A roll molded member reinforced with built-in bone material

Abstract

This invention proposes a rotationally molded component with built-in reinforcement, belonging to the field of rotational molding component manufacturing technology. It solves the technical problem of powder leakage during the molding process of rotationally molded components with built-in reinforcement, which makes it difficult to simultaneously achieve uniform shell wall thickness and connection strength. This invention includes a rotationally molded, hollow shell with built-in reinforcement inside the shell cavity. Anchors are provided on the normal outer periphery of the built-in reinforcement, intersecting with the normal direction of the shell. The anchors have either a non-outwardly convex structure or an inwardly concave structure, forming an anchoring surface facing the inner end of the anchor for normal anchoring of the shell. The anchors also have a first transverse through-hole for conducting the shell on both sides of the built-in reinforcement, thereby enhancing the connection strength between the shells on both sides of the built-in reinforcement. This invention can be widely applied to the high-efficiency, high-quality molding of large rotationally molded components and the effective connection between multiple rotationally molded components.

Description

Technical Field

[0001] This application belongs to the field of rotational molding component manufacturing technology, and more specifically, relates to a rotational molding component with built-in reinforcement. Background Technology

[0002] Rotational molding is a process in which plastic raw materials are melted, uniformly adhered, and cooled to form a mold through rotating heating. It has advantages such as seamless one-time molding, adaptability to complex irregular structures, and the ability to produce large hollow products. In addition, its excellent weather resistance has led to its widespread application in rotational molding of ships (hulls and cabin components of small recreational boats and workboats), liquid storage tanks, and outer shells of transportation facilities.

[0003] For rotationally molded products with high strength requirements, existing conventional reinforcement methods mostly rely on increasing the shell wall thickness or integrally molded convex / concave reinforcing ribs. Increasing the shell wall thickness results in high material costs and a significant increase in structural weight; while convex / concave reinforcing ribs can slightly improve stiffness, the reinforcement effect is limited. The above rotational molding technology has also been applied to small (usually no more than 12 meters in length) double-hulled vessels (such as the utility model patent with publication number CN215590942U), adding concave and convex keels to the outer hull and concave and convex ribs to the inner hull to increase hull rigidity. In addition, "kissing points" are added between the inner and outer hulls to improve the overall structural rigidity of the hull. However, these measures are difficult to meet the hull structural rigidity and strength requirements when dealing with larger vessels (such as those exceeding 20 meters in length). Furthermore, the "kissing point" structure is limited to situations where the distance between the inner and outer hulls is small (usually no more than 20 cm). When the cabin size is large (such as exceeding 100 cm), the kissing point structure will disrupt the functional shape of the hull. Furthermore, outward-protruding structures increase water resistance and energy consumption, while inward-protruding structures compromise the integrity of the compartments, affecting stacking and cleaning. To fundamentally improve structural strength, existing technologies are gradually shifting towards a pre-installed support frame inside the shell, but this approach still has significant drawbacks in terms of molding processes and the structural integrity of rotationally molded components.

[0004] Chinese patent CN105599195A discloses a method for manufacturing double-layer all-plastic ships using rotational molding, which improves the overall strength of the hull by pre-setting support members within the mold. This method uses screws to fix the support members. To ensure connection strength, large rotational molding products require thousands or even tens of thousands of screws densely arranged. After rotational molding, the holes left by the screws after removal must be individually sealed, leading to complex assembly and disassembly processes, significantly reduced production efficiency, and a substantial increase in manufacturing costs. Furthermore, this patent only limits the gap between the outer end of the support member and the mold to within the designed thickness range of the hull, resulting in an overly broad range. A large gap is detrimental to ensuring the connection strength between the internal support members and the hull, and can easily cause powder leakage between cavities, making it difficult to ensure the uniformity of the rotational molding component's wall thickness. A small gap avoids the aforementioned problems, but it can lead to insufficient wall thickness in the hull molding, causing the overall structural strength to fail to meet usage requirements. This makes the vessel highly susceptible to damage when subjected to wave torsional forces, endangering the lives of the crew.

[0005] Chinese patent application CN110744760A discloses a rotational molding reinforced support and a rotational molding product. The support base is fixed by embedding its two ends into the inner wall of the rotational molding shell, while the middle main body provides support, partitioning, and compartmentalization for the cavities. While this structure improves the connection between the support and the shell to some extent, its anchoring relies solely on partial covering at the base. This fails to effectively prevent powder from flowing between different chambers during rotational molding, leading to uncontrolled local thickness of the shell and unstable bonding strength at the support positions. Consequently, it is difficult to meet the requirements for structural uniformity and overall strength for large, long rotational molding products.

