GB1206414A - Pressure operated actuator - Google Patents

Abstract

1,206,414. Vehicle braking systems. E. E. ANDERSSON. 19 Dec., 1967 [20 Dec., 1966; 19 Oct., 1967], No. 57683/67. Heading F2F. [Also in Division F1] An actuator rod 2, Fig. 1, is urged axially, e.g. to the right by hydraulic pressure acting on the left-hand face of each of at least two flexible diaphragms 5 secured at their reinforced central areas to the rod at spaced distances therealong; the diaphragms being sealingly held at 19a, 19b at their peripheries by rigid stationary dished metal plates 7, 8 surrounded by a casing 1 and the pressure fluid being admitted through a casing port 12 and apertures 7b in the extreme left-hand plate 8 to a chamber 6 bounded by the left-hand diaphragm 5 which is thereby urged to the right, and the pressure fluid also being fed to the chambers 6 on the left-hand face of each of the succeeding diaphragms 5 through spaces between the casing 1 and seals 19a, 19b and apertures 7b in the plates 8. To urge the diaphragms 5 and hence rod 2 to the left, pressure fluid is admitted through a port 13 to a chamber 9 bounded by the end wall of the casing and the right-hand diaphragm 5, and fluid also passes through a radial port 2b in rod 2, along a longitudinal slot 2c and radial ports 2b to the remaining chambers 9, thereby flexing all three diaphragms. Fig. 2 shows a vehicle brake actuator wherein the rod 2 is connected to a rod 20 which acts on a brake fork 21 connected to a piston 23 biased to the right by a spring 24 when supply of compressed air through a port 25 is interrupted thereby applying parking brake. In normal operation compressed air holds the piston 23 against spring 24, and on application of hydraulic pressure through port 12 to chambers 6, which on the right-hand side are bounded by diaphragms 5 the rod 2 is moved to the right. Return is effected by a spring 27.