Patent Description:
Conventionally, various pallets have been widely used as goods carrying platforms when carrying goods by forklifts or hand-drawn pallet jacks. For example, when transporting goods by a forklift or the like at a logistics site, the goods are loaded on a loading surface of the pallet, the fork of the forklift is inserted into the fork insertion port on the side of the pallet, and the pallet is lifted to a predetermined height position. After conveying the pallet to a destination by operating the forklift, the fork is lowered, the pallet is placed on the destination, and the fork is extracted from the fork insertion port.

As general pallets, wooden, plastic, metal (iron alloy) or paper pallets are known. However, each of many common pallets has large weight, for example, the wooden pallet weighs <NUM> or more, and even though the paper pallet is lighter than the plastic or metal pallet, such a paper pallet has a considerable weight because it is made through compression forming to have high density to ensure its shape stability.

Related to the above, a pallet made of foamed resin is known as a lighter pallet than the paper pallet (see, for example, <CIT>). However, the pallet made of foamed resin has fine irregularities on the surface due to the foamed beads, and there is a problem that the surface is fragile and rough compared to a pallet made of wood or plastic. Then, such a resin pallet that the surface of the pallet body is covered with a resin sheet for reinforcement is known (see, for example, <CIT>).

<CIT> discloses a pallet having a plate-like pallet body and a plurality of legs provided on a bottom surface of the pallet body. The pallet comprises an exterior shell element formed from thin, lightweight, resinous sheet material and a core element of lightweight, rigid, resinous foam, conforming in shape and substantially filling the interior of the shell to form an upper bearing surface for the pallet. The shell element is vacuum formed as a unitary structure forming an open-topped enclosure with a rectilinear upper perimeter.

Further prior art is known from <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

The foamed beads, which constitute the foamed resin pallet, contain air in their almost entire volume, and therefore have low thermal conductivity and moderate elasticity. Therefore, the pallet made of foamed resin has a thermal insulation performance that makes it difficult for heat from a road surface, a warehouse floor, etc. to be transferred to the pallet, and also since the pallet made of foamed resin has a cushioning property unique to foamed resin, goods-conveyed can be protected from shocks.

However, since the resin sheet has higher thermal conductivity than the foamed beads, heat is easily transferred to the goods-conveyed when the resin sheet is in direct contact with the goods-conveyed. Therefore, as shown in the above-mentioned Patent Document <CIT> <NUM> , although the pallet whose entire surface is covered with a resin sheet is superior in thermal insulation performance and cushioning property than the conventional plastic pallet, however, as compared with those not covered with the resin sheet, there is a possibility that the advantageous functions inherent in the foamed resin such as the above-described high thermal insulation performance and cushioning property cannot be sufficiently exhibited.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a pallet having excellent thermal insulation performance and cushioning property with respect to loaded goods-conveyed while ensuring the strength of the outer surface of the pallet.

In order to solve the above problems, the present invention provides a pallet comprising: a plate-like pallet body made of foamed resin; a plurality of legs provided on a bottom surface of the pallet body; and a resin sheet integrated by vacuum-forming from the bottom surface of the pallet, wherein a top surface of the pallet body has a loading surface on which goods-conveyed are placed, and a step portion formed in a shape down-step from an outer peripheral edge of the loading surface to side surfaces of the pallet body, and the resin sheet covers the bottom surface of the pallet body, the legs, the side surfaces of the pallet body and the step portion, and the loading surface is not covered with the resin sheet.

In the pallet, it is preferable that the portion of the resin sheet covering the step portion is stretched so that the sheet thickness of that portion is reduced.

In the pallet, it is preferable that the pallet body and the legs are molded as separate bodies, and the bottom surface of the pallet body has exhaust holes made in a thickness direction of the pallet body at the positions where the legs are arranged.

In the pallet, it is preferable that the bottom surface of the pallet body has fitting concaves into which the legs are fitted, and the exhaust holes are provided at a peripheral edge of the fitting concaves.

In the pallet, it is preferable that the exhaust holes do not penetrate to the top surface of the pallet body, and a thickness of <NUM> or more is provided from a bottom of the exhaust holes to the top surface of the pallet body.

