Patent GB-296790-A (GB)
Title: Improvements in or relating to gyroscopic compasses
IPC: G01C19/38
Filed: 1928-09-07
Abstract: 296,790. Nederlandsche Technische Handel Maatschappij Giro. Sept. 8, 1927, [Convention date]. Gyroscopic compasses are provided with follow-up devices for following the movements of the gyroscope relatively to the ship about one or both of the principal horizontal axes due to rolling &c. of the ship, in addition to the means for following the relative movements of the gyroscope in azimuth. The compass shown is of the kind described in Specification 193,397, in which the gyroscope system, which is preferably of the kind described in Specification 10440/11, is mounted in a closed spherical container 44 supported by electrically - conducting liquid in a bowl 1 and provided with aconducting surface 43, Fig. 3. Pivoted within the bowl is a gimbal ring 5 within which is pivoted a ring 8 having an upwardlyextending fork 9 in which is rotatably mounted a sleeve 45<1> terminating at its upper end in a pin 10 which passes through slots 17, 18 in two brackets 13, 16 pivoted about axes 11, 12 and 14, 15, at right-angles to each other on the bowl 1, the line 14, 15 being parallel to the longitudinal axis of the ship &c. The bracket 16 is adapted to be turned about its pivots by a motor 20 mounted on the cover 2 of the bowl which is geared to a pinion 29 engaging a toothed sector 30 on the bracket. The motor also operates a transmitter 28 for a distant repeater. The circuit of the motor 20 is controlled by conducting surfuces 21, 22 on a flange of the ring 8 in conjunction with the conducting surface 43, the resistances of the liquid between the surfaces 21, 22 respectively and the surface 43 becoming unequal when the gyroscope system tilts relatively to the ring 8 about the axis 3, 4 due to rolling of the ship. The motor 23 operating the bracket 13 is similarly operated in accordance with the posi. tions of conducting surfaces 24, 25 in relation to the surface 43. Movement of either or both of the brackets imparts movement to the pin 10 and therefore to the ring 8 so that the latter is moved to follow the apparent tilting movements of the gyroscope system about the two principal horizontal axes. The angles of pitching and rolling. may be indicated by pointers on the brackets 13, 16 in conjunction with scales on the bowl 1. For following the apparent movements of the gyroscope system in azimuth a motor 35 carried by the fork 9 is operated in accordance with the positions of conducting surfaces 41, 42 in relation to the surface 43, the surfaces 41, 42 being carried by a fork 45 integral with the sleeve 45<1>. The motor 35 drives a ring 37 integral with the pin 10 and also operates a transmitter 38. The means shown in Fig. 6 may be employed to maintain the axis of the gyroscope horizontal in any latitude. A pendulum &c. 59 pivoted within the container 44 carries at its lower end a contact 60 which, when the axis of the gyroscope deviates from the horizontal, abuts against one of the contacts 61, 62 to complete the circuit of a reversible motor 54. The motor operates a screwed spindle 56 on which is mounted non- rotatably a nut 57, the displacement of which causes the tilt to ba annulled. The pendulum 59 is damped so that its period is long compared to the oscillation period of the compass.