ACCO bulldozer moves again

[SRB]

RE: top carrier rollers on Cat Hi-Drives, the D9T cant be sold into the EU market with carrier rollers fitted as it no longer meets the required sound level - the bulk of sound on a dozer comes from the undercarriage - a series of impacts, roller to link, idler to link, sprocket to tooth etc, there have been a number of ways around this, there is / was a D10T at Miller Argent with a sound package on it, this included rubber segments on the idlers, sound suppressed rollers and final drive casing.
There was also a D9T destined to go into HJ Banks with an enclosed final drive area, however it never went out to due fears of material becoming trapped in the area and accelerating wear...
On another note, ive always pulled the top rollers off, as have had more grief with them than enough. Mainly due to material on site i have to add, its easier to not dig the tracks out as often and let the rails "slide on the muck" rather than have a stuck top roller that flats off... however this im more down to attitudes to daily maintenance (digging tracks out) than anything else........

Just my £0.02 worth......

All the best

SB

[Gavin84w]

TC, i worked in a mine where we got 750 hrs out of the grousers on a D11R, god damn that stupid high drive......... The stories of Cats wearing out undercarriage are absolute myths that never have an apples for apples comparison done, the talk of the tracks hitting the rear frame just above the canon seal is such a joke that it is a design issue, it,s bollocks, if the adjustment is right it will not hit there full stop. I get so pi$$ed when i see wear there it just comes down to laziness.

Take a D9G and a D9T, you can not tell me the 9T today will not outproduce the old 9G, it runs so much faster of course there might be more wear but it got more done.

I have customers with D11R ripping partings in a coal mine that achieve 10000hrs to destruction, they have D10T that get the same and also an XQ coal dozer that we are doing the chains on now at 9500, idlers/rollers all still 60% remaining.

I might be coming across a bit harsh but i know elevated sprocket tractors like the back of my hand and sure they have some issues but i know for the most part the rumour mill feeds a lot of myth about them.

[brian]

As far as smaller dozers go, I know that, in reverse, a 6 with a carrier roller doesn't throw as much mud at the door glass as a 6 without. I can't say I've noticed the top roller makes the tracks any noisier on the smaller dozers, if anything it's quieter as there isn't the whipping up and down.

[tctractors]

Gavin, the tractor I spoke of Ref Chepstow Plant was a D6H early build, this was put out on self drive hire and managed only 1'200 hours on general hire as a blade only tractor before the under-cart was dogged out, the amount of wear to the top Cannon section I have seen on the high drives without the little wheel fitted is considerable, plus the fact that Finning had repair wear pads on stock?? gavin in the U.K the undercart is usually run out past its limit and then some, 1 bodge was to poke an 1" thick plate in front of the adjuster making the stops bend inside the Cannon just to take out that bit of slack, as for the maintanance issue of track adjustment to stop the track dragging off the top of the frame Gavin, in the U.K. sometimes its like being in the 3rd World, I once went out to fix a Dump truck also on the site was 1 of the Companys new D6R series 2 tractors after fixing the Dumper I checked the other kit on site including this new Dozer, I first checked the F/Drives the oil was a bit of a shock to me as it sparkled like a Jewlers Bench, then I checked the service display showing the Linear distance travelled and Hours worked, it had not been serviced from new delivery with a clock showing over 1'600hrs ??? thats the way I love em ready to Calve down, the wear rates on early High Drive undercarts is a well known issue with all sorts of mods etc made to increase its durability like RTB etc, but the important thing is the twin drive rims on the ACCO?? and no I dont think you are being Harsh Gavin it does not bother me how long or how much noise a tractor undercart manages as I dont pay for it, the vintage CAT's that I have are on good boots.

blowing it on tctractors

[tctractors]

Gavin,on re reading your post I hope you are not putting my script on the early running gear in any doubt, as that is what the little chariot managed and that is why Chepstow Plant Hire went over to the D65 Komatsu as a self drive hire unit at that time, this is "fact" not dream steam, I will admit that the High Drive tractor is a very fast chunk of Iron and would easy see off any other tractor in the work stakes, but dont think that Iron in the U.K. gets the care and fettling that machinery does in other parts of the world, as you would be in for a shock, also please dont think that the drivers are keen to do any running service work to their mounts, this would not be the common thing the rare thing is to find equipment in a good state of daily care, last week I drove out to a site to sort a Volvo excavator that was acting up on the engine speed control, I found the driver had flicked a switch in the override compartment where drivers should not go? anyhow I sort it and check its working fine, only to get a call that the machine is acting up again doing just the same as before??, so I go back out and find the driver has moved the master control switch in the secret little hole back to manual control, I asked him W.T.F. he was doing??? to be told that he did not know what it did??? this did nothing to improve my mental state if the excavator was mine he would be poked down a deep hole and back filled fast as this is not helping mankind, the tough bit for me is to send the Company a bill for my time flicking a switch twice?? my head hurts.


S.R.B. nice bit of script stuart on top carrier rollers, I still like to see em on the tractors though, but I am from a dig out the frames twice a day era, but it was a great bit of script, any comments on the double rim drive???

