Patent ID: 7568461

Claim:
A roller tappet for use with a cam actuated mechanism, the tappet comprising: a follower body having upper and lower sides and a generally cylindrical periphery, a guide sleeve fitted around the periphery and extending from the lower side to and a substantial distance beyond the upper side of the follower body, and a cylindrical follower roller rotatable about a roller axis in a part cylindrical recess extending laterally across the lower side of the follower body, the recess having laterally open ends closed by a generally cylindrical inner wall of the guide sleeve surrounding the follower body; the follower roller being engagable with a rotatable cam of a liquid lubricated mechanism for axially reciprocating the tappet within a cylinder of the mechanism, the upper side of the follower body being engagable with a shoe of a high pressure fuel pump plunger for reciprocating the plunger to pump liquid fuel, and the guide sleeve receiving a spring operable to bias the follower roller against the cam and the plunger shoe against the upper side of the follower body to operate the pumping mechanism; the follower roller being free to move laterally in the recess and having laterally opposite ends engagable with the inner wall of the guide sleeve to limit lateral motion of the roller within the recess; at least one of the roller ends being formed with an annulus engagable with the sleeve inner wall at radial locations spaced outward of the roller axis and inward of the outer diameter of the roller, portions of the at least one roller end both inward and outward of the annulus being configured to prevent contact with the inner wall of the guide sleeve; whereby external lubricant reaching the annulus and the skirt interior prevents excessive wear at the roller/wall interface.