Apparatus and method for slitting boxes

An apparatus and method for cutting open a sealed box. A box typically has several of planar panels having a thickness and which panels meet at edges to define a box length, width and height and a central cavity. A box is conveyed to a cutting station where it is urged against a rotating blade which cuts through a box edge and pierces parallel to the plane of and into the thickness of one of the planar panels without entering the central cavity. The apparatus and method are useful for slitting boxes containing rectangular objects without marring the box contents. The apparatus is particularly useful for cutting open boxes containing books or the like, without damaging the box contents.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an apparatus and method for slitting boxes 
and more particularly, for cutting boxes containing rectangular objects 
without marring the box contents. The apparatus is particularly useful for 
cutting open boxes containing books and the like, without damaging the box 
contents. 
2. Description of the Prior Art 
It is long been desired in the art to be able to safely cut open boxes 
which package rectangular materials without damaging the contents. In the 
book publishing industry, sample books are often sent to consumers subject 
to their personal satisfaction and approval. As a consequence, such books 
are very often returned and must be processed by the publisher. Processing 
includes opening packaging materials and examining the returned items for 
damage. Books which are in excellent condition are available for resale, 
however, damaged books must be destroyed at great economic loss. Current 
practice in the art is for book return packages to be opened manually. 
Such labor intensive processing is very costly and one of the causes of 
book damage is human error in the opening process. The prior art has 
attempted to alleviate this problem by providing automated cutting 
equipment to open the returned packages. This has led to still further 
problems. Current box cutting machinery have blades which attack the box 
either perpendicularly or at an oblique angle to the plane of the book 
contents. In this regard, U.S. Pat. No. 5,048,267 teaches one cutting 
method for opening a rectangular package by forming a space between the 
package and the contents, cutting an edge, inserting a backplate and 
cutting the packaging on the surface of the backplate. This requires 
excessive manipulation steps. U.S. Pat. No. 5,074,097 shows a means for 
removing box tops by means of a cutting fluid under pressure. Such would 
not be useful for contents which must be kept dry. U.S. Pat. No. 5,275,524 
shows an apparatus for cutting packaging material for cans by deforming 
the packing under vacuum conditions prior to cutting. This apparatus would 
not be useful for rectangular packaged items. U.S. Pat. No. 5,101,703 
shows a box cutting method and apparatus using rotary knives disposed at 
an angle of approximately 45.degree. to the box side walls. Such would not 
accommodate boxes of varying sizes. U.S. Pat. No. 4,840,001 discloses a 
device for cutting only the tape supporting a box without cutting the box 
ends itself. This device would be inappropriate for boxes which are sealed 
with glue. U.S. Pat. No. 5,201,788 pertains to a device for cutting off 
the upper portion of a bottle and does not suggest usefulness for cutting 
boxes. 
Since book packages are not of uniform size, the package presented to 
cutting machinery is often slashed too deeply thus irreparably damaging 
the contents. It has been found that by providing a box cutting apparatus 
with a blade which attacks the box parallel to and spaced from the plane 
of the book contents, that cutting damage is greatly reduced. If a blade 
penetrates the box at a depth greater than actually desired, the blade 
merely passes along side the book and does not damage it. 
Typically boxes which are to be opened are constructed of corrugated 
paperboard. It has been found that during the shipping process, the 
corrugated materials often becomes warped. While the major panels of the 
corrugated materials were originally parallel and perpendicular to the 
planes of the book contents, the handling process often causes bending, 
twisting and or other distortions such that they are no longer perfectly 
square with the book planes. Thus, when a blade confronts the box parallel 
to the largest panel plane, there is still a risk of the box being 
improperly cut. However, corrugated boxes are extraordinarily strong and 
resistant to warping at its edges, corners and folds. The invention 
therefore provides an apparatus and method of cutting boxes parallel to 
and spaced from the plane of book contents and wherein the cut is made 
along a folded edge of the box from one corner to an adjacent corner of 
the box. It has now been unexpectedly found that when a box is cut in such 
a fashion, that boxes are reliably opened without damaging the contents. 
