Fluid operated device with improved sealing means

Claim 1

A fluid operated device comprising: An elongated housing, defining an elongated interior cylinder, said housing having an elongated slot formed along one side and open to said cylinder, and an elongated abutment surface substantially parallel but spaced outwardly from each side of said slot, a piston longitudinally slidable mounted in said cylinder, said piston forming a first chamber in said cylinder between one end of said housing and one end of said piston and a second chamber in said cylinder between the other end of the housing and the other end of said piston, means for fluidly sealing said ends of said piston to said cylinder, means for fluidly sealing said slot along said chambers comprising: an elongated band constructed of a magnetic material and having a width greater than the width of said slot, means for securing said band within said cylinder and adjacent said slotted side of said housing so that one side of said band faces and covers said slot, means for magnetically attracting said band to said one side of said housing and across said slot, said magnetic attracting means comprising a pair of elongated magnets, each magnet having two opposed sides and two opposed edges and, means for securing said elongated magnets to said housing along opposite sides of said slot so that one edge of each elongated magnet is substantially flush with the inner surface of said cylinder wherein said securing means comprises a pair of elongated magnet retainers, each magnet retainer having an elongated first leg and a substantially perpendicular elongated second leg, means for attaching the first leg of each retainer to one of said magnets so that each magnet is sandwiched in between said first leg of its associated retainer and its associated side of said slot, and means for attaching the second leg of each retainer to said housing comprising a lip formed at the free edge of said second retainer leg which lockingly engages said housing abutment surface, and an elongated resilient wiper secured to the second leg of each magnet retainer said wipers each having an edge which extends over a portion of said slot so that said edges of said wipers are closely adjacent each other.