Patent GB-526101-A (GB)
Title: Improvements in or relating to apparatus for repeating the movements of a member such as the movable member of an instrument
IPC: G01C19/40
Filed: 1939-01-06
Abstract: 526,101. Fluid-pressure servomotor-control systems. SMITH & SONS (MOTOR ACCESSORIES), Ltd., S., and MEREDITH, F. W. Jan. 6, 1939, No. 514. [Class 135] In an apparatus for repeating the movements of a member a control deflector moves between a pair of opposed and relatively fixed nozzles to vary the pressure in an outlet conduit. Said conduit has a branch conduit leading to a resiliently loaded pressure responsive device carrying the nozzles adapted to restore their relationship to the deflector. Figs. 1 and 4 show the application of the invention to the control of a rudder servomotor by a directional gyroscope. The outer gimbal ring 41 of the gyroscope is coupled by a link 18 and arm 17 to a control quadrant 15 with an inclined edge adapted to move between opposed nozzles carried by a block 105. Coiled resilient pipes 23, 24 connect one nozzle through a filter with a source of fluid pressure above or below atmopheric pressure and the other with an outlet conduit 38 and a conduit 39 leading through a port 40 to the interior of a metallic bellows 29. The rigid movable end of the bellows is formed with a well housing a bearing plate 33 adapted to receive one end of a strut 34 secured at the other end to the pipes 23, 24 by a clamp 25. The pipes are also clamped to a housing 28 so that they tend to withdraw the nozzles from the baffle. As the control quadrant moves pressure is built-up or reduced in the conduit 38 and bellows 29 to adjust the nozzles to a new position of equlibrium. The conduit 38 leads to a remote spring-loaded bellows 44 adapted to actuate the control valve 47 of a servomotor 50, 51 connected by one end of a rod 52 to the rudder. The other end of the rod 52 is connected by a viscous link 54, spring-loaded lever 55 and link 57 to a movable seat for the control valve 47 to provide a follow-up action. Throttle valves 59, 159 are inserted in the pipes 39 and 38 or the pipes may be constructed whereby the relationship between the movement of the control member and the consequential movement produced by the bellows 44 can be regulated according to requirements. For example during an oscillating movement of the craft movement of the servomotor valve may lead the movement of the control member so that check-helm is applied automatically by the introduction of a component depending on the velocity of deviation without other velocity measuring means. Fig. 6 shows the invention applied to the remote control of a compass card. The outer gimbal ring of a directional gyroscope is secured to a control member 62 having a depending inclined flange 63 working between three pairs of opposed nozzles spaced equally around the flange. These nozzles are carried by coiled resilient pipes 23, 24 coupled to metallic bellows subject to outlet pressure as in the form described above. The pipes 23, 24 are clamped to the top of the bellows housing by clamps 25 carrying adjusting screws 104 whereby the position of the nozzles relative to the control flange may be adjusted. The compass card 80 is carried by a vertical spindle turning on bearings one of which is secured to the glass protecting the card while the other is secured to a base 86. A plate secured to the card has an eccentric hole adapted to receive a tubular member freely surrounding the spindle 81 and fixed to a collar supported by a number of equally spaced resilient rods 96 secured to the base. A collar 95 secured to an intermediate part of the rods 96 is coupled by links 94 to three diaphragms 91. These diaphragms which have a single corrugation and are backed by plates 93 are secured in recesses in a triangular casing by plugs 89 recessed to provide actuating chambers 90 connected by pipes 101, 102 103 with unions 73, 74, 75 leading to the outlet pipes from the three sets of nozzles. In a modification the compass card is turned by three longitudinally arranged bellows acting on a three-armed tiltable plate suspended by the covering glass by a weighted pendulum member and engaging a slot in a member secured to the card.