A lifter includes a roller caused to abut against a cam thereby to be pressed and a lifter body rotatably supporting the roller and housed in a guide hole of a lifter guide so as to be reciprocable in the guide hole. The lifter body includes a cylindrical part and a rotation stopper. The cylindrical part has an outer periphery formed into a cylindrical shape such that the outer periphery is slidable on an inner periphery of the guide hole. The cylindrical part has one of two axial ends, the one end being formed with a skirt covering the roller. The rotation stopper is formed to protrude outward from the other axial end of the cylindrical part, the other axial end being located opposite a side where the skirt is located. The rotation stopper prevents the lifter body from being rotated about an axis thereof relative to the lifter guide.

A fuel pump assembly for an internal combustion engine includes a fuel pump housing, a cylindrical bore defined in the fuel pump housing, and a tappet assembly received in the cylindrical bore. The tappet assembly includes a one-piece shoe having a recess disposed in a bottom portion thereof, and a roller that is partially received within the recess and configured to rotate about a roller axis.

A valve lifter assembly for an engine may include a valve lifter body, a roller pin mounted in the valve lifter body and having a crowned barrel portion, and a substantially cylindrical roller mounted about the crowned barrel portion of the roller pin. The roller may have a crowned outer surface with a cylindrical center portion having a constant outer diameter equal to a roller maximum outer diameter, and oppositely disposed variable outer diameter outer portions extending outwardly from either side of the cylindrical center portion toward corresponding roller ends of the roller with a roller outer diameter decreasing as the variable outer diameter outer portions extend outwardly from the cylindrical center portion. The valve lifter assembly may further include a clip having engagement surfaces that are machined to have complimentary shapes to corresponding engagement surfaces of the valve lifter body.

A mechanical system comprising: a tappet, including a body; an insert mounted in the body; a pin extending along a first axis; and a roller element movable in rotation relative to the pin around the first axis. The insert supports the pin, while the body supports the insert, along at least one first direction parallel to a second axis which is perpendicular to the first axis. The mechanical system can be integrated into an injection pump and/or a valve actuator.

A tappet assembly for use in translating force between a camshaft lobe and a fuel pump assembly via reciprocal movement within a tappet cylinder having a guide slot. The tappet assembly includes a bearing assembly having a shaft and a bearing rotatably supported by the shaft for engaging the lobe. An intermediate element has a first aperture, a shelf for engaging the fuel pump assembly, and a pair of arc-shaped bearing surfaces rotatably engaging the shaft when the bearing engages the lobe and the shelf engages the fuel pump assembly. An annular body has a second aperture and at least one stop member abutting the intermediate element to align the first aperture with the second aperture. An anti-rotation clip is disposed so as to extend through the apertures and cooperates with the stop member to substantially prevent rotational and axial movement of the intermediate element with respect to the body.

A mechanical system, comprising a support element having an outer surface adapted to slide in a housing receiving the mechanical system, a pin extending along a first axis and comprising two opposite ends, each adapted to be fitted in the support element for radial and/or axial retention of the pin relative to the first axis, and a roller element movable in rotation relative to the pin around the first axis. The mechanical system comprises at least one outer insert positioned at the outer surface of the support element. The mechanical system can be integrated into either an injection pump or a valve actuator.

In one embodiment, a lifter assembly comprises a lifter having a latching mechanism, a slot arranged on an outer wall of the lifter and comprising an inlet that provides access to the latching mechanism, and a pin comprising a fluid channel. The latching mechanism is switchable between a latched position and an unlatched position. The pin is configured to interface with the slot such that the lifter is prevented from rotation about a lifter axis. The fluid channel is configured to be fluidly coupled to the inlet of the slot.