Patent GB-959802-A (GB)
Title: Improvements in or relating to a door operator
IPC: E05F15/00
Filed: 1961-05-31
Abstract: 959,802. Control of D.C. motors. VAPOR CORPORATION. May 31, 1961 [Oct. 19, I960], No. 19712/61. Heading H2J. [Also in Division E2] A door operator (Figs. 3, 5) comprises an electric motor 10 connected to the door 32 for opening and closing the latter, a door locking pawl 44 movable by the door from an inoperative to an operative position as the door approaches a given (preferably the closed) position, a spring biased lever 64 arranged to be released by a catch 90 as the pawl is moved to the operative position so as to move to a pawl-securing position, thereby to look the door, and manually operable means, preferably including a solenoid 78, for moving the lever out of the pawlsecuring position to free the pawl, the lever being operatively connected to a control device for the electric motor and to means, e.g. an indicator light or audible signal, capable of indicating whether the door is in the given position in such a manner that actuation of the control device is dependent upon the pawl being free and actuation of the indicating means is dependent upon the pawl being secured. The control circuit (Fig. 9) includes a pair of switches 106, 108 actuated by cams 102, 104, respectively (Fig. 4, not shown) on the drive shaft 14 and arranged so that the switch 106 is normally closed but is opened when the door is very close to its fully open position and the switch 108 is normally open but is closed when the door approaches its fully open position, e.g. during the last fifth of its travel. The circuit also includes switches 110, 112, 114 responsive to movement of the lever 64 and arranged so that when the lever is in its securing position switch 110 is closed and switches 112, 114 are open, when the lever has been turned by solenoid 78, switch 110 is open and switches 112, 114 are closed, and when the lever is held by the catch 90 switches 110, 112 are open and switch 114 is closed. Fig. 9 shows the condition of the circuit when the door is closed and locked. To open the door a manual control switch 142 is closed, thereby energizing an electromagnet 162 which closes switches 164 and 166. The closing of switch 166 energizes electromagnet 176 which closes switch 178, thereby energizing electromagnet 156 which opens switches 148 and 154 and closes switches 150 and 152, and the closing of switch 164 energizes electromagnet 168 which closes switch 170 and thereby energizes the solenoid 78 to move the lever 64 to release the pawl. Simultaneously the opening of switch 110 de-energizes the electromagnet 172 which permits switch 174 to open and thereby extinguishes an indicator light 132, and the closing of switch 112 completes the circuits through the motor field 136 and armature 134 and causes the motor to rotate in the door-opening direction. As the door approaches its fully open position switch 108 is first closed and places a resistance 160 in shunt across the motor armature 134 to provide a braking action and switch 106 is then opened to de-energize the solenoid 78 which releases the lever 64. The lever falls back against the catch 90 and switch 112 opens to break the circuit to the motor, and the door remains in its open position. To close the door the control switch 142 is opened to de-energize the electromagnet 162 and open switches 164 and 166. The opening of switch 164 de-energizes the electromagnet 168 and opens switch 170, thereby ensuring that the solenoid 78 remains de-energized throughout the door closing movement, and the opening of switch 166 de-energizes the electromagnet 176 and opens switch 178, thereby de-energizing the electromagnet 156, closing switches 148 and 154, and opening switches 150, 152. The closing of switches 148 and 154 completes the circuits through the motor field 136 and armature 134 via the switch 114, but the path of the current through the armature will be the reverse of that previously supplied so that the motor will turn in the door closing direction. Resistance 158 provides for slow closing movement. When the door reaches its fully closed position the catch 90 is released and the lever 64 returns to its securing position, thereby opening switch 114, to de-energize the motor, and closing switch 110 which energizes the electromagnet 172 and switches on the indicator light 132.