JPH0252380B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to improvements in photoelectric switches.

Conventionally, this type of photoelectric switch has a light emitter 1 or a light receiver 2 housed in a case 1, which has a sufficient size compared to the light emitter or receiver, as shown in Fig. 1, and this case is used as an air blower. 20, and air blowing ports 13, 13 are provided in the parts of the cases 1, 1 corresponding to the light passages, and the air blowing device 2
There is a device that prevents dust and dirt from adhering to the lens part of a photoelectric switch by sending air into the cases 1 and 1 from the air outlet 13 and air from the air outlets 13 and 13. Since there is a considerable space between the light emitter 71 or the light receiver 72, the device not only becomes larger as a whole, but also requires an extra amount of air, which is disadvantageous from an energy point of view. In addition, in this type of device, the cases 1, 1 and the emitter 71 or receiver 72
The disadvantage was that mechanical and optical adjustments were extremely troublesome because they were manufactured separately and assembled at the installation site.

The object of the present invention is to solve these conventional drawbacks and provide a photoelectric switch that is easy to handle and has high efficiency.

In order to achieve the object, the present invention accommodates a holder for holding the photoelectric switch body in a case having an opening at one end, covers the opening with a cover, and connects the lens portion of the photoelectric switch body of this cover with a cover. Air outlet on the opposite part,
In addition, air inlets are provided on each wall of the case,
An air guide passage for guiding air from an air inlet to an air outlet is provided in the holder between the cover and the holder.

An embodiment of the present invention will be described below with reference to the drawings.

In other words, case 1 in Figures 2 to 5
An opening 2 is provided at one end, that is, a first wall, and this opening is covered by a cover 3, which is removably attached to the case 1 by screws 4, 4. Further, a block-shaped holder is housed in the case 1, and a recess 6 is formed in this holder along its axis from the first surface side, and a photoelectric switch body 7 is housed in this recess. In addition, a lens portion 8 provided at one end is exposed on the first surface. An air inlet 11 is provided in the second wall of the case 1 adjacent to the cover 3, into which an air hose joint 1 connected, for example, to a compressor (not shown) is provided.
2 are connected. Further, an air outlet 13 is provided in a portion of the cover 3 facing the lens portion 8, and an air outlet 13 is provided between the case 1 and the holder 5 and between the holder and the cover 3. An air guide passage 14 is provided for guiding air. In particular, as shown in FIG.
4 is formed in the first wall surface of the holder 5 by a groove 14a extending in a direction intersecting the axis thereof.

In addition, in a portion of the air guide passage close to the air inlet 11, there is a gap between the inner circumferential surface of the case 1 and the outer circumferential surface of the holder 5, which is centered on the axis of the holder, that is, the axis of the photoelectric switch body 7. An annular air chamber 15 having a rectangular cross section is provided.

In the above configuration, from the air inlet 11 to the air chamber 1
The air flowing into the holder 5 is accelerated in a relatively narrow guide passage 14 formed on the first surface of the holder 5 between the holder 5 and the cover 3, and after being blown onto the lens portion 8, the air flows through the air outlet. It is released to the outside through 13. The lens portion 8 is thereby cleaned.

In the embodiments shown in FIGS. 2 to 5, an opening 2 is provided at one end of the case 1, and this opening is covered with a cover 3. However, the opening 2 is not located at one end of the case 1. There is no problem in providing it at the other end. That is, the air outlet 13 may not be provided on the cover 3 but may be provided directly on one end of the case 1.

Further, in the case of the holder 5 shown in FIG. 5, the groove 14a forming a part of the air guide passage 14 is formed in a band shape so as to extend in the vertical direction.
As shown in FIG. 6, this groove can be constituted by a plurality of grooves 14a, 14a extending radially outward from approximately the axis of the holder 5, or more precisely from the periphery of the lens portion 8.

In this case, the air flowing in from the air inlet 11 is injected onto the outer periphery of the lens portion 8 through this groove,
The air flows out from the air outlet 13 after turning so as to wipe the surface of the lens portion 8 along its circumference.

As described above, this invention accommodates a holder for holding a photoelectric switch body in a case having an opening at one end, covers the opening with a cover, and has an air blower facing the lens portion of the photoelectric switch body of the cover. An air outlet is provided on the wall of the case, and an air guide passage is provided in the holder between the cover and the holder to guide air from the air outlet to the air outlet. The lens portion is constantly cleaned by the high-velocity air flow, which allows a good and stable detection state to be maintained at all times.

Further, since a part of the air guide passage is formed on the wall surface of the holder between the cover and the holder, there is an advantage that it can be formed integrally when molding the holder.

[Brief explanation of drawings]

Figure 1 is a side sectional view of a conventional photoelectric switch;
3 is a side sectional view, FIG. 4 is a cross-sectional perspective view, FIG. 5 is an exploded perspective view, and FIG. 6 is a modified example of the holder, that is, a second holder. It is a perspective view showing an example. 1...Case, 2...Opening, 3...Cover,
4...Screw, 5...Holder, 6...Recess, 7...
...Photoelectric switch body, 8...Lens section, 11...
Air inlet, 12... Air hose joint, 1
3... Air outlet, 14... Air guide passage, 15
...Air chamber.

Claims (1)

[Scope of Claims] 1. A photoelectric switch body is held in a holder, a lens portion of the photoelectric switch body is exposed on a first surface of the holder, and the holder is housed in the case, and the case 1st of
An air outlet facing the lens part of the photoelectric switch main body is provided in the wall of the photoelectric switch, and an air outlet is provided in the second wall of the case, and the first air outlet of the holder is provided between the case and the holder. A photoelectric switch having an air guide passage for guiding air from the air inlet to the air outlet on the surface of the photoelectric switch. 2. The photoelectric switch according to claim 1, wherein an air chamber is provided in the air guide passage between the inner circumferential wall of the case and the outer circumferential wall of the holder. 3. The photoelectric switch according to claim 1, wherein the air guide passage is formed radially around the axis of the holder. 4 Holding the photoelectric switch body in a holder, exposing the lens portion of the photoelectric switch body to the first surface of the holder, and housing the holder in a case having an opening at one end, and Covered with a cover, an air outlet is provided in a portion of the cover facing the lens portion of the photoelectric switch body, and an air inlet is provided in the wall of the case, and between the cover and the holder, the A photoelectric switch in which a holder is provided with an air guide passage for guiding air from the air inlet to the air outlet. 5. The photoelectric switch according to claim 4, wherein the air guide passage is formed radially around the axis of the holder.