JPH0423631B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pallet made of a synthetic resin foam molding used as a platform when transporting cargo by a forklift or the like, and a method for manufacturing the pallet.

(Prior art) Traditionally, pallets have often been made of wood or metal, but in recent years, pallets made of synthetic resin injection molded bodies and pallets (for example, Japanese Patent Application Laid-Open No. 153622/1983) have been used.
Pallets made of extruded synthetic resin foam also came into use.

Also, Japanese Utility Model Publication No. 143322/1983, Japanese Patent Application Publication No. 1983-
In Publication No. 171342 and Japanese Patent Application Laid-open No. 171343,
A pallet made of in-mold foam molded polyolefin resin foam particles obtained by fitting a pallet component of an upper plate and a pallet component of a lower plate is disclosed.

(Problems to be Solved by the Invention) Pallets are required to have sufficient strength. For this reason, wooden pallets and metal pallets use thick frame materials and thick board materials, and the pallets themselves are quite heavy.For this reason, wooden pallets and metal pallets have poor workability and are unsafe. It also had some flaws. Additionally, wooden pallets were prone to hangnails and cracks, causing damage to cargo and injury to workers. Furthermore, since wooden pallets have water absorbing properties, they are susceptible to the growth of mold, bacteria, and other bacteria, which has been a particular problem in the food and pharmaceutical industries.

Pallets made of synthetic resin injection moldings are often non-foamed, hard, and have poor cushioning power, so they have the disadvantage that small impacts can damage cargo. Pallets made of extruded synthetic resin foam have a directional "stress" characteristic of extruded products, which has the disadvantage of causing the pallet to warp.

Also, Japanese Utility Model Publication No. 143322/1983, Japanese Patent Application Publication No. 1983-
The pallets disclosed in Publication No. 171342 and Japanese Patent Application Laid-Open No. 17134/1983 require that each pallet component be molded to have the same area as the pallet, and the area of the pallet component is large, requiring the use of a large in-mold molding machine. Without it, production would be impossible and uneconomical. In addition, when trying to improve the lightweight and cushioning properties of synthetic resin foam pallets, there is a problem that the strength decreases, and furthermore, the area around the fork finger insertion part is easily damaged by the fork fingers. It was hot too.

The object of the present invention is to provide a pallet that overcomes the drawbacks of the conventional products mentioned above. That is,
The present invention is made of a synthetic resin foam molding that has sufficient strength, is lightweight, has excellent cushioning power, does not absorb water, does not warp, is easy to work with, and has excellent safety. The purpose is also to provide a palette.

Another object of the present invention is to provide a method for manufacturing pallets of synthetic resin foam moldings that can be sufficiently manufactured using a small-sized in-mold molding machine.

(Means for Solving the Problems) As a result of intensive research in view of the above points, the present inventors have determined that the ends of a plurality of pallet constituent members made of in-mold foam molded articles of synthetic resin pre-expanded particles are connected to each other. The present invention has been completed by successfully developing a lightweight and strong synthetic resin foam molded pallet, which is formed by joining the pallet components in the width direction to integrate them, and a method for manufacturing the same.

That is, the synthetic resin foam molded pallet of the present invention is made of an in-mold foam molded product of pre-expanded synthetic resin particles, has a density of 0.0045 to 0.3 g/cm ³ , and a compressive strength at 25% compression of 2.0 Kg/cm ² or more. The end portions of two or more pallet constituent members are joined together in the width direction of the pallet to integrate them, and at least the opening edge side of the fork finger insertion portion is covered with a protective cover. . In addition, the method for producing pallets made of synthetic resin foam moldings of the present invention has a density of 0.03 to
0.45 g/cm ³ of pre-expanded synthetic resin particles are filled into a mold, heated and foamed to form a pallet component in the shape of dividing the pallet into two or more parts.
The ends of the above pallet constituent members are joined together in the width direction of the pallet, the pallet constituent members are integrated with each other and formed into a desired shape and size, and then,
The pallet is characterized in that a protective cover is attached to at least the opening edge side of the fork finger insertion part to obtain the pallet.

