JPH07302395A - Contact sensor - Google Patents

Abstract

PURPOSE:To prevent the generation of short-circuit between contacts by holding the inner pressure of an internal closed space at the same pressure as atmospheric pressure. CONSTITUTION:This contact sensor including a sensor body constituted of including a pair of upper and lower electrode plates 13, 14 opposed to each other through a fine gap in a flat space formed in a flat plate-like body consisting of an elastic material such as rubber and synthetic resin and mutually abutting and short-circuiting the plates 13, 14 by pressing force from the upper and lower parts of the flat plate-like body is provided with a small diameter communication hole making the flat space of the plate-like communicate with the body atmosphere. A cabtyre cable 32 consisting of the bundle of plural lead wires is loosely inserted into a nipple-like cabtyre cable inserting hole perforated into the flat plate-like body with proper gaps and a small diameter hole is vertically pierced through the cable to form the small diameter communication hole.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to contact sensors.

[0002]

2. Description of the Related Art As a sensor for detecting the presence of a target object, a sensor with a built-in contact has been known, which utilizes short-circuiting of the contact due to the weight or contact of the object.
As shown in the perspective view of FIG. 7 and the cross-sectional view of FIG.
In some cases, the sensor main body 71 has a structure in which it is completely sealed with rubber or the like in order to prevent dust and moisture depending on the situation such as the installation location. A lead wire 72 for extracting an output signal extends from the sensor main body 71, and 81 is a flat rectangular flexible case that is formed of an elastic body such as rubber or synthetic resin and that hermetically surrounds the sensor main body 71. In the internal space 84, a pair of electrode plates 82 and 83 are mounted so as to face each other vertically. As shown in the vertical cross-sectional view of FIG. 9, the structure of the built-in contact is completely covered with an elastic body such as rubber or synthetic resin of the same kind including both ends of the case 81, and the internal space 84 is sealed. There is. The pair of external lead wires 72 are connected to the internal lead wires 96 and 97 by crimping terminals or the like via the connecting portions 94 and 95, respectively.
Directly joined to the pair of electrode plates 82 and 83,
Reference numerals 92 and 93 are the joints. The contact sensor 71 of this type is directly attached to a place where an object is actually detected, and when an object (not shown) passes over the case 81 or directly contacts the sensor body 71, the weight of the object is reduced. The presence or absence of contact with the target object is detected by pressing or pressing.
At that time, when an object comes into contact, the case 81 of the sensor body 71 is deformed by the pressing, and the electrode plates 82 and 83 are short-circuited, so that a current flows through the lead wire and the contact with the object is detected. .

A contact sensor of this type is shown in FIG.
As shown in, it is used for a vehicle detection device, a vehicle type identification device, etc. of a toll collection system on a toll road or a parking lot. In the figure, reference numeral 101 denotes a passing vehicle, which advances in a vehicle approach path 102 in the direction of arrow A. Reference numeral 103 denotes a vehicle detection device, which is provided with the vehicle separators 104 and 105 that are installed to face each other with the vehicle entrance 012 interposed therebetween.
4, 105 and the tread 106 embedded in the road surface below the optical axis. Here, as shown in FIGS. 11 to 12, 111 is a tread body, which is made of an elastic material such as rubber. The tread body 111 has four cavities 121 a, 1 a.
21b, 121c, 121d are provided, and contact type sensors are mounted in these cavities. Reference numeral 122 is a substrate that supports the contact sensor and has a rigid structure. Therefore, the contact sensor built in the tread 111 is completely sealed, and the vehicle detection device detects the vehicle based on the output signals from the vehicle separators 104 and 105 and the tread 106 described above.