[0006] Therefore, existing rotomolded components with built-in skeletons are prone to powder leakage during the molding process, making it impossible to balance the uniformity of shell wall thickness and connection strength, resulting in poor molding quality and structural consistency. Summary of the Invention

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A rotomolded component with built-in reinforcement includes a rotomolded and hollow shell. An internal reinforcement is provided within the shell cavity. An anchor is provided on the normal outer periphery of the internal reinforcement, intersecting with the shell's normal direction. The anchor has a non-outwardly convex structure or an inwardly concave structure, forming an anchoring surface facing the inner end of the anchor for normal anchoring of the shell. The normal distance G from the anchoring surface to the outer surface of the shell is less than the shell wall thickness B. The anchor also has a first transverse through-hole. The normal distance F from the outer end of the first transverse through-hole to the outer surface of the shell is less than the shell wall thickness B, for conducting the shell on both sides of the internal reinforcement.

[0008] Preferably, the width W of the first transverse through slot is less than the shell wall thickness B; when the sidewall of the first transverse through slot is a non-parallel structure, its width W is the arithmetic mean of the maximum and minimum hole widths.

[0009] Preferably, the normal distance H from the inner end of the first transverse through slot to the outer surface of the shell is greater than the shell wall thickness B, and the longitudinal span L between two adjacent first transverse through slots is less than twice the slot width W, i.e., L < 2W.

[0010] Preferably, the normal distance C from the outer end of the anchor to the outer surface of the shell is less than D, the width W of the first transverse through slot is less than D, D is the diameter of the large particles generated by the small particle aggregation effect, D=2d*E, where d is the average diameter of the rotational molding powder, and E is the thickness of the anchor.

[0011] Preferably, a positioning cylinder is provided on the normal outer periphery of the built-in bone material. The positioning cylinder is barrel-shaped and has an opening at its normal outer end.

[0012] Preferably, the side wall of the positioning cylinder is provided with a second transverse through slot, and the opening is provided with a circumferential flange.

[0013] Preferably, the anchor includes a plurality of longitudinal groove anchors distributed along the longitudinal direction of the built-in rib. The cross-section of the longitudinal groove anchor is U-shaped, and the normal inner end is connected to the outer periphery of the built-in rib. The bottom of the longitudinal groove anchor is provided with a plurality of through holes with a circumscribed circle diameter smaller than the width of the groove bottom. The through holes are used to connect the anchor and the built-in rib.

[0014] Preferably, the anchor is an integral anchor and / or a split anchor. The integral anchor is directly formed on the outer periphery of the built-in rib body; the split anchor is a separately manufactured anchor fixedly connected to the normal outer periphery of the built-in rib.

[0015] Preferably, the outer periphery of the built-in skeleton is provided with a connecting component for connecting the outer structural component of the shell. The connecting component is rigidly connected to the built-in skeleton. The connecting component includes a stud or riveting stud that protrudes normally from the outer surface of the shell, or a nut whose outer end is flush with the outer surface of the shell.

[0016] Preferably, the rotationally molded component is provided with multiple rigid conduits that penetrate the shells on opposite sides for passing through connecting rods that connect other structural components.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes anchors with anchoring surfaces and first transverse through-holes on the outer periphery of the built-in skeleton to form an inverted mechanical interlocking structure. This allows the rotationally molded shell to tightly engage with the anchors, significantly improving tensile, shear, and torsional resistance, fundamentally solving the problem of easy detachment and separation between built-in skeletons of different materials and the shell. Simultaneously, the first transverse through-hole allows for appropriate connectivity between the mold cavities on both sides of the skeleton, enhancing the transverse connection strength of the shell at the built-in skeleton location. Furthermore, the normal distance G from the anchoring surface to the outer surface of the shell is limited to be less than the shell wall thickness B, ensuring full normal engagement between the anchoring surface and the shell, guaranteeing the anchoring effect between the built-in skeleton and the shell. The normal distance F from the outer end of the first transverse through-hole to the outer surface of the shell is limited to be less than the shell wall thickness B, allowing for connection between the shell on both sides of the built-in skeleton, enhancing the shell strength at the built-in skeleton location. Further, by limiting the size based on the powder aggregation effect, excessive cavity expansion is avoided, achieving a balance between uniform wall thickness and limiting powder cavity expansion, ensuring uniform powder distribution and controllable shell connectivity. Meanwhile, a variety of integrated and split anchors and positioning cylinders are available, which can be flexibly selected according to product specifications and processes. Combined with the corresponding positioning pins on the rotational molding mold that do not need to be disassembled, they have the advantages of low manufacturing cost, high connection strength, good structural stability and high production efficiency. In addition, through the setting of connecting parts and rigid conduits, external components can be docked and multi-unit segmented assembly can be realized, which is convenient for manufacturing ultra-large size and ultra-high strength rotational molding components. Overall, the structural reliability, molding accuracy and application scalability of rotational molding products are greatly improved.

