GB922052A - Main spring and bridle torque gauging apparatus - Google Patents

Abstract

922,052. Timepiece gauging apparatus. M. SCHMIDT. Sept. 19, 1961, No. 33473/61. Class 139. A mainspring and bridle torque gauge A, Fig. 1, is used with a lathe B to test the mainspring and bridle within a barrel E the arbor 10 of which is secured by a clamp 15 to the lathe spindle C. The gauge A includes a balancing spring 28, Fig. 3, connected to a spindle 26 having at one end a pointer 27 and, at the other end, a pinion 25 meshing with opposed crown gears 23, 24 freely rotatable on a shaft 20. Between the gears 23, 24 the shaft 20 carries a finger member 40 which, in accordance with the direction of rotation of the shaft, abuts one or other of two finger members 42, 41 extending from the gears 23, 24 respectively. The pointer 27 has a pin and slot connection with a maximum position pointer 39. A pin 17, Fig. 1, extends from the clamp 15 to abut a pin 18 extending from a crank arm 19 carried by the shaft 20. If the mainspring and bridle assembly is wound by rotating the lathe spindle C, the spring 28 of the gauge is stressed via the shaft 20, gear 23 or 24, pinion 25 and shaft 26. The operator senses the instant at which the bridle becomes effective and reverses the rotation of the lathe spindle C. The torsion of the bridle spring is indicated by the pointer 39 and the torsion of the mainspring by the pointer 27. The springs are matched if the pointers do not diverge by more than an amount defined by an extension 44 of the pointer 27.