A manufacturing process and equipment for molded plastic pallets

Abstract

This invention discloses a production process and equipment for one-time molding of plastic pallets. It includes steps such as an upper support feeding an upper sheet into the upper mold of a die and vacuum forming multiple feet within the upper mold; a lower support feeding a lower sheet into the upper mold of a die; the upper and lower sheets being bonded together; and a hydraulic press heat-sealing the sheet product. Because this invention plasticizes the raw material through two extruder screws and extrudes two sheets (upper and lower) through dies, first vacuum forming multiple feet on the upper sheet, and then bonding the upper and lower sheets together through the upper and lower molds, and finally heat-sealing the sheet product with a hydraulic press, a plastic pallet with feet is formed in one step, resulting in high production efficiency.

Description

Technical Field

[0001] This invention relates to a plastic molding process and equipment, and more particularly to a one-piece molded plastic pallet production process and equipment. Background Technology

[0002] In the logistics industry, plastic pallets are widely used for material handling. However, conventional plastic pallets often employ a double-layer thermoforming process involving secondary heating, or their feet are mechanically attached to the chassis. This not only increases production costs but also adds an extra step to the assembly process, making the process more complex. Summary of the Invention

[0003] One object of the present invention is to provide a production process and equipment for one-piece molded plastic pallets with high production efficiency.

[0004] Another objective of this invention is to provide a highly automated production equipment for one-piece molded plastic pallets.

[0005] To achieve the above objectives, the technical solution of the present invention is:

[0006] This invention is a production process for a one-time molding plastic pallet, which includes the following steps: (1) Plastic raw materials are plasticized by the screws of two extruders and extruded into upper and lower sheets through the die; (2) The upper and lower sheets are laid flat on the upper and lower brackets (i.e., the left and right brackets in the figure) with heat insulation; (3) The upper bracket sends the upper sheet into the upper mold of the mold and vacuum-forms multiple feet in the upper mold; (4) The lower bracket sends the lower sheet into the lower mold; the upper and lower brackets are removed from the mold frame; (5) The upper and lower molds of the mold are closed, and the upper and lower sheets are attached together. The sheet products are heat-sealed by a hydraulic press; (6) Compressed air is blown into the mold cavity to make the upper and lower sheets adhere tightly to the mold with cooling function; (7) When the molding time is reached, the compressed air is discharged, the mold is opened, and the product is taken out; (8) After the product is taken out, the product is completed through inspection, trimming, shaping and other processes.

[0007] This invention relates to a production equipment for one-piece molded plastic pallets. It includes two extruders, a left guide rail, a right guide rail, a frame, a frame fixture, an upper support, a lower support, an upper die, and a lower die. The frame fixture, upper die, and lower die are installed inside the frame from top to bottom, with the upper and lower dies facing each other. The left and right guide rails are located on opposite sides of the frame. The upper and lower supports slide on the left and right guide rails and can slide along the left and right guide rails between the upper and lower dies of the frame. The two extruders are located outside the left and right guide rails, with their dies facing the upper and lower supports, respectively.

[0008] The upper support includes an upper base, an upper outer frame, multiple upper lifting cylinders, two clamping rods, two sets of clamping cylinders, a clamping frame, multiple lower lifting cylinders, a panel, and an upper top frame. The upper top frame is serrated and located around the outer perimeter of the upper outer frame. The bottom of the upper outer frame has a sliding groove that mates with the left guide rail. The cylinder bodies of the multiple upper lifting cylinders are fixed to the upper outer frame, and the piston rods of the multiple upper lifting cylinders have upward-facing ends that connect to the bottom of the upper top frame to lift the sheet material upwards. The cylinder bodies of the multiple sets of clamping cylinders are symmetrically fixed to the outer side of the clamping frame. The piston rods of the multiple sets of clamping cylinders pass through the clamping frame, and the ends of the piston rods are connected to the outer ends of the four clamping rods, the inner ends of the clamping rods being serrated. The cylinder bodies of the multiple lower lifting cylinders are fixed to the upper outer frame, and the piston rod ends of the multiple lower lifting cylinders are downward-facing and connected to the upper base. The panel is fixedly installed on the top surface of the upper outer frame.