Example Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2, FIG. 4, FIG. 6, and FIG. 8 are perspective views showing one embodiment of the pallet of the present invention (all of them show the state before the protective cover is attached). Each,
1 and 1' are pallet constituent members, 2 is a fork finger insertion part for inserting the fork finger of a forklift, and 3 is a joint part. It is formed so as to pass through to the other side facing the other side. The pallet constituent members 1 and 1' are formed from in-mold foam moldings of pre-expanded synthetic resin particles, and the foam moldings have a density of 0.045 to 0.3 g/cm ³ , particularly a density of
Those having a compressive strength of 0.05 to 0.18 g/cm ³ and a compressive strength of 2.0 Kg/cm ³ or more at 25% compression are preferable because they have sufficient strength, are lightweight, and have excellent buffering force. If the density is less than 0.045g/ ^cm3 , the strength is likely to be insufficient,
If the density exceeds 0.3 g/cm ³ , the weight may be too heavy and workability may be reduced. Also, those whose compressive strength at 25% compression is less than 2.0 Kg/cm ³ are likely to have insufficient strength.

1 is a perspective view showing the component 1 of the pallet in FIG. 2, FIG. 3 is a perspective view showing the component 1 at the end of the pallet in FIG. 4, and FIG. 5 is a perspective view of the end of the pallet in FIG. 6. FIG. 7 is a perspective view showing the component 1 of the section.
FIG. 2 is a perspective view of the component 1 at the end of the pallet shown; Figures 9 and 10 are Figures 2 and 4, respectively.
FIG. 3 is a partial cross-sectional view showing the joint portion of the pallet shown in the figure. The pallet of the present invention uses pallet component members 1 and 1' divided into two or more parts, whose ends are joined in the width direction of the pallet. Joining in the "width direction of the pallet" means joining in the direction along the formation direction of the fork finger insertion part 2 as shown in Figures 2 and 4, as well as joining in the direction along the formation direction of the fork finger insertion part 2 as shown in Figure 6. This also includes a case where the connection is made in a direction perpendicular to the direction in which the insertion portion 2 is formed. Further, as shown in FIG. 8, it also includes a case where the fork finger insertion portion 2 is joined in both directions along the direction in which it is formed and in a direction perpendicular to it. "Joining" refers to the case where the ends of the pallet components are bonded together using heat fusion or adhesive (for example, when the joint surfaces of the pallet components are flat as shown in Figure 9), they are bonded together as shown in Figure 10. They may be fitted by engaging a concave part and a convex part, or by engaging a wedge-shaped concave part and a convex part (not shown) (Fig. 10). In cases where a concave part and a convex part are engaged with each other, or a wedge-shaped concave part and a convex part are engaged with each other, they are not only simply fitted, but also heat-fused or bonded with adhesive. ).

The palette of the present invention is shown in FIGS. 2, 4 and 6.
It may be a two-way pallet having two fork finger insertion portions 2 as shown in the figure, or a four-way pallet with a pair of fork finger insertion portions 2 intersecting each other at right angles as shown in FIG. It may also be a four-sided pallet having a slot 2. Further, the pallet of the present invention may be provided with three or more insertion portions in accordance with a special forklift having three or more fork fingers.

The palette of the present invention is shown in FIGS. 2, 6 and 8.
It may be a double-sided pallet, as shown in the figure, or a single-sided pallet, as shown in FIG.

The pallet of the present invention may have various shapes other than those described above depending on the purpose. For example, in order to prevent the cargo from slipping off the pallet, projections may be provided at the corners of the pallet surface, or irregularities may be formed on the pallet surface to increase the degree of slippage.

