GB2214122A - "Carton cutter" - Google Patents

Description

i t) 2 14 12 AL J_ -i.- CARTON CUTTER This invention relates generally to

hand held cutting devices, and in particular to cardboard box cutters.

Hand held knives have been used to open product 5 shipping cartons for many years. Retailers of packaged goods have traditionally depended upon naked razor-sharp blades mounted on a utility handle to open cartons of merchandise. Such conventional carton cutters have been the cause of serious personal injury, as well as costly 10merchandise damage due to the exposed blades. In 1986, for example, the use of conventional utility knives by supermarket employees caused over 100,000 lost time injuries and over $4 billion in merchandise was lost because of damage to product containers during opening of cartons.

15While most of the personal injuries were minor and only a few hours or days were lost, some 5,000 of these injuries were serious, some resulting in permanent disability such as loss of use of fingers, hands and even the loss of sight.

kl- While the principal cause of such injuries has been the exposed blades, other factors which have contributed to such injury and property damage are inexperience, distraction, being' bumped by another employee while using the cutter, improper blade application which causes snagging, hanging or breaking of the blade, uneven cardboard siding, wrist fatigue and attempting to use the cutting blade for a purpore ether than that for whizh it was Intended.

In a conventional knife cutter, a single edged razor blade is fastened onto a handle, with the razor edge extending generally in parallel with the handle. In such arrangements, the blade is always exposed and any contact with flesh will result in injury. For example, injuries 15have occurred as a result of placing the cutter into a pocket or into a toolbox, with finger laceration being caused when attempting to retrieve the cutter. Damage to the blade or personal injury may also occur when such conventional cutters are accidentally dropped.

Injuries also occur when a conventional cutter is used as a general purpose utility knife to perform jobs for which it was not intended, for example, to sharpen a pencil, scrape a window, trim carpet, and scribe a line across a board, just to name a few examples. Moreover, even when 25such a cutter is being used for its intended purpose, it is difficult to control the depth of cut and angle of cut, which can cause the operator to pull harder on the cutter, I- 4 with the result that the blade can come up and out of the carton, and cutting -the operator or a bystander. An unprotected blade can be drawn through a dense area of cardboard and bend and break, with the risk that broken pieces of the blade may fly into the operator's eye.

Control of cutting depth is essential to avoid damaging merchandise within the shipping carton. Additionall,, the life of the blade depends upon the type of cardboard used and the cutting resistance. Cutting resistance is a function of cardboard density and cutting angle. The cutter works most efficiently when pulled quickly across the box with the body of the blade being maintained perpendicular to the cardboard surface, and with the cutting edge of the blade inclined at about 45 degrees 15to the cardboard surface. When using a conventional blade cutter, the operator's wrist must be held in a flexed orientation as the blade is drawn across the box. The combination of the pressure applied, together with the flexure of the wrist to achieve the appropriate drawing 20angle of the blade across the box, has caused lost time as a result of severe tendonitis.

511 According to the present invention, a box cutter having an improved guide plate and handle maintains a constant cutting angle and blade orientation, with the 25operator's wrist being held straight as the cutter blade is drawn across a cardboard box. An elongated handle assembly is mounted onto a guide plate, and includes a cutting blade t retainer which holds the edge of a cutting blade in alignment with the longitudinal axis of the handle. The handle and blade retainer project at a predetermined angle of approximately 45 degrees with respect to the planar 5 surface of the guide plate which engages the cardboard box.

According to the foregoing arrangement, the body of the cutting blade is maintained perpendicular to the plane of engagement of the guide place, and the cutting edge of the blade is maintained at a constant drawing angle of approximately 45 degrees. Because of the fixed angular position of the h- !z--ile relative to the guide plate, the operator's wrist and forearm are held straight as a cutting operation is performed. The work is performed by elbow and shoulder movements, thereby avoiding wrist fatigue. Because 15the orientation of the blade relative to the box surface is maintained constant, uneven blade pull/drag, bending and binding are minimized.

A resiliently deflectable spring safety guerd prevents inadvertent contact with the cutting blade.. A 20strip of spring metal projects below the cutting edge of a blade mounted onto the body of a cutter and presents a protective safety guard which retracts as a box is being cut, and as the cutter is lifted away from the box, the guard shield returns to the blade protection position to 25avoid accidental contact with the cutting blade.

