JPH0127243Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Target Technical Field" This invention relates to an improvement of a so-called vane type photoelectric switch.

"Conventional Device and Its Disadvantages" A conventional photoelectric switch of this type is shown in FIG. 4. That is, a pair of legs 3 of a die-cast housing 1 having a U-shaped housing portion 2,
3, inner walls 3a, 3a facing each other
is provided with a light emitting window 3b and a light receiving window 3c, respectively, but at this time, through holes 3e, 3e concentric with both windows 3b, 3c are simultaneously formed in the outer walls 3d, 3d by a drill, and A translucent cap 10 is fitted into the caps 3b and 3c, and the through holes 3e and 3e are covered with covers 12 and 12, respectively. And inside the legs 3, 3 is a printed circuit board 1.
1 and 11 are guided and accommodated in the grooves 3f and 3f,
One printed circuit board accommodates a light emitting element 13 corresponding to the light emitting window 3b, and the other printed circuit board accommodates a light receiving element 14 corresponding to the light receiving window 3c.

Moreover, in the one shown in FIG. 5, in the leg parts 3, 3,
Windows 3b, 3 are provided on the inner walls 3a, 3a facing each other.
Cap 1 which forms a window b and has translucency in this window.
0 and 10 are fitted through an O-ring 38 and further fixed with washers 41, while a U-shaped printed circuit board 11 is accommodated in the housing chamber 2, and the legs 11a, 11a of this board are Light projecting element 1
3 and a light-receiving element 14, and as shown in FIG. Light receiving element 1
A flexible printed circuit board 11b for shielding is wrapped around the outer periphery of 4.

However, in the case shown in FIG. 4, the light emitting window 3b and the light receiving window 3c cannot be formed at the same time when the housing 1 is molded due to the mold, and therefore are formed by a drill after the housing 1 is molded. It is necessary to drill through holes 3e and 3e which are necessary and unnecessary in the first place, and these through holes need to be closed again with the cover 12 etc. after being drilled.
Not only does it require a lot of man-hours, but it also has the disadvantage of reducing sealing performance.Also, since there is play between the printed circuit board 11 and the housing 1, Accurate positioning is difficult, and two printed circuit boards 11 are required, one on the light emitting side and the other on the light receiving side, which increases the cost.Moreover, the inside of the legs 3 is narrow and the printed circuit board 11 cannot be accommodated. There is not enough space for electrostatic shielding, and the shape of the fitting surface between the housing 1 and the cover 33 is complicated, and the opening area of the housing 1 is wide, so it is not possible to obtain sufficient sealing performance. There is.

In addition, in the case of those shown in FIGS. 5 and 6, the light emitting/receiving elements 13 and 14
Since the caps 10, 10 are fitted in the windows 3b, 3b, it is more difficult to position each one, and the shape of the printed circuit board 11 is complicated, so the entire It is nearly impossible to provide electrostatic shielding, and the electrostatic shielding of particularly sensitive photodetectors becomes incomplete. In addition, the housing 1 is similar to that shown in FIG.
Since the shape of the fitting portion between the housing 1 and the cover 33 is complicated, and the opening area of the housing 1 is large, sufficient sealing performance cannot be obtained.

[Objective] The purpose of this invention is to eliminate such conventional drawbacks and provide a photoelectric switch that is highly reliable and easy to assemble.

``Example'' An example of this invention will be described below with reference to the drawings.

That is, in FIGS. 1 and 2, a die-cast housing 1 is provided with a relatively wide rectangular storage chamber 2 with an open upper surface at one end, and a pair of cylindrical parts 3 forming the storage chamber at the other end. 2, and protrudingly provided at a predetermined interval from each other,
As a result, it is formed into a U-shape as a whole. A plastic inner case 5 is accommodated in the storage chamber 2, and this inner case is positioned by protrusions 6, 6 provided at the bottom of the storage chamber 2. Element housing portions 7 and 8 are provided at the other end of the inner case, that is, in the portions of the cylindrical portions 3 and 3 that are close to the holes 4;
Furthermore, a display element accommodating part 9 is provided adjacent to one of the element accommodating parts. A printed circuit board 11 forming an electronic circuit is housed in the inner case 5 in a fitted state, and a light emitting element 13, a light receiving element 14, and an operation display element 15 are attached to this printed circuit board, and these elements are printed circuit board 11
In the fitted state with respect to the inner case 5, it is accommodated in the element accommodating parts 7, 8 and the display element accommodating part 9, and is positioned by these element accommodating parts. A display window 16 is provided on the side wall of the housing 1 in correspondence with the operation display element 15, and a translucent cap 18 is attached to this window via an O-ring 17. Also, a cable 2 drawn into the interior of the housing 1 through a hole 21 provided at one end thereof.
2 is connected to the printed circuit board 11 and retained in the housing 1 by a seal 23 and a bushing 24. Also fixed to the printed circuit board 11 is an electrically conductive resilient contact piece 25 connected to its ground conductor, with both free ends extending away from both sides of the board. Further, the opening of the inner case 5 is covered with an inner cover 27.
A shallow recess 29 for positioning the cushion material 28 is formed on the outer surface of the inner cover. In addition, protrusions 31 are provided at the periphery of the opening of the storage chamber 2.
31 are provided, and these protrusions are provided with gaskets 32.
A die-cast outer cover 33 is fitted through the housing 1, and by caulking the projections 31, 31, the cover 33 is fixed to the housing 1 and airtightly covers the opening thereof. Further, a conductive thin film is formed on the inner wall surfaces of the inner case 5 and the inner cover 27 by, for example, vapor deposition, and comes into electrical contact with the elastic contact piece 25 when the inner case 27 is attached.

