Patent ID: 8734040

Claim:
A multi-function writing instrument comprising: a front section having a writing point opening; at least three marking tips held inside the front section, said marking tips being alternately selectable for extension through the writing point opening to a use position, one of said marking tips being a pencil lead marking tip; a rear section having an eraser opening, the rear section and the front section being rotatably connected to each other; an eraser holder movably disposed in the rear section, the eraser holder being selectable for extension through the eraser opening, the eraser holder having an eraser follower; an eraser mounted in the eraser holder; a guide disposed in the front section, the guide having a plurality of channels; a plurality of cam followers, each cam follower being slidably mounted in at least one of the plurality of channels, each cam follower being connected to a marking tip; a means for biasing each cam follower toward the eraser opening; a cam assembly rotatably connected to the guide, the cam assembly having a first cam face and a second cam face, the first cam face having a first cam path with a first cam apex for engaging the cam follower upon rotation of the cam assembly relative to the guide, the first cam apex biasing the cam follower toward the writing point opening, whereby the writing tip connected to the cam follower passes through the writing point opening, the second cam face having a second cam path with a second cam apex for engaging the eraser follower upon rotation of the cam assembly relative to the guide, the second cam apex biasing the eraser follower toward the eraser opening, whereby the eraser passes through the eraser opening upon rotation of the cam assembly relative to the guide; and a means for locking the guide and the cam assembly together against relative rotation when the cam follower connected to the pencil lead writing tip is urged by the first cam apex.