Patent GB-333132-A (GB)
Title: Improvements relating to electric locomotives
IPC: B60L15/20
Filed: 1929-12-09
Abstract: 333,132. Associated Electrical Industries, Ltd., (Assignees oi Whittaker, C. C.). Dec. 7, 1928, [Convention date]. Draw-gear; combined buffer and draw-gear.- In an electric locomotive having g commutator motors 7, Fig. 1, damage to the commutator bars and windings during the starting period owing to excessive localized heating is prevented by providing between the locomotive and train a draw-bar 22, Fig. 3, having an hydraulic escapement or dashpot 21 which allows the locomotive to creep forwards relative to the train, thus effecting a slow rotation of the motor and commutator cylinder 11 and continuously changing the bars with which the brushes 12 make contact. By the provision, as part of the hydraulic escapement, of a regulating valve 48, Fig. 2, the speed at which the motor rotates can be varied to any desired value. In the construction shown the coupling 24 between the locomotive and train is connected to the draw-bar 22 through the medium of a friction draft-gear 32, and the drawbar has associated therewith a liquid.-containing cylinder 33 in which moves a piston 36 associated with a piston rod 37 engaging a connecting-pin 23 on the locomotive frame 2. Passage of liquid from one side of the piston to the other during the starting period takes place through pipes 47, 49, Fig. 2, with the valve 48 interposed, the latter comprising a valve casing 52, Fig. 5, with a conical seat 54, a valve member 55 with a corresponding seat 56, and an adjusting screw for regulating the width of the fluid passage. This arrangement, by -allowing the valve to lift when the flow is reversed, permits an easy transfer of liquid when the piston 36 is being restored to its initial or operative position. In a modified arrangement, Fig. 6, which is employed when the locomotive is adapted for pulling and pushing, two cylinders 71 are arranged at the ends A, B of the locomotive and are connected by two pipe lines 74, 75, the latter having a valve element 76 which regulates the transfer of liquid in either direction. At the end of the stroke of either piston, a collar 80 on one of the draw-bars 72 is arranged to contact with one of two bridge elements 81, 82 so as to break the circuit to the motor, thus preventing the operator from starting the locomotive with the escapement in its inoperative position, the bridges 81, 82 being connected to contact segments 89, 90 on a reversing drum 88 controlled by the operator. Simultaneously, by means of an electrically operated valve 104, compressed air is admitted to the valve casing 76, acting on a piston 101 and effecting a closure of the valve orifice 78, the valve being bye-passed by alternative sets of pipes 110, 111 and 112, 113, so that a pump 96 controlled by an auxiliary motor 97 may quickly transfer the liquid and restore the pistons 73 to their initial operative positions. The current supply to the motor 97 is regulated by an electromagnetic switch 108 which is energized by connection to a contact segment 110 on the main control drum through alternative circuits 125, 126, 128, 132, 136 or 125, 127, 129, 133, 136. During the normal running of the train, i.e., when the main control drum has been moved past the accelerating notches to the running notches, the contact segment 119 also energizes the lead 120 controlling the valve 104, whereby the valve orifice 78 is maintained closed and the pistons 73 in their operative positions.