JP4856443B2 - Method for welding molded product and method for welding pallet - Google Patents

Description

  The present invention relates to a method for welding molded products and a method for welding pallets, which are used for transporting loads and the like by forklifts, for example.

  Conventionally, examples of this type of molded article include the following (see, for example, Patent Document 1). That is, as shown in FIG. 11, the molded product (pallet 100) described in Patent Document 1 has a pair of upper and lower pallet forming members 101. As shown in FIGS. 11 and 12, each pallet forming member 101 includes a flat board 102, a cylindrical girder 103 formed at both ends and an intermediate part inside the board 102, and an inside of the board 102. The reinforcing rib group 104 is provided to intersect vertically and horizontally. The pallet 100 is configured such that the pallet forming members 101 are fixed to each other by welding the cylindrical beam portions 103 of the pallet forming members 101.

As shown in FIG. 12, each cylindrical girder 103 in the pallet 100 is provided with a girder reinforcing structure 105. The girder reinforcing structure 105 includes a reinforcing rib 105a that is provided in a substantially central portion of the cylindrical girder 103 and has an annular shape, and radial ribs 105b that extend radially from the outer periphery of the reinforcing rib 105a. And as shown in FIG. 13, the height H of this girder reinforcement structure part 105 (reinforcement rib 105a) is formed slightly higher than the height h of the peripheral part 103a of the cylindrical girder part 103. As shown in FIG. For this reason, when the pair of upper and lower pallet forming members 101 are fixed to each other, as shown in FIG. 14, the molten resin protrudes from the end surface (butting surface) of the double girder reinforcing structure 105 (reinforcing rib 105a). Although the burr 106 is formed, all of the burr 106 is present inside the cylindrical girder 103 and cannot be visually recognized from the outside, so that the appearance of the product is not affected. Further, a gap S is formed between the peripheral edge portions 103 a of the cylindrical spar portions 103 of both pallet forming members 101, and the peripheral edge portions 103 a of the cylindrical spar portions 103 are not easily welded to each other. Therefore, the burr is hardly exposed to the outside of the cylindrical girder 103, and the deterioration of the appearance is suppressed as much as possible.
Japanese Patent Laid-Open No. 11-124137

  However, in the conventional pallet 100, when the peripheral edge portions 103a of the cylindrical girder portions 103 of both pallet forming members 101 are partially welded, a burr 108 is formed inside the gap S as shown in FIG. . Certainly, the burr 108 does not protrude outside the cylindrical girder 103, but is easily visible from the outside on the side wall side of the pallet 100. For this reason, it cannot be said that the conventional pallet 100 is sufficiently improved in appearance, and there is room for improvement in this respect.

  The present invention has been made in view of such conventional circumstances, and an object of the present invention is to provide a method for welding a molded product and a method for welding a pallet, which can easily improve the appearance.

In order to achieve the above object, the method of welding a molded product according to the first aspect of the present invention is such that both end surfaces of the welded portions of a pair of molded members disposed opposite to each other are welded together. In the welding method of the molded product to which the two are connected, the step of heating and melting the end surfaces of the welded portions of the pair of molded members, and the end surfaces of the welded portions are opposed to each other and pressed while being connected, A step of integrating the molded members, and as at least one molded member of the pair of molded members, at least a part of the welded portion is a base material layer made of a base material, and a surface side of the base material layer Na sectional plurality of layers with at least shade, or different additional layers of material from the uterine material layer while being added to, cross plurality layer portion of the welded portion, the base material layer toward the end portion side reduced Formed to be And summarized in that the use of the molded member that is the additional layer is formed from the surface side to the end face of the welded portion in a plane more layer portion.

  Normally, when welding the welded portions of such a pair of molded members, the butted portion (welded portion) is eluted sideways by heating the welded portion (the portion including the end face) of the molded member. Since the parts melt and the melted parts are pressed against each other by a considerable pressing force, the welded portion is further eluted in a direction perpendicular to the pressing direction of the pressing force. That is, the welded portion of the pair of molded members is eluted on the surface as compared with other portions of the molded member. For example, when the end surface of the welded portion is configured to have a plurality of cross-sectional layers in which an additional layer is added to the surface side of the base material layer, the elution portion is brought into contact with the surface of the additional layer by elution of the base material layer. It is possible to be exposed. In such a case, a base material layer different from the color tone or material of the additional layer is locally eluted on the surface of the additional layer, and the appearance is deteriorated.

