Calculating device

Claim 2

A calculating device of the slide rule type incorporating indices to facilitate the location and utilization of predetermined constants for unit conversions or other mathematical operations, the device having a pair of cooperating logarithmic scale elements capable of sliding with respect to each other, the indices comprising a first set of special index marks each of which is arbitrarily but conveniently located on one of said scale elements, each of said special index marks being identified by a symbol associated with a particular constant, a second set of special index marks located on the other of said scale elements and identified by symbols associated with the above-mentioned constants, each of said second set of special index marks being so positioned that when the special index marks associated with a particular constant on each scale are juxtaposed, an index of the slide rule is set at the numerical value of the constant on the other of said scales.

Claim 3

The calculating device of claim 1 wherein the cooperating scale elements are circular and are coaxially mounted.

Claim 4

The calculating device of claim 2 adapted to carry out unit conversions wherein a unit identification legend is provided on the scale elements adjacent each symbol.

Claim 5

The slide rule of claim 3 wherein the arbitrarily located special index marks are grouped by class of conversions.

Claim 6

The slide rule of claim 4 wherein each of the said cooperating scale elements includes thereon two or more successive logarithmic scales.

Claim 7

A circular slide rule adapted to facilitate unit conversions comprising two disks which are coaxially mounted and slidable with respect to each other, the first of said disks having near its periphery a logarithmic scale with indices dividing the scale into fields wherein identified classes of conversions are performed, there being at least one arbitrarily located conversion index mark on the scale within each of said fields, the said conversion index marks each being identified by a symbol and a unit legend, the second of said disks having a logarithmic scale thereon adjacent to and in cooperative relation with the scale on the first disk, conversion index marks on the second disk corresponding respectively to each of the conversion index marks on the first disk, each conversion index mark on the second disk being identified by the same symbol As the corresponding conversion index mark on the first disk and a unit legend which when taken with the unit legend on the corresponding conversion index mark indicates the conversion which can be performed by each pair of conversion index marks, the location of each conversion index mark on the second disk being such that when corresponding conversion index marks on the cooperating scales are brought into coincidence, an index of one slide rule scale is set at the conversion factor on the other of said scales.

Claim 8

A circular slide rule adapted to facilitate unit conversions comprising two disks which are coaxially mounted and slidable with respect to each other, the first of said disks having near its periphery a logarithmic scale with indices dividing the scale into fields wherein identified classes of conversions are performed, there being at least one arbitrarily located conversion index mark on the scale within each of said fields, the said conversion index marks each being identified by a symbol and a unit legend, the second of said disks having a logarithmic scale thereon adjacent to and in cooperative relation with the scale on the first disk, conversion index marks on the second disk corresponding respectively to each of the conversion index marks on the first disk, each conversion index mark on the second disk being identified by the same symbol As the corresponding conversion index mark on the first disk and a unit legend which when taken with the unit legend on the corresponding conversion index mark indicates the conversion which can be performed by each pair of conversion index marks, the location of each conversion index mark on the second disk being such that when corresponding conversion index marks on the cooperating scales are brought into coincidence, an index of one slide rule scale is set at the conversion factor on the other of said scales.

Claim 9

The circular slide rule of claim 6 wherein the disks are of substantially equal size and the second of said disks is transparent.