Pallet constituent members in the present invention include polyethylene (low-density polyethylene, linear low-density polyethylene, high-density polyethylene, etc.), polypropylene, ethylene-propylene random copolymer, ethylene-propylene block copolymer, ethylene-styrene copolymer. , olefin resins such as ethylene-vinyl acetate copolymers, styrene resins such as polystyrene, styrene-butadiene copolymers, styrene-maleic anhydride copolymers, and pre-expanded particles of synthetic resins such as vinyl chloride resins. It consists of an in-mold foamed product, and the pre-expanded particles of synthetic resin may be crosslinked or non-crosslinked. Among these, those obtained by in-mold foam-molding of pre-expanded particles of olefinic resin are the most preferred, as they have sufficient toughness and flexibility, have excellent impact resistance, and have high buffering power.

Furthermore, if a weather-resistant material such as carbon black, an antioxidant, an ultraviolet absorber, etc. are mixed into the in-mold foam molded product of the pre-expanded synthetic resin particles forming the pallet of the present invention, a pallet with excellent weather resistance can be obtained. It's preferable.

The strength of the pallet of the present invention may be increased by using reinforcing tools or the like. For example, FIG. 11 is a longitudinal sectional view taken along the line XI-XI in FIG. 4, and FIG. 12 is a longitudinal sectional view taken along the line XII-XII in FIG. ing. A screw groove for fastening is formed in the reinforcing tool 5, and the fastening tool 6 is screwed into the reinforcing tool 5 to fasten the reinforcing tool 5. In the pallet component, for example, the insertion hole 4 for the reinforcing tool 5 may be formed in advance as in the component 1 shown in FIGS. A through hole for inserting the reinforcing device 5 may be formed later.
Not only when inserting in the direction crossing the joint 3 as shown in FIG. 2, FIG. 4, and FIG. 6, but also when inserting in the direction crossing the joint 3 as shown in FIG. Alternatively, as in the embodiment shown in FIG. 13, it may be inserted in a direction intersecting the joint 3 and at the position of the joint 3 along the joint 3. Also,
As in the embodiment shown in FIG. 14, it may be inserted in a manner that intersects the joint portion 3, and may also be inserted in the vicinity of the joint portion 3 in parallel with the approach portion 3. Alternatively, the reinforcing device 5 may be inserted only in the direction intersecting the joint 3, only at the position of the joint 3, or only in the direction parallel to the joint 3 near the joint 3. In particular, it is preferable to insert the reinforcing tool 5 in a direction that intersects the joint portion 3 because the reinforcing effect on the pallet will be greater. Reinforcer to be inserted 5
The number of is 7 in Figure 13, and in Figure 14
There are 11 pieces, but you can choose as appropriate.

The shape of the reinforcing device 5 may be pipe-like or rod-like.
The reinforcing member 5 may be made of metal such as iron or aluminum, reinforced plastic (FRP), or the like, as appropriate.

FIG. 15 shows the pallet in a completed state, with a protective cover attached to the opening edge side of the fork finger insertion part 2. As shown in FIG. 16, the protective cover 7 covers the end edges 8 on both the left and right sides of the pallet to prevent the pallet from being damaged, and at the same time protects the opening 2' of the fork finger insertion part 2 and the opening 2' of the fork finger insertion part 2. A part of the fork finger insertion part 2 near the part 2' is also covered to prevent the pallet from being damaged by the fork finger during work. The protective cover 7 also has the effect of increasing the strength of the entire pallet.
The protective cover is not limited to the shape shown in FIG. 15. Although not shown, it is also possible to combine two protective covers with a roughly L-shaped cross section to cover the four circumferences of the pallet. (A protective cover without an insertion opening may be used on the side wall of the fork finger insertion part 2 that does not have an opening 2'.)

The inner wall 9 of the fork finger insertion part 2 is the 16th
It is preferable to protect with a protective material 10 as shown in the figure. The shape of the protective material 10 can be selected as appropriate, and it is particularly preferable that the protective material 10 has an elongated hollow shape with a rectangular cross section that can cover substantially the entire surface of the upper, lower, left, and right inner walls 9 of the fork finger insertion portion 2. It may be one that partially covers the upper, lower, left and right inner walls 9. In addition, a protective material may be provided partially at key points that are particularly susceptible to damage due to contact with the fork finger during transportation, such as the ceiling of the inner wall of the fork finger insertion part 2. In this case, the protective material may be in the form of a strip, for example. It can be an object, a pipe or a stick. In the case of pipes or rods, it is preferable to provide two of them as a pair on the ceiling of the fork finger insertion part 2, and the interval between these two pipes or rods to be slightly narrower than the width of the fork finger.

