GB913006A - Improvements relating to vehicle speedometers - Google Patents

Abstract

913,006. Indicating-apparatus; speedometers. DAIMLER-BENZ A.G. Oct. 27, 1960 [Oct. 28, 1959], No. 36953/60. Classes 106 (3) and 106 (4). [Also in Group XXXI] A vehicle speedometer comprises a narrow guide 21 fixedly mountable upon a windscreen 20 for guiding a rectilinearly movable indicator mark driven in accordance with speed by a drum 23 invisibly mounted in the frame 22 of the windscreen 20. The drum 23 is driven through a flexible shaft 25 by the vehicle if desired in parallel or serial connection with a normal tachometer. The drum 23 drives an endless band 24 guided at the top over a roller 26 mounted in the guide 21 which may be extended at the top so that the roller 26 may be hidden by the windscreen frame. The guide 21 may be a slotted tubular frame, Fig. 3, the two edges 28 of the slot 29 forming the sides of an indicator window through which the band 24 is viewed. The guide 21 may be a strip with a flange overlapping only one edge of the band 24. A scale may be marked on one or both edges, which may be stepped to indicate through a wider window when particular values are exceeded, Fig. 4. The indicator mark may be a conspicuous horizontal line 30 separating a neutral field of the band from an indicating field 32 contrasting with the neutral field which may be transparent or may match the scale background colour. The indicating field 32 may have longitudinal stripes of, say, green, orange and red of widths corresponding with the steps, Fig. 5 (not shown). With suitable guide rollers the two flights 24<SP>1</SP>, 24<SP>11</SP> of the band 24, may appear side-by-side, one flight carrying the indicator mark and the other the scale. The band may be transparent and the mark and scale coloured or non-transparent. The two flights of a transparent band may lie one directly in front of the other, the indicating field of the front flight progressively covering the scale on the other as the speed increases, Fig. 8 (not shown). In a modification, Fig. 9, the guide 21 is replaced by a transparent support 37, fastened to the windscreen, and carrying a tube 38 of narrow bore whose cross-section is circular at c, rectangular at b and a, as shown in Fig. 10, but is of constant area. A coloured liquid is pressed by a piston of a pressure cylinder from below into the tube 38, the piston being moved in accordance with speed. Reference has been directed by the Comptroller to Specifications 832,375 and 844,575.