The Diehl EVM is an electrically driven mechanical calculator with a stepped drum mechanism, a full keyboard, and which features fully automatic division and semi-automatic multiplication. It was made from 1954 until 1962. It has 18 digits in the register, and 9 digits in the counter and on the keyboard.
Most of the controls are obvious, except for the division buttons.
|← →||Move carriage left or right.|
|- +||Subtract or add the input to the register|
|. : ⋮||Clear register, counter, or input.|
|× +||Select whether to automatically clear input from keyboard. Also pauses automatic division.|
|.||Start automatic division|
|≠ .||Reverse direction of counter. Usually pressed simultaneously with division button|
|Left column||Multiply by chosen digit and shift carriage right|
|Unmarked lever||Abort automatic division|
On this version the register's carry mechanism is in the body of the machine so does not extend to any part of the carriage that sticks out to the left. In about 1956 the carry mechanism was redesigned and put in the carriage itself. Also, the division abort lever was moved next to the division buttons. My machine is therefore a relatively early one.
On the bottom is a plate showing the model and serial number. Its serial number is 26,373. In the hole near the side is a slider that releases any buttons that may have been pressed accidentally when moving the machine about.
The carriage is very easily removed. Pushing the little metal tab on top of the carriage releases a catch which allows you to pull out the rod that the carriage is attached with. When the carriage is removed, you have access to a voltage selection switch, 110 or 220 volts. It has a universal electric motor.
In a normal stepped drum mechanism there is a single sliding gear that engages with each stepped drum. The problem with that is that to select a 9 the gear has to move much further than when selecting a 1. In the Diehl the single sliding gear is replaced by two sliding gears, halving the amount of travel needed. In this way the all the number keys in a column need approximately the same small amount of force to be pressed.
Here is a video where I demonstrate the Diehl EVM.
Archimedes calculators had been produced since 1906 in Glashütte, a town in Germany, South of Dresden and close to the border with Czechia. It was a centre for the manufacturing of precision mechanics with many watch and clock manufacturers based there. Near the end of the second world war, the Archimedes factory was completely destroyed. When the war ended it was soon rebuilt, but it was located in the Russian zone. Ulrich Eichner, the son-in-law of the Archimedes founder Reinhold Pöthig, together with Wilhelm Kiel and a few other Archimedes engineers moved to West Germany, taking with them many patents and pending patents. There they developed a new machine, and negotiated with Diehl to put it into production.
Diehl was a metalworks company founded in 1902 by Heinrich Diehl and his wife Margarete in Nuremberg. It started as a small foundry and craft workshop, casting art pieces and other bespoke items, and as it grew they shifted to mass production of door knobs and fittings. In the first world war they made copper parts that other manufacturers would use to make bullet casings. Diehl would then continue to cast and press semi-finished products for other industries, for example supplying parts for the rail industry, and making pipes. In the second world war they again made ammunition, so much of their production line was destroyed, or dismantled immediately after the war.
Diehl had to rebuild its production, and not only went back to making many semi-finished products and precision parts, but also started producing clocks. When Eichler and the other Archimedes engineers came to Diehl with a calculator design it was a large and ambitious project to take on, as the proposed calculator had about 2600 precision parts. However, the Archimedes brand name was valuable and Eichner still had contacts with former Archimedes distributors who would be able to sell such a machine immediately, so this was a reasonable step for Diehl to take. After two years of development, the Diehl model A began production in 1952. By the end of the year the model B appeared, which was a more expensive model that included multiplier keys. Further similar models were developed and sold until about 1965. A 10-key listing calculator called the Diehl Transmatic, first released in 1963, soon became the more popular calculator, and variations of this were developed and sold until 1972.
Diehl tried to switch calculator production towards electronic desk calculators, but this was not so successful. The company was easily able to withstand such a setback because it was large and diverse, still making many semi-finished products, ranging from pipes and alloys to parts for white goods. The company still exists today.
Diehl made several series of stepped drum, full keyboard calculators. The series varied in the amount of extra functionality, and hence in price. Below is a table listing the various models and the functionality that they have. All models were sold in two register sizes, 8×7×15 and 9×9×18.
The functions listed in the table are:
|Input Display||An extra display register showing the keyboard input|
|Full Carry||A carry mechanism over the full length of the main register. This was introduced in 1956, and added to existing models as well.|
|Multiply||(K) Multiplier keys, (Kr) Multiplier keys with left to right entry, (A) Automatic multiplication|
|Negat Mult||Negative multiplication, i.e. the multiplier keys can subtract instead of add|
|Div Tab||Division setup and tabulation, i.e. place dividend in register with one button press, and set number of digits to calculate|
|Extra Reg||Extra storage register. Denoted by S in the model name|
|Back Trans||Back transfer from register to keyboard. Denoted by R in the model name|
Not listed in the table is automatic rounding functionality, and machines that could do this had A/A appended to their model designation. Also not listed is the EVMH, a special version of the EVM which had a detachable hand crank for use when a blackout occurs. These were especially made for the German armed forces.
In 1963 Diehl began to make a 10-key listing calculator. It was so capable that soon their other calculators were discontinued. In the US these machines were rebranded and sold by SCM (Smith Corona Marchant).
