Electricity: circuit makers and breakers – Electric switch details – Latches
Reexamination Certificate
2000-10-02
2001-12-25
Luebke, Renee (Department: 2832)
Electricity: circuit makers and breakers
Electric switch details
Latches
C200S523000
Reexamination Certificate
active
06333476
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a push-button switch used for operating a crane or a hoist, more specifically a push-button switch realized in such a way that the push button can be held lightly at the current position when the push button of the push-button switch is pressed down.
PRIOR ART
As push-button switch provided with a clip mechanism for temporarily fastening the push button at the current position when the switch is pressed down, a type as shown in
FIG. 10
, has so far been widely used, for example.
This push-button switch is realized by disposing steel balls
29
urged by a spring for steel ball
28
on a push button
27
, and forming a stepped part for clip
31
in a way to face the steel balls
29
along the wall face of the switch body
30
on which the push button
27
slides, so as to clip the push button
27
at prescribed pressed down position by fastening the steel balls
29
to this stepped part for clip
31
when the push button
27
is pressed down.
By the way, a push-button switch used for operating a crane or a hoist allows the crane, etc. to work while the switch operation is made for a fairly long time when making a travelling motion. On this type of push-button switch is disposed a return spring for urging the push button in the direction opposite to the direction of the pressing down operation, to make the push button return to its initial position when the pressing down operation is released and, usually, a spring having a comparatively large spring constant is used as return spring, so that the push button may return accurately even when dust, etc. is bitten there.
For that reason, the holding pressure of the push button inevitably increases, and said conventional type of push button had a problem of poor operability such as fatigue of the finger pressing the push button in the case of a long operating time.
SUMMARY OF THE INVENTION
The objective of the present invention is to provide, in view of the problem of said conventional type of push buttons, a push-button switch realized in a way to be held lightly with small force at the position where the push button is pressed, and obtain a large returning force when the pressing force of the push button is released.
To achieve said object, the push-button switch according to the present invention is realized as a push-button switch slidably disposing the push button on the switch body and urging it along with a return spring, characterized in that it comprises a hole formed in the push button in its pressing direction, a spring for balls inserted in said hole, a window opening on the side face of the push button in communication with the bottom of the hole, a ball for temporarily fastening disposed at said window, a concavity, formed along the wall face on the switch body side on which the push button slides, in which to fit part of the ball for temporary fastening at the position where the push button is pressed, and an auxiliary push button, disposed at the top of the push button in a way to be pressed, by being urged by said spring for ball, for pressing the ball for temporary fastening to the outside through the spring for ball while pressing, to fit part of the pushed out ball for temporary fastening in the concavity formed along the wall face on the switch body side.
This push-button switch presses the ball for temporary fastening to the outside through the spring for ball with the pressing made simultaneously with the pressing of the auxiliary push button.
With this operation, part of the pushed out ball for temporary fastening is made to fit in the concavity formed along the wall face of the switch body side, and the push button is temporarily fixed at the current position by the resisting force produced by the fitting of this ball for temporary fastening in the concavity, making it possible to lightly hold the push button pressed against the return spring with a small force.
Moreover, when releasing the pressing force on the push button, the pressing force pushing the ball for temporary fastening to the outside diminishes.
As a result, the fitting of the ball for temporary fastening in the concavity formed along the wall face on the switch body side is disengaged, and the urging force of the return spring acts directly on the push button, thus obtaining a large return force.
This makes it possible to provide a highly safe push-button switch with excellent operability, reducing the burden on the operating worker.
In this case, it is possible to form a concavity in which to fit part of the ball for temporary fastening at the position where the push button is returned, along the wall face on the switch body side on which the push button slides.
With this arrangement, part of the ball for temporary fastening is subject to a resisting force by being fit in the concavity formed at the position where the push button returns to at the start of the pressing of the auxiliary push button, and the push button is pressed at a stroke after accumulating a force until this ball for temporary fastening retreats and gets away from the concavity against the spring for ball. As a result, the contact of the switch body can be instantly connected.
This helps improve the durability of the equipment by reducing electric exhaustion of the contact, and by preventing occurrence of troubles such as burning of motors, etc., especially with the improvement of operability of push-button switches with
2
a
contacts requiring opening and closing of 2 contacts without any time lag.
REFERENCES:
patent: 5272383 (1993-12-01), Umemura
patent: 5576525 (1996-11-01), Umemura
patent: 5932854 (1999-08-01), Umemura
patent: 5965854 (1999-10-01), Umemera
patent: 5994652 (1999-11-01), Umemera
patent: 64615 (1982-04-01), None
Luebke Renee
Nguyen Nhung
Shinkoh Electric Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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