Manual Clutch for Horizontal Shaft Motor

[Bilboy]

There were lots of motorcycles that ran dry clutches and motorcycle clutches of the 20's to 80's ran on a 2" dia hub with a taper to fit the gearbox mainshfts.
Lots of old WM20's around with a clutch conversion to thrust race & over center lever.
To convert a motorcycle wet clutch to a dry one you simply strip the rubber off the driven plates & glue cork sheeting onto them.

Do you need the unit to be concentric with the end of the PTO shaft ?
Almost any small car clutch can be modified to fit.
The Triumph/BSA 3 cylinder engines ran a modified BMC Minni clutch.

If it is not a commercial secret what exactly are you trying to power.
Ransoms made some very large roller mowers still using a cork clutch.
We use them on cricket pitches down here.

Thank You Bert,

It is not a commercial secret. I have several projects that I have been collecting parts for. Most of them are small off road vehicles. Atvs, garden tractors. go karts, and scooters with manual transmission with manual clutches. I have several centrifugal drive trains, centrifugal clutches, comet type clutches, and comet type torque converters. I want to be able to change gears with a manual gear box, V belt drive won't work for moving and at the same time changing gears as it is hard keep from grinding gears. Cone clutches disengage well but it take great amount of practice to smoothly engage gears without grabbing instantly. I've modified them to allow a reasonable amount of slippage while engaging, engaged they are rock solid and you would have to work very hard to get them to slip under load. Cushman scooter clutches are great for changing gears while in motion they have a manual override throw out bearing but are centrifugal for beginning engagement, but are limited to about 8hp. Differntials will work by using a band brake one side and in the right configuration can be used as a reversing box. Motor cycle clutches are perfect but they are wet clutches and hard to seal in lube unless you are using the engine trans as a whole unit. I have used them several times but the engines can over heat working them at continued low speed. Water cooled motorcylcle emgines are no problem other than price. Dry disc clutches are the are the best for me. Now you have solved my problem with your suggestion to use cork to replace the wet disc linings. Thank You! If the cork has a short usage life I can use automobile used salvaged clutch, brake, or new friction lining material. I'm sure I can find high temp glue or I have tubular rivets and the manual brake relining rivet foot press machine. I can also use dry lawn mower clutches like on my 3813 Honda mower. I have a very large useable collection of machine tools turning, milling, planning, press and leaf brakes, sheet metal shears, rolling and forming machines. spot arc and gas welder, foundry, heat treating and forge. and first of all a large 215# anvil.
I am 72 but I'm not done yet.
As to having my future clutches concentric to the pto shaft; would be best but a jack shaft will work. small auto single disc clutches would work well, I would have to turn out a driven plate (flywheel) to fit pto shafts. Disc brake rotors might work with adaption, they are heavy and balanced.
I'll research dry clutch motorcycles as you have suggested. I am impressed with the ingenuity of Down Under people their ways to make do; some of our small farmers and people who work with their hands are the same, skilled workers here are hard to find. Our manufacturing needs a new supply of skilled workers and industry is trying to train them with new schooling in the manual arts. Hands on people can feel what works and lasts.

Thank You Again
Bill

 

[bertsmobile1]

The reason I asked about the position of the clutch as most of the motorcycle clutches use a pushrod through a hollow main shaft and these are easy to instal.
However you cant do that if like a centrifugal clutch it is on the crankshaft.
Them cranked pushrods are buggers to set right :confused2: .
Up till the 50's most UK motorcycles ran dry, cork lined clutch plates inside an oil filled chaincase ( only a British Engineer would try to do that ) :laughing:
Some Japanese clutches are reverse sprung so you dissengage by pushing from the pressure plate side rather than pushing from the sprocket side.
The BSA/Triumph triples ran a modified BMC mini clutch with a small flywheel.
Lots of parts books on line so you can see how they worked
That clutch would be way over the top for a 20 Hp Briggs, my single spring WM20 clutch would handle that Hp
The only thing to consider is when run dry the plates need more lift so if using a multi plate motorcycle clutch you might need to leave out one set of plates.
A clutch that handles 60+ Hp should handle 20Hp with one less set of plates standing on its head.
The racers who run dry chain cases replace the loose rollers with a double row sealed ball bearing

 

[Bob E]

I don't know, belts and pulleys are cheap, easy, and can be bought about anywhere that sells that kind of stuff.
That said I would like one for the homemade garden tractor I've been building in my head :laughing:

 

[TractorLife]

I’m very interested in this as I’ve built a dune buggy that started as a mower. Weighs in at 1500lbs. Using belts as clutch don’t last long and get broken often. I’m using a 17.5hp Briggs opposed vertical shaft with an 8” pulley driving a 4” pulley on a mst205. Twin chain drive from trans to solid axle, 25” bear claw tires. 1st gear is a monster, pulled a 50’ JLG boom lift (4500ish lbs) though dry loose Florida sand. My understanding is the engine produces 17.5 hp and 45-47 ftlbs of torque. A better solution for a clutch is needed. I’m planning on building a newer version with a better frame design, would like a better clutch in the plans.