[python] Re: News from Brazil

Hi Olaf! See the drawing below:




The red drawing, is the rear frame. You may see that there are two 6 mm thick 
plates welded to the 40 x 40 mm square rear tube. These two plates are the 
"arms" which holds 12 mm dia. bolt (green). These plates performs the same task 
as the two cranks used in the original Jürgen's design. The cyan part, is the 
bearing shell + the front frame. The bearing shell is a 40 mm O.D. / 26 mm I.D. 
tube. The bearing shell is made in a lathe with two 32 mm dia. cuttings to set 
the bearings. The magenta parts are washers.

The bearings used, are two 7201 B, i.e. angular contact ball bearings (see 
below)


This bearing isn't an usual type of ball bearing. The races of the balls are 
angular (similar to the tappered roller bearings). It is the same function of 
the ball + cup conventional (threaded) headsets, but in a single cartridge 
unit. The angular contact ball bearings, may be pre-loaded to asure a perfect 
work. This pre-loading is obtained by fastening the nut of the bolt-pivot.

The two arm-plates are almost rigid then we must assemble the steering with the 
washers to asure a zero gap between the plates and the bearings. About one 
quarter turn of the nut is enough to pre-load the bearings.

[]'s Eduardo

Ypê Bike: http://www.ypebike.cjb.net/
Ypê Mono: http://www.ype.unicyclist.com/




----- Original Message ----- 
From: "olaf" <noll@xxxxxxxxx>
To: <python@xxxxxxxxxxxxx>
Sent: Wednesday, April 14, 2004 8:24 AM
Subject: [python] Re: News from Brazil


> 
> This looks veeery nice Eduardo!
> 
> Could you make a rough sketch on the steering head design?
> 
> 
> 
> olaf


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