FIG. 17 is an enlarged explanatory view of the engagement portion between the protective cover 7 and the protective material 10 in FIG. 16. By locking and connecting the protective cover 7 and the protective material 10 with each other in this manner, both the protective cover 7 and the protective material 10 are reliably attached to the pallet, which is preferable.

FIG. 18 is a perspective view of a main part showing still another embodiment of the pallet of the present invention. This palette is number 20
As shown in the figure, an edge protection cover 11a and a receptacle protection cover 11b cover the edge 8 of the pallet.
The opening 2' of the fork finger insertion portion 2 and its surrounding area are covered with an insertion port protection cover 11b. In this case, it is preferable that the insertion port protection cover 11b and the protection member 10 are connected by the same interlocking structure as shown in FIG. 17.

Further, as shown in FIG. 19 (FIG. 19 shows the state before the protective cover 7 is attached), a reinforcing member 10' having a hollow shape with a square cross section is used to strengthen the inner wall 9 of the fork finger insertion part 2. Of these, only the periphery of the portion corresponding to the joint portion 3 and/or the tip of the fork finger may be covered.

The above-mentioned reinforcing members 10, 10' may be made of metal such as iron or aluminum, reinforced plastic (FRP), or the like, as appropriate.

The above-mentioned protective cover 7 and edge protection cover 11
a. The insertion port protective cover 11b is an injection molded product made of acrylonitrile-butadiene-styrene copolymer, styrene-butadiene copolymer, high-density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, etc., iron or aluminum. A molded product made of a thin metal plate, etc., is used as appropriate.

The method for producing pallets of the present invention includes first filling pre-expanded particles into a mold that can be closed but not sealed;
By heating and foaming, a pallet component (in-mold foam molded product) in the shape of a pallet divided into two or more is obtained. The pre-expanded particles used at this time have a density of 0.03 to 0.45.
g/cm ³ is preferred. The density of the pre-expanded particles here refers to the bulk density, and the pre-expanded particles are approximately
It is the value obtained by dividing the weight of particles when filled into a 200c.c. container by the volume of the container. When it is desired to obtain a weather-resistant pallet, weather-resistant materials such as carbon black, antioxidants, ultraviolet absorbers, etc. may be mixed in advance with the pre-expanded particles. The agent is filled with pre-expanded particles into a mold that can be closed but cannot be sealed, heated,
It may also be foamed. The above-mentioned mold has an inner surface shape that corresponds to the shape of the final pallet that is divided into two or more parts, and small holes are formed on the mold surface through which a heating medium such as water vapor passes. You can use whatever you have.

Next, the end portions of the pallet constituent members each having a shape of two or more divisions are joined together in the width direction of the pallet to integrate the pallet constituent members. Prior to joining, it is preferable that the dimensions of each pallet component be made uniform by cutting or the like. As mentioned above, the joining means include, for example, heat fusing using an appropriate heating means, adhesion using an adhesive, and interlocking of concave and convex parts formed at each end of the pallet components to be joined. Examples include means for matching.

When thermal fusion is performed, by forming the pallet constituent members in advance to be slightly larger than a predetermined size, the dimensions can be accurately adjusted depending on the degree of fusion during fusion. Examples of the heating means used during heat fusion include a heating plate, heating blade, hot air, and the like.

When bonding using adhesive, the dimensions can be adjusted by cutting the ends of the pallet components to be joined to an arbitrary width, or conversely, inserting an intervening member of an arbitrary width between both ends. However, it may be adapted to the desired dimensions. For example, adhesives containing acrylic resin, vinyl acetate resin, olefin resin, ethylene-vinyl acetate copolymer, acrylonitrile-butadiene copolymer, polyvinyl alcohol, styrene-butadiene copolymer, etc. are used. Ru.

