Cornflaker apparatus...
Dave,
You’ve asked an interesting question. Reviewing the relevant publication helps to an extent, but doesn’t definitively answer the question.
2007-0125907 is the publication number of US Patent Application No. 11/292,556, since issued and now US Patent No. 7,434,764 (the ‘764 patent).
To understand the ‘black box’ 18’ referred therein you can look to the patent application incorporated by reference. More specifically, the specification of US 7,434,764 describes 18’ as a translational thrust system and incorporates by reference US Patent Application No. 11/140,762. This application, published as US 2006-0266883 and now US Patent No. 7,413,142 (the ‘142 patent), describes a translational thrust system where a transmission shaft 46 drives a spur gear 84, preferably a sun gear, located between a multitude of planet idler gears 86, and spur gear 88 with inwardly [toward axis of rotation of tail rotor drive shaft] facing gears, thereby driving the translational thrust system 30. See the ‘764 patent at paragraph [0035], Fig. 2, and Fig. 3.
The transmission described in the ‘142 patent is fixed ratio; Fig. 3 describes an embodiment with engine, main rotor, and tail rotor rpm’s of 2100, 320, and 2140 respectively. The innovation here seems to be the counter- rotating main rotor blades and tail rotor system.
The ‘764 patent, in contrast, describes a rotary wing aircraft where the innovation includes counter-rotating main rotor blades having variable velocities with respect to the tail rotor speed, albeit through a very different transmission.
Comparing claim 1 of the '764 patent as filed to the allowed claim 1, and reading paragraph [0026] while looking at Fig.2, it appears that the variable speed functionality is effected in the main gear box rather than the black box out on the tail boom. Regrettably, there is very little additional disclosure about the specific means - the variable speed systems 30A and 30B – beyond their placement on the main rotor drive and being downstream from the tail drive.
I wonder whether the X2 transmission more closely resembles an embodiment disclosed in the ‘142 patent rather than one of the embodiments disclosed in ‘764 patent. As the ‘142 patent includes counter rotating main rotor blades and a pusher system, whereas the ‘764 includes counter rotating main rotor blades, a pusher, and a means to decouple their respective speeds, I would guess the X2 in its present form to more closely resemble one of the less ambitious embodiments of the ‘142 patent.
On an unrelated note, review of the prosecution of the ‘764 patent illustrates how claims can get narrowed during prosecution - a subject discussed previously in the context of the electric motor driven transmission Sikorsky patent application now before the PTO. Notable and applicable here is that the ultimately allowed claim 1 is much narrower, and I believe much clearer, than the originally filed claim.
Cheers!
As-filed claim 1:
A main gearbox of a rotary-wing aircraft comprising:
a gear box;
a tail rotor system driven by said gearbox; and
a variable speed system driven by said gearbox downstream of said tail rotor system.
Allowed claim 1:
A main gearbox system for a rotary-wing aircraft which drives a main rotor assembly and a tail rotor system comprising:
a main gear coaxial with a main rotor shaft of the main rotor assembly;
an input shaft driven at engine speed;
a tail-take-off shaft driven by said input shaft, said tail-take-off shaft driven about a tail-take-off shaft axis of rotation;
a reduction stage shaft driven through said tail-take-off shaft to drive said main gear, said reduction stage shaft driven about a reduction stage shaft axis of rotation which extends across at least a portion of said main gear;
a variable speed system upstream of said reduction stage shaft and downstream of said tail-take-off shaft, said variable speed system operable to drive said main gear speed at a variable speed relative to the engine speed; and
a tail rotor system driven through said tail take-off shaft, said tail rotor system driven at a constant speed relative to the engine speed.
Last edited by NonSAC; 28th Feb 2010 at 18:30.