Modular Utility Vault

Abstract

A modular construction for underground utility vault. Semi-cylindrical end sections are molded in the form of a relatively thin shell from fiberglass or other moldable material of similar physical characteristics. The shells are formed with a series of radially offset circumferentially extending ribs which provide increased rigidity to the shell and also form shelves for supporting elements such as transformers, connection points, etc. within the vault. The end section is one form of structural module which may, in some installations, be combined with a second modular element in the form of a flat side panel having a cross-sectional configuration matching that of the end section. Two end sections may be secured to each other to form a cylindrical vault or, alternatively, two end sections may be assembled with one or more pairs of side panels attached to and mounted between the opposed end sections. A cover element of laminated molded sheet material closes the opening at the upper end of the completed vault and is provided with internal stiffening ribs. A lock and retainer-hinge assembly is employed to releasably lock the cover in position and enables the cover, when unlocked, to either be swung upwardly as on a hinged mounting or removed entirely.

Description

BACKGROUND OF THE INVENTION

In recent years, there has been a substantially increased use of underground or buried systems for supplying electricity and telephone connections particularly in residential areas. Underground systems of this type require the use of junction points or connection boxes where various branch lines are brought together and/or connected into the main distribution system. To achieve full realization of all of the advantages of an underground system, many forms of underground vaults have been employed. In their most usual form, such vaults are constructed either from poured concrete or from metal, usually in the form of galvanized corrugated sheet metal.

The obvious disadvantage of a vault of metallic construction employed underground is that sooner or later the metal will rust and corrode. Further, when a metal vault is employed in an underground electrical or telephone distribution system, care must be taken to make sure that the vault wall is electrically insulated from the current-carrying portions of the distribution system.

While concrete vaults avoid the rust and corrosion problems of steel vaults, they suffer a serious drawback from the standpoint of weight and non-machinability. The weight of a concrete vault, even when broken down into several sections, is usually such as to require the use of power-driven hoisting equipment during its installation. Further, when it is desired to bring additional lines into a concrete vault, the only way this can be accomplished is by knocking a hole through the side of the vault, which can be extremely difficult and complicated by existing equipment already mounted in the vault.

While a concrete vault does not rust or corrode, metal parts which come in contact with the concrete are, by their very contact, extremely susceptible to rust and corrosion, as well as to electrolytic action.

SUMMARY OF THE INVENTION

The present invention is designed to overcome the problems outlined above in connection with the use of steel or concrete vault structures. A vault constructed in accordance with the present invention is assembled from standardized units formed of relatively thin, and hence lightweight, molded plastic material. Preferably the material employed is fiberglass, although there are many other commercially available plastic materials having physical characteristics quite similar to those of fiberglass. In addition to being resistant to rust, corrosion and chemical and electrolytic reactions with metal parts in contact with the fiberglass, the structural characteristics of fiberglass are such that individual modular elements having adequate structural rigidity can be formed in reasonably thin-walled sections so that the individual modular elements can easily be handled manually. Further, the fiberglass shells can be readily pierced by a conventional drill or hole saw to provide cable entrances and exits at desired locations and also to enable elements of the distribution system to be mounted upon and attached to the fiberglass shell.

One form of modular unit consists of a semi-cylindrical shell or end section which is of generally uniform wall thickness and formed with a plurality of radially offset ribs. The ribs enhance the structural rigidity of the shell and further provide shelves at the interior of the vault to support various elements of the distribution system. Two end sections may be bolted together to form a cylindrical vault, or pairs of generally flat side panels having a cross-sectional shape matching that of the end sections can be attached between two end sections to form a vault of larger dimensions. A cover of a laminated fiberglass sheet construction is employed to close the upper end of the vault and is provided with a series of integral internal ribs for structural strength. The top of the cover is provided with a recess into which passes a padlock hasp secured to the top of the shell wall at one side of the shell. At the opposite side of the vault, one or more bolts, mounted in the top of the shell wall pass inwardly through openings in the cover to provide a retainer-hinge assembly. The various elements are described in grater detail below.

IN THE DRAWINGS

FIG. 1 is an exploded perspective view showing various elements of a modular utility vault embodying the present invention;

FIG. 2 is a vertical cross-sectional view of a typical vault installation embodying the present invention;

FIG. 3 is a side elevational view of a modified form of installation, with certain parts broken away and shown in section;

FIG. 4 is a top plan view of the installation of FIG. 1 with the cover removed;

FIG. 5 is a top plan view of the cover of the installation of FIG. 3;

FIG. 6 is a detail cross-sectional view showing details of the cover lock; and

FIG. 7 is a detail cross-sectional view of the cover retainer-hinge.

