Patent GB-404275-A (GB)
Title: Improvements in and connected with elevator systems, conveyor systems, or the like
IPC: B66B11/00
Filed: 1932-07-02
Abstract: 404,275. Endless chain elevators. MORRIS, Ltd., H., Empress Works, and HICKLING, H. R., 90, Forest Road, both in Loughborough. July 2, 1932, No. 18740. [Class 78 (i).] In an elevator or conveyer system, means to prevent the accumulation of loads at a discharge station comprise a set of switches corresponding in number to the number of the discharge stations, each of the switches being adapted to be opened when a load arrives at the station and automatically closed when the load is removed, and a second set of switches arranged in a circuit parallel to the first and providing an alternative path, the latter switches being adapted to be normally held closed, but to be opened by the passage of a following or preceding elevator tray or load after a time interval from the arrival of the load at the discharge station which is greater than the average time taken for the discharge of the load so that, when the average time taken for the discharge is exceeded, the motor driving the elevator will be stopped due to both circuits being open together. The first set of switches may be arranged in series with the no-volt release coil of the motor starter or with a separate circuit breaker, or, as shown in Fig. 1 a series of double pole switches 3 may be arranged in the start and stop circuits of a contact starter provided with start and stop contacts 1, 2. The switches 3 are normally closed, but are opened by a load on a platform or grid 4 provided at each station. In parallel with the switches 3 are arranged a number of single pole switches 5. If the load on the platform 4 is not removed before one of the switches 5 is opened, both circuits will be interrupted and the contactor closing coil 6 will release the switch 7, thus opening the power circuit and stopping the motor. The elevator may comprise trays constituted by fingers or arms 9, Fig. 2, mounted on endless chains, the loading and unloading means comprising grids 4 in association with conveyers 10. The grids 4 consist of a series of rollers mounted in frames which are pivotally mounted on shafts 11 and are adapted to occupy either the position shown in full lines or to be raised to the position shown in dotted lines, clear of the elevator path, by a handle 12 and connecting links 13, 14. The switch 3 at each unloading station is located at one side of the elevator structure and is operated by mechanism attached to each grid 4 and comprising one or more fingers, the ends of which project above the surface of the grid ; the fingers are attached to a counter-weighted rotatable shaft provided at one end with a lever which operates the switch when the fingers are depressed by the weight of the load on the grid. A switch 5 is mounted on an upright 19 of the elevator structure adjacent each unloading station, the trays 9 being each provided with a roller or the like 21 adapted to engage an operating finger 20 on the switch. When applied to a conveyer, spaced switches are provided over which the loads pass in turn, the switches being so spaced that one load cannot span and so open two switches, but if the loads back up at the discharge end, both switches are opened and the operating mechanism is stopped.