Dr. Rudolf Hell (1901-2002) was one of the most important German inventors of all time. E.g., with Prof. Dieckmann  he invented the Photoelectric Image Scanning Tube (TV camera tube, patented in 1925); he invented the electronically controlled "Klischograph" half-tone photo-engraver in 1951 and revolutionized printed press technology, the first practical fax machine in 1956, a color scanner in 1963, a computerized CRT type-setter in 1965 (Datensichtgerät DS 2038, not unlike the IBM PC of the early 1980s!), and many technical processes. The renowned calligrapher and font designer Prof. Hermann Zapf (Hell Digiset fonts, standard PC fonts like Zapf-Dingbats, Palatino, etc.) rightfully referred to him as “the Edison of the Graphics Industry” and "the father of digital word processing". Hell's biographers Onnasch and Fuchs call him "Engineer of the Century". Ref. 7. He was indeed a "pioneer of teleprinting, television, fax, scanner, and printing technology" (ipse dixit).

 

In short: Hell covered all aspects of the decomposition of syllables, letter characters and images into pixels, and the processing, transmission, displaying and printing thereof. He developed the Hellschreiber during the 1920s, and in 1929 obtained a patent for his "Apparatus for the electrical transmission of text characters" ("Vorrichtung zur elektrischen Übertragung von Schriftzeichen"). Rudolf Hell explained the purpose of the Hell-Schreiber as follows (cf.  p. 2 and §10b in ref. 1):

 

Some non-German publications and websites persistently state that the word "Hellschreiber" actually means something like "bright writer", brightly writer", or worse, "bright writing".  This is brought on by mis-use of dictionaries and online translation tools. Remember: "a fool with a tool is still a fool". If anything, the Hellschreiber is the opposite of a  "bright writer": "Der Hellschreiber ist ein Dunkelschreiber!", as it prints dark on a light background. The Hell family was fortunate enough not to be living in Australia, where their surname could have caused them problems (ref. 40).

For those readers not conversant in the German language, I definitely recommend reading the one-page essay "The awful German language" by Mark Twain (ref. 55), one of my all-time favorite authors. I admire the ability of the German language to perfectly reduce an entire concept or sentence into a single word, that requires no further explanation. Nice examples of this are Wechselstromtelegraphiekurzwellenzusatz, Wehrmachtsfunkfernschreibschlüsselnetz, Streifenvorschubgeschwindigkeitsregelung, Schriftzeichenübertragungsgeschwindigkeitsregelung,  and "Wehrmachtsquarzkristallsparschaltungsnachfolger".

In 1926 and 1927 he published a number of amateur radio publications for the do-it-yourself construction of antennas and equipment, including a receiver/printer for text transmissions.

                                   
Hanns Günther and Rudolf Hell                                                Rudolf Hell                   
"Antenne und Erde", 1926.                                        "Anleitung zum Selbstbau eines
            Reprinted in 1994 by                                                  Bildempfängers", Bildfunk 1927   
Wilhelm Herbst Verlag publishing co.,                                    Die Radio-Reihe, Band 21, VIII       
336 pages, ISBN 3-923-925-54-9                                       R.C. Schmidt Verlag, 114 pages 

In his book "Bildfunk", Rudolf Hell already applied the basic concepts that he would use in the Hellschreiber a couple of years later:

"Zur Übertragung wird das Bild im Bildsender in einzelne Bildelemente zerlegt, die in Stromimpulse verwandelt werden. Der Empfänger schreibt entsprechend den ankommenden Stromimpulsen selbsttätig Punkte und Striche in richtiger Reihenfolge auf das Empfangsblatt."

"For transmission, the sender decomposes the image into individual pixels that are converted into current pulses. The receiver mechanically prints the arriving pulses as a an equivalent sequence of dots and line segments .”

 

"Die Selbstherstellung eines Funkbild-Empfangsgerätes" [build your own fax receiver-printer], Rudolf Hell, in "Funk", Wochenschrift des Funkwesens, Weidmannsche Buchhandlung, 1926, 6 pp.

