Abstract: A vertical reciprocating conveyor having an improved safety mechanism for automatically locking the conveyor at an elevated level. The conveyor comprises a cargo-supporting carriage which is guided for movement between a lower level and an upper level on a supporting structure. A drive mechanism which can take the form of a hydraulic cylinder is operably connected to the carriage and moves the carriage from the lower to the upper level. A locking arrangement having a pair of ramp members and a locking projection is mounted on the supporting structure at the upper level and is movable among a release position, an extended position and a locking position. An actuating assembly including a roller depending from the pivot arm and a catch plate is mounted for movement on the carriage for moving the locking arrangement between the release position and the locking position.

Abstract: A security door construction for a doorway in a loading dock. The door is constructed of open materials, such as expanded metal mesh, and is mounted for movement between a closed and open position on tracks which are located adjacent the sides of the doorway. A safety beam or barrier is connected to the lower portion of the door and extends across the width of the doorway when the door is in the closed position. Fixed supports are mounted on the loading dock in position to be engaged by the ends of the barrier in the event the barrier is subjected to an impact, thereby preventing lateral deflection of the door by the external force and preventing heavy objects from falling through the doorway.