JPS6037111Y2 - Belt transmission mechanism in electric sewing machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a belt transmission mechanism in an electric sewing machine, and more particularly to a belt transmission mechanism equipped with a means for preventing a drive belt with teeth from lifting up from an engagement groove of a drive pulley.

In an electric sewing machine, as an example of which is shown in FIG.
A transmission mechanism is constructed in which a drive belt 7 having teeth is passed between both pulleys 2.4, and the rotation of the motor 1 is transmitted to the main shaft 3 via the drive belt 7. Widely adopted.

However, in this transmission mechanism, the drive pulley 2 is generally made significantly smaller than the driven pulley 4 in order to increase the reduction ratio, so the length of the drive belt 7 wrapped around the drive pulley 2 is limited. It tends to be in short supply.

In particular, as shown in FIG. 1, in order to avoid interference with a transformer 9, etc. disposed between the drive pulley 2 and the driven pulley 4, the drive belt 7 is wound around the intermediate pulley 8 and its running path is When the drive belt 7 is widened, the length of the drive belt 7 wound around the drive pulley 2 becomes smaller, and the number of teeth of the drive belt 7 that mesh with the teeth of the engagement groove 5 of the drive pulley 2 decreases, resulting in - tooth contact. There is a tendency for the load applied to the device to become excessive.

Moreover, the elongation generated on the tension side 7a of the drive belt 7 is transferred to the slack side 7b, and the winding accelerates the reduction in length, so when starting the sewing machine or sewing thick fabric, etc. When the load applied to the drive belt 3 increases in particular, the drive belt 7 lifts up from the engagement groove 5 and the drive belt 7
The teeth 11 of the belt were disengaged from the teeth of the engagement groove 5, and jumping occurred between the drive pulley 2 and the drive belt 7.

Generally, a tension pulley is used to absorb the slack in the belt, but in electric sewing machines, various mechanical parts get in the way and the drive pulley 2 and intermediate pulley 8
The reality is that there is no room to install a tension pulley between the two.

With this background in mind, the present invention has been developed with the aim of solving the above-mentioned problems by preventing the drive belt from winding due to slack in length and lifting up. , the gist of which is,
The drive belt is positioned close to the outer periphery of the drive pulley within the angular range where the drive pulley meshes with the drive belt, at least until the drive belt lifts up from the engagement groove of the drive pulley and disengages from the teeth of the engagement groove. A lifting prevention member is provided which engages with the back surface of the belt to prevent further lifting.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

2 and 3, the motor holder 21 is attached to the machine frame (not shown) by means of two screw members 22 passing through a through hole 23 bored at its right end (in FIG. 2). (as shown).

The through hole 23 of the motor holder 21 has a longitudinal shape that is long in the left-right direction so that its mounting position can be adjusted.

Further, the left half of the motor holder 21 is C-shaped, and a motor 25 is fixed to this C-shaped portion 24 by two screw members 26.

A drive pulley 30 is fixed to an output shaft 31 of the motor 25.

The drive pulley 30 is comprised of a main body member 32 having a head 34 and legs 36, and an annular guide member 37.

In the main body member 32, a plurality of teeth 41 are formed on the outer circumferential surface of the leg portion 36, and a protrusion 38 is made to protrude from the end surface of the leg portion 36.
The output shaft is fixed by a nut 33 non-rotatably interposed between the head 34 and the output shaft 31 and a set screw 35 screwed into the nut 33, which is fitted into the inside and integrated with the guide member 37. It is fixed at 31.

A drive belt 42 is wound between the head 34 of the drive pulley 30 and the guide member 37, and some of the teeth 43 formed on the inner peripheral surface of the drive belt 42 are meshed with the teeth 41. There is.

The motor holder 21 also has a bell crank-shaped roller mounting member 51 at a position diagonally below and to the right of the drive pulley 32 (in FIG. 2), and has two screw members 52 and 53.
installed by.

The through hole 54 of the roller mounting member 51 is circular, but the through hole 55 is elongated in the direction perpendicular to the straight line connecting the through holes 54.55, and the screw member 52.53 is loosened. In this case, it is possible to rotate the screw member 52 by a certain angle.

Further, between the yen coin passage holes 54 and 55 of the roller mounting member 51, a through hole 56 which is slightly larger than the head of the screw member 26 is provided.
is bored in the same direction as the through hole 55.

A shaft member 58 is erected in a direction perpendicular to the plate surface by a plain screw 57 on the arm portion of the roller mounting member 51 that protrudes leftward from the C-shaped portion 24 of the motor holder 21. After the rotating roller 61 is fitted to 59,
It is prevented from being pulled out by an E-shaped hinge 62.

The rotating roller 61 is positioned near the drive pulley 30 (directly below in this embodiment) so that a slight gap exists between its outer circumferential surface and the outer circumferential surface of the drive belt 42 .

It should be noted that it is not essential to position the rotating roller 61 directly below the drive pulley 30 in this way, and the rotating roller 61 is positioned at the end of the engagement end within the engagement angle range of the drive belt 42 of the drive boo IJ 30. It is sufficient if it is located near the area.

Next, the operation of this embodiment will be explained.

A drive pulley 30 fixed to the main shaft 31 of the motor 25 rotates in the direction of arrow B in FIG.

