JPS60865Y2 - Rotary hook for sewing machine - Google Patents

Description

[Detailed explanation of the idea] This invention relates to an improvement of a rotary hook for a sewing machine.

In a conventional rotary hook for a sewing machine, the inner hook, the outer hook, and the spring plate fixed to the outer hook are made of metal, and the parts constituting the rotary hook, such as the outer hook and the leaf spring, are fixed with screws.

However, because the inner pot is rotatably fitted to the outer pot,
During use, metal parts may rub against each other, causing noise or
The service life is short due to expansion due to frictional heat, and in particular, those with metal parts fixed with screws have problems such as poor balance, inhibiting high-speed rotation, and increasing the failure rate.

Therefore, it is known that the part of the inner pot that slidably fits into the groove on the inner peripheral surface of the outer pot is made of synthetic resin. is not sufficient, and conventional rotary pots have not taken into consideration the elimination of screws.

This idea was made based on the above-mentioned circumstances, and involves fitting a middle ring made of fluororesin onto the opposing ends of a metal upper ring and a metal lower member, so that the upper ring and lower member are concentrically connected. By connecting the outer circumferential part of the middle ring to the inner circumferential surface of the outer hook and slidingly fitting it into the groove provided on the inner circumferential surface of the outer hook, the workability of the components of the inner hook is good, and the assembly of the components is also easy. Although the productivity of the inner pot is high, the adverse effects of noise generation and thermal expansion can be eliminated without using lubricating oil.

Furthermore, this invention fixes the spring plate to the outer hook without using screws or their screw holes by welding the spring plate to the outer circumferential surface of the outer hook, thereby achieving a sufficient thread tension effect when thread is drawn. At the same time, a cylindrical boss portion protruding from the bottom of the outer pot is provided with cuts along the axial direction at multiple locations in the circumferential direction, and a taper is provided on the outer circumferential surface of the boss portion such that the diameter becomes larger on the tip side, By fitting a cylindrical tightening member with a taper corresponding to this taper on the inner circumferential surface to the boss part, it is possible to easily attach and detach the outer hook to the rotating shaft system, and to attach the outer hook to the rotary shaft system. This design eliminates the use of screws, has a well-balanced rotation of the outer pot, enables high-speed rotation, maintains a long service life, and reduces the number of breakdowns.

An embodiment of this invention will be described below with reference to the drawings.

The rotary hook for a sewing machine of this embodiment is composed of an inner hook, an outer hook, and a spring plate.

The inner pot includes an upper ring 1, a middle ring 2, and a lower member 3.
The lower end of the outer circumferential surface of the upper ring 1 and the upper end of the outer circumferential surface of the lower member 2 are made of metal, and diagonal grooves 11 and 31, each having a deep triangular cross section on the side away from the end, are provided, respectively. The middle ring 2 is made of fluororesin and has upper and lower oblique grooves 2L22 each having a triangular cross-section and a deep triangular cross section on the inner peripheral surface and the lower end thereof.

The inner pot has a middle ring 2 in a diagonal groove 11 at the lower end of the upper ring 1.
Press it onto the upper peeling groove 21 of the lower member 3, and
1 to the lower diagonal groove 22 of the middle ring 2, the diagonal groove 11 and the upper groove 21, and the diagonal groove 31 and the lower diagonal groove 22 are closely engaged, respectively, and the upper ring 1 and the lower member 3 are opposed to each other. A middle ring 2 is fitted to the end, and an upper ring 1 and a lower member 3
are concentrically connected.

The outer pot 4 is made of metal with a groove 41 formed along the inner peripheral surface in the circumferential direction, and the outer circumference of the upper ring l and the lower member 3 of the inner pot to which each component is connected as described above. An outer peripheral portion of the middle ring 2 protruding from the surface is closely and slidably fitted into the groove 41.

As mentioned above, since the inner hook is rotatably fitted and supported by the outer hook 4, the outer hook 4 rotates on the middle ring 2 made of fluororesin as an orbit when rotating.

The middle ring 2 made of fluororesin has a small coefficient of friction and can not only withstand high temperatures, but also does not require lubricating oil even if it comes into contact with the wall surface of the groove 41 of the metal outer hook 4 during rotation. It can rotate at high speed without making any noise while rotating.

