Mini dozer idea..

[Gouldian]

I've seen a few tracked vehicls here . I have a plan rattling around and would like some feedback. I think i can use two peerless differentials driven from a jackshaft. I have a RAGB with 3 forward gears and reverse. Will theae open differentials work with side to side brakes like a skid steer? Thank you in advance for your time and information.

 

[Poboy kartman]

Well. ....I................think........boy.....dozer huh?????.............Man!!!!.......IDKY..............but that seems like such a good idea right now. .............

ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ........

Hey .....Just kidding. .......bring it! !!!!

 

[Gouldian]

After beating on it for awhile i plan to try to step up the speed. I have a fetish for tracked vehicles and this will be a proof of concept for a much larger and scarier project. The plan is definitely not for a creepy crawler. This thing will either fly or self destruct.

 

[OzFab]

I'm not sure I get exactly what you're saying; can you give us a bit more detail?

 

[firemanjim]

I don't think you need 2 differentials. I know a couple guys on here have toyed with the peerless, maybe they will pop in for some enlightenment.....

 

[Poboy kartman]

I have an idea. ....and yes.....but really. ...we'd all like to see and be able to fully comprehend what you have in mind......

I have a feeling what you are shooting for is going to require a very well designed suspension.......

Hate to pry...but.....if you don't mind. ...what is the nature of your disability? ???

 

[Gouldian]

... Hate to pry...but.....if you don't mind. ...what is the nature of your disability? ???

No worries bud. I had my head rattled a few times and sometimes i get a little... Fuzzy...

As for the suspension and use of two drive axles, i think that by mounting the drive axles solid(no movement) and makingmy road wwheels lower, it will mimic the abrams. Then i can copy that suspension design. As far as i have seen, it works well. This will also angle my tracks at each end to make climbing obstacles easier.

 

[Poboy kartman]

No worries bud. I had my head rattled a few times and sometimes i get a little... Fuzzy...

As for the suspension and use of two drive axles, i think that by mounting the drive axles solid(no movement) and makingmy road wwheels lower, it will mimic the abrams. Then i can copy that suspension design. As far as i have seen, it works well. This will also angle my tracks at each end to make climbing obstacles easier.

That's exactly what I thought you were thinking and what I was going to suggest.....PERFECT! !!!! try to mimick the Abrams!!!!

 

[Gouldian]

Started laying out parts on the patio... The only think im not sure of is building tracks and drive wheels. Thinking maybe large roller chain and welding pads across them. I can have the sprockets cut at work on the plasma table.

 

[Poboy kartman]

Do a little looking around here at other tracked vehicle threads....

 

[machinist@large]

Started laying out parts on the patio... The only think im not sure of is building tracks and drive wheels. Thinking maybe large roller chain and welding pads across them. I can have the sprockets cut at work on the plasma table.

If you are just looking for inspiration/ideas for a chain type track, I would look at industrial conveyor type chain. Most of the old Struck brand dozer kit's use that type (not sure about the new one's). They also used multiple v-belts for the forward/reverse final drive's to control each tracks direction (no need for a differential) slipper clutch style.

Another potential way to feather/clutch each track has been designed by a couple of members of the forum. Look up Downs Brothers Racing/DBR manual clutch. I'd love to provide the link, but my tablet and I haven't figured that one out yet.

The one drive type to avoid based solely because of the up front cost is full hydraulic drive. To be reliable, the components are heavy, and they are not cheap. They also get complex extremely quickly. I've got college level industrial training, as well as 15+ years of in the field experience as a maintenance technician; I would approach such a build with extreme caution, and only if the application flat out required it.

