Is there anything wrong with using tank track undercarriage for a bulldozer? how about if we shaped the drive and idlers like the dozer but left the 6 or 7 idlers in the middle from a tank but on a dozer, why dont they, just comes down to cost? performance wise could it be done?
The track system used by most countries is designed for high peed travel and is a live track system. There is at least 2 pins that go all the way through the track block in rubber bushings. The pins are held together by end connectors that also act as the grip/torque area for driving the track. Then another device clamps over the pins in the center of the track with 2 fingers that run in between the support rollers and road wheels called a center guide. A live track system is designed for adequate traction and mobility. A dozer track system is designed for raw tractive power. And tank track isn't cheap. While it can be rebuilt that cost was 28,000 per tank in 96 when I retired. I don't know what the cost was for new track. Now this is for the M1A1 tank. Also they have rubber track pads, 2 per block and they are a high wear item. Tank track is good for about 2500 miles. That's way less than 1500 hours. and at 40 MPH under 800. It could be done but it wouldn't be economical I don't think. If you think about it for a second, Cat, JD and other manufacturers have access to the tank track design under the freedom of information act. Nothing classified about the track. If it would be more cost effective they would be using it already. Rick
Steel undercarriage in the dozer or excavator style is basically a commodity now and is at it's cheapest in history with Asian production.
Tanks have some form of suspension to take some of the impact from being transmitted to the crew, the armament, and the electronics/optics. Suspension doesn't help when you're trying to cut grade.
Good question Indy100 ? Russian Dozer using tank style tracks . http://chtz-uraltrac.com/catalog/items/11.php FMC log skidder working . https://www.youtube.com/watch?v=ZsW7pRq38MQ It's chassis is based off the M113 personnel carrier . https://en.wikipedia.org/wiki/M113_armored_personnel_carrier
Well a medium sized dozer say the Komatsu d85 costs about 100 grand to replace the undercarriage. I'm building a D11 RC version and I'm looking for max tractive force, after calling both CAT and Komatsu, mechanics etc no one can explain why it's not done other than tank tracks would cost more but couldn't say anything regarding traction. The end of the day you need enough weight to power ratio. I'm looking strictly for performance so if anyone has any ideas let me know...cocks on tracks, skinnier width pads, more weight, more power. After some research there is no differenc ein tractive force using a high drive version versus low drive, has more to do with the configuration of the machine itself.
In the larger dozers, they have bottom bogey articulation along with track oscillation regarding the front idlers, I don't see why it's not possible to duplicate incorporating tank tracks, only thing is having giant idlers essentially giving option of faster speeds and a different look. (not as fast as conventional tanks due to not elevating both ends)
Yes huntoon, I have to agree, especially recently. Have you seen the newer komatsu line of dozers in last five years+ and how cheap they have gotten, the rep even admitted yes we are finding ways to cut costs. I'm not saying conventional undercarriages are cheap, I'm saying the overall build quality and performance could be improved. "Cheaping out" has been commited in other areas of the build moreso komatsu. Komatsu track pads are only rated for 4000 hours, CAT is 6000, We got over 9100 hours on our D8.
Horses for courses. The answer simply boils down to the track systems being designed for a specific purpose, with cost and longevity being prime factors. Tanks are meant to move the machine over rough terrain, at speed, and the tracks are designed to not only do that but have some resistance to armament and explosions, and be readily repairable in the field by the tank crew if needed. Dozers evolved from a different family tree with markedly different design requirements. Approaching the question from the other direction, why would you use a tank track system on a dozer?
Vickers converted Sherman tanks into tractors after the war. They reversed them so the drive sprocket was in the rear. This photo was from 1948. I was never sure why tanks put the final drives in the front unless it was to keep the engine in the rear and have more room for the driver in front.
As our resident military hardware expert pointed out in post # 2 above, tank track don't last 5 minutes. I shudder to think what undercarriage cost/hr would be on a D10 if tank style tracks were used....... Source..? I can't believe that is true when a pair of brand-new tracks, a complete set of 16 new rollers, 4 new idlers, and a set of sprocket segments for a D10T (about the same in size to a Kom D355) comes in at under $60k at today's Cat dealer prices.
Nice... as an ag or pull tractor ala Challenger, they would be sweet.
I'm talking Canadian pricing here, your military hardware expert says tank tracks wouldn't last 5 minutes on a dozer? I find that hard to believe. All I'm wanting to do is replace the rollers and bogies with 5 or 6 idlers, most everything else can be the same.
Actually most Main Battle Tanks like the Leopard I and II, M-1 Abrams, Leclerc, Challenger, Chieftain, T-55 to T-90 have the drive sprocket in the rear close to the engine. Other armoured vehicles like the M-113, Bradley IFV, CV-90, Marder etc. have the sprocket in the front. Having the drive sprocket in the front or back isn't a huge problem for armoured vehicles as the sprocket is off the ground and farther away from any impacts, they also usually incorporate torsion bar suspension that also helps absorb impacts associated with cross country travel at speed.
I think you were considering a higher speed undercarriage (not that I'd recommend it) on a smaller dozer like a Cat D3 or JD 450 see about putting a rubber track on it like what's being used on CTL's. I recall seeing some of the little grey market Mitsubishi's and Komatsu's being equipped with rubber tracks. Tank tracks are not really made for dozing work they are just made for cross country travel and like posted before ease of maintenance....but it's your money do what you want. And maybe have a look at the FMC tracked skidder thread to get an idea on how long the tracks last under heavy load they were built on the FMC-M113 Armoured Personnel Carrier chassis and I believe are still being built but mostly for the Wildland Firefighting Industry.
