Reversing valve construction and piston head assembly therefor and methods of making the same

Claim 1

In a reversing valve construction comprising a housing means having an internal peripheral surface, a movable valve member disposed in said housing means, a piston unit disposed in said housing means and being interconnected to said valve member, said piston unit having opposed piston heads that define a main chamber of said housing means therebetween, said housing means having end portions respectively cooperating with said piston heads to define a pair of control chambers therewith and separated from said main chamber by said piston heads, said end portions respectively having valve seats facing said control chambers in directions substantially transverse to the direction of movement of said piston unit in said housing means, each said piston head having a front disc member and a backing plate, each said piston head having a flexible seal member secured between its respective front disc member and backing plate, each said seal member having an integral peripheral skirt, each said piston head having biasing means urging its respective skirt of its respective seal member into sliding and sealing engagement with said internal peripheral surface of said housing means, the improvement wherein each said biasing means comprises an annular resilient O-ring member separate from its respective seal member and being carried by one of said backing plate and said front disc member of its respective piston head so as to radially engage and urge its respective skirt radially outwardly into said sliding and sealing engagement, each said seal member of its respective piston head being adapted to close its respective valve seat when moved thereagainst by said piston unit.