates with the needle to form a double chain stitch.

Prior art One of the looper drive mechanisms of this type of sewing machine
47-2981, namely, a crank supported on a fixed shaft and oscillating around the axis of the fixed shaft in conjunction with the main shaft, and supported pivotally on the crank by a pin parallel to the fixed shaft. A square piece, a looper shaft that is rotatably supported perpendicular to the fixed shaft and slidable in the axial direction and swings in conjunction with the main shaft, and a looper shaft that is fixed to the shaft end of the looper shaft and is There is one that consists of a part that sandwiches the square piece with the end face of the shaft. According to this mechanism, the line of action of the force for sliding the looper shaft in the axial direction coincides with or almost coincides with the axis of the looper shaft, so the force that presses the looper shaft against the bearing is eliminated or almost eliminated. The amount of sliding contact between the swinging looper shaft and the square piece is reduced, and as a result, the torque of the sewing machine is reduced and the load on each part is reduced, resulting in a lightweight sewing machine with less wear and tear. Since the shaft that supports the crank does not swing, it has the effect of further reducing the load, but the needle avoidance momentum in the short axis direction of the elliptical movement performed by the looper is cannot be adjusted accordingly.

Japanese Patent Publication No. 54-39789 discloses a looper shaft that is supported rotatably and slidably in the axial direction and swings in conjunction with the main shaft, and a looper shaft that is supported orthogonally to the looper shaft and has a looper shaft at one end. It consists of a swing shaft with a sliding arm, a rod with one end fitted onto an eccentric cam fixed to the main shaft, and the other end fixed to a crank fixed to the swing shaft so that its position can be adjusted. By adjusting the axis attachment point with the crank at the end in the radial direction of the crank, the elliptical locus drawn by the looper can be adjusted in the minor axis direction according to the thickness of the needle, that is, the needle avoidance momentum can be adjusted. A method is shown in which scooping can be carried out without changing the scooping position, but in this case, the difference between moving the attachment point between the other end of the rod and the crank closer to the axis of the swing shaft and moving it further away from the rod is different. As the inclination is different and the eccentric cam begins to rotate, the phase of the swing axis shifts, and the timing of the needle avoidance movement shifts. As a result, the shape of the elliptical locus drawn by the looper changes, which has an unfavorable effect on sewing.

Problems to be Solved by the Invention The present invention attempts to make it possible to adjust the needle avoidance momentum in accordance with the thickness of the needle in the former type of looper drive mechanism; If this method is adopted, the phase of the crank is shifted and the timing of the needle avoidance movement is changed, which has an undesirable effect on sewing. In a mechanism consisting of an eccentric cam fixed to the main shaft, a rod with one end fitted onto the eccentric cam and the other end pivotally attached to the crank, and the crank, the same applies when changing the mounting angle of the eccentric cam with respect to the main shaft. cause misalignment.

An object of the present invention is to enable the needle avoidance movement amount to be adjusted in the former type of looper drive mechanism without changing the timing of the needle avoidance movement or the scooping position of the needle thread loop.

According to the present invention, as shown in the figure, there is a looper shaft 1 which is rotatable and axially slidable and is supported horizontally, and a fixed shaft 8 which is orthogonal to the looper shaft 1. A crank 9, 33, 41, 51, 61 that is supported and swings around the fixed shaft 8 in conjunction with the main shaft, and a crank that is supported with respect to the crank so that its position can be adjusted in a direction orthogonal to the fixed shaft 8. Pins 23, 35, 6
5 and the crank pin 23, 35, 65 is fixed to the shaft end of the looper shaft 1, and the shaft end surface of the looper shaft is connected to the crank pin 23, 35, 65.
A looper drive mechanism is provided in which the direction in which the crank pins 23, 35, and 65 are adjusted is vertical when the looper 26 is in the position for scooping up the needle thread loop.

In order to support the crank pin on the crank, the crank pin may be attached to a bracket attached to the crank, or may be attached directly to the crank. In any case, it is preferable to support the fork-shaped portion at both ends rather than to support it in a cantilevered manner. This is because the mounting condition is stable and there is no wobbling during sewing machine operation.

In order to finely adjust the position of the crank pin, the crank may be provided with an adjustment groove parallel to the fixed shaft, and the bracket may be provided with an eccentric pin that fits into the adjustment groove. Furthermore, it is desirable that the bracket or crank pin only move vertically during adjustment, and not move or rotate laterally, and that the set screws or nuts used to secure the bracket or crank pin should be ,
It is desirable that the sewing machine face an opening provided in the sewing machine frame so that it can be directly operated through the opening with a tool such as a wrench or a screwdriver. This is because adjustments can be made easily and reliably.