[0018] The application forms of the rotomolded components of this invention can include any one of the following or other forms of rotomolded components: ships, double-walled containers, cargo containers, prefabricated houses, or ships. It is particularly suitable for reinforcing the hollow, closed inner cavity of double-walled rotomolded components, including double-walled containers, cargo containers, prefabricated houses, or ships. For double-walled barrel-shaped containers, there is an outer barrel wall and an inner barrel wall, with internal reinforcement between the inner and outer barrel walls. For ships with double hulls, the rotomolded hatch covers or separate decks are also independent rotomolded components. Specifically, for ships with single hulls and decks, their structure can also be reinforced by internal bulkheads, in which case the bulkhead plate is considered a type of internal reinforcement in a special structure. Therefore, for ships with single hulls and decks, the inner cavity of the rotomolded component is equivalent to the hull compartment; for rotomolded components with double hulls, the inner cavity refers to the compartment between the two hull layers. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the connection between a rotational molding component of the present invention and a rotational molding mold in one embodiment; Figure 2 for Figure 1 Enlarged view of point A; Figure 3 for Figure 1 A schematic diagram of the structure of the internal frame and the integrated tenon-and-mortise type anchor. Figure 4 A schematic diagram of one embodiment of the positioning cylinder; Figure 5 A schematic diagram of the structure of an integrated through-hole anchor. Figure 6 for Figure 5 The main view; Figure 7 For inclusion Figure 6 A schematic side sectional view of a rotationally molded component; Figure 8 A schematic diagram of the structure of an integrated, outwardly protruding, beveled-edge type anchor. Figure 9 for Figure 8 A cross-sectional view; Figure 10 This is a schematic diagram of the structure of a longitudinal groove anchor. Figure 11 A schematic diagram of the combination of an integrated through-hole anchor and a positioning cylinder; Figure 12 for Figure 11 A schematic diagram showing the alignment of the locating pins in the assembly and rotational molding mold; Figure 13 for Figure 12 A side sectional view; Figure 14 for Figure 12 AA sectional view; Figure 15 This is a schematic diagram showing the connection between the longitudinal groove anchor, the positioning cylinder assembly, and the built-in reinforcement. Figure 16 for Figure 15 Front sectional view; Figure 17 for Figure 16 Side sectional view; Figure 18 for Figure 16 Top view; Figure 19 This is a schematic diagram of the structure of one embodiment of the rotational molding component of the present invention; Figure 20 for Figure 19 Enlarged view of point B; Figure 21 for Figure 19Enlarged view of point C; Figure 22 This is a schematic diagram of the structure of one embodiment of the rotational molding component of the present invention; Figure 23 This is a schematic diagram of the structure of one embodiment of the rotational molding component of the present invention; Figure 24 for Figure 23 A schematic diagram showing the connection between the two rotationally molded components; Figure 25 for Figure 24 Enlarged view of point D.

[0021] Explanation of symbols in the diagram: 1. Shell; 2. Rotational molding mold; 3. Internal skeleton; 4. Anchor; 5. Anchoring surface; 6. First transverse through slot; 7. Stud; 8. Positioning cylinder; 9. Positioning pin; 10. Bottom hole; 11. Circumferential flange; 12. Outwardly protruding bevel; 13. Transverse flange; 14. Fixing hole; 15. First rotational molding component; 16. Second rotational molding component; 17. Third rotational molding component; 18. Connecting rod; 19. Guide tube; 20. Guardrail; 21. Flat keel; 22. Second transverse through slot. Detailed Implementation

[0022] To make the technical problems, solutions, and beneficial effects of this application clearer, the following detailed description of a rotomolded component with built-in reinforcement, in conjunction with the accompanying drawings and embodiments, is provided. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0023] It should be noted that the orientations described in this application are all defined based on the internal skeleton 3 (including the keel and ribs): the main body of the internal skeleton 3 is a plate-shaped web structure, wherein the transverse direction refers to the direction perpendicular to the surface of the web of the internal skeleton 3; the normal direction refers to the direction from the outer periphery of the web to the shell 1 and perpendicular to the inner wall of the shell 1; and the longitudinal direction is the extension direction of the internal skeleton 3 that is perpendicular to both the transverse and normal directions.

[0024] Example 1 Please see Figures 1-4 This invention provides a rotomolded component with built-in reinforcement, specifically a rotomolded ship with a double-layered hull reinforced with built-in reinforcement, including a rotomolded and hollow hull 1, with built-in reinforcement 3 (including keel and ribs) in the inner cavity of the hull 1, and anchors 4 that are intersecting and connected to the hull 1 in the normal direction on the outer periphery of the built-in reinforcement 3.

[0025] The normal cross connection here specifically refers to: the anchor is embedded into the shell 1 along the normal direction to form a stable normal cross fixation.

[0026] Anchor 4 has a non-outwardly convex or inwardly concave structure, forming an anchoring surface 5 facing the inner end of anchor 4 (the end closer to the built-in core 3), used for normal anchoring of the shell 1, which is the core of normal anchoring. This design utilizes the principle of mechanical limiting, and compared with conventional flat connection surfaces, it can form an inverted mechanical interlocking structure. During rotational molding, the molten plastic shell 1 completely wraps around anchor 4, and after cooling, it forms a tight interlock, effectively resisting normal separation force, fundamentally solving the problem of easy detachment between the built-in core 3 and the shell 1. Specifically, the anchoring surface 5 can adopt any adaptable structure such as a plane, inclined plane, or curved surface, as long as it can achieve normal limiting.

