Mounting assembly for a machine-tool actuator

A spindle assembly comprising:

• inner and outer coaxial shafts having front and rear ends and extending along a common axis, inner shaft being axially displaceable in the outer shaft;
• a holding assembly on the front ends adapted to grip a tool or workpiece in an axially forwardly displaced position of the inner shaft relative to the outer shaft;
• a coupling ring fixed on the rear end of the outer shaft and formed with a plurality of radially outwardly projecting lugs;
• and
• an actuator having a piston axially engageable with the rear end of the inner shaft and operable to axially shift the inner shaft in the outer shaft, the actuator being formed with a radially inwardly open groove and with a plurality of radially inwardly open cutouts through which the lugs are axially movable in a freeing position of the ring relative to the actuator, the ring being rotatable about the axis relative to the actuator from the freeing position into a holding position with the lugs angularly offset from the cutouts and the ring locked axially to the actuator.

A spindle assembly comprising:

• inner and outer coaxial shafts having front and rear ends and extending along a common axis, inner shaft being axially displaceable in the outer shaft;
• a holding assembly on the front ends adapted to grip a tool or workpiece in an axially forwardly displaced position of the inner shaft relative to the outer shaft;
• a coupling ring fixed on the rear end of the outer shaft and formed with a radially outwardly open groove;
• an actuator having a piston axially engageable with the rear end of the inner shaft and operable to axially shift the inner shaft in the outer shaft;
• and
• a plurality of pawls pivotal on the actuator between inner positions engaged in the groove and axially locking the ring to the actuator and outer positions clear of the groove and allowing the ring to be separated axially from the actuator.