When joining, pallets with various widths and lengths can be manufactured by appropriately combining and joining the pallet constituent members.

After joining the ends of the plurality of pallet constituent members in the width direction of the pallet as described above, the protective cover 7, edge protection cover 11a, insertion port protection cover 11b, etc. are attached, and further reinforcement is applied as necessary. By appropriately attaching the tools 6 and the like, a pallet made of a synthetic resin foam molding is obtained.

(Effects of the Invention) The synthetic resin foam molded pallet of the present invention has sufficient strength because it is formed by bonding two or more pallet constituent members with specific density and compressive strength.
It is lightweight and has excellent cushioning power. Furthermore, since the pallets of the present invention are made of in-mold foam moldings of pre-expanded synthetic resin particles, there is no "stress" in a specific direction, there is no risk of warping, there is no deformation due to distortion, and the pallets do not have the same shape as wooden pallets. There is no risk of hangnails or cracks, so workability is good and safety is excellent. Furthermore, since its water absorption is extremely low,
There is no possibility that bacteria such as mold or bacteria will develop. Moreover, since at least the opening edge side of the fork finger insertion portion is covered with the protective cover, there is no risk of the pallet being damaged by the fork finger, and the strength of the entire pallet can be further improved.

Furthermore, according to the method for producing pallets made of synthetic resin foam moldings of the present invention, pallets of various sizes can be produced by appropriately combining pallet constituent members in the shape of dividing a pallet into two or more parts and joining them in the width direction of the pallet. Even when manufacturing pallets of different sizes, there is no need to prepare molds of a size corresponding to each pallet size, and the molds for molding the pallet components used in the present invention are small. Since it can be used as a mold, the cost of molding molds can be significantly reduced, and pallets of various sizes with excellent physical properties can be manufactured at low cost.

[Brief explanation of drawings]

1, 3, 5, and 7 are perspective views showing different embodiments of pallet constituent members constituting the pallet of the present invention, and FIG. 2, FIG. 4, and FIG. 6, respectively.
Figures 8, 13, and 14 are perspective views showing different embodiments of the pallet before the protective cover is attached, and Figure 15 is the protective cover attached to the opening edge side of the fork finger insertion part. A perspective view showing the state, FIG. 9 is a vertical sectional view of the main part taken along the - line in FIG. 2, FIG. 10 is a longitudinal sectional view of the main part taken along the - line in FIG. -XI line longitudinal cross-sectional view, 1st
2 is a longitudinal sectional view taken along the line XII--XII in FIG. 1, FIG. 16 is a plan sectional view taken along the - line in FIG. FIG. 19 is a plan sectional view showing still another embodiment of the pallet before the protective cover is attached, and FIG. 20 is a perspective view of the main part of another embodiment of the pallet.
FIG. 3 is a vertical cross-sectional view of the main part taken along line XX. 1, 1'...Pallet constituent members, 3...Joint portion.

Claims (1)

[Scope of Claims] 1. Two or more pallets made of in-mold foamed products of pre-expanded synthetic resin particles, having a density of 0.045 to 0.3 g/cm ³ and a compressive strength at 25% compression of 2.0 Kg/cm ³ or more. Synthetic resin foam molding, characterized in that the ends of the constituent members are joined together in the width direction of the pallet and are integrated, and at least the opening edge side of the fork finger insertion part is covered with a protective cover. Body palette. 2. Pre-expanded synthetic resin particles with a density of 0.03 to 0.45 g/cm ³ are filled into a mold, heated and foamed to form pallet constituent members in the shape of dividing the pallet into two or more parts, and then two or more pallet constituent members are formed. The ends of the pallet are joined in the width direction of the pallet, the pallet constituent members are integrated with each other and formed into a desired shape and size, and then a protective cover is attached at least to the opening edge side of the fork finger insertion part. A method for producing a pallet made of a synthetic resin foam molding, characterized in that: