Evolving Design - Lecture3. Mechanical calculators_part 2
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    Evolving Design - Lecture3. Mechanical calculators_part 2 Evolving Design - Lecture3. Mechanical calculators_part 2 Presentation Transcript

    • Rise & Fall of the Mechanical Calculator Part 2 Calculating MachinesPaul Breedveld, Dept. Bio-Mechanical Engineering
    • Contents 1. Introduction 2. Calculating Principles 3. Automation, Speed & Miniaturisation 4. Overtaken & Forgotten 5. Summaryintroduction calculating automation overtaken summary
    • Introduction input register (key-matrix) number result register wheelAdding Machines (Comptometer) – working principleintroduction calculating automation overtaken summary
    • Introduction hundreds 002 006 099 tens units 003 + 007 + 001 + 005 013 100 add & carry mechanism number wheelAdding Machines (Comptometer) – working principleintroduction calculating automation overtaken summary
    • Introduction 1. C = A – B 4199 = 9826 – 5627 2. Take from every digit of B the 9-complement B* = 4372 3. Add 1 to last digit of B* B** = 4373 4. Add B** to A A + B** = 14199 5. Subtract 1 from first digit of answer C = 4199 Substracting by adding: the 9-complement methodintroduction calculating automation overtaken summary
    • Introduction Adding Machines • Addition & subtraction easy • Multiplication & division awkward Calculating Machines • Multiplication & division also easy, • (semi) automizedintroduction calculating automation overtaken summary
    • Calculating Principles • Working Principle • Leibniz Wheel Machines • Pinwheel Machines • Ratchet Wheel Machines • Proportional Lever Machines principle Leibniz wheel pinwheel ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Working Principle principle Leibniz wheel pinwheel Arithmometer (1851): first commercial calculator ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Working Principle carriage result register counter register +/− lever input register crank Arithmometer (1851): first commercial calculatorintroduction calculating automation overtaken summary
    • Working Principle 547 312 x ?? 1 “+” turn Multiplication by repeated additionintroduction calculating automation overtaken summary
    • Working Principle 547 312 x 547 1 “+” turn Multiplication by repeated additionintroduction calculating automation overtaken summary
    • Working Principle 547 312 x 1094 2 “+” turns Multiplication by repeated additionintroduction calculating automation overtaken summary
    • Working Principle 547 312 x 1094 2 “+” turns 0+ Multiplication by repeated additionintroduction calculating automation overtaken summary
    • Working Principle 547 312 x 1094 2 “+” turns 0+ 1094 Multiplication by repeated additionintroduction calculating automation overtaken summary
    • Working Principle 547 312 x 1094 2 “+” turns 5470 + 1 “+” turn 6564 Multiplication by repeated additionintroduction calculating automation overtaken summary
    • Working Principle 547 312 x 1094 2 “+” turns 5470 1 “+” turn 00 + 6564 Multiplication by repeated additionintroduction calculating automation overtaken summary
    • Working Principle 547 312 x 1094 2 “+” turns 5470 1 “+” turn 54700 + 1 “+” turn 61264 Multiplication by repeated additionintroduction calculating automation overtaken summary
    • Working Principle 547 312 x 1094 2 “+” turns 5470 1 “+” turn 109400 + 2 “+” turns 115964 Multiplication by repeated additionintroduction calculating automation overtaken summary
    • Working Principle 547 312 x 1094 2 “+” turns 5470 1 “+” turn 164100 + 3 “+” turns 170664 Multiplication by repeated additionintroduction calculating automation overtaken summary
    • Working Principle 547 312 x 1094 2 “+” turns 5470 1 “+” turn 164100 + 3 “+” turns 170664 6 “+” turns Multiplication by repeated additionintroduction calculating automation overtaken summary
    • Working Principle123 / 3936 ??  1 “+” turns Division by repeated subtractionintroduction calculating automation overtaken summary
    • Working Principle123 / 3936 1  1 “+” turns 123 2706 Division by repeated subtractionintroduction calculating automation overtaken summary
    • Working Principle123 / 3936 2  2 “+” turns 246 1476 Division by repeated subtractionintroduction calculating automation overtaken summary
    • Working Principle123 / 3936 3  3 “+” turns 369 246 Division by repeated subtractionintroduction calculating automation overtaken summary
    • Working Principle123 / 3936 4  4 “+” turns 369999990166 <0 ERROR Division by repeated subtractionintroduction calculating automation overtaken summary
    • Working Principle123 / 3936 3  4 “+” turns 369 1 “+” turns (correction) 246 Division by repeated subtractionintroduction calculating automation overtaken summary
    • Working Principle 123 / 3936 31 4 “+” turns 369 1 “+” turns (correction) 246  1 “+” turns 123 123 Division by repeated subtractionintroduction calculating automation overtaken summary
    • Working Principle 123 / 3936 32 4 “+” turns 369 1 “+” turns (correction) 246  2 “+” turns 246 0 Division by repeated subtractionintroduction calculating automation overtaken summary
    • Working Principle 123 / 3936 32 4 “+” turns 369 1 “+” turns (correction) 246  2 “+” turns 246 7 turns 0 Division by repeated subtractionintroduction calculating automation overtaken summary