Referring first to FIG. 1, there are disclosed various modular units employed in the practice of the present invention. These units include a generally semi-cylindrical end section designated generally 10, a side panel 12 and a cover 14. Depending upon the requirements of the particular installation, an installation may consist simply of two end sections 10 secured to each other to form a generally cylindrical vault, in which case a circular cover such as 14 would be employed. In other cases, where a larger vault is required, the end sections 10 may be spaced from each other by one or more pairs of side sections 12 as in the embodiment of FIGS. 3 and 4, in which case a modified form of cover 16 such as that disclosed in FIG. 5 would be employed.

End sections 10 and side panels 12 are molded from synthetic plastic materials, such as fiberglass. Desirable characteristics of the actual material employed are that it be electrically non-conductive, that it be resistant to corrosion, non-electrolytic, and that is possesses reasonable capabilities for being cut or machined. In addition, the physical characteristics of the material should be such that in its molded form it possesses a relatively high strength-to-weight ratio. Fiberglass has been found to adequately satisfy all of these conditions and is a preferred material for the present invention, however, many of the synthetic thermoplastic materials presently commercially available will be found to be adequate for the present purposes.

Referring now particularly to FIGS. 1 and 2, end sections 10 are of one-piece molded construction in the form of a relatively thin, generally semi-cylindrical shell. In the particular embodiment disclosed, the shell is formed with three radially offset ribs 18, 20, and 22. As best seen in the cross-sectional view of FIG. 2, the three ribs are of identical configuration, each having an inwardly inclined lower wall 18a, 20a, 22a respectively. The ribs extend circumferentially of end section 10, and the upper walls 18b, 20b and 22b all lie in general planes which extend radially of the axis of the semi-cylindrical shell which defines the end section 10.

At the lower end of each end section 10, an outwardly projecting radial flange 24 is integrally formed, and radially outwardly projecting side flanges extend along the axial edges of the shell. Flanges 26 are formed with a series of bolt receiving openings 28 which enable two end sections 10 to be fixedly secured to each other with the flanges 26 of the respective end sections 10 clamped in face-to-face engagement with each other.

Referring briefly to FIG. 1, the vertical cross-sectional configuration of side sections 12 is identical to that of end sections 10, the side panels 12 being formed with three offset ribs 30, 32 and 34 corresponding to and of identical cross-sectional configuration to the ribs 18, 20 and 22 respectively. Like end sections 10, side sections 12 are formed with a horizontal flange 36 extending along its lower edge, and with vertically extending outwardly projecting side flanges 38 along each vertical edge, the side flanges being provided with bolt receiving openings 40 as was the case with the flanges 26 of end section 10.

Ribs 18, 20 and 22 and flanges 24 and 26 serve to increase the structural rigidity of the semi-cylindrical end sections, thus enabling the shell, which is of uniform thickness throughout, to achieve adequate structural rigidity with a relatively thin wall thickness, hence resulting in a completed shell of light weight. Where the material employed is fiberglass, a shell of adequate strength having overall dimensions of approximately six feet in length and three feet in diameter can be constructed with a wall thickness of between three-eighths and one-half inch. A shell of these dimensions is light enough to be easily handled by one man.

Referring now to FIG. 2, there is shown, in vertical cross section, a typical installation wherein two end sections 12 are secured to each other to form a cylindrical underground vault.

As is apparent from FIG. 2, ribs 18, 20 and 22 not only function as stiffeners for the shell structure, but also provide internal shelves for mounting and supporting equipment within the interior of the vault. In the installation of FIG. 2, the upper walls 22b of the lowermost rib 22 serve as a support for a support frame 42 upon which is in turn supported an electrical transformer 44. Support frame 42 may be of any suitable construction. In FIG. 2 it takes the form of a simple X-shaped frame constructed from U-shaped channel members. An X frame of this type may also be employed in rigidifying the assembled structure by resisting horizontal forces directed inwardly of the shell structure. The transformer is held in position by means of a U-shaped metal bracket 46 bolted to the transformer casing as at 48 and to the wall of one of the end sections 10 as by bolts 50. The properties of the fiberglass shell are such that it can be easily pierced by a drill or hole saw so that structural elements such as bracket 46 can be located to suit the convenience of the particular installation in the field and holes through the wall of the shell, such as 50 for the passage of electric power cables such as 52 into and out of the shell, can easily be made at the desired location.

In the installation of FIG. 2, an electric junction point 54 is supported upon the upper wall or shell of rib 20, and held in position by bolts 56 passing through the shell wall.

