I agree with Deas, its for a tandem pusher C frame.

"Deas wrote:

Hi, Philc.
I must admit that I have not seen as many tree pushers mounted this way as I have seen mounted to clevises welded on near the rear end of the push arms of straight blades or the C-frames of angle blades. That said, this method of mounting to an extra trunnion seemed to be more common in the heavy timber country in the South-west of Western Australia than anywhere else, at least from my observations.

OK I have never seen one mounted to the rear trunion. Do you have any pictures?

"Deas wrote:

I have also seen them used for a 'toolbar' of sorts with a cable control arrangement attached to the rear roof of a heavy timber canopy. BUTTTT, that rear-mounted ripper would mean either it would hafta be removed or a toolbar would hafta be a LONG way behind the tractor. And what would control it?

What you are looking at in your photo is NOT a 'toolbar'. It is a rear push frame for working with 2 tractors tandem push-loading scrapers. It was designed thisaway to avoid having the force from the rear tractor go into the mainframe of the front one and then have to be transferred out to the track frames. This arrangement put the force from the rear tractor directly onto the push frame of the front tractor.

Just my 0.02.

What I meant by rippers is not the deep rippers normally behind a dozer but smaller agricultural rippers etc. I never said the photo was of a toolbar just as an example of what can be attached to the rear trunions. Poor choice of words on my part but I was typing the reply at work on my iphone:)

Regards

Phil

Hi, Catsilver.
I didn't say that the trunnions on Westoz48A's machine were for a tandem pusher frame. I said they were most likely the mounts for a tree pusher bar. What I said was a tandem pusher frame was the C-frame behind the Cat in the photo that Philc posted a link to - this link.

www.fao.org/docrep/x5373e/x5373e0g.jpg

I also suspect that the tractor in the photo at Philc's link is/was a Caterpillar-modified 2U D8 Pusher tractor if the decals on the right side of the seat are anything to judge by. That would help to explain the presence of the tandem pusher C-frame.

Just my 0.02.

I have seen tree pushers mounted to separate trunnions, as Deas says, in heavy timber country. Often they would have a small winch or hydraulic ram at the back with a cable running over the top of canopy to lift the pusher higher for more leverage, work the tree over until the blade touched it, then back off and lower tree pusher for another go. Big timber takes a lot of work, even with D8H I occasionally had to dig the side of stump hole out so that could get butt of tree out of hole, or lay a log across at base of tree before pushing to lift it, had to back off quick or could get flipped by the butt. In heavy forest clearing we used long and heavy tree pushers, I had one pusher mounted separately to the blade trunnions.

By keeping weight of pusher off blade, hydraulics had more grunt to lift large logs when stacking.

Sounds logical Wombat and Deas, the only thing I have ever seen mounted on an extra rear trunnion is a tandem pusher frame, we don't have big tree pushers in the UK so can't comment on their mounting and operation.

Hi, Catsilver.
I'll let you off - - - - - - - - THIS time. LOL.

It was not uncommon to see a set of sheaves fitted to a hydraulic ripper such as on that D7E and another set on the roof of the timber canopy with a cable running through them and over the roof of the timber canopy to control a tree pusher such as was probably mounted on those trunnions - lower the ripper to raise the tree pusher, raise the ripper to lower the tree pusher.

One company in Western Australia back in the very late 1950's, working mainly down South in the big timber country, had the first 2 Cat D9Es to come into Western Australia. One of these D9Es was fitted with a tree pusher bar that was 32 feet long and could reach about 23 feet up a tree. Even that was nowhere enough to take out some of the bigger trees in that country.

These two D9Es were mostly used for chaining timber, pulling around 400 feet - or more depending on the timber being cleared - of 3" ship's anchor chain between them, often with a D7 or D8 fitted with a substantial tree pusher bar chasing the chain to help take out stubborn trees. At times in heavier going, they may only have been cutting 40 to 50 feet wide, even with all that power and traction. Still a LOTTTT cheaper than pushing down each individual tree.

Here is an OLD black-n-white of TWO D7s fitted with tree pushers chasing a chain with a hi-ball in the middle of the chain. It didn't take long for the hi-ball to be abandoned over in the West 'cos it made the chain ride higher and contributed to way more break-offs, leaving more stumps to be extracted later. It was unusual to see 2 dozers chasing the chain.



Chasing the chain would HAFTA be wunna the worst dozer jobs ever as you were always weaving your way through the already downed timber and were expected to be where the offending tree was in seconds if a tree stopped the chaining tractors. While that chain was stopped, so were the earnings as most of this work was done on a 'per acre' contract basis.

Just my 0.02.

Very interesting Deas, I have seen pictures and film of chains being used on land clearance, also the tree pusher 'mounted' above the blade but never realised it was operated independently of the blade. We just don't have the area to clear on this part of the planet, and any hardwoods, even on a clearance job, are always protected as much as possible to prevent damage and get as much useful timber out of them as they can at the sawmill. Track shovels with root rakes were mostly used from the early sixties onwards.

Hi All,thanks for everyone's help on the subject,i will get the dozer down to Westrac which is the West Australian Cat dealer and get them to look at it and give me a price to replace the worn out track parts needed.I will start saving as i know it won't be cheap but i do plan to keep the dozer.I'm not sure if you know a good Cat workshop over this way Wombat that works on the older machines, as i think most just work on newer dozers and not even sure if Westrac will be keen to look at it.
I have a few more closer shots of the undercarriage,i have been wondering what the rear trunnions were used for,they may have been used for the tree pusher bar,at some stage though i think the tree pusher bar was welded to to the blade push bars as you can see in the pics.
Just on another topic ,i have pics looking from the drivers seat,to the right is a round cylinder welded to the canopy post,just wondering what that was used for back in the day,it has a base to it,maybe to hold a small oilcan in,not sure but it is one heavy duty steel cylinder.

I like your pic and info of the adjustable tree bar on the D7's Deas,my dozer has actually had something attached to the front of the roof canopy which has been grinded off,maybe a pulley setup for an adjustable tree bar but not sure without a winch and rippers on the back but they could have been a later mod to the dozer.

I can see big money being spent there, oil around the left final drive and a bracket welded in to stop the left idler coming back, I would be inclined to find a local independent Cat mechanic for an opinion before talking to a dealer.