In the pallet, it is preferable that a ridge line portion between the step portion and the loading surface is chamfered to be a curved surface.

In the pallet, it is preferable that the loading surface is an exposed surface of the foamed resin forming the pallet body and having a thermal insulation performance and a cushioning property.

According to the pallet of the present invention, since the resin sheet covers surfaces that are particularly susceptible to damage, such as the bottom surface of the pallet body, the places between the legs into which the fork are inserted, and the side surface of the pallet body, those outer surfaces can be strengthened. Moreover, since the loading surface of the pallet is not covered with the resin sheet, the foamed resin having the thermal insulation performance and cushioning property and forming the pallet body is exposed there. In other words, the foamed resin constituting the foamed resin pallet can contact directly with the goods placed on the pallet so as to be conveyed, and therefore it is possible to enjoy the high thermal insulation performance and the cushioning property unique to the foamed resin.

A pallet according to an embodiment of the present invention will be described with reference to the drawings. As shown in <FIG>, <FIG>, <FIG> and <FIG>, the pallet <NUM> of this embodiment can be preferably used for the management and transportation of goods using a forklift, a hand-drawn pallet jack or the like at a distribution site or the like. In the following description, the left front side of the pallet <NUM> shown in <FIG> is referred to as the front, and the right front side of the pallet <NUM> is referred to as the right side.

The pallet <NUM> comprises a plate-like pallet body <NUM> made of foamed resin, a plurality of legs <NUM> provided on the bottom surface of the pallet body <NUM>, and a resin sheet <NUM> that covers the outer surfaces of the pallet body <NUM> and the legs <NUM> (see <FIG>). The plurality of legs <NUM> are arranged in a lattice pattern at predetermined intervals on the bottom surface of the pallet body <NUM>. In this example, nine legs <NUM> of <NUM> × <NUM> are provided, each of which has a box-like shape with a substantially square projected area in plan view. In the illustrated example, the resin sheet <NUM> is shown in gray for convenience of explanation, but the resin sheet <NUM> may be transparent or the same white as the pallet body <NUM>.

The leg <NUM> is a support member that raises the height of the top surface <NUM> serving as the loading surface <NUM>, and the plurality of legs <NUM> are arranged at predetermined intervals from the adjacent legs <NUM>, thereby the fork insertion portion <NUM> into which a fork is inserted is formed (<FIG>). In this example, the structure of the pallet <NUM> of so-called four-way insertion is shown, in which the fork insertion portion <NUM> is formed between the legs <NUM> on both sides and the legs <NUM> on center, and the fork insertion portions are opened on four sides, namely, left, right, front and back sides, thus four insertion directions are available. In addition, for example, legs each of which has a long box-like shape with a substantially rectangular projected area in plan view may be provided in a three-row arrangement, and so-called two-way insertion may be possible.

The pallet body <NUM> and the legs <NUM> are molded as separate parts. The material constituting the pallet body <NUM> is, for example, a foamed synthetic resin such as a polyolefin-based resin such as polystyrene, polyethylene, or polypropylene, and in the present embodiment, foamed polystyrene (EPS: expanded polystyrene) is used. The material constituting the legs <NUM> is preferably the same as that of the pallet body <NUM>, but a material different in density and hardness from the pallet body <NUM> may be used, or another material may be used.

As shown in <FIG>, the resin sheet <NUM> covers the bottom surface <NUM> of the pallet body <NUM>, the legs <NUM>, the side surface <NUM> of the pallet body <NUM>, and a step portion described later. Since the legs <NUM> are covered with the resin sheet <NUM> together with the bottom surface <NUM> of the pallet body <NUM>, they are more firmly fixed to the pallet body <NUM>.

As shown in <FIG> and <FIG>, the pallet body <NUM> is a plate-like member having a predetermined thickness and having a rectangular shape in plan view. The pallet body <NUM> of the present example is formed so that the width on the front side (<FIG>) is slightly larger than the width on the side surface (<FIG>), but this is not limitative, instead, the shape of the pallet body <NUM> may be appropriately selected from various shapes including a polygonal shape in plan view. The pallet body <NUM> comprises the top surface <NUM> having a loading surface <NUM> on which goods is loaded, the bottom surface <NUM> on which the legs <NUM> are provided, and the side surface <NUM> connecting the top surface <NUM> and the bottom surface <NUM>. The outer dimensions of the top surface <NUM> and the bottom surface <NUM> are substantially equal, and the corners made of the side surfaces <NUM> are chamfered so as to be rounded (see also <FIG>).

