GB1295307A - - Google Patents

Abstract

1295307 Digital calculators H J HUBINGER and D G HOFF 14 April 1970 [14 April 1969] 17801/70 Headings G4A and G4H A desk-top computer, which may be used for preparing estimates for bids for engineering contracts, receives certain of its input data from probes which are run over a drawing to provide signals indicative of the number of items, or of the length or the area of an item. The computer includes a visual display indicating the magnitude of the parameter determined. A first probe provides a pulse whenever it is pressed on to the drawing, enabling the computer to count the number of items. A second probe includes a wheel which is run along lines whose length is to be determined. Equi-spaced holes at its periphery are sensed by a lightsensitive unit, the number of pulses emitted being proportional to the length. Both these probes may include means (not described) for marking the drawing on contact. A third probe is a planimeter giving a number of pulses representing the area traced. In use, a key on the computer keyboard selects the required probe. A factor dependent on the scale of the drawing is keyed in. The factor may be fractional. The position of the decimal point relative to the display is also set up. The pulses from the probe are now added or subtracted, as selected by a key, to the content, if any, of an accumulator, the total being displayed. To store the count in the accumulator the address of the store is keyed in and displayed, the accumulator count passing to a register. When the store key is now operated the count in the register passes to the selected store. A count can be recalled from a store, and displayed by keying in the relevant address and pressing a Recall button. A count in the accumulator can be added to or subtracted from the count in a selected store. The counts in two stores can be added or subtracted, the result appearing in the accumulator and being displayed. Division and multiplication (e.g. item cost x number of items) are performed by recalling the count from the relevant store and keying in an appropriate factor. Volume may be calculated using a stored programme which determines the average of two areas and multiplies the result with the distance between them. The computer may be used for other calculations by direct entry of data via the keyboard. Further registers are provided for such calculations.