JPH019500Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a width adjustment mechanism in a zigzag sewing machine of the type in which zigzag stitching is performed by a zigzag cam.

Prior Art The zigzag mechanism of this type of zigzag sewing machine generally includes a zigzag cam that rotates in conjunction with the main shaft, a follower that follows the cam, and a slider that is slidably attached to an adjustment box that swings in conjunction with the movement of the follower. It consists of a rod that connects the slider and needle bar support, and a manual operation mechanism that includes an operating lever that is connected to the slider.The needle bar support is controlled by adjusting the changes in the cam surface of the zigzag cam through a follower, adjustment box, rod, etc. The amount of oscillation, that is, the width of the oscillation, can be adjusted using the manual operation mechanism by sliding the slider along the adjustment box via the operating lever, until it reaches the center of oscillation. This is done by changing the spacing.

Problems that the invention aims to solve As mentioned above, in order to adjust the swing width, the conventional mechanism is equipped with an adjustment box that swings in conjunction with the movement of the follower, and the slider attached to this box is operated by a manual operation mechanism. The structure is relatively complicated. In addition, when performing straight stitches, the slider is positioned at the center of the swinging box, but since the swinging box always swings at a constant width, the slider is not positioned at the center of the swinging box. Also, the swinging of the swinging box affected the needle bar through the rod, and it was inevitable that the needle bar would move slightly, and as a result, it was impossible to form a clean straight stitch.

Means for Solving the Problem A regulating means is provided that engages with a follower that follows the zigzag cam to restrict the movement of the zigzag cam from a higher surface toward a lower surface midway, and the engagement position of the means with the follower is Allows for radial adjustment.

The regulating means may include, for example, an eccentric cam that is concentric with the zigzag cam and is rotatably operated by a manual operation member, a protrusion protruding from a slide plate that slides in the radial direction by the manual operation member, or a protrusion provided on the manual operation member. It consists of a part of a bell crank-shaped lever that pivots.

The follower may be connected to the needle bar support by a link, or may be provided integrally with an arm fixed to the needle bar support. In the latter case, the movement of the follower that follows the zigzag cam is directly transmitted to the needle bar support without going through an intermediary such as a link, so changes in the cam surface of the zigzag cam are accurately transmitted to the needle bar. It becomes easy.

Embodiment In FIGS. 1 to 3, a boss portion 6 of an amplitude control cam 5, which is integrated with an operation knob 4, is loosely fitted concentrically to a cam shaft 3 of a zigzag cam 2 that rotates in conjunction with a main shaft 1. The inner edge 7a of the arc-shaped cam groove 7 formed on the amplitude control cam 5 preferably has one end having the same diameter as the lower surface 2a of the zigzag cam and the other end having the same diameter as the higher surface 2b. The outer edge 7b is formed to have a diameter slightly larger than that, and the outer edge 7b preferably has a diameter that is large enough to prevent the follower 8 that fits loosely into the cam groove 7 from engaging with the high surface 2b.
The cam groove is formed so that the follower 8 that engages with the cam groove is restricted from the outside so that the follower does not move away from the higher surface, and the other end of the cam groove is formed so that the follower 8 cannot move in the radial direction. Ru. The follower 8 is fixed to the end of an inverted L-shaped arm 10 whose one side is fixed to the needle bar support 9, transmits changes in the cam surface of the zigzag cam 2 to the needle bar support 9, and is supported by the support so as to be movable up and down. Swing the needle bar 11 that is currently in use from side to side. In the figure, reference numeral 12 denotes a spring that biases the needle bar support 9 clockwise in the figure, so that the follower 8 comes into elastic contact with the zigzag cam 2 via the arm 10. 14 is a throat plate. Note that the needle bar moves up and down in conjunction with the main shaft 1 in a known manner.

In this embodiment, the swing width is adjusted using the operating knob 4.
This is done by operating the swing width control cam 5. That is, when the maximum groove width at one end of the cam groove corresponds to the follower 8, the follower 8 is located on the lower surface 2a.
When the swing width reaches its maximum, and the swing width control cam 5 is turned counterclockwise in the figure, it is limited by the inner edge 7a and the swing width gradually becomes smaller. When the swing width control cam 5 is further turned counterclockwise in the figure and the contact point of the follower coincides with the diameter of the higher surface 2b, the follower stops and the swing width becomes 0. As described above, if the minimum groove width at the other end of the cam groove is set to such a width that the follower cannot move in the radial direction, the follower will be in a fixed state and strict straight stitching will be performed.

