In 1935, he signed an agreement for manufacturing a new theodolite with Kern Aarau, Switzerland. After Heinrich Wild separated from Wild Heerbrugg in 1935, he presented his newest theodolite designs to Kern for manufacturing purposes and a completely new line of theodolites was created.

His new designs were introduced to the geodetic community for the first time at the International Congress of Surveyors in Rome in 1938. The instruments shown were the theodolites without optical micrometer DK1 and DK2 as well as the types with optical micrometer DKM1, DKM2 and DKM3.

All these instruments had several new features in common: Leveling cams which turn on a horizontal axis for precise leveling, very stable, high precision ball bearing vertical axis, glass circles with two concentric graduations (double circle principle), powerful, short telescopes, fully transitable, an overall very compact and rugged lightweight design

Source: http://homepage.hispeed.ch/dedual/wild_heerbrugg/hwatkern.htm