On the top surface <NUM> of the pallet body <NUM>, the step portion <NUM> is provided, which is formed in a shape down-step from the outer peripheral edge of the loading surface <NUM>, on which the goods-conveyed are placed, to the side surface <NUM> of the pallet body <NUM> (see <FIG>). The step portion <NUM> is formed in a region having a width of about <NUM> to <NUM> from the outer peripheral edge (ridge line portion with the side surface <NUM>) of the top surface <NUM> toward the inside. When the width of the step portion <NUM> is too large, the loading surface <NUM> becomes unnecessarily narrow, and when the width of the step portion <NUM> is too small, the resin sheet <NUM> becomes insufficiently wound as described later. Further, the depth of the step portion <NUM> (step difference from the loading surface <NUM>) is preferably <NUM> to <NUM>. If the step portion <NUM> is too shallow, the resin sheet <NUM> may not accurately cover the step portion <NUM>, and if the step portion <NUM> is too deep, surface strength will decrease, because exposed area of the foamed resin in the peripheral edge portion of the loading surface <NUM> increases. The ridge line portion between the step portion <NUM> and the loading surface <NUM> is chamfered so as to be a curved surface (see also <FIG>).

The surface of the bottom surface <NUM> of the pallet body <NUM> is provided with the grooves 22a formed in a lattice shape in order to prevent the inserted fork from slipping. Further, the bottom surface <NUM> of the pallet body <NUM> has the fitting concaves <NUM> in which the legs <NUM> are fitted. Each of the fitting concaves <NUM> is formed so that its inner dimension is substantially equal to the outer dimension of the top surface (joint surface <NUM>) of the leg <NUM>.

As shown in <FIG>, in the fitting concave <NUM> at the center thereof, the fitting convex <NUM> is formed, which is fitted with the fitting concave <NUM> formed on the top surface of the leg <NUM> (see <FIG>). The fitting convex <NUM> is a trapezoidal protrusion whose top portion is slightly smaller than the bottom portion, and the vertical grooves <NUM> are formed on the four side surfaces thereof, and also the ventilation grooves <NUM> are formed on the bottom surface of the fitting concave <NUM> radially from the convex <NUM> at the center. In this example, the ventilation grooves <NUM> are formed so as to extend in eight directions around the fitting convex <NUM>. Further, the longitudinal grooves <NUM> formed on the four side surfaces of the fitting convex <NUM> are connected to the ventilation groove <NUM> on the bottom surface of the fitting concave <NUM>.

Also, the plurality of exhaust holes <NUM> carved in the thickness direction of the pallet body are made on the bottom surface of the fitting concave <NUM>. The exhaust holes <NUM> are provided at the outer periphery of the ventilation grooves <NUM> at the periphery of the fitting concave <NUM>. As shown in <FIG>, the exhaust holes <NUM> do not penetrate to the top surface <NUM> of the pallet body <NUM>, and a predetermined thickness is ensured from the bottom of the exhaust holes <NUM> to the top surface <NUM> of the pallet body <NUM>. The thickness is preferably <NUM> or more, and particularly preferably <NUM> to <NUM>, for example. However, for the vacuum-forming processing of the resin sheet <NUM> described later, the thickness is desirably <NUM> or less.

As shown in <FIG>, the leg <NUM> includes the joint surface <NUM> joined to the pallet body <NUM>, the installation surface <NUM> serving as a bottom surface when the pallet <NUM> is placed, and the side surface <NUM> distributed between the joint surface <NUM> and the installation surface <NUM>. In the leg <NUM> of this embodiment, the joint surface <NUM> and the installation surface <NUM> have a substantially rectangular shape in plan view, and the leg <NUM> has a block shape with four side surfaces <NUM>. The four side surfaces <NUM> have the same shape, and only one side surface is shown in <FIG>.

