Abstract: Theft of a bicycle is discouraged by a locking mechanism in the front headstem that controllably engages the handlebar-attached headstem with the front fork or disengages the headstem and fork for free relative rotation. A shaft attached to the fork and a sleeve attached to the handlebar clamp are connected at a locking junction which is rotatable as a whole in the front journal of the frame. A key operated cam moves a locking roller radially outwardly of the shaft to engage a receptacle in the sleeve for engagement or allows the roller to retract into an aperture for disengagement. The shaft and sleeve have complementary conical tapers axially positioned by a split conical bushing. A cylinder lock operates the cam via a key having a substantially tubular configuration with a uniquely configured axial end for positioning lock pins against axial spring pressure.

Abstract: An automatic derailleur shifter is disclosed which includes a hollow cylinder body and a piston rod movable within the cylinder. The piston rod carries a dual element piston within the cylinder body in a manner to permit substantially unrestricted fluid flow through the piston when the piston rod is moved in a first, upward direction and a greatly restricted fluid flow when the piston rod is moved in the second downward direction. A first, fixed piston element is fabricated of diameter less than the inner diameter of the cylinder to allow unrestricted fluid flow thereabout. A second, movable piston element is provided and below the fixed piston element includes a flared skirt for sliding, sealing engagement between the movable piston element and the cylinder. A small, restricted longitudinal channel is provided through the fixed piston element which terminates at its lower end at a circular channel.