JP3934716B2 - Plastic pallet - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a synthetic resin pallet, and more particularly, to a forklift pallet used for carrying, moving, and storing articles.
[0002]
[Prior art]
Conventionally, as a pallet for a forklift, a product made of a synthetic resin is manufactured and used. Usually, this type of synthetic resin pallet is basically formed by forming a pallet forming member having a shape obtained by dividing the pallet into upper and lower parts by injection molding and integrating these two pallet forming members.
[0003]
That is, the pallet forming member formed by injection molding intersects the deck board that forms the loading surface, the girders (legs) provided at appropriate positions on the inner surface of the deck board, and the inner surface of the deck board vertically and horizontally. The reinforcing ribs are provided, the pallet forming members are opposed to each other, the beams are butted, and the butted portions are welded and integrated.
[0004]
Forming such reinforcing ribs on the inner surface of each pallet forming member increases the bending strength of the deck board, and prevents the deck board from bending when carrying and moving the load with a forklift. It is well known that it is extremely effective.
[0005]
However, such a reinforcing rib has a great effect in increasing the bending strength of the deck board as described above, but there is a problem that the weight of the synthetic resin pallet increases accordingly. Therefore, a method of reducing the overall weight while increasing the bending strength of the deck board by forming the reinforcing rib hollow was considered. Such a synthetic resin pallet is disclosed in JP-A-5-162751.
[0006]
[Problems to be solved by the invention]
By the way, the above-described conventional synthetic resin pallet has a very high evaluation because the bending strength of the deck board is very large due to the hollow reinforcing rib, but is lighter than the conventional product in terms of weight.
[0007]
However, the hollow reinforcing ribs are strong in bending strength but not so strong in impact strength. Therefore, the reinforcing ribs in the fork insertion port of the synthetic resin pallet accidentally collide with the fork when the fork is inserted. Then, it was easily broken by impact, and there was a problem from the viewpoint of durability of the synthetic resin pallet.
[0008]
In addition to the above-mentioned problems, the conventional synthetic resin pallet is adjacent to the fork insertion port, in other words, the ends of the spar on both sides of the fork insertion port are also easily damaged by collision with the fork. Even if the strength of the pallet is increased, the durability of the entire pallet cannot be improved if the ends of the girders on both sides are damaged.
[0009]
An object of the present invention is to solve such a conventional problem, and is provided with a reinforcing rib of a fork insertion port and a girder end adjacent to the fork insertion port while having a light weight and a large bending strength. It is to provide a highly durable synthetic resin pallet that protects against fork damage.
[0010]
[Means for Solving the Problems]
The present invention is a synthetic resin pallet, which is configured as follows in order to achieve the technical problem described above. That is, the present invention is a synthetic resin pallet formed by injection-molding a pallet forming member having a shape obtained by dividing a pallet into upper and lower parts, and these are opposed to each other, the pallet forming member being loaded A deck board for forming a surface, a thin girder provided on the deck board, and reinforcing ribs provided vertically and horizontally on the inner surface of the deck board, wherein the reinforcing rib is a fork insertion of the synthetic resin pallet. A solid rib formed on the edge of the deck board along the mouth, and a hollow rib formed on the inner surface of the deck board other than the edge, and an end portion where the girder is adjacent to the fork insertion port It is characterized by being provided with a relatively small sealed hollow portion that divides the internal space of the girder.
[0011]
<Specific Configuration in the Present Invention>
The synthetic resin pallet of the present invention is composed of the above-described essential components, but it is established even when the components are specifically as follows. The specific component is a first wall in which a partition wall forming the sealed hollow portion in the end portion of the beam is formed between the side walls of the beam along the fork insertion direction inserted from the fork insertion port. It is composed of a partition part and at least one second partition part parallel to the fork insertion direction so as to further divide the space part defined by the first partition part and the side wall of the beam. is there.
[0012]
Further, in the synthetic resin pallet of the present invention, the partition wall forming the sealed hollow portion in the end portion of the beam is formed between the side walls of the beam along the fork insertion direction inserted from the fork insertion port. At least one second partition formed at an angle α with respect to the fork insertion direction to further divide the first partition portion and the space defined by the first partition portion and the side wall of the beam. The angle α is set within a range of 0 ° <α <90 °.
[0013]
Further, the solid rib formed on the edge of the deck board along the fork insertion port of the synthetic resin pallet, which is an important component constituting the present invention, is provided along the solid rib. It is preferable to connect the adjacent hollow ribs with a plurality of solid connecting ribs arranged at predetermined intervals.
[0014]
In the synthetic resin pallet of the present invention, the thickness of the girders is about 3 mm to 7 mm, the width of the hollow rib is about 8 mm to 40 mm, and the width of the solid rib is larger than the width of the hollow rib. It is particularly preferable to reduce the thickness in terms of reducing the weight, maintaining a predetermined bending strength, and improving the impact strength around the fork insertion port.