    • Working Principle principle Leibniz wheel pinwheel ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Working Principle principle Leibniz wheel pinwheel ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines principle Leibniz wheel pinwheel Leibniz wheel ratchet wheel (stepped drum, Staffelwalz) proportional leverintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines carriage crank Leibniz calculator (1673-1694)introduction calculating automation overtaken summary
    • Leibniz Wheel Machines result register input register Leibniz calculator: registersintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines 0-9 +/− Arithmometer: Leibniz wheel mechanismintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines Arithmometer: Leibniz wheel mechanismintroduction calculating automation overtaken summary
    • Leibniz Wheel Machinesintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines Keys instead of slidesintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines Input methods: slides, key-matrixintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines Drawback Leibniz wheel: width Very large machines (40-50 cm wide) Registers difficult to readintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines RheinmetallSolution 1: ImprovedLeibniz wheel configurations MADASintroduction calculating automation overtaken summary
    • Leibniz Wheel MachinesSolution 1: ImprovedLeibniz wheel configurations MADASintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines RheinmetallSolution 1: ImprovedLeibniz wheel configurationsintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines +5 +4 +3 Solution 2: Split Leibniz wheel (Monroe, Brunsviga)introduction calculating automation overtaken summary
    • Leibniz Wheel Machines +5 +5 +4 +3 +2 +1 +0 Solution 2: Split Leibniz wheel (Monroe, Brunsviga)introduction calculating automation overtaken summary
    • Leibniz Wheel Machines +5 +9 +8 +7 +6 +5 Solution 2: Split Leibniz wheel (Monroe, Brunsviga)introduction calculating automation overtaken summary
    • Leibniz Wheel Machines Solution 2: Split Leibniz wheel (Monroe, Brunsviga)introduction calculating automation overtaken summary
    • Leibniz Wheel Machines Solution 2: Split Leibniz wheel (Monroe, Brunsviga)introduction calculating automation overtaken summary
    • Leibniz Wheel Machines Monroe Calculator (first model, 1908)introduction calculating automation overtaken summary
    • Leibniz Wheel Machines Monroe Calculator (later model) from belowintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines End 19th century: • Drawback Leibniz machines: very large • Split Leibniz wheel not yet invented Solution: Pinwheel mechanism principle Leibniz wheel pinwheel ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Leibniz Wheel Machines End 19th century: • Drawback Leibniz machines: very large • Split Leibniz wheel not yet invented Solution: Pinwheel mechanism principle Leibniz wheel pinwheel ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Pinwheel Machines principle Inventors: Leibniz wheel pinwheel • Baldwin, 1876, USA ratchet wheel • Ohdner, 1878, Russia proportional leverintroduction calculating automation overtaken summary
    • Pinwheel Machines Pinwheel (Sprossenrad)introduction calculating automation overtaken summary
    • Pinwheel Machines Pinwheel (Sprossenrad)introduction calculating automation overtaken summary
    • Pinwheel Machines crank carriageintroduction calculating automation overtaken summary
    • Pinwheel Machines Carry mechanismintroduction calculating automation overtaken summary
    • Pinwheel Machines Carry mechanismintroduction calculating automation overtaken summary
    • Pinwheel Machines counter input result – +introduction calculating automation overtaken summary
    • Pinwheel Machines Pinwheel Machines: a great commercial successintroduction calculating automation overtaken summary
    • Pinwheel MachinesMarchant calculators: simplified pinwheel mechanism input via slides or key-matrixintroduction calculating automation overtaken summary
    • Pinwheel Machines Brunsviga DoppelDouble pinwheel calculators for military applicationsintroduction calculating automation overtaken summary
    • Pinwheel Machines Marchant Twinplex (simplified pinwheel) US variant of German Brunsviga Doppel that was not available in US during WW2Double pinwheel calculators for military applicationsintroduction calculating automation overtaken summary
    • Pinwheel Machines 10-key Facit pinwheel calculatorsintroduction calculating automation overtaken summary
    • Pinwheel Machines 10-key Facit pinwheel calculatorsintroduction calculating automation overtaken summary
    • Pinwheel Machines Detailed information about pinwheel calculators: http://www.boelters.de/Rechenmaschinen/index.html Detailed information about Facit calculators: http://www.rechenautomat.de/Facit/index.html Facit assembly hall (1954)introduction calculating automation overtaken summary
    • Pinwheel Machines Drawback Pinwheel: high inertia Less suitable for high-speed applications Solution: Ratchet wheel mechanism principle Leibniz wheel pinwheel ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Pinwheel Machines Drawback Pinwheel: high inertia Less suitable for high-speed applications Solution: Ratchet wheel mechanism principle Leibniz wheel pinwheel ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Ratchet Wheel Machines ratchet wheel