Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims priority to U.S. Provisional patent application Ser. No. 60/825,648, filed Sep. 14, 2006. 

   FIELD OF THE INVENTION 
   The present invention is directed to a grate assembly for enclosing a drainage trench, and more specifically, to a frame for retaining a grate structure over a drainage trench. 
   BACKGROUND OF THE INVENTION 
   Trenches for directing storm water to subterranean basins are commonly found in paved surfaces such as driveways and parking lots, and are typically found across vehicular entrances and interior surfaces of the pavement. To allow for vehicular travel over the trench, these trenches are typically covered by substantial grates or grating systems and assemblies, portions of which are embedded into the surrounding pavement. 
   Typical trench grate assemblies include two parts: a frame section and a grate section. The frame section comprises a metal component that is positioned over a ledge formed in the pavement along the sides of the trench and is sized and dimensioned to receive the grate. A portion of the frame is typically formed to be received in the pavement surrounding the trench, to anchor the frame in position. The grate provides a surface that can support a vehicle traversing the trench, but includes apertures that allow water and other fluids to flow into the underlying trench. The grate is typically constructed of individual pieces that are laid end to end along the trench to provide an overall grating system of a selected length. Each frame piece typically includes apertures sized and dimensioned to receive threaded fasteners, and the frame pieces are coupled to the frame using a fastener such as a threaded coupling device that extend through the apertures formed in the frame, and into the concrete ledge. 
   Although these prior art devices provide suitable drainage trench structures, the need for a ledge for mounting the frame limits the size, and particularly the width, of the drainage system that is provided by the frame construction. Additionally, because a corresponding ledge is required in the grate, a significant amount of material is devoted to mounting the drainage system, rather than to providing a useable drainage structure, thereby increasing the cost of the overall trench system. Furthermore, because the frame rests on a concrete ledge, the apertures for receiving fasteners to join the frame and grate members together necessarily rest on the ledge and can become filled with dirt or debris, making it difficult or impossible to properly tighten the fasteners. In addition, prior art trench frames have relatively limited framing for retaining the frame in the concrete, and therefore can be subject to damage when used heavily or subjected to substantial weights. The present invention addresses these problems. 
   SUMMARY OF THE INVENTION 
   In one aspect of the invention, a frame for retaining a trench grate over a drainage trench is provided. The frame comprises a support member having a sidewall for alignment along a wall of the drainage trench and an upper and a lower surface, and a substantially horizontal flange extending substantially perpendicular to the sidewall from a point between the upper and lower surfaces for supporting a grate over the drainage trench at a position above a surface of the drainage trench. 
   In another aspect of the invention, the frame further comprises a reinforcement member offset a distance from a side of the support member opposite the substantially horizontal flange and at least one rib member coupling the support member to the reinforcement member. 
   In yet another aspect of the invention, a top surface of the rib member is angled downward from a back sidewall of the support member to the top surface of the reinforcement member. 
   In still another aspect of the invention, the horizontal flange includes an aperture for receiving a threaded fastener for coupling a trench grate to the frame. 
   In another aspect of the invention, a frame for retaining a trench grate over a drainage trench is provided. The frame comprises a support member, having a length dimension extending along a wall of the drainage trench, and a substantially vertical sidewall for alignment along a substantially vertical wall of the drainage trench. A substantially horizontal flange extends from the sidewall of the support member for supporting a grate in the drainage trench. A reinforcement member, substantially parallel to the length dimension of the support member, is offset a distance from a side of the support member opposite the substantially horizontal flange, and a plurality of rib members spaced along the length of the support member and coupling the support member to the reinforcement member. 
   In still another aspect of the invention, a drainage trench is provided comprising a trench formed in a concrete pavement structure, the trench having first and second parallel sidewalls, and a bottom surface. A frame is embedded in the concrete pavement structure, and includes a vertical support aligned along a side of each of the first and second parallel sidewalls of the trench, and a substantially horizontal flange extends from each of the vertical supports toward a center of the concrete trench over the bottom surface of the trench. A reinforcement member is embedded in the concrete trench parallel to and offset a distance from the vertical support and embedded in the concrete trench. A plurality of rib members extending between the frame and the reinforcement member are embedded in the concrete surrounding the trench. A grate is received in the frame to cover the trench. 
   These and other features and characteristics of the present invention will be apparent from the description which follows. In the detailed description below, preferred embodiments of the invention will be described with reference to the accompanying drawings. These embodiments do not represent the full scope of the invention. Rather the invention may be employed in other embodiments, and reference should therefore be made to the claims herein for interpreting the breadth of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a top view of a trench assembly including a frame constructed in accordance with the present invention assembled as part of a drainage trench. 
