GB690518A - Calculating apparatus - Google Patents

Abstract

690,518. Calculating-apparatus. WATTIER, L. Feb. 7, 1951 [Feb. 10, 1950; Jan. 17,1951], No. 2996/51. Class 106 (i). Calculating - apparatus for proportionating comprises a quadrant dial 1 bearing a series of equally-spaced lines parallel to one edge and a radius arm 2 pivoted at the centre and having a median line. This median line is graduated, or alternatively the dial bears concentric quadrantal graduations 16. The dial may be rolled to form a cone revolvable in a frame, an arm of which replaces the radius arm. The arm is partly transparent, and carries a cursor 9 having a blind hole 10 to enable it and the arm to be set by a stylus. Cosine and sine or tangent scales 7, 15 and a scale of degrees 14 are engraved around the circumference which also bears an arbitrary cube scale 11 from which corresponding number and square scales 13, 12 are derived. To enable triangles to be resolved, an additional graduated arm, pivoted to a member 16<SP>1</SP> slidable along the edge 4, may be provided, and graduations may be drawn parallel to the edge 4. The member 16<SP>1</SP> may carry a scale of degrees to enable the angular position of the arm to be determined. The quadrant may be secured to, or readily removable from, a base-board mounted at an adjustable inclination or carrying a note-pad, or it may be translucent and mounted above a lamp on a desk. In the conical form, the cone may be incorporated in the support for a table light 39, Fig. 7. On this arrangement, the partcircular scales of Fig. 1 are marked on a horizontal projection 43 of the cone. The cone is rotatable by two-speed setting knobs 41, 42. The cone may alternatively be mounted in a box tangentially to one face of the box on which a transparent scale is formed, the cone being illuminated.