DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0080] While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated.

[0081] A plastic pallet assembly 10 typically includes three major components: a generally rectangular or square bottom deck or base 12; a generally rectangular or square top deck 14, and a plurality of columns or connectors 16 connecting the bottom deck 12 to the top deck 14. The connectors 16 are typically placed in the corners 18 of the assembly 10. Additionally, for larger pallet assemblies, connectors 16 are placed along the perimeter of the assembly midway between the comers 18, and sometimes in the interior of the assembly (i.e., the center of the pallet assembly). As shown in FIG. 1, the connectors 16 are spaced so as to allow the first and second tines 20, 22 of a forklift 24 to be inserted into channels created between the connectors 16 to allow the forklift 24 to lift the pallet assembly (and the contents placed on the assembly).

[0082] In addition to the first and second tines, certain forklifts also include first and a second grabber arms 26, 28 positioned between the first and second tines 20, 22. The grabber arms are able to grip a two-by-four wood beam, and are particularly useful for preventing the pallet from slipping away, especially when a worker is standing on the top of the pallet to handle products high on a storage rack. Such pallets typically were constructed of a plurality of boards forming a top deck connected to a plurality of boards forming a bottom deck or base by three or more two-by-four beams. The grabber arms could engage and hold onto a center beam. This would stabilize and secure the pallet.

[0083] For plastic pallets, the central post or connector is conventionally designed with a wide body for strength and general purposes. For example, a typical 40″×48″ plastic pallet would have a central post or connector with a width of 6″ to 8″. Plastic pallets are usually made of commodity plastic material such as High Density Polyethylene and Polypropylene which are not as strong as higher grades of plastics. Plastic pallets also need to be constructed with generally uniform and thin walls. They normally can not have a thick wall like a two by four wood board because: (1) a thick wall will greatly prolong the molding process hence the cost; and (2) a thick wall will have void and sink marks unless otherwise dealt with. The wall thickness on a conventional plastic pallet is usually between ⅛″ to ⅜″. Challenges therefore exist for a center post, most likely a narrow one such as less than 2″, being a part of a plastic pallet, made of plastic with fairly uniform and thin walls, being strong enough to endure the tough grabbing and twisting of the metal grabber arms which often have teeth, withstanding concentrated load, yet economical enough so as not to increase the total cost of the plastic pallet significantly.

[0084] One economical way of making a plastic pallet with such a center post is to make the post being a removable part. Therefore, the post and the rest of the plastic pallet can be made with two different materials and different processes. Such removable posts or connectors on a plastic pallet are covered by patents by Pigott, et al., under U.S. Pat. No. 4,843,976, U.S. Pat. No. 5,197,395, U.S. Pat. No. 5,579,686, U.S. DES. Pat. No. 398,731; CANADA 1,330,958; AUSTRALIA 650,837, EPO 0,583,796, EPO 0,796,203 etc. Improvements are made in designing a center post or connector suitable for the grabber arms on the forklifts.

[0085] One attempt to take advantage of the use of the grabber arms for plastic pallets is shown in FIGS. 3-5. These Figures disclose a solid plastic connector 30 having a generally rectangular block 32 positioned within a groove 34 of a platform piece 36. The block 32 and platform piece 36 were secured to the top and bottom decks 14, 12 of a plastic pallet assembly by a metal bolt 38. A hole 40 was provided in the block 32, which matched a hole 42 in the platform piece 36 to accommodate the bolt 38. The block 32 was sized to resemble a two-by-four wood beam and functioned in a similar manner to the wood beam to allow the grabber arms 26 and 28 to engage the connector 30 and assist in lifting and stabilizing the pallet assembly.

[0086] Another attempt of providing a center connector sized to allow the grabber arms to engage the connector is shown in FIGS. 6-29. The connector 44 is also formed from a solid block of plastic. The connector 44 includes recesses 46 in the side wall to allow the grabber arms, or extensions from the grabber arms, to obtain a secure grip on the connector 44. The connector also includes braces 48 extending upwardly from the top surface of the connector and downwardly from the bottom surface of the connector. The braces engage and hold onto rib portions in the top deck and bottom deck, respectively, to provide a more secure pallet assembly to inhibit twisting of the center post or connector 44 by the grabber arms with respect to the top deck and the bottom deck.

[0087] Both of these designs were formed from solid blocks of plastic machined to the appropriate dimensions. Additionally, both designs utilize bolts to secure the connectors to the top and bottom decks of a pallet assembly.

