Slip vs. Overload "Ratchet" Clutches

[Spudland_Dave]

What exactly are the differences between a Slip Clutch and a Overload "Ratchet" Clutch?

 

[Bedlam]

I know the slip clutch does just that it slip when theres a problem.
I belve the ratchet one is http://www.weasler.com/OEM/PDFs/WeaslerInformationSheetRatchetClutch.pdf
Almost sounds like anti lock brakes

 

[Spudland_Dave]

LOL, I found that exact PDF when googling it....I understand the mechanics of how it mechanically works...

I'm just trying to understand when a person would want to use one version over the other. From what I've read, the Ratchet clutches are relatively maintenance free, and if anything are superior in design to the Slip clutches because of the maintenance issue...
Why is it then that everything on our sized equipment has either a Shear Pin or a Slip Clutch.

 

[GreenWannabe]

As I understand it, the two devices work in an opposing manner. The slip clutch allows the PTO shaft to continue turning (therenby not breaking the shaft or the tractor) when the implement strikes an immovable object and stops turning. The ratchet (or overrunning) clutch allows the PTO shaft to be driven by the implement, such as a spinning rotary cutter, when trying to stop a tractor which has a transmission gear driven pto. This prevents the implement from overpowering the tractor's brakes, thus pushing the tractor.

 

[larso1]

I've got a ratchet style safety clutch on a PTO shaft ( for sale BTW ). You can see it at:

Walterscheid PTO Shaft w/ Slip Clutch

It's a new one, never used so I can't speak about actual operation, except to relate the mfr's info that it is non-adjustable, will only release at the max. pre-set load, and then you turn it a little in the opposite direction (I believe) and it re-sets. This type ratchet clutch has needles and balls as I recall.

Bill

 

[Stimw]

I had a 8-N Ford. When I used my Woods Brush cutter I had to have the overrun clutch. The Ford had the pto shaft connected to the rear axle from the trans output shaft. The Woods was a big flywheel, even if you push the clutch in the tractor kept moving. With the OR clutch the Woods would just coast in stead of drive the tractor.

 

[Spudland_Dave]

Stimw...The ratchet clutch is not an Overrun clutch like you describe...

 

[Bedlam]

Thanks for that clarification Spudland. I was at first thinking they meant overrunning clutch till I found the PDF on it. I never knew it existed..

 

[Spudland_Dave]

I never knew it existed..

I dont think alot do....it really seems like the perfect setup...minimal maintenance like a Shear pin, yet the advantages of a slip clutch by not having to bring work to a stop to replace busted shear pins

 

[rambler]

Never heard of those before, I too was thinking of an over=running clutch. Huh.

I think the slip clutch can last a long time for a person with a little TLC a time or 2 per year. It's adjustable for slightly different conditions.

The newfangled thing is not adjustable? Hum. I've been around farm equipment all my life. when they come up with a new thing that never needs adjusting, no hassles - it typically breaks pretty often & you need to throw it away & buy another one for $$$$.

--->Paul