Earlier this year, the Federal Court of Appeal had the
opportunity to revisit the law of contributory infringement in the
case of MacLennan v. Produits Gilbert Inc.
Contributory infringement, also known as infringement by
inducement, occurs when the defendant is not directly infringing a
patent, but is knowingly encouraging others to do so. Under
Canadian law, a plaintiff claiming contributory infringement must
prove three elements: that there is direct infringement by another
party using a component supplied by the defendant; that the
defendant knew that infringement is taking place; and that the
defendant encouraged the infringing conduct.
The patented invention was used in the logging industry. The patent
in question was a combination patent that described how three
different parts of a feller head (the sharp end of a saw used in
logging) worked together. The three parts of the feller head are
the disc, the teeth holder, and the teeth. Of these, the disk is
the most expensive component, followed by the holder, followed by
the teeth. When the saw is used, it is used as close to the base of
a tree as possible, and the saw will often strike rocks or other
objects that can damage it. The plaintiffs' patent described a
method for connecting the three components so that when the saw
does strike a rock, first the teeth, and then the teeth holder will
break away, leaving the disc undamaged. In this way, the less
valuable components are sacrificed to save the more valuable ones.
The teeth are essentially disposable: their loss or damage is
expected, and replacements are routinely kept on hand.
The defendant, Produits Gilbert Inc. (Gilbert), was in the
business of selling replacement saw teeth. These teeth were made to
fit into the plaintiffs' teeth holder, and would also break
away to avoid damage to the disc. The plaintiffs did not claim that
the individual teeth designs were patented, only their use in
combination with the teeth holder. Therefore, on the facts of this
case, if any direct infringement was occurring, it was when the
loggers themselves combined the defendant's teeth with the
plaintiff's teeth holder.
The Court had to decide whether the three elements of
infringement by inducement were present in this case. At trial, the
judge ruled that there was no direct infringement because when a
patented object is purchased, the buyer is entitled to repair the
effects of ordinary wear and tear. The trial judge had found that
replacing broken teeth was a repair, and therefore no infringement
was taking place.
The Court of Appeal disagreed, finding that the essence of the
protected invention was the combination of the teeth with the teeth
holder, and that combination was recreated every time the teeth
were put in place. The loss and replacement of teeth during the
operation of the saw was not wear and tear; it was what the
patented combination was designed to do. When the loggers replaced
the teeth they were remaking the combination, and when they used
the defendant's teeth, they were infringing the plaintiff's
The Federal Court of Appeal affirmed the more onerous test for
contributory infringement under Canadian law. In Canada (unlike the
United States and Great Britain), for contributory infringement to
be found (assuming the direct infringement has been established
using a component supplied by the alleged contributory infringer),
two further elements are necessary. First, the alleged contributory
infringer must know that its contribution will be used to infringe.
Second, the alleged contributory infringer must encourage the
The loggers' infringement would only be Gilbert's
responsibility if Gilbert had knowingly encouraged it. Since
Gilbert's teeth were only suitable for use in the
plaintiffs' teeth holder, there was no question that Gilbert
knew that their product would be used to infringe. In considering
the issue of encouragement, the Court looked to Gilbert's
marketing material, and pointed to price lists that named the exact
models of the plaintiffs' teeth that the Gilbert teeth were
designed to replace. The Court found that this amounted to telling
the loggers how to use the Gilbert teeth to infringe the
plaintiffs' patent. Gilbert believed it was necessary to
indicate the intended use of the teeth in order to sell them. When
Gilbert informed its customers that its teeth were intended to
replace the plaintiffs' teeth in making the patented
combination, it encouraged them to infringe the patent.
The content of this article is intended to provide a general
guide to the subject matter. Specialist advice should be sought
about your specific circumstances.
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A recent Saskatchewan Court of Queen's Bench decision allowed a court-appointed receiver to sell and transfer intellectual property rights free and clear of encumbrances, finding that a license to use improvements of an invention was a contractual interest and not a property interest.
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