Tubular Guard for Track Roller Frames and Method for Making the Same

Track roller frames for track-type vehicles, such as crawler tractors, comprise a pair of track roller frames pivotally mounted on either side thereof. Such frames must constitute a rugged construction exhibiting a high degree of structural integrity since they are adapted to support the vehicle on a plurality of track rollers rotatably mounted thereon. The track roller frame further mounts an idler on a forward end thereof and a recoil mechanism and attendant mechanisms thereon. Typical track roller frames of this type are disclosed in U.S. Pat. No. 3,336,087 and U.S. Patent application Ser. No. 428,092, filed on Dec. 26, 1973, by Gary D. Blomstrom et al. for "Combined Integral Component Enclosure and Track Roller Frame", both assigned to the assignee of this application.

An object of this invention is to provide an improved and non-complex track roller frame which exhibits a high degree of structural integrity when placed in operation. Another object of this invention is to provide an economical method for making a tubular guard of the track roller frame expeditiously and from a pair of substantially identical members.

The tubular guard, adapted to rotatably mount a plurality of track rollers thereon, comprises a pair of longitudinally disposed members secured together at upper and lower edges thereof disposed medianly of the guard and extending substantially the full length thereof. The method is accomplished by initially forming each of the members with a generally upright first wall portion and a second wall portion extending inwardly from the first wall portion and by thereafter bending and securing the respective first and second wall portions together, preferably by a pair of longitudinally extending upper and lower welds.

Other objects of this invention will become apparent from the following description and accompanying drawings wherein:

FIG. 1 is a side elevational view of the undercarriage of a track-type vehicle having the improved track roller frame of this invention incorporated therein; and

FIGS. 2 and 3 are sectional views taken in the direction of arrows II--II and III--III in FIG. 2, respectively, but with portions of attendant mechanisms supported on the track roller frame deleted for clarity purposes.

FIG. 1 illustrates an endless track assembly 10 for a track-type vehicle which is substantially disclosed in above-references U.S. Patent application Ser. No. 428,092. In particular, the endless track assembly comprises an endless track 11 adapted to be driven by a drive sprocket 12 rotatably mounted on a main frame 13 of the vehicle. A rearward end of the track roller frame 14 is pivotally mounted on the main frame by a pivot shaft 15 whereas a forward end of the track roller frame is supported on the main frame by an equalizer bar mounting 16.

A plurality of track rollers 17 are rotatably mounted on the track roller frame which further rotatably mounts an idler 18 on a forward end thereof. The idler is rotatably mounted on a shaft 19 having each of its lateral ends disposed in an elongated lost motion slot 20 and suitably connected to a recoil mechanism 21. As shown in FIGS. 1 and 3, a bracket 22 is releasably attached to each end of shaft 19 by cap screws 23 to position the idler laterally relative to frame 14.

The track roller frame comprises a tubular guard 24 substantially constituting a pair of longitudinally disposed and substantially identical members 25 and 26 secured together by upper and lower welds 27 and 28, respectively (FIG. 2). The members comprise laterally positioned first wall portions 29 and 30 having their free upper edges secured together at common weld 27 and a pair of second or bottom wall portions 31 and 32 having their free lower edges secured together at common weld 28. The welds are disposed medianly of guard 24 and extend substantially the full length thereof to provide substantially all of the securance therebetween.

As further shown in FIG. 2, members 25 and 26 have a pair of longitudinally extending support portions 33 and 34 integrally formed thereon, respectively. The elongated support portions extend downwardly on the outboard sides of the guard below wall portions 31 and 32 and coextensively of the guard. The end of the shaft of each track roller assembly 17 is suitably attached to an underside of a respective support portion by a bracket 35 and cap screws 36. Referring to FIG. 3, a bracket 37 is secured on each end of idler shaft 19 and has a hook portion 38 which engages beneath a bearing surface 39, formed on each of the members 25 and 26 to aid in retaining the idler in position thereon.

The method for making guard 24 will now be described. Referring to FIG. 2, member 25, for example, is suitably roll-formed or the like to comprise a generally upright and flat first wall portion 29', second wall portion 31 and downwardly projecting support portion 33 which is generally coplanar and coextensive with respect to the first wall portion. Member 26 is formed in a like manner.

First wall portion 29' is then suitably bent into its final arcuate configuration 29 and into overlying and vertically spaced relationship relative to first wall portion 31. The adjacent edges of wall portions 29 and 30 are then secured together by common weld 27 whereas second wall portions 31 and 32 are secured together at their edges by common weld 28. Either prior to such welding or subsequent thereto, the various cutouts and slots for accommodating actuating mechanisms of the endless track assembly may be formed in the guard.

For example, slots 20 are suitably formed through the sidewalls of the guard to accommodate the ends of shaft 19 whereas a suitably formed slot 40 is formed medianly and longitudinally at a forward end and towards an aft end of the guard to accommodate reciprocal idler 18 therein. Access openings (not shown) may be suitably formed through the top wall of the guard and covered by releasable covers 41 to facilitate servicing of recoil mechanism 21. A pillow block 42 is suitably secured on an aft end of the guard to attach the track roller frame to pivot shaft 15 by means of a cap 43. The remaining mechanisms, including equalizer bar mounting 16, track roller assemblies 17 and a carrier roller assembly 44, are then suitably secured in place.