Abstract:
A head sprocket assembly and sprocketless tail roller assembly for a pontoon track drive system wherein the sprocket assembly and tail roller is fitted with a plurality of support rings for straightening the track&#39;s elongated cleats attached to a plurality of chains passing lengthwise around the pontoons.

Description:
This invention is a continuation in part of previous application Ser. No. 09/908,027 filed Jul. 18, 2001, now U.S. Pat. No. 6,482,053, currently pending, the specification of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the track drive and tail sprocket assemblies and more particularly to the deletion of sprockets on the tail sprocket assembly and the adaptation of ring supports to the drive and tail sprocket assemblies for straightening bent cleats. 
     2. General Background 
     Excavating equipment used in wetlands is equipped with pontoons fitted with two or more runs of roller chains having plurality of elongated bar cleats attached to the chains. The chains are threaded lengthwise around head and tail sprocket assemblies located at each end of the pontoons. The head and tail sprocket or roller assemblies are generally fitted with sprockets, thereby providing a guide path for the chains to pass around the roller assembly. 
     Since such wet land vehicles operate in a semi-submerged condition in mud and water they often encounter a great deal of unseen debris such as rock, limbs and stumps. This debris often bends the elongated cleats extending between the chains or becomes trapped between the pontoon and the roller assemblies. When the debris is trapped it tends to be pulled into and pinched between the chain and the sprocket teeth, often breaking the chain. Downtime due to bending of the cleats and breaking of chains is expensive and a constant irritation to the operators. 
     It is an object of the instant invention to provide a means for straightening the cleats each time they pass over the roller assemblies. 
     It is also an object of the invention to provide a tail roller assembly without sprockets, thereby eliminating the possibility of feeding debris between the chain and sprocket teeth. 
     SUMMARY OF THE INVENTION 
     The present invention discloses a head sprocket assembly and sprocketless tail roller assembly for a pontoon track drive system wherein the sprocket assembly and tail roller is fitted with a plurality of support rings for straightening the track&#39;s elongated cleats attached to a plurality of chains passing lengthwise around the pontoons. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a further understanding of the nature and objects of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which, like parts are given like reference numerals, and wherein: 
     FIG. 1 is an isometric view of the head chain roller assembly with chains mounted to a pontoon; 
     FIG. 2 is an isometric view of the head chain roller assembly mounted to a pontoon; 
     FIG. 3 is a cross section view of the head chain roller assembly; 
     FIG. 4 is a cross section view of an alternate embodiment of the head chain roller assembly 
     FIG. 5 is an isometric view of the drive sprocket assembly; and 
     FIG. 6 is a cross section view of the drive sprocket assembly taken along sight line  6 — 6  seen in FIG.  5 ; 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Looking first at FIG. 1, we see the tail roller assembly  10  with a pair of chains  12  supporting elongated channel cleats  14  spanning the two endless chain runs extending lengthwise along the pontoon  16  and passing around the tail roller assembly  10 . 
     As seen in FIG. 1, the tail chain roller assembly  10  is fitted with a toothless chain guide  18  adjacent each end of the roller assembly  10  and a plurality of support rings  20  located there between as shown in FIG.  2 . As further seen in cross section in FIG.  3 ,the sprocketless roller assembly  10  is an elongated tube or drum assembly  22  fitted with end caps  23  and bushings  25  and supports at each end by stub shafts  27  and bearings  29 . The roller chains  12  are guided around the roller drum  22  by the chain guide  18  comprised of rings  24  attached to the drum assembly  22  and located either side of the chains  12 . As seen here in cross section, the support rings  20  are also attached to the roller drum assembly  22  and are located at intervals intermediate the chain guide rings  24 . The support rings  20  may have a rolled channel or box configuration or may simply be tubular rings  28  as seen in FIG.  4 . The rings  24  may be constructed by fabrication such as from a pair of disks with a band spanning the disk or by rolling structural shapes such as channel, box or round tubing. The rings may also be made from a polymeric and keyed to the roller drum assembly  22  or be a series of disk attached in parallel to produce the same effect. In any case, the support rings  20  or  28  are sized to be the same height as the roller chain  12  and the approximate the height of the polymeric guides  30  attached to the cleats  14  serving as guides along the channel guide ways  32  seen in FIG.  2  and further providing alignment and additional cleat support while passing around the head roller drum  22 . The rings  20  provide even support for the cleats  14  and tend to straighten any bent cleats as they pass over the sprocketless roller assembly  10 . 
     As seen in FIG. 5, the drive sprocket assembly  35  is located in a notched portion  34  of the pontoon  16  in a manner whereby the drive motor  38  and its housing  36  is facing the outboard side of the drive assembly and pontoon  16  in the manner shown, thereby protecting the drive motor  38  from any possibility of damage in cases where operating portions of the equipment attached to a pair of the pontoons  16  passes between the pontoons. 
     The drive assembly  32  seen in FIG. 5 may be configured whereby a pair of sprockets  40  is secured to a drum  42  seen in FIG.  6 . In this case a sprocket  40  is located at each end of the drum  42  and the drum may also be dividable at the center by a flange coupling  44 , in which case the outer diameter of the flanges of the coupling  44  may be such that they are equal to the distance between the cleats  14  and the drum  42  established by the combined height of the roller chain  12  and the sprocket roller root depth to drum dimension thereby providing a central support for the cleats  14  as they pas over the head drive assembly. Rings  46  similar to items  20  or  28  adjusting for the difference in height may be installed ion each side of the flange  44 . The polymeric guides  30  may also utilize the support rings  46  to help guide the cleats around the drive assembly  32 . 
     Rings  20  or  28  and  46  provide straightening of bent cleats  14  and thus prevent misalignment of the chains  12  and broken cleats. 
     Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in any limiting sense.