JPH0510793Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a power transmission device that transmits the rotational motion of a main shaft to a driven shaft perpendicular to the main shaft to rotate the driven shaft back and forth, and is particularly applicable to edge overcasting. The present invention relates to a power transmission device suitable for use as a looper drive mechanism in a sewing machine.

[Prior Art] Generally, in an overlock sewing machine, the rotational motion of the main shaft is transmitted to the looper shaft perpendicular to the main shaft via a power transmission device, and the looper shaft is rotated back and forth to swing the looper. things are being done.

FIG. 19 shows a conventional power transmission device of this type. In the figure, reference numeral 1 is a main shaft, and an eccentric cam 2 having a spherical circumferential surface is fixed to the main shaft 1. The eccentric cam 2 is rotatably arranged in a spherical receiving part 5 formed between the rod 3 and the upper end cap 4.

On the other hand, the looper shaft 6 perpendicular to the main shaft 1 has
As shown in FIG. 19, a swinging rod 7 that is perpendicular to the looper shaft 6 is fixed, and a ball journal 8 is attached to a position near the tip of the swinging rod 7. is rotatably supported by a spherical bearing 10 formed between the rod 3 and the lower end cap 9.

In the above configuration, when the main shaft 1 rotates, the eccentric cam 2 rotates eccentrically, thereby causing the rod 3 to reciprocate up and down. When the rod 3 reciprocates up and down, the swinging rod 7 swings up and down, and the looper shaft 6 reciprocates.

[Problems to be solved by the invention] In the conventional power transmission device having the above configuration, the rotational motion of the main shaft 1 is directly transmitted to the looper shaft 6 perpendicular to the main shaft 1 without using a gear mechanism etc. Since the shaft 6 can be rotated back and forth, it has the advantage that the structure is simple and the device can be made smaller.

However, since the sliding part between the eccentric cam 2 and the receiving part 5 and the sliding part between the spherical journal 8 and the spherical bearing part 10 have a ball bearing structure, it is difficult to process convex and concave spherical surfaces. It is not easy and requires familiarization. Furthermore, since the receiving part 5 and the spherical bearing part 10 are divided into the rod 3 and the respective caps 4 and 9, it is necessary to separate them once and then reassemble them by accurately positioning them.

As described above, the conventional power transmission device requires a great deal of time and effort to manufacture and assemble, and there is a problem in that it is difficult to apply it to a relatively inexpensive general household sewing machine.

This idea was created in view of the current situation,
To provide a power transmission device that has a simple structure, can be miniaturized, and is easy to manufacture and assemble.

Another object of the present invention is to provide a power transmission device that can easily adjust the reciprocating rotation angle of the driven shaft.

[Means for Solving the Problem] The present invention provides the following as a means for achieving the above-mentioned main purpose:
In a power transmission device that transmits rotational motion of a main shaft to a driven shaft perpendicular to the main shaft to cause the driven shaft to reciprocate, one end is connected to the main shaft via an eccentric rotation mechanism, and a rod is connected to the main shaft to reciprocate by rotation. a first piece member rotatably mounted around an axis parallel to the main shaft in a hole provided at the other end of the rod; an opening provided at the center of the first piece member; a swinging rod that protrudes radially from the driven shaft and whose tip is inserted into the opening; a swinging rod that is arranged in the opening so as to be rotatable around an axis parallel to the driven shaft; A second bridge member having a guide hole that is slidably penetrated in the axial direction.

In addition, the present invention provides, as a means for achieving the other object, that the eccentric rotation mechanism is constituted by an eccentric cam that is fixed to the main shaft and rotatably fitted into a hole provided at one end of the rod. Features.

[Operation] In the power transmission device according to the present invention, when the main shaft rotates, its rotational force is transmitted to the rod via the eccentric rotation mechanism, and the rod reciprocates. On this occasion,
The rod will move up and down while rocking,
Since the first piece member is rotatably mounted in the hole of the rod, it can move up and down while maintaining the same posture. When the first bridge member moves up and down, this movement is transmitted to the rocking rod via the second bridge member, the rocking rod swings, and the driven shaft rotates back and forth. At this time, the second bridge member is structured to be able to rotate around an axis parallel to the driven shaft, and the tip of the swinging rod is slidably passed through the guide hole of the second bridge member in the axial direction. Therefore, the swinging rod swings while sliding in the guide hole, and the second piece member rotates back and forth around an axis parallel to the driven shaft in accordance with the swinging of the swinging rod. Become. This absorbs unreasonable force, eliminates the need for a ball bearing structure for the interlocking part between the main shaft and the rod, and the interlocking part between the rod and the swinging rod, resulting in a flat bearing structure that is inexpensive and easy to assemble. becomes possible.

