Abstract:
A frame assembly includes a shoe frame and a roller frame. The shoe frame includes an inflatable bladder thereon and the roller frame includes at least one roller that is rotatably mounted thereto. The method of the present invention comprises placing the shoe within a pipe and inflating the bladder so as to secure the shoe frame within the pipe. A flexible cable is then trained around the roller and into the flexible pipe.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a method and apparatus for feeding cable into a pipe. 
   It is often desirable to feed elongated flexible cables into sewer pipes. These cables may be video cables, hoses used for equipment repairing the pipeline, electric cables for powering repair devices within the pipeline, or other flexible cables. 
   These cables are usually fed downwardly into a manhole and then horizontally into a sewer pipe which communicates with the bottom of the manhole. Often the ends of the sewer pipe have sharp edges, and many of these cables can be damaged by scraping against the sharp edges of the end of the sewer pipe. 
   Accordingly rollers have been made available for guiding the cables away from the ends of the sewer pipe when the cables are being fed into the sewer pipe. These devices usually include a shoe which fits within the sewer pipe, and a plurality of rollers that are outside the sewer pipe. The cable is trained around the rollers and then into the sewer pipe. 
   Existing shoes are typically made of steel or aluminum. The front toe of the shoe is inserted into the sewer pipe. Poles are attached to the top of the shoe and the opposite ends of the poles are hung onto the top of the manhole or the adjacent pavement. The cable is guided around the rollers from a horizontal position within the pipe to a vertical position extending upwardly out of the manhole. Usually several rollers are utilized to maintain a gradual radius during the bend. Furthermore the shoe is designed to protect the cable or hose from contacting the edge of the pipe so as to avoid the sharp edges of the pipe. 
   During pipeline maintenance or rehabilitation of the pipelines cables and/or hoses are strung through the pipe for many reasons, including cleaning, video inspection, robot tools and insertion of pipelining materials. During these maintenance procedures the cables and hoses are winched with a high tension and it is crucial that the bottom roller shoe does not kick out of the pipe or become dislodged in any way. If the shoe moves sideways or is kicked completely out of the pipe the cables and hoses will be damaged, costing typically thousands of dollars for replacement. 
   As used herein the term cable includes any type of hose, cable, electric cord, or other elongated flexible member which is fed into a pipe. 
   Therefore a primary object to the present invention is the provision of an improved method and apparatus for feeding cable into a pipe. 
   A further object of the present invention is the provision of apparatus which can be affixed tightly within the sewer pipe during use so that it will not become dislodged. 
   A further object of the present invention is the provision is an approved apparatus for feeding cable into a pipe which has a bladder which can be inflated to tightly secure the apparatus within the end of the sewer pipe. 
   A further object of the present invention is the provision of a method and apparatus for feeding cable into a pipe which includes a detachable member that can be replaced with other detachable members sized to fit within sewer pipes of different dimensions. 
   A further object of the present invention is the provision of an improved apparatus for feeding cable into a pipe which permits the cable to be tensioned, but which maintains the cable free from contact with the sharp ends of the sewer pipe. 
   A further object of the present invention is the provision of an improved apparatus for feeding cable into a pipe which includes a plurality of rollers that maintain a gradual radius during the bend of the cable from a horizontal position within the pipe to a vertical direction. 
   A further object of the present invention is the provision of an apparatus that can be inserted into the sewer pipe and attached to the sewer pipe without the need of a person descending into a manhole. 
   A further object of the present invention is the provision of an improved method and apparatus for feeding cable into a pipe which is economical to manufacture, durable in use, and efficient in operation. 
   BRIEF SUMMARY OF THE INVENTION 
   The foregoing objects may be achieved by an apparatus for feeding an elongated flexible cable into a pipe. The apparatus includes a shoe frame and a roller frame connected to one another. A bladder on the shoe frame is capable of being inflated from a deflated condition to an inflated condition. A fluid conduit is connected to the bladder for introducing fluid under pressure to inflate the bladder from the deflated condition to the inflated condition. At least a first roller is mounted on the roller frame. 
   According to one feature of the present invention a first section of the shoe frame is removable and a second section of shoe frame is capable of detachable attachment to the shoe frame for replacing the first section. Sections of different sizes and shapes maybe utilized to accommodate sewer pipes of different dimensions. 
   The method of the present invention comprises taking the frame assembly and inserting the shoe frame into the pipe passageway through the pipe end to an inserted position wherein the shoe frame is at least partially within the pipe passageway and the roller frame and the roller are positioned outside the pipe. The bladder is inflated to its inflated condition whereby the shoe frame and the bladder retentively engage the pipe walls and hold the shoe frame and the roller frame against movement within the pipe. A flexible cable is then fed around the roller and into the passageway whereby the flexible cable has a first segment on one side of the roller and outside the pipe passageway and a second segment on the opposite side of the roller within the pipe passageway. 
   When different sizes of sewer pipe are encountered, the shoe frame includes a first removable section. The method comprises removing the first removable section and replacing it with a second removable section having a second size that fits the cross-sectional size of the pipe passageway. 
