Abstract

A reversing mechanism for a reciprocating pump provided in a common housing or module removably secured to the pump body adjacent to the pump shaft. The module housing includes top and bottom pieces which slide together with suitable tongue and groove elements. The top piece houses a reversing valve, and has a slot on the underside thereof for receiving a yoke member of the reversing mechanism. The sides of the slot form bearing surfaces parallel to the longitudinal axis of the pump shaft. The yoke slides or reciprocates on these bearing surfaces. The bottom piece comprises a support for opposed snap-acting springs. The yoke has a pair of upwardly extending spaced arms for actuating opposite ends of the reversing valve when it reciprocates, and a pair of downwardly extending spaced arms for engaging a transverse pin in the pump shaft as the shaft reciprocates. A central pin in the yoke couples it to the snap-acting springs. A special nested bearing structure is provided for the snap-acting springs. The pump is provided with coded inlet and outlet valve cartridges to preclude the improper assembly thereof within the pump housing.