In this case, if the eccentric rotation mechanism is configured with an eccentric cam that is fixed to the main shaft and rotatably fitted into a hole provided at one end of the rod, a crank part is provided on the main shaft to form an eccentric rotation mechanism. Unlike,
The position at which the eccentric rotation mechanism is fixed to the main shaft can be easily changed, thereby making it possible to adjust the reciprocating rotation angle of the driven shaft.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

1 and 2 show an example of a power transmission device according to the present invention. In the figures, reference numeral 11 is a main shaft rotationally driven by a motor (not shown) of an overlock sewing machine. One end of a rod 13 is connected to the rod 11 via an eccentric cam 12.

As shown in FIGS. 3 and 4, the eccentric cam 12 includes a flat disk cam portion 12a having a predetermined eccentricity, and is integrally provided at one axial end of the flat disk cam portion 12a. After the eccentric cam 12 is attached to the main shaft 11 as shown in FIG.
The shaft is fixed to the main shaft 11 by tightening a set screw 14 threaded into the shaft. In this embodiment, the eccentric cam 12 constitutes an eccentric rotation mechanism that converts the rotational movement of the main shaft 11 into the reciprocating movement of the rod 13, which will be described later.

On the other hand, as shown in FIGS. 1, 2 and 5, the rod 13 is connected to the flat disk cam portion 1
An annular cam hole 1 into which 2a is rotatably fitted
3a, an annular hole 13b into which a first piece member 15 (described later) is attached, and both holes 13a, 13.
As shown in FIG. Set screw 1 on the left end surface in the figure.
By attaching the disk-shaped cover plate 17 through the shaft stopper 12b and the cover plate 17, the shaft stopper 12b and the cover plate 17 are supported from both sides in the axial direction to prevent the eccentric cam 12 from coming off.

The first piece member 15 attached to the hole 13b
As shown in Figures 2, 6 and 7,
A shaft portion 15a that is fitted into the hole portion 13b so as to be rotatable about an axis parallel to the main shaft 11;
a, and a flange portion 15b provided at one end in the axial direction of the flange portion 15b, and an elongated opening 19 having a long axis in the swinging direction of the swinging rod 18, which will be described later, is provided at the axial center of the flange portion 15b. In addition, the shaft portion 15a includes:
As shown in FIGS. 6 and 7, the opening 1
A fulcrum pin insertion hole 20 is bored in the direction of the short axis of 9. As shown in FIG. 2, this first piece member 15 is assembled into a disc-shaped piece by fitting the shaft portion 15a into the hole 13b of the rod 13, and then attaching a set screw 21 to the left end surface of the shaft portion 15a in the figure. By attaching the lid 22, it is prevented from coming off from the hole 13b. In the center of the lid body 22, as shown in FIG. 2, there is an opening 2 having the same shape as the opening 19.
3 is provided.

As shown in FIGS. 1 and 2, the swinging rod 18 projects perpendicularly in the radial direction from a looper shaft 24 that is perpendicular to the main shaft 11, and its tip end is located inside the opening 19. The second bridge member 25 is inserted into the opening 19 and is slidably supported by the second bridge member 25 installed in the opening 19 .

That is, at the base end of the swinging rod 18, there is a second
As shown in FIG. 8 and FIG. 8, a male threaded portion 18a is provided which is inserted into a hole 24a provided in the looper shaft 24 and fixed by a washer 26 and a nut 27. , 8th
As shown in FIG. 9 and FIG. 9, a slide shaft portion 18b is provided which is formed into a semi-cylindrical shape by cutting a part of the circumferential surface, and this slide shaft portion 18b is slidable on a second piece member 25, which will be described later. It is gaining support. And as a result, Fig. 2, 10
11 and 12, the swinging rod 18 swings as the rod 13 reciprocates, and the looper shaft 24 swings back and forth at a predetermined rotation angle. .

The second piece member 25 is shown in FIGS. 13 to 16.
As shown in the figure, it has a rectangular prism shape with short dimensions.
A guide hole 28 is provided at the axial center of the second piece member 25, and a guide hole 28 is provided through which the slide shaft portion 18b is slidable in the axial direction.
As shown in FIGS. 12 and 14, fulcrum holes 30 are provided, into which the fulcrum pins 29 inserted and fixed in the fulcrum pin insertion holes 20 are fitted and locked. The second bridge member 25 is rotatable around the axis of the fulcrum pin 29. This second piece member 2
5, a pin insertion hole 31 is provided in the upper surface of the pin insertion hole 31, as shown in FIGS. and the second piece member 25
A rotation stopper pin 32 is inserted and fixed to prevent rotation around the slide shaft portion 18b. As a result, the axis of the fulcrum pin 29 is aligned with the looper shaft 24.
and the second piece member 25 is always parallel to the looper shaft 2.
It is designed to rotate around an axis parallel to 4.
Note that the rotation stopper pin 32 can be omitted by forming the guide hole 28 in the same semicircular shape as the slide shaft portion 18b.

