Another way of looking at the chain size is to consider that the tension in the final chain will be approximately
max traction X (diameter of the track drivers / diameter of the final sprocket)
I'd expect the maximum traction to be something on the order of the weight of the vehicle.
The chain manufacturers publish tables for max chain tension for slow speed drives, which is approximately 1/4 of tensile strength. If you go thru the standard selection procedure you'll end up with a massive chain that's suitable for 24/7 use--the slow speed ratings are probably a better fit for your use. Here's Dodge's version...
formatting link
pt_components/sproc_sel.pdf
Tsubaki gives actual tensile (breaking) strength in their catalog, and a Google search may turn up their catalog online.
Hi . I have a VW driven track machine with chain drives . First off the chains are 60's . More then strong enough to carry 3000 lb over uneven ground and steep slopes . My reduction after the axles is about 5/1 ( I should check this ). Not enough ;-( . I can only use 1st gear , second only on the smoothest ground . The other gears are simply far to fast . I need to do some major rework of mine and will slow it down more then . Mine has the brakes after the reduction , bad idea . It would have been much better right at the axle . I don't really have room to move it now so planning on going over to power brakes and double up my calipers hoping that solves the problem . My tracks are far different then the pictures you posted . Mine are old rubber conveyor belting with metal cross bars for the drive sprockets to engage . I have had mine for 20 or so years and never had to replace the chains but probably will shorten them soon by half a link . If you have any other specific questions ask and I will see if I can help . I can see if about pictures if you like . I really wish mine had an automatic tranny . Things get real busy and shifting from forward to reverse on slopes can be a bit nervy . Well the slopes in BC are for me anyway . ;-) . Luck Ken Cutt
I had a friend who built a lawn mower like this. At the output side of the VW transaxle, he fashioned axle shafts with gears from a coal mine winch, I think. He built an enclosure that bolted to the transaxle and to the frame. He used what he had but I think it was something like 7:1 reduction and in low, I could walk fast than he could drive wide open. He pulled a gang of 10 reel mowers over his 5 acre front yard for over 5 years without a drive train failure. I think the secret to his success was that the gear set was way oversized and he keep them running in hypoid (sp?) gear lub. R. Wink
Don't know about the CD, but the magazine is fun to look through. It's great for a guy who wants to get ideas for building something fun. Also has some good sources of info on products.
Ken, that's one of the answers I was looking for. Great. Thanks.
Again an answer to what I was looking for. I haven't looked in to the specifics of ratios yet. But at least from your experince I can get a better idea.
I was haveing trouble in deciding were to put the brakes. I figured if it was after the reduction that the power transmitted through the reduction that it would be hard to brake. So you think the brakes would be better of if they were at the output of the tranny before the reduction?
I was orginally going to use a drive sprocket put couldn't find a ready source for one. What did you use for a sprocket?
I think the ones I posed here are about it for now. I'll keep your e-mail addy in the address book.
A pic or two would be nice if you can do that. I realy would appreciate it.
I was also wondering if an automatic would work better. I don't have the hills to contend with. Just a 1/10 mile long driveway that gets plugged with snow real fast, plus I don't like when it gets below te 20's and the wind chill way minus.
Again thanks for all the good info. I'm kind of surprised that somebody else has actually tried this. At first I thought I was a bit nuts trying to do this.
My thinking on reduction is why have four gears but only be able to use one or two ? I will try look tomorrow and get the tooth count .
Ideally I think clutches and brakes would be the best choice but for sure I have a hard time braking the way mine is set up . I would put the brakes right at the trans axle if I could . One note . Mine is really hard on the rear spindles and idler wheels . Loaded the side strain is huge when braking . I have to go heavier all around . My original spindles are off a Ford Cortina and I have 12 inch idler wheels . My spindles are welded to heavy tubing that goes from side to side . So changing them is a pain . When I replace them, I am going to spindles that bolt on . There are some Dodge rear spindles that look good at the wreckers . So welding on plates and bolts should make it easier to change them when they do go . I can get spindles at PICKNPULL on sale for 7.99 so I figure I can afford to lose a few and can keep a spare on hand . Then I will also move up to 13 inch idlers and hope they are a little tougher but really if I brake a few rims I do not care . Old Dodge rims here are freebies anyway . It isn't that things brake that often but the side drag is a design issue you can not avoid using only brake steering .
