Safe utility knife

• US 4,713,885 A
• Filed: 12/08/1986
• Issued: 12/22/1987
• Est. Priority Date: 12/08/1986
• Status: Expired due to Term

• Current Assignee: The Hidden Edge Co., Inc.
• Original Assignee: John C. Whitehouse, Michael V. Couture, Ronald Keklak
• Inventors: Keklak, Ronald, Couture, Michael V., Whitehouse, John C.
• Primary Examiner(s): Watts, Douglas D.
• Application Number:
  US06/939,004
• Time in Patent Office: 379 Days
• Field of Search: 30/2, 30/66, 30/162, 30/163, 30/324, 30/335, 30/336, 81/363, 81/320, 81/371
• US Class Current: 30/162
• CPC Class Codes: B26B 5/003 comprising retraction means for the blade or the blade holder

Abstract

A utility knife utilizing a standard commercial blade as a handle forming a guide for a blade slide and also serving as a housing for the blade in a retracted safe position. The blade slide is advanced and retracted by a toggle linkage connected with an operating lever pivotally attached to the handle and biased by a spring to a position causing automatic retraction of the blade into the housing when the lever is released. When the lever is grasped and pulled toward the handle for advancing the blade to a use position, the toggle linkage assumes a straight line dead center slide and blade locking position.

Claims

1. A safe utility knife comprising a handle body portion having a linear guideway, a blade slide and blade mounted for movement in the linear guideway and being shiftable therein between a blade enclosed non-use position to a blade extended use position where the blade projects outside of said guideway, and a toggle mechanism including a pair of toggle links connected between said blade slide and guideway and a lever pivoted to the guideway and having a lost motion connection with said toggle links, means biasing the toggle mechanism in a direction maintaining said blade in the enclosed non-use position, and the handle body portion having substantially a pistol configuration including a hand grip, and said lever being in the form of a trigger at the forward side of the hand grip.

2. A safe utility knife comprising a handle body portion having a linear guideway, a blade slide and blade mounted for movement in the linear guideway and being shiftable therein between a blade enclosed non-use position to a blade extended use position where the blade projects outside of said guideway, and a toggle mechanism including a pair of toggle links connected between said blade slide and guideway and a lever pivoted to the guideway and having a lost motion connection with said toggle links, means biasing the toggle mechanism in a direction maintaining said blade in the enclosed non-use position, the handle body portion comprising a substantially straight elongated body portion, said lever being pivoted to the body near corresponding ends of the lever and body portion and the lever extending longitudinally of the body portion for a major portion of its length, and a guard for said lever connected between opposite ends of said substantially straight elongated body portion.

3. A safe utility knife comprising a handle body portion having a linear guideway, a reciprocatory blade slide adapted to mount a standard cutting blade within said guideway, a pair of pivoted toggle links connected between the blade slide and handle body portion, the handle body portion having a longitudinal slot within which said toggle links operate when moving between collapsed and extended straight line dead center positions, an operating lever pivotally connected to the handle body portion and having a slotted lost motion connection with an intermediate pivot element connecting said toggle links, and a biasing spring connected with said lever biasing it away from the handle body portion and biasing said toggle links toward said collapsed position and biasing said blade slide toward a fully enclosed non-use position inside of said handle body portion.

4. A safe utility knife as defined in claim 3, and one of said toggle links being pivotally attached to a rear corner of the blade slide near one guide surface of said linear guideway, and the other toggle link being pivotally attached to said body portion rearwardly of said slide and near said one guide surface, whereby said toggle links are close to, parallel with and extending longitudinally of said one guide surface when in the extended straight line dead center positions.