The leg <NUM> is formed so that the joint surface <NUM> is slightly larger than the installation surface <NUM>, and the side surface <NUM> between them is slightly inclined. The joint surface <NUM> has the flange 31a that slightly extends outward. The flange 31a is fitted into the fitting concave <NUM> of the pallet body <NUM>, and the bottom surface <NUM> of the pallet body <NUM> and the side surface <NUM> of the leg <NUM> are connected to the flange 31a at a moderate angle. Moreover, the flange 31a has the thin part 31b with slightly thin thickness at the location where the flange 31a faces the ventilation groove <NUM> in planar view.

The joint surface <NUM> of the leg <NUM> is provided with the fitting concave <NUM> into which the fitting convex <NUM> of the pallet body <NUM> is fitted. The fitting concave <NUM> is formed so that its inner dimension is substantially equal to the outer dimension of the fitting convex <NUM> of the pallet body <NUM>. The fitting concave <NUM> is formed so that its depth is deeper than the height of the fitting convex <NUM>. In the bottom of the fitting concave <NUM>, the round hole 34a is formed, and further the needle hole 34b penetrating to the installation surface <NUM> of the leg <NUM> is formed in the bottom of the round hole 34a. Therefore, the fitting concave <NUM> communicates with the outside, namely, the installation surface <NUM> side of the leg <NUM> through the round hole 34a and the needle hole 34b. Further, when the leg <NUM> is attached to the pallet body <NUM>, the fitting concave <NUM> communicates also with the exhaust holes <NUM> through the vertical grooves <NUM> on the four side surfaces of the fitting convex <NUM> and the ventilation grooves <NUM> on the bottom surface of the fitting concave <NUM>.

The height of the side surface <NUM> of the leg <NUM> is designed so that the raised amount of the loading surface <NUM> becomes a desired value. In addition, a plurality of ribs 33a are formed in the side surface <NUM> in the vertical direction to improve strength. It should be noted that on the installation surface <NUM> of the leg <NUM> except for the vicinity of the needle hole 34b, a cover or the like (not shown) made of curable resin, wood, metal etc. may be attached in order to prevent the deterioration of the foamed polystyrene and the generation of debris due to a plurality of conveyances using a forklift. In addition, the leg <NUM> is not limited to the illustrated shape, and may be, for example, an elliptical column shape or a polygonal column shape other than such a quadrangular column.

The resin sheet <NUM> is a sheet member that is softened and deformed by heating, cured at room temperature, and has sufficient strength and surface durability against a heavy object placed thereon. As the material of the resin sheet <NUM> of the present embodiment, a resin material made of the same compound as the pallet body <NUM> is preferably used. When the pallet body <NUM> and the legs <NUM> are made of the above-mentioned expanded polystyrene, for example, a high-impact polystyrene (HIPS) sheet is used as the resin sheet <NUM>.

In the pallet <NUM> of this embodiment, the procedure, for integrally forming the resin sheet <NUM> on the pallet body <NUM>, will be described with reference to <FIG> and <FIG>. First, as shown in <FIG>, a pallet body <NUM> molded into a predetermined shape is prepared. The pallet body <NUM> is provided with legs <NUM>. Next, the pallet body <NUM> is placed on the top surface of the vacuum chamber <NUM> so that the bottom surface <NUM> with the legs <NUM> faces upward and the top surface <NUM> having the loading surface <NUM> faces downward, and then the resin sheet <NUM> is placed thereon. The heater <NUM> is disposed above the resin sheet <NUM>, and the heater <NUM> heats the resin sheet <NUM> to soften the resin sheet <NUM>.

The vacuum chamber <NUM> is movable upward with the pallet body <NUM> placed thereon. As shown in <FIG>, when the resin sheet <NUM> is softened, the heater <NUM> is retracted and the vacuum chamber <NUM> (upper table) is pulled up to bring the pallet body <NUM> and the resin sheet <NUM> into contact. The vacuum chamber <NUM> is provided with suction ports (not shown) communicating between the internal space of the vacuum chamber <NUM> and the outside on the top surface side of the vacuum chamber <NUM>, and a vacuum pump for decompressing the internal space. When the vacuum chamber <NUM> brings the pallet body <NUM> into close contact with the softened resin sheet <NUM>, the vacuum pump is operated, as shown in <FIG>, to evacuate the air between the pallet body <NUM> and the resin sheet <NUM>, and the resin sheet <NUM> is vacuum-adsorbed to the pallet body <NUM>.