Inside the cylindrical parts 3, 3 are rod-shaped light guides 35, 3 made of a translucent material such as acrylic or glass.
5 is accommodated. These light guides are provided with a narrow groove 36 along the periphery at one end thereof, and a head 37 at the other end. These light guides are inserted into the cylindrical parts 3 from the other end, one end of which protrudes into the housing chamber 2, and the head 37 is inserted into the cylindrical part 3 through an O-ring 38.
It is adapted to engage with the stepped portion 39 of. In this state, the stopper 41 engages with the narrow groove 36 and the wall of the storage chamber 2, thereby preventing the light guide 35 from falling out. Further, at one end of this light guide, a mirror portion 43 corresponding to the light emitting element 13 or the light receiving element 14 is provided.
And at the other end, that is, inside the head 37, there is a mirror section 4.
Another mirror portion 45 corresponding to No. 3 is formed. Further, both of these mirror parts have windows 4 provided on the inner walls facing each other at the other ends of the cylindrical parts 3, 3.
They correspond to each other through 6. Therefore, one end of one light guide optically faces the light projecting element 13, and one end of the other light guide optically faces the light receiving element 14, and both mirror parts 45, 4
5, the optical axes of both light guides 35, 35 coincide with each other. Furthermore, a cap-shaped mirror cover 47 is provided on both mirror parts 45,45.

In another embodiment of this invention shown in FIG. 3, one end of the light guides 35, 35 is finished, that is, no mirror portion is provided, and the optical axes of the light projecting element 13 and the light receiving element 14 are connected to the light guides 35, 35. The optical axis of the lens is made to coincide with the optical axis of No. 35.

"Effects" As described above, this device houses the rod-shaped light guides 35 in the cylindrical portion 3, and connects one end of one of these light guides to the light projecting element 13, and connects one end of the other light guide to the light projecting element 13. Since one end is optically opposed to the light-receiving element 14, and a mirror part 45 is provided at the other end side of both light guides 35, 35 to align the optical axes of these two light guides, the electric circuit part can be assembled on one side of the housing 1, that is, there is no need to provide light emitting/receiving elements at the ends of the cylindrical parts 3, 3, so there is no need to use multiple printed circuit boards, and the printed circuit board can be made smaller. Therefore, the area of the electrostatic shield is extremely small, and the cylinder parts 3, 3 can be made smaller.Furthermore, since the number of sealing parts is small, the sealing performance is extremely good.

[Brief explanation of the drawing]

Figure 1 is a front sectional view of the photoelectric switch in this invention, Figure 2 is an exploded perspective view, Figure 3 is a front sectional view showing another embodiment of this invention, and Figures 4 and 5 are conventional photoelectric switches. FIG. 6 is an exploded perspective view of the switch, and is a front sectional view showing the optical path of the photoelectric switch in FIG. DESCRIPTION OF SYMBOLS 1...Housing, 2...Accommodation chamber, 3...Cylinder part, 4...Hole, 5...Inner case, 6...Protrusion,
7... Element accommodating part, 8... Element accommodating part, 9... Display element accommodating part, 11... Printed circuit board, 13
... Light emitting element, 14 ... Light receiving element, 15 ... Operation display element, 16 ... Display window, 17 ... O ring,
18... Cap, 21... Hole, 22... Cable, 23... Seal, 24... Bush, 25...
...Elastic contact piece, 27...Inner cover, 28...Cushion material, 29...Recess, 31...Protrusion, 32
...Packskin, 33...Outer cover, 35...Light guide, 36...Small groove, 37...Head, 38...
O-ring, 39...Step, 41...Stopper, 43
...Mirror part, 45...Mirror part, 46...Window.

Claims (1)

[Scope of utility model registration request] A light emitting element 1 is housed in a U-shaped housing 1 in which a pair of cylindrical parts 3, 3 are protruded from each other at a predetermined interval.
3 and the light receiving element 14, and a rod-shaped light guide 35 is housed in each of the cylinder parts 3, and one end of one of the light guides is connected to the light projecting element 13, Further, one end of the other light guide is optically opposed to the light receiving element 14, and a mirror portion 45 is provided on the other end side of each of the light guides 35 to align the optical axes of both light guides with each other. Photoelectric switch.