The life of the guard spring is extended by attaching the spring to the guide plate by a stake/dimple 1 k b X_ union. The spring is further stabilized by a bridge overlay formed in the base plate.

1 Proper orientation of the blade relative to the box surf ace is maintained by a guide plate assembly which is formed by two guide plates which are obtusely inclined with respect to each other. In a first embodiment (top cutter assembly) which is adapted for cutting a box along a top edge, the guide plate portions are angularly displaced with respect to each other by an angle of 93 degrees, with the spring shield and cutting blade projecting substantially in a right angle with respect to one of the guide plates.

In a second embodiment (tray cutter assembly) which is adapted for opening the center of'a box, the guide plates are angularly displaced by an angle approximately equal to 174 degrees. That is, the box engaging surface of each guide plate extends at an obtuse angle of 93 degrees with respect to the cutting blade, with the included angle between the two guide plates being 174 degrees.

in each of the foregoing embodiments, the obtuse angular relationship of the guide plates reduces the extent of surface area engagement between the guide plates and the box, while maintaining the cutting blade in right angular relationship with the box surface, thereby reducing frictional resistance and drag.

Moreover, In each embodiment, the guide plates are separated by an air gap, and with the leading edges of the k_ c guide plates being rolled or flared to admit air flow. The air space groove and rolled edge portions permit air to be drawn into the interface between the guide plates and the box, -so that the guide plates ride on a layer of air. The layer-of air reduces drag friction and also serves as a heat transfer medium to transfer heat from the blade and avoid overheating the blade during extended cutting operations.

Additionally, the angularly offset guide plate portions and flared or rolled edge portions accommodate external surface irregularities such as flaps, plastic binding straps, labels, staples and glue deposits.

Other features and advantages of the present invention will be appreciated by those skilled in the art upon reading the detailed description which follows with reference to the attached drawings, wherein:

FIGURE 1 is a perspective view of a first preferred embodiment of a safety cutter which is adapted for edge cutting applications; FIGURE 2 is a front elevational view thereof, 20partially broken away; FIGURE 3 is a right side elevational view thereof, partially broken away; FIGURE 4 is an elevational view, partly broken away and partly in section, which details the spring guard shield 25assembly; 4 FIGURE 5 is a left side elevational view of the safety cutter embodiment of FIGURE 1 with the handleopened; FIGURE 6 is a top plan view, partially in section and partially broken away, which illustrates a blade fastener assembly; FIGURE 7 is a perspective view of a second preferred embodiment of a safety cutter which is adapted to open the center of a box; FIGURE 8 is a front elevational view of the cutter assembly shown in FIGURE 7; and, FIGURE 9 is a bottom plan view of the cutter assembly shown in FIGURE 7.

In the description which follows, like parts are

15marked throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details of the present invention.

Referring now to FIGURES 1-4, a safety cutter assembly 10 is configured and adapted for engaging a corner of a cardboard box to produce a controlled depth cut through the cardboard panel in a line extending in parallel with the corner edge. For this purpose, the edge cutter assembly 10 is provided with a pair of guide plates 12, 14 which are k_ fangularly displaced with respect to each other by an obtuse angle 0. In this preferred embodiment, the displacement angle 0 equals 93 degrees. Additionally, the guide plates 12, 14 have flat planar surfaces 12A, 14A for engaging the marginal edge portions of the side wall panels which are joined along the corner line of the box. Each guide plate has a leading edge 12E, 14E, respectJvely, which are rolled out of the respectivg planes of engagement to permit easy passage of the cutter assembly across an uneven or irregular surface.

The guide plates 12, 14 are integrally formed with blade retainer plates 16, 18, respectively. A blade 20 with a razor edge 20E is clamped between the retainer plates 16, 18 by a fastener 22. The fastener 22 has a threaded bolt 22B, a head 22H, and a threaded cap sleeve 22S. The threaded bolt 22B extends through a central opening on the blade 20. The blade 20 is clamped between the retainer plates 16, 18 and the retainer plates 16, 18 are compressed between the head 22H and the threaded cap sleeve 22S.

