Germany is known for both its innovative engineering and its sausages, so the technical leap could seem almost inevitable. But it was the high hurdles put up by the city’s bureaucracy that fathered the invention of these unusual contraptions that are now as much a part of the city’s sights as the television tower in Alexanderplatz or the cathedral, outside of which Grillwalkers also hock their sausages.

Image A Grillwalker, with a canister of flammable propane strapped to his back, sold bratwurst for $1.75 at the Berlin Alexanderplatz. Credit... Oliver Hartung for The New York Times

After losing his job in hotel management in 1997, Bertram Rohloff wanted to open a stand to sell sandwiches, but found he could not get the necessary permits to set up shop. So instead he envisaged an evolution in food-preparation technology, a step beyond the rolling hot-dog cart, because without the necessary permits, neither the grill nor the sausages could touch the ground.

“You couldn’t get an A-1 location like Alexanderplatz for all the money in the world,” Mr. Rohloff said in an interview recently in the company’s home base in the Friedrichshain neighborhood in the former eastern part of the city. And the salesmen’s mobility allows them to follow the crowds, with Grillwalkers popping up outside nightclubs on busy evenings, at major parades and even at union demonstrations, which Mr. Rohloff said were among the best places for business.

As he worked on the invention, Mr. Rohloff considered everything from burning charcoal to hooking the grill up to a car battery  which he rejected because it would run down in just 10 minutes  before settling on propane. He designed it with an automatic cut-off mechanism for the gas, to ensure that it was safe in the event of an accident.

Mr. Rohloff was the first person to don his invention and sell bratwurst on the street. He now has 15 employees selling sausages around the city in teams of two; they take turns wearing the grill and reloading the sausages, rolls and condiments.

But his ambitions extend far beyond the German capital, and the 17 to 30 cents in profit made on each sausage. In all, the company has built 73 Grillwalkers, including the newest one, which sits in his office, sharing space with towers of jumbo buckets of mustard stacked against the wall. He has subcontractors renting them in cities around the country, from Hanover to Karlsruhe.

And Mr. Rohloff has sold the equipment, at $7,100 a piece, to customers in Bulgaria, Colombia, South Korea and elsewhere, including one to a man in Nebraska. Just this week he sold one to a client in South Africa, which next year will host the World Cup soccer tournament.