CN1101868C - Flywheel for sewing machine - Google Patents

Abstract

A flywheel or motor pulley used on sewing machines that prevents the thread from the spool from tangling with the flywheel or motor pulley. The manual wheel (57) of the flywheel (58) is exposed outside the cover (62), the hub part (56) is inside the cover, and a slot (1) is formed between the manual wheel and the hub part.

Description

Flywheels for sewing machines

technical field

The present invention relates to a flywheel mounted on the spindle of a sewing machine.

Background technique

Two types of main shaft drive systems are used in industrial sewing machines, indirect drive system and direct drive system; in indirect drive system, the main shaft is rotated by a motor arranged outside The motor in the head turns.

First, referring to Figs. 7 and 8, the indirect drive system will be explained.

The main shaft 54 is rotatably supported on the frame 52 of the machine head 51 through the bearing 53 , the machine head 51 is installed on the workbench 50 , and the main shaft 54 extends along the longitudinal direction of the frame 52 . The main shaft 54 is fixed on the flywheel 58 at the right end in FIG. 8 . The hub portion 56 of the flywheel 58 has a V-shaped belt groove 55 formed on its circumference, and the diameter of the manual wheel 57 is larger than that of the hub 56 . The pulley 60 is fixed on the drive shaft 59 a of the motor 59 installed under the table 50 . V-belt 61 loops around pulley 60 and belt groove 55 on flywheel 58 . Rotation of the motor 59 rotates the flywheel 58 through the V-belt 61 .

Next, the direct drive system is explained with reference to FIGS. 9 and 10 . In this drive system, the motor 59 is mounted in the frame 52 . The motor 59 is fixed on the flywheel 58, and the flywheel 58 has a hub part 56 and a manual wheel 57 as shown in the right end of FIG. 10; the left end of the motor 59 is directly coupled with the main shaft through the motor shaft 63. Rotation of the motor 59 rotates the flywheel 58 and the main shaft 54 .

Both drive systems have a flywheel 58 outside the frame 52 and a belt cover 62 or end 52a extending from the frame to cover the hub portion 56 for the purpose of protecting the operator's hands from injury. There is a gap S between the exposed hand wheel 57 and the cover 62 or frame end 52a.

With this structure, the rotation of the flywheel 58 driven by the motor 59 creates a negative pressure in the narrow space between the flywheel 58 and the cover 62, which causes air to flow from the manual wheel 57 to the space sideways. This air flow draws the thread T pulled from the spool (not shown) through the gap S into the space, because the cylindrical hub portion 56 has a flat surface, so that the thread may be wound around the hub portion 56, V. Shaped belt 61, main shaft 54 or motor shaft 63 are entangled.

Continuing the sewing operation without knowing the occurrence of tangles generates a large amount of waste thread T, and it takes a lot of time to remove the tangled threads, thereby reducing sewing efficiency.

When the tangled wires enter the gap between the end face of the flywheel 58 and the end face of the bearing 53, or the gap between the spindle 54 and the cavity of the bearing 53, it increases the friction between said surfaces, resulting in greater torque, This may cause the main shaft 54 to lock up or burn out the motor 59 .

Japanese Utility Model Application No. Hei 8-76 discloses improvements as described below.

Referring to FIG. 11, an annular portion 60a protruding from one side surface of the motor pulley 60 has a cutout 60b. The cutout 60b is shaped such that its rear edge with respect to the direction of rotation indicated by arrow Y is substantially perpendicular to one end of the annular portion 60a, while the other edge is inclined toward the front of the direction of rotation.

The thread T hooked to the outer surface of the loop portion 60a slides on the sloped edge, reaches and engages the rear edge of the notch 60b ( FIG. 12 ), and wraps around the loop portion 60a as the pulley 60 rotates. This movement prevents the wire from tangling with the motor shaft (not shown).

Figure 13 shows another form. On the side of the pulley 60, a protrusion 60c is provided along the annular portion 60a instead of the above-mentioned notch 60b.

As shown in FIG. 14, the function of the protrusion 60c is the same as that of the notch 60b, and it is also to prevent the wire T from being entangled with the motor shaft.

Nevertheless, the improvement of Japanese application No. Hei 8-76 still causes the suspension wire T to get tangled with the hub portion 56 or the V-shaped belt 61, although it prevents the wire from getting tangled with the main shaft. This creates a problem that continuing sewing without knowing the tangle produces a large amount of waste thread T, and it takes a lot of time to remove the tangle, thereby reducing sewing efficiency.

Summary of the invention

Accordingly, it is an object of the present invention to provide a flywheel for a sewing machine which prevents thread tangling.

In order to solve the above-mentioned problems, the present invention provides a flywheel for use in a sewing machine, which is fixed to a rotating shaft and has a hub portion covered by a cover and an exposed manual wheel, wherein, between the manual wheel and the At least one groove is formed on the circumference between the hub portions, the groove having a smooth surface.

Preferably, the groove is formed on a circular line.

In a particular configuration, said grooves form a helical shape.

In another more preferred configuration, a groove is formed on the circumference of the flywheel opposite the gap between the end of the cover and the hand wheel.

According to the present invention, even when the wire hangs down on the hub portion, enters the groove and slides on the surface of the groove, and the wire is pulled toward the hub side by the air flow generated by the rotation of the flywheel, the wire can be prevented by the side edge surface of the groove. Move towards the hub side, therefore, it is possible to prevent the thread from tangling around the hub portion. As a result, the present invention saves wastage of waste thread, and time for removing tangled threads, thereby increasing the efficiency of sewing operations.

