Patent GB-191405214-A (GB)
Title: Improvements in Stabilisers for Aeroplanes.
Inventor: THAW ALEXANDER BLAIR
IPC: B64C17/00
Filed: 1914-02-28
Granted: 1915-03-01
Abstract: 5214. Thaw, A. B. Jan. 14, [Convention date]. Steering and balancing automatically. In a stabilizer for aeroplanes having drums connected to pairs of longitudinal and lateral balancers, each drum is controlled by a pair or swinging 1 e v e r s which, upon deviation of the machine, move relatively to one another and close an electric switch to effect the operation of the drum. The angle of inclination of the machine at which the automatic control becomes operative may be regulated m a n u a l l y without interfering with the automatic action of the device. In the arrangement described, the drums 35, 37, Fig. 3, control the lateral balancers and the drums 36, 38 the fore and aft longitudinal balancers. The drums are normally free on a continuously-driven shaft 30. Each drum has an internally toothed recess 48 engaged by pinions 51 carried on a plate 52. The pinions 51 gear with a pinion 49 fixed to the shaft 30 so that they and the plate 52 rotate about the shaft. The plate 52 is provided with a toothed wheel 53 which is adapted to be engaged by a pin 54, whereby the plate is held against rotation and the drum is driven by the pinions 51. The pin 54 is raised to engage the wheel 53 by an electromagnet, which is energized when the machine tilts. Each of the four electro-magnets corresponding to the four drums 35 ... 38 is controlled by a separate pair of swinging levers 77, 101, Fig. 17, forming a pendulum. The lever 77, pivoted on a shaft 95, is provided with a pendulum bob 100 and connected by a link 78, Figs. 8 and 14, to a bracket 70 on a sliding contact plate comprising two segments 67, 68 fixed together but electrically insulated by a strip 69. The lever 101 is pivoted on a stub axle 102 projecting from an arm 103 of a cradle 99 pivoted on the shaft 95. The cradle is provided with a weighted bar 107, which tends to raise its arm 109 carrying a roller 108 against a stop formed by an adjustable cam 111. The lever 101 is provided with a weighted lower end 105, which tends to urge it in the direction of the arrow a and to bring the roller 112 against the lever 77. The movement of the lever 101 in the direction of the arrow a is limited by a link 82 which is connected to the upper end of the lever 101 and to a bell-crank lever 71, Fig. 14, the foot 106 of which abuts against the segment 68. The links 78, 82 are insulated from the bracket 70 and lever 71. The angle of inclination at which the pendulum device becomes operative is determined by the adjustable cam 111. If the machine inclines to a greater angle, the pendulum rod 77 presses against the roller 112 and moves the lever 101 in the direction of the arrow b. The upper end of the lever 71 is then moved against the bracket 70 and the circuit of the corresponding electro-magnet is closed. The cams 111 are fixed to pulleys 89, Fig. 2, those marked T being controlled by cords 126, 127 connected to the hand-lever for steering vertically and those marked L by cords 124, 12@ connected to the hand-lever for controlling the lateral tilting of the machine. The cords 124, 125 are connected through a spring 128<a> to trip levers 128 pivoted to carriages 119, 122 which are interconnected by cords 121. These carriages are arranged adjacent to carriages 129, 130 connected together by cords 133 and by cords 139, 137 to the drums 37, 35 controlling the lateral balancers. The carriage 119 is secured to a lever 115 connected by a cord 114 to the drums 89 (L). When the cords 124, 125 are pulled, the trip levers 128 on the carriages 119, 122 engage the notch 136 on the carriages 129, 130 and pull on the cords 137, 139 to rotate the drums 35, 37. The carriage 119 also moves the lever 115 controlling cams 111 attached to the drums 89 (L) and sets the automatic apparatus to maintain the desired inclination of the machine. The carriage 129 is free to move to the right under the action of the automatic device, and can move to the left by overcoming the spring 128<a>. The drums 36, 38 and the pulleys 89 (T) controlling the longitudinal balancers are similarly controlled by a lever and system of carriages. In order to prevent the overwinding of the drums 35 ... 38, wipers 143, Fig. 3, are arranged in the circuit of the electro-magnets and bear against the drums, which are provided with an insulating- section to break the circuit of the electro-magnet after the drum has made a complete rotation. The Specification as open to inspection under Section 91 (3) (a) comprises also an automatic speed-controlling device, consisting of a pressureplate 144, Fig. 18 (Cancelled), arranged at rightangles to the direction of flight and urged forwards by a spring 148. The plate is connected to a switch lever 152 which is adapted to close one or other of the circuits of electro-magnets 151, 154 when the speed of the machine, as indicated by the air pressure on the plate, falls below or rises above the desired minimum and maximum speeds. The electro-magnets 151, 154 control the elevators for directing the machine downwards or upwards respectively. This subject-matter does not appear in the Specification as accepted.