Encapsulated manhole cover

Abstract

Embodiments of the present invention relate to a cover for a manhole or similar structure that encapsulates a traditional cover so as to extend the height of the cover. Generally, a conventional manhole cover is partially or entirely encapsulated in polyurethane to change its outside dimensions to match the environment of an intended location.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a manhole cover and, more particularly to an encapsulated manhole cover.

2. Description of Related Art

In many urban areas the benefits of underground utilities require numerous manholes and other openings to be provided on the streets and sidewalks. While the manhole and its opening are initially almost unnoticeable, the changing surfaces and environment usually reveal the manholes and other gratings after some time.

For example, FIG. 1 illustrates a conventional manhole cover arrangement. An opening 100 is protected by a manhole cover 102 that sits on a circular collar 104 that is generally the same height as a road 106 or other above-ground surface. The design of the collar 104 and cover 102 ensures that the entire arrangement is generally smooth. For example, in the roadway environment, the intention is for a vehicle to be able to pass over the cover 102 with the vehicle's passengers and cargo barely affected.

Over time, however, the road 106 may be re-paved such that its surface rises far above that of the collar 104. When this occurs, traveling over the manhole cover can become very uncomfortable and potentially unsafe because it can damage vehicles or cause drivers to try to avoid them. Municipalities can sometimes be held liable for damage caused by the “potholes” of sunken manhole covers

There have been attempts in the past to address this issue but they have proven time consuming and expensive. For example, one solution is to extend the collars 104 in some manner such as with supplementary collars or extension rings to raise the height of the manhole cover; but this is labor and time intensive as well as expensive. Thus, there exists the need for a way to accommodate the changing elevation of the environment surrounding a manhole cover that can be accomplished without expensive and time consuming construction.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention relate to a cover for a manhole or similar structure that encapsulates or partially encapsulates an existing cover so as to extend the height of the cover. Generally, a conventional manhole cover is partially or entirely encapsulated in polyurethane to change its outside dimensions to match the environment of an intended location.

It is understood that other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein it is shown and described only various embodiments of the invention by way of illustration. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF DRAWINGS

Various aspects of an encapsulated manhole cover are illustrated by way of example, and not by way of limitation, in the accompanying drawings, wherein:

FIG. 1 shows a side view of a conventional manhole cover;

FIG. 2 shows a side view of an encapsulated manhole cover in accordance with the principles of the present invention;

FIG. 3 shows a side cut-away view of the manhole cover of FIG. 2;

FIG. 4 shows an exploded view of a manufacturing method for a manhole cover in accordance with the principles of the present invention;

FIG. 5 shows a bottom view of the system of FIG. 5;

FIG. 6 shows another encapsulated manhole cover in accordance with the principles of the present invention;

FIG. 7 shows yet another encapsulated manhole cover in accordance with the principles of the present invention;

FIG. 8 shows a manhole cover capable of being encapsulated in accordance with the principles of the present invention;

FIG. 9 shows a side-by-side view of different encapsulated manhole covers;

FIG. 10 shows a gasket arrangement useful in cooperation with encapsulated manhole covers in accordance with the principles of the present invention; and

FIG. 11 shows another gasket arrangement useful in cooperation with encapsulated manhole covers in accordance with the principles of the present invention.

DETAILED DESCRIPTION OF INVENTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the invention.

As used herein, the phrase manhole cover is meant to encompass a wide variety of covers that are used to cover subterranean openings. These include manholes to access sewers or other utilities occurring in any location. Such openings can particularly occur on a sidewalk or on a roadway where there is vehicle or pedestrian traffic. Additionally, not all such openings are man-sized yet the phrase “manhole cover” is still used. In some locations, the manhole covers are not always circular but can also be square or rectangular. Furthermore, conventional manhole covers sometimes are solid and sometimes have openings so that they are “perforated”. All such similar devices are meant to be encompassed by the phrase “manhole cover” as used herein. Also, the term “encapsulate” is used to encompass both total encapsulation as well as partial encapsulation of a manhole cover which acts as a substrate. As described below, some embodiments contemplate entirely encasing the manhole cover in a material and other embodiments contemplate less than entire encapsulation.

