US20070137533A1

US20070137533A1 - Runner pallet

Info

Publication number: US20070137533A1
Application number: US11/275,156
Authority: US
Inventors: Craig Carson; Donald Andrews
Original assignee: Jeco Plastic Products LLC
Current assignee: Jeco Plastic Products LLC
Priority date: 2005-12-15
Filing date: 2005-12-15
Publication date: 2007-06-21

Abstract

A plastic pallet having a deck and underside with numerous runners having arched members in the base of orifices in the runners. The pallet preferably has a corresponding concave entry in the underside of the deck forming the top of each orifice. The concave entries are substantially equidistant from the arched top portion of the base member. The pallet may include reinforcement bars that are C-shaped with lips on each end, wherein plastic forms around the edges of the lips. The pallet may have a center runner along a center of the underside of the pallet with two side runners each forming a passageway with the center runner so that all four sides of the pallet are accessible through orifices or passageways. The leading edge of the runner may be slightly angled upwardly to improve conveyability. The pallet may have ribs extending from the deck and underdeck channels, which may be reinforced, oriented at approximately right angles from the ribs. The pallet is preferably made of rotationally molded polyethylene with strict tolerances.

Description

BACKGROUND

The present disclosure relates to a pallet having multiple runners with orifices for access by machinery and equipment. More particularly, the disclosure relates to pallet having a member at the base of each orifice that is arched preferably with a corresponding concave entry in the underside of the deck.
Pallets are generally portable platforms for storing and moving cargo, freight or other articles. The articles rest on a substantially planar deck, and the underside generally raises the articles on the deck above the ground and provide access for machinery or equipment that move the pallets. Pallets have developed far beyond the wooden pallets with access for tines of forklifts. Molded plastic pallets have become common for certain uses. Pallets are designed with features that allow the intended machinery or equipment to properly operate with the pallet.
U.S. Pat. No. 6,807,911 and related European Publication EP 1 362 794 A1 disclose a continuous surface, substantially hollow pallet having a deck and an underside. The pallet disclosed in those publications can be a rotationally molded plastic pallet. Rotational molding (also known as rotomolding) allows for hollow, one-piece, unitary construction that can be completely enclosed with a continuous and seamless surface to form strong, durable, lightweight and versatile pallets. Rotationally molded polyethylene (PE) has been proven to be a good material for plastic pallets, and the preferred material is a linear low-density PE (LLDPE).
Rotational molding also allows for metal inserts as integral parts of the pallet. U.S. Pat. No. 6,807,911 discloses reinforcement bars and brackets inside a rotomolded pallet.
U.S. Pat. No. 6,807,911 also discloses underside structural features that function in conjunction with the deck for support and reinforcement when a load is placed on the deck. Aspects of the underside providing support and reinforcement for the deck can be utilized in conjunction with the present disclosure and molded plastic pallets in general.
Further, the deck of the pallet can be ribbed for use with certain machinery and equipment. Although U.S. Pat. No. 6,807,911 discloses a dual entry rib configuration, ribs and deck channels in a single direction are also known across the surfaces of decks of pallets. The ends of the ribs are often tapered to assist with insertion of swords, tines, bars or fingers that move the articles with respect to the pallet.
Pallets are also known to have a runner on opposing sides of the pallet with orifices extending through the runners to accommodate access by moving equipment. Typically, two orifices are formed among three legs. The runners have a substantially flat bottom portion, which allows the pallet to run smoothly on specialized equipment, such as roller conveyors.
Specialized handling equipment and machinery often requires strict tolerances for a pallet. Robotics and high speed equipment dictate the thickness of certain aspects, such as the deck, and require strict tolerances in measurements and deflections for a pallet used with such equipment. Rotomolded pallets can be made to obtain such strict tolerances.

SUMMARY

The present disclosure is plastic pallet having a deck and underside with numerous runners having arched members in the base of orifices in the runners. The underside of the pallet preferably has a corresponding concave entry in the underside of the deck forming the top or peak of each orifice. The concave entries are substantially equidistant from the arched top portion of the member.
The pallet may include reinforcement bars that are C-shaped with lips on each end, wherein plastic forms around the edges of the lips. The pallet may have a center runner along a center of the underside of the pallet with two side runners each forming a passageway with the center runner so that all four sides of the pallet are accessible by machinery or tools through orifices or passageways. The leading edge of the runner may angle slightly upwardly to improve conveyability.
The pallet may have ribs extending from the top surface of the deck and underdeck channels on the underside at the bottom side of the deck with the underdeck channels, which may be reinforced, oriented at approximately right angles from the ribs. This preferably forms a very rigid matrix, regardless of whether machinery or tools are inserted in the orifices of the runner of between the runners through the two passageways.