[0009] The lower support includes a lower base, a lower outer frame, and multiple top-feed cylinders; the bottom of the lower base is provided with a sliding groove that mates with the right guide rail; the cylinder bodies of the multiple top-feed cylinders are fixed on the lower base; the piston rods of the multiple top-feed cylinders have their rod ends facing upwards and connected to the bottom of the lower outer frame; the upper top frame of the lower outer frame is serrated so that the serrated inner end of the clamping rod can be inserted.

[0010] The frame fixture includes a fixed frame, multiple clamping rods, and multiple sets of frame clamping cylinders; the fixed frame is installed on the frame; the cylinder bodies of the multiple sets of frame clamping cylinders are symmetrically fixed on the outer side of the fixed frame, and the piston rod ends of the multiple sets of frame clamping cylinders are respectively connected to the outer ends of the multiple clamping rods, and the inner ends of the clamping rods are serrated.

[0011] After adopting the above solution, since the plastic raw material is plasticized by the screws of two extruders and extruded into two sheets, upper and lower, by the die, multiple feet are first vacuum-formed on the upper sheet, and then the upper and lower molds are closed to make the upper and lower sheets stick together. The sheet products are then heat-sealed by a hydraulic press to form a plastic pallet with feet in one go, resulting in high production efficiency.

[0012] The plastic pallet production equipment designed in this invention adopts two extruders, a left guide rail, a right guide rail, a frame, a frame fixture, an upper bracket, a lower bracket, an upper mold, and a lower mold. The upper bracket and the lower bracket are slidably connected to the left guide rail and the right guide rail respectively, and can slide along the left guide rail and the right guide rail between the upper mold and the lower mold of the frame, thereby feeding the upper and lower sheets in the upper bracket and the lower bracket into the mold, completing the vacuum forming of the foot block and the heat sealing of the upper and lower sheets, with a high degree of automation.

[0013] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0014] Figure 1 This is an isometric view of the present invention;

[0015] Figure 2 This is an isometric view of the bracket of the present invention;

[0016] Figure 3 This is an isometric view of the bracket clamp of the present invention;

[0017] Figure 4 This is a schematic diagram of the installation of the upper bracket and the upper cylinder of the present invention;

[0018] Figure 5 This is another structural diagram of the bracket panel of the present invention;

[0019] Figure 6 This is a top-view axonometric drawing of the lower bracket of the present invention;

[0020] Figure 7 This is a bottom-view axonometric drawing of the lower bracket of the present invention;

[0021] Figure 8 This is an isometric view of the frame fixture of the present invention. Detailed Implementation

[0022] I. Process

[0023] like Figure 1 As shown, the present invention is a production process for a one-time molding plastic pallet, which includes the following steps: (1) Plastic raw materials are plasticized by two extruders 1 screws and extruded into upper and lower sheets through the die respectively; (2) The upper and lower sheets are laid flat on the upper support 6 and lower support 7 with heat insulation; (3) The upper support 6 sends the upper sheet into the upper mold 8 of the mold and vacuum-forms multiple foot blocks in the upper mold 8; (4) The lower support 7 sends the lower sheet into the lower mold 9; the upper and lower supports are removed from the frame; (5) The upper mold 8 and lower mold 9 of the mold are closed, the upper sheet and the lower sheet are attached together, and the sheet product is heat-sealed by a hydraulic press; (6) Compressed air is blown into the mold cavity to make the upper sheet and the lower sheet adhere tightly to the mold with cooling function for molding; (7) When the molding time is reached, the compressed air is discharged, the mold is opened, and the product is taken out; (8) After the product is taken out, the product is completed by inspection, trimming, shaping and other processes.

[0024] II. Equipment

[0025] like Figure 1 As shown, the present invention is a production equipment for one-time molding of plastic pallets, which includes two extruders 1, left guide rail 2, right guide rail 3, frame 4, frame clamp 5, upper bracket 6, lower bracket 7, upper mold 8, and lower mold 9.

[0026] The frame fixture 5, upper die 8, and lower die 9 are installed from top to bottom inside the frame 4. The upper die 8 and lower die 9 are opposite each other and can be closed by the drive of the hydraulic press worktable. The left guide rail 2 and right guide rail 3 are located on both sides of the frame 4. The upper bracket 6 and lower bracket 7 are slidably connected to the left guide rail 2 and right guide rail 3 respectively and can slide along the left guide rail 2 and right guide rail 3 between the upper die 8 and lower die 9 of the frame 4. The two extruders 1 are located outside the left guide rail 2 and right guide rail 3 respectively, and the dies of the two extruders 1 face the upper bracket 6 and lower bracket 7 respectively, so as to spread the plasticized plastic on the upper bracket 6 and lower bracket 7.

