JPH0679457B2 - Pressure switch for control cable - Google Patents

Description

The present invention relates to a switch attached to a control cable used for remote operation in various industrial equipment such as automobiles.

More specifically, the present invention relates to a pressure switch for a control cable, which has a mechanism for actuating an electric contact according to the operation of the control cable to send an electric signal to a related device.

[Prior Art] Conventionally, as a control cable operation detection switch device, there is a structure in which a switch for detecting the operation of the control cable is incorporated in the control cable as shown in Japanese Utility Model Publication No. 48-13301.

The control cable consists of a flexible inner cable that is slidably inserted in a flexible conduit. By pulling or pulling one of the inner cables, the remote related equipment can be connected. Used to operate. In the control cable having such a structure, particularly when a pulling operation is performed, a force in the compression direction is applied to the conduit, conversely. By utilizing such a phenomenon, a switch is attached in the middle of the conduit divided into two parts, and the electric contact is closed by the movement of the conduit when the inner cable is operated to close the electric current.

[Problems to be Solved by the Invention] By the way, in the conventional device as described above, when pressure is applied to the conduit by the operation of the control cable,
The movable contact that is in contact with the conduit slides and contacts the terminal,
It has a structure that switches on. That is, it is a switch having a structure in which a stroke is detected and a contact is brought into contact with a terminal. For this reason, when mounting the control cable on the related equipment, if the stroke is not adjusted enough, the contact may not close when the control cable is operated to apply more than a predetermined amount of pressure to the related equipment, or vice versa. However, there is a big drawback that the related equipment may be damaged and a malfunction may occur due to the fact that the predetermined pressure is not reached despite the fact.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and an object thereof is to provide a pressure switch for a control cable having a structure in which the pressure applied to the control cable is accurately detected and the contacts are closed.

[Means for Solving the Problems] The pressure switch for a control cable of the present invention comprises:
(A) A casing having a bottom, having an inner cable insertion hole formed near the center of the bottom, and engaging means projecting from the casing; and (b) being housed in the casing and having a central portion. A printed circuit board having an inner cable insertion hole and at least bipolar electrodes printed in an arbitrary pattern; and (c) a disk-shaped printed circuit board having an inner cable insertion hole superposed on the electrode side of the printed circuit board. Pressure sensitive conductive rubber,
(D) A push plate in which one surface contacts the pressure-sensitive conductive rubber and a boss projects from the other surface, and an inner cable insertion hole is formed in the boss; and (e) a push plate projects from the push plate. A through hole is provided for the boss to project through,
And a spacer fitted in the casing so as not to press the push plate, and (f) a region of the maximum diameter portion abuts on the spacer, and the tip of the boss is inside the region of the minimum diameter portion. Takenoko spring that abutted against,
(G) A flange portion that is in contact with the outside of the smallest diameter portion of the bamboo spring and is slidably accommodated in the casing is provided at one end, and the other end has a conduit insertion hole into which a conduit can be inserted and fixed. At the same time, it has a cap member having an inner cable insertion hole formed in the center thereof, and (h) locking means for preventing the respective members including the cap member from coming out of the casing. I am trying.

[Operation] When the inner cable of the control cable is pulled and operated, a reaction force acts on the conduit in the compression direction. Therefore, when the brim of the casing cap attached to the end of the conduit pushes down the abutment bamboo spring that is in contact, the boss that abuts the inside of the bamboo spring is pushed down, and the push plate presses the pressure sensitive ductile rubber. Therefore, the electrodes of the printed circuit board which are in contact with the pressure-sensitive conductive rubber are connected to each other to be energized and an electric signal can be sent to a related device.

[Embodiment] Next, a pressure switch for a control cable of the present invention will be described with reference to the drawings.

1 is a perspective view showing a state before assembly of an embodiment of a pressure switch for a control cable of the present invention, and FIG. 2 is a sectional view showing the assembled state in FIG.

An embodiment of the pressure switch for a control cable of the present invention will be described with reference to FIGS.

