Mini Dozer - Project near complete

[Renze]

hmm... i just read back and deleted my comment about the slackign chains, at it wasnt the track chain but the motor to track drivechain...

An extra bearing might be good. Just dont use V belts, they are just a pain in the @rse. Old 3 ton JF manure spreaders had a belt driven beater, which was a crappy construction because despite the shields, the belts still would catch a bit of muck, causing them to slip every time. V- belts do work, but they need a lot more tension than a chain. So you'd need more bearings, or a bigger shaft anyways.

I do recommend some extra idlers between those main sprockets, the span force is enormous: just imagine you and your friend spanning a rope horizontally over a 5 yard distance, and your 7 year old kid wants to hang in the middle of it: You would need 10 extra men on each side of the rope to keep your kid off the ground at that span width, let alone pulling it horizontally !! Thats whats happening when you drive over a bump, when the tracks are spanned between two rigid sprockets.

 

[ultrarunner]

hmm... i just read back and deleted my comment about the slackign chains, at it wasnt the track chain but the motor to track drivechain...

An extra bearing might be good. Just dont use V belts, they are just a pain in the @rse. Old 3 ton JF manure spreaders had a belt driven beater, which was a crappy construction because despite the shields, the belts still would catch a bit of muck, causing them to slip every time. V- belts do work, but they need a lot more tension than a chain. So you'd need more bearings, or a bigger shaft anyways.

I do recommend some extra idlers between those main sprockets, the span force is enormous: just imagine you and your friend spanning a rope horizontally over a 5 yard distance, and your 7 year old kid wants to hang in the middle of it: You would need 10 extra men on each side of the rope to keep your kid off the ground at that span width, let alone pulling it horizontally !! Thats whats happening when you drive over a bump, when the tracks are spanned between two rigid sprockets.

WE built a lot of equipment with cog belting in place of v-belts and chains... seem to work very well... just a thought

 

[J_J]

Nice work, almost looks like my Magnatrac mini-dozer.

 

[workinprogress]

Well I found the issue today. It seemed the motor mounts may be fine I bent the sub frame. If you look at the first image "Bend Top view" you can see a arrow pointing out the bend. On the other image "bend and proposed plan" which is a view from behind.

Basically I am onto Version 4.0 and will need to straight the angle iron. Weld on additional reenforcement plates (either 1/4 or 3/8 thick) along the angle iron (See image). Along with some spacers and a additional pillow block.

Well like everything it is a work in progress.

 

[rhamer]

When I was a child, I remember the combination of old sprockets and a new chain (or vice versa) on my push bike would always slip for a while under load.

Apparently you are supposed to replace them together and let them wear together.

Are both the chain and pulley new?

Just a thought.

Cheers

Rohan

 

[workinprogress]

Both are new

 

[2manyrocks]

Way cool.

It's odd to me that the bend appears to be outward. I would have thought it would bend inward. Maybe you could weld a cross member between the two sides as a stiffener? You're way ahead of me on this one.

 

[Matt_Jr]

Workinprogress, I noticed your sprocket is not aligned with the chain. The inner portion of the axle is too high (needs more spacing). Is that disconnected there? Also instead of just welding a piece of plate on the angle to thicken it, it would be a whole lot stronger to weld in a gusset there on the top and bottom of the angle too. That would spread the torsional forces along the cross member of the frame(the length of the gusset) instead of just in that one area.

 

[Matt_Jr]

Looking at the last two pictures again, the angle of your axle apears to be the whole problem. I think thats what bent the angle. When the axle was tightend against the inner and outer portion of the frame, that's what twisted your frame. The chain is walking off due to the alignment of the sprocket being off. When you get those little bugs worked out... man that thing looks like fun. And to know you built it, such braggin' right man. Cool project.

 

[Matt_Jr]

Ok, read your last post again, noticed you're gonna put spacers on the pillow block. You were ahead of me. That things gonna be so much fun.