I knew a machine shop that made hundreds of thousands of dollars over several years boring and rebushing/repinning FMC skidder track plates. They are as someone mentioned based on a WW2 era design and haven't changed much.
To the OP. What size of machine are you thinking about..? In one post you mention a D11 RC, then a Komatsu D85, these are very different animals.
YEs thanks for that, while I'm not looking at going super fast I wanted to have use of third gear using some sort of hybrid track design to allow for a bit faster travel speed, 5 or 6 idlers smmeed to make the most sensewhich could articulate/pivit ie d8 or 11 for more traction. My objective is to make an industrial rc dozer more powerful than a d11 for the same size but if it can travel along faster when not pushing would be a plus, it's not a big deal but since I'm designing it, why not try something with a different angle on things. I'm not trying to reinvent the wheel just thinking outside the box a little.
Nige, what size machine? I'm looking at doing a 1:10th scale d11 partly because americans have this unsatiable appetite for high drive tracks not to mention I think they look better also. This dozer will weigh in around 325 lbs its 21" blade about 46-48 inch long, 3" wide tracks. I'm not doing exactly to scale, going with a super long track (more room for components, easier to level material,almost look like a mini train with a blade,wanted smaller blade width to increase cutting hard ground,technically will have 2-4 extra bottom rollers if I decided to go traditional track system)
In that case the issue as I see it is width. A traditional tractor has a relatively narrow chassis with a track frame on each side that oscillates around the pivot shaft axis to maintain the track frames pretty much aligned with the undulations of the terrain. The range of movement of the track frames with respect to one another and the chassis is controlled by the equalizer bar. A tank doesn't have this feature, each individual axle or bogie is pivoted straight from the chassis and its movement is controlled by a spring and/or shock absorber. The difficulty as I see it is how to redesign the track frames (or do away with them altogether) in order to accomodate a fairly long travel suspension system that would be required to fulfil your design brief.
The flip side of that is that anyone can use caterpillar's high drive sprockett design but no one has. I do think it's a good idea for elevated design ie easier for maintenance and keeps it out of the mud but I'm leaning towards some sort of hybrid track system to enable faster speed travel, nothing as fast as a tank but so that companies would not disable third gear due to excess wear.
The reason 3rd gear is disabled is not wear per se but to prevent the tractors from being travelled willy-nilly around the job site as mining operators are wont to do. An old boss of mine always used to say about TTT that "when they're walking they're not working" hence the reason that for anything over 1000m of travel the dozer was put on a lowboy and moved that way. The increase in cubic metres of material moved per hour was nothing short of staggering. If you want a dozer that can be mobile enough to work in multiple locations buy an RTD as opposed to a TTT......
All this for a rc dozer? Build how ever you want it's a toy
Dozer tracks are designed to handle double the tractors weight. So if a machine weighs 30 tons, the tracks can handle a 60 ton load. You can check this by looking up the pressure on the recoil spring for each track. All that I have had the pleasure of replacing required the weight of the machine for preload before the nut was screwed down on the retaining bolt. Tank tracks are designed to carry the machines weight and little more. That set up is about what they do with excavators. A recoil spring on an excavator is only pressed to half the weight of the machine. Tank track is a variation of the flat pad design. Pads are attached to each other, sort of like the old cranes. Dozer track uses a chain link design and the pads are bolted to each link of the chain. I have had the misfortune of working on FMC skidders. There were two type of tracks for them. The tank tracks had open ends and fell apart very quickly when trying to handle the trees we saw in the late sixties and early seventies. The logging tracks were completely closed on the sides. They lasted longer but cost a whole lot more. I remember seeing a bill for one track back then running in at $22,000. There were tricks to working on them and actually they are the lesser of problems. Torsion bars could be replaced weekly and usually exploded inside those tubes under the machine. It could be like sticking your hand into a bucket with 10,000 dull razor blades.
John C. , thanks for the insights about tracks and track chains. The FMC skidders didn't seem effective. They only looked like something 'piggybacked' onto a paid-for existing design; like the yarders on tank chassis.
The FMC skidders would drag in trees real fast. The grapple skidders were probably the fastest I've ever been around. Problem was the cost per unit moved got real expensive when repairs had to be done.
Vickers brought out the VR 180 and the VR 140 with tank like tracks, good for towing scoops or pans as they had high speed and a smooth ride but in rocky conditions would be prone to having problems with rocks and timber etc jamming in the tracks. They didn't last long on the market so must have had some short comings.
WEll because this is an industrial robot, apparently it's not a toy and is quite dangerous if it gets out of control. I'm not even allowed to use an ardiuno in it for the brains. If I was ever to sell it I could face liability issues so I'm looking for failsafes and to keep possiblitiy of resale open to perhaps to do another one or say an excavator. There are many out there but not properly thought out. There's a commercial d65 komatsu out there in europe for around 15000 euro but its much smaller and I don't think mine would cost anywhere near there making it perhaps more appealing. There are the purists out there who only want original d11 look but perhaps I can modify mine a bit so as not to take away too much but add some class to it as well and professionalize it, ie monster truck look gravedigger paint job for example. A nice vibrant green paint job for example could be perhaps highly visible as well. Put some rolling curves on her frame like the old 1956 ford f100s, try to get away from the blocky look, among many other ideas.
Can I ask what this is for ? I'm just curious.
Iwas not aware there was a radio control thread section:beatsme