Patent GB-663913-A (GB)
Title: Improvements in or relating to apparatus for providing an output signal in dependence or displacement of a movable controlling member
IPC: G01L27/00
Filed: 1947-03-06
Abstract: 663,913. Electric control systems. SPERRY GYROSCOPE CO., Inc. March 6, 1947. [March 6, 1946] No. 6390/47. Class 40 (i). A control member e.g. a pressure capsule constrained to have one degree of freedom of motion is releasably coupled for zeroizing purposes to a controlled member flexibly mounted to permit one degree of freedom of motion and prevent other motion thereof, the controlled member actuating a pick-off to produce a signal that measures the displacement from a zero position of the control member. As shown a pressure sensitive element 10 operates through a rod 9 to rock a flexibly mounted intermediate plate lever 40 about its vertical pivot Y-Y<SP>1</SP> the lever rocking correspondingly the armature 61 of an E type pick-off transformer 62. The lever plate 40 is flexibly mounted for limited rocking about the vertical axis Y-Y<SP>1</SP> by upper and lower pairs of springs 43, 44 and 45, 46, the springs of each pair being perpendicular to one another, and their intersecting points defining the axis Y-Y<SP>1</SP>. The lever 40 is similarly coupled to the yoke 60 carrying the armature 61, by parallel springs 47, 48 and a spring 49 perpendicular thereto. The movable element 19 of the pressure sensitive element 10, is rigidly secured to the rod 9 and to a T-shaped plate 20 also flexibly mounted by means of two pairs of crossed springs 23, 7, to a U-shaped plate 16 which is itself pivoted about a horizontal axis by similar crossed strip spring pairs 17, 32 securing the plate to a frame member 15. A bracket member 30 flared out from the plate 16 has the springs 32 secured thereto and carries an adjusting nut 26 whereby the upper and lower halves of the aneroid diaphragm may be made to respond equally to vertical acceleration forces. The rod 9 is adapted to be coupled to the plate lever 40 by a clutch 50 comprising jaws 52 adapted to clutch the rod 9 under the action of a spring 57. The left hand jaw of the clutch comprises a pair of plates rivetted at 54 and pivoted at 55, 55<SP>1</SP> by spring strips 56 to the lever plate 40. When a magnet 75 is de-energised the clutch is disengaged by a bar 71, carried on hinge springs 72, and urged to the left to open the clutch jaws by a spring 74 acting through a lever 76 pivoted at 78<SP>1</SP> to the frame. In this position the lever plate 40 is held centralised by a conical projection 87, Fig. 2, carried on a spring biased arm 67 engaging a similarly shaped recess in an extension 90 of the plate 40. When the magnet 75 is energised the lever 76 is rocked against the spring 74 to move the bar 71 to the right, permitting the clutch to engage under the action of spring 57 just before the bar 71 strikes the pin 88, Fig. 2, to release the lever plate 40 from the centralising device. The armature base 60 of the pick-off transformer is flexibly secured at its rear end to a flexible hinge 70 adjustably secured to the frame Fig. 4 (not shown). The rocking movements of the lever plate 40, thus cause the transformer armature to move substantially parallel to itself. For zeroizing purposes the transformer magnets 621 are adjustable on the framework as at 25<SP>1</SP>, 25<SP>11</SP>. The movements of the lever plate 40 are damped by an eddy-current dash pot arrangement 103, Fig. 3 (not shown). The aneroid device 10 may be made sensitive to speed by means of Pitot tubes, Fig. 5 (not shown). The mechanical transmission described may be used between any input device and any type of pick-off device which may be pneumatic e.g., as in Specification 617,108, [Group XX]. The invention is particularly useful for automatic aircraft pilots. Specification 617,953, [Group XXXV], also is referred to.