Handhole covers and manufacturing methods

Abstract

A cover for an enclosure and method for forming include providing, via a structural foam molding process, a mixture of a thermoplastic resin and a chemical foaming agent to a mold having walls configured correspondingly to end walls of the cover between which sidewalls extend. A cover wall extends includes a grid structure extending from the end walls and the sidewalls and from an inner face of the cover wall, and includes a plurality of walls extending from the inner face and from a plurality of nodes at an oblique angle from one another. A cellular structure is formed between external surfaces of the end walls, sidewalls, and cover wall by subjecting the mixture to heat to generate an inert gas from decomposition of the chemical foaming agent. Solid external surfaces of the end walls, sidewalls, and cover wall are formed by expanding the thermoplastic resin to mold walls.

Description

HANDHOLE COVERS AND MANUFACTURING METHODSPRIORITY STATEMENT

[0001] The present disclosure claims the benefit of priority to U.S. provisional patent application no. 63 / 711,890, filed on October 25, 2024, the disclosure of which is incorporated by reference herein in its entirety.FIELD

[0002] The present disclosure relates generally to containment vaults, also known as handholes, for use in various industries such as telecommunications, water, etc. More specifically, the present disclosure relates to covers for containments vaults.BACKGROUND

[0003] A significant problem with telecommunication handhole covers is that the lids require reinforcement members and challenging manufacturing methods to meet ANSI 77 Tier 22 requirements, which specifies load requirements for underground enclosures used in driveway, parking lot, and off-roadway areas. Such requirements require withstanding lateral forces of at least 150.1 kN, vertical forces of at least 100.1 kN, and a maximum pressure of 38.3 kPa. For fabrication, the covers are then generally compression molded with complex tooling.

[0004] Accordingly, improved handholes and covers therefor would be advantageous. Specifically, handholes and covers therefor which address one of more of the above-stated deficiencies would be advantageous.BRIEF DESCRIPTION

[0005] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0006] An aspect of the present disclosure is directed to a cover for a telecommunications enclosure. The cover is a unitary, monolithic thermoplastic or thermoplastic composite component having end walls between which sidewalls extend. A cover wall extends between the end walls and the sidewalls and has anouter face and an inner face. A grid structure extends from the end walls and the sidewalls and from the inner face of the cover wall. The grid structure includes a plurality of walls extending along a depth direction from the inner face and from a plurality of nodes. The plurality of walls extend from the plurality of nodes at an oblique angle from one another. A cellular structure extends between external surfaces of the end walls, sidewalls, and cover wall. External surfaces of the end walls, sidewalls, and cover wall are solid external surfaces.

[0007] An aspect of the present disclosure is directed to a method for forming the cover. The method includes providing, via a structural foam molding process, a mixture of a thermoplastic resin and a chemical foaming agent to a mold. The mold includes mold walls configured correspondingly to the end walls between which the sidewalls extend. The cover wall extends between the end walls and the sidewalls, and the grid structure extends from the end walls and the sidewalls and from the inner face of the cover wall. The method includes forming the cellular structure between external surfaces of the end walls, sidewalls, and cover wall by subjecting the mixture to heat to generate an inert gas from decomposition of the chemical foaming agent. The method includes forming the solid external surfaces of the end walls, sidewalls, and cover wall by expanding, from a foaming process from generating the inert gas, the thermoplastic resin to mold walls.

[0008] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

[0010] Fig. 1 provides a perspective view of an exemplary embodiment of an enclosure in accordance with aspects of the present disclosure;

[0011] Fig. 2 provides a top perspective view of an exemplar}' embodiment of a cover for an enclosure in accordance with aspects of the present disclosure;

[0012] Fig. 3 provides a bottom perspective view of the exemplary embodiment of the cover of Fig. 2 in accordance with aspects of the present disclosure;

[0013] Fig. 4 provides a plan view of a bottom side of the exemplary embodiment of the cover of Fig. 2 in accordance with aspects of the present disclosure;

[0014] Fig. 5 provides a first perspective cross-sectional view of the exemplary embodiment of the cover of Fig. 2 in accordance with aspects of the present disclosure;

[0015] Fig. 6 provides a second perspective cross-sectional view of the exemplary embodiment of the cover of Fig. 2 in accordance with aspects of the present disclosure;

[0016] Fig. 7 provides a detailed cross-sectional view of a cellular structure and external surfaces of the cover of Fig. 2 in accordance with aspects of the present disclosure;

[0017] Fig. 8 provides a flowchart outlining steps of a method for forming a cover in accordance with aspects of the present disclosure; and

[0018] Fig. 9 provides a perspective view of an exemplary' mold for manufacturing embodiments of the cover in accordance with aspects of the present disclosure.