[0027] Anchor 4 is also provided with a first transverse through slot 6. The outer end of the first transverse through slot 6 is located within the shell wall thickness range. The normal distance from the outer end of the first transverse through slot 6 to the outer surface of the shell is less than the shell wall thickness, ensuring the conductivity effect. During rotational molding, the molten plastic can effectively connect the shells 1 on both sides of the built-in skeleton through the first transverse through slot 6, thereby enhancing the connection strength of the shells 1 at the built-in skeleton 3. At the same time, the shell 1 part is formed in the first transverse through slot 6 and on the side of the built-in skeleton 3, which works in conjunction with the inverted mechanical interlocking structure to doubly strengthen the connection reliability, improve the torsional and shear resistance of the anchor, and thus enhance the overall strength of the rotational molding component, adapting to the needs of large rotational molding products.

[0028] Furthermore, the anchor 4 is an integral anchor directly formed on the outer periphery of the inner bone material 3, specifically an integral tenon and mortise groove anchor, that is, multiple tenon and mortise structures are integrally formed on the outer periphery of the inner bone material 3, the anchoring surface 5 is the inverted bevel of the tenon and mortise structure, and the first transverse through slot 6 is a slot formed by adjacent tenon and mortise structures.

[0029] This integrated tenon-and-mortise groove anchor can be manufactured in one go through processes such as stamping, casting, and extrusion. It has both an anchoring surface 5 and a first transverse through-hole 6, eliminating the need for additional assembly processes, which greatly improves production efficiency and reduces manufacturing costs. At the same time, the structure of multiple continuous first transverse through-holes forms a dense inverted mechanical interlocking, and the anchoring surface 5 and the rotomolded shell 1 form an all-round interlocking, which can effectively resist normal pull-out force, shear force and alternating load, fundamentally solving the problem of easy detachment and separation between the built-in skeleton 3 and the shell 1. The overall connection strength is greatly improved compared with traditional single-point anchoring.

[0030] It should be noted that, in order to better limit powder leakage and ensure uniform wall thickness of the shell 1, the dimensional relationship between the anchor 4, the first transverse through slot 6, and the shell 1 is further defined. This dimensional limitation applies to the anchor 4 structure in various embodiments of this application. The aforementioned integrated tenon-and-mortise groove anchor will continue to be used as an example for further explanation.

[0031] The normal distance from the outer end of the anchor 4 to the outer surface of the shell 1 is defined as C, the normal distance from the anchoring surface 5 to the outer surface of the shell 1 is defined as G, and the normal distance from the outer end of the first transverse through-hole 6 to the outer surface of the shell 1 is defined as F. Specifically, when the anchoring surface 5 is not parallel to the outer surface of the shell 1, the distance G is the arithmetic mean of the maximum and minimum values. When the first transverse through-hole 6 is an open slot at the outer end, F = C; when the first transverse through-hole 6 is a closed hole at the outer end, and only the outer end of the first transverse through-hole 6 is used as the anchoring surface 5, F = G.

[0032] In this embodiment, the first transverse through-hole 6 of the integrated tenon-and-mortise type anchor is a groove, and its outer end is flush with the outer end of the anchor 4. At this time, F=C. Therefore, the normal distance G from the anchoring surface 5 to the outer surface of the shell 1 is less than the wall thickness B of the shell 1, so that the anchoring surface 5 and the shell 1 are fully engaged in the normal direction, ensuring the anchoring effect between the internal skeleton 3 and the shell 1. The normal distance C from the outer end of the integrated tenon-and-mortise type anchor to the outer surface of the shell 1 is less than the shell wall thickness B, and the normal distance F from the outer end of the first transverse through-hole 6 to the outer surface of the shell 1 is less than the shell wall thickness B, so as to conduct the shell 1 on both sides of the internal skeleton 3 and enhance the strength of the shell 1 at the internal skeleton 3.

[0033] Furthermore, the width W of the first transverse through-hole 6 is less than the thickness B of the shell 1. By limiting the opening width of the first transverse through-hole 6 in the transverse direction, the large-scale migration of rotational molding powder into the cavity is effectively suppressed, thereby ensuring uniform wall thickness and stable molding.

[0034] Since the anchoring surface 5 of the integrated tenon and mortise type anchor is an inverted inclined surface, its normal distance G is the distance from the midpoint of the inverted inclined surface to the outer surface of the shell 1. The first transverse through slot 6 is a non-vertical slot, and its width W is the arithmetic mean of the maximum and minimum hole widths of the first transverse through slot 6.

[0035] Furthermore, given that C is less than B, the shell wall thickness at the internal rib 3 becomes drastically thinner, weakening the shell strength. Therefore, the normal depth dimension of the first transverse through-hole 6 is further optimized: the normal distance H from the inner end of the first transverse through-hole 6 to the outer surface of the shell 1 is greater than the shell wall thickness B (C≤F≤G<B<H). This provides reinforcing ribs to the relatively thinner shell 1 at this location, further enhancing its strength. Simultaneously, even if H>B, the corner effect ensures that the inner side of the slot is completely covered by the shell 1, guaranteeing structural sealing and reliable molding.

