Abstract: A utility knife includes a hollow handle having a slot and an opening at each end. A razor is slidable between each end of the handle and may protrude at each opposing end for cutting use. The razor is mounted to a shuttle which includes a tab that is positioned within the slot. The user may use the tab to slide the shuttle and the blade within the handle between the two ends, as desired. A U-shaped blocking component is pivotally attached to the handle and is used to block sliding movement of the tab beyond a midpoint of the handle to prevent the razor protruding into the user's hand. The user must unlock the blocking element to safely allow the shuttle to be slid past.

Abstract: A low cost disposable utility knife includes a hollow handle having an elongated slot and an opening at each end. A blade shuttle holds a trapezoidal razor blade and is slidably mounted on tracks integrally formed within the hollow handle and slidable between each end of the handle. When the shuttle is located at either end, a cutting edge of the razor extends beyond the opening of the adjacent handle end and is accessible for useful cutting work by a user. The shuttle includes a tab that is positioned within the elongated slot and includes a portion that is accessible to the user. The user may use the accessible tab to slide the shutter and the blade within the handle between the two ends, as desired. A U-Shaped flip lock is pivotally attached to the handle between a down position, wherein the tab is physically blocked from sliding along the elongated slot, and an up position, wherein the tab is permitted to slide along the elongated slot, passing under the U-shaped flip lock.