[0088] As shown in FIGS. 30-34 a further improved connector is in the form of a molded plastic connector 50. The connector 50 includes a first side 52, an opposing second side 54, a first end 56 and an opposing second end 58. The connector 50 further includes a top surface 60 and a bottom surface 61 (the bottom surface is shown in the bottom plan view of FIG. 33). The top surface 60 further includes an integrally formed, flexible first flange 62 having a hook 64 and an integrally formed, flexible second flange 66 having a hook 68 extending upwardly from the top surface 60. The first and second flanges 62, 66 engage abutments in a top deck 78 of a plastic pallet assembly and are used to connect the connector 50 to a top deck. Similarly, the bottom surface includes an integrally formed, flexible first flange 70 having a hook 72, and an integrally formed second flange 74 having a hook 76 extending downwardly from the bottom surface 61. The first and second flanges 70, 74 extending from the bottom surface 61 engage abutments 79 in a bottom deck of a plastic pallet assembly and connect the connector 50 to the bottom deck 80. A connector 50 connecting a top and bottom deck of a plastic pallet assembly is shown in FIG. 36. FIG. 35 shows the connection of the connector 50 to the bottom deck 80. The abutment 79 in the bottom deck is similar to the abutment in the top deck (not shown).

[0089] The top surface 60 of the connector 50 further includes a first brace 82 extending upwardly from the top surface 60, and an opposing second brace 82 also extending upwardly from the top surface 60. The first and second braces are separated by a channel 86, and are preferably positioned proximate the first end 56 of the connector 50. The top surface also includes a third brace 88, and an opposing fourth brace 90 separated by a channel 92, extending proximate the second 58 of the connector 50. The braces are designed to engage or surround rib portions on the lower surface of the top deck 78 to inhibit twisting of the center post or connector 50 by the grabber arms with respect to the top deck 78 and the bottom deck 80 of the pallet assembly. Similarly, the bottom surface 61 includes a first brace 94, an opposing second brace 96 separated from the first brace 94 by a channel 98 extending downwardly from the bottom surface proximate the first end 56 of the connector 50, and a third brace 100, an opposing fourth brace 102 separated from the third brace 100 by a channel 104 extending downwardly from the bottom surface 61 proximate the second end 58 of the connector 50. The braces extending from the lower surface 61 engage or surround portions of ribs extending upwardly from the top surface of the bottom deck 80, and similarly help prevent twisting of the center connector 50.

[0090] The connector 50 shown in FIGS. 30-36 includes strengthening ribs 106 extending outward from a central portion toward the first side 52 and the second side 54 of the connector 50. Alternatively, the connector 50 can be molded top to bottom and have ribs extend up and down from a central portion.

[0091] The connector 50 also includes a first platform portion 106 generally extending outward from the first side 52 proximate the lower surface 61, and a second platform portion 108 generally extending outward from the second side 54 proximate the lower surface 61. The first and second platform portions are preferably in the shape of the outline of prior connectors (such as that shown in FIG. 11 of U.S. Pat. No. 5,579,686). The platform portions 106, 108 thus fit into abutments or other structure in the bottom deck designed to hold such prior connectors, and provide further support for the connector. The connector 50 of the present invention does not necessarily have to include the platform portions.

[0092] The connector 50 has a generally rectangular shape and is sized to enable the grabber arms of a forklift to engage and hold the connector 50. Preferably the connector 50 has a width of approximately two inches (to resemble a two-by-four wood beam). However, the width can be modified to accommodate the space between the grabber arms of different designs.

[0093] Additionally, the connector can be provided with recesses in one or both of the first side 52 and the second side 54 to accommodate features on or extending from the grabber arms to facilitate a secure grip by such arms.

[0094] Specifically, FIGS. 37-39 disclose various grabber arm configurations and extensions. Referring to FIG. 38, a forklift 110 includes a first grabber arm 112 and an opposing second grabber arm 114 disposed between a first tine 116 and a second tine 118. The first grabber arm includes a contacting member in the form of a projection or teeth 120 at a distal end of the arm 112. Similarly, the second grabber arm 114 also includes a projection or teeth 122 at a distal end of the arm 114. To accommodate this configuration, the connector 50 can be provided with recesses 126 on the first and second sides 52, 54 sized to accept and hold the projections 120, 122. Preferably, each side 52, 54 of the connector 50 includes two such recesses so that it does not matter which end 52, 54 is placed proximate the perimeter of the assembly to allow for ease in installation.

[0095] Referring to FIG. 37, the forklift 110 includes a first grabber arm 120 having a half moon flange 124 extending from the side of the arm 112. The half moon flange can be spring loaded and biased outwardly to place pressure on objects between the first and second grabber arms 112, 114. The connector 60 can be provided with a recess sized to accept and hold the flange 24 to provide a more secure grip on the connector 50.

[0096] Referring to FIG. 39, the forklift includes a first grabber arm 112 with a flange or cam 126, and a second grabber arm 114 with a flange or cam 128. Again, the connector 50 can be provided with appropriately sized recesses to provide for a more secure grip from the grabber arms.

