Professional Jeweler Archive: U.S. Watchmaker Develops ‘Eternal’ Power

February 2003


U.S. Watchmaker Develops 'Eternal' Power

Look for premier watches at Basel 2003

Watchmaker Steven Phillips has patented a mechanical watch power supply that requires only small temperature changes to remain in continual operation.
The power system, the first of its kind for mechanical watches, is called Eternal Winding System and is now installed in several watches made at Phillips’ company, Budapest Watch Co., Guilford, CT.

Under development since early 2000 and granted a worldwide patent late last year, it’s the first fully mechanical wristwatch that requires neither winding nor wearing to operate. Several Japanese companies offer watches that use temperature variations to operate quartz movements, but Phillips says he’s the first to develop the technology for a mechanical movement.

Bimetallic Coil

Similar to a mechanical thermostat, where a metal coil expands and contracts as air temperature changes, Phillips developed a bimetallic coil with proprietary components so sensitive they expand or contract at the slightest temperature variation. The movement of this coil as it expands or contracts is transferred to a mainspring, the heart of a mechanical watch. Phillips’ versions use this coil to drive gears that move the hands and other indicators.

Because there’s no stopping the power, this timekeeping system is well-suited to perpetual watches,” says Phillips, who makes the watches by hand. Three versions are under way:

  • A direct-drive mechanism for rugged applications.
  • A “double-planetary” mechanism that allows for more applications in the final product.
  • One with an additional gear system on top of the double-planetary mechanism for advanced complications.

Phillips says the first watches using the new technology, cased in gold, will premier at Basel 2003, April 3-10. The direct-drive version, his most basic, is $64,200 retail. The others are $79,000 and $109,000. By December, seven watches had been ordered already.

Phillips will make a limited number by hand until he licenses the patent to other companies. Technical details, including a link to the patent, can be found at

• Budapest Watch Co., Guilford, MA; (877) 498-0653.

– by Michael Thompson

Here’s a prototype watch showing the planetary gear mechanism in a watch that uses Steven Phillips’ Eternal Winding System. Phillips is the only U.S. member of the Academie des Horological Createures Independents.
The reactive coil (left) powers the winding system. A temperature change of one degree higher or one degree lower (or two degrees either way) powers the gears. At center is the direct-drive wheel used in one version of the watch. At the right is a planetary gear module for the most complex version.

Copyright © 2003 by Bond Communications