JPH0117268Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an upper thread adjustment device for a sewing machine for adjusting the tension of the upper thread of the sewing machine.

Conventionally, there have been devices of this type as shown in FIGS. 1 to 3. Figure 1 is a conceptual diagram showing the concept of the upper thread adjusting device, Figure 2 is a side view of the upper thread adjusting device, and Figure 3 is a side view of the upper thread adjusting device.
The figure is a sectional view showing the - section in FIG. 2. In the figures, the same parts are given the same reference numerals. In the figure, reference numeral 1 denotes a spring stopper bushing, which has an operation guide groove 2 for a thread spring 5 and is attached to a sewing machine frame 4. 3 is a positioning end of the operation start end of the thread spring 5. The thread spring 5 has a contact portion 6 that contacts the positioning end 3 of the spring stopper bush 1 and an upper thread 11.
It has a V-shaped engagement portion 7 that is engaged with, and is loosely fitted onto a tension rod 8 attached to the spring stopper bush 1. A rotary tension disc 9 having an engagement outer periphery 10 around which the upper thread 11 is wound is loosely fitted onto the tension rod 8, and a conical spring 12 and a conical spring 12 that apply pressure to the rotary tension disc 9 are loosely fitted onto the tension rod 8. An adjustment knob 13 for adjusting the pressure is screwed on. A third thread guide 14 guides the upper thread 11 from the bobbin winder (not shown) to the rotary tension plate 9. A thread guide 15 guides the upper thread 11 from the thread spring 5 to the thread guide 16, and is attached to the sewing machine frame 4 together with the third thread hook 14.

Next, the operation of this conventional needle thread adjustment device will be explained with a focus on the thread triangular spring 5. First, the upper thread 11 is wound around the engaging outer periphery 10 of the rotary tension plate 9 about 11/4 times from the third thread hook 14, and then
It is engaged with the V-shaped engagement portion 7 of the thread spring 5.
Next, the upper thread 11 is guided by thread guides 15, 16 and engaged with a thread take-up (not shown). The normal position of the thread triangular spring 5 is such that the abutting portion 6 of the thread triangular spring 5 abuts against the positioning end 3 at the starting end of the spring stop bush 1, as shown by the solid line in FIG. In this state, the path of the needle thread 11 from the engagement outer periphery 10 of the rotary tension plate 9 to the thread guide 15 is V-shaped as shown by the solid line in FIG. When the thread take-up (not shown) starts rising from this state and begins to pay out the upper thread 11, the upper thread 11 assumes a V-shape or a straight line as shown by the two-dot chain line (in FIG. 3). This occurs because the engaging portion 7 of the upper thread 11 of the thread triangular spring 5 moves to 7'. Further, as the thread take-up continues to descend, the upper thread 11 becomes slack, and the thread triangular spring 5 returns to its original position to absorb the slack amount. (The engaging portion is located at the solid line 7 in Figure 3.) However,
When the sewing machine sews at high speed, the inertial force of the thread spring 5 becomes large, and when the thread is fed out, the engaging part operates more than necessary as shown in Fig. 3, resulting in a position as shown by the dotted line 7'' in Fig. 3. However, since the operation timing of the thread spring for the upper thread at the time when the thread take-up lever descends and absorbs the slack of the upper thread 11 is delayed, the slack of the upper thread 11 cannot be sufficiently absorbed and the upper thread becomes double. This caused an abnormality in the thread tension of the needle thread, resulting in loose stitches and uneven thread tension.

This invention was made in order to eliminate the drawbacks of the conventional ones as mentioned above.By adjusting and regulating the operating end of the thread triangular spring, unnecessary operation of the thread triangular spring can be eliminated, and uneven seams and thread tension can be avoided. It is an object of the present invention to provide an upper thread adjustment device for a sewing machine that eliminates unevenness and allows adjustment of the regulating position of the end of operation of a thread triangular spring with a simple configuration.

An embodiment of this invention will be described below with reference to FIGS. 4 to 6. In the figure, reference numeral 17 denotes a spring stopper bush, which has an operation guide groove 18 for the thread triangular spring 5 and a positioning end 19 for the starting end of the thread triangular spring 5. 20 is a screw hole in which the regulating piece 21 is attached. A regulating piece 21 has a positioning end 22 for regulating the operating end of the thread spring 5, is attached along the outer periphery of the spring stopper bush 17, has a bow shape, and is provided with a long groove 23. Note that the positioning end 22 is in contact with the contact portion 6 of the thread triangular spring 5 . This regulating piece 21 is fastened and fixed in a screw hole 20 along the outer periphery of the spring stopper bushing 17 with a screw 24 . In the figure, the same or corresponding parts as in FIGS. 1 to 3 are designated by the same reference numerals.