  On the other hand, in this invention, at least one part of the end surface of the welding part which makes a cross-sectional multiple layer is comprised with the additional layer. In such a case, when melting the end surfaces of the welded portions of each molded member when the welded portions of both molded members are heat welded, the surface is obtained by pressing the melted welded portions by applying heat to the additional layer. The additional layer elutes. At this time, the amount of elution of the base material layer is reduced by the amount of heat applied to the additional layer. As a result, even if the eluted portion of the additional layer is removed, the base material layer does not elute on the surface of the additional layer. Therefore, a molded product having a flat and good appearance can be obtained which is unified with the color tone or material of the additional layer.

According to a second aspect of the present invention, there is provided a method for welding a pallet comprising: a pair of pallet members having a plate-like material and a plurality of cylindrical girder portions extending from the plate-like material; In the pallet welding method in which both the pallet members are connected by welding the end surfaces of the welded portions of the cylindrical girder, the end surfaces of the welded portions of the pair of pallet members are heated respectively. And melting and a step of making the pair of pallet members integrated by making the end faces of the welded portions face and press against each other, and welding as the pallet member in the cylindrical girder portion At least a portion of the section is, Shi name and the base material layer made of the base material, a cross-section a plurality of layers of at least the color tone or a different additional layer of material from the uterine material layer while being applied to the surface side of the uterine material layer , In cross-section multi-layer part Only some kicking the surface side of the end face of the weld portion is summarized as the use of the pallet member covered from the front side by the additional layer.
According to a third aspect of the present invention, there is provided a method of welding a pallet comprising: a pair of pallet members having a plate-like material and a plurality of cylindrical girder portions extending from the plate-like material; In the pallet welding method in which both the pallet members are connected by welding the end surfaces of the welded portions of the cylindrical girder, the end surfaces of the welded portions of the pair of pallet members are heated respectively. And melting and a step of making the pair of pallet members integrated by making the end faces of the welded portions face and press against each other, and welding as the pallet member in the cylindrical girder portion At least a part of the portion comprises a base material layer made of a base material, and a plurality of cross-sections of the base material layer and an additional layer having a color tone or a material different from that of the base material layer. For cross-section multiple layers With the end face of kicking the welded portion is formed from said additional layer and the base material layer, the end face of the additional layer to the end face of the base material layer is summarized in that projecting.
According to a fourth aspect of the present invention, there is provided a method for welding a pallet comprising: a pair of pallet members having a plate-like material and a plurality of cylindrical girder portions extending from the plate-like material; In the pallet welding method in which both the pallet members are connected by welding the end surfaces of the welded portions of the cylindrical girder, the end surfaces of the welded portions of the pair of pallet members are heated respectively. And melting and a step of making the end faces of the welded portions face each other and pressing them together to integrate the pair of pallet members, and forming the pallet members by two-color molding A pallet member, wherein a part of the welded portion of the cylindrical girder is formed with a concave portion on the surface side and is added to the base material layer made of a base material and the concave portion of the base material layer and the same. The color of the base material layer The base material layer in the cross-sectional multi-layer part is formed thinner than the base material layer in the other part of the cylindrical girder, and the welding in the cross-sectional multi-layer part The gist is to use a pallet member in which the additional layer is formed on the end surface of the portion from the surface side.

  Usually, when welding the welding parts of such a cylindrical girder part, the butting part (welding part) elutes to the side by the heating with respect to the welding part (part containing an end surface) of a cylindrical girder part. Since the parts melt and the melted parts are pressed against each other by a considerable pressing force, the welded portion is further eluted in a direction perpendicular to the pressing direction of the pressing force. The welded portion of the cylindrical spar is eluted on the surface as compared with other parts of the cylindrical spar. For example, when the end surface of the welded portion is configured to have a plurality of cross-sectional layers in which an additional layer is added to the surface side of the base material layer, the elution portion is brought into contact with the surface of the additional layer by elution of the base material layer. It is possible to be exposed. In such a case, a base material layer different from the color tone or material of the additional layer is locally eluted on the surface of the additional layer, and the appearance is deteriorated.

