摘要 |
<p>A chain guide (14) is provided for the otherwise unsupported upper run of the endless roller chain (10) of a motor-driven garage door operator. With the chain loop in a vertical plane, the chain guide (14) takes the form of a trough (36) having at its bottom an upstanding central ridge (40) which supports the chain (10) by its rollers (42) and with the links (44) clear of contact with the floor and sides of the trough. The chain guide (14) is supported indirectly by the trackage (26) of the door operator, being mounted upon the fixed rail spacer (46) of one form and carried upon the movable trolley (12) of the other.</p> |