Electricity: circuit makers and breakers – Electric switch details – Actuators
Reexamination Certificate
2002-01-08
2003-09-02
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Electric switch details
Actuators
Reexamination Certificate
active
06613996
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a low-noise key switch, and more particularly, to a key switch with an elastic element to absorb impact induced in the operation of the key switch.
2. Description of the Prior Art
As the technology and the information system continuously progress, computers become indispensable to daily activities. Keyboard is commonly utilized in different kinds of equipment, including computers, as input device.
A keyboard typically includes a base. A plurality of key switches are disposed on the base. Each key switch generally includes a key cap supporting by a resilient member, such that the key switch performs a movement relative to the base. The key cap, when struck by user, moves toward the base. The resilient member, responsive to the movement of key cap, is deformed to activate a corresponding circuit. Therefore, a signal is generated to accomplish the input operation.
In general, a supporter is disposed under the key cap to uniformly distribute a downward pushing force applied to the cap. Particularly, when the reduction of height of a keyboard for portable equipment, such as notebook computer, is extremely demanding, a scissor-like supporter is commonly used to serve the purpose.
However, when the key cap is moved vertically relative to the base, noises tend to be produced due to impact of the key cap toward the base. In pursuit of a low-noise working environment, it is a desire to provide a key switch and a keyboard diminishing noise during operation.
SUMMARY OF THE INVENTION
The present invention is directed toward a low-noise key switch. The present invention introduces an elastic element to absorb induced impact, when the key switch is activated, leading to the reduction of noise.
In accordance with the present invention, the key switch includes a cap, a supporter, a switch, at least one elastic element, and a base. The switch, disposed on the base, further includes a membrane switch and an actuator. The actuator includes a resilient member disposed on the membrane switch.
The cap has a top surface, an inner bottom surface, and a bottom edge surface. A first connecting portion is disposed on the inner bottom surface of the cap. A second connecting portion is disposed on the base. The supporter has a first end connected to the first connecting portion of the cap and a second end connected to the second connecting portion of the base. Thus, the supporter supports the cap to selectively perform a movement relative to the base. The switch, responsive to the movement of the cap, selectively turns on. In other words, the resilient member is deformed responsive to the movement of the cap and actuates the membrane switch to turn on the switch.
In accordance with a first embodiment, a plurality of the elastic elements is disposed on the bottom edge surface. When the cap moves toward the base, the elastic elements approach the base prior to the cap hits the base. Therefore, impact of the cap toward the base is absorbed by the elastic elements. The key switch of the first embodiment further includes an extra elastic element. The extra elastic element is disposed, corresponding to the bottom edge surface, on the base.
In a second embodiment, a plurality of the elastic elements is disposed on the base corresponding to the bottom edge surface of the cap. When the cap moves toward the base, the cap approaches the elastic elements prior to the cap hits the base. Therefore, impact of the cap toward the base is absorbed by the elastic elements. The key switch of the second embodiment further includes an extra elastic element. The extra elastic element is disposed on the bottom edge surface.
In a third embodiment, a plurality of the elastic elements is disposed on the base corresponding to the bottom edge surface of the cap and the bottom edge surface of the cap, respectively. When the cap moves toward the base, the elastic elements approach each other prior to the cap hits the base. Therefore, impact of the cap toward the base is absorbed by the elastic elements.
The present invention also provides a keyboard including a key switch recited in the first, the second, or the third embodiment.
REFERENCES:
patent: 5247143 (1993-09-01), Suwa
patent: 5950810 (1999-09-01), Pan et al.
patent: 5990435 (1999-11-01), Chao
patent: 6137071 (2000-10-01), Yeh et al.
Friedhofer Michael
Nixon & Peabody LLP
Silitek Corporation
Studebaker Donald R.
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