Mini Hägglund

[WILLD420]

I think you are on the right track and with some of the advice on here, you will be served well.

Have you considered trying to source U.S. parts and ship them over? You are re-inventing the wheel so to speak, which is always a sure way to increase the amount of heartache and work you will endure.

I understand your size limitations, but I believe you would be better served with lightweight snowmobile tracks, which can be bought in smaller sizes for a lot less than it's going to cost you to make your tracks, and they will hold up much better for what you are looking to do.

They make youth models of snowmobiles, which have much smaller tracks on them. They are also a lot cheaper. Shipping would be the most expensive part of the deal. Perhaps you could source some from an adjacent area?

[Steinbruchsoldat]

Originally Posted by WILLD420

Have you considered trying to source U.S. parts and ship them over?

Hi,
i don`t know if you ever shipped parts from the U.S. to europe, but i did a lot. I can tell you that it`s expensive as hell, especially for big parts like snowmobile tracks. And if i would go with snowmobile tracks i`d also have to use snowmobile idler wheels and sprockets...

Originally Posted by WILLD420

You are re-inventing the wheel so to speak, which is always a sure way to increase the amount of heartache and work you will endure.

As already stated, there are a lot of homemade tracked vehicles using tires as tracks. So it`s not reinventing the wheel, i`m taking ideas from guys that built some successfully and trying to improve them...

Originally Posted by WILLD420

I understand your size limitations, but I believe you would be better served with lightweight snowmobile tracks, which can be bought in smaller sizes for a lot less than it's going to cost you to make your tracks, and they will hold up much better for what you are looking to do.

Well, i`m not sure why you think it`d cost a lot to make my tracks, because it doesn`t cost me anything. I got the tires for free, and have the bolts already laying around...
I`m just trying to built it like i think it`ll work. If it doesn`t work, well then it`s a lot of wasted time, but not more. Then i`ll start looking for alternatives, but will most likely built some real snowcat tracks, out of conveyor belts and grousers. But since i have a lot of free time at the moment i`ll just try my ideas first...

Don`t take this as offense, my english isn`t that good, so it could sound like that. I`m always happy to hear some other opinions and thoughts, but please don`t talk about snowmobile parts anymore, because this just won`t happen... Thanks...

I think i came up with a pretty good solution for connecting the tracks:



The orange fabric has a breaking strength of about 2.5 tons, so i think it should hold up fine...

[BotterbrodtGE]

Originally Posted by Steinbruchsoldat

I think i came up with a pretty good solution for connecting the tracks:



The orange fabric has a breaking strength of about 2.5 tons, so i think it should hold up fine...

Seems like a good idea,
Maybe use this to line the bolts around the whole track to keep the washers from pulling out over time, might help make the track more solid to hold the bolts.

Just a hunch

[Elwenil]

Webbing is very strong but it wears poorly and will weaken as it frays.

[Steinbruchsoldat]

Originally Posted by BotterbrodtGE

Seems like a good idea,
Maybe use this to line the bolts around the whole track to keep the washers from pulling out over time, might help make the track more solid to hold the bolts.

Just a hunch

Sounds like a plan if the tracks aren`t holding up...

Originally Posted by Elwenil

Webbing is very strong but it wears poorly and will weaken as it frays.

I burnt the holes in instead of drilling them, so it shouldn`t fray out much. Time will tell...



What i could use some help is the steering. I was planning on using the steering rack from the donor car, but because the steering wheel is on front and the steering rack on the rear, the steering column is going to be complicated. I already came up with an solution for the steering rack, but it´d be complicated with a lot of u-joints and stuff...
So the best would be finding an orbitrol and doing full hydro, but that`s the same as for snowmobile tracks, there are just ridiculous expensive. Anyone has an idea for that?

This is what i was thinking, but please keep in mind that i have no ideas how that kind of stuff really works:
I know how you guys do hydro-assist with tapping the steering box and adding a hydraulic ram. Would it be possible to do a setup like this without connecting the steering box to the actual steering? Like mounting the tapped steering box like an oribtrol and using the hydraulic ram for steering? But from what i understood this won`t work, because the steering box needs to be connected to the actual steering to work as a valve...

Would be nice to hear some advice on this, because i know you guys know more than me about this kind of stuff.. :

[87manche]

is having a steering wheel a requirement?

A simple spool valve could run your two cylinders:

http://www.northerntool.com/shop/too...alves-_-201612

and should be somehting you can find off just about any piece of heavy equipment.

[Elwenil]

I was referring to the wear from the contact with the metal drive sprockets. It will work, but may require frequent repair.

