GB375354A - Improvements relating to oscillating pivots - Google Patents

Abstract

375,354. Bearings for weighing- apparatus. FEWSTER, T. H., National Physical Laboratory, Teddington, Middlesex. March 23, 1931, No. 8905. [Class 143.] In an oscillating pivot for delicate balances, of the kind in which flat springs in planes substantially radial to the axis of the pivot are arranged at angles to each other, the pivot being maintained in position by the inclined tensions in the springs and allowed to oscillate by flexure of the springs, the main spring which supports the resultant force on the pivot is connected to the pivot centrally in respect of the length thereof, and the other springs are connected to the outer portions of the pivot. The springs are preferably arranged in radial planes in three sets at 120‹; one or more of the springs is arranged at an angle to the radius to resist axial forces. The spindle A, which has eccentric extensions a for attachment to the oscillating part of the apparatus, is suspended from the bracket B by three sets of springs C, D, E, of which the main set C takes the vertical load and the auxiliary sets D, E are inclined to the radial direction to take any axial load. The spindle is cut away to its diameter at the required angles to present flat surfaces for attachment of the springs, and is further cut away to allow slight flexure of the free parts of the springs. The springs are attached to the spindle by being bent over keep plates J bolted to the spindle ; this construction allows them to be self-aligning and therefore uniformly stressed over their width. They are similarly attached to the bracket B, but the bolts attaching the springs E to the bracket are provided with eccentric bushes O to enable the system to be tightened up on assembly.