Automatic clasp for wristwatch strap
AssigneeG & F Chatelain SA
InventorsClaude Grossiord, Jean-Louis Bohrer, Frédéric Nicolet
Life of this patent
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Abstract
A clasp and a production method thereof. The inventive clasp includes at least one main element (1) and at least one element (3) which pivots in relation to the main element. The clasp is characterised in that each of the aforementioned elements (1, 3) includes two longitudinal arms which are rolled up to form a hinge (7, 15) . Moreover, at least one of the ends of one of the elements (1, 3) includes a flexion spring (11) which can rest against the other element (3, 1) for the elastic support thereof and each arm (5, 13) of the main element (1) and the pivoting element (3) is provided with at least one longitudinal stiffening rib (20, 22).
Claims11
Method for manufacturing a clasp, particularly for wristwatch strap, from a metal strip, of the type comprising a main element and at least one pivoting element, which are connected at one of their respective ends by an articulation, a flexion spring fastened with one of these elements being applied, at least in position of closure, on the other element in order to support it elastically in this position of closure, characterized in that it comprises the steps consisting in:
- using a strip whose stiffness is the one desired for the spring,
- making, by cut-out, a blank of each of these elements, so as to form on each of them at least two longitudinal arms, and on the main element two recesses inside the two arms forming therebetween a central flexion spring,
- subjecting these arms to an annealing exclusively at their ends so as to allow rolling thereof,
- increasing the stiffness of these arms by making at least one rib along the longitudinal axis thereof.
Dependencies are inferred from the claim text.