JPH09216628A - Pallet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-weighted and highly strong pallet. SOLUTION: This pallet 1 comprises a plurality of end beams 3a, 3c and a middle beam 3b distantly placed in parallel between oppositely provided deck boards 21, 22, wherein fork insertion holes 4a, 4b are formed between the end beams 3a, 3b provided at their ends and the middle beam 3b provided at the middle, while the inside of the deck boards 21, 22 are formed of grids with a plurality of ribs 6, 7 intersecting. In this case, numerous lateral ribs 7 placed in a direction crossing the longitudinal direction of the insertion hole 4 among the ribs in the deck board 21, 22 are placed with narrow intervals with respect to lateral ribs positioned at the middle beam 3c in the position of the insertion hole 4, while the lateral ribs 7 successively extend toward the end beams 3a, 3c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pallet used when an article is conveyed by a forklift or the like.

[0002]

2. Description of the Related Art Generally, when carrying a heavy article,
In order to improve the efficiency of transportation work, a plate-shaped pallet with insertion holes on the side is used. That is, the articles to be conveyed are loaded on the pallet, the fork of the forklift is inserted in the insertion hole in that state, the article is slightly lifted together with the pallet, and the forklift is moved to carry the article, Also, loading is done according to the procedure. It is desirable that this pallet has a strength to withstand the transportation of heavy articles, is lightweight, and has excellent handleability, and the demand for such a pallet is increasing.

[0003]

However, no conventional pallet has both high strength and light weight at the same time. For example, in order to reduce the weight, it is known that a girder portion is arranged between opposing deck board portions, and the deck board portion and the girder portion are formed by a grid-shaped rib. However, in order to increase the strength of the pallet, it is necessary to dispose many ribs. For this reason, the weight of the pallet increases as the number of ribs provided increases, and the strength is reduced if the number of ribs provided is reduced in order to reduce the weight of the pallet. That is, there is a contradictory relationship between the increase in strength and the reduction in weight, and it was very difficult to manufacture a pallet with high strength and light weight.

Therefore, an object of the present invention is to provide a pallet that is lightweight and has high strength.

[0005]

That is, according to the present invention, two end girders are arranged side by side between deck board parts arranged opposite to each other, and a middle girder is arranged between the end girders. As well as
In a pallet for article transportation, wherein the insides of the deck board portion, the end girder portion and the middle girder portion are formed by a lattice body in which a plurality of ribs intersect each other, the end girder portion of the ribs in the deck board portion And a plurality of horizontal ribs arranged in a direction intersecting with the insertion hole of the fork formed between the middle girder portion and the middle girder portion at a narrow interval with respect to the horizontal rib at the position of the middle girder portion at the position of the insertion hole. It is characterized in that the transverse ribs are provided and continuously extend toward the end beam portion side. Further, in the present invention, the above-mentioned lattice body is formed by intersecting vertical ribs arranged along the longitudinal direction of the insertion hole and horizontal ribs arranged along a direction orthogonal to the longitudinal direction of the insertion hole. It is characterized by being configured.

According to these inventions, ribs are not added to the entire pallet in order to increase the strength of the pallet.
By providing a large number of lateral ribs only in the necessary places, that is, in the insertion holes having a small strength and only in the vicinity of the boundaries between the insertion holes and the end girders, it is possible to increase the strength while maintaining the lightweight state. Also, since the lateral ribs extend from the insertion hole side to the end girder side, the continuity between the insertion hole side and the end girder side is enhanced, so that a load is applied on the insertion hole of the deck board part. In this case, stress concentration at the boundary between the insertion hole and the girder is avoided.

Further, the present invention is characterized in that the lateral rib extends to an intermediate position in the end girder portion. According to such an invention, an increase in weight due to the extension of the lateral rib to the end girder portion is reduced.

Further, according to the present invention, there is provided a restraining rib arranged in the end spar portion in parallel with the insertion hole and connected to an end portion of the lateral rib extending into the end spar portion. Characterize. According to such an invention, when a load is applied to the deck board, a force in the extension direction or the contraction direction acts on the lateral ribs, but at that time, the restraining ribs prevent the lateral ribs from extending or contracting. Therefore, the proof stress against a large load is improved.

Further, according to the present invention, the lateral rib extending into the end girder portion and the restraining rib arranged in the end girder portion are connected between the deck board portions facing each other. Characterize. According to such an invention, the boundary portion between the insertion hole and the end girder portion is further strengthened, and the proof stress against a large load is further improved.

