US Patent 9850685 Lock drive assemblies

An illustrative motor drive assembly is configured for use in a lockset comprising a case, a longitudinally movable link, and a catch configured to move among a locking position and an unlocking position in response to longitudinal movement of the link. The illustrative motor drive assembly includes a longitudinally extending shaft comprising a worm, a motor operable to rotate the shaft, a driver engaged with the worm, and a longitudinally extending spring. The spring is not directly engaged with the worm, and includes a first end coupled with the driver and a second end connectable with the link. Engagement between the worm and driver is configured to longitudinally move the driver in response to rotation of the shaft.