Legal Definitions - open-ended claim

An open-ended claim in patent law refers to a type of claim that uses specific transitional words, most commonly "comprising" or "including," to introduce the elements or steps of an invention. These words signal that the invention may include additional components, ingredients, or steps beyond those explicitly listed in the claim, without narrowing the scope of protection. This approach provides broader coverage for the patent holder, making it more difficult for others to circumvent the patent by simply adding minor features or steps to the invention.

Here are some examples to illustrate an open-ended claim:

• Example 1: Mechanical Device

  Imagine a patent for a novel type of bicycle chain. An open-ended claim might read: "A bicycle chain comprising a plurality of inner links, a plurality of outer links, and a plurality of pins connecting said inner and outer links."

  How it illustrates the term: This claim protects a bicycle chain with these three fundamental components. Because it uses "comprising," the patent would also cover a chain that includes these three parts plus additional features, such as a specialized coating for rust prevention, integrated sensors for wear detection, or unique lubrication channels. The patent is not limited only to chains with *exactly* those three parts and nothing else.

• Example 2: Chemical Composition

  Consider a patent for a new formula for a household adhesive. An open-ended claim could state: "An adhesive composition including a polymer resin, a solvent, and a tackifier."

  How it illustrates the term: This claim protects an adhesive containing these three essential ingredients. Due to the word "including," the patent would also cover an adhesive that incorporates these ingredients *and* additional components, such as a UV stabilizer, a colorant, a fragrance, or a flame retardant. The patent cannot be easily avoided by simply adding an extra ingredient to the core formula.

• Example 3: Software System

  Suppose a patent is granted for a new online project management system. An open-ended claim might be: "A project management system comprising a task assignment module, a progress tracking module, and a user notification module."

  How it illustrates the term: This claim describes a system with these three core functionalities. The use of "comprising" means that the patent would also cover a system that incorporates these modules *and* additional features, such as a budgeting module, a document sharing module, or an integration with third-party calendar applications. The patent protects the fundamental system even if new functionalities are added later.