Abstract:
The present invention is directed to a clip connector for joining steel ribs together end to end to provide a support for lateral wood or steel beams used to line a tunnel. The clip connector has a generally C shaped cross section with a web section having a width approximately equal to the width of the flange of the steel rib and a length and shape sufficient to overlap the ends of the joined steel ribs. The clip has flanges extending from either side of the web to wrap around the flange of steel ribs and contain the flange of the steel rib.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention utilizes clips to join vertical rolled I-beams (or other structural shapes) used to support lateral wood or steel beams in a “rib and lagging type” tunnel liner and in particular, clips which provide for a maximum, unobstructed tunnel diameter. 
       BACKGROUND OF THE INVENTION 
       [0002]    In a tunneling operations, a machine removes material from the face of the tunnel and moves the removed material rearwardly to be transported to the surface for disposal. As the tunneling machine excavates the tunnel, it is necessary to provide a liner for the tunnel behind the machine. Presently, liners are either wood/steel beams supported by steel ribs, commonly called “rib and lagging”, steel panels or concrete panels. The use of a particular liner system is dependent on ground conditions and cost. 
         [0003]    Wood/steel beams supported by ribs have the advantages of lower cost than either steel or concrete panels as well as being easier and faster to install. Presently, the steel ribs are provided in three or more sections which, when connected together end to end, provide either a complete circle for the desired tunnel diameter or the desired shape for tunnel dimensions. The ribs generally are made by rolling an I-beam structure along one flange to form a curved cross section that supports the ends of the wood/steel beams which are installed between two adjacent ribs. 
         [0004]    Presently the rib ends are generally connected to one another using plates welded onto the ends of the ribs, typically called butt plates. The butt plates are then connected together by bolts. While such an arrangement provides for a secure connection, it does have certain disadvantages. The installation and tightening of the bolts consumes a significant amount of both material expense and time in the operation of installing the tunnel lining. In addition, the butt plates extend into the interior of the tunnel, thus reducing the effective usable diameter of the tunnel. 
         [0005]    There thus remains a need for a less expensive, simpler and quicker way of connecting the steel ribs together. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention is directed to a tunnel liner of a plurality of curved steel rib sections which are joined together end to end to form a ring encircling the tunnel diameter. The rib sections have an I-shaped cross section with opposing flanges joined by a central web. A plurality of the joined rib sections are provided spaced apart along the length of the tunnel. A plurality of wood or steel lateral beams are provided which connect the joined rib sections, the sides of the lateral beams abutting each other and the ends of the lateral beams being contained within the space between the opposing flanges and butting against the central web to form a complete tunnel liner. The improvement comprises a clip connector for joining the curved steel rib sections together end to end to provide the rib encircling the tunnel to support the lateral beams used to line a tunnel. The clip connector has a generally C shaped cross section with a web section having a width approximately equal to the width of the flange of the steel rib and a length sufficient to overlap the ends of the joined steel ribs. The clip has flanges extending from either side of the web with an inwardly extending edge to wrap around the flange of steel ribs and contain the flange of the steel rib in the space between the inwardly extending edge and the web of the connector. 
         [0007]    In an aspect of the invention, there is provided a clip connector for joining steel ribs together end to end to provide a support for lateral wood or steel beams used to line a tunnel. The clip connector has a generally C shaped cross section with a web section having a width approximately equal to the width of the flange of the steel rib and a length sufficient to overlap the ends of the joined steel ribs. The clip has flanges extending from either side of the web with an inwardly extending edge to wrap around the flange of steel ribs and contain the flange of the steel rib. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Preferred embodiments of the present invention are illustrated in the attached drawings, in which: 
           [0009]      FIG. 1  is a perspective view of a wood beam tunnel lining constructed using the steel ribs and clip connector of the present invention; 
           [0010]      FIG. 2  is a perspective view of a preferred embodiment of the clip connector of the present invention; 
           [0011]      FIG. 3  is a perspective view of the clip connector joining adjacent steel ribs; and 
           [0012]      FIG. 4  is a cross section view of the clip connector joining the adjacent steel ribs. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0013]    A typical steel rib and lateral beam tunnel lining using the clip of the present invention is illustrated in  FIG. 1  generally indicated by the numeral  10 . The steel rib and wood beam tunnel lining  10  is comprised of steel ribs  12  which are generally an H or I beam with interior flanges  14  and exterior flanges  16  joined together by a central web  18 . The interior flanges  14  will be to the inside of the tunnel lining  10  and the exterior flanges  16  will be adjacent the wall of the tunnel. The spacing between the flanges  14  and  16  of the steel rib  12  is dimensioned to accept the ends of the wood or steel beams  20  as will be described below. 
