Patent GB-126028-A (GB)
Title: Improvements in Self Levelling Mountings for Guns, Range Finders and the like.
Filed: 1916-10-30
Abstract: 126,028. Cammell, Laird, & Co., Carter, G. J., and Sutton, E. Oct. 30, 1916. Self-levelling apparatus.-Relates to self-leveling gimbal mountings for guns, range-finders, and other apparatus on ships or other moving structures, and consists (a) of a special construction and arrangement of the gimbal frames and bearings, (b) of special mechanism for producing the angular displacement between the frames, and (c) of special devices for controlling the displacement mechanism. The bearings of the frames are spherical, and the two pivotal axes are inclined to the longitudinal axis of the mounting. The turning of the frames about each pivotal axis, to compensate for the rolling of the ship or other structure, is effected by mechanism operated by a motor and controlled by electro-magnetic means the current of which is in turn controlled bv a switch operated by gravity or by a gyroscope. In Figs. 1<A>, 1<B>, and 1<c> is shown a gun mounting comprising a pedestal C<1>, a supporting-frame C, an inner platform or frame A to which the gun G is mounted, and a connecting-frame B. The connecting-frame B is pivoted to the gun platform A by two spherical bearings 9, to turn about the axis 7, and to the supporting frame C by similar bearings 14, to turn about the axis 10, these two axes 7, 16 being both inclined at an angle of 45 degrees to the axis 8 of the gun. The respective frames are tilted about these two axes by mechanism deriving its motion from a constantly running motor through clutch mechanism operated by levers 37, 37<1>, Figs. 27 and 28. In the construction shown in Fig. 1<A>, the displacing mechanism between the support C and frame B comprises a worm 45 on the support C and a worm sector 47 on the frame B. The worm 45 is driven by an electric motor 28 through gear enclosed in a box 49. The gear comprises two driving clutch members 33, 34, Fig. 18, rotated by the motor in opposite directions, and a driven clutch member 39 keyed to a shaft 32 and capable of being moved by the levers 37, 37<1> into engagement with either of the members 33, 34. The shaft 32 carries a worm 42 which engages a wheel 43 keyed to the shaft 44, on which the worm 45, Fig. 1<A>, is fixed. The levers 37, 37<1> are actuated in the construction shown in Figs. 25-28 by electro-magnets 70 controlled by a mercury switch, Figs. 25 and 26, through a relay switch 66. 69, Fig. 27. The mercury switch comprises a. U-tube 60 having at each end two depending contacts 62 which just touch the surface of the mercury, thus keeping two electro-magnets 65, Fig. 27, in the relay device' energized so that a switch arm 66 is maintained in the central position by springs 68. If the U-tube is tilted, the circuit through one of the coils 65 is broken, the switch arm 66 being then drawn towards the other coil, whereby a contact 69 is operated to close one of the circuits 72 of the clutch operating gear. One of the clutch levers 37, 37<1> is thereby operated and the displacing mechanism is set in motion. Instead of the contacts 62 touching the liquid, they might be arranged just clear of the liquid. In another modification, there is only one contact at each end of the U-tube, the liquid forming part of the circuit through each of the coils 65.