Replaceable blade knife

Claim 1

A knife blade holder for a thin elongated blade having two sharpened longitudinally extending edges on opposed sides of said blade and an elongated open center portion having its longitudinal axis parallel to said edge, said holder comprising: a first and a second body section, each having a handle portion and a blade-holding portion with each blade holding portion having a flange; connecting means for connecting said sections together, said connecting means being located adjacent said blade-holding portions and having a tightened position for clamping said blade between said blade-holding portions and a first loosened position permitting separation while still connected together of said blade holding portions to define a passageway therebetween said passageway having one open end for slidable insertion and withdrawal of said blade into and out of said passageway and with said flanges forming walls which at least partly enclose said passaeway; said first blade-holding portion having a first ramped end at the opening of said passageway, a lip extending beyond said second blade holding portion and an internal elongated shoulder extending longitudinally in said passageway, said shoulder being ramped to blend smoothly with said first ramped end and dimensioned to engage said blade open center portion and positioned to hold the edges of said blade out of dulling contact with the walls of said passageway during insertion and withdrawal of said blade, said shoulder also formed to hold the edges of said blade out of dulling contact with the walls of said passageway when force is applied to said blade while work is performed with said blade; and said second blade-holding portion having a second ramped end at the opening of said passageway, a channel for receiving said shoulder when said connecting means is in tightened position and a flat face for frictionally engaging said blade when said connecting means is in said tightened positioned.