BALANCE SPRING OF REDUCED SIZE OF CONSTANT DOUBLE CROSS-SECTION Russian patent published in 2020 - IPC F16F5/00 G04B1/00 

FIELD: balance springs.

SUBSTANCE: resonator includes balance interacting with balance spring. One-piece balanced spring comprises a single tape wound around itself between internal coil and outer coil. At rest the belt comprises first and second sections. At first section located between end of inner coil and penultimate turn, pitch between turns is constantly increased so that when compression angle of balance spring is 360°, distance between adjacent turns from inner coil to penultimate turn is constant. Second section is continuation of the first one and is located between the beginning of the penultimate turn and the end of the outer coil. At second section pitch between turns is constantly increasing so that when expansion angle of balance spring is 360°, between penultimate turn and outer coil there is minimum distance to prevent any contacts between them. Second portion comprises a first portion, the cross-section of which is substantially identical to the cross-section in the first portion, and second part, which is continuation of first part, and which cross section is increased.

EFFECT: enabling minimization of spring sizes without loss of timing.

7 cl, 6 dwg