The Hellschreiber is a simple and robust system that was developed specifically to provide readable, error-free communication, even on low-quality radio and land-line telephone links and in mobile applications. This made it particularly suitable for press agencies, diplomatic and military communications (incl. in combination with crypto machines), communication over high-voltage power-lines (see ref. 29, 53), and… amateur radio! It is based on raster-scan transmission of text characters , and printing the received signals as-is (no decoding required) with a helical scan mechanism. In other words: a simple form of fax, or remote dot-matrix printer. See more details on my "how it works" and "photos" pages.

Wireless services of press agencies such as the Deutsches Nachrichtenbüro (DNB), Deutsche Presse-Agentur (DPA), the Allgemeiner Deutscher Nachrichtendienst (AND), and Reuters (ref. 47), transmitted their messages in Hell-format. Reuters started its to the European continent in 1934. Broadcasting was primarily done on long-wave frequencies, to get continental coverage. Ref. 6. In the post-WWII years, agencies such as the Deutsche Allgemeine Nachrichten Agentur (DANA), Deutsche Nachrichtenagentur (DENA), the Deutsche Presse Dienst (DPD), Deutscher Sportverlag (DSV), and Telegrafnoie Agentstvo Sovetskogo Soiuza, (TASS, Telegraph Agency of the Soviet Union) also used the Hell format. TASS continued Hellschreiber broadcast at least through the mid-1950s.

Map of the wireless Hellschreiber-network of the German DNB press agency ca. 1939 (ref.  6)

The Wehrmacht is the combined army ("Heer"), navy ("Kriegsmarine"), and air force ("Luftwaffe") in Germany from 1935-1945. The Hell-system was used for military field operations. Hence, the Wehrmacht Hellschreibers are also referred to as Feldfernschreibers or Feld-Hell. They entered into service ca. 1935. In time for the start of the war (cf. p. 50 of ref. 48). The German military has operated the Hellschreiber in combination with the famous Enigma encryption system (also see ref. 31, 32, 52), e.g., for message exchanges between headquarters in European capitals (Athens/Greece-Vienna/Austria, ref. 3). Feld-Hell machines were also used by the armed forces of other countries (e.g., until ca. 1960 in Sweden). There are indications that Feld-Hell machines ("teletipo de campaña") were used by the Spanish armed forces, in particular the national army, during various conflicts: the Spanish Civil War 1936-39, World War II (a Spanish legion in the USSR), and the Ifni Wars (Spanish West Sahara and around Sidi Ifni) 1956-58. The Italian army also used Feld-Hell machines ("telescrittore campale"), see the second telegram below. The Finnish armed forces - with German supplies - used Feld-Hellschreiber in the Karelia region during the 1941-1944 "Continuation War" against Russia.

The Luftwaffe also used Hellschreiber technology for aerial navigation, as part of the "Berhard" system. The ground-station transmitted the momentary azimuth of its narrow-beam antenna in Hell format on VHF (30-33.3 MHz), as the antenna rotated (ref. 3). Its airborne counterpart is a small Hell-printer, the FuG 120 "Bernhardine" ("UKW-Richtstrahl-Drehfunkfeuer Empfänger" or "Receiver for VHF rotational directional beam beacon". It was installed in various aircraft types, esp. night fighter versions, such as the Messerschmitt Me262 (one of my all time favorite aircraft), Junkers Ju 88G, Arado Ar234 (ref. 4), and Dornier Do-335.

In 1944 the Hell Co. developed the "Hell-Geheimschreiber" encryption machine. It used 2³⁵ possible codes for each 7x5 dot character, using a one-time-pad encryption algorithm with a period of 10¹⁴ (see ref. 5). Apparently only half dozen or so of these machines were ever made. They were used in U-Boot, and on Kriegsmarine ships in the Mediterranean in 1945. The Hell Co. resumed the design and manufacture of crypto systems in the 1950s. Commercial use of Hell-systems continued well into the 1980s.

LIFE

Rudolf Hell was born on 19 December 1901 at the local freight railway station of Eggmühl (Lower Bavaria, 15 km south of Regensburg, 90 km northeast of Munich) where his father, Karl Hell, was station master for the Königlich-Bayrische Eisenbahngesellschaft (Royal Bavarian Railway Co.). It is here were Rudolf was exposed to telegraphy at an early age. His mother, Lidwina, was the daughter of a farmer and beerbrewer. Rudolf had two older brothers, Karl and Max. The area was a battlefield in 1809, when Napoleon's army defeated the Austrian army under Archduke Karl.