Next, the operation of the device according to one embodiment of this invention will be explained, focusing on the operation of the thread triangular spring 5.

First, as shown in FIG. 5, the normal position is the same as the conventional one. Next, when the thread take-up (not shown) starts to rise and starts to pay out the upper thread, the upper thread 1
1 changes from a V-shape to a straight line, as shown by the two-dot chain line in FIG. 5, and at this time, the engagement portion 7 of the needle thread 11 of the thread triangular spring 5 is moved to 7'. At this time, unlike the conventional one, the abutment part 6 of the thread spring 5 is attached to the positioning end 2 of the regulating piece 21 attached to the spring stopper bush 17.
2 will be regulated.

In addition, in order to change the stroke S (Figs. 3 and 5) of the thread spring 5 as appropriate depending on the item being sewn by the sewing machine,
Accordingly, the operator may loosen the screw 24, adjust the position of the long groove 23, and change the position of the positioning end 22.

Further, in the above embodiment, an upper thread adjusting device having a rotary tension disc 9 has been described, but the upper thread is held between two known tension discs and the pressure applied to the tension discs is adjusted. Similar effects can be obtained even if the present invention is applied to an upper thread adjustment device that changes the tension applied to the upper thread.

As described above, this invention consists of a spring stopper attached to the sewing machine frame, a tension rod that is provided so as to pass through the axis of the spring stopper, and a tension rod that is loosely fitted into the tension rod and that threads the upper thread. A tension disc for guiding, an adjustment knob attached to the tension rod to adjust the pressure applied to the tension disc, and an adjustment knob that is loosely fitted to the tension rod so as to be rotatable, on which the upper thread from the tension disc is applied. The spring stopper bush is provided with an operation guide groove through which the thread return spring is freely movable, and the thread return spring is fitted on the outer peripheral surface of the spring stop bush in correspondence with the operation guide groove. A regulating piece is provided, and the regulating piece is fixed at a fixed position relative to the outer circumferential surface of the spring locking bushing so as to regulate the movement range of the operating end of the thread triangular spring by adjusting its position relative to the operating guide groove. is configured to be adjustable by a fixing device connected to the spring stopper, thereby eliminating unnecessary movement of the thread tripping spring due to high-speed operation of the sewing machine, eliminating delays in the timing of operation with respect to the upper thread, and increasing the speed of the upper thread. Accurately absorbs slack and eliminates loose seams and uneven thread tension, resulting in beautiful seams. By operating fixing devices such as screws, the fixing position of the regulating piece can be changed to a spring stopper or Since it can be easily adjusted regardless of the tension disc, it is possible to easily change the operating stroke of the thread triangular spring.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram showing the concept of the upper thread adjusting device, Fig. 2 is a side view of the conventional upper thread adjusting device, Fig. 3 is a cross-sectional view showing the - section of Fig. 2, and Fig. 4 is a diagram of the present invention. FIG. 5 is a side view showing one embodiment of the upper thread adjusting device, FIG. 5 is a cross-sectional view taken along the - cross section of FIG. 4, and FIG. 6 is an exploded perspective view of the spring stopper bush. 4 is a sewing machine frame, 5 is a thread spring, 6 is a contact part, 7 is an engaging part, 8 is a tension rod, 9 is a rotary tension plate, 11 is an upper thread, 13 is an adjustment knob, and 17 is a spring stopper. , 18 is an operation guide groove, 21 is a regulating piece, 22 is a positioning end, 23 is a long groove, and 24 is a screw (fixing tool). Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A spring stopper attached to the sewing machine frame, a tension rod provided so as to pass through the axis of the spring stopper, and a tension rod loosely fitted to the tension rod. a tension disc for guiding the upper thread; an adjustment knob attached to the tension rod for adjusting the pressure applied to the tension disc; The spring stopper bush is provided with an operation guide groove through which the thread return spring is movably passed through, and the thread is provided on the outer peripheral surface of the spring stopper bushing in a manner corresponding to the operation guide groove. A regulating piece is provided with which the triangular spring comes into contact, and the regulating piece is arranged on the outer peripheral surface of the spring locking bushing so as to regulate the movement range of the operating end of the thread triangular spring by adjusting its position with respect to the operation guide groove. An upper thread adjustment device for a sewing machine, the needle thread adjustment device for a sewing machine being constructed such that a fixing position thereof can be adjusted by a fixing device coupled to a spring stopper bushing. (2) The needle thread adjustment device for a sewing machine according to claim 1, wherein the fixing device is a screw that fixes the regulating device to the spring stopper bush.