Magnetic Z-directional clutch

摘要

Systems and methods are described for providing a magnetic clutch to limit Z-directional motion of a mass (e.g., a carriage for transporting a robotic mechanism in context of a storage library). According to embodiments, the mass is suspended by cabling, and its Z-directional movement is controlled by a Z-drive assembly. The Z-drive assembly includes a drive gear made of a magnetic or conductive material, and the drive gear is in magnetic communication with a biasing magnet. Embodiments configured the biasing magnet with a particular magnetic moment and a position relative to the drive gear, so that the spinning of the drive gear induces magnetic currents that tend to counteract the motion of the gear. For example, in the event of power loss to the Z-drive assembly, magnetic clutching is used to limit or prevent motion of the mass under the force of gravity.

主权项

1. A system comprising:
a structural framework comprising a mass; and a Z-drive assembly coupled with the mass and comprising:
a cable delivery subsystem comprising one or more cables configured to couple the mass with the Z-drive assembly in such a way as to suspend the mass in context of a Z-directional force in the structural framework;a gearing subsystem coupled with the cable delivery subsystem and configured to control Z-directional motion of the mass using a mechanism that has an internal friction force that is insufficient to hold the mass stationary in opposition to the Z-directional force when the gearing subsystem is in an unpowered state; anda magnetic clutch subsystem configured to apply a non-contact magnetic resistive force directly over an air gap to the mechanism of the gearing subsystem in such a way that the magnetic resistive force, when added to the internal friction force, is of at least a sufficient magnitude to hold the mass stationary in opposition to the Z-directional force when the gearing subsystem is in the unpowered state wherein the air gap extends from the magnetic clutch to the mechanism of the gearing subsystem.