DESCRIPTION OF THE DRAWINGS
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a perspective view of one embodiment of the present invention;
FIG. 2 is a top view of one embodiment of the present invention;
FIG. 3 is a side elevation of one embodiment of the present invention;
FIG. 4 is a front elevation of one embodiment of the present invention;
FIGS. 5A and 5B are elevation views of an upper stringer and a lower stringer used in one embodiment of the present invention;
FIG. 6 is a detail perspective view of one embodiment of the present invention;
FIG. 7 is an elevation view of a lower stringer used in one embodiment of the present invention;
FIG. 8 is a perspective view of a piece of lumber used in the construction of one embodiment of the present invention.
FIG. 9 is a perspective view of one embodiment of the present invention, with the optional deck installed;
FIG. 10 is an exploded perspective view of one embodiment of the present invention, with the optional deck;
FIG. 11 is a front elevation of one embodiment of the optional deck of the present invention;
FIG. 12 is a side elevation of one embodiment of the optional deck of the present invention;
FIG. 13 is a perspective view of the underside of one embodiment of the optional deck of the present invention;
FIG. 14 is a perspective view illustrating the installation of a repair stringer in one embodiment of the present invention.
FIGS. 15A-15F are process diagrams describing an exemplary method for manufacturing pallets.
FIG. 16 is a process diagram describing an exemplary method for repairing pallets.
DETAILED DESCRIPTION
Several issues arise in the construction of pallets. The first issue concerns the particular characteristics of the lumber chosen as construction material. Certain types of lumber are more economical to manufacture or purchase on the open market than others. However, less expensive lumber is often more difficult to form into a pallet of the necessary dimensions or strength for a given application. The second issue is that of recyclability. A wooden pallet will better resist racking, the torsional displacement of the pallet structure, by nailing the components together. However, the presence of nails makes the pallet less amenable to simple recycling techniques. The third issue is that of maneuverability. Many wooden pallet designs are “two-way,” which allow the fingers of a forklift or other lifting machinery to enter the pallet from only one direction. Some other designs are “four-way,” which allow the fingers to enter the pallet from any side, but some of those designs require the fingers to be set to different widths in order to enter a different side. Yet another issue is that of repairability. The fingers often wound the structural members of the pallet, contacting them in unintended ways and causing damage. Not all pallet designs allow for the pallet to be easily repaired, and instead they must be discarded when any piece of the structure is damaged. Various embodiments of the present invention focus on a pallet constructed out of thin, mutually notched stringers; an optional deck to provide structural support and load distribution; and methods for construction and repair of the pallet.
FIG. 1 shows a perspective view of one embodiment of the present invention. It is understood that the pallet as described by various embodiments of the invention is not limited to particular dimensions, and any suitable size will do. One suitable size includes 48 inches by 40 inches. The pallet is composed of two sets of orthogonally crossing stringers. Such sets of stringers are composed of a set of substantially similar lower stringers 1a-1e and a set of substantially similar upper stringers 2a-2e. The set of lower stringers 1a-1e includes a pair of outer lower stringers 1a, 1e; a pair of inner lower stringers 1b, 1d; and preferably one but possibly a different number of central lower stringers 1c. The set of upper stringers 2a-2e includes a pair of outer upper stringers 2a, 2e; a pair of inner upper stringers 2b, 2d; and preferably one but possibly a different number of central upper stringers 2c.
The lower stringers 1a-1e have notches 3 that allow the fingers of a forklift or other lifting machinery to pass through the pallet. The upper stringers 2a-2e also contain notches 7 that allow the fingers of a forklift or other lifting machinery to pass through the pallet.
The lower stringers 1a-1e and upper stringers 2a-2e fit together such that the ends of the lower stringers create projections 4 that extend past the outer upper stringers 2a, 2e so as to laterally guide the fingers of a forklift or other lifting machinery through the pallet, and such that the ends of the upper stringers 2a-2e create projections 8 that extend past the outer lower stringers 1a, 1e so as to laterally guide the fingers of a forklift or other lifting machinery through the pallet. Notably, the notches 7 in the upper stringers 2a-2e further have slots 13, as visible in FIG. 5A, in which are fastened guide ribs 6 with beveled ends 25. One embodiment of the beveled ends 25 of a guide rib 21 is depicted in more detail in FIG. 6. The guide ribs 6 extend past the outer upper stringers 2a, 2e to vertically guide the fingers of a forklift or other lifting machinery through the pallet so as to reduce damage to the pallet.
