Patent GB-633703-A (GB)
Title: Electronic remote control apparatus for monorail conveyor systems, hoists or the like
Filed: 1946-10-30
Abstract: 633,703. Control systems for electric overhead monorail load-handling plant. DOUGHERTY, C. E., and MINOR, E. E. Oct. 30, 1946, No. 32288. [Class 104 (iii)] In a conveyer system employing electrically driven cargo trucks travelling on an overhead monorail and equipped with hoists, each truck is controlled by a different A.F. carrier, modulated with A.F. "action" signals, transmitted from a central station or a local-control station within block-sections of the rail system. The truck is shunted to appropriate parts of the rail system by manually or electrically operated rail switches. The central-control-station comprises (i) an R.F. transmitter per truck, each of which may be selectively modulated at a number of A.F. frequencies to signal " raise," lower," . forward," " reverse &c. (ii) a block-section transmitter which may be modulated at A.F.'s corresponding to the block-sections I, II, III (iii) a truck-identification-receiver with a number of A.F. filters and indicator-relays corresponding to the number of trucks, to receive A.F. signals from the trucks. All the central control equipment is connected through capacitors to trolleywire 13 which is common to all sections of the rail system. The other two trolley wires are divided into block-sections by R.F. impedance bonds 6, 7, 8. The block equipment 14 on receipt of a signal from the wire 13 transmits on rail 12, within its section, at a common blocking frequency. Portable local control equipment described below, powered from the trolley wires may be used in any block-section to signal via wire 11. The truck equipment, Fig. 3 (not shown) comprises (i) a receiver operating at the respective truck carrier frequency connected through a two-way relay contact, normally to the common trolley wire 13. The demodulated receiver output is fed through A.F. filters tuned to the actionsignal frequencies of the control station, to action relays " raise," " lower " &c. (ii) a block-receiver connected to trolley-wire 12, which operates a relay to disconnect the truck-receiver from wire 13, and connect it to wire 11 to receive localcontrol signals. (iii) A truck-identification A.F. oscillator connected to wire 13 over the contacts of a relay connected to the local-control wire 11. The local control equipment, Fig. 4 (not shown), comprises an R.F. transmitter which may be selectively set to any truck carrier frequency and modulated at any action frequency. It can also inject an A.F. signal into the trolley-wire to energize the relays connecting the truck-identification-oscillator and truck-receiver to wire 13, on completion of a local-control-operation. Thus the central-control-station 4 can for example unload cargo from the hatch 2 of a ship 1 by a traversing-hoist 3 and transfer it to a cargotruck on the dockside mono-rail system Fig. 1. The rail switches 5 are set e.g. for block II, the appropriate blocking signal sent and the truck dispatched by central control. On entering blocksection II, the truck-block-receiver gets a signal from the transmitter of block II equipment via trolley-wire 12, and energizes the relay to disconnect the truck-receiver from central-control signals on wire 13, and connect it to a local-control on wire 11. Local-control unloads the truck and sends the A.F. "operation completed" signal to the truck thereby energizing the relays to reconnect the truck-receiver and connect the truck identification-oscillator to wire 13, thereby operating a relay at central control to give notice that the truck is again available.