Earlier Provisional Filing Date Only if the Provisional Application Contains Adequate Written Description

Even though the law does not require claims in a provisional application, the law does require that any inventive elements claimed in a nonprovisional application be disclosed in the provisional application. In other words, if new matter is introduced in the formal claims, those claims will not get the benefit of the provisional application’s filing date. Thus, a patent practitioner must be as thorough as possible in order to avoid inadvertently narrowing the scope of potential claims later in the life of the patent application.

New Railhead Mfg. LLC v. Vermeer Mfg. Co.
Prior to the dispute with Vermeer Mfg, New Railhead had filed a provisional application describing a horizontal rock drill bit wherein “the unitary bit body [is] angled with respect to the …housing.” The provisional was filed less than one year after the invention was sold. Subsequently, New Railhead filed a related non-provisional application claiming the filing date of the provisional application.

Identifying Vermeer as a potential infringer after the patent had issued, New Railhead sued the defendants, and the case was brought before the Federal Circuit. In their defense, the accused infringers argued that the provisional patent did not fully describe the invention later claimed in the nonprovisional patent.

The Federal Circuit found that that “nowhere in the provisional application is the bit body expressly described as being ‘angled with respect to the… housing’ as recited in claim 1.” As a result, the patent holder lost the benefit of the provisional application’s filing date, and a judgment of invalidity was upheld.

Practice Points
Thus, when drafting a provisional patent application, a practitioner must remember that formal claims, if not discussed in a provisional application, may lose their priority date established by the provisional application.

One may guard against this eventuality by articulating all possible iterations of the invention in the provisional detailed description, using broad language, and incorporating several statements pointing out that the description is intended as a disclosure of “presently-preferred embodiments of the invention and is not intended to represent the only forms in which the present invention may be constructed or organized.”