Clutch/brake mechanism

Claim 1

In a web wind-rewind mechanism wherein mechanical energy is alternately coupled to first and second spools between which a web is wound back and forth, the improvement being a direction sensing drive mechanism for alternately coupling mechanical energy to a spool comprising a shaft supported for rotation and for coupling to a mechanical energy source, first and second load pulleys coupled to said first and second spools respectively, journaled for rotation on said shaft, locked against movement along the shaft axis of rotation and having conically shaped flanges sloped toward one another at substantially equal angles relative to said shaft axis, and a commuter wheel mounted over the shaft between the first and second pulleys including a rim having a helical groove mated with a thread member on the shaft for rotating the wheel and moving it along said shaft axis toward the first pulley when the shaft is rotated clockwise and toward the second pulley when rotated counterclockwise and a replaceable rigidly mounted around the rim having first and second conically shaped friction surfaces facing the sloped flanges on said first and second pulleys respectively, sloped at angles relative to said shaft axis equal to or greater than the angle at which an adjacent flange is sloped for enabling a friction surface to drivingly couple rotation of said shaft to a pulley and spool.