Patent GB-190215764-A (GB)
Title: Improvements in the Control of Electric Lifts.
Inventor: STEVENS JOHN SANDERS
Filed: 1902-07-15
Granted: 1903-07-09
Abstract: 15,764. Stevens, J. S., Major, C. G., Stevens, E. C., and Stevens, P. H. July 15. Motors, controlling.-Relates to means for controlling electric lifts, and comprises two systems of electric control. According to one system, the passenger, having ascertained the position of the cage, presses an up or a down button according as he wishes the cage to go up or down ; according to the other system, the passenger presses a button corresponding to a particular floor, and the movement of the cage and its stoppage at the required floor follow automatically. The winding-engine and internal motor connections are the same as those described in Specification No. 24,567, A.D. 1899. Fig. 3 shows one form of the first or " two button " system. The current is supplied through the usual starting-resistance 5 to the motor, by either an up switch 1 or down switch 2, both of which are actuated by a single solenoid 3, which also serves to take off the brake 21. The core of the solenoid 3 is connected to the switches 1, 2 through a lever 11, which is fulcrumed on one or other of two blocks or bolts 17, 17<a>, operated respectively by up and down solenoids 6, 7. In the cage and at each landing are a pair of switches 8, 9. On closing, say, one of the up switches 8, the solenoid 6 is energized, and closes the switch 18 in the circuit of the solenoid 3. The bolt 17 is at the same time withdrawn, and the lever 11 therefore turns about the other bolt 17<a> and closes the up switch 1. The circuit of the down solenoid 7 passes through a switch 19, which is opened whenever the up solenoid is energized, thus preventing interference. 19<a> is the corresponding switch for the up solenoid. The solenoid 4 for cutting out the starting-resistance 5 is in circuit with both the solenoids 6, 7, but the cutting out of the starting- resistance before the motor is fairly started is prevented by the device shown in Fig. 4. A star cam 4 on any suitable shaft of the winding-gear is adapted to reciprocate a stud 27 between two trip levers 28, 29 engaging one or more pairs of shoulders 30 on opposite sides of the starting- resistance switch bar. The shoulders 30 of each pair are at different heights, and, as the motor comes up to speed, the device allows the switch to rise step by step under the pull of the solenoid 4 in the manner of a clock escapement. To ensure the complete reinsertion of all the starting-resistance before the motor stops, the solenoid 3 has,. in addition to the circuit controlled by the switches 18, 18<a>, a retaining-circuit controlled by a switch 20 connected with the starting-resistance switch bar so as not to open till all the starting- resistance is reinserted. Thus, on opening the switch 8, the motor continues to run, and the switch 19 i.s held open by the engagement of the bolt 17 with the lever 11 until the switch 20 opens. In a modification, the solenoids 6, 7 are omitted, and each of the switches 1, 2 is operated by its own solenoid. Switches equivalent to the switches 19, 19<a> move with the switches 1, 2, and are opened whenever the corresponding solenoids are energized. Each of the switch bars 1, 2 also carries a third. switch through which and a switch similar to 20 the retaining-circuit of the corresponding solenoid is made. Each of the switch bars 1, 2, on rising, turns an elbow lever arranged beneath it. These two levers are coupled together, and one of them is coupled to the brake lever so that the closing of either the up or the down switch takes off the brake. In a second modification, Fig. 8, there are only two solenoids, one 32 for the up switch and the other for the down. The starting-resistance bar 59 is raised against a dash-pot resistance, by either solenoid, through levers 49 and a sliding spring-pressed collar 52. The up-and-down switches 31, 33 have a lost - motion connection with the levers 49., Instead of the retaining-circuits described in connection wi.th the previous forms, bolts 60, 61 are used, which are shot by means of inclines on the bar 59. Similar bolts may also be used in the first modification. In a third modification, the levers 49 and a bar 59 are connected by means of a chain passing round a sheave on the bar 59 and having its ends connected to the levers. In the second or "one button" system, which may be combined with any one of the controlling-devices described above, the following additional devices are used :- In the cage there is a row of button switches, one corresponding to each floor, and connected to either the up or down solenoid circuits, through switches which are automatically connected to one or the other of these circuits in accordance with the position of the cage. At each landing is a single button which, when pressed, actuates the corresponding cage button, switch. The cage is stopped on reaching the desired floor by the engagement of the push which has been depressed with a projection in the well at that floor.