Patent GB-510697-A (GB)
Title: Improvements in automatic pilots for aircraft
IPC: G01C19/00
Filed: 1937-11-04
Abstract: 510,697. Automatic pilots for aircraft. SPERRY GYROSCOPE CO., Inc. Nov. 4, 1937, No. 30234. Convention date, March 4. Addition to 506,066. [Class 135] The variable loading of the barometric capsule of the parent Specification is replaced by a transmission device arranged so that after a change of external pressure by more than a pre-arranged amount the servomotor is arrested before the external pressure has been restored to its normal value. In the form shown the barometric capsule 52<1> is pivoted at 73 to a lever 72 pivoted in turn to a bracket 74 carried by a bi-metallic strip 75 anchored at 76 to a rigid bar 78 and at 77, 77<1> to a supporting bracket 79. The lever 72 is in two parts 81, 81<1> joined by a spring clamp 82 and is coupled by a link 71 to a pivoted control shutter adapted to co-operate with control ports 62, 62<1>. These ports lead through passages in a valve, operable by a knob 56<1> to throw the barometric control out of operation, and pipes (not shown) to nozzles on the gyroscope. A needle valve on the end of the spindle 84 controls the communication between atmosphere and the interior of the barometric capsule. Adjustable stops are arranged opposite the ends of the link 71 so that a movement of the free end of the capsule of more than a pre-arranged amount in other directions away from normal causes the lever to break joint and so permit the restoration of the control shutter to its mid-position with a less return movement of the barometric capsule than the displacement resulting from the pressure change. Specifications 416,813, [Group XXXIII], and 510,767 are referred to. The Specification as open to inspection under Sect. 91 comprises also the automatic pilot shown in Fig. 5 (Cancelled). A control surface 91 is operated by a power device 90 under the control of a relay valve 92 actuated by a semi-circular baffle 92<1>. A gyrovertical 1 controls a semicircular baffle 7 adapted to co-operate with a pair of slots 8 and 9 coupled by pipes 11, 12 with the two sides of the diaphragm 92<1> to vary the pressure differential acting thereon. The nozzles 8, 9 are caused by a pivoted member 14 coupled by a link 15, crank arm 16, toothed gearing 18, 19 and bevel gearing 20, 21 with one element of a differential gear 23. A follow-up connection from the power device is made to a second element of the differential by cables secured to a pulley 5. A third element of the differential is connected through worm gearing 24 and bevel gearing 25 with an adjusting shaft 28. This shaft may be rotated by a hand knob 13 or by a reversible air turbine 29 supplied with air through nozzles 30, 31. The air supply to these nozzles is controlled by a hinged baffle 63, cooperating with slots 62, 62<1> and actuated by a barometric capsule 52 acting through a bimetallic strip 63<1>. The barometric capsule is loaded by a spring 69 tensioned by a cam on the shaft 28 acting through lever mechanism 68, 68'. A manipulating knob 56 is adapted to move a sliding plate 55 to put the barometric control out of action and connect the barometric capsule to atmosphere. This subject-matter does not appear in the Specification as accepted.