The present disclosure relates to a pullbox for enclosing utilities that has a knockout section with a reduced thickness so that conduit apertures can be more easily created through the knockout section and provide access to the utilities.
Pullboxes are generally positioned in the ground and house various conduits and wires for utilities such as electrical systems, plumbing systems, water systems, etc. A manhole cover placed on top of the pullbox selectively encloses the utilities within the pullbox. In some prior art systems, the pullbox is cast in place, meaning forms are positioned at the in-ground location, and concrete is poured into the forms to create the pullbox. With in-place casting, various conduits can extend through the forms based on the positions of wires and conduits outside of the pullbox and the actual or expected positions of utilities within the pullbox. Then, when the concrete is poured, the conduits are in the correct position to provide access to the utilities.
One trend in concrete structures is manufacturing structures such as pullboxes offsite in a controlled environment and then delivering the precast concrete structure to the construction site for final installation. Precast concrete offers many advantageous such as quality control, speed of production, and reduced costs. However, in the case of a pullbox, the structure is made offsite without knowing precisely where a conduit or wire is supposed to pass through the pullbox and into the pullbox. Thus, once installed, part of the wall of the pullbox is chiseled or drilled to create an ad hoc aperture through the wall of the pullbox to allow conduit or wires to pass through the pullbox. Creating these apertures requires considerable time and related expense and can cause unintended effects such as crack propagation through the entire body of the pullbox. Thus, there is a need for a precast pullbox that can accommodate the creation of apertures through the pullbox for conduits and wires.
The present disclosure provides a precast concrete pullbox, and methods for manufacturing the same, that has one or more knockout sections with reduced thickness through which to create an aperture for conduits or wires. The reduced thickness equates to reduced effort to create such apertures, and the knockout sections also limit the propagation of any cracks or unintended consequences of creating an aperture through the pullbox. Other benefits and aspects of the disclosure are described in further detail below.
It is an aspect of various embodiments of the present disclosure to provide a knockout section with a taper surface that helps release the pullbox from a mold during manufacturing. A taper surface extends outwardly from a surface of the knockout section to an outer surface of a sidewall of the pullbox. If this surface were not tapered and were instead perpendicular to the surface of the knockout section, then the force required to separate the pullbox from the mold would have to overcome friction and shear forces created by the perpendicular surface and the mold. Instead, with a tapered surface, the shear forces and friction are reduced, and less force is needed to release the pullbox from a mold. The taper surface may also prevents accumulation of moisture on the outer surface of the pullbox. In addition, the taper surface can have an arcuate top portion and/or bottom portion to further promote these aspects of the disclosure.
It is a further aspect of various embodiments of the present disclosure to provide a reinforcement mesh that is embedded in the sidewall of the pullbox. The reinforcement mesh can have crisscrossing members made from a material such as metal to provide further strength to the pullbox. In some embodiments, the members and the spaces therebetween are positioned in a predetermined fashion with respect to the knockout section. Then, an end user with knowledge of the position of the reinforcement mesh can chisel, drill, or otherwise create an aperture through the knockout section and through a space between members to avoid eliminating any portion of the reinforcement mesh or exposing the reinforcement mesh to the environment.
It is a further aspect of various embodiments of the present disclosure to provide knockout sections in the sidewall of a pullbox but maintain the overall structural integrity of the pullbox. When viewed from above, the knockout section extends around a portion of the perimeter of the pullbox, and multiple knockout sections can extend along multiple portions of the perimeter. In various embodiments, the portion or portions of the perimeter occupied by the knockout sections is less than the portion or portions occupied by the non-knockout sections. Thus, even if apertures are created in all knockout sections and the knockout sections provide less structural support to the overall pullbox, the non-knockout sections maintain the integrity of the pullbox.
One specific embodiment of the present disclosure is a precast concrete pullbox for enclosing utilities, comprising at least one sidewall defining an enclosed volume; a reinforcement mesh embedded in the at least one sidewall, wherein the reinforcement mesh comprises a plurality of horizontal members crossing a plurality of vertical members to form spaces between the horizontal and vertical members; and a knockout section with a reduced thickness positioned in an outer surface of the at least one sidewall, wherein a taper surface extends outwardly from a surface of the knockout section to the outer surface of the at least one sidewall, and the taper surface has an arcuate top portion and an arcuate bottom portion to promote the release of the pullbox from a mold.