 

[fowler]

From my experience with building/fixing a range of tracked earthmoving gear

Firstly we introduce some terms
First u have an engine
The engine spins the trans
The trans spins a diff (musr be full open centre )
The diff powers the SCABs (steering clutch and brakes)
The scabs spin the final drive with is a final gear reduction to the sprocket (bit that drives track)
Usually platenry set but u would use chains

The tracks ae made of 2 parts, links and grousers
The grousers are the plates that the machine rides on
The links make a chain that give u drive and holds the grousers together

The track is tensioned by moving the idler
Which u are calling the second drive axle

The idlers are movable
They are also part of your suspension as it allows the track to change tension
if u run over a log or somthing u want the machine to stat level and let the track frame contort around the log
The really old machines use a big coil spring and u preload it with a nut
This is the method u would use

Somthing like a tank or the tracked tractors use a nitrogen charged strut
So u increase the peesure to set track tension then the gas acts as a spring (in layman's term)

Most machines use a grease adjuster

The rest of the track rides on rollers (what u called ground wheels
This is the complex but in a high speed machine

The rollers are on monor boggies abd they sit in small groups
The minor boggie allows the rollers to articulate for small bumps
They dont gavecany spring on them
Then the minor boggies are attached to major boggies
The majors allow groups of rollers to articulate over big obsticals (like a log)
The majors will require springs maybe shocks

This whole setup is called a track frame and is secured to the machine with bolts or welded
Or is setup to pivot off the frame

Now track design
The abrens tank was designed so if they get in trouble and cant turn around it is as good in reverse as forward

The problem this causes is u have alot of track spining around but only a portion of it is in contact with the ground
Look at a cat bulldozer
The track ground contact is the whole length of the machine for the best grip

The best track for getting places and doing work is what u see most tracked exploration machines use

The fonak drive and sprocket are up high at the front to stay out of the mud and to ginmve a good aproch angle at obsticals
Then the tracks run almost right to the end whee they take a shallow angle up to tbe idler
There is alittle angle to give good grip when climbing

Best place for the final drive is at the back
Ths means all the torwue is being transmitted to the track and us sorta pulling the track from under the machine
This means only the track under the machine is under tension
This increases track life greatly

But this setuo means all the weight is at tbe back and can lead to tbe machine going over backward while climbing

Having all the weight at the front makes a safer machine and puts weight over the front of the machine for better grip while climbing or going over obsticals
This also makes engineering easy as u can have a front mount engine with all the shafts and conections close by in a tight area

No need to run long shsfts or bizarre linkage controls

Ill try to dig up the pics of my moderate speed track frame

 

[firemanjim]

I bet your finger hurts from all that typing...... O wait,.... You might actually know how to type with all your digits.......

 

[Poboy kartman]

I bet your finger hurts from all that typing...... O wait,.... You might actually know how to type with all your digits.......

He has to be. ....how else could you hit so many wrong letters?????

 

[firemanjim]

He has to be. ....how else could you hit so many wrong letters?????

 

[Gouldian]

Fowler, thats is alot of great info. Looking at my original plan, what would happen if i tried to attach drive sprockets directly to my open differential? I realize that under load i would lose power to one side do to slippage and the nature of an open diff. My thinking is that applying a small amount of brakes to the spinning side would even out the load, thus transferring power evenly again.

 

[fowler]

I bet your finger hurts from all that typing...... O wait,.... You might actually know how to type with all your digits.......

He has to be. ....how else could you hit so many wrong letters?????

All done on samsung phone
And yea tiny keys lead to crap spelling

U could atach your sprocket to the diff
But u need some methods of turning

Something like the Argo atv vehicals use this method
The output is taken straight from a diff
Yhen there is large disc brakes on each output
To turn u simply lock up one side

Then to stop go u have a standard clutch on the engine

This is a fairly decent method
But itll cost u
U will requre two large 12in rotors 2 capilers
2 large master cylenders that will be able to activate the caplipers without a vacume booster

The only down side is u cant reverse one track and forward the other
But bulldozers cant do that either
Also the steering inputs wil be quite violent if your not careful

This is the basic ideals behind how id do it though

 

[fowler]

https://www.google.com.au/url?sa=t&...uAIwAA&usg=AFQjCNFASBTcOSMQt7CGxTSCzBgWaf0cnQ

At 3 mins

 

[Poboy kartman]

You do realize that a Samsung phone is the only way that I can get online??????

 

[Gouldian]

Ill have to check my basement, but im sure i have a set of forks and front hub from a street bike. It has duel rotors and calipars. I think i could make some mounts and adaptors to use these. Then two hand brake master cylinders and levers. Hopefully this will allow me to avoid violent directional changes.