  On the other hand, in this invention, at least one part of the end surface of the welding part which makes a cross-sectional multiple layer in a cylindrical girder part is comprised with the additional layer. In such a case, when the end surfaces of the welded portions of the cylindrical girders are melted when the welded portions of the cylindrical girders are heat-welded, the heat is applied to the additional layer and the melted welded portions are pressed against each other. Thus, the additional layer on the surface elutes. At this time, the amount of elution of the base material layer is reduced by the amount of heat applied to the additional layer. As a result, even if the eluted portion of the additional layer is removed, the base material layer does not elute on the surface of the additional layer. Therefore, a flat and good-looking palette can be obtained which is unified with the color tone or material of the additional layer.

  According to the method for welding molded products and the method for welding pallets of the present invention, it is possible to improve the appearance.

Hereinafter, an embodiment embodying the welding method of the present invention will be described with reference to the drawings.
First, a pallet as a molded product will be briefly described. The base material of the pallet of this embodiment is formed from a synthetic resin of recycled material. As shown in FIGS. 1 and 2, the pallet 10 is configured by integrating a pair of upper and lower pallets 10 a and 10 b (molded members 10 a and 10 b) by welding. In the present specification, of the pair of pallets 10a and 10b, the upper pallet is the upper pallet 10a, and the lower pallet is the lower pallet 10b. Moreover, let the site | part formed from the said base material be a base material layer in pallets 10a and 10b.

  The pallet 10 includes an upper plate-like material 11 constituting the upper wall of the upper pallet 10a, a lower plate-like material 12 constituting the lower wall of the lower pallet 10b, and a plurality of these plate-like materials 11, 12 connected to each other. And a cylindrical girder part 14. Both the upper plate-like material 11 and the lower plate-like material 12 fulfill the function of placing a load. Since the lower pallet 10b is obtained by rotating the upper pallet 10a by 180 ° and both have the same configuration, only the configuration of the upper pallet 10a will be described in this specification.

  As shown in FIGS. 2 to 5, the upper pallet 10 a includes an upper plate-like material 11 having a substantially square plate shape, and a square cylindrical tubular girder portion 14 extending downward in the same plate-like material 11. And side wall ribs 15 that hang downward from the side edges of the upper plate-like material 11 and that connect the adjacent cylindrical girders 14. A plurality of crosspieces 16 are extended in a mesh pattern on the entire back surface of the upper plate-like material 11, and the surface strength of the upper plate-like material 11 is enhanced by these crosspieces 16.

  As shown in FIG. 3, the cylindrical girder portion 14 includes a corner girder portion 14 </ b> A disposed at the four corners of the upper plate-like material 11 and a center between each corner girder portion 14 </ b> A at the side edge of the upper plate-like material 11. The intermediate girder part 14 </ b> B arranged at the center and the central girder part 14 </ b> C arranged at the center of the upper plate-like material 11. Then, as shown in FIG. 6, the upper pallet 10a and the lower pallet 10b are arranged so as to face each other vertically, and the digit portions 14A, 14B, 14C of the pallets 10a, 10b are aligned with each other. By thermally welding, the two plate-like members 11 and 12 are connected to each other to form the pallet 10. In this state, a fork insertion hole 21 is provided between each corner beam portion 14A and intermediate beam portion 14B (see FIG. 2). In addition, since the lower end part of each girder part 14A, 14B, 14C of the upper pallet 10a and the upper end part of each girder part 14A, 14B, 14C of the lower pallet 10b are parts contributing to both welding, In the specification, it is defined as “welded part”. Further, in FIG. 6, illustration of the crosspiece 16 is omitted.

  Among these plurality of cylindrical girders 14, the corner girders 14A and the intermediate girders 14B are, as shown in FIG. 3, a surface wall 23 constituting a part of the peripheral wall 20 of the pallet 10, the fork insertion holes 21, and the like. A back wall 24 extending in the same direction (a direction orthogonal to the front wall 23), and a distance between the left and right of the fork insertion hole 21 provided between the front wall 23 and the back wall 24 is the opening end. And an inclined wall 25 that is gradually reduced.

