Patent ID: 9033573
Filing Date: 2015-05-19
Classification: G04B

Abstract:
1. 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.