Patent GB-646011-A (GB)
Title: Improvements in or relating to remote control system
IPC: F15B9/07
Filed: 1946-07-29
Abstract: 646,011. Electric follow-up systems. ASKANIA REGULATOR CO. July 29, 1946, No. 22488. Convention date, Jan. 25. [Class 40 (i)] [Also in Group XXIX] In a follow-up system wherein the control member is movable simultaneously in one or two basic directions, e.g. rotations about two perpendicular axes, and independent power sources drive the controlled member in the respective basic directions, one of the power sources operates at substantially full rate during any lack of correspondence in the one basic direction, while for the other basic direction the respective power source operates at a rate proportional to the deviation from correspondence for deviations up to a predetermined small value, and thereafter at full rate. As shown, Fig. 1, the controlled member 10, e.g. the beam of a crane for charging and discharging a furnace is rockable about the pivot 12 on the shaft 11 by the power source 15 and is also rotatable with the shaft 11 by a power source 14 the two power sources being controlled through respective Selsyn systems from the transmitter MS. Transmitter, Fig. 2. Movement of the radial control arm 13 from side to side rocks the shaft 18 against a spring 23 biassing it to a terminal position, and drives a Selsyn transmitter 35 correspondingly. Stops 22 coacting with a crank-arm 21 limit the shaft movement. Movement of the control arm 13 up and down rocks, through a slotted crank arm 28, a shaft 24, spring biassed to a central position, to drive a Selsyn transmitter 36. The arm 13 may of course be moved so as to drive both Selsyns simultaneously. First receiver, Fig. 4. The Selsyn receiver 38, driven by the transmitter 35, operates through a pinion, rack and links 65, 66 to direct a fluid jet from a pivotal supply pipe 54 into one or other of orifices 55, thereby moving a spring-biassed piston 58 in one or the other direction, to operate a piston valve 60 to admit pressure fluid to the appropriate end of the hydraulic motor 47. The motor 47, through the link 48 and shaft 11, Fig. 1, drives the controlled member 10 in the respective basic direction and at the same time through the link 65 returns the jet pipe 54 to the neutral position as the controlled member 10 reaches correspondence, when the valve 60 is returned by its spring to the cut-off position. With this arrangement the motor 47 operates at maximum power for any deviation from correspondence. Second receiver, Fig. 3. The Selsyn receiver 40, driven by the transmitter 36, Fig. 2, rocks, through a link 91 pivoted to a slidable bar 93, a pipe 78, the fluid jet from which is thereby directed into one of the pipes 80 to move a controller piston' 82 in the corresponding direction. The piston through the link-gear 83, 86, 87 operates a known hydraulic motor 70 which drives the controlled member 10 through worm-gearing in the follow-up direction. The output shaft of the hydraulic system is arranged to rock through motion reducer 106, link-work 105, 104, gearing 103, 102 and arm 101 a further link 92 pivoted to the slide 93, the link 92 at its other end being linked to a lever 111 fulcrumed at 112 and connected to link 114. For all movements of the control arm 13, Fig. 1, and hence of link 91 the resultant movement of the link 92 by both the link 114 and the arm 101 restores the jet pipe 78 to neutral, after a certain amount of hunting thereof necessary to bring the piston 82 to neutral. For small movements the restoring action of the lever 111 predominates and is sufficient to stop the piston 82 before it reaches the end of its cylinder, the rate of operation of the hydraulic motor 70 being in this case proportional to the deviation from correspondence. For greater deviations the piston 82 reaches its cylinder end without the consequential movement of the link 111 being sufficient to move the jet pipe back to neutral, so that the motor 70 operates at maximum rate until the jet pipe is moved by movement of link 92 back to and beyond neutral after which the rate of motor operation is progressively reduced until correspondence is achieved.