# Bicycle Mechanics - Invert a bike brake

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View Full Version : Invert a bike brake

Jlane
08-02-08, 08:22 PM
As an inventor (see signature, biography, and visit my site www.smartbuttonshoes.com) I am working on a project that will require me to have an inverted bike brake:
More specifically: I am basically building a puppet (dummy) (of a fish) whose mouth (and eyes) must be controlled by a bike brake lever (and its mechanisam) becuase the puppets will be used on stage and the preformers will be visible. They need to be able to control the basic functions (eyes and mouth) with the lever and then be able to exaggerate and act normally with their other free hand. The brake need to be oppsite a normal brake as in the brack should be closed and then when the lever is squeezed the mouth will open. When you let go of the lever the brake should then revert back to its closed stage.

If you know how this can be done or if you have any ideas, please post asnd/or email me. If you could draw a picture and email it, that would be even better!

Thanks

joejack951
08-02-08, 08:40 PM
While what you are proposing isn't possible using just a brake caliper, it should be easily achieved using some pieces added onto the caliper. Make angle extensions from the caliper arms that are just crossing each other when the caliper arms are furthest apart. Now, when you close the caliper, the extensions will move further past each other. Basically, imagine a "V' with the point of the "V" being the caliper pivot and the ends of the "V" being where the brake pads would mount. Now make that "V" a diamond shape like this "<>" (sorta). The second "V" is the extensions though I'm not really showing how they would cross :) Hopefully you get my point.

DeadSailor
08-02-08, 09:22 PM
youd probably have an easier time going to a hobby shop and buyin whatever those kits are called that let you build small scale working models of machines. like the ones that have rods and hinges....springs...pulleys...stuff like that

the easiest way i can think of doing it...would probably end up weakening the brake

eddy m
08-03-08, 09:46 AM
That's actually an easy design problem, but building it from commonly available parts requires a little ingenuity.
Get an ordinary lever like the kind used on flat bar bikes. A small BMX lever would work fine. Mount the lever on a dowel, mount a cable housing anchor on the lever, run the cable through the cable stop and anchor it to the far side of the dowel. Cut away everything that gets in the way. When you squeeze the lever, the cable housing follows it back toward the far end moving the cable out through the housing. It's harder for me to describe than to visualize, but sadly I have no graphics capability.
The other thing that would work is if you took the lever and reversed it in the body. That might be easy to do with some levers, but you would need to hold it open or rig some kind of spring to hold it open.
When you squeeze the lever, it will open the caliper.