[0004]

As described above, in the conventional contact sensor of this type, the inner space is completely sealed by the elastic body such as rubber, and the sealed space volume is very small. Therefore, air (oxygen) in the internal closed space was physically or chemically absorbed by a substance such as rubber, which is the inner wall, or used at a place where the object was continuously pressed. In this case, a sudden change in atmospheric pressure (increase) in the space inside the sensor occurs continuously, so that a phenomenon occurs in which air permeates an elastic body such as rubber and leaks to the outside of the space. As a result, the internal pressure of the contact sensor is reduced to a negative pressure compared to the atmospheric pressure, which may cause the contacts to be short-circuited.

The present invention has been proposed in view of such circumstances, and the internal pressure of the internal space is always kept the same as the atmospheric pressure to prevent the short circuit of the built-in contacts. The structure is simple, the price is low, the operation is reliable, and It is an object of the present invention to provide a weather resistant contact sensor having a long life and high reliability.

[0006]

Therefore, the first aspect of the present invention is
A flat space formed inside an elastic material such as rubber or synthetic resin has a flat space inside which a pair of upper and lower electrode plates facing each other with a small clearance is built in. In a contact sensor having a built-in sensor body for contacting and short-circuiting the electrode plates by a pressing force from, a small-diameter communication hole for communicating the flat space of the flat plate-like body with the atmosphere is characterized. And

According to a second aspect of the invention, in the first aspect, the cabtire cable formed by bundling a plurality of lead wires connected to both electrode plates as the small diameter communication hole is formed on the flat plate-like body. It is characterized in that the cabtyre cable insertion hole of the nipple-like protruding portion is loosely inserted with an appropriate gap.

According to a third aspect of the present invention, in the first aspect, a cabtyre cable having a plurality of lead wires connected to both electrode plates and having a longitudinal small diameter hole in the center is provided. Characterize.

[0009]

With this structure, the pressure in the internal space of the internal contact can always be kept the same as the atmospheric pressure. As the communication means, the insertion hole of the lead wire for taking out the output signal to the outside is used as the ventilation pipe, so that the internal pressure of the internal space of the sensor can be kept the same as the atmospheric pressure in the portion apart from the sensor body. In addition, the performance of the sensor itself is not impaired, there is no need to add additional parts (ventilation pipes, etc.), and the conventional maintainability (installation and removal) can be maintained. Therefore, it is possible to prevent a decrease in the internal pressure of the internal space of the sensor while maintaining the function, size, and mountability of the sensor as they are, and to prevent a short circuit of the contact caused by this.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment in which the present invention is applied to a tread plate of a vehicle detection device will be described. FIG. 1 is a partial vertical sectional view showing an output end portion of the embodiment of the present invention, and FIG. FIG. 3 is an enlarged view showing the II part, FIG. 3 is an overall perspective view showing the sensor body of FIG. 1, FIG. 4 is an overall external perspective view of FIG. 1, FIG. 5 is a vertical sectional view showing the output end of FIG. 4, and FIG. VI-VI showing the lead wire of FIG.
FIG.

First, in FIG. 1 to FIG. 3, 31 is a sensor outer case, 32 is a cabtire cable extending from the sensor outer case 31, the output signal from the outer case 31 is transmitted to the inside of the cable 32, and the inside thereof. A lead wire (not shown) that communicates the space with the atmosphere is buried. This external case 31 has no particular difference in appearance from the conventional contact sensor.

The end structure of the outer case 31 will be described. As shown in FIG. 1, reference numeral 11 denotes an elastic body such as rubber or synthetic resin forming the sensor main body 31.
Electrode plates 13 and 14 (FIG. 1) are attached to 2 along the upper and lower surfaces thereof so as to face each other with a small gap. Lead wire 16,
Reference numeral 17 is connected to the internal lead wires 21 and 22 via crimp terminals 15 respectively.
Are directly bonded to the electrode plates 13 and 14 via the bonding portions 18 and 19, respectively. The above is the same structure as the conventional contact sensor shown in FIG. 9, but in the present invention, in this conventional structure, the air in the internal space 12 is communicated with the atmosphere by using the lead wire as shown in FIG. It has a structure.

