Misery loves prior art

Last month, I had to make up an exercise for patent agent trainees (that’s the “misery” part — not making up exercises, but training for the patent agent exams). The exercise itself was the preparation of a response to a examiner’s report, in which a patent examiner raised a number of objections to a patent application. The exercise response required amendments to the patent application, and argument why the prior art located by the examiner did not render the claimed invention obvious.

Naturally it’s fictitious — that is, the examiner’s report is fictitious, and the patent application at issue is adapted from a real patent or application, usually tweaked a bit in order to introduce more errors or uncertainty. The subject matter is usually something simple and mechanical, because the patent agent exams deal with relatively simple mechanical inventions which, in theory, do not require specialized knowledge to understand. (In practice, everybody but the mechanical engineers seems to claim a disadvantage.) So of course, I decided to use a patent for a knitting-related device. The subject matter is simple and mechanical, knitting skill is not actually necessary to be able to understand the invention, and there are few other opportunities to introduce knitting into a patent practice.

The patent I picked on was the one for Knit Klips clips, which were designed for seaming knitted pieces. Unlike the knitting needles with measurement markings, the Knit Klips patent claims generally seem to be fairly true to the product that is actually on the market. (Technically, the patent wasn’t a patent yet when I used it for the exercise — as you can see from the first link, the issue date was in March. But it was on the verge of issuance.)

If you look at a diagram of the clip (especially the ones on the company’s website), it isn’t hard to figure out what how it works.

And, to amuse yourself, before you click the “more” link, ask yourself just what sets these clips apart from any other clips you might have seen in the past. What the inventor (through her agent) and the patent examiner thought were inventive is discussed below the jump.

First, here’s the broadest patent claim that issued:

1. An apparatus which will aid in substantially eliminating misaligned rows when securing adjacent edges of one of knitted and crocheted panels together by securing edges such adjacent edges of a pair of panels of a garment to be darned, said apparatus comprising:
     (a) a first member having a handle portion on a first end and a jaw portion on an opposite end;
     (b) a second member having a handle portion on a first end and a jaw portion on an opposite end, said second member engageable with said first member;
     (c) a securing means engageable with said first member intermediate each end thereof and said second member intermediate each end thereof for securing said second member to said first member;
     (d) an aperture formed through a jaw portion of one of said first member and said second member;
     (e) a post member extending outwardly from an inner surface of an opposite one of said first member and said second member, said post member disposed in a position to extend through said aperture, said post member for engaging such pair of panels to be darned and securing such panels in place where only said post engages such panels; and
     (f) a biasing means engageable with said handle portion of said first member and said handle portion of second member for biasing said apparatus in a closed position.

This is in fact very close to the broadest claim that was originally filed with the application. When the application was originally filed, “post” actually read “post like”, and the phrase “where only said post engages such panels” was not present.

A surprising feature of patents is that sometimes, the simpler the idea, the longer the claims. The fact is, each of the necessary components of a device, and each of the features that distinguishes it over the prior art, needs to be explained. I expect you’re probably thinking “why, this clip here is just a spring-biased clip that opens and closes, dammit, with a substantially smooth post protruding out of one of the clip’s faces, and a hole in the other face for receiving the post, so that layers of fabric pierced by the post can be held together when the clip is closed. And that description’s only about 50 words long, if you drop the ‘dammit’. What’s with all the verbiage?” (Indeed, refraining from even soft profanity is a good tip when drafting patents.)

The problem is, such a description is deficient, patent-wise, as claim. Each element needs to be introduced a first time with an indefinite article; you can’t start calling things the face without first introducing the concept of a face. But if you say “clip”, even if the patent describes one example of a clip, do you mean a paper clip, clothes pin, banana clip, what? If you say “clip” without providing further detail in the claim, are you dooming the patentee to a claim construction that covers only the exact type of clip that was described in the patent and its drawings? And exactly where should the post be positioned with respect to that hole? The claim above, you see, attempts to address these questions.

As a bit of an even further aside before we even get to the prior art, you might be wondering about some of the language chosen for the claim. I did, too. Now, I don’t mean to criticize another person’s patent drafting style, because there is no one “right” way to draft a patent description or claim. (There are lots of right ways, and lots of wrong ways, and while some ways are better than others, you don’t really know if a patent claim is good enough until it gets litigated. If you give a description of an invention to five patent agents, you should wind up with five different sets of claims. If any of the claims are the same, they’re cheating. Different people prefer different terminology and claims structure; that’s just the way it is.)

But still, I found myself wondering if my own knowledge was somehow lacking in respect of the knitting or crafting vernacular, because I had never heard anybody that I’d consider skilled in the art (any knitter, actually) refer to the act of joining two pieces of knitting together as “darning”. “Darning” flaws in fabric already knitted, crocheted, woven, or otherwise manufactured, certainly; but I’ve never seen it as a substitute for “sewing”, “seaming”, or just plain “joining”. The all-seeing, all-knowing, and occasionally unreliable Internet suggests that “darn” is not a substitute for this act of joining. So, why was “darning” chosen as the mot juste when a term like “joining” could be used? Is it not implicitly limiting to describe the act as “darning”? And who chose the term — the patent agent or the client?

