Unitary cam follower and valve preload spring for a desmodromic valve mechanism

摘要

A unitary cam follower and valve preload spring for a desmodromic valve mechanism having opening and closing cams mounted in parallel on an overhead camshaft so as to facilitate positive bidirectional drive of a valve. The device comprises a generally tubular spring member of oblong transverse cross-section, a shaped extension spring, preferably a band or basket. The spring member is configured to be nonrotatably mounted on the camshaft with its longitudinal axis parallel to the camshaft axis and its major axis aligned with the valve stem axis, substantially surrounding the opening and closing cams circumferentially and engaging the valve stem and closing cam so as to pull the valve stem in response to an upward force applied to the upper portion of the spring member by the closing cam. The spring member is further configured to elongate along its major axis in response to tension applied thereto during assembly so as to preload the valve stem, and it has an effective spring rate which varies depending on conditions.

主权项

1. A unitary cam follower and valve preload spring for a desmodromic valve mechanism having opening and closing cams mounted in parallel on an overhead camshaft so as to facilitate positive bidirectional drive of a valve, comprising:
a one-piece, generally tubular spring member of oblong transverse cross-section having a major axis and minor axis, configured to be nonrotatably mounted on the camshaft with its longitudinal axis parallel to the camshaft axis and its major axis aligned with the valve stem axis, substantially surrounding the opening and closing cams circumferentially and engaging the valve stem and closing cam so as to pull the valve stem in response to an upward force applied to the upper portion of said spring member by the closing cam, said spring member further configured to elongate along its major axis in response to tension applied thereto while engaging it with the valve stem and closing cam during assembly so as to preload the valve stem.