Karl, Max, and Rudolf (left to right) - 1919
(courtesy C. Onnasch and B. Fuchs, ref. 6, used with permission)

At the age of six, his father was transferred some 160 km (100 mi) north to the freight station in the town of Eger, then in the Austro-Hungarian empire - now a border-town in the Czech Republic and named "Cheb" since 1945. This is where he attended elementary school for four years. He was a bit of an outsider and didn't hang out with the kids in the street. Apparently he had a pale complexion. Attempts were made to strengthen him, and bring color to his cheeks with red wine.

The railway station of Eggmuehl ca. 1900 - father Hell (station master) at far left
(courtesy C. Onnasch and B. Fuchs, ref. 6, used with permission)

After finishing elementary school, he went to the Rudolphinium Oberrealschule (a form of secondary school). It was not named after young Rudolf, but in honor of King Rudolph I of Habsburg. Rudolf graduated in 1919. He was good at physics and math, mediocre at languages, and was poor at subjects that didn't interest him.

At the age of 18, he went to the Technische Hochschule München (Technical University in Munich) where he obtained his "Diplom-Ingenieur - Elektrotechnik" (Dipl.-Ing.) degree in 1923 (Master's Degree in Electrical Engineering). This is where he met Prof. Max Dieckmann (ref. 43), who lectured on wireless telegraphy and was forced to rename his lecture "wireless television" to something less provocative. Dieckmann was already involved with scanning of text characters, converting them into electrical pulses and displaying them on a cathode ray tube (CRT), see ref. 44a, b, c. The CRT was invented in 1895 by Nobel Prize laureate Karl Ferdinand Braun, and is still referred to as "Braunsche Röhre" ("Braun Tube") in German speaking countries and in Japan today. Dieckman was Braun's assistant 1905-1906. In 1925, Hell filed his first patent (with Dieckmann): an image decomposition tube ("Bildzerlegerröhre"), a simple video camera tube.

In 1927 Hell obtained his doctorate degree with a dissertation on "a direct indicating radio direction finder for aviation", which became the basis for automatic guidance and auto-pilots of aircraft. The invention was licensed to Telefunken and to a US company for a tidy sum.

"Direktzeigendes funkentelegraphisches Peilverfahren", Rudolf Hell, 1929, 10 pp., Krayn Verlag, Berlin, Hochschulschrift, 1928 doctoral dissertation at Technische Hochschule München; Also appeared in: "Jahrbuch der drahtlosen Telegraphie".

 

In the late 1920, Hell considered the TV technology to be in an impasse, and switched over to facsimile. At the very beginning of 1929 (at the age of 28) he and his wife Martha moved to Berlin-Babelsberg, and had a furnished room in the house of an employee of the Auto-Union (a combination of the automobile and motorcycle companies DKW, Horch, Audi ("Horch" in Latin, and Wanderer).  Shortly thereafter, he bought a house at Ihnestraße 41 in Berlin-Dahlem.  This is where the Dr.-Ing. Rudolf Hell Company was founded. The machine shop was in the basement, the design office and lab on the ground floor, the office in the hallway, and private quarters upstairs. Hell worked here with about a dozen  dozen employees.

Rudolf Hell bought his first house in Berlin-Dahlem
(courtesy C. Onnasch and B. Fuchs, ref. 7, used with permission)

His patent entitled "Device for the electrical transmission of text characters" (nr. 540849, see table below) represents the birth of the "Bildschreiber" (i.e., "image writer"). It was later named "Hell-Schreiber", after its inventor. This has  turned out to be one of the turning points in telecommunication. The basic idea of decomposing graphical information into pixels and lines that are easy to process (generate, transmit, reconstitute) has been the theme of Hell's life work. He developed the Hellschreiber in 1929, and that same year he licensed the rights to the Siemens-Halske (S-H) company for 13,000 Reichsmark (the currency in Germany from 1924-1948) - estimated (by me) to be equivalent to half a million US dollars (2008). His first customer was the German railway company. The house in Berlin-Dahlem was paid for with this money, plus the proceeds of the sale of his car, and a 3000 Mark inheritance from his mother. Ref. 49.  In 1931 the company moved to larger facilities in Berlin-Dahlem,  and again in 1937 - to facilities at Kronprinzenallee 138 in Berlin-Zehlendorf, a couple of streets away from the Ihnestraße.

