Obviousness and Non-Obviousness (JWB)
U.S. Patent No. 2,627,798 (hereby referred to as the '798 patent) relates to a spring clamp which permits plow shanks to be pushed upward when they hit obstructions. The controversy centers around a hinge by which the shank of the plow rotates when it encounters an obstruction.
Before the '798, Graham patented U.S. Patent No. 2,493,811 (hereby referred to as the '811 patent), and the '798 cited the '811 patent. The only differences found between the two patents are the following: (1) the stirrup and the bolted connection of the shank to the hinge plate do not appear in '811; and (2) the position of the shank is reversed, being placed in patent '811 above the hinge plate, sandwiched between it and the upper plate. Instead, in '798, the shank is held in place by the spring rod which is hooked against the bottom of the hinge plate passing through a slot in the shank.
Argument for Valid Patent
The '811 patent had several flaws. The shank was not rigidly fixed to the hinge plate and was therefore allowed to wobble and fishtail. Additionally, with the shank directly below the upper plate, wear could occur on the fragile (and expensive) upper plate.
To remedy these problems, the '798 patent moved the shank below the hinge plate to reduce the problem of wear on the upper plate. Additionally, Graham added a bolt to keep the upper face of the shank into constant contact with the under face of the hinge plate to further reduce wear and to add stability to the shank.
The problems with Graham's original '811 patent were enough that he did not fix them before submitting the application for the '811 patent. If the problems had obvious solutions, Graham would have fixed the problems on the '811. It took four and half years to submit a new design fixing said problems, and therefore they were not obvious solutions.
Argument for Invalid Patent
35 U.S.C. 103 states that a patent will not be valid if
"the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains."
Therefore, if the changes made in the '798 patent were obvious to a mechanic of ordinary skill in the field, then the patent is invalid. The petitioners argue that free-flexing of the shank is the crucial difference between the '798 patent and the prior art, the '811 patent. If this is the case, it should have been obvious to a mechanic of ordinary skill that boxing the shank in between the upper and lower plate would not be the best way to achieve a free-flexing shank. Such a constrictive set up would result in a limited range of motion. Switching the hinge plate and the shank appears to be the obvious solution to offer a free-flexing shank, and therefore does not meet the nonobvious conditions put for in 35 U.S.C. 103.
Bolting the shank to the hinge plate is the other difference between the '811 and '798 patents. With the first difference between the subject matter and prior art (the switching of the hinge plate and the shank) found to be obvious above, this bolting is the only difference that could make the '798 patent non-obvious. The technique used in this bolting was patented by Pfeifer in 1935 (U.S. Patent No. 2014451). Therefore, the '798 patent is merely a combination of the Pfeifer patent and the '811 Graham patent. Because this combination does not offer any new function or utility, it is an obvious combination.
Neither switching the shank and hinge plate nor bolting the shank to the hinge plate offer nonobvious changes from the prior art, thereby making the '798 an invalid patent.