Abstract:
A machine and method for providing a folded liner for insertion into a pipe, comprises an upper section and a lower section. A flattened heated thermoplastic liner is fed downwardly through the upper section to the lower section, where it is redirected and fed substantially horizontally from the lower section. The flattened liner introduced to the upper section is broadly indented at one side of the liner and is then more acutely indented to provide loops disposed side-by-side in a substantially horizontal direction. The lower section reorients the loops so that they are stacked side-by-side in a substantially vertical direction. The liner is cooled as its leaves the lower section to maintain its cross-sectional configuration. The upper section is separable from the lower section, and portions of the upper and lower sections are displaceable and removable to facilitate insertion of the liner into the machine and removal of the machine from the liner.

Description:
BACKGROUND OF THE INVENTION 
     This invention is concerned with lining of sewer pipes and the like and is more particularly concerned with providing a folded liner that can be pulled through a pipe for later expansion by conventional techniques. 
     Because of the expense of repairing and/or replacing defective sewer pipes and the like, an industry practice has developed in which the pipes are lined with a plastic liner, thereby to provide a new flow path within the defective pipe. In order to facilitate the pulling of the liner through the pipe, techniques have been developed for folding a flattened thermoplastic liner before it is introduced to the pipe so that the cross-dimensions of the liner, when folded, are substantially less than the cross-dimensions of the pipe. However, providing a folded liner efficiently, reliably, and economically has been a problem. The present invention is a solution to that problem. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In a broad sense, the invention concerns a machine and method of providing tubing that is folded about a longitudinal axis whereby the cross-section of the tubing assumes a configuration comprising overlapping loops. More particularly, the loops are formed as the tubing is fed in a first direction, and then the tubing is redirected and the orientation of the loops is changed. 
     In a preferred embodiment, a machine of the invention comprises an upper section and a lower section, which are preferably separable. As a heated flexible liner of flattened cross-section is fed into and through the upper section to the lower section, it is broadly indented at one side thereof and is then more acutely indented to fold the liner so that the cross-section assumes a configuration in which a pair of outer loops are disposed at opposite sides of a central loop along a substantially horizontal direction. 
     As the folded liner is fed through the lower section, it is redirected so that it is fed substantially horizontally, with the cross-sectional loops stacked substantially vertically. The liner fed from the lower section is cooled to reduce its flexibility, so that the cross-sectional configuration is maintained as the liner is drawn into and through a pipe, in a conventional manner. 
     In a preferred embodiment of the invention, portions of the upper and lower sections can be displaced, and can also be removed, to facilitate initial entry of the liner into the upper section, and also to facilitate withdrawal of the machine from the liner after the liner has been drawn to a desired position in the pipe. After the liner has been installed in the pipe, and the machine withdrawn, a trailing portion of the liner can be cut and the liner can be heated and expanded by conventional techniques, thereby unfolding the liner and providing a round cross-section. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be further described in conjunction with the accompanying drawings, which illustrate a preferred and exemplary (best mode) embodiment of the invention and wherein: 
     FIG. 1 is a perspective view of the upper section; 
     FIG. 2 is a perspective view of a removable portion of the upper section; 
     FIG. 3 is a further perspective view of the upper section showing components that are not visible in FIG.  1  and showing the cross-sectional configuration of the liner after folding; 
     FIG. 4 is a top plan view of the upper section showing the cross-sectional configuration of the liner as it is broadly indented; 
     FIG. 5 is a perspective view of the lower section; 
     FIG. 6 is a fragmentary perspective view showing displacement of a removable portion of the lower section; 
     FIG. 7 is a perspective view showing the lower section with the removable portion of FIG. 6 removed; 
     FIG. 8 is a side elevation view showing the upper section assembled on the lower section; 
     FIG. 9 is an end view of the machine shown in FIG. 8, illustrating the cross-sectional configuration of the folded liner as it leaves the lower section; and 
     FIG. 10 is an inverted perspective view of a cooling manifold that can be used in the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIGS. 8 and 9, a machine in accordance with the invention comprises an upper section  10  mounted on a lower section  12 . The upper section, shown more particularly, in FIGS. 1-4, comprises a casing  14  that is open at the top and at one side thereof. A portion  16  of the upper section, shown in FIG. 2, is displaceable and can be removed from the remainder of the upper section. Removable portion  16  comprises a pair of side plates  18 ,  20  supporting a convex, bulbous forming roller  22  that is mounted rotatably on the side plates. 
     An end plate  24  connects the side plates and supports a rod  26  with ends  28 ,  30  that project from a pair of mounting brackets  32 ,  34  attached to the end plate. The projecting ends of the rod are received within L-shaped slots  36  in sidewalls  38 ,  40  of the upper section, the sidewalls being notched to receive the side plates of the removable portion  16 . Washers  42  (FIGS. 1 and 9) may be attached to the projecting ends of the rod  26 . 
