Patent ID: 7584737

Claim:
A power transmission mechanism for conversion between linear movements and rotary motions, comprising: an internal groove cam capable of rotating about an axis thereof, comprising a continuous cam groove formed in the wall of a cylindrical inner cavity formed by the internal groove cam; a cam box accommodating and supporting the internal groove cam, which comprises a cover on the top thereof and a fixed rail mounted below the cover and extending into the cylindrical inner cavity formed by the internal groove cam; an assembly for linear reciprocating movement including: a roller shaft provided perpendicular to the axis of the internal groove cam, a primary roller and a secondary roller mounted adjacent to each other at each end of the roller shaft, both rollers mounted into the cam groove for rolling in the cam groove, and a guiding member provided on the roller shaft and moving along the rail, wherein the primary roller, the secondary roller and the roller shaft form a non-cantilevered structure freely supported at least at two ends thereof in the internal groove cam; wherein the primary roller and the secondary roller move in the cam groove, in conjunction with the simultaneous movement of the guiding member along the fixed rail, to actuate the movement of the roller shaft.