Balance mechanism for a clockwork movement

Abstract

The balance (1) has an axle (2) made up of steel for supporting a balance wheel comprising arms (4) connected with a felloe (3). The arms and felloe are made up of a single piece with titanium or titanium-base alloy. The arms are radially projected from a drilled central part (5) that moves on a bearing of the axle by supporting against a shoulder.

Description

technical field

[0001] The invention relates to a balance for a timepiece movement comprising a staff, a rim and an arm connecting the rim to the staff, and the balance The wheel mechanism is intended to interact with a hairspring to form, in a conventional manner, a mechanical oscillator that determines the fundamental frequency of a timepiece, especially a watch movement. A known construction of a balance of this type is shown, for example, in CH Patent No. 494992. technical background

[0002] Currently, in balances for watch movements, the wheel-shaped parts including the rim (or tire) and the arms are made of copper-based alloys, especially beryllium-copper alloys, German silver or nickel. This alloy has an advantageous combination of properties including, inter alia, its non-magnetic properties, good chemical stability and sufficient mechanical properties. The density of these alloys is greater than 8kg / dm 3 . Their coefficient of thermal expansion is not particula...

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