Now, on to the prior art. As I said, I picked on this patent because I was preparing an exercise. And as part of this exercise, I needed prior art as a basis for an objection that the clip was not patentable, because it was old or obvious.

I started with the art that was cited in during the prosecution of this particular patent application. There were a number of patents listed, and were mostly directed to clips — clothespins, hair clips, clips for locking various things — but none of them appeared to be too close; in fact, the arguments necessary to overcome these prior art references seemed… well, obvious to me. You can see three examples of the cited prior art located by either the examiner or the inventor to the left. The bottom clip is the one that was used by the examiner to initially reject the patent application’s claims. (It’s actually part of a locking system for securing a portable computer, but arguing that the intended function of a device is different than that of your invention is frequently a non-starter during examination.)

During examination, the examiner concluded that this bottom clip possessed the structural limitations of that claim 1, above. You might not think that this prior clip possesses the “post” and the “aperture” of the claim; it appears to have two teeth that fit together side by side when the clip is closed, so that one tooth on one side of the jaw fits into a void in the opposite jaw. But to the examiner, it was a “post” and “aperture”: the examiner pointed out that there was no positive definition of a “post” and an “aperture” in the patent application, so based on the broadest reasonable interpretation of the claim language, an aperture could be an “opening or open space” (a dictionary definition).

The inventor (through her agent) argued against this, pointing out that the pending claim indicated that the aperture was formed through a jaw portion of the clip, and this was not the case in this prior art clip. (The examiner probably didn’t use the middle clip in the above illustration because it did not open and close the same way as the Knit Klips clip.) In addition, the inventor also pointed out that the post penetrated the knitted panels, and that the interlocking nature of the jaws of the prior art clip would make holding the panels in position difficult. Eventually, the examiner relented and agreed that the fact that only the post in the Knit Klips clip would engage the fabric made it inventive over the prior art clip, where both the “post” and “aperture” engaged the fabric — hence that amendment I mentioned before, which added the phrase “where only said post engages such panels”.

Back to my fictitious examiner’s report. I needed to guard against clever students who, given a copy of a modified Knit Klips patent application (with all ownership and serial number information removed), would search for and locate the real thing, and find a “right” answer by copying the arguments that had really been submitted. Plus, since the arguments to be made over this prior art seemed pretty easy to figure out, I set out to look for something else. After some unenthusiastic searching of tool and medical equipment websites, I started looking through patents and came up with this:

It’s from a patent for a shower curtain ring. The circle marked 14 is a cross-sectional view of a shower curtain rod; the vertical bit marked 12 is the shower curtain. Like the Knit Klips clip, you can squeeze the finger grips to open it, and now you have some protuberance — not a straight post — emerging from one side of the jaw, that does fit into a hole in the other side of the jaw. When this clip is closed, the bit of the protuberance labelled 50 is still exposed, and the shower curtain 12 can be suspended from that bit.

So the exercise left to the reader, essentially, is this: you can imagine that if this shower curtain clip were used to hold two pieces of knitted fabric together, they would be suspended from the bit of the protuberance 50, which as shown here, is curved. Thus, this shower curtain clip does not suffer the same problem as the previous prior art clip; only the “post”, curved though it is, engages the panels to be “darned”. Given this fact, does the claim reproduced above adequately distinguish the knit clip over this piece of prior art, or what amendments must be made to the claim?

And remember, there is no one right answer.

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6 Responses to Misery loves prior art

  1. Shannon says:

    I feel much better now that I know I’m not the only one you like to give questions with diagrams… ;)

  2. j. says:

    Part 60 of the shower curtain ring will engage with the aperture 50A, and I assume will be stopped from entering through the aperture further either because of the way the clip is biased with the spring or other resilient means used to close it at the hinge, or because the hump 50 will prevent that bit of the curtain ring from engaging further into 60. I didn’t post the other figures from this patent, but there is a drawing of it when it’s closed.

    But according to claim 1 of the Knit Klips patent, it’s the first member that is engageable with the second member, not the jaw portions of the members; the post member must be in a position to extend through the aperture. (The first and second member engageable is probably referring to the hinge; I can’t remember what the description said right now.) So to me, this comes down to whether the “post member” of the claims is disclosed by parts 50 and 60.

  3. Isabel says:

    Just so the knitters in patent land are represented: tricky… are the two “jaw ending” parts of the shower curtain really “engaged” with each other?

  4. Jen says:

    That is a really good argument for specificity, huh?

  5. sarah says:

    S/he used ‘darn’ because, after spending several aeons writing and re-writing the application, it was the only way they could think to express their frustration by inserting an expletive into the text. Those damned panels were responsible for the agony…

    Thank you for taking the time to post these intriguing insights into a world of which I knew absolutely nothing until I subscribed to your blog.

  6. kmkat says:

    Hmmm. Sounds like the arcana of patent writing and approval is just about as complicated as the Internal Revenue Code. And just about as as fascinating to non-participants as the IRC is to non-accountants. Not that that is a bad thing, just that we often are forced to become very, very specialized in order to do our jobs.