JPS6118476B2 - - Google Patents

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 a 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, which has the disadvantage of making the detector itself large. Because of the large size, there has been a drawback that the rotating parts or magnets are easily damaged, especially in recent high-speed sewing machines. Furthermore, in conventional detectors,
It is extremely troublesome to adjust and change the detection position of the detector depending on the model 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 and lightweight, provides highly accurate detection operation, and allows easy adjustment of the detection position. There is a particular thing.

In order to achieve the above object, the present invention provides slips rotatably stacked on the shaft of a coupling,
two optical mark discs having optical marks concentrically with the axis and at positions that do not overlap; a clamping mechanism fixed to the coupling ring and clamping the optical mark disc set; and a clamping mechanism fixed to the base. ,
A light emitter and a light receiver are provided in the optical mark corresponding areas on both sides of the optical disc set, and the optical mark disc is mounted so that its angular position can be adjusted with respect to the coupling axis. shall be.

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 includes a base 12 fixed to the frame (not shown) of the sewing machine body via a mounting part 12a, and a bearing 1 mounted on the base 12.
4 and 16, and is connected to a shaft end of a sewing machine upper shaft (not shown) through a coupling hole 10a at one end, and rotates integrally with the sewing machine upper shaft. has.

Collars 18 and 20, which are divided into two parts in the axial direction of the coupling shaft 10 and are slip rotatable, are inserted into the tip end 10b of the coupling shaft 10, and the collars 18 and 20 are tightened to the coupling shaft 10 by a fixing screw 22. Fixed. And color 18
Two optical mark discs 24 and 28 are mounted coaxially and in a stacked manner. Optical mark disk 2
4 and 28 are pressed against the flange portion of the collar 18 by a pressing spring 30 as a clamping mechanism whose one end is locked by the collar 20. One optical mark disk 24 is tightly fitted to the collar 18 in a slip-rotatable manner relative to the collar 18, and the other optical mark disk 28 is non-rotatably positioned in the collar 18 as will be described later. There is. 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 and 28 with respect to the coupling shaft 10. The mounting angle position of the mark disk 24 can be adjusted independently. Note that the collar 20 locks one end of the pressing spring 30 and also locks the bearing 1 of the coupling shaft 10.
4, 16 is prevented from coming off.

FIGS. 2 and 3 show the optical mark disk 24.
and 28 optical mark surfaces are shown. The plate surfaces of both discs 24 and 28 are non-reflective surfaces, and light-reflective optical marks 24a, 24b, 28a, and 28b are formed concentrically on the non-reflective surfaces by, for example, printing. Two systems of optical marks 24 are placed on each disk in a concentric manner so as not to overlap each other as shown in the figure.
a and 24b, and 28a and 28b are formed, respectively. The optical mark 24a on the disk 24 is for detecting the lower position of the needle, and the optical mark 24b is for detecting the thread cutting 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. Further, as shown in FIG. 3, a rotation stopper 28c is formed on the optical mark disk 28, thereby fixing it at a predetermined angular position with respect to the collar 18.

Further, in FIG. 1, optical mark disks 24, 2
Sensor blocks 32 and 34 are arranged on both sides of the optical mark side of 8, and the sensor block 32 is fixed to the sensor block 34 by a positioning protrusion 36.
is fixed to the base 12 by a positioning protrusion 38, and both blocks 32, 34 are fixed to the base 12 by a fixing screw 48.
It is fastened to the base 12 by.

A light emitter 40a and a light receiver 4 are provided on the surface of the sensor block 32 facing the optical mark disk 24.
0b and a pair of light emitters 42a and 42b are provided, and the light emitter 40a and light receiver 40b photoelectrically detect the optical mark 24b for thread cutting timing detection. An optical mark 24a for detecting the lower position of the needle is photoelectrically detected. Similarly, a pair of a light emitter 44a and a light receiver 44b, and a pair of a light emitter 46a and a light receiver 46b are provided on the surface of the sensor block 34 facing the optical mark disk 28. The optical mark 28b for detecting the upper position of the needle is photoelectrically detected, and the optical mark 28a for detecting the rotation speed of the upper shaft of the sewing machine is photoelectrically detected by the light emitter 46a and the light receiver 46b. Note that the sensor blocks 32 and 34 each have a printed circuit board 47 mounted with electric circuits related to each light emitter and light receiver.
a and 47b are attached.

In the above configuration, the optical mark disc 24 is selected depending on the type of sewing machine or usage mode.
28 is attached to the collar 18, and the angular position is adjusted and fixed as described above. Then, the coupling shaft 10 rotates together with the upper shaft of the sewing machine, and along with this, the optical mark discs 24, 28 also rotate, and the optical marks 24a, 24b, 28 of each disc 24, 28 rotate.
a and 28b are photoelectrically detected by respective light emitters and light receivers, and the above-mentioned rotation detection signals for each purpose are obtained from each light receiver.

Here, unlike conventional ring magnets, the optical mark discs 24 and 28 have no problem even if they are small in thickness, and are extremely lightweight and compact, making it possible to make the entire detector smaller and lighter. , the reliability of the sensing operation does not decrease due to the weight reduction. Furthermore, since the optical mark discs 24 and 28 are small and lightweight, their moment of inertia is extremely small, and there is no risk of mechanical damage to rotating parts, etc., even in recent high-speed sewing machines. Further, as described above, 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.

Alternatively, the optical mark discs 24, 28 may be fitted directly onto the coupling shaft 10 without using the collars 18, 20, and the angular position can be adjusted by rotating the slip. Furthermore, only one optical mark disc may be used, and in that case, optical marks can be formed on the front and back sides of the disc. 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 described above in detail, the rotation detector for sewing machines according to the present invention can realize accurate and highly reliable detection operation with a small, lightweight, and simple configuration.
Furthermore, the detection operating point can be easily adjusted.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a rotation detector for a sewing machine according to an embodiment of the present invention, and FIGS. 2 and 3 are explanatory views of optical mark discs 24 and 28, respectively. The same members in each figure are given the same reference numerals, 10 is the coupling shaft, 12 is the base, 24, 28 are optical mark disks, 24a, 24b, 28a, 28b are optical marks, 40a, 42a, 44a, 46a are The light emitters, 40b, 42b, 44b, and 46b are light receivers.

Claims (1)

[Scope of Claims] 1. A base fixed to the sewing machine body; A coupling shaft rotatably held by the base, one end of which is coaxially connected to the sewing machine shaft, and rotates integrally with the sewing machine shaft; A coupling shaft. two optical mark discs arranged in a stacked manner so that the slips can rotate around the axis of the disc, and having optical marks concentrically with the axis and at positions that do not overlap; fixed to the coupling ring, and crimping the optical mark disc set a clamping mechanism for clamping, and a light emitter and a light receiver fixed to the base and provided in respective optical mark corresponding areas on both sides of the optical mark disc set, the optical mark disc being attached to the coupling shaft. A rotation detector for a sewing machine, characterized in that it is installed so that its angular position can be adjusted.