Cincinnati Milacron Inc. is warning several competitors that they could be violating Milacron's patent for using a ``general-purpose'' computer in the operator station panel of an injection molding machine.
Milacron issued the warning in a letter signed by Stephen Friskney, senior patent lawyer. Milacron competitors say they received the letter early this month.
In the letter, Milacron requests a royalty of 5 percent of the selling price of machines that violate the patent. Milacron also is proposing a licensing agreement, or another negotiated settlement.
As of late last week, at least five companies confirmed they had received Milacron's patent letter: Engel North America of Guelph, Ontario; Krauss-Maffei Corp. of Florence, Ky.; Netstal-Machinery Inc. of Fort Devens, Mass.; Sandretto Plastics Machinery Inc. of Middleburg Heights, Ohio; and Van Dorn Demag Corp. of Strongsville, Ohio.
Contacted Sept. 18, Tom Jarrold, spokesman for Cincinnati Milacron's Plastics Machinery Group in Batavia, Ohio, confirmed that Milacron sent the letter, but he declined to comment further. Jarrold would not say how many of the letters Milacron sent.
The dispute involves U.S. patent No. 5,062,052, which Milacron filed June 20, 1989, and which was issued Oct. 29, 1991.
An abstract of the patent said it covers a molding machine with a controller, ``which includes a dedicated programmed logic controller, a real-time analog signal processor, an operator-interface station and a general-purpose, open-architecture, digital computer.'' The operator enters data on a keyboard on the operator panel.
Two representatives of companies that received the letter said there was a significant amount of ``prior art,'' when the patent first was filed — meaning other companies openly were using and marketing the technology before Milacron filed the patent. Prior art can negate a patent.
Franz Strohmaier, vice president of engineering for Engel North America, said the full text of Milacron's patent refers to a ``commercially available computer'' on the operator station.
``We do not use a `commercially available computer,''' Strohmaier said, adding that Engel does not feel it violates the Milacron patent.
He said Engel re-examined the patent four years ago, and ``we found some prior art.'' Engel notified the U.S. Patent office of its findings.
Strohmaier said Engel has responded to Milacron.
``It was a nonissue for us because, at this time, we don't have this particular configuration,'' he said.
Sandretto President Bernard Choquel said his firm received the letter and is reviewing it. Choquel said he wrote a letter back to Milacron asking Milacron not to take any action that affects Sandretto negatively until Sandretto completes its review.
According to Choquel, Milacron claims Sandretto's Mega-T and Mach III presses infringe on its patent. He said Mega-T clearly does not, because it has the same proprietary controller as Sandretto's Series 8 presses. Sandretto patent lawyers are studying Milacron's claims about the Mach III, Choquel said.
``There is so much prior art on their patent,'' Choquel said.
Michael Santa, vice president of injection molding for Krauss-Maffei in Florence, said the letter is under review.
``I think Cincinnati Milacron is a company of substance and I think it deserves its appropriate attention, but it's far too early to comment on any validity to the claim at all,'' Santa said.
Werner Christinger, president of Netstal-Machinery, said: ``We did get the letter. We have our patent attorneys looking at it.''
Van Dorn Demag confirmed it received the letter from Milacron, but the company had no additional comment.