Patent ID: 7484488

Claim:
A tappet for use in an internal combustion engine including an engine poppet valve and a camshaft having a cam lobe profile including a base circle portion and a lift portion, said tappet being operably disposed between said cam lobe profile and said engine poppet valve; said tappet comprising an inverted, cup-shaped first follower adapted for engagement with said cam lobe profile, and an upright, cup-shaped second follower disposed for reciprocable movement within said first follower, and adapted for engagement with said engine poppet valve; a lost motion spring operably associated with said first and second followers and biasing said first follower toward an extended position, relative to said second follower, and into engagement with said base circle portion of said cam lobe profile; said tappet comprising: (a) a latching mechanism operably associated with said second follower and including a latch member moveable between a retracted, disengaged position and an extended, engaged position engaging said first follower to fix said first follower in said extended position, relative to said second follower and provide a high lift of said engine poppet valve; and (b) said first follower having a first portion defining a first stop surface and said second follower having a second portion defining a second stop surface, the first and second stop surfaces being aligned such that, when said latch member is in said retracted, disengaged position, engagement of said lift portion of said cam lobe profile with said first follower moves said first follower toward said engine poppet valve, compressing said lost motion spring until said first stop surface contacts said second stop surface, and thereafter, further movement of said first follower moves said second follower to provide a low lift of said engine poppet valve.