Abstract:
Disclosed herein is an improved rotary drain cleaning machine having an improved support structure that prevents walking of the machine when in use. The machine is supported upon two rear mounted wheels and a forward pedestal.

Description:
PRIORITY 
       [0001]    This application is a continuation of prior, co-pending application Ser. No. 11/471,423, filed Jun. 20, 2006, and entitled “Sewer Cleaning Machine”. The disclosure of application Ser. No. 11/471,423 is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention generally relates to sewer cleaning machines having a belt driven drum, or basket, which typically stores therein, and drives, a pipe cleaning cable or “snake.” More particularly the present invention teaches a unique and novel support structure for eliminating the classic wobble, or walking tendency, of prior art machines when operating. 
       PRIOR ART 
       [0003]    Typically prior art sewer cleaning machines comprising a belt driven drum, or basket, which typically stores therein and drives a pipe cleaning cable or “snake,” employ a mobile support system having a pair of spaced apart rear wheels and a forwardly positioned support generally comprising a lateral, floor engaging bar or a pedestal foot. The prior art wheels typically comprise a center disc having a pneumatic, or semi-pneumatic, elastomeric tire mounted thereon. For example see U.S. Pat. No. 5,309,595 issued to Salecker et al. 
         [0004]    During operation, the combined weight of the drum, with approximately 100 to 200 lineal feet of cable wrapped therein is approximately 135 pounds. As the cable is wrapped within the drum it will wrap in an unsymmetrical manner thereby creating an “off-center,” or eccentric center of mass within the rotatable drum or basket. Thus as the drum, or basket, is rotated, during operation of the machine, the eccentricity of the loaded cable within the drum, or basket, causes the machine to “wobble” side to side, whereby the machine will “walk” across its supporting surface. 
         [0005]    One attempt to cure the machine walking problem is proposed by Babb et al. in U.S. Pat. No. 5,031,276 wherein Babb et al. suggests use of a retractable wheel stabilizing means that is lowered into place making contact with the machine&#39;s supporting surface thereby slightly lifting the wheel above the supporting surface. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    Although the mechanics of the “walking” problem is not fully understood it is believed that as the eccentric center of cable mass rotates asymmetrically about the drum axis of rotation a centrifugal force, acting away from the axis of the drum rotation is created. 
         [0007]    Facing the front of the drain cleaning machine and using the points of the twelve hour clock as a reference, as the eccentric centrifugal force is directed downward at the six o&#39;clock position the centrifugal force is shared by both wheels and the forward surface engaging support. However, as the centrifugal force rotates toward the nine o&#39;clock position the centrifugal force imparts a moment about the approaching wheel upon the machine. The imparted moment now tends to compress the approached pneumatic, or semi-pneumatic, tire and further causes the expansion of the opposite pneumatic, or semi-pneumatic, tire thereby causing the machine to rock, or wobble, sideways and thereby reduces the frictional engagement between the opposite tire and supporting surface. Thus the pneumatic or non-pneumatic tires are assisting the rocking, or wobbly, motion of the machine rather than resisting the motion. 
         [0008]    As the eccentric centrifugal force passes the nine o&#39;clock position and approaches the twelve o&#39;clock position, the centrifugal force tends to lift the wheel just passed and compress the opposing wheel. At the twelve o&#39;clock position the eccentric centrifugal force tends to lift both wheels from the supporting surface. It is believed that by this action upon the compressible support wheels that a rocking, “wobbling” motion is the cause of the machine “walking” across the supporting surface. 
         [0009]    It has been discovered that by replacing the prior art pneumatic and/or semi-pneumatic tires with a relatively incompressible, solid elastomeric tire, the cyclic expansion and compression of the pneumatic, or semi-pneumatic, tires is eliminated and the solid tires now resist the side to side rocking, or “wobble,” of the machine rather than assisting it thereby preventing the walking phenomena experienced in the prior art machines 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  presents a perspective view of a belt driven, rotating drum, drain cleaning machine embodying the present invention. 
           [0011]      FIG. 2  presents an exploded perspective of the belt driven rotating drum drain cleaning machine shown in  FIG. 1 . 
           [0012]      FIG. 3  presents a crossectional view taken along line  3 - 3  in  FIG. 2 . 
           [0013]      FIG. 4  presents a crossectional view taken along line  4 - 4  in  FIG. 2 . 
           [0014]      FIG. 5  presents a crossectional view taken along line  5 - 5  in  FIG. 5 . 
           [0015]      FIG. 6  present a crossectional view similar to that of  FIG. 3  illustrating an alternate embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]      FIGS. 1 and 2  present a typical belt driven drum-type drain cleaning machine  10 . Drain cleaning machine  10  comprises a base frame  11 . Supporting thereon an electric driving motor  12 , a cable storage drum  14  driven by way of an endless drive belt  16  typically wrapping about the circumference of drum  14  and drive pulley  18  attached to the motor output shaft. A safety shield, or cover, typically encloses the motor output shaft and drive pulley  18  as illustrated. 
         [0017]    As illustrated, base frame  11  includes a pair of rear support wheels  25 A and  25 B rotatingly mounted upon axle  26  affixed to frame  11  as illustrated. Pedestal  42  extends vertically and is affixed to base frame  11 , as illustrated in  FIGS. 1 and 2 . mounted atop pedestal  42  is cable feeder head assembly  36 . Cable  38  typically extends from drum  14  through cable guide tube assembly  39  and feeder head assembly  36 . Attached to the end of cable  38  is a typical sewer cleaning claw  48 . 
         [0018]    As illustrated in  FIG. 3 , unitary wheel assembly  25  basically comprises a cast aluminum center disc  34 , having an axially extending hub  35 , an axially extending tire mounting rim  32  and a solid elastomeric tire  40 . Solid tire  40  is preferably made of Styrene Butadiene Rubber (SBR) compound specifically having a Shore Durometer hardness of 75 and a thickness of one half of an inch adhesively affixed to wheel rim  32  or heat shrunk thereon. 
         [0019]    Alternatively, as illustrated in  FIG. 6 , wheel assembly  25  may comprise a cast aluminum center disc  55 , having an axially extending hub  56  and an axially extending tire mounting rim  52  with a multiplicity of integral rim reinforcing spokes or webs  54 , extending radially from hub  56  to rim  52 , and a SBR tire  50  specifically having a Shore Durometer hardness of 75. Center disc  55 , rim  52 , hub  56  and webs  54  are preferably cast aluminum. 
         [0020]    Referring to  FIGS. 4 and 5 , pedestal  42  comprises a “U” shaped metal channel approximately eleven inches high, having an approximately five inch web and a two and one half inch flange. A metal plate  46  is welded across the bottom, of the channel, between the opposing flanges. A one inch thick, elastomeric shoe, preferably comprising a black Neoprene rubber composition having a Shore Durometer hardness of 75, shoe  44  is adhesively affixed to the bottom of pedestal  42  as illustrated in the figures. 
         [0021]    Although the specific hardness of tires  40  and shoe  44  is a Shore Durometer of 75, it is believed that an acceptable hardness may lie between a Shore Durometer of 70 to 80. 
         [0022]    A parking brake  50  is further provided, the operational mechanism of which is not shown as it comprises kinematic levers, well known within the industry, to forcibly engage tire  40  thereby preventing the drain cleaning machine from freely rolling on an uneven surface. 
         [0023]    While I have described above the principles of my invention in connection with a specific preferred embodiment it is to be clearly understood that this description is made only by way of example and not as a limitation of the scope of my invention as set forth in the accompanying claims.