Why wouldn't this work?

[Rock Doctor]

Slow day at work, and had another 6x6 world member bring up an idea that I've thought about in the past. (He brought up the idea of a Factory "Tracked Only" Argo, I'm just taking it a little further.
Picture this:
Argo on Tracks.
All drive chains removed, except for front Axle chain, or Tracks Tuners on all axles except the front.
Front tires replaced with some kind of wierd Positive Drive "Tire" that will mesh with the open spaces in the Tracks (Think Adair type Tracks). Maybe it would work better driven from the back, with a smaller "wierd positive drive tire" (Maybe something like the Aquatorque Tires, but with no curve to the lugs, just straight cut lugs across the tire face, spaced to fit the Track Grouser Spacing.

What would be the disadvantages of such a setup?
Would there be a positive advantage to such a setup?

Discuss?

RD

[hydromike]

I've always like this idea. I'm around a lot of track-mounted drill rigs for work and I'm always thinking that it would be pretty innovative to just commit a machine to tracks for year-round use. The first downfall that comes to mind RD is the losing what little suspension we have by eliminating the tires if we go that route. On an 8x8, if you could take the center two axles and use a modified-style tuner on them that essentially turns them into a bogie-like setup it might help out. Sort of what Cushman Tracksters have? It might end up looking something like Mattracks or Tatou tracks do, but just on the center axles. As you know on those setups, the cog is driven, but I don't see any reason that you couldn't just turn it into a 'tuner. The more I picture it in my head, the whole setup might end up looking a lot like a set of mattracks, but with one "track" connecting all of the 'tuners.

If you remove all of the chains except for the fronts, do you think that it would put too much stress on the front axles (since all of the torque is applied to just those two, and not distributed to the other axles) ?

As far as the positive advantage goes, it'd be awesome.

[JohnF]

Thought about this myself. You just described a snowcat.

The only thing I can imagine being complained about is the lack of suspension at the sprocket so I imagined a sleeve made of something like conveyor belt that has a fixed diameter that you inflate your tire inside of. It has cogs on it that fit the Adair grouser pitch. You put it on the front and remove all of the chains to the back.

Another: This one is based on Adair's double tired track system. The front "wheel" is a single unit that carries the two tires but the center used the tire guides in the center for cogs in a sprocket. Again, no chains to the back.

Positive - no chain windup, can't be, so no power loses due chain windup. A possible positive is that the tires become much less technical so probably a lot cheaper.
Possible negative is lack of suspension at the sprocket.

[Buzz]

With the right track and drive wheel I don't see why it wouldn't work. You might have more chance of breaking something as there would be less "give" or slipping if necessary. Less buoyancy, and you would lose some performance and/or ability to run on just tires if the need arises.

[Rock Doctor]

Gotta love how great minds think alike

OK, so lets leave all the tires on, so suspension will not be effected any more than any other track system. For the sake of discussion, lets say I have a 25" "Aquatorque Type" tire on the front of my machine, where the lugs just happen too match the Pitch of this mythical Track, and I have 3- 24" Frontier Tires for the other 3 axles........ I provide power to the front tire only, with the chains to the back 3 axles OFF.

The torque to the front axle should not be any greater than the force in the Trans Output Shafts, or the Idler Shaft though, right? If these components can take it, should't an axle take it? The Driving Tire on the front should spin on the rim before you twist off an axle...... Which brings up another possible issue...
There can be no "Chain Windeup Issues", if there are no chains, all back 3 sets of tires would be free to spin at any speed, so less worries about tire diameter.

John, would using a Tire as the Sprocket, as mentioned above, address your Sprocket suspension Issue?

Buzz,
Help me visualize, now that I've added more detail, do you still see "More chance of breaking, and less give" somewhere? Bouyancy should remain the same. Ability to run on just tires would definatly be effected, but what if you had your chains, and could put them on if the need arises? We would still have a 25" tire mached with 24" tires, but for a "Limp Home" run, it would be OK.


Am I getting to "Out There" yet, lol

RD

[plott hound]

buy yourself a bombardier "bombi".all the work is done for you.

[ARGOJIM]

Sounds as if you boys are heading towards a Snowcat. As far as the chain drive it seems all manufacturers either have equal pull on the jack shafts or center axle, I'm no engineer but seems equal opposing force issue at the point of transfer.

[JohnF]

Yeah, I guess I should have mentioned it but that's why I used the tire as the sprocket. I imagine the designers of the machine imagining that it would take torsional loads one axle at a time, imagine going over a log, and sizing all of the parts so a single axle could do it. I would also imagine we would all have stories and warnings of not loading only a single axle or face replacing it. But if it were a real issue we will only have to beef up one set of axles.

