Arrangements for converting rotary motion into linear motion

Abstract

An arrangement for converting rotary motion of a camshaft into linear motion of a reciprocable valve employs a reciprocable cam which is rotatable with the camshaft but is radially displaceable relative to the camshaft which extends through a slot-shaped aperture in the reciprocable cam. The profile of the reciprocable cam is held in engagement with a fixed reference roller and the bucket of valve is held in engagement with output rings on the cam. In the course of rotation of the camshaft, the cam lobe causes radial displacement of the cam on the camshaft with attendant movement of the valve.

Description

Claims

1. An arrangement for converting rotary motion into linear motion, comprising: a first member; means supporting the first member for rotation about an axis; a second member; means guiding the second member for linear movement in a direction transverse to the axis of rotation of the first member; a follower member having a cam surface and carried by the first member for rotation with the first member around the axis of rotation of the first member; means guiding the follower member for limited linear displacement relative to the first member transversely of the axis of rotation of the first member; and a fixed reference point located at a predetermined distance from the axis of rotation of the first member; the follower member being disposed between the fixed reference point and the second member with the follower member held in contact with the second member and the cam surface of the follower member held in engagement with the reference point, whereby on rotation of the first member the follower member imparts linear movement to the second member in the direction transverse to the axis of rotation of the first member.

2. An arrangement according to claim 1, in which the first member extends through an aperture in the follower member, the aperture being elongated in the direction transverse to the axis of rotation and the cross-sectional shapes of the first member and follower member are such as to cause the follower member to rotate with the first member, whislt permitting displacement of the follower transversely of the axis of rotation.

3. An arrangement according to claim 1, in which the first member is a shaft.

4. An arrangement according to claim 3, in which the shaft has at least one flat surface extending parallel to the axis of rotation.

5. An arrangement according to claim 4, in which the shaft has a pair of flat surfaces extending parallel to the axis of rotation and to one another.

6. An arrangement according to claim 3, in which the first member is a camshaft.

7. An arrangement according to claim 6, in which the second member is a valve to be actuated by the camshaft.

8. An arrangement according to claim 7, in which the follower member has a valve-actuating cam profile and contact means which is normally contacted by an operating portion of the valve.

9. An arrangement according to claim 8, in which the contact means comprises a pair of contact rings projecting from the follower member on axially opposite sides of the cam profile.

10. An arrangement according to claim 8, in which contact between the contact means of the follower member and the valve is established via roller means.

11. An arrangement according to claim 1, in which the reference point is the point of contact between a fixed reference roller and the follower member.