The present invention relates to a button structure for a handy radio apparatus or similar electronic apparatus and more particularly to a button structure for an electronic apparatus including buttons each facing a particular switch device arranged on a printed circuit board with the intermediary of a respective Belleville spring which snaps through when pressed.
A conventional button structure for the above application includes key top members exposed to the outside of the casing of an electronic apparatus, so that the operator of the apparatus can directly touch the key top members. Button bodies are formed on a flat base disposed in the casing. The key top members and button bodies are so arranged as to face switch devices formed on a printed circuit board in the form of a wiring pattern with the intermediary of conductive Belleville springs.
The above conventional button structure has the following problems (1) through (4) left unsolved.
(1) An annoying click sound is produced in proportion to a pressure exerted on each key top member for turning on the associated switch device, i.e., repulsive energy resulting from the snap-through of the associated Belleville spring. Particularly, the click sound is undesirable when it comes to handy radio apparatuses or similar precision apparatuses.
(2) A long stroke is required of each key top member and obstructs easy operation.
(3) The key top members are adhered to the base. Therefore, when even one of the key top members is found defective by the last appearance test, all the key top members mounted on the base must be replaced together with the base. This reduces the yield of production and effects the cost. Particularly, at least the exposed portion of the key top members must be painted and printed in multiple colors, and a great number of steps are necessary for the key top members and base to be assembled and adhered together, aggravating losses ascribable to defective appearance.
(4) Because the key top members and base are formed of different materials, they are not separable or recyclable.
Technologies relating to the present invention are disclosed in, e.g., Japanese Patent Laid-Open Publication Nos. 10-188722, 6-275169 and 8-227632 and Japanese Patent No. 2,741,373.
It is therefore an object of the present invention to provide a button structure for an electronic apparatus capable of reducing the click sound and minimizing the required pressing stroke to thereby promote easy operation.
It is another object of the present invention to provide a button structure for an electronic apparatus allowing key top members and a base thereof separated from each other and thereby obviating wastes on a production line as far as possible to thereby reduce the cost and realize recycling.
A button structure for an electronic apparatus of the present invention includes a printed circuit board having switch devices arranged thereon, Belleville springs corresponding one-to-one to the switch devices and each snapping through when pressed, and buttons corresponding one-to-one to the switch devices. The buttons each include a button body formed on a single flat base and connected to button bodies of the other buttons by flexible portions, an actuating portion extending to the vicinity of corresponding one of the Belleville springs, and a key top member removably fitted on the button body.