[0019] Use of the same of similar reference numerals in the figures denotes the same or similar features unless the context indicates otherwise.DETAILED DESCRIPTION

[0020] Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still furtherembodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0021] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “includes” and “including” are intended to be inclusive in a manner similar to the term “comprising.” Similarly, the term “or” is generally intended to be inclusive (i. e. , “A or B” is intended to mean “A or B or both”). In addition, here and throughout the specification and claims, range limitations may be combined and / or interchanged. Such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.

[0022] Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “generally,” “about,” “approximately,” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value, or the precision of the methods or machines for constructing or manufacturing the components and / or systems. For example, the approximating language may refer to being within a 10 percent margin, i.e., including values within ten percent greater or less than the stated value. In this regard, for example, when used in the context of an angle or direction, such terms include within ten degrees greater or less than the stated angle or direction, e.g., “generally vertical” includes forming an angle of up to ten degrees in any direction, e.g., clockwise, or counterclockwise, with the vertical direction V.

[0023] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” In addition, references to “an embodiment” or “one embodiment” does not necessarily refer to the same embodiment, although it may. Any implementation described herein as “exemplary” or “an embodiment” is notnecessarily to be construed as preferred or advantageous over other implementations. Moreover, each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0024] Referring now to the drawings, Fig. 1 provides a top, front, perspective view of an exemplary embodiment of a utility enclosure 10 at which embodiments of a cover 100 (Figs. 2-6) may be positioned. The utility enclosure 10 is rectangular and includes a first side 11, a second side 12 opposite the first side 11, a third side 13, and a fourth side 14 opposite the third side 13. The first side 11 and the second side 12 form a first pair of sides and the third side 13 and the second side 14 form a second pair of sides. The utility enclosure 10 includes atop end 15. a bottom end 16. and an interior volume 17. An interior ledge 18 is formed on each side in the interior volume 17 near the top end 15 to support a cover (Figs. 2-6).

[0025] In various embodiments, the edges of each side 11, 12, 13, 14 may be joined together with hinges 20, 21. 22. and 23 to form the rectangular utility enclosure 10, with a hinge in each comer of the rectangle. The hinges 20, 21, 22, and 23 include hinge members 24 each having a central hole for the insertion of a hinge pin 26 to form the hinge. The hinge members 24 are formed in open hollow housings 27, the housings 27 having interiors 28.

[0026] First side 11 includes a first end 30 opposite of a second end 31. The second side 12 includes a first end 32 opposite of a second end 33. The third side 13 includes a first end 34 opposite of a second end 35. The fourth side 14 includes a first end 36 opposite of a second end 37. The first ends 30 and 32 of the sides 11 and 12 (e.g., first pair of sides) form curved comers which end with curved extensions 38. The second opposite ends 31 and 33 of sides 11 and 12 are also curved and form acute angles 39. The first ends 34 and 36 of sides 13 and 14 (e.g., second pair of sides) and the second opposite ends 35 and 37 of sides 13 and 14 form obtuse angles 40.

[0027] The first ends 34 and 36 of the sides 13 and 14 fit over the curved extensions 38 of sides 11 and 12 and the first ends 34 and 36 may be slightly curved to match the curved extensions 38. The second opposite end 35 of the third side 13 forms an obtuse angle 40 between an interior surface of the third side 13 and an interior surface of the first side 11. The obtuse angle 40 extends from the top end 15 of the utility enclosure 10 to the bottom end 16 of the utility enclosure 10. The second opposite end 37 of the fourth side 14 forms an acute angle 39 between an interior surface 45 A of the fourth side 14 and an interior surface 42 of the first side 11 and the acute angle 39 extends from the top end 15 of the utility enclosure 10 to the bottom end 16 of the utility' enclosure 10. The angled edges of the second opposite ends 35 and 37 of sides 13 and 14 abut the angled edges of the ends 31 and 33 of the sides 11 and 12. The sides 11, 12, 13, and 14 may have openings 19 to accommodate wires, pipes, tubing, and the like.

