Self-retracting knife with replaceable blade

A self-retracting utility knife comprising

• an elongated housing having mating sections connected together and with a forward end portion defining a blade aperture,
• a blade carrier within the housing and having a forward end portion supporting a replaceable flat knife blade,
• the housing supporting the blade carrier for linear movement between a fully extended position with the knife blade projecting forwardly from the blade aperture and a fully retracted position with the knife blade in the housing,
• a spring member within the housing and connected to urge the blade carrier and knife blade continuously from the fully extended position to the fully retracted position,
• a hand operated member connected to the blade carrier for moving the blade carrier and knife blade against the spring member toward the fully extended position in response to forward pressure on the hand operated member,
• an anti-retraction latch member supported for movement within the housing and responsive to continuous inward pressure for engaging and stopping retracting movement of the blade carrier at an extended position from the fully retracted position,
• the latch member requiring continuous inward pressure to hold the blade carrier at the extended position,
• the blade carrier and knife blade move to the fully retracted position by the spring member when the inward pressure on the latch member is released, and
• the anti-retraction latch member is biased downwardly through an opening within a lower portion of the housing and is adapted to receive upward pressure for moving the latch member.

A self-retracting utility knife comprising

• an elongated housing having mating sections connected together and with a forward end portion defining a blade aperture and a rearward end portion defining a blade carrier aperture,
• an elongated blade carrier within the housing and having a forward end portion supporting a replaceable flat knife blade and a rearward end portion,
• the housing supporting the blade carrier for linear movement between a fully extended position with the knife blade projecting forwardly from the blade aperture and a fully retracted position with the rearward end portion of the blade carrier projecting rearwardly from the blade carrier aperture,
• a first spring member within the housing and connected to urge the blade carrier and knife blade continuously from the fully extended position to the fully retracted position,
• the blade carrier and knife blade movable against the first spring member toward the fully extended position in response to forward pressure on the projecting rearward end portion of the blade carrier,
• an anti-retraction latch member supported for movement within the housing against a second spring member and responsive to continuous inward pressure for engaging and stopping retracting movement of the blade carrier at an extended position from the fully retracted position,
• the latch member requiring continuous pressure against the second spring member to hold the blade carrier at the extended position,
• the blade carrier and knife blade move to the fully retracted position by the first spring member when both forward pressure on the blade carrier and the inward pressure on the latch member are released, and
• a blocking member engaging the blade carrier for preventing movement of the blade carrier and knife blade from the fully retracted position toward the fully extended position until the blocking member is removed from engagement with the blade carrier.

A self-retracting utility knife comprising

• an elongated housing having mating sections connected together and with a forward end portion defining a blade aperture and a rearward end portion defining a blade carrier aperture,
• an elongated blade carrier within the housing and having a forward end portion supporting a replaceable flat knife blade and a rearward end portion,
• the housing supporting the blade carrier for linear movement between a fully extended position with the knife blade projecting forwardly from the blade aperture and a fully retracted position with the rearward end portion of the blade carrier projecting rearwardly from the blade carrier aperture,
• a first spring member within the housing and connected to urge the blade carrier and knife blade continuously from the fully extended position to the fully retracted position,
• the blade carrier and knife blade movable against the first spring member toward the fully extended position in response to forward pressure on the projecting rearward end portion of the blade carrier,
• an anti-retraction latch member supported for movement within the housing against a second spring member and responsive to continuous inward pressure for engaging and stopping retracting movement of the blade carrier at an extended position from the fully retracted position,
• the latch member requiring continuous pressure against the second spring member to hold the blade carrier at the extended position,
• the blade carrier and knife blade move to the fully retracted position by the first spring member when both forward pressure on the blade carrier and the inward pressure on the latch member are released, and
• the anti-retraction latch member includes a plurality of stop surfaces for stopping retraction of the knife carrier and knife blade at a plurality of positions spaced inwardly from the fully extended position.

A self-retracting utility knife comprising

• an elongated housing having mating sections connected together and with a forward end portion defining a blade aperture and a rearward end portion defining a blade carrier aperture,
• an elongated blade carrier within the housing and having a forward end portion supporting a replaceable flat knife blade and a rearward end portion,
• the housing supporting the blade carrier for linear movement between a fully extended position with the knife blade projecting forwardly from the blade aperture and a fully retracted position with the rearward end portion of the blade carrier projecting rearwardly from the blade carrier aperture,
• a first spring member within the housing and connected to urge the blade carrier and knife blade continuously from the fully extended position to the fully retracted position,
• the blade carrier and knife blade movable against the first spring member toward the fully extended position in response to forward pressure on the projecting rearward end portion of the blade carrier,
• an anti-retraction latch member supported for movement within the housing against a second spring member and responsive to continuous inward pressure for engaging and stopping retracting movement of the blade carrier at an extended position from the fully retracted position,
• the latch member requiring continuous pressure against the second spring member to hold the blade carrier at the extended position,
• the blade carrier and knife blade move to the fully retracted position by the first spring member when both forward pressure on the blade carrier and the inward pressure on the latch member are released, and
• the anti-retraction latch member is biased downwardly through an opening within a lower portion of the housing and is adapted to receive upward pressure for moving the latch member.