Patent ID: 7107688

Claim:
A utility knife, comprising: an outer housing having a top, a bottom, and first and second lateral sidewalls extending between said top and said bottom; said sidewalls being longer than said top and said bottom in cross-section; said housing further having a forward opening; a blade carriage having a blade-receiving bay; said blade carriage moveable horizontally in said housing to move a cutting blade disposed in said bay from a retracted position to a deployed position, said cutting blade extending through said forward opening in said deployed position; a locking mechanism operative to releasably couple said cutting blade to said carriage; said locking mechanism connected to said carriage for horizontal movement therewith; wherein said locking mechanism comprises a lock plate having an blade-engagement element; said locking plate moveable by non-pivoting, generally vertical displacement between a locked position operative to couple said cutting blade to said carriage for horizontal movement therewith and an unlocked position wherein said cutting blade can be removed from said carriage; said locking mechanism biased toward said locked position; and a first actuator moveable by a user to engage said locking mechanism and move said locking mechanism from said locked position to said unlocked position.