Thursday, April 10, 2014

Obviousness is Objective

E Mishan & Sons, Inc v Supertek Canada Inc 2014 FC 326 Hughes J

Mishan v Supertek is a straightforward case which illustrates the objective nature of the obviousness inquiry [128]. The inventor believed he had invented an ingenious new type of garden hose, but he was not aware of a key prior art patent which rendered the invention obvious.

The problem addressed by the 882 patent was that of unwieldy garden hoses, which are difficult to store and unravel because of their length. The solution provided was a hose consisting of a elastic inner tube contained within an outer fabric tube, with the tubes coupled to each other at each end. Under pressure, the inner tube would elongate until constrained by the outer tube. When turned off, the inner elastic tube would contract, causing the hose to shrink. The inventor had developed the hose primarily for use as a residential garden hose, but the specification stated that it could be used to convey “fluid” including water, gases and even flowable solids [138]. The prior art was US patent 6,523,539, the McDonald patent, which was titled “Self-elongating oxygen hose for stowable aviation crew oxygen mask.” It operated in essentially the same way as the plaintiff’s hose. The main difference between the McDonald invention and the 882 patent was that the former was intended for air supply in aircraft and for conducting oxygen or air. Given the minor difference, and the fact that the 882 patent stated that it could be used for fluids generally, it was relatively straightforward for Hughes J to conclude that the 882 patent was obvious over McDonald.

 McDonald patent

882 patent

Consequently, there was an important question as to whether the McDonald patent was part of relevant state of the art. On the facts, the answer was straightforward: “McDonald was not only findable but found by those interested in expandable hoses. There is no evidence to the contrary” [91].

Commercial success and motivation were argued as showing invention:

[144] There are a number of secondary factors that have been raised. There was motivation to create a simple, inexpensive garden hose that could be promoted in the direct retail market by television advertising and the like. It was a commercial success. But motivation and success alone do not mean that there was, in the objective sense, an invention. Khubani testified to that when he referred to items such as amber sunglasses and dust mops that had been available for years but were great successes in the direct retail environment.

The inventor of the 882 patent did not begin his research by doing a search of the patent prior art, and apparently the same is true of garden hose designers in general. If they had, the patentee’s solution would have been arrived at sooner. The notional skilled person is probably not as clever as real-world inventors, but she may sometimes be better informed about the prior art.

Note that the costs awarded to the defendant were reduced because it had raised too many issues on which they were unsuccessful. This is a message from Hughes J that the case should be restricted to the real issues [162].


  1. Interesting to see that in the UK the opposite was found.

  2. Good point. Hughes J noted that himself at [38], though I have to admit I hadn’t read the UK decision when I wrote my post. I’ve taken a look at it now. The key reasoning concerning obviousness over McDonald is at [100]. Birss J held in effect that a garden hose designer wouldn’t really trust the McDonald teaching because it was so far from the field of garden hoses. While this is one of those issues that is difficult to assess from the opinion alone, as it turns on an appreciation of the evidence, I am inclined to prefer Hughes J’s position. I get the sense that Birss J was trying to evade the objective nature of the obviousness inquiry. It is clear that the inventor developed the product on his own, without reference to the McDonald patent, and it seems clear that absent the McDonald patent, the patented invention really was an ingenious contribution to garden hoses, as evidenced by long-felt need, commercial success, and failure by others to solve the same problems. It also seems that the inventor really was relying on patent protection to make his money, and that the defendant copied the product from the patentee [61]-[63]. So, in the real world of garden hose design, there was invention, and there was also the kind of free-riding on the ingenuity of others that the patent system is designed to prevent. This drives a strong intuition that the patent should be valid and infringed, which is I think what was driving Birss J. But on the specific question of obviousness over McDonald, I think that Hughes J’s analysis was more convincing. If there is a problem with the result, it lies in the somewhat unrealistic nature of the legal definition of the state of the art. A real world garden hose designer would not begin by searching the patent prior art, but a posita would. That is why Birss J’s holding seems fair, but Hughes J’s holding is legally correct.