Patent ID: 7481629

Claim:
A radial piston pump comprising: a pump body ( 1 ) having a plurality of cylinders ( 3 ) with each cylinder containing a reciprocating piston ( 2 ), each of the plurality of cylinders ( 3 ) and the pistons ( 2 ) being aligned along a respective radial axis extending normal to rotational axis ( 24 ) of the radial piston pump; a slip ring assembly ( 9 ) comprising a radially inner cylindrical surface ( 28 ), a polygonal shaped radially outer surface having a plurality of radially outer planar surfaces ( 13 ) and a pair of opposed side surfaces, each of the radially outer planar surfaces ( 13 ) being engagable with only one of the pistons ( 2 ), and the slip ring assembly ( 9 ) further comprising at least one of: a plurality of symmetrically located through bores ( 10 ) extending through the slip ring assembly ( 9 ) substantially parallel to the rotational axis ( 24 ) to reduce a weight of the slip ring assembly ( 9 ) without causing any imbalance of the slip ring assembly ( 9 ), and at least one symmetrically located bore ( 10 ), extends partially through the slip ring assembly ( 9 ), located in at least one of opposed side surfaces to reduce the weight of the slip ring assembly ( 9 ) without causing any imbalance of the slip ring assembly ( 9 ); and a driven eccentric ( 4 ) engaging the radially inner cylindrical surface ( 28 ) of the slip ring assembly ( 9 ) and being drivable about the rotational axis ( 24 ) such that each of the pistons ( 2 ) is sequentially biased between a suction thrust, during which fluid is drawn into the cylinder ( 3 ), and a pressure thrust, during which the fluid is expelled out of the cylinder ( 3 ) into a sump ( 15 ), and a number of the outer planar surfaces ( 13 ) is equal to a number of the pistons ( 2 ).