Diehl then began making electronic desk calculators, called the Combitronic and Algotronic. They used a narrow strip of punched paper tape for its internal programming, but they were not so successful as they were already outdated when they were released.
Archimedes Diehl Vom Arithmometer zum druckenden Rechensystem
Verlag W. Sünkel
208 page softcover book
210mm × 297mm × 9mm
This book details the history and mechanisms of Archimedes and Diehl calculators, with many photographs. Available from the Wehrtechnik Museum.
Here are some advertisements and articles that I found in online archives of newspapers and magazines.
Here is the list of later patents from Archimedes, which were probably licensed to Diehl and may have partly contributed to the Diehl machines.
|Patent||Filing date||Publish date||Name||Description|
|DE 651,567||10-02-1935||30-09-1937||Reinhold Pöthig||Shortcut multiplication (Model KT)
See also: CH 189,683
|DE 671,523||06-04-1935||26-01-1939||Ulrich Eichler; Reinhold Pöthig||Shortcut multiplication on electric calculation with multiplier keys (Model vM)
See also: CH 189,907 US 2,215,263
|CH 185,713||02-09-1935||15-08-1936||Reinhold Pöthig||Clear keyboard after multiplication/division (Model GEMRZ)|
|DE 691,445||22-09-1935||30-04-1940||Reinhold Pöthig||Back transfer
See also: CH 203,473
|DE 681,954||04-08-1936||14-09-1939||Reinhold Pöthig||Carriage shift buttons (Model KT)|
|DE 895,541||20-02-1937||15-06-1939||Wilhelm Kiel; Reinhold Pöthig||Simplified input for divisions (Model L)|
|DE 697,823||24-04-1937||26-09-1940||Karl Berthold Wilhelm Kiel; Reinhold Pöthig||Shortcut multiplication (Model vM)|
|DE 702,301||24-04-1937||09-01-1941||Reinhold Pöthig||Electric shortcut multiplication (Model vM)|
|DE 696,702||31-10-1937||29-08-1940||Reinhold Pöthig; Karl Otto Reinhold Henzelmann||Back transfer
See also: CH 206,225, US 2,305,780
|CH 201,329||02-02-1938||30-11-1938||Reinhold Pöthig||Motorised carriage|
|DE 696,703||23-01-1938||29-08-1940||Reinhold Pöthig||Back transfer (Model LR)
See also: CH 208,576
|DEA 86,189 AZ||18-03-1938||27-11-1941||Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Shortcut multiplication (Model vM)
See also: CH 209,385
|DE 693,890||15-04-1938||20-06-1940||Reinhold Pöthig||Back transfer|
|CH 206,224||25-04-1938||31-07-1939||Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Back transfer|
|DE 731,154||29-05-1938||31-12-1942||Karl Berthold Wilhelm Kiel; "Archimedes" Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Multiplier input
See also: CH 209,676
|DE 894,467||28-06-1938||11-02-1943||Wilhelm Kiel; Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Multiplier display (Model vM)
See also: CH 211,691
|DE 745,614||18-09-1938||16-12-1943||"Archimedes" Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Back transfer|
|DE 882,319||25-10-1938||23-10-1941||Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Clearing mechanism (Model L)
See also: CH 213,080
|DEA 88,766 AZ||12-01-1939||11-03-1943||Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Back transfer
See also: CH 214,217
|DE 919,784||21-02-1939||14-05-1942||Wilhelm Kiel; Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Motorised carriage
See also: CH 214,650
|DE 698,756||09-07-1939||17-10-1940||Karl Berthold Wilhelm Kiel; Reinhold Pöthig||Electric machine with shortcut multiplication (Model vM)
See also: CH 209,192
|CH 211,517||27-07-1939||30-09-1940||Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Motorised carriage|
|DE 749,096||13-08-1939||27-04-1944||Karl Berthold Wilhelm Kiel; Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Proportional drive
See also: CH 214,941, US 2,378,560
|CH 213,464||12-02-1940||15-02-1941||Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Back transfer|
|DE 760,102||16-07-1940||23-11-1944||Karl Berthold Wilhelm Kiel; "Archimedes" Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Disconnect during carry operation
See also: CH 222,290
|DE 746,166||02-10-1940||23-12-1943||Karl Berthold Wilhelm Kiel; "Archimedes" Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Printing calculator with motorised carriage movement
See also: CH 224,683
|DE 746,506||31-10-1940||06-01-1944||Karl Berthold Wilhelm Kiel; "Archimedes" Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Printing calculator with back transfer|
|DE 746,508||27-06-1941||06-01-1944||Karl Berthold Wilhelm Kiel; "Archimedes" Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Extended carry mechanism
See also: CH 225,815
|DE 894,467||28-06-1938||26-10-1953||Wilhelm Kiel; Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Multiplier keys with display|
|DE 895,541||20-02-1937||05-11-1953||Wilhelm Kiel; Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Motorized carriage shift|
|DE 916,475||02-02-1941||31-12-1952||Wilhelm Kiel; Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Shortcut multiplication
See also: CH 224,684
|DEA 93,422 AZ||12-05-1941||01-11-1948||Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Use of multiplier register as memory|
|DE 745,992||19-07-1939||23-12-1943||"Archimedes" Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Automatic clearing (Model L)
See also: CH 224,997
|DE 918,783||27-08-1942||10-07-1952||Karl Berthold Wilhelm Kiel; "Archimedes" Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Clearing mechanism|
|DE 919,784||21-02-1939||04-11-1954||Wilhelm Kiel; Archimedes Glashütter Rechenmaschinenfabrik Reinhold Pöthig||Motorised carriage shift|
Here are patents specifically for the Diehl calculators.