       FIG. 2  is a top view of the trench assembly of  FIG. 1 , illustrating the assembly before paving materials are added to form a drainage trench. 
       FIG. 3  is a top view of a single frame section, including a portion that is embedded in concrete. 
       FIG. 4 , a cutaway side view of the trench assembly taken along the line  4 - 4  of  FIG. 3 . 
       FIG. 5 , a cutaway view of the trench taken along line  5 - 5  of  FIG. 3 . 
       FIG. 6  is a cutaway view of the trench taken along line  6 - 6  of  FIG. 3 . 
       FIG. 7  is a cutaway view of the trench taken along line  7 - 7  of  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the Figures and more particularly to  FIG. 1 , a top view of a trench grate assembly  10  as assembled over a drainage trench  12  is shown. The trench grate assembly  10  generally comprises a frame  14  and a plurality of grate sections  16 . The frame  14  extends along and adjacent the sides of the drainage trench  12 , and is embedded in the pavement  21  surrounding the trench  12 . The grate sections  16  are aligned end to end over the drainage trench  12  in the frame  14 , and each include a plurality of apertures  20 , which receive fasteners  18  for retaining the grate sections  16  on the frame  14 , as described more fully below. Preferably, as shown here, an aperture  20  is provided adjacent each corner of the grate section  16 . Various other methods of securing the grate sections to the frame, including coupling and locking devices, fasteners, and other devices could also be used. The pavement  21  is typically concrete, although various other types of paving materials can also be used, as will be apparent to those of skill in the art. 
   Referring now to  FIG. 2 , a top view of the trench grate assembly  10  is shown before it is embedded in the pavement  21 . The frame  14  comprises a plurality of frame sections  15  that are sized and dimensioned to be aligned along the sides of the drainage trench  12 , end to end. Each frame section  15  includes a grate support member  22 , a reinforcement member  24  that is parallel to a length of the grate support member  22 , and a plurality of spaced rib members  26 . The rib members  26  are substantially perpendicular to the length of each of the grate support member  22  and the reinforcement member  24 , and connect the grate support member  22  and the reinforcement member  24  together. Referring now also to  FIG. 3 , from a top view, it can be seen that a space  17  is formed between the support member  22 , reinforcement member  24 , and adjacent rib member  26 . Referring now also to  FIG. 6 , the rib members  26  provided at opposing ends of the grate support member  22  can include one or more aperture  30  for receiving fasteners  32  for coupling adjacent frame sections  15  together. Although apertures and threaded fasteners are shown here, it will be apparent that various other coupling or locking devices could also be used to join the adjacent frame sections  15 . 
   Referring now also to  FIGS. 3-6 , a top view of a frame section  15  and cutaway side views taken through the frame section  15  are shown, illustrating the cross sectional construction of the frame section  15  when embedded in pavement  21  surrounding a trench  12 . Referring first specifically to  FIG. 4 , a cutaway view taken along the line  4 - 4  in  FIG. 3  is shown, illustrating a cross section of both the grate support member  22  and the reinforcement member  24 . In cross section, the grate support member  22  includes a substantially vertical member  25 , including an inner sidewall  23  and an outer sidewall  27  that extend from a top surface  38  that is substantially aligned with the surface of the pavement  21 , to a lower surface  40  embedded in pavement  21  in a position adjacent the trench  12 . The width of the vertical member  25  between the inner and outer sidewalls  23  and  27  is relatively narrow at the upper surface  38 , widens through a center portion of the member  25  and then tapers inward toward the lower surface  40 . 
   Referring still to  FIG. 4 , a substantially horizontally-extending flange  28  extends from the vertical member  25 , in a direction substantially perpendicular to the vertical member  25 , into the interior of the trench  12 , and inwardly beyond the trench sidewall to that the space below flange  28  is open. The flange  28  is positioned a distance below the upper surface  38  of the support member  25  selected to be substantially equivalent to the height of a grate section  16  to be received in the frame  14 , such that the grate section  16  is aligned with the upper surface  38  of the frame  14  and the surface of the pavement  21  when positioned on the flange  28 . The horizontal flange  28  can be, as shown here, substantially centered between the upper surface  38  and lower surface  40  of the vertical member  25 . The upper surface  46  of the flange  28  is preferably flat, and generally perpendicular to the sidewall  23  of the vertical member  25 , although, as shown here, the sidewall  23  may be angled slightly inward as it approaches the upper surface of the trench  12  to provide a widened opening for receipt of a grate section  16  on the flange  28 . The lower surface  48  of the flange  28  includes a substantially horizontal portion and a rounded corner  49  where the flange  28  connects to the vertical support  25 , to reinforce the connection between the vertical support  25  and the horizontal flange  28 . Referring now also to  FIG. 7 , the flange  28  provides a cantilevered seat for a corresponding grate section  16 . Apertures  19  can be provided in the flange  28  to mate with apertures  20  provided in the grate sections  16 , and to receive threaded fasteners  18  or other coupling devices for retaining the grate sections  16  in the frame  14 . 
