GB743267A - Improvements in or relating to anti-backlash bolt assemblies - Google Patents

Abstract

743,267. Bolting; hinges. NORTHROP AIRCRAFT, Inc. March 31, 1953 [May 31, 1952], No. 8880/53. Classes 65 (2) and 89 (I). [Also in Groups XXXIII and XXXIV] A hinge-bolt assembly for insertion in a bcre comprises a bolt, sleeve-means slidable on the bolt and in the bore, at least one ring of elastic material around the bolt and having an outer diameter substantially the same as the sleeve, and means for forcing the sleeve to deform the ring laterally against the bolt and the bore wall to bind the bolt in the bore. The assembly is shown applied to the hinging of an aircraft control surface A, Fig. 3, the bolt having a head 40, shank 41 and a reduced-diameter threaded end 42 for a locknut 51 and washer 50. Sleeves 44a ... 44c are fitted on the shank and separated by pairs of rings 45, e.g. of silicone rubber. The assembly passes through aligned bores 32 in a U-shaped bracket fixed to the surface A, and engages, between the arms 22 of the bracket, selfaligning bearing 28 comprising an outer member 26 having a part spherical track 27 engaging a similar track on an intermediate member 28 between which and an inner member 30 are rollers 29, said bearing being carried by an arm 6 forming part of a hydraulic servomotor for moving the aileron. On tightening the nut 51, the sleeves deform the rings to engage the shank and walls of the bores and eliminate backlash. The sleeves and rings are preassembled on the bolt and held by a cross pin 47, Fig. 4, engaging a notch 46 in sleeve 44c. In an alternative construction, e.g. for binding the bolt in bores 32 only, the assembly comprises a bolt 60, Fig. 6, receiving, on reduced-diameter parts at both ends, rings 62 and sleeves 64 which are caused to deform the rings when nuts 67 are tightened. The bolts are of such length that the washers 51 do not engage the bracket.