Patent GB-301338-A (GB)
Abstract: 301,338. Eccles, W., Perry, J. F., Davison, J. W., and Metropolitan- Vickers Electrical Co., Ltd. July 18, 1927. Electric governors; transmitting mechanism; fluid relays.-In a braking arrangement, particularly for winding-gear, the operation is initiated by a selecting device, e.g. a hand lever, and thereafter controlled continuously by a governor to maintain the deceleration substantially constant at the selected value. In a simple form, the apparatus comprises a fluid pressure braking engine 13 and a control valve 20, operated by a lever 28 controlled by a manually operable lever 36 and a fluid pressure relay 30 controlled by an inertia governor 50 driven from the winding gear 1, so that the brake pressure may be automatically regulated to maintain a predetermined deceleration. The governor 50 is arranged to control a valve 51 for regulating through pipes 31, 32, the relay 30 governing the brake engine valve 20. A pressure reaction lever 52 is provided between the piston rod of the relay 30 and a sleeve in the governor valve 51 so that the relay takes up a definite position for every position of the governor and the brake engine valve floats betwen brake applying and releasing position. An inertia governor is described which is the same as that described in Specification 298,691. In Fig. 3, an inertia governor 211, which is described and is the same as that described in Specification 301,525 is driven by gearing 405, 406 from the winding drum, and controls a fluid relay 215 actuating a brake engine valve 214, which controls the brake engine 206. The relay 215 operates a piston in the valve 214 by a universal joint and a spindle 248 which is connected by a lever 250 to a sleeve in the governor 211. The control handle 256 is connected to a sleeve 508 of the valve 214. Operation of the handle to move the sleeve 508 downwardly connects ports 244, 227 to supply pressure fluid to the brake engine. The consequent deceleration causes the governor to release the pressure below the piston, 515, Fig. 5, of the relay which with the piston valve 504 in the sleeve 508 is forced down by a spring 520 to cut off the fluid supply and also to move a sleeve valve in the governor by means of the lever 250 so as to close the port exhausting the relay and hold the latter in a position corresponding to the position of the governor. If the valve 504 moves so far as to open port 244 to the exhaust port 236, the brakes are released, the deceleration reduced and pressure fluid is supplied by the governor to the relay which raises the valve 504 and the supply to the relay is cut off by the lever 250 and the sleeve in the governor. To prevent hunting, the moving member 251a of a device 252, Fig. 4, carries the pivot 251 of the lever 250. This device comprises a diaphragm chamber 252a connected through a needle valve 255 and a pipe 253 to the brake cylinder at the upper side of the brake piston. A double cantilever spring 251b is arranged between a knife edge 251d on the member 251a and rigidly mounted knife edges 251c and resists downward movement of the pivot 251. The movement of the sleeve in the governor by the lever 250 is thus determined partly by the pressure in the brake cylinder and partly by the pressure in the relay or the position of the relay piston. When the pressure in the brake cylinder tends to vary, the consequent movement of the pivot 251 by the device 252 serves to move the sleeve in the governor in the direction necessary to maintain the pressure constant. A lever 436, acted on by a spring 437 is connected to the lever 250 by a link 436 and ensures that the " back-lash " in the parts is always in the same direction. Electrical inertia governors are shown in one of which the three-phase winding of the rotor of an electric motor is connected to a torque motor having a spring-loaded rotor adapted to operate the brake engine valve. The stator has a threephase alternating current supplied to it or this may be direct current and rotates with the rotor which is driven from the winder drum. When change of speed takes place owing to the inertia of the stator, phase displacement takes place between the stator and the rotor which supplies current to operate the torque motor. In another arrangement, the armature of an electrical machine is driven in accordance with the winder drum and supplies current to drive another machine, the inertia of which when a charge of speed takes place causes a current to circulate in one direction or the other between the machines and through a magnetic device in series therewith which operates the brake engine valve. The magnetic device is provided with a polarizing coil in series with the field windings of the machines. The electrical governor described in Specification 210,923 may be employed. Specification 229,667 also is referred to.