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Hamann / DeTeWe

Hamann Manus E

The Hamann Manus looks like a pinwheel calculator, but it uses a different mechanism. At the front is a carriage containing a 13-digit main register on the right and an 8-digit counter on the left. In the main body are 9 input levers with an input register that displays the current lever settings. There is a large crank on the right, and a clockwise turn of that crank normally adds the input to the register, and increments the counter. There is a switch to the left of the input that changes the direction of the counter.

The main noticable difference from a normal pinwhweel machine is that the crank cannot be turned anti-clockwise. To subtract you must instead flick a switch located below the crank to set the machine in subtraction mode. This shifts the carriage a half step, thereby reconnecting the carriage register through a set of intermediate gears. A clockwise turn of the crank then subtracts the number because it turns the register digits in the opposite direction. There is a very small tab just below the counter direction switch with which the crank can be reversed. If for some reason the mechanism locks up and the crank cannot move forward, then you can push the tab to allow the crank to move backwards into its cradle so that the problem can be fixed more easily.

The carriage can be moved a step left or right using the arrow buttons next to the crank, or any amount using the knob on the front of the carriage. The clearing levers for the register and counter are on the two ends of the carriage. The input can be cleared with the round button on top of the machine. When the button is pressed, the input pins spring up to zero. If the button is rotated so that its arrow points to the left, then the button is pushed down with every turn of the crank so that the input is cleared automatically after each addition or subtraction. The button can only be rotated while it is being pushed down.

Over the years that the Manus was in production, small improvements were made. These variations are unofficially denoted with the letters A to F. This is a type E with serial number 12,208, which dates it to about 1948.

This machine has automatic division. Set up the numerator in the register (as many decimal places to the left as possible). Then shift the carriage as far to the right as possible, and push in the carriage knob. Set the input to the denominator, again at the left end. Set the counter direction switch to subtract, and clear the counter. Then simply repeatedly turn the crank. Whenever the register underflows, the carriage is moved a half-step to the left so that the next turn adds the denominator back. This then overflows the register and moves the carriage another half-step, ready to subtract from the next decimal position. This repeats until the carriage arrives at the far left location, where the register is disconnected and further turns of the crank have no effect.

The latched gear mechanism of the Manus is somewhat reminiscent of the Marchant XA. Instead of pinwheels in which the number of teeth vary, it uses gear wheels that can connect to or disconnect from the central axle. While the crank turns the axle around, the stationary setting lever acts like a cam, and the cam follower on the rotating axle then either locks or unlocks the gear. In effect the gear rotates by an amount that is proportional to the lever setting.

Video

Below is a video I made that demonstrates the Hamann Manus E.

Hamann Manus F

The Hamann Manus F is very similar to the Manus type E above, but it has several small improvements, mainly to the clearing mechanisms. The clearing lever for the counter has been moved to the right hand side of the carriage, next to the clearing lever for the main register. This allows both clearing levers to be operated simultaneously with one hand. Clearing the input is done by lifting a bar that pushes the input pins up to zero. The input pins are much easier to move since the they no longer need to be spring-loaded.

This machine has serial number 15421.

Video

Below is a video I made that demonstrates the Hamann Manus F.

Hamann Delta

The Hamann Delta is an electrically driven calculator with a full keyboard. Its mechanism is otherwise very similar to the Hamann Manus.

At the front right are four buttons: Two buttons for shifting the carriage, as well as buttons for subtraction and addition. The latter buttons will set the carriage into subtraction or addition mode and then activate the electric motor. The motor will keep running while the button is depressed, so this performs repeated addition making multiplication easy. There is a second addition button to the right of the keyboard, and this is purely for adding because the motor stops after one addition, and the keyboard is is automatically clears. On the left there is a switch lever that sets the counter direction, i.e. whether it counts the net additions or net subtractions. The carriage has a knob that allows the carriage to be released and shifted any amount, or pushed in to set division mode.

As with the Hamann Manus, this machine has automatic division. It is is performed in almost exactly the same way. You set the numerator in the register as far to the left as possible, and the divisor in the input. Set the counter direction to subtractions, shift the carriage to the right, and push in the carriage knob to set division mode. Pressing the subtraction button then starts the process.

The machine is supplied with a detachable crank handle. It is normally stored in a holder on the back of the case, but it can easily be inserted in a hole on the right when no electricity is available.

This machine has serial number 1368. The Hamann Delta is a rare model. Very few can be found online, such as #1231, #2307, #????. Probably fewer than 1500 were made, but it is hard to be sure with so little data.

Video

History

Christel Hamann (1870-1946) was a highly prolific and inventive designer of calculating machines. He founded his own company in 1896, at which his first machines were made. The full range of his lesser known early work is somewhat unclear. It is possible that he started with troncet adders and pinwheel machines, as his name has been linked to the Trick (troncet adder) and the Berolina (pinwheel machine) due to some of his patents. His first proper machine design was called the Gauss, and was a cylindrical machine with a single stepped drum at the centre and number wheels arranged around it. He patented this in 1902. This principle had been used by Philipp Matthäus Hahn in the 1770s to make a handful of machines, but the Gauss was simpler, and about a thousand were made. The culmination of the principle was the Curta calculator from 1946 by Curt Herzstark.

