Patent ID: 8371423

Claim:
A braking/clutching device providing a tactile operating sensation free of stick-slip action, the device comprising: a housing having a longitudinal axis; a generally annular armature mounted for movement relative to the housing in a direction generally along the longitudinal axis of the housing; a shaft mounted in the housing for rotation relative to the housing and the armature, and adapted to be rotated around the longitudinal axis by manual operation applied by a human operator; a first set of disks rotationally fixed relative to the housing, but free to move longitudinally with respect to the housing; a second set of disks rotationally fixed relative to the shaft, but free to move longitudinally with respect to the shaft, with the disks of the second set of disks being interleaved between the disks of the first set of disks; and an electro-magnetic coil connected to the housing and configured to selectively generate a magnetic field for moving the armature longitudinally relative to the housing to hold the first and second set of disks in frictional sliding engagement, with the level of force applied for holding the disks together being a function of the strength of the magnetic field generated by the coil; with a flux path of the magnetic field generated by the coil extending from the coil to the armature, from the armature to the housing and from the housing back to the coil, with the flux path of the magnetic field being spaced apart from and not extending through the first and second set of disks; with at least one of the first and second sets of disks presenting a contact surface comprising a bearing material having a relatively low coefficient of friction and a kinetic coefficient of friction that is substantially the same as its static coefficient of friction; and with the braking/clutching device providing a tactile sensation free of stick-slip action when the sets of disks are held in frictional sliding engagement and the shaft is rotated within the housing away from a first stationary annular position to second stationary annular position spaced from the first.