PURPOSE: To miniaturize a portable telephone set, to reduce the weight of the telephone set, to prevent a casing from being damaged and to relax the shock to an internal component by forming a part or all of the casings with a foaming member and making the rear face of the case abut on the surfaces of the internal component.
CONSTITUTION: The internal component 3 is set on a lower foaming casing 6 and an upper foaming case 7 is covered to form a space 8, the rear side of the casing 7 and the surface of the component 3 are abutted on each other and a secondary battery is integrated. Since the rigidity of the casing is increased by abutting the casings 6, 7 on the component 3 in such a manner, an inexpensive and easily formed plastic material on market is used, and even when the portable telephone set is dropped in mistake, the shock is relaxed since the casing is made of the foaming member, the damage of the casing is prevented and the influence of the shock on the component is reduced. Furthermore, since the casings 6,7 are made of the foaming materials, the specific gravity is small, the thickness of the casing is made thin and the further reduction in weight is attained.
NAKAMURA KOZABURO
YAMAMOTO FUMIO
MATSUYAMA KENTARO
OSE RYOJI
NAKAYAMA TADAMITSU
HITACHI CHEMICAL CO LTD
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