The upper wall of rib 18 is employed as a closure cover seat to support cover 14. Cover 14 is preferably of two-piece construction and includes an upper lid 58 and a lower member 60 which is preferably formed with one or more diametrically extending ribs 62. The upper edges of rib 62 are flush with the upper edge of an upstanding peripheral flange 64 formed as an integral part of member 60, and the flat bottom surface of lid 58 is permanently bonded to the upper edges of flange 64 and rib 62. The purpose of ribs 62 is to rigidify the cover. As indicated in FIG. 2, the top edge of end section shells 10 are buried flush with the surface of the ground so that cover 14 is likewise flush with the ground surface. Cover 14 thus must possess sufficient rigidity to enable persons to walk across the top of the cover.

Cover 14 is releasably locked in its assembled position by a lock structure designated generally 68 and a retainer-hinge arrangement designated generally 70. Details of lock assembly 68 and retainer-hinge assembly 70 are best seen in FIGS. 6 and 7.

Referring first to FIG. 6, the lock assembly includes a U-shaped hasp 72 which is fixedly mounted on upper wall 18b of rib 18 by a pair of nuts threadably received on each of the two legs of hasp 72 above and below wall 18b. Cover lid 58 is formed with an indented recess 76 and, when the cover is in position, hasp 72 projects upwardly into recess 76 through suitably located openings 78 and 80 in lower member 60 and in the bottom of recess 76 respectively. Peripheral flange 64 of lower member 60 is formed with a recess 82 complimentary in shape to recess 76. Recess 76 is dimensioned to receive a conventional padlock 84 which is passed through hasp 72 to lock to cover in position.

The cover is retained on the seat defined by upper wall 18b at its opposite side by a bolt 84 (FIG. 7) fixedly mounted to the upper portion of a shell 10 above upper wall 18b as by a nut. A bore 88 through peripheral flange 64, having a diameter somewhat larger than that of bolt 84 receives the bolt when the cover is assembled.

When the padlock at the diametrically opposite side of cover 14 from opening 88 is unlocked and disengaged, the enlarged bore 88 permits the cover to be swung upwardly, as if bolt 84 were a hinge to permit a cursory inspection of the interior of the vault. If it is desired to completely remove the cover, the elevated cover is simply pulled free from bolt 84 and removed.

It will be noted that the mounting of the junction point upon the shelf defined by rib 20 near the top of the vault makes the connections of the junction point readily accessible, once cover 14 has been removed. This is of extreme convenience in the event it is necessary to disconnect or break the circuit at the junction point since the junction point can easily be reached from the exterior of the vault. Because the fiberglass shell can be readily drilled, the junction point can be located at any desired point around the periphery of the vault and it is a simple matter to install additional junction points or other units as required.

In FIGS. 3 through 5, a modified form of vault is disclosed which includes a pair of end sections 10 and a pair of side panels 12 installed between the two end sections to result in an elongated oval type vault, as compared to the cylindrical construction of the FIG. 2 embodiment. The side flanges 38 of side panels 12 are bolted to the corresponding flanges 26 of the respective end sections, the ribs 30, 32 and 34 of the side panels forming continuations of the corresponding ribs 18, 20 and 22 of the end sections.

The embodiment of FIG. 3 necessarily employs a different cover configuration which, because of its enlarged area is provided with a somewhat more extensive system of internal ribs 90. Apart from its overall shape and arrangement of internal ribs, the cover 16 is similar to cover 14. Because of its shape, two or more retainer-hinges 70a are employed at spaced points along one of the two side panels 12 in combination with a single lock assembly 68a. Lock assembly 68a and the individual retainer-hinge assemblies 70a are of the same construction respectively as the lock assembly 68 and the retainer-hinge 70 of the FIG. 2 embodiment.

In an arrangement such as the FIG. 3 embodiment, where one or more pairs of side panels 12 are employed, it may be desirable to provide some transverse bracing between the opposed side panels. This may be accomplished by employing a platform-like member 92 as a support member for mounting on the lowermost of the three shelves, supplemented, if necessary, by an H-shaped bracing member 94 at the intermediate shelf. The inward pressure exerted by the soil against the vault walls depends, to a large extent, on the characteristics of the soil and in many installations, transverse cross-bracing of the type provided by platform 92 or brace 94 is not necessary. In the cylindrical embodiment of FIG. 2, the cylindrical configuration of the completed vault is quite stiff against radially directed forces, but transverse bracing may be required in those installations where flat side panels 12 are employed. It is only necessary that the vault function to, in effect, maintain an underground chamber, and hence a slight deflection of the vault walls is usually acceptable.

The resulting vault shape of FIGS. 3 and 4 is particularly advantageous for installations that are to enclose both a transformer and switching units or junction points. In a 220-110 volt system, for example, the transformer may be centrally located on platform 92 with the neutral junction units placed on the available shelf just above the transformer in a central position below hasp 72. The pair of high-voltage junction units are then placed on the same shelf individually near respective opposite ends of the vault. The three different electrical circuits thus are well separated, while, at the same time, the junction units of each are readily available near the top of the vault so that an operator can actuate any or all of them from an external, safe position.