According to an important feature of the invention, the retainer plates 16, 18 are joined to an elongated handle assembly 24 which projects at an acute angle e with respect to the planar guide plate surface 12A. In the preferred embodiment, the angle e is the drawing angle of the razor edge 20E, and is preferably equal to 45 degrees. As can best be seen in FIGURES 3 and 4, the longitudinal axis 26 extends parallel with the razor edge 20B, and the drawing 1 It X -g- angle e is maintained constant as the cutter lo is moved parallel to the marginal edge of a box as indicated by the arrow 28. 1 Referring now to FIGURE 4, as the planar surface 5 12A of guide plate 12 is applied to the marginal sidewall edge of a cardboard box M, the blade 20 cuts through the cardboard sidewall M, with the tip of the razor edge 20E extending through the cardboard sidewall by a distance K, with the penetration distance K being less than 1/16th of an 10 inch, the typical clearance between a product container sidewall and the inner sidewall of the shipping container M.

A guard spring 30 extends from a staked mounting connection 32 on the guide plate 12, with a curved arm portion 30A projecting through a window 34 formed in guide plate 12. The ribbon of strip spring metal forming the shield 30 extends sufficiently far from its staked mounting on the top of guide plate 12 to permit full resilient flexing of the safety shield and rotation of the curved arm portion 30A to the flexed position as shown In phantom in FIGURE 4 as the guide plate 12 is pressed downwardly onto the top marginal edge surface of the container sidewall M.

The guard spring 30 is attached to the guide plate 12 by the staked connection 32 which Includes a stake 36 and dimple 38. The anchor end of the guard spring is further 25stabilized by an overlay bridge portion 40. According to this arrangement, flex movement of the spring 30 is X_ decoupled f rom the staked connection, with bending forces being reacted over the wide surface of the overlay bridge 40, rather than being transmitted through the staked connection 32.

Referring again to FIGURES 1 and 2, the cutting blade 20 Is received within a passage 42 defined between the parallel retainer plates 16, 18. Entrance to the passage 42 is enlarged by outwardly flared retainer edge portions 16A, 18A. According to this arrangement, air flow is induced through the passage 42 and across the blade 20 during a box cutting operation. movement of ambient air across the blade 20 transfers heat away from the blade, and thereby dissipating heat build up during extended cutting operations.

is As previously noted, the handle axis 26 extends at an acute angle E?, (preferably 45 degrees) with respect to the flat planar guide plate surface 12A. Because the razor edge 20E of the cutting blade is parallel with the handle axis, the drawing angle e is maintained constant as the guide plate 12 is drawn across the sidewall surface of a cardboard box.

The edges of cardboard shipping containers are slightly rounded, and approximate a right angle along corner edges. According to an important feature of the invention, the side guide plate 14 is canted slightly to produce the obtuse corner engagement angle 0. The canted guide surface t 14A thereby accommodates containers having an irregular corner profile which exceeds a right angle. The guide plate surf ace 14A has minimum contact with all other regular and acute container edge profiles, which does not interfere with the cutting action. The overall level of frictional engagement is reduced because the total area of surface engagement is reduced.

Referring now to FIGURES 1, 5 and 6, the handle 24 is formed in complementary handle sections 24A, 24B which are coupled together for scissor movement about a hinge eyelet 44. According to this arrangement, upon removal of the fastener - 22, the handle portions can be separated as shown in FIGURE 5 to expose a cavity 24C formed in each handle section. The cavity 24C is useful for storage of one or more replacement cutting blades. An identical cavity 24C is also formed in handle portion 24A.

A rectangular alignment channel 46 is formed in blade retainer plate 18 to permit and constrain movement of the cutting blade 20 along an axis which is parallel with the handle axis 26 (FIGURE 3). That is, the channel 46 is dimensioned to receive the cutting blade 20 in nesting engagement within the channel, with the cutting depth of the blade being adjusted by extending and retracting the blade through the channel 46. For this purpose, a rectangular slot 48 is formed within a boss portion 50 in parallel alignment with the channel 46. A corresponding rectangular slot 52 is formed in blade retainer plate 16.

