JPH03212287A - Bobbin cylinder for sewing machine - Google Patents

Abstract

PURPOSE:To prevent a bobbin from racing when the sewing operation is stopped by forming a stepped seat on the bottom of an inner bobbin cylinder, near to the periphery of the inner bobbin cylinder so that the stepped part faces the opening end of the inner bobbin cylinder. CONSTITUTION:A protrusion 14 having a stepped seat at a position which is radially outward from the center line l1, that is, adjacent to a cylindrical part 11, is integrally incorporated with the bottom 12 of an inner bobbin cylinder 4 with the use of a die molding process. The protrusion 14 is projected toward the opening end of the cylinder from the inner surface 12 of the bottom 12, and one of flanges 15 of a bobbin 7 stored in the inner bobbin cylinder 4, which is near to the bottom 12, makes contact with the end face 14a of the protrusion 14 on the opening end side. Accordingly, the bobbin 7 is rotated around an axis 11 as a bobbin thread is consumed during sewing operation, and when the sewing operation is stopped, a braking force effected by the slide friction between the flange and the protrusion 14 is applied to the bobbin 7, thereby it is possible to prevent the bobbin 7 from racing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sewing machine hook, and more particularly to a structure for preventing a bobbin housed in an inner hook from idling when the sewing operation is stopped.

2. Description of the Related Art Traditionally, a full-rotation hook has been placed below the bed of a lockstitch sewing machine, etc., and this full-rotation hook has an outer hook that is driven to rotate around a horizontal axis of rotation, and an outer hook inside the outer hook. It basically consists of an inner bag to be stored, a bobbin case that is detachably attached to the inner bag, and a bobbin that is stored in the bobbin case. One flange of the bobbin stored in the bobbin case is in contact with the bottom of the inner hook, and as the bobbin thread wound around the bobbin is taken out during the sewing operation, the bobbin rotates. The lower thread is drawn out while rotating around the axis.

In such prior art, when the sewing operation is stopped,
The bobbin continues to rotate due to inertia, which causes the bobbin thread to become loose within the bobbin case. Therefore, in a sewing machine such as an industrial sewing machine that is configured to rotate an outer hook at high speed, the sewing speed is high, so the bobbin thread is consumed at a high rate, and the bobbin inside the inner hook rotates at a high speed. , as the bobbin thread is consumed from radially outward to radially inward,
The rotation speed of the bobbin increases further. Therefore, it is difficult to stop the rotation of the bobbin almost at the same time as the sewing operation is stopped, and if the bobbin thread is unnecessarily fed out in the bobbin case due to the idle rotation due to the inertia of the bobbin, it may cause tangles or the thread may become loose. This may cause balls to form.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a hook for a sewing machine that can prevent the bobbin from idling when the sewing operation is stopped.

Means for Solving the Problems The present invention provides a sewing machine kettle, characterized in that a protrusion is formed on the bottom of the inner hook, protruding toward the open end of the inner hook, closer to the periphery of the inner hook. .

Function According to the present invention, the protrusion that protrudes toward the open end side is formed on the bottom of the inner hook near the first part of the periphery of the inner hook, so that the flange of the bobbin stored in the inner hook is attached to the protrusion. A braking force is applied to the bobbin rotated during sewing by the friction between one flange of the bobbin that comes into contact with the riser and the protrusion, thereby preventing the bobbin from spinning idly when the sewing operation is stopped. can.

Embodiment FIG. 1 is a simplified sectional view showing the basic configuration of an embodiment of the present invention. For example, a vertical full-rotation hook 1 provided on a lockstitch sewing machine includes an outer hook 3 fixed to a lower shaft 2 that is driven to rotate around a horizontal rotation axis, and an inner hook 4 housed inside the outer hook 3. , a bobbin case 5 that is detachably attached to the inner hook 4, and a bobbin thread 6 that is stored in the bobbin case 5.
It has a bobbin 7 around which it is wound. A track groove 8 is formed in the circumferential direction on the inner circumferential surface of the outer hook 3, and a rail 9 formed on the outer circumferential surface of the inner hook 4 is fitted into the rail groove 8 to prevent rotation of the inner hook. In this state, the outer hook 3 is driven to rotate around the rotation axis of the lower shaft 2.

The inner hook 4 includes a cylindrical portion 11 that is a generally right cylindrical peripheral portion on which a rail 9 is formed, and a cylindrical portion 11 that is formed in the axial direction of the cylindrical portion 11.
It has a bottom part 12 that is vertically connected to the universal end part, and a stud 13 is erected on the bottom part 12 toward the open end side of the inner pot 4. The bottom 12 of such an inner hook 4 has a central axis 11.
A protrusion 14 is integrally formed radially outward, that is, close to the cylindrical portion 11, by molding or the like. The protrusion 14 is formed to protrude from the inner surface 12a of the bottom portion 12 toward the open end side, and a bobbin 7 housed in the inner hook 4 is formed between the protrusion 14 and the end surface 14a on the open end side.
One flange 15 disposed on the bottom 12 side of the flange abuts.

With this configuration, during the sewing operation, the bobbin 7 is rotated around the axis p1 as the bobbin thread is consumed, and when the sewing operation is stopped, the bobbin 7 is rotated due to the sliding friction between the flange and the protrusion 14. A braking force acts on the bobbin 7, thereby preventing the bobbin 7 from spinning idly.

The aforementioned protrusion 14 is attached to the bottom portion 12 as shown in FIG.
However, in another embodiment of the present invention, the protrusion 14b that is continuous with the cylindrical portion 11 and protrudes radially inward is formed on both sides in the circumferential direction as shown by the imaginary line. It may be provided over the entire range.

Further, as another embodiment of the present invention, the protrusions 14, 14a may be formed intermittently at intervals in the circumferential direction.

Effects of the Invention According to the present invention, since a protrusion is formed at the bottom of the inner case closer to the peripheral edge, one flange of the bobbin stored in the inner case slides on the protrusion. This prevents the bobbin from rotating idly when the sewing operation is stopped. Therefore, there is no fear that the bobbin thread will be unnecessarily let out, thereby preventing the thread from becoming loose or tangled.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a simplified basic configuration of an embodiment of the present invention, and FIG. 2 is a front view of the inner pot 4. As shown in FIG. l...Vertical full rotation is J, 4...Inner pot, 7...Bobbin, 12...Bottom, 14...Protrusion

Claims (1)

[Claims] A sewing machine hook characterized in that a protrusion protruding toward the open end of the inner hook is formed on the bottom of the inner hook closer to the periphery of the inner hook.