Autoretracting box-cutting knife

An autoretracting box-cutting knife comprising:

• a housing dimensioned to be held in a hand of a user and having a longitudinally forwardly projecting front end;
• a holder slidable longitudinally in the housing between a front position and a rear position;
• a blade secured in the holder, projecting forward from the housing in the front position of the holder, and retracted back into the housing in the rear position of the holder;
• a blade-actuating crank having an inner end and an outer end and provided with a movable slide;
• a pivot on the housing connected to the crank inner end and defining for the crank a transverse pivot axis;
• means including interengaging formations formed on the holder and the slide offset from the pivot for moving the crank with the holder between a rear position with the crank outer end projecting laterally from the housing in the rear position of the holder and a front position in the front position of the holder;
• and;
• a spring engaged between the holder and the housing urging the holder and the crank into the respective rear positions, whereby when the outer end of the crank is pushed forward to push the crank into the front position the holder is pushed forward into the front position and the blade projects from the housing.

An autoretracting box-cutting knife comprising:

• a housing formed of a pair of halves one of which has an inwardly projecting pin, dimensioned to be held in a hand of a user, and having a longitudinally forwardly projecting front end;
• a holder slidable longitudinally in the housing between a front position and a rear position;
• a blade secured in the holder, projecting forward from the housing in the front position of the holder, and retracted back into the housing in the rear position of the holder;
• a blade-actuating crank having an inner end and an outer end;
• a pivot formed by the pin, connected to the crank inner end, and defining for the crank a transverse pivot axis;
• means including interengaging formations on the crank and the holder offset from the pivot for moving the crank with the holder between a rear position with the crank outer end projecting laterally from the housing in the rear position of the holder and a front position in the front position of the holder;
• and
• a spring engaged between the holder and the housing urging the holder and the crank into the respective rear positions, whereby when the outer end of the crank is pushed forward to push the crank into the front position the holder is pushed forward into the front position and the blade projects from the housing.