The intersections of each lower stringer 1a-1e with each upper stringer 2a-2e are preferably cut into slots 9, 10, 11, and 12, as visible in FIGS. 5A and 5B, so that each joint fits together snugly and the pallet is of the minimum possible height. In one embodiment, the tops of the lower stringers 1a-1e and the upper stringers 2a-2e are flush with one another. In other embodiments, they are not flush.
FIG. 2 shows a top view of one embodiment of the present invention. This view shows the orthogonal relationship between the lower stringers 1a-1e and the upper stringers 2a-2e, and gives a clearer depiction of where the fingers P, P′ of the forklift or other lifting machinery pass through the pallet. This figure also shows the preferable embodiment of the guide ribs 6 as extending past the outer upper stringers 2a, 2e and extending the entire width of the pallet as one continuous piece to reduce damage to any of the upper stringers 2a-2e.
FIG. 3 shows a side elevation of one embodiment of the present invention. The load L is pictured in broken outline sitting on top of the pallet. The guide ribs 6 are shown in their slots 13, which slots 13 are preferably deep enough so that the guide ribs 6 protrude a suitable distance, such as approximately one-sixteenth of an inch past the rest of the notch 7, and vertically guide the fingers P of a forklift or other lifting machinery beneath the upper stringers 2a-2e to reduce damage. The side elevation as illustrated by FIG. 3 also shows the projections 4 guiding the fingers P of a forklift or other lifting mechanism horizontally below the guide ribs 6 and along the lower stringers 1a-1e of the pallet. FIG. 3 further shows the location of one central lower stringer 1c, situated between the two inner lower stringers 1b, 1d.
FIG. 4 shows a front elevation of one embodiment of the present invention. The load L is pictured in broken outline sitting on top of the pallet. The projections 8 are pictured guiding the fingers P′ of a forklift or other lifting machinery horizontally through the notches 3. The fingers P′ of a forklift or other lifting machinery would pass through above the notches 3 to possess the load L, lifting the load L and the pallet as secured by strap S. The front elevation as illustrated by FIG. 4 also shows one central upper stringer 2c, situated between the two inner upper stringers 2b, 2d.
FIG. 5A shows an elevation view of one embodiment of an upper stringer 2a-2e. Upper stringer 2a-2e has two notches 7 at either end, far enough from each end of the upper stringer 2a-2e to leave projections 8. Each of these notches 7 has an outer slot 11 and an inner slot 12, each of which is of such a width as to snugly fit the width of a lower stringer 1a-1e within it. Once assembled, the remaining space in the notches 7 is at least wide enough to admit the fingers of a forklift or other lifting machinery beneath it. Upper stringer 2a-2e further has a set of slots 20, each of which is also of such a width as to snugly fit the width of a lower stringer 1a-1e within it. In one embodiment, each of the slots 11, 12, and 20 extends to a depth of approximately half the height of the upper stringer 2a-2e so that when orthogonally mated with the lower stringers 1a-1e, the upper stringers 2a-2e and lower stringers 1a-1e join to form a structure with a flush top. Each of the notches 7 has an additional slot 13 preferably located at its midpoint. These slots 13 are deep enough so that the guide rib 6 (omitted in this figure, but visible in FIG. 3), when seated in the slot 13, protrudes about one-sixteenth of an inch from the rest of the notch 7; and are wide enough so that the guide rib 6 fits snugly within the slot 13. The rest of the notch 7 is cut to a depth of less than half of the height of the upper stringer 2a-2e, so that when the upper stringers 2a-2e and lower stringers 1a-1e are orthogonally mated, the lower stringers 1a-1e are held in securely by both edges of the slots 9 and 10 but the fingers of the forklift or other lifting machinery can still pass through under the notches 7 and guide ribs 6. All of the upper stringers 2a-2e are preferably of substantially the same shape. This way, if one upper stringer 2a-2e is damaged, it can be replaced by an extra upper stringer 2a-2e or repaired by fastening a repair stringer 5 next to the damaged stringer, as shown shaded in FIG. 1 and further described below.
