electric/hydraulic handbrake
Discussion
There isn't really room for a vertical hydraulic handbrake in my car, unless you put it in the navigator's footwell; and my elbow goes where the navigator's chest is if I try to use the normal handbrake lever. I'm trying to invent an alternative electrical system instead.
The idea is an ordinary mastercylinder actuated by a solenoid at the push of a strategically placed button. The cylinder & solenoid can be mounted on a frame which can sit out of the way. What sort of solenoid will I need? - pitch will have to be about a cm, but what sort of force - my guesstimation is 20kg, based on a 2kg pull by me on a lever with a 10:1 ratio = Does that sound a reasonable figure for what we do with our handbrakes?. Would a starter motor solenoid be strong enough? The ones for door locks presumably too weak. ?This might do?[url]www.mechetronics.co.uk/pdfs/GA5050[/url]
Any thoughts from the brains trust?
How does a Mercedes parking brake work? I've had a suggestion that I could midify one.
The idea is an ordinary mastercylinder actuated by a solenoid at the push of a strategically placed button. The cylinder & solenoid can be mounted on a frame which can sit out of the way. What sort of solenoid will I need? - pitch will have to be about a cm, but what sort of force - my guesstimation is 20kg, based on a 2kg pull by me on a lever with a 10:1 ratio = Does that sound a reasonable figure for what we do with our handbrakes?. Would a starter motor solenoid be strong enough? The ones for door locks presumably too weak. ?This might do?[url]www.mechetronics.co.uk/pdfs/GA5050[/url]
Any thoughts from the brains trust?
How does a Mercedes parking brake work? I've had a suggestion that I could midify one.
I doubt a solenoid would work. Typically their force increases with travel so it's at a maximum when they're fully "shut" but it drops off dramatically as they are drawn out. I guess you might have to pull on the lever with a force equivalent to 20kg or so to make the wheels lock and the lever has a leverage ratio of maybe 4 or 5 to 1 so let's say 100kgf down the cable(s). Obviously, you can reduce this force in a hydraulic setup by changing the bore of the master cylinder but only at the expense of increased stroke. Solenoids have pretty lousy strokes.
Some current Jags have electric handbrakes and don't know how they work but I guess it's a linear actuator. You could try RS components for one but they're not cheap. In any case, I don't know how quickly they can engage. They might not be much use for handbrake turns!
Remember handbrakes must be "maintained on by purely mechanical means" as far as the law is concerned.
Some current Jags have electric handbrakes and don't know how they work but I guess it's a linear actuator. You could try RS components for one but they're not cheap. In any case, I don't know how quickly they can engage. They might not be much use for handbrake turns!
Remember handbrakes must be "maintained on by purely mechanical means" as far as the law is concerned.
Avocet said:
......Remember handbrakes must be "maintained on by purely mechanical means" as far as the law is concerned.
This means a solenoid would have to pull the brake off. Unless you made it such that the mechanism went 'over centre' the solenoid would be continually holding the brake off until it had a loss of power.
In order to prove the validity of your installation to the SVA or MOT inspector I would go find an electric version from a scrap car.
Steve
I am still keeping the cable operated parking brake, so no MOT problems. There isn't room to use it while driving though.
There is very little room in a Stratos for anything! so alternative levers are difficult and there's absolutely no room for another pedal. The Group IV factory cars had a horizontal lever pivoting on the steering column and acting via a cable onto the balance bar - I've thought about this, but the thought of doing a four wheel lockup instead of a rear one doesn't appeal, so I thought I'd look at other solutions.
Does anybody know if these renault/jag electric parking brakes work via the hydralics, or direct mechanically?
There is very little room in a Stratos for anything! so alternative levers are difficult and there's absolutely no room for another pedal. The Group IV factory cars had a horizontal lever pivoting on the steering column and acting via a cable onto the balance bar - I've thought about this, but the thought of doing a four wheel lockup instead of a rear one doesn't appeal, so I thought I'd look at other solutions.
Does anybody know if these renault/jag electric parking brakes work via the hydralics, or direct mechanically?
Edited by jimmystratos on Saturday 6th January 14:41
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