| 摘要 |
Garage door opener for simple installation and to fully actuate various counterbalanced doors of different makes with minimum mechanism, and to be packaged and sold as a compact kit. The opener is built around a short main drive shaft adapted to be coupled coaxially to the end of the door counterbalance shaft. The drive shaft is journalled in two frame side members and therebetween carries a worm gear and two friction drive disks spring-pressed against the gear to transmit limited drive torque therefrom to the shaft. The gear is driven by a worm on the shaft of a motor on a carrier which is slidable on the frame. A manual cam moves the carrier between a worm-engaged position for drive and a worm-disengaged position to release the door for manual operation. A threaded extension of the main shaft carries a pair of traveling nuts which actuate switches to limit door travel both directions. In one modification, the assembly is mounted on studs on a mounting plate and adjusted thereto to bring the drive shaft coaxial with the counterbalance shaft, and the two shafts are coupled. In a second modification, the assembly is cantilevered by its drive shaft on the counterbalance shaft and is stabilized in coaxial relation therewith by a torque-reaction bracket. Such bracket may include a torque-limiting switch operable to reverse the drive in response to excess torque. For most installations, a down-drive cable is added to the counter-balance mechanism and connected to positively move the door from open to closed position in response to down-drive rotation of the counterbalance shaft.
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