Case 30: Vas-Cath Inc. v. Mahurkar (1991)

In this CAFC case, Mahurkar filed a design application for a double-lumen catheter. He also submitted for a Canadian Industrial Design using the same images and some additional text as his original patent application. In October 1984, Mahurkar filed for the first of two utility application using the same drawings as before, and the second utility application soon followed as a continuation of the first. Vas-Cath sued Mahurkar claiming that its products did not infringe on Mahurkar's design. They claimed that the utility patents Mahurkar secured relied on images only, and there was insufficent verbal description of the product.

This case concerns the requirement of "written description" and what satisfies this requirement. This language stems from early patent laws which require written descriptions for two reasons: (1) to allow others to create the invention themselves and understand how it works, and (2) to put into common knowledge all the aspects of the invention to help determine if any part of the invention was previously known and thus unpatentable. The CAFC determined from prior rulings that drawings do satisfy the written description requirement and that the question the District Court asked concerning what exactly was the invention is moot. Claims don't cover single aspects of an invention, but rather the entire combination of features in concert within the invention. The CAFC held that the summary judgment granted was invalid because the design patent stands, and the case was remanded for further consideration.