SUMMARY OF THE INVENTION 
The invention provides an apparatus for cutting open a sealed box, which 
box has a plurality of planar panels each having a thickness, which panels 
meet at a plurality of edges to define a box length, width and height and 
a central cavity, which comprises means for conveying a box to a cutting 
station; and a cutting station which comprises means for causing a 
rotating blade to cut through an edge and pierce parallel to the plane of 
and into the thickness of one of the planar panels without entering the 
central cavity; and means for urging the box against the rotating blade. 
The invention also provides a method for cutting open a sealed box, which 
box has a plurality of planar panels each having a thickness, which panels 
meet at a plurality of edges to define a box length, width and height and 
a central cavity, which method comprises conveying a box to a cutting 
station and urging the box against a rotating blade at the cutting station 
by causing the rotating blade to cut through an edge and pierce parallel 
to the plane of and into the thickness of one of the planar panels without 
entering the central cavity.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows a typical packaging box which is useful for mailing books. 
Almost all books mailers in use today are of the wrap around type which 
include a glue flap 2 which is wrapped around the bottom panel 1 of the 
carton and glued to the bottom panel to secure the contents of the 
package. FIG. 2 shows a schematic representation of existing 
semi-automatic cutting device which conveys the mailer with the glue flap 
down over a knife blade 3 driven by motor 5 via shaft 4. The knife blade 
moves at a speed higher than the traveling speed of the carton and is 
intended to cut perpendicularly through the glue flaps without penetrating 
through the bottom panel of the carton and possibly damaging the book 
contained in the carton. Because of the needed accuracy of the cutting 
depth combined with the frequent warp of the carton along the glue flap, 
this cut is frequently imperfect. Portions of the cardboard material often 
remain connected and operators must manually complete the cutting 
procedure. FIG. 3 shows an apparatus according to the present invention. 
Shown is a box having a bottom panel 1 and glue flap 2 wrapped around the 
carton and glued parallel to the plane of bottom panel 1. Boxes are 
positioned by conveyor rollers or belts 9 to a cutting station. The carton 
is guided along a side stop 6 which assures consistency of cut depth once 
the cutting blade has been adjusted to the desired depth. A spring loaded 
back stop 7 presses the box along side stop 6 during cutting. Spring 
loaded top rollers 8 assure flat and tight compacting of the box to 
conveyor rollers 9 so that the vertical height of the cut remains 
constant. As shown in FIG. 3, a motor 5 drives shaft 4 and cutting blade 
3. The shaft is positioned vertically as shown. A knife or saw blade, such 
as a carbide tipped knife or saw blade of suitable cutting quality is 
mounted horizontally rather than vertically with respect to the largest 
plane of the book, the plane of the largest box panel and glue flap 2. 
This arrangement allows variations in the cut depth because the bottom 
panel shields the contents from the cutting knife. Optionally, the cutting 
station may have a vacuum line 10 which is suitable for removing dust 
resulting from the cutting. 
In operation, a box is positioned by conveyor rollers 9 to a cutting 
station where it is guided along a side stop 6 by spring loaded back stop 
7 which presses the box along the side stop during cutting. Spring loaded 
top rollers 8 press the box against conveyor rollers 9. Motor 5 drives 
vertical shaft 4 and horizontal cutting blade 3. The blade cuts a folded 
edge of the end glue flap and pierces parallel to the plane of and into 
the thickness of one of the planar panels without entering the central 
cavity. As shown in FIG. 3, blade 3 enters the carton parallel to and 
through either glue flap 2, bottom panel 1 or between the glue flap and 
the bottom panel. This configuration allows cutting boxes of a wide 
variety of dimensions since the top rollers self-correct for box height 
and for any warping of the bottom panel. The back stop and side stop 
self-correct for box width any side panel warping. This provides a 
90.degree. edge for cutting at all times and allows the blade to traverse 
cleanly parallel to the plane of the bottom panel and into the thickness 
of the glue flap or bottom panel. Since the blade is positioned such that 
it never enters the central cavity of the box, it can cut deeply into the 
bottom panel or glue flap thickness and never damage the box contents.