Abstract:
A cover system for septic tanks adapted to be attached to the a septic tank and provide access for repair and maintenance. The assembly includes a base which is embedded into the concrete and provides a seal between the concrete and the base. A pipe member is joined to and sits atop the stationary base member. A wrap made of high density polyethylene surrounds the pipe and covers its corrugations to reduce outside forces upon the pipe. Finally, there is a top cover which is designed to engage the top of the pipe. Additionally, a channel is provided to catch the edge of the pipe and a seal is provided to prevent leakage between the pipe and cover.

Description:
BACKGROUND OF THE INVENTION  
   I. Field of the Invention 
   This invention relates generally to septic tank cover systems, and more particularly to septic tank cover systems which are designed to provide access to septic tanks, seal septic tanks from water, and prevent tank leakage. 
   II. Discussion of the Prior Art 
   It is well known that access to septic tanks buried underground is periodically needed so that material can be pumped from the tank and maintenance performed. It is important for structures which provide access to the tanks to maintain a water tight environment leading to the buried septic system. The seals for these structures are greatly susceptible to leaks due to their exposure to an outdoor conditions. Frost heaving, forces related to vertical ground movement, and rotational forces due to lateral ground movement can each have a potentially detrimental impact on the integrity of septic tank access structures. 
   To improve the longevity and durability of access points to septic tanks, it is desirable, as much as possible, to protect the structure from potentially damaging types of ground forces. Various aspects of these problems have been addressed in some previous disclosures although a design specifically suited to properly address these concerns has never been as fully and effectively designed before. For example, in the Meyers. U.S. patent application Pub. No. 2003/0145527, a riser component for an on-site waste system is described which incorporates a riser pan, a cover, and various interconnecting riser elements. The Airhart U.S. Patent Application Pub. No. 2004/0040221 is directed at a molded manhole unit. This application shows a unit with a manifold riser having a beveled riser edge, a riser extension which mates with the manifold riser, a sealing ring, and a riser cap. 
   The present invention offers important advantages over the prior art due to new concepts included in its design. Specifically, the arrangement of the riser base of the present invention offers several superior features not found in the prior art. These features relate to the ledge and depressions below the ledge that allow secure anchoring of the device into a concrete casting. These advantages also include the uninterrupted surface upon which the pipe member can rest. This surface provides an effective mechanism for sealing the junction between the base and the pipe. The use of corrugated pipe also provides certain advantages in terms of cost, strength, and the ability for one to cut the pipe to length rather than having to buy a specific piece of a specific height. The invention overcomes the problems associated with using such a pipe by providing a novel sealing surface between the pipe and the top cover, a novel sealing arrangement between the riser base and the pipe, and also by providing a sleeve that covers the corrugations in the pipe to prevent the pipe from coming loose from the base due to ground forces. Finally, the manner in which the top cover of the present invention engages the pipe to provide an effective seal that is much more refined and simple than what is shown in the prior art. 
   SUMMARY OF THE INVENTION 
   The present invention provides for a cover system for septic tanks which is adapted to be attached to a septic tank and provide a water tight seal access for pumping the contents of the tank and maintaining the tank. The assembly includes a base member which is embedded into the concrete of an underground septic tank providing a seal between the concrete and the base. A pipe member is joined to and sits atop this stationary base member. A wrap made of high density polyethylene surrounds the pipe and covers its corrugations to reduce outside forces upon the pipe. Additionally, there is a top cover which is designed to engage the top of the pipe. Further, a channel is provided on the base to catch the edge of the pipe, novel seals are provided to prevent leakage between the pipe and cover and between the pipe and base. These features work together to form a stable and water tight structure for closing an access opening to a septic tank. 
