Patent GB-413715-A (GB)
Title: Improvements in or relating to gyroscopic indicators for use with air and other craft
IPC: G01C19/44
Filed: 1933-01-23
Abstract: 413,715. Gyroscopic apparatus. REID, G. H., 15, Gardnor Mansions, Church Row, Hampstead, London. Jan. 23, 1933, Nos. 33161 /32 and 1450/34. [Class 97 (iii).] A gyroscope mounted for three degrees of freedom is capable of operating either as a free gyro or as a gyroscopic turn indicator under control of the user, means being provided for arresting the movement of the gyro about one axis and resiliently restraining the movement about the other. In the form shown in Fig. 1, a gyro 1 spins on bearings 2 in a gimbal 3, pivoting by bearings 4 on the vertical gimbal 5, which carries a graduated dome 14 and pivots in turn on bearings 6, 7 in the casing 8. The spindle 9 integral with gimbal 5 passes through bearing 7 and terminates in a bevelled gear wheel 10 which may be engaged by a gear wheel 11 on an axially slidably shaft 12 with a thumb wheel 13 to adjust the gyro in azimuth. A collar 16, axially slidable on a sleeve 15 surrounding the spindle 9, is movable by means of a push 22 and carries a bracket 17 to which is pivoted at 18 a toothed sector 19 anchored by a " rate of turn " spring 21 and provided with a turn indicating pointer 24. In order to orientate correctly the gyro before engagement of the sector 19 with a toothed sector 23 on the gimbal 3, a catch 34 in the collar 16 is arranged to rock a spring centred trigger 31 connected by a link 30 to a sliding stem 28 with a terminal fork 27 adapted to engage a pin 26 on the gimbal 3 and force the latter into the central position. In a modification, Fig. 3, the gyro spindle 41 is carried in a gimbal 42, borne on bearings 43 by a second gimbal 44 having vertical bearings 45, 46 supporting it in a casing 47. The rotor 40 is driven by air supplied to nozzles 53 through the hollow spindle and branches of the gimbal 44. The " rate of turn " spring 58, which is connected at one end to a lever 56 pivoted in a fork formed by two lugs 55 on the gimbal 42 and at the other end to one arm of a bell crank 59 pivoted to a lug on the gimbal 44, normally lies inoperatively along the axis of the bearings 43 but may be pulled into position for providing a resilient restraint on the gyro by a flexible cord 50 passing through the hollow spindle of the gimbal 44 to a knob 63. In the modification shown in Fig. 6, the gyro spindle 71 is carried by a gimbal 72 with bearings 73, 74 in a second gimbal 75 borne in turn by bearings 76, 77 in the casing 78. Air for driving the gyro is supplied to jets 81 through hollow bearings 76, 73. An index dome 83 viewed through window 84 is fixed on a spindle 82 projecting through bearing 73. The two " rate of turn " springs 100 are connected at one end to the ends of a chain 101 passing round a sprocket 102 on a shaft 103 rotatable by a handle 104 and at the other end to a chain 99 passing round a sprocket 98 on a sleeve 91 rotatably mounted in the casing 78. In order to effect the change over from a free gyro to a turn indicating gyro a spindle 92 carrying a disc 94 and gear wheel 95 and mounted in the sleeve 91 is moved axially inwards by knob 93 until disc 94 contacts with an overlapping disc 106 fixed on the gimbal 75. In this position the gear wheel 95 engages a gear wheel 105 on the gimbal 75 and the knob 93 is turned until the disc 94 is brought opposite a corresponding recess in the disc 106. In moving into position the disc 94 engages a lug 110 on a lever 111 pivoted to the gimbal 75 at 112 and pushes it across the recess thus rocking the lever 111 which engages at the other end a crank arm fixed on the spindle 86 of the gimbal 72 and effects orientation of the latter. In bringing the disc 94 opposite the recess in the disc 106 both gimbals are thus brought into correct orientation and on pushing the disc 94 through the recess a detent is operated to lock the lever 111 and the gear wheel 105 is engaged by a gear wheel 97 on the sleeve 91 whereupon rotation in the bearings 76, 77, is restrained by the springs 100. The handle 104 is operated according as to whether rate of turn or rate of pitch is to be indicated. Means may be provided for concealing an inoperative indicator or mirrors provided for rendering an awkwardly placed indicator visible. According to the first Provisional Specification, the gyro may be centralized by a conical cup or by a set of tangential arms or the end of the gyro spindle may co-operate with an adjustable spring pressed dome, having a central notch or recess. The outer gimbal may be locked by a conical pin. Specification 340,327 is referred to.