Description of drawings

The accompanying drawings are briefly described below.

Fig. 1 is the perspective view of the first embodiment of the present invention;

Fig. 2 is a sectional view when the flywheel of the first embodiment of the present invention is applied to an indirect drive system;

Fig. 3 is a side view when the flywheel of the first embodiment of the present invention is applied to an indirect drive system;

Fig. 4 is a sectional view when the flywheel of the first embodiment of the present invention is applied to a direct drive system;

Fig. 5 is a sectional view when the flywheel of the second embodiment of the present invention is applied to an indirect drive system;

Fig. 6 is a sectional view when a flywheel according to a third embodiment of the present invention is applied to a direct drive system;

Figure 7 is a front view of a conventional sewing machine driven by an indirect drive system;

Fig. 8 is a sectional view of a conventional sewing machine in an indirect drive system;

Figure 9 is a front view of a conventional sewing machine driven by a direct drive system;

Figure 10 is a cross-sectional view of a conventional flywheel component in a direct drive system;

Fig. 11 is a perspective view of an example of a conventional motor pulley;

Figure 12 is a left side view of the motor pulley shown in Figure 11;

13 is a perspective view of another example of a conventional motor pulley;

Fig. 14 is a left side view of the motor pulley of Fig. 13 .

Detailed description of the preferred embodiment

Embodiments of the present invention will be described below with reference to FIGS. 1-6. The same elements as in the description of the prior art bear the same names and reference numerals.

Figures 1-3 illustrate one embodiment of an indirect drive system. An annular groove 1 is formed on the circumference of the flywheel 58 opposite to the gap S, that is to say, between the hand wheel 57 and the belt cover 62 . The surface of groove 1 has low friction. And the groove 1 should be of sufficient depth so that the thread T does not get tangled, as a groove 1 that is too deep may tangle the thread.

When a thread end from a spool (not shown) enters the gap S, it is suspended from the thread slot 1 on the hub portion 56, as shown in FIG. In this state, clockwise rotation of the flywheel 58 will not engage the wire around the flywheel because the slot 1 has a smooth surface to slide on.

In addition, even if the wire T is pulled toward the frame 52 side (left side in FIG. 2 ) by the air flow generated between the cover member 62 and the hub portion 56, the wire T is not affected by the left surface of the groove 1. out of slot 1 so as not to become entangled with hub portion 56 .

Figure 4 shows an embodiment in a direct drive system.

Using the same structure as in the indirect drive system, a slot 1 is formed on the circumference of the flywheel 58 opposite the gap S, that is, between the hand wheel 57 and the frame end 52a. When the thread T starts from the spool (not shown) and enters the gap S, the thread suspended on the hub portion 56 falls into the groove 1 as shown in FIG. 3 .

As in an indirect drive system, a wire end falling into slot 1 will not wrap around the flywheel because slot 1 has a sliding surface.

In addition, even when the wire T is pulled to the left by the air flow generated between the frame end 52a and the hub portion 56 (as shown in FIG. Move out of slot 1 so as not to get tangled up with hub portion 56 .

In the above structure, the groove 1 may be a plurality of grooves as shown in FIG. 5 .

As another form, the groove 1 may be a spiral groove 1a as shown in FIG. 6, and its cross section is arc-shaped.

The helical groove 1a forms such a structure that when the flywheel 58 rotates, the action line T moves toward the manual wheel due to its helical action. Therefore, when the flywheel 58 rotates, the wire T falling into the groove 1a slides on the surface of the groove because the groove 1a has low friction, and moves gradually toward the manual wheel 57 along the groove 1a.

In addition, even if the wire T is drawn by the air flow generated between the frame end 52a or the belt cover 62 and the hub portion 56, the wire T will not move leftward in FIG. Therefore, it will not get tangled with the hub portion 56.

The invention is also applicable to motor pulleys fixed to machine drive motors in indirect drive systems.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the present invention.

As described above, according to the present invention, even when the wire hangs downward on the hub portion, falls into the groove and slides on the surface of the groove, and tends to be pulled toward the hub by the air flow generated by the rotation of the flywheel, the wire Under the action of the side surface of the groove, it will not move toward the hub side, thereby preventing it from being wrapped around the hub or tangled with the V-shaped belt. As a result, the present invention saves the consumption of waste threads and thus brings economic benefits, saves the time for removing tangled threads, and further improves sewing efficiency.

In addition, since the wire is not tangled with the hub portion, the wire is prevented from being tangled with the main shaft, or the motor shaft, thereby preventing the motor from being locked or burned due to increased torque due to the tangled wire.

Claims (4)

1. A flywheel for a sewing machine, comprising a hub portion covered by a cover and an exposed manual wheel, at least one groove is formed on the circumference of the hub portion, characterized in that the groove has a function for preventing thread A forward side edge surface and a smooth, flat bottom surface parallel to the direction of extension of the hub portion. 2. A flywheel according to claim 1, wherein said groove forms a circular ring. 3. The flywheel of claim 1, wherein the grooves are formed in a helical form. 4. The flywheel of claim 1, wherein the groove is on the circumference of the flywheel opposite the gap between the cover and the handwheel.

Images