Buren patented the first micro-rotor automatic watch movement (the Intra-matic) in 1954. They subsequently licensed the technology to companies such as Bulova and Hamilton. Universal Geneve applied for their patent in May of 1955. The microrotor movement in the Polerouter series was nearly identical in design specification to the Buren Intramatic. Buren won a patent infringement case, and U.G. had to pay Buren royalties for each microrotor it used until their patent was granted. During that early period, UG was apparently required to label their movements as "patent pending", and, as a result of the dispute, were not able to record the actual patent until May 15, 1958.
Here is some relevant detail from page 56 of the article Power or Aesthetics, by Gisbert L. Brunner (Watchtime, October, 2006):
"... Eleven months later, Universal requested patent protection for a similar construction, the so-called Polerouter. Negotiations were successful, and Universal agreed to pay Buren a reduced license fee in the amount of four Swiss francs per movement. In 1959, the two companies co-signed a licensing contract with Complications SA. Its new self-winding caliber, which was named Piaget 12Pl ..."
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