Timepiece barrel assembly with reduced core diameter
AssigneeETA SA Manufacture Horlogere Suisse
InventorsLaurent Kaelin, Baptist Wyssbrod, Arthur Queval
Life of this patent
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Abstract
A timepiece barrel assembly, including a barrel mainspring mounted between a barrel drum and a receiving surface of a barrel core coaxial to the drum. The spring is made of a multiphase, cobalt-nickel-chromium based alloy, having a Young's modulus of between 200 and 240 GPa and a shear modulus of between 80 and 100 GPa, and having a width to thickness ratio of between 9 and 21, and the maximum radius of the steel or stainless steel core relative to its pivot axis is less than nine times the maximum thickness of the spring, and the barrel assembly includes, on the spring or the drum, a mechanism limiting longitudinal clearance, towards the pivot axis, between the drum and the mainspring.
Claims15
A timepiece barrel assembly, comprising:
- at least one barrel mainspring mounted between, at a first end a barrel drum, and at a second end, a receiving surface comprised in a barrel core coaxial to the drum about a pivot axis;
- wherein the mainspring is made of a multiphase, cobalt-nickel-chromium based alloy, comprising 44 to 46% cobalt, 20 to 22% nickel, 17 to 19% chromium, 4 to 6% iron, 3 to 5% tungsten, 3 to 5% molybdenum, 0 to 2% titanium, 0 to 1% beryllium, and having a Young's modulus of between 200 and 240 GPa and a shear modulus of between 80 and 100 GPa, and having a width to thickness ratio of between 9 and 21,
- wherein the barrel core is a steel or stainless steel core having a maximum radius relative to the pivot axis less than nine times a maximum thickness of the mainspring, and
- wherein the barrel assembly includes, on the mainspring or the drum, a means for limiting longitudinal clearance, in a direction of the pivot axis, between the drum and the mainspring.
Dependencies are inferred from the claim text.