METHOD OF AND DEVICE FOR OPERATION OF LIFT DOOR Russian patent published in 1999 - IPC

FIELD: mechanical engineering; lifts. SUBSTANCE: linear motor operates in response to control signal to counteract torque cause by variable length arm relative to door gravity center by changing value of linear force applied to door and acting on constant length arm relative to indicated gravity center. Thus counteracting torque is built and counteraction to torque caused by normal force is provided. First and second torques can be regulated to provide decrease and increase in torque linearly when the door is moving. Velocity profile changes according to curve similar to part of ellipse at side of larger axis. Normal force can be built to somewhat raise the door and thus decrease gravity force acting onto door rollers. Regulation can be done according to open or closed cycle. EFFECT: provision of control of lift door with linear motor with undesirable torques reduced to minimum. 16 cl, 19 dwg