Abstract: A park mechanism for an automotive transmission having an output shaft comprises a rotatable lock ring structure connected to the output shaft, a non-rotatable lock ring structure positioned in proximity to the rotatable lock ring structure, and a pressure mechanism (preferably, including a spring-biased piston within a pressure chamber) responsive to application of pressure thereto for moving the non-rotatable lock ring structure to a disengaged position for non-engagement with the rotatable lock ring structure, and responsive to the release of pressure therefrom for moving the non-rotatable lock ring structure to an engaged position for engagement with the rotatable lock ring structure. Preferably, the rotatable lock ring structure is provided with at least one receptacle or tooth, and the non-rotatable lock ring structure is provided with at least one tooth receivable in the receptacle or tooth.

Abstract: Gate mechanism for a data cartridge library system including an upstanding lever arm having a laterally extending tab formed at its upper end and a generally Z-shaped member extending from its lower end, the distal end segment of the Z-shaped member forming a light-breaking flag disposed between an optical switch. The lever arm is pivotally attached proximate its lower end to a pivot member that allows the lever arm and its appendages to be rotated about orthogonal axes. An actuator is attached to the lower end of the arm so as to rotate it about one of the axes, and a spring is attached to the lower end of the lever arm to return the arm to a neutral position following its rotation about either axis. The gate mechanism is useful in blocking entry to a drive unit, limiting ejection distance of a cartridge ejected from the drive unit, and indicating when a cartridge extends out of the drive unit.