[0036] Furthermore, the spacing between adjacent first transverse through slots 6 is optimized: the longitudinal span L of two adjacent first transverse through slots 6 is less than twice the slot width W, i.e., L < 2W, in order to further enhance the connection strength of the shell 1 at the built-in rib 3. It should be noted that L needs to be greater than W to ensure that independent slots can be formed, while controlling L to be less than 2W can, on the basis of ensuring molding feasibility, increase the degree of penetration of the shell 1 on both sides of the built-in rib 3 as much as possible, and further improve the overall connection strength of the shell 1 at the built-in rib 3.

[0037] Under the synergistic effect of H > B and L < 2W: on the one hand, the structural strength of the built-in rib 3 is supplemented by the larger slot depth H, and on the other hand, the shell 1 is continuously connected by the reasonable slot spacing L. Together, they avoid local stress concentration and structural weakness caused by improper slot arrangement or size, and further improve the overall strength and structural stability of the rotational molding component in the area of ​​the built-in rib 3.

[0038] Furthermore, in order to more accurately control the amount of powder crosslinking based on the physical aggregation characteristics of rotational molding powder, the above-mentioned dimensional relationships are further quantified and limited: the normal distance C from the outer end of the integrated tenon-and-mortise type anchor to the outer surface of the shell 1 is less than D, the width W of the first transverse through slot 6 is less than D, D is the diameter of the large particles generated by the small particle aggregation effect, D=2d*E, where d is the average diameter of the rotational molding powder, and E is the thickness of the anchor.

[0039] The above formula for calculating D is based on the mechanism of particle agglomeration and bridging effect during the flow of rotational molding powder. By coupling the average particle size d of the powder with the thickness E of the anchor, the critical size of powder bridging is quantitatively defined, making the limitation of the slot width more process-specific.

[0040] Further explanation using specific parameters: When B=10mm, d=0.3mm, and E=5mm, then D=2×0.3×5=3mm. W should be less than D, and C should also be less than D, while both C and D are less than B. When W≥D, in the initial stage of rotational molding, because the rotational molding powder is not fully melted, a large amount of rotational molding powder leaks into the side chamber through the first transverse through-hole 6. Furthermore, the consistency of the returned powder cannot be guaranteed, ultimately leading to uneven wall thickness of the shell 1. However, when W<D, the amount of powder leaking is significantly reduced due to the aggregation effect, thereby improving the uniformity of the shell 1's thickness.

[0041] Through the quantitative dimensional design based on the powder aggregation effect, the disordered flow of plastic powder into the cavity can be effectively suppressed from the molding mechanism, further ensuring the uniform and stable thickness of each part of the shell 1, and improving the overall molding quality and structural reliability of the rotational molding component.

[0042] In one embodiment, the built-in core 3 has multiple discretely distributed positioning cylinders 8 on its normal outer periphery. The positioning cylinders 8 are used to engage with positioning pins 9 provided on the rotational molding mold 2 to prevent the built-in core 3 from shifting due to the rotation of the rotational molding mold 2 and the disturbance of the molten plastic flow during the rotational molding process, thus ensuring the dimensional accuracy and structural stability of the rotationally molded component. The positioning cylinder is barrel-shaped, and its normal outer end has an opening, so that the outer end face of the positioning cylinder 8 abuts against the inner wall of the rotational molding mold 2. The positioning pins 9 suspend and limit the built-in core 3 in the preset installation position inside the rotational molding mold 2.

[0043] Furthermore, the side wall of the positioning cylinder 8 is provided with a second transverse through slot 22, and the outer end opening of the positioning cylinder 8 is provided with an inwardly curved circumferential flange 11. Preferably, the width W of the second transverse through slot 22 is less than D, and the circumferential flange 11 constitutes an anchoring surface. On the one hand, during the rotational molding process, the molten plastic can flow into the inner cavity of the positioning cylinder 8 through the second transverse slot 22, so that the shells 1 on both sides of the positioning cylinder are melted and connected as one, improving the bonding strength between the shell and the internal reinforcement; the end face of the circumferential flange 11 facing the inner end of the positioning cylinder constitutes an anchoring pressure-bearing surface, further strengthening the anchoring bonding effect between the positioning cylinder and the shell 1. On the other hand, the shell 1 covers the connection between the positioning cylinder 8 and the internal reinforcement 3 to form a sealed structure, so that after the mold is demolded, there is no need to perform a filling and repair process on the positioning cylinder position, which significantly improves the rotational molding production efficiency.

[0044] Furthermore, the positioning cylinder 8 can be an integral positioning cylinder or a separate positioning cylinder. The integral positioning cylinder is directly formed on the outer periphery of the built-in rib body 3; the separate positioning cylinder has a bottom hole 10 at the bottom end, which is used to connect the positioning cylinder 8 and the built-in rib 3.

[0045] In addition, a split positioning cylinder 8 is preferred. In this case, the positioning cylinder 8 can be formed by stamping stainless steel sheet. After the rotational molding process cools, the rotational molding mold 2 and the positioning pin 9 are disassembled. The outer end face of the positioning cylinder 8 will be partially exposed. Due to the corrosion resistance of stainless steel, the exposed end face does not need to be sealed, simplifying the process.

