Thе determinative issue in this appeal is whether a patent owner’s unrestricted sale of a machine useful only in practicing the claimed inventions presumptively carries with it an implied liсense under the patent. The United States District Court for the Western District of Pennsylvania decided that legal issue in the affirmative. 1 We affirm.
I.
Met-Coil Systems Corp. is the assignee of U.S. Patent No. 4,466,641, which claims an apparatus and method for connecting sections of metal ducts of the kind used in heating and air conditioning systems. Under the claimed inventions, the ends of the metal duct sections are bent tо form integral flanges, specially shaped corner pieces are snapped in place, and the sections are bolted together. 2 Met-Coil makes and sells roll-forming maсhines that its customers use to bend integral flanges in the ends of metal ducts so as to practice the claimed inventions. Met-Coil also sells the specially shaped corner pieces for use with the integral flanges. 3 Korners Unlimited, Inc. makes comer pieces for use with Met-Coil’s integral flanges and sells them to purchasers of Met-Coil’s machines. Met-Coil sued Korners for inducing infringement of claims 1-12, 14-25 of its patent. Korners moved for summary judgment.
The basis of Korners’ motion for summary judgment was that Met-Coil, by selling the roll-forming machine, granted an implied license under the patent to its customers. Because of that license, Korners contended, Met-Coil’s customers cannot infringe the claims of the patent and, thus, Korners can neither induce infringement nor contributorily infringe. Mеt-Coil, on the other hand, contended that its sales of the machines do not confer an implied license under the patent upon its customers.
II.
The district court recognized that “[t]he integral flanges are an essential part of Met-Coil’s patented duct connecting system” and that the “flanges have no use other than in the practice of the duct connecting system.”
In Univis, the patent covered multifocal eyeglass lenses, and the рatent owner sold blank eyeglass lenses to its licensees. The Court held that the sale of the blanks carried a license to complete the lenses:
But in any case it is plain that where the sale of the blank is by the patentee or his licensee — here the Lens Company — to a finisher, the only use to which it could be put and the only object of the sale is to enable the latter to grind and polish it for use as a lens by the prospective wearer. An incident to the purchase of any article, whether patented or un *686 patented, is the right to use and sell it, аnd upon familiar principles the authorized sale of an article which is capable of use only in practicing the patent is a relinquishment of the patent monopoly with respеct to the article sold. Leitch Mfg. Co. v. Barber Co.,302 U.S. 458 , 460-61 [58 S.Ct. 288 , 289-90,82 L.Ed. 371 ] [1938]; B.B. Chemical Co. v. Ellis,314 U.S. 495 [62 S.Ct. 406 ,86 L.Ed. 367 ] [1942]. Sale of a lens blank by the patentee or by his licensee is thus in itself both a complete transfer of ownership of the blank, which is within the protection of the patent law, and a license to practice the final stage of the patent procedure.
... [W]here one has sold an uncompleted article which, because it embodies essential features of his patented invention, is within the protection of his patented invention, and has destined the article to be finished by the purchaser in conformity to the patent, hе has sold his invention so far as it is or may be embodied in that particular article. The reward he has demanded and received is for the article and the invention which it embodies and which his vendee is to practice upon it.
It should be noted, however, that unlike Univis ..., the practice of the final stage of Met-Coil’s patented system rеquires not just “finishing” the element sold, i.e. forming the integral flanges, but also the purchase of an additional element of the patented system, i.e. the corner pieces. Met-Coil cites no аuthority which suggests that this difference takes the present case out of the rule of Univis.
III.
On appeal, Met-Coil urgеs that the district court erred in relying on
Univis.
To support that proposition, Met-Coil cites
Bandag, Inc. v. Al Bolser’s Tire Stores, Inc.,
Met-Coil contends that this case does not meet the two-part test set out in
Bandag,
that is, although the mаchines sold have no noninfringing use, the circumstances do not plainly indicate that the grant of a license should be inferred. In this connection Met-Coil introduced certain written notices to customers with respect to the purchase of comer pieces from unlicensed sources.
4
Met-Coil relies on cases holding that no implied license arises where the original sale was accompanied by an express notice negating the grant of an
*687
implied license.
Radio Corp. of America v. Andrea,
Met-Coil urges that, even though it has not shown that the sales were accompanied by an express disclaimer of license, Korners has not met its burden of proof. As the alleged infringer, Korners has the burden of showing the establishment of an implied license.
Bandag,
The sole disputed issue decidеd by the trial court, the existence of an implied license, is a question of law.
See Bandag,
AFFIRMED.
Notes
.
Met-Coil Systems Corp. v. Korners Unlimited, Inc.,
. Although Mеt-Coil attempted to obtain claims directed to the corner pieces, it was unsuccessful. The corner pieces are unpatented.
. Met-Coil’s wholly-owned subsidiary, Lock-former Co., and its licensee, Engel Industries, Inc., manufacture and sell the roll-forming machines used to form the flanges in ducts. Another Met-Coil wholly-owned subsidiary, Iowa Precision Industries, Inc., manufactures and sells cornеr pieces for use in Met-Coil’s claimed inventions. For convenience, we refer to Met-Coil rather than its subsidiaries or its licensee.
. Met-Coil’s subsidiary Iowa Precision Industries, Inc. sent a letter to owners of Lockformer machines and distributors of Iowa Precision’s corner pieces, notifying them that "as long as you are a customer of ours, you are automatically licensеd to use the [claimed invention] insofar as your use involves forming rolls and corners purchased from us but not from other unauthorized sources.”
. Because our review is limited to the case befоre us, we emphasize that this case does not involve sales accompanied by a notice expressly precluding the grant of a license under the patent. Nor do we express any opinion on the legality of requiring the combined purchase of a machine and corner pieces. Moreover, our affirmance of the district court's holding that Met-Coil’s customers enjoy an implied license prevents us from reaching the arguments raised by Met-Coil as to why Korners’ sales are infringing.
