PTAB Decides That Mere Common Sense Is Not Sufficient In Lieu Of Expert Testimony

April 16, 2015


In its Inter Partes Review Final Written Decision, the Patent Trial and Appeals Board (PTAB) found that Petitioner had shown by a preponderance of the evidence that method claims 16 and 17 of U.S. Patent No. 5,544,417 (the ’417 Patent) are unpatentable, while finding that Petitioner had not proved by a preponderance of the evidence that apparatus claims 7 and 10 which are similar to the method claims 16 and 17 of the ’417 Patent are unpatentable.  Positec USA, Inc. and RW Direct, Inc. v. Black & Decker Inc., (IPR2013-00502, Paper No. 35, January 29, 2015).

Claims 7 and 10 of the ’417 patent are directed to a vegetation cutter in the form of a string trimmer. A motor is supported within a housing of the device by being “fixedly secured” to a mounting plate “without the need for a plurality of ribs to be formed on interior surfaces of the housing of the string trimmer.”  (Paper No. 35 at page 3).  The Petitioner relied on the combination of two references, the string trimmer of Laverick and the hair trimmer of Mack.  The Petitioner argued that one of ordinary skill in the art predictably would have modified Laverick to use a motor secured to a mounting plate having grooves, as in Mack, and that the resulting groove/plate connection would have been dimensioned in order to freely support the motor within the housing without contacting the interior of the housing.  (Paper No. 35 at pages 18 and 19).  The Petitioner did not rely on any evidence, such as an expert declaration, to support their arguments.

Petitioner argued, citing Wyers v. Master Lock Co., 616 F.3d 1231, 1239 (Fed. Cir. 2010), that expert testimony concerning whether Laverick and Mack can be combined is not required.  Instead, Petitioner expressly argued that “[l]ogic, judgment and common sense all point a person of ordinary skill in the art to look to other small electric tools or appliances for a possible solution, and combining Mack and Laverick would have been entirely proper.”  (Paper No. 35 at page 19). In the Patent Owner’s Response, which included the Declaration of Philip J. O’Keefe, PE (Paper No. 69), the Petitioner asserted that “the miniature, low power DC motor in the hair trimmer of Mack is permitted to move or wobble,” which would not prevent relative movement as required by the “fixedly secured” limitation. (Paper No. 35 at page 20).  In consideration of the full record after a trial, the PTAB agreed with the Patent Owner’s argument that Mack fails to disclose the motor being fastened such that the relative movement of the motor is prevented.

Take Aways

Under KSR v. Teleflex, in analyzing the obviousness of a combination of prior art elements, it is important to identify a reason that would have prompted one of skill in the art to combine the elements in the way the claimed invention does, not just that the prior art could be combined in that manner.  For identifying such reason, merely relying on common sense of the skilled artisan without some evidentiary support is not sufficient.



Young Chon


Mr. Chon is a member of the firm’s Electrical/Mechanical Patent group. Mr. Chon’s practice focuses on the preparation of the Mechanical patent applications as well as the prosecution of these applications before the U. S Patent and Trademark Office.

Mr. Chon was previously employed with Pratt & Whitney, a United Technology Corporation Company, and he has more than 10 years of aerospace industry experience in engineering, strategy / business development and operations. His roles have included Joint Strike Fighter F-135 Senior Engineer, Commercial Engines (CE) Technology Licensing Specialist, CE Joint Ventures and Partnerships Specialist and Operations Export Compliance Manager.

Mr. Chon is an inventor listed on several patents in the art of gas turbine airfoil design.