  As shown in FIGS. 4 and 5, the peripheral wall 20 of the pallet 10 (the surface wall 23 of the corner spar 14A, the surface wall 23 of the intermediate spar 14B, and the side wall rib 15) is formed with a recess 27 over the entire surface. ing. In the recess 27, an additional layer 20b made of a synthetic resin of virgin material is formed. The virgin material used for the additional layer 20b is colored with a coloring material and has a color tone different from that of the base material layer 20a of the peripheral wall 20. Therefore, the entire peripheral wall 20 of the pallet 10 has a cross-section of a base material layer 20a integrally extending from the upper plate member 11 and an additional layer 20b added to a recess 27 provided in the base material layer 20a. It is comprised so that a layer structure (cross-sectional multi-layer structure) may be made. Here, the “cross section” means a cross section parallel to the upper plate member 11 (lower plate member 12).

  As shown in FIGS. 5 and 6, in each surface wall 23 of the corner beam portion 14 </ b> A and the intermediate beam portion 14 </ b> B (site having a two-layer cross section), the base material layer 20 a has a tip (an end surface on the welded portion side, Hereinafter, the cross-sectional area is reduced toward the welded portion side end face 28). As shown in FIGS. 3 and 6, in each surface wall 23 of the corner beam portion 14 </ b> A and the intermediate beam portion 14 </ b> B, the welded portion side end surface 28 is constituted only by the additional layer 20 b. That is, the end surface T of the base material layer 20a is entirely covered with the additional layer 20b in the welded portion of the surface wall 23 of the corner beam portion 14A and the intermediate beam portion 14B, and the base material layer is formed on the end surface 28 of the welded portion side. 20a never exists.

  Moreover, as shown in FIG. 6, from the viewpoint of making the two pallets 10a and 10b suitable for welding, the end faces of the cylindrical girders 14A, 14B, and 14C in the upper pallet 10a are positioned on the same plane P. It is preferable. That is, it is preferable that the heights of the cylindrical beam portions 14A, 14B, and 14C are all set to be the same.

Hereinafter, the forming method and the welding method of the pallets 10a and 10b of the present embodiment will be sequentially described.
First, a method of forming a portion (a surface wall 23 of the corner beam portion 14A and the intermediate beam portion 14B) having a two-layer structure in the pallets 10a and 10b will be described. The pallets 10a and 10b are molded by a two-color molding method using an injection molding machine (not shown). Here, the step of adding the additional layer 20b to the base material layer 20a from the step in which the peripheral wall 20 of the upper pallet 10a (the lower pallet 10b) before the formation of the additional layer 20b is formed of the base material layer 20a by injection molding. The forming method up to will be described with reference to FIG. This two-color molding method is performed using the fixed mold 31, the movable mold 32, and the slide core 33.

  The fixed mold 31 includes a first gate (not shown) through which a primary thermoplastic material (synthetic resin for recycled material) that forms the base material layer 20a circulates, and a secondary thermoplastic material (coloring material that forms the additional layer 20b). A part of the second gate 35 (fixed mold side second gate 35a) through which the added virgin material synthetic resin) flows is formed. The slide core 33 is formed with a core-side second gate 35b that can communicate with the fixed-type second gate 35a by sliding the slide core 33 in a predetermined direction. In addition, if desired two-color molding is possible, the structure of these various metal mold | dies 31,32,33 is not specifically limited.

  When the base material layer 20a is molded, as shown in FIG. 7A, primary thermoplasticity is passed through the first gate into the first cavity K1 formed by the fixed die 31, the movable die 32 and the slide core 33. The material is injected (first step). In the first step, the tip of the second gate 35 (tip of the core-side second gate 35) is sealed by the movable die 32. Thus, after injecting a primary thermoplastic material in the 1st cavity K1, the intermediate molded object in which the surrounding wall was comprised only from the base material layer 20a through the conventionally well-known pressure-holding process and cooling process is shape | molded.

  Thereafter, the slide core 33 in close contact with the side surface of the base material layer 20a is moved in a direction away from the base material layer 20a (in the direction of the arrow X) by a driving means (not shown), whereby the second cavity shown in FIG. K2 appears. At this time, as described above, since the tip of the second gate 35 formed on the slide core 33 is blocked by the movable mold 32 in the first step, the primary thermoplastic resin injected into the first cavity K1. There is no possibility that the material will enter the inside of the tip of the second gate 35, and the slide core 33 can be smoothly moved. Thus, in the present embodiment in which the second gate 35 is formed by a simple operation of moving the slide core 33 in the predetermined direction X, for example, the second gate is formed using a valve gate or a plurality of slide cores. Compared with the case where it does, remarkably simplification of a structure is achieved.

