Section 101 Examples
Example 32: Paper-Making Machine

This is an example provided by the U.S. Patent and Trademark Office for analyzing Section 101 patent subject matter eligibility issues. In particular, this example was created to help explain the 2014 Interim Guidance on Patent Subject Matter Eligibility. The original PDF document is found here.

This example should be viewed in light of the introduction that was provided with it.

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Example 32: Paper-Making Machine

This hypothetical example demonstrates the use of the streamlined analysis. The claim below is based on the technology from U.S. Patent 845,224, which was upheld by the Supreme Court in Eibel Process Co. v. Minnesota & Ontario Paper Co., 261 U.S. 45 (1923). As a streamlined analysis would not result in a written rejection, the discussion sets forth exemplary reasoning an examiner might use in drawing a conclusion of eligibility.


Fourdrinier machines are used to make paper from a slurry of wood pulp mixed with water (called “stock”). The paper-forming section of the machines typically comprises a headbox that feeds the stock onto one end of a conveyor belt called a “paper-making wire”, which is passed over a series of rolls at a constant speed. The belt carries the stock from the headbox end of the machine (called the “breast-roll end”) to the other end (called the “couch-roll end”), while simultaneously draining and shaking the stock to form a continuous paper web. The paper web is then passed into the press section of the machine for further processing.

At the time applicant made the invention and filed the application, it was routine and conventional to arrange the paper-making wire so that the breast-roll end was at the same or a lower height than the couch-roll end, and to feed the stock from the headbox onto the paper-making wire at a speed substantially slower than the wire speed. However, this arrangement necessitated running the machine at an overall slow speed (less than 500 feet/minute) in order to avoid undesirable effects (e.g., waves, wrinkles and ripples) on the quality of the paper web.

Applicant’s invention is a Fourdrinier machine that solves the problem of running the process at a slow speed by raising the breast-roll end of the paper-making wire to a height substantially above the couch-roll end, and by using gravity to feed the stock into the machine at a speed approximately equal to the wire speed. This gravity-fed arrangement permits applicant’s machine to be run at an overall speed that is much higher (e.g., more than 700 feet/minute) than conventional machines, without producing undesirable effects on the quality of the paper web.

Hypothetical Claim

1. A Fourdrinier machine having a breast-roll end of a paper-making wire maintained at a substantial elevation above level, whereby stock is caused to travel by gravity, rapidly, in the direction of movement of the paper-making wire, and at a speed approximately equal to the speed of the paper-making wire.


Claim 1: Eligible.

The claim recites a Fourdrinier machine with a paper-making wire (conveyor belt) that is passed over a breast-roll. The claim is directed to a machine (a combination of mechanical parts), which is one of the statutory categories of invention (Step 1: YES).

Next, the claim must be evaluated to determine if the claim is directed to a judicial exception. But when the claim is reviewed, it is immediately evident that although the claimed machine operates using gravity, which is a law of nature, the claim clearly does not seek to tie up this law of nature so that others cannot utilize it. In particular, the claim’s recitation of a Fourdrinier machine (which is understood in the art to have a specific structure comprising a headbox, a paper-making wire, and a series of rolls) that is arranged in a particular way to optimize the speed of the machine while maintaining quality of the formed paper web makes it clear that the claim as a whole would clearly amount to significantly more than any recited exception. The claim as a whole adds meaningful limitations to the use of the law of nature (gravity). Additionally, use of the law of nature improves paper-making technology. Thus, eligibility of the claim is self-evident for these reasons, and there is no need to perform the full eligibility analysis (e.g., Steps 2A and 2B). The claim is patent eligible.

If the examiner believes that the record would benefit from clarification, remarks could be added to an Office action or reasons for allowance indicating that while the claim recites gravity - a law of nature - the claim clearly amounts to significantly more than the mere use of gravity by providing meaningful limitations to the law of nature and additionally improving paper-making technology.

It is noted that although Eibel Process Co. was decided prior to the 1952 Patent Act, the Supreme Court has subsequently described the decision as upholding the eligibility of process claims containing a law of nature. See, e.g., Diamond v. Diehr, 450 U.S. 175, 187-88 (1981); Parker v. Flook, 437 U.S. 584, 590-91 and n.12 (1978).