JPH0822742A - Limit switch - Google Patents

Abstract

PURPOSE:To detect a surface without damaging it, and smoothly absorb an overstroke by smoothly and sunggly contacting a shock absorbing material with a detection object having a soft surface or a detection object having a painted surface. CONSTITUTION:A limit switch 1 is formed as a structure that an actuator 3 displaceable in a straight line is provided on one end of a main body case 2 internally trimmed with a switching mechanism so as to freely protrude and retreat, and a shock absorbing material 4 composed of rubber or a soft synthetic resin material is installed on the tip of the actuator 3 by a machine screw 5. This shock absorbing material 4 is formed in a forward opening hollow bellows-shaped body, and can be easily elastically deformed in all directions by external force. The shock absorbing material 4 is compressively deformed by easily becoming sungg with the surface by contact with a detection object A, and contacts with a surface of the detection object A without damaging it, and can detect the relative approach.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a limit switch used for detecting the operation limit of various mechanical devices.

[0002]

2. Description of the Related Art As the above limit switch, for example, as shown in FIGS. 9 and 10, an actuator 3 for operating an internal switching mechanism is linearly displaced from a main body case 2, and shown in FIG. As described above, the one in which the detection lever 9 is swingably attached to the main body case 2 is often used.

[0003]

In the structure shown in FIG. 9, the object to be detected comes into direct contact with the tip of the actuator 3, so that the object to be detected whose surface is coated or the object made of plastic is detected. In the target object, there is a possibility that minute contact points or fine scratches may be generated.

Further, in the structure shown in FIG. 10, the compression coil spring 13 attached to the tip of the actuator can be tilted and deformed in any direction, and is configured as a non-directional operation type capable of detecting a contact from any direction. However, if the compression coil spring 13 is pressed straight in the axial direction with a large stroke, the actuator 3 may be pressed beyond the operation limit and the internal switching mechanism may be damaged. .

Further, in the swing type shown in FIG. 11, the operation limit position b is set in an ON region having an appropriate angle from the switch ON position a, and it is possible to absorb an overstroke between the ON regions. However, if the dog 12, which is the detection target object, overruns significantly due to an unexpected situation, a trouble such as breakage, deformation, or poor recovery of the detection lever 9 may occur. there were.

The present invention has been made by paying attention to such a situation, and is intended to eliminate the above-mentioned problems by making a simple improvement on a detecting portion such as an actuator and a detecting lever. Is.

[0007]

In order to achieve the above object, the present invention has the following configurations. That is, the limit switch of the invention according to claim 1 is characterized in that a shock absorber made of a soft elastic material is provided at the tip of the actuator that is linearly displaced.

Further, in the limit switch of the invention according to claim 2, a contact body is provided at the tip of the actuator which linearly moves back and forth through a compression coil spring, and the tip contact surface of this contact body is formed into a convex curved surface. It is characterized in that it is configured.

Further, in the limit switch of the invention according to claim 3, a swingable detection lever having a detection roller at its tip is configured to be bendable and deformable in the lever operating direction via an elastic body interposed in the middle thereof. It is characterized by being done.

[0010]

According to the structure of claim 1, the cushioning body made of the soft elastic material is elastically deformed along the surface of the object to be detected without difficulty, and the elastic deformation absorbs the stroke.
It is possible to avoid applying unreasonable load to the interior mechanism.

Further, according to the second aspect of the invention, since the tip contact surface of the contact body is a convex curved surface, it almost comes into point contact with the object to be detected, and this contact point deviates from the actuator operating axis. As a result, an operation component force in the laterally falling direction acts on the compression coil spring, and it is possible to prevent the compression coil spring from falling and deforming and applying an unreasonable load to the internal mechanism.

According to the third aspect of the invention, when an operation force exceeding the operation limit position is applied to the detection roller at the tip of the detection lever, the elastic body in the middle of the lever falls and elastically deforms to absorb the overstroke without difficulty.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1] FIGS. 1 to 4 show an embodiment of the invention according to claim 1.

As shown in FIG. 1, the limit switch 1 has a structure in which an actuator 3 which linearly displaces is provided at one end of a main body case 2 having a switching mechanism incorporated therein so that the actuator 3 can be moved back and forth. A shock absorber 4 made of rubber or a soft synthetic resin material is attached to the screw by a screw 5.

The buffer body 4 is formed in a hollow bellows shape that is open to the front, and can be easily elastically deformed in any direction by an external force, as shown in FIG. 1 (b). By the contact with the detection target object A, the surface thereof is easily adapted and compressed and deformed, and the surface of the detection target object A can be contacted without being damaged and the relative approach can be detected.

FIG. 2 shows a modified example of the above-mentioned cushioning body 4, in which the cushioning body 4 formed in the shape of a hollow bellows whose front is closed by a rubber or soft synthetic resin material is the tip of the actuator 3. It is elastically fitted and fixed to. In this case, a small air hole 5 is formed in order to facilitate the compressive deformation of the buffer body 4. Even in this configuration,
Similar to the previous example, the cushioning body 4 can be easily elastically deformed by an external force in any direction, and when it comes into contact with an object to be detected, it is easily adapted to its surface and compressed and deformed, without damaging the surface of the object to be detected. It is possible to make contact and detect the relative approach.

