Clamp calibration apparatus and method

A method for calibration of a clamping device having two cooperating grip arms for clamping a workpiece, at least one of which grip arms is movable relative to the other one, the method comprising the steps of:

• contacting a first movable grip arm but not the other cooperating grip aim of the clamping device on a contact member;
• indexing the clamping device by moving it incrementally so that the contact member deflects the movable grip arm relative to the other grip arm;
• sensing a succession of settings of the clamping device as the movable grip arm is deflected by the contact member while the clamping device is being indexed using a sensor.
• providing signals representing the succession of settings from the sensor to a monitoring device;
• and
• operating the monitoring device to provide calibration information from the signals provided by the sensor.

Apparatus for calibration of a clamping device on a machine, the clamping device having two cooperating grip arms for clamping a workpiece, one of which grip arms is movable relative to the other grip arm, the apparatus comprising:

• a contact member that is arranged to be contacted by a movable grip arm of the clamping device but not by the other cooperating grip arm;
• a sensor for determining settings of the clamping device,
• said sensor providing signals representing the determined settings;
• a monitoring device for monitoring signals emanating from the sensor;
• and
• an indexing device to move the clamping device relative to the contact member workpiece during calibration, wherein:
• the monitoring device is operative to receive signals from the sensor at various positions of the clamping device relative to the contact member, and to provide an output representative of the determined settings only from the sensor signals, and without reference to measurements derived from another clamping device or from operation of another machine.