Further, the present invention is characterized in that a large number of the vertical ribs at the positions of the insertion holes of the deck board portion are arranged at narrow intervals with respect to the vertical ribs at the position of the middle girder portion. According to such an invention, the reinforcing effect of the portion of the insertion hole having a small strength can be enhanced.

Further, the present invention is characterized in that the vertical ribs at positions of the insertion holes of the deck board portion are arranged at a narrow interval from the middle girder portion to the end girder portion. According to such an invention, since the reinforcing state is strengthened toward the boundary portion between the insertion hole and the girder portion where stress is likely to be concentrated, even when a load is applied to the deck board portion, the proof stress against the load is increased. Is effectively improved.

Further, the present invention is characterized in that the lateral rib at the position of the insertion hole of the deck board portion has a shape in which the thickness increases from the middle girder portion to the end girder portion. . According to such an invention, since the reinforcing state is strengthened toward the boundary portion between the insertion hole and the end girder portion where stress is likely to concentrate, even if a load is applied to the deck board portion The yield strength is effectively improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Various examples of embodiments of a pallet according to the present invention will be described below with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and the description is omitted.

(First Embodiment) FIG. 1 is a perspective view of a pallet 1. In FIG. 1, the pallet 1 is a rectangular plate body in which flat plate-shaped deck board portions 21 and 22 are arranged to face each other in the vertical direction, and an upper deck board portion 21 and a lower deck board portion are arranged. The end girders 3a and 3c and the middle girder 3b are arranged in parallel with each other in a horizontal direction while being spaced apart from each other. An insertion hole 4a is provided between the end girder portion 3a and the middle girder portion 3b.
Is formed, and an insertion hole 4b is formed between the middle girder portion 3b and the end girder portion 3c. The insertion holes 4a, 4b are holes for inserting a fork when carrying an article using the pallet 1, and are formed in the longitudinal direction of the end girders 3a, 3c and the middle girder 3b. 1 through and open at the front and back respectively. Also, the insertion holes 4a, 4
The corner of the opening of b is chamfered so that the fork can be easily inserted. In the pallet 1, the deck board portions 21, 22, the end girder portions 3a, 3c, and the middle girder portion 3b are integrally formed by a lattice body, and the upper surface plate 51, the lower surface plate 52, A front plate 53, a back plate 54, and side plates 55a and 55b are arranged. In addition, the upper plate 51, the lower plate 52, etc.,
In some cases, the arrangement may be omitted depending on the usage of the pallet 1. The lattice body intersects a plurality of vertical ribs 6 arranged along the longitudinal direction of the insertion hole 4 and a plurality of horizontal ribs 7 arranged along a direction orthogonal to the longitudinal direction, and intersects the intersecting portions. Each has a fixed structure.

As shown in FIG. 1, the vertical ribs 6 and the horizontal ribs 7 are arranged in directions orthogonal to the lower plate 52 and the upper plate 51, respectively, so as to be able to support the load from the upper plate 51 side. There is. In addition, the horizontal rib 7 is provided at the positions of the insertion holes 4a and 4b of the deck board portions 21 and 22 and the middle girder portion 3 is formed.
A large number of them are arranged at a narrower interval than the horizontal rib at the position of b.
For example, as shown in FIG. 2, the horizontal rib 7 is composed of a main rib 71 and a reinforcing rib 72, and the main rib 71 has an insertion hole 4a,
4b and the positions of the middle girder portion 3b and the end girder portions 3a and 3c are continuously arranged, and in the auxiliary rib 72, the positions of the insertion holes 4a and 4b and the end girder portions 3a and 3c. The positions up to the middle are continuously arranged. This auxiliary rib 7
By the arrangement of 2, the insertion holes 4 of the deck board portions 21, 22
The structure is such that the reinforcing state is strengthened at the position of, and the auxiliary ribs 72 of the auxiliary rib 72 extend from the insertion hole 4 side to the end girders 3a, 3a.
Since it is continuously extended to the c side, the continuity between the insertion hole 4 side and the end girders 3a, 3c side is enhanced.