FIG. 5B shows an elevation view of one embodiment of a lower stringer 1a-1e. Lower stringer 1a-1e has two notches 3 at either end, far enough from each end of the lower stringer 1a-1e to leave projections 4. Each of these notches 3 has an outer slot 9 and an inner slot 10, each of which is of such a width as to snugly fit the width of an upper stringer 2a-2e within it. Once assembled, the remaining space in the notch 3 is at least wide enough to admit the fingers of a forklift or other lifting machinery above it and beneath the top surface of the pallet. Lower stringer 1a-1e further has a set of slots 19, each of which is also of such a width as to snugly fit the width of an upper stringer 2a-2e within it. In one embodiments, each of the slots 9, 10, and 19 extends to a depth of approximately half the height of the lower stringer 1a-1e so that when orthogonally mated with the upper stringer 2a-2e, the upper stringers 2a-2e and the lower stringers 1a-1e join to form a structure with a flush top. The rest of the notch 3 is cut to a depth of less than half of the height of the lower stringer 1a-1e, so that the upper stringers 2a-2e are held in securely by both edges of the slots 9 and 10 but the fingers of a forklift or other lifting machinery can still pass through above the notches 3 above it and beneath the top surface of the pallet. All of the lower stringers 1a-1e are preferably of substantially the same shape. This way, if a lower stringer 1a-1e is damaged, it can be replaced by an extra lower stringer 1a-1e or repaired by fastening an repair stringer 5 next to the damaged lower stringer 1a-1e as shown shaded in FIG. 1 with regard to a damaged upper stringer 2a-2e and described further below.
FIGS. 5A and 5B also show that one embodiment of the lower notches 7, the upper notches 3, and the slots 9, 10, 11, 12, 19, and 20 may have approximately similar dimensions on both the lower stringers 1a-1e and the upper stringers 2a-2e. In such an embodiment where the dimensions of the notches and slots are similar, the same tool may be used to remove material from a piece of lumber to create both the lower stringers 1a-1e and the upper stringers 2a-2e. This may make the construction of a pallet efficient and cost effective. Additionally, the paths created for the fingers of the forklift or other lifting machinery by the lower notches 7 and the upper notches 3 will be spaced the same distance apart. This may be beneficial because the same lifting machinery may be used to lift a pallet from either direction without having to reset the width of the fingers, thus improving the efficiency of use of the pallet.
Some embodiments of the pallet may be flipped over, such that the notches 7 and guide ribs 6 in the upper stringers 2a-2e as visible in FIG. 1 are facing the load instead of facing away from the load. In another embodiment, the pallet contains additional guide ribs orthogonal to the guide ribs described above, and located within additional slots cut into the notches in the lower stringers so as to vertically guide the fingers of a forklift or other lifting mechanism over the lower stringers. FIG. 6 illustrates one such embodiment, in which the guide ribs 6 attached to the upper stringers 2a-2e and the guide ribs 21 attached to the lower stringers 1a-1e are mortised at their intersection 22. These embodiments are not depicted in full, but their creation would be readily apparent to those skilled in the art.
FIG. 7 shows a lower stringer 24a-e of one embodiment of the pallet in which all of the notches 7, 23 open away from the load. This lower stringer 24a-e is similar to the lower stringer 1a-1e depicted in FIG. 5B, and interlocks with the upper stringers 2a-2e, albeit in a different manner as depicted in FIG. 1. Since the notches 23 are located on the edge opposing the outer slots 9, the inner slots 10, and the center slots 19, the forkways formed by the notches 23 will open away from the load. The guide ribs 6 may be situated in either the depicted location in the forkway created by the notches 7, in the forkway created by the notches 23, or in both forkways. This embodiment is not depicted in full, but its creation would be readily apparent to those skilled in the art.
