What's the point of pto friction clutches?

[Muck Spreader]

Just had to redo the plates a Walterscheid friction clutch on the mower again. As they seem to destroy themselves in seconds just like a set of belts, but are as expensive to replace and a bit more fiddly what is their benefit? Couldn't the same level of safety be archived with a simple shear bolt or cam clutch?

 

[Courier]

They are needed to limit the power particularly now so many folk use tractors with twice the required power to use a machine at full capacity…

 

[bobk]

Just had to redo the plates a Walterscheid friction clutch on the mower again. As they seem to destroy themselves in seconds just like a set of belts, but are as expensive to replace and a bit more fiddly what is their benefit? Couldn't the same level of safety be archived with a simple shear bolt or cam clutch?

Maybe it wasn't set up correctly , got them on 3 power harrows with no grief

 

[Pistonbroke]

They don't like getting wet ,the discs attract water then either disintegrate or lock up. Slipping on the rhino, tightened up according to the book and then blew the one gearbox hitting a lump

 

[Cowabunga]

They are fitted to absorb shock loads by partially slipping when necessary. This is to protect shafts and especially gearboxes from fatigue and torque overloads, mainly from full power relatively slowly rising torque. A square baler may be fitted with such a clutch between the flywheel and the tractor to avoid damage to the tractor's drivetrain by slipping slightly on each full-load ram stroke. Should an obstruction or gross overload occur, then the shear bolt breaks. Call that a 'belt and braces' approach.

 

[MF-ANDY]

A slip clutch protects from gradual over load. A shearbolt protects from sudden overload. This is why most balers have both.