4 to 5, 41 is a tread body, 42 is a tread upper part, 43 is a sensor part, 44 is a cable, and the base end of the cable 44 is a tread sensor part 43.
May extend through the nipple-shaped protrusion 45 formed integrally with the outside, and the tip end thereof may be sealed against the atmosphere. This tread plate has no difference in appearance from the conventional tread plate, and has a structure in which the lead wire is branched into four contact points in the upper tread plate 42 and connected to the internal space of each sensor body. FIG. 5 shows a vertical cross-sectional view of the tread upper part 42, that is, a joint between the cable 44, the connecting fitting 57 and the sensor inner space 12, 51 is an inner cavity of the tread body 41, and the sensor body 52 is inserted into the inner cavity 51. The inner space 12 of the sensor body 52, which is attached to the inner space of the sensor body 52, is closely spaced. In addition, the electrode plate 54 is vertically opposed to the inner wall of the internal space 12.
a, 54b are attached, and lead wires 55a, 55b are directly connected to the electrode plates 54a, 54b.
b is the connecting part. Reference numeral 57 denotes a connection fitting, which is connected to the internal space 12 and allows air in the internal space to freely flow in and out. Here, the base end portion of the cable is loosely inserted through the nipple-shaped protruding portion provided on the tread plate with a clearance. Or, provide a small vertical hole in the cable. The outer end of the small vertical hole may be in communication with the atmosphere or may be hermetically sealed. Even in the sealed structure, the increase in volume of the sealed air in the internal space and the vertical small-diameter holes shown in FIG. 5 prevents malfunction of the electrode plate due to generation of negative pressure in the internal space. As shown in the cross-sectional view of FIG. 6, the tread cable 44 includes lead wires 61a, 61b, 62a, 62b, 63a from the respective sensors,
63b, 64a, 64b, the tread main body 41,
Since four sensor bodies are attached and two lead wires are connected to the pair of upper and lower electrode plates for each sensor, there are a total of eight lead wires in the tread cable 44. To do. Each lead wire is divided into 4 for each sensor, 2 for each sensor.
Connected to 2.

The tread sensor section 43 of the above embodiment is shown in FIG.
The tread plate used in the vehicle type identification device shown in FIG. 0 has a contact sensor with higher accuracy than the conventional tread plate used in the vehicle detection device. Therefore, the application of the present invention to the vehicle type identification device can be performed similarly to the vehicle detection device.

[0015]

As described above, in the conventional hermetic contact sensor, there is a possibility of contact short circuit due to internal pressure decrease due to oxygen absorption and gas permeation in the sensor internal space. In addition, the oxygen absorption and gas permeation tend to increase in proportion to the internal pressure, and since the internal pressure rises frequently in a frequently used sealed contact sensor, the oxygen absorption and gas permeation increase and the short-circuit problem does not occur. It was even more serious. However, the contact sensor according to the present invention utilizes the vertical small-diameter communication hole of the cabtyre cable, the axial clearance between the cabtyre cable and the nipple-like protrusion, etc. without impairing the conventional contact sensor function and performance. As a result, the rise in internal pressure can be suppressed, oxygen absorption and gas permeation can be reduced, the internal pressure of the sensor can be kept at atmospheric pressure, and the air volume can be kept constant. is there.

In summary, according to the invention of claim 1, rubber,
A flat space formed in the flat plate-shaped body made of an elastic material such as a synthetic resin is provided with a pair of upper and lower electrode plates facing each other with a small clearance in between, and In a contact sensor having a built-in sensor main body for contacting and short-circuiting the electrode plates by pressing force, a small-diameter communication hole for communicating the flat space of the flat plate-like body with the atmosphere is provided. The present invention is extremely industrially applicable, since the internal pressure of is always kept the same as the atmospheric pressure to prevent a short circuit of the built-in contact, and a weather resistant contact sensor with simple structure, low cost, reliable operation, long life and high reliability is obtained. It is useful.