   According to another feature of the invention the method comprises positioning the roller so that it prevents the flexible cable from coming in contact with a pipe end. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the apparatus of the present invention. 
       FIG. 2  is a sectional view of a sewer pipe and manhole, showing the apparatus of the present invention in place with the shoe frame within the sewer pipe. 
       FIG. 3  is a sectional view taken along line  3 — 3  of FIG.  2 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the drawings the numeral  10  generally designates the apparatus of the present invention. Apparatus  10  includes a frame assembly  12  which is comprised of a shoe frame  14  and a roller frame  16 . The roller frame  16  includes a first roller frame side  18  and a second roller frame side  20 , both of which are identical in construction. The roller frame sides  18 ,  20  are connected at their upper ends by a horizontal web  22 . Each of the roller frame sides  18 ,  20  includes a horizontally extending member  24 , a vertically extending member  26 , and a curved member  28 . Extending from the lower end of the curved member  28  is a horizontal connecting member  30 . Three rollers  32  are positioned along the curved member  28  and are rotatably mounted between the two roller frames  18  and  20  for pivotable movement about three roller axes  34 . A fluid nipple  36  is mounted on the web  22  and includes a fluid hose  38  connected thereto. The lower end of nipple  36  is connected to a fluid conduit  40 . 
   The shoe frame  14  includes a bladder  42  which is inflatable from the deflated position shown in  FIG. 2  to the inflated position shown in FIG.  3 . The bladder is mounted on a bladder support plate  44 . A curved plate  46  includes upstanding legs  48  which are attached to the horizontal connecting members  30  of the roller frame  16 . Bolts  50  and nuts  52  make this connection. The bottom surface of the curved plate  46  is covered by a rubber layer  54  which provides a protective surface for the curved plate  46 . While rubber is the preferred material for use for layer  54 , other materials maybe used so long as they are softer than the curved plate  46 . 
   Extending upwardly from the web  22  is a socket  56  which has threaded therein a vertical pole  58 . 
   Referring to  FIG. 2  a manhole includes manhole walls  60  and a manhole bottom  62 . A sewer pipe  63  includes a sewer pipe wall  64  and a sewer pipe end  66 . Often the end  66  of the sewer pipe is jagged or sharp and it is important to protect cables that are inserted into the sewer pipe from contacting or scraping against this sharp edge. The sewer pipe  63  includes a sewer pipe passageway  68  having an elongated sewer pipe axis  70 . The manhole includes a vertical manhole axis  72 . 
   A flexible cable  74  is shown having a first cable segment  76  above the rollers  32  and a second cable section  78  horizontally extending into the sewer pipe  63 . 
   In operation, the threaded pipe  58  is used to lower the apparatus  10  into a manhole and to place the shoe frame  14  inside the sewer pipe  63  as shown in FIG.  2 . Then pressurized fluid is introduced to the bladder  42  through the hose  38 , the nipple  36  and the conduit  40 . This causes the bladder  42  to inflate to the position shown from its deflated position shown in  FIG. 2  to its inflated position shown in FIG.  3 . As can be seen in  FIG. 3 , the bladder  42  tightly embraces the upper portion of the sewer pipe  63 . At the opposite side of the shoe frame  14  the curved plate  46  and the rubber layer  54  are pressed against the walls  64  of the sewer pipe  63 . This tightly places the shoe frame  14  and the roller frame  16  in position with the shoe frame  14  located within the sewer pipe  63 . 
   Next the cable  74  is trained around the rollers  32  in the manner shown in FIG.  2 . In this position the horizontal portion  78  of the cable  74  is within the sewer pipe  63  and the upstanding portion  76  of the cable  74  is on the opposite sides of the rollers and extends upwardly within the manhole. 
   Often, tension must be placed on the cable or hose  74 . During this tension, a considerable amount of stress is placed upon the roller assembly  10 . However, because the bladder  42  is expanding to tightly hold the shoe frame  14  within the sewer pipe  63 , the tension in the cable  74  does not dislodge or move the apparatus  10 . It should be noted that the rollers  32  provide a smooth bending of the cable  74  from its vertical section  76  to its horizontal section  78 . Furthermore, the rollers  32  hold the cable  74  away from the sharp edges the ends  66  of the pipe  64 . 
   Different sizes of sewer pipe  63  may be encountered. In order to accommodate these various sizes, the bolts and nuts  50 ,  52  may be removed and the legs  48  and the curved plate  46  removed from the shoe frame  14 . In order to accommodate a larger diameter pipe  63  a second curved plate  46  is provided with legs  48  that are longer. This second plate may then be bolted in place on the shoe frame so as to accommodate a pipe  63  of larger diameter. Similarly a pipe  63  of smaller diameter can be accommodated by using a curved plate  46  having shorter legs  48 . It is also possible to vary the curvature of the curved plate  46  to accommodate sewer pipes of differing diameters. 
   While three rollers  32  are shown, it is possible to use fewer than three or more than three without detracting from the invention. It is also possible to use inflating fluid for the bladder  42  that is either liquid or gas. 
   In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in the form and the proportion of parts as well as in the substitution of equivalents are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of the invention as further defined in the following claims.