A utility patentdesign patent protects the physical appearance of an invention and is purely cosmetic in nature. A design patent does not cover the parts of the invention which carry out a certain task. For an original invention, it may be beneficial to an inventor to obtain both a utility patent and a design patent for one article because parts of an invention may possess both a functional and an ornamental purpose. In this instance, legally distinguishing a utility and design part of an article is not done easily.
An ornamental design patent may include an entire aspect of an article, though it is possible to file a design patent which only covers a certain part of an article. When a design patent applies to a surface ornamentation, the design must be shown applied to the article through detailed drawings. The article should be distinguished from the proposed patented design through the use of broken lines because it does not embody the design itself. Drawings are essential for design patents and should be detailed and accurate to portray the actual design of the article.
A design patent application filed to the USPTO should only have a single claim on a design. Two distinct and separate designs in one application are not allowed according to 37 CFR 1.153. Two independent designs which are not supported by or related to each other should be filed in separate claims to the USPTO. Separate claims should also be filed if two related designs are distinct enough from each other, in terms of shape and appearance.
Modified designs, however, are allowed to be filed and consolidated into one design patent application. These modified designs are embodiments of a single design and should have very few configuration differences from each other.