The construction of an embodiment of the pallet may use very lightweight and economical materials in its construction. Recognizing that various embodiments need not be limited to the following materials or dimensions, the preferred material for use to manufacture the stringers is a fast-growth timber product, such as low-grade two-by-fours created from black poplar trees. A squared piece of lumber 17 as shown in FIG. 8, which would have an end dimension of about one-and-a-half inches by about three-and-a-half inches, can be split in three to create three pieces 18 with a cross section of about seven-sixteenths of an inch by about three-and-a-half inches. Each of these pieces can then be used to create a lower stringer 1a-1e or an upper stringer 2a-2e. This is an enhancement over existing products, which are limited to a minimum stringer thickness of eleven-sixteenths of an inch, because it may save on both costs and weight.
FIG. 9 shows a perspective view of one embodiment of the invention with the optional deck 15 installed, and FIG. 10 shows an exploded view of the same. The deck 15 is a flat piece of material, preferably the same material used in the construction of the pallet as mentioned hereinbefore. The deck is useful for several applications, including the manipulation of small materials that the bare skeleton embodiment of the pallet would be unable to support due to their size. The underside of the deck 15 contains mortises 16 which accept the upper edges of both the lower stringers 1a-1e and the upper stringers 2a-2e. This mortising may provide stability to the pallet, helping to prevent or reduce racking. Also, the mortising reduces the height of the pallet when the deck 15 is installed. The deck 15 can be constructed of any suitable material. Plywood is appropriate. The preferred decking material is the same fast-growth timber products used for the stringers, which can be formed into planks to create the deck 15.
FIG. 11 shows a front elevation of the deck 15 designed to fit one embodiment of the invention. This illustration shows the ends of the mortising 16, which, in this view, is arranged to accept the top edges of the lower stringers 1a-1e. The mortising 16 is of an appropriate width to provide a snug fit with the upper edges of the lower stringers 1a-1e and the upper edges of the upper stringers 2a-2e.
FIG. 12 shows a side elevation of the deck 15 designed to fit one embodiment of the invention. This illustration shows the ends of the mortising 16, which, in this view, is arranged to accept the top edges of the upper stringers 2a-2e.
FIG. 13 shows a perspective view of the underside of the deck 15 designed to fit one embodiment of the invention. In this view, the pattern of mortising 16 is apparent, and is shown to match the pattern of the upper surface of the lower stringers 1a-1e and the upper stringers 2a-2e as shown in FIG. 10. The mortising 16 is deep enough in the deck 15 to ensure stability, preferably at least half way through the deck 15.
The pallet should be reasonably stable when assembled due to the snug fit of the notches and mortises. For added stability, it is preferred to use fastening means to reinforce each joint. The preferred means is to glue each joint and each mortise, as this can provide for the easiest recyclability, but other means such as nails or staples could also be used.
FIG. 14 shows a detail perspective view of one embodiment of the invention, and illustrates one embodiment of the installation of a repair stringer. In this illustration, damaged upper stringer 2a′ has sustained an injury D. The repair stringer 5 has similar dimensions to the existing upper stringers 2a-2e, but has extended slots 11′, 12′, and 20′ so as to engage the notches 3 of the lower stringers 1a-1e instead of the respective slots 9, 10, and 19 (visible in FIG. 6B). The repair stringer 5 is dropped into place along the dashed lines, and provides support when attached to the damaged upper stringer 2a′.
FIGS. 15A-15F illustrate a method 15000 for constructing a pallet. From a start block (FIG. 15A), the method 15000 proceeds to a set of method steps 15002, defined between a continuation terminal (“Terminal A”) and an exit terminal (“Terminal B”). The set of method steps 15002 between Terminals A-B describe the processing of pieces of timber to form a first set of long stringers, about 48 inches long, of a pallet.
From Terminal A (FIG. 15C), the method 15000 proceeds to block 15010 where a piece of timber is obtained from a fast growth species of tree. At block 15012, the piece of timber is squared and trimmed, each side of the squared piece of lumber having a suitable width of about 3½ inches and a suitable length of about 48 inches. A saw is provided, the saw having teeth that are arranged to create slots, notches, and rib slots periodically across the piece of lumber. See block 15014. At block 15016, this saw is activated to form slots, notches, and rib slots on the piece of lumber. Next, at block 15018, a saw is used to cut the piece of lumber lengthwise into stringers, each having a suitable width of about 7/16 of an inch, and the method proceeds to exit Terminal B.