  Next, as shown in FIG. 7C, a secondary thermoplastic material is injected into the second cavity K2 through the second gate 35 to form the additional layer 20b (second step). As a result, the surface wall 23 of a predetermined cylindrical girder part (corner girder part 14A and intermediate girder part 14B) has a two-layer cross-sectional structure. After this second step, the mold is opened by moving the movable mold 32 and the slide core 33 through a conventionally known pressure holding process and cooling process, and an upper pallet 10a (lower pallet 10b) which is an injection molded product. Take out.

Next, a method for welding the pallets 10a and 10b will be described.
Now, as shown in FIG. 6, the upper pallet 10a and the lower pallet 10b formed as described above are connected by thermally welding the end faces of the respective cylindrical girders 14A, 14B, and 14C. When connecting these pallets 10a and 10b, first, as shown in FIG. 8 (a), the end faces of the cylindrical beam portions 14 of the pallets 10a and 10b are opposed to each other.

  Next, as shown in FIG. 8B, in a state where the pallets 10a and 10b are positioned, a hot platen 37 is inserted between the cylindrical beams 14 of the pallets 10a and 10b. And the end surface of each cylindrical girder part 14 is melted by heating by the hot platen 37. In that case, as shown in FIG.8 (c), the end surface of each cylindrical girder part 14 elutes toward the side (left-right direction in the same figure).

  Here, in the present embodiment, the end face 28 in the surface wall 23 (part having a two-layer cross section) of the corner beam part 14A and the intermediate beam part 14B constituting the part exposed to the outside (the peripheral wall 20 of the pallet 10) is provided. It consists only of the additional layer 20b. In other words, the end face T of the base material layer 20a (the lower end face in the upper pallet 10a and the upper end face in the lower pallet 10b) is covered with the additional layer 20b over the entire surface. Therefore, in the present embodiment, for example, the end of the base material layer 20a is compared with the case where the end surface 28 of the surface wall 23 (part having a two-layer structure) is configured by both the additional layer 20b and the base material layer 20a. The amount of heat applied to the part is reduced. Thereby, reduction of the elution amount of the base material layer 20a is achieved.

  Next, as shown in FIG.8 (d), the cylindrical beam parts 14 of both pallets 10a and 10b are connected in the state which the welding part of each cylindrical beam part 14 was fuse | melted. At this time, even if the welded portions of the cylindrical spar 14 are pressed together with a considerable pressing force, the elution amount of the base material layer 20a toward the additional layer 20b is reduced, so that the elution portion of the base material layer 20a Is stopped inside the additional layer 20b. Therefore, the melted portion of the base material layer 20a does not elute on the surface of the additional layer 20b. Thereafter, as shown in FIG. 8 (e), the beat 41 eluted to the outside of the additional layer 20b in the predetermined cylindrical girders 14A and 14B is removed by a beat remover with a claw. Incidentally, the beat 42 protruding inward from the base material layer 20a on the surface wall 23 (part having a two-layer cross section) of each of the cylindrical girders 14A and 14B is not visible from the outside, and therefore needs to be removed. There is no. As a result, the base material layer 20a does not elute to the outside, and the pallet 10 having a flat and good appearance is obtained in which the entire peripheral wall 20 is constituted only by the additional layer 20b.

The effects exhibited by the above embodiment will be described below.
The pallet 10 is configured by welding the cylindrical beam portions 14 of the pair of upper and lower pallets 10a and 10b. In the pallet 10a (10b), the end face 28 of the surface wall 23 (part having a two-layer cross section) of the corner beam part 14A and the intermediate beam part 14B constituting the part exposed to the outside is constituted only by the additional layer 20b. Has been. Therefore, in this embodiment, the amount of heat applied to the end of the base material layer 20a is reduced, and the amount of elution of the base material layer 20a can be reduced. Thereby, even if the welded portions of the cylindrical girders 14 of the pallets 10a and 10b are pressed with a considerable pressing force, the molten portion of the base material layer 20a does not elute on the surface of the additional layer 20b. It is possible to obtain a pallet 10 with good appearance that is unified by the color tone or material of the additional layer 20b.

