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LT230 PTO DIY kit possibly on its way


Soren Frimodt

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I think we're probably on the same page?

I was just trying to come up with a real world example of something that works with similar (in this case higher) torque but has similar dimensions. Most people have trouble visualising magnitude of forces and strengths of materials - so a similar example serves to illustrate it.

I'll not pretend that I can run Finite Element Analysis in my head - but I can on the CAD and on the whole, the results have been backed up by experimental evidence.

I don't know why we are arguing over this - I think we are both saying pretty much the same thing and getting bogged down in the minutia of how accurate what for both of us is little more than a guess will be in reality.

Ultimately the best option is to try it. I think that at the very least, our 'guesses' give sufficient grounds for trying it out as the forces/strength is definitely in the right ball-park.

Si

Yes you are correct Simon, and I apologise to Soren for taking your thread off in a tangent, and wish you the best with developments.

Bill.

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I like the idea of being able to split an LT230 so you can have open diff, locked diff, and then disengage the front prop for RWD. There was a chap on Pirate who hacked up a box to give selectable front/rear drive for digging (popular trick over there it seems) but it wasn't pretty (by his own admission the truck was a trailer queen that leaked like a sieve).

One for when I have a load of free time I guess, ha ha ha!

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Sorry to hyjack your thread (again) Soren, i'm really looking forward to seeing how your building your winch.

I'm useing a dana 30 axle to make mine out of, as they have lots of ratios and are fairly light. but i'm stuck for a nice solution to the brake, i wish to make an automatic brake as i have a hydraulic disc setup on my current winch and having to "think" to apply the brake has been dangerous a few times.

If you were to drive into the pinion from the PTO then use one of the wheel drives to connect to your drum and fit a disk brake on the other (with an open diff) you could slip the brake to vary the speed of the line. Release the brake and you have freespool / disengage.

As usual Si simple and effective, but with this setup you would be driving with the planetary gears, don't you think this would cause a lot of wear and heat?

I've considered the same setup you describe but with an arb center in the diff.

So with the arb engauged i have full drive and i can use the disc brake, and with the arb disengauged i'd have a freespool that i could still brake if i chose, but still no automatic function for this i was thinking a ratchet and pawl with the pawl relased pneumatically with the arb is allowing freespool.

Ratio wise, you get 20,000Lb pull for 470ftlb of torque into the pinion. 1st gear on an R380 is about 3.3:1 so to get 20,000 Lb pull, you need an engine torque of 142ftLb

which is achievable with most engines.

Speed wise, at 1000rpm on the engine, it gives 44ft/min. A stock 8274 with no load runs at about 70ft/min.

1000rpm in first gear low gives a wheel speed of 230ft/min based on 35" Tyres - so actually, to be able to pull in at the same speed as you are driving (assuming 100% traction) the reduction to the drum would be closer to 1:1. Alternatively, with the diff setup, you could just use a 6" or bigger diameter drum I guess.

Si

How did you get 20,000Lb from 470ftlb? i couldn't find a formular to turn input torque into line pull.

i'm looking at a 3:5 diff on a 110mm dia drum with the optimal line speed being on the 3rd wrap @160mm dia to give me matched wheel to winch speed (assuming 10mm steel cable with the correct fleet angle to auto spool)

Here's a pic of a very sucessful russian setup, that i've been using as food for thought.

2007-06-02-07h26m40.jpg

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I like the idea of being able to split an LT230 so you can have open diff, locked diff, and then disengage the front prop for RWD. There was a chap on Pirate who hacked up a box to give selectable front/rear drive for digging (popular trick over there it seems) but it wasn't pretty (by his own admission the truck was a trailer queen that leaked like a sieve).

One for when I have a load of free time I guess, ha ha ha!

I think you maybe referring to Sam Overton from Outerlimits in Australia.. He used the front wheel drive housing, shaft and difflock dog clutch from an LT95 and fitted it to the rear output of the LT230. Can't remember exactly how it was done, but probably used an LT95 side gear for the centre diff rear output and an additional front output shaft.. Both shafts would have been cut and machined to fit together so that the dog clutch teeth were against each other so that the collar would make and break the connection between the 2 shafts. No hand brake or speedo drive unfortunately.

Bill.

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I've considered the same setup you describe but with an arb center in the diff.

So with the arb engauged i have full drive and i can use the disc brake, and with the arb disengauged i'd have a freespool that i could still brake if i chose, but still no automatic function for this i was thinking a ratchet and pawl with the pawl relased pneumatically with the arb is allowing freespool.

Here's a pic of a very sucessful russian setup, that i've been using as food for thought.

