JP4592019B2 - Plastic pallet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a synthetic resin pallet for forklifts used when transporting and storing a load, and more particularly to a synthetic resin pallet that prevents a bead from protruding to the outer surface that occurs during welding.

  Synthetic plastic pallets for forklifts used for storing and transporting luggage have hollow struts between the upper deck board and lower deck board, and are attached to both ends and the middle of the deck board. The space surrounded by the arranged support column and the upper and lower deck boards is used as the fork insertion port of the forklift.

  As one method for manufacturing a synthetic resin pallet, there is a method in which parts divided into a plurality of parts are integrally welded to form a pallet. For example, there is a method in which the upper and lower parts in a state where the pallet is divided at substantially the middle position of the support column are formed in advance, and the end surfaces of the support columns of the upper and lower two parts are butted and welded together to form them integrally. The pallet by butt welding has a hollow structure in which reinforcing ribs are provided on the lower surface of the deck board and the side of the support column is closed.

  A synthetic resin pallet is excellent in corrosion resistance and contamination resistance, but has a problem that it is inferior in bending strength and impact strength compared with a wooden pallet. In particular, when a pallet is manufactured by butt welding two parts molded in advance, the strength of the welded part is inevitably lowered, and a bead protrudes from the side of the welded part. If the bead protrudes, not only the appearance of the product is deteriorated, but also the hook may be caught when the fork is inserted, which may cause trouble in use. For this purpose, post-processing such as removing the bead by cutting must be performed.

In order to solve the above problem, in Japanese Utility Model Laid-Open No. 53-135483, the welding surface of the welding member is formed to be thicker than the other portion, and a chamfered portion is provided on one side surface. A structure of a welded portion of a synthetic resin product in which a groove is formed by a portion and a bead is accommodated in the groove has been proposed.
Japanese Utility Model Publication No. 53-135483

  However, in the structure described in Japanese Utility Model Laid-Open No. 53-135483, the thickness of the welded surface does not change, so the material cannot be reduced. In a synthetic resin product, the ratio of material cost occupies a large specific gravity in the unit price of the product, so it was a problem to maintain load resistance while reducing the material.

  Further, in the structure described in the above publication, the amount of the bead protruding by welding does not change so much, so that the groove formed by the chamfered portion must be enlarged in order to suppress the amount of bead protruding to the outer surface. There is.

  The present invention has been made in view of the present situation, and in a pallet formed by integrally joining two parts by butt welding, a bead generated at the time of butt welding is prevented from protruding to the outer surface, and at the welding portion. Another object of the present invention is to provide a synthetic resin pallet having sufficient welding strength.

In order to achieve the above object, the present invention is configured as follows. That is, the synthetic resin pallet according to the present invention welds the upper part and the lower part, which are divided and formed at substantially the middle position of the column part connecting the upper deck board and the lower deck board, with the end surfaces of the column parts butted. In the synthetic resin pallet formed integrally by the above, the butt surface of the support part of the upper part and the lower part which are divided and formed is provided inside by providing a notch on the outer peripheral surface side of the peripheral wall of the support part. Protrusions serving as secondary welds are formed, and reinforcing ribs and projecting pin receivers serving as primary welds are provided on the inner surface of the peripheral wall of the support column so as to project beyond the projecting parts. The reinforcing rib and the protruding pin receiving portion are formed in a step shape that is continuous with the protruding portion in the cross section, and when the butt welding is performed, the reinforcing rib of the upper part that becomes the primary welding portion and The protruding pin holder and the reinforcing rib of the lower part and the protruding pin holder are welded, and then the protruding part of the upper part and the protruding part of the lower part which are the secondary welding parts are welded. It is characterized by being housed in a groove formed by abutting the notch of the part and the lower part.

  The planar shape of the protruding pin receiver is not particularly limited, but is preferably formed in a circular shape. Moreover, it is preferable that the protrusion dimension from the notch surface of the said protrusion part is larger than the protrusion dimension from the protrusion part end surface of a reinforcement rib and a protrusion pin receiver. Further, the thickness of the protruding portion can be approximately one third of the thickness of the peripheral wall of the support column.

  In the end surface of the support column, the protrusion, the reinforcing rib, and the protruding pin receiver are formed in a stepped shape in the cross section, so that the protruding amount of the bead to the outer peripheral surface can be reduced and the groove formed by the notch By storing in, it can prevent that a bead protrudes to an outer peripheral surface.

  Even when the peripheral wall of the column is relatively thin, it is possible to maintain sufficient impact strength and load resistance by providing a reinforcing rib on the inner peripheral surface and welding the protruding pin holder in the same way as the reinforcing rib. it can.

