GB707111A - Bearings and bushes - Google Patents

Abstract

707,111. Bearings. BALDWIN CO. Dec. 27, 1951, No. 30238/51. Class 12(1) [Also in Groups VIII, XXV and XXXVIII] A bearing assembly comprises a holder having a hole therein and, fitted in the'hole, a bearing bush comprising a tubular sleeve fabricated from flexible strands and rigidified by a superficial cementitous coating which penetrates only partially into the sleeve so as to leave the inner portion thereof free of the coating. In one embodiment nylon strands in the form of either cords, thread or yarn, are braided into a tube 1, Fig. 2, which is tensioned longitudinally to reduce its diameter and is passed between brushes 4 which apply to it an exterior coating 3 of nitro-ecllulose lacquer cement. A pair of stiffened tubes 5, Fig. 4, are pushed from either side with a rotary motion into bearing holes 7 in the respective ends of a bifurcated hinge member 6 which constitutes the support for a centre pin of a pianoforte action and is preferably made from wood with the grain extending transversely to the holes. The tubes on reaching the inner ends of the holes are trimmed off by rotary knives 81. Members 9 apply solvent to the exteriors of the tubes to soften the coating, so that the latter on subsequently hardening will adhere to the interior of the bearing holes. In a modification the strands are braided around a core wire which is made from an alloy of lead and tin, and has a diameter slightly less than that of the corresponding centre pin. The tubular assembly 24, Fig. 8, so constituted is drawn through a coating bath containing liquid cement 31; passing successively through aligned holes 25, 26, 27 in dies which divide the bath into a pair of compartments 28, 29. Hole 25 is a close fit to prevent leakage of cement, hole 26 serves to brush the cement into the outer strands and hole 27 regulates the thickness of the coating. In a further modification the stiffened tube 32 issuing from the bath is passed through a final die which shaves the hardened exterior to the required diameter. After the tube is pushed into a bearing hole and trimmed to length the core is ejected by means of a punch which is lubricated with soap solution, the latter being deposited on the inside of the bush to form, upon evaporation, a lubricant for the pin. The core wire may be moistened with soap solution before the strands are braided thereon. The strands may alternatively be of wool, silk or rubber.