Patent ID: 6239391
Filing Date: 2001-05-29
Classification: H01H

Abstract:
A keyboard assembly comprising:a support plate;membrane switches formed on the support plate;a housing plate disposed on the membrane switches; andkey tops respectively supported vertically movably on a plurality of convex-shaped key top housings, the key top housings being arranged in rows on an upper surface side of the housing plate,wherein a torsion bar is attached to a back side of at least one of the key tops, support members of a hollow structure are erected on the housing plate on opposing sides of the key top housing which supports a key top with the torsion bar attached thereto, retaining holes to retain end portions of the torsion bar are formed respectively in upper portions of the support members, while on bottom sides of the support members are respectively formed through holes which extend through the housing plate and which are open to a bottom side of the housing plate, and a sheet member is disposed between the housing plate and the membrane switches, the sheet member comprising convex-shaped spring portions aligned respectively with the plural key top housings, convex-shaped waterproofing protuberances positioned respectively in opening portions of the through holes at opposing ends of the key top housing formed with the torsion bar to close the opening portions, a sheet body portion which renders the plural spring portions and the plural waterproofing protuberances integral with each other, and the waterproofing protuberances are larger than the opening portions of the through holes and cover an entirety of the opening portions.