In some embodiments, the knockout section is part of a plurality of knockout sections, and the plurality of knockout sections extends around a perimeter of the at least one sidewall that is less than a perimeter of non-knockout sections to maintain structural integrity of the pullbox. In various embodiments, a horizontal member of the plurality of horizontal members is vertically aligned with a corner between a side edge of the taper surface and the arcuate top portion, and a vertical member of the plurality of vertical members is horizontally aligned with the side edge of the taper surface so that a location of the spaces between the horizontal and vertical members is predetermined relative to the knockout section.
In various embodiments, the taper surface has a constant slope from the surface of the knockout section to the outer surface of the at least one sidewall. In some embodiments, the at least one sidewall is a single sidewall having a cylindrical shape. In various embodiments, the pullbox further comprises a cover body positioned on the upper end of the at least one sidewall, wherein the cover body defines an opening in which the cover is disposed to provide selective access to the enclosed volume. In some embodiments, the pullbox further comprises a second reinforcement mesh positioned in a bottom wall that defines the enclosed volume, wherein the second reinforcement mesh comprises a plurality of first members crossing a plurality of second members, wherein the members are made from rebar. In various embodiments, the pullbox further comprises a cover positioned on an upper end of the at least one sidewall to further define the enclosed volume and provide selective access to the enclosed volume.
Another particular embodiment of the present disclosure is a method of forming a precast concrete pullbox for enclosing utility components, comprising (i) providing a mold having a central core and at least one mold plate, wherein the at least one mold plate has an inwardly-oriented protrusion that defines a knockout section with a reduced thickness; (ii) wrapping a reinforcement mesh around the central core, wherein the reinforcement mesh comprises a plurality of horizontal members crossing a plurality of vertical members; (iii) positioning the at least one mold plate around the reinforcement mesh and the central core; (iv) pouring a concrete mix into a space between the central core and the at least one mold plate and allowing the concrete mix to cure; and (v) moving the at least one mold plate away from the central core with a predetermined force to release a resulting pullbox that has the knockout section, wherein a taper surface extends outwardly from a surface of the knockout section to an outer surface of at least one sidewall of the pullbox, and the taper surface has an arcuate top portion and an arcuate bottom portion to promote release of the pullbox from the mold.
In some embodiments, the method further comprises (vi) securing a spacer to a horizontal member or a vertical member of the reinforcement mesh to offset the reinforcement mesh from an outer surface of the central core. In various embodiments, the at least one mold plate comprises a first mold plate and a second mold plate, wherein the protrusion extends from an inner surface of the first mold plate to define the knockout section, and a second protrusion extends from an inner surface of the second mold plate to define a second knockout section.
The Summary is neither intended nor should it be construed as being representative of the full extent and scope of the present disclosure. The present disclosure is set forth in various levels of detail in the Summary as well as in the attached drawings and the Detailed Description and no limitation as to the scope of the present disclosure is intended by either the inclusion or non-inclusion of elements or components. Additional aspects of the present disclosure will become more readily apparent from the Detailed Description, particularly when taken together with the drawings.
The above-described embodiments, objectives, and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the disclosure are possible using, alone or in combination, one or more of the features set forth above or described in detail below.
The phrases “at least one,” “one or more,” and “and/or,” as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B, and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” “one or more of A, B, or C,” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B, and C together.
Unless otherwise indicated, all numbers expressing quantities, dimensions, conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.”
The term “a” or “an” entity, as used herein, refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more,” and “at least one” can be used interchangeably herein.
The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Accordingly, the terms “including,” “comprising,” or “having” and variations thereof can be used interchangeably herein.
It shall be understood that the term “means” as used herein shall be given its broadest possible interpretation in accordance with 35 U.S.C. § 112(f). Accordingly, a claim incorporating the term “means” shall cover all structures, materials, or acts set forth herein, and all of the equivalents thereof. Further, the structures, materials, or acts and the equivalents thereof shall include all those described in the Summary, Brief Description of the Drawings, Detailed Description, Abstract, and claims themselves.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the disclosure and together with the Summary given above and the Detailed Description of the drawings given below, serve to explain the principles of these embodiments. In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the disclosure is not necessarily limited to the particular embodiments illustrated herein. Additionally, it should be understood that the drawings are not necessarily to scale.
Similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a letter that distinguishes among the similar components. If only the first reference label is used, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.
A list of the various components shown in the drawings and associated numbering is provided herein:
The present disclosure has significant benefits across a broad spectrum of endeavors. It is the Applicant's intent that this specification and the claims appended hereto be accorded a breadth in keeping with the scope and spirit of the disclosure being disclosed despite what might appear to be limiting language imposed by the requirements of referring to the specific examples disclosed. To acquaint persons skilled in the pertinent arts most closely related to the present disclosure, a preferred embodiment that illustrates the best mode now contemplated for putting the disclosure into practice is described herein by, and with reference to, the annexed drawings that form a part of the specification. The exemplary embodiment is described in detail without attempting to describe all of the various forms and modifications in which the disclosure might be embodied. As such, the embodiments described herein are illustrative, and as will become apparent to those skilled in the arts, may be modified in numerous ways within the scope and spirit of the disclosure.
Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims. To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term by limited, by implication or otherwise, to that single meaning.
Various embodiments of the present disclosure are described herein and as depicted in the drawings. It is expressly understood that although the figures depict pullboxes, knockout sections, and/or reinforcement mesh, the present disclosure is not limited to these embodiments. Additional information about the present disclosure can be found in the attached Appendix, which is incorporated by reference in its entirety.
Now referring to
Now referring to
With the reduced thickness in the region of the knockout sections 30a-30c, less effort is needed to create apertures to receive conduits or other similar structures. In addition, creating apertures in the knockout sections 30a-30c preserves the integrity of the overall pullbox 12 and pullbox system 10 as defects such as cracks cannot propagate easily from the knockout sections 30a-30c to other portions of the sidewall 14. Also shown in
While embodiments of the pullbox 12 are described as precast concrete, it will be appreciated that the pullbox 12 can be made from any type of material alone or in combination with other materials such as fiberglass, plastic, etc.
Now referring to
The taper surface 40 has a shape that allows for an easier release from a mold as described in further detail below with respect to a manufacturing process. The taper surface 40 as shown in
However it will be appreciated that in various embodiments, the arcuate portions can have non-constant curvature, non-continuous curvature, a disjointed shape such as a polygonal shape, etc. Further still, in some embodiments, the bottom portion can simply have two flat portion that taper from a side of the knockout portion to a center of the knockout portion.
Now referring to
Now referring to
Each knockout section 30a-30d extends around a portion 58 of the perimeter of the sidewall of the pullbox 12, and non-knockout sections of the sidewall extend around a larger portion 60. The non-knockout sections of the sidewall have a larger thickness than the knockout sections 30a-30d as described above, and thus, the structural integrity of the pullbox 12 is retained, even with the knockout sections 30a-30d extending into the sidewall and even with apertures extending through the knockout sections 30a-30d themselves. Also shown in
Referring now to
Referring now to
When an aperture is created in the knockout section 30b, the user can position the aperture in a space between the members of the reinforcement mesh 62. As shown in
In yet further embodiments, the mold described elsewhere herein can have a protrusion or depression that creates a corresponding depression or protrusion on the knockout portion 30b that indicates the location of the reinforcement mesh 62. Thus, the resulting knockout portion 30b can have a grid like series of depressions and/or protrusions, and a user can create an aperture between the depression and/or protrusions to create an aperture between members of the reinforcement mesh 62.
Referring now to
Referring now to
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Referring now to
The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limiting of the disclosure to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments described and shown in the figures were chosen and described in order to best explain the principles of the disclosure, the practical application, and to enable those of ordinary skill in the art to understand the disclosure.
While various embodiments of the present disclosure have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. Moreover, references made herein to “the present disclosure” or aspects thereof should be understood to mean certain embodiments of the present disclosure and should not necessarily be construed as limiting all embodiments to a particular description. It is to be expressly understood that such modifications and alterations are within the scope and spirit of the present disclosure, as set forth in the following claims.
This U.S. Non-Provisional Application claims the benefit of priority from U.S. Provisional Patent Application Ser. No. 63/120,087 filed Dec. 1, 2020, the entire disclosure of which is hereby incorporated by reference.
Number | Date | Country | |
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63120087 | Dec 2020 | US |