Variable jaws for vane pump

Claim 1

In a vane pump having a plurality of radially movable vanes on a rotor rotatably mounted in a pumping zone, the combination comprising: a pair of identically formed, radially slidable jaws for adjusting the volume of said pumping zone, each of said jaws comprising a body portion having an elongated arcuate wall for defining one side of the pumping zone, a pair of horizontally spaced and parallel ribs projecting outwardly from one side of said body portion and defining a guide space therebetween, said pair of ribs each having a first surface extending in tangential relationship to said wall, a single rib projecting outwardly from the other side of said body portion and extending coextensively and in parallel relationship to said pair of ribs, said single rib having a second surface extending in tangential relationship to said wall and parallel to said first surfaces on said pair of ribs, said guide space and said single rib being of such dimensions that two of said body portions can interfit each other with said single rib of one body portion being received between a pair of ribs of the mating body portion in a snug sliding fit relationship and said walls of said body portion cooperating to define said pumping zone, said single rib and said pair of ribs extending in overlapping relationship to said body portion whereby to create a continuous wall for said pumping zone at any spacing between said jaws.