[0046] In another embodiment, please refer to Figures 5 to 7 The integrated anchor 4 can also be an integrated through-hole type anchor. Specifically, multiple evenly distributed first transverse through-holes 6 are stamped in the portion of the built-in core 3 near the outer periphery. The first transverse through-holes 6 form a non-concave structure, and the inner wall of the outer end (near the shell end) of the first transverse through-hole 6 is the anchoring surface 5. At this time, F=G. This allows the concave anchoring surface 5 formed by the first transverse through-hole 6 to fully engage with the shell 1 in the normal direction.

[0047] The other settings of this integrated through-hole anchor are basically the same as those of the aforementioned integrated tenon-and-mortise type anchor. The difference is that the first transverse through-hole 6 of this integrated through-hole anchor is a vertical hole, and the anchoring surface 5 is a horizontal plane. Therefore, the width W of the first transverse through-hole 6 and the normal distance G from the anchoring surface 5 to the outer surface of the shell 1 do not need to be obtained through calculation.

[0048] This integrated through-hole anchor can achieve the same technical effect as the integrated tenon and mortise type anchor. It can ensure that the internal skeleton 3 is firmly connected to the shell 1 and is not easy to detach. It can also open up the mold cavities on both sides, avoid plastic powder from entering the cavity, ensure uniform shell wall thickness, and improve molding quality and stability.

[0049] Example 2 The anchor in this embodiment is a variation of the integral through-hole type anchor in Embodiment 1.

[0050] Please see Figure 8 , Figure 9 The integrated outward-protruding oblique edge type anchor has an outward-protruding structure—outward-protruding oblique edge 12—on the first transverse through slot 6. The surface of the outward-protruding oblique edge 12 facing the inner end of the anchor 4 is an oblique surface, which is the anchoring surface 5. This can effectively enhance the mechanical limiting effect and increase the engagement area and engagement depth with the rotomolded shell 1.

[0051] Furthermore, the convex inclined edges 12 of adjacent first transverse through slots 6 can be arranged to convex outward to one side or to convex outward in an alternating manner, that is, adjacent convex inclined edges 12 face opposite directions, forming a bidirectional symmetrical anchoring structure, avoiding stress concentration, and further improving the overall structural strength and connection stability.

[0052] It should be noted that the dimensional relationship of this embodiment is consistent with that of the aforementioned integrated tenon and mortise type anchor. Because the anchoring surface 5 is the inclined surface of the outwardly convex inclined edge 12, the normal distance G from the anchoring surface 5 to the outer surface of the shell is the vertical distance from the midpoint of the inclined surface to the outer surface of the shell; the thickness E of the anchor is the thickness of the built-in rib 3.

[0053] Example 3 In Examples 1 and 2, the anchor 4 is an integral anchor, directly formed on the outer periphery of the built-in rib 3. In contrast, the anchor in this example is a separate anchor, where a separately manufactured anchor is fixed to the normal outer periphery of the built-in rib 3. The material of the separate anchor can differ from that of the built-in rib 3; it can be made of steel plate using a stamping process, resulting in higher efficiency and lower cost. Both structural forms can be flexibly selected based on the size, stress requirements, and production process of the rotationally molded component, balancing structural reliability and manufacturing economy.

[0054] In one implementation, please refer to Figure 10The split anchor 4 consists of several longitudinally grooved anchors arranged along the longitudinal direction of the built-in rib 3. The cross-section of this longitudinally grooved anchor is U-shaped, with a transverse flange 13 at the outer opening. Multiple first transverse through-holes 6 are formed on the sidewalls, allowing the anchor 4 to pass through laterally. Its inner end is fixedly connected to the built-in rib 3. This structure is easy to assemble, readily standardized for mass production, and offers good manufacturability and cost advantages. The U-shaped groove structure significantly increases the contact area between the anchor and the molten plastic. During rotational molding, the plastic can fully fill the groove, forming a strong mechanical fit and effectively improving the bonding strength between the anchor and the shell 1. The longitudinal arrangement evenly distributes the force along the longitudinal direction of the built-in rib 3, avoiding localized stress concentration and further enhancing the overall connection reliability between the built-in rib 3 and the shell 1.

[0055] Furthermore, the side of the transverse flange 13 facing the inner end of the anchor 4 forms an anchoring surface 5, which can further increase the contact area and interlocking force with the shell 1, effectively preventing the longitudinal groove anchor from coming off or loosening during use.

[0056] Specifically, the longitudinal groove anchor has multiple fixing holes 14 at the bottom of the groove. The outer diameter of the fixing hole 14 is smaller than the width of the groove bottom. The fixing holes 14 are used to reliably fix the longitudinal groove anchor to the built-in skeleton 3, including screw tightening and plug welding. This structure ensures connection strength while avoiding weakening the groove bottom rigidity due to excessively large openings. At the same time, molten plastic can penetrate into the through hole to form an additional fit, further improving the overall anchoring effect. The first transverse through groove 6 can be set as a circular hole, square hole, closed groove, or open comb-shaped groove, etc., and can be flexibly adjusted according to the actual working conditions.

