Cable operated Spot Caliper

[MSPV12]

Hi folks, wonder if anyone here can help me with a physics question?

I have a pair of cable operated spot calipers that I intend to use as my parking brake. Rather than using a traditional hand brake lever, I want to have a linear motor to operate the brake. So my question is, how much force is usually applied by a typical manual lever and therefore what max load rating would the motor need to have to operate the parking brake effectively?

I have found an nice unit that is rated at 200lbs max force. Hopefully this is adequate, but I am only guessing.

Thanks in advance.

Mark

[swampy56]

Have you checked if it will pass an MOT with that? Just a thought.

[MSPV12]

I hope so.

My car is intended for the track 90% but I still hope to be able to drive it on the roads once in a while. Otherwise I wouldn't even bother with a hand brake.

Many cars today, new Jags, Range Rovers, VW Passats & Audi A6's and various French cars etc, all use a similar system, which gave me the original idea. So long as the pressure is applied constantly and cannot be released through power failure, it should be fine and qualify as a "mechanical operation". Unlike a line-lock type of hydraulic lock, which loses pressure over time and obviously would not meet MOT requirements.

Happy to hear any input or further thoughts though, so thanks for your reply.

Here's what I am thinking of using, (or something similar)....

http://cgi.ebay.co.uk/12-Linear-Actuator-200lb-Adj...

Edited by MSPV12 on Friday 13th August 19:14

[MarkWebb]

drove a citroen piccasso (I think) in France the other day. It comes with a electric motor driven handbrake as std

[Steve_D]

The method can comply with IVA if the brake is maintained in the on position by mechanical means. So a gearbox or screw thread actuation will work.
The manual goes on to say the switch must be protected from inadvertent use. It must also only be possible to release the brake with ignition on but the brake can be applied without the ignition on.

Steve

[k wright]

Not trying to be a stick in the mud but you should spend your time elsewhere on the car and just use the factory setup. If you ever autocross the car (never say never) the hand brake handle will be very useful.

[MSPV12]

I understand your point K, and that may be well worth the consideration of many Ultima builders. In my case however, I am not building an Ultima.

I visit your excellent section of these forums as the knowledge base is top notch and my car is not dis-similar in many ways, although it is a replica of a 60's Le Mans race car, where I am attempting to keep things (at least on the surface) in keeping with the original car. I.e, no handbrake lever.

I will be racing the car when she's finished, but will not be doing any autotest type of driving, so don't foresee the need to use the handbrake other than for parking it up and passing an MOT.

Despite my plans to race the car, I cannot commit to not driving it occasionally on the road, just for laughs once in a while! But with the fully rose-jointed suspension, severely stiff spring rates and a very low ride-height, that wouln't be very pleasant except on the very smoothest of highways.