Patent GB-595904-A (GB)
Title: Improvements in or relating to means for limiting travel of vehicles on rails or like tracks
IPC: B61L23/00
Filed: 1945-07-23
Abstract: 595,904. Controlling movement of track-travelling vehicles. FRANCE. L. A. July 23. 1945, No. 18771. [Class 105] The movement of a vehicle along a track such as a travelling overhead crane is controlled by an electric wire alongside the track normally engaged by a current collector on the vehicle whereby an electric control means such as a vehicle-carried relay is energised to permit movement of the vehicle but on approach to another vehicle or to a temporary or fixed danger zone on the track, e.g. a working- party section or an end section, the wire is deflected out of contact with the collector thereby to de-energise the control means and so stop the vehicle. For the intercontrol between vehicles two such trackside wires are used and each vehicle has a separate and distinct deflector member which serves to raise that one wire which is effective on the other vehicle. Each vehicle may have two collectors so that on approach of the vehicles to each other the nearer collectors lose contact with their respective wires thereby to prevent further approach movement but the further collectors remain in contact with their 'respective wires to permit travel away from each other. As shown in Fig. 1 alternate cranes 20 travelling on an overhead track 21 are respectively controlled from trackside wires 38, 39, the left-hand crane having two collectors 36, 37 engaging the wire 38 and having a deflector 40 to raise the other wire 39 which controls the right-hand crane. For the motor 25 of the left-hand crane propulsion current (three-phase) is supplied under the control of a reversing drumcontroller 24 for approach or separation travel and of stick relays 32, 33 energised from the control wire 38. For approach travel the three-phase current is supplied to the motor over contacts of the stick relay 33 which is energised from the trackside wire 38 by collector 37. The stick relay 33 is picked up by the brief engagement of a raised-tip contact 41A when the drumcontroller 24 is moved from stop position to the approach -travel position at which latter position the column of drum seg. ments 26A engage the column of fixed contacts 27, the pick-up circuit being: from trackside wire 38 connected by a link 44 to phase B of the polyphase supply, collector 37, wire 35, winding of relay 33, wire 24A, bottom contact of fixed-contact column 27, raised-tip contact 41A, segment junction wiring to segment 26C and fixedcontact 27C connected (in a manner not shown) to phase C through the collector 23 for the polyphase propulsion current. The contact at raised tip 41A is immediately broken but the relay 33 continues energised since its stick contact 31A and the contact above it now give a connection through wire 24C, drum segments 26E and 26C to the fixed-contact 27C connected as above to phase C. It will be seen that the motor cannot be restarted except by return of the drum-controller to the zero position with subsequent initial movement to pick up the stick relay 33 or 30. On too close approach to the right-hand crane the collector 37 will no longer contact the wire 38 as this willbe rising towards the deflector 40 on the right-hand crane and the motor will be stopped by the consequent dropping of relay 33. The other collector 36 will however still be in contact so that on moving the drum - controller 24 to the position for separation travel the other stick relay 32 will be similarly picked up and maintained energised so that the motor will receive current for separation travel. Fig. 2 shows an arrangement for raising the two trackside wires out of engagement with the vehicle collectors when it is desired to prevent entry into a working party section, such as a quenching pit area of a steel works when obscured by smoke in actual use, either by the crane driver at crane level briefly operating a push-button 54 or by a workman at floor level briefly operating a push-button switch 53 thereby through a stick relay arrangement to energise solenoids 52 at the two ends of the section so : to lift the trackside wires throughout such section; warning lamps 55 are also lit at the two ends of the section. Freeing of the section is effected by briefly operating one of the similarly located release pushbuttons which breaks the stick circuit of the relay arrangement. The trackside wires may be carried by counterweighted levers normally held with the weight uppermost by energised solenoids; failure of solenoid current therefore allows the trackside wires to rise and cause stoppage of crane travel. A mechanical rope or cable-pull arrangement may be used to raise the trackside wires out of engagement. To permit cranes to approach each other for travelling in tandem switches 42 requiring a special key can be closed to cut out the control by the relays 32, 33.