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Old 2nd Mar 2010, 20:43
  #588 (permalink)  
Dave_Jackson
 
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NonSAC

Unfortunately, my posting #642 was not very clear. In addition to mentioning the blank box [item 18'] to the propulsor it should have also mentioned the blank cylinder [item 110] to the rotors.

Both of these blank enclosures represent the undefined variable-speed units.

IMHO, this requirement to drive a pair of main rotors and a propulsor, while simultaneously providing variable speed to the rotors and propulsor, present an extremely difficult challenge for the power-transmission section of any engineering department.


However having said that; the title of application 20070125907 and subsequent patent 7,434,764 says;
"Variable speed gearbox with an independently variable speed tail rotor system for a rotary wing aircraft."

Please correct me if I am wrong, but it appears to me that Sikorsky can patent their 'gear-trains', as shown, but in no way can they consider this as patenting anything related to the design of variable speed mechanisms. This being the case, why does the phrase "variable speed" have such prominence in the title of their patent? Why does the phrase "variable speed" appear 25 times within the patent.

________________________

Thank you for the side note related to the narrowing of claims during prosecution.
Interestingly, the above patent 7,434,764 has a divisional application patent 7,651,050, dated January 26, 2010.


Thanks for your much-appreciated explanations.

Dave


Edit: 1/ Bold - by me. 2/ Clarified.

Last edited by Dave_Jackson; 3rd Mar 2010 at 19:03.
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