I was going to post these in the digging over drive motors thread when the subject of chains and pins and bushes came up and never did quiet get around to it. I thought that some of you may have never seen the tracks on a large excavator, they(maybe not all) don't have track chains and grouser plates, just one track segment and two pins. The pics will show better than I can describe. The drive thingamajig is called a tumbler. These photos are of a Hitachi 5500, the pic of the top of the track I had to hold the camera up over my head to get it. :cool2
Hi diggerop, Good shots, thats a lot of steel. An 1800 is the largest ex. I have worked, it was loading Cat 776 belly dumps & 777 end dumps.
That is similiar to a crane undercarriage like a Link Belt or an American.
I think the EX1900 is the biggest Hitachi with a traditional chain/shoe undercarriage. Go bigger and they all have this style which is typical on cranes and massive machines. I guess a chain gets too "tall" and fabricated shoes so wide they couldn't hold the bending stresses generated.