Opening and closing chuck

An opening and closing chuck, characterized by including:

• a chuck body having a first surface for fixing to a support body such as a robot arm, and a second surface opposite to the first surface;
• a pair of cylinder mechanisms having a pair of cylinder holes formed in the chuck body in parallel with each other, and a pair of pistons freely slidable in the cylinder holes, the pair of pistons being moved to a direction opposite to each other by a reaction of fluid pressure;
• a pinion engaging with a rack provided in the pair of pistons, and synchronizing an operation of the pistons by its rotation;
• a guide rail positioned on the center portion of the second surface of the chuck body and extending along a moving direction of the pistons;
• a pair of chuck members arranged so as to be freely movable along the guide rail in a state of riding on the guide rail at a relative position on the second surface, and moving to a direction opposite to each other in association with the pistons;
• a stationary hole formed so as to communicate with the first surface penetrating through the guide rail and the chuck body at a position covered by the chuck members of the guide rail, in order to fix the chuck body to the support body by using a screw;
• and
• a work hole formed so as to be aligned with the stationary hole on a specified moving position of the chuck member at a portion covering the guide rail of the chuck member, in order to attach a screw to the stationary hole via the chuck member.