DUSSELDORF, GERMANY - K'95 offered a ringing medley of languages from around the world, but injection press shoppers heard another sound - the rumbling of patent disputes over tie-barless machines made in Austria, Germany and France. Visitors to the Dusseldorf trade show needed a scorecard to keep track of the combatants:
German machine maker Hemscheidt Maschinentechnik Schwerin GmbH & Hemscheidt Maschinentechnik Schwerin GmbH & Co. showed this tie-barless machine at K'95. Hemscheidt changed its design after a patent feud with Engel Vertriebsgesellschaft mbH.
Co. has redesigned its tie-barless machine, just a few months after its introduction, after a legal challenge from Engel Vertriebs-gesellschaft mbH of Austria. The new machine was shown for the first time at K.
French injection press maker Billion SA introduced a machine without the two upper tie bars. Shortly after the K show began Oct. 5, Billion officials announced that a prototype machine shown at Arburg GmbH + Co.'s exhibit may violate a patent to which Billion claims to have exclusive rights.
Sachsische Kunststofftechnik GmbH of Germany introduced its own tie-barless machine. So far, no one has challenged the Sachsische machine, although an Engel official said Engel was studying all competing machines in Dusseldorf.
For North American molders, the most important battle to follow will be between Engel and Hemscheidt, since both companies sell machines there. The Billion-Arburg dispute is less important in North America, at least for now, because both companies were showing prototype machines, not ones actually being produced. Plus, Billion and Sachsische do not sell actively in the United States.
Tie bars are the machined rods that link the platens together on an injection press, absorbing the clamping force and ensuring parallel platens. Making a press without tie bars was considered a breakthrough because it removed a major obstacle to access to the mold area. That allowed easier use of robots to remove parts and greater freedom in the size of a mold used in a given machine. Mold changing also is much easier.
For Engel, the stakes are huge. Engel claims to have sold several thousand machines without tie bars since introducing the technology at K'89. Engel engineers were studying all competing machines at K for possible patent violations, according to technical director Otto Urbanek.
Urbanek, at an Engel press conference Oct. 7, said the dispute with Hemscheidt probably will not be resolved before the next K show, in 1998.
Even with the redesign, Urbanek said, ``From our point of view, nothing has changed from the existing dispute.''
Hemscheidt owner Alexander Hemscheidt said: ``Today, we do not manufacture anything where we have conflicts with Engel. Today, we make a completely different design.'' The original machine was introduced in 1994 and shown for the first time in North America last June, at Plastics Fair Cleveland. It has been pulled from the market.
Making a machine without tie bars requires knowledge of mechanical engineering and physics. Engel's European patent covers a machine with jointed support of the moving platen.
Even though it is not usually necessary, Engel said, it is possible to get around the patent by adding a swivel joint to the fixed platen as well, which Engel charges that Hemscheidt did originally. Engel obtained something called a registered pattern, which is not as strong as an outright patent, to cover the two-joint design.
Engel sued Hemscheidt in a court in Mannheim, Germany.
Alexander Hemscheidt said that on the redesigned machine, the movable platen is now fixed to the frame, but a curved notch on the steel frame is designed to deform precisely without changing the platen's position. Engineers used a complex formula of physics and math to design the gracefully curving frame.
While the Engel-Hemscheidt skirmish started several months ago, K'95 was the launching point for Billion vs. Arburg. On the surface, the designs for both machines look very different-Billion's machine still retains the two lower tie bars, while Arburg's is truly ``tie barless.''
The patents on which they are based use a C-shaped frame attached by pivots to the platens.
On the Billion machine, a proprietary device using tubes is built onto the ends of the tie bars behind the fixed platen. The tubes offset forces from the top of the mold, replacing the need for tie bars, said Francois Thinard, managing director. Two lower tie bars remain.
Arburg's prototype machine has no tie bars but a similarly shaped frame, Thinard said.
Thinard said Billion's parent, Krauss-Maffei Kunststofftechnik GmbH, acquired rights to a patent filed in Europe in January 1993 by two Israeli designers. Arburg filed its patent two months later in Germany, Thinard said.
An Arburg spokeswoman denied Billion's charges of possible patent infringement.
Thinard said Billion first learned about the Arburg machine at K. Billion officials are not sure how to proceed.
``We haven't done any formal thing yet, but we have warned Arburg that we will defend our patent.'' he said.
Details were not available for the Sachsische Kunststofftechnik tie-barless machine, which is not sold in North America.
