US Patent # 6,793,598 - Shimano

US Patent 6,793,598 - Shimano main image

This is less of a patent document and more of a tombstone, recording the tragic death of the dream that was EGS. Franck Savard, a very French engineer, had invented a panoply of radical bicycle transmission components, and EGS had manufactured them to exquisite standards.

But it could not last - and this document describes the inventor as Franck Savard of Osaka, Japan, and the patent rights are assigned to Shimano Inc., also of Osaka. When EGS collapsed financially, Shimano stepped in and bought various chunks of Intellectual Property - and this patent is part of that process.

Most of the content of this patent is shared with French Patent # 2,759,968. However the image on scan 11 is new - showing a different chain-tensioning spring arrangement.

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EGS Up Cage derailleur thumbnail

EGS Up Cage 1998?