Next, the operation of this embodiment will be explained.

When the main shaft 11 rotates, the eccentric cam 12 fixed to the main shaft 11 rotates eccentrically, and the rod 13 reciprocates up and down in FIGS. 1 and 2 accordingly. At this time, the rod 13 is connected to the eccentric cam 12.
Since it is driven up and down, it moves up and down while swinging from side to side, as shown in FIG.

However, the first piece member 15 installed in the hole 13b at the lower end of the rod 13 is rotatable with respect to the hole 13b and is prevented from rotating by the rotation stopper pin 32, so that the same Move up and down while maintaining your posture.

When the first piece member 15 moves up and down, the second piece member 2 installed in the opening 19 of the first piece member 15
5 also moves up and down, and this movement is transmitted to the swinging rod 18, which causes the swinging rod 18 to move up and down.
It swings up and down as shown in the figure. As a result, the looper shaft 24 reciprocates at a predetermined rotation angle.

By the way, if the second piece member 25 is fixed to the swinging rod 18 like the conventional ball journal 8, the swinging of the swinging rod 18 will draw an arcuate trajectory. In order to easily transmit the movement of the rod 13 to the swinging rod 18, the rod 13 must have a structure that allows it to swing left and right, as shown in FIG. 2, for example. Must have a bearing structure.

However, in this embodiment, the slide shaft portion 18b of the swinging rod 18 is inserted into the guide hole 28 of the second bridge member 25.
Since it passes through the rod 18b slidably in the axial direction, the force that attempts to swing the rod 13 from side to side in FIG. 2 can be absorbed by the slide of the slide shaft portion 18b. In addition, the second bridge member 25 follows the swinging of the swinging rod 18 and rotates around an axis parallel to the looper shaft 24, so no matter what swinging position the swinging rod 18 is in, it will not slide. The shaft portion 18b can be slid smoothly. For this reason, rod 13
The upper and lower ends of the bearing can have a flat bearing structure, making the bearing part easy to manufacture and eliminating the need for break-in operation.

Further, since it has a flat bearing structure, there is no need to divide the holes 13a and 13b at both ends of the rod 13, and the rod 13 can be manufactured easily.

In addition, an eccentric cam 1 is used as an eccentric rotation mechanism that converts the rotational motion of the main shaft 11 into a reciprocating motion of the rod 13.
2, the axial attachment position to the main shaft 11 can be easily changed by loosening the set screw 14. Thereby, the rotation angle of the looper shaft 24 can be freely adjusted within a certain range. That is, by moving the eccentric cam 12 to the left in FIG. 2 and bringing the rod 13 closer to the looper shaft 24, the rotation angle of the looper shaft 24 can be increased. By moving the rod 13 to the right in FIG. 2 and separating it from the looper shaft 24, the rotation angle of the looper shaft 24 can be reduced.

17 and 18 show another embodiment of the present invention, in which a second bridge member 35 is used in place of the second bridge member 25 in the previous embodiment.

That is, as shown in FIGS. 17 and 18, the second bridge member 35 is formed in the shape of a round bar having a ring groove 35a on the outer circumferential surface of one end in the axial direction, and both ends thereof Fulcrum pin insertion hole 20
It is rotatably inserted into the The fulcrum pin is prevented from coming off from the insertion hole 20 by the retaining screw 36 that engages with the ring groove 35a. Further, a guide hole 37 is provided in the axial center of the second piece member 35, as shown in FIGS. 17 and 18, and the guide hole 37 is perpendicular to the axis of the second piece member 35. The swing rod 1
The slide shaft portion 18b of No. 8 extends through the slide shaft portion 18b so as to be slidable in the axial direction. Similarly to the second bridge member 25 in the embodiment described above, the second bridge member 35 is secured by a rotation stopper pin 39 inserted and fixed into the pin insertion hole 38.
Rotation around the slide shaft portion 18b is prevented.

Note that the pin insertion hole 38 is inserted into the axial center of the second piece member 35 from the right end in FIG. 17 to the guide hole 3.
7, and a rotation preventing pin 39 may be inserted and fixed into this pin insertion hole 38 to prevent rotation. In this case, it goes without saying that the flat surface of the slide shaft portion 18b needs to be directed to the right in alignment with the position of the rotation stopper pin 39, rather than being directed upward as shown in FIG.

In other respects, the configuration is the same as in the previous embodiment.

By using the second bridge member 35 in place of the second bridge member 25 in the embodiment described above, the structure can be further simplified and the same effects as in the embodiment described above can be obtained.