BRIEF DESCRIPTION OF THE DRAWING

The features of this disclosure and the manner of obtaining them will become more apparent, and the disclosure itself will be best understood by reference to the following description of embodiments of the pallet in conjunction with the accompanying drawings, wherein:
FIG. 1 shows a perspective view of a pallet having multiple runners;
FIG. 2 shows a bottom view of a pallet;
FIG. 3 shows a top view of a pallet;
FIG. 4 shows a side view of a pallet showing an end runner;
FIG. 5 shows an end view of a pallet;
FIG. 6 shows a cross sectional view of a pallet taken along section A-A;
FIG. 7 shows a cross sectional view of a pallet taken along section B-B;
FIG. 8 shows a bottom perspective of a pallet;
FIG. 9 shows a bottom view of a pallet having two runners;
FIG. 10 shows a cross sectional view of a reinforced member taken along section C-C of FIG. 9;
FIG. 11 shows a cross sectional view of a reinforced underside below the deck; and
FIG. 12 shows a cross sectional view of an underdeck channel having two fusion points.

DETAILED DESCRIPTION

While the present invention will be fully described hereinafter with reference to the accompanying drawings, in which particular embodiments are shown, it is to be understood at the outset that persons skilled in the art may modify the embodiments disclosed herein while still achieving the desired results. Accordingly, the description that follows is to be understood as a broad informative disclosure directed to persons skilled in the appropriate art and not as limitations of the present disclosure.
In the Figures, like reference numerals indicate the same elements throughout. FIGS. 1 through 5 show a pallet 10 having deck 12 and an underside 14 with numerous runners (i.e. 16, 18 or 20) with orifices 22 and 24 in each runner. With a preferred third runner 18 running along the center of the underside 14 of the pallet 10, the runners (i.e. 16, 18 and 20) form passageways (i.e. runners 16 and 18 form one passageway 26, and runners 18 and 20 form a second passageway 28) for forklift tines or similar equipment to be inserted into. Thus, all four sides of the pallet 10 are accessible to equipment either through orifices 22 and 24 or through passageways 26 and 28. Typically, two orifices 22 and 24 are formed between end legs 30 and 32 and a center leg 34 that from part of the runner (i.e. 16, 18 or 20).
The pallet 10 can be made of a variety of materials. Ideally, the pallet 10 is made of rotationally molded plastic with the preferred construction being a linear low-density PE (LLDPE). Other plastics employed in rotational molding processes include polyolefin, including the preferred PE and polypropylene (PP), polyvinyl-chloride (PVC), polycarbonates, and nylon. These plastics can be used with a variety of resins and additives to meet particular needs or desires for the pallet 10 and the environment in which the pallet 10 will be used.
The deck 12 and the underside 14 are preferably constructed of a unitary, continuous wall that curves along all edges. The outer surface of continuous wall preferably has no sharp corners.
The runner (16, 18 or 20) has a member 36 with an arched profile underneath the orifices (22 and 24). The top portion 38 of the member 36 is arched above a substantially flat bottom portion 40. The arched profile of the member 36 curves with respect to its longitudinal axis with narrower edges 42 and 44 than center 46 of the member 36. The unique arched runner shape provides numerous advantages. The arched top portion 38 is important to using hand trucks and other equipment with tines that insert into the orifices (22 and 24).
Also, the leading edge 48 of a runner (16, 18 or 20) is ideally angled upwardly (i.e. approximately 100 mm) from the end 50 so that the leading edge 48 is above (i.e. approximately 3 mm) horizontal when the pallet 10 is resting on the floor. The preferred leading edge 48 is inclined approximately three millimeters above the substantially flat bottom portion 40, which allows the pallet 10 to run smoothly on specialized equipment, such as roller conveyors. This slight incline is important for conveyability.
The runner (16, 18 or 20) has a unique steel profile 52 that embeds itself in the plastic. The preferred modified C-shaped bar 52 allows the plastic to form around its edges. The preferred bar 52 has a lip 54 and 56 on each curved end, and the plastic can flow around the lips 54 and 56 that provide a place for the plastic to cling to. The plastic in the molding tool is granular, rather than liquid, so the plastic forms around the bar 52. The bar 52, for example, may be approximately 10 mm by 26 mm with lips 54 and 56 of about four millimeters. The embedded bar 52 effectuates the transfer of loads through the plastic to the bar 52, which is preferably steel. In a runner (16, 18 or 20), the bar 52 is oriented on its horizontal axis. The runner (16, 18 or 20) may have recesses 58 extending inwardly from the substantially flat bottom 40 to both hold the bar 52 in place during molding and to provide structural support. As discussed below, a bar 152 can also effectively handle the load on its vertical axis as used under the deck 12.
The arched shaped top portion 38 or the reinforcement bar 52 also allow for the third center runner 18, which previously was not practical in rotomolding. The center runner 18 adds the benefits of the side runners to the center of the pallet 10. The runners (16, 18, and 20) reinforced with bars 52 are more rigid, stronger and have less deflection than runners without such reinforcement bars.