2007-06-02-07h26m40.jpg

Dan,

Do you want braking whilst free-spooling out, or just a mechanism to stop the drum un-winding? the pawl on the photo above looks like it'd be pretty effective, and a sprung-on, pneumatically released pawl would give the free-spool performance you want whilst still being safe?

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How did you get 20,000Lb from 470ftlb? i couldn't find a formular to turn input torque into line pull.

If you have 470ftlb into the pinion, you get 3.54 x 470 = 1664ftlb at the drum. Assuming the drum is 2" diameter, that equals 470 x 12 = 19966 Lbs pull (1 foot = 12 inches, the radius of a 2" drum is 1")

Although the Pawl idea looks simple, what happens if you stick the gearbox in reverse? OK, you could use the reverse light feed to lift the pawl, but could it do this while the winch is under load? Imagine you are hanging on the rope and all that is between you & death is the pawl - but you need to lower yourself. How do you relieve the tension on the pawl? OK, you drive forwards a little then release the pawl then in the instant before you go into freefall, push the clutch and jam the box in reverse? You just miss getting it in to reverse then.......................they carry you away in a body-bag. Doesn't sound my cup of tea!

You either need the same kind of arrangement as most winches have with a brake which is engaged by the line paying out faster than the motor, a worm drive which will not run away or a brake you can operate independently.

Si

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Could a pneumatically or electrically operated handbrake be used? A disc or drum on the end of the winch shaft, obviously it would have to be up to the task size-wise, but I'd have thought (without doing any maths as I can't :P) that a smaller-scale X-brake sort of thing would be doable. Probably better to make it fail on rather than off as well.

I guess it would suffer from problems of mud/water ingress reducing it's effectiveness. But the design could be modified to incorporate a much coarser friction interface than a standard service brake, owing to the fact that it shouldn't need to be used in while in motion except in an emergency. Electronically it would be fairly simple to set it up so that the brake is only released when spooling in or out.

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But as Si has stated earlier, the wheel brakes will be connected to the PTO, and therefore the winch, so long as the PTO and gearbox are engaged of course. So in essence a brake is really not needed when you winch the car fitted with it. But when you winch others, with your car stationary it will be necessary. But for this you could just use a manual controlled hydraulic disc or drum brake.

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Oh, and a barely noticeable progress has been made on the winch:

post-9137-0-58179100-1318526635_thumb.jpg

But sadly we haven't received the adapters yet, so prices will have to wait a bit more, although I can you give some idea, initially we had hoped, and aimed for a price sub 200 quid, but I'm afraid it's gonna end somewhere nearer 250 instead.. But this is NOT the final price and we will see what we can do, depending of course, a lot on how large a batch we can run.

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Soren, I'm assuming any axle will be able to be used in this sort of setup....? A LR diff is a pretty big lump to try and locate somewhere on the vehicle. Do you have any further plans as to where it will fit etc?

Sorry if I am asking for spoilers, just tell me to get lost if want :moglite:

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We're not sure what to do, brake wise yet.

My initial thoughts went at that ring gear, there is no pinion driving it right? Cos without lubrication I doubt it'll be very good for very long..

There is a pinion driving the ring gear, my thoughts were the same as yours, except that that winch has seen a lot of use without failure as far as i know.

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Although the Pawl idea looks simple, what happens if you stick the gearbox in reverse? OK, you could use the reverse light feed to lift the pawl, but could it do this while the winch is under load? Imagine you are hanging on the rope and all that is between you & death is the pawl - but you need to lower yourself. How do you relieve the tension on the pawl? OK, you drive forwards a little then release the pawl then in the instant before you go into freefall, push the clutch and jam the box in reverse? You just miss getting it in to reverse then.......................they carry you away in a body-bag. Doesn't sound my cup of tea!

You either need the same kind of arrangement as most winches have with a brake which is engaged by the line paying out faster than the motor, a worm drive which will not run away or a brake you can operate independently.

Si

You've miss-read my post, i want to have a disc brake at the other side of the diff and a ratchet and pawl.

For my intended use the mech winch will be used along side my current electric winches, i can use them for the winch gymnatsics and only really use the mech for long pulls.

With how tall the gearing will be in mine i don't really think it would even be that usefull as a static recovery winch.

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Soren, drum looks tidy. For that diameter of drum, a Land Rover diff is about right. Another possible option is a Jaguar diff (which also have inboard disks and nice easy bolt together drive flanges. Using both disk brakes you can use one to control the in speed / freespool and the other as a brake for the out speed.

If you were to use a 2" drum, a much smaller diff - like a Suzuki Vitara Front would handle the 1600ftlb torque. LR should be strong enough for 6" and 20k Lb pull.

Si

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