Automatic tension adjusting mechanism for winding and transmitting device for automatic door

摘要

An automatic tension adjusting mechanism for a winding and transmitting device for an automatic door includes a base fixed in a casing; a mount for a transmission wheel around which a belt is wound; the mount being disposed on the base slidably in the right and left directions where the mount forces the belt to be strained and relaxed, and being resiliently energized at all times in one of the directions where the mount forces the belt to be strained; a saw-toothed stop part provided on the mount and adapted to extend in the right and left directions; and an engagement piece provided on the base and adapted to be moved between an engagement starting position with the stop part and a disconnection position from the stop part; a spring between the base and the engagement piece for energizing the engagement piece in a direction where the engagement piece is engaged with the stop part; a tapped hole made in one of the members of the base and the mount; and a bolt screwed into the tapped hole. Two locking states are made selectable: one is a first locking state wherein the bolt is tightened, whereby the engagement piece is fixed at the engagement starting position; the other is a second locking state wherein the engagement piece is fixed at the disconnection part. The bolt is loosened to set the engagement piece to an unlocked state, whereby the engagement piece is resiliently engaged with the stop part.