Typewriting machines – Key-board or key lever-actuating mechanism – Key-cap or key-stem structure
Reexamination Certificate
1999-02-19
2001-05-01
Hilten, John S. (Department: 2854)
Typewriting machines
Key-board or key lever-actuating mechanism
Key-cap or key-stem structure
C400S490000, C200S345000, C200S514000, C156S325000, C156S277000
Reexamination Certificate
active
06224278
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present inventions relates to a beautiful and quality key pad to be used for portable phone, portable information terminal, remote control for various home electric apparatuses, card remote control or various keyboards.
2. Related Art
Silicon rubber or the like has been conventionally used as a member for a conventional key pad, because of their excellent low temperature resistance, heat resistance, weather resistance, precise formability and electric insulation. As a key top, soft rubber has been used for disposing graphics composed of character, number, symbol or picture on its surface or light masking portion has been arranged to dispose graphics formed by cutting out a character, number, symbol or picture.
However, as silicone base coating has been used, in every case, as material of graphics to be formed on theses surfaces, they are worn or broken by finger pressure or friction with clothing resulting in the deterioration of visual recognition or appearance.
Therefore, Japanese Utility Model Laid-Open Shouwa 48-15161, Japanese Patent Publication Heisei 7-095411 or Japanese Patent 2627692 have proposed a method wherein a key top part is formed separately with rigid resin for printing its surface or back or elsewhere and then integrated by engaging with a silicone key pad or adhering with adhesive or both faces adhesive tape or the like.
SUMMARY OF THE INVENTION
However, as silicone rubber is less adhesive, silicone base adhesives has been used generally for adhering them. Silicone base adhesives include additional reaction type and condensation reaction type and, relatively high strength silicone adhesives are of condensation reaction type.
On the other hand, adhesives of condensation reaction type take several hours to several days for hardening, lowering their productivity; if a higher productivity is required, it has been necessary to use those of additional reaction type having faster reaction.
However, silicone base adhesives of additional reaction type are less adhesive with resin or printing ink or other organic compound used for a key top, peeling easily after the adhesion. It has been necessary in practice to arrange a collar or the like on the key top part in order to avoid their detachment.
Moreover, the adhesion portion can be treated with primer, but is increases the number of process, resulting in low productivity. On the other hand, Japanese Patent 2627692 does not describe clearly these points.
The Present Invention relates to a keypad with rigid resin key top, solving these problems.
The key pad with rigid resin key top of the present Invention is a method for manufacturing a key pad with rigid resin key top comprising steps of preparing urethane base adhesive substrate on the back face of a key top made of rigid resin and for adhering with a silicone rubber made key pad, by enhancing the adhesive strength of silicone base adhesives to be used, characterized by that the key top does not detach nor dislocated, allowing to omit collar or other means for preventing key detachment and to simplify its structure.
REFERENCES:
patent: 5888656 (1999-03-01), Suzuki et al.
patent: 6084190 (2000-07-01), Kenmochi
patent: 48-15161 (1946-07-01), None
patent: 7-95411 (1995-10-01), None
patent: 2627692 (1997-07-01), None
Grohusky Leslie J.
Hilten John S.
McGlew & Tuttle P.C.
Polymatech Co. Ltd.
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