The runners (16, 18, and 20) are very rigid, and have minimal deflection. The preferred maximum concave deflection for an 800×1200 pallet along the length of the runners (16, 18, and 20) is two millimeters, and the maximum concave deflection is one millimeter. This maximum deflection of a runner (16, 18, and 20) is under a load of 1400 kg (measured between rollers of a conveyor with 60 mm diameter rollers with 180 mm center to center distances.). Larger versions of the pallet may have a greater acceptable deflection.
The deck 12 is comparatively thin per this disclosure and type of pallet. Certain machinery operates best with a narrow deck, and total measurements may be defined by machinery using the pallet. The deck 12 is preferably only 25-30 mm thick from base to the underside of the deck (without the ribs), which is 50% as thick as a normal rotationally molded deck structure. For example, the thickness of the deck 12 can be the thickness of the wall at the base of the deck channel (i.e., several millimeters), the vertically oriented bar 152 (such as approximately 20 mm), and the thickness of the wall beneath the bar 152 (i.e., several millimeters).
The curved concave entry 62 in the underside 14 at the bottom of the deck 12 in the orifice (22 or 24) minimizes deck thickness and allows a hand truck to be inserted into the orifice (22 or 24). The concave entry 62 forms the top of the orifice (22 or 24) in the runner (16, 18 or 20), and the curved concave entry 62 is substantially equidistant to the top portion 38 of the arched member 36. The substantially equidistant surfaces formed by the concave entry 62 and the top portion 38 allow for the orifice (i.e. 22 or 24) to be large enough to accommodate the insertion of equipment parts, and the concave entry 62 allows the deck 12 to be thinner while maintaining a constant sized orifice (22 or 24) to accommodate equipment parts. The arched runner (16, 18 or 20) enhances the inclusion of the reinforcement bar 52 in the wider center portion 46, but has narrower edges 42 and 44 so that the overall thickness of the pallet 10 is minimized.
Underdeck channels 64 may be on the underside 14 at the bottom side of the deck 12 to provide strength and reinforcement. Preferably, the underdeck channels 64 are oriented at right angles (approximately 90 degrees) from the ribs 60 extending from the top surface of the deck 12. This also helps minimize deck thickness. As a result, the underdeck channels 64 have fusion points 66 and 68 at each side of the channel 64, which provides a very rigid matrix, regardless of whether the tines of a forklift are inserted in the orifices (22 and 24) of the runner (16, 18 or 20) of between the runners (16, 18 or 20) through the two passageways (26 and 28). The underdeck channels 64 are also wider, such as between 30-50 mm, so the fusion points 66 and 68 are much stronger. The previous width of underdeck channels was normally 25 millimeters, typically with one fusion point. The bond is much stronger with the wider underdeck channels because there are effectively two fusion points 66 and 68 with a small hollow area 70 in the middle, as shown in FIG. 11.
The ribs 60 are preferably the same width as the channels 72 on the deck 12, such as 25 millimeters for all, with the exception of the center rib, which may be wider for use with certain equipment. The ends of the ribs 60 are preferably tapered.
The color of the pallet 10 is ideally permanent and should reflect infrared light. The pallet 10 may be recognized by machinery using reflecting light sensors. Thus, black and mirror-like surfaces are disfavored.
Molded pallets that cannot meet strict tolerances of precise handling equipment may require alignment sections or grooves in the edge of a pallet. Such alignment sections may be made of different plastic with varying shrink and cure rates and ratios. Also, portions of such alignment sections may need to be grinded away to meet strict tolerances of a pallet. The pallet 10 of the present disclosure is preferably rotomolded of a single plastic to achieve tolerances within two millimeters or less for critical measurements without grinding down portions of the pallet.
The process of rotational molding (also known as rotomolding) allows for hollow, one-piece, unitary outer surface construction that can be completely enclosed with a continuous and seamless surface to form strong, durable, and versatile pallets. Rotational molding also allows for metal inserts (i.e. 52 and 152) as integral parts of the pallet 10. A steel bar (i.e. 52 and 152) can be inserted in the mold to embed itself in the plastic of a runner (i.e. 16, 18 or 20) (horizontally oriented) or in the underside 14 (preferably vertically oriented). The C-shaped bar (i.e. 52 and 152) allows the plastic to flow and form around edges of a lip (54 and 56) on each curved end. The plastic in the rotomolding tool is granular, rather than liquid, so the plastic forms around the bar 52 or 152. The mold may include a portion to form recesses 58 extending inwardly from the substantially flat bottom portion 40 of a member 36 of a runner (i.e. 16, 18 or 20) to assist holding the bar 52 in place. The bar 52 or 152 may also be preheated during processing.
Although preferred embodiments of the disclosure are illustrated and described in connection with particular features, it can be adapted for use with a variety of pallets. Other embodiments and equivalent pallets, runners and reinforcements are envisioned within the scope of the claims. Various features of the disclosure have been particularly shown and described in connection with illustrated embodiments. However, it must be understood that the particular embodiments merely illustrate and that the invention is to be given its fullest interpretation within the terms of the claims.