[0015]
According to the synthetic resin pallet of the present invention, as a whole, a pallet forming member having a shape obtained by dividing the pallet into upper and lower parts is formed by injection molding, and these are formed so as to be opposed to each other and welded together. When each pallet forming member is formed by injection molding, the inside of the reinforcing rib provided vertically and horizontally on the inner surface of the deck board is made hollow by injecting gas into the reinforcing rib from a predetermined position before solidifying.
[0016]
However, the reinforcing rib formed on the deck board edge along the fork insertion port in this synthetic resin pallet is designed to have a small width, so that the reinforcing rib having a relatively large width formed at an adjacent position is used. The gas injected into the edge hardly enters the reinforcing rib formed at the edge, and as a result, the reinforcing rib formed at the edge is solid.
[0017]
Solid reinforcing ribs have high impact strength, so when a fork is inserted into a fork insertion slot, it will not easily be damaged even if it accidentally collides with the reinforcing rib formed along the edge, so synthetic resin The durability of the pallet made can be improved. Moreover, the solid reinforcing ribs are only the reinforcing ribs formed on the deck board edge along the fork insertion port and the connecting ribs connecting the reinforcing ribs and the hollow reinforcing ribs formed along the reinforcing ribs. Therefore, it does not hinder the weight reduction.
[0018]
Furthermore, in this synthetic resin pallet, since a relatively small sealed hollow portion is formed so as to divide the internal space of the spar in the end portions of the spar located on both sides of the fork insertion port, the strength of the end portion is increased. It is possible to prevent fatal damage to the girder even if it is accidentally collided with the end of the girder when the fork is inserted into the insertion slot.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the synthetic resin pallet of the present invention will be described in more detail with respect to an embodiment shown in the drawings. FIG. 1 shows a further one-fourth portion of a lower half pallet forming member 10 having a shape obtained by dividing a synthetic resin pallet according to an embodiment of the present invention into upper and lower halves. The pallet forming member 10 includes a deck board 11, girders or legs 12 formed at both end portions and an intermediate portion inside the deck board 11, and reinforcing ribs 13 which are also provided so as to intersect vertically and horizontally inside the deck board 11. And is configured.
[0020]
The synthetic resin pallet according to this embodiment is formed by abutting the spar 12 with the pallet forming members 10 facing each other, and welding and integrating the butted portions. This girder 12 presents a cylindrical body and is preferably formed with a thin wall of about 3 to 7 mm. When the synthetic resin pallet is viewed from the side, the space (hole) between the beam 12 and the beam 12 becomes the fork insertion hole 14.
[0021]
The reinforcing ribs 13 that are provided inside the deck board 11 so as to intersect vertically and horizontally are composed of two types of solid ribs 13a and hollow ribs 13b. The former solid rib 13 a is formed at the edge of the deck board along the entrance of the fork insertion hole 14, that is, the fork insertion opening 15. The reinforcing ribs 13 formed on the inner surface of the deck board other than the solid ribs 13a (excluding the inside of the girders 12) are all hollow ribs 13b.
[0022]
However, the solid ribs 13a formed at the edge along the fork insertion port 15 are connected to the hollow ribs 13b formed in parallel and adjacent to the ribs 13c with a plurality of connecting ribs 13c spaced apart from each other. However, the connecting rib 13c is also solid. Thus, by connecting the solid rib 13a to the adjacent hollow rib 13b with a plurality of connecting ribs 13c, the impact strength against the solid rib 13a can be further increased.
[0023]
Now, one method of using the reinforcing rib 13 formed inside the deck board 11 as a hollow rib is as follows. That is, as shown in FIG. 2, the mold is formed in advance so that the width dimension L of the reinforcing rib as a hollow rib is about 8 to 40 mm and the height H from the inner surface of the deck board 11 is about 20 to 40 mm. The predetermined part of is designed. The mold has a plurality of gas injection holes (on the surface of the deck board 11 of the molded pallet forming member 10 in FIG. 1) so as to correspond to the positions on the deck board surface along the side wall of the central beam 12. The trace of one gas injection hole appearing in FIG.
[0024]
As is apparent from FIGS. 1 and 2, the base portion of the side wall 12 a of the central girder 12 at a position passing through the gas injection hole of the mold, that is, the connecting portion between the side wall 12 a and the deck board 11 is formed as a reinforcing rib 13. A rib 17 having a lower height (preferably about 10 mm in height) is formed along the side wall 12a, thereby increasing the thickness of the side wall base of the girder 12. When the molten resin is injected from the gas injection hole described above or from the dedicated hole for injection of the molten resin and the pallet forming member 10 is injection-molded, before the inside of the reinforcing rib 13 is solidified, air or A suitable gas such as nitrogen is injected.