[0028] Referring now to Figs. 2-6, an embodiment of a cover 100 for a utility enclosure is provided, such as an embodiment of the utility enclosure 10 depicted and described in regard to Fig. 1. The cover 100 includes end walls 112 between which sidewalls 114 extend. A rounded comer 116 may form a transition between an end wall 112 and a pair of sidewalls 114. The sidewalls 114 may extend substantially along a first axis greater than a second axis along which the end walls 112 extend substantially and perpendicular to the first axis.

[0029] In various embodiments, the end walls 112 and the sidewalls 114 may form the cover 100 as a substantially rectangular body. Sidewalls 114 extend substantially corresponding to sides 11, 12 of the enclosure (Fig. 1), and end walls 112 extend substantially corresponding to sides 13, 14 of the enclosure (Fig. 1). Rounded comers 116 may include radii and transitions corresponding to ends 30, 31, 32, 33 of enclosure 10 (Fig. 1).

[0030] A cover wall 120 extends between the end walls 112 and the sidewalls 114. The cover wall 120 includes an outer face 121 that may substantially receive forces during usage. Such forces may correspond to vertical forces received from, for instance, foot traffic, vehicle traffic, or loads of earth or material onto the cover 100. Such forces may correspond to those received from driveway, parking lot, and offroadway area usage.

[0031] The cover wall 120 may include bumps, protrusions, or other raised surfaces 122 extending from the outer face 121. The raised surfaces 122 may provide grip and texture that may mitigate slippage.

[0032] The cover 100 includes a grid structure 130 extending from the end walls 112, the sidewalls 114, and an inner face 134 of the cover wall 120. The grid structure 130 is positioned in a volume bounded by the inner face 134 of the cover wall 120 and interior surfaces 132 of the end walls 112 and sidewalls 114. The grid structure 120 provides structural support, strength, and durability to the cover 100, such as further described herein.

[0033] The grid structure 130 is formed from a plurality of walls 136 extending from the inner face 132 of the cover wall 120. The plurality of walls 136 form nodes 138 at which three or more of the walls 136 meet from different angular directions. In various embodiments, the grid structure 130 includes three or more walls 136 extending from the node 138 at an oblique angle A from one another. In some embodiments, the grid structure 130 includes three or more walls 136 extending from the node 138 at angle A approximately 120 degrees from one another. In some embodiments, the grid structure 130 includes three or more walls 136 extending from the node 138 at angle A at approximately 60 degrees from one another, or approximately 45 degrees from one another, or approximately 30 degrees from one another.

[0034] In various embodiments, the grid structure 130 includes the plurality of walls 136 forming a plurality of hexagons within the area bounded by the end walls 112 and the sidewalls 114. The hexagonal arrangement of the plurality7of walls 136 of the grid structure 130 may particularly provide increased strength for lateral and vertical loads exerted upon the cover 100. Such increased strength for lateral and vertical loads may facilitate achieving ANSI 77 Tier 22 requirements for enclosures for telecommunications and low-voltage usage.

[0035] In some embodiments, walls 136 extend from the inner face 134 of the cover wall 120 along a depth direction D no greater than an extension of the end walls 112, sidewalls 114, or both along the depth direction D. For instance, an edge 142 of the walls 136 distal to the inner face 134 is flush or co-planar to an edge 144 of the end walls 112, sidewalls 114, or both. The limited extension of the end walls 112,sidewalls 114, or walls 136 of the grid structure 130 relative to one another may facilitate limiting weight of the cover 100. In various embodiments, the polygonal grid structure 130, such as having angles A extending from nodes 138 or forming a hexagonal arrangement described herein, may facilitate limiting the extension of the walls 112, 114, 136 such as described, such as may decrease weight while providing the strength required for lateral and vertical forces as described herein.