Therefore, the side 42a of the drive belt 42 above the drive pulley 30 in FIG. 2 is the tight side, and the side 42b to the right is the slack side.

During sewing work, if the load applied to the sewing machine main shaft (see Figure 1) of the electric sewing machine increases due to reasons such as thick fabric, and the tension applied to the tension side 42a of the drive belt 42 increases, the tension side 42a A certain amount of elongation occurs.

This extension results in an increase in the amount of slack on the slack side 42b of the drive belt 42, and at the end of the meshing end within the range where the teeth 41 of the drive pulley 30 and the teeth 43 of the drive belt 42 mesh with each other. Drive pulley 30 of drive belt 42
It leads to separation from people.

However, behind the drive pulley 30, a rotating roller 61 is disposed with a small gap between it and the back surface (in this embodiment, the bottom surface) of the drive belt 42.
If it lifts up from the drive pulley 30 even slightly, its back surface is brought into contact with the rotating roller 61.

Since the gap is selected to be smaller than the amount of engagement between the teeth 43 and the teeth 41, the drive belt 4
Even when the back surface of 2 is in contact with the rotating roller 61,
The meshing between the tooth portion 43 and the tooth 41 does not become disengaged at the end of the meshing end.

In other words, the teeth 43 and the teeth 41 are applied to the main shaft of the sewing machine depending on the magnitude of the load, that is, the tension side 42a of the drive belt 42.
Regardless of the amount of tension applied to the teeth, only a certain number of teeth can be meshed with each other within a certain range, and jumping will not occur due to excessive load applied to each tooth. .

In addition, in this embodiment, since the member for preventing the drive belt 42 from lifting is the rotating roller 61, the drive belt 42 will not move even when the back surface of the drive belt 42 engages with the rotating roller 61.
No large load (resistance) is applied to 2.

Furthermore, the rotating roller 61 can adjust the position of the drive pulley 30 in the radial direction.

That is, when adjusting the position, it is sufficient to loosen the screw members 52 and 53 and rotate the roller mounting member 51 around one of the screw members 52.

At this time, the through holes 55 and 56 allow rotation of the button attachment member 51.

Therefore, the size of the gap can be easily adjusted to an optimal value that prevents the drive belt 42 from lifting and does not add unnecessary load to it.

In this way, excellent effects can be obtained by pivotally mounting the rotating roller 61 on the rotatable roller mounting member 51.
As shown by the two-dot chain line in FIG. 2, it is also possible to use a plate member 73 having an arcuate upper surface 71 and a protrusion 72 close to the drive pulley 30 as a lifting prevention member. The advantage is that the purpose can be achieved at low cost.

Furthermore, although the above-described anti-lifting member was positioned so that a slight gap existed between its outer peripheral surface and the outer peripheral surface of the drive belt 42, the lifting prevention member was positioned so as not to impede the movement of the drive belt 42. Of course, when the rotating roller 61 that can rotate smoothly is used as a lifting prevention member, the rotating roller 61 may be constantly engaged with the drive belt 42.

As detailed above, according to the present invention, in the belt transmission mechanism of an electric sewing machine, even when the load applied to the main shaft increases, the drive belt is prevented from lifting out of the engagement groove of the drive pulley, and the number of teeth is Since the teeth of the belt are always reliably engaged with the teeth of the retaining groove, breakage of the teeth, reduction in the life of the drive belt, occurrence of jumping, etc. are well prevented.

Moreover, since the anti-lifting member can be placed outside the drive pulley, where mechanical parts are rarely placed, and is compact, it does not interfere with the placement of other components in the electric sewing machine. There is no.

[Brief explanation of drawings]

FIG. 1 is a front view showing an example of a belt transmission mechanism in a conventional electric sewing machine, FIG. 2 is a front view of main parts showing an example of a belt transmission mechanism according to the present invention, and FIG.
■It is a sectional view. 3: Sewing machine main shaft, 8: Intermediate pulley, 9 Nidransu, 2
1: Motor holder, 25: Motor, 30: Drive pulley,
31: Motor output shaft, 42: Drive belt, 41: Teeth, 4
3: Teeth, 51: Roller mounting member, 61: Rotating roller (
73: Plate member (lifting prevention member).

Claims (4)

[Scope of utility model registration request] (1) A drive having a hook that is passed between a drive pulley provided on the motor and a driven booby provided on the main shaft, and has a series of teeth that mesh with toothed engagement grooves formed on both pulleys. In an electric sewing machine in which the rotation of a motor is transmitted to the main shaft via a belt, the drive belt is located close to the outer periphery of the drive pulley within an angular range in which the drive pulley meshes with the drive belt. A lifting prevention member is provided which engages with the back surface of the drive belt to prevent further lifting until the belt lifts up from the engagement groove and disengages from the teeth of the engagement groove. A belt transmission mechanism in an electric sewing machine. (2) The belt transmission mechanism according to claim 1, wherein the lifting prevention member is a rotating roller that rotates around a center line parallel to the center line of the drive pulley. (3) The transmission mechanism according to claim 2, wherein the rotating roller is adjustable in position substantially in the radial direction of the driving roller. (4) The lifting prevention member faces the back surface of the drive belt near the end of engagement within the angle range where the drive pulley and the drive belt engage. The transmission mechanism according to any one of Items 1 to 3.