[0025]
The gas injected from the above-described gas injection hole passes through the thick portion at the side wall base portion of the central girder 12 and enters the reinforcing ribs 13b to make the inside hollow. Therefore, the hollow part shown by the code | symbol 18 in FIG. 3 is a conduction path of the injection gas formed in the thick part in the side wall base part of the center girder 12, and this conduction path 18 is the hollow part 19 in each reinforcement rib 13b. And everything is in communication.
[0026]
In this way, when the molten resin is injected into the mold and molded, the hollow portion is formed in the reinforcing rib by blowing a gas such as air or nitrogen before the molten resin injected into the mold is solidified. Is well known as a gas injection method, and a detailed description thereof will be omitted.
[0027]
Since the internal pressure of the gas blown into the reinforcing rib 13 acts equally on the inner wall of the mold part, the thickness S of the molded hollow rib 13b is almost constant and the thickness is extremely unevenly distributed. Absent. By forming the hollow portion 19 in the reinforcing rib in this manner, effects such as weight reduction of the synthetic resin pallet and reduction of molding time for reducing dimensional fluctuation during molding can be obtained. Depending on the gas flow, the rib 13b may not be completely hollow, or the resin may remain in a partition wall shape.
[0028]
The amount of gas injected into the reinforcing rib during the injection molding of the pallet forming member 10 is adjusted according to 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.
[0029]
By the way, the hollow rib 13b and the solid ribs 13a and 13c constituting the reinforcing rib 13 are all connected. Therefore, it is conceivable that the injected gas flows into the solid rib forming mold portion and becomes hollow. However, the gas injected into the mold does not flow into the rib having a predetermined thickness or less. Therefore, as long as the width of the solid rib 13a, that is, the thickness is formed in the range of about 4 to 7 mm, the gas is hollow. Become solid without losing.
[0030]
Next, the structure at the end of the spar 12 adjacent to the fork insertion port 15, in other words, at the ends of the spar 12 positioned on both sides of the fork insertion port 15 will be described. Three relatively small sealed hollow portions 20 are formed inside the end portion of the beam 12 adjacent to the fork insertion port 15 so as to divide the internal space of the beam 12.
[0031]
These sealed hollow portions 20 are defined by partition walls 21 that cooperate with the side walls 12a and 12b and the end walls 12c at the ends of the spar 12. The partition wall 21 includes a first partition portion 21a formed therebetween so as to be substantially orthogonal to the side walls 12a and 12b of the spar along the longitudinal direction of the fork insertion hole 14, that is, the fork insertion direction. In order to further divide the space portion defined by the partition portion 21a and the side walls 12a, 12b and the end wall 12c of the beam 12, two second partition portions 21b parallel to the fork insertion direction are formed. Thereby, about the edge part of the girder 12 adjacent to the fork insertion port 15, the intensity | strength with respect to the impact from a fork insertion direction can be improved.
[0032]
By the way, the injection molding conditions of the pallet forming member 10 may be normal conditions. For example, when high-density polyethylene is used as the material, the melting temperature (cylinder temperature) is 200 to 250 ° C., and the injection rate is about 2000 to 5000 cc / sec. Conditions are preferred. The synthetic resin constituting the pallet is generally a polyolefin such as polyethylene, polypropylene, or ethylene-propylene copolymer. It goes without saying that other resins may be used in some cases.
[0033]
Furthermore, it goes without saying that additives such as colorants and fillers may be used as appropriate. Furthermore, conventionally known foaming agents including organic or inorganic substances that are usually used may be mixed into these synthetic resins to form foams. In this case, the expansion ratio is preferably about 1.05 to 1.4 times. In this case, the apparent density of the entire pallet is preferably about 0.65 to 0.9 times the density of the raw synthetic resin.
[0034]
In the synthetic resin pallet according to the above-described embodiment, the reinforcing rib 13 provided on the inner side of the pallet forming member is formed so as to extend in a direction parallel to and perpendicular to the fork insertion direction. Except for the solid ribs 13a formed at the edge of the deck board 11 along the mouth, there is no reason to limit the extending direction of the reinforcing ribs to such a direction.
[0035]
Moreover, the partition wall 21 which forms the airtight hollow part 20 in the edge part of the girder 12 adjacent to the fork insertion port 15 is substantially orthogonal to the side walls 12a and 12b of the girder 12 along the fork insertion direction as shown in FIG. Fork to further divide the first partition 21a formed between them and the space defined by the first partition 21a and the side walls 12a, 12b and end walls 12c of the spar 12 It can also be comprised from the 2nd 2nd partition part 31b inclined with respect to the insertion direction.