   These and other objects, features, and advantages of the present invention will become readily apparent to those skilled in the art through a review of the following detailed description in conjunction with the claims and accompanying drawings in which like numerals in several views refer to the same corresponding parts. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the septic cover assembly of the present invention without the outer wrap member; 
       FIG. 2  is a perspective view of the base member of the septic cover assembly; 
       FIG. 3  is a perspective view of the pipe member of the septic cover assembly; 
       FIG. 4  is a perspective view of the cover member of the septic cover assembly; 
       FIG. 5  is a perspective view of the septic cover assembly without the outer wrap member; and 
       FIG. 6  is a perspective view of the septic cover assembly. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present invention represents broadly applicable improvements for septic tank design to provide an effective sealed means and stable structure for accessing a septic tank. The embodiments herein are intended to be taken as representative of those in which the invention may be incorporated and are not intended to be limiting. 
   Referring first to  FIG. 1 , there is a perspective view of the septic cover assembly shown which would be buried in the ground and cemented in place to provide convenient access to a septic tank from above the ground. The assembly itself is indicated generally by numeral  10  and includes a base  12 , a pipe  14 , a top cover  16 , and a wrap  17  (see  FIG. 6 ). These four components work together to form an invention which create a passageway of structural integrity well-suited for continued and efficient access to a desired septic tank. 
     FIG. 2  discloses a perspective view of the base member  12  of the septic cover assembly allowing for a more detailed examination of its features. Base  12  is a largely cylindrical component which is made of high density polyethylene. It provides a riser coupling which is primarily embedded within concrete and forms a seal between the concrete and the base  12 . The riser coupling has a 24-inch opening providing access to the concrete tank in which the base  12  is embedded. Base  12  is comprised of four annular sections  18 ,  20 ,  22 , and  24 . The first annular section  18  is made up of a cylindrical wall containing a plurality of depressions  26  which fill with concrete that encapsulates section  18  of the base member  12  when concrete is poured around it. This arrangement prevents the base member from rotating in the concrete. 
   Directly above first annular section  18  is a second annular section, ledge  20 . Ledge  20  is an annular protrusion which extends radially outward to achieve a diameter substantially larger than the previous diameter of section  18 . Ledge  20  has an upper lip  28  and a lower lip  30  that diverge from one another as the annular protrusion extends radially outward. Lip  28  and lip  30  are joined by a vertically disposed outer surface  31 . These features prevent the base member from moving up or down with respect to the tank when the ledge  20  is embedded in the concrete. These features of ledge  20  also stiffen the upper structure of the base when the ledge  20  is fully encapsulated by concrete. 
   Juxtaposed directly above ledge  20  is a third annular section  22 . Section  22  has a smaller diameter than ledge  20 . The top rim edge  32  of rim  22  marks the height to which concrete is filled when poured around base  12 . The rim edge  32  is the feature pipe  14  abuts up against when it is slid onto base  12 , as will be later discussed. The edge  32  also assists in providing a water tight seal between the pipe  14  and the base  12 . 
   The last annular section is a riser coupling  24  which has a cylindrical portion  34  of constant diameter and an inwardly projecting lip  36 . This section provides a sturdy projection which mates with and is generally covered by pipe  14 . It also provides a further barrier to the outside environment. 
   Referring now to  FIG. 3 , a section of pipe  14  is shown. Pipe  14  is a 24-inch diameter dual wall pipe. The pipe must extend from the base  12  when it is buried underground to above ground level. Thus, dual wall pipe is used that can be cut to length. The length of pipe is typically cut at the time of installation and is made between the corrugations. Only the length of two corrugations of pipe are shown in  FIG. 3  although various much longer lengths of pipe containing many more corrugations are common. The pipe  14  is designed to be slid over the top of the riser coupling  24  so that the bottom edge  38  of the pipe  14  will come in contact with the concrete filled to rim edge  32 . A seal can be provided at the intersection of the pipe  14  and the concrete to prevent leakage. 
