Many inventors file provisional applications as a first stage in applying for a patent. Provisional applications can be filed without claims, so the inventor does not have to decide which features will distinguish the invention over the "prior art," and since provisionals are not examined, they can be filed without the usual formatting of a conventional patent application. Provisional applications can thus be filed quickly and inexpensively and will receive an official filing date in the Patent and Trademark Office that can serve as a cut-off date for prior art and also as a date that may be useful if the application becomes involved in an interference, i.e., in which it competes with another application for rights to the same invention. Many inventors actually prepare their own provisional applications.
Provisional applications allow inventors to reserve a filing date while postponing the decision as to whether or not to seek patent protection. If patent protection is ultimately sought, the filing date of the provisional can be transferred to a non-provisional application provided that the non-provisional is filed within one year. Unfortunately, many inventors believe that even a hastily prepared provisional application can prevent subsequent publications or commercial activity from having the status of prior art. Similarly, inventors tend to believe that any provisional application filed within the one-year grace period following the inventor's own publications and commercial activity will prevent such publications and commercial activity from voiding the inventor's chances for a patent. The truth is that there must be a very close relationship between what the provisional application describes and what the patent ultimately claims if the patent is to have the benefit of that early filing date. This was articulated in a recent case in the horizontal drilling industry.
Horizontal or "trenchless" drilling is used for oil and gas exploration in stratified earth formations and for forming boreholes underneath roadways and bodies of water for the placement of utility conduits. Horizontal drilling equipment typically includes a drill string terminating in a directable drill bit and a sonde that sends positioning data to a receiver on the ground surface. Traditionally, horizontal drilling systems have been unable to drill through rock despite their use of high-speed fluid jets to steer the drill bit and cool the drill body and blade. The invention in U.S. Patent No. 5,899,283 overcame this limitation by offering an asymmetric drill bit whose body is angled with respect to the sonde housing and drill string. The body of the drill bit thus has a toe extending below the axis of the sonde housing and a heel extending above the axis. With end studs protruding from the tip of the toe, the bit rotates intermittently in a random, orbital motion that allows the studs to fracture the rock at one location and then move to another location at a different angle relative to the axis to resume fracturing. The rotation of the angled bit body relative to the sonde housing axis produces a borehole whose radius exceeds that of the bit itself. The claims of the patent thus include the phrase "the unitary bit body being angled with respect to the sonde housing" as a critical feature of the invention.
The invention was first filed as a provisional application, followed nine months later by a non-provisional application from which the patent issued. Approximately six months before the provisional application was filed, the inventor's company made commercial sales of several drill bits containing the angled feature. Since the grace period for applying for a patent after a commercial sale is one year, the patent needed the benefit of the provisional application filing date to be valid and enforceable. The ability of the provisional to provide this benefit was challenged when the patent owner sued a competitor for patent infringement.
The non-provisional application and hence the patent itself described the angled relationship between the bit body and the sonde housing in both text and drawings. The provisional application, on the other hand, merely referred to a "high angle of attack," an "asymmetrical geometry," "offset drill points," and a "trailing shoe," failing to actually state that the bit body was at an angle with the sonde housing axis. The drawings in the provisional showed the bit body and the sonde housing in separate views but not joined. When questioned, the inventor testified that if one were to construct the parts from the drawings and combine them, the resulting drill bit would be angled as claimed in the patent. The court reasoned that even if this were true, a more explicit disclosure of the feature, either in the drawings or the text, would be needed to support the claim language. As a result, the patent was not granted the benefit of the filing date of the provisional application, and this caused the patent to be declared invalid. This demonstrates that provisional applications should always be drafted with great care and a view toward the nonprovisional even though the decision to proceed with a nonprovisional has yet to be made.
Reproduced with permission from Chemical Engineering Progress