Air clutch idea

[bevans6]

I am having some knee joint issues which make driving my bus with a MCI air assist clutch painful.  While I plan to go completely through the clutch mechanism and optimize it, I am also looking at options to make it very easy to operate.  I met a guy with a S-40 in a MC-9 at one of Kyles non-rally's in South carolina, and he had a manual transmission with an air operated clutch that was controlled with a brake type foot valve.  I was thinking of how to make the same thing.

My idea is to take a single circuit brake valve (Meritor RKN 22600), feed it through a pressure regulator to be able to tune it, and have it operate a Type 16 brake chamber.  The brake chamber would be connected to the mechanical clutch mechanism at some logical point based on leverage, amount of throw required, handiness, etc.  Right now I am thinking of actually putting it under the driver's seat working on the pedal mechanism, that would keep it very easy to access, require minimal modification to the existing pedal assembly and keep the air install very short and easy.  The idea is that the foot pedal would modulate the air pressure to the chamber, which would extend under pressure to activate the clutch, and I can tune the pressure required to push based on how much pressure I feed into the foot pedal.

Does anyone think this might work?  Anyone have a single (or dual circuit I guess) foot valve lying around they don't need, so I can try it?

Brian

[OneLapper]

I've been designing an air actuated clutch system for my 4106 using a brake valve and treadle, regulator, actuator, etc.  I plan on keeping the mechanical linkage.  I haven't figured out the final configuration but the actuator will likely be mounted on the mouse trap. 

[chessie4905]

   We had one in our ACF IC-41 Brill. It used a standard treadle valve and a Rotochamber at the bell housing. From memory it was about 5 inches in diameter. Rotochamber was used to get the necessary travel. The mounting bracket was pretty simple in design and did the job. I did add a restriction to the line to slightly delay the somewhat harsh engagement. It worked pretty well.  I would recommend trying a small shock absorber to help regulate apply  Pressure regulator could be added. Ours didn't have one. Dampened clutch discs could be considered also. In the Bendix document library, there is a listing for a clutch actuator. You might want to take a look at that.

[rusty]

A few years ago when I was starting to think about my clutch assist someone had built one similar to what you are talking about. I know is was tried and was later taken out of the bus. If I remember correctly it was hard to control and had no feel to it.I had also built a bench mock up of one that you are talking about and it was not very smooth. The air assist made from parts that were used to do a clutch assist make more sense to me. Mine clutch is very easy to push and has feel to it.

Wayne

[mung]

Not only does air assist sound like a better idea, I would say that air actuated sounds like a very bad idea.  I don't know that I would want to have the air actuation break and not have a way to push in the clutch.  Not only that, but how are you going to shift the bus without it being aired up?  I keep my bus in first when parked and move it to neutral before I start it.  I kind of need my clutch to work before I start the motor and air up the bus.

[bs4104]

Been there, done that.  Stay with clutch mechanism or go with hydraulic. Bruce

[TomC]

Time for Allison Automatic!

[mung]

Is it worth putting hydraulic on a 4104?

[luvrbus]

Prevost did the work for you with their hydraulic clutch design, Volvo has a nice clutch with the pedal not going through the floor but through the fire wall  ? why reinvent the wheel

[bs4104]

Mung: if your clutch mechanism works just add a air assist unit to your clutch mechanism.
Hydraulic would be best if going from a Auto tran. to manual one where there is no clutch rods mechanism in the bus.
Bruce

[mung]

Yeah, clutch works fine, just a little tiresome on the leg sometimes.

[rgrauto]

I saw an air operated cylinder that tripped the latch on  a dump truck tailgate and thought, if you had a electric valve,such as a air horn valve,etc and a momentary toggle switch mounted on the shifter like a two speed switch it would be a easy air assist for clutch.  With a pressure regulator you can dial in the speed the clutch will operate.You may not need foot pressure at all on the clutch. Maybe someday I'll give it a try.

[robertglines1]

40psi= air assist cyl set on prevost.  FWIW   Bob

[Gordie Allen]

I just don't use the clutch unless starting from a dead stop. Would it be possible to reduce the force required by changing the mechanical leverage?

[Tony LEE]

Have you stripped and lubricated the existing assist cylinder and associated linkages and pivots (and made sure the air supply is actually connected to the cylinder. Just doing that made a huge difference to the ease of using the clutch in our MC8

And have you adjusted the clutch as per the specs.