According to a second aspect of the present invention, in the first aspect, the cabtire cable formed by bundling a plurality of lead wires connected to both electrode plates as the small diameter communication hole is formed in the flat plate-shaped body. The sensor main body having the cabtire cord in the internal space of the flat plate-shaped body to be molded, in addition to the effect according to claim 1, by loosely inserting the cabtyre cable insertion hole of the nipple-shaped protruding portion with a proper gap. The present invention is extremely useful industrially because even a contact sensor having a built-in can prevent negative pressure from being generated in the internal space.

According to a third aspect of the present invention, in the first aspect, the cabtyre cable is formed by bundling a plurality of lead wires connected to both electrode plates and having a longitudinal small diameter hole at the center. In addition to the effect according to claim 1, also in a contact sensor in which a sensor body formed by integrally molding a cabtire cord is built in the inner space of a flat plate-shaped body to be molded, the inner space of the sensor body The present invention is extremely useful in industry because it can prevent negative pressure from being generated.

[Brief description of drawings]

FIG. 1 is a partial vertical cross-sectional view showing an output end portion of an embodiment in which the present invention is applied to a tread plate of a vehicle detection device.

FIG. 2 is an enlarged view showing a portion II of FIG.

3 is an overall perspective view showing the sensor main body of FIG. 1. FIG.

FIG. 4 is a perspective view of the entire appearance of FIG.

5 is a vertical sectional view showing an output end portion of FIG. 4. FIG.

6 is a cross-sectional view taken along the line VI-VI showing the cable of FIG.

FIG. 7 is an external perspective view showing a conventional contact sensor.

8 is a cross-sectional view of FIG.

9 is a horizontal and vertical cross-sectional view of the output end of FIG.

FIG. 10 is a perspective view showing a vehicle detection device.

11 is an external perspective view showing the tread plate of FIG.

12 is a cross-sectional view of FIG.

[Explanation of symbols]

11 Elastic body such as rubber 12 Internal space 13 Upper electrode plate 14 Lower electrode plate 15 Connection fitting (crimp terminal) 16,17 Lead wire 18,19 Joint portion 21,22 Internal lead wire 31 Sensor case 32 Cable (cabtyre cable) 41 tread body 42 tread upper part 43 tread sensor section 44 tread cable 45 nipple-like protrusion 51 tread internal cavity 52 sensor body 54a, 54b electrode plates 55a, 55b lead wires 56a, 56b joint 57 connecting fittings 61a, 61b, 62a, 62b , 63a, 63b, 64a, 64b Lead wire

Front page continuation (72) Inventor Satani Osamu 1-1-1, Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Heavy Industries Ltd. Kobe Shipyard (72) Inventor Takashige Matsuda Wadazaki, Hyogo-ku, Kobe-shi, Hyogo 1-1-1 Machi Mitsubishi Heavy Industries, Ltd. Kobe Shipyard

Claims (3)

[Claims] 1. A pair of upper and lower electrode plates facing each other with a small clearance in a flat space formed inside a flat plate-like body made of an elastic material such as rubber or synthetic resin. In a contact sensor having a built-in sensor main body for contacting and short-circuiting the electrode plates by pressing force from above and below the flat plate-shaped body, a small-diameter communication hole for communicating the flat space of the flat plate-shaped body with the atmosphere is formed. A contact sensor characterized by having. 2. A cabtire cable having a nipple-like protruding portion formed on the flat plate-like body as defined in claim 1, wherein a cabtire cable formed by bundling a plurality of lead wires connected to both electrode plates as the small-diameter communication holes. A contact sensor that is loosely inserted with an appropriate clearance in the cable insertion hole. 3. A contact sensor according to claim 1, further comprising a cabtire cable which is formed by bundling a plurality of lead wires connected to both electrode plates and has a longitudinal small diameter hole in a central portion thereof.