  Hereinafter, embodiments of the synthetic resin pallet according to the present invention will be described in detail. The illustrated synthetic resin pallet P is a four-way pallet, provided with support columns 4 at the four corners of the upper deck board 2 and the lower deck board 3, and with intermediate support columns 5 between the support columns 4 at the four corners, Further, a central support column 6 is provided at the center of the deck board.

  A space surrounded by the support columns 4 and 5 and the upper and lower deck boards 2 and 3 is a fork insertion port 7. The lower deck board 3 is provided with a relatively large opening 8 that enables use of a hand lift or a pallet truck.

  The upper deck board 2 and the lower deck board 3 are formed by lattice-like ribs 15 provided in parallel to the side surfaces, and the column parts 4, 5 and 6 are hollow. The upper deck board 2 and the lower deck board 3 are also formed by lattice-like ribs 15 on the upper and lower surfaces of the support columns 4, 5 and 6, and therefore the upper and lower surfaces of the support columns 4, 5 and 6 are completely Is not closed.

  The pallet P is divided in advance in a horizontal direction at a substantially middle position between the support columns, and is formed into an upper part 10 having the upper deck board 2 and a lower part 11 having the lower deck board 3, and then the upper part 10. And the lower part 11 are integrally molded by butting and welding at the end face of the support column.

  Further, the upper part 10 will be described. As shown in FIGS. 3 and 4, the upper part 10 is composed of an upper deck board 2a, four pillars 4a, an intermediate pillar 5a, and a central pillar 6a. Further, the lower part 11 will be described. The lower part 11 includes a lower deck board 2b, four corner support parts 4b, an intermediate support part 5b, and a center support part 6b. A synthetic resin pallet P is formed by welding the butted surfaces of the support columns.

  As the resin used for the synthetic resin pallet P, polystyrene, polyethylene, polypropylene, vinyl chloride, ABS resin, or the like can be used, and a foaming agent, a filler, or the like may be added as necessary.

  Next, the structure of the abutting surface in the column part of the upper part 10 and the lower part 11 which is a feature of the present invention will be described. The support columns 4a and 4b, the support columns 5a and 5b, and the support columns 6a and 6b are symmetrical and basically have the same configuration. Therefore, the support columns 4a and 4b will be described, and the support columns 5a and 5b. 6a and 6b are denoted by the same reference numerals and description thereof is omitted.

  The support | pillar part 4 is a planar substantially rectangular hollow body, Comprising: As shown in FIG. 6, it is formed of the surrounding wall 41 which has thickness T1. The abutting surface of the peripheral wall 41 is formed with a protruding portion 43 that protrudes inwardly by providing a notch 42 on the outer peripheral surface side, and the protruding portion 43 is a secondary member when welding, as will be described later. It becomes a welding part.

  When the thickness of the peripheral wall 41 is T1, the protrusion height of the protrusion 43 is L1, and the wall thickness of the protrusion 43 is T2, the protrusion height L1 ≦ the wall thickness T1, T2 <T1, and T2≈T1. × 1/3 is preferable. Since the protruding portion 43 forms a part of the peripheral wall 41, it forms the inside of the end surface of the peripheral wall 41.

  Further, a reinforcing rib 45 and a protruding pin receiver 46 are provided on the inner surface side of the peripheral wall 41 so as to be orthogonal to each other. After the molten resin is injected into the mold and molded, the molded product is taken out from the mold by projecting an ejection pin provided in the mold. The ejection pin receiver 46 is a part that receives the ejection pin. However, many are provided in consideration of the structure and thickness of the molded product.

  In the embodiment, the reinforcing rib 45 is an I-shaped reinforcing rib 45a or a T-shaped reinforcing rib 45b, and the protruding pin receiver 46 is a circular protruding pin receiver 46a in this embodiment. It is not limited. In this embodiment, the protruding pin receiver 46 also functions as a reinforcing rib. The reinforcing rib 45 and the protruding pin receiver 46 further protrude from the tip of the protruding portion 43. If the protruding height is L2, L2≈T2.

  Therefore, as is apparent from FIG. 6, the outer surface of the peripheral wall 41, the outer surface of the protrusion 43, and the outer surfaces of the reinforcing rib 45 and the protruding pin receiver 46 are formed stepwise in cross section. The reinforcing rib 45 and the protruding pin receiver 46 serve as a primary welded portion when butt welding.

  Further, as shown in FIG. 5, welding ribs 47 having the same height may be provided on the side surface of the protruding pin receiver 46. Thus, by providing the reinforcing rib 47, the protrusion by the protrusion pin when taking out from the mold can be performed in a stable state, and the impact strength of the peripheral wall 41 is improved.

  The structure of the abutting surface in the column portion of the upper part 10 has been described above. However, the corresponding abutting surface in the lower part 11 is formed symmetrically and is merely upward.