     Handles  44  are mounted on the side plates of the removable portion so that the removable portion can be easily turned and lifted from the position shown in FIG.  1 . The ends  46  of the side plates, opposite to the projecting ends of the rod  26 , are curved, and the juxtaposed surfaces of the sidewalls  38  and  40  have a complementary curvature, so that the removable portion can be turned about the axis of the rod and then shifted along slots  36  and lifted out of the slots. As shown in FIGS. 1 and 4, a cylindrical backup roller  48  is rotatably supported on the sidewalls of the upper section in close proximity with the forming roller  22 . 
     Four rectangular plates  50  are attached to and extend downwardly from a bottom portion of the upper section to embrace a top portion of the lower section  12  as shown in FIGS. 8 and 9. Removable pins  52  are inserted into aligned bores in the plates and the juxtaposed walls of the lower section. 
     As shown in FIGS. 3 and 8, the upper section includes an indenting assembly, which, in the preferred form comprises a rotatable disk  54  and a cylindrical finger  56  that projects substantially horizontally into the interior of the upper section below the disk. The disk is supported on a shaft  57  extending between sidewalls of the upper section and removable therefrom. The finger is supported on a pair of brackets  58  attached to a plate  60  having channel pieces  62  that slide along converging edges  65  of an opening at one side of the upper section. When installed in the upper section, the plate  60  rests atop two mounting plates  50  as shown in FIG.  3 . The cylindrical finger  56  is supported on the brackets  58  by a pin  64  that extends through aligned bores in the brackets and an end portion of the finger, and the mounting of the finger is such that, when sufficient manual force is exerted, the finger can be turned downwardly from the position shown in FIG.  3 . 
     The forming roller  22  and the backup roller  48  rotate about substantially horizontal axes. Preferably, there are two additional rollers,  66 ,  68  (see FIG.  3 ), below and at opposite sides of the indenting assembly, that rotate about substantially horizontal axes transverse to the rotational axes of the forming roller and the backup roller. 
     As shown in FIG. 5, the lower section  12  comprises a casing  70  with a rectangular inlet  72  at the top and a rectangular outlet  74  at one end. The inlet is defined by four rollers  76 ,  78 ,  80 , and  82  that rotate on corner blocks  84  about substantially horizontal axes. The outlet  74  is defined by four rollers  86 ,  88 ,  90 , and  92  that rotate on corner blocks  94 . One pair of opposed rollers,  86 ,  90 , rotates about substantially horizontal axes and the other pair of opposed rollers,  88 ,  92 , rotates about substantially vertical axes. The corner blocks  94  shown at the top of rollers  88  and  92  in FIG. 5 are actually formed in two parts. Portions  95  of these corner blocks are shown in FIG. 7, and mating portions  97  are shown in FIG.  6 . 
     As shown in FIG. 6, the lower section  12  has a displaceable and removable portion  96  that supports one of the rollers,  80 , of the inlet  72  and one of the rollers,  86 , of the outlet  74 , as well as two additional rollers  98 ,  100  that are rotatable about substantially horizontal axes. Short rods  102 , one of which is shown in FIG. 6, project from side plates  104  and  106  of the removable portion  96  and are received in slots  107  (FIG. 7) in sidewall portions  108  and  110  of the lower section. The ends of the projecting rods may have washers  112  fixed thereto. 
     Openings  114  in the side plates of the removable portion provide hand grips to permit the removable portion to be turned from the position shown in FIG. 5 to the position shown in FIG. 6, whereupon the projecting rods  102  can be displaced from their slots  107  so that the removable portion can be removed from the lower section. The lower section will then appear as shown in FIG.  7 . The removable portion  96  has a cover plate  116  that closes off the lower section above the outlet  74  when the removable portion is in the position shown in FIG.  5 . In this position angle pieces  118  shown in FIG. 6 mate with plates  119  to form the corner blocks  84  adjacent to the plate  116 . 
     As shown in FIGS. 5,  7 , and  8 , the lower section  12  has an inclined plane defined by a sloping wall  118  (or, alternatively, by a series of rollers), angulated at approximately 45° with respect to horizontal. The rollers  98  and  100  of the removable portion are opposed to the sloping wall  118  and define a tangent plane that is substantially parallel to the sloping wall. 
     As shown in FIGS. 5-9, a pair of rectangular cross section tubes  120  are attached to opposite sides of the lower section. Rectangular cross-section rods  122 , one of which is shown in FIG. 8, can be inserted through the tubes so as to project from opposite ends thereof and can be fixed in position in the tubes by inserting pins (not shown) through aligned bores in juxtaposed walls of the rods and the tubes. The projecting ends can serve as handles for lifting and lowering the lower section. 
     Projecting ends of the rods  122  also serve to support a cooling manifold  124 , the base of which has rectangular cross-section tubes  126  that receive respective rod ends and that are pinned in position. A threaded fitting  128  at the top of the manifold is provided so that a hose can be attached to the manifold to supply cooling water. A similar fitting  130  provided on the cover plate  116  of the removable portion as shown in FIGS. 5,  8  and  9 , can be connected to a hose for additional cooling if desired. FIG. 10 is an inverted view of the manifold showing a plurality of holes  131  through which water is ejected. A baffle or baffles (not shown) can be provided in the manifold to distribute the supply of water evenly to all of the holes. 
