This application is a National Stage application of International Patent Application No. PCT/IB2019/059569, filed on Nov. 7, 2019, which claims priority to Swiss Patent Application No. CH 01413/18, filed on Nov. 15, 2018, each of which is hereby incorporated by reference in its entirety.
The invention relates to a plastic pallet having an upper part and three or more runners.
Pallets are used for storage and transportation of goods. The pallets keep the goods off the ground so that they can be lifted and transported by a lift truck. They usually consist of a flat upper part and, in the case of 1200×800 mm pallets, of three runners, which can be manufactured in one piece by injection molding or in several parts. Multi-part plastic pallets are easier and cheaper to produce and consist, for example, of an upper part and a lower part, which are interlocked and joined together. The lower part usually has three runners and nine feet.
The upper part and the lower part, or the runners respectively, can be joined together by welding, as described in CH702628 or CH685549. When the upper part is welded to the lower part, a bead is formed which must be removed with a milling operation so that the pallet has a smooth surface. This is time-consuming and expensive.
Furthermore, the plurality of parts can be connected to each other via snap locks. GB2421939 discloses a plastic pallet with a flat upper part and a flat lower part as well as nine separate feet by means of which the upper and lower parts are connected to one another, with both ends of the feet being fastened to the upper and lower parts of the pallet by means of snap-fits.
U.S. Pat. No. 5,483,899 discloses a pallet having a lower part and an upper part which can be slid into one another, wherein the lower part of the pallet has ribs with a snap element which is arranged at the upper end of each rib. By means of this snap element at the upper end of the ribs of the lower part of the pallet, the snap-fit connection with the upper part is effected.
A plastic pallet is known from EP2733084 having an upper part and a lower part, wherein the foot elements of the upper part and the lower part can be pushed completely into one another and locked by means of snap-fit connections. The outer area of the foot elements is formed by the runners.
The well-known multi-part plastic pallets have the disadvantage that the connection between the various parts can loosen under continuous load and the upper part separates from the feet or runners.
The present invention is now based on the object of providing a multi-part plastic pallet which allows a connection between the upper part and the runners, wherein this connection withstands the load of the impact of the pallets during transport and the pallet thus has an increased impact resistance and a longer service life.
This object is solved by a plastic pallet having an upper part and runners, wherein the upper part is provided with outer and middle female foot parts and the runners are provided with outer and middle male foot parts. Preferably, the plastic pallet has three runners, each with two outer male foot parts and one middle male foot part. In this case, the male foot parts joined to the female foot parts form foot elements, and the female foot parts of the upper part and the male foot parts of the runners can be attached to each other by means of a snap-fit connection. The female foot parts have an outer wall which encloses the male foot part in each case. The outer wall of the outer female foot part extends over substantially the entire height of the outer male foot part, so that the outer male foot parts of the runners can be pushed completely into the outer female foot parts of the upper part, in such a way that the outer wall of the outer female foot part together with the underside of the runner forms a support surface.
The outer wall of the female foot parts encloses the male foot parts in such a way that the male outer foot parts are fully protected in the event of an impact. The outer wall extends over the entire height of the outer female foot part, preferably substantially around the entire foot element. The entire height means that the outer wall of the outer female foot parts extends from the upper side of the pallet to the underside of the runner, which can be placed on a support surface. Preferably, the outer wall extends around the entire foot element except for a recess for a connecting piece of the runners which connects the outer male foot parts to the middle male foot part. Thus, when the pallet is assembled, the outer wall extends on at least three sides of the outer female foot parts from the upper side of the pallet to the underside of the runner.
The outer wall of the outer female foot part forms a support surface together with the runner. The underside of the outer wall of the outer female foot part is flush with the underside of the runner.
Preferably, the plastic pallet according to the invention has three runners, preferably three longitudinal runners. This is the case, for example, with plastic pallets of the standard size of 1200×800 mm. In this case, the outer male foot parts are inserted into the outer female foot parts and form outer foot elements, which are provided on the short transverse side of the plastic pallet. The middle female and male foot parts, which form the middle foot elements, are preferably provided in the middle of the pallet across the long side.
In another embodiment, the plastic pallet has more than three runners, for example five or six runners. For example, five or six runners are preferred for pallets of size 1200×800 nm. For example, a pallet of this type is possible with five runners, of which three runners extend in one direction and two runners extend in the transverse direction along the sides of the pallet. In another embodiment, the pallet comprises six runners, three longitudinal runners and three transverse runners. In this embodiment, preferably all outer eight foot elements have outer walls which extend at least on the outer side of the foot elements, i.e. on the side which is located at the perimeter of the plastic pallet, over the entire height of the outer female foot parts.
The upper part of the plastic pallet preferably has a flat upper surface. In a preferred embodiment, the upper side has a continuous closed surface. In a further embodiment, the upper part comprises reinforcing tubes which additionally reinforce the upper side of the plastic pallet.
In one embodiment, the female foot parts and the male foot parts have a plurality of ribs extending over the entire height of each foot part. The ribs may have different cross-sections and may be, for example, T-shaped, angled, or rectangular in cross-section. The ribs of the female foot parts and the ribs of the male foot parts can be pushed completely into each other.