[0097] The embodiment described in FIGS. 30-36 provides several advantages over the solid block plastic pallet center pallet connectors. By providing integral flange connection pieces, the connector 50 can be snap-fitted to the bottom and top decks. This allows for greater speed and flexibility in installation. Additionally, such connectors are less costly because no bolt is required (which also reduces the number of parts that must be kept tracked of) and less plastic is used in the molded pieces. It also facilitates recycling of the plastic pallets without metal parts involved. Moreover, molding is less costly than machining the plastic block connectors.

[0098] In another embodiment, another central connector 130 is shown in FIGS. 40-42. The connector is a generally block shaped piece having a first side 132, an opposing second side 134, a first end 136, and an opposing second end 132. Again, the connector is sized to allow the grabber arms (and any extensions thereof) to grip and hold the connector 130 when utilized with a forklift lifting a pallet assembly including such connectors 130.

[0099] Referring to FIG. 42, the connector 130 is shown as part of a top deck 78 of a pallet assembly. The connector is generally hollow and includes a plurality of supporting and strengthening ribs 140 extending from one side of the interior of the connector 130 to the other. Rectangular shaped compartments 142 are formed between the ribs 140. The connector includes a scalloped outer surface 144 for obtaining a better grip on the connector 130 by the grabber arms.

[0100] A plurality of cross-ribbed supports 146 are shown as part of the bottom deck of a pallet assembly in FIG. 43. These supports 146 are positioned within the compartments 142 of the connector 130 as shown in FIG. 41, and provide additional support against the compressive forces of the grabber arms. By separating the center connector into two portions, an outside shell and an inside support, they can be molded with fairly uniform and thin walls, also with relatively larger spaces between the ribs which are better for molding purposes. Yet, after assembly, they form a very strong structure by inserting one into another so as to provide support to the side wall with reduced spaces. Bonding means such as adhesives, snap-fitting, bonding, fastening or welding can be used to join the two parts together.

[0101] The connector 130 and supports (if utilized) 146 can also be separately molded plastic pieces that are subsequently connected to the bottom and top decks of a pallet assembly by bonding means such as adhesives or welding. Additionally, the connector 130 can also include flanges extending from the top and bottom of the connector 130 for snap-fittingly connecting the connector to the decks. In another embodiment, a separate sleeve 148 can be placed around the outside of the connector 130 to provide additional wear resistance and support. The sleeve can be the same material as the base plastic pallet. However, the sleeve is preferably made from a different material that is tougher and more durable than the typical plastic pallet material, such as some of the engineering thermoplastic resins, rubber, or metal. The sleeve can be made with an extrusion process that is more economical than the molding processes used to create the top and bottom decks of the pallet assembly. A separate sleeve over an inner post is the second way of making the grab-on post with a different material and a different process than the pallet main body itself. Alternatively, the sleeve can be made in multiple pieces and served as side covers that join the center post. For instance, two separate covers can be snapped from the sides onto the center post which can be provided with recesses for the snap-on hooks. The benefit for this embodiment is that the covers can be replaced after wearing and tearing without dismantling the pallet or the center post. Other methods of bonding such as welding, fastening, adhesion and inserting can be used.

[0102] In another embodiment, the center grab-on post is designed for a welded plastic pallet in which the pallet has a deck made of two parts, an upper deck and a lower deck, and a base. All three parts are welded together at a common welding line. The central connector is in the form of an integrally formed post extending from one of the top deck or the bottom deck of the pallet assembly, and an integrally formed sleeve extending from the other deck. An integrally formed post can extend upward from a bottom deck of a pallet assembly. The post is welded to a portion of an upper deck. A plurality of ribs or cross-ribs can extend across the interior of the post to provide additional strength and support. The top deck can further include an integrally formed sleeve extending downward. The sleeve can be aligned with and positioned to cover the post. The sleeve can be sized to allow the grabber arms of a forklift to engage and hold the connector. The distal end (i.e., from the top deck) of the sleeve can be configured to fit into a well formed in the bottom deck.

[0103] Another embodiment of a center connector configured to be held by the grabber arms of a forklift is shown in FIGS. 47-53. FIG. 47 shows the connector 170 between partial cut-outs of a top deck 78 and a bottom deck 80. In this embodiment, the connector 170 is integrally formed (i.e., molded) with the bottom deck 80 and is preferably snap-fittingly secured to the top deck 78. However, this arrangement may be reversed and the connector can be integrally formed with the top deck 78 and then snap-fittingly secured to the bottom deck.

[0104] The connector 170 includes a main body 172 configured in a generally rectangular block shape adapted to be held by the grabber arms of a forklift. As shown in FIG. 48, the top of the connector 170 includes a first and a second flange or hook 174 and 176 for snap-fittingly connecting the connector 170 to the top deck 78. The flanges 174, 176 fit into slots 178, 180 in the top deck 78. Each slot 178, 180 includes a seat 182, 184 (also shown in FIGS. 51 and 52) for engaging a projection 186, 188 on the flanges 174, 176. A well 189, 191 is provided for each flange 174, 176 to allow for a mold piece to form the undercut portion of the projections 186, 188.