|Patent||Filing date||Publish date||Name||Description|
|DE 913,479||17-06-1951||14-06-1954||Wilhelm Kiel; Ulrich Eichler; Metall-Guß- und Preßwerk Heinrich Diehl||Carry correction
See also: CH 304,773
|DE 915,158||17-06-1951||15-06-1954||Wilhelm Kiel; Ulrich Eichler; Metall-Guß- und Preßwerk Heinrich Diehl||Carry correction
See also: CH 311,074
|DE 933,665||17-06-1951||29-09-1955||Wilhelm Kiel; Ulrich Eichler; Metall-Guß- und Preßwerk Heinrich Diehl||Key column module with display
See also: CH 305,459
|DE 973,163||21-07-1951||17-12-1959||Wilhelm Kiel; Ulrich Eichler; Fa. Diehl||Control mechanism
See also: CH 307,673, US 2,936,952
|DE 975,661||16-11-1951||12-04-1962||Wilhelm Kiel; Ulrich Eichler; Fa. Diehl||Control mechanism
See also: US 2,780,411
|US 2,969,911||08-08-1952||31-01-1961||Wilhelm K.B. Kiel; Ulrich T.R. Eichler; Metall-Guß- und Preßwerk Heinrich Diehl||Actuator and carriage control|
|DE 1,001,026||06-11-1952||17-01-1957||Wilhelm Kiel; Ulrich Eichler; Diehl GmbH||Add/subtract switching|
|DE 973,556||07-11-1952||31-03-1960||Wilhelm Kiel; Ulrich Eichler; Fa. Diehl||Plus/Mult switch|
|DE 1,094,499||04-04-1953||08-12-1960||Wilhelm Kiel; Ulrich Eichler; Diehl GmbH||Multiplier keys with shortcut multiplication|
|DE 973,882||19-04-1953||07-07-1960||Wilhelm Kiel; Ulrich Eichler; Fa. Diehl||Plus/Mult switch to interrupt division|
|DE 1,144,512||21-04-1953||28-02-1963||Wilhelm Kiel; Ulrich Eichler; Fa. Diehl||Back transfer|
|DE 1,086,465||15-05-1953||04-08-1960||Wilhelm Kiel; Ulrich Eichler; Diehl GmbH||Dividend entry and tab|
|DE 934,204||20-08-1953||13-10-1955||Wilhelm Kiel; Ulrich Eichler; Metall-Guß- und Preßwerk Heinrich Diehl||Dividend entry|
|DE 1,020,470||12-01-1954||05-12-1957||Wilhelm Kiel; Ulrich Eichler; Diehl GmbH||Extended carry mechanism|
|DE 1,027,434||09-04-1954||03-04-1958||Wilhelm Kiel; Ulrich Eichler; Diehl GmbH||-|
|DE 958,880||19-06-1954||28-02-1957||Wilhelm Kiel; Ulrich Eichler; Diehl GmbH||Drive train|
|DE 1,134,227||21-06-1954||02-08-1962||Wilhelm Kiel; Ulrich Eichler; Diehl GmbH||Automatic division|
|DE 1,157,011||26-06-1954||07-11-1963||Wilhelm Kiel; Ulrich Eichler; Fa. Diehl||Auto-aligning divisor
See also: CH 336,625, US 2,937,809.
|DE 1,023,256||10-07-1954||23-01-1958||Wilhelm Kiel; Ulrich Eichler; Diehl GmbH||Carry mechanism in register|
|DE 1,087,382||14-10-1954||18-08-1960||Wilhelm Kiel; Diehl GmbH||Multiplier keys shift lever to multiply mode|
|DE 1,695,789 U||15-01-1955||31-03-1955||Ulrich Eichler; Fa. Diehl||Key column module|
|DE 1,037,732||22-07-1955||28-08-1958||Wilhelm Kiel; Diehl GmbH||Carry mechanism|
|DE 1,108,957||26-01-1957||15-06-1961||Wilhelm Kiel; Diehl GmbH||Fully automatic multiplication|
|DE 1,135,218||26-04-1958||23-08-1962||Kurt Kollman; Fa. Diehl||Transmatic|
|DE 1,149,928||03-11-1958||06-06-1963||Gottfried Burkhardt; Fa. Diehl||Fully automatic multiplication with display|
|DE 1,667,645 U||31-07-1959||26-11-1963||Ulrich Eichler; Fa. Diehl||Multiplier keys|
© Copyright 2021 Jaap Scherphuis, mechcalc a t jaapsch d o t net.