  Moreover, it is preferable that the end surface of each cylindrical beam part 14A, 14B, 14C in the upper pallet 10a (lower pallet 10b) is located on the same plane P. According to this, when the end faces of the cylindrical girders 14A, 14B, and 14C are welded to each other, welding by surface contact is possible over all of the cylindrical girders 14A, 14B, and 14C, and the welding area of both is sufficiently secured. The As a result, compared to the conventional pallet in which a gap is formed between the end faces of the cylindrical spar, the pallet of this embodiment has sufficient impact resistance and strength in the welded cylindrical spar 14A, 14B, 14C. It becomes easy to ensure.

  In each surface wall 23 of the corner beam portion 14A and the intermediate beam portion 14B (part having a two-layer structure), the cross-sectional area of the base material layer 20a is reduced toward the tip (end surface 28 on the welded portion side). ing. According to this, the amount of heat applied to the end portion of the base material layer 20a is further reduced, and the elution amount of the base material layer 20a can be further reduced. As a result, the problem that the melted portion of the base material layer 20a is eluted on the surface of the additional layer 20b can be avoided more effectively.

  In the step of injecting the primary thermoplastic material into the first cavity K1 when forming the part (surface wall 23 of the corner beam part 14A and the intermediate beam part 14B) having a two-layer structure in the pallets 10a and 10b. The tip of the second gate 35 is sealed by the movable mold 32. Therefore, there is no possibility that the primary thermoplastic material will enter the tip of the second gate 35, and the slide core 33 can be moved smoothly.

  The peripheral wall 20 is configured to have a two-layer structure of the base material layer 20a and the additional layer 20b, and the base material layer 20a and the additional layer 20b are formed to have different colors. Since the base material layer 20a and the additional layer 20b are different in color, it is easy to distinguish between the peripheral wall 20 and the inner region of the fork insertion hole 21. Therefore, it is possible to prevent the fork from accidentally hitting the peripheral wall 20 and to insert the fork into the fork insertion hole 21 more reliably.

  The base material layer 20a is made of a recycled resin synthetic resin, the additional layer 20b is made of a virgin synthetic resin, and the additional layer 20b is disposed outside the base material layer 20a. Since the additional layer 20b is made of a synthetic resin of virgin material, the coloring effect is more easily exhibited than the base material layer 20a, and the presence of the peripheral wall 20 or the presence of the fork insertion hole 21 can be easily distinguished. To. Further, the impact resistance of the peripheral wall 20 is enhanced by configuring the additional layer 20b with a synthetic resin of a virgin material that is stronger than a synthetic resin of a recycled material.

  -The pallet 10 as a whole is made of recycled synthetic resin, and the additional layer 20b is only provided on the peripheral wall 20. Therefore, the effect of the present invention can be obtained while suppressing the manufacturing cost of the pallet 1 at a lower cost.

In addition, this embodiment can also be changed and embodied as follows.
-As long as the pallets 10a and 10b are sufficiently welded, the heights of the cylindrical girders 14A, 14B, and 14C may not be the same.

  In the upper pallet 10a (lower pallet 10b), the base material layer 20a may be included in the welded portion side end surfaces 28 of the surface walls 23 (two-layer cross-section structure) of both the corner beams 14A and the intermediate beams 14B.

-As shown in FIG. 9, you may employ | adopt the structure by which only a part of end surface T of the base material layer 20a was coat | covered with the additional layer 20b.
If the elution of the base material layer 20a on the surface of the additional layer 20b is suppressed, for example, the base material layer 20a whose cross-sectional area is constant or expands toward the tip (welded portion side end face 28) is employed. May be. Here, the “cross section” means a cross section parallel to the upper plate member 11 (lower plate member 12).

  As shown in FIG. 10 (a), the lower end portion of the peripheral wall of the upper pallet 10a and the upper end portion of the peripheral wall of the lower pallet 10b may each have a two-layer cross-sectional structure along the longitudinal direction N. Further, for example, as shown in FIG. 10B, a cross-sectional two-layer structure may be partially formed along the short edge of the fork insertion hole 21. In these cases, the peripheral wall 20 of the pallet 10 is formed only from the base material layer 20a except for a portion having a two-layer structure in cross section.

