oldtin
Reader
2/3/10 1:54 p.m.
I'm looking for ideas on building a duck clutch (clutch actuated by a trigger type button on the shift knob). Set up is a ford 302/T-5 (currently has a push style slave cylinder). Was thinking of a linear actuator/motor with a trigger pull = distance rather than power - but perhaps the actuator is too slow. Where should I look for bits to make it work
Anybody got robotics/motion control experience/ideas???
I don't know, but do they run similar set-ups for handicap modified vehicles? Perhaps there's a supplier for hand-control mod companies that you could buy parts from...
oldtin
Reader
2/3/10 2:49 p.m.
I've only seen one by elap (same as guido-simplex)- high end stuff like was built for Alex Zanardi after his big crash. Seems like a simpler version for an h-pattern box should be relatively easy - I'm just not familiar with the kind of parts needed to make it work.
Nashco
SuperDork
2/3/10 2:57 p.m.
What about sticking with hydraulics and using a hand operated master cylinder, similar to a motorcycle, on the shifter? By fiddling with the bore sizes and lever ratio, you might be able to get it to a low enough effort level to do with your hand; if not, you could use a vacuum booster like a brake system uses. This is assuming you want to make it yourself instead of just buying the off-the-$helf stuff.
Bryce
oldtin
Reader
2/3/10 3:28 p.m.
Def. thinking diy - elap stuff starts at about $3k. I like the idea of having the feel of hydraulics/handle - was originally thinking like a video game controller trigger as actuator with a linear motor/servo/pneumatics????
Per Schroeder
Technical Editor/Advertising Director
2/3/10 3:34 p.m.
Maybe something like a Pingel air shifter from a drag bike?
Trouble is you don't really want an on/off switch to control a clutch, do you? You'll need something that at least allows you to control slip and how quickly it engages.
I think Bryce has the right idea, some sort of M/C master cylinder and a brake booster - there aren't any motorcycle M/Cs out there that I know of which shift enough fluid to handle a car clutch. Even the BMW twins which have a car-type diaphragm clutch, have a far smaller clutch than you'd find in a car.
IIRC the NSU Ro80 had both a clutch and a torque convertor coupled to a manual box. The torque converter took care of getting the car rolling and a switch in the gear lever disengaged/engaged the clutch. That would probably work but I'd expect this to be a major engineering job.
The VW Automatic StickShift used a vacuum diaphragm to make it work. Maybe you could use air brake servos and a vacuum pump/reservoir, similar to Per's air shifter idea. Should be fairly simple to come up with a bleed off valve for the hand control.
oldtin
Reader
2/3/10 3:49 p.m.
Hmmm, what about a servo or high-torque motor under dash - driving the clutch master pushrod - operated by trigger on gear shift or paddle type switch? How much force would be needed? If a pedal has something like a 5:1 mechanical advantage and has something like 20lb of force to operate - motor would need to push 100lbs right???
I've seen rock crawling guys that use a motorcycle assembly on the shift lever. Seems to work well.
T-birds from the 50's / 60's had a remote brake booster that might work for you.
Single circuit M/C feeds a cylinder with a vaccum booster attached that is located down on the framrail. This feeds the brake system.
It's called a Hydrovac: http://cardone.com/Imagesftp/51/518057-01.jpg
Cardone still lists them in their catalog.
If it boosts brakes, it can boost a hydraulic clutch as well.
Shawn
JimG
None
9/14/10 4:33 p.m.
Are you still looking to automate your clutch ?
I used to install guido simplex equipment in sports cars.
I might be of some help.
Jim G
toodamnfunky@comcast.net
I think the Audi rally cars used power steering pressure to directly actuate the clutch pedal. I say that, because they also used the power steering pump to drive the alternator (trunk mounted).
From what I've gleaned, you did NOT want to have your foot near the clutch pedal when you hit the button on the shifter!