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MPEP 2143.01(V) July 11, 2008

Posted by Brian Schar in Patent prosecution, USPTO.

Patent prosecutors are familiar with cafeteria-style rejections under 35 U.S.C. 103, where the Examiner collects 3 or more references and picks an element from each to cobble together an obviousness rejection.  Particularly annoying are rejections of that sort in which the Examiner cites patents from completely different technology areas – combining a surgical stapler with some kind of carpentry hardware from the 1800s, for example.  (I’d insert a statement here that this has actually happened to me, but if you’ve been in practice for any reasonable amount of time, a similar thing has happened to you.)

Pre-KSR, one might have argued that there is no motivation to combine such references.  Post-KSR, one can still make that argument.  MPEP 2143.01(V) expressly states that a proposed modification of a prior art invention cannot render that invention “unsatisfactory for its intended purpose.”  If it does, “there is no suggestion or motivation to make the proposed modification.”  MPEP 2143.01(V) gives the example of a gasoline filtration device with an inlet and outlet at the top of the device and a stopcock at the bottom of the device for draining collected dirt and water.   The BPAI found claims to a blood filter obvious over that gasoline filter, on the grounds that it would be obvious to turn the gasoline filter upside down.  However, the Federal Circuit found that turning the gasoline filtration device upside down would render it unsuitable for its intended purpose, because the water and dirt would flow out of the outlet rather than becoming trapped, and that gasoline would rise to the stopcock and become trapped.

When confronted with a pick-and-choose obviousness rejection, this provision of the MPEP can be very useful.  When an Examiner writes a rejection that simply picks element A from one reference, element B from another, element C from a third and element D from a fourth, he or she typically is just looking for parts for cobble together, and rarely considers how they would function as a whole.  If any of elements B, C or D render the invention of the first reference unsuitable for its intended function, then each such element cannot be combined with the invention of the first reference.  As the number of references and their unrelatedness increases, the greater the chances that the addition of at least one of those references renders the base, prior art invention unsuitable for its intended purpose.

The summary and any objects listed in a reference patent or published patent application can be very useful here.  For example, if an object of the invention of a first reference is, for example, to provide a volume in which a workpiece object is kept dry, and element B from a second reference is identified as analogous to that space but requires that the space be at least partially filled with fluid at all times, then the second reference cannot be combined with the first under MPEP 2143.01(V).  Filling that space in the first reference would run contrary to the object of the invention, thereby rendering that prior art invention unsuitable for its intended purpose.

Next up: MPEP 2143.01(VI).


1. Ryan Flax - July 15, 2008


I like your blog and your comments about KSR and “intended purpose” are useful. Keep up the good work.

And, since I see you’re a fan of interviewing cases at the PTO, next time you’re sight-seeing over the weekend before your interview, check out the national park at Great Falls. Most tourists never see this and it’s pretty interesting.

2. Ashwini - January 22, 2009

Dear Brian,

I really liked your posts related to Patent Prosecution, especially, this one. I am a recent LLM graduate, begining a career (or rather trying to) in Patent Law in the US. Your post has simplified many things that can be troublesome for a newcomer in the field. I really appreciate the simplicity of your writing. Is there a way to contact you regarding further questions on this topic? I would highly appreciate,if you can provide further guidance in this regard. Thank you for your time. Hoping to read more from you.

Best regards,

3. MPEP 2143.01(V) in action « American IPA - November 28, 2011

[…] If it does, “there is no suggestion or motivation to make the proposed modification.”  An older post analyzes this section in the MPEP in […]

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