JP3889102B2 - Plastic pallet - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a synthetic resin pallet used for carrying, moving, storing and the like of various articles.
[0002]
[Prior art]
In a plastic pallet, the formation of reinforcing ribs that intersect vertically and horizontally on the back side of the front deck board increases the bending strength of the front deck board, so that the forklift can be used to transport and move loads. It is well known that it is extremely effective in preventing the bending of the deck board.
However, while this reinforcing rib has a great effect in increasing the bending strength of the surface side deck board, there is a problem that the weight of the synthetic resin pallet increases accordingly. Therefore, there has been considered a method of reducing the overall weight while increasing the bending strength of the front side deck board by forming hollow reinforcing ribs that are formed by crossing the back side of the front side deck board vertically and horizontally. Such a synthetic resin pallet is disclosed in JP-A-5-162751.
[0003]
[Problems to be solved by the invention]
However, as shown in FIG. 6, when the reinforcing rib 9 having the hollow portion 6 formed on the back surface of the front side deck board 1 is formed to intersect vertically and horizontally, a hollow intersecting portion 10 is formed, and this hollow intersection is formed. The bending strength was lowered at the portion 10, which caused bending.
The inventors of the present invention have reached the present invention as a result of research on a synthetic resin pallet having hollow reinforcing ribs for the purpose of further improving the bending strength of the surface side deck board.
[0004]
[Means for Solving the Problems]
The invention according to claim 1 has a front side deck board, a back side deck board, and a cylindrical girder that connects the front side deck board and the back side deck board, and a fork insertion hole is formed between the cylindrical girder. In the synthetic resin pallet, the pallet forming members in the shape of dividing the synthetic resin pallet up and down are welded and integrated to face each other , and reinforcing ribs that intersect vertically and horizontally are formed on the back surface of the front side deck board It is, and is a reinforcing rib is a solid reinforcing ribs extending along the fork insertion holes with reinforcing ribs extending in a direction perpendicular to the fork insertion holes is hollow reinforcing ribs, the tubular spar, the cylindrical A gas introducing rib having a hollow portion communicating with the hollow portion of the hollow reinforcing rib is formed along a side wall of the hollow beam, and the gas introducing rib is formed to connect the hollow reinforcing ribs. It is a synthetic resin pallet according to claim which is adapted to the hollow reinforcing rib a hollow structure by introducing a gas into the hollow reinforcing ribs through the hollow portion.
The invention according to claim 2 is the front side deck board, the back side deck board, the cylindrical girder at the corner formed at the corner connecting the front side deck board and the back side deck board, the middle of one side edge An intermediate cylindrical girder formed in the middle part, an intermediate cylindrical girder formed in the middle part of the other side edge, and a central cylindrical girder formed in the central part. In a synthetic resin pallet with a fork insertion hole formed between them, the pallet forming members having a shape obtained by dividing the synthetic resin pallet in the vertical direction are welded and integrated to face each other on the back surface of the front deck board. Reinforcing ribs that intersect vertically and horizontally are formed, and reinforcing ribs that extend in a direction orthogonal to the fork insertion holes are hollow reinforcing ribs, and reinforcing ribs that extend along the fork inserting holes are solid reinforcing ribs, The cylindrical girder is on the side of this cylindrical girder A gas introducing rib having a hollow portion communicating with the hollow portion of the hollow reinforcing rib is formed along the hollow reinforcing rib, and the gas introducing rib is formed so as to connect the hollow reinforcing ribs. The synthetic resin pallet is characterized in that the hollow reinforcing rib is formed into a hollow structure by introducing gas into the hollow reinforcing rib .
The invention according to claim 3 includes a front side deck board, a rear side deck board, a side cylindrical girder formed on both sides connecting the front side deck board and the rear side deck board, and a cylindrical girder on both sides. A synthetic resin pallet having a cylindrical girder at an intermediate portion formed in the middle and having a fork insertion hole formed between the cylindrical girders, the pallet having a shape obtained by dividing the synthetic resin pallet vertically The forming members are welded and integrated so as to face each other , reinforcing ribs that intersect in the vertical and horizontal directions are formed on the back surface of the front deck board, and the reinforcing ribs that extend in the direction perpendicular to the fork insertion holes are hollow reinforcing ribs. And a reinforcing rib extending along the fork insertion hole is a solid reinforcing rib, and a hollow portion communicating with the hollow portion of the hollow reinforcing rib along the side wall of the cylindrical girder is formed in the cylindrical girder. Gas introduction rib The gas introducing rib is formed so as to connect the hollow reinforcing ribs, and the hollow reinforcing rib is formed into a hollow structure by introducing gas into the hollow reinforcing rib through the hollow portion. It is a pallet made of synthetic resin characterized by being made.