[0027] like Figure 2 — Figure 4 As shown, the upper bracket 6 includes an upper base 61, an upper outer frame 62, multiple lower top cylinders 63, four clamping rods 64, four sets of clamping cylinders 65, a clamping frame 66, multiple upper top cylinders 67, a panel 68, and an upper top frame 621.

[0028] The upper top frame 621 is serrated and located around the upper outer frame 62. The bottom of the upper outer frame 62 is provided with a sliding groove that mates with the left guide rail 2 (not shown in the figure). The cylinder bodies of multiple upper top cylinders 67 are fixed on the upper outer frame 62. The piston rods of the multiple upper top cylinders 67 have their rod ends facing upward and connected to the bottom of the upper top frame 621 to lift the sheet material upward. The cylinder bodies of the four sets of clamping cylinders 65 are symmetrically fixed on the outer side of the clamping frame 66. The piston rods of the four sets of clamping cylinders 65 pass through the clamping frame 66 and their rod ends are respectively connected to the outer ends of the four clamping rods 64. The inner ends of the clamping rods 64 are serrated.

[0029] The cylinder bodies of the multiple lower-push cylinders 63 are fixed on the upper outer frame 62, and the rod ends of the piston rods of the multiple lower-push cylinders 63 are connected downward to the upper base 61, so that the upper base 61 and the clamping frame 66 move downward together.

[0030] The panel 68 is fixedly installed on the top surface of the upper outer frame 62, and its surface has two forms, one of which is as follows: Figure 2 The planar shape shown, another type as... Figure 5 The panel 68' shown has multiple upward-protruding feet 681', and molten sheet material can be directly laid flat on this panel 68', making the material used in the formed tray more uniform.

[0031] like Figure 6 , Figure 7As shown, the lower support 7 includes a lower base 71, a lower outer frame 72, and multiple top-feeding cylinders 73. The bottom of the lower base 71 is provided with a sliding groove 711 that mates with the right guide rail 3. The cylinder bodies of the multiple top-feeding cylinders 73 are fixed on the lower base 71. The piston rods of the multiple top-feeding cylinders 73 have their rod ends pointing upwards and are connected to the bottom of the serrated outer edge of the lower outer frame 72. The outer edge of the lower outer frame 72 is serrated so that the serrated inner end of the clamping rod 64 can be inserted to clamp the lower sheet.

[0032] like Figure 8 As shown, the frame clamp 5 includes a fixed frame 51, four clamping rods 52, and four sets of frame clamping cylinders 53. The fixed frame 51 is mounted on the frame 4; the cylinder bodies of the four sets of frame clamping cylinders 53 are symmetrically fixed to the four sides of the fixed frame 51, and the piston rod ends of the four sets of frame clamping cylinders 53 are respectively connected to the outer ends of the four clamping rods 52. The inner ends of the clamping rods 52 are serrated so as to pass through the serrated upper top frame 621 of the upper bracket 6.

[0033] Working principle of the invention:

[0034] like Figure 2 , Figure 6 As shown, firstly, the upper bracket 6 and the lower bracket 7 enter the mold area simultaneously. The upper cylinder 67 of the upper bracket 6 pushes the upper frame 621 upward, so that the four sides of the upper sheet enter the machine frame fixture 5 in the mold area. The four sets of machine frame clamping cylinders 53 of the machine frame fixture 5 move inward, driving the four clamping rods 52 to move inward. The serrated clamping rods 52 pass through the serrated upper frame 621 of the upper outer frame 62 of the upper bracket 6 and clamp the upper sheet. The upper cylinder 67 of the upper bracket 6 retracts the serrated upper frame 621 of the upper outer frame 62 of the bracket downward. Simultaneously, the ejector cylinder 73 of the lower support 7 pushes the serrated frame of the lower outer frame 72 upward, causing the four edges of the lower sheet to enter the four clamping rods 64 of the upper support 6. The four sets of clamping cylinders 65 of the upper support 6 move inward, driving the four clamping rods 64 to move inward. The serrated clamping rods 64 pass through the serrated outer edge of the lower outer frame 72 of the lower support 7 and clamp the lower sheet. The ejector cylinder 73 of the lower support 7 retracts the lower outer frame 72 downward. The lower support 7 exits the mold area to the right, and the lower ejector cylinder 63 of the upper support 6 pushes the clamp downward, placing the lower sheet into the lower mold 9. The lower ejector cylinder 63 of the upper support 6 retracts the four clamping rods 64. The upper support 6 exits the mold area to the left, and the frame clamp 5 at the top of the mold area places the upper sheet into the upper mold under the action of the cylinder.

