When drafting a patent application, there can be parts of an invention that seem “peripheral” or “well known” and thus may receive less attention and detail in the description. Further, in-house counsel reviewing an application may find to much focus on such elements as superfluous and wasted effort, unnecessarily reducing drafting efficiency. And with the never-ending pressure on patent drafters to be more efficient and less costly, short-shrifting the description of such aspects can become common practice. However, cutting out details, even of what are well-known elements of an application, can lead to significant unintended consequences.

Today we review an application (15/185,541) for a directed to a tail stock for a long vertically suspended workpiece that will experience heat expansion. Claim 1 on appeal is below:

1. A tailstock assembly for supporting and processing a workpiece along a vertical rotary axis comprising:

a base member;a housing having a wall including a first end, and a second end, an outer surface, and an inner surface defining a central passage extending between the first and second ends defining a longitudinal axis, the second end being coupled to the base member;

a workpiece support extending through the central passage, the workpiece support including a first end, a second end and an intermediate portion extending therebetween; a rotating member rotatably connected to the workpiece support;
a thermal processing device positioned proximate to the rotating member, the thermal processing device including one of a sintering device and a thermal spray processing device;

a linear bearing coupled to the base member in the central passage, the linear bearing slideably receiving the first end of the workpiece support; and

a displacement sensor assembly including a stationary portion mounted relative to one of the base member and the housing, and a moveable portion mounted to the first end of the workpiece support, wherein, during use the displacement sensor measures an amount of movement of the workpiece support relative to the base member, the processing device being shifted relative to the workpiece support an amount corresponding to the amount of movement of the workpiece support.

One issue in the case was the proper interpretation of elements such as “thermal processing device,”
“sintering device,” and “thermal spray processing device.” The examiner alleged that these were means plus function elements (see one of our past posts on means plus function here).

You may be thinking that the worst case scenario is that the claim elements might have a narrower scope. While that surely could be a less than optimal outcome, the real show-stopper comes when one realizes that the specification here has no further details of those elements beyond repeatedly referring to them with the same functional language. The problem thus is that such elements, if recited in the claims, cause the claims to be invalid (see cases such as Diebold Nixdorf Inc v Int’l Trade Comm’n (899 F.3d 1291 (Fed Cir 2018)). In other words, claiming an element as a means plus function, where the specification does not disclose any corresponding structure, causes the claim to be invalid.

Here, the specification had no further details on these elements, and the PTAB agreed therefore that the claims were invalid under Section 112.

Can the applicant rectify this issue by simply removing these elements from the claim? Perhaps, but when one turns to the obviousness analysis by the PTAB, the PTAB confirms that claims are inventive and non-obvious because of a combination of features including these means plus function elements.

So, in the end, the applicant has a novel and inventive claim, but is hamstrung with a specification has give insufficient structural detail in the specification of certain elements. This creates what appears to be an un-curable fatal flaw in the detailed description due to the pedantic means plus function rules in the US.