   Pipe  14  has a smooth inner wall  40  and a corrugated outer wall  42  (i.e. with grooves and ridges, as seen in  FIGS. 1 ,  3  and  5 ). The corrugations serve to strengthen the pipe. Because this cut-off edge can be non-uniform, it is not a suitable surface for sealing. Therefore, for an effective seal to be made between the pipe  14  and the cover  16 , one must be made on the top surface  44  of the top corrugation of the pipe. 
     FIG. 4  shows the cover  16  of the present invention. The cover generally comprises a flat upper disc component  46  and a lower cylinder component  48  protruding downward from the upper disc  46 . The lower cylinder  48  is formed so that it may be inserted snugly within the smooth inner diameter of pipe  14 . The upper disc  46  maintains a diameter slightly larger than the corrugated outer wall of the pipe  42  and is the above ground, exposed portion of the cover system  10 . In the area surrounding the lower cylinder&#39;s protrusion from the upper disc is a slightly raised ring of material  48 . This portion of the upper disc  46  is the contact surface corresponding to the seal on the top corrugation surface  44  of pipe  14 . The mating established between the cover surface  48  and the seal is water tight. Additionally, there is an inclined surface  49  between the flat outer portion of the disc and the raised material  48 . The upper disc  46  of cover  16  contains multiple holes  50  around its periphery which can be used to place a padlock or some other kind of locking mechanism for the prevention of unauthorized access to the septic system. Two cylindrical depressions  52  also exist on the top surface of the cover (see  FIG. 5 ). 
     FIG. 5  shows the cover  16 , pipe  14 , and base  12  of the device as they would be in an assembled device, absent the wrap  17 . Cylindrical depressions  52  are shown as well. Suitable gaskets or other sealing materials are also provided in the seal ares between the pipe  14  and the concrete and between the relatively flat area of the top corrugation of the pipe  14  and the cover. 
     FIG. 6  discloses the final component of the device, wrap  17 , added to the assembly. Wrap  17  is made of high density polyethylene material which surrounds the pipe  14 . Often the corrugations of pipe  14  present a problem when the pipe is buried in the ground, due to frost or other heaving of the surrounding soil. This can cause the pipe to actually be lifted off of the base  12  due to the forces imparted by changing soil conditions. Wrap  17  is intended to prevent this heaving problem. Wrap  17  surrounds the pipe and covers the corrugations so that forces caused by frost or the like are not applied to bottom portions of the corrugations in the pipe. Such forces are what would otherwise cause the pipe to be lifted from the base. The wrap provides a smooth outer wall surface rather than the corrugations in the pipe. 
   Now that the details of the mechanical construction of the septic cover assembly  10  of the present invention have been described, consideration will next be given to its mode of operation. 
   During construction of an underground concrete septic tank, the base member  12  in imbedded into the concrete. The concrete surrounds the outer edge of base member  12  such that concrete, embeds within depressions  26 , completely encapsulates ledge  20 , and extends to the level of rim edge  32  and top of the concrete. A watertight attachment is thus formed between the tank, the base member  12  and the bottom of pipe  14 . Once the concrete hardens, the tank is placed in a hole in the ground. The pipe  14  is cut such that the top of the pipe is approximately even with or slightly above ground level. A seal such as a gasket is positioned so that it surrounds the base member  12 . Corrugated pipe  14  is slid over the exposed riser coupling  24  of the base and up against the channel formed by the rim edge  32 . Next, a seal is placed along the pipe&#39;s top corrugation surface  44  as opposed to the cut edge which tends to be uneven. A cover  16  is then placed within and above pipe  14 , engaging against the seal on the top corrugation surface  44  to form a second watertight connection. The cover  16  is locked with a padlock and opened when access is needed for maintenance or repair of the septic tank. 
   It can be seen, then, that the present invention provides an improved and efficient apparatus for gaining access to a septic tank which functions to effectively seal the tank from water and prevent tank leakage. 
   This invention has been defined herein in considerable detail in order to comply with the Patent Statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment details and operating procedures, can be accomplished without departing from the scope of the invention itself.