[0057] Example 4 Please see Figures 11 to 14 In this embodiment, an integrated anchor and an integrated positioning cylinder are combined. Specifically, the integrated through-hole anchor 4 and positioning cylinder 8 of embodiment 1 are directly formed on the outer periphery of the built-in bone 3. The three are integrated and do not require secondary assembly and fixation.

[0058] The upper part of the positioning cylinder 8 protrudes from the surface of the integrated through-hole anchor 4, and the lower part is integrated with the integrated through-hole anchor 4. The second transverse through-hole coincides with the first transverse through-hole 6.

[0059] This embodiment has no assembly gaps or loosening risks. While ensuring anchoring reinforcement and uniform molding, it greatly simplifies the production and assembly process, effectively improves the mass production efficiency of large rotational molding components, and meets the processing requirements of high-precision and high-stability rotational molding products.

[0060] Example 5 Please see Figures 15 to 18This embodiment combines a split-type anchor with a split-type positioning cylinder, aiming to fully leverage the structural advantages of both types of anchors and positioning cylinders. This adapts to the more complex stress conditions, assembly requirements, and usage environments of rotomolded components, further improving the anchoring and positioning reliability, layout flexibility, and overall adaptability of the anchors. Specifically, it uses a combination of the longitudinal groove anchor of Embodiment 3 and the split-type positioning cylinder of Embodiment 1. The split-type positioning cylinder is positioned between adjacent longitudinal groove anchors, forming a complementary composite anchoring and positioning structure.

[0061] As described in Example 3, the longitudinal groove anchor and the split positioning cylinder can be individually processed and fixedly connected to the normal outer periphery of the built-in rib 3. Their materials can be different from those of the built-in rib 3. Higher strength materials or stainless steel materials can be selected according to requirements to balance load-bearing capacity and weather resistance and corrosion resistance. Even if partially exposed, they can effectively resist rust.

[0062] In this embodiment, the combined arrangement of the two types of split anchors adopts the principle of zoned adaptation: along the longitudinal direction of the built-in skeleton 3, in areas that need to bear longitudinally distributed loads and require a large contact area of ​​the anchoring surface, longitudinal groove-shaped anchors are arranged. The longitudinal arrangement can evenly distribute the force along the longitudinal direction of the built-in skeleton 3, effectively avoiding local stress concentration and adapting to the anchoring requirements of long distances and large areas. At the key stress points of the rotational molding component, irregular assembly areas, and positions that need to be normally connected with external components, split positioning cylinders are arranged. Their barrel-shaped structure effectively constrains and positions the built-in skeleton 3 during the rotational molding process, preventing the built-in skeleton 3 from shifting due to mold rotation and ensuring the dimensional accuracy of the component.

[0063] This embodiment, through the combined arrangement of longitudinal groove anchors and split positioning cylinders, fully leverages the advantages of the longitudinal groove anchors—large contact area and uniform force distribution—as well as the split positioning cylinders—precise positioning and adaptability to normal docking. The synergistic effect of these two components not only meets the complex assembly points and stress requirements of rotomolded components but also enhances the structure's weather resistance, corrosion resistance, and load-bearing strength through differentiated material selection. Simultaneously, it maintains the flexible assembly and easy mass production advantages of split anchors, further expanding the applicable scenarios of split anchors and adapting to the needs of more complex large rotomolded components.

[0064] Example 6 To further improve the assembly performance and structural scalability of rotationally molded components.

[0065] In one embodiment, please refer to Figure 19 , Figure 20The inner core 3 is further provided with connecting components on its outer periphery for connecting to external structural components of the shell. The connecting components are rigidly connected to the inner core 3. Specifically, the connecting components can be studs 7 or riveting studs that protrude normally from the outer surface of the shell, or embedded nuts with their outer ends flush with the outer surface of the shell 1. This type of connecting component can be regarded as a structural variant of the aforementioned anchor, which can not only achieve a reliable connection between the external components and the inner core 3, further strengthening the overall structural strength, but also be used for assembly after multi-section rotational molding to form ultra-large rotational molded structural components.

[0066] Furthermore, when it is necessary to connect two rotational molding components, one of the rotational molding components is also provided with multiple rigid conduits 19 that pass through the shell on both sides. The rigid conduits 19 are used to pass through studs 7 or connecting rods 18 to achieve docking connection with the other rotational molding component.

[0067] As shown in the figure, the inner skeleton 3 of the double-hulled rotomolded vessel (first rotomolded component 15) is also provided with studs 7 for connecting the external structural components of the hull. The studs 7 are rigidly connected to the outer periphery of the inner skeleton 3. The double-hulled rotomolded deck (second rotomolded component 16) is also provided with multiple rigid guide tubes 19 that pass through the opposite sides of the hull. The studs 7 are passed through the guide tubes 19 and then fastened with nuts. In this way, the double-hulled rotomolded deck 16 can be fixed to the double-hulled rotomolded vessel 15.

