Source: https://www.flickr.com.License: All Rights Reserved.

Established in 1935, Altenburger GB was first a manufacturer of bicycle rims, then brakes and derailleurs. Founder Karl Altenburger, was successful pro racer in his earlier years. Located in Jestetten, Germany, this company is now the producer of electronic controls. — Classic Rendezvous

The brakes shown in these photos are probably 1970s, but the logo appears to go back to near the company's founding. This use of a typeface for a badge is unusual because it comes from the pre-digital era when it was much more common to use lettering (not type) onSignalwith the romanized alternate 'r'. "Synchron" feels lettered to me, but it could be one of many broad Grotesques from the early to mid 1900s.

Source: https://www.flickr.com.Photo by Tom Thistlethwaite. License: All Rights Reserved.

Source: https://www.flickr.com.Photo by "headgasket13" on Flickr. License: All Rights Reserved.

"If The Internet is to be believed, Altenburger Synchron brakes like these were among the earliest — if not the very first — dual-pivot sidepulls available on mass-produced bikes. They are easier to set, adjust, and maintain than comparable single-pivot sidepull brakes." — headgasket13