Further, as shown in FIG. 2, restraining ribs 61 are arranged in parallel with the vertical ribs 6 in the end beam portions 3a and 3c. The restraining ribs 61 are arranged apart from the vertical ribs 62 serving as the side walls of the insertion holes 4a and 4b by the extension length of the auxiliary ribs 72, and are fixed to the end portions of the auxiliary ribs 72, respectively.
It has a function of transmitting the force applied to the end portion of the auxiliary rib 72 to the adjacent main rib 71.

Further, as shown in FIG. 3, the auxiliary ribs 72 and the restraining ribs 61 in the end girders 3a and 3c are connected to each other between the deck board portions 21 and 22. The face plate 52 is integrated.

Further, as shown in FIG. 2, the vertical rib 6 has a middle girder portion 3b and an end girder portion 3 at the positions of the insertion holes 4a and 4b.
A large number are arranged at narrow intervals with respect to the vertical ribs at the positions a and 3c. By arranging the vertical ribs 6 in this manner, the reinforcing state is strengthened at the positions of the insertion holes 4 of the deck board portions 21 and 22.

Next, the bending strength of the pallet 1 will be described.

As shown in FIG. 3, when articles 8 are loaded on the pallet 1, the load of the articles 8 is the deck board portion 21, the end girders 3a, 3c and the middle girder 3b on the upper surface side of the pallet 1. Is transmitted to the deck board portion 22 on the lower surface side via the. At that time, as shown in FIG. 2, the vertical ribs 6 are provided in the insertion holes 4a and 4b of the deck board portion 21 on the upper surface side.
And since many lateral ribs 7 are arranged and reinforced,
The part does not easily bend due to the load. Further, the horizontal ribs 7 in the insertion hole 4 portion of the deck board portion 21 are continuously formed toward the end girder portion 3a (3c) side not only in the main rib 71 but also in the auxiliary rib 72. The part of the insertion hole 4 and the end girder part 3a (3
Since the continuity of the portion c) is enhanced, stress concentrates near the boundary portion 21a without easily bending at the boundary portion 21a between the insertion hole 4 position and the end girder portion 3a (3c) position due to the load. There is nothing to do.

On the other hand, when the pallet 1 is bent by the load of the article 8, a contracting force or an extending force acts along the longitudinal direction of the auxiliary rib 72 as shown in FIG. That is, the contracting force acts on the auxiliary ribs 72 on the deck board portion 21 on the upper surface side of the pallet 1 along the horizontal direction, and the auxiliary ribs 72 on the deck board portion 22 on the lower surface side extends along the horizontal direction. The force will act. However, since the end portion of the auxiliary rib 72 is fixed to the restraining rib 61 on the end girder portion 3a (3c) side, contraction and extension of the auxiliary rib 72 are suppressed by the contraction force and extension force, and the load is reduced. 8 prevents the pallet 1 from being greatly curved. Thus, the load 8 applied to the deck board portion 21 is efficiently provided by the arrangement of the auxiliary ribs 72,
The pallet 1 has a large bending strength because the auxiliary rib 72 is restrained from expanding and contracting due to the load 8 while being transmitted to the 3c side and by providing the restraining rib 61.

Next, the weight reduction of the pallet 1 will be described.

The pallet 1 described above has a large bending strength and is lightweight. That is, the ribs are not added to the entire pallet to increase the strength of the pallet, but the ribs are added only to the insertion hole having a small strength and near the boundary between the insertion hole and the end girder portion, so that the pallet 1 is provided with the extra ribs. The insertion hole 4 side and the end girder 3a (3c)
Continuity with the side is given.

Specific bending strength and weight of the pallet 1 according to this embodiment will be described based on actual test data. As shown in FIGS. 2 to 5, various pallets were prepared, and bending tests and weight measurements were performed. The test and measurement were performed on the pallet 1 according to the present embodiment as shown in FIGS. 2 and 3, the pallet A as shown in FIG. 4, and the pallet B as shown in FIG. The specific dimensions of the pallet 1 are length 1100 x width 1100 x height 144.
The external shape is mm, and the insertion hole 4 having a width of 260 mm is opened. Further, the pallet B has no auxiliary ribs 72 provided in the pallet 1, and the pallet A has the auxiliary ribs 72 provided in the pallet 1 but extends toward the end girder portion 3a (3c) side. It has not been done. In the bending test, as shown in FIG. 6, a pallet is placed on parallel stands 91, 91 (width 100 mm), and steel pipes 92, 92 are placed along the positions of the insertion holes 4 on the pallet, respectively. Is placed, and a load (100 kg → 1250 line load) is gradually applied to the pallet from above through the steel pipes 92. Then, the deflection rate of the pallet was measured (JIS-Z-0602-1988). The deflection rate (%) is given by {(deflection amount at the center of the pallet) / (distance between the inner surfaces of the stands 91, 91 facing each other)} × 100.

