JPH0133006Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a means for preventing swinging of a needle bar swinging stand during straight stitching in a zigzag sewing machine.

[Conventional technology]

FIG. 2 is a perspective view showing a main part of an example of a needle swinging mechanism of a conventional zigzag sewing machine. Needle bar rocking table 1
The needle bar 4 is supported via the amplitude rods 2 and 3 by a zigzag generating mechanism (not shown) to the needle bar oscillating table 1, that is, the needle bar 4 is supported so as to be able to slide vertically and reciprocally thereon.
is adapted to be swung around a pivot 5 in the direction of the arrow in the figure. The figure shows the state at the straight sewing position ST at the left end of the leftward arrow. 6 is needle bar rocking base 1
A leaf spring that constantly biases the
Reference numeral 7 indicates a needle, and reference numeral 8 indicates a throat plate.The details of the structure 1 and the up-and-down reciprocating drive device for the needle bar are well known and will therefore be omitted.

[Problem that the invention attempts to solve]

However, in such a conventional configuration, when the straight stitch mode is selected, the needle bar 4 moves vertically up and down without swinging, and the needle bar 4 moves vertically in the direction of arrow ST (not shown). The movement is restricted by a cam etc., but it is not restricted in the opposite Z/Z direction. Therefore, when an external force of a certain magnitude is applied in the opposite Z/Z direction, or when the workpiece is thick, when the needle 7 penetrates the fabric during straight stitching, the needle bar oscillating table 1 moves in the Z/Z direction. Run away to needle 7
However, the bent needle sometimes broke. Fig. 3 is an explanatory diagram of this situation, and in reality, if the needle 7 bends and the reaction force causes the rocking table 1 to be displaced in the direction of arrow F in Fig. a, the needle will be bent further and the limit will not be exceeded. be. Further, as shown in FIG. b, after the needle descends and penetrates the cloth W, the needle tip may come into contact with the edge of the needle hole 8a of the throat plate 8 and break (section 7a). Furthermore, in the worst case, this breakage may cause fragments of the needle to collide with the operator's eyes.

In order to solve the above problems, proposals have been made, for example, in Japanese Utility Model Publication No. 45-29322 and Japanese Unexamined Patent Publication No. 54-60050. However, in the former, the main purpose is different from this invention, and at the same time, the elastic deformation of the needle bar rocking table, which causes the above problem, is not solved, and in the latter, the main purpose is different from this invention.
Since the device is connected to the zigzag mode selection knob, the device is connected to the internal operation mechanism of the sewing machine, making it complicated and expensive.

This invention aims to solve the above-mentioned problems by adding an extremely simple and inexpensive external device.

[Means to try to solve problems]

In this invention, lock switching means is provided on the sewing machine frame for releasably restraining the end surface of the lower part of the needle bar oscillating table in the oscillating direction in the straight stitch mode position.

〔Example〕

This invention will be explained below based on examples.
FIG. 1 is a perspective view of essential parts showing an embodiment of this invention. Components that are the same as (corresponding to) the conventional example shown in FIG. 2 above are indicated by the same reference numerals. 10 is a lock switching means (device) 10 according to this invention, which is made of sheet metal material,
A member equipped with a switching lever 11, which is attached to an end surface 12a of the sewing machine frame 12 below the needle bar oscillating table 1 in the Z/Z direction of oscillation of the oscillating table 10 by a pivot 13 around which a surface parallel to the surface 12a is attached. It is installed so that it can rotate in the X direction. An adjusting screw 14 is installed parallel to the pivot 13 at a position apart from the pivot 13 on this sheet metal member by threaded engagement, and when the switching lever 11 is in the indicated arrow ST position, the tip of the screw 14 is connected to the needle bar oscillating base. 1, and comes off from the contact surface 1a at the Z/Z position of the switching lever 11 shown in the arrow, and its threaded side surface touches the upper surface 1 of the sewing machine frame 12.
The position is selected to stop in contact with 2b. Further, one end of a sheet metal member is bent toward the sewing machine frame below the threaded portion 14, and the switching lever 1
A stopper 15 is formed that comes into contact with the lower surface of the sewing machine frame section 12 to restrict the rotation angle when the sewing machine frame section 1 is rotated in the ST direction. The tip of the screw 14 is
The length of the protrusion is adjusted so that the switching lever 11 can be rotated substantially without clearance from the end surface 1a of the needle bar oscillating table 1.

Note that 11a is a protrusion that is used to prevent loose movement by deforming a part of the sheet metal member by coining and creating an appropriate amount of friction between the sheet metal member and the end face of the frame. Further, 16 indicates a threading lever (not directly related to the present invention).

[Effect]

As is obvious from the above configuration, when the sewing machine is in the straight stitch mode, the switching lever 11 is
When fully rotated in the ST direction, it is stopped at a fixed position by the stopper 15, and the tip of the screw 14 prevents the end face 1a of the needle bar swinging base 1 from moving in the upper arrow Z/Z direction of the swinging base. Therefore, even if an external force is applied to the needle 7, the needle bar oscillating base 1 will not be displaced, thereby avoiding the possibility of inducing the bending change of the needle as in the conventional example. It is possible to obtain a straight-line sewing pattern.

Also, when you select the zigzag mode, if you turn the switching lever all the way in the arrow Z/Z direction,
The distal end of the screw 14 is released from the restrictive engagement with the end face 1a of the oscillating table, and the side face of the screw comes into contact with the upper surface of the sewing machine frame 12 and stops, allowing zigzag pattern stitching.

[Other Examples]

Other embodiments of this invention are shown in FIGS. 4 and 5.

FIG. 4 shows a switching device 1 in which a sheet metal bent portion 14A is used in place of the screw 14 in FIG. 1 of the embodiment.
0A and FIG. 5 shows an example of a switching device 10B in which a screw 14B is provided on the end face 1a side of the needle bar rocking table, but these switching means are made of sheet metal members as in each of the above embodiments. Of course, it is not limited to a rotating type, and a sliding type or the like may also be used.

[Effect of idea]

As explained above using each example,
According to this invention, by adding a simple switching means to the outside of the sewing machine that releasably locks the swinging of the needle bar rocking base during straight sewing, it is possible to reduce productivity due to needle breakage during direct sewing. This has the effect of being able to prevent the possibility of deterioration or injury to the human body at a low cost.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a main part showing an embodiment of this invention, Fig. 2 is a perspective view of a main part of an example of a needle swinging mechanism of a conventional zigzag sewing machine, and Fig. 3 a and b are a conventional example. 4 and 5 are perspective views showing other embodiments of this invention. 1... Needle bar rocking table, 1a... End face, 10, 10
A, 10B...Lock switching device. 11...Switching lever, 11a...Protrusion, 12...Sewing machine frame, 13...Pivot, 14, 14B...Screw,
14A...Bending part.

Claims (1)

[Claims for Utility Model Registration] A switching lever 11 is provided rotatably between a lock position and a release position with respect to the end face of the sewing machine frame.
and are arranged between the switching lever and the needle bar rocking base, and when the switching lever is set to the lock position, they engage with each other to lock the needle bar rocking base in the linear mode, and also move the needle bar rocking base to the release position. adjustment screws 14, 14 which disengage the engagement and release the lock of the needle bar rocking base when
b or bent portion 14A, and a stopper 15 that is formed on the switching lever and comes into contact with the lower surface of the sewing machine frame to define the switching lever in the locked position when the switching lever is in the locked position.
A straight-line stitching device for a zigzag sewing machine characterized by the following.