JPS588533B2 - Photoelectric switch - Google Patents

Description

[Detailed description of the invention] This invention relates to a photoelectric switch.

In conventional photoelectric switches, a photoelectric element (a light emitting element and a light receiving element are collectively called a photoelectric element) mounted on a printed circuit board and a lens that sets the sensing area of this photoelectric element are installed separately in the main body case. It was configured so that

Therefore, it is difficult to maintain a constant positional relationship between the photoelectric element and the lens, and it is difficult to accurately stabilize the operating characteristics of the photoelectric switch due to the sensitivity region.

In order to eliminate the above-mentioned disadvantages, there is a photoelectric switch in which the mutual positioning of a photoelectric element and lens is performed with high precision using an element holder, and is constructed as shown in FIGS. 1A and 1B, for example.

That is, FIGS. 1A and 1B show a reflective photoelectric switch. 1 is a main body case, and a printed circuit board 2 on which a circuit section is mounted is housed and fixed in a cavity formed in the main body case 1. There is.

The circuit section drives the light emitting element 31 and the light receiving element 32 and performs predetermined signal processing, and is electrically connected to the outside via a cable 7.

The light emitting element 31 and the light receiving element 32 are installed and fixed in a light emitting hood part 41 and a light receiving hood part 42 of the element holder 4, respectively.

Further, on the front surface of the element holder 4, a lens 5 is installed and fixed, in which a light projecting lens 51 and a light receiving lens 52 are integrally formed.

The element holder 4 is inserted into the front opening of the case 1 from the front and fixed with screws 61 and 62 to seal this front opening, with a ring-shaped rubber packing 81 interposed. This improves sealing performance.

Reference numeral 11 is a case force bar that seals the side opening of the case 1.

As mentioned above, the photoelectric switch has a light emitting/receiving element 31.
32 and the light emitting/receiving lenses 51 and 52 are positioned with high precision in the element holder 4, resulting in stable operating characteristics.1 However, in this case, the element holder 4 is fixed to the front opening of the case 1. screw 61.
Since the head of 62 is exposed to the outside at the front, its function may become insufficient if it is corroded by moisture or loosened by mistake, and the sealing performance within the case 1 is impaired. There was a risk that environmental friendliness would deteriorate.

At the front of the case where light is still emitted and received, screw 61.
62 It is not aesthetically pleasing for the head to be visible from the outside.
This has led to inconveniences such as the need to use decorative screws for the screws 61 and 62.

On the other hand, it is also possible to fix the element holder 4 to the case 1 by adhesive or ultrasonic welding instead of using screws.
Adhesives take time to work with, and ultrasonic melting beaks cannot be called an effective method if the case 1 and the holder are made of different materials, such as metal and synthetic resin. .

In view of the above, an object of the present invention is to provide a photoelectric switch that has stable operating characteristics and improved environmental resistance.

That is, according to the present invention, a support is provided inside the main body case that stands upright in a direction perpendicular to the direction in which the element holder is inserted, and a screw hole is formed in the support to connect the support to the socket and the other element holder. A mounting protrusion is integrally formed, and a hole is provided in the mounting protrusion in the upright direction of the support,
The element holder is inserted through the front opening of the main body case and engaged, and a packing is interposed between the element holder and the front opening of the main body case, and the packing is engaged with the hole in the mounting protrusion of the element holder. By tightening the screw into the screw hole of the mounting socket of the support, the element holder is attached to the support in a direction perpendicular to the insertion direction of the element holder, and the element holder crimp the packing to seal the opening. Since the screws are stored in the main body case, they do not corrode and look good, and even if the screws loosen, this loosening does not affect the crimp force of the packing and the element holder The operating characteristics can be stabilized and the environmental resistance can be improved without compromising the sealing performance between the main body case and the front opening of the main body case.

An embodiment of the present invention will be described below with reference to FIGS. 2A, B, and C.

In these drawings, this reflective photoelectric switch is the first
As in the case shown in the figure, a printed circuit board 2 on which a circuit section is mounted is housed and fixed in the cavity of the main body case 1.

This circuit section drives the light emitting element 31 and the light receiving element 32 to perform predetermined signal processing, and is configured with a power transformer 25, an output relay 26, etc., and is housed in the window member 22. A light emitting diode 21 is used to display the operating state of the light emitting diode 21 to the outside.

Further, a time element unit that determines the detection operation time of the circuit section is mounted on a printed circuit board 23 and is housed and fixed in the case 1, and the settings of this time element are adjusted by a volume control 24. There is.

Further, the electrical connection between the circuit and the outside is made by connecting a power cable and a signal cable (
(both not shown) are connected, and the power cable and signal cable are pulled out from the cable tightening ring 71 and 72 portions without impairing the sealing performance inside the case 1. It looks like this.

That is, the power transformer 25 of the circuit section is connected to an external power source via the terminal section 9 and the power cable, and the contact output of the output relay 26 at the time of detection is outputted to the outside via the terminal section 9 and the signal cable. It looks like this.

The light emitting element 31 and the light receiving element 32 are installed and fixed in the light emitting hood part 41 and the light receiving hood part 42 of the element holder 4, respectively.

A lens 5 forming a light projecting lens 51 and a light receiving lens 52 is installed and fixed on the front surface of the element holder 4 by a rectangular ring-shaped holder cover 45.

