US 5,191,268 A · Continuously monitored supplemental obstruction detector for garage door operator

Abstract

An automatic door operator with a continuously monitored supplemental obstruction detector. In a first embodiment, the obstruction detector is a radiant beam obstruction detector that transmits a beam of modulated radiant energy across the door opening. A safety signal generator produces an active safety signal only on unobstructed receipt of radiant energy by a receiver. Failure to receive the active safety signal when the motor is closing the door at least stops the door. A two wire cable, which carries both power and the active safety signal, connects the supplemental obstruction detector to the automatic door operator. Constant activation of a portable transmitter or of a local push button can override the supplemental obstruction detector to close the door. An alternative supplemental obstruction detector includes a safety edge having a compressible tube disposed on a leading end of the door. Plural conductors change their conductive state upon compression of the compressible tube. This embodiment may include a delay upon detection of compression of the compressible tube so that contact with the floor is not detected as an obstruction.

Claims25

Dependent claims

In an automatic door operator having a motor coupled for moving a door between an open position and a closed position covering an opening, and a controller controlling operation of the motor corresponding to command signals, the improvement comprising:

a supplemental obstruction detector disposed proximate the opening including
obstruction detection means for detecting when the opening is unobstructed,
a safety signal generator connected to said obstruction detection means for generating an active safety signal upon detection that the opening is unobstructed, and not generating said active safety signal upon failure to detect that the opening is unobstructed, said active safety signal cycling to repetitively cross a predetermined threshold voltage;
and
the controller being connected to said supplemental obstruction detector for at least stopping the motor to stop movement of the door upon failure to receive said active safety signal from said supplemental obstruction detector when the motor is closing the door;
wherein the automatic door operator includes a manually operable push button for entry of said command signals, the controller normally initiating door operation upon momentary operation of the push button during receipt of said active safety signal,
the controller being further operative to close the door upon constant operation of the push button during failure to receive said active safety signal from said supplemental obstruction detector.

4 more elements

a supplemental obstruction detector disposed proximate the opening;
a two wire cable connecting said supplemental obstruction detector to the controller;
the supplemental obstruction detector including
a power receiving means connected to the two wire cable for receiving electric power for operation of the supplemental obstruction detector via the two wire cable,
obstruction detection means for detecting when the opening is unobstructed,
a safety signal generator connected to said obstruction detection means for generating an active safety signal upon detection that the opening is unobstructed, and not generating said active safety signal upon failure to detect that the opening is unobstructed, said active safety signal cycling to repetitively cross a predetermined threshold voltage, and
a safety signal transmitter connected to the safety signal generator and the two wire cable for transmitting the active safety signal via the two wire cable;
and the controller further includes
a power supply means connected to the two wire cable for supplying electric power via the two wire cable, and
a safety signal sensing means connected to the two wire cable for detecting the presence or absence of the active safety signal on the two wire cable by detecting whether the voltage across the two wire cable regularly crosses the threshold voltage;
and
the controller being connected to said supplemental obstruction detector for at least stopping the motor to stop movement of the door upon failure to receive said active safety signal from said supplemental obstruction detector when the motor is closing the door.

9 more elements

Dependencies are inferred from the claim text.

Continuously monitored supplemental obstruction detector for garage door operator

Life of this patent

Continuously monitored supplemental obstruction detector for garage door operator

Life of this patent

Abstract

Claims25