In both of the above embodiments, the eccentric cam 12 fixed to the main shaft 11 is used as an eccentric rotation mechanism that converts the rotational motion of the main shaft 11 into reciprocating motion and transmits it to the rod 13. It is also possible to provide an eccentric rotation mechanism by providing a crank portion. Further, the cam hole 13a or the hole 13b of the rod 13 may have a divided structure as required.

Furthermore, in both of the embodiments, the first piece member 1
5 is rotatably fitted into the hole 13b of the rod 13. However, the amount of relative displacement required between the first bridge member 15 and the hole 13b depends on the eccentricity of the eccentric cam 12. Rod 13 due to rotation
This amount is sufficient to absorb the horizontal vibration of the
Therefore, the first piece member 15 does not need to be rotatable, but only needs to have a structure that allows it to rotate within a certain range.

[Effects of the invention] As explained above, the present invention has a structure that directly transmits the rotational motion of the main shaft to the driven shaft perpendicular to the main shaft without using a gear mechanism or the like, and allows the driven shaft to rotate back and forth. This simplifies the structure and allows the device to be made smaller.

In addition, the present invention has a structure in which when the swinging rod swings, its tip can slide in the guide hole of the second piece member in the axial direction, and the second piece member is parallel to the driven shaft. Since the direction of the guide hole can be changed freely following the swinging of the swinging rod, the swinging rod can be slid smoothly within the guide hole. For this reason,
The bearings at both ends of the rod can have a flat bearing structure instead of a ball bearing structure, resulting in an inexpensive power transmission device that is easy to manufacture and assemble.

In this case, by configuring the eccentric rotation mechanism with an eccentric cam that is fixed to the main shaft and rotatably fitted into a hole provided at one end of the rod, it is possible to easily position the eccentric rotation mechanism on the main shaft. This allows the reciprocating rotation angle of the driven shaft to be freely changed within a certain range without requiring replacement of parts.

[Brief explanation of the drawing]

Fig. 1 is an external view of a power transmission device showing an embodiment of the present invention, Fig. 2 is a sectional view of Fig. 1, Fig. 3 is a configuration diagram of the eccentric cam shown in Fig. 2, and Fig. 4 is a diagram showing the structure of the eccentric cam shown in Fig. 3 is a left side view, FIG. 5 is a configuration diagram of the rod seen from the side of FIG. 1, FIG. 6 is a configuration diagram of the first piece member shown in FIG. The left side view, Figure 8 is a detailed view of the swinging rod, Figure 9 is the right side view of Figure 8, and Figure 10 is a detailed view of the swinging rod.
11 is a view corresponding to FIG. 2 showing the reciprocating movement of the rod and the swinging of the swinging rod as the main shaft rotates, and FIG. 12 is a sectional view taken along the line -- in FIG.
Fig. 13 is an enlarged view of the second piece member shown in Fig. 2, Fig. 14 is an enlarged view of the second piece member shown in Fig. 12, Fig. 15 is a side view of Fig. 13, and Fig. 16 is an enlarged view of the second piece member shown in Fig. 12. 14 is a side view, FIG. 17 is an enlarged cross-sectional view of main parts showing another embodiment of the present invention, and FIG. 18 is a side view of FIG. 17.
The line sectional view, FIG. 19, is a diagram corresponding to FIG. 2 showing a conventional power transmission device. 11... Main shaft, 12... Eccentric cam, 13... Rod, 13a... Cam hole, 13b... Hole, 1
3c... Rod part, 15... First piece member, 18...
... Swinging rod, 18b... Slide shaft portion, 19... Opening, 20... Fulcrum pin insertion hole, 24... Looper shaft, 25, 35... Second piece member, 28, 37...
Guide hole, 29... fulcrum pin, 30... fulcrum hole,
31, 38... Pin insertion hole, 32, 39... Rotating pin, 35a... Ring groove, 36... Retaining screw.

Claims (1)

[Claims for Utility Model Registration] 1) A power transmission device that transmits rotational motion of a main shaft to a driven shaft perpendicular to the main shaft to rotate the driven shaft back and forth, one end of which is connected to the main shaft via an eccentric rotation mechanism. a first rod which is rotatably mounted in a hole provided at the other end of the rod and is rotatable around an axis parallel to the main shaft;
a bridge member; an opening provided in the center of the first bridge member; protruding in the radial direction from the driven shaft;
a swinging rod whose tip is inserted into the opening; the swinging rod is arranged in the opening so as to be rotatable about an axis parallel to the driven shaft, and the tip of the swinging rod is slidably inserted in the axial direction; The second one has a guide hole.
A power transmission device comprising: a bridge member; 2) Claim 1, wherein the eccentric rotation mechanism is comprised of an eccentric cam that is fixed to the main shaft and rotatably fitted into a hole provided at one end of the rod.
The power transmission device described.