Also, I deal with the spinning tire on the wheel issue (forgot about that) and imagine this wheel sleeve system using a tire on a real beadlock wheel. I don't think I want it slip and like a tractor expect all slipping to happen between the track and ground. Note, with chains and tires and tracks (current system) I think the wheel being able to slip is important and necessary.

Oh, and a to the tires - the bogies can be any tire so soft ride would be where it is at. Also, size does not matter (really) so you could use anything reasonable (keep the track tight, etc).

EDIT: It just occurred to me that you might mean your tire as a sprocket (aquatorgue(ish)) vs my tire in a sleeve. Yes to that too. I would think a rubber only cog on a sprocket may have wear issues. The snowcat sprockets are rubber on steel. I was imagining my sleeve using UHMW or aluminum cogs to match the grouser depth. Worth an experiment - especially since all the parts exist.

[Rock Doctor]

buy yourself a bombardier "bombi".all the work is done for you.

LOL, I used to run one of those when I was 14yrs old, building Mining Roads. They are heavy and a PITA to work on. The one we had was a 4 speed with manual Trans....... Maybe it was 3 speed....... Anyway, good luck getting it into top gear without slowing down to the point of having to actually Backshift.
No, I want something smaller and lighter AND, something that could be made out of an older Conquest Parts Machine, lol.
The thought is rather similar to a Snowcat though, My buddy has about 5 of them, and a few Haglunds too, but I've never really had a chance to scope them out too much.

You lost me Jim, sorry. Equal pull on Jackshafts....
On a normal Argo drive system, you have the Idler Chain pulling up, Front Chain Pulling forwrd, and second axle chain pulling backwards on the Jack Shaft. But on the Trans Output shaft, there is only pull in one direction, same goes for the front axle......

RD

[JohnF]

Something else to to think about. Imagine that the pitch of this system is 2 feet - cogs on your tire and grousers - and your cogs on the tires or track are 2 inches. You will engage only one side of the cogs at a time and it could be a little unsettling if you crest a slope, stop, and the machine slides about 2 feet before it stops. A snowcat sprocket wedges the grousers and we might want to do the same.

... so suspension will not be effected any more than any other track system.

Just had to chuckle. Have you seen the suspension on the Abrams? Watch that guy going 70+ mph across fields and it is just too cool. Of course it has a little different sprung/unsprung dynamic going on... If we want to get into this realm even a little I think we are going to need to get Whipper involved.

[Rock Doctor]

John, I was thinking something more like 4" spacing between Track Grousers, and 2" wide Cogs on the tires (Apropriatly spaced so that the tire Cogs would mesh with the Grouser Pitch. So, if you crest a hill and stop, would you not only slide forward a couple inches at most, before the back side of the tire Cogs make contact with the "Next" Track Grouser?

As for the Track Suspension, lol, I was thinking "any other track system" on an Argo :-)
The Abrams are , but I can't pictue them making it into my cabin........... I could be wrong on that though, I've no experience with driving one through Muskeg

RD

[Buzz]

[QUOTE=Rock Doctor;139556]Gotta love how great minds think alike

OK, so lets leave all the tires on, so suspension will not be effected any more than any other track system. For the sake of discussion, lets say I have a 25" "Aquatorque Type" tire on the front of my machine, where the lugs just happen too match the Pitch of this mythical Track, and I have 3- 24" Frontier Tires for the other 3 axles........ I provide power to the front tire only, with the chains to the back 3 axles OFF.

The torque to the front axle should not be any greater than the force in the Trans Output Shafts, or the Idler Shaft though, right? If these components can take it, should't an axle take it? The Driving Tire on the front should spin on the rim before you twist off an axle...... Which brings up another possible issue...
There can be no "Chain Windeup Issues", if there are no chains, all back 3 sets of tires would be free to spin at any speed, so less worries about tire diameter.

John, would using a Tire as the Sprocket, as mentioned above, address your Sprocket suspension Issue?

Buzz,
Help me visualize, now that I've added more detail, do you still see "More chance of breaking, and less give" somewhere? Bouyancy should remain the same. Ability to run on just tires would definatly be effected, but what if you had your chains, and could put them on if the need arises? We would still have a 25" tire mached with 24" tires, but for a "Limp Home" run, it would be OK.