As a result of such a bending test, data as shown in FIG. 7 was obtained. According to this data, in the pallet weight, the pallet 1 according to the present embodiment is increased by about 2% with respect to the pallet A and increased by about 9% with respect to the pallet B in accordance with the extension and extension of the auxiliary rib 72. I understand. On the other hand, in the bending rate of the bending test, the pallet 1 according to the present embodiment is improved by about 23% with respect to the pallet A as the auxiliary rib 72 is added and extended, and the pallet B is increased.
It can be seen that it is improved by about 32%. As described above, the pallet 1 is increased in amount with respect to the pallets A and B, but the bending rate in the bending test is greatly improved, and the pallet has sufficient bending strength with respect to the total weight. There is. Therefore, with the structure like the pallet 1 according to the first embodiment, it is possible to manufacture a pallet that is lightweight and has a large strength against a load.

(Embodiment 2) In the pallet 1 described above, the vertical ribs 6 at the positions of the insertion holes 4 of the deck board portions 21 and 22 extend from the middle girder portion 3b side toward the end girder portion 3a (3c) side. They may be arranged at gradually narrow intervals. For example, as shown in FIG. 8, in the pallet 1a, when the vertical ribs 6 at the positions of the insertion holes 4 in the deck board portions 21 and 22 are arranged at gradually narrow intervals, a load is applied to the pallet 1a. Insertion hole 4 where stress is easily concentrated on
The reinforcing state is strengthened toward the boundary between the position and the end girders 3a and 3c. At this time, the arrangement interval of the vertical ribs 6 may be narrowed in the arithmetic series or in the geometric series toward the end girders 3a (3c). According to the pallet 1a of the present embodiment, the same effect as that of the pallet 1 can be obtained, and the strength against a load can be effectively improved without increasing the weight of the pallet itself.

(Third Embodiment) Pallet 1 or 1 described above
In a, the main ribs 71 and the auxiliary ribs 72 at the positions of the insertion holes 4 of the deck board portions 21 and 22 gradually increase in thickness from the middle girder portion 3b side toward the end girder portion 3a (3c) side. It may be shaped. According to such a pallet, the reinforcing state is strengthened toward the boundary between the insertion hole 4 position and the end girders 3a, 3c where stress is likely to concentrate when a load is applied to the pallet. Therefore, the same effect as that of the pallet 1 can be obtained, and the strength against a load can be effectively improved.

(Fourth Embodiment) In the pallets according to the first to third embodiments described above, the auxiliary ribs 72 have end girders 3a and 3c.
May be extended to the extreme end position. Even in the pallet provided with such auxiliary ribs 72, continuity between the insertion hole 4 side of the deck board portions 21 and 22 and the end girder portions 3a and 3c side is ensured, and a large bending strength is obtained.

(Fifth Embodiment) In the first to fourth embodiments described above, the deck board portions 21 and 22, the end girder portions 3a and 3c.
Although the pallets formed by the lattice body in which the insides of the middle girders 3b are integrated are described, those pallets have the deck board parts 21, 22, the end girders 3a, 3c, and the middle girders 3b respectively. It may be formed by connecting things. That is, even if the deck board portions 21 and 22, the end girder portions 3a and 3c, and the middle girder portion 3b are separate bodies, at least the deck board portions 21 and 22 are formed of a lattice body including the vertical ribs 6 and the horizontal ribs 7. Moreover, by adopting the structure as described above, it becomes lightweight and has high strength.

[0030]

As described above, according to the present invention, the following effects can be obtained.

That is, a large number of horizontal ribs in the deck board portion are arranged at narrow intervals with respect to the horizontal ribs in the position of the middle girder portion at the position of the insertion hole, and these horizontal ribs are continuous to the end girder portion side. As a result of the extension, the effect of reinforcing the portion of the insertion hole having low strength is enhanced and the continuity between the insertion hole side and the girder portion side is enhanced. Therefore, when a load is locally applied on the insertion hole of the deck board, stress can be prevented from concentrating on the boundary between the insertion hole and the end girder, and the load can be effectively dispersed. Can be transmitted. Therefore, the deflection rate with respect to the load is reduced, and the bending strength can be improved.