 

Hell Werke in Berlin-Zehlendorf  (source: ref. 38)
 

Below is are listings for Rudolf Hell, from the telephone book of Berlin. Starting in 1937, he is listed as "Fernmeldetechnisches Institut": Telecommunications Institute.

 

Phonebook entries for Rudolf Hell (top to bottom: 1934-1943)
(source: Berliner Adressbücher 1799-1943, telephone & address books of Berlin)

 

During the latter half of the 1930s, the Hell company had the radio callsign D2bw. This was an experimental license. Transmitter location, max output power, frequency bands (incl. amateur radio bands), modulation (telegraphy/phone) and purpose were fixed. Communication with other licensees was typically not allowed. The license of 1938 indicates the permission to use Hellschreiber telegraphy with 100 watt, for the development of telemetry systems and radio communication systems, per instructions of the Wehrmacht and other government organizations.

 

Entry in the 1935 radio license list

(source: ref. 61a)

 

Entry in the 1938 radio license list

(source: ref. 61b)

 

Rudolf Hell as a private person did not hold a private license. He does not appear on the 1936, 1937, or 1939 list of "Liebhaberfunker" (radio amateurs), nor on the 1944 (short) list of "Kriegsfunkgenehmigungsinhaber" (war-time licensees). Ref. 61a/b/c. In 1926, he did co-author a hefty book about amateur radio antennas (ref. 63).

 

In Germany, the first broadcast radio station started transmissions in October of 1923 (Berlin). The only radios allowed were those with a registration-stamp of the Reichstelegraphen-Verwaltung (Imperial Telegraphy Administration), part of the Deutsche Reichspost. Starting mid-May of 1924, private individuals could obtain a permit for owning and operating a receiver station ("Audion-Versuchserlaubnis"). This required passing of a knowledge test, administered by a radio club. From November of 1924 on, transmitter licenses were issued to radio clubs, corporate development labs, and technical universities - not to private individuals. Late August 1925, the Reichspost lifted the ban on the private construction of radio receivers. Amateur transmission were relegated to "pirate" transmissions with fictitious callsigns. The Fernmeldeanlagegesetz (Telecom Equipment Law) of 1928 made operation of all telephone, telegraph, teleprinter, and radio equipment subject to a (paid) regsitration license. The callsign prefix "D" became effective in Germany on 1 January 1929. Decrees of the Reichspost Ministerium in 1930 and 1931 made connecting a transmitter to antenna illegal. The national-socialist regime came to power early 1933 and initially tried to dissolve the national amateur radio organization (DASD). In 1937, illegal transmissions became an offense, punishable with a prison sentence. Shortly after the beginning of WW2 in 1939, amateur radio was generally banned. However, a "Kriegsfunkgenehmigung" (war-time license) were issued to a small number of members of the Wehrmacht (e.g., about 150 in 1944, ref. 61c). Log books had to be sent to the DASD (controlled by Mr. Goebbels' ministry) on a regular basis. Also see ref. 63 and 64.

 

During the 1930s through 1945, the S-H company built large numbers (an estimated 50 thousand) of "Presse Hell" machines (for news agencies, etc.). According to Dr. Hell himself (ref. 6), the invention was a "Aha-Erlebnis" (a.k.a. "eureka moment"; the Greek εύρηκα roughly translates to "I have found it"), much more than the result of tedious research and development.

Figure 2 of the 1929 Hell patent

Hell continued the development of Hellschreibers. Hell, like the entire industrial complex, was obliged to support the war effort. This included the development of Morse telegraphy (training) devices, metal detectors, fuses for mines, radio direction finders, formation-flying flight-guidance systems. As a subcontractor to the C. Lorenz company, Hell developed and manufactured the UKE 5 and UKE 7 modules of the remote control and guidance receivers of the V2-missile (ref. 37). He was also involved with the development of crypto machines. At the end of the war, he had about 1000 employees in his two factories. All was lost by the end of the war, and he started all over again in 1947 (ref. 57). This time in Kiel (port city in the far north of Germany).

