[python] Re: hands free braking aka coaster brake component
- From: Darin Wick <darwin.enderson@xxxxxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Mon, 9 Apr 2012 22:07:27 -0700
I can't find what I'm thinking of now, but not long ago I saw a photo or
diagram of a backpedal brake that is activated by a ratcheting mechanism on
either the chain or the chainring. Some sort of arm that would ratchet
along when pedaling forward, but would engage with the chain/chainring when
backpedaling and pull on a cable, which could then actuate any sort of
brake - rim, disc, or drum - though this was a particularly old bike and it
looked like it was using something similar to old rod brakes. It's
ultimately a variant on what Mike describes in his first post with the
extra freewheel.
A search of the patent database reveals a number of patents that are based
on that concept:
http://www.google.com/patents/US4134481?printsec=drawing&dq=back+pedal+brake&ei=Rb2DT_KPEeSyiQLm1r3fBQ#v=onepage&q=back%20pedal%20brake&f=false
http://www.google.com/patents?id=IH8jAAAAEBAJ&pg=PA7&dq=back+pedal+brake&hl=en&sa=X&ei=Rb2DT_KPEeSyiQLm1r3fBQ&ved=0CD8Q6AEwAw#v=onepage&q=back%20pedal%20brake&f=false
http://www.google.com/patents?id=s9B1AAAAEBAJ&pg=PA5&dq=back+pedal+brake&hl=en&sa=X&ei=F76DT4rxFqvciQKcounABQ&ved=0CEwQ6AEwCTgK#v=onepage&q=back%20pedal%20brake&f=false
It would be a fun fabrication project!
If over-tensioning the cable is a problem, something like the
"self-energizing cantilevers" listed at
http://www.blackbirdsf.org/brake_obscura/mtb.html could be a good solution,
if you can find a set. Or just use a rod instead of the cable, since
presumably the brake will always be in the same position relative to the
crank.
On Mon, Apr 9, 2012 at 6:59 PM, Paul Cartwright
<paulcartwrightx@xxxxxxxxx>wrote:
> Mike,
> I like your idea. Also nice because now the back-pedaling coaster brake
> can be attached to a front wheel brake which is more effective at stopping
> the bike. The only problem I foresee is that it would be easy to break
> the cable with too much force applied to the brake.
> Perhaps spring-loading the cable so that a firm pressure may be applied
> after which the back pedaling motion hits a stop.
> Paul
>
>
> On Sun, Apr 8, 2012 at 7:53 PM, Mike Power <mpower.lists@xxxxxxxxxxxx>wrote:
>
>> I really like the idea of hands free braking. But I do not like the idea
>> of being constricted to the components that support it. As the only
>> components that support it are hubs, and I do not find coaster brake hubs
>> to have all the features I am looking for.
>>
>> One thought I had was to engage a more traditional brake system (disc
>> brakes, rim brakes) with a reverse in the drive system. Unless you are
>> doing a fixie (in which case you don't want a coaster brake anyway) then
>> reverse pedaling is an unused dimension of the bicycle. Not pedaling at
>> all, and reverse pedaling are no different when it comes to the physical
>> dynamics of the bicycle.
>>
>> One concept would be to install a free wheel to the left side of the
>> crank. Put a cable or loop of cable on the free wheel and mate the cable
>> to some sort of brake. When you are pedaling forward the crank should be
>> engaging the drive train and the brake freewheel should be slipping. When
>> you are pedaling backward the crank should be engaging the brake system and
>> the drive freewheel should be slipping.
>>
>> Thoughts? Does something like this already exist?
>>
>> Mike Power
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