Tennant Case 7: Anderson's Black Rock, Inc. v. Pavement Co. (1969)

This case discusses the patent of a system of laying down a seamless layer of asphalt. Typically, asphalt is laid down in strips; by the time adjacent strips are laid down, the previous strip has cooled and the strips don't bond as well as they should. Pavement Co. tried to address this problem by building a chassis which heats, lays down, and smooths asphalt at these "cold joints." The question of patentability arises from the question of whether combining the spreader and the radiator results in an invention.

The addition of the heater on the side of the vehicle is the main point of contention. The owner of the patent claims that previous heaters were used primarily for patchwork, whereas this heater is to be used for continuous heating of the previous strip so as to prevent cold joints. The District Court found that the new design was not an invention, citing that the chassis was merely a combination of prior art. The Court of Appeals ruled that it was, in fact, an invention. The Supreme Court reversed this ruling, citing that the patent was invalid due to the fact that it was "obvious."