First Hell Werke in Kiel (source: ref. 38)

Dr. Hell with a Hell tape printer for press services
(courtesy C. Onnasch and B. Fuchs, ref. 6, used with permission)

Around that same time, an engineer at Sony in Japan reverse-engineered the Hellschreiber, and Sony manufactured 10 to 20 machines (ref. 9; photo and description is here). Early 1948, Siemens-Halske handed off their image transmission activities to Dr. Hell, with a 30-year contract. In 1956 he developed and produced the first practical fax machine (Kleinfaxgerät KF108; ref. 59). The received binary image is printed directly onto normal (!) paper with an inked saffire-wheel, rather than by passing electrical current through impregnated paper (e.g., potassium ferro-cyanide or potassium iodide). Some twenty years later, Japanese companies very successfully revived it...

Kleinfaxgerät "KF108d" for DIN-A5 paper size
(with Siemens label, but developed and manufactured (1953-1958) by Hell GmbH)

Hell also revolutionized pre-press processing for printed media (newspapers, magazines, etc.) by developing the fast and precise Klischograph. This provided one-step operation of image scan/transfer and engraving of printing blocks and plates (later expanded for color images). The color Klischograph reduced the time required to generate a single set of A4 size plates from one week, to four sets in one day! In 1963, he invented the Chromagraph color scanner that provided 4-color separation. Ref. 50. He also revolutionized film scanning (exposure) technology, and the developed the first electronic type setting machine in 1964. It had a digital magnetic core "font" memory and CRT-projection onto film. In 1968, the "DS" (Datensichtgerät) was the first computer (Siemens, of course) with a keyboard, CRT, and text editing software. Corporate management, in its usual "wisdom", declared this a dead-end technology and it was subsequently abandoned. The "DS" remained unsurpassed for 15 years, until IBM popularized a similar product in 1983: the PC.

 

The Dr.-Ing. Rudolf Hell & Co. KG (KG = Kommanditgesellschaft) company was converted into Dr.-Ing. Rudolf Hell GmbH in 1971, when Siemens AG increased its 49% minority share in the company to an 80% majority share (increased to 100% in 1981). In 1990, Dr.-Ing. Rudolf Hell GmbH merged with Linotype AG. The Heidelberger Druckmaschinen AG acquired Linotype-Hell AG in 1995.

 

Rudolf Hell in 1977
 

In 1978, Dr. Hell was awarded the prestigious Werner-von-Siemens-Ring for achievements in science and technology (ref. 49). He retired from active business activities in 1990.

 

On 11 March 2002, this pioneer of telecommunication passed away in Kiel, at the age of 100...

 

Logo on the dinnerware of the Hell Co. in Kiel

 

 

Commemorative post card from the 2005 "National Stamp Day"

 

VIDEOS AND AUDIO INTERVIEWS

 

VIDEO:

50 sec video clip of Rudolf Hell at a party in his honor

(double-click image to start/pause, or click here to start your own player)

 

AUDIO INTERVIEWS with Rudolf Hell (in his native language):

Rudolf Hell about his time in Berlin; 22 sec; © C. Onnasch (use player controls below, or click here to start your own player):

         

Rudolf Hell about his work with Prof. Dieckmann; 52 sec (use player controls below, or click here to start your own player):

         

Rudolf Hell about the Hellschreiber; 26 sec (use player controls below, or click here to start your own player):

         

Rudolf Hell about his results in school ("Zeugnis"); 10 sec (use player controls below, or click here to start your own player):

         

Rudolf Hell about the Klischograph; 1 min 27 sec (use player controls below, or click here to start your own player):

         

 

AUDIO DOCUMENTARY:        

30-minute radio documentary about Rudolf Hell (in German; "Bayern 2" radio, "Wort" program, 6-January-2002): (use player controls below, or click here to start your own player):

         

 

PATENTS

The table below lists a selection of patents that list Rudolf Hell as the inventor, and are related to various aspects of Hellschreibers. Worldwide, he is listed as (co-)inventor on nearly 1000 patents. Patents most closely related to the basic principles of Hellschreibers have been highlighted with bold face font. Scanned copies of the original patents are available by clicking on the respective patent number. The table lists the publication date of the patent award. Application for the patent may have been filed several (sometimes many) years prior to the actual award. Also, the date from which the patent rights apply may be different from the filing and the publication date. See the actual patents for details. 