The cylindrical post portion 42 protrudes from the bottom of the outer pot 4 in the axial direction, and three slits 43 are provided at 120 degrees to each other in the circumferential direction.
are formed along the axial direction with an angular spacing of .

A taper is formed on the outer circumferential surface of the boss portion 42, and the diameter becomes larger on the tip side, and the boss portion 42 has a taper nut, that is, a cylindrical tightening member 5, which has a taper corresponding to this taper on the inner circumferential surface. They are fitted to be movable in the axial direction.

Further, a spring plate 6 having a sharp tip for hooking a thread is fixed to the outer peripheral surface of the outer hook 4 by high-frequency welding.

To use the rotary hook of this embodiment, with the cylindrical tightening member 5 positioned at the distal end of the boss 42, the boss 42 is attached to the rotating shaft system of each type of industrial or household sewing machine. Fit,
By moving the tightening member 5 to the tip side of the boss portion 42, the diameter of the boss portion 42 is reduced and the outer hook 4 is fixed to the rotating shaft system.

Therefore, there is no need for a set screw or the like, and the boss portion 4 can be easily
2 can be fixed to the rotating shaft system, and the outer hook 4 can be easily attached and detached.

When the outer hook 4 is rotated, the thread is hooked at the tip of the spring plate 6 to achieve the action of a sewing thread.
Because there are no screws or screw holes and the rotational balance of the outer hook 4 is good, the rotational speed per minute can be more than doubled compared to conventional ones.

As explained above, according to this invention, the component parts of the inner pot have good workability and are easy to assemble, and the inner pot is easy to assemble. Since it is slidably fitted into a groove on the inner circumferential surface of the outer hook, it is possible to prevent the generation of noise and the adverse effects of thermal expansion. Since the tightening member is fitted in a tapered manner, the outer hook can be easily attached to and removed from the rotating shaft system, and since there are no screws or screw holes in the outer hook,
It is possible to provide a rotary hook for a sewing machine that has good rotational balance, can be rotated at high speed, and has a long life.

[Brief explanation of the drawing]

Figure 1 a''-c shows an upper ring according to an embodiment of this invention, a is a plan view, b is a partially cutaway front view, C is a bottom view of the main part, and Figures 2 a and b are views of this upper ring. The middle ring according to an embodiment of the invention is shown, a is a partial plan view, b is a partially cutaway front view, and the third Innoshima is a lower member according to an embodiment of the invention, a is a partial plan view, and b is a partially cutaway front view. Fig. 4a and b are a plan view of the outer pot according to an embodiment of this invention, and Fig. 4b is a partially broken front view of the tightening member. FIGS. 5a and 5b show a spring plate according to an embodiment of the invention, a is a developed view, b is a plan view, and FIGS. The pot is shown, where a is a side view of the main part and b is a partially cutaway front view. 1... Upper ring, 2... Middle ring, 3... Lower part. Parts, 4... Outer pot, 5.
...Tightening member, 6...Spring plate, 11.2
1. 22.31... diagonal groove, 41...
Concave groove, 42... Cylindrical boss portion, 43...
Kiriwari.

Claims (2)

[Scope of utility model registration request] (1) In a rotary hook for a sewing machine in which an inner hook is rotatably fitted into a metal outer hook, a metal upper ring and a metal lower member of the inner hook are attached to opposing ends of the fluorine hook. A middle ring made of resin is fitted and concentrically connected, and the outer circumferential portion of the middle ring protruding from the upper ring and the lower member is slidably fitted into a groove provided on the inner circumferential surface of the outer pot. , a spring plate is welded to the outer peripheral surface of the outer hook, and cuts along the axial direction are formed at multiple locations in the circumferential direction of a cylindrical boss portion protruding from the bottom of the outer hook, and the outer peripheral surface of the boss portion is A rotary hook for a sewing machine, characterized in that a cylindrical tightening member is provided with a taper having a large diameter on the tip side, and a taper corresponding to the taper is provided on the inner circumferential surface, and is fitted into a boss part. . (2) The outer circumferential surfaces of the opposing ends of the upper ring and lower member of the inner pot have deep diagonal grooves on the side away from the opposing ends, and the inner circumferential surface of the middle ring has upper and lower diagonal grooves that are deep on the center side in the vertical direction. A rotary hook for a sewing machine according to claim 1, wherein the upper ring and the lower member are connected by engaging the upper and lower diagonal grooves of the middle ring with these diagonal grooves.