Patent GB-158946-A (GB)
Title: Improvements in or relating to gyroscopic apparatus for stabilising ships
IPC: B63B39/04
Filed: 1919-10-15
Abstract: 158,946. Jackson, P. R., (Sperry Gyroscope Co.). Oct. 15, 1919. Gyroscopic apparatus.-In gyroscopic apparatus for stabilizing or rolling ships, the precessionai forces are controlled by means exerting a braking action about the axis of precession, means being also provided for utilizing the energy transferred by the braking means to apply a reverse torque either before or after the change of angular direction and to drive the gyroscope. The braking means consists of a pair of pneumatic cylinders adapted to exert a varying force approximating to the force exerted by the gyroscope. The gyrorotor 4 rotates on a vertical axle 2 in a casing 1 capable of oscillating round the horizontal axis 8. The pneumatic brake cylinders 11, 12 are pivoted on horizontal trunnions 14 carried bv fixed brackets 10 : within the cylinders are pistons 16 having rods 16' pivoted at 13 to the casing 1. Each cylinder carries near its inner end a chamber 20 containing valves 22, 37 and cylinder 35, Figs. 13 and 15. The exhaust valve 22 has, at the outer end of its stem, a roller 24 bearing on the cam surface 25 of a member 26 pivoted to a rod 29 and to a link 30. The rod 29 is pivoted to a fixed abutment 31, Fig. 1, and the link 30 is carried by a shaft 32 extending across the cylinder 11. The shaft 32 is acted on by a tension spring 33, and is also connected by pivoted links to the valve stem 36 and piston-rod 34<1>. The cylinder 35 is adapted to be supplied, through the pipe 41, with compressed air, the flow of which is controlled by a valve 40 operated by an auxiliary gyroscope 42 which is responsive to changes in the direction of rolling of the ship. The operation of these valves is as follows :-Valve 22 is normally held open by spring 33, but should the gyroscope swing to its maximum extent the cam 25 is pulled over rod 29 to close valve 22, thus trapping air in cylinder 11 to exert a braking effect and to accelerate the commencement of the return swing. If the maximum amplitude is not reached, the cam 25 does not function, but piston 34 is depressed at the end of the stroke to rotate shaft 32, thus closing valve 22 and opening valve 37 to admit compressed air to the cylinder through a pipe 39. The valve mechanism at the outer end of each cylinder comprises two valves 44, 45, Figs. 2, 3 and 4, operated by a lever 49 pivoted on a spindle 50. The valve 44 has two seatings 57, 60 and is operated through a lostmotion device 55: when open it allows communication through pipe 100 with a reservoir 56. The valve 45 is operated by a set-screw 63 carried by lever 49 and when open allows communication between the cylinder and the atmosphere through a port 145. The lever 49 is acted upon by a tension spring 48 and is operated by a flexible reservoir 47 connected by a pipe 51, Fig. 1, to the hydraulic device shown in Fig. 9. This comprises two opposed coaxial oil-filled cylinders 70. 71, the pistons 72 of which are connected by a rack-bar 73 gearing with a spur-wheel 74 carried by the trunnion of the gyroscope. The cylinders carry valves 76 connected by a pipe 77; these valves are restricted so that the oil in the cylinder exerts a pressure depending on the speed of precession. The pipe 51 is connected to an aperture 79 in the cylinder. The action of valves 44, 45 is as follows :-When the piston 16 commences its outward stroke the valve 45 is closed by spring 62 owing to the outward movement of the lever 49. As the speed of precession increases, the valve 44 is opened to admit compressed air to the cylinder, and as the speed further increases the valve 44 is closed on to the seat 60 thus trapping the air in the cylinder. Also as the speed increases, an extension 114 of the lever 49 opens a valve 113 to allow the air to escape from the inner end of the cylinder through pipe 41, passage 112 and vent 112'. Means for centralizing the gyroscope may comprise a bar 84 connected to the bar 73 by links 81 and pin 81<1>, the bar 84 bears on the stem 82 of the valve 76 and has a cam surface 84<1> adapted to depress the valve 76 when the limit of precessional oscillation is reached. The resulting increase of valve opening produces a decrease in pressure in the corresponding reservoir 47. Alternative centralizing means comprise electromagnets 91, 92 connected to contacts 87, 88 adapted to be bridged by a strip 90 carried by the trunnion. The electromagnets are adapted to rotate a collar 96 to control the force exerted by the spring 48. The air compressed by the brakes may be used to drive an air turbine 190 or the gyroscope or both pipes 191, 192, being employed to connect the tank 56, turbine 190, and nozzle 193 driving the wheel 6 on the axle 2. In a modification, the supply of air to and from each cylinder is controlled by two coaxial piston valves.