Patent ID: 6971639

Claim:
An orifice device for use with a vibration absorption device and adapted to be disposed within a fluid chamber of the vibration absorption device, the fluid chamber being defined by at least a wall portion made of resilient material, comprising: an orifice casing; a retaining cover; a membrane made of resilient material and arranged and constructed to be clamped between the orifice casing and the retaining cover in an axial direction; and a lock mechanism arranged and constructed to lock the orifice casing and the retaining cover together without substantial movement relative to each other in the axial direction as the orifice casing and the retaining cover rotate relative to each other about an axis while the orifice casing and the retaining cover are lapped with each other; wherein the lock mechanism comprises a first engaging member and a second engaging member disposed on one and the other of the orifice casing and the retaining cover, respectively; the first engaging member includes an engaging projection in the axial direction and has an engaging recess; the second engaging member includes an engaging hole and an engaging edge.