great shots Geo!
MY WORLD
- Thread starter fubar57
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- Thread starter
- #102
fubar57
General
Thank you gentlemen. Cat 825 compactor. Back and forth on the dump,compacting and leveling, about 800 times a day. With the steel wheels, it's a 4 kph torture machine.
Geo
Geo
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Matt308
Glock Perfection
michaelmaltby
Colonel
Keep the drive as high out of the 'muck' as posible and improve control on slopes, IIRC.
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- Thread starter
- #105
fubar57
General
Hey Matt, this is what I got off the interwebs. It explains a lot better than I can. Hope it helps.
"Unique among bulldozers is the high drive design shown in this photo. Caterpillar invented this design a number of years ago introducing it first on their largest machines and later on the smaller ones. As you can see the drive sprocket is elevated about the ground line. This has the disadvantage of proving one more place for the track chain to bend and presumably wear faster. This is critical because track wear is a very major operating expense on large dozers. Cat claims to have engineered around the problem with the development of sealed and lubricated (SALT) tracks in lieu of the traditional unlubricated steel on steel track chains of traditional times.
There are a multitude of advantages to the design, however. It provides for a physical separation of the drive sprocket from the suspension. This means that the drive sprocket (the elevated unit) does not need to also support the weight of the machine. This functional separation means that the drive mechanism can concentrate on managing turning forces and the suspension can be designed for weight support.
Most importantly, however, it gets rid of the dreaded 'final drive'. As long as their have been bulldozers there have been broken final drives. In the mid part of this century Caterpillar largely overwhelmed the domestic competition (Allis Chalmers, and International Harvester) due to the reputation of the others for broken final drives. The problem is that the drive sprocket needs to be relatively small in diameter to keep the ground speed down, but the dozer needs ground clearance. To accomplish this the drive train is mounted fairly high in the machine with the cross shaft exiting the sides of the dozer about where you see the "high drive" sprocket. In a traditional dozer there would be a small gear (a pinion) driving against a large gear (a bull gear) mounted below it which would provide the final gear reduction (hence final drive) and also the physical offset sufficient to provide the ground clearance. The problem with the little gear-big gear gear train is that the entire load of the vehicle is driven by a single gear tooth. the ability of a gear train to transmit power is a function of both speed and strength. The final drive by definition moves very slowly and must therefore be very strong. Every gear tooth must be strong enough to stall the engine or spin the track at a very low speed. Imagine the pressure developed on a gear when you take a diesel engine of several hundred horsepower, and run it through a series of speed reductions until it is down to just a few RPM and then concentrate that entire force on a single gear tooth.
So what is the Solution. The engineers solution is fairly simple. Just get rid of the final drive. The planetary final drive is the better idea. It is inherently much stronger, because it has 3 or 4 (or more) planet gears circling a sun gear providing the gear reduction. This means that there are always multiple gear teeth engaged at any one time making the drive mechanism inherently stronger than the 1 tooth solution. The problem is, of course, that the planetary drive reduction does not provide a physical offset. With the high drive design this is not a problem. The planetary final gear reduction is contained within the drive sprocket (behind the massive bolt circle) and all is well."
Geo
"Unique among bulldozers is the high drive design shown in this photo. Caterpillar invented this design a number of years ago introducing it first on their largest machines and later on the smaller ones. As you can see the drive sprocket is elevated about the ground line. This has the disadvantage of proving one more place for the track chain to bend and presumably wear faster. This is critical because track wear is a very major operating expense on large dozers. Cat claims to have engineered around the problem with the development of sealed and lubricated (SALT) tracks in lieu of the traditional unlubricated steel on steel track chains of traditional times.
There are a multitude of advantages to the design, however. It provides for a physical separation of the drive sprocket from the suspension. This means that the drive sprocket (the elevated unit) does not need to also support the weight of the machine. This functional separation means that the drive mechanism can concentrate on managing turning forces and the suspension can be designed for weight support.