[0036] Referring briefly to Fig. 1, and further in regard to Figs. 2-6, walls 112, 114, 116 may be formed to fit within the interior volume 17 and rest upon the interior ledge 18. As such, exterior surfaces 119 of walls 112, 114, 116 may abut corresponding internal faces of sides 11, 12, 13, 14 and ends 30, 31, 32, 33. Walls 112, 114. 116 may be formed thin such that some of the walls 136 of the grid structure 130 may extend vertically adjacent to the interior ledge 18 (Fig. 1) of the enclosure 10.

[0037] In some embodiments, walls 136 of the grid structure 130 may extend along the depth direction D from the inner face 134 of the cover wall 120 such that edges 142 abut the interior ledge 18 (Fig. 1) of the enclosure 10. The edges 142 may be formed substantially co-planar throughout the grid structure 130, such as positioned similarly to one another along the depth direction D from the inner face 134. The cover 100 may further facilitate a flush extension of the outer face 121 of the cover wall 120 with the top end 15 (Fig. 1) of the enclosure 10. As such, embodiments of the cover 100 including the grid structure 130 such as provided herein may provide desired strength as described herein while fitting within the enclosure 10 such as described.

[0038] Referring back to Figs. 2-6, in some embodiments, the cover wall 120 forms an emboss 128 extended into the outer face 121. The emboss 128 may form an area at which a label may be positioned. The emboss 128 may extend into the cover wall 120 along a depth without altering a profile of the inner face 134 of the cover wall 120. For instance, the inner face 134 may extend substantially flat or planar. Outer and inner faces 121, 134 may extend substantially co-directional to one another, such as may form a substantially even thickness of the cover wall 120 between the faces 121, 134.

[0039] In some embodiments, the faces 121, 134 may form a substantially even thickness except at the emboss 128. The emboss 128 may be positioned approximately center between the end walls 112 and sidewalls 114, such that loads or forces applied to the cover 100 may evenly react to the difference in thickness relative to the emboss 128.

[0040] In some embodiments, one or more of end wall 112, sidewall 114, or both may include a tab 118 extending from an exterior surface 119. The tab 118 may be configured to catch into an opening, slot, or latch at the enclosure. While depicted as extending from the end wall 112, it should be appreciated that tab 118 may extend, additionally or alternatively, from sidewall 114.

[0041] In some embodiments, the exterior and interior surfaces 119, 132 of the end walls 112, sidewalls 114, or both, may form a substantially even thickness of the wall therebetween. For instance, the surfaces 119, 132 may extend substantially co-directional to one another, such as may form a substantially even thickness of the cover 100 between the surfaces 119, 132.

[0042] In some embodiments, the cover wall 120 includes a cavity 124 extending through the outer face 121. A member 126 may extend through the cavity 124. The member 126 may provide a bar or rod at which a user may attach a latch or rope, such as may be utilized for pulling the cover 100 from the enclosure.

[0043] In still some embodiments, the cover 100 may include cavity walls 125 forming an opening 127 extending through the inner face 134 of the cover wall 120. The cavity walls 125 may be formed at an intersection of walls 136, such as may occupy a position at which a node 138 is arranged between the end walls 112 and sidewalls 114. The opening 127 may extend in fluid communication with the cavity 124 extending from the outer face 121. However, in some embodiments, the opening 127 and cavity 124 may be fluidly segregated from one another, such that no opening is provided through the cover wall 120 from the outer and inner faces 121, 134.

[0044] In various embodiments, the cover 100 includes a porous, cellular structure 150 formed between external surfaces of the cover 100. The porous, cellular structure 150 is formed between substantially smooth external surfaces, such as exterior and interior surfaces 119, 132 and outer and inner faces 121, 134. The porous, cellular structure 150 facilitates providing the cover 100 with desired strength against lateraland vertical forces while also reducing density and corresponding weight of the cover 100, such as in contrast to non-porous structures formed from compression molding processes.

[0045] Referring to Fig. 7, a detailed cross-sectional view of the cover 100 depicting the external surfaces 119, 121, 132, 134 and the cellular structure 150 positioned therebetween is provided. In various embodiments, the cover 100 is formed from a structural foam molding process or an injection molding process, providing the porous, cellular structure 150 between the substantially smooth external surfaces 119, 121, 132, 134.