FIG. 2 illustrates a typical urban environment in which a roadway 206 has been built up to be far higher than the original collar 104 for a manhole cover. Thus, if a conventional manhole cover were in place, its top surface would lie far below that of the roadway 206. Most municipalities have some type of guidelines in place which define an acceptable difference between the height of the roadway 206 and that of the manhole cover 202. For example, in some cities, the allowable difference is merely ⅛ inch. The collar 104 generally refers to a base structure on which the cover 202 rests and may encompass a frame and/or a riser ring.

Embodiments of the present invention contemplate encapsulating a conventional manhole cover in a durable material such as polyurethane so as to add material to the top of the cover so that it's height (or thickness) is increased. Although polyurethane is mentioned as an exemplary material in which to encapsulate a manhole cover, one of ordinary skill will recognize that other materials, such as plastics or polymers, may be selected based on the expected environment (e.g., sunlight, temperatures, road chemicals, exposure to oil, gasoline, and diesel, subject to the weight of various vehicles and potentially struck by snowplows and other equipment.)

As shown in FIG. 2, the encapsulated manhole cover is sized to fit over a collar 104 that was originally in place to support a conventional manhole cover. In this example, the cover 202 is circular and, therefore, has an outside circumference matching that of the collar 104. One benefit of this arrangement is that the encapsulated manhole cover 202 will have at least two horizontal seating areas 208, 210 and a vertical sidewall at which it contacts the collar 104 so as to provide stability, to prevent rotation, and to improve its seal. However, contact at both seating areas 208, 210 is not a requirement to practice some embodiments of the present invention. Additionally, the edge or corner 201 may be beveled or chamfered, unlike the square corner shown in the figure, to provide a smoother transition with the roadway 206.

The height of the encapsulated manhole cover 202 is determined based on the environment in which it is to be located. For example, in FIG. 2, two different heights are possible 212 and 214 because the grade of the roadway 206. Although not shown in the figure, four different measuring points (e.g., every 90 degrees around a circle) would provide four different height measurements for the encapsulated manhole cover. Thus, if thought of as a compass, the height of the encapsulated manhole cover 202 can vary from one height to another in an East-West direction and a North-South direction, respectively.

Thus, one exemplary step of forming the manhole cover 202 of FIG. 2 may involve a person measuring the height of the roadway 206 at various points around the manhole cover. A convenient reference point for such measurements would be a point on the collar 104 which likely was installed level and stable. These measurements can then be recreated in a manufacturing step so that the manhole cover is created with the appropriate contour to match the grade of the surrounding roadway 206. Alternatively, mass manufacturing of “standard” heights could be undertaken so that a user could, for example, procure covers with the closest “standard” height but which are not further customized to their exact location. Although, it is feasible to place a “standard” height cover in place and then grind the surface down to more closely match the surrounding grade.

In the example above, four different measurement points were used but one of ordinary skill will recognize that fewer or more measurement points can be used. Fewer measurements mean that the cover will not match the roadway as accurately while more measurements improve accuracy but add time and complexity to manufacturing. Thus, four measurement points provide a fair balance between complexity and accuracy.

The resulting encapsulated manhole cover 202 will therefore be properly seated only when it is oriented so that the proper height areas are located adjacent to the correct areas of the roadway 206. To aid an installer, the initial measurer may make note of a reference point (e.g., magnetic North) and the manufacturing step can impart a reference mark on the cover 202 that aligns with that reference point that was measured. In this manner, the cover can be properly aligned when installed.

FIG. 3 shows a detailed view of an exemplary encapsulated manhole cover designed in accordance with the principles of the present invention. A cover 300 is encapsulated between an upper region 302 and a bottom region 304 of polyurethane. Although these regions 302, 304 are referred to separately, they are physically all part of the same homogenous structure that surrounds the cover 300. The cover 300 also includes one or more holes 306 that allow the polyurethane to bridge from the upper region 302 to the bottom region 304. These holes 306 can be arranged in any type of pattern but are sufficient to create a structure that will not de-laminate under the stress of the roadway environment. Although the holes 306 are depicted as having relatively straight side walls, these walls can be sloped as well or otherwise shaped to enhance the adherence of the encapsulating material to the cover 300. The cover 300 is traditionally constructed of metal by a foundry but other strong synthetic materials have recently been used in constructing manhole covers and embodiments of the present invention will work with either type of material.

