JPS5894889A - Rotation detector for sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotation detector for a sewing machine, and particularly to a rotation detector for a sewing machine that is coupled to the upper shaft of the sewing machine.

In a sewing machine such as an industrial sewing machine that is configured to automatically perform various sewing controls, there are various functions such as detection of the rotational speed of the upper shaft of the sewing machine, detection of the upper position of the needle, detection of the lower position of the needle, and timing position of the needle thread trimming. It is necessary to perform various rotation detections related to the rotation of the sewing machine shaft, such as detection. A conventional rotation detector for a sewing machine for detecting this rotation consists of a magnetized ring magnet and a Hall element. It was the composition.

However, the conventional detector with the above configuration requires a particularly thick and fairly large ring magnet in order to obtain a reliable detection operation, and the detector itself tends to be large.
Furthermore, since the rotational moment of the ring magnet is large, there is a drawback that the rotating part or the magnet is easily damaged, especially in recent high-speed sewing machines. Furthermore, with conventional detectors, it is very troublesome to adjust and change the detection position of the detector depending on the root stock or usage mode.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to provide a rotation detector for sewing machines that is small, lightweight, can obtain highly accurate detection operation, and can easily adjust the detection position. To achieve the above objectives: 1.
This invention relates to a pace fixed to a sewing machine body, a coupling shaft rotatably held by the pace, one end of which is coaxially connected to a sewing machine shaft, and which rotates integrally with the sewing machine shaft; an optical mark disk coaxially attached to the shaft; a light emitter disposed on the space opposite the optical mark disk for detecting optical marks formed concentrically on the optical mark disk; The present invention is characterized in that a rotation detector is constituted by the light receiver.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 is a sectional view of a rotation detector for a sewing machine according to the present invention. This detector is fixed to a frame (not shown) of the sewing machine body via a mounting part 12m, and is rotatably held by the pace 12 via a bearing 14, 16, and a coupling hole at one end. The sewing machine has a coupling shaft 10 which is connected to the shaft end of a sewing machine upper shaft (not shown) through a thread 10JI and rotates together with the sewing machine upper shaft.

A collar 18.20 that is divided into two parts in the axial direction of the coupling shaft 10 and is slip rotatable is inserted into the tip end 10b of the coupling shaft 10, and this collar 18.20 is tightened to the coupling shaft 10 by a fixing screw 22. Fixed.

The collar 18 has two optical mark disks 24.2.
8 are installed coaxially in a stacked manner. The optical mark discs 24, 28 are pressed against the seventh rank portion of the collar 18 by a compression spring 30, one end of which is locked by the collar 20. One optical mark disk 24 has a collar 18
The other optical mark disc 28 is tightly fitted to the collar 18 so as to be able to slip and rotate against the collar 18, while the other optical mark disc 28 is non-rotatably positioned on the collar 18 as will be described later. Therefore, by loosening the fixing screw 22 and changing the mounting angular position of the collar 18 with respect to the coupling shaft 10, it is possible to simultaneously adjust the mounting angular position of both optical mark discs 24, 28 with respect to the coupling shaft 10. The optical mark disk 24 can be used to adjust its mounting angle position by itself. Note that the collar 20 locks one end of the suppression spring 30 and also locks the bearing 14 of the coupling shaft 10.
16 is prevented from falling out.

FIGS. 2 and 3 show the optical mark disks 24 and 2.
8 shows the optical mark surface. The plate surfaces of the inner disks 24 and 28 are not light-reflecting surfaces, and the non-reflecting surfaces are coated with light-reflecting optical markings 24 a, 24 b, for example by printing.
28 m and 28 b are formed in concentric circles.

As shown in the figure, two systems of optical marks 24M and 24b, and 28a and 28b are formed concentrically so as not to overlap each other. Optical mark 24Jl on disk 24
is for detecting the lower position of the needle, and the optical mark 24b is for detecting thread trimming timing. The optical mark 28a on the disc 28 is used to detect the rotational speed of the upper shaft of the sewing machine, and the optical mark 28b is used to detect the upper position of the needle. Also, as shown in Fig. 3, the optical mark disk 2
8 is formed with a rotation stopper 28C, which fixes the collar 18 at a predetermined angular position.

Further, in FIG. 1, sensor blocks 32.
34 is arranged, the sensor block 32 is fixed to the sensor block 34 by a positioning protrusion 36, the sensor block 34 is fixed to the pace 12 by a positioning protrusion 38, and both blocks 32 and 34 are fixed to the base by a fixing screw 48. It has been concluded in 12.

