Quick-change collet chuck

A quick-release collet chuck for an automatic capping machine, comprising:

• a shaft 103 for connection at one end to an existing drive of the capping machine, said shaft having a lengthwise through-bore and a lateral through-bore at an opposing end;
• a pin 105 for insertion in the lateral through bore of said shaft;
• a bell cap 102 mounted on said shaft;
• a piston 101 slidably mounted on said shaft beneath said bell cap, said piston having a downwardly extending cylindrical sleeve
• a unitary 22 collet attached to said shaft inside the sleeve of the piston, said collet having an upper mounting collar for attachment to said shaft and a plurality of downwardly extended gripping tines each formed with a ramped bearing surface for engagement by said piston;
• whereby air pressure supplied between said bell cap and piston via the lengthwise through-bore in said shaft urges said piston downward, the sleeve of said piston thereby engaging the ramped bearing surfaces of said gripping tines and closing the tines of said collet to grip a cap.