[python] Re: Foldable python
- From: Tihamer Juhasz <balamber@xxxxxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Thu, 11 Apr 2013 06:45:13 +0300
Hi Martin and Jürgen,
After seeing the clever tie rod pivot in earlier posts I was thinking too
of including a folding mechanism using two sets of these pivots: the
regular/first pivot at say 65 degrees from the horizontal plane, the
second/folding pivot beneath/after the seat at 115 degrees (180-65, so it
mirrors the first pivot on the vertical axis), and have some mechanism to
block this second pivot while riding the bike. The two pivots turn 90
degrees each to give a complete 180 fold. If they are arranged at mirrored
angles, they can be used to fold the bike.
Considerations: - have both pivots before the seat support on the frame to
ensure that the seat stays together with the back wheel or remove the seat
when folded.
- place the pivots so that the two folded sections are of the same length,
to ensure that the bike can be pulled around on the two wheels like a
wheeled bag, just as Jürgen suggested.
- when using the folding mechanism as seen on your drawing and on folding
bikes, there is no need for using the steering pivot for folding. Just
place it in the middle of the wheelbase and you have a wheeled bag-bike.
The problem with this folding mechanism is finding or making one. I don't
think you can find it as a separate part, so need to cut it out of a
folding bike, which is a pretty expensive affair.
After going through all the above, and considering weight, simplicity and
function I think that best is to have only the regular/steering pivot and
make it separable, so there is no need to have a second pivot/folding
mechanism. Just split the bike in two and attach the two parts next to each
other with some plastic pipe clips (2 clips opposite to each other, see for
example here:
http://www.wickes.co.uk/plastic-pipe-clips-22mm-pk50/invt/421621/). I used
these clips on my SWB recumbent for other reason and they are pretty sturdy.
Hope to show pictures of my finished bike soon.
Regards, Tiha
On Wed, Apr 10, 2013 at 11:27 PM, Jürgen Mages <jmages@xxxxxx> wrote:
> Hi Martin,
>
> your idea should work if you manage to give the back of the seat enough
> support. A clever solution would enable the ability to push the folded bike
> around on its wheels, so you don't have to carry it.
>
> Cheers,
> Jürgen.
>
>
> On 10.04.2013 19:10, martin noring wrote:
>
>> Hi everyone!
>>
>> After getting inspired by Vi's foldables and after borrowing a Bromton
>> from
>> a friend to be able to travel by bike and train in Sweden (which is
>> illegal
>> with a regular, unfoldable bike), I've of course started thinking about
>> pythons and foldables. What if I made a python, with a closable pivot
>> (like
>> the ones on a Bromton) on the main tube between the seat and the back
>> wheel, it could be made fairly small. If I then made a seat of a fork and
>> belts, like the one on Jürgen's pythons, I guess I could shrink it into a
>> really practical size. I've made drawings. Any ideas and comments?
>>
>> Regads,
>>
>> Martin
>>
>>
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