  -The shape of the molded product is not particularly limited, and may be either vertically long or horizontally long. And regarding welding of a molded product, any of welding of vertically long molded products, welding of horizontally long molded products, and welding of vertically long molded products and horizontally long molded products may be used. .

  In this embodiment, first, a pair of molded members (upper pallet 10a) in which the plate-like material 11 (12) and the cylindrical beam portion 14 are integrated is molded, and then the pair of molded members are welded together. Although the pallet 10 was manufactured by the method, the manufacturing method of the pallet 10 is not limited to this. That is, the shape of the molded members welded to each other is not limited to this. Other examples of this type of production method include the following. For example, the welded portion of one molded member is molded with the base material layer 20a and the additional layer 20b, the additional layer 20b is provided on the end surface 28 of the base material layer 20a, and the welded portion of the other molded member is replaced with the additional layer 20b. Even if these two molded members are molded by molding only with the material to be formed, the base material layer 20a of one molded member does not elute on the surface of the additional layer 20b of the other molded member. There is no loss.

  The base material layer 20a may be composed of a synthetic resin of virgin material and the additional layer 20b may be made of a synthetic resin of recycled material so that the color tone may be different. Both the base material layer 20a and the additional layer 20b may be synthetic resin of recycled material. Or you may make it comprise with the same material of the synthetic resin of a virgin material, and you may make it a color tone differ. Further, the additional layer 20b may be made of a material (for example, an elastomer) completely different from the base material layer 20a.

  The base material layer 20a and the additional layer 20b may be formed of a material having predetermined physical properties such as impact resistance and conductivity. In this case, even if the thickness of the additional layer 20b is made thinner than that of the base material layer 20a, the base material layer 20a is eluted on the surface of the additional layer 20b when welding one molding member and the other molding member. Therefore, the physical properties of the additional layer 20b can be fully exhibited.

  As long as the materials forming the base material layer 20a and the additional layer 20b are different, the base material layer 20a and the additional layer 20b may have the same color tone. For example, when the base material layer 20a is formed from a recycled material and the additional layer 20b is formed from a conductive material, the color tone of both is black.

-It is good also as a structure of two or more cross-sections by making the additional layer 20b into multiple layers.
A coloring material may be put in the base material layer 20a so that the color of the inner wall of the peripheral wall 20 of the pallet 10 and the fork insertion hole 21 may be different.

-You may form the inclination wall 25 of the beam parts 14A and 14B in a cross-sectional double layer structure. Further, the back wall 24 may be formed in a two-layer structure in cross section.
Further, the technical idea that can be grasped from the embodiment will be described below.

  The method for welding molded products, wherein an end face of the welded portion forming the plurality of cross-sectional layers is formed of only the additional layer. According to this, the elution amount of the base material layer is further reduced, and the problem that the melted portion of the base material layer is eluted on the surface of the additional layer can be avoided more effectively.

  The method for welding molded products, wherein the base material layer has a cross-sectional area that is reduced toward the end face of the welded portion. According to this, the elution amount of the base material layer is further reduced, and the problem that the melted portion of the base material layer is eluted on the surface of the additional layer can be avoided more effectively.

A molded product characterized in that the base material layer is not exposed on the surface of the additional layer. According to this, a good-looking molded product can be obtained.
A first step of forming a base material layer by injecting a primary thermoplastic material through a first gate into a first cavity formed by a stationary mold and a slide core independent of the movable mold; and the slide core Is injected into the second cavity formed by moving the base plate away from the base material layer through the second gate provided in the fixed mold and the slide core, and the additional layer is injected. And a second step of molding the molded product, wherein a tip of the second gate is sealed by the movable mold during the first step. According to this, there is no possibility that the primary thermoplastic material injected into the first cavity is adsorbed around the tip of the second gate, and the slide core can be moved easily and quickly.

