JPH022297Y2 - - Google Patents

Description

[Detailed description of the invention] Technical field of the invention This invention relates to a bobbin case for a sewing machine.

Technical background of the invention and its problems Conventional sewing machine bobbin cases (hereinafter referred to as bobbin cases) store the bobbin wound with bobbin thread inside, and have a thread pull-out port and needle droplet on the outer periphery for pulling out the bobbin thread. A screw hole for screwing the bobbin thread tension adjustment spring, a spring window and an insertion slope for inserting the tail end of the bobbin thread tension adjustment spring are provided, and the tail end of the bobbin thread tension adjustment spring is inserted into the spring window. Then, cover the bobbin thread outlet and engage the claw formed at the tip of the needle droplet window with the adjustment screw. It is configured so that it can be adjusted as appropriate.

In recent years, the materials to be sewn have become more diverse, and in particular, there are many cases of sewing extremely thin materials such as ``diose''. In this case, it is necessary to use extremely low tension, that is, a stable tension of 10 g or less, in order to obtain beautiful seams. However, the bobbin thread tension adjustment spring is made of a thin steel plate approximately 0.25 mm thick, and the tension application range is 0 to approximately 80 g with No. 50 thread, whereas conventional sewing materials have a tension of 30 g to 50 g. Since the bobbin thread tension adjustment spring is used in the system, the adjustment screw presses the bobbin thread tension adjustment spring against the outer circumferential wall of the bobbin case, making the installation stable and stabilizing the bobbin thread tension. In order to loosen the screw, the bobbin thread tension adjustment spring has a tendency to float at the center, and the tail end, which is loosely inserted into the spring window, is used to adjust the bobbin thread as it is wound in the upper and lower order of the bobbin, which occurs when the bobbin thread passes. There was a drawback that the movement caused the position to shift and the bobbin thread tension became unstable, making it impossible to obtain beautiful stitches.

Purpose of the invention This invention was made in view of this point, and the purpose is to provide a bobbin case that can always produce stable and beautiful stitches without causing displacement of the bobbin thread tension adjustment spring even when the bobbin thread tension is 10 g or less. It is something to do.

Summary of the invention This invention is based on a bobbin case in which the tail end of a bobbin thread tension adjustment spring is inserted and screwed into a spring window on the outer periphery of the bobbin case main body. A large number of perpendicular fine grooves are carved, and a protrusion that engages with the fine grooves is provided in the vicinity of the lower thread tension adjustment spring tail end insertion part, so as to suppress the swinging of the screwed lower thread tension adjustment spring. It is.

Embodiment of the invention An embodiment of the invention will be described based on the drawings. Reference numeral 1 denotes a bobbin case. A bobbin wound with a bobbin thread (not shown) is stored in the interior 3 of the bobbin case main body 2, and the bobbin is held in the head 4. A corner portion 6 is formed on which the knob 5 is attached so as to be able to be turned upside down and is loosely fitted into a cauldron (not shown). Further, the outer circumferential portion 7 includes a thread pull-out port 8 for pulling out the bobbin thread, a needle droplet port 9, a screw hole 11 for screwing the bobbin thread tension adjusting spring 10, and a spring into which the tail end 12 of the bobbin thread tension adjusting spring 10 is inserted. A window 13 and an insertion ramp 14 are provided. Micro grooves 15 of this invention are cut into the inclined surface 14. In the spring window, a lower thread tension adjusting spring 10 is provided, in which a protrusion 17 that engages with the minute groove 15 is provided on the curved inner surface 16 near the tail end 12 of the lower thread tension adjusting spring 10, and a bent claw 18 is formed at the tip. The claw 18 is inserted into the needle droplet window 9 and the engagement adjustment screw 19 is screwed in such a manner that it can be tightened and loosened freely.

Effect of the invention With this configuration, loosening the adjustment screw 19 gives a weight of 10g.
Even if the tension is adjusted to a relatively low level, the protrusion 17 of the bobbin thread tension adjustment spring 10 is engaged with the minute groove 15, and positional displacement due to the movement of the bobbin thread that is wound up and down in the bobbin is prevented. Since a stable low tension can be obtained at all times, it has the advantage of being able to sew a wide range of materials, from ultra-thin materials such as ``geo-jets'' to thick materials, and is easy to manufacture.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of this invention. Figure 1 is a perspective view of the bobbin case body and the bobbin thread tension adjustment spring, Figure 2 is a front view of the bobbin case body, and Figure 3 is a perspective view of the bobbin case body and the bobbin thread tension adjustment spring. A perspective view of the bobbin case, and FIG. 4 is a front view of a conventional bobbin case main body.

Claims (1)

[Scope of utility model registration request] In the bobbin case, in which the tail end of the bobbin thread tension adjustment spring is inserted and screwed into the spring window on the outer periphery of the bobbin case body, a large number of minute grooves are formed in the bobbin thread tension adjustment spring insertion slope part of the spring window that runs perpendicular to the direction of the screw hole. 1. A bobbin case for a sewing machine, characterized in that a protrusion is provided on a tail end insertion portion of a bobbin thread tension adjustment spring to engage with the micro groove.