Patent GB-636469-A (GB)
Title: A device for controlling cut-off in steam driven vehicles
IPC: B61C1/04
Filed: 1946-11-22
Abstract: 636,469. Regulating steam engines. RUTHS INTERNATIONAL ACCUMULATORS, Ltd. (Wiener Lokomotivfabrik Akt.-Ges.). Nov. 22, 1946, No. 34726. [Class 122(iv)] [Also in Group XXXI] In a steam driven vehicle, particularly a steam accumulator locomotive, a device for automatically reducing cut-off is adapted to function only after the reverse actuating member of the vehicle has been moved to or towards the position of maximum cut-off by hand to start the vehicle and after the operator has removed his grip from the member and the functioning of the device is dependent upon spring means (Fig. 1), speed (Fig. 5), running distance (Fig. 3), or steam chest pressure (Fig. 10), or upon a combination of spring means, time and steam chest pressure (Fig. 2), spring means and speed of the vehicle (Fig. 4), steam chest pressure and speed of the vehicle (Fig. 12), or time and speed of the vehicle (Fig. 5). The device may be adapted to reduce the cut-off to a value of between 25 and 40 per cent. In the example shown in Fig. 1 the reversing lever 1 is returned from the maximum cut-off positions F80 or R80 (i.e., for forward or reverse drive positions) on the operator releasing his grip by the springs 5, 5<1>, to a position in which a latch 2 of the lever 1 engages teeth 3 on a segment 4 corresponding to an economic cut-off. In a modification shown in Fig; 2 a spring 5 operates a piston 7 in a cylinder 6 and linkage 8, 9, 10 to return the lever 1 to a position of economic cut-off, the action of the spring being controlled by hydraulic retardation, the hydraulic system including a throttle opening 12, a check valve 11 and a valve 13 affected by valve stream pressure so that when the valve stream pressure is high, the cut-off will be reduced slower than when the steam pressure is low. In the example shown in Fig. 3 the reduction of cut-off is controlled by running distance and a gear wheel 15 connected to the vehicle drive meshes with gears 14, 14<1>, either of which engaging the latch 2 of the lever 1 to bring the lever back to a position of a 35 per cent cut-off. In the example shown in Fig. 4 the reduction is dependent upon the speed of the vehicle and spring means. For maximum cut-off the latch 2 is engaged in a notch in either of members 19, 19<1>, which are connected to a vehicle-driven governor 20 so that on the vehicle attaining a predetermined value the members 19, 19<1> are moved to release the latch 2 and the lever 1 is moved to a position of economic cut-off by the springs 5, 5<1> which are preferably retarded by hydraulic dampers. In a modification of this example the withdrawal of the members 19, 19<1> is effected by electromagnetic forces generated in dependence on speed. In the example shown in Fig. 5 the cut-off is reduced by speed-generated forces and is applied to a crank-driven reverse gear. An axially movable reversing rod can be returned to its central position by the action of either of levers 25, 26 bearing against a collar 27, the levers being connected to a piston 24 working in a cylinder 34, a spring 28 urging the piston upwardly. A vehicle-driven fluid pump 29 urges the piston 24 downwardly and thus reduces the cut-off as the speed of the locomotive increases. In a modification a throttling orifice 32 is provided in the hydraulic circuit in order to retard the action of speed-generated forces. In the example shown in Fig. 6 the cut-off is controlled by valve chest pressure so that the cut-off varies directly with the pressure and spring means are provided for urging the lever into an economic cutoff position. For the position of maximum cut-off the latch is engaged in a notch in either of levers 40, 40<1> and the levers are connected to a piston 45 in a cylinder 44 which is connected by a conduit 47 with the valve chest. The lever 1 is urged to a position of economic cut-off by the springs 5, 5<1>. In the example shown in Fig. 10 the cut-off is controlled by steam chest pressure so that up to a steam chest pressure of, say, 2 to 3 atmospheres a high cut-off is maintained from thence up to, say, 12 to 13 atmospheres a low cut-off is maintained and above 12 to 13 atmospheres a high cut-off is maintained. The latch 2 of the lever 1 is engaged with a notch in either of levers 54, 54<1>, which levers are connected by links to a lever 62 the ends of which are connected to spring urged pistons 57, 59 against which steam pressure from the valve chest bears, the springs 60, 61 are arranged to be overcome by pressures on the pistons of 12 to 13 atmospheres and of 2 to 3 atmospheres respectively. The linkage between the levers 54, 54<1> and the pistons can be connected to a hydraulic damper 66. The example shown in Fig. 12 is a modification of that shown in Fig. 5 so that the cutoff is controlled by speed responsive forces from a fluid pump 29 and the steam chest pressure from a relief valve 68 actuated by a diaphragm so that the valve is arranged to open under the action of a predetermined high steam pressure and thus permits the reassertion of a spring 28 to increase the cut-off, movement of the piston 24 operating the lever 1 through linkage 63, 64, 65 and levers 54, 54<1> moving a segment 4 and the latch 2 being engaged in notches in levers 54, 54<1>.