In 1905 he developed and patented an entirely new principle, proportional levers. Similar to stepped drum machines the input is done by sliders, one for each digit, and the slider shifts a gear along an axle so that it engages with the mechanism. In this case that is not a stepped drum for each digit, but a set of ten parallel toothed racks shared by all the input digits. These toothed racks are pivoted to an arm, and when one end of that arm swings out, the racks move different amounts, varying from 0 to 9 units. The register wheels move in one direction only, so when the racks have returned to their starting position the input has been added to the register. For subtraction the other end of the arm is moved so that complementary digits are added. Hamann called this machine the Euklid.

In 1907 Hamann's company was bought by Mercedes Bureaumaschinenwerke. They continued to make the Gauss for a few years, and made the Mercedes Plus which was an adding machine that Hamann designed, but it was mainly the Euklid machines that became successful and were developed further. Mercedes-Euklid models, all based on the same principle, were produced until the 1960s.

In 1922 Hamann started working for Deutsche Telephonwerke GmbH, or DTW, which later became Deutsche Telephonwerke und Kabelindustrie AG, or DeTeWe. It seems that he essentially ran a daughter company Hamann Rechenmaschinen. There he developed the Hamann Manus, of which the model A was released in 1925. Before then only Madas had made machines with fully automatic division, but they were much larger machines. This was the first compact calculator with automatic division. There followed models B to F, and finally R. See the description of my Manus E above for more details about the mechanism. Below is a table with information about these Hamann Manus models. Unless otherwise specified, later models in the table also have all the characteristics of the previous models.

There is some disagreement on what constitutes the model D, as some consider only the machines with serial numbers 8200-8230 to be of that model, with the rest being model E.

In his time at DeTeWe Christel Hamann also developed many other machines such as the Delta, Elma, Selecta, and various Automat models. These were electrically driven machines that were based on the same mechanism as the Hamann Manus. He also experimented with relays used by telephone industry, and in 1931 patented one of the earliest electric calculators using that technology. Hamann died in 1946. The company developed the Hamann 300, a calculator model with a 10-key number pad. In 1958 DeTeWe sold off Hamann Rechenmaschinen GmbH to Marchant. This occurred at the time that Marchant fused with Smith-Corona to become SCM, so Hamann Rechenmaschinen GmbH became a wholly owned daughter company of SCM. Further calculator models followed until the end of the 1960s (models 350, 400, 450, 500, 505, 1630).

Books and Manuals

Handhabung der Hamann Manus Rechenmaschine    (PDF, 10.7 MB or archive.org)
Deutsche Telephonwerke und Kabelindustrie A.-G.
1937-1944
48 page stapled booklet
226mm × 156mm

This booklet is the manual for the Hamann Manus in the German language. It has no copyright year, but the pictures are of the model D so it was presumably printed between 1937 and 1944.

Promotional material

36-card deck of playing cards
DeTeWe, and Max Kranz, Augsburg
1930s
Box 62mm × 102mm × 12mm; Card 56mm × 100mm

This is a deck of playing cards promoting Hamann calculators. The box has a picture of some type of Hamann Automat on one side, and a type of Hamann Selecta on the other, which probably dates this to the 1930s. The cards are a 36-card German deck, so it has the values 6 to 10, O, U, K and A of the four suits bells, hearts, leaves and swords. The card design is a Bavarian pattern of a Stralsund type.

Hamann leaflet
DeTeWe, Deutsche Telephonwerke und Kabelindustrie AG
1938?
6-section folded leaflet
Folded 101mm × 148mm, unfolded 600mm × 148mm

A German leaflet for many of the Hamann models. It shows the Manus, Elma, Automat V, Delta, and the Selecta.

Hamann 300 Flyer
DeTeWe, Deutsche Telephonwerke und Kabelindustrie AG
1953-1959
2-sided small flyer
83mm × 126mm

A small German flyer for the Hamann 300, an electrically driven calculator with a 10-key keyboard, automatic division, and back transfer from both the main register and the counter.

Hamann E Flyer
DeTeWe, Deutsche Telephonwerke und Kabelindustrie AG
1953-1959
1-sided small flyer
105mm × 148mm

A small German flyer for the Hamann E, essentially an electrically driven version of the Hamann Manus.

Articles and Advertisements

I have not found many articles and advertisements relating to the Hamann machines in online archives.

Here is the entry in Ernst Martin's 1925 book Die Rechenmaschinen:

Here are a few other articles that mention Hamann.

Lastly, here are some advertisements. The first one is for the Gauss, the last includes a Marchant Hamann.

Patents

Links

• Rechnerlexikon has a page for the Hamann Manus A-F, the Hamann Manus R, and has some material about Christel Hamann.
• Rechenmaschinen-Illustrated has a page about Hamann calculators, and also an English translation of the Hamann Manus manual.
• Computer Timeline has a biography page for Christel Hamann
• Tiny Henst's collection includes a Manus R
• Cris Vande Velde has a Manus C
• Christian Hamann has a Manus C, Manus D, Manus R
• Wolf-G Blümich has a page about the Hamann Manus, as well as a detailed Table of Manus models.
• Rechenwerkzeug.de has a page listing the Hamann DeTeWe machines.

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