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Cone Handbrake conversion?


simonr
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I have an idea for using a cone brake / clutch in place of a disk & caliper for a handbrake conversion.

Why? Well, it would be a lot smaller diameter (120mm instead of 230mm). This would be an advantage as I could make one for vehicles where the bottom of the transfer case is lower between the chassis rails.

I reckon it could be a bit lighter (7kg in place of 10kg for an X-Brake and 15kg for the drum).

I've come up with a design for a fully sealed expander mechanism which will push the cones together so it should survive mud & poo pretty well. Mud will get inbetween the cones, but it should centrifuge out as it does with a disk, just not as quickly.

Both cones would be made from steel without any additional friction material in between. Although this would allow the cones to wear, the amount of metal in contact should make them very long lasting.

There is a public perception that disks are better than drums (and they are), but I wondered what the perception of cones is? Particularly with the Superwinch EP series using cone brakes.

If you were looking at such a thing, what would your thoughts or concerns be?

TIA

Si

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I know nothing about cone-brakes, as I suspect is the case for many others - you don't see them on cars so they're an unfamiliar/unknown thing. Whether that's an indication of their limitations, or whether punters would assume that's an indication, I don't know.

Would it add any length to the unit? As-is the X-brake tucks in nicely in the space of the old handbrake, a cone sounds like it would be deeper?

Another wild guess but would a cone be more expensive to manufacture than a disc or drum? Or are they off-the-shelf and about the same price? Would people trust the spares supply as they're not something the local LR shop is likely to stock.

Sealed wet brakes (an agricultural / construction thing) are something I stumbled over while pondering brakes for the 109 and struck me as a good idea but I'm guessing they're either expensive, complicated or otherwise unsuitable for a road-going vehicle.

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I do believe old fantic trials bikes used them its been a long time since i had mine but i have a feeling it might of been a cone brake.

I worked well and never gave me any problems probably why i dont remember it much :ph34r:

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....but I wondered what the perception of cones is?

Bike back pedal brakes are cones - I don't think I have ever seen

one of these go wrong. Infinitely more reliable than any other bike

brake system - just not compatible with derallier gear systems,

I think you could get a Sturmey Archer type planetary gear hub

with an integrated back pedal brake - but now I'm showing my

age.

They are a little less subtle than rim brakes ;)

ttfn

Matthew

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Didn't know that's what was used in back-pedal brakes! Learned something new!

Andy, I would hope it would be similar to when you get a small stone trapped between the pad and disk. It will either crush or dig in to both surfaces - but it will still work.

My design has an inner, moving cup shaped cone with the drive flange and prop bolted on either side of the base - so it wouldn't be any thicker than the disk or drum.

I have no idea on costing, however, I doubt it would cost more - and at the moment, i'm beholden to a single supplier of Calipers. I don't like only having a single supplier of anything. At least if the whole thing is manufactured by X-Eng, there is quite a choice of CNC companies able to do the work.

As for spares availability - same applies to the X-Brake, or any other non LR part you buy.

One concern is that the two cones might rust together? Nick (Rogue Vogue) suggested making one half out of Aluminium and the other out of steel which is a common config for cone clutches as they tend not to rust together, nor bind. That of course means the outer Al bit can be Anodised! BLING!!!

I think I would leave the LR versions the same as they are now but possibly offer this as a lighter version for racers etc or where something much lower profile is required. It could even go on the Diff end of the prop and attach to the two tapped holes on the underside of the diff-nose. The intention for this is mostly Jeep & Toyota - potentially big markets for the right product.

Any other potential problems you can foresee?

Si

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The problem with Aluminum is that it would overheat and melt when used as an emergency brake. Brakes need to be designed for very high temperatures.

Many a machine tool used to use them, as it avoids the potential issue of polluting the brake linings of other type systems with oil.

That said, they were problamatic and usually didnt work, but typically that was poor mechanism design (read cheap) than the principle, as when they were re-furbished, they work well.

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Re:One concern is that the two cones might rust together? Nick (Rogue Vogue) suggested making one half out of Aluminium and the other out of steel which is a common config for cone clutches as they tend not to rust together, nor bind. That of course means the outer Al bit can be Anodised! BLING!!!

Simon

You could also consider a Keronite ceramic coating for the alloy part on the inner part! http://www.keronite.com/

It is applied in a similar way to anodising but gives very high wear resistance and heat protection.