Patent number	Patent office	Filing date	Inventor(s)	Patent owner(s)	Title (original)	Title (translated)
450187	DE	5 Apr. 1925	Dr. Max Dieckmann, Dipl.-Ing. Rudolf Hell	Dr. Max Dieckmann, Dipl.-Ing. Rudolf Hell	Lichtelektrische Bildzerlegerröhre für Fernseher	Photo-electric image-decomposition ("dissector") tube for television
469012	RP	28 Nov. 1926	Dr. Max Dieckmann, Dipl.-Ing. Rudolf Hell	Dr. Max Dieckmann, Dipl.-Ing. Rudolf Hell	Verfahren zur Gleichtrittregelung von Bildwalzen nach dem d'Arlincourtschen Prinzip	Method for synchronization of image drums, based on a noise-insensitive adaptation of the d'Arlincourt principle
540849	DE	3.APR.1929	Dr.-Ing. Rudolf Hell	Dr.-Ing. Rudolf Hell	Vorrichtung zur elektrischer Übertragung von Schriftzeichen	Device for the electrical transmission of text characters
541935 addendum to 540894	DE	17.SEPT.1930	Dipl.-Ing. Dr.-Ing. Rudolf Hell	Dipl.-Ing. Dr.-Ing. Rudolf Hell	Vorrichtung zur elektrischer Übertragung von Schriftzeichen	Device for the electrical transmission of text characters
668821	DE	4 Aug. 1933	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Empfangsanordnung für die Übertragung von Schriftzeichen	Receiving device for the transmission of text characters
658527	DE	12 Aug. 1933	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Anordnung zur Gleichlaufregelung von Telegraphengeräten, welche Schriftzeichen in Bildpunkte zerlegt zeilenmäßig aufzeichnen	Arrangement for synchronization of telegraph apparatus print columns of text characters decomposed into pixels
699712	DE	12 Aug. 1933	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Anordnung zur Gleichlaufregelung von Telegrafiegeräten, bei denen die Schriftzeichen in Bildpunkte zerlegt aufgezeichnet werden	Device for the synchronization of telegraphy machines that print text characters decomposed into pixels  [addition to patent 658527]
2113429	US	11 Aug, 1934	Rudolf Hell	Siemens & Halske AG	-	Arrangement for synchronizing of telegraph apparatus
146320	OE	2 Aug. 1934	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Verfahren und Anordnung zur Gleichlaufregelung von Telegraphenapparaten.	Method and device for synchronization of telegraph apparatus
683628	DE	27 Feb. 1936	Dr.-Ing. Rudolf Hell	Dr.-Ing. Rudolf Hell	Druckhammer für Bildübertragungsgeräte und Fernschreiber	Print hammer for image transmitting devices and tele-writers
150113	OE	15 July 1936	Dr.-Ing. Rudolf Hell, Dipl-Ing. Horst Rassow	Siemens & Halske AG	Sendeeinrichtung für Faksimiletelegraphen.	Sending device for facsimile telegraphs
668102	DE	9 Aug. 1936	Dr.-Ing. Rudolf Hell	Dr.-Ing. Rudolf Hell	Schreibsystem zur Registrierung von Morsezeichen, Schriftzeichen und Bildpunkten	Printing system for Morse characters, text characters and pixels
155198	AT	2 Feb. 1937	Max Dreßler, Dr.-Ing. Rudolf Hell, Dipl-Ing. Horst Rassow, Willy Skawran	Siemens & Halske AG	Verfahren und Vorrichtung zur Synchronisierung von Bildübertragungsgeräten, Ferndruckern und Fernschreibern	Method and device for synchronization of image transmitting devices, tele-printers and tele-writers
757304	RP	13.APR.1939	Dr.-Ing. Rudolf Hell	Dr.-Ing. Rudolf Hell	Anordnung zur Herstellung des Gleichlaufs von Fernschreibern	Device for establishing synchronization of tele-writers
694437	DE	13 Aug. 1937	Dipl.-Ing. Dr.-Ing. Rudolf Hell	Dipl.-Ing. Dr.-Ing. Rudolf Hell	Schreiber für Morsezeichen und Bildtelegrafenimpulse	Printer for Morse characters and image telegraphy pulses
707536	DE	19 Jan. 1938	Dr.-Ing. Rudolf Hell	Dr.-Ing. Rudolf Hell	Verfahren zur Übertragung von Schriftzeichen, die in Bildpunkte aufgelöst auf einer Sendewalze aufgetragen sind	Metod for transmission of text characters tat are decomposed into pixels and arranged onto a sending drum
739880	DE	12 Mar. 1939	Dr.-Ing. Rudolf Hell, Walter Ay	Dr.-Ing. Rudolf Hell	Anordnung für Fernschreiber mit Start-Stop-Betrieb	Device for tele-writer with Start-Stop operation
2335410	US	23 Nov. 1940	Rudolf Hell	Rudolf Hell	Method of transmitting characters by means of revolving drums	[very similar to patent nr. 7075369]
2356584	US	23 Nov. 1940	Rudolf Hell	Rudolf Hell	Recording spindle	-
832444	BD	15 Mar. 1949	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Verfahren zur Übertragung von Schriftzeichen nach dem Hell-System mittels Blattschreiber	Method for the transmission of characters with a page/sheet printer, per the Hell system
