CAM NOMENCLATURE

Trace point

A theoretical point on the follower, corresponding to the point of a fictitious knife-edge follower is called trace point. It is used to generate the pitch curve. In the case of a roller follower, the trace point is at the center of the roller.

Pitch curve:

The path generated by the trace point at the follower is rotated about a stationary cam is called pitch curve.

Working curve

The working surface of a cam in contact with the follower is called working curve. For the knife-edge follower of the plate cam, the pitch curve and the working curves coincide. In a close or grooved cam there is an inner profile and an outer working curve

Pitch circle:

A circle from the cam center through the pitch point is called pitch circle. The pitch circle radius is used to calculate a cam of minimum size for a given pressure angle.

Prime circle (reference circle):

The smallest circle from the cam center through the pitch curve is called prime circle.

Base circle:

The smallest circle from the cam center through the cam profile curve is called base circle.

Stroke or throw:

The greatest distance or angle through which the follower moves or rotates is called stroke or throw.