Abstract: A capping machine (10) and method for installing a cap (12) having a threaded portion onto a container (14) having a threaded portion, the threaded portion of the cap corresponding to the threaded portion of the container, the capping machine having a rotatable turret (20) and a rotatable cap chuck (16) which grips the cap and positions the cap on the container. The cap chuck is rotated by a spindle (22) driven by a servo motor (24) at adjustable and reversible rotational velocities independent of the rotational velocity of the turret. The number of rotations of the cap is determined by monitoring the number of rotations of the servo motor compared to the number of rotations of the turret and is transmitted to a spindle drive control(70). The torque imparted to the cap is monitored by a torque monitor (50) and is transmitted to the spindle drive control. The rotational velocity of the cap is adjustable in response to the compared monitored number of rotations and monitored torque.

Abstract: A chuck (10) has a jaw bell (20), a lower bell portion (22) surrounding a plurality of jaws (40) and a hub (28) surrounding an upper portion of a jaw stem (60). A second portion of the jaw stem extends beyond a jaw bell hub (28) and is surrounded by a compressed jaw stem spring (76). The jaw stem spring is retained between a bell hub collar (34) and a jaw stem collar (70). The force of the jaw stem spring holds the jaw bell around the jaws, holding the jaws in a closed position. A stripper (80) has an upper end (82) carried within the jaw stem. A stripper spring (90) located above the upper end of the stripper is compressed and surrounded by the jaw stem. The lower end of the stripper has a disk (84) with a frusto-conical cross-section in slidable contact with the jaws. The jaw stem spring exerts more force downward on the jaw bell than the stripper spring exerts downward on the stripper to hold the jaw bell around the jaws and the jaws closed.