A pick-hole 310 is typically present, but not always necessary, in a manhole cover to aid in its removal from the ground. During the forming process of the encapsulating upper region 302, an opening 308 can be formed to provide access to the existing pick-hole 310. This opening 308 may beneficially have a flexible flap that prevents debris from entering the opening 308 while still allowing access by a tool to the pick-hole 310. Manhole covers having through-holes are not usually constructed with pick holes but because embodiments of the present invention encapsulate the cover (thus making the through-holes inaccessible) a pick hole can be specially constructed in the cover even though it already has through-holes.

FIG. 4 illustrates the principles of manufacturing an encapsulated manhole cover according to embodiments described herein. However, many varied ways to mold polyurethane are known and can be accomplished with various techniques, temperatures, recipes, etc. The present discussion of manufacturing is merely to provide a description of those aspects of the encapsulated manholes covers that can be controlled during manufacturing.

In FIG. 4, for reference, the cover 300 is flipped so that its top is pointed down. A mold piece 404 is placed on the cover 300 which rests above another mold piece 402 at a height that determines the thickness of the region 302 (See FIG. 3). A liquid polyurethane precursor would be added to the mold and then cured to form the final encapsulated cover. Through the use of customized molds, the top appearance of the encapsulated cover can be customized in appearance. Also, because polyurethane adheres well to itself, the molding process can be performed in multiple steps so that different colors can be used to even further customize the appearance of the cover. For example, a multicolored layer can be applied on top or multiple single color layers (or a mix of the two) such that a subsequent CNC milling step can customize the design, color, and appearance of the visible surface of the end product. To improve the adherence of the polyurethane to the metal manhole cover, techniques and chemicals are known that etch and coat the metal to strengthen the bonding between the two materials

A support structure 406 supports the mold 402 and has a variety of adjustable legs 408, 410, 412. This support structure can be seen in FIG. 5 with four different adjustment points 408, 410, 412, 414. These adjustment points can be selected to correspond to the four measurements taken on site at the intended location. As a result, the encapsulated cover 202 will have a top surface whose height can vary in at least two degrees of freedom. Because polyurethane and similar materials are relatively easy to mill, an alternative manufacturing method would be to mold the encapsulated covers to generally the same height (or a set of standard heights) and then customize the height for each cover based on its intended location through a CNC milling operation.

FIG. 6 illustrates additional features of embodiments of the present invention. For example, batteries or other electronics 606 can be attached to the bottom of the cover 202. This location will be a relatively dry and safe location so that even sensitive equipment may be located within a manhole. Other electronic devices 604, either active or passive, can be encapsulated within polyurethane near the conventional manhole cover. This location protects the electronics 604 from the environment but offers less interference than if the manhole cover was metal and the electronics were located below as previously discussed. There are also items 602 that can be embedded near the surface of the encapsulated manhole cover 202. For example, an identification plate can be embedded so that each cover has a serial number or other identifying information visible to an observer or an electronic reader. Also, a compass could be embedded which an installer could use, along with an appropriate reference arrow on the cover, to properly align the cover whenever it is being put back into place.

One of ordinary skill will recognize that a wide variety of items (602, 604, 606) can be attached to a manhole cover in this way. Passive or active RFID tags can be used. GPS location information as well as other telemetry data can be captured by computerized equipment. For example, the electronics 606 can measure temperature or other environmental conditions within the manhole and communicate them to other electronics 604 that broadcasts them or stores them for later retrieval.

Using ID information (e.g., serial number, ID tags, etc.) a municipality can maintain a database that indicates what is intended to be underneath each manhole. Thus, a utility worker arriving at a site that has numerous manhole covers can scan for the appropriate RFID identifier to locate a desired opening. The sensors 604 can measure road conditions, environment conditions, traffic volumes. Also, through the use of accelerometers or GPS devices, the location and movement of manhole covers can be tracked.

