Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
Continuously monitored supplemental obstruction detector for garage door operator










Image Number 4 for United States Patent #5191268.

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.








 
 
  Recently Added Patents
Content protection apparatus and content encryption and decryption apparatus using white-box encryption table
Method for transmitting a signal from a transmitter to a receiver in a power line communication network, transmitter, receiver, power line communication modem and power line communication syst
Vacuum cleaner filter adapter ring
Replacing memory pointers with implicit pointers to be used in compiler-generated debug output
Image forming apparatus forming images in response to image formation request from operation unit or external device
Recording apparatus, recording method, reproducing apparatus, reproducing method, program, and recording/producing apparatus
Bias voltage generating circuit and switching power supply thereof
  Randomly Featured Patents
Inductive position sensor with a cursor and a coupling scale
Non-stick coating system with two thin undercoats, the first being polysiloxane
Acid dip for zinc-manganese alloy electrodeposition
Processes for making [R]-ethyl 4-cyano-3 hydroxybutyric acid
Temperature control system for electrical cord reel
Extended life doctor blade and method of forming the same
Ink formulations, print systems, and methods thereof
Charged particle beam system having multiple user-selectable operating modes
Tail for attaching the trailing edge of one roll of tape to the leading edge of another roll of tape and method of using same
Image-driving method and driving circuit of display and display apparatus