Patent GB-190520951-A (GB)
Title: Improvements in Electric Elevator or Lift Control Systems
Filed: 1905-10-16
Granted: 1906-03-29
Abstract: 20,951. Otis Elevator Co., [Otis Elevator Co.]. Oct. 16. Lifts.-In an electric lift, means are provided for automatically or otherwise bringing the car to rest at any predetermined point independently of the speed, load, or direction of travel. The system is in part the same as that described in Specification No. 24,455, A.D. 1902. Fig. 1 shows the application to a lift for a building with six stories controlled by a hand-switch 160 on the car, which acts in conjunction with a "floor controller" 150, actuated from the motors and constituted by a number of circularlyarranged contacts engaged by fixed brushes. Three positions of the hand-lever 65 are shown for each motion of the cage. The control circuits are fed from a wire 76. In.either of the first positions of the hand-lever, current passes by the wire 74 to four brushes 77. When the cage is at the second, third, fourth, and fifth floors, one of the brushes 77 engages a small contact connected to a contact 111<1>, and current passes by the brush 127 and wire 113 to complete the circuit of the magnet 80 which controls the solenoid 60 operating the successivelyactuated contacts of the resistance 90 of the extra field 70. Also current passes by the wire 75 to the brush 86 (if the lever is moved in the 'up' direction) and thence to the brush 88 and the wire 89 to the 'up' solenoid 130 of the motor. This circuit is broken as the cage arrives at one of the intermediate floors by the engagement of one of the brushes 86, normally in contact with the outer strip 87 with an insulated contact 117. The second position allows the lift to be started after having been stopped by passing the control circuit directly to the 'up' solenoid of the motor by the brush 122. In the third position, a circuit is completed from the contact 71 to brush 103, wire 104, and coil 50. This coil when energized breaks the circuit of the extra field 70 and also of its solenoid 60 at the contacts 58, 61, and short-circuits a portion 35 of the series resistance at the contacts 108, 109. Furthermore, the breaking of the solenoid circuit 60 closes the circuit of the coil 20 controlling the series field 40 and starting-resistance 30 at the contact 98, and, the magnetization of the coil 20 varying with the voltage across the armature terminals, the starting- resistance and the series field are successively shortcircuited, and the motor attains full speed. The lift is stopped by moving the lever 65 into the 'off' position or into the first position, when the cage stops automatically at the next floor by reason of the making or breaking of the circuits in the manner described above. If the lever is left in the full 'on' position, the cage stops automatically at the limits of its travel. This is effected at the upper limit in the following manner : Circuit is broken through the coil 50 by an insulated contact passing into contact with the brush 101. Circuit is made through the wire 113 by the contact 124 passing, beneath the brush 125, while the 'up' solenoid circuit is broken by the contact 117 passing between the brushes 88, 122. The current flowing through the extra field 70 depends upon the short - circuiting of the resistance 90, and the load in the car is arranged to regulate this resistance automatically in a known manner so that a predetermined slow down speed for different loads is obtained. In the push-button system for a lift with four floors shown in Fig. 2, the control circuit passes by the wire 38, contacts 37, 36, wire 34, and the safety push 11, to magnet 45. This magnet has two oppositely-wound coils 201, 47, so that when one coil only is energized the contacts 49, 51 are separated. Current passes through both coils and through contacts 49, 51, 54, 55 to the floor pushes 23 ... 20. If the push 23 is pressed, current passes by wire 26, coil 40, and brushes 122, 124 to the 'down' solenoid 130 of the motor, the floor controller being shown in the position which it occupies when the cage is between the second and third floors. From the coil 130, current passes by the limit switch 112 and the wire 132 to the negative main at 134. The coil 40 acts to transmit current direct from the coil 201 by the contact 51 to the floor switch. The contact at 51 is therefore broken and the landing pushes are open-circuited. The core of the solenoid 130 rises and makes the motor circuit, the brake shoe 63 being raised by a shunt circuit 155. The magnet 50 is connected across the armature between the contact 149 and the point 171, and serves to control the starting-resistance 80 and the series field 93. As its contacts are successively operated, the circuits of the cage and landing push-buttons are broken at the contacts 175, 55 respectively. As the cage reaches the landing, circuits are made along three wires 185 &c. by contacts 8, 7, 6 engaging brushes connected to the wire 121. This causes the magnets 46, 65, 16 to be energized respectively, which results in the series field and starting-resistances being introduced into the motor circuit, the extra field circuit 91 to be closed, and the magnet 70 to be energized, which latter operates the contacts of the resistance 90 in the extra field circuit 91. When the contact 1 moves away from the brush 122, the circuit of the solenoid 130 is broken and the power supply is cut off, causing also the brake shoe 63 to fall. The motor is then short-circuited through the resistance 98, while the coil 97 opens the control circuit at the contact 36. The cage will accordingly stop and the contacts of the control circuit will assume their normal positions. A similar procedure takes place if another of the push-buttons is pressed.