   Referring still to  FIG. 4 , in cross-section, the reinforcement member  24  is also vertically oriented, but is substantially lower in height than the support member  22 , and is entirely embedded in the pavement  21 . As shown here, the reinforcement member  24  is about one third as tall as the support member  22 . The lower surface  34  of the reinforcement member  24  is aligned with the and substantially parallel to the lower surface  40  of the support member  22 . 
   Referring again to  FIG. 3  and also to  FIG. 5 , a cross sectional view taken through a rib member  26  is shown. As described above, rib members  26  are spaced along the frame section  15 , and extend between the reinforcement member  24  and grate support member  22 , joining the reinforcement member  24  to the grate support member  22 . The rib members  26  include an angled upper surface  42  that extends between the upper surface  32  of the reinforcement member  24 , and the outer sidewall  27  of the vertical support  25  of the grate support member  22 , where the rib member  26  is coupled to the grate support member  22  at a position near the upper surface  38 . The lower surface  44  of the rib member  26  extends continuously between the lower surface  40  of the grate support member  22  and the lower surface  34  of the reinforcement member  24 , such that the rib member  26  substantially encloses the space between the reinforcement member  24  and grate support member  22 , providing a solid reinforcement and back structure for reinforcing the frame  14  and supporting the grate sections  16  in the frame  14 . In one embodiment of the invention, the upper surface  42  of the rib member  26  is angled at an angle of substantially one hundred and thirty five degrees with respect to the upper surface  32  of the reinforcement member  24 . This angle, however, is not critical to the invention and various other angles could also be used. As described above, the support member  22 , the reinforcement member  24 , and the rib members  26  define generally rectangular spaces between them. Concrete or other pavement materials  21  can flow into these spaces and set, thereby securely anchoring the frame  14  in the pavement. 
   Referring again to  FIG. 2 , to construct a drainage trench  12  including a frame  14  and trench grate assembly  10  as described above, a wood frame for forming trench  12  in the pavement  21  is typically provided (not shown). The frame  14  is then assembled along the edge of the wood framing by aligning a plurality of frame sections  15  end to end along a side of the trench  12 . The frame sections  15  can then be coupled together by inserting threaded fasteners  32  through apertures  30  in adjacent frame sections  15 . Rebar or other reinforcement devices can be threaded through the space between the support member  22  and the reinforcement member  24  and coupled to framing or other elements for constructing the trench  12 . For example, U-shaped rebar components can be provided over the sections of the reinforcement member  24  between adjacent rib members  26 . After the frame  14  is assembled, pavement  21  such as concrete or other suitable material is poured around the frame  14  and associated framing members, providing a trench  12  with the frame  14  embedded as shown in  FIGS. 4 and 5 . As described above, the pavement  21  can flow through the space between the support member  22  and reinforcement member  24  between rib members  26  to encase the frame  14  within the pavement, providing a frame with substantial structural integrity. 
   After the trench  21  and frame  14  are constructed, grate members  16  are inserted into the frame  14 . The apertures  20  in the grate members  16  are aligned with mating apertures in the horizontal flange  28 , and threaded fasteners  18  or other coupling devices are inserted through the aligned apertures to couple the grate members  16  to the frame  14 . The reinforcement member  24  and rib members  26  provide a back structure for supporting the weight of the grate  16  in the frame without the need for a concrete ledge as required in prior art devices. Because the flange  28  is cantilevered over the trench, the area immediately below the flange  28  is open, rather than enclosed with concrete. Therefore, the trench has a larger surface area than prior art trenches. Furthermore, because the area immediately below the flange  28  is open, dirt and debris falls through the apertures  19  in the frame  14 , rather than collecting in the apertures, as in the prior art. Because the apertures remain open, the insertion of fasteners into the apertures is easier than in prior art devices, and is not impeded by dirt and debris collected in the frame. Additionally, because the frame structure is substantially embedded in concrete, and easily anchored with rebar components, a frame of substantially greater structural integrity can be achieved. This structure integrity is further increased through the use of fastening elements, such as the threaded fasteners  32  which connect adjacent frame sections. 
   Although a preferred embodiment of the invention has been described in considerable detail above, many modifications and variations to the preferred embodiment described, however, will be apparent to a person of ordinary skill in the art. In order to apprise the public of the various embodiments that may fall within the scope of the invention, the following claims are made.

Technology Category: e