JPS6333878B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an upper feed dog drive mechanism for a sewing machine, particularly for an overcut sewing machine.

(Prior Art) Conventionally, there is a mechanism as shown in FIG. 5 as an upper feed dog drive mechanism for an overlock sewing machine.

The upper feed dog 1 is connected to a back-and-forth moving arm 3 via a swinging rod 2 and moves back and forth, and also moves up and down via the swinging stick 2 by a vertically moving arm 4 that is in contact with the lower surface of the swinging rod 2. , Through this back and forth movement and up and down movement, four movements are performed.
A pressing spring 5 always acts on the upper surface of the swinging rod 2, and presses the swinging rod 2 downward so that it does not play during vertical movement.

(Problems to be Solved by the Invention) For this reason, when the upper feed dog 1 is driven at high speed, the pressing spring 5 jumps and the upper feed dog does not move accurately.

The present invention has been made in view of these drawbacks, and it is an object of the present invention to provide an upper feed swing mechanism for a sewing machine in which the pressing spring does not jump even when the upper feed dog is driven at high speed.

[Structure of the invention]

(Means/effects for solving the problem) This invention connects the forward and backward movable arm and the vertical movable arm to the upper feed swinging rod via a link mechanism, and the upper feed swinging rod is controlled by this link mechanism. The above-mentioned drawbacks are solved by absorbing the rocking motion so that the rocking motion of the upper feed rocking rod is not applied to the pressing spring.

Embodiment 1 An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In the figure, 10 is rotatably supported on the machine frame;
A vertically movable arm 11 swings in the vertical direction (direction of arrow Y) in conjunction with the main shaft (not shown), and is rotatably supported on the machine frame, and swings horizontally (in the direction of arrow X) in conjunction with the main shaft. It is an arm that swings back and forth.

Reference numeral 12 denotes a second link whose one end is rotatably supported by the forward and backward movable arm 11, and the other end is rotatably connected via a pin 13 to an upper feed dog swinging rod 15 having an upper feed dog 14 fixed to its tip. It has been done.

16 is a rotating arm rotatably supported on a pin 17 fixedly supported on the machine frame; 19 is rotatably supported on the rotating arm 16 at one end; and a second link 12 at the other end, which swings the upper feed dog; The third link is a connecting member rotatably supported by the rod 15 and the pin 13, and is a connecting portion between the second link 12 and the upper feed dog swing rod 15. The pin 13 is adapted to move approximately horizontally. 20
21 is a pressure spring that is interposed between the right end of the rotating arm 16 and the machine frame and acts to rotate the rotating arm 16 counterclockwise, and 21 is a buffer made of rubber or the like fixed to the left end of the rotating arm 16. It is a member. 22 is the vertically movable arm 1
These are first links rotatably supported at intermediate portions of the 0 and upper feed swing rods 15, respectively.

(effect) Next, the operation of this invention will be explained.

In a normal feeding state, when the sewing machine is started, the longitudinally movable arm 11 and the vertically movable arm 10 swing in the directions of arrows X and Y.

The swinging motion of the longitudinally movable arm 11 is transmitted to the upper feed swinging rod 15 via the second link 12, and moves the upper feed swinging rod 15 in the front and back direction. Further, the swinging of the vertically movable arm 10 causes the upper feed swinging rod 15 to move in the vertical direction via the first link 22. And this upper feed swinging rod 15
The upper feed dog 14 performs four movements as shown in FIGS. 1 and 2 by combining the movements in the front-rear direction and the up-down direction. At this time, the upper feed swing rod 15 swings between the second link 12, the third link 19, and the first link 22.
Since the pressure is applied via the pressure spring 20, the pressing spring 20 is not displaced, and therefore problems such as jumping do not occur.

As shown in FIG. 3, even when feeding the stepped portion of the cloth, when the upper feed dog 14 is positioned at the step of the cloth, the links 12, 19, and 22 act as the upper feed dog 14 rises, and the feed is not carried out as in the conventional case. When the upper feed dog 14 rises, the pressing spring does not act on the links 12, 19, 2.
2, the presser pressure of the upper feed dog 14 does not become abnormally high when located at the stepped portion, and the fabric can be fed smoothly with appropriate presser pressure.

Example 2 FIG. 4 shows another embodiment.

In this embodiment, the connecting member is slidably supported at one end on the pivot arm 16 and at the other end on the second link 16.
2 and a square piece 24 rotatably supported on the upper feed dog swinging rod 15.

In this embodiment, when the sewing machine is started and the forward and backward movable arm 11 and the vertical movable arm 10 swing, the upper feed dog swinging rod 15 moves four times, and the square piece 24 moves to the pivot arm 16.
Slide. The swinging of the upper feed dog swinging rod 15 is absorbed by the movement of the link 12 and the square piece 24, and no load is applied to the presser spring 5 in the normal feeding state, thereby preventing jumping.

(Effects of the Invention) As described above, according to the present invention, the upper feed dog swinging rod is connected to the longitudinally movable arm 11 and the vertically movable arm 10 via the second link 12 and the first link 22, and Since a connecting member is provided, one end of which is movably supported on a rotating arm that is rotatably supported on the frame, and the other end of which is rotatably supported on the second link and upper feed dog swinging rod, normal sewing machine driving is possible. In this state, the swinging of the upper feed dog is absorbed by the second link connecting member and does not act on the pressure spring, so that jumping of the pressure spring can be prevented.

[Brief explanation of the drawing]

1 to 3 are front views of one embodiment of the present invention, FIG. 4 is a front view of another embodiment, and FIG. 5 is a front view of a conventional example. 10... Up and down moving arm, 11... Back and forth moving arm, 12...
...Second link, 15...Upper feed dog swing rod, 16...
... Rotating arm, 19, 24... Connection member, 20... Pressing spring.

Claims (1)

[Scope of Claims] 1. A vertically movable arm rotatably supported on the machine frame and swinging vertically in conjunction with the main shaft; A front and rear movable arm that swings in the horizontal direction; an upper feed dog swinging rod whose tip is interlocked with the front and rear movable arm via a second link and whose intermediate portion is connected to the vertical movable arm via the first link; A rotating arm rotatably supported by a pin provided in the frame, a pressing spring interposed between the rotating arm and the machine frame, and one end of the rotating arm on the side opposite to the side on which the pressing spring acts with respect to the pin. and connect the other end to the second
An upper feed mechanism for a sewing machine consisting of a link and a connecting member rotatably supported at the connecting part of the upper feed dog swinging rod. 2. The connecting member is comprised of a square piece that is slidably connected to the rotating arm and rotatably supported at the connecting portion between the second link and the upper feed dog swinging rod. The upper feed mechanism of the sewing machine described in scope 1.