METHOD AND APPARATUS FOR CUTTING STRAPS FROM BOXES

BACKGROUND

The invention relates generally to packaging and, more particularly, to apparatus and methods for removing straps from packages or boxes.

Packages or boxes with lids often have one or more bands or straps surrounding the box to hold the lid in place. Before such a box can be opened and emptied, its straps must be removed. International Patent Application Publication Number WO/2007/ 112740A1 describes a deboxing system that includes a rotating cutter on a horizontally disposed, height- adjustable pneumatic guide beam. The guide beam translates the rotating cutter along a diagonal path across the top of the box to sever its straps. Because the straps lie on the top of the box, the rotating cutter can cut into the box top and damage it while severing the band. And saw dust from the kerf cut in the box top can contaminate the contents. Setting the vertical level of the rotating cutter to sever the band without cutting into the box top is difficult because of the precise positioning required.

Thus, there is a need for a strap cutter that does not cut into a box.

SUMMARY

This need and other needs are satisfied by an apparatus embodying features of the invention for cutting straps from boxes. The strap cutter comprises a rotating cutter and a lifting finger movable with the rotating cutter along a cutting path. The rotating cutter has a peripheral blade that is rotatable about an axis of blade rotation. The outermost extent of the rotating blade defines the cutting radius about the axis of blade rotation. The lifting finger has a distal finger tip that is spaced from the axis of blade rotation by a distance greater than the cutting radius. In this way, the lifting finger is positioned to lift straps away from the boxes before they are cut by the advancing rotating cutter.

In another aspect of the invention, a method for cutting a strap from a box comprises: (a) advancing a rotating cutter along a cutting path on one side of a box with a strap; (b) lifting the strap away from the box as the rotating cutter advances along the cutting path; and (c) guiding the strap lifted away from the box into the advancing rotating cutter to be severed.

BRIEF DESCRIPTION OF THE DRAWINGS

These aspects and features of the invention, as well as its advantages, are better understood by reference to the following description, appended claims, and accompanying drawings, in which: FIG. 1 is a perspective view of a deboxing apparatus having a strap cutter embodying features of the invention;

FIG 2 is an isometric view of a box whose straps may be cut by the strap cutter of FIG. 1;

FIG. 3 is an isometric view of the strap cutter of FIG. 1; and FIG. 4 is a side elevation view of the strap cutter of FIG. 1.

DETAILED DESCRIPTION

One version of a strap cutter embodying features of the invention is shown in conjunction with the deboxing apparatus in FIG. 1. The deboxing apparatus 2 includes a horizontally extending conveyor belt 4 with a number of lateral guides 6. The conveyor belt runs from an entry position 8 for boxes to a strap-cutting station 10 and a lid-removing station

12 to an emptying station 14.

After passing the entry position, the boxes arrive at the strap-cutting station 10. A horizontally disposed, height-adjustable pneumatic guide beam 20 supports a rotating cutter 22. The guide beam is disposed oblique to the direction of belt travel 34. In this way, as shown in FIG. 2, the rotating cutter follows a cutting path 23 parallel to a diagonal of a side of a box 32 to cut through crossed straps 24 or through parallel straps 26 in a single pass.

Details of the rotating cutter are shown in FIGS. 3 and 4. The cutter 22 has a support frame 36 with a top plate 38 that mounts to the guide beam 20. A downwardly extending tab 40 supports a cutter arm 42 at a pivot point 44. A vertical-positioning motor 44 pivots the arm to raise and lower a rotating cutter blade 48 to a selected vertical position. The cutter blade is mounted to the shaft of a cutter motor 50, which is supported in a shaft mount 52.

As the cutter motor rotates the rotating cutter about an axis of blade rotation 54, the outermost points of the cutter's peripheral blade 48 sweep out a circle 56 with a cutting radius R. Supported offset from the blade is a finger assembly 58, which includes a lifting finger 60 and a guard 62. The guard extends angularly upward and outward of the blade to a position forward of the blade advancing along the cutting path 23. The guard prevents severed straps from wrapping around the shaft of the motor and causing it to bind.

The lifting finger 60 extends outward to a distal finger tip 64. The finger tip is spaced from the axis of blade rotation 54 by a distance D greater than the cutting radius R. The side of the lifting finger opposite the blade forms a sliding surface 66 that rides along a side of the box as the rotating cutter advances along the cutting path. Thus, the lifting finger separates the blade of the rotating cutter from a box to prevent the blade from cutting into the box. The lifting finger tapers narrower to the finger tip to form a sloped guide surface 68 opposite the sliding surface. The guide surface guides straps into the blade of the cutter to be severed.

In operation, the rotating cutter is lowered by the vertical-positioning motor 46 to the proper level for the box. The pneumatic guide beam 20 advances the cutter 22 along the cutting path 23. The finger tip 64 of the lifting finger 60 riding along the side of the box hooks the straps, lifts them away from the box, and guides them into the rotating blade 48 as the cutter advances along the cutting path. Once the straps are cut, the box may be conveyed to the lid-removal station 12, where the lid 70 of the box is removed by a suction-cup device 72, and then to the emptying station 14. What is claimed is: