Door Operator Having Lock Mechanism

Abstract

A door operator comprises a rotary shaft, a chain disk for rotating the rotary shaft, and a locking mechanism for locking the rotary shaft. The locking mechanism comprises a bidirectional rotary block, a plurality of push pins and anti-rotation posts. When the chain disk rotates, the push pins urge the bidirectional rotary block to rotate the rotary shaft, and when the rotary shaft rotates, the of anti-rotation posts lock the bidirectional rotary block, and preclude the rotary shaft from rotating.

What is claimed is: 
     
         1 . A door operator comprising a chain disk, a rotary shaft, and a locking mechanism, the chain disk being adapted to rotate the rotary shaft, and the locking mechanism being adapted to lock the rotary shaft, the locking mechanism comprising:
 an end disc having an axial hole at a center of the end disc, and a positioning ring at one end face thereof for surrounding the axial hole, the other end face of the end disk being connected to the chain disk;   a hollow outer ring portion having one end positioned in the positioning ring of the end disk, thereby defining a central receiving portion within the outer ring portion, wherein the rotary shaft having one end pivoted in the axial hole and one other end extends beyond the central receiving portion;   a bidirectional rotary block accommodated in the central receiving portion and fixedly connected to the rotary shaft, wherein the bidirectional rotary block comprises a plurality of axial slots and a plurality of radial arc faces, each axial slot and each radial arc ace are arranged in an alternate fashion, one side of each radial arc face intersects with one side of each axial slot adjacent thereto to form a latching angle which is spaced from an inner wall of the outer ring portion by a first distance, a midpoint of each radial arc face is spaced from the inner wall of the outer ring portion by a second distance, and each radial arc face has a radius greater than a radius of the inner wall of the outer ring portion;   a plurality of push pins equidistantly spaced from each other being axially arranged along an inner circumference of the central receiving portion to correspond to the plurality of the axial slots, wherein each of the plurality of push pins has one end secured on the end disk; each axial slot is spaced from the inner wall of the outer ring portion by a third distance, and each push pin has a diameter greater than the first distance and less than the third distance, so that each push pin is slidable on each axial slot and can be locked at the latching angle, and wherein both side edges of each axial slot comprises a fillet each, and each fillet has a radius that is the same as that of the pushing pin;   a plurality of anti-rotation posts arranged in pairs of two, each anti-rotation post has a diameter greater than the first distance and less than the second distance, each pair of the anti-rotation posts is provided on respective radial arc face, a spring is arranged between two anti-rotation posts of each pair to provide a potential energy to the anti-rotation posts so that the posts are slidably moved constantly in the direction of the latching angle; and   a cover plate arranged to rotatably cover the other end of the outer ring portion, and securely connected to the other end of the plurality of push pins by means of a fastener;   wherein, when an external force is applied to rotate the chain disk, the plurality of push pins urge the bidirectional rotary block to rotate the rotary shaft, but when the rotary shaft rotates, the plurality of anti-rotation posts lock the bidirectional rotary block, so as to preclude the rotary shaft from rotating.   
     
     
         2 . The door operator according to  claim 1 , further comprising an outer cover, an output wheel, and a substrate, wherein the outer cover is disposed outside the locking mechanism and having a central shaft hole, one end of the rotary shaft is pivotally disposed at the central shaft hole, and extends through the central shaft hole to connect with the output wheel; and the substrate is connected to the outer cover and the outer ring portion by means of the fastener.