As shown in <FIG>, the pallet body <NUM> is provided with the exhaust holes <NUM>. The exhaust holes <NUM> can communicate with the fitting concave <NUM> of the leg <NUM> through the ventilation grooves <NUM> and the vertical grooves <NUM>, and the fitting concave <NUM> is connected to the outside of the installation surface <NUM> of the leg <NUM> through the round hole 34a and the needle hole 34b. Although the exhaust hole <NUM> does not penetrate the top surface <NUM> of the pallet body <NUM>, the exhaust hole <NUM> can effectively communicate with the outside of the top surface <NUM> of the pallet body <NUM> through slight gaps between the foamed beads because the thickness of that portion is thin. Therefore, when the vacuum chamber <NUM> is operated to evacuate air from the top surface <NUM> side of the pallet body <NUM> so as to decompress, the air between the top surface <NUM> of the pallet body <NUM> and the legs <NUM> and the resin sheet <NUM> placed thereon is evacuated through the needle hole 34b, the round hole 34a, the fitting concave <NUM>, the vertical grooves <NUM>, the ventilation grooves <NUM>, and the exhaust holes <NUM>. Also, since the thin portion 31b of the flange 31a of the leg <NUM> is thin, the air between the pallet body <NUM> and the resin sheet <NUM> is exhausted through this thin portion, the ventilation grooves <NUM>, and the exhaust hole <NUM>.

Thereby, the top surface <NUM>, the side surface <NUM>, and the outer surface of the legs <NUM> of the pallet body <NUM> are covered with the resin sheet <NUM> without any gap. Further, the resin sheet <NUM> is not coated on the loading surface <NUM>, which is in contact with the upper table of the vacuum chamber <NUM>, however since the step portion <NUM> is slightly separated with space from the upper table of the vacuum chamber <NUM>, the resin sheet <NUM> can enter the space and the step portion <NUM> is also covered with the resin sheet <NUM>.

Subsequently, the operation of the vacuum chamber <NUM> is stopped, the pallet body <NUM> and others are returned to atmospheric pressure, and the pallet <NUM> covered with the resin sheet <NUM> is removed from the top the vacuum chamber <NUM>. At this time, as shown in <FIG>, the portion of the resin sheet <NUM> covering the step portion <NUM> is stretched, and the sheet thickness of that portion is reduced. Finally, a knife or the like is inserted into the gap between the step portion <NUM> and the loading surface <NUM>, and the remaining resin sheet <NUM> is trimmed. In this trimming, since the sheet thickness of the resin sheet <NUM> where the knife is inserted is thin, trimming can be easily performed. Moreover, since the ridge line part between the step portion <NUM> and the loading surface <NUM> is chamfered so as to be a curved surface, it is easy to insert a knife. Thus, a pallet <NUM> can be obtained, in which the bottom surface <NUM> of the pallet body <NUM>, the outer surface of the leg <NUM>, the side surface <NUM> and the step portion <NUM> of the pallet body <NUM> are covered with the resin sheet <NUM>, and the loading surface <NUM> is not covered with the resin sheet <NUM>.

In the pallet <NUM> configured as described above, since the pallet body <NUM> constituting the main body is made of foamed resin, it is lightweight, and since the resin sheet <NUM> is integrally formed on the bottom surface side of the pallet <NUM> by vacuum-forming, compared with the foamed resin constituting the main body <NUM>, more surface durability can be obtained. Particularly, following surfaces are vulnerable to damage: the surface, among the bottom surface <NUM> of the pallet body <NUM>, located between the legs <NUM> into which a fork is inserted; the installation surface <NUM> of the legs <NUM>, which is placed on a hard installation place such as concrete or asphalt; and the side surface <NUM> of the pallet body <NUM> having many opportunities to come into contact with walls and other structures. However, since those surfaces are covered with the resin sheet <NUM> in the pallet <NUM>, the resin sheet <NUM> can reduce the damage of those places and ensure the strength of the outer surface.