     To assemble the upper section  10  with the lower section  12  as shown in FIGS. 8 and 9, the upper section is lowered onto the top of the lower section until bars  132 , one of which is shown in FIG. 1, that extend between pairs of plates  50  rest on corner blocks  84  at the top of the lower section. The pins  52  (FIG. 8) are then inserted, as described earlier, to lock the upper section to the lower section. The lower section has projecting tubulations  134  for receiving jack screws  136 , the purpose of which will be apparent in the following description. 
     A typical application of the invention to provide a folded plastic liner in a sewer pipe will now be described. 
     It is well known in the art to pull a folded thermoplastic liner through a sewer pipe or the like by a pulling cable that is attached to a leading end of the liner. The coupling between the cable and the liner may include a ball and a swivel. The flattened liner may be supplied from a reel on which the liner is wound, the reel being placed in a steam cabinet to soften the thermoplastic liner material prior to its being fed into the machine of the invention. The machine of the invention can be installed below ground in a manhole, supported on a ledge directly or with intermediate support members and can be braced in position by means of the jack screws  136 . The top of the upper section  10  is positioned below the ground level opening to the manhole, and the outlet  74  of the lower section  12  is aligned with an entry opening of the sewer pipe. 
     To facilitate insertion of the cable pulling assembly and the leading end of the liner into the upper section, the removable portion  16  of the upper section can be removed, or simply turned out of the way. After the pulling assembly and the leading end of the liner have been drawn through the machine of the invention, the removable portion of the upper section is returned to its home position shown in FIG.  1 . Installation of the machine of the invention in the manhole is simplified by the separability of the upper and lower sections, so that the lower section can be installed in the manhole first and then the upper section installed atop the lower section. 
     The liner fed downwardly into the upper section has a flattened elongated cross-section L that passes between the bulbous forming roller  22  and the backup roller  48  as shown in FIG.  4 . The forming roller forms a broad indentation in one side of the liner cross-section. This indentation becomes much more acute as it passes the indenting assembly comprising the rotating disk  54  and the finger  56 , as shown in FIG. 3, so that the liner is folded about a longitudinal axis at a central region and defines a pair of outer loops L 1  and L 2  disposed at opposite sides of a central loop L 3 , with loop cross-sections arranged side-by-side in a substantially horizontal direction. As shown, the central loop L 3  is open at one side of the liner and provides a longitudinal groove facing one side of the machine, into which the disk  54  and the finger  56  are inserted. The indenting assembly may, in certain applications, have a different construction from the rotating disk  54  and the finger  56 , comprising only the disk or the finger, for example. The forming roller  22  has been found to be particularly effective in initiating the folding of the liner and in smoothing out dimples or other imperfections in the heated liner. 
     The folded liner fed downwardly from the upper section  10  into the lower section  12  impinges on the sloping wall  118  of the lower section, which redirects the liner so that it is fed substantially horizontally from the outlet  74  of the lower section, with the outer loops L 1  and L 2  disposed above and below the central loop L 3 , with the loop cross-sections arranged side-by-side in a substantially vertical direction and with the longitudinal groove provided by the open loop L 3  facing the same side of the machine as in the upper section, as shown in FIG.  9 . As the folded liner leaves the lower section it is cooled by cooling water supplied to the cooling manifold  124  to reduce the flexibility of the liner in order that its folded configuration can be maintained as the liner is pulled through the sewer pipe to the desired extent. 
     When a liner is pulled, it may tend to shift or twist undesirably. The combination of the forming roller  22  and the backup roller  48  are effective to establish the desired initial orientation of the liner, and the various rollers employed in the lower section are effective in guiding the liner and preventing undesired shifting and twisting. 
     When the liner pulling is complete, it is necessary to remove the machine from the liner. The construction of the machine of the invention greatly facilitates such removal. The removable portion  16  of the upper section can be removed, and the indenting assembly removed, so that the upper section can then be lifted and shifted laterally of the liner to pass the liner between the edges  65  in FIG. 3, thereby to separate the upper section from the liner and permit the upper section to be extracted from the manhole. Then the removable portion  96  of the lower section can be removed, so that the top and one side of the lower section are open as shown in FIG.  7 . The lower section can then be shifted and lifted to separate it from the liner and to extract it from the manhole. 
     A trailing portion of the liner above ground can then be cut so that the installation of the liner can be completed using conventional techniques to soften and expand the liner to the desired round cross-section. 
     While a preferred embodiment of the invention has been shown and described, it will be apparent to those skilled in the art that modifications can be made without departing from the principles and spirit of the invention as defined in the appended claims. For example, the machine of the invention can be used above ground, rather than in a manhole, and can be used to provide folded tubing in applications other than sewer pipe lining. Furthermore, terms such as “substantially vertical” and “substantially horizontal” are relative terms used herein in describing preferred orientation of axes, for example, and the redirection of the liner from the upper section through the lower section, but it is to be understood that the liner feed need not be along strictly vertical or horizontal directions. For example, the liner fed from the lower section can be provided to a sloping pipe, which, within the context of the invention, is to be considered as “substantially horizontal”.