JPH071717Y2 - Reflective photoelectric switch - Google Patents

Description

TECHNICAL FIELD The present invention relates to a reflective photoelectric switch.

[Background technology]

As one of the photoelectric switches, there is a reflection type photoelectric switch configured to detect the presence or absence of only an object within a certain distance range from the switch.

FIG. 4 and FIG. 5 show one of conventional reflection type photoelectric switches. This switch, as shown in the figure,
An L-shaped light projecting side holder 2 having a light projecting lens 1 for projecting light from a light emitting element (not shown), and a light receiving lens 3 for making light incident on a light receiving element (not shown). It has two holders of the light-receiving side holder 4 provided with. Both of the holders 2 and 4 are assembled in advance to be one unit body before being incorporated into the main body case 5. The light emitted from the light projecting lens 1 strikes the object to be detected and is reflected, and the reflected light enters the light receiving element through the light receiving lens 3.

In this reflective photoelectric switch, the reflected light is incident on the light receiving element only when the object is within a certain distance range from the switch, and in other cases, the reflected light is not incident and the switch does not operate. ing. In such a switch, a means for moving the range back and forth with respect to the switch is formed as needed. As this means, the light receiving side holder 4 is set so as to move vertically with respect to the light projecting side holder 2, and the rotation transmitting member 6 having the fitting hole 6a is arranged at the upper end of the light projecting side holder 2, and The light receiving side holder 4 is provided with an engaging projection 7 having an engaging groove 7a that engages with a spiral cam 6b provided on the outer periphery of the member 6. That is, the light projecting lens 1, the light emitting element and the light receiving element are fixed, and the light receiving lens 3 is moved. An insertion hole 8 is formed in the upper side wall 5a of the main body case 5, and the fitting piece 9a of the adjusting knob 9 fitted in the insertion hole 8 is fitted in the fitting hole 6a. . When the adjusting knob 9 is rotated, the rotation transmitting member 6 rotates in the normal and reverse directions. Since the cam 6b is formed in a spiral shape, the light-receiving side holder 4 moves up and down as the member 6 rotates. In this case, the entire length of the cam 6b is determined so as to move the light-receiving side holder 4 up and down within the rated range defined as the detection area variable range.

By the way, two spring supporting protrusions 4a are provided on the upper portion of the light-receiving side holder 4, and the spring 10 is fitted into these protrusions 4a. The spring 10 is set in advance in the optical block, and when incorporated in the holder case 5, the spring 10 elastically contacts the upper side wall 5a of the case 5 to act as a compression spring. The spring 10 corresponds to the entire length of the cam 6b,
The light-receiving side holder 4 is constantly pushed down, so that the backlash is eliminated between the cam 6b and the engaging groove 7a, and the adjustment is surely performed. The cam 6b is designed so that the entire length thereof can be adjusted within the rated range, and the spring 10 always acts while the cam 6b is engaged with the engagement groove 7a. When assembled in the case 5, the cam 6b and the engaging groove 7b are kept engaged, and the spring 10 is assembled, the upper wall 5a of the main body case 5a.
It has a natural length that is equivalent to. As a result, when the optical block is installed in the main body case 5, it is necessary to install the spring 10 while shrinking it, which not only makes the work troublesome and takes time, but also causes the spring 10 to bend, which causes the switch to operate. There were times when it became uncertain.

[Purpose of device]

In view of the above circumstances, the present invention is capable of easily and surely incorporating the optical block in the main body case without the spring hitting the main body case, and the spring is bent at the time of assembling, resulting in uncertain operation. It is an object of the present invention to provide a reflective photoelectric switch that does not become worn.

[Disclosure of device]

In order to achieve the above-mentioned object, the present invention has a body case,
A light projecting side holder having a light projecting lens and a light receiving side holder having a light receiving lens are incorporated as one unit body, and one of the two holders is provided with a rotation transmitting member. A helical cam provided on the transmission member engages with the other holder so that the rotation operation of the rotation transmission member causes the other holder to move linearly with respect to the mating holder, and In the reflective photoelectric switch in which a spring is mounted, and the holder is always biased in one direction by receiving one end of the spring by the main body case, the spiral cam can change the detection area. An auxiliary cam that is adapted to respond to the other holder within the rated range specified as the range and that engages with the other holder outside the rated range is used as the cover. To be provided continuously, when the other holder is engaged with the auxiliary cam, said spring is summarized as reflection type photoelectric switch, characterized in that has a natural length.

Hereinafter, the present invention will be described in detail with reference to the drawings showing an embodiment thereof.

FIG. 1 is a perspective view showing a state when assembling an embodiment of a reflection type photoelectric switch according to the present invention.
The figure shows the state after assembly. In these figures,
Members and portions denoted by the same reference numerals as in FIGS. 4 and 5 are the same or substantially the same.

