A sliding rule for conversion tables, address directories and similar references, made of cardboard or the like

摘要

The sliding rule comprises a flat, window-bearing sheath of a stiff material, in which a sliding tablet of the same material is received, the sheath and the sliding tablet bearing correlated inscriptions or pictures. According to the invention, the sliding rule is made from a single blank of said stiff material, comprising a first and a second board (10, 12), of which at least one has windows, integrally joined and folded one upon the other and laterally bonded to form said sheath, and a third board (14) which is end-joined to said second board through an intermediate area (23), and is folded between said first and second board around a folding line (18) at the midline of said intermediate area, the intermediate area being removed for using the sliding rule, said third board acting as sliding tablet.