Writing instrument

Claim 1

A multiple unit writing instrument comprising an elongated tubular barrel having a rear end and an opening at the forward writing end thereof and including relatively rotatable forward and rear coaxial barrel sections, a transversely extending spindle element located proximate the rear end of said barrel, a pair of elongated writing elements longitudinally reciprocatable in said barrel between advanced positions projecting through said opening and retracted positions, an elongated flexible member located in said barrel rearwardly of said opening and traversing a U-shaped path extending around a bearing face of said spindle element facing said rear end and extending forwardly thereof and having opposite ends coupled to respective writing elements to be movable therewith, whereby movement of one of said writing elements in one direction effects the movement of the other writing element in an opposite direction, and manually actuatable operating means for selectively longitudinally moving said writing elements and comprising a first guide member rotatable with said front barrel section and having a pair of longitudinally extending guide slots and supporting said spindle element, a cam follower member connected to each end of said flexible member and slidably engaging respective guide slots, means coupling each of said follower members to a respective writing element and a cylindrical cam rotatable with said rear barrel section and engaging said follower members thereby to longitudinally move said writing elements in opposite direction with relative rotation of said barrel sections.