838322	BD	2 July 1949	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Verfahren zur Übertragung von Schriftzeichen	Method for the transmission of characters [page/sheet printer]
803577	BP	21 May 1949	Dr.-Ing. Rudolf Hell	Dr.-Ing. Rudolf Hell	Elektrischer Fliehkraftregler	Electrical centrifugal governor
816422	BD	14 Dez. 1948	Dr.-Ing. Rudolf Hell	Dr.-Ing. Rudolf Hell	Anordnung zum Anlassen und Anhalten von Hellschreibern und ähnlichen Telegraphiegeräten	Device for starting and stopping of Hellschreibers and similar telegraphy machines [remote control]
825277	BD	24 Dec. 1948	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Blattschreiber nach dem System des Hellschreibers	Hellschreiber sheet/page printer
838765	BD	15 Mar. 1949	Dr.-Ing. Rudolf Hell, Dipl.-Ing. Heinz Taudt	Siemens & Halske AG	Verfahren und Einrichtung zur Gleichlaufregelung von Empfangsanordnungen für Schriftzeichen-Übertragung nach dem Hell-System	Method and device for the synchronization of receivers for character transmission per the Hell system
847024	BD	3 Apr. 1949	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Blattschreiber für die Aufzeichnung von Schriftzeichen	Page/sheet printer for the recording of characters
851826	BD	15 Mar. 1949	Dr.-Ing. Rudolf Hell, Dipl.-Ing. Heinz Taudt	Siemens & Halske AG	Einrichtung zur Gleichlaufregelung von Empfangsanordnungen für Schriftzeichen nach dem Hell-System	Device for the synchronization of receivers for character transmission per the Hell system
856605	BD	22 Jan. 1950	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Anordnung für Fernschreiber mit Kontaktwalzen, bei denen durch Druck einer Taste eine Sperrvorrichtung betätigt wird	Arrangement for teleprinters with contact-drum, in which a lock-out mechanism is engaged when a key is pushed
848970	BD	21 Dec. 1948	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Blattschreiber für Hellempfang	Sheet/page printer for Hell reception
856606	BD	22 Jan. 1950	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Verfahren und Einrichtung zur Synchronisierung von Hell-Schreibern	Method and device for he synchronization of Hellschreibers [using separate pulses]
863358	BD	3 Nov. 1949	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Verfahren und Einrichtung zum Synchronisieren der Sende- und Empfangsanlage für Schriftzeichenübertragungen nach einem Abtastverfahren	Method and device for the synchronization of sending and receiving equipment for the transmission of characters using a scanning method [optical]
866052	BD	2 Oct. 1948	Dr.-Ing. Rudolf Hell	Siemens & Halske AG	Blattschreiber nach dem Hell-System	Page/sheet printer according to the Hell-system
9699210	DP	29 Apr. 1949	Dr.-Ing. Rudolf Hell	Fa. Dr.-Ing. Rudolf Hell	Vorrichtung zum Aussenden von in Bildelemente zerlegten Schriftzeichen nach dem Hell-System mittels Impulsfolgen	Device for the transmission with pulse sequences of characters that have been decomposed into pixels per the Hell-system.
290749	CH	1 July 1949	-	Siemens-Halske AG	Verfahren und Anordnung zur Übertragung von Schriftzeichen.	Method and system for the transmission of characters
880318	BD	9 Aug. 1949	Dr.-Ing. Rudolf Hell, Dr.-Ing. Rudolf Zimmermann	Siemens & Halske AG	Verfahren zur Übertragung von Schriftzeichen nach dem Hell-System	Method for transmission of text characters with the Hell-system
2658106	US	27 June 1950	Rudolf Hell	Siemens & Halske AG	Facsimile Printing Telegraph System
2731322	US	14 Dec. 1950	Rudolf Hell	Rudolf Hell	Recording devices	[variants of spindle and paper tape]
939159	BD	16 Mar. 1955	Dr.-Ing. Rudolf Hell	Fa. Dr.-Ing. Rudolf Hell	Verfahren zur Übertragung von mit einer Schreibmaschine auf einen bandförmigen Schriftträger gedruckten Schriftzeichen durch photoelektrische Abtastung der Schriftzeichen nach dem Hell-System	Method for the transmission of characters printed onto tape medium, with photoelectrical scanning of the characters per the Hell system
2853551	US	8 Aug. 1956	Rudolf Hell	Dr.-Ing. Rudolf Hell KG	-	Page printer facsimile receiver
378940	CH	27 Nov. 1959	Dr.-Ing. Rudolf Hell	Fa. Dr.-Ing. Rudolf Hell	Verfahren und Vorrichtung zur Übertragung von Schriftzeichen, die entsprechend dem Hell-Code oder einem diesem ähnlichen Code in Bildelemente zerlegt sind, und zu deren Aufzeichnung mittels Blattschreibers im Faksimileverfahren	Method and device for the transmission of characters that have been decomposed into pixels per the Hell-code or similar code, and for their recording with a facsimile method on a page/sheet printer

