Facts: Plaintiff owned various patents for hop-picking devices that were embodied in a machine sold for a flat fee.  Additionally, there was an annual license fee charged for use of the machine.  The royalty was based on the amount of hops harvested.  By their terms, licenses could not be assigned, nor could machines be removed from Yakima County.  The patents involved all expired on or before 1957, but the licenses required that royalties continue to be paid after that date.  Defendant refused to make payments accruing both before and after expiration of the patent.  The trial court held for plaintiff.

Issue: Is defendant required to pay royalties?

Holding:  Only before patent expired, but not after.

Reasons: Restrictions in license agreements are pertinent to the patent monopoly; their post-expiration applicability is a telltale sign that plaintiff was u-sing the license to expand the monopoly beyond the statutory patent period.  The sale or lease of unpatented machines on a deferred purchase price arrangement would present wholly different considerations.  This license draws no distinction between pre- and post- expiration terms.  The same royalties and limitations were applicable to both.  Such a license, which so expands the patent monopoly, is unlawful per se.

Harlan dissenting:

Plaintiff Thys. could have sold the machines on credit for terms longer than the patent period.  True, a person may not restrict use of a patented idea once it has fallen into the public domain.  Defendant then may buy another kind of machine embodying Thys's idea.  But he is not entitled as against Thys. to the free use of his machine.  It seems the thrust of the major opinion is that plaintiff must redraft the contract to obtain some economic results.