The wing design developed by Curtiss was substantially different than that of the Wright Brothers. While the Wrights used wing “warping” to control rolling and banking, Curtiss used ailerons, which are now standard throughout the aviation industry. Nonetheless, the federal courts “protected” the Wright Brothers against competition from a device they did not invent!
No, this case illustrates precisely what inventors are up against.
Here is claim 1 of the Wright patent:
- In a flying-machine, a normally flat aeroplane (a wing) having lateral marginal portions capable of movement to different positions above or blow the normal plane of the body of the aeroplane (the wing), such movement being about an axis transverse to the line of flight, whereby said lateral marginal portions may be moved to different angles relatively to the normal plane of the body of the aeroplane, so as to present to the atmosphere different angles of incidence, and means for so moving said lateral marginal portions, substantially as described.
What the Wrights had invented was the concept of using a variable-incidence surface to provide for roll control, said control proving to be crucial to the feasibility of a flying machine.
Curtis saw the brilliance of this and tried to get around the patent by having small, movable sections of the wing – ailerons – that could that could be moved without “warping” the whole wing. But the patent clearly covers this; ailerons are in fact “lateral, marginal portions” of the wings. The patent was written this way because the Wright’s had already envisioned other ways of implementing the principle of a variable-incidence surface. The term “wing warping” does not appear in the patent.
When the courts ruled against Curtis, he responded by putting his movable surfaces between the wings (his plane was a biplane like the Wrights). Since the movable surfaces in the Wright patent are described as being part of the wing, Curtis claimed this put his machine outside the scope of the Wright’s patent.
This is typical. The Wrights developed the concept of achieving roll control through a variable-incidence, moveable surface. Curtis seizes on this concept and makes a minor change so that he can make us of the Wright’s development.
Fortunately, for inventors, patent law recognizes the Doctrine of Equivalence. This Doctrine states that if a subsequent device achieves the same benefit in “substantially the same way” as the patented device, it is an infringement even if it differs in some details.
Of course, determining what constitutes “substantially the same way” is a matter of judgment and leads to many arguments. In the case of Curtis, he had been trying to build a flying machine for years. The fact that he came out with his ailerons and then his between-the-wings moveable surface only after the Wright Flyer was unveiled made it clear that he had copied, not created. The Wright’s patent was, properly, upheld.