[Steinbruchsoldat]

Originally Posted by 87manche

is having a steering wheel a requirement?

A simple spool valve could run your two cylinders:

http://www.northerntool.com/shop/too...alves-_-201612

and should be somehting you can find off just about any piece of heavy equipment.

I thought about that too, but wouldn't it be hard to return to the neutral position?
Oh, and i just need one cylinder (at least i think so ;-D)

Originally Posted by Elwenil

I was referring to the wear from the contact with the metal drive sprockets. It will work, but may require frequent repair.

I thought i put some rubber on the sprocket, so that shouldn't be a problem...

[87manche]

Originally Posted by Steinbruchsoldat

I thought about that too, but wouldn't it be hard to return to the neutral position?
Oh, and i just need one cylinder (at least i think so ;-D)



I thought i put some rubber on the sprocket, so that shouldn't be a problem...

a little, but I kind of figured this thing isn't going to be running down the road at 60 MPH either, lots of rollers and road grading stuff uses a hydraulic tiller and does just fine at 10 MPH.
It just takes a little bit to get used to driving one. slight "bumps" of the control lever to get your straightened out.

[RoosterBooster]

not to sound negative (heck you can blow your free time on whatever you want )
... but what i dont understand is why you want to go with this (imho overly complex) design

if i understand you right you want the Rig to fit into the back of your minivan
(that has most likely not a very large cargo capacity) and are not going to use the rig in wide open tundra ...
...so for me the length of 4 tracks and the large turning radius of a "articulating frame" steering just does not really make sense.

what is your reason to not just stick to a (imho shorter, lighter and simpler) 2 track design and the almost "zero radius" steering of open diff/2 lever cutting brakes ?

[Steinbruchsoldat]

Originally Posted by 87manche

a little, but I kind of figured this thing isn't going to be running down the road at 60 MPH either, lots of rollers and road grading stuff uses a hydraulic tiller and does just fine at 10 MPH.
It just takes a little bit to get used to driving one. slight "bumps" of the control lever to get your straightened out.

You're right, i think that's probably the way to go. But i just had an idea to do a self centering setup. But this is way down the road...

Originally Posted by RoosterBooster

not to sound negative (heck you can blow your free time on whatever you want )
... but what i dont understand is why you want to go with this (imho overly complex) design

if i understand you right you want the Rig to fit into the back of your minivan
(that has most likely not a very large cargo capacity) and are not going to use the rig in wide open tundra ...
...so for me the length of 4 tracks and the large turning radius of a "articulating frame" steering just does not really make sense.

what is your reason to not just stick to a (imho shorter, lighter and simpler) 2 track design and the almost "zero radius" steering of open diff/2 lever cutting brakes ?

Ok, I'll try to explain: First of all, the van has a one ton load capacity, so i think i'd do something wrong if it weights more than that...

Why going with an articulated design? A two tracked vehicle this long and narrow wouldn't make much sense because it'd flip easy. I also don't want to make it any smaller, because i want it to be able to carry some stuff.
I think the bigger turning radius is even an advantage over the zero turning radius because the side load on the tracks is a lot less... Also the articulated design is a lot more capable if its the same size vehicle...

And the most important reason: I just think its freaking cool, and i liked that design for years...

[Elwenil]

Can't help but be reminded of this:



http://www.techeblog.com/index.php/t...iced-at-11-999

If it's going to fit in the back of a minivan, at least what we call a minivan over here, it's not going to be much bigger than a lawnmower.

[WILLD420]

No offense taken. Not trying to talk you out of something, but as a person who has wasted a lot of his life trying to make something work cheap, then having to go back a few years later and do it right the second time, I have a bit of experience in doing things poorly.

Something I have learned the hard way from my own and others experiences, is that there is no amount of money in the world that is worth watching someone you love get hurt or be in danger of freezing because you wanted to save some money. I also have a strong aversion to walking because my rig broke, so you could call me lazy. I've also had to fix things in the snow and mud, which quite frankly, sucks.

You are right that the tire tracks have been done before. What is different is your method of driving them. Internal grousers are a proven design for a reason. They work. Your method lacks the strength that you will need to prevent destruction of the track if the drive wheel should slip, the track lose tension or slip from the rollers or drive sprocket. As you have stated, the pictures above are ideas in the making and plans that are being discarded as they do not work out. This is good.

