Utility knife with actuator for moving blade carrier and for releasing blade therefrom, and related method

A utility knife has a blade carrier defining a blade support surface movably mounted in a housing between retracted and extended positions. A catch is mounted on the blade carrier and is movable between a first position engagable with a blade seated on the blade carrier and substantially preventing the blade from moving relative to the blade carrier, and a second position spaced away from the blade located on the blade carrier and permitting removal of the blade from the blade carrier. An actuator is mounted on the blade carrier and is operable to move the blade carrier between the retracted and extended positions to, in turn, move a blade located on the blade carrier between retracted and extended positions, and move the catch between the first and second positions to release a blade from the blade carrier. The housing has a nose portion that defines the blade aperture and is made of a more wear-resistant material than the other portions of the housing. A sheet material spare blade holder is mounted within the housing and defines a fold, a support portion located on one side of the fold, and a biased retaining portion located on the other side of the fold for receiving spare blades therebetween.