GB994262A - Improvements in or relating to reciprocating pumps - Google Patents

Abstract

994,262. Reciprocating pumps. H. G. ORAM. May 16, 1963 [Feb. 23, 1962], No. 7127/62. Heading F1A. In a swash plate pump, the cylinders are housed within the rotor of an electric motor and rotate therewith. The pump cylinders are mounted in the laminations of the rotor 6 which rotates about a fixed shaft 5 and the piston shoes 25 bear on a thrust plate 26 mounted in a pivoted member 89 (Fig. 5). Pressure liquid passes from the outlet 23 through passages 36, 33, 119, 120, 104 into an enlarged portion 93A of a cylinder 93. The liquid passes through holes 106 in a flange of a piston 95 and acts on the piston in opposition to a spring 99 and to a spring loaded piston 96 to vary the swash plate angle. Above a pre-determined level, the liquid moves a spring loaded valve stem 119 and liquid flows along a path 121 to a port 123. A pipe (not shown) connects ports 123, 107 and pressure liquid acts on the inside of the piston 95 to reduce the pump output to a minimum. In an alternative embodiment, the cylinders 11 are in a block 175 which is housed within and keyed to the rotor 6 (Fig. 6). The swash plate is mounted in a yoke 190 which is tiltable between stops 219 about the pintles 191 of a trunnion. A yoke pin 188 engages in a pin 207A which is slidable in an adjustable spool 207. Pressure fluid passes through passages 200, 201 to act on a springloaded rod 181 acting on a plate 182 to maintain the piston shoes in contact with the thrust plate 184. Further fluid flows through passages 213, 214, 215, 217 to a chamber 218 thereby forcing flange 188A against a thrust washer 189 to maintain it in abutment with the surface 208B. The pressure also acts on a plug 186 to relieve the load on the thrust bearing 185 and the pintles 191. When the pumping direction is reversed, pressure fluid is led to a chamber 207B and thence to a chamber 188B in the yoke pin 188. In alternative embodiments a fixed angle swash plate may be used and the shaft 5 may rotate with the rotor 6. The shaft 5 and the swash plate may be rotatable relative to the valve plate 20 to reverse the direction of flow and the pistons may be spring loaded to maintain them in contact with the swash plate.