I think you can use the bolts you already have installed, but make connectors between them, with raised cogs to drive on your sprocket. This would spread the load between four bolts, rather than just two, and not add too much complexity or weight if done right. If these connectors were designed that the four bolts were tied together, across the track, then you would gain the stiffness you need in the track for turning, as well as load distribution between 4 bolts rather than only 2 at a time.

If you plan on using rubber tires for your carriage wheels, then you can design them to run inside the connectors, which would be basically an internal grouser, and they would keep the track aligned.

Steering: Is this to be articulated in the center with the steering as that of an articulating tractor? If so, then hydraulic cylinders are the only way to get the strength you need.

As with everything else, you need to do as the professional engineers do, over build it, because you never know what will happen or where you may wind up, and you don't want to build it with the idea that you will always be on a packed trail, with perfect conditions. With cylinders, you will be well served with a joystick control on a valve, unless you want to build an orbital steering setup. Orbitals bring on all kinds of plumbing and mounting issues, whereas a simple hydraulic valve can be very easy to configure.

Have you considered using turning brakes on the front portion, and just allowing the rear to follow, as a trailer would do? If you did turning brakes on both the tow vehicle and the trailing portion, you could easily make them work on opposite tracks, thereby forcing your two portions to pivot faster and work with each other, rather than having only one end of the vehicle do all the turning. With turning brakes you cannot weld the differentials solid, but you may gain maneuverability and control that you may not have with just the rams to steer with.

We have not discussed your options with regard to salvage yards, or equipment. If you have access to a rural area with agriculture, then you may be able to source a lot of things that will help you build this easier. Otherwise, you are going to have to figure out how to make automotive stuff work. Weight is going to be an issue for you with your desired method of transportation. Have you determined a gross unladen weight target? Have you weighed the engine and drive components you are going to use?

I looked at your rotor with the drive cogs on it. It's a good example, but the rotor itself will not work as you have done the cogs. Rotors are traditionally cast iron, and unless you are better than average at welding cast iron to steel, the joints will be brittle and subject to fracture under shock loading. The only way I can see that working, is if you drilled a hole through the rotor, tight enough that the pipe would barely fit through, then add gussets from the pipe to the rotor center. This would require heating the rotor, piping and gussets to at least 500 degrees in an oven, then welding and reheating to keep the temp of the whole thing above 500 degrees. Then either bury it in hot sand, or wrap it in blankets so it cools slowly. The key is to allow them to cool at a speed that prevents the two metals, which will contract at differing rates, to cool slow enough they don't stress the joint and crack.

[Elwenil]

I'm thinking that adding angle iron (or aluminum if you prefer) to the bolts as mentioned above and for a drive wheel, a normal wheel of the correct width with round stock or bars of some sort welded across the width of the wheel. You could even go a step farther and use a rim wide enough that the entire track would fit in between the rims sides to help keep it in line and then put the drive bars deeper in the rim. Not sure if I explained that so that it makes sense, but I'm thinking of drive sprockets along the lines of what is used on the Ripsaw:



The drive "teeth" down the center of the track may complicate how your road wheels will be arranged, but it seems, to me at at least, to be the easiest and most secure way to drive the tracks. I fear the bolts alone will be a dismal failure due to their lack of individual strength and the flexing of the rubber.

[trek]

Originally Posted by RoosterBooster

interesting idea ... but IMHO i think you will run into a couple problems;

your bolted together "track" will not last long (without at least a little overlapping / vulcanizing) ... i would try to find a "one piece" belt loop (bigger tires ?!?)
you will most likely peel the track off the running gear in the first turn (your design has marginal side load support)
to much friction when your "driver wheel" engages the bolts; it will grind them down in no time.
questionable traction of the (worn tire) track.
...


when i grew up in switzerland i was often riding shotgun in "Pistenfahrzeuge" like this;

as somebody else already suggested i would take a close look at that style of tracks ;
rubber loops with cross-ribs and driver "zahn-raeder" (sprockets ?) that engage into the ribs.

thx that whas the name of what i tried to describ: "cross-ribs" that's what you need to hold your bolts to the ruber.

[Steinbruchsoldat]

Originally Posted by Elwenil

Can't help but be reminded of this:


http://www.techeblog.com/index.php/t...iced-at-11-999

If it's going to fit in the back of a minivan, at least what we call a minivan over here, it's not going to be much bigger than a lawnmower.

I`ve never called my L300 a minivan, and i wouldn`t call it that, because it has almost a one ton carrying capacity. The final dimensions will be 47" wide and 138" long...

