| 摘要 |
A motorized operator is used for control of a closure, e.g., a garage door operator. Where the garage door is an upward opening door, there are four conditions for operation of the control system, namely stop-down, run-up, stop-up, and run-down. The present operator is one wherein safety conditions prevail, in that the run-down condition may not be established by a simple single closing of a switch because this might be effected carelessly or accidentally. The run-down condition is only established by plural closings of a switch. Gate means are provided within the control system so that the plural actuations of the switch will establish the run-down condition and this may be established only when the door is in the stop-up condition. The plural actuations of the switch must take place within a predetermined time period in order to establish the run-down condition.
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