Abstract:
A manhole cover frame leveling clip, that attaches by a friction fit to the exterior peripheral flange of a manhole cover frame, and uses an adjustable bolt running through the clip, to manipulate the height and angle of the frame so that the frame is in the same plane or the correct elevation with the finished grade of the roadway surface.

Description:
This application claims benefit under 35 U.S.C. section 119(e) of U.S. provisional patent application 60/119,432, filed Feb. 9, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to manhole/maintenance access hole installation during roadway construction and more particularly to an apparatus that attaches to a manhole cover frame, allowing the manhole cover to be adjusted until it is parallel with and in the same plane with the proposed final or final finished grade of the surfaced roadway. 
     When resurfacing an existing roadway or installing new roads with manholes, it is difficult to position the manhole cover frame accurately so that it is flush with the proposed finished grade of the roadway surface. Manholes are most prevalently made in precast concrete sections and a common configuration consists of a manhole base upon which standard precast manhole sections interlockingly stack. Since the manholes are not necessarily perpendicular to the roadway surfaces, these standard precast manhole sections terminate below grade. Shorter, lighter precast riser rings are interlockingly placed on the top manhole section. Grout or other suitable material is then used between these riser rings and the manhole section to adjust the top end of the riser rings parallel to the proposed grade of the roadway surface. A manhole cover frame, which is typically a large cylindrical cast iron section with internal and external flanges, is placed onto the riser rings. However, since the manhole cover frame weighs hundreds of pounds but must be precisely placed so as to be flush with the finished surface of the roadway and since the riser rings are only roughly positioned with respect to the contour and elevation of the roadway surface, the manhole cover cannot just rest directly upon the precast concrete riser rings, but must be adjusted to precise height and angle relative to the riser rings. Due to the extreme weight of the manhole cover frame, accomplishing precise alignment is difficult. Typically the cover frame is held in proper alignment by the placement of stones or other debris, which may be handy, between the manhole cover frame and the riser rings. 
     Referring to FIG. 1, a cross sectional view of a typical manhole cover frame  10 , the frame includes an outer peripheral flange  12  that is supported directly on the top surface of a riser ring  14 . The riser rings  14  have been adjusted to conform with the roadway grade  18  by the strategic placement of a grout  16  between riser rings  14 . 
     An alternate method of alignment is to suspend the manhole cover frame by wire from dimensional lumber that rests on the finished grade of the roadway. 
     Prior patents for manhole leveling devices also disclose several methods for aligning the manhole frame to the finished roadway surface. U.S. Pat. No. 1,076,386 discloses using leveling screws but requires special fabrication of the cover frame to incorporate brackets to house and support the screws. U.S. Pat. No. 4,075,796 shows a specially fabricated cover frame with an internally threaded body that adjusts for height only. U.S. Pat. No. 3,263,579 also discloses using leveling screws but requires a specially fabricated flange from which the leveling screws operate. U.S. Pat. No. 2,930,295 uses screws to align the manhole cover but requires the fabrication of a two-piece cover frame. 
     SUMMARY OF THE INVENTION 
     The present invention provides a cost effective apparatus and method for precise alignment of a manhole cover frame to a proposed roadway surface that requires no modifications to existing manhole components, nor requires any additional steps in the manufacture of existing manhole components. 
     This invention comprises a clip that fastens to the outer peripheral flange on a manhole cover frame. The clip is threaded to allow a leveling bolt to raise or lower the manhole cover frame with respect to the topmost manhole precast riser ring, allowing for the perfect alignment of the manhole cover frame with the roadway surface. The individual clips may be positioned anywhere along the peripheral flange of the cover frame in accordance with the contour of the roadway surface. 
     Accordingly, it is an object of the present invention to provide an improved low cost manhole cover frame leveling apparatus. 
     It is a further object of the present invention to provide an improved manhole cover frame leveling apparatus that requires no modifications to existing manhole components. 
     It is yet another object of the present invention to provide an improved manhole cover frame leveling apparatus that requires minimal time, effort and equipment to install and to use. 
     It is yet another object of the present invention to provide an improved leveling clip that is suitable for performing a variety of construction leveling tasks with respect to installation of gratings, covers and the like. 
     The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with accompanying drawings wherein like reference characters refer to like elements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a cross sectional view of a typical prior art leveled manhole; 
     FIG. 2 is a perspective view of a manhole frame leveling clip according to the present invention; 
     FIG. 3 is a cross sectional view of the manhole frame leveling clip as installed and properly aligning a manhole cover frame; and 
     FIG. 4 is a cross sectional view of an alternative embodiment manhole frame leveling clip incorporated into a manhole cover frame. 
