Project Mini Hägglund

[Steinbruchsoldat]

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...

 

[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...

 

[berg]

subscribed

 

[Steinbruchsoldat]

Worked on the sprocket today:

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

 

[Backroad Explorer]

This is going to be soooooo cooooool !!!!! Hagg's are the s#$%.

 

[seanz0rz]

i see some issues.

the threads on the bolts through the tracks are going to drag on everything, especially the flat plates that help keep it centered, and will wear your drive sprocket badly. an option might be to sleeve them with some seamless tube, and keep them well greased. problem is they will pick up a ton of debris so the wear will be high.

i would also put something that looks like --)|| on your centering plates, basically reduce the sharp edge on that plate to aid in it sliding. -- is your existing plate, ) is some type of curved metal to smooth out the travel of the pin, || is the pin (bolt) on the track.

hoped that all made sense! looks awesome cant wait to see the result!

 

[czarthirteen]

:ylsmoke:

 

[bobDog]

Wow! Unchecked wild ego on the loose....everyone put Protective Ego Gear on.

 

[czarthirteen]

Wow! Unchecked wild ego on the loose....everyone put Protective Ego Gear on.

Wow bobDog......I'm guessing constructive criticism doesn't bode well with you, eh?

Sorry to offend, truly.

 

[Steinbruchsoldat]

Don`t know what was written here, but i`d like to hear your opinions, so i can improve my design...

Made a prototype of the track assembly today. Everything works perfectly, exactly like i thought:

The second track connection is just improvised, but it already works perfectly. I even got a video if you guys want to see it...

Of course i had to take a seat:

I still have to design a centering device for the drive sprocket, any ideas?

 

[78Bronco]

Have you considered using a simple chain bolted to the inside of the tire. I am thinking 81X would work better and it would be able to handle the subaru power easily

http://www.macchain.com/catalogue/catalogue_page15.shtml


This is a very standard chain in forest sector. 11-12 dollars per foot. This is a lot easier tokeep centered on a sprocket.

 

[chilliwak]

Steinez this thing is looking awesome :Wow1:already, and you are not even close to really getting the thing together yet. I have to admire your enthusiasm and your sure fire way to cut through the BS and get it done. All new projects are trial and error. Good on you for using your brain and making it happen. I was thinking that any limited slip differential (rear end) will steer by hitting the brake on one side. This will automatically transfer the power to the opposite side creating a steering effect. The track on one side will turn faster than the one on the other side and thus the whole unit will drive in the direction of the slow track. Have you considered this idea? It might be a simple and easy way to give you some turning ability. Keep us posted on this cool creation with LOTS OF PICS!

 

[Steinbruchsoldat]

Thanks for your nice words.

The steering method you`re talking about is called skid steer. There are a few reasons why i`m not going to use this:

1. I would have to install brakes on all four drive sprockets. This isn`t easy, because i have very limited room there. It`d also be hard to adjust them to equal braking power on both cars.
2. If there`s braking force applied to one track, there`s no power transfered to it because of the open differentials. So i`d loose 50% of power while turning.
3. I`m going to weld both diffs for maximum traction.
4. Imagine driving on a slope without both cars connected. One car starts sliding and turns the other. Very dangerous...
5. The real thing has articulated steering, there has to be a reason they use it...

Btw., i`m going to pick up the donor car next weekend:

1,2l 3cyl 75hp...

 

[Pedro]

can you explain your steering setup? I don't quite understand how it is going to work.

 

[Steinbruchsoldat]

It uses articulated steering between both cars. The same as a wheeled loader or big dumper:

You can see the hydraulic ram in the foreground...

I`ll mount a engine driven hydraulic pump in conjunction with a 4/3 way valve and a hydraulic ram. It`ll be controlled by a joystick...