By the way, in this case, the cam 6b abutting on the outer peripheral surface of the cylindrical rotation transmitting member 6 has a spiral shape so as to exactly correspond to the rated range as shown in FIGS. 3 (a) and 3 (b). The auxiliary cam 6c is integrally formed so as to be continuous in the horizontal direction from the minimum value min position of the cam 6b (the movement amount of the light-receiving side holder 4 is minimum). Also,
A contact protrusion 9b is formed on the outer periphery of the adjusting knob 9, while a stopper 8a against which the contact protrusion 9b abuts is provided in the insertion hole 8 formed in the upper side wall 5a of the main body case 5. When the hitting protrusion 9b hits one side of the stopper 8a, the maximum value max position of the cam 6b is located in the engaging groove 7a, and when the adjusting knob 9 rotates and the hitting protrusion 9b hits the other side of the stopper 8a. The position of the minimum value min is located in the engagement groove 7a. That is, the contact protrusion 9b and the stopper 8a function to define the rated range.

The optical block is preset so that the auxiliary cam 6c is located in the engagement groove 7a. As a result, the light-receiving side holder 4
Is pushed down so as to correspond to the rated range or less, so that even if the block is incorporated as it is, the spring 10 has a natural length and does not reach the upper side wall 5a of the main body case 5. Therefore, even if the optical block is built in the main body case 5 as it is, the spring 10 does not
It is something that does not hit. After assembly, adjust knob 9
Is inserted into the insertion hole 8 so that the hitting protrusion 9b does not hit the stopper 8a, and the fitting piece 9a is fitted into the fitting hole 6a. By rotating the adjusting knob 9 as it is to rotate the rotation transmitting member 6, the engagement groove 7a is
The positions of the minimum value min of the auxiliary cam 6c and the cam 6b correspond. As a result, the portion of the cam 6b corresponding to the rated range is engaged with the engagement groove 7a, the light-receiving side holder 4 is lifted, and the spring 10 comes into a compressed state by hitting the upper side wall 5a. It works to prevent backlash. In this state, the hitting protrusion 9b comes to a position not corresponding to the stopper 8a, so that the adjusting knob 9 is fully inserted into the insertion hole 8 and the lower fitting piece 9a is fitted into the fitting hole 6a at a proper position. To fit.

In this way, the spring 10 is prevented from hitting the main body case 5 by the auxiliary cam 6c, so that the optical block can be surely assembled into the main body case 5 in a short time, and the spring 10 is pushed down during the assembly. As a result, there is no risk of the spring 10 bending,
The 10 always operates normally, and the backlash prevention function will be achieved in a stable and reliable manner.

The light emitting element may be provided in the light projecting side holder 2 or may be provided separately from the light projecting side holder 2. It may be provided separately from the optical block. The light receiving element may be provided in the optical block or may be provided separately from the optical block.

This invention is not limited to the above embodiment. For example, the spiral cam may have a groove shape instead of a ridge so as to engage with a mating protrusion. Further, in the above embodiment,
Although the light receiving lens is moved, the light receiving lens may be fixed and the light projecting lens may be moved.

[Effect of device]

Since the photoelectric switch according to the present invention has the configuration described above, the spring does not hit the main body case,
The optical block can be easily and surely installed in the main body case, and the spring does not bend during installation, so that the backlash prevention function is not impaired.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state when assembling an embodiment of a reflection type photoelectric switch according to the present invention, and FIG.
Sectional view showing a state immediately after assembly, FIG. 3 (a),
(B) shows a rotation transmission member, (a) is a plan view and (b) is a front view. FIG. 4 is a perspective view showing a state when a conventional reflection type photoelectric switch is assembled, and FIG. 5 is a sectional view showing a state after the assembly. 1 ... Emitting lens, 2 ... Emitting side holder, 3 ... Receiving lens, 4 ... Receiving side holder, 5 ... Main body case, 6
...... Rotation transmission member, 6b …… Cam, 6c …… Auxiliary cam, 7a…
… Engagement groove, 10 …… Spring

Claims (1)

[Scope of utility model registration request] 1. A light-transmitting-side holder having a light-projecting lens and a light-receiving-side holder having a light-receiving lens are provided in a main body case.
As one unit body, one of the two holders is provided with a rotation transmission member, and the spiral cam provided on this rotation transmission member engages with the other holder to rotate the rotation transmission member. Causes the other holder to move linearly with respect to the mating holder, and a spring is attached to the other holder, and one end of this spring is received by the main body case so that the holder is always in one position. In the reflection type photoelectric switch adapted to be biased in the direction, the spiral cam is adapted to respond to the other holder within a rated range defined as a detection range variable range, and An auxiliary cam that engages with the holder outside the rated range is provided continuously to the cam, and when the other holder is engaged with this auxiliary cam, Reflective photoelectric switch in which the spring is characterized in that has a natural length.