Dashpot with guided piston

Claim 1

A dashpot comprising A. a hollow cylinder substantially closed at one end thereof; B. piston means comprising i. a piston disposed in and slidable along said cylinder, said piston having an outer sidewall spaced inwardly from the inner sidewall of said cylinder; ii. fluid blocking means secured to said piston for movement therewith and having a flexible portion thereof disposed intermediate opposed sidewall portions of said piston and said cylinder respectively and effective to block passage of fluid therebetween; said piston and said fluid blocking means as a unit by themselves being configured and dimensioned for appreciable pivotal movement within said cylinder about axes transverse to said cylinder axis; and iii. at least one pair of guide means disposed on said piston for movement therewith, each guide means of said guide pair having an outer surface closely adjacent said cylinder inner sidewall, substantially circumferentially spaced from the outer surface of the other guide means of said guide pair, and configured and dimensioned to essentially preclude movement of a first magnitude of said piston means within said cylinder along a first axis substantially connecting said guide means of said guide pair while only limiting to a predetermined level movement of a second magnitude appreciably greater than said first magnitude of said piston means within said cylinder about a second axis parallel to said first axis; and C. a piston rod having a first end portion operatively connected to said piston for moving said piston and a second end portion adapted for connection with a member undergoing reciprocating motion along a path substantially, but not necessarily exactly, aligned with the axis of said cylinder; whereby said guide pair insures the effective blocking function of said blocking means by essentially precluding motion of said piston means within said cylinder along said first axis while limiting to an acceptable level motion of said piston means within said cylinder about said second axis in response to limited misalignment of the axis of said cylinder and the axis of said piston rod.