Tracer control system

Claim 1

A tracer control system which performs tracer control with variable clamp level by calculating the direction and velocity of tracing through utilization of displacement signals from a tracer head tracing a model surface, said displacement signals being utilized along with a predetermined composite displacement signal for generating normal and tangential velocity components with respect to said model surface for determining said direction and velocity of tracing, said system comprising: an input unit for entering data defining a series of tracing operations, said data including clamp feed data for limiting the motion of said tracer head on a first predetermined axis of said tracer control system to a respective clamp level for each said tracing operation, and said data including data that is identical for each said tracing operation of said series of tracing operations, said identical data selectively including common starting and end points, and feed limits for the two axes of said tracer control system other than said first axis; a memory for storing the data received from the input unit; a processor for selectively reading out the data from the memory and from said data input unit and for controlling each said tracing operation in correspondence therewith; means for detecting the current position of the tracer head according to each said tracer control system axis and for providing data corresponding to said current position to said input unit; a control device including a clamp feed for controlling said clamp level of each said tracing operation according to said clamp feed data to a respective predetermined value for each said tracing operation, and means for switching between said tracing operation to said clamp feed and back to said tracing during each said tracing operation, depending on the value of said normal velocity component.