Preferably, the male foot parts of the runners have an inner wall with ribs which serve as spacers between the inner wall and the outer wall. These ribs also serve on the one hand as a guide when the runners are fitted together with the upper part of the pallet, and on the other hand they form a gap between the inner wall and the outer wall, which serves as additional impact protection. When the plastic pallet hits an object, the ribs can bend slightly and the distance between the inner and outer walls can be reduced for a short time, which absorbs the impact.
Depending on the desired strength of the connection between the two parts of the pallet, the foot elements may have multiple snap-fit connections. In one embodiment of the invention, each foot element has one or more pairs of snap-fit connection elements, preferably one or two pairs. In one embodiment, the foot elements may also have four pairs of snap-fit connection elements and thus four snap-fit connections, preferably in the case of the outer foot elements of the central runner. The one or more snap-fit connections further increase and secure the strength of the foot elements. A snap-fit connection is a positive connection and is formed by a female and a male snap-fit connection element, which are formed as counterparts. Preferably, the counterparts are formed by a male snap-fit connection element provided with one or two hooks and a female snap-fit connection element with recess to be connected thereto, which snap into each other when they are joined together. Such a snap-fit connection has the advantage that the connection is pressed into each other when loaded, which further strengthens the connection. In addition, this snap-fit connection has a resilient property under load.
In a preferred embodiment, the male foot parts of a single runner can be pushed into the foot parts of the upper part separately from the male foot parts of the other runners. Thus, the three runners are individually insertable into the upper part and the plastic pallet is producible from four pieces. However, it is also possible that the three runners are connected to each other and consist of one piece, so that the plastic pallet can be assembled from two pieces, the upper part and a lower part provided with runners.
The foot parts of the upper part and the foot parts of the runners are preferably integrated in one piece with the upper part and the runner, respectively. This design, together with the snap-fit connection, makes it possible to assemble a pallet from only two or four parts, respectively, and without the use of tools.
When the upper part is brought together with the runners, the male foot parts with the ribs are pushed completely into the female foot parts with the outer wall and ribs, so that their ribs are pushed completely into each other and are arranged parallel to each other over their entire length, wherein the foot elements of the pallet are formed and the inner walls of the male foot part and the outer walls of the female foot part form double walls of the foot elements. The double walls increase the strength of the foot elements so that they are more robust and can withstand impacts from a forklift truck or other objects and can therefore be used for a longer period of time.
The ribbed design of the foot elements allows for easy and quick assembly of the two parts of the pallet, and the snap-fit connection elements allow for efficient locking without the need for a tool.
The arrangement of the pallet according to the invention results in the male foot parts of the runners being protected by the female foot parts of the upper part. During transport, for example on conveyor belts or during transport by forklift trucks, the short transverse sides of the pallet with longitudinal runners frequently collide with objects end must be robust against impacts. The outer foot elements in particular are exposed to strong forces. The outer wall of the outer female foot parts, which extends over the entire height of the outer male foot parts, protects the male foot parts of the runners. When the outer foot elements collide with objects, shear forces are generated which are amplified by the weight of the transported goods on the upper side of the pallet. In the pallet according to the invention, these forces are directed into the ground via the upper side of the pallet and the female foot parts. In this case, the foot elements of the upper part are loaded and not the foot elements of the runners. As a result, the snap-fit connection withstands even strong impacts and does not loosen even under continuous load.
In contrast thereto, in conventional multi-part plastic pallets, the foot elements of the runners are loaded on impact, as described for example In EP 2733084A1. The weight of the transported goods on the upper part creates shear forces during impact which act on the connection between the upper part and the foot elements of the runners and which push the upper part away from the foot elements of the runners. With repeated loading, the connection between the upper part and the runners loosens.
Further advantages of the invention follow from the following description, in which the invention is explained in more detail by means of exemplary embodiments shown in the drawings.
The drawings show as follows:
In the figures, the same reference numerals are used for the same elements in each case, and explanations of a particular reference numeral apply to all figures unless explicitly stated otherwise.
In
The outer wall 7 of the outer female foot parts 4 extends over the entire height of the outer male foot elements 5, so that the outer male foot elements 5 of the runners 3 can be pushed completely into the outer female foot parts 4 of the upper part. Foot elements 8 pushed together in this way have the great advantage that they remain stable in the event of impact against an object and the snap-fit connections do not become detached from one another.
In
In
Although various embodiments of the present invention have been described and shown, the invention is not restricted thereto, but may also be embodied in other ways within the scope of the subject-matter defined in the following claims.
Number | Date | Country | Kind |
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01413/18 | Nov 2018 | CH | national |
Filing Document | Filing Date | Country | Kind |
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PCT/IB2019/059569 | 11/7/2019 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2020/099994 | 5/22/2020 | WO | A |
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International Search Report for International Application No. PCT/IB2019/059569 dated Jan. 23, 2020. |
Number | Date | Country | |
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20220002027 A1 | Jan 2022 | US | |
20220315280 A9 | Oct 2022 | US |