Cylindrical tappet

• US 4,739,675 A
• Filed: 10/25/1983
• Issued: 04/26/1988
• Est. Priority Date: 11/14/1980
• Status: Expired due to Fees

• Current Assignee: Calvin C. Connell
• Original Assignee: Calvin C. Connell
• Inventors: Connell, Calvin C.
• Primary Examiner(s): Smith, Gary L.
• Assistant Examiner(s): Lindsey, Rodney M.
• Application Number:
  US06/545,117
• Time in Patent Office: 1,645 Days
• Field of Search: 74/569, 123/90.48
• US Class Current: 74/569
• CPC Class Codes: F01L 1/14 Tappets hydraulic tappets for automatically adjusting or compensating clearance F01L1/24; Push rods
• CPC Class Codes: F01L 2307/00 Preventing the rotation of tappets
• CPC Class Codes: F16H 53/06 Cam-followers F16H53/08 takes precedence
• CPC Class Codes: Y10T 74/2107 Follower

Abstract

An improved cylindrical tappet for transmitting motion between a camshaft and a valve of an internal combustion engine. The tappet construction affords improved performance by permitting higher lift rates than possible with conventional tappet designs. In addition, cam and tappet face wear and cam walk are minimized due to the construction. The tappet consists of a body portion that is slidably supported in a bore of the engine adjacent to the cam lobe. The body portion has a pocket that is adapted to receive one end of a push rod for actuating the valve upon reciprocation of the tappet body portion. A follower portion is pivotally supported by the body portion about an axis that extends normally to the axis of rotation of the associated cam. The follower portion has a curved cylinder surface which engages the cam lobe and which has a substantially larger radius of curvature than the bore in which the tappet is supported. The pivotal support of the follower portion permits the follower face to maintain full face-to-face contact with the cam lobe.

Claims

1. A tappet for transmitting motion from a rotatable cam to a valve of an internal combustion engine, said tappet being slidably supported for reciprocation along a first axis in a cylindrical bore of the engine,

said tappet comprising a circular cylindrical body portion adapted to be slidably supported in the bore of the engine,

a cam follower portion on said tappet having a cam engaging face comprising a segment of a circular cylinder the axis of generation of which extends parallel to the axis of rotation of said engine cam and the radius of generation of which is substantially greater than the radius of generation of the circular body portion of said tappet, said cam follower portion being contained entirely within the circular cross section of the body portion of said tappet so as to be reciprocable within the bore in said engine, and

pivot means supporting the cam follower portion of said tappet for rotation relative to the body portion thereof about an axis extending at a right angle to the axis of reciprocation of said tappet and lying in a plane extending at a right angle to the axis of generation of the cam engaging face on the cam follower portion of said tappet.

2. A valve tappet as set forth in claim 1 wherein the cam follower portion on said tappet is sized so that it may be inserted into and through the supporting bore of the engine from the side opposite the cam.

3. A valve tappet as set forth in claim 1 wherein the cam follower portion is detachably connected to the body portion by said pivot means.

4. A valve tappet as set forth in claim 1 wherein the body portion has a cavity at one end thereof and the cam follower portion has a portion extending into said cavity, said pivot means for supporting the follower portion comprising a pin extending through the cam follower portion and supported by the body portion.