[0105] The top of the connector 170 also includes a first and second brace 190, 192 positioned proximate a first end 194 of the connector 170, and a third and fourth brace 196, 198 positioned proximate a second end 200 of the connector 170. As shown in FIG. 53, the braces 190, 192, 196 and 198 fit between ribs 202 in the top deck 78 (the top surface of the top deck 78 is not shown in FIG. 53 for clarity). The ribs 202 hold the braces in place and inhibit twisting of the connector 170 especially the hooks 174, 176 which are the weakest links about the decks 78, 80.

[0106] Similar to some of the other embodiments, the sides of the body 172 of the connector 170 may include recesses 204 to facilitate gripping of the connector 170 by the grabber arms or extensions from the grabber arms.

[0107] FIGS. 54-60 show another embodiment of a center connector 210 integrally formed with a bottom deck 80 of a pallet assembly (again, the structure can be reversed, and the connector be integrally formed on the top deck). The connector 210 includes an integrally formed body 212 (i.e., with the bottom deck 80—best shown in FIG. 59) surrounded by a protective sleeve 214. The protective sleeve 214 can be made of a tougher plastic than the typical plastic used to form the bottom deck 80 and connector body 212, and is replaceable when damaged or worn from use. The sleeve 214 is preferably made by an extrusion process; however, it may also be made by injection molding.

[0108] The body 212 of the connector includes a first well 213 and a second well 215, connected by a bridge segment 217. The top of the body 212 includes a first, second, third and fourth flange or hook 214, 216, 218 and 220 integrally formed with the body 212. The flanges include projections 230, 232, 234 and 236 which fit into slots 238, 240, 242 and 244 of the top deck 78, and abut seats 248, 250, 252 and 254. Unlike the prior embodiments, the projections of the flanges are directed toward the sides 222 and 224 of the connector rather than the ends 226 and 228. This is because the shape of the body 212 and the placement wells 213 and 215 inhibit positioning the flanges in other positions.

[0109] As shown in FIG. 57, the top deck 78 includes ribbing 256 configured to enclose and hold onto the outer edge of the top portion of the body 212 of the connector 210. The sleeve 214 is not shown in the view of FIG. 57 for clarity purposes only. The sleeve 214 should be formed to have a height which is slightly less than the height of the body 212 so the body 212 can be held and supported by the ribbing 256. Alternatively, the sleeve 214 can be formed with the same height as the body 212, and the ribbing 256 can be configured to enclose and hold onto the outer edge of the top portion of the sleeve 214. In either case, the ribbing 256 inhibits twisting of the connector, especially the hooks, about the deck and the base of the pallet. The base of the pallet can also have a well for the sleeve to sit in. This provides additional support to the sleeve and the post against the twisting.

[0110] In an alternative design, the connectors 170 and 210 can be welded to the top deck rather than secured by the flanges.

[0111] In yet another embodiment shown in FIGS. 44-45, the center post 280 is designed for a welded plastic pallet where the welding line is around the middle of the post. In this embodiment, a first half or portion 282 of the center post is formed as an integral part of the top deck 78, and a second half or portion 282 of the center post is formed as an integral part of the base 80. FIG. 44 shows a portion of the pallet with a center post 280 designed for engagement by the grabber arms. FIG. 45 shows an exploded view of the first and second halves 282, 284 of the center posts before welding. The end surfaces of the partial post are preferably mirror image to each other. They are preferably at the same planes as of the other posts so the welding plane is flat one. A hot plate welding can be used to weld the center and the other posts together. The pallet then becomes an integral part. Other bonding processes can be utilized to join the pallet parts together as well. The interior of each portion 282, 284 may include support ribbing 286 or other support structure. Additionally, as described above with other embodiments, the sides of the center post may include recesses 288 to facilitate gripping by the grabber arms. An optional sleeve can also be used as described above.

[0112] The grab-on center connector or post of the present invention can be a separately-made part or parts. These separate parts can be joined to the main body of the pallet assembly through reversible processes such as snapping, fastening or non-reversible processes such as adhesion or welding. Additionally, the grab-on center post can have a separate sleeve or one or multiple side covers which can be joined to the center post by reversible processes such as snapping, inserting, fastening or non-reversible processes such as adhesion or welding. Alternatively, the grab-on center post can have an outer portion and an inner portion that are inserted into each other. Further, the grab-on center post can be an integral part of the deck and/or the base.

[0113] While specific embodiments have been illustrated and described, numerous modifications are possible without departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying claims.