Additionally, during the manufacturing, the mold can be shaped so as to form one or more beads 608 around the circumference of the encapsulated manhole cover 202. These beads will act as a gasket inside the collar and thus augment the sealing capability of the encapsulated manhole cover as well as further reduce the likelihood that the cover will rotate.

FIG. 7 shows an encapsulated manhole cover in which the original cover 700 is not entirely encapsulated as in previously described embodiments. In this embodiment, the cover is manufactured in a way that results in the polyurethane layer 702 encapsulating only the top surface of the cover 700 and extending slightly at a region 704 into the through-holes 706. Typically, the depth of the extension region 704 in each through-hole may be as little as ⅛ to ¼ of an inch and still provide sufficient strength to help maintain the bond between the polyurethane layer 702 and the cover 700. One of ordinary skill will recognize that the depth of one extension region 704 does not have to equal that of an extension region 704 of a different through-hole. Also, some through-holes may be partially filled or fully filled while others merely have an extension region 704 around its inside periphery. One of ordinary skill will also recognize that removable plugs may be used in one or more of the through-holes during manufacture so that not every through-hole has an extension region 704. For example, using such plugs in half the through-holes will further reduce an amount of polyurethane consumed but not adversely impact the bonding strength between the cover 700 and the polyurethane 702.

The partially encapsulated manhole cover 710 of FIG. 7 uses significantly less polyurethane than a similar cover 202 shown in FIG. 2 and yet accomplishes the same effect of extending the height of the top of a conventional manhole cover. Also, the additional devices and electronics described with respect to FIG. 6 can be utilized as well.

An additional method to conserve polyurethane is to use a non-conventionally shaped manhole cover that is specially designed for embodiments of the present invention. The manhole cover 802 can be constructed of conventional materials and have conventional through-holes 804 but, as can be seen from this cross-sectional view of FIG. 8, also include unconventional features such as two seats 806, 808 and an arched region 810. This unconventional manhole cover 802 can be fully encapsulated in polyurethane or can be partially encapsulated in polyurethane as is shown in FIG. 7 as long as a profile shape is maintained that appropriately mates with the collar in which the resulting cover will ultimately sit.

The right side of FIG. 9 shows the unconventional cover 802 partially encapsulated with polyurethane 902 and seated on the collar 104. The left side shows a conventional cover 300 fully encapsulated with polyurethane 302 also sitting on a collar. As can be seen, the roadway, or outside level, 904 is significantly higher than the top of the collar 104. The thickness of polyurethane needed to bring each encapsulated manhole cover up to the level 904 is different in each case. Because of the two seating surfaces 806, 808 of the unconventional cover 802, it sits higher on the collar 104 and only requires a thickness B of polyurethane. The other embodiment with conventional cover 300 requires a thickness A of polyurethane where A is greater than B.

In the fully encapsulated cover of FIG. 2, the polyurethane at different locations around the edge of the encapsulated cover provided an anti-rotation effect as well as helped create a tight seal with a collar. When a cover is partially encapsulated, as in FIG. 7, additional gaskets may be useful to provide similar benefits, or a cover 710 may be inserted in an opening after a bead of butyl mastic or other sealant has been applied to one or both surfaces that will contact one another.

FIGS. 10 and 11 illustrate various gasket configurations useful with the unconventional cover 802 of FIG. 8. One of ordinary skill will readily recognize that a similar, but single, gasket arrangement can also be used for the conventional, partially encapsulated cover 710 of FIG. 7 without departing from the scope of the present invention. The partial, cut-away views of these figures show only a cross-section of various gaskets but it is contemplated that the illustrated gasket would extend around the periphery of the manhole cover 802 or manhole collar 104. FIG. 10 shows a gasket location 1002 at one of the seating areas of the unconventional manhole cover of FIG. 8 and a second gasket location 1004 at the other seating area. Although two gaskets are shown at each location, fewer or even more gaskets could be used as well. Additional gaskets may be used or thicker gaskets may be used to raise the height of the entire encapsulated cover so that even less polyurethane 902 is needed on top of the encapsulated cover in order to match the surrounding surface 1006. FIG. 11 shows a gasket 1100 having an “Z”-shaped cross section. The thickness 1102 and 1104 should be approximately equal but the size of the vertical region 1106 can vary so as to match the physical constraints of the intended location which may vary. As for material, the gasket is beneficially constructed of urethane, a polymer, rubber, or similar material.