         [0014]    A plurality of steel rib sections  12  are joined together end to end to form a complete circle encircling the interior of the tunnel. Generally, the number of curved rib sections  12  utilized to complete the circle will be selected based upon the tunnel diameter. Most commonly 3 or 4 such curved steel rib sections  12  are utilized for most tunnel diameters, however, those of skill in the art will be able to readily determine the number. 
         [0015]    The complete circles of the steel rib sections  12  are spaced apart along the length of the tunnel at a distance approximately equal to the length of the wood or steel lateral beams  20  used in the tunnel lining  10 . The lateral beams  20  are installed between the complete circles of the steel rib sections  12  with the sides  22  of the lateral beams  20  abutting each other and the ends  24  of the lateral beams  20  being contained within the space between the opposing interior flanges  14  and exterior flanges  16  and butting against the central web  18  to form the tunnel liner. The process used to install the liner will be described further below. 
         [0016]    The ends of the steel rib sections  12  are connected together utilizing a clip connector  30  in accordance with the present invention. A first preferred embodiment of a clip connector  30  in accordance with the present invention is illustrated in the figures. Clip connector  30  is generally C shaped, having a web  32  and flanges  34  extending from either side of the web  32 . Flanges  34  have an inwardly extending edge  36 , the space between the web  32  and the inwardly extending edge  36  being of a dimension and shape to accept a flange  14  or  16  of the steel rib section  12  as will be described. 
         [0017]    A tunnel wall is constructed using the steel ribs  12  and lateral beams  20  as follows. The clip connector  30  is preferably installed on one of the ends of the steel ribs  12 . The steel rib sections  12  are then placed against the wall of the tunnel and spaced apart to lie against the tunnel wall. The clip connectors  30  are then slid along the flange  14  or  16  of the steel rib section  12  until they engage the flange  14  or  16  of the adjacent steel rib section  12  and bridge the gap between the steel rib sections  12 . 
         [0018]    Typically, the steel rib sections  12  will be of a length slightly less than the complete diameter of the final tunnel lining  10 . This provides a slight gap between the ends of the installed steel rib sections  12 . This gap allows for easier installation of the steel rib sections  12  and it provides a space between the ends of the steel rib sections  12  to allow them to pass one another when being placed against the tunnel wall. The gap between the flanges  14  or  16  of the adjacent steel rib sections  12  is bridged by the length of the clip connector  30  of the present invention. In order to help in maintaining the spacing of the steel rib sections  12 , the space between the ends of the webs  18  of the adjacent steel rib sections  12  is filled by a wedge (steel or other material)  40  to hold the steel rib sections  12  in the proper spaced apart relationship. 
         [0019]    The lateral beams  20  are then placed in the steel ribs  12  and the next row of steel ribs  12  is installed on the opposite end  24  of the wood beams  20 . These steel ribs  12  are installed by placing them over the ends  24  of the wood beams  20  and sliding the clip connectors  30  to engage the adjacent steel rib  12  and lock the steel ribs  12  together. 
         [0020]    The clip connector of the present invention provides for an easier and faster way of installing tunnel linings of steel ribs and wood/steel beams. To tie the ends of the steel ribs together requires sliding the clip connector until the adjacent rib is engaged. This is much simpler and faster than having to insert bolts and tighten them down. The clip connectors of the present invention also do not require the attachment of the additional butt plates for the bolts thus also reducing the cost of the steel ribs. 
         [0021]    The clip connector of the present invention also allows for tunnels to be constructed with a larger usable diameter than the prior art systems. The clip connector of the present invention lies generally flush against the steel rib of the tunnel lining and does not project into the tunnel as the butt plates of the prior art attachments do. 
         [0022]    While the clip connector illustrated in the drawings has a generally C shaped cross section, it will be readily apparent to those of skill in the art that other arrangements for the clip connector may be provided. For example the clip connector could have a generally perpendicular side flange connected to the web at one edge and extending downwardly from the edge of the web and an extension extending inwardly and upwardly from the opposite edge of the flange. In this way, the clip connector could adapt to variations in the thickness of the flange of the rib section or variations in the curvature of the rib section for various tunnel diameters. 
         [0023]    The clip connector of the present invention may be used in many types of tunneling operations including utility tunnels, mining operations, etc. The clip connector may also be used in generally vertical as well as generally horizontal shafts. While the clip connector has been described for use in tunneling applications, it will be apparent to those of skill in the art that the clip connector may also have use in other applications where ends of beams are to be connected. 
         [0024]    Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those of skill in the art that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.