JPH0111189Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to a detection device for a sewing machine.

[Prior art] In a conventional sewing machine detection device, a detector having a light emitting means and a light receiving means is fixed to the sewing machine frame, and a reflective sensor with a color scheme such as white or black is applied between the sewing machine frame and the pulley. A plate was installed, and detection was based on the difference in reflection efficiency.

[Problems to be solved by the invention] The conventional sewing machine detection device described above detects only the difference in the reflection efficiency of the color scheme on the same plane of the reflector, so the difference in the intensity of the reflected light is small and can cause errors. There was a high possibility that ivy detection would occur. In addition, the reflector was required as a separate component, resulting in high costs and a large number of assembly steps.

[Purpose of the invention] This invention was made to solve the above problems, and it is possible to solve not only the difference in reflection efficiency depending on the color but also the difference in the distance from the detector to the reflective surface and the distance to the non-reflective surface. In addition, the purpose is to increase the difference in the intensity of reflected light from both sides, thereby reducing the possibility of erroneous detection. Furthermore, by providing the pulley with the function of a reflector, the number of parts can be reduced, and costs and assembly processes can be reduced.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, concave portions and convex portions that are uneven in the axial direction of the main shaft are arranged side by side in the rotational direction on the surface of the pulley on the side of the sewing machine frame. The concave portion is dark-colored, and the end surface of the convex portion on the detector side is formed into a mirror-like surface to serve as a reflecting plate.

[Function] With the above configuration, the light emitted from the light emitting means of the detector is reflected by the end face of the convex part of the pulley that acts as a reflecting surface and enters the light receiving means, and the reflection efficiency is poor in the recessed part of the pulley that acts as a non-reflecting surface. Furthermore, the path of the reflected light is different due to the difference in distance, so that almost no light is reflected to the light receiving means. Therefore, since there is a large difference in the intensity of reflected light between the convex portion and the concave portion of the pulley, erroneous detection is less likely to occur. Additionally, a reflector plate as a separate component is not required, reducing costs and assembly steps.

[Example] An example embodying the present invention will be described below with reference to the drawings.

Reference numeral 2 denotes a main shaft that moves the sewing machine needle up and down, and is rotatably supported by a bearing 1a that is integrally structured with the sewing machine frame 1.

4a, 4b, and 4c are detectors having a light emitting means and a light receiving means, which are fixed to a substrate 5, covered with a detector cover 6 except for the detection surface, and screwed through a ring-shaped holding device 7. 8 and is fixed to the bearing 1a.

A pulley 3 receives power transmitted from a motor (not shown) through a belt 9, and is fixed so as to rotate integrally with the main shaft 2. This pulley 3 has concave and convex portions 3a, 3b, 3c and convex portions 3d, 3e, 3 which are uneven in the axial direction of the main shaft and are arranged side by side in the rotational direction.
The uneven parts 3a and 3d are located opposite to the detector 4a to control the rotation speed, the uneven parts 3b and 3e are located opposite to the detector 4b to control the needle lower position, and the uneven parts 3c,
3f is located opposite to the detector 4c and detects the needle top position.

Concave portions 3a, 3b, 3c and convex portions 3d, 3e, 3f
is integrally formed on the surface of the sewing machine frame when the pulley 3 is cast. Next, a dark color is applied to the entire surface, and then a mirror finish is applied except for the concave portions, so that the concave portions act as non-reflective surfaces and the convex portions act as reflective surfaces. In this embodiment, the entire portion except the recessed portions is mirror-finished, but this effect can be achieved if at least only the convex portions 3d, 3e, and 3f within the two-dot chain line shown in FIG. 2 are mirror-finished.

The detector 4a detects the convex portion 3d as shown in A of FIG.
When facing the light projecting means 4a-1, the light emitted from the light projecting means 4a-1 is reflected by the convex portion 3d and is reflected by the light receiving means 4a-2.
to go into. The detector 4a is located in the recess 3 as shown in FIG.
When facing the light receiving means 4a-2, the reflected light is attenuated because the concave portion is dark-colored, and furthermore, since the distance between the reflecting surface and the detector is different, the path of the light is also different, and the light enters the light receiving means 4a-2. becomes very weak.

FIG. 5 shows another embodiment, in which the bottom surface of the concave portion 3a is inclined with respect to the end surface of the convex portion 3d. In this case, when the detector 4a is in a state facing the recess 3a, the path of the reflected light is further deviated than in the case of B in FIG. 4, so that the light entering the light receiving means 4a-2 becomes even weaker.

[Effects of the invention] As detailed above, in the present invention, concave portions and convex portions that are uneven in the axial direction of the main shaft are arranged side by side in the rotational direction on the surface of the pulley on the side of the sewing machine frame, and the concave portions are dark-colored and the convex portions are arranged side by side in the direction of rotation. Since the end face of the portion is mirror-finished to serve as a reflecting plate, it is possible to reduce the possibility of erroneous detection due to a large difference in the intensity of reflected light between the convex portion and the concave portion. Furthermore, since there is no need to manufacture the reflector as a separate component, it is possible to reduce the cost and assembly process due to a reduction in the number of parts.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment embodying the present invention;
Figure 2 is a sectional view taken along the line X-X in Figure 1, and Figure 3 is a cross-sectional view of Figure 1.
FIG. 4 is a diagram showing the relationship between the Z-Z line enlarged sectional view of FIG. 2 and the detector, and FIG. 5 is a diagram corresponding to FIG. 4 of another embodiment. In the figure, 1 is a sewing machine frame, 2 is a main shaft, 3 is a pulley, 3a, 3b, 3c are recesses, 3d, 3e, 3f
is a convex portion, and 4a, 4b, and 4c are detectors.

Claims (1)

[Claims for Utility Model Registration] 1. A main shaft 2 which is rotatably supported by a sewing machine frame 1 and moves the needle up and down, a pulley 3 fixed to the main shaft 2 so as to rotate integrally with the main shaft 2, and the pulley 3. Detectors 4a, 4b, and 4c are fixed to the sewing machine frame 1 so as to face each other, and each have a light emitting means and a light receiving means. It has convex portions 3d, 3e, and 3f arranged in the rotation direction, and the concave portions (3a, etc.) are dark-colored to form a detector (4a, etc.) for the convex portions (3d, etc.).
A detection device for a sewing machine, characterized in that a side end face is formed into a mirror surface. 2 The bottom surface of the concave portion (3a etc.) is the convex portion (3d etc.).
The detection device for a sewing machine according to claim 1, wherein the detection device is inclined with respect to the end face of the sewing machine. 3 The uneven portions (3a etc.) and (3d etc.) are the pulley 3
Detection of a sewing machine according to claim 1 or 2 of the utility model registration claim, characterized in that the sewing machine is integrally formed when it is cast, and the end surface of the convex part is mirror-finished after the entire body is dark-colored. Device.