[0046] Referring to Fig. 8, the cover 100 is formed from a structural foam molding process. The structural foam molding process includes a low-pressure injection molding process that provides for the cover 100 a relatively thick, lightweight, and strong plastic component by mixing a polymer with an inert gas (such as, but not limited to, carbon dioxide or nitrogen) or a chemical blowing agent, such as may be provided through port 160 (Figs. 3-4). The gas expands the plastic material as the material is injected into the mold, forming a solid external skin, such as at surfaces 119, 121, 132, 134, and a porous, cellular honeycomb core structure 150 between the surfaces 119, 121, 132, 134. The structural foam molding process reduces component weight and material usage while preventing undesired sink and swirl marks.

[0047] In various embodiments, the cover 100 is formed from a thermoplastic polymer with which the inert gas or chemical blowing agent is mixed. The plastic / gas mixture is injected (e.g., as provided at port 160) into a mold under low pressure, in contrast to relatively high pressures with which molten plastic is subjected in a compression molding process. As the plastic / gas mixture enters the mold, the gas or blowing agent expands and causes the thermoplastic to foam and generate the cellular structure 150. The expanding foamed plastic contacts a cold mold wall, which solidifies the plastic to form a dense, solid outer surfaces 119, 121, 132, 134. The expanding gas fills the mold cavity’ and generates the porous, cellular honeycomb core structure 150 between the external surfaces. As the component cools and solidifies, the finished cover 100 is formed with the solid external surfaces 119, 121, 132, 134 and the foamed cellular structure 150 interior.

[0048] The foaming action provides the pressure required for filling the mold. The required pressure is less than that for a conventional injection molding or compression molding process. The structural foam molding process provides the finished component with strong, dense external surfaces and a less dense, foam cellular core structure. The cellular core structure 150 significantly reduces the weight of the finished cover, in contrast to finished components formed from conventional injection or compression molding, and without compromising structural integrity, such as to provide strength for meeting or exceeding ANSI 77 Tier 22 requirements.Additionally, internal foaming from the structural foaming process helps to counteract shrinkage and prevent the formation of sink or swirl marks on external surfaces of the component.

[0049] In contrast, a conventional compression molding process provides a thermoset or thermoplastic material into a heated mold and compresses the material under pressure to fill a cavity. The compression molding process provides the finished part with substantially similar density and physical properties across an outer surface and internal structure, rather than a cellular structure between solid, more dense exterior surfaces such as provided with structural foam molding. The resulting structure from compression molding generally has a greater weight than similarly sized components of similar materials. For instance, the cover 100 formed from the structural foaming process is between approximately 10% to approximately 30% less dense than similarly dimensioned components of similar material from a conventional injection molding, and having corresponding decrease in weight, and further decrease in contrast to a compression molding process.

[0050] Furthermore, conventional injection molding processes may result in undesired sink or swirl marks that may result from material shrinkage during the manufacturing process.

[0051] To achieve a desired strength for withstanding breakage and deformation, strength members such as metal reinforcement bars (rebar) are generally included in covers. Such strength members require tooling and fixturing, such as a cradle and subsequent voids in the cover, for positioning the strength member relative to the surrounding plastic material during the molding process. In contrast, embodiments of the cover formed using a structural foam molding process remove a need forembedded or over-molded strength members by facilitating the formation of polygonal (e.g., hexagonal) grid patterns within the area between the sidewalls of the lid.

[0052] Additionally, embodiments of the cover such as provided herein may facilitate a more robust and repeatable process by removing the need for consistent positioning of rebar or other strength members to a tooling fixture and relative to a surrounding plastic material.

[0053] In an exemplary embodiment, the cover 100 is formed from a structural foam molding process including an endothermic chemical foaming agent (CFA) yielding a carbon dioxide gas. The endothermic CFA includes a carbonate-based or poly carbonic acid-based agent configured to generate carbon dioxide during decomposition.

[0054] In another exemplary embodiment, the cover 100 is formed from a structural foam molding process including an exothermic CFA yielding a nitrogen gas. The exothermic CFA may generate larger internal cells and greater density reduction than the cover formed using the endothermic CFA. The exothermic CFA may include an azodicarbonamide (ADC)-based agent configured to generate nitrogen gas during decomposition.

