Abstract:
A frame for supporting a track of a track-laying vehicle includes a pair of lower longitudinally extending members having surfaces disposed to prevent sideways movement of the track and for supporting the track shoes in the event that the track begins to twist from working loads imposed thereon.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to frames for supporting tracks of track-laying tractors and more particularly relates to portions of such frames which are adapted to prevent undue damage to the tracks. When track-laying vehicles such as those commonly used in forestry and excavating are operated, it sometimes happens that the track passes over obstructions such as bumps, logs and rocks or the like resulting in single track shoe loading which is sometimes in the nature of bending loads that cause damage to the track shoes and/or the remainder of the track. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided a novel frame for supporting a track of a track-laying vehicle and more particularly there is provided structure for minimizing damage to the track and track shoes during single track shoe loading. 
     A broad object of the invention is to provide track-laying structure for supporting one or more of the track shoes after the track has undergone a predetermined amount of twist. 
     A further object of the invention is to provide a track-laying support structure which will prevent the track from sliding sideways from rollers of the track assembly. 
     Another object of the invention is to provide track protecting structures which may be easily connected to and removed from the track support frame. 
     These and other objects will become apparent from a reading of the ensuing description taken in conjunction with the appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic left side elevational view of a typical track-laying vehicle with which the present invention is particularly adapted for use. 
     FIG. 2 is an enlarged view of a track support assembly shown in FIG. 1. 
     FIG. 3 is an enlarged sectional view taken along the lines 3--3 of FIG. 2 with parts omitted for the sake of simplicity. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, therein is shown an industrial vehicle 10 of a type commonly used for excavating or forestry harvesting work and with which the present invention is particularly adapted for use. Specifically, the vehicle 10 includes a superstructure 12 rotatably supported, in a manner conventional in the art, on an undercarriage 14. 
     The superstructure 12 includes a frame 15 which supports an engine (which is not shown) in an engine compartment 16 located at the rear of the frame. Supported at the forward end of the frame 15 is an operator&#39;s cab 18 located along the side of the rear end portion of a boom structure 20 having its rearend connected to the frame 15. The boom structure 20 would normally support excavating or forestry harvesting attachments (not shown) as is conventional. 
     The undercarriage 14 includes a main frame or carbody 22 including longitudinally extending right and left track support frames 24 of which only the left frame is shown and described herein for the sake of brevity. 
     As can best be seen in FIGS. 2 and 3, the track support frame 24 includes a longitudinally extending, inverted U-shaped main frame member 26 including right and left transversely spaced vertical walls 28 and 29, respectively, the walls 28 and 29 having lower horizontal edges 30 and 32, respectively. Right and left longitudinal mounting bars 34 and 36, respectively, are fixed, as by welding, to respective inner surfaces of the walls 28 and 29 and extend downwardly below the edges 30 and 32. A plurality of track support roller assemblies 38 are disposed centrally between the vertical walls 28 and 29 and are mounted on the bars 34 and 36 at longitudinally spaced locations. Supported at the rear of the main frame member 26 is a drive sprocket 40 and supported at the forward end of the frame member 26 is an idler wheel 42. 
     An endless track assembly 44 is entrained about the drive sprocket 40 and idler wheel 42 so as to define upper and lower runs 46 and 48. The track assembly 44 comprises an articulated link assembly including a plurality of links 50 hingedly or pivotally interconnected by pivot pin and bushing assemblies 52 and a plurality of track shoes 54 fixed to the links in a conventional manner, the shoes 54 extending transversely beyond the vertical walls 28 and 29 of the main frame member 26. As is conventional in the art, the pivot pin and bushing assemblies 52 are engaged by the respective teeth (not shown) of the drive sprocket 40 when the track 44 passes thereover. Further, it is to be noted that the pivot pin and bushing assemblies 52 of the lower run 48 of the track 44 engage the track support roller assemblies 38. 
     It is to be noted that the structure heretofore described is largely conventional and that the instant invention concerns the cooperation of structure to be described below with that which has already been described. 
     For the purpose of preventing damage to the track 44 when the latter is flexed by passing over a rock, stump, or other obstacles of that nature, right and left track guide and support members 56 and 58, respectively, are mounted on the track support frame 24. Specifically, the members 56 and 58 comprise welded structures respectively including vertical sections 60 and 62 having upper end portions disposed in embracing relationship to outer surface portions of the vertical walls 28 and 29 and having lower ends welded to respective horizontal sections 64 and 66, respectively, the horizontal sections 64 and 66 having respective inner edges 68 and 70 disposed adjacent to the ends of the pivot pin and bushing assemblies 52 of the lower run 48 of the track 44. Respectively welded to the vertical sections 60 and 62 at locations above the horizontal sections 64 and 66 are a plurality of horizontal tabs 72 and 74 which embrace downwardly facing horizontal mounting surfaces of the longitudinal mounting bars 34 and 36 and are secured to the bars 34 and 36 through means of a plurality of screw fasteners 80. For the purpose of rigidifying and maintaining parallelism between the track guide and support members 56 and 58, there is provided a plurality of spacer assemblies, the spacer assemblies each comprising a bolt 82 extending through the vertical sections 60 and 62 of the members 56 and 58 and having a tubular spacer member 84 received thereon and engaged with the inner surfaces of the vertical sections 60 and 62. 
     It will be appreciated that, during the operation of the vehicle 10, the tendency of track 44 to shift sideways relative to the support frame 24 is resisted by the pivot pin and bushing assembles 52 coming into engagement with the inner edges 68 or 70 of the track guide and support members 56 and 58. Further it will be appreciated that when the tracks of the vehicle 10 pass over an obstacle, such as a rock or log, individual loading of the track shoes 54 will occur and if an end portion of one of the track shoes 54 engages an obstacle being passed over by the vehicle 10, the engaged shoe 54 will rise only as far as permitted by the lower surfaces of the horizontal sections 64 and 66 of the track guide and support members 56 and 58, the forces imposed on the track then being transmitted to the frame 24 so as to prevent undue loading of the track shoe and damage that might occur as a consequence of such loading.