GB870128A - Improved calculating device - Google Patents

Abstract

870,128. Calculating-apparatus. GOODSON, A. E. April 3, 1959 [April 3, 1958], No. 10869/58. Class 106 (1). [Also in Group XV] A calculating device has means for reading corresponding values in two scales of values and comprises a tubular casing having a window and carrying a first scale of values, means for supporting in the casing a plurality of other scales of values which may be selectively viewed through the window and a movable cursor for reading corresponding scale values. As described for currency conversion between British and foreign currencies, a tubular opaque casing 10 has an elongated window 11 and carries a scale 19 graded in pounds sterling adapted to register with a foreign currency scale printed on a paper strip 12 visible through the window 11 and supported by a sleeve 13 rotatably mounted within the casing 10 and having a plurality of recesses for supporting strips with various currency scales. Mounted within the sleeve 13 is a screw 15 rotatable by a knob 14a and having mounted thereon a disclike member 16 carrying projections 17 which engage longitudinal slots 18 in the sleeve 13. The projections 17 bear lines 17a and act as cursors. Rigid with the screw 15 and knob 14a is a cylinder 14 carrying the numbers 0-9 to represent shillings which may be viewed through a second window 21 in the casing 10. A third window 22 in the casing 10 has adjacent thereto a scale 23 representing pence, the number of pence being read off by means of inclined lines 24 on the cylinder 14. In operation, to convert from a foreign to British currency, the knob 14a is rotated to set the cursor line 17a at the required foreign amount, the equivalent in pounds, shillings and pence being indicated by the device. It is necessary to add ten shillings to the number of shillings indicated if the cursor line 17a is more than halfway between two pounds values.