(1) is a cylindrical casing having a bottom, and an engaging means (2) is projectingly provided in the bottom portion and an inner cable insertion hole (3) is provided therein. At the bottom of the first storage chamber (1a) provided in the casing (1), for example, a printed circuit board (5) having a pattern as shown in FIG. 1 is provided with electrodes (4a, 4a).
b) is housed toward the opening of the casing (1), a pressure-sensitive conductive rubber (6) is superposed thereon, and a boss (8) is placed on the pressure-sensitive conductive rubber (6). ), The push plate (7) is housed with the boss (8) facing the opening direction of the casing (1).
The second storage chamber (1b) is formed so as not to press the respective members, the spacer (9) is adjacent to the push plate (7), and the spacer (9) is bored. The boss (8) is projected from the through hole (10). Further, a bamboo shoot spring (11) is fitted adjacent to the spacer (9), one region of the maximum diameter part thereof is brought into contact with the spacer (9), and the inside of the one region of the minimum diameter part is the boss ( It is in contact with the tip of 8). A cap member (13) is provided on the outside of the smallest diameter side of the bamboo shoot spring (11).
Is abutted against a collar portion (12) provided at the end of the, and the collar portion (12) is biased in the direction of the arrow A by the bamboo shoot spring (11). It is locked by a snap ring which is a locking means (15) so as not to fall out from the inside of the casing.

The operating state of the control cable pressure switch having the above structure will be described with reference to FIG.
The inner cord (16) exposed from the end of 7) and passing through each inner cord insertion hole (3, 5a, 6a, 7a) in the pressure switch and connected to the lever of the related equipment is in the direction of arrow A. When the pipe is pulled, the reaction force acts on the conduit (17) to compress it in the direction of the arrow B. Such a compressive force tends to move the collar portion (12) provided at the end of the cap member in the direction of the arrow B, but is equal to or more than a certain amount against the urging force of the bamboo shoot spring (11) in the direction of the arrow A. Bamboo spring (11) without pressure
Has a spring constant that is not compressed in the direction of the arrow B. Further, when the inner rope (16) is pulled in the direction of the arrow A and pressure is applied to the bamboo shoot spring (11) by the collar portion (12), the push plate (7) that is in contact with the inside of the bamboo shoot spring (11). ) Boss (8) moves in the direction of the arrow B, and pressure is applied to the pressure-sensitive conductive rubber (6), so that it is energized, and between the electrodes (4a, 4b) printed on the printed circuit board (5). The electric circuit closes and current flows.

That is, unlike the conventional switch, the pressure switch for the control cable of the present invention does not need to take into account the position where the contact is closed by the stroke when the control cable is assembled to the related device, and after the stroke for operating the related device is secured. , The contact can be closed by further applied pressure, so the application is extremely wide,
For example, by using it as a terminal of a control cable for a governor control actuator of a diesel engine in a construction machine, it can be used as a device for preventing overload on the governor.

EFFECTS OF THE INVENTION The pressure switch for control cables of the present invention has a structure in which a fixed pressure is sensed and the electric circuit is closed by a combination of an electrode, a pressure-sensitive conductive rubber, and a bamboo spring. It can be easily assembled to related equipment with almost no relation, and the stroke from the point of detecting the pressure to the closing of the contact is extremely small due to the structure, so the accuracy is very high compared to the conventional one, and further vibration It also has excellent effects that have never been seen, such as being strong against.

[Brief description of drawings]

1 is a perspective view showing a state before assembly of an embodiment of a pressure switch for a control cable of the present invention, and FIG. 2 is a sectional view showing the assembled state in FIG. (Main symbols in the drawings) (1): Casing (2): Engaging means (3): Inner cable insertion hole (4a, 4b): Electrode (5): Printed circuit board (6): Pressure-sensitive conductive rubber (7) ): Push plate (8): Boss (9): Spacer (10): Through hole (11): Bamboo spring (12): Collar part (13): Cap member (14): Conduit insertion hole (15): Engagement Stopping means

Claims (1)

[Claims] 1. A casing which is (a) cylindrical with a bottom, in which an inner cable insertion hole is formed near the center of the bottom, and which is provided with engaging means, and (b) is housed in the casing. A printed circuit board having an inner cord insertion hole in the center portion and at least bipolar electrodes printed in an arbitrary pattern; and (c) overlapping the electrode side of the printed circuit board, and the inner cord insertion hole in the center portion. A disk-shaped pressure-sensitive conductive rubber having: (d) a push plate having one surface abutting on the pressure-sensitive conductive rubber and a boss protruding from the other surface, and an inner cable insertion hole formed in the boss. And (e) a spacer provided with a through hole through which the boss projectingly provided on the push plate protrudes, and fitted into the casing so as not to press the push plate, and (f) the spacer. One of the largest diameter parts on the spacer Area of the bamboo boss and the tip of the boss abut on the inside of one area of the minimum diameter portion, and (g) abuts on the outside of the minimum diameter portion of the bamboo spring and slides into the casing. A cap member having a movably accommodated collar portion at one end and a conduit insertion hole into which the conduit can be inserted and fixed at the other end, and an inner cable insertion hole formed in the center portion, (h) the cap A pressure switch for a control cable, having locking means for preventing the respective members including the members from being separated from the casing.