Operation Assume that the looper 26 is now in a position where it scoops up the needle thread looper. As shown by the solid line in FIG. 7, the crank pin 23 is movable in the vertical direction along the shaft end surface of the looper shaft 1.
The distance between the fixed shafts 8, that is, the radius of rotation changes. The amount of rocking of the crank pin 23 changes as shown by the dotted line when the crank pin 23 is fixed in the upper position and the crank is rocked, and when it is fixed in the lower position and the crank is rocked. Therefore, the stroke of the looper shaft 1, that is, the looper 26
The needle avoidance momentum changes. In the illustrated example, as the crank pin 23 is adjusted, the swinging range of the crank pin 23 also shifts slightly to the left and right, but since the adjustment is made without rotating the crank, the phase and amount of swing of the crank do not change. The crank pin 23 only rotates a little, and since the crank pin 23 is not an eccentric pin, the phase and therefore the timing of the needle avoidance movement will not be shifted.
Moreover, as shown by the solid line in the figure, the crank pin 23
simply moves along the end surface of the looper shaft 1,
There is no displacement in the axial direction of the looper shaft, so the looper shaft 1
remains stationary, and the position where the looper 26 scoops up the needle thread looper does not change.

If the bracket 15 to which the crank pin 23 is attached is provided with an eccentric pin 18 that fits into the adjustment groove 14 of the crank 9, the position of the crank pin 23 can be finely adjusted within the range of eccentricity by turning the eccentric pin. Ru.

Embodiment In FIGS. 1 and 2, a looper shaft 1 is supported rotatably and slidably in the axial direction, and swings around a fixed shaft 2 parallel to the looper shaft 1 in conjunction with a main shaft (not shown). lever 3 fixed to the looper shaft 1, and a rod 5 connecting the lever 3 and lever 4.
The rod 5 is pivotally supported on a pin 6 fixed to the lever 4 so that it can not only rotate but also slide. It is designed to allow for directional movement. A crank 9 is rotatably supported on a fixed shaft 8 orthogonal to the looper shaft 1, and as the main shaft rotates, an eccentric cam (not shown) is fixed to the main shaft, one end of which is externally fitted onto the eccentric cam, and the other end of which is attached to the eccentric cam. is connected to the crank 9 via the rod 11 which is pivoted to the crank 9.
is adapted to swing around a fixed shaft 8.
A mounting surface 13 parallel to the fixed shaft 8 is formed on the crank 9, and an adjustment groove 14 parallel to the fixed shaft 8 is formed on the upper part of the mounting surface. It is arranged so that it forms a vertical plane. A bracket 15 that is slidably fitted in the vertical direction while being joined to the mounting surface 13
is fixed so that its position can be adjusted within the range of the vertical hole 12 by a tightening screw 16 screwed into the mounting surface of the crank 9 through the vertical hole 12, and an adjustment screw 17 is provided above the vertical hole. rotatably mounted,
An eccentric pin 18 provided on the adjustment screw 17 fits into the adjustment groove 14. And these tightening screws 16
The adjustment screw 17 faces an opening 19 formed in a machine frame 20 at the rear of the sewing machine, and can be operated with a tool such as a screwdriver or wrench through the opening 19 when the lid 21 is removed.

Reference numeral 23 denotes a crank pin whose both ends are rotatably supported by both fork-shaped arms 24 of the bracket 15, and is sandwiched between the crank pin guide 25 fixed to the shaft end of the looper shaft 1 and the looper shaft 1. , 26 is designed to prevent movement of the looper shaft 1 in the axial direction, and has a cut-out flat surface on both sides and is in surface contact with the end surface of the looper shaft and the crank pin guide 25. This is a looper fixed to a looper stand 27 attached to one end of the looper shaft 1.

The present embodiment is constructed as described above, and when adjusting the needle avoidance movement of the looper 26 according to the thickness of the needle, the lid 21 is removed and the tightening screw 16 is first tightened using a tool such as a screwdriver or wrench. Loosen the attachment to the extent that the bracket 15 can move easily. At this time, it is not necessarily necessary to keep the attachment surface 13 vertical at the position where the looper 26 scoops up the needle thread loop, but it is preferable to carry out the work with the attachment surface vertical. This is because the work becomes easier. After the bracket 15 is made movable, adjust the adjustment screw 1.
7 rotation operations are performed. As a result, the bracket 15 moves up and down along the mounting surface 13, and the distance between the crank pin 23 and the fixed shaft 8, that is, the rotation radius of the crank pin 23 changes. Therefore, the amount of swing of the crank pin 23 changes, the stroke of the looper shaft 1 changes, and the needle avoidance momentum of the looper 26 changes. However, when the looper 26 is in the position to scoop up the needle thread loop, the mounting surface 13 is vertical. As described in the section on the operation above, the position at which the needle thread loop is scooped does not change, and the timing of the needle avoidance movement does not shift.

