US 4,529,849 AGranted

Push-button switch and a keyboard comprising the same

AssigneeFujitsu Limited

InventorsSeisuke Kamei, Toshiaki Tanaka, Kazutoshi Hayashi, Akira Tanaka, Ryohei Kinoshita

Life of this patent

Estimating the term…

Loading patent…

Abstract

A novel stroke converting mechanism for a push-button switch is disclosed. The stroke converting mechanism is for providing a push-button switch or a keyboard comprising the push-button switches with features such as low cost, low profile, and light and comfortable key touch. The stroke converting mechanism is made from a plate of metal such as 18-8 stainless steel, and fabricated by a single shot of press or by an etching of the plate in a batch process. The delineated plate is then shaped into a specified form by die press. In spite of the simple structure, the stroke converting mechanism can provide a sufficient stroke conversion ratio, e.g., about 4 mm of the key top to a displacement of about 1 mm necessary for actuating a couple of make-break contacts. And also, it reduces the necessary depression force on the key top to a half of the force required for actuating a make-break contacts, and provides a reduction in the height of a push-button switch or a keyboard as much as 3 mm or more.

Claims21

Dependent claims

A push-button switch comprising:

a housing having a guiding hole;
a slider movably installed in the guiding hole of said housing and equipped with a key top, said slider having a bottom face;
a couple of make-break contacts;
and
a stroke converting mechanism for converting a given stroke length of the key top to a desired amount of displacement necessary for actuating said make-break contacts, wherein said stroke converting mechanism comprises a plate spring constituting a unified structure and having:
a first arm whose tip contacts the bottom face of the slider;
a second arm whose tip is located adjacent to the make-break contacts;
a first bend joining said first and second arms at respective ends thereof so that said first and second arms extend toward the same side of said first bend;
a frame for securing said stroke converting mechanism to said housing;
and
two second bends situated along respective sides of said first bend, a first end of each said second bend being combined with said tip of said second arm, and the other end of each said second bend being combined with said frame,
wherein, upon the depression of the key top by an external pressure, said first arm and said second arm move pivotally around said bends from respective initial postions, and said tip of said second arm depresses said make-break contacts to cause them to take the make position, while upon removal of the external pressure to the key top, said first arm and said second arm move pivotally in the counter direction to restore the initial positions of said first and second arms, and said tip of said second arm frees said make-break contacts to cause them to take the break position.

9 more elements

A keyboard comprising:

a case for accommodating elements constituting said keyboard;
a plurality of sets of make-break contacts within said case and disposed on the inner surfaces of two insulating sheets stacked on each other with a spacer in between said two insulating sheets, so that said make-break contacts of each said set face each other with a specified gap, the upper one of said insulating sheets being flexible, and said spacer having apertures at each position corresponding to each said set of said make-break contacts;
a plurality of push-button switches arranged in an array at the top of said case, each including:
a housing having a guiding hole;
a slider movably installed in said guiding hole of said housing and equipped with a key top, said slider having a bottom face;
and
a stroke converting mechanism for converting a given stroke length of said key top to a desired amount of displacement for actuating the respective make-break contacts, wherein said stroke converting mechanism comprises a plate spring constituting a unified structure and having:
a first arm whose tip contacts the bottom face of said slider of the corresponding push-button switch;
a second arm whose tip is located adjacent to the corresponding set of said make-break contacts;
a first bend joining said first and second arms to each other so that said first and second arms extend toward the same side of said first bend;
a frame for securing said stroke converting mechanism to said housing;
two second bends each of which is situated along a respective side of said first bend, wherein one end of each of said second bends is connected with said tip of said second arm, and each other end of each said second bend is connected with said frame;
wherein, upon the depression of each said key top by an external pressure, the corresponding first arm and second arm move pivotally around the respective first and second bends, from respective initial positions, and said tip of the respective second arm depresses a corresponding one of the respective set of make-break contacts to cause them to take the make position, and, upon removal of the external pressure, the respective first and second arms move pivotally in the counter direction to restore their respective initial positions, and said tip of the respective second arm becomes free of the corresponding set of make-break contacts to cause them to take the break position.

10 more elements

Dependencies are inferred from the claim text.