| 摘要 |
1,257,754. Magnetic compasses. C-H. RIVOIR and M. RIVOIR [trading as PREFAG CARL RIVOIR & CO. ]. June 26, 1970 [July 2, 1969], No.31027/70. Heading G1F. To render a liquid-filled magnetic compass more resistant to damage during assembly and transport, in addition to an axially slidable spring- supported fine bearing 7 supporting the pivot pin 6 of the movable system of the compass, a coarse bearing is provided jointly by parts 9, 10 of the movable system and the casing respectively, the weight of the movable system being greater than the spring force on the bearing 7 for spring displacements such that the course bearing parts 9, 10 do not engage, and the spring force being greater than the difference between the weight of the movable system and its buoyancy when the compass is filled with liquid. Thus when the compass is unfilled, e. g. during assembly or transport, the coarse bearing carries the weight of the movable system. An upper bearing 4 stabilizes the pivot pin 6. In Fig. 2, the fine bearing is a jewel 12 and the coarse bearing is formed by frustoconical surfaces 14, 13 on the pivot pin 6 and casing 1 respectively. The fine bearing may comprise a perforated jewel and a cover jewel Fig. 3 (not shown) and may also have radial spring support. |
