The members of this special exhibit contain scales of hyperbolic trigonometric functions that are used in conjunction with regular trigonometric scales to perform calculations of vector quantities, and were particularly useful in electrical engineering. The first vector slide rule was the K&E Model 4093-3 (and 4093-5), which first appeared in K&E’s 1930 catalog. This model was discontinued and their new vector rule model, the 4083-3 (and 4083-5), was introduced in 1937. Other vector rules from other manufacturers quickly followed K&E’s lead during the subsequent decades.
Details of the use of these scales are provided in the vignette Vector/Hyperbolic Calculations. The Collection presently has 18 slide rules that can be classified as vector rules.
Note that the Sun-Hemmi Model 153 is included here as it had special scales from which hyperbolic function values could be determined directly. This very special rule and its scales are described in a separate vignette, Hemmi 153 Scales.
|Blundell Rules Limited||506 Academy Duplex||1970-1980|