Workpiece holding device and loading apparatus that uses the workpiece holding device

A loading apparatus comprising:

• a traveling rail;
• an arm that is configured to move with respect to the traveling rail;
• and
• a workpiece holding device provided at an end portion of the arm,
• wherein the workpiece holding device includes:
• a chuck including a chuck body, and a plurality of chuck claws openably supported on the chuck body and configured to hold a holding portion of a workpiece;
• an operation rod configured to drive the plurality of chuck claws for opening and closing with movement of the operation rod;
• and
• a measuring apparatus configured to measure an opening dimension of the plurality of chuck claws based on a movement amount of the operation rod,
• wherein the measuring apparatus includes:
• a sensor configured to detect the movement amount of the operation rod,
• a calculation unit configured to convert the movement amount of the operation rod into the opening dimension of the plurality of chuck claws, and
• a correction unit configured to cause a detection value detected by the sensor to be linearly approximated to make a correction.