Film-thrusting cassette

In a film cassette, a film spool comprising (a) a spool core supported for rotation in a film unwinding direction to thrust a leader section of a film roll coiled about said spool core to the exterior of said cassette and in a film winding direction to return said leader to the interior of the cassette, and (b) a pair of flanges positioned along said spool core to overlie opposite sides of said film roll to radially confine the film roll within skirted peripheries of said flanges and having respective central openings through which the spool core coaxially extends to normally permit the flanges and the spool core to be independently rotated in the film unwinding and film winding directions, is characterized in that:

• engagement means is rotatably fixed to said spool core for initial rotation with the spool core relative to said flanges in the film unwinding direction, for movement into engagement with one of the flanges to make said one flange rotate in unity with the spool core when the spool core is rotated further in the unwinding direction, to improve the ability of said film spool to thrust said leader from said cassette, and in the film winding direction, for movement out of engagement with the on flange to permit the one flange to be independently rotated when the spool core is rotated further in the winding direction, to substantially ensure the leader can be rewound within said skirted periphery of the one flange;
• said one flange has a plurality of concentric arcuate slots cut in it to longitudinally extend in the film unwinding and winding directions;
• and
• said engagement means includes respective hook-like members normally located in said concentric slots for movement along the slots into engagement with said one flange responsive to rotation of said spool core relative to the one flange in the unwinding direction and for movement along the slots out of engagement with the one flange responsive to rotation of the spool core relative to the one flange in the winding direction.