Patent ID: 7900363

Claim:
An exchange blade knife, comprising: (a) a handle, (b) an elongated replaceable blade of generally uniform thickness, the replaceable blade including a cutting edge, an opposite back edge, a base edge and an opening adjacent to the base edge, (c) a blade holder mounted to the handle, the blade holder having a proximate end and a distal end, the blade holder having a base portion at the proximate end thereof and a back edge portion extending away from the base portion toward the distal end thereof, the blade holder including a blade recess defined in the base portion and the back edge portion for receiving and holding the replaceable blade such that the portion of the blade recess in the area of the base portion of the blade holder receives and supports the base portion of the replaceable blade and such that the portion of the blade recess in the area of the back edge portion of the blade holder receives and supports at least most of the back edge of the replaceable blade, and a boss projecting from the surface of the blade recess of the base portion, the boss located and configured to be received by the opening in the replaceable blade, at least a portion of the boss projecting above the surface of the blade when the blade is received by the blade recess of the blade holder and when the boss is received by the opening in the blade, (d) a blade lock pivotably mounted to the blade holder at a pivot joint so that the blade lock is operable to pivot between an open position and a closed position, the blade lock having a channel shaped cross section along at least most of the length thereof, the channel shaped cross section including a back flange suitable for substantially covering the back surface of the blade holder and a front flange suitable for substantially covering the front surface of the blade holder and also suitable for extending over at least most of the back edge of the replaceable blade, whereby the replaceable blade is securely supported along at least most of the back edge of the replaceable blade when the blade lock is in the closed position, the blade lock and the blade holder arranged such that when the blade lock is in the open position, the replaceable blade is removable from the blade holder, the blade lock including a boss opening for receiving the boss of the blade holder when the blade lock is in the closed position thereby retaining the blade lock in the closed position.