Timepiece construction
AssigneeKabushiki Kaisha Suwa Seikosha
InventorsTomio Ota, Mamoru Miyasaka, Imao Hiraga
Life of this patent
Estimating the term…
Abstract
A precision, reliable, analog timepiece uses plastic frame elements reinforced with metal, and plastic wheel and pinions pivoting in holes formed in the plastic of the frame elements. The plastic frame elements are separated into portions corresponding to the functional timepiece portions. Exposed areas of the reinforcing metal provide reference locations in molding the frame elements and for component mounting. The entire timepiece is assembled from one side of a base frame element.
Claims10
An electronic wristwatch driven by a stepping motor comprising:
- at least a first frame and a second frame, said first and second frames being formed of metal plates with plastic layers integrated to said metal plates, said plastic layers being substantially separated, in a plan view, into concave and convex portions, the concave and convex portions at each said separated plan view portion being adapted to mount components substantially of a functional block of said wristwatch;
- a gear train including a rotor portion of said stepping motor for driving said display, said gear train being positioned between said first and second frames;
- a ring-shaped date dial and a date dial guard disposed between a dial and one of said first and second frames;
- said date dial guard supporting said ring-shaped date dial, said dial guard being a metal plate, said first and second frames and said date dial guard each having a hole, said holes being concentric;
- a threaded tube fixed in the concentric hole of the other one of said first and second frame;
- a bridge screw passing through said concentric holes from the side of said dials to engage said threaded tube, said first and second frames and said date dial guard being supported together in common by said bridge screw when said gear train and said rotor are arranged on the concave portion of said plastic layer, at least a part of the convex portion being used as a spacer between said two frames, the heads of said threaded tube and said bridge screw being respectively overlapped with the metal plate in the frame and the metal of the dial guard so that the axial forces created by the bridge screw are supported by the metal of the frame and dial guard.
An electric wristwatch as claimed in claim 4, and further comprising a bearing, said bearing being supported in said plastic layer and located in an opening in said metal plate.
An electronic wristwatch with dial and case comprising at least first and second frames holding a gear train for display therebetween, said first frame being provided adjacent the dial of said wristwatch and said second frame being provided on the side of the back of said case, said second frame being formed of a metal plate covering generally the entire movement of said wristwatch and a plastic layer integrally joined to said metal plate, said plastic layer including concave and convex portions and a radial shaft bearing portion for supporting shafts of said gear train, and a hand setting shaft extending generally parallel to said frames, and a bearing in said plastic layer for said hand setting shaft being provided reinforced by said metal plate to which at least said second frame is connected, said bearing supporting said hand setting shaft in the direction of thrust when said setting shaft is rotated for hand setting.
Dependencies are inferred from the claim text.