Originally Posted by WILLD420

You are right that the tire tracks have been done before. What is different is your method of driving them. Internal grousers are a proven design for a reason. They work. Your method lacks the strength that you will need to prevent destruction of the track if the drive wheel should slip, the track lose tension or slip from the rollers or drive sprocket. As you have stated, the pictures above are ideas in the making and plans that are being discarded as they do not work out. This is good.

Yes, i like trying things and look at them in real life instead of just a CAD model. This way i get a lot of good ideas...

Originally Posted by WILLD420

I think you can use the bolts you already have installed, but make connectors between them, with raised cogs to drive on your sprocket. This would spread the load between four bolts, rather than just two, and not add too much complexity or weight if done right. If these connectors were designed that the four bolts were tied together, across the track, then you would gain the stiffness you need in the track for turning, as well as load distribution between 4 bolts rather than only 2 at a time.

If you plan on using rubber tires for your carriage wheels, then you can design them to run inside the connectors, which would be basically an internal grouser, and they would keep the track aligned.

I`m still thinking that the bolts are strong enough. But if not i`ll do exactly what you said. Shouldn`t be a problem to add them later...

Originally Posted by WILLD420

Steering: Is this to be articulated in the center with the steering as that of an articulating tractor? If so, then hydraulic cylinders are the only way to get the strength you need.

As with everything else, you need to do as the professional engineers do, over build it, because you never know what will happen or where you may wind up, and you don't want to build it with the idea that you will always be on a packed trail, with perfect conditions. With cylinders, you will be well served with a joystick control on a valve, unless you want to build an orbital steering setup. Orbitals bring on all kinds of plumbing and mounting issues, whereas a simple hydraulic valve can be very easy to configure.

You`re right, it will be articulated steering using an hydraulic ram. I think i`ll use a normal 4/3-way valve, but outfit it with an self centering setup and a joystick...

Originally Posted by WILLD420

Have you considered using turning brakes on the front portion, and just allowing the rear to follow, as a trailer would do? If you did turning brakes on both the tow vehicle and the trailing portion, you could easily make them work on opposite tracks, thereby forcing your two portions to pivot faster and work with each other, rather than having only one end of the vehicle do all the turning. With turning brakes you cannot weld the differentials solid, but you may gain maneuverability and control that you may not have with just the rams to steer with.

I thought about that but decided against it. First of all it`s a lot more complicated, because i`d have to add brakes on all 4 sprockets. I also think it`d be dangerous if i can`t control the angle between both cars. Just think driving on a slope and the second car starts sliding downhill. The big Hägglund also uses articulated steering and locked differentials. I think with open differentials it wouldn`t drive well, because the tracks need a lot more power to turn, so i think spinning one track would happen a lot...

Originally Posted by WILLD420

We have not discussed your options with regard to salvage yards, or equipment. If you have access to a rural area with agriculture, then you may be able to source a lot of things that will help you build this easier. Otherwise, you are going to have to figure out how to make automotive stuff work. Weight is going to be an issue for you with your desired method of transportation. Have you determined a gross unladen weight target? Have you weighed the engine and drive components you are going to use?

Well, those options are easy to discuss, because we don`t have salvage yards here like you guys do...
But i don`t see any problems with using the automotive parts, it should work well. No idea on weight yet, but it think about 400-500kg. The donor car weights about 800kg, no numbers on individual parts yet...
As said before, my L300 can handle almost one ton payload, so it should be find...

Originally Posted by WILLD420

I looked at your rotor with the drive cogs on it. It's a good example, but the rotor itself will not work as you have done the cogs. Rotors are traditionally cast iron, and unless you are better than average at welding cast iron to steel, the joints will be brittle and subject to fracture under shock loading. The only way I can see that working, is if you drilled a hole through the rotor, tight enough that the pipe would barely fit through, then add gussets from the pipe to the rotor center. This would require heating the rotor, piping and gussets to at least 500 degrees in an oven, then welding and reheating to keep the temp of the whole thing above 500 degrees. Then either bury it in hot sand, or wrap it in blankets so it cools slowly. The key is to allow them to cool at a speed that prevents the two metals, which will contract at differing rates, to cool slow enough they don't stress the joint and crack.

That was just a test, see below...

Originally Posted by Elwenil

I'm thinking that adding angle iron (or aluminum if you prefer) to the bolts as mentioned above and for a drive wheel, a normal wheel of the correct width with round stock or bars of some sort welded across the width of the wheel. You could even go a step farther and use a rim wide enough that the entire track would fit in between the rims sides to help keep it in line and then put the drive bars deeper in the rim. Not sure if I explained that so that it makes sense, but I'm thinking of drive sprockets along the lines of what is used on the Ripsaw:

The drive "teeth" down the center of the track may complicate how your road wheels will be arranged, but it seems, to me at at least, to be the easiest and most secure way to drive the tracks. I fear the bolts alone will be a dismal failure due to their lack of individual strength and the flexing of the rubber.

