Patent ID: 7066310
Filing Date: 2006-06-27
Classification: E05C,F16F

Abstract:
1. A piston cylinder unit comprising: a closed cylinder having an end wall; a piston rod guided through said end wall; a piston fixed to said piston rod for axial displacement in said cylinder, said piston dividing said cylinder into a working space surrounding the piston rod and a working space away from the piston rod; an annular seal between said piston and said cylinder; a volume equalizing space in said piston; a first valve which can be opened under pressure to admit fluid from said working space away from said piston rod to said volume equalizing space; a second valve which can be opened under pressure to admit fluid from said working space surrounding said piston rod to said volume equalizing space; at least one of said first and second valves comprising: a first non-return valve which can admit fluid from said volume equalizing space to said working space away from said piston rod; and a second non-return valve which can admit fluid from said volume equalizing space to said working space surrounding said piston rod.