  Next, the butt welding of the upper part 10 and the lower part 11 having the above configuration will be described. As described above, the projecting portion 43 and the reinforcing rib 45 and the projecting pin 46 that further project from the projecting portion 43 are formed in a step shape on the abutting surfaces of the upper component 10 and the lower component 11.

  In order to manufacture the pallet, first, the butt surfaces of the upper part 10 and the lower part 11 may be melted and butt welded. Melting of the butted surfaces melts the protruding portion 43, the reinforcing rib 45, and the protruding pin receiver 46, and at this time, it does not melt to the notched surface of the notch 42, or does not melt as much as the reinforcing rib and the protruding pin receiver. First, when butt welding is performed, as shown in FIG. 7, first, the reinforcing rib 45 and the protruding pin receiver 46 serving as the primary welding portion protruding at the position of the tip end are welded. Further, when the welding pressure is increased, the protrusion 43 serving as the secondary welding portion is welded.

  When the reinforcing rib 45 serving as the primary welded portion and the protruding pin receiver 46 are welded, the bead protrudes slightly toward the protruding portion 43, but the protruding bead is welded together with the protruding portion 43. The bead protrudes when the protrusion 43 is welded, but the notch 42 forms a groove in the upper part 10 and the lower part 11 and functions as a bead relief allowance. It does not protrude. Further, by providing a primary welded portion and a secondary welded portion and sequentially welding them, the amount of protruding bead can be reduced.

  Even if the bead protrudes from the outer surface of the support column, the amount of the bead is small and does not hinder the use. Therefore, post-processing after welding is unnecessary, and equipment for performing post-processing is also unnecessary. On the other hand, welding on the butting surface of the peripheral wall 41 is performed only by the protrusion 43, but the reinforcing rib 45 and the protruding pin receiver 46 are butted and welded to the inner surface side of the peripheral wall 41, so that sufficient welding strength can be maintained. .

The right half of the synthetic resin pallet according to the present invention is a front view, and the left half is a longitudinal sectional view taken along line 2A-A in FIG. The right half is a plan view, and the left half is a cross-sectional view taken along the line BB in FIG. 1B. FIG. 3 is a partially enlarged view of the upper part taken along line AA in FIG. 2. FIG. 3 is a partially enlarged view of the upper part taken along a line in FIG. 2C-C. It is the top view which expanded partially the support | pillar part of the four corners of a lower part. It is sectional drawing which expanded partially in the support | pillar part of the four corners of an upper part. FIG. 7 (a) shows a state before welding, FIG. 7 (b) shows a state in which the reinforcing rib and the protruding pin receiver are welded, and FIG. 7 (c) shows a welding process. The protruding portion is welded and the bead is housed in the groove.

Explanation of symbols

2: Upper deck board 3: Lower deck board 4: Four pillars 5: Middle pillar 6: Middle pillar 7: Fork insertion port 8: Opening 10: Upper part 11: Lower part 15: Lattice Rib 41: Peripheral wall 42: Notch 43: Projection 45: Reinforcement rib 46: Projection pin receiver

Claims (4)

Synthetic resin pallet made by integrally forming the upper part and the lower part, which are divided and molded at approximately the middle position of the column part connecting the upper deck board and the lower deck board, by butting the end surfaces of the column parts. Then, on the abutting surface of the column part of the upper part and the lower part which are divided and formed, a protrusion serving as a secondary welding part is formed inside by providing a notch on the outer peripheral surface side of the peripheral wall of the column part, Further , a reinforcing rib and a protruding pin receiver which are primary welded portions are provided on the inner surface of the peripheral wall of the support column so as to protrude from the protruding portion, and in the portion of the reinforcing rib and the protruding pin receiver, In the cross section, it is formed in a continuous step shape with the projecting portion, and when the butt welding is performed, the reinforcing rib and the projecting pin receiver of the upper part and the reinforcing rib and the projecting part of the lower part which become the primary welded part are formed. Weld the receiving pin holder, then weld the protruding part of the upper part and the protruding part of the lower part, which will be the secondary welding part, and the bead generated by welding will abut the notch of the upper part and the lower part A synthetic resin pallet characterized by being housed in a groove formed by the above-described method.   2. The synthetic resin pallet according to claim 1, wherein the protruding pin receiver is formed in a planar circular shape.   The synthetic resin pallet according to claim 1 or 2, wherein a protruding dimension of the protruding part from the cut-out surface is larger than a protruding dimension of the reinforcing rib and the protruding pin receiver from the protruding part end surface.   The synthetic resin pallet according to any one of claims 1 to 3, wherein the thickness of the protruding portion is approximately one third of the thickness of the peripheral wall of the support column.

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