GB580195A - Position indicator for vehicles - Google Patents

Abstract

580,195. Position indicators for vehicles. SCOPHONY, Ltd., and GALE, A. J. Aug. 9, 1944, No. 15183. Addition to 580,165. [Class 97 (ii)] In a position indicator according to the parent Specification and in which the extent of the to-and-fro movement produced by the log signals is predetermined by the reading of a magnetic compass, a correction for the magnetic deviation corresponding to the indicated position is fed back to the compass-driven shaft from the latitude and longitude counters. As shown, the magnetic deviation is represented in relief on a cylindrical cam 66, which represents the earth's surface on Mercator's projection. The cam 66 is fixed on the shaft 67 and the latter is rotated by the gears 71, 72 and shaft 72A connected to the longitude counter and is moved axially by the gears 70, 74, 73 and shaft 73A connected to the latitude counter, so as to bring the part of the cam 66 corresponding to the indicated position beneath a cam follower 66A. The shaft 1, shown also in Fig. 1 of the parent application, is driven by spiral gears 60, 61 from the compass-controlled shaft 62. The gear 61 is non-rotatable, but axially movable, on the shaft 62 and is pressed by spring 64 against a bearing 65 carried by the cam follower 66A. Thus the relief on the cam 66 can move the gear 61 axially on the shaft 62 and impart an additional rotation to the shaft 1. The spiral gears 60, 61 may be replaced by an epicyclic gear system. In a modification, the cam follower may be caused to move over the correction cam.