Claims

1. A plastic pallet comprising a deck and an underside with a plurality of runners, the runners having a substantially flat bottom portion, a plurality of orifices, and a member at a base of each orifice including a section of the substantially flat bottom portion, wherein a top portion of the member is arched.

2. The pallet of claim 1 wherein the underside has concave entries forming peaks of the plurality of orifices, the concave entries are substantially equidistant from the arched top portion of the member.

3. The pallet of claim 1 wherein the top portion of the member arches with respect to its longitudinal axis with narrower edges than a center of the member, further comprising a reinforcement bar in the center of the member.

4. The pallet of claim 3 wherein the reinforcement bar is C-shaped with lips on each end, wherein plastic is formed around edges of the lips.

5. The pallet of claim 1 wherein the pallet is formed with an outer surface of a unitary, continuous wall of plastic.

6. The pallet of claim 1 having runners on each side of the pallet and a center runner along a middle of the underside of the pallet.

7. The pallet of claim 6 wherein the runners form passageways with a first side runner and the center runner forming a first passageway, and a second side runner and the center runner forming a second passageway so that all four sides of the pallet are accessible through orifices or passageways.

8. The pallet of claim 1 wherein a leading edge of the runner is slightly angled upwardly.

9. The pallet of claim 8 wherein the leading edge is inclined approximately 3 millimeters above the substantially flat bottom portion.

10. The pallet of claim 1 wherein the pallet is made of rotationally molded polyethylene.

11. The pallet of claim 1 wherein the runners have deflection along a length of the runners that is less than two millimeters under a load of 1400 kg.

12. The pallet of claim 1 wherein the deck is 25-30 millimeters thick.

13. The pallet of claim 1 further comprising ribs extending from a top surface of the deck and underdeck channels on the underside, wherein the underdeck channels are oriented at approximately right angles from the ribs.

14. The pallet of claim 13 wherein the underdeck channels are between 30 and 50 millimeters wide with fusion points at both sides of the channels.

15. A plastic pallet comprising a deck and an underside with a plurality of runners, the runners having a substantially flat bottom portion, a plurality of orifices between legs, and a member at a base of each orifice including a section of the substantially flat bottom portion, wherein a top portion of the member is arched, the underside having concave entries forming peaks of the plurality of orifices, the concave entries are substantially equidistant from the arched top portion of the member, wherein the member arches with respect to its longitudinal axis with narrower edges than a center of the member with an embedded reinforcement bar in the center of the member.

16. The pallet of claim 15 having a runner on each side of the pallet and a center runner along a center of the underside of the pallet.

17. The pallet of claim 16 wherein the runners form passageways with a first side runner and the center runner forming a first passageway, and a second side runner and the center runner forming a second passageway so that all four sides of the pallet are accessible through orifices or passageways.

18. The pallet of claim 15 wherein the runners have deflection along a length of the runners that is less than two millimeters.

19. The pallet of claim 15 wherein the deck is 25-30 millimeters thick.

20. The pallet of claim 15 further comprising ribs extending from a top surface of the deck and underdeck channels on the underside at a bottom side of the deck, wherein the underdeck channels are oriented at approximately right angles from the ribs.

21. The pallet of claim 20 wherein the underdeck channels are between 30 and 50 millimeters wide with fusion points at both sides of the channels.