This disclosure relates to pallets, also called skids. More specifically, it is related to devices and methods for reinforcing pallets.
There are many styles of pallets for various applications. While many are made of wood, there are also metal and plastic pallets. Attempts have been made to provide reinforcement structures to standard wooden pallets so that a weak or vulnerable part of the pallet might be strengthened. Nonetheless, many pallets have a short life partially due to mishaps in their use. It is the nature of pallet moving operations that their use is frequently accomplished in a less than careful manner. While there are high-tech pallets composed of reinforced plastic and others with embedded RFID identification, there is a need for devices and methods that can adapt low-tech pallet technology into a long-lived high-tech pallet. There is a need for a better analysis of the common modes of pallet damage along with mitigating solutions. Pallet damage can also lead to damage of the goods the pallet is supporting. This is an even greater economic motivation for solutions that produce more robust pallets economically.
A protective device secured on a tine-accepting face of the pallet addresses the problem of providing a long-lasting pallet in a cost effective manner. The protective devices can have a portion with a depth extending into the pallet that can be effective in supporting the tines of forklifts and other lifting equipment and distributing the resulting forces over a large area. Angled and beveled surfaces can deflect misapplied fork tines. In addition, a pallet protector can have an embedded RFID device.
Some embodiments of pallet protectors are unitary plastic molded parts.
They can be nailed or otherwise affixed to a wooden pallet at a fork-receiving face. A protector can have portions that are dimensional; that is, they have portions that extend into the inner space of the pallet. These protruding structures can take the weight and moment of a pallet and the interaction of tines and pallet spread out forces along a large portion of the pallet.
A first example pallet protector has a generally planar faceplate with a beveled top edge and a segmented bottom edge. There are two entry openings designed to allow tines to enter into the inner space under the deckboards of an attached pallet. Each opening in the protector has a four-sided throat extending into the inner space. Protectors can be designed and sized to protect any of the faces of a pallet that has entry openings or notches.
The left, right, top, and bottom transition portions of the entry to the throat are angled inward from the plane of the faceplate toward the center of the opening.
The rest of the four-sided throat then extends relatively straight back. The throat extends as far back as the back edge of the lead deck board. The upper side of the throat is tapered as it proceeds back into the inner space. The taper is upward from its lower edge to its upper edge.
As will be seen more clearly in later figures, the front of the pallet has some mitered portions that fit the shape of the back of the protector.
The faceplate portion itself protects the lead board from damage by accepting, absorbing and spreading out the force of the forklift hitting the pallet's front surface. If protectors are used on both the front and rear faces of a pallet then banding done in that dimension will not tend to cut into the wood, break the wood, or pull the wood up. An RFID module 220 is shown in an inset region of the faceplate 105.
The front portion of the pallet of
Looking more closely at the hollow protrusion,
There are several typical modes of damaging a pallet. Some of them are described below.
While approaching:
If the tines of the fork are too high as the forklift approaches a pallet they may hit the lead deck board rather than slide into the appropriate opening. An example is seen in
Another mode of damage that occurs as a pallet is being approached can occur when the tines are a proper height but the pallet is not being addressed square on. An exaggerated example is seen in
A pallet jack, unlike a forklift, has tines that also serve as a base and includes wheels. This makes the total height of the fork much greater than that of the tines of a forklift fork. In order to lift a pallet with a pallet jack the large fork is wheeled into the inner space of the pallet and then lifted hydraulically. Hitting or running into the lower lead board with the steel wheel can damage that board.
A forklift or pallet jack approaching a pallet correctly in alignment but at too rapid a speed can cause a straightforward mode of damage. The forklift itself simply bangs into the front of the pallet. In fact, one way to think about the problem is that a forklift almost always damages a pallet, no matter how it enters if it impacts any piece of wood with significant force.
On Lifting:
Another type of damage can occur when the pallet is engaged properly from a left to right dimension and a height dimension but the major plane of the tines of the fork are not parallel to the major planes of the pallet. Specifically take the case that the tines are pointed slightly downward. After engagement, when the pallet is then raised a very large portion of the weight of the pallet and its goods generate a force tending to break or pull the top, front lead board upward.
The present teaching avoids or mitigates the above listed damage modes.
When a fork hits the faceplate in any location the wood is protected from being dented, gouged, and split by the pallet protector's strength. The pallet protector takes the brunt of the force, in part, because it can elastically deform. If the hit is too high, the top beveled edge may cause a deflection, further mitigating any potential damage. The angled transition portions provide for deflection in a left-right or up-down direction when tines hit off-angle but at the correct height.
To provide the feature of spreading and absorbing forces, the portion of the protector where the faceplate transitions to the upper side of the throat should be strong and therefore comprised of a suitable material and preferably thick . However if the upper side of the throat were uniformly quite thick it could interfere with the flat, abutting relationship between the fork's upper surface and the deck's lower surface when under load. Since the upper throat side is relatively short and tapered upwards, the fork can stay parallel to the deck abutting the lower surface of the deck as the wood deflects a small amount under load. This can distribute the weight in a relatively uniform manner.