Like i mentioned above, if the bolts fail i`ll do that. For the sprockets see below...


Ok, so i started with the first real prototype of the drive sprocket today. This is the drawing:



Then i started fabricating it:







Unfortunately i`m missing a 20mm drill bit, so i couldn`t finish it. But i just had to tack some tubes on to test if it works. Well, it fit like it was designed for it...



I`ll add some flat stock between the tubes to center the track, same principle as elwenil mentioned...



I think this is the way to go, i`m really happy that it works like i thought...

[WILLD420]

Looking very good.

If you were to use square stock, rather than round, it would tend to keep the bolt supported better. With a round driver, the bolt will have very little surface area supporting it, and will be more inclined to tilt. The square stock would also strike the bolt closer to the rubber, lessening the leverage on the bolt and the rubber, it might even drive off the nut, making the leverage almost non existent.

As for salvage yards, I encountered a similar thing in New Zealand. I was there 2 weeks and only in the most rural areas, did I find non working autos, or equipment sitting around waiting to be used for parts. The rest of the country appeared to recycle everything that wasn't alive and growing out of the ground.

Very strange for a country boy from farm land to experience.

[Steinbruchsoldat]

Thanks.
Here's a drawing that shows why i think the tubes are better:



Also if i would use square stock, everything has to be perfectly aligned, and i know that i'm not able to do it perfectly...

And for salvage yards, i thought i was in paradise when i went to canada and saw all those scrapyards and the heavy equipment yards...

[rocky66]

you gone bend the bolts under load i think

[Elwenil]

So are you building a low track with no road wheels or bogies or are you building a Christie type track or what? It looks by your diagram above that you are going to do something similar to the lawn mower pic I posted above or are the drive wheels going to be elevated with bogies supporting the weight and the drive wheels only used to propel the track with return rollers or Christie road wheels to support the track? If you are only using a drive wheel and an idler, I think this thing will be very rough riding and will not have the low ground pressure tank treads are famous for.

[matty_fly]

Having worked on some tracked vehicles before, I think that you might be better served by putting your track locator to the inside of the bolts.

I was thinking a V shape on the plate of your drive sprocket to help locate and guide the bolts and keep the disc centered.

If the nylon webbing fails, why not just use another scrap of tire to make the "hinge" of even double up tires and stagger the joints? I also like the idea of plates running perpendicular to your tracks where the bolts go through, it would be an easy way to add some more traction.

[Steinbruchsoldat]

Originally Posted by Elwenil

So are you building a low track with no road wheels or bogies or are you building a Christie type track or what? It looks by your diagram above that you are going to do something similar to the lawn mower pic I posted above or are the drive wheels going to be elevated with bogies supporting the weight and the drive wheels only used to propel the track with return rollers or Christie road wheels to support the track? If you are only using a drive wheel and an idler, I think this thing will be very rough riding and will not have the low ground pressure tank treads are famous for.

I stick to my drawings, a bigger idler wheel, two bogies and the elevated sprocket:

Originally Posted by matty_fly

Having worked on some tracked vehicles before, I think that you might be better served by putting your track locator to the inside of the bolts.

I was thinking a V shape on the plate of your drive sprocket to help locate and guide the bolts and keep the disc centered.

Thats a good idea, i`ll do that. What do you think would be the best design of the plate?

Originally Posted by matty_fly

If the nylon webbing fails, why not just use another scrap of tire to make the "hinge" of even double up tires and stagger the joints? I also like the idea of plates running perpendicular to your tracks where the bolts go through, it would be an easy way to add some more traction.

I can`t use anything bigger then the webbing, because it would change the thickness of the track. But i`m going to add some angle iron to the outside of the tracks in the winter to add some traction...


Oh, and my buddy gave me two of those today:



Let`s see if i can use them...

[Steinbruchsoldat]

Got the hydraulic cylinders today:











This one has a damaged piston, but i`ll use it to control the vertical motion of both cars. This requires almost no pressure, so it`ll be fine...

[Back Woods]

Once that orange banding starts to fray it will pick up every little piece of debris you roll over.

I use it for banding together lumber. It is good stuff.

[Steinbruchsoldat]

Worked on the sprocket today:









That`s my idea for centering it, but i`m not really happy with it. Any better ideas?