[0005]
As such a synthetic resin pallet, it is preferable that the width of the hollow reinforcing rib is 2 mm or more larger than the width of the solid reinforcing rib.
The width of the hollow reinforcing rib is preferably 5 to 40 mm, and more preferably 8 to 30 mm.
Moreover, it is preferable that the width | variety of a solid reinforcement rib is 3-7 mm.
Further, these synthetic resin pallets may be synthetic resin pallets formed by injection-molding pallet forming members having a shape obtained by dividing the synthetic resin pallet into upper and lower parts and facing each other. preferable.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings.
In the present invention, as shown in FIGS. 1 and 2, the front deck board 1, the back deck board 2, and the cylindrical girders 3 that connect the front deck board 1 and the back deck board 2 are provided. In the synthetic resin pallet in which the fork insertion holes 4 are formed between the cylindrical girders 3, reinforcing ribs 5 that intersect vertically and horizontally are formed on the back surface of the front surface side deck board 1. In addition, as shown in FIG. 4, in each fork insertion hole 4, the reinforcing rib 5 extending in the direction perpendicular to the fork inserting direction is formed as a hollow reinforcing rib 5 a in which a hollow portion 6 is formed to be hollow. In addition, the reinforcing rib 5 extending along the fork insertion direction is a solid reinforcing rib 5b that is not hollow.
[0007]
In the flat rectangular parallelepiped synthetic resin pallet shown in FIGS. 1 and 2, the cylindrical girder 3 connecting the front side deck board 1 and the back side deck board 2 has four corners of the synthetic resin pallet. Formed at the corner of the cylindrical girder 3a at the corner, the intermediate cylindrical girder 3b formed at the middle of each pair of opposing sides, and formed at the middle of the other pair of opposing side edges The intermediate cylindrical girder 3c and the central cylindrical girder 3d formed in the central part of the synthetic resin pallet. And the fork insertion hole 4 is formed between each cylindrical girder 3a, 3b, 3c, 3d, and the reinforcing rib 5 which cross | intersected the vertical and horizontal on the back surface of the surface side deck board 1 is formed.
Further, as the reinforcing ribs 5, between the corner cylindrical girder 3a and the intermediate cylindrical girder 3b, between the corner cylindrical girder 3a and the intermediate cylindrical girder 3c, between the middle cylindrical girder 3c. Between the cylindrical girder 3b and the central cylindrical girder 3d, and between the intermediate cylindrical girder 3c and the central cylindrical girder 3d, in the interior extending in the direction perpendicular to the fork insertion hole 4 A hollow reinforcing rib 5 a having a hollow portion 6 is formed, and a solid reinforcing rib 5 b that is not hollow and extends along the fork insertion hole 4 is formed.
[0008]
Further, gas introduction ribs 8, 8,... Are formed so as to connect the hollow reinforcing ribs 5a, and a hollow portion 6 'is formed in each gas introduction rib 8 as shown in FIG. Has been. This hollow portion 6 'communicates with the hollow portion 6 of the hollow reinforcing rib 5a.
In such a synthetic resin pallet, since the hollow reinforcing rib 5a is formed, the bending strength can be increased without significantly increasing the overall weight. Moreover, since the hollow reinforcing rib is formed only in the direction orthogonal to the fork insertion hole, the hollow intersection is not formed as in the conventional example, and the bending strength is reduced or prevented from bending. Can do.
[0009]
The synthetic resin pallet according to the present invention is not limited to the illustrated example described above, and may be, for example, a synthetic resin pallet as shown in FIG. The synthetic resin pallet shown in FIG. 5 includes a front side deck board 1, a back side deck board (not shown), and side portions formed on both sides connecting the front side deck board 1 and the back side deck board. A cylindrical girder 3e and an intermediate cylindrical girder 3f formed in the middle of the cylindrical girder 3e on both sides thereof, and a fork insertion hole 4 is formed between the cylindrical girders 3e and 3f, and the surface side deck Reinforcing ribs 5 are formed on the back surface of the board 1 so as to intersect vertically and horizontally.
In the synthetic resin pallet shown in FIG. 5, the fork insertion hole 4 is provided between the side cylindrical girder 3 e and the intermediate cylindrical girder 3 f as the reinforcing rib 5 formed on the back surface of the front side deck board 1. The hollow reinforcing rib 5a which has the hollow part 6 in the inside extended in the direction orthogonal to and the solid reinforcing rib 5b extended along the fork insertion hole 4 are formed.