[bigkit]

Deas, the older style (Oval ) track design put about 6-7 in average track bushing copping a load from the rim, the high drive set up gives 3-4 track bushings a right hiding with very fast wear rates, this is well known World wide with plenty of owners avoiding the CAT system, the ACCO tractor is driving through about 7 track bushings with planitary hubs so the loadings are possibly a lot more comfortable than on the Oval (flat track) system and would be a big improvement on the single drive hub used in the High Drive style tractors that CAT knock out, the drive system used in the ACCO would put only half the loading onto each bushing in the drive point, on the top roller thing with CAT, they used to sell wear plates to weld onto the track frame to lessen the damage caused by the track smacking down onto the top of the frame, the track would be flaying about like a Bull Whip when the tractor had the "Boot" stuffed into it, the damage to the front idler mounts and track link War wounds would make your eyes water, just why it took CAT so long to poke a simple top roller in beggers the grey matter??? they were an option at 1 point then a standard fitment, I can recall a Chepstow Plant Dozer burning out a set of tracks in 1'200 clock hours, the CAT's were swapped out for Komatsu as they could not make any Coins with the early High Drives.

Maybe my thoery wasn't that far off?

[brian]

Personally I think a big factor with the hi-drives is how quickly you can get the power on after a direction change, which can cause a lot of snatching. I've seen them operated like this routinely and they are easy to abuse. The Cat hystats are a bit gentler easing the power onto the tracks after a change of direction. Steering wise, the diff-steer Cats don't seem to snatch at the tracks the way the clutch-and-brake steers do.

I'm with you on the digging out tracks, Tony. It's laziness not to, and you can miss a lot of other stuff around the equaliser bar and trunnions. Next thing there's mud packed around the pins, hydraulic lines, everywhere yo don't want it.

[Deas Plant]

Hi, TCTractors.
Yes, I know that there are more pins nd bushes around an oval track sprocket than around a hi-drive sprocket. How-wevver, I have been told by several people whom I would expect to have some idea 'cos that is their game that that is not the main issue. I'm no track wear expert but these people have all told me that it is only the first 3 or 4 pins and bushes that have any REAL load on them as they are travelling around the sprocket, regardless of how many pins and bushings there may be around the sprocket. By the time they get further around than that, the load is gradually reduced until, by the time the pins and bushes get to the other side of the sprocket, there is not much if any more load than on the chain that it travelling across the top of the track frame, at least when travelling forward.

What posed the biggest problems with the Cat Hi-sprocket drive when it was first introduced were two things:

A. The track was travelling around three separate radii as opposed to only two on the oval track and they were all smaller diameters than the oval track which meant that there was WAY more internal pin-to-bush movement than on the oval tracks.

B. That never-ending and violent whipping of the track chain between the sprocket and front idler which caused even more internal pin-bush wear.

I don't really see it as fair to blame the Cat R+D people for operator laziness that contributes to excessive wear. And if hire companies want to rent out machines on a dry hire basis and then find that said machines are being abused, maybe they ought to start charging for said abuse like they often charge a cleaning fee if the plant is returned dirty.

Just my 0.02. Let the debate rage - - - - - - peacefully and informatively, I hope.

[tctractors]

Deas, sorry but I cannot let you get away to easy now on the ACCO, in your own print you point out the 3-4 tooth contact, well the ACCO pulls through 3 pins on 1 sprocket and 4 pins on the other rim, I am very confident that both rims would be pulling with the same effort due to the planitary style drive, so that would be as good as thing would be expected by your "People" that know??? how do you read it???, on the top carrier roller thing, on the standard oval drive style tractors, it was the common thing to fit an 1"1/2 packing plate under D8-9 top roller mounts, this stopped a lot of muck build up and placed positive load onto them keeping them turning without flats developing, the High Drives with the top rollers in my mind are a better prospect, the fact that they lesson the noise level by omitting them does nothing for my ears, the biggest leap forward ever with track noise was the SALT track group,the top rollers where fitted to the H-D tractors at 1 point so they must have been some use, if I was pushing out coins on H-D D9's I would fit top rollers on em and pass around the ear plugs, Gavin said one of his pet hates is to see top frame wear caused by slack undercart due to poor standards of service, well the U.K. might make him ill as some of the sights I see make me "Air Lock" but I let go by me.

[Deas Plant]

Hi, TCTractors.
What these people have told me is that each pin and bush takes less load as it gets further away from its first contact with the sprocket tooth and more pins and bushes come on to the sprocket. By the time it gets to the top (travelling forward) all the load that it has is the weight of the track across the top. This makes perfect sense to me, whether others can see it or not.

As I understand it, the same thing applies to both oval track and hi-sprocket machines. It's just that the hi-sprocket machines don't have as many links engaged with the sprocket at any one time but I would be VERY surprised if the last pin and bush on a hi-drive sprocket was copping as much strain as the one just coming on to the sprocket.

Way back in 1910, Ol' Ben Holt built a tracked ditcher with the drive sprocket where the top carrier roller would be on a Cat D4. It would have had ALL of TWO pins and bushes enaged with the sprocket at any one time, maybe only one, 'cos the track didn't wrap around it any more that it would across a D4 carrier roller. It apparently still drove and steered quite well with that little sprocket-to-tooth contact. Now I grant you that this machine was basically only pulling its own weight, not a drawbar or blade load but it was the first hi-sprocket drive that I know of and it got the job done with about one pin and bush at a time in contact with the sprocket. Given CORRECT chain tension, why do we need more? (Yeah, I know. "Given correct chain tension")

Re the track chains rubbing/bashing on the track adjuster cannon behind the front idler on the hi-sprocket machines, to me this is symptomatic of the 'care less about job and machine and want more for it' attitude of the current generation of operators. I would really like to see some of them fronted with a gate change D8 with a LeTourneau DD CCU and a LeTourneau cable scraper on a job with mud and rocks and told that if they don't operate it and operate it well, they don't eat.

Just my 0.02.