The previous description is provided to enable any person skilled in the art to practice the various embodiments described herein. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments. Thus, the claims are not intended to be limited to the embodiments shown herein, but are to be accorded the full scope consistent with each claim's language, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” All structural and functional equivalents to the elements of the various embodiments described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.”

Claims

1. An encapsulated manhole cover comprising:

an upper region made of a first material;

a substrate, having one or more through-holes, made of a second material; and

a respective extension region located within at least some of the one or more through-holes and made of the first material and integrally formed with the upper region;

wherein the upper region and the respective extension region encapsulate at least a portion of the substrate.

2. The encapsulated manhole cover of claim 1, wherein the respective extension region extends about one-eight to one-fourth an inch into a particular one of the one or more through-holes.

3. The encapsulated manhole cover of claim 1, further comprising:

a bottom region made of the first material; and

a respective bridging region made of the first material located within at least some of the one or more through-holes and integrally formed with the upper region and bottom region,

wherein the upper region, respective bridging region, and bottom region encapsulate the substrate.

4. The encapsulated manhole cover of claim 1, wherein the first material is different than the second material.

5. The encapsulated manhole cover of claim 1, wherein the substrate is a conventional manhole cover.

6. The encapsulated manhole cover of claim 5, wherein the second material comprises iron.

7. The encapsulated manhole cover of claim 5, wherein the second material comprises a composite polymer.

8. The encapsulated manhole cover of claim 1, wherein the first material comprises polyurethane.

9. The encapsulated manhole cover of claim 1, wherein an exposed surface of the upper region is customizable in design.

10. The encapsulated manhole cover of claim 1, wherein an exposed surface of the upper region is customizable in color.

11. The encapsulate manhole cover of claim 1, wherein a height of the upper region varies from a first height to a different second height along a first direction.

12. The encapsulated manhole cover of claim 11, wherein the height of the upper region varies from a third height to a fourth height along a second direction orthogonal to the first direction.

13. The encapsulated manhole cover of claim 1, wherein one or more electronic devices are encapsulated in at least one of the upper region and the bottom region.

14. A method of making an encapsulated manhole cover comprising the steps of:

creating a mold comprising: a top region adjacent a top of a substrate having one or more through-holes;

curing polyurethane within the mold so as to encapsulate at least the top of the substrate such that a respective extension region of polyurethane extends at least partially into at least some of the one or more through-holes.

15. The method of claim 14, wherein:

the mold further comprises: a bottom region adjacent a bottom of the substrate; and

the step of curing includes curing polyurethane within the top and bottom regions of the mold so as to fill at least some of the through-holes and encapsulate the substrate with polyurethane.

16. The method of claim 14, wherein the substrate is a conventional manhole cover.

17. The method of claim 14 further comprising the step of:

adjusting the top region so that a distance of an inner surface adjacent the top of the substrate varies at different points with respect to the top surface.

18. The method of claim 17, wherein first, second, third and fourth points at the periphery of the inner surface have different heights with respect to the top surface.

19. The method of claim 18, wherein a first line connecting the first and second points has a direction orthogonal to a second line connecting the third and fourth points.

20. An encapsulated manhole cover comprising:

a substrate having a plurality of through-holes; and

an encapsulating layer surrounding at least a top surface of the substrate and at least partially filling at least some of the through-holes.

21. The encapsulated manhole cover of claim 20, wherein the encapsulating layer surrounds the substrate and fills each of the plurality of through holes.

22. The encapsulated manhole cover of claim 20, wherein the substrate comprises a conventional manhole cover.

23. The encapsulated manhole cover of claim 20, wherein the encapsulating layer comprises polyurethane.

24. The encapsulated manhole cover of claim 20, wherein a thickness of the encapsulated manhole cover varies from a first height to a different second height along a first direction and from a third height to a fourth height along a second direction orthogonal to the first direction.