Patent ID: 7017714

Claim:
A double-deck elevator capable of adjusting the spacing in the vertical direction between upper and lower cages provided on a cage frame in a vertically movable manner, comprising: a screw shaft rotatably supported by said cage frame and extending in the vertical direction; screw shaft driving unit for rotating said screw shaft in the forward and reverse directions; controllers for controlling the operation of said screw shaft driving units; an upper supporting member which is engaged with an upper screw part of said screw shaft and vertically moved by the rotation of said screw shaft, and which hoists and supports said upper cage via one upper hoist-and-support part disposed on an upper part of said upper cage; a lower supporting member which is engaged with a lower screw part threaded in a direction opposite to that of said upper screw part of said screw shaft and vertically moved by the rotation of said screw shaft, and which hoists and supports said lower cage via one lower hoist-and-support part disposed on an upper part of said lower cage; an upper measuring unit which measures a load on said upper supporting member from said upper hoist-and-support part; and a lower measuring unit which measures a load on said lower supporting member from said lower hoist-and-support part, wherein said controllers control the operation of said screw shaft driving units based on the load value obtained by said upper measuring unit and the load value obtained from said lower measuring unit before adjusting the spacing in the vertical direction between said upper cage and said lower cage so that said screw shaft driving units output a drive torque with a direction and magnitude for canceling the rotational biasing force applied to said screw shaft attributable to the difference in weight between said upper cage and said lower cage.