 In the Graham case, the '798 patent was originally rejected by the patent examiner as being insufficiently distinguished from the previous '811 patent.The only two claims which differed between the two patents were (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.One argument which Graham raised before the court, but had not raised before the USPTO, was that in the new '798 design, the flexing of the plow shank was limited to the points between the spring clamp and the tip of the plow shank, absorbing the shock of hard objects on the ground more efficiently.