Williams Formula 1 use Keronite on their pistons to disperse heat and reduce weight by having lighter castings.

You may recall Tom (my son) spoke to you about Keronite at Billing last year. He works for them as an applications engineer. Give him a ring if you want to find out more.

John

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Cheers John - that might be just the ticket!

My experience of them on machine tools is that they have been pretty good. The one on my Myford is at least 40 years old - and perfect. As much as anything, that was the inspiration!

Overheating could be a problem when used as an emergency brake although the Al is a good conductor so the heat would not be concentrated as much as it is on a pad. If this Keronite stuff couls be applied to the Al, that might provide the answer!

Cheers,

Si

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Simon.

Steel and brass.

Well for those of you old enough to have use Ferode VG 95 competition brake linings. I can tell you that there was a lot more brass in the linings than Ferodo.

The old cone clutches were leather covered.

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Given the reading I used to do in Motor Sport magazine (when Bill Boddy was Editor, and DSJ wrote Letters from Europe) cone clutches were often used in early cars, and were often described as fierce or sudden. I formed the opinion that the mechanical advantage of the cone shape was used to compensate for the poor friction qualities of the lining materials they had available.

My personal experience of cone clutches was in Laycock overdrives, as fitted to MGBs. In those the clutch was engaged by hydraulic pressure from a plunger pump driven off the gearbox output shaft. Clutch release was effected by both opening the hydraulic circuit, thus dumping the pressere, and several coil springs (compressed as the clutch engaged) forcing the carrier for the inner lining away from the outer.

You may need to give similar encouragement for the handbrake linings to disengage.

The significant point with these overdrives is that the driver was encouraged to keep the power on when engaging overdrive, as the speed difference between the inner and outer tended to screw one into the other and give a very positive engagement. Here the cone was used to give an effective non-slip clutch in a small diemension. It may be that you need to ensure that at least one of the cone carriers has enough mechanical movement to allow it to be drawn into a tighter bond with it's mate as one cone rotates wrt the other.

I'm not certain on the ability of a cone handbrake to withstand mud and grit. You might benefit from scrolled slots (as in grooved brake discs) in one surface, to give a channel for the muck to drop into while on it's way out.

HTH

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I'mpleased tor ead your reply David. Those were the days.

I did enjoy bothBoddy and DSJ

I still have a load of Motor Sportdating from 1961 to 1990.

If this guy Hamilton carries on like he started I'll start taking an interest in F1 again

mike

I cancause trouble in an empty house !!!

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I have an idea for using a cone brake / clutch in place of a disk & caliper for a handbrake conversion.

Why? Well, it would be a lot smaller diameter (120mm instead of 230mm). This would be an advantage as I could make one for vehicles where the bottom of the transfer case is lower between the chassis rails.

I reckon it could be a bit lighter (7kg in place of 10kg for an X-Brake and 15kg for the drum).

I've come up with a design for a fully sealed expander mechanism which will push the cones together so it should survive mud & poo pretty well. Mud will get inbetween the cones, but it should centrifuge out as it does with a disk, just not as quickly.

Both cones would be made from steel without any additional friction material in between. Although this would allow the cones to wear, the amount of metal in contact should make them very long lasting.

There is a public perception that disks are better than drums (and they are), but I wondered what the perception of cones is? Particularly with the Superwinch EP series using cone brakes.

If you were looking at such a thing, what would your thoughts or concerns be?

TIA

Si

Si, Any chance of you designing a sealed multi plate wet parking brake for LandRovers? Perhaps you could adapt some bits from an auto transmission. It could be made compact and should address all the problems encountered with handbrakes on vehicles used in deep muddy conditions. Personally I have very few problems maintaining the standard series 2 handbrake, but if I did I would just fit an underdash push/pull parking brake ratchet handle from an early car to my service brake pedal.

The standard handbrake would still be there to satisfy MOT or competition regs.

Bill.

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A particular manufacturer of machines that we service use cone clutches with a steel inner cone and a ferodo lining on the outer. They are complete cr**

We serviced a rotavator that came in muddy, so we did what we always do and pressure washed it. Big mistake as a week or so later the steel rusts and literally bonds itself to the ferodo, not only could you not disengage it but trying to bent the release arm!

Other grass cutting machines from the same manufacturer are always burning out clutches and destroying thrust bearings.

I think the automotive industry gave up on them for good reason.

Stick to the disk Simon, it's the muts.

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