[0055] Covers 100 depicted and described herein provide handhole covers and handholes that may solve the above-identified challenges by providing a lid including polygonal grid structures formed using a structural foam molding or injection molding process. Embodiments of the cover 100 depicted and described herein may exclude internal or overmolded strength members, such as metal reinforcement bars, which may simply the manufacturing process, reduce weight, while providing desired strength properties in accordance with ANSI 77 Tier 22 requirements.

[0056] Referring now to Fig. 8, a flowchart outlining steps of a method for manufacturing a cover for an enclosure is provided (hereinafter, “method 1000”). Steps of the method 1000 provided herein may be utilized for forming embodiments of the cover 100 such as depicted and described herein.

[0057] Method 1000 includes at 1010 providing, via a structural foam molding process, a mixture of a thermoplastic resin and a chemical foaming agent to a mold, such as outlined in Fig. 9 at mold 1100. The mold 1100 includes mold wallsconfigured correspondingly to end walls 112 between which sidewalls 114 extend, the cover wall 120 extending between the end walls 112 and the sidewalls 114. and the grid structure 130 extending from the end walls 112 and the sidewalls 114 and from the inner face 134 of the cover wall 120. The mold 1100 further corresponds to the plurality of walls 136 of the grid structure 130, such as extending along the depth direction D from the inner face 134 and from the plurality of nodes 138 at an oblique angle A.

[0058] Method 1000 includes at 1020 forming a cellular structure (e g., cellular structure 150) between external surfaces of the end walls 112, sidewalls 114, and cover wall 120 (e.g., external surfaces 119, 121, 132, 134) by subjecting the thermoplastic resin and CFA mixture to heat to generate an inert gas from decomposition of the chemical foaming agent.

[0059] In various embodiments, the heat is at least 165 degrees Celsius to decompose the chemical foaming agent and generate the inert gas to expand the thermoplastic resin to the mold walls to form the end walls 112, sidewalls 114, cover wall 120. and grid structure 130. or furthermore, rounded comers 116 and other features such as described in regard to cover 100.

[0060] Method 1000 includes at 1030 forming solid external surfaces of the end walls, sidewalls, and cover wall by expanding, from a foaming process from generating the inert gas, the thermoplastic resin to mold walls. The method 1000 may include maintaining the mold walls at a relatively cooler temperature (e.g., less than 165 degree Celsius) to facilitate forming the solid, non-porous external surfaces of the end walls, sidewalls, and cover wall, or furthermore, rounded comers and other features such as described in regard to cover 100.

[0061] As described herein, in various embodiments of the method 1000, the chemical foaming agent includes an endothermic chemical foaming agent. The endothermic chemical foaming agent may include a carbonate or poly carbonic acid. The inert gas from decomposition of the chemical foaming agent includes a carbon dioxide gas.

[0062] As described herein, in still various embodiments of the method 1000, the chemical foaming agent includes an exothermic chemical foaming agent. Theendothermic chemical foaming agent may include an azodicarbonamide. The inert gas from decomposition of the chemical foaming agent includes a nitrogen gas.

[0063] Various embodiments of the cover 100 and method 1000 provide a unitary, monolithic thermoplastic or thermoplastic composite component. In various embodiments, the thermoplastic resin includes a glass fiber-reinforced composite, a polypropylene, a thermoplastic polymer-graphene composite, or other thermoplastic polymers or reinforcing fibers.

[0064] In still various embodiments, method 1000 may provide for forming a cover including strength properties in accordance with ANSI 77 Tier 22 requirements and without providing other materials or structures to a void formed between mold walls 1110. such as excluding strength members such as metal reinforcements.Embodiments of the method 1000 and cover 100 depicted and described herein may provide advantages and benefits such as described herein and provide solutions to one or more problems described herein.

[0065] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

WHAT IS CLAIMED IS:

1. A method for forming a cover for an enclosure, the method comprising: providing, via a structural foam molding process, a mixture of a thermoplastic resin and a chemical foaming agent to a mold, the mold having mold walls configured correspondingly to end walls between which sidewalls extend, a cover wall extending between the end walls and the sidewalls, the cover wall having an outer face and an inner face, and a grid structure extending from the end walls and the sidewalls and from the inner face of the cover wall, the grid structure comprising a lurality of walls extending along a depth direction from the inner face and from a plurality of nodes, the plurality' of walls extending from the plurality of nodes at an oblique angle from one another;forming a cellular structure between external surfaces of the end walls, sidewalls, and cover wall by subjecting the mixture to heat to generate an inert gas from decomposition of the chemical foaming agent; andforming solid external surfaces of the end walls, sidewalls, and cover wall by expanding, from a foaming process from generating the inert gas. the thermoplastic resin to mold walls.

