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CROSS REFERENCE FOR RELATED APPLICATION 
   Applicant claims benefit of a provisional application filed on Nov. 11, 2002, Serial No. 60/425,405. Specific references to this document is requested. 

   BACKGROUND OF THE INVENTION 
   This invention relates to cleaning the inside surface of pipes. Although this invention is useful for other pipes, it is primarily designed for scrubbing the pipe of agriculture irrigation wells. Debris often attaches to the inside diameter of the pipe. Even if the pipe bore is not reduced substantially, the rough surface of the pipe hinders the free flow of water, therefore requiring extra power of the pumps to force the water to the surface of the ground. 
   Previously, tools for cleaning pipes have been patented. For example, Kear U.S. Pat. No. 354,78, Dec. 14, 1886, describes a device for cleaning water pipes. Reed, et al; U.S. Pat. No. 1,677,050, Jul. 10, 1928 shows a device called a parafant cutter which has helical rods which bow outwards to clean the pipes. Walbrohl U.S. Pat. No. 1,837,931, Dec. 22, 1931 shows a brush of steel wires which are positioned around a cylinder and are separated by helical springs. 
   Dana U.S. Pat. No. 2,415,729 , Feb. 11, 1947 discloses a series of brushes for the cleaning of oil wells. Dana, like Walbrohl, discloses the brush as held by a line to the top of the well and is pulled downward by a weight attached to the bottom of the brush structure. Claiborne, U.S. Pat. No. 3,176,771 scrapes mud-cake from the side of a bore. Girard, U.S. Pat. No. 3,460,180, Aug. 12, 1969 discloses a scrapper for scraping the inside of pipes. Rosseau, U.S. Pat. No. 3,952,359, Apr. 27, 1976 shows a street sweeper brush which holds the bristle to an inside metal U-shaped holder which is similar to the holding of the brushes of this application. 
   BRIEF DESCRIPTION OF THE DRAWINGS 
   Bristles of cylindrical brushes are clustered together to scrub debris from the interior surface of a pipe. With the bristles clustered together, the bristles become loaded with debris. The loaded bristles are loosened and scattered to permit the debris to drop from the scattered bristles, as desired by the operator. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an incomplete cross section of the scrub unit in a vertical pipe with the brushes in the condition they would be in when the unit was moving downward within the pipe. 
       FIG. 2  is an incomplete sectional view illustrating the conditions of the scrub unit when the unit was not being forced upward or downward and therefore the brushes are expanded to a spread condition where the bristles are spaced wider apart than when in the scrub position such as shown in  FIGS. 1 and 3 . 
       FIG. 3  shows the condition of the scrub unit as the system was moving upward by pulling the suspending cable upward. 
       FIGS. 1 ,  2  and three do not show the channel with the bristles attached. 
       FIG. 4  is a illustration of a brush dissembled from the rod showing the spacing of the channel loops when there is no external pressure. 
       FIG. 5  is similar to  FIG. 4  showing a brush in the fully collapsed position with each channel loop in contact with the adjacent loop. 
       FIG. 6  is a cross section of the channel showing the clamping of the bristles within the holder and the position of a wire in this part. 
       FIG. 7  is a section of a view taken on line  7 — 7  of  FIG. 6 . 
   

   CATALOG OF ELEMENTS 
   As an aid to correlating the terms to the exemplary drawing(s), the following catalog of elements is provided: 
   
     
       
             
             
             
           
         
             
                 
                 
             
           
           
             
                 
                8 
               pipe 
             
             
                 
               10 
               scrub unit 
             
             
                 
               12 
               rod 
             
             
                 
               14 
               bolt 
             
             
                 
               16 
               nut 
             
             
                 
               18 
               washer 
             
             
                 
               20 
               brush 
             
             
                 
               22 
               bristles 
             
             
                 
               24 
               channel 
             
             
                 
               25 
               cable 
             
             
                 
               26 
               metal 
             
             
                 