The side view which shows the pallet of this embodiment. A side sectional view showing the pallet. The bottom view which shows an upper pallet. AA line sectional view in FIG. BB sectional drawing in FIG. The sectional side view which shows the state at the time of welding an upper pallet and a lower pallet. (A)-(c) is explanatory drawing which shows the shaping | molding method of an upper pallet. (A)-(e) is a partial expanded sectional view which shows the state at the time of welding an upper pallet and a lower pallet. The partial expanded sectional view showing the surface wall of another example. (A) And (b) is a side view which shows the pallet of another example. The side view which shows the conventional pallet. 12 is a sectional view taken along line 12-12 in FIG. The partial expanded sectional view which shows the cylindrical girder part of the pallet. The partial expanded sectional view which shows the state at the time of welding the cylindrical girder parts in the pallet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Upper plate-shaped material, 12 ... Lower plate-shaped material, 14 ... Cylindrical girder part, 14A ... Corner girder part, 14B ... Intermediate girder part, 14C ... Central girder part, 20a ... Base material layer, 20b ... Additional layer, 28: A welded portion side end surface as an end surface.

Claims (4)

In the welding method of the molded product in which both molding members are connected by welding the end faces of the welded portions of the pair of molding members arranged opposite to each other,
Heating and melting end faces of the welded portions of the pair of molded members;
And having the end faces of the welded portions face each other and connecting them while pressing to integrate the pair of molded members,
As at least one molded member of the pair of molded members,
At least a portion of the welding portion comprises a base material layer made of the base material, a cross-section a plurality of layers of at least the color tone or a different additional layer of material from the uterine material layer while being applied to the surface side of the uterine material layer such to, cross plurality layer portion of the welded portion is formed such that the base material layer toward the end portion side is reduced, the additional layer from the surface side to the end face of the welded portion in a cross-section multiple layer portion A method of welding a molded product, characterized by using a molded member that is formed . A pair of pallet members having a plate-like material and a plurality of cylindrical girder portions extending from the plate-like material are arranged with the cylindrical girder portion facing each other, and the welded portion of the tubular girder portion is arranged . In the welding method of the pallet in which both pallet members are connected by welding the end faces ,
Heating and melting the end surfaces of the welded portions of the pair of pallet members,
A process of integrating the pair of pallet members by causing the end faces of the welded portions to face each other and pressing them together.
As the pallet member,
At least a portion of the welded portion of the tubular girder portion, and the base material layer made of the base material, the uterine material layer while being applied to the surface side of the uterine material layer and at least shade, or different additional layers of material name a sectional multiple layers, welding method of the pallet, which comprises using a pallet member only part of the surface side of the end face of the welded portion in a cross-section multiple layer portion is covered from the front side by the additional layer . A pair of pallet members having a plate-like material and a plurality of cylindrical girder portions extending from the plate-like material are arranged with the cylindrical girder portion facing each other, and the welded portion of the tubular girder portion is arranged . In the welding method of the pallet in which both pallet members are connected by welding the end faces ,
Heating and melting the end surfaces of the welded portions of the pair of pallet members,
A process of integrating the pair of pallet members by causing the end faces of the welded portions to face each other and pressing them together.
As the pallet member,
At least a portion of the welded portion of the tubular girder portion, and the base material layer made of the base material, the uterine material layer while being applied to the surface side of the uterine material layer and at least shade, or different additional layers of material it name a sectional multiple layers, with the end face of the welded portion in a cross-section multiple layers portion is formed from said additional layer and the base material layer, the end face of the additional layer to the end face of the base material layer protrudes A method for welding pallets, characterized by comprising: A pair of pallet members having a plate-like material and a plurality of cylindrical girder portions extending from the plate-like material are arranged with the cylindrical girder portion facing each other, and the welded portion of the tubular girder portion is arranged . In the welding method of the pallet in which both pallet members are connected by welding the end faces ,
Heating and melting the end surfaces of the welded portions of the pair of pallet members,
A process of integrating the pair of pallet members by causing the end faces of the welded portions to face each other and pressing them together.
As the pallet member,
A pallet member molded by two-color molding, a part of the welded portion of the tubular girder portion, and the base material layer consisting of base material with the recess is formed on the surface side, wherein the uterine material layer It Na sectional plurality of layers of different additional layers of color tone and uterine material layer while being added to the recesses, the base material layer in a cross-section multiple layer portion is the base material layer in other parts of the tubular girder A pallet welding method characterized by using a pallet member formed thinner than the pallet member, wherein the additional layer is formed on the end face of the welded portion in the cross-sectional multi-layer part from the surface side .

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