JPH0443943Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to a photoelectric switch constructed by attaching photoelectric elements such as a light projecting element and a light receiving element to a frame.

(b) Prior Art In the photoelectric switch mentioned above, it is necessary to make the space between the photoelectric element and the lens airtight to prevent dust from entering and moisture from entering. As shown in FIG. 3, when fitting the shield plate 3, the optical filter 4, and the photoelectric element 5 to the L-shaped holding frame 2 that is continuously formed on the frame 1 and faces each other, the shield plate A rubber gasket 6 was inserted between the frame 1 and the frame 1.

The rubber packing 6 interposed between the frame 1 and the shield plate 3 is compressed in the direction of reducing its thickness, so that it absorbs the variation in dimensions of each part 3, 4, and 5, and uses its elasticity to The joint surfaces of the parts are brought into pressure contact, and the airtight state of the photoelectric element mounting area is maintained.

However, when the gasket 6 is inserted and fitted, the gasket 6 becomes misaligned and blocks the transmission of light, reducing the amount of light emitted and the amount of light received, which has a large effect on the detection distance.

For this reason, when attaching the photoelectric element to the frame, it is necessary to adjust the position of the gasket correctly, which has the disadvantage that the attaching operation requires a lot of effort and time.

(c) Problems to be solved by the invention The object of this invention is to provide a photoelectric switch in which a photoelectric element can be hermetically fitted to an element holding part of a frame without using a gasket.

(d) Means for solving the problem This invention consists of a box-shaped element with an opening on one side on the back side of the part of the frame where the light transmission hole is formed, and a width that can accommodate the element and its accessory parts. A holding part is formed in a continuous manner, and the width formed by the protrusion and the frame is set so that the element to be stored and its accessory parts are pressed into contact with the frame on the inner wall surface of the element holding part facing the light transmission hole. The photoelectric switch is characterized in that the width of the photoelectric switch is set to be smaller than the width formed by the element and its accessory parts, and a protrusion is formed in series so that the head is crushed when the device is stored.

(e) Effects of the invention According to this invention, the width of the element holding part of the frame for holding the element and its accessory parts is set small by the protrusion whose head is crushed by press-fitting, so that the element and its accessory parts are held small. When the accessory is press-fitted into the element holding part, the head of the protruding strip provided on the element holding part is crushed by the required amount, and the joint surfaces of the press-fitted element and its accessory parts and the frame are in pressure contact. This maintains an airtight state between each component. At the same time, the above-mentioned collapse of the protruding head portion absorbs variations in the dimensions of the press-fitted parts.

Therefore, dust and moisture can be prevented from entering between the parts without using rubber gaskets as in the conventional case.

Furthermore, since no gasket is required, the transmission of light is not obstructed, and a decrease in the amount of light emitted or received can be prevented, improving reliability.

Further, since the elements can be easily held without requiring much time or effort, and the mounting position is determined by the holding part, work efficiency during production is also improved.

Furthermore, since no rubber packing is required, the number of parts can be reduced.

(E) Example of the invention An example of the invention will be described below in detail based on the drawings.

The drawings show a photoelectric switch, Figures 1 and 2.
In the figure, 11 is a frame, and this frame 1
A light transmitting hole 13 is formed in the thick portion 12 of the light transmitting member 1, and a lens 15 is attached to the large diameter portion 14 of the light transmitting member 13 by bonding.

Reference numeral 16 denotes a box-shaped element holding portion with an open top, and this element holding portion 16 is formed continuously on the back side of the thick portion 12 described above.

On the inner wall surface 17 of the element holding portion 16 facing the light transmission hole 13, two longitudinally parallel protrusions 18, 18 are provided in series. The height of the protrusions 18, 18 is determined by the width between the tips of the protrusions 18, 18 and the back surface of the thick portion 12.
Shield plate 19 and optical filter 2 stored in 6
0, the light emitting element (or light receiving element) 21 is set to be smaller than the total.

The operation and effects of the photoelectric switch constructed as above will be explained below.

First, the shield plate 19 and the optical filter 20 are inserted into the element holding part 16 having an upper opening.

At this time, the position of the hole 22 in the shield plate 19 is determined by the left and right walls and the bottom plate of the element holding part 16.

Next, the light emitting element 21 is press-fitted, and the projections 18 and 1 on the inner wall surface 17 of the element holding part 16 are
8 is crushed, and due to the compressed elasticity, each part 19, 20, 21 is closely fitted to the frame 11, and at the same time, variations in component dimensions are absorbed.

Therefore, it is possible to prevent dust and moisture from entering between the parts without using rubber gaskets, and since no gaskets are required, the transmission of light is not obstructed, reducing the amount of light emitted and received. can also be prevented, improving reliability.

Moreover, the shield plate 19, the optical filter 20,
Since the position of the element 21 is simply and easily determined to the normal position with respect to the lens 15 and the light transmission hole 13,
It is possible to easily attach the elements without much effort or time, and it is also possible to improve productivity.

Furthermore, since there is no need for rubber gaskets,
It is possible to reduce the number of parts.

[Brief explanation of the drawing]

The drawings show an embodiment of this invention; FIG. 1 is a perspective view of a photoelectric switch, FIG. 2 is a cross-sectional plan view of the main parts, and FIG. 3 is a perspective view of a conventional example. 1... Frame, 13... Light transmission hole, 16...
Element holding portion, 17...Inner wall surface, 18...Protrusion, 2
1...Photoelectric element.

Claims (1)

[Claim for Utility Model Registration] On the back side of the part of the frame where the light transmission hole is formed, a box-shaped element holding part with an opening on one side and a width that can accommodate the element and its accessory parts is formed in series. Then, in order to press the element and its accessory parts to be stored on the inner wall surface of the element holding part facing the light transmission hole toward the frame side, the width between the protrusion and the frame is set so that the element and its accessory parts are A photoelectric switch that is set smaller than the width of the parts and has a series of protrusions whose head is crushed when the switch is stored.