Trailer modifications / Small pulley wheels / Hydraulics

[oldcorollas]

eg
http://www.nachi.com.au/pages/produc...categories.php
http://www.nachi.com.au/pages/produc...ar_contact.php
twin seal, angular contact bearings http://www.nachi.com.au/pages/produc...act_seal_2.php

http://www.nachi.com.au/pages/produc...?bno=5200A-2NS



conical spacer = small cone to go under the bearing, so it centres the bearing on the bolt and keeps the pulley off the surface

[Slim]

Thanks for that OC. I see now. That site i pretty freakin' good, i must say.

So i'll need to do some machining of my pulleys but i reckon i could make one of those smaller ones fit (like in the 4th link)... assuming they're up to the task. I will need to try and calculate the sort of loads that they will need to withstand.

I would think that i could probably exceed their stated capacity by a bit considering that they're only going to turn at 10rpm at most... and only do it 5 times a year at most.

["Z" UTE]

If you were to go hydraulic, the rams would have to "fail" to the normal towing position.

I could not imagine an engineer or RTA being real happy with a ram that has to have pressure applied during towing. There would be way too many things to go wrong, ie. power supply severed, fluid pressure line leaks, ram seal fails.

That being said, start "thinking outside the box", and I am sure there would be a couple of brilliant ideas that would sort this out.

cheers Chuck.

[Slim]

If you were to go hydraulic, the rams would have to "fail" to the normal towing position.

I could not imagine an engineer or RTA being real happy with a ram that has to have pressure applied during towing. There would be way too many things to go wrong, ie. power supply severed, fluid pressure line leaks, ram seal fails.

That being said, start "thinking outside the box", and I am sure there would be a couple of brilliant ideas that would sort this out.

cheers Chuck.

Take a look at the pics and you'll see that the box, of which you speak, was already thought out of. No-one in their right mind would rely on a cable either. When the tray is lifted up fully there's a big catch on each side that locks into place. It's the big hooked catches that take all the load when towing.

[AAAAGZE]

what you'd be looking for is a 'sheave' not a pulley.

a brass bushing will be self lubricating, and decrease effort required immensely.

tried pushing a dumpster? they have no roller or ball bearings, just a brass bush, and they're a couple hundred kilos full, but roll really well.

here's a link to one or two possibilities.

http://www2.blackwoods.com.au/infoBA...4142&P=2026692

http://www.keblestrading.com.au/winches.html

http://www.jgtrading.com.au/Our-Prod...-AISI-(1).aspx

the last one is a link to a company that i have an account with. the first sheave on that page will almost be perfect.

stainless so it won't rust, and brass bushing for smoothness.


-dave

[wilbo666]

A bit outside the square, but what about getting new 'centre' bits made up out of brass / bronze, and then machining the pulley so that it can accept a seal at the top (I.e. increase OD for 5/6mm etc depth to allow seal sit flush with top of pulley)

Use a single seal (Or could use a seal top and bottom)..pack with grease, assemble and the seal/s should protect from weather conditions...!

Suspect would be magnitudes cheaper than multiple bearings?

Cheers
Wilbo

[Slim]

Hmm... Dave, that last link does look interesting. I wonder what kind of axle i'd need to make for it to run on. At the moment the pulleys, or sheaves as you say, use the bush thingies as the axle. The bolts tighten down on them and supposedly hold them in place. Whatever the replacement is it will need something for the bolt to tighten hard against.

[af300e]

I think there is a danger of over-capitalising here. Double row bearings cost a bomb as would new stainless pulleys etc.
Brass bushes are ok, but the cost of maching both the bush and the pulleys, plus the seals and the added complication of the machine work to fit seals will easily bring the cost up to ball bearing level. When fitting a brass bush with interferance fit, the ID changes after fitting and they have to be reamed out. It's a nightmare.

Single row sealed ball bearings FTW. $10 each plus a little machining of the pulleys and some bolts. A spacer each side of the bearing that allows the bolt to tension against the centre of the race will sort any binding issues. For less than $200 you'll be done.

I bought a double row spigot bearing once and it was $45 vs $9 for a single row. Then I ended up using the single row. Anus still sore from that one............

[AAAAGZE]

Hmm... Dave, that last link does look interesting. I wonder what kind of axle i'd need to make for it to run on. At the moment the pulleys, or sheaves as you say, use the bush thingies as the axle. The bolts tighten down on them and supposedly hold them in place. Whatever the replacement is it will need something for the bolt to tighten hard against.

This will by far be the easiest thing.

buy bolts that have about 1mm longer plain shank than the thickness of the pulley, so it clamps on the plain shank, so it can't compress the rotating component.

or you could use shoulder bolts like these:



pricewise, i could do the sheaves for around the 10 dollar each mark.

i can also supply the relevant bolts and nuts.

-dave


.

[AAAAGZE]

I think there is a danger of over-capitalising here. Double row bearings cost a bomb as would new stainless pulleys etc.

nope, new stainless pulleys around 10 bucks each including GST.

Brass bushes are ok, but the cost of maching both the bush and the pulleys, plus the seals and the added complication of the machine work to fit seals will easily bring the cost up to ball bearing level. When fitting a brass bush with interferance fit, the ID changes after fitting and they have to be reamed out. It's a nightmare.

why go interference fit? problem solved with shoulder bolts. a little bit of play shouldn't affect the pulley operation drastically.

Single row sealed ball bearings FTW. $10 each plus a little machining of the pulleys and some bolts. A spacer each side of the bearing that allows the bolt to tension against the centre of the race will sort any binding issues. For less than $200 you'll be done.

I bought a double row spigot bearing once and it was $45 vs $9 for a single row. Then I ended up using the single row. Anus still sore from that one............

ouch.


.

[af300e]

The stainless pulleys are yummy, but they still run on bushes. I know they are brass and what not but road grime, especially when wet, is full of grit/sand etc and these are bound to become loaded with shit. Then they become a maintenance issue.
No doubt these pulleys are designed for maritime use where sand/grit is not an issue.

Do they run a lip seal or anything?

[Slim]

hmmm... decisions. I am a little worried about the dirt issue. They're gonna cop a fair bit of dirt, sand, dust and water laiden with all that kind of shit. So it's gonna find its way into the bush eventually.

I only want to do this once.

[allencr]

I only want to do this once.

How often has it been done in the past? With copious amounts of lube, routine maintenance shouldn't be much more often then it is on the wheel bearings & winch & hitch, even though you have let it go and the surfaces are not smooth & badly corroded, they're fixable.


Does the wheel throw lots of water & grit directly at them?

[Slim]

I only want to do this once.

How often has it been done in the past? With copious amounts of lube, routine maintenance shouldn't be much more often then it is on the wheel bearings & winch & hitch, even though you have let it go and the surfaces are not smooth & badly corroded, they're fixable.

I personally haven't done it before but when i was at Winton Raceway for the 6hr I met an RACV bloke that had the same trailer.



He was there to tow one of the broken TA22's home. I made a comment about how easy his one appeared to operate. He said that they use it regularly and have to completely strip it down, clean and grease everything every two weeks too keep it working nicely!

Does the wheel throw lots of water & grit directly at them?

Not specifically, but it is being towed directly behind another car and none of the mechanism is shielded or covered in any way.

[SilverRA23]

off topic.. where did you get your trailer from Slim?