Most importantly, however, it gets rid of the dreaded 'final drive'. As long as their have been bulldozers there have been broken final drives. In the mid part of this century Caterpillar largely overwhelmed the domestic competition (Allis Chalmers, and International Harvester) due to the reputation of the others for broken final drives. The problem is that the drive sprocket needs to be relatively small in diameter to keep the ground speed down, but the dozer needs ground clearance. To accomplish this the drive train is mounted fairly high in the machine with the cross shaft exiting the sides of the dozer about where you see the "high drive" sprocket. In a traditional dozer there would be a small gear (a pinion) driving against a large gear (a bull gear) mounted below it which would provide the final gear reduction (hence final drive) and also the physical offset sufficient to provide the ground clearance. The problem with the little gear-big gear gear train is that the entire load of the vehicle is driven by a single gear tooth. the ability of a gear train to transmit power is a function of both speed and strength. The final drive by definition moves very slowly and must therefore be very strong. Every gear tooth must be strong enough to stall the engine or spin the track at a very low speed. Imagine the pressure developed on a gear when you take a diesel engine of several hundred horsepower, and run it through a series of speed reductions until it is down to just a few RPM and then concentrate that entire force on a single gear tooth.
So what is the Solution. The engineers solution is fairly simple. Just get rid of the final drive. The planetary final drive is the better idea. It is inherently much stronger, because it has 3 or 4 (or more) planet gears circling a sun gear providing the gear reduction. This means that there are always multiple gear teeth engaged at any one time making the drive mechanism inherently stronger than the 1 tooth solution. The problem is, of course, that the planetary drive reduction does not provide a physical offset. With the high drive design this is not a problem. The planetary final gear reduction is contained within the drive sprocket (behind the massive bolt circle) and all is well."
Geo
Matt308
Glock Perfection
Crystal clear! 
I have always asked the question and never got a solid response. Thanks!
I have always asked the question and never got a solid response. Thanks!
Lucky13
Forum Mascot
- Thread starter
- #108
fubar57
General
This is what an 1100 man camp looks like.
A 994 loader parked beside a Rubber Tire Dozer(AKA-Duck)For reference, the R.T.D tire is about 7 feet tall.
The 994
Me getting the first load from the brand new Cat 7495 Electric Shovel. The first bucket load weighed about 100 tonnes.
EDIT: Stock photo added for size comparison
Geo
A 994 loader parked beside a Rubber Tire Dozer(AKA-Duck)For reference, the R.T.D tire is about 7 feet tall.
The 994
Me getting the first load from the brand new Cat 7495 Electric Shovel. The first bucket load weighed about 100 tonnes.
EDIT: Stock photo added for size comparison
Geo
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Aaron Brooks Wolters
Brigadier General
WOW!!! You have a great job George!
Cool shots Geo!
Matt308
Glock Perfection
If you asked me as a kid would I like that job, I would have yelled at the top of my lungs, "Hell YES!!!!!"
Crimea_River
Marshal
Good stuff Geo. Spent my share of time in camps too. Hope the food is good - usually is.
- Thread starter
- #113
fubar57
General
Food is awesome Andy. One more four day tour and then I start the 7on/7off shift. First is the forest fire that was West of the mine and a pit services guy setting up a light plant for night shift.
My new toy, a Cat 14M grader, the training machine. For reference, the tires are four feet tall. There are two bigger graders, 16M's. The left joy-stick controls; steering, shifting, forward/reverse, front wheel tilt, left blade lift cylinder up/down, and by twisting the joy-stick, the frame articulates left/right behind the cab. The right joy-stick controls; blade side-shift, lift cylinder side-shift, right blade lift cylinder up/down, blade rotation, and blade tilt.
Geo
My new toy, a Cat 14M grader, the training machine. For reference, the tires are four feet tall. There are two bigger graders, 16M's. The left joy-stick controls; steering, shifting, forward/reverse, front wheel tilt, left blade lift cylinder up/down, and by twisting the joy-stick, the frame articulates left/right behind the cab. The right joy-stick controls; blade side-shift, lift cylinder side-shift, right blade lift cylinder up/down, blade rotation, and blade tilt.
Geo
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Crimea_River
Marshal
Good stuff Geo.
Nice shots Geo!
evangilder
"Shooter"
Like giant Tonka trucks, only better. Neat stuff.
Neat stuff.
michaelmaltby
Colonel
"... the training machine"
MM
MM
Aaron Brooks Wolters
Brigadier General
I agree with Eric! 
T Bolt
Colonel
Great stuff George
Airframes
Benevolens Magister
Great pics Geo. That crane thing is not just bigger than my house, it's bigger than the whole bl**dy street !!