    
    
     DETAILED DESCRIPTION 
     FIG. 2 is a perspective view of the leveling apparatus according to the preferred embodiment of the present invention. A leveling clip  20  is provided comprising a substantially rectangular body  22  with a “U” shaped channel  24  running parallel to and equidistant between the sides having the largest surface area to form two “legs”  26  and  28 . In the preferred embodiment, one of the legs, leg  26 , is somewhat shorter than leg  28  and both legs have rounded over leading edges  35  for ease of installation, although these are not requirements. The channel  24  extends to a depth exceeding the midpoint of the longitudinal axis of the body  22 . Adjacent the end of the clip which is distal from the opening of the “U” shaped channel  24 , a hole  30  is defined which is threaded in the illustrated embodiment to receive a standard commercial steel bolt  32 . The bolt  32  provides adjustment features as discussed hereinbelow and is suitably sized so as to be able to bear the compressive force load of the manhole cover frame. 
     Referring to FIG. 3, which is a cross sectional view of a manhole with a leveling clip  20  installed, the method of using the invention is as follows. First, after installation of the riser rings  14 , the adjustment bolts  32  are threaded into a number of manhole cover frame leveling clips  20  such that the bolt head  34  is nearest the shorter of the legs  26 . Next, the “U” channel  24  of the manhole cover frame leveling clips  20  are receivably slid onto the outer peripheral flange  12  of the manhole cover frame  10  with the larger of the two legs  28  placed on the bottom surface of the flange so that the end of the adjusting bolt opposite head  34  will rest on the face of riser ring  14  and support the weight of the manhole cover frame  10  when the manhole cover frame  10  is positioned onto the riser ring  14  face. The manhole cover frame is then positioned onto the riser ring and the adjustment bolt  32  is turned to adjust the length of the portion of the bolt that protrudes from the bottom side of the clip until the top of the frame  10  reaches the desired position. Grout or cement is placed around the riser ring and leveling clips  20  to hold the ring in its final position. Protruding portions of the adjustment bolts (if any) are cut below the roadway surface. Finally, roadway material such as asphalt or cement  19  is used to fill in the hole (illustrated by dashed lines) up to the top of the frame. Typically there will be a plurality of clips  20  used in each leveling operation, for example, three or more. However, certain applications may require as few as one clip. In the preferred embodiment, the end of the bolt distal from head  34  contacts the riser ring, but the bolt can be positioned such that head  34  contacts the riser ring, rather than the other end of the bolt. 
     In fabrication of the clip  20 , the tolerance of the width of the “U” channel  24  suitably is chosen to enable a friction fit between the clip  20  and the flange  12  so that installation of the clip onto the flange requires force to be exerted by a striking tool, such as a hammer. 
     In the preferred embodiment, the manhole cover frame leveling clip  20  is fabricated of steel; however, any appropriate material with good load bearing shear strength, such as an aluminum alloy or plastic, may be utilized. 
     In an alternate embodiment, the leveling clip hole is not threaded, but rather is of a smooth bore configuration wherein a leveling rod passes through the hole and bears the weight of the assembly at the underside of the leveling clip, for example, by use of any suitable adjustable stop member to allow height adjustment. A suitable stop comprises a sliding member that can be moved up and down the leveling rod but will maintain position by friction or by cooperative engagement with notches or the like in the rod. 
     In still a further embodiment, as illustrated in FIG. 4, the manhole cover frame  10 ′ has an opening  40  defined in flange  12 ′, the opening being suitably not threaded and of sufficient diameter so that a threaded rod  42  freely passes therethrough. The rod has a nut  44  threaded thereon and the top surface of the nut bears against the bottom surface of the flange  12 ′ so as to support the frame  10 ′. The nut is threaded upwardly or downwardly along the length of the rod  42  to enable adjustment of the frame  10 ′ as desired. Still further, an alternate rod  42 ′ can be unthreaded and an engagement member  44 ′ is substituted for the nut, wherein the engagement member can be secured at any desired location along the length of rod  42 ′. For example, a supporting disk member with a set screw can be provided such that the disk member engages the bottom of the flange  12 ′ while the set screw frictionally secures the position of the disk along the length of the rod  42 ′. Still further, the aperture in the flange  12 ′ can be threaded to receive a threaded rod or bolt therein. 
     Accordingly, plural embodiments are provided, either as pre-manufactured devices combined together with the manhole cover frames or as add-on adjustment members that can be applied in the field, as needed, to standard manhole cover frames. 
     While a plural embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. The appended claims are therefore intended to cover all such changes and modifications as fall within the true spirit and scope of the invention.