Abstract: A knife accommodating interchangeable blades. The knife includes a blade having a tang extending from its base, and an elongate handle having a front, blade-receiving region and an opposed back region. An elongate lever having opposed pivot and locking points is attached at its pivot point in the back region of the handle for swinging toward and away from a locked position in which the lever is axially aligned with the handle. The lever provides, adjacent its pivot point, a cammed surface dimensioned to engage a spring arm within the handle, thus to lock the lever in its locked position. The blade tang is securely held within a cavity defined in part by the locking point of the lever, with the latter in locked position.

Abstract: A retractable cutting implement, such as a utility knife, comprises a sleeve-like handle member having a cavity portion with the handle member being open at the base and at one end through a first longitudinal slot. A carrier member is pivotally mounted to the handle for pivotal movement into and out of the cavity with the carrier member being resiliently held within the cavity when it is pivotally moved into the cavity for substantially closing the cavity. The carrier member comprises a substantially enclosed longitudinally extending chamber with a passage therein in communication with the one end of the first slot in the handle member and a blade carriage member is slidably mountable in this chamber for slidable movement toward and away from the passage.

Abstract: A handle having a base member mounted on one end and a blade retainer member pivotally mounted on the base member. The base and retainer members have skirt portions for engagement with opposite side surfaces of a safety razor-type cutting blade, the retainer member being pivotally movable toward and away from a blade retaining position. Lugs on the base member are adapted to engage notches on a blade to lock the blade against movement relative to the base member.