That is, the holder cover 45 is fixed to the front surface of the element holder 4 and clamps the lens 5, and at this time, the interposition of the ring-shaped rubber packing 82 maintains the sealing performance of the inside of the light emitting/receiving hood portions 41 and 42. It is now possible to

As a result, the mutual positional relationships among the light projecting element 31/light projecting lens 51 and the light receiving element 32/light receiving lens 52 can be easily set with high precision in the element holder 4.

Furthermore, since the inner wall surface of this light-receiving hood portion 42 is formed in a step-like manner, reflected light from outside the detection area is reflected on this inner wall surface and enters the light-receiving element 32, resulting in false detection. Inconveniences are avoided.

The element holder 4 has a mounting protrusion 43 integrally formed between the light emitting hood 41 and the light receiving hood 42.

This electrical switch is assembled as follows.

First, insert the printed circuit board 2 into the case 1 from the side opening of the case 1.
It is inserted and installed inside.

At this time, a cylindrical protrusion 1 formed integrally with the case 1
3 penetrates through the printed circuit board 2 through a predetermined through hole.

A female screw portion is formed at the tip of this protrusion 13 .

A tubular spacer 101 is inserted into the protrusion 13.

The element holder 4 is inserted into and engaged with the front opening of the case 1 from the front.

At this time, the through hole provided in the protrusion 43 of the element holder 4 is positioned above the screw hole at the tip of the protrusion 13, and the screw 100 is inserted into the female thread at the tip of the protrusion 13 through this through hole. By being screwed into the part, the element holder 4 is fixed and the front opening of the case 1 is sealed.

At the same time, the printed circuit board 2 is also tightened and fixed with the screws 100 via the protrusion 43 and the spacer 101.

A ring-shaped rubber packing 81 is interposed in advance at the engagement portion between the element holder 4 and the front opening of the case 1, and the element holder 4 is fixed in a position so as to press the rubber packing 81 slightly.

Therefore, the sealing performance of the front opening of the case 1 is sufficient.

After the printed circuit board 23 has been housed and fixed, predetermined wiring work, etc. have been carried out, the case cover 11 is attached to the side opening of the case 1, thereby completely sealing the inside of the case 1 and completing the assembly work.

As mentioned above, in this photoelectric switch, the light emitting/receiving element 31.
32 and the lenses that control the projection and light reception areas of the light emitting/receiving elements 31 and 320 are precisely positioned with respect to each other in the element holder 4, resulting in stable operating characteristics.

Furthermore, a screw 100 fixes the element holder 4 to the main body case 1.
Since it is sealed in the case 1, it will not be corroded by moisture, chemicals, etc., or accidentally loosened, and is aesthetically pleasing.

Furthermore, the sealing performance of the front opening of the case 1 is affected by the pressure bonding force between the case 1 opening and the engaging portion of the element holder 4, but this pressure force is not obtained by the pressing force of the screw 100 that fixes the device holder 4. do not have.

Therefore, even if the screw 100 becomes loose due to external vibrations, shocks, etc., the sealing performance of the front opening of the case 1 is ensured.

In the embodiment, only the opposite type photoelectric switch was described, but other types of light such as a transmission type photoelectric switch with independent light emitting and receiving sides can be used! It goes without saying that the present invention can be similarly applied to switches.

As described above with respect to the embodiments, according to the present invention, it is possible to provide a photoelectric switch that has stable operating characteristics and improved environmental resistance and durability.

[Brief explanation of the drawing]

FIG. 1A is a front view showing a conventional example, FIG. 1B is a partially sectional side view of the conventional example, FIG. 2A is a front view showing an embodiment of the present invention, and FIG. 2B is a front view showing a conventional example. , C are a side view and a rear view, partially in section, of the same embodiment. 1... Main body case, 2... Printed circuit board, 32...
- Light receiving element, 5... Lens, 13... Projection, 31
. . . Light projecting element, 4 . . . Element holder, 101 .

Claims (1)

[Scope of Claims] 1. A photoelectric element, a lens for controlling a sensitive area of the photoelectric element, a printed circuit board on which a circuit section for driving the photoelectric element and performing temporary signal processing is mounted, and this printed circuit board. A main body case for storing a substrate, an element holder to which the photoelectric element and lens are attached and inserted from a front opening of the main body case to seal the opening, and a relationship between the main body case opening and the element holder. The element holder has a packing interposed in the mating portion, and a mounting receiving part provided as a support that stands upright in the direction perpendicular to the direction of insertion of the element holder inside the main body case and has a screw hole, and the element holder is integrated into the main body case. A mounting protrusion is formed in the mounting protrusion, and a hole is formed in the mounting protrusion in the upright direction of the support, and the element holder inserted into and engaged with the front opening of the main body case is inserted into the mounting protrusion. By tightening the screw that engages the hole in the protrusion into the screw hole in the mounting receptacle of the support,
A photoelectric switch configured such that the element holder presses the packing to seal the opening of the main body case when the element holder is fixed to the mounting receiving part of the support in the insertion direction of the element holder. 2. The photoelectric switch according to claim 1, wherein the mounting receptacle provided inside the main body case is also used for mounting the printed circuit board.