Abstract: An air-mechanical expanding chuck for supporting a core for winding webs. A cylindrical chuck body defines a chamber which contains a piston with its piston rod extending out of the chamber for insertion into the core. The piston rod forms a tapered arbor at its end. Three gripping elements bear against flat surfaces formed on the tapered arbor. By applying air to one side of the piston, the arbor is moved inboard relative to the core and the gripping elements are thereby expanded to engage the core's interior. The chuck body's inward face is provided with radially extending T-grooves to receive corresponding T-formed outer ends of the gripping elements which are movable radially in the T-grooves. The gripping elements are readily removable from the grooves and replaceable by elements of other sizes for different diameter cores.

Abstract: A self-contained cylindrical expandable mandrel comprising a closed liquid hydraulic system pressurized by the smaller end of a piston, the larger end of which piston is compressed by a gas, such as compressed air from an outside source through a hose connectable to a pneumatic tire-type check valve on the unit. The closed liquid hydraulic system from the smaller end of the piston flexes a plurality of diaphragms directly urging plungers radially outwardly around the cylindrical mandrel for pressing buttons, bars, or leaves against the inside hollow cores of rolls of web or sheet material for positively grabbing these rolls for rotation directly with the shaft connected to the mandrel.