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US 4,077,201 AGranted
Extractable barrel-arbor
AssigneeETA A.G. Ebauches-Fabrik
InventorFriedrich Perrot
Life of this patent
Estimating the term…
Abstract
An improved extractable barrel-arbor for a watch movement is provided with first and second end cylindrical pivot bearing surfaces, and a central cylindrical surface containing a hook. The radius of the central surface is less than the radius of the first and second end cylindrical surfaces while the distance between the axis of the barrel-arbor and the outer hooking edge of the hook is equal to the radius of at least one of the first and second pivot bearing surfaces.
Claims8
In a watch movement having a bottom plate;
- a ratchet wheel;
- a main spring having one end forming an eye;
- and a barrel-arbor having a first end pivoting in said bottom plate, a second end attached to said ratchet wheel, a central cylindrical surface supporting an inner end of said eye of said mainspring, and a hook projecting from said central cylindrical surface for attaching said main spring eye to said barrel-arbor;
- the improvement in said barrel-arbor comprising:
- a first cylindrical pivot-bearing surface coaxial with and adjacent to said central cylindrical surface at said first end, the radius of said first cylindrical pivot-bearing surface being greater than that of said central cylindrical surface,
- a second cylindrical pivot-bearing surface coaxial with and adjacent to said central cylindrical surface at said second end, the radius of said second cylindrical pivot-bearing surface being equal to or greater than that of said first cylindrical pivot-bearing surface, and
- an outer hooking edge of said hook situated at a radial distance from the axis of said barrel-arbor equal to said radius of said first cylindrical pivot-bearing surface.
4 more elements
Dependencies are inferred from the claim text.