JPS596788Y2 - sewing machine thread tension regulator - Google Patents

Description

[Detailed description of the invention] (Purpose of the invention) This invention relates to a thread tension device for a sewing machine, and its purpose is to prevent the thread tension dial from falling off from the thread tension device during use or transportation of the sewing machine. That is.

(Prior Art) Conventional thread tension devices have a structure in which a thread tension dial is simply press-fitted or screwed into an adjustment nut screwed onto a thread tension shaft.

However, in the former case, the thread tension dial tends to fall off, and in the latter case, the appearance is unfavorable and also causes an increase in cost.

The present invention has been devised to eliminate the above-mentioned drawbacks, and embodiments of the present invention will be described below with reference to the drawings.

(Structure of the invention) In FIG. 1, reference numeral 1 denotes a thread tension device, a part of which is shown in cross section, and a thread tension outer cylinder 2 is fixed to a sewing machine frame (not shown).

Reference numeral 3 denotes a thread tension shaft fixed to the axial center of the thread tension outer cylinder 2, and a thread tension disc holder 4, a pair of thread tension discs 5, 6, and a spring receiver 7 are installed in the middle of the shaft as is well known. ing.

Reference numeral 8 denotes a dial rotation limiting plate which is fitted into a slotted portion 3a formed in the axial direction at the tip of the thread tension shaft 3 so as to restrict the rotation direction, and reference numeral 9 indicates a dial rotation limiting plate fitted to the thread tension shaft 3 adjacent to the limiting plate. 10 is a thread tension dial press-fitted into a knurled portion 9a formed on the outer periphery of the nut; 10a is a thread tension dial formed on the dial; The stopper is set so as to be able to engage with the projecting piece 8a of the dial rotation limiting plate 8, and restricts the rotation of the thread tension dial 10.

A thread tension spring 11 is wound around the thread tension shaft 3 between the spring receiver 7 and the dial rotation limiting plate 8.

Reference numeral 12 denotes a dial fall prevention member formed from the disc portion 12a and the flat plate-like protrusion portion 12b, and the protrusion portion 12b of this member has a dial rotation limiting plate at the tip of the slotted portion 3a of the thread tension shaft 3. It is fitted adjacent to the right side of 8 so that the direction of rotation is regulated.

Further, the protruding piece 12b has a wedge-shaped crack 12C that opens on the left side, and a flange portion 12d on the left end surface, which is connected to the thread tension shaft 3 and the adjusting nut 9.
It is set so as to protrude into a space 13 formed by a recess 9b formed on the left end surface of.

Thus, the disc portion 12a of the dial fall prevention member 12 is placed in the recess 10b formed on the right end surface of the thread tension dial 10, and the flange portion 12d of the protruding piece 12b is placed in the recess of the adjustment nut 9. 9b.

Reference numeral 14 indicates a scale portion displayed on the right end surface of the disc portion 12a of the dial fall prevention member 12, and reference numeral 15 indicates a scale line engraved on the right end surface of the thread tension dial 10.

The dial drop-off prevention member 12 is attached by press-fitting it into the slotted portion 3a of the thread tension shaft 3 by utilizing the elasticity of the crack 12C of the protrusion portion 12b.

This invention is designed as described above, and the thread tension dial 1
0 to properly align the scale line 15 with the scale part 14 of the dial fall prevention member 12, the adjustment nut 9 will also rotate integrally with the thread tension dial 10, moving the dial rotation limiting plate 8 in the axial direction. The spring pressure of the thread tension spring 11 is adjusted, thereby adjusting the upper thread clamping pressure between the thread tension discs 5 and 6.

At this time, the dial fall prevention member 12 also
It moves only in the axial direction with the rotation of 0.

(Effects of the invention) In the present invention, as described above, the thread tension dial 10 pressed into the adjustment nut 9 is connected to the disc part 12a placed in the recess 10b of the dial and the adjustment nut 9. Recess 9b
is engaged in.

Since the dial is held between the protruding piece 12b having the flange part 12d and the dial fall prevention member 12,
This prevents the thread tension dial 10 from moving in the right direction with respect to the adjustment nut 9. Therefore, there is no risk of the thread tension dial falling off the thread tension device while the sewing machine is in use or being transported, allowing safe and secure sewing. This is a practically useful idea.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view of the thread tension device, Fig. 2 is a view taken along line II-III in Fig. 1, and Fig. 3 is a sectional view taken along line III-III in Fig. 1. , FIG. 4 is a partially exploded perspective view of the thread tension device. In the figure, 3 is a thread tension shaft, 3a and 3b are slotted and threaded parts of the thread tension, 5 and 6 are thread tension discs, 9 is an adjustment nut, 1
0 is a thread tension dial, 11 is a thread tension spring, 12 is a dial drop-off prevention member, and 12 a, 12 b, and 12 d are a disc portion, a protrusion portion, and a flange portion of the dial drop-off prevention member.

Claims (1)

[Scope of utility model registration request] A thread tension shaft 3 equipped with a pair of thread tension discs 5 and 6 and a thread tension spring 11 that applies upper thread clamping pressure to these thread tension discs;
An adjustment nut 9 is screwed onto a threaded portion 3b formed at the tip of the thread tension shaft to adjust the spring pressure of the thread tension spring 11, and a thread tension dial 10 is press-fitted into the adjustment nut.
A protruding piece 12b of a certain dial falling-off prevention member 12 is fitted from the disc part 12a and the protruding piece 12b into the slotted part 3a formed at the tip of the thread tension shaft 3, and the adjustment is performed. The flange portion 12d formed on the projecting piece 12b of the dial drop-off prevention member 12 is engaged with the left end surface of the nut 9, and the disc portion 12 of the dial drop-off prevention member 12 is engaged with the right end surface of the thread tension dial 10. A thread tension device for a sewing machine, in which the thread tension dial 10 is supported by the dial fall prevention member 12.