Vintage Info – All About Vintage Lighting

Cosack Swing-Arm Diabolo Wall Lamp

Materials: Articulating brass rods and parts. Off-white/beige painted diabolo lampshade, painted with wrinkle-paint. White painted inside. Some metal parts, Metal socket. 

Arm: 100 cm / 39.37”

Height: 28 cm / 11.02”

Width: ∅ 31 cm / 12.20”

Electricity: 1 bulb E27, 1 x 75 watt maximum, 110/220 volt.
Any type of light bulb can be used, not a specific one preferred.

Period: 1950s, 1960s – Mid-Century Modern.

Designer: To be appraised.

Manufacturer: Gebrüder Cosack – Gecos, Neheim-Hüsten, Germany.

Other versions: Made in several colours. A version with a different arm was also made, as you can see below and in the photo of the German film Lola from 1981. The lampshade was also used for a pendant lamp and a table lamp.

Often attributed to Louis Kalff, but that is not trueLouis Kalff designed several lamps with a similar lampshade for Koninklijke Philips, the company he worked for all his life, but that’s all.


The Gebrüder Cosack (Gecoscompany was founded in 1848 as a metal processing plant in Neheim-HüstenGermany by Egon, Friedrich and Theodor Cosack. In the beginning they made liturgical items and crosses made of brass and they also produced kerosene lamps. Later the company came to the production of electric lamps.

After the Second World War Cosack pursued a modern direction. A best seller were copper lighting for restaurants. The company was declared bankrupt in 1984.

Best known designers: Ursula or Gottfried Stürzenhofecker (unclear, they are both designers), K. H. Kinsky.

Gebrüder Cosack (Gecos) received 15 iF Design Awards


Diabolo is the name given to the shape of the lampshade. The diabolo lampshades were very popular in the 1950s. You can find several examples on Vintageinfo.

The diabolo, some yo-yo, has its origin in China. It’s a double-coned bobbin that can be twirled, tossed, and caught on a string secured by two sticks, one held in each hand. The first diabolo’s were made of bamboo and they made some whistling sound.

In the eighteenth century, the diabolo became known in England and France. The term “diabolo” was made up by French engineer Gustave Phillippart, who developed the modern diabolo in the early twentieth century and he was re-released. Since then, he has been widespread.

Gebruder Cosack Wall Lamp