Reumhelm

The one-stop-shop for all your checksum solutions

Theo Reumerman was born in Utrecht, The Netherlands, in 1899. In the 1930's Theo worked in the Dutch East Indies, now Indonesia. There he developed a 14-digit telegraph code in 1933 [SOE1933], a Multi-cipher-code condensor in 1934[SOE1934],  and, in 1937, a 3-letter telegraph code called "M.E.C." (Most Economical Code). This code should save 25% of the costs of the usual 5-letter telegraph code.[NAC1937] 

In 1938 he travelled to The Hague, The Netherlands, to establish a Dutch branch of his telegraph code business. Later, while living in Zandvoort, The Netherlands, he met Willem Helmig. In 1948 they presented a mechanical checksum-device, especially aimed at telephone numbers[Reumhelm1948]. At that time, Dutch local telephone numbers consisted of 5 digits. The idea was to add a sixth check-digit which was checked by the telephone itself. The telephone would block a call if the number was wrong. This local check would reduce the load of telephone exchanges without having to adapt them. Other applications were listed, like bank-note numbering, telegraphy, printing, gas meters and “general industrial use”. 

An invention[US2722378] that was actually marketed is the Controlex, a device for casting out elevens.

Controlex

Figure 1: Reumhelm Controlex [Reumhelm1953] (left) and a reconstruction (right).

Stichtse Courant 1953

Figure 2: Controlex advertisement [SC1953]

Try the interactive simulation of this device

Reumerman and Helmig also patented a device with stepped drums for checksums with arbitrary weights per digit (Figure 3) but did not restrict themselves to purely mechanical checksum devices.

They patented a checksum calculator with rotors bearing electrical contacts, conducting brushes and indicator lamps for simultaneously checking modulo 9 and modulo 11 (Figure 4).

Who sold the Controlex?

Telegraaf 8-8-1953

Left to right: Th. Reumerman, W.H.Th. Helmig J.H. Breedenbeek[Telegraaf1953]

According to the “Kantoormachinegids” [Reumhelm1953], the official seller of the Controlex was NV G. Kolff & Co, a Dutch office supplier with Indonesian roots, who was also an national importer of Monroe calculating machines[Harkink].

In 1953 and 1954, a series of small advertisements appeared mentioning “Bredenbeek, Westerscheldeplein 1, Amsterdam” as seller of the Controlex or an “American calculating aid” with the same price as the Controlex[Bredenbeek]. A 1953 newspaper article [Telegraaf1953] says that J.H. Breedenbeek(sic!) was sales officer for Reumhelm.

Did Bredenbeek sell the Controlex under his own name?


(Note: G. de Jong in Figure 2 is a local office supplier)
CA541633

Figure 3: Checksum device with arbitrary weights per digit (Canadian Patent 541,633; 1957)

US2684199

Figure 4: Checksum device with rotors, brushes and lamps (US Patent 2,684,199; 1951)

Other Reumhelm patents describe relay-based checksum calculators, a telephone-operated remote banking system (with checksums) and character-reading devices.

The name and legal status of Reumhelm SA is unclear. A 1951 advertisement mentions Reumhelm AG, established in Vaduz, Liechtenstein, but with the private address of Helmig in Leiden[AH1951]. According to a 1953 newspaper[Telegraaf1953], the company was established in Panama and Liechtenstein, and the Controlex was also sold in the USA and South Afric. Around 1955 the name “Reumhelm Electronics NV” appears. Representations existed in (at least) Switserland.

Zuse KG showed some interest in Reumhelm's inventions[Zuse], as did Remington Rand[Remington] and Landis & Gyr [ETH].

By 1953, Reumhelm held 124 patents[Telegraaf1953]. In 1955, Bell Punch Comp., Sumlock Ltd, British Tabulating Machines, Siemag, Dirks-Electronics, Zuse, Landis & Gyr, and N.V. Procento are listed as Reuhelm patent licencees[Zuse]. Some Reumhelm patents mention Remmer W. Starreveld as inventor. Starreveld was editor of the “Kantoormachinegids” and later became professor of Information Technology at the University of Amsterdam. Other names that appear on Reumhelm patents are Cornelis Adrianus Meijer and Cornelis Adrianus Simon Hamelink. 

Theo Reumerman died in 1969 [ZC1969]. Around that time Reumhelm also ceased to exist.

References