[0010]
In the synthetic resin pallet according to the present invention, the width of the hollow reinforcing rib 5a is preferably set to be 2 mm or more larger than the width of the solid reinforcing rib 5b. Usually, the width of the hollow reinforcing rib 5a is preferably 5 to 40 mm, more preferably 8 to 30 mm, and the width of the solid reinforcing rib 5b is preferably 3 to 7 mm.
In the synthetic resin pallet according to the present invention, the height of the hollow reinforcing rib 5a and the solid reinforcing rib 5b is preferably 20 to 40 mm from the inner surface of the front deck board 1, and the cylindrical girders 3a, 3b The wall thicknesses of 3c, 3d, 3e, and 3f are preferably 3 to 7 mm.
[0011]
The synthetic resin pallet according to the present invention can be formed, for example, by forming a pallet forming member having a shape obtained by dividing the pallet into upper and lower parts and then welding them together so as to face each other.
In order to mold the pallet forming member, the fixed mold and the movable mold are closed, the molten resin is injected into the cavity, and the molten resin is filled into the cavity. After the molten resin is cooled in the cavity while maintaining the pressure of the gas injected for a predetermined time, the fixed mold and the movable mold are opened and the pallet forming member is taken out. When the gas is injected into the molten resin gas injection portion 7, the injected gas enters a portion having a large gap in the cavity, that is, the gas introduction rib 8 into the reinforcing rib 5a and the like, and has a hollow portion 6 inside. The reinforcing rib 5a and the gas introducing rib 8 having the hollow portion 6 'inside are formed. However, since the injected gas does not enter the reinforcing rib 5b having a small gap before it, the solid reinforcing rib 5b is formed. Usually, the gas introduction rib 8 preferably has a width and height of about 10 mm.
[0012]
Since the internal pressure of the gas that has entered the hollow reinforcing rib 5a acts evenly on the inner wall of the mold part, the thickness of the molded hollow reinforcing rib 5a is almost constant and the thickness is not extremely unevenly distributed. Dimensional variation during molding can be reduced. Furthermore, by forming the hollow portion 6 in the hollow reinforcing rib 5a as described above, effects such as weight reduction of the synthetic resin pallet and shortening of the molding time can be obtained.
The amount of gas injected into the hollow reinforcing rib 5a and the like at the time of injection molding of the pallet forming member is adjusted by the required strength of the synthetic resin pallet. Usually, it is preferable to inject the gas so that the apparent density of the entire synthetic resin pallet is about 0.75 to 0.95 times the density of the raw synthetic resin.
[0013]
The injection molding conditions for the pallet forming member may be normal conditions. For example, when high-density polyethylene is used as the material, conditions of a melting temperature (cylinder temperature) of 200 to 250 ° C. and an injection rate of about 2000 to 5000 cc / sec are preferable. . The synthetic resin constituting the pallet is generally a polyolefin such as polyethylene, polypropylene, or ethylene-propylene copolymer, but it goes without saying that other synthetic resins may be used in some cases.
Furthermore, it goes without saying that additives such as colorants and fillers may be used as appropriate. Further, these synthetic resins may be mixed with a commonly used organic or inorganic foaming agent to form a foam. In this case, the expansion ratio is preferably about 1.05 to 1.4. In this case, the apparent density of the entire pallet is preferably about 0.65 to 0.9 of the density of the raw material synthetic resin.
[0014]
The synthetic resin pallet according to the present invention usually has the same structure as the pallet forming member on the back surface side and the pallet forming member on the front surface side. It is good also as a structure different from a member.
The synthetic resin pallet according to the present invention usually forms reinforcing ribs that intersect vertically and horizontally not only on the back surface of the front deck board 1 but also on the back surface of the back deck board 2 and is orthogonal to the fork insertion holes. The reinforcing ribs extending in the right direction may be used as the hollow reinforcing ribs and the reinforcing ribs extending along the fork insertion holes may be used as the solid reinforcing ribs. Ribs may be formed, and solid reinforcing ribs that intersect vertically and horizontally may be formed on the back surface of the back deck board 2.
[0015]
【The invention's effect】
In the synthetic resin pallet according to the present invention, reinforcing ribs that intersect vertically and horizontally are formed on the back surface of the front deck board, and the reinforcing ribs extending in the direction orthogonal to the fork insertion holes are hollow ribs. By doing, strength can be improved while suppressing an increase in weight. At this time, by setting the reinforcing rib intersecting with the hollow reinforcing rib to be a non-hollow rib, the intersecting portion does not become hollow, a decrease in bending strength can be prevented, and bending can be prevented.
[Brief description of the drawings]
FIG. 1 is a side view showing an example of a synthetic resin pallet according to the present invention.
FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 and is a partial view of a quarter of the synthetic resin pallet;
3 is a cross-sectional view taken along the line BB in FIG.
4 is a cross-sectional view taken along the line CC of FIG.
FIG. 5 is a partial cross-sectional view similar to FIG. 2, showing another example of the synthetic resin pallet of the present invention.
FIG. 6 is a partial cross-sectional view of a conventional synthetic resin pallet.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Front side deck board 2 Back side deck board 3 Cylindrical girder 3a Cylindrical girder 3b, 3c Cylindrical girder 3d Central cylindrical girder 3e Side cylindrical girder 3f Middle cylindrical Girder 4 Fork insertion hole 5 Reinforcement rib 5a Hollow reinforcement rib 5b Solid reinforcement rib

Claims (8)

In a synthetic resin pallet having a front side deck board, a back side deck board, and a cylindrical girder that connects the front side deck board and the back side deck board, and a fork insertion hole is formed between the cylindrical girder. ,
The pallet forming members of the shape obtained by dividing the synthetic resin pallet into upper and lower parts are oppositely welded and integrated,
Reinforcing ribs that intersect vertically and horizontally are formed on the back surface of the front deck board, and the reinforcing ribs extending in the direction perpendicular to the fork insertion holes are hollow reinforcing ribs, and the reinforcing ribs extending along the fork insertion holes are It is a solid reinforcing rib,
A gas introducing rib having a hollow portion communicating with the hollow portion of the hollow reinforcing rib is formed on the tubular girder along the side wall of the tubular girder.
The gas introducing rib is formed so as to connect the hollow reinforcing ribs, and the hollow reinforcing rib is formed into a hollow structure by introducing gas into the hollow reinforcing rib through the hollow portion. A synthetic resin pallet characterized by The front side deck board, the back side deck board, the cylindrical girder at the corner connecting the front side deck board and the back side deck board, the intermediate part formed at the middle part of one side edge It has a cylindrical girder, an intermediate cylindrical girder formed in the middle part of the other side edge, and a central cylindrical girder formed in the central part, and a fork insertion hole is formed between the cylindrical girder In the synthetic resin pallet
The pallet forming members of the shape obtained by dividing the synthetic resin pallet into upper and lower parts are oppositely welded and integrated,
Reinforcing ribs that intersect vertically and horizontally are formed on the back surface of the front deck board, and the reinforcing ribs extending in the direction perpendicular to the fork insertion holes are hollow reinforcing ribs, and the reinforcing ribs extending along the fork insertion holes are It is a solid reinforcing rib,
A gas introducing rib having a hollow portion communicating with the hollow portion of the hollow reinforcing rib is formed on the tubular girder along the side wall of the tubular girder.
The gas introducing rib is formed so as to connect the hollow reinforcing ribs, and the hollow reinforcing rib is formed into a hollow structure by introducing gas into the hollow reinforcing rib through the hollow portion. A synthetic resin pallet characterized by Front side deck board, back side deck board, side cylindrical board formed on both sides connecting the front side deck board and back side deck board, and intermediate part formed in the middle of both side cylindrical girders In a synthetic resin pallet having a cylindrical girder with a fork insertion hole formed between the cylindrical girder,
The pallet forming members of the shape obtained by dividing the synthetic resin pallet into upper and lower parts are oppositely welded and integrated,
Reinforcing ribs that intersect vertically and horizontally are formed on the back surface of the front deck board, and the reinforcing ribs extending in the direction perpendicular to the fork insertion holes are hollow reinforcing ribs, and the reinforcing ribs extending along the fork insertion holes are It is a solid reinforcing rib,
A gas introducing rib having a hollow portion communicating with the hollow portion of the hollow reinforcing rib is formed on the tubular girder along the side wall of the tubular girder.
The gas introducing rib is formed so as to connect the hollow reinforcing ribs, and the hollow reinforcing rib is formed into a hollow structure by introducing gas into the hollow reinforcing rib through the hollow portion. A synthetic resin pallet characterized by The synthetic resin pallet according to any one of claims 1 to 3, wherein the hollow reinforcing rib has a substantially rectangular cross section.   The synthetic resin pallet according to any one of claims 1 to 4, wherein a width of the hollow reinforcing rib is 2 mm or more larger than a width of the solid reinforcing rib.   The width | variety of a hollow reinforcement rib is 5-40 mm, The synthetic resin pallet of any one of Claims 1-5.   The width | variety of a hollow reinforcement rib is 8-30 mm, The synthetic resin pallet of any one of Claims 1-5.   The width | variety of a solid reinforcement rib is 3-7 mm, The synthetic resin pallet of any one of Claims 1-7.

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