Replaceable blade knife

A holder for a planar blade having a forward end and an opposed rear end, a sharp edge, and defining an elongated aperture having a constriction at one end, the holder comprising:

• an elongated body having opposed ends;
• the elongated body having a handle portion extending to a handle end of the elongated body, and a blade attachment facility at an opposed forward end of the elongated body;
• the blade attachment facility having a blade support surface configured to abut a major face portion of the planar blade proximate the elongated aperture;
• an elongated boss sized to closely receive the elongated aperture of the planar blade;
• the elongated boss defining an undercut configured to receive a blade portion at the constriction to prevent separation of the planar blade from the blade support surface when the planar blade is in an installed condition with the elongated boss received in the elongated aperture;
• a movable ejector element connected to the elongated body and operable engage the rear end of the planar blade to eject the planar blade from the holder;
• and
• wherein the movable ejector element has a ledge at a different level from the blade support surface and configured to retain the rear end of the planar blade above the blade support surface.

A holder for a planar blade having a forward end and an opposed rear end, a sharp edge, and defining an elongated aperture having a constriction at one end, the holder comprising:

• an elongated body having opposed ends;
• the elongated body having a handle portion extending to a handle end of the elongated body, and a blade attachment facility at an opposed forward end of the elongated body;
• the blade attachment facility having a blade support surface configured to abut a major face portion of the planar blade proximate the elongated aperture;
• an elongated boss sized to closely receive the elongated aperture of the planar blade;
• the elongated boss defining an undercut configured to receive a blade portion at the constriction to prevent separation of the planar blade from the blade support surface when the planar blade is in an installed condition with the elongated boss received in the elongated aperture;
• a movable ejector element connected to the elongated body and operable engage the rear end of the planar blade to eject the planar blade from the holder;
• and
• wherein the movable ejector element has a ledge at a different level from the blade support surface and configured to retain the rear end of the planar blade above the blade support surface.

A holder for a planar blade having a forward end and an opposed rear end, a sharp edge, and defining an elongated aperture having a constriction at one end, the holder comprising:

• an elongated body having opposed ends;
• the elongated body having a handle portion extending to a handle end of the elongated body, and a blade attachment facility at an opposed forward end of the elongated body;
• the blade attachment facility having a blade support surface configured to abut a major face portion of the planar blade proximate the elongated aperture;
• an elongated boss sized to closely receive the elongated aperture of the planar blade;
• the elongated boss defining an undercut configured to receive a blade portion at the constriction to prevent separation of the planar blade from the blade support surface when the planar blade is in an installed condition with the elongated boss received in the elongated aperture;
• a movable ejector element connected to the elongated body and operable engage the rear end of the planar blade to eject the planar blade from the holder;
• wherein the movable ejector element has a forward-facing shoulder surface configured to engage a rear end of the planar blade to enable ejection of the planar blade when the rear end of the planar blade is deviated above the blade support surface;
• and
• wherein the movable ejector element has a ledge at a different level from the blade support surface and configured to retain the rear end of the planar blade above the blade support surface, and wherein the ledge is adjacent to the forward-facing should surface.

A holder for a planar blade having a forward end and an opposed rear end, a sharp edge, and defining an elongated aperture having a constriction at one end, the holder comprising:

• an elongated body having opposed ends;
• the elongated body having a handle portion extending to a handle end of the elongated body, and a blade attachment facility at an opposed forward end of the elongated body;
• the blade attachment facility having a blade support surface configured to abut a major face portion of the planar blade proximate the elongated aperture;
• an elongated boss sized to closely receive the elongated aperture of the planar blade;
• the elongated boss defining an undercut configured to receive a blade portion at the constriction to prevent separation of the planar blade from the blade support surface when the planar blade is in an installed condition with the elongated boss received in the elongated aperture;
• a movable ejector element connected to the elongated body and operable engage the rear end of the planar blade to eject the planar blade from the holder;
• including a flexure element operable to flex the rear end of the planar blade away from the blade support surface;
• and
• wherein the movable ejector element is movable between a first operational position in which the planar blade is unflexed and abuts the blade support surface, a second position to the rear of the first position in which flexure of the rear end of the planar blade away from the blade support surface is enabled, and wherein the flexure element is prevented by contact of the movable ejector element and the planar blade from flexing the planar blade when the movable ejector element is in the first position.

A holder for a planar blade having a forward end and an opposed rear end, a sharp edge, and defining an elongated aperture having a constriction at one end, the holder comprising:

• an elongated body having opposed ends;
• the elongated body having a handle portion extending to a handle end of the elongated body, and a blade attachment facility at an opposed forward end of the elongated body;
• the blade attachment facility having a blade support surface configured to abut a major face portion of the planar blade proximate the elongated aperture;
• an elongated boss sized to closely receive the elongated aperture of the planar blade;
• the elongated boss defining an undercut configured to receive a blade portion at the constriction to prevent separation of the planar blade from the blade support surface when the planar blade is in an installed condition with the elongated boss received in the elongated aperture;
• a movable ejector element connected to the elongated body and operable engage the rear end of the planar blade to eject the planar blade from the holder;
• including a flexure element operable to flex the rear end of the planar blade away from the blade support surface;
• and
• wherein the flexure element is connected to the movable ejector element.

A holder for a planar blade having a forward end and an opposed rear end, a sharp edge, and defining an elongated aperture having a constriction at one end, the holder comprising:

• an elongated body having opposed ends;
• the elongated body having a handle portion extending to a handle end of the elongated body, and a blade attachment facility at an opposed forward end of the elongated body;
• the blade attachment facility having a blade support surface configured to abut a major face portion of the planar blade proximate the elongated aperture;
• an elongated boss sized to closely receive the elongated aperture of the planar blade;
• the elongated boss defining an undercut configured to receive a blade portion at the constriction to prevent separation of the planar blade from the blade support surface when the planar blade is in an installed condition with the elongated boss received in the elongated aperture;
• a movable ejector element connected to the elongated body and operable to engage the rear end of the planar blade to eject the planar blade from the holder;
• and
• a flexure element operable to flex the rear end of the planar blade away from the blade support surface.