2. The method of claim 1, the mold having mold walls configured corresponding to the grid structure comprising the plurality of walls forming a plurality of adjacent hexagonal arrangements extending from the end walls and the sidewalls and the inner face of the cover wall.

3. The method of claim 1. the mold having mold walls corresponding to an edge of the plurality of walls of the grid structure extending along the depth direction from the inner face no greater than an extension of the end walls, the sidewalls, or both along the depth direction.

4. The method of claim 1. wherein providing the mixture of the thermoplastic resin and the chemical foaming agent to the mold comprises providing the mixture to a void free of a strength member.

5. The method of claim 1, wherein forming the cellular structure comprises subjecting the mixture to a temperature of at least 165 degrees Celsius to decompose the chemical foaming agent.

6. The method of claim 1, wherein the chemical foaming agent comprises an endothermic chemical foaming agent.

7. The method of claim 6, wherein the inert gas from decomposition of the chemical foaming agent comprises a carbon dioxide gas.

8. The method of claim 7, wherein the endothermic chemical foaming agent comprises a carbonate or poly carbonic acid.

9. The method of claim 1 , wherein the chemical foaming agent comprises an exothermic chemical foaming agent.

10. The method of claim 9, wherein the inert gas from decomposition of the chemical foaming agent comprises a nitrogen gas.

11. The method of claim 10, wherein the exothermic chemical foaming agent comprises an azodicarbonamide.

12. The method of claim 1, wherein the thermoplastic resin comprises a glass fiber-reinforced composite.

13. The method of claim 1, wherein the thermoplastic resin comprises a polypropylene.

14. The method of claim 1. wherein the thermoplastic resin comprises a thermoplastic polymer-graphene composite.

15. A cover for a telecommunications enclosure, the cover consisting essentially of:a unitary, monolithic thermoplastic or thermoplastic composite component comprising end walls between which sidewalls extend, a cover wall extending between the end walls and the sidewalls, the cover wall having an outer face and an inner face, and a grid structure extending from the end walls and the sidewalls and from the inner face of the cover wall, the grid structure comprising a plurality of walls extending along a depth direction from the inner face and from a plurality of nodes, the plurality of walls extending from the plurality of nodes at an oblique angle from one another, wherein a cellular structure extends between external surfaces of the end walls, sidewalls, and cover wall, and wherein external surfaces of the end walls, sidewalls, and cover wall comprises solid external surfaces.

16. The cover of claim 15, wherein the grid structure comprises the plurality of walls forming a plurality of adjacent hexagonal arrangements extending from the end walls and the sidewalls and the inner face of the cover wall.

17. The cover of claim 15, wherein an edge of the plurality of walls of the grid structure extends along the depth direction from the inner face no greater than an extension of the end walls, the sidewalls, or both along the depth direction.

18. A method for forming the cover of claim 15, the method comprising:providing, via a structural foam molding process, a mixture of a thermoplastic resin and a chemical foaming agent to a mold, the mold having mold walls configured correspondingly to the end walls between which the sidewalls extend, the cover wall extending between the end walls and the sidewalls, and the grid structure extending from the end walls and the sidewalls and from the inner face of the cover wall;forming the cellular structure between external surfaces of the end walls, sidewalls, and cover wall by subjecting the mixture to heat to generate an inert gas from decomposition of the chemical foaming agent; andforming the solid external surfaces of the end walls, sidewalls, and cover wall by expanding, from a foaming process from generating the inert gas, the thermoplastic resin to mold walls.

19. The method of claim 18, wherein providing the mixture of the thermoplastic resin and the chemical foaming agent to the mold comprises providing the mixture to a void free of a strength member.

20. The method of claim 18, wherein forming the cellular structure comprises subjecting the mixture to a temperature of at least 165 degrees Celsius to decompose the chemical foaming agent.

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