Further, the pallet <NUM> is covered with the resin sheet <NUM> up to the step portion <NUM> on the top surface <NUM> side of the pallet body <NUM>. That is, the resin sheet <NUM> is wound up to the part of the top surface <NUM> of the pallet body <NUM>, and therefore, for example, as compared with the case where the resin sheet <NUM> covers only the bottom surface <NUM> of the pallet body <NUM> and the legs <NUM> or at most up to the side surface <NUM> of the pallet body <NUM>, the resin sheet <NUM> is hardly peeled off and the durability of the pallet <NUM> can be improved. Furthermore, since the resin sheet <NUM> covers only up to the step portion <NUM> step-downed from the loading surface <NUM>, as the results, for example, the goods-conveyed placed on the loading surface <NUM> are prevented from coming into contact with the edge of the resin sheet <NUM>, and so the peeling of the resin sheet <NUM> can be further effectively prevented.

As a matter of fact, the resin sheet <NUM> has higher thermal conductivity than the foamed beads, and therefore heat is easily transferred to the goods-conveyed directly contacting with the resin sheet <NUM>. Therefore, if both the top surface <NUM> and the bottom surface <NUM> of the pallet body <NUM> were covered with the resin sheet <NUM> (in the case of a so-called full-laminated type), compared to those not covered with the resin sheet <NUM>, there would be a possibility that the advantageous function such as thermal insulation performance and cushioning property inherent to the foamed resin cannot be fully exhibited. Consequently, in the pallet <NUM> according to the present invention, the loading surface <NUM> is not covered with the resin sheet <NUM>, so the pallet <NUM> is of half-laminated type, and the loading surface <NUM> is an exposed surface of the foamed resin (made of foamed beads) which has thermal insulation performance and cushioning property and forms the pallet body <NUM>. Therefore, the pallet <NUM> can ensure high thermal insulation performance that makes it difficult for heat from the road surface or the warehouse floor, etc. to be transferred to the goods-conveyed placed on the pallet <NUM>, and the cushioning property unique to the foamed resin can ensure protection for the goods-conveyed against heat and shock during conveyance. Therefore, it is possible to obtain the pallet <NUM> having excellent thermal insulation performance and cushioning property with respect to the placed goods-conveyed while ensuring the strength of the outer surface of the pallet.

Further, since the pallet <NUM> is provided with exhaust holes <NUM> at the positions where the legs <NUM> are arranged on the bottom surface <NUM> of the pallet body <NUM>, after the resin sheet <NUM> is formed for covering, the exhaust holes <NUM> can be hidden. Moreover, since the exhaust holes <NUM> are provided at the peripheral edge of the fitting concave <NUM>, the decompressing effect around the flange 31a of the leg <NUM> becomes high, and the resin sheet <NUM> is more strongly stuck thereto, and the legs <NUM> and the pallet body <NUM> can be more firmly fixed. Furthermore, since the exhaust holes <NUM> do not penetrate to the top surface <NUM> of the pallet body <NUM>, any large concave is not formed on the loading surface <NUM>, and damage to the loading surface <NUM> can be suppressed.

Claim 1:
A pallet comprising:
a plate-like pallet body (<NUM>) made of foamed resin;
a plurality of legs (<NUM>) provided on a bottom surface (<NUM>) of the pallet body (<NUM>); and
a resin sheet (<NUM>) integrated by vacuum-forming from the bottom surface (<NUM>) of the pallet (<NUM>), wherein
a top surface (<NUM>) of the pallet body (<NUM>) has a loading surface (<NUM>) on which goods-conveyed are placed, and a step portion (<NUM>) formed in a shape down-step from an outer peripheral edge of the loading surface (<NUM>) to side surfaces (<NUM>) of the pallet body (<NUM>), and
the resin sheet (<NUM>) covers the bottom surface (<NUM>) of the pallet body (<NUM>), the legs (<NUM>), the side surfaces (<NUM>) of the pallet body (<NUM>) and the step portion (<NUM>), and the loading surface (<NUM>) is not covered with the resin sheet (<NUM>).