In the embodiment described above, the amplitude control cam is configured as a grooved cam having an arc-shaped cam groove, but it may also be configured as a plate cam with a cam surface on the peripheral edge.

In the embodiment shown in FIG. 4, the cam shaft 3 of the zigzag cam 2 is slidably fitted into one of the two parallel long holes 15, and the pin 17 fixed to the frame is fitted into the other 16. A slide plate 18 that can move only in the radial direction of the zigzag cam
A tongue piece 19 that engages with the follower 8 and restricts the radial inward movement of the follower is provided in a protruding manner.As a manual operation mechanism for sliding the slide plate 18, for example, the slide plate It is also possible to adopt a mechanism in which a pinion that easily engages with the operation knob is attached, or a mechanism in which a cam that engages with the slide plate is mounted on the operation knob.

In the embodiment shown in FIG. 5, the movement of the follower is regulated by one end face of a bell crank-shaped lever 21 whose intermediate portion is pivoted to the frame, and an operation knob (not shown) is provided at the other end face. An eccentric cam 22 which is rotated by the lever is engaged, and the lever 21 is pivoted by the rotation of the cam.

Effects of the invention The structure is simpler than the conventional one, in which the movement of the follower is transmitted to the adjustment box, and the swing width can be changed by moving a slider attached to the adjustment box, and the swing width adjustment mechanism is simpler. Even though the needle bar support is provided with a follower, the follower can be provided integrally with the needle bar support, and therefore the movement of the follower can be directly transmitted to the needle bar support. Furthermore, since the follower does not move when the oscillation width is 0, the needle bar does not move slightly, and therefore it is possible to obtain clean straight stitches.

[Brief explanation of the drawing]

Fig. 1 is a front view of the main mechanism of a zigzag sewing machine equipped with a swing width adjustment mechanism according to the present invention, Fig. 2 is a plan view of the same, Fig. 3 is an exploded perspective view of the main part, and Fig. 4 is a front view of the main mechanism of a zigzag sewing machine equipped with a swing width adjustment mechanism according to the present invention. FIG. 5 shows a front view of the main part of another embodiment of the adjustment mechanism, and FIG. 5 shows a front view of the main part of still another embodiment. 1...Main shaft, 2...Zigzag cam, 3...Cam shaft, 4...Operation knob, 5...Swing width control cam, 7...
...Cam groove, 8...Follower, 9...Needle bar support,
10...Arm, 18...Slide plate, 19...
Tongue piece, 21... Bell crank-shaped lever, 22...
eccentric cam.

Claims (1)

[Claims for Utility Model Registration] (1) A zigzag sewing machine having a zigzag cam that rotates in conjunction with a main shaft, and a follower that engages with the cam, so that the movement of the follower can be transmitted to the needle bar. , the regulation is capable of engaging with a follower that moves radially inward from the high surface 2b of the zigzag cam 2 toward the low surface 2a, and the engagement position is configured to be adjustable in the radial direction by a manual operation mechanism. A swing width adjustment mechanism having means. (2) The swing width adjustment mechanism according to claim 1, wherein the regulating means is a swing width control cam 5 concentric with a zigzag cam rotated by a manual operation mechanism. (3) The swing width adjustment mechanism according to claim 2, wherein the swing width control cam is a grooved cam whose groove width gradually changes. (4) The swing width adjustment mechanism according to claim 3, wherein the minimum groove width portion is formed to such a groove width that the fitted follower cannot move in the radial direction. (5) The swing width adjusting mechanism according to claim 1, wherein the regulating means is a tongue piece 19 projecting from a slide plate 18 that is movable only in the radial direction. (6) The swing width adjusting mechanism according to claim 1, wherein the regulating means is one end surface of a bell crank-shaped lever 21 pivoted by a manual operation mechanism.