Patent ID: 7753180

Claim:
A magnetorheological (MR) piston comprising: a) an MR piston core including an end and including a bypass passageway; b) an MR piston end plate covering the end to define a chamber between the end and the MR piston end plate and having a through passageway aligned with the bypass passageway at the chamber; c) a shim disc disposed in the chamber apart from the bypass and through passageways; and d) a flexible orifice disc disposed in the chamber, facing the shim disc, extending past the shim disc and the bypass passageway, including an orifice aligned with the bypass passageway at the chamber, and including an additional orifice, wherein under fluid pressure in a first direction the orifice disc lies substantially flat against one of the end and the MR piston end plate allowing fluid communication between the bypass passageway and the through passageway by way of the orifice but not by way of the additional orifice, and wherein under fluid pressure in an opposite second direction the orifice disc is deflected by the presence of the shim disc to lift the additional orifice from the one of the end and the MR piston end plate allowing fluid communication between the bypass passageway and the through passageway by way of the orifice and by way of the additional orifice.