[0035] The key point of this invention is that multiple foot blocks are vacuum-formed in the upper mold.

[0036] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent application and the contents of the specification of the present invention should still fall within the scope of the patent of the present invention.

Claims

1. A manufacturing process for a one-piece molded plastic pallet, characterized in that: It includes the following steps: (1) Plastic raw materials are plasticized by the screws of two extruders and extruded into upper and lower sheets through the die; (2) The upper and lower sheets are laid flat on the upper and lower brackets with heat insulation; (3) The upper bracket sends the upper sheet into the upper mold and vacuum-forms multiple feet in the upper mold; (4) The lower bracket sends the lower sheet into the mold of the lower mold. (5) The upper and lower molds of the mold are closed, and the upper and lower sheets are attached together. The sheet product is heat-sealed by the hydraulic press; (6) Compressed air is blown into the mold cavity to make the upper and lower sheets adhere tightly to the mold with cooling function; (7) When the molding time is reached, the compressed air is discharged, the mold is opened, and the product is taken out; (8) After the product is taken out, it is inspected, trimmed, and shaped to complete the product production.

2. The production equipment for one-piece molded plastic pallets according to claim 1, characterized in that: It includes two extruders, a left guide rail, a right guide rail, a frame, a frame fixture, an upper bracket, a lower bracket, an upper die, and a lower die; the frame fixture, the upper die, and the lower die are installed inside the frame from top to bottom, with the upper and lower dies facing each other; the left and right guide rails are located on both sides of the frame, and the upper and lower brackets slide on the left and right guide rails respectively and can slide along the left and right guide rails between the upper and lower dies of the frame; the two extruders are located outside the left and right guide rails respectively, and the dies of the extruders face the upper bracket and the lower bracket respectively.

3. The production equipment for one-piece molded plastic pallets according to claim 2, characterized in that: The upper support includes an upper base, an upper outer frame, multiple upper lifting cylinders, four clamping rods, four sets of clamping cylinders, a clamping frame, multiple lower lifting cylinders, a panel, and an upper top frame. The upper top frame is serrated and located around the outer perimeter of the upper outer frame. The bottom of the upper outer frame has a sliding groove that mates with the left guide rail. The cylinder bodies of the multiple upper lifting cylinders are fixed to the upper outer frame, and the piston rods of the multiple upper lifting cylinders have upward-facing ends that connect to the bottom of the upper top frame to lift the sheet material upwards. The cylinder bodies of the four sets of clamping cylinders are symmetrically fixed to the outer side of the clamping frame. The piston rods of the four sets of clamping cylinders pass through the clamping frame, and the ends of the piston rods are connected to the outer ends of the four clamping rods, with the inner ends of the clamping rods being serrated. The cylinder bodies of the multiple lower lifting cylinders are fixed to the upper outer frame, and the piston rod ends of the multiple lower lifting cylinders are downward-facing and connected to the upper base. The panel is fixedly installed on the top surface of the upper outer frame.

4. The production equipment for one-piece molded plastic pallets according to claim 2, characterized in that: The lower support includes a lower base, a lower outer frame, and multiple top-feed cylinders; the bottom of the lower base is provided with a sliding groove that mates with the right guide rail; the cylinder bodies of the multiple top-feed cylinders are fixed on the lower base; the piston rods of the multiple top-feed cylinders have their rod ends facing upward and connected to the bottom of the lower outer frame; the outer edge of the lower outer frame is serrated so that the serrated inner end of the clamping rod can be inserted.

5. The production equipment for one-piece molded plastic pallets according to claim 2, characterized in that: The frame fixture includes a fixed frame, multiple clamping rods, and multiple sets of frame clamping cylinders; the fixed frame is installed on the frame; the cylinder bodies of the multiple sets of frame clamping cylinders are symmetrically fixed on the outer side of the fixed frame, and the piston rod ends of the multiple sets of frame clamping cylinders are respectively connected to the outer ends of the multiple clamping rods, and the inner ends of the clamping rods are serrated.

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