Drive sprocket , ha ha . Mine will surprise you . Center hub welded to a flat plate , then about a piece 1 1/2 inches welded wrapped around that at 90 degrees , Then teeth welded around that made from solid metal . I know sounds like a big pain but really not very hard to do and they turn so slow nothing really needs to be balanced . For sure with teeth they never slip .
The email is good . Just put track machine in the header so I do not dump it with the reg daily spam .
I will see if I can get some pics into the drop box tomorrow . Enough to show clearly the points I have made so far .
I am amazed at where mine will go . I can carry a cord of wood on the back and crawl up hills too steep to stand on . Side note , seat belt , honest they lurch enough to throw you right off the front . Happened to me once , yikes . Now I do have a belt and I will not get on it unless it is hooked up . I can not say how important the belt is so plan for one . My machine I estimate weighs about 1800 Lbs. empty and loaded just about 5000 . This will give you an idea about the power you can expect . If you plan on moving snow weight will be important . I guess mine has some flotation but no where enough to stay on top of snow .
Feel free to ask any questions you have as you go along , these things are way too cool a toy not to share :-) . Luck Ken Cutt
On Sun, 30 Jan 2005 21:48:52 GMT, "Bernd" vaguely proposed a theory ......and in reply I say!:
remove ns from my header address to reply via email
My .002 worth...
Brakes will need to be smaller if before the trannie or any reduction, because they are stopping a much lower torque when the engine is driving, and _with_ a higher advantage if you are "freewheeling" (as much as this thing will ever freewheel ). But if the trannie or any part of the drive train after the brakes should fail, you have no brakes, and also no drive train.
You are right about the braking under power, except that in most cases that I know of, skid steer stuff that is not hydrostatic drive also requires that you disengage a clutch to the stopping side of the tracks before you brake to turn anyway.
If you go back through some of the messages you'll see I posted some URL's that explain how I found out what to use. I was originally going to make my own track using belting and C channel bolted to the belting with a sprocket drive.
But to save you the trouble of searching right away, I'm going to use the rear tire of a farm tractor with the side wall cut out. I think for your application you should be able to use any kind of rubber tire that will fit the length of track you want to make. Just cut the side walls out and use the tread. One problem I'm going to need to solve is keeping the track on the drive and support wheels.
I think perhaps that a conveyor type of belting might work for you. Since I'm familiar with farm equipment I was going to use the belting that is used on round hay balers. If you have a "Tractor Supply" store near you, that is were you can purchase the belting. Think of any kind or tire or belting to make your track out of. Got more questions, just ask. You can e-mail me at bhf51 at att dot com. I may forget to stop back here to check on posts. Best to take it to e-mail. I'll check back just incase you can't get through.
He could set up an emergency brake of sorts. I stuck one on a cart once--it was just a simple parallelogram that would swing down far enough to contact the ground--rolling in one direction would wedge it further into the ground. Two back-to-back for bidirectional braking. Simple, lightweight, damn near bulletproof. Or use auto wheel ends with brakes in 'em and pull like all hell when something goes wrong. (:
I think the transaxle he plans to use has a differential in it, so steering clutches shouldn't be needed--just twin brakes. I believe most crawlers omit the differential because it's hard to make sturdy enough, and it would make it possible for the tractor to drift to one side rather that going straight when digging with only one end of the blade. Shouldn't be an issue on this doodad.
Hi . I did send in pics today but I do not see them in the " drop box " yet . I may have botched it . If they do not show up tomorrow I will try track them down . They will be under the heading of " track machine " if some how I did get it right ;-) . Email any time along the route . Luck Ken Cutt
I have a trans axle but sure wish for them clutches none the less . In fact I consider it a design flaw on mine ;-( . I keep meaning to fire the designer ;-) . Nick is right in my opinion . You can get by without but it is harder on the machine . Cheaper though and a ton less engineering . Also with clutches I could have posi . It is a minor pain but would be nice the odd time . Now if a track spins on steep or sloppy ground I brake that track and it powers through . Just it annoys me . If a chain broke stopping even on steep hill would be no problem . If the tranny failed . Well in my case I think stopping with the brakes would depend on the load . If fully loaded I think it would be time to jump ship and hope the landing spot was better then the crash site ;-) . Normal operating speed is so slow you do have some reaction time . Ken Cutt
But I have never seen it tell you how to build anything. Every article is about like the Jpeg just posted. More like tease articles with a contact name.
That said I will probably buy the CD as I took the magizine for a couple of years and have one of the "Best of Farm Show" books around here somewhere.
Just don't expect anything resembling how to articles..
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