Cutlery – Carton openers
Reexamination Certificate
1999-08-09
2001-01-30
Payer, Hwel-Siu (Department: 3724)
Cutlery
Carton openers
C030S294000
Reexamination Certificate
active
06178640
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to slitting devices, as are used for opening boxes, and more particularly, to an improved device of simple, compact, heavy duty lightweight construction and enabling its throw-away disposal.
There is need for devices, as referred to above, and in particular, there is need for very low cost such devices which are made to be thrown away without danger, which could otherwise be presentd by slitting blade exposure.
SUMMARY OF THE INVENTION
It is a major object to provide an improved box opener in the form of a slitting device of simple, low cost, compact, throw-away construction, and which is safe to use, and safe when thrown away by virtue of blade protection. Basically, the device comprises:
a) a blade having a cutting edge,
b) a holder for the blade, including a handle, and a terminal on the handle retaining the blade with the blade edge protruding,
c) a shield carried by the holder proximate the terminal, for movement between extended position in which the blade is protected, and retracted position in which the blade edge is exposed for cutting,
d) there being a torsion spring carried by the holder and having an arm biasing the shield toward extended position,
e) the spring arm projecting in a hollow defined by the shield, the shield having blade protection sections extending parallel to the blade at opposite sides thereof.
As will be seen the holder may typically include a blade retaining insert plate carried by the terminal, the blade carried adjacent the insert plate with the blade edge projecting in skewed relation to the holder, in shield retracted position, the torsion spring biasing the shield toward that extended position.
It is another object of the invention to provide a torsion spring arm having camming engagement with a surface carried by the shield, whereby that surface slides along the spring arm, lengthwise thereof, as the shield moves between retracted and extended positions. As will be seen, that surface is typically defined by a projection on the shield, in the shield.
A further object of the invention is to provide a shield having an uppermost projecting portion extending above the level of holder terminal when the handle extends generally horizontally, for engagement with the user's finger or thumb when the handle is gripped, whereby the shield may be moved to retracted position by finger or thumb pressure exerted on said uppermost portion. The utility knife can be operated two ways. Either the user pulls the blade guard back with his/her thumb or other finger to expose the blade, or the user simply pushes the slitter down on the surface being cut forcing the blade guard to unlock and open thus exposing the blade and start the cutting. This is the preferred way to use the utility knife.
Yet another object is to provide a blade holder including an insert plate carried by the terminal, the blade carried proximate the insert plate with the blade edge projecting in a skewed relation to a lower edge defined by the insert plate, below the torsion spring, the shield having a forward portion extending protectively forwardly of the blade in blade extended position.
A further object is to provide a shield uppermost portion that tapers upwardly and rearwardly above the blades and spring, in shield extended position.
An added object is to provide a cooperative relation between a blade shield and a spring, defined by
a) a slitter blade and a handle carrying said blade,
b) a shield carried by the handle and pivotable between extended position in which the shield extends in protective relation to the blade, and retracted position, in which the blade is exposed for slitting,
c) a spring located to urge the shield toward extended position,
d) the spring having an elongated arm, and the shield having a projecting portion defining a hollow to increasingly receive the spring arm as the shield pivots toward extended position,
e) said projecting portion of the shield adapted to be gripped to effect shield pivoting.
An additional object is to provide shield opposite side sections at opposite sides of the holder terminal, said opposite side sections pivotally carried by said terminal, generally vertically below an uppermost portion of the shield.
A yet further object is to provide a first stop shoulder on the shield spaced above the handle, when the handle extends generally horizontally, the first stop shoulder being engagable with the handle when said uppermost shield portion is pivoted rearwardly and upwardly to shield retracted position.
It is a yet further and important object of the invention to provide a versatile safety guide in combination with the slitter, to facilitate rapid, easy and accurate slitting of objects such as paste-board boxes, and the like, the guide carried by the slitter to slidably engage one surface of an object to be slit while the bladed projects in slitting relation to another surface of the slitter. The guide can, for example, be carried by the pivoted blade shield, as for example in a selected one of two guide positions. This enables a user to either snap a safety knife guide on the right or left side of the utility knife blade, depending on if he/she is left or right handed. This eliminates need to have a separate cutter for left handed and right handed individuals. A user can also operate the utility knife without a guide in place. The utility knife is not limited to cutting box or paper stock. It is also used to slit film, foil, plastics, strapping, wallpaper, vinyl, leather, and other items usually requiring slitting by a utility knife.
One objective of such a guide is to help the user cut the top of a box off from the side instead of the top. The guide rests on the box top while the blade penetrates the side and cuts it (the top) off. The guide also protects the user from injury should the utility knife slip while in the process of cutting. The guide can also be used to cut the top of a box off from the top position. A right handed user would simply snap the safety knife guide in the right handed slot and cut down on the box using the safety knife guide along the right side of the box as a guide. A left-handed user would do the opposite.
These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following specification and drawings, in which:
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Haefliger William W.
Payer Hwel-Siu
Spellbound Development Group, Inc.
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