FIG. 3 shows a further modified example of the buffer body 4, in which the buffer body 4 made of rubber or a soft synthetic resin material and having a hollow spherical shape is inserted into the tip of the actuator 3. It is fixed. Also in this case, small air holes 5 are formed in order to facilitate the deformation of the buffer body 4, and the same function as in the previous example is achieved.

[Embodiment 2] FIG. 5 and FIG.
An embodiment of the invention according to is shown.

As shown in FIG. 5, the limit switch 1 has a structure in which a linearly displacing actuator 3 is provided at one end of a main body case 2 having a switching mechanism incorporated therein so that the actuator 3 can be moved back and forth. A detection body 7 is attached to this via a compression coil spring 6, which is an example of an elastic body, and is configured to be a non-directional movement type.

The detection body 7 is formed of a synthetic resin, rubber, or a metal material in a columnar shape or a spherical shape,
Since the contact surface S at the tip is circular or spherical, it comes into point contact with the object to be detected, and if this contact point deviates even slightly from the operating axis of the actuator, the compression coil spring is operated in the direction of falling sideways. The component force acts to prevent the compression coil spring from falling and deforming and applying an unreasonable load to the internal mechanism.

The detection body 7 may be formed in a semicircular shape or a hemispherical shape as shown in FIG. Further, the tip end contact surface S of the detection body is not necessarily circular or spherical, and may be a smooth convex curved surface. Further, the elastic body attached to the tip of the actuator 3 is not limited to the compression coil spring 6, and it is also possible to use a short-axis rubber.

[Embodiment 3] FIG. 6 and FIG.
An embodiment of the invention according to is shown.

The limit switch 1 has a structure in which a main body case 2 incorporating a switching mechanism is provided with an operation shaft 8, and a base portion of a detection lever 9 is externally fitted and fixed to the operation shaft 8 by tightening. A detection roller 10 is provided at the tip of the detection lever 9, and a compression coil spring 11 as an example of an elastic body is interposed between the levers.

This limit switch 1 includes a detection lever 9
Dog as a detection target attached to a mechanical device
The switch-on position is located at a position where the detection lever 9 is pressed and oscillated to the set angle, and the operation limit position b is set with the ON region of the set angle.

Therefore, as shown in FIG.
Even when is operated beyond the operation limit position b, the compression coil spring 11 is tilted and deformed, so that an overstroke with a large dog can be naturally absorbed.

In place of the compression coil spring 11, a leaf spring or an elastic body made of rubber or the like may be used.

[0028]

As is apparent from the above description, according to the limit switch of the invention according to claim 1 of the present invention, the cushioning material is applied to a detection target object such as plastic having a soft surface or a detection target object whose surface is coated. It is possible to detect it without scratching the surface by touching it comfortably and to absorb overstroke without difficulty.

According to the limit switch of the second aspect of the invention, even if the object to be detected comes into contact with the actuator from the axial direction of the actuator, the contact point with the contact body is displaced and the elastic body is easily collapsed and deformed. As a result, overstroke can be easily absorbed and damage to the internal mechanism can be avoided.

According to the limit switch of the third aspect of the invention, even if an operation exceeding the limit acts on the detection lever, it can be easily absorbed by elastic deformation at the intermediate portion of the detection lever, and the detection can be performed. It is now possible to easily avoid damage to the lever and internal mechanism, and failure to return to the detection lever.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing a limit switch according to a first embodiment.

FIG. 2 is a side view of a main part showing a detection operation state.

FIG. 3 is a partially cutaway side view showing a limit switch including a buffer body according to a modification.

FIG. 4 is a partially cutaway side view showing a limit switch including a buffer body according to another modification.

FIG. 5 is a partially cutaway side view showing a limit switch according to a second embodiment.

FIG. 6 is a side view showing a limit switch having a contact body of a modified example.

FIG. 7 is a side view showing a limit switch according to a third embodiment.

FIG. 8 is a side view showing a detection operation state.

FIG. 9 is a side view showing a conventional limit switch.

FIG. 10 is a side view showing a conventional limit switch.

FIG. 11 is a side view showing a conventional limit switch.

[Explanation of reference numerals] 2 main body case 3 actuator 4 cushioning body 6 elastic body (compression coil spring) 7 contact body 9 detection lever 10 detection roller 11 elastic body (compression coil spring)

Claims (3)

[Claims] 1. A limit switch, characterized in that a shock absorber made of a soft elastic material is provided at the tip of an actuator that linearly moves forward and backward. 2. A contact body is provided at the tip of an actuator that linearly moves back and forth through an elastic body that can be laterally tilted and deformed in all directions, and the tip contact surface of this contact body is formed into a convex curved surface. A limit switch characterized by the fact that there is. 3. A limit switch, characterized in that a swingable detection lever having a detection roller at its tip is configured to be bendable and deformable in the lever operating direction via an elastic body interposed therebetween.