The invention contemplates use of the modular approach for the formation of vaults having overall shapes, in plan view, different from that illustrated thus, the cylindrical end shells may be modified so that polygonal forms result, and various other combinations may be constructed, including those that are rectangular or L-shaped. Generally speaking, however, it is preferred to utilize curved surfaces as much as possible in order to gain structural strength.

In normal circumstances, the bottom of the vault is left open to permit free drainage of any surface water which may find its way into the interior of the vault. If, however, it is desired to seal the bottom of the vault, this may be done simply by bonding a cover of appropriate shape in position at the vault bottom. In view of the fact that the openings through which the various cables pass through the vault walls are not usually provided with weather-tight fittings and the fact that no water-tight seal is provided between the cover and vault walls, the usual practice is to leave the vault bottom open.

Claims

Having described two exemplary embodiments of the invention, I claim:

1. A utility vault comprising a pair of like semicircular sections of a molded plastic material having a high strength-to-weight ratio, such as fiberglass, each of said sections comprising an axially elongate generally semicylindrical shell of relatively thin uniform wall thickness, a plurality of radially offset circumferentially inwardly extending ribs integrally formed in each of said shells, the ribs on the respective shells being axially aligned with each other to extend continuously around the periphery of the tubular vault, each rib having a flat substantially horizontal first wall extending radially inwardly from the semicylindrical shell wall and a frusto-conical second wall integral with and inclined outwardly from the radially inner edge of said first wall to the semi-cylindrical shell wall, the first walls of said ribs being disposed on the upper side of said ribs when said tubular vault is in an upright position, to define a plurality of peripherally extending shelves in the interior of the vault, the uppermost one of said shelves being located in adjacent spaced relationship to the upper end of the vault to constitute a closure seat, said ribs further defining frusto-conical channels in the exterior walls of said shell with the upper wall of said channels being substantially horizontal, means on the vertical edges of each of said sections for securing said sections together to form a tubular vault, and a cover closure comprising an upper and a lower member of sheet plastic material having a high strength-to-weight ratio, such as fiberglass, said lower layer being interconnected to said upper layer and having vertically extending rib sections having a depth substantially equal to the vertical spacing between said upper end of said vault and said uppermost one of said shelves.

2. A vault as defined in claim 1 wherein said securing means includes a pair of like side panels secured to and extending between said semi-circular sections, each of said side panels having a generally flat configuration and having a plurality of offset ribs thereon identically matching the interior and exterior configuration of said ribs on said semi-circular sections and defining a continuation of said interior shelves and said exterior channels.

3. A vault as defined in claim 1 wherein said ribs define at least two shelves in addition to said uppermost one of said shelves, one of said two shelves being located adjacent said uppermost one of said shelves and the other of said two shelves being located adjacent the lower end of said shell.

4. A utility vault as defined in claim 1, wherein said closure cover comprises a generally flat upper lid member, shaped to overlie and project outwardly beyond the upper rim of said tubular vault and said lower lid member is integrally bonded to the lower side of said upper lid member and said rib sections comprise uniformly spaced vertical inner and outer ribs extending substantially around the peripheral area of said lower lid member, with uniformly spaced vertical ribs extending transversely of said lower member between opposite locations on said inner rib.

5. A utility vault as defined in claim 1 including means for locking said cover closure in place to enclose the upper end of the vault, means defining a lock receiving recess in said cover closure having a hasp receiving opening therein, said means for locking including a hasp fixedly secured to said uppermost one of said shelves and projecting upwardly therefrom through said opening, and detachable hinge means on the side of said vault opposite said locking means comprising pin means fixedly secured to at least one of said shells above said uppermost shelf and projecting radially inwardly, and opening means defined in said vertically extending rib section of said cover closure for receiving said pin means to detachably and hingeably couple said cover closure to said shells.

6. In a utility vault designed to be buried in the ground with its uppermost part substantially flush with the ground surface, means on the uppermost part of said vault defining an upward-facing closure seat, a cover for said vault comprising: a generally flat horizontal lid member shaped in conformity with said uppermost part of said vault, a generally flat lower horizontal member spaced below said lid member, each of said members being of fiberglass or the like, a peripheral flange and a plurality of vertical ribs integrally bonding said members to each other, means defining a releasable lock between said walls and said cover, a pin projecting horizontally inwardly of said vault above said seat, and means for defining an opening in said peripheral flange loosely receiving said pin to positively retain said cover on said seat in cooperation with said lock and to accommodate hinging and removal of said cover when said lock is released.