Cutlery – Carton openers
Reexamination Certificate
2003-01-10
2004-04-13
Ashley, Boyer D. (Department: 3724)
Cutlery
Carton openers
C030S286000, C030S294000
Reexamination Certificate
active
06718637
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a utility knife that reduces or eliminates the chances of accidental cuts. More particularly, this invention relates to a utility knife with a safety hood which automatically locks closed after the blade is used to make a single cut in a cardboard box or the like.
BACKGROUND OF THE INVENTION
Utility knives are well known and have a wide variety of uses. A well-recognized problem with these knives is that the user often accidentally cuts his/herself. This can occur when the user is handling and/or carrying the knife or accidentally cutting himself or herself when using the knife.
In many of the uses of utility knives, such as opening boxes or cutting linoleum, the user is often pulling the knife back towards his/her body, which is the most common way the user gets cut. When the knife reaches the edge of the work surface next to the user's body, the knife is accidentally pulled across the user's leg or other hand. The likelihood of such an injury is increased when the user is doing repetitive tasks. Many attempts have been made to make utility knives safer. Some of the patents attempting to address this issue are listed below.
U.S. Pat. No. 2,376,887 to Walters (1944) discloses a utility knife with a safety hood which is biased closed with a spring.
U.S. Pat. No. 2,889,623 to Baker (1957) discloses a wallpaper cutter where the cutting blade is forced down from between two rollers by thumb pressure.
U.S. Pat. No. 3,781,988 to Jones (1975) discloses a utility knife with a hood covering the blade. The hood is held down over the blade with a spring. Pressure on the bottom of the hood will expose the knife blade.
U.S. Pat. No. 3,999,290 to Wood (1976) discloses a utility knife with an automatically retracting blade.
U.S. Pat. No. 4,531,286 to Vito et al. (1985) discloses a utility knife with a hood covering the blade. The blade is uncovered by pressing a release lever built into the body. The release lever is depressed by normal gripping of the body. Pressing the bottom of the hood against a box could also expose the blade.
U.S. Pat. No. 4,868,985 to Rehn (1989) discloses a utility knife with an automatically retracting knife blade.
U.S. Pat. No. 5,241,750 to Chomiak (1993) discloses a utility knife with a hood covering the blade. The hood is held down over the blade with a spring. Pressure on the bottom of the hood will expose the knife blade. A lock lever allows the hood to be locked closed.
U.S. Pat. No. 5,386,632 to Schmidt (1995) discloses a utility knife with a retractable blade.
U.S. Pat. No. 5,404,645 to Janser (1995) discloses a utility knife with a moveable blade that can be placed in one of three different positions to provide three different cutting depths.
U.S. Pat. No. 5,494,670 to Quinn (1996) discloses a utility knife with a moveable blade pushed forward by the user.
U.S. Pat. No. 5,522,135 to Votolato (1996) discloses a utility knife with a hood covering the blade. The hood is held down over the blade with a spring. Pressure on the bottom of the hood will expose the knife blade.
U.S. Pat. No. 5,604,984 to Shepherd et al. (1997) discloses a utility knife with a rotary blade magazine. The blades can be moved in and out of the magazine as needed.
U.S. Pat. No. 5,613,300 to Schmidt (1995) discloses a utility knife with a retractable blade.
U.S. Pat. No. 5,617,635 to Berns (1997) discloses a utility knife with an automatically retracting blade.
U.S. Pat. No. 5,909,930 to Ragland, III et al. discloses a utility knife with a retractable blade.
U.S. Pat. No. 5,940,970 to D'Ambro, Sr. et al. discloses a utility knife with a retractable blade.
U.S. Pat. No. 6,070,326 to Berns discloses a utility knife with a retractable blade guard. The blade guard is a wire cage which extends around the blade and retracts back over it. A knife made by Martor-Argentax, assignee of the Berns patent had the same blade guard which is pushed back over the front edge of the blade, exposing the front point first, then sliding back perpendicular to the cutting surface. The blade guard is locked in position over the blade. The user must depress a release latch on the knife to allow the guard to move. Once the guard had moved, exposing the front edge of the blade, the release latch must be release and then re-depressed to release the cover again. The cover slides back into the body of the knife.
The two most common types of “safety knives” have either a retracting blade or a movable hood covering the blade. The retracting blades can be manual or automatic. The manual retractors do not solve the problem of accidental cuts while using the knife. Some of the auto-retracting blades have a button that must be depressed or pushed forward and held to keep the blade but. This reduces many accidental cuts, but often does not solve the problem of cuts that happen coming off the edge of the cutting surface. The user is not likely to release the button the second they reach the edge, particularly if they are cutting multiple things. In addition, keeping the button depressed can cause stress and cramping in the user's hand. Another danger of the auto-retracting blades is that the user can accidentally have his/her index finger at the front edge of the knife, against the blade, when it is retracted, cutting the finger.
The prior art utility knives with safety hoods are another attempt to reduce accidental cuts. The prior art hoods are generally biased closed with a spring or similar mechanism. Pressing on the bottom edge of the hood pushes the hood back, revealing the blade. Once the pressure on the bottom edge is released the hood closes again. The problem with these hoods is that as the user is drawing the knife across their leg or other body part accidentally they are putting pressure on the bottom edge of the hood, thereby exposing the blade.
The Martor knife with the wire blade guard is another type of safety knife. The Martor knife is designed to push the front edge of the blade through a surface to start the cutting. See FIG. 1
a
, '326 patent. Then the knife is pulled thought the working surface, against the cutting edge. This design does not work well for cutting open boxes as it requires puncturing into the box, risking cutting merchandise.
Another problem that is common with the use of utility knives is accidentally cutting what is under the cutting surface. For example, it is a common problem to have merchandise damaged by being accidentally cut when the shipping box is cut open. It is known in the art to restrict the depth of cut of the knife blade by reducing the amount the blade extends from the body of the knife. In the prior art knives the blade can be moved to extend different lengths beyond the body of the knife, allowing different depths of cut. However, all of the prior art knives move the blade of the knife to adjust the depth of cut. This is often a cumbersome process and it is not always easy to switch between cutting depths.
What is needed is a utility knife wherein the blade cannot be accidentally uncovered and will automatically close and lock a hood once the blade is removed from the cutting surface. Additionally the utility knife should allow the user to choose the depth of cut easily and to change easily between depths of cut.
The present invention solves these problems by having an automatically locking hood to cover the blade. The hood cannot move until a button is depressed to release the lock. The knife can then be used to cut a desired surface. The hood rotates back from the cutting edge when pressure is applied at the bottom edge of the hood by the cutting surface. The hood rotating back and then forward again resets the lock so that as soon as the pressure on the bottom edge is removed the hood closes and is re locked. The hood also controls the depth of cut of the blade. A movable, positive stop on the knife is used to control the amount that the hood can rotate back from the edge of the blade, preventing over cutting.
SUMMARY OF THE INVENTION
The primary aspect of the present invention is to provide a
Kueffner Fred K.
Ortner Mel Wayne
Schwartz Donald R.
Turley Timothy A.
Ashley Boyer D.
Ortner Mel Wayne
Patent Law Offices of Rick Martin P.C.
Polson Margaret
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