Further, by adopting a structure in which the lateral rib extends to an intermediate position in the end girder portion, the weight increase due to the extension of the lateral rib to the end girder portion can be reduced, and the weight of the pallet can be reduced.

Further, since the restraining ribs fixed to the ends of the lateral ribs are provided in the end girders, the lateral ribs are prevented from expanding or contracting when a load is applied to the deck board portion, and a large load can be prevented. The yield strength can be improved.

Further, the lateral ribs extending into the end spar portion and the restraining ribs arranged in the end spar portion are connected between the deck board portions facing each other, so that the insertion hole and the end spar portion are formed. The vicinity of the boundary between and can be further strengthened, and the proof stress against a large load can be further improved.

Further, a large number of vertical ribs at the insertion hole position of the deck board portion are arranged at narrow intervals with respect to the vertical ribs at the position of the middle girder portion, so that the reinforcing effect of the insertion hole portion having small strength is obtained. Is increased.

Further, since the vertical ribs at the insertion hole position of the deck board portion are arranged at gradually narrower intervals from the middle girder portion to the end girder portion, the lateral ribs at the insertion hole position of the deck board portion are also provided. Since the ribs have a shape that increases in thickness from the middle girder to the end girder, the reinforcing state is strengthened toward the boundary between the insertion hole and the end girder where stress is likely to concentrate. Even when a load is applied to the deck board, the proof stress against that load is effectively improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a pallet according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged front view of the pallet according to the first embodiment.

FIG. 4 is an enlarged cross-sectional view of a comparative pallet in a bending test.

FIG. 5 is an enlarged cross-sectional view of a comparative pallet in a bending test.

FIG. 6 is an explanatory diagram of a bending test.

FIG. 7 is a table showing bending test data and each pallet weight.

FIG. 8 is an enlarged cross-sectional view of the pallet according to the second embodiment.

[Explanation of symbols]

1, 1a ... Pallet, 21, 22 ... Deck board part, 3
a, 3c ... end girder part, 3b ... middle girder part, 4 (4a, 4b) ...
Insertion hole, 6 ... Vertical rib, 61 ... Restraining rib, 7 ... Horizontal rib, 7
1 ... Main rib, 72 ... Auxiliary rib, 8 ... Load

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Nagaoka 1-5, Anesaki Kaigan, Ichihara, Chiba Sumitomo Chemical Co., Ltd.

Claims (8)

[Claims] 1. An end girder portion is arranged side by side between deck board portions arranged opposite to each other, a middle girder portion is disposed between the end girder portions, and the deck is also provided. In a pallet for article transportation, wherein the inside of the board portion, the end girder portion, and the middle girder portion is formed by a lattice body in which a plurality of ribs intersect, in the ribs in the deck board portion, the end girder portion and the A large number of horizontal ribs arranged in a direction intersecting the fork insertion holes formed between the middle girder portion and the horizontal ribs at the positions of the middle girder portions are arranged at narrow intervals with respect to the horizontal ribs at the positions of the insertion holes. A pallet, which is provided and whose lateral ribs extend continuously toward the end beam portion side. 2. The grid body intersects vertical ribs arranged along the longitudinal direction of the insertion hole and horizontal ribs arranged along a direction orthogonal to the longitudinal direction of the insertion hole. The pallet according to claim 1, which is configured as follows. 3. The pallet according to claim 1, wherein the horizontal rib extends to an intermediate position in the end girder portion. 4. A restraining rib is provided in the end girder portion in parallel with the insertion hole and is connected to an end portion of the lateral rib extending into the end girder portion. The pallet according to claim 1. 5. The lateral rib extending into the end girder portion and the restraining rib arranged in the end girder portion are connected between the deck board portions facing each other. The pallet according to claim 4. 6. The plurality of vertical ribs at the position of the insertion hole of the deck board portion are arranged at a narrower interval than the vertical ribs at the position of the middle girder portion. The pallet according to any one of to 5. 7. The vertical ribs at positions of the insertion holes of the deck board portion are arranged at a narrow interval from the middle girder portion to the end girder portion.
The pallet according to any one of to 6. 8. The lateral rib at the position of the insertion hole of the deck board portion has a shape in which the thickness increases from the middle girder portion toward the end girder portion. The pallet according to any one of to 7.