In the case of a downward angled tine 130 that slides below a lower board, the torque on the lead deckboard 120 that results from attempting to lift is spread out. As seen in
If used with a stringer-style pallet, the first embodiment will not allow standard sized pallet jacks to be used, only forklifts. That is due to the reduced opening height of the stringer-style pallet. A second version allowing pallet jacks to be used with this pallet style is seen in the next set of figures.
This second example embodiment has a faceplate 204 and two three-sided protruding areas 205. The side transition areas are sloped on a compound curve. This is also seen in
The front portion of a wooden pallet adapted to be used with this version is seen in
Versions can have an RFID chip or module 220 included in a small compartment molded into a pallet protector. One possible location is seen in
In
Other usage variation can include protecting all four sides of a pallet with suitable pallet protectors. The first embodiment protector can be used with stringer pallets and the second embodiment can be used with block pallets, particularly they can be used on the sides of a block pallet.
The loading conditions for the upper walls of the throats were 1000N on the to simulate a forklift picking up a loaded pallet. Simulated fixtures preventing vertical movement were purposefully left off to demonstrate the effect of the forces a pallet jack or forklift will generate.
A loading force was also added to the front of the protector in order to simulate frontal impact. The loading force there was 1000N. Some deflection at the bottom of the pallet protector was the result of this, given that a pallet is usually resting on a surface this will not occur under daily use however the illustration is done to determine the amount of usable deflection in the part.
Various degrees of displacement are indicated by topological distortion and by hash marks. Arrows with black shafts and white heads 300 are applied forces and white arrows 301 are the reactive forces from the attached fixture.
Although explained and illustrated with specific pallet types, the teachings herein allow pallet protectors to accommodate many types of pallets including:
1. Single deck (face), flush, nonreversible pallet
2. Double deck (face), flush, nonreversible pallet
3. Double deck (face), flush, reversible pallet
4. Single deck (face), single wing, nonreversible pallet
5. Double deck (face), single wing, nonreversible pallet
6. Double deck (face), double wing, nonreversible pallet
7. Double deck (face), double wing, reversible pallet
8. Single deck (face), single-cantilever top and bottom stringer boards, flush, nonreversible pallet
9. Single deck (face), single- cantilever, single wing, nonreversible pallet
10. Double deck (face), single-cantilever, flush, nonreversible pallet
11. Double deck (face), single-cantilever, single wing, nonreversible pallet
12. Double deck (face), single-cantilever, double wing, nonreversible pallet
13. Double deck (face), double-cantilever, single wing, nonreversible pallet
14. Double deck (face), double-cantilever, double wing, nonreversible pallet
15. Double deck (face), double-cantilever, double wing, reversible pallet.
Various industry standard pallet types, standards, and sizes are enumerated in the Uniform Standard for Wooden Pallets published by the National Wood Pallet Association, Alexandria Virginia. One standard referred to in that document is ISO 6780 titled: Flat pallets for intercontinental materials handling Principal dimensions and tolerances.
a. Some versions of pallet protectors comprise an integrally formed planer faceplate with openings, the openings articulated into a throat extending perpendicular to the plane of the faceplate via angled transitional surfaces on at least two sides providing a funnel structure for an entering tine.
b. Version according to (a) above where there are two holes each with a collar extending a length substantially that of a pallet lead board's width.
c. Versions according to (a) above where the outside measurements of the throat are such as to be fit into the face of a pallet with the outer faces of the collar abutting the inside surfaces of the pallet's lead boards.
d. A method of reinforcing a pallet by installing a pallet protector according to (a) and affixing it by fasteners through the protector's faceplate to the front structures of the pallet.
e. The aspect of (a) above where the protector is molded from plastic.
f. A pallet with at least one pallet protector affixed.
g. A pallet with at least two pallet protectors affixed.
Various materials can be used in the composition of a pallet protector. Factors to be considered include strength, weight, resiliency, and cost. Some materials will provide a great degree of pallet protection than others. Some suitable materials include: Recycled HDPE, HDPE, polypropylene, polyethylene, nylon 6, nylon 6/6, and urethane. Composites and additives of these and other materials including nano particles can provide benefits in some applications. Non-plastic material can also be used if the material has suitable properties of strength and resilience.
These descriptions, figures and examples are intended to be non-limiting and to teach the principles and use. The claim below, in contrast, sets out the invention's metes and bounds. In the claims, the words “a” and “an” are to be taken to mean “at least one” even if some claim wording explicitly calls for “at least one” or “one or more”.
This application is a continuation of a U.S. application Ser. No. 13/586,797 filed on Aug. 15, 2012, which is a continuation in part of U.S. non-provisional patent application 13/294,949 filed Nov. 11, 2011. That application, in turn, claims the benefit of U.S. provisional patent application 61/515,161 filed Aug. 4, 2011, under 35 U.S.C. 119 (e). All of these applications are hereby incorporated herein by reference in their entirety.
Number | Date | Country | |
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61515161 | Aug 2011 | US |
Number | Date | Country | |
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Parent | 13586797 | Aug 2012 | US |
Child | 14162669 | US |
Number | Date | Country | |
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Parent | 13294949 | Nov 2011 | US |
Child | 13586797 | US |