               28 
               wire 
             
             
                 
               30 
               eye 
             
             
                 
               LE 
               Axial length extended 
             
             
                 
               LC 
               Axial length compacted 
             
             
                 
                 
             
           
        
       
     
   
   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A scrub unit  10  includes rod  12  and one or more brushes  20 . 
   The scrub unit  10  is shown in  FIG. 1  as it would appear after going into the well where the scrub unit  10  is moving downward by the weight of rod  12 . Individual brushes  20  are carried upon rod  12 . Rod  12  is preferably an iron rod about 2′ in diameter when the scrubber is to be used for a 6′ pipe. For one scrub unit  10  there would be a total of about three to five brushes  20 . The top of the rod has an eye  30  for attaching cable  25 . The bottom of the rod  12  is threaded so that an additional metal rod could be attached to the bottom of the rod  12 . The additional rod could carry either brushes as does rod  12 , or it could be without brushes merely to give additional weight to the unit if such was required by the operator. A series of bolts  14  extend through the rod  12  and held by nuts  16  to keep the brushes  20  within a certain limit of travel up and down the rod. Bristles  22  on each brush  20  are in contact with the inner surface of pipe  8 . As the rod moves downward, each of the brushes  20  against the inner surface of the pipe  8  will cause washer  18  on the rod above the brush to move against the bolt  14  above the brush. The friction of the bristles on the brush will cause the brush to retract into a shorter compact length when moving vertically. The contacted bristles will efficiently scrub the interior of the pipe  8 . 
     FIG. 5  is a representation of the compacted brush  20  when the vertical movement causes each channel  24  loop to contact the adjacent channel  24  loop. This causes bristles  22  to bunch or cluster or move together. This cluster of bristles scrubs the pipe better than separated bristles. 
   After the scrub unit  10  has moved down a desired amount the rod  12  may be moved upward by cable  25  pulling it upward. As seen in  FIG. 2 , at this time of transition when the rod  12  first begins moving upward, the natural spring of the U-shaped metal channel  24  will tend to elongate, thus spreading the individual coils of the brush  20 .  FIG. 4  is a representation of the relaxed brush  20  when the reversed movement causes each channel  24  loop to spread away from the adjacent channel  24  loop. This causes the bristles  22  to scatter or move away from the other bristles. This scattering of the bristles  22  aids in releasing debris, thus preventing the bristles from becoming loaded with debris. At this time much of the debris that was attached to the bristle  22  of the scrubber unit  20  will come free. 
   With continued upward movement of rod  12  by reeling in the cable  28  it will be understood that each brush  20  would assume the position as shown in  FIG. 3 ; the brushes  20  would compact until the channels  24  were in contact bringing all the bristles  22  together as they scrubbed in the upward phase. 
   Although not critical, the expansion of the brush is about twice the axial length of the scrubber fully compressed. For example, one scrubber has a length extended of 5½ inches and length compacted of 3 inches. 
   The bolts  14  that extend through diametric holes in rod  12  are held in place by nuts  16 . The washer  18  as placed on the rod has an inside diameter of slightly more than the diameter of the 2″ rod, and an outside diameter of 3½ inches. One of the brushes  20  is placed on top of the washer  18 . A top washer  18  is placed above the brush. Another bolt  14  is attached with nut  16  to the rod  12 . 
   Brush  20  includes a helical metal spiral channel  24  of about 6 inches from top to bottom. The brush  20  has a diameter of slightly more than 6 inches to operate in a 6″ pipe. 
   The brush  20  has bristles  22  attached to the helical metal channel  24 . The channel is a springy coil having about eleven loops. 
   Each brush  20  when relaxed will have an axial extended length of about 6 inches. When a brush  20  is compressed with all eleven loops of channel  24  contacting the adjacent loop, it will have an axial compressed length of about 3½ inches. When the brushes  20  are on the rod  10  outside the pipe, they will have approximately three inch movement between the limiting bolts  14 . Referring to  FIG. 4 , which shows a brush  20  in the relaxed position, the channels  24  are formed in the helical spiral position and therefore have the loops of the spiral are separated. Also, there would be approximately  11  loops in the brush  20 . When they are pressed together, as seen in  FIG. 5 , the channels  24  would be adjacent and therefore the axial length of the brush is about 3½ inches. 