From exit Terminal B (FIG. 15A), the method 15000 proceeds to another continuation terminal (“Terminal C”) and an exit terminal (“Terminal D”). The set of method steps 15004 between Terminals C-D describe the processing of pieces of timber to form a second set of short stringers, about 40 inches long, of a pallet. From Terminal C (FIG. 15D), the method proceeds to block 15020 where a piece of timber is obtained from a fast growth species of tree. At block 15022, the piece of timber is squared and trimmed, each side of the squared piece of lumber having a suitable width of about 3½ inches and a suitable length of about 40 inches. The saw from step 15014 is then provided in block 15024, the saw having teeth that are arranged similarly to the saw in step 15014 so as to create slots, notches, and rib slots periodically across the piece of lumber. It will be appreciated by one skilled in the art that the reuse of this saw may result in a similar pattern of slots, notches, and rib slots. At block 15026, this saw is activated to form slots, notches, and rib slots on the piece of lumber. Next, at block 15028, a saw is used to cut the piece of lumber lengthwise into stringers, each having a suitable width of about 7/16 of an inch, and the method proceeds to exit Terminal D.
From exit Terminal D (FIG. 15A), the method 15000 proceeds to another continuation terminal (“Terminal E”) and an exit terminal (“Terminal F”). The set of method steps 15006 between Terminals E-F describe the construction of guide ribs and the assembly of a pallet. From Terminal E (FIG. 15E), the method proceeds to block 15030 where the guide ribs are constructed from a suitable material. Assembly of the pallet begins in block 15032, where the short stringers are arranged with their notches facing upwards. Next, in block 15034, glue is applied to each of the slots in the short stringer, and in the corresponding slots in the long stringers. In block 15036, the long stringers are arranged with the notches facing downward so that the slots interlock with the corresponding upward-facing slots on the short stringers. Next, in block 15038, glue is applied to the guide rib slots on the long stringers, and the guide ribs are put in place. The method 15000 then continues to exit Terminal F.
From exit Terminal F (FIG. 15A), the method 15000 proceeds to a continuation terminal (“Terminal F1”). From Terminal F1, the method 15000 continues (FIG. 15B) to another continuation terminal (“Terminal G”) and an exit terminal (“Terminal H”). The set of method steps 15008 between Terminals G-H describe the manufacture and attachment of an optional deck that can fit over a pallet formed from the first and second sets of stringers. From Terminal G (FIG. 15F), the method proceeds to block 15040 where boards of about ½ of an inch thickness and an appropriate length of about 48 inches are obtained. Next, in block 15042, the boards are glued together to form a thin, flat deck of horizontal dimensions similar to the upper surface dimensions of the pallet and of about ½ of an inch thickness. In block 15044, a mortising tool is provided that is capable of cutting mortises in the deck of an appropriate width of about 7/16 of an inch and an appropriate depth of about ¼ of an inch. The width of these mortises should be appropriate to snugly fit the top edges of the stringers. Next, in block 15046, the tool is activated and mortises are cut in the deck to align with the top surfaces of the pallet. In block 15048, glue is applied to the mortises and to the upper surfaces of the pallet, and the deck is installed. The method 15000 then continues to exit Terminal H, and from Terminal H to a finish block (FIG. 15B).
It will be appreciated by one skilled in the art that instead of obtaining timber from forest land 15010, 15020 and squaring it off 15012, 15022 to obtain the necessary lumber, this process can use lumber of similar dimensions purchased on the open market as time and economics require.
FIG. 16 illustrates a method 16000 for repairing a pallet. From a start block, the method 16000 proceeds to block 16002, where a stringer left over from the manufacture of the pallet is obtained. Next, in block 16004, cutting means such as a saw or chisel are used to extend the slots of the stringer suitably far to engage an opposing notch instead of a slot. Then, in block 16006, fastening means such as glue, staples, screws, or the like are used to attach the stringer to the broken stringer, such that the slots on the stringer engage the opposing notches in the orthogonal stringer. The method 16000 then proceeds to a finish block.
While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.
Patent Application
20080047473
