Quality Claims
Home Your Host


What is a Patent?
Patenting Process
Quality Claims
Claiming an Invention
For Want of a Nail

A patent is frequently deficient in the quality of its claims, and the inventor is thereby denied the degree of protection of his invention to which he was entitled. The patent attorney who constructed the claims is, of course, the person responsible for the claims not being of the highest quality.

It would appear at first blush that any patent attorney would be able to construct a set of quality claims if the patent attorney were familiar with the subject matter of the invention. This view results from an underestimation of the difficulty of constructing quality claims—claims that only exclude prior-art products and services. The difficulty of claim construction is best illustrated with an example.

For the purposes of our hypothetical, pretend that "fasteners" for fastening two boards together are unknown. Imagine an inventor coming to "Typical Patent Attorney" (TPA) and showing an embodiment of his latest invention which he calls a "nail". TPA looks at the prototype and sees a rectangular elongated body with one end terminating in a head and the other end tapering to a point. The inventor asks TPA to prepare a patent application and TPA produces the following claim for the inventor's approval:

TPA's Claim - A device for fastening two boards together comprising an elongated body having a rectangular cross section and two ends, one end of the body tapering to a point, the other end of the body terminating in a head.

The inventor is quite pleased with the claim since it exactly describes his embodiment. TPA files a patent application with this claim. The examiner assigned by the patent office is unable to find prior art describing either the embodiment or fasteners of any kind and passes the patent application to issue.

TPA is pleased to be able to report to his superior that he completed the application with a minimal expenditure of his time. The inventor was pleased that TPA had so expeditiously obtained his patent for him. The examiner was pleased at having gotten rid of an application from his workload with so little risk of having the issued patent being ruled invalid at some future time for having been anticipated by the prior art. Apparently a pleasing result was obtained for everyone concerned.

After several years successful selling his nails, the inventor was faced with competition from an entrepreneur selling cylindrical nails. The inventor consults TPA about suing the entrepreneur for patent infringement. TPA informs the inventor that his patent does not cover cylindrical nails, and consequently the entrepreneur is not infringing the inventor's patent. In response to the inventor's look of incredulity, TPA consults the patent file and points to the inventor's invention disclosure: "See? You only disclosed a nail with a rectangular cross section. You didn't say anything about a cylindrical nail."

A messy but not unusual situation.

Now suppose the inventor had come to "Less Typical Patent Attorney" (LTPA) instead. LTPA, being curious and interested in demonstrating his ability to understand technology, asks the inventor how the prototype nail works. The inventor explains that when the nail is driven into two stacked boards, any attempt to pull the boards apart is resisted by frictional forces between the nail and the boards.

LTPA sees two options for claiming the invention. The first option is to claim the structure just as TPA did. The second option (and LPTA's preferred approach) is to claim the invention functionally as well as structurally:

LTPA's Claim - A device comprising an elongated body for fastening two overlapping boards together, the surface of the body exerting frictional forces on the two boards in opposition to any forces tending to pull the two boards apart after the device is inserted in the two overlapping boards.

The reason for LTPA's preferring this claim over the purely structural version is the general proposition that a function performed by one structure can often be performed by other structures. This claim illustrates the proposition by including in its coverage not only nails with rectangular cross sections but also nails of any other cross-sectional shape including cylindrical nails. The entreprenuer of the previous example would no longer be able to escape a lawsuit with LTPA's claim.

LPTA's claim is a great improvement over TPA's claim. LTPA is to be congratulated for taking a step toward the creation of a quality claim. However, LTPA's claim is only a modest step insofar as the quality spectrum of claims is concerned.

Let us now assume that our inventor had the good fortune of obtaining the services of "Rare Patent Attorney" (RPA) who benefited more from his technical training before departing for the field of law. RPA reached the same point in his analysis as LTPA did but then asked the inventor whether there was not some way of using forces other than frictional forces to hold two boards together.

The inventor thought awhile and then said that he supposed one could use a two-headed nail. The two heads would apply opposing forces to the two boards thereby holding the two boards together. The inventor then suggested a modification of his nail structure to a cylinder with a head at one end. The device would be inserted through a predrilled hole in the two boards. The end of the device projecting out of the hole would be hammered into a second head.

Based on this disclosure by the inventor, RPA comes up with the following claim:

RPA's Claim - A device comprising an elongated body for fastening two overlapping boards together, the device exerting forces on the two boards in opposition to any forces tending to pull the two boards apart after the device is inserted in the two overlapping boards.

In order to protect a two-headed embodiment of the inventor's invention, RPA specifies "forces" rather than "frictional forces". By omitting a single word from the claim, RPA has substantially broadened the scope of the claim. Further questioning of the inventor by RPA as to structures capable of "exerting forces on the two boards in opposition to any forces tending to pull the two boards apart" causes the inventor to conceive of a screw and a nut-and-bolt. These two devices also come under the umbrella of RPA's claim as a result of substituting "forces" for "frictional forces."

We now come to "Master Patent Attorney" (MPA) who probably only exists in our imagination. Our imaginary MPA possesses the intellect, training, skills, and experience to construct claims of the highest quality.

MPA covers the same ground with the inventor as RPA did but extends the inventor's disclosure by encouraging the inventor to think of other ways of fastening or holding things together. Our inventor having a familiarity with a variety of technologies, gives his imagination free rein and suggests paper clips, prong fasteners, and loose-leaf hinged rings for holding sheets of paper together, magnetic strips for holding refrigerator doors closed, book ends for holding books together, ropes and straps for holding all kinds of things together, and adhesives for holding almost any objects together.

Our inventor's spewing of ideas for fasteners leads MPA to the highest-quality claim imaginable:

MPA's Claim - A device for fastening a plurality of things together.

I have made the process of arriving at the highest-quality claim seem very simple and straightforward. The process seems simple and straightforward because I have made the unrealistic assumption that there is no prior art pertaining to the subject matter of the invention. In most cases there is prior art to be concerned about and the task of constructing a high-quality claim may be very difficult and time-consuming. Even though high-quality claims may be difficult to come by, the applicant for a patent should not settle for less since they are the true measure of the protection provided by a patent.


© 2002 Robert Malm