According to this embodiment, in addition to the above, fine adjustment of the crank pin 23 is facilitated by rotating the adjustment screw 17, and when fixing with the tightening screw 16 after adjustment,
Since the bracket 15 is fitted onto the crank 9 and does not shift horizontally or vertically, the crank pin 23 can be adjusted reliably, and the tightening screw 1
6 and adjustment screw 17 face the opening, the lid 21
The crank pin 23 can be easily adjusted by removing the screwdriver and inserting a tool such as a screwdriver or wrench, and because the adjustment described above eliminates the need to readjust other parts. Furthermore, since both ends of the crank pin are supported by brackets, the mounting condition is stable and the crank pin does not wobble during operation of the sewing machine.

In the embodiment shown in FIG. 3, a mounting shaft 32 that projects vertically from a bracket 31 is fitted into a crank 33 and fixed with a set screw 34.

In this embodiment, the structure is simpler than the above-mentioned embodiments since there is no adjustment screw 17.

In this embodiment, the bracket 31 can easily rotate when the set screw 34 is loosened. This problem,
This problem can be solved by forming a key or a flat contact surface on the mounting shaft 32 to prevent rotation.

In the embodiment shown in FIG. 4, a vertical dovetail groove 42 is formed in the crank 41 and a slider 43 is inserted thereinto.
A screw 44 protruding from the slider 43 is passed through a bracket 45, and a nut 46 is screwed into the protruding end of the screw 44 to press the slider 43 onto the crank 41 and fix it. Compared to the embodiment shown, there is an advantage that there is no risk of the bracket 45 rotating.

In the embodiment shown in FIG. 5, a long hole 55 in the vertical direction is provided in the mounting portion 54 of the bracket 53 which is slidably fitted into the flat groove 52 in the vertical direction of the crank 51. Bracket 5
It is designed to be fixed to 3.

In this embodiment, since the set screw 56 is oriented horizontally, it is particularly convenient when the opening is provided horizontally.

In the embodiment shown in FIG. 6, a longitudinal long hole 62 is formed in a crank 61, a flanged pin 63 is fitted therein, and a nut 64 screwed into the protruding end is tightened and fixed to form a cantilever shape. Attachment: The crank pin 65 is rotatably fitted onto the flanged pin 63.

In this embodiment, since the crank pin 63 is directly supported by the crank 61, the structure is the simplest among the above embodiments.

Effects of the invention According to the looper drive mechanism of the sewing machine according to claims 1 and 9, the amount of needle avoidance movement can be adjusted according to the thickness of the needle without changing the scooping position of the needle thread loop by the looper or the timing of the needle avoidance movement. I can do it.

In the looper drive mechanism of a sewing machine according to claim 2,
Since both ends of the crank pin are supported by brackets, the mounting condition is stable and the crank pin does not wobble while the sewing machine is running.

According to the looper drive mechanism of the sewing machine according to claim 3,
Fine adjustment of the crank pin is facilitated by rotating the adjustment screw.

In the looper drive mechanism of the sewing machine according to the fourth aspect, since the bracket is fitted to the crank so as to be slidable in the vertical direction, there is no possibility of shifting in the horizontal direction during adjustment, especially when using the adjustment screw. Since it does not shift in the vertical direction, the crank pin can be adjusted easily and reliably. Moreover, since the tightening screw faces an opening provided at the back of the sewing machine, the tightening screw can be easily operated by removing the cover and inserting a tool through the opening, and the crank pin can be easily adjusted.

According to the looper drive mechanism of the sewing machine according to claim 5,
The structure is simplified since it does not have a crank pin fine adjustment mechanism.

In the looper drive mechanism of the sewing machine according to claims 6 and 7, since the bracket does not move or rotate in the lateral direction, adjustment can be easily and reliably performed.

