Working Machine

Abstract

A working machine has a main frame structure which includes a pair of endless tracks, each track is entrained about track supporting devices mounted by a track sub-frame. The sub-frame includes inner and outer members interconnected by cross members. The inner and outer members are arranged side by side and mounting at or adjacent upper edges thereof, at least one upper track support device between the members. The inner and outer members mount at or adjacent lower edges thereof, at least one lower track supporting device between the members. The inner and outer members and cross members of at least one of the track sub-frames is a monolithic casting.

1 . A working machine having a main frame structure which includes a pair of endless tracks, each track being entrained about track supporting devices mounted by a track sub-frame, the sub-frame including inner and outer members interconnected by cross members, the inner and outer members being arranged side by side and mounting at or adjacent upper edges thereof, at least one upper track support device between the members, and the inner and outer members mounting at or adjacent lower edges thereof, at least one lower track supporting device between the members, the inner and outer members and cross members of at least one of the track sub-frames being provided by a monolithic casting.  
   
   
       2 . A machine according to  claim 1  wherein the monolithic casting is provided in a weldable casting material.  
   
   
       3 . A machine according to  claim 2  wherein the track sub-frame or frames are attached to the remainder of the main frame structure by welding.  
   
   
       4 . A machine according to  claim 1  wherein the cast inner and outer members have along their respective upper and lower edges, recesses for receiving mountings for the track supporting devices.  
   
   
       5 . A machine according to  claim 4  wherein at least some of the track supporting devices each includes a roller carried on a spindle.  
   
   
       6 . A machine according to  claim 4  wherein the upper and lower edges of the inner and outer track sub-frame members include further recesses which lighten the monolithic casting.  
   
   
       7 . A machine according to  claim 1  wherein at least one of the inner and outer track sub-frame members provides a mounting for a track motor which in use drive a track drive sprocket located between the inner and outer members.  
   
   
       8 . A machine according to  claim 7  wherein the track motor mounting includes an opening in the at least one track sub-frame member at or towards an end of the track sub-frame member which extends longitudinally of the machine beyond the corresponding end of the other track sub-frame member.  
   
   
       9 . A machine according to  claim 1  wherein at least one of the inner and outer track sub-frame members provides a mounting for a track tensioning mechanism which includes a track tensioning element which is resiliently biased in a direction so as to maintain a desired tension in the track entrained about the track supporting devices.  
   
   
       10 . A machine according to  claim 1  wherein the main frame structure includes a main frame part which lies between the pair of track sub-frames.  
   
   
       11 . A machine according to  claim 10  wherein the main frame part includes a central portion for supporting a part of a slewing mechanism, the machine including an upper frame structure which is rotatable about a generally upright axis relative to the main frame structure, by the slewing mechanism.  
   
   
       12 . A machine according to  claim 11  wherein the central portion of the main frame part is attached to each of the track sub-frames by connecting arms.  
   
   
       13 . A machine according to  claim 11  wherein the central portion of the main frame part is attached to each of the track sub-frames by connecting arms.  
   
   
       14 . A machine according to  claim 12  or  claim 13  wherein the connecting arms are provided by elements fabricated in a material which is weldable to the track sub-frames.  
   
   
       15 . A machine according to  claim 14  wherein the pair of connecting arms are welded to the inner track sub-frame members of the track sub-frames, and to the central portion of the main frame part.  
   
   
       16 . A machine according to  claim 15  wherein the central portion is cast in steel.  
   
   
       17 . A machine according to  claim 14  wherein the inner of the track sub-frame members of the track sub-frame monolithic casting includes for each connecting arm, one or more integral formations which extend inwardly of the machine towards the central portion, the connecting arms being welded to the integral formations.  
   
   
       18 . A method of making a working machine having a main frame structure which includes a pair of endless tracks, each track being entrained about track supporting devices mounted by a respective track sub-frame, the method including making at least one of the track sub-frames by providing a monolithic casting including inner and outer track sub-frame members arranged side by side with there being integral cross members interconnecting the track sub-frame members.