   Polypropylene bristles  22  are attached within the channel  24 . The diameter of the brusher is over 6 inches so that when it is cleaning the pipe the bristles have pressure contact with the walls of the pipe. 
   Referring to  FIG. 1 , showing the scrub unit  10  as it moves downward, the tips of the bristles  22  are pressured against the inside surface of the pipe  8 , which is rough with debris. This drags the brushes  20  along the pipe inside surface as the weight of the rod  12  force the brushes down. The weight of the rod  12  will push the washer  18  by the bolts  14  and nut  16 . The continued downward pressure of the weight of rod  12  will result in the compression of the brush  20  and the concentration of the bristles  22 . The continued downward movement scrubs the inside surface of the pipe  8 . 
   When the unit  10  is moved upward by the cable  28  attached to the eye  30 , the brushes would no longer have the weight of the rod against them, and therefore, they would expand. The spring resilience of the channels  24  would cause the brushes to expand. When the channels  24  are expanded it will aid in the removal of the debris from the bristles  22 . Referring to  FIG. 3 , it may be seen that as the unit is pulled upward as shown by the ‘U’ arrow, that the brushes  20  would be compressed by the friction on the inside pipe surface so that the brushes  20  would be pushed upward by the washer  18  because of the upward movement of the bolts  14 . 
   Therefore, it may be seen that by moving the rod  12  by the supporting cable  28  unit for a few feet upward and then permitting it to lower a few feet downward would scrub the inside surfaces of the pipe. Also, as it alternates between upward movement and downward movement there would be a repeated dispersing of debris from the bristles. 
   The bristles  22  and their attachment in channel  24  is shown in  FIG. 6 and 7 . The attachment is formed with bristles made from crimped red polypropylene stock measuring 0.8 mm thick×1.05 mm wide. The bristles  22  are looped around wire  25 . The wire with the bristles are clamped into the channel  24 . The channel  24  and the wire  25  are resilient. Since they are resilient they will tend to be a helix as illustrated in  FIG. 4 . This is to say unless an exterior force is put upon them the helical spiral of the channel will cause the brush  20  to be an extended axial length. However, when they are subject to an external force exerted along the axis of the helix they would be reduced into a compressed axial length. However, as stated when the external pressure is releases, the brushes expand into the extended axial length. 
   It will be understood that the embodiment of the invention as described here would be subject to many variations. Specifically, the rod  12  could be of various diameter and lengths depending upon the inside diameter of the pipe for which it would clean. Also, additional weights could be attached to the bottom of the rod. Also the rod could be suspended by a cable or could be suspended by tubing. In certain circumstances, two or more of the cleaning units  10  could be fastened together if this was the desire of the operator. Also, even if the rod  12  were designed to hold four brushes  20  it would be understood that it could be operated with one or two or three brushes as well as the full four brushes. 
   The embodiment shown and described above is only exemplary. I do not claim to have invented all parts, elements or steps described. Various modifications can be made in the construction, material, arrangement, and operation, and still be within the scope of my invention. The limits of the invention and the bounds of the patent protection are measured by and defined in the following claims. The restrictive description and drawing of the specific example above do not point out what an infringement of this patent would be, but are to enable the reader to make and use the invention.

Summary:
A cylindrical brush for scrubbing the inside surface of a pipe is made of bristles attached to a springy helix. The diameter of the brush is greater than the inside diameter of the pipe. When the brush is pushed through the pipe the helix collapses and compacts the bristles to scrub the surface. When the brush is released in the pipe, the helix expands and spreads the bristles; thereby aiding in release of debris collected on the bristles during the scrubbing.