Abstract: An isolation lock through which a workpiece item can move in a path between first and second regions at different pressures, the lock comprising a housing having an upper item entrance and a lower item exit at opposite sides of the housing, a movable member within the housing defining an item-receiving surface disposed substantially in a plane which lies at a constant acute angle to the horizontal regardless of its position to enable gravity movement of the workpiece over the surface, the member movable to translate the item-receiving surface between upper and lower positions in which, respectively, the uppermost portion of the surface is adjacent the entrance to receive the workpiece and the lowermost portion of the surface is adjacent the exit to deliver the workpiece and means providing an air-tight seal between the exit and the surface when the surface is in its upper position and between the entrance and the surface when the surface is in its lower position.