GB1254877A - Hydraulic piston and cylinder devices - Google Patents

Abstract

1,254,877. Bearings; linkwork; valves. PRESSURE DYNAMICS Ltd. 19 Jan., 1970 [19 Oct., 1968], No. 49706/68. Headings F2A, F2K and F2V. [Also in Division F1] A thrust bearing for resisting the axial load on the shaft 11 of a swash plate pump or motor (see Division Fl) is arranged to emit a signal when overloaded. The bearing shown in Fig. 2 comprises collars 76, 77 fixed to the shaft 11 and annular members 83, 84 supported by a housing 18, 19, 20 in a position between the collars. Springs 86 urge the members 83, 84 into abutment with the collars 76, 77; the springs being compressed when an overload occurs thereby to decrease the width of an annular chamber 94 between the members 83, 84. Located in the chamber 94 is a row of mutually contacting balls in a zig-zag configuration, Figs. 3 and 4 (not shown), or a zig-zag metal strip, the row or strip increasing in length when the chamber 94 decreases in width. This increase in length operates the plunger of a micro-switch (not shown). In a modified bearing, Fig. 6 (not shown), a chamber analogous to the chamber 94 is filled with liquid, the displacement of which is used to operate a pressure switch. The embodiment of Fig. 7 operates in the manner of a valve and bearing. Spaced collars 146, 147 on a shaft 141 abut with opposite faces on a non-rotating member 145 keyed for axial movement to a housing 142. The adjacent ends of the housing 142 and member 145 are engaged by end members 156, 157 urged by spring 159 and fluid supplied to cavities 163, 164. When axial movement of the shaft occurs the member 145 moves one or other end members 156 or 157 away from engagement with the housing 142 whereby liquid from the respective cavity flows into passages 169 or 171 and thence to an outlet port 170.