The rectangular slots 48, 50 are coincident with each other when the handle sections are joined together as shown in FIGURE 1. The fastener head 22H is provided with a rectangular neck portion 22N which rides within the rectangular slot 52, thereby providing position adjustment capability for setting a desired position of the cutting blade 20.

To assist the operator in setting a standard cutting depth, a position template T is scribed onto the blade retainer plate 16 in alignment with the adjustment slot 52. Index marks corresponding with various blade exposure depths are appropriately marked, for example zero, 1/8 (single thickness), 1/4 (double thickness), and 3/8 (maximum). Precise depth of cut setting is made possible by a group of circular scribe marks Q superimposed on the depth index marks. According to this arrangement, a desired cutting depth is set by sliding the fastener 22 along the channel 52 until the circular fastener head 22H is aligned in registration with the desired circular index mark Q.

When the desired cutting depth has been set, the blade position is locked in place by tightening the fastener sleeve 22S against the boss 50. The cutting depth and the position of the blade are continuously variable along the slot 52 to accommodate a wide range of cardboard sidewall thicknesses.

A cutting blade is loaded into the cutter by removing the screw fastener assembly 22 and separating the 2 4 1 two handle sections as shown in FIGURE 5. The cutter blade is inserted into a blade indentation 54 formed in the blade retainer plate 18, rolled guide plate the side of guide with the cutting edge 20E facing the edge 12E. An arrow 56 is scribed onto plate 14 to indicate the direction of cutting movement. The arrow 56 may also be used by the operator to confirm the correct orientation of the cutting b] ade 20.

Referring again to FIGURES 2 and 5, the guide plate 14 is laterally offset with respect to the blade retainer plate 16 by an offset of 1/32 inch. The lateral offset is produced by a rolled edge 58 which is co-extensive with the guide plate 14 as can be seen in FIGURE 5.

Referring now to FIGURES 7, 8 and 9, a tray cutter assembly 60 is constructed according to an alternative embodiment of the invention. The tray cutter assembly 60 is adapted for opening the center of a box, and in particular for cutting a taped union of two top flaps. In this embodiment, the guide plates 12, 14 are displaced by an obtuse angle, preferably equal to 174 degrees. That is, the box engaging surfaces 12A, 14A of the guide plates each extend at an angle of 93 degrees with respect to the plane of the cutting blade 20, with the included angle between the two guide plates being 174 degrees.

According to this arrangement, each guide plate is angularly offset by 3 degrees withrespect to the surface of t_ 4- a box. The obtuse angular relationship of the guide plates reduces the extent of surface engagement between the guide plates and the box, while maintaining the cutting blade 20 in right angular relationship with the cutting surface. As a result, frictional resistance and drag are reduced, while the cutting blade 20 is maintained at a desired cutting depth and in right angular orientation with respect to the box surface, end with the drawing angle- 8 of the cutting edge being maintained constant.

it will be appreciated that in each embodiment, the operator's wrist and forearm are held straight as the cutter assembly is drawn across a cardboard box. That is, it is not necessary for the operator to flex his wrist to achieve the appropriate cutting angle or blade orientation, thereby avoiding wrist fatigue and the possibility of tendonitis. Because the orientation of the blade relative to the box surface is maintained constant, uneven blade pull/drag, bending and binding are minimized.

moreover, in each embodiment, the leading edges of 20 the guide plate portions are rolled or flared to admit air flow. Additionally, the obtuse angular arrangement of the guide plates permits air to be drawn into the interface between the guide plates and the box, so that the guide plates ride on a thin layer of air, thereby reducing drag resistance. The flow of air around the blade serves as a heat transfer medium to avoid overheating the blade during its extended cutting operations.

Z C_ It will be appreciated that the guard spring 30 shields the cutting edge of the blade from accidental contact in each embodiment. The guard spring also discourages attempts to use the cutter for purposes other 5 than - for opening cardboard boxes. Also, the top surfaces 12B, 14B of the guide plates shield the operator's fingers from sliding contact against the box, thereby preventing friction burn and chefing.

Although the invention has been described with lo reference to two preferred embodiments, the foregoing description is not intended to be construed in a limiting sense. Various modifications of the disclosed embodiments as well as alternative applications of the invention will be suggested to persons skilled in the art by the foregoing specification and illustrations. it is therefore contemplated that the appended claims will cover any such modifications or embodiments that fall within the true scope of the invention.

