| 摘要 |
<p>A powered garage door opening system is provided for easy installation and service without a skilled installer or repairman. The system includes in combination a trolley assembly comprising a guide rail structure, a trolley unit supported on the guide rail structure for slidable movement lengthwise thereof, drawbar pivotally connected to the trolley unit for connection to a door, chain drive extending for the length of the guide rail structure, having a driving sprocket at one end and an idling sprocket at the other end, the chain drive connected to the trolley unit to slidably move the trolley lengthwise on the guide rail structure, and chain tension responsive device located on the guide rail structure adjacent the driving sprocket having a tab that moves as tension in the chain increases; an operator head assembly comprising a casing containing a motor with speed reduction to a drive shaft, the drive shaft having a threaded section with threaded limit cams thereon to move up or down the shaft dependent upon rotation of the shaft, and limit switches located to be triggered by the cams to indicate open position and closed position of the door, a tension reversing switch located in the casing for contacting with the tab of the chain tension responsive device when the operator head assembly is joined to the trolley assembly, the operator head assembly containing all the electrical circuitry, and connector for joining the trolley assembly and operator head assembly comprising a forked end on the drive shaft of the operator head assembly. adapted to fit into an engaging pin socket connecting directly to the driving sprocket of the chain drive in the trolley assembly, and including bolts to hold the trolley assembly and the operator head assembly in joined relationship.</p> |
