JPH025428Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is used in the field of detection devices that detect the presence of articles such as workpieces.

(Prior art) Proximity switches (for example, see Utility Model Application Publication No. 57-57040) have been used to detect the presence of objects such as workpieces. has been decided,
This has the disadvantage that effective detection is only possible when the distance to the object is within a certain range, and if the dimensions of the object vary, the object will directly hit the tip of the proximity switch and the tip of the proximity switch will There was a problem in that when the plastic member was installed, the plastic member would wear out and become unusable due to disconnection of the internal sensor coil.

(Purpose of the invention) In view of the above problems, by interposing a cushion body between the article to be detected and the detection member of the detector, the dimension of the article in the detection direction (i.e., the thickness of the article) can be reduced by a certain amount. It is an object of the present invention to provide an article detection device that can detect articles without damaging the detector even if the temperature varies, and that has a simple structure and operation that can also be used in work processes in factories. purpose.

(Structure of the invention) The structure of the invention consists of a detector for detecting the presence or absence of an object, such as a machine part being machined or a pressed part, and a moving device for moving the detector back and forth to a detection position where the object is set. The detector is provided with a proximity switch, for example, an electromagnetic type, which is moved forward and backward by the moving device, and is supported so as to be movable back and forth concentrically with the proximity switch, and further includes a front end. a sliding tube having an article-contacting surface that comes into contact with an article; a first spring that always biases the sliding tube forward; The detection plate is detected by the proximity switch as the movable cylinder slides backward, and the detection plate is always urged backward, and if the thickness of the article is uneven, it is compressed according to the thickness. The article detection device is characterized in that it is equipped with a second spring.

(Example) An example of this invention will be described below with reference to the drawings. The detector is composed of a proximity switch, a sliding tube, a first spring, a detection plate, and a second spring. As the proximity switch 1, a conventionally well-known electromagnetic type was used. This proximity switch 1 is fixed to a mounting bracket 2a with a nut 2b, and is held with the front end operating portion 1a of the proximity switch 1 facing forward. Concatenated. A gripping means 2 is constituted by the mounting bracket 2a, the nut 2b, and the fixture 2c. A sliding tube 4 is fitted around the outer periphery of the proximity switch 1 so as to be movable back and forth concentrically with the proximity switch 1.
A sliding tube collar 4a is provided at the middle part of the inner circumference of the sliding tube 4, a spring receiving collar 1b is provided at the middle part of the outer circumference of the proximity switch 1, and a first spring 5 is fitted between the two ribs 1b and 4a. ing. Further, the tip flange 1c provided on the outer periphery of the tip of the proximity switch 1 comes into contact with the sliding tube flange 4a, thereby determining the installation length of the first spring 5, and also determining the longitudinal position of the sliding tube 4 with respect to the proximity switch 1. A cap 6 is attached to the front end of the sliding tube 4, and the front end surface of the cap 6 serves as an article contacting surface 6a. The sliding tube 4 has a stepped portion 4b formed on the inner periphery in front of the sliding tube collar 4a, and a detection plate formed of a magnetic material of iron or other metal is provided between the stepped portion 4b and the cap 6. A second spring 8 is fitted between the detecting plate 7 and the inner surface of the cap 6, so that the detecting plate 7 is always urged rearward.

The effects of the above-mentioned embodiments will be explained below. The first article with a small thickness D ₁ is now at the detection position P
Assuming that W ₁ (see FIG. 2) exists, the moving device (cylinder) 3 is extended to move the proximity switch 1, that is, the detector S, forward. Then,
First, the article contacting surface 6a comes into contact with the surface of the first article _W1 , and as the proximity switch 1 moves forward, the first spring 5 first contracts and the sliding tube 4 retreats. As the moving device 3 extends over its entire stroke, the detection plate 7 finally comes into contact with the tip flange 1c, and both the first spring 5 and the second spring 8 are further compressed a little. At this time, the detection plate 7 approaches the operating portion 1a of the proximity switch 1, and since this approach falls within the detection range of the proximity switch 1, the proximity switch 1 outputs a detection signal. (Situation shown in Figure 2). In addition, in the case of the second article W ₂ with a slightly larger thickness D ₂ ,
As shown in FIG. 3, the first spring 5 and the second spring 8 are almost fully compressed due to the full stroke of the moving device 3, and the proximity switch 1 outputs a detection signal as described above. In other words, in this embodiment, a detection signal can be generated without any problem if the dimensional difference between the articles is within the range of the thickness difference (D ₂ - D ₁ ) between the first article W ₁ and the second article W ₂ . It's watery.

Note that FIGS. 4 and 5 show the case where press works W ₃ and W ₄ are arranged as detection articles instead of the first and second articles W ₁ and W ₂ shown in FIGS. 2 and 3. It shows. The detector S in this case is the same as in the previous embodiment. Illustrated thickness difference D
corresponds to the difference in thickness D ₂ −D ₁ .

In addition to the above-mentioned embodiments, this invention can also be modified as described below.

(a) The proximity switch may be of a type other than the electromagnetic type shown in the above embodiment.

(b) The moving device 3 may be a linear actuator other than a cylinder.

(c) The detection plate 7 may be made of a magnetic material other than iron-based metals, such as nickel.

(d) First spring 5 and second spring 8
may be a spring having a shape other than that shown.

(Effects of the invention) In this invention, a sliding cylinder is supported by a proximity switch so as to be movable back and forth, an article contacting surface that can come into contact with an article is provided at the tip of this sliding cylinder, and this sliding cylinder is supported by a spring. A detection plate which is biased forward by a spring and which outputs an output signal in close proximity to the proximity switch is fitted inside this sliding cylinder so that it can be slid and is biased backward by a spring. Since the formed detector is moved forward and backward relative to the object to be detected by a moving device, when the object contacting surface abuts the object, even if the object has a large or small thickness, Not only can the difference in thickness be absorbed by the stroke of the spring, but also the detection plate is brought close to the proximity switch at a certain distance by the spring, so that stable object detection is possible at all times. Furthermore, the structure is simple and the operation is easy.

[Brief explanation of the drawing]

Each of the drawings is a central vertical sectional view of an embodiment of the invention, with FIG. 1 showing the detector in an inoperative state, and FIGS. 2 to 5 showing objects detected by the detector. indicates the operating state. DESCRIPTION OF SYMBOLS 1...Proximity switch, 1a...Proximity switch operating part, 1b...Spring receiving collar, 1c...Tip part collar, 2...Gripping means, 3...Moving device (cylinder), 4...Sliding tube, 4a...Sliding tube collar,
4b... Step portion, 5... First spring, 6... Cap, 6a... Article contact surface, 7... Detection plate, 8
...Second spring, W ₁ ...First article, W ₂ ...
...Second article, S...detector.

Claims (1)

[Scope of utility model registration request] An article detection device comprising a detector for detecting the presence or absence of an article and a moving device for moving the detector forward and backward to a detection position where the article is set, wherein the detector is moved forward and backward by the moving device. a proximity switch, a sliding tube supported so as to be movable back and forth concentrically with the proximity switch, and further having an article abutting surface whose front end comes into contact with the article; and a sliding tube that is always urged forward. a first spring, which is movably disposed within the sliding tube, and which is detected by the proximity switch when the sliding tube slides rearward; An article detection device comprising: a second spring that is biased and compressed according to the thickness of the article when the thickness of the article is non-uniform.