Monday, October 10, 2011

Once More into the Depths of the US Patent Office

I have been trying to remind myself to take photographs of bits and pieces as I go along; more for my own records as for any other purpose.  I have been diligently sanding, filing and reworking the rear hub I will be using.  The brake plate is about ready to have the holes drilled and threaded to take the screws for the frame and screen for the hot air exhaust port.  I’m happy with how it has turned out.  So I turned my attention to the brake lever.  It was chromed from the factory but the quality of the metal work on the arm was atrocious.  This really surprised me, because Honda has always been lauded for the quality of their products.  There must be something besides motorcycles which has earned Honda the reputation for quality.

While not bending over the work bench with jewelers files in hand and aluminum oxide paper at my elbow I once more went into the breach.  Well not really just the patent archives. 

                                                       Inventor James R. Birmingham

What I found was a very keep it simple patent for several major improvements on the POSA carb.  Can’t decipher if this is a complete new design or just a major modification.  However what was interesting was that the description for the drawings and explanation of how the carb works was very easy to follow.  Unlike some patents I have attempted to read.  I do think I found one thing the inventor didn’t think of or include in the drawings.  There is a screw, labeled 30, which holds the fuel tube in place.  Fuel tube being 27 and the screw fits into groove 29.  The problem is that he neither describes nor shows how the throttle body 31 is supposed to move past screw 30.  In the drawing the throttle body is in the closed position.  In the open position 31 will move to the right in drawing FIG. 9.  The left hand extreme edge of the throttle body is defined by a line which abuts screw 49.

I may just be dense but I think that is a problem and I have read the patent several times.  I think there is a way to fix that over site but not really sure.  I would mill a slot in the face of throttle body 31 and relocate screw 30 closer to the throat of the carb.  Screw 30 would be part of a lying on it’s back L shaped lug which would support the fuel tube but also allow the throttle body to move past it.  The lug would fill what would otherwise be a vacuum leak in the throat of the carb if the slot for the screw 30 was left open.

But until I get my hands on a real POSA or build a copy of this carb I won’t know if I’m right or not.  So anybody got a POSA Fuel carb to lend me? 

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