US Patent 7448136 Utility knife

A utility knife includes a housing having a compartment for receiving one or more spare knife blades, a blade carrier slidably received in the housing for supporting and moving a knife blade into and out of the housing, and a pushing device for selectively pushing and feeding one of the spare knife blades into the blade carrier without opening or detaching the housing. A pusher is slidably received in the housing and has an edge for engaging with and for moving the spare knife blade to the blade carrier, and a spring element may move the pusher relative to the housing and to offset the pusher from the spare knife blade. A hand grip may be used to move the pusher relative to the housing.