An increasing number of inventors are requesting provisional patent applications. Often, these prospective clients are trying to balance limited resources with the many expenses associated with developing a new product and bringing it to market, and are looking for the least expensive way possible to gain patent pending status. Unfortunately, many are relying on erroneous information about the true nature of provisional patent applications. To avoid compromising the patentability of one’s invention, a proper understanding of provisional patent applications is essential.

Provisional patent applications are not examined. Instead, they are intended to preserve the filing date of their invention disclosure for one year. Before the expiration of that year, a utility patent application must be filed in order to gain the benefit of the provisional patent application’s filing date. Unfortunately, because provisional patent applications are not examined, many inventors attempt to cut corners in preparing these applications, potentially jeopardizing their entitlement to the earliest possible filing date.

In order for the subsequently filed utility patent application to benefit from the provisional patent application’s filing date, the disclosure of the provisional patent application must adequately support the invention claimed in the utility patent application. In addition to providing sufficient detail so that one skilled in the art would be enabled to make and use the invention from the disclosure, the application must also convey that, as of the filing date, the applicant was in possession of the invention. Furthermore, the provisional patent application’s disclosure must show that the inventor had invented each feature that is included as a claim limitation.

Unfortunately, some inventors attempt to take advantage of the fact that provisional patent applications are not examined in order to gain patent pending status as quickly and inexpensively as possible. These inventors file self-drafted provisional patent applications which often contain little more than a brief description of the invention prepared by the inventor, as well as a few basic drawings. After filing such applications, these inventors, believing they have patent pending status, start promoting their inventions, intending to prepare more complete utility patent applications if their invention attracts sufficient interest and funding. These inventors fail to realize that the strength of their claim to their provisional patent application’s filing date may be tenuous at best. Depending on the timing of public disclosures, public use, and/or offers for sale, these inventors risk losing their foreign filing rights, or potentially the validity of their US patent.

The risk of loss of patent rights due to weaknesses in the disclosure of provisional patent applications is quite real, as some inventors attempting to enforce their patents have learned. In New Railhead Mfg., LLC v. Vermeer Mfg. Co., 298 F.3d 1290 (Fed. Cir. 2002), the plaintiff sued alleging infringement of two patents claiming an apparatus and method for horizontal directional drilling of rock. Id. at 1292. The plaintiff’s patents included independent claims which included an angled relationship between the drill bit and a housing. Id. at 1292-93. This feature was not shown or described in the provisional patent application for which the patents claimed the filing date. Id. Because the apparatus was sold more than one year before the filing dates of the utility patent application, loss of the benefit of the provisional patent application’s filing date resulted in invalidity of the patents. Id. at 1294. A more thorough provisional patent application, which included the relationship between the drill bit and housing, would have changed the result.

A similar result was reached in Minemyer v. B-Roc Representatives, Inc., 695 F. Supp. 2d 797 (N.D. Ill. 2009). The plaintiff sued for infringement of a patent claiming a plastic pipe coupler having tapered threads, which are shallow at the ends, and become deeper towards the center. Id. at 798. However, the provisional patent application for which the patent claimed the benefit of the filing date did not disclose this feature. Id. at 804-05. The patent was therefore not entitled to the provisional patent application’s filing date. Id. at 806. Because the invention was offered for sale more than a year before the utility patent application’s filing date, numerous claims within the patent were found to be invalid. Id. at 808. Again, a more thorough provisional patent application would have changed the result.

If foreign filing is contemplated, the filing date becomes especially important. In most foreign countries, public disclosure of an invention prior to the effective filing date negates the right to file a patent application in that country. Many foreign countries require certified copies of the application for which the filing date is claimed. If a provisional patent application does not adequately support the claims of the subsequent foreign application, the effective filing date will be the date of filing in the foreign country rather than the provisional patent application’s filing date. If public disclosure occurred before this date, the patent application will be rejected.

Hastily drafted provisional patent applications are not completely without purpose. If public disclosure is imminent and cannot be delayed, such an application may at least provide the potential for a claim of a filing date that predates the public disclosure. In such a case, a properly prepared provisional patent application or utility patent application should be filed with reasonable promptness thereafter. Furthermore, patents are granted to the first inventor to file a patent application, even if the first inventor to file a patent application is not the first inventor to invent the claimed subject matter. Prompt filing of provisional patent applications can be important if others are likely to be developing similar inventions.

In order to minimize the risk of losing the benefit of your earliest filing date, the following guidelines should be followed:

1. Avoid any public disclosures, public use, and offers for sale of the invention prior to the filing date of a patent application.

2. Make every effort to ensure that the earliest application filed includes as much detail as possible, including all possible features of an invention, and all possible variations of the invention.

3. If circumstances require the filing of a hastily drafted provisional application, follow this application promptly with a more thoroughly drafted application.

4. Consult a patent attorney regarding preparation of patent applications well in advance of any public disclosures, use, or offers of sale of the invention.