The looper drive mechanism of a sewing machine according to claim 8,
Since the crank pin is directly supported by the crank, the structure is extremely simple.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of a looper drive mechanism that is an embodiment of the present invention, Fig. 2 is a sectional view of essential parts of the mechanism,
3 to 6 are exploded perspective views of main parts of different embodiments, and FIG. 7 is an explanatory view of the operation. 1... Looper axis, 8... Fixed axis, 9, 33, 4
1,51,61...Crank, 12...Vertical hole, 1
3...Mounting surface, 14...Adjustment groove, 15, 31, 4
5, 53...Bracket, 16...Tightening screw, 1
7... Adjustment screw, 18... Eccentric pin, 21...
Lid, 23, 35... Crank pin, 25... Crank pin guide, 26... Looper, 32... Mounting shaft, 42... Dovetail groove, 43... Slider, 46...
...nut, 55, 62...long hole, 63...flange pin.

Claims (1)

[Claims for Utility Model Registration] (1) A looper shaft 1 that is rotatable and slidable in the axial direction and is supported horizontally, and a fixed shaft 8 that is perpendicular to the looper shaft 1 and interlocked with the main shaft. The cranks 9, 33, 41, 51, which swing around the fixed shaft 8,
61, crank pins 23, 35, 65 which are supported with respect to the crank so that their positions can be adjusted in a direction orthogonal to the fixed shaft 8, and which are fixed to the shaft end of the looper shaft 1 and are connected to the shaft end surface of the looper shaft. The crank pin guides 25 sandwich the crank pins 23, 35, 65, and when the looper 26 is in the position to scoop up the needle thread loop, the crank pins 23, 35, 6
A looper drive mechanism of a sewing machine in which the direction of adjustment of No. 5 is vertical. (2) Looper 2 is installed on cranks 9, 33, 41, and 51.
6 is in the position to scoop up the needle thread loop, the brackets 15, 31, 45, 53 are fixed so as to be vertically adjustable, and the crank pins 23, 35 are attached to the fork-shaped arms 24 of the bracket at both ends. The looper drive mechanism for a sewing machine according to claim 1, wherein the looper drive mechanism is pivotally supported. (3) The crank 9 has an adjustment groove 14 parallel to the fixed shaft 8.
3. A looper drive mechanism for a sewing machine according to claim 2, wherein an eccentric pin 18 is rotatably supported in the bracket 15 and fits into the adjustment groove 14. (4) A mounting surface 13 is formed on the crank 9. With the bracket 15 connected to the mounting surface 13, the bracket 15 is fitted to the crank 9 so as to be slidable in the vertical direction, and fixed to the crank 9 through the vertical hole 14. The sewing machine according to claim 2 or 3, wherein the sewing machine is fixed by a tightening screw 16, the tightening screw 16 faces an opening 19 provided at the rear of the sewing machine, and the lid 21 is detachably attached. Looper drive mechanism. (5) A mounting shaft 32 is provided vertically protruding from the bracket 31 and is inserted into the crank 33, and a set screw 34 is inserted into the bracket 31.
3. The looper drive mechanism for a sewing machine according to claim 2, wherein the looper drive mechanism is adapted to be fixed at the opening 19 provided at the rear of the sewing machine, and the set screw 34 faces the opening 19 provided at the rear of the sewing machine, and the lid 21 is detachably attached. (6) A dovetail groove 42 is formed in the crank 41, and a screw 44 protruding from a slider 43 fitted into the dovetail groove 42 is passed through a bracket 45, and a nut 46 is screwed onto the protruding end thereof. 3. A looper drive mechanism for a sewing machine according to claim 2, wherein the nut 46 faces an opening 19 provided at the rear of the sewing machine and the lid 21 is removably attached. (7) A flat groove 52 is formed in the crank 51, into which a mounting portion 54 of a bracket 53 is slidably fitted, and a set screw 56 is fixed to the bracket 53 through a long hole 55 in the vertical direction of the mounting portion 54. A looper drive mechanism for a sewing machine according to claim 2. (8) A longitudinal elongated hole 62 is formed in the crank 61, and a crank pin 65 is fitted into and pivotally supported by a pin 63 which is fitted into the elongated hole and fixed in a position-adjustable manner. Sewing machine looper drive mechanism. (9) A looper shaft that can rotate and slide in the axial direction, is supported horizontally, and a fixed shaft that is orthogonal to the looper shaft, and swings around the fixed shaft in conjunction with the main shaft. a crank; a crank pin supported so that the distance between the crank and the fixed shaft can be adjusted along a plane parallel to the fixed shaft; and a crank pin fixed to the shaft end of the looper shaft and fixed to the shaft end of the looper shaft; A looper drive mechanism for a sewing machine, comprising a crank pin guide that sandwiches the crank pin, and the position of the crank pin is adjusted along a vertical plane when the looper is in a position for scooping up a needle thread loop.