The invention relates to a retractable blade utility knife handle and more particularly to a retractable blade utility knife handle having a pair of releasably locking, pivotable handle halves.
In retractable-blade utility knives, the blade is slidably movable from a sheathed position to an extended unsheathed position wherein the knife blade projects through an opening in the knife handle to present a cutting edge. Such a utility knife is disclosed in Weimann U.S. Pat. No. 4,663,845, entitled "Utility Knife" wherein the knife incorporates a blade carrier which mounts and supports the blade within the interior of the knife handle for selective longitudinal movement therein. The blade carrier includes a thumb actuated button to release the blade carrier from one of several latching positions for slidably shifting the blade to another longitudinal position. The halves of the knife handle are connected by a central pivot. The handle halves are releasably locked so that they can be pivoted laterally relative to one another when the blade carrier is in any longitudinally shifted position, thereby allowing the blade to be replaced and providing access to a blade storage compartment.
A typical shortcoming of retractable-blade utility knives is the lack of stability of the blade when the knife is forcibly twisted sideways during use. For example, under conditions in which a substantial force is applied to the side of the blade proximate the lower cutting edge, it is possible for the lower edge of the blade to slip off of the blade carrier, thereby freeing the blade to fall out of the handle. Another drawback of conventional utility knife handles is the possibility that the handles can be opened inadvertently. Yet another shortcoming of conventional utility knives is that the blade carrier and blade tend to rattle, as they are not fixed to the handle. A further drawback of conventional retractable blade knives is that if the blade carrier is shifted longitudinally when no blade is installed in the blade carrier, the corners of the blade carrier, on occasion, will become stuck at various locations in the handle, causing the blade carrier to shift or slide irregularly.