 

Patent office abbreviations:

OE = Österreichisches Patentamt
AT = Deutsches Reich, Reichspatentamt, Zweigstelle Österreich
DE = Deutsches Reich, Reichspatentamt
RP = Reichspatentamt
DP = Deutsches Patentamt
BD = Bundesrepublik Deutschland, Deutsches Patentamt
US = United States Patent Office

CH = Swiss Patent Office (Schweizerische Eidgenossenschaft - Eidgenossisches Amt für geistiges Eigentum)

Patent sources:

DEPATISnet, the on-line public database of the Deutsches Patent- und Markenamt (DPMA, German Patent and Trademark Office)
PATFT, the on-line public database of the United States Patent and Trademark Office

Interesting development and patent activities in this same area are by Ernst Eduard Kleinschmidt, a German-born US immigrant. During the period 1915-1920 he developed electromechanical printing telegraphs with Charles Krum. Their improved synchronization method was used in the "Springschreiber" ("start-stop teleprinter"). It was licensed to the C. Lorenz company of Berlin-Tempelhof in 1926, and equipment was sold directly to the Deutsche Reichspost that same year. Siemens-Halske developed similar machines that avoided that Kleinschmidt patent (e.g., Blattschreiber "T typ 37"), as did the Creed Co. in the UK.

The Kleinschmidt patent listed below was filed August 1930, well after Hell's original patent filed April 1929. It also includes a double-helix printer spindle and a (notched) character code drum, though the construction is more complex. Kleinschmidt is behind the development of Teletype Corp. Model 17 teleprinter, which appears functionally to be a copy of the Hell Feldfernschreiber.