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PTO shear pin replacement with a clutch system ?
Moderators: toaddog, TWISTY, V8Patrol, Moderators
PTO shear pin replacement with a clutch system ?
I believe some one posted an article on fitting a clutch to their pto winch drive so you can do away with braking shear pins and more to the point trying to remove the sheared pin and fitting a new one while the truck is in mud, water or even with its nose buried
worthog who likes to play in the mud, just follow me, if you can
I am actually going through this right now , because i have shifted my pto so far in i carn't really get to the shear pin to replace it anyway , so im making a slip clutch arrangement.
I bought a torque limiter slip clutch for $90.00 , from a place near Dandenong in Melb , called Tsubaki Power Transmisions , they were the cheapest for the same item . Im sure if you ring around your bearing suppliers and power transmission suppliers, in New Zealand you will find one.
But to buy a torque limiter coupling they are about $250.00 with a pilot hole in them only ,so you have to machine it to size or pay them extra.
I didnt get the coupling cause i am making my own, the torque limiter
( slip clutch ) ive got is rated from 20Nm min to 75Nm max , i roughly worked out that i will need about 55-65 Nm to power the winch to get about 8000lb , the thing with it is that it is basically a disk pressed between two fibre disks and the way you increase pressure is by tightening or loosening a nut that applies more or less pressure on a cup spring ,
so it is critical to keep this unit out of the mud and water and oil leaks so it must be housed properly and sealed.
Also you must have a bit of room because mine will be a cylinder about 200 long and about 125 od , thats housed , if you just want to run it as is not housed it will be about 65mm long and about 90 od .
But a slip clutch is definetly the way to go , you can set it exactly to slip at whatever lb's you want and you will never have to worry about a shear pin again !!
I bought a torque limiter slip clutch for $90.00 , from a place near Dandenong in Melb , called Tsubaki Power Transmisions , they were the cheapest for the same item . Im sure if you ring around your bearing suppliers and power transmission suppliers, in New Zealand you will find one.
But to buy a torque limiter coupling they are about $250.00 with a pilot hole in them only ,so you have to machine it to size or pay them extra.
I didnt get the coupling cause i am making my own, the torque limiter
( slip clutch ) ive got is rated from 20Nm min to 75Nm max , i roughly worked out that i will need about 55-65 Nm to power the winch to get about 8000lb , the thing with it is that it is basically a disk pressed between two fibre disks and the way you increase pressure is by tightening or loosening a nut that applies more or less pressure on a cup spring ,
so it is critical to keep this unit out of the mud and water and oil leaks so it must be housed properly and sealed.
Also you must have a bit of room because mine will be a cylinder about 200 long and about 125 od , thats housed , if you just want to run it as is not housed it will be about 65mm long and about 90 od .
But a slip clutch is definetly the way to go , you can set it exactly to slip at whatever lb's you want and you will never have to worry about a shear pin again !!
frp88 wrote:do you think that 75m/n is enough i would have thought more to get your pull toque up to 8000lbs is yours thomas or toyo
No i dont really cause it does sound pretty low , but i i got a few engineers to work it out mathamatically and a gear design place regarding the worm drive to work it out and they all came back with a figure around there .
Once it is complete which should be mid next week i have the ability to use a huge load cell at work so i will anchor the winch at one end pull the cable out and attach it to the load cell and use a torque wrench to see exactly what it gets to and then i can also set the slip at the right point .
I couldnt check it before hand cause the load cell wasnt ready , also i have the ability to double the capacity of the slip clutch by adding a second cup spring .
I will keep you posted with exact figures as soon as i get them , but i also reckon it does sound horribly low aswell, we will soon see if these engineers are worth there salt !!
And its a yota pto.
sounds about right couldnt remember the torque figures i just purchased mine from power autos in Dandenong they make all the parts for thomas pto told em what i wanted and then got the coupling of them you have to machine the coupling to the id hole you need and away you go i havent worryed about a sheild yet time will tell haevnt been home much lately
Dont be scared give it a go
sounds about right couldnt remember the torque figures i just purchased mine from power autos in Dandenong they make all the parts for thomas pto told em what i wanted and then got the coupling of them you have to machine the coupling to the id hole you need and away you go i havent worryed about a sheild yet time will tell haevnt been home much lately
Dont be scared give it a go
This is a pic of the coupling you can make out the two friction discs that the drive plate goes in between and the big nut which varies the tension.
These are the components that i am making which are still unfinished , the plate with the holes in it is the drive plate , and the billet is what my drive plate bolts to and that will attatch to one end of the split pto drive shaft.
Drive disc sandwiched between friction plates.
This is how the drive plate will bolt to the billet , which i still have to machined to spec , but will be soon.
im making my coupling because it costs me nothing but like i said above you can pay $250.00 and youve got it ready to go.
These are the components that i am making which are still unfinished , the plate with the holes in it is the drive plate , and the billet is what my drive plate bolts to and that will attatch to one end of the split pto drive shaft.
Drive disc sandwiched between friction plates.
This is how the drive plate will bolt to the billet , which i still have to machined to spec , but will be soon.
im making my coupling because it costs me nothing but like i said above you can pay $250.00 and youve got it ready to go.
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