Claims (17)

CLAIMS:

1.

combination:

OL A safety cutter assembly a handle; comprising, in 1 a blade retainer attached to said handle; fJ-Ast. and second guide plates attached to said blade retainer assembly, said guide plates being inclined with respect to each other by an obtuse angle.

2. The safety cutter assembly as defined in Claim 1, wherein the longitudinal axis of the handle extends in parallel with the cutting edge of a blade mounted on said retainer, and wherein said handle is inclined by an acute angle with respect to the box engaging surface of one of said guide plates.

3. The safety cutter assembly as defined in Claim 2, wherein said handle is inclined by an angle of 45 degrees.

4. The safety cutter assembly as defined in Claim 1, wherein said guide plates are angularly displaced by an angle of 93 degrees.

5. The safety cutter assembly as defined in Claim 1, wherein the guide plates are angularly displaced by an angle of 174 degrees.

t A; 41 X-

6. A safety cutter assembly as def ined in Claim 1, wherein the leading edge of each guide plate is rolled out of the plane of engagement defined by each quide plate, respectively.

7. A safety cutter assembly as def ined in Claim 1, wherein said handle is formed in two complementary sections, said blade retainer comprising f irst and second retainer plates, and means for clarnping a cutting blade between said retainer plates.

8. A safety cutter assembly as defined in Claim 7, one of. said retainer plates having channel portions defining a rectangular indentation for receiving a cutting blade within said rectangular indentation and accommodating sliding movement of a cutting blade along said channel.

9. A safety cutter assembly as defined in Claim 1, wherein said handle is formed in first and second complementary sections, said complementary sections being coupled together in a hinge union to permit scissor movement of said handle sections, and wherein said retainer assembly comprises first and second retainer plates attached to said first and second handle sections, respectively, each blade retainer plate having an elongaged slot aligned with the longitudinal axis of said handle sections, and including a fastener projecting through said aligned slots for clamping the blade retainer plates together.

10. A safety cutter assembly as defined in Claim 9, said retainer plates being spaced with respect to each JIF -W other on opposite sides of a cutting blade received in said indentation, thereby defining an air flow passage through said retainer assembly and along said blade. 1

11. A safety cutter assembly as defined in Claim 9, the leading edges of said blade retainer plates being flared outwardly, thereby defining an opening in communication with said air flow passage.

12. A safety cutter assembly as defined in Claim 1, wherein one of said guide plates has a window opening, and including a resiliently deflectable spring safety guard mounted on said guide plate and projecting through said window opening, said resiliently deflectable spring safety guard retracting through said window as said guide plate is pressed onto the surface of a box.

13. The safety cutter assembly as defined in Claim 12, wherein said resiliently deflectable spring safety guard comprises a strip of spring metal, and one end of said spring metal strip being attached to said guide plate by a stake and dimple union.

14. A safety cutter assembly as defined in Claim 12, wherein said spring strip is stabilized by a bridge overlay attached to said guide plate.

15. A safety cutter assembly as defined in Claim 1, wherein said handle includes first and second handle sections, and said retainer assembly includes first and 1 Z, second retainer plates, said retainer plates coupling said first and second guide plates to said first and second handle sections, respectively, wherein one of said guide plates is laterally offset with respect to the blade 5 retainer plate to which it is attached.

16. A safety cutter assembly as defined in Claim 1, said blade retainer assembly having an indentation for receiving a cutting blade, arid said blade being moveable I.P extension and retraction through said indentation.

17. A cutter assembly as defined in Claim 16, including an elongated slot formed in parallel alignment with the longitudinal axis of said handle, and a template scribed onto said blade retainer assembly in alignment with said slot, said template having index markings corresponding with predetermined depth of cut exposure positions of said cutting blade.

Published 1989 at The Patent Office, State House, 68171 High Holborn, LondonWClR4TP. Further copies maybe obtained from The Patent Omce. Sasz Jra---: 3t Wu7, C-s, el,'um&on, Xa,-a LATZ, -MO). PrIniod by Multiplex techriques Itd, St Mary Cray, Nent, Con. 1/87