Patent GB-1007126-A (GB)
Title: Rail vehicle anti-slip apparatus
IPC: B60T8/17
Filed: 1961-12-15
Abstract: 1,007,126. Fluid-pressure brakes. KRAUSSMAFFEI A.G. Dec. 15, 1961 [Dec. 17, 1960; Feb. 25, 1961; April 29, 1961], No. 45044/61. Heading F2F. [Also in Divisions B7 and H2] The circuit of an electrically-controlled pneumatically-operated sanding apparatus for a self-propelled rail vehicle, includes a battery 6, Fig. 1, a switch 3 movable in accordance with the movements of the main driving output control of the vehicle; a switch 5 for the direct manual operation of the sanding apparatus; a forward-and-reverse drive position switch 9 connected to solenoid-operated compressed air valves 12, 13 for supplying air from a reservoir 15 to the sand scattering valves 18 of sand containers 19 adjacent the driven wheels 1, 2; and an electric pulse emitter 22 comprising a direct current generator 23 having its armature terminals connected by a circuit including a condenser 24 and the winding 25 of a polarized relay 26 adjustable by a variable resistance 27 the pulse emitter being responsive to sudden irregular variations of generator voltage which occur when the wheels tend to spin. The contacts 28, 29 and armature 30 of the relay 26, which armature is movable in response to sudden accelerations or retardations are connected to the winding 31 of a contactor 32 which when operative is placed in parallel, through the agency of the switch 3, with the switch 5. The relay 26 and the contactor 32 constitute first and second amplifier stages respectively, the first stage being highly sensitive and the second being weakly sensitive and highly amplifying. When the contactor is inoperative as shown, a condenser 39 is caused to be charged-up by the battery 6. Providing the switch 3 is in the higher output drive positions, as determined by a sector contact 42, the apparatus will be operated as soon as the wheels tend to spin. When the contactor 32 is operated the switch 5 is short-circuited and the condenser 39 is discharged through the contactor coil 31 in order to delay its release. As shown the circuit may control, independently of or additionally to the sanding device, solenoidoperated valves 54, 55 to operate an anti-spin brake and the main driving motor regulator, respectively. The polarized relay 26 may be replaced by a current transformer and the secondary winding of the latter is connected to an electronic amplifier. In this instance the sand scattering apparatus is operable wholly pneumatically the switches 5 and 9 being replaced by a press key-operated valve and a two-way valve respectively, the press keyoperated valve being by-passed when necessary by a solenoid-operated valve controlled by the pulse-emitter. In another embodiment the polarized relay 26 is replaced by a resistance having in parallel therewith an electronic amplifying pulse generator or a transductor amplifier. Referring to the embodiment of Figs. 4 to 6 in which two railway vehicle bogies 64, 65, Fig. 5, are independently driven by diesel engines 56, 57, each of which drives a change-speed gear 59 connected to the wheel sets 1 and 2 of the bogie, the fuel injector pumps 69 of the engines are controlled by pneumatic apparatus 68, each connected through a twoway relay valve 70 to a press-key valve 3 connected to a reservoir 15. The valve 70 is operable when pronounced wheel spin occurs, by a solenoid 71, connectable by an electric control lead 106 or 107 to the main electric control circuit. The valve 70 normally connects the valve 3 with apparatus 68 through positions A and C but when the solenoid 71 is energized the connections A and B are made and the apparatus 68 is connected to atmosphere through a pressure reducing valve 72, thus causing the engine to slow down. Electric motors instead of the diesel engines 56, 57 may be controlled in an analogous manner. The energizing of the lead 106 or 107 also controls the brakes as shown in Fig. 6. The normal direct or indirect braking is effected in known manner through a conduit 74, non-return valves 79 and the brake cylinders 73. However, when the lead 106 or 107 is energized a solenoidoperable valve 75 connects the air reservoir 15 to the cylinder 73 through a pressure reducing valve 76 and non-return valve 78, thus applying a light braking. Referring to Fig. 4, each bogie is directly coupled to a pulse emitter 22 the armatures 23 of which are connected in parallel and to a comparison apparatus 89. The polarized relays 26 and contactors 32 are arranged as before but the switch 5 and the forward-and-reverse drive switch are each double-poled. The comparison apparatus 89 has two slow-to-operate coils 91, 92 connected in the circuit of the armatures 23 and controlled by a voltage-divider 93, 95. Under normal conditions with all wheels gripping the rails 21, the armature 96 of the comparison apparatus is as shown since no current flows in the coils 91, 92. Should, for example, the left hand generator 23 suddenly speed up due to wheel slip the left-hand bogie wheels 1, 2 will be sanded and slip prevented. However, if the sand supply fails, e.g. is frozen, spinning actually occurs and operates the left-hand coil 92 whereby the coil 99 of a contactor 101 is operated to positively disconnect the left-hand relay 26 from the battery and make contacts 103, 105 to energize the lead 106 whereby the brake and/or driving motor of the left-hand bogie 64 are operated as described earlier. According to a modification described with reference to Fig. 7 (not shown) one polarized relay 26 and one contact 32 may control both bogies. In a further embodiment described with reference to Fig. 8 (not shown) both pulse generators are separately excited and connected in parallel, the excitation windings being energized through a voltagedivider and in this instance the comparison apparatus includes a pole-reversing switch. In this embodiment the electrical circuit also provides a guard against wheel-locking by the brakes as described with reference to Fig. 9 (not shown). The embodiment of Fig. 8 (not shown) may be further modified to halve the number of contactors 32, 101 and the number of air valvecontrol solenoids, as described with reference to Fig. 10 (not shown).