Utility knife tool

A utility knife tool having a handle with a distal portion and a blade extending therefrom. A blade cover for covering the blade is integral with the tool and cooperates with a blade cover retainment member for lockedly maintaining the blade cover in a position covering the blade when the tool is not in use. A hand operable releaser is provided for releasing the locked retainment member, while a hand operable blade cover driver moves the blade cover an exposure distance for exposing the blade. Also included is an intercept member for disengaging the blade cover driver upon blade movement exceeding the exposure distance as may occur in a panic or emergency situation during tool use such that the blade cover is automatically dispatched to the locking configuration covering the blade.

DETAILED DESCRIPTION OF THE INVENTION Referring first to FIGS. 1 - 3 , a preferably disposable utility knife tool 10 is illustrated having a handle 12 constructed of two opposing pieces 12 a , 12 b that form a generally hollow interior portion 14 . A generally cylindrical hollow blade cover 16 is integral with the tool 10 and covers the cutting edge 18 of a blade 20 when the tool 10 is not in use. The blade 20 extends from the distal portion 22 of the handle 12 and is secured between the two opposing pieces 12 a , 12 b thereof with a conventional rivet 24 passing through the handle apertures 26 a , 26 b and aligned blade aperture 28 therebetween. A longitudinal slit 30 in the wall of the blade cover 16 permits the blade 20 to reside there through. A second rivet 32 passes through both pieces 12 a , 12 b of the handle 12 near its proximal end to thereby maintain handle integrity. As particularly shown in FIGS. 2, 3 , and 8 , the underside of the blade cover 16 includes a transverse opening 34 , a longitudinal opening 36 extending proximal of the transverse opening 34 , and a ledge 38 , while the blade cover 16 itself has a proximal opening 40 through which projects a hollow cylindrical releaser 42 having a distal double ramp projection 44 , a central block projection 46 , and a proximal ledge projection 48 . An exteriorly accessible finger-movable trigger lever 50 extends from the handle 12 and has a hook 52 projecting toward the blade cover 16 . The trigger lever 50 is urged distally by a conventional compression spring 70 positioned within the handle 12 as shown in FIG. 3 . Extending within the hollow interior portion 14 of the handle 12 is a locking ring 54 through which the blade cover 16 resides and travels. Finally, a return spring 56 extends from a blade aperture 58 and through the releaser 42 to a releaser aperture 62 situated in a proximal rim 64 of the releaser 42 to thereby urge the releaser 42 distally. As is apparent, the rim 64 prevents the releaser 42 from entering the interior of the releaser 42 . FIGS. 4 A- 7 illustrate sequential operability of the knife tool 10 . As shown in FIG. 4 A, prior to operation, the hook 52 of the trigger lever 50 is adjacent the proximal ledge projection 48 of the releaser 42 while the border 66 of the locking ring 54 resides in the transverse opening 34 of the blade cover 16 and the distal double ramp projection 44 of the releaser 42 is forward of the locking ring 54 . Upon an initial trigger-lever finger movement as shown in FIG. 4 B, which preferably is about one-eighth inch, the hook 52 engages the proximal ledge projection 48 of the releaser 42 and moves the releaser 42 and its proximal ledge projection 48 proximally such that the projection 48 reaches a position within the transverse opening 34 of the blade cover 16 to fill a portion of the transverse opening 34 and thereby release locking-ring retention of the cover 16 . In particular, such release occurs because the proximal ledge projection 48 , by filling a portion of the transverse opening 34 as above described, functions to replicate the diameter of the blade cover 16 within the transverse opening 34 and thereby move the locking ring 54 from the transverse opening 34 to thus allow passage of the blade cover 16 through the locking ring 54 . Simultaneously, the hook 52 of the trigger lever 50 engages the ledge 38 of the blade cover 16 as clearly shown in FIG. 4B . FIG. 5 illustrates the useful configuration of the knife tool 10 . As there shown, the trigger lever 50 is moved proximally an exposure distance to thereby move the blade cover 16 proximally and expose the cutting edge 18 of the blade cover 16 . As long as the trigger lever 50 is maintained in this position, the knife tool 10 is fully functional for cutting material. However, and as illustrated in FIGS. 6 and 7 , if the trigger lever 50 is drawn proximally a further distance, as may occur in an emergency or hazardous situation, to thereby exceed the exposure distance, the proximal end of the releaser 42 becomes misaligned by striking the inclined ramp 68 within the travel path of the blade cover 16 inside the hollow interior portion 14 thereof and forces the hook 52 of the trigger lever 50 from the ledge 38 of the blade cover 16 . When this occurs, the return spring 56 immediately draws the blade cover 16 distally to cover the cutting edge 18 of the blade 20 while the locking ring 54 simultaneously engages the transverse opening 34 of the blade cover 16 for locked immobility and resulting minimization of potential injury because of an exposed blade 16 . In this manner, the knife tool 10 here defined permits both superb cutting efficiency and sensed potential injury to thereby provide equipment able to accomplish a favorable work product. While an illustrative and presently preferred embodiment of the invention has been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.