[0036]
As shown in FIG. 5, when the inclination angle α is 0 degree, the configuration of the embodiment shown in FIG. 1 is adopted. Therefore, the inclination angle can be set in a range up to 90 degrees excluding 0 degree. However, in the case of 90 degrees, the second partition portion 31 b is removed because it is parallel to the end wall 12 c of the beam 12. Therefore, if this angle α is expressed by an inequality, 0 degree <α <90 degrees.
[0037]
1 and 4, reference numeral 22 indicates that when the synthetic resin pallet 10 is used, when the fork is inserted into the fork insertion hole 14, the fork and the synthetic resin pallet 10 are connected. This is a rubber grommet for slip prevention that is press-fitted into a hole formed in the hollow rib 13 so as not to cause relative slip.
[0038]
【The invention's effect】
As described above, according to the synthetic resin pallet of the present invention, the solid reinforcing rib is provided on the deck board edge along the fork insertion port which is easily affected by the fork, and is formed on the inner surface of the other deck board. Reinforced ribs are hollow ribs, and a relatively small sealed hollow part is formed inside the spar at the end of the spar adjacent to the fork insertion port to reduce the weight of the synthetic resin pallet. While improving the bending strength, it is possible to improve the impact strength of the reinforcement ribs of the fork insertion slot and the end of the girder that are susceptible to impact, thereby further improving the durability of the synthetic resin pallet. it can.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a further quarter portion of an upper half pallet forming member in a synthetic resin pallet according to an embodiment of the present invention formed by integrating vertically divided pallet forming members. It is.
FIG. 2 is a cross-sectional view showing a hollow reinforcing rib by cutting the pallet forming member shown in FIG. 1 along line 2-2.
FIG. 3 is a cross-sectional view showing a conduction path for cutting the pallet forming member shown in FIG. 1 along line 3-3 and injecting gas into the hollow portion of the reinforcing rib.
4 is a cross-sectional view showing a further quarter portion of an upper half pallet forming member similar to FIG. 1 according to another embodiment of the present invention. FIG.
5 is a partial cross-sectional view showing, in an enlarged manner, an end structure of a spar adjacent to a fork insertion port in the pallet forming member of the embodiment shown in FIG. 4;
[Explanation of symbols]
10 Pallet forming member 11 Deck board 12 Girder (leg)
12a Girder side wall 12b Girder side wall 12c Girder end wall 13 Reinforcement rib 13a Solid rib 13b Hollow rib 13c Solid rib for connection 14 Fork insertion hole 15 Fork insertion hole 16 Resin injection hole mark 17 Rib 18 Conducting path 19 Reinforcement rib Hollow part 20 Sealed hollow part 21 Partition wall 21a First partition part 21b Second partition part 31b Second partition part

Claims (4)

A pallet forming member having a shape obtained by dividing the pallet into upper and lower parts is formed by injection molding, and these are made of a synthetic resin pallet formed by welding and opposing each other,
The pallet forming member includes a deck board forming a loading surface, a thin girder provided on the deck board, and reinforcing ribs provided vertically and horizontally on the inner surface of the deck board, and the reinforcing ribs are A solid rib formed on the edge of the deck board along the fork insertion port of the synthetic resin pallet, and a hollow rib formed on the inner surface of the deck board other than the edge, and the girder is the fork Provided with a plurality of small sealed hollow portions so as to divide the internal space of the girder inside the end adjacent to the insertion port,
A first partition portion formed between the side walls of the spar along a fork insertion direction in which a partition wall forming the sealed hollow portion in the end portion of the spar is inserted from the fork insertion port; and the first partition And at least one second partition portion parallel to the fork insertion direction so as to further divide the space portion defined by the portion and the end wall of the beam,
The solid rib formed on the edge of the deck board along the fork insertion port of the synthetic resin pallet is spaced apart from the adjacent hollow rib provided along the solid rib by a predetermined distance. A synthetic resin pallet characterized by being connected by a plurality of solid connecting ribs arranged in a row . 2. The synthetic resin pallet according to claim 1, wherein a width of the solid rib is smaller than a width of the hollow rib. A first partition portion formed between the side walls of the spar along a fork insertion direction in which a partition wall forming the sealed hollow portion in the end portion of the spar is inserted from the fork insertion port; and the first partition And at least one second partition portion formed at an angle α with respect to the fork insertion direction so as to further divide the space portion defined by the portion and the side wall of the girder, and the angle α is 0 degrees. The synthetic resin pallet according to claim 1 or 2 , wherein <α <90 °. The thickness of the girder is about 3 mm to 7 mm, the width of the hollow rib is about 8 mm to 40 mm, and the width of the solid rib is smaller than the width of the hollow rib. The synthetic resin pallet according to any one of 1 to 3 .

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