of fig3 the rear traction unit effectively defines means for supporting the ripper assembly against distortion during ripping operation while yet permitting the ripper assembly structure to be relatively light the ripper tips may be readily adjusted by the jacks 46 for ripping operation or disposition in a retracted position as shown in full lines in fig3 as desired referring now to fig4 another embodiment discloses a ripper assembly 60 carried by a connecting means 61 which connects first and second track type tractors in series tandem relationship a ripper 64 of the ripper assembly is adjustably positionable relative to and independently of the connecting means by adjusting means generally designated 65 comprising a jack 66 the connecting means 61 includes first second and third frames 67 68 69 respectively the first frame has a substantially 34 u 34 shape and has a pair of legs 70 71 extending longitudinally forwardly from a transverse portion 72 the first frame stradles the rear portion of the first tractor 62 and is connected to the first tractor by suitable pivot pins one shown at 73 the third frame is also substantially 34 u 34 shaped and has a pair of legs 74 75 extending longitudinally rearwardly from a transverse portion 76 the third frame straddles the front portion of the second tractor 63 and is connected to the second tractor by suitable pivot pins one shown at 77 the forward end of the second.