[0068] Similarly, by passing the connecting rod 18 through the conduit 19 and tightening it onto the post of the guardrail 20, which has a nut at the lower end, the guardrail 20 can be fixed to the double-layer rotomolded deck 16.

[0069] In another embodiment, please refer to Figure 19 , Figure 21 When the rotomolded component is connected to the non-rotomolded structural component, the rotomolded component is connected to the non-rotomolded structural component by the connecting rod 18 passing through it. The non-rotomolded structural component can be a flat keel 21.

[0070] In another embodiment, please refer to Figure 22 The first rotomolded component 15 (fore section of the hull) and the second rotomolded component 16 (rear section of the hull) are connected to form a larger combined rotomolded component via connecting rod 18 and guide tube 19. By rotomolding the components in sections and then assembling them, ultra-large combined rotomolded structural components can be manufactured efficiently, while ensuring the rigidity and stability of the spliced ​​parts. For example, five rotomolded hull sections, each 6 meters long, can be rotomolded separately and then assembled into a 30-meter-long rotomolded boat.

[0071] In another embodiment, please refer to Figures 23-25The first rotomolded component 15, the second rotomolded component 16, and the third rotomolded component 17, etc., are connected by connecting rod 18 and conduit 19 to form a larger combined rotomolded component (the figure shows a multi-layered combined ultra-large liquid storage tank). By rotomolding in sections and then assembling them, ultra-large combined rotomolded structural components can be manufactured efficiently, while ensuring the rigidity and stability of the splicing parts. For example, multiple rotomolded arc plates with an arc length of 5.2 meters and a height of 3-4 meters can be rotomolded separately and combined to form an ultra-large liquid storage tank with a diameter of 10 meters and a height of 10 meters.

[0072] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0073] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A built-in bone-strengthening rotational molded member comprising a rotational molded and hollow shell, characterized by, The inner cavity of the shell is provided with an internal skeleton. The normal outer periphery of the internal skeleton is provided with an anchor that intersects with the normal of the shell. The anchor has a non-outwardly convex structure or an inwardly concave structure to form an anchoring surface facing the inner end of the anchor. The normal distance G from the anchoring surface to the outer surface of the shell is less than the shell wall thickness B for normal anchoring of the shell. The anchor also has a first transverse through slot. The normal distance F from the outer end of the first transverse through slot to the outer surface of the shell is less than the shell wall thickness B for conducting the shell on both sides of the internal skeleton.

2. The rotomolded component with built-in reinforcement according to claim 1, characterized in that, The width W of the first transverse through slot is less than the wall thickness B of the shell; when the sidewall of the first transverse through slot is a non-parallel structure, its width W is the arithmetic mean of the maximum and minimum hole widths.

3. The rotomolded component with built-in reinforcement according to claim 2, characterized in that, The normal distance H from the inner end of the first transverse through slot to the outer surface of the shell is greater than the shell wall thickness B, and the longitudinal span L of two adjacent first transverse through slots is less than twice the slot width W, i.e., L < 2W.

4. The rotomolded component with built-in reinforcement according to claim 1, characterized in that, The normal distance C from the outer end of the anchor to the outer surface of the shell is less than D, the width W of the first transverse through slot is less than D, where D is the diameter of the large particles produced by the small particle aggregation effect, D=2d*E, where d is the average diameter of the rotational molding powder, and E is the thickness of the anchor.

5. A rotomolded component with built-in reinforcement according to claim 1, characterized in that, The embedded bone material has a positioning cylinder on its normal outer periphery. The positioning cylinder is barrel-shaped and has an opening at its normal outer end.

6. A rotomolded component with built-in reinforcement according to claim 5, characterized in that, The side wall of the positioning cylinder is provided with a second transverse through slot, and the opening is provided with a circumferential flange.

7. The rotomolded component with built-in reinforcement according to claim 1, characterized in that, The anchor includes a plurality of longitudinal groove anchors distributed along the longitudinal direction of the built-in rib. The cross-section of the longitudinal groove anchor is U-shaped, and the normal inner end is connected to the outer periphery of the built-in rib. The bottom of the groove of the longitudinal groove anchor is provided with a plurality of through holes with a circumscribed circle diameter smaller than the width of the groove bottom. The through holes are used to connect the anchor and the built-in rib.

8. A rotomolded component with built-in reinforcement according to claim 1 or 7, characterized in that, The anchor is an integral anchor and / or a split anchor. The integral anchor is directly formed on the outer periphery of the built-in bone material body; the split anchor is a separately manufactured anchor fixedly connected to the normal outer periphery of the built-in bone material.

9. The rotomolded component with built-in reinforcement according to claim 1, characterized in that, The outer periphery of the built-in skeleton is provided with a connecting component for connecting the outer structural component of the shell. The connecting component is rigidly connected to the built-in skeleton. The connecting component includes a stud or riveting stud that protrudes normally from the outer surface of the shell, or a nut whose outer end is flush with the outer surface of the shell.

10. The rotomolded component with built-in reinforcement according to claim 1, characterized in that, The rotational molding component is provided with multiple rigid conduits that pass through the shells on both sides, for passing through connecting rods that connect other structural components.

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