Am I getting to "Out There" yet, lol



yeah, you're definitely on to something. Keeping all your tires would be a huge advantage since you are amphibious unlike some track machines. Tires could scrub or skid to handle the wind-up okay. I've always thought it's cool that you're still in pretty good shape even if your tracks break or fail or something like that. Shoot, you're still an 8-wheeler which isn't bad at all. The only concern about using a sprocket that crossed my mind is if you "geared-down" the output of your drive sprocket so that your engine torque is multiplied and more than the axles and bearing cages (if you had them) and frame could handle. Usually, your engine bogs first, but with ultra-low gearing...who knows. And yeah, bringing your chains seems like a great idea too. Finding a tire that would engage like a sprocket would be great...if possible.
If not, I'm trying to picture the best set-up to maintain the bouyancy of the drive axle without getting in the way of a standard drive sprocket. I guess once you figured out the sprocket diameter that's needed, you could come up with a design plan...seems like floatation tires would need to be smaller than the sprocket. I have a feeling the sprocket would probably be smallish so that might be tough to accomplish...maybe just adding more floatation to the front of the machine (like a large boat fender that's removeable) would be the best. It would be cool if you could replace a bolt-on sprocket with a bolt-on wheel/tire if needed. In fact, if the body diameter (not teeth) of the sprocket was the same as the tires, you could interchange them without having to change the track length. And, the sprocket teeth would stick up higher than the tire tread. You might be able to sandwich a wheel/tire between 2 drive sprockets. Driving the "center" of the track with a single sprocket or both edges of the track with 2 sprockets I think makes the most sense (I think). I'm kind of "guessing" on all of this. I'm probably out there!

[JohnF]

... So, if you crest a hill and stop, would you not only slide forward a couple inches at most, before the back side of the tire Cogs make contact with the "Next" Track Grouser?

Yep, whatever the space is. I just used the 2 foot example to make it obvious. It would also slip when you changed fwd/rev. Ideally we would trap the grouser just like the snowcat does which could be a balance act between way too many grousers (cost, complexity) and/or sprocket cog flexibility/clearing issues.

The Abrams are , but I can't pictue them making it into my cabin...

It would be cool if you would go poke a driver in the chest and tell him he can't and watch him give it a go. The muskeg might stop him but I don't think you have any trees big enough to stop him.

...The only concern about using a sprocket that crossed my mind is if you "geared-down" the output of your drive sprocket so that your engine torque is multiplied and more than the axles and bearing cages (if you had them) and frame could handle...

Hehe... I guess we all got gears spinning on this. I imagined a track just like the Adair track that ride the outside diameter of the tire. The cogs are proud of this but don't extend beyond the grouser so the gear ratio should be pretty much what an track is now.

[ARGOJIM]

RD, every time I write a long answer it gets lost to the signoff demons. The point I was trying to make was all the force would be applied to the outer idler bearing, flange or frame as a potential failure point, the counter rotation of the chains reduces some of the force applied to the bearing and supports, by removing it, it multiplies the force applied at that point. A bearing at the inner frame rail may help this.

[Obsessed]

RD...I think you guys are all on to a great idea of a more efficient, lighter weight, and lower maintaince tracked only 8 wheeler.

I have played around with all of these ideas myself and my version of what you are describing would start out with a light weight and inexpensive 8x8 frontier....I would then slightly reconfigure the drive train to drive the rear axle off of the idler shaft (instead of the second axle back) which would run a longer chain and utilize the two rear chain adjusters.....this would then leave the two center axles disconnected, I would then chain them together and hack saw the last 5" off of each axle and then weld a short 3" arm with a new spindle and freewheeling hub welded to each axle with the front one pointing down and forward at a 45 degree angle and the rear one pointed down and back at a 45 degree angle (when one moved up the other would move down and the newer 8x8 frames with 27" axle spacing would allow this to work with the factory 24" tires)....this would give a simple and effective walking beam type motion on the two center wheels and increase ground clearance an inch and a half... It would also use all origional drive components, less 4 sprockets and only sacrifice the modification of the 4 center axles...no permant damage to the machine. I have ideas that would take this design even farther for improved performance. In fact, I have taken this concept so far over the past two years that it is now turned into a custom built machine (actually a couple different models) that are currently under build as prototypes for testing purposes with the intention to someday be in full production..

RD, I'm not able to easily post pics from my phone, but if you are serious about building a custom tracked 8 wheeler and would like to see what I'm building I would be happy to email you some pictures and start to get some feedback and suggestions from a few more of the forum members.

I'm enjoying all your creative ideas.

Tim