A pair of a light emitter 40a and a light receiver 40b, and a pair of light emitters 42a and 42b are provided on the surface of the sensor block 32 facing the optical mark disk 24, and the light emitter 40a and the light receiver 40b are used to cut the thread. The optical mark 24b for timing detection is photoelectrically detected, and the optical mark 24a for detecting the lower position of the needle is photoelectrically detected by the light emitters 42a and 42b. Similarly, a light emitter 44a and a light receiver 44 are provided on the surface of the sensor block 34 facing the optical mark disk 28.
A pair of light emitters 46Jl and a light receiver 46b are provided, and the optical mark 28b for detecting the upper position of the needle is photoelectrically detected by the light emitter 441 and the light receiver 44b. An optical mark 28a for detecting the rotation speed of the upper shaft of the sewing machine is photoelectrically detected by 46b. In addition,
The sensor blocks 32 and 34 each have a printed circuit board 47a mounted with electric circuits related to each light emitter and receiver.
, 47b are attached.

In the above configuration, depending on the model of the sewing machine, the optical mark disk 24 or 28 selected according to the usage condition is attached to the color 1.
8, adjust the angular position and fix as described above. Then, the coupling shaft 10 rotates together with the upper shaft of the sewing machine, and the optical mark discs 24.28 also rotate due to this force, and the optical marks 24Jl, 24 of each disc 24.28
b% 28a% 28b are photoelectrically detected by the respective light emitters and light receivers, and the rotation detection signals for each of the above-mentioned purposes are obtained from each light receiver.

Here, unlike conventional ring magnets, the optical mark disks 24 and 28 have no problem even if they are small in thickness, and are extremely light and compact, allowing the entire detector to be made smaller and lighter. However, the reliability of the detection operation does not decrease due to the reduction in size and weight. In addition, optical mark disk 2
Since the 4.28 is small and lightweight, its moment of inertia is extremely small, and there is no risk of mechanical damage to rotating parts even in recent high-speed sewing machines.
Since the positions of the optical mark disks 24 and 28 can be adjusted simultaneously and the position of the optical mark disk 24 can be adjusted independently, the detection operating point can be adjusted very easily. Furthermore, since the optical mark disks 24 and 28 can be easily attached and detached together with the collar 18, it is possible to easily adapt to changes in the model of the sewing machine and the manner in which it is used.

In addition, without using the collar 18.20, the optical mark disk 2
4.28 can also be directly fitted onto the coupling shaft 10 so that the angular position can be adjusted by slip rotation. Further, only one optical mark disk tli may be used, and in that case, optical marks can be formed on the front and back sides of the disk.

Furthermore, it goes without saying that the relationship between the non-reflective surface and the reflective surface of the optical mark may be reversed to that in the embodiment.

As explained in detail above, according to the rotation detector for a sewing machine according to the present invention, it is possible to realize a detection operation that is small, lightweight, highly accurate, and highly reliable, and the detection operation point can be easily adjusted. .

[Brief explanation of drawings]

FIG. 181 is a cross-sectional view of a rotation detector for a sewing machine according to an embodiment of the present invention, and FIGS.
4.28 is an explanatory diagram. In each figure, the same members are given the same symbols, 10 is the coupling shaft, 12 is the pace, 24, 28 is the optical mark disk, 2
4 a, 24 b, 28 a, 28 b are optical marks, 40 a, 42 m, 44 a, 46
a is a light emitter, and 40b, 42b, 44b, and 46b are light receivers. Agent: Patent attorney Shin Kuzuno - (1 other person)

Claims (4)

[Claims] (1) A pace fixed to the sewing machine body; a coupling shaft rotatably held by the pace; one end coaxially connected to the sewing machine shaft; and a coupling shaft that rotates integrally with the sewing machine shaft; an optical mark disk coaxially attached to the optical mark disk, and a light emitter and a light receiver arranged at the space opposite the optical mark disk to detect optical marks formed concentrically on the optical mark disk. Rotation detector for sewing machines equipped with a device. (2) 4! In the rotation detector for a sewing machine according to claim (1), a plurality of series of optical marks that do not overlap each other are formed concentrically on the optical mark disk, and each series of optical marks corresponds to the optical mark of each series. A rotation detector for a sewing machine, characterized in that the above light emitter and light receiver are provided. (3) A rotation detector for a sewing machine according to any one of claims (IL) (2), characterized in that two of the optical mark discs are attached to the coupling shaft. . (4) The rotation detector for a sewing machine according to claim (1), wherein the optical mark disc is attached to the coupling shaft such that its angular position can be adjusted. .