Patent ID: 8752297

Claim:
A knife comprising: a blade support holding a blade; a primary knife part; a secondary knife part movable relative to the primary knife part and forming with the primary knife part a housing on which the blade support is pivotal about an axis fixed on the primary knife part; a first coupling associated with the blade support; a second coupling associated with the secondary knife part and detachably engageable with the first coupling in order to pivot the blade support as a result of movement of the primary knife part relative to the secondary knife part between a safety position in which the blade is retracted into the knife housing inaccessible to the user, and an intermediate position in which the blade projects from the knife housing; and a return spring biasing the blade support pivotally about the axis with a return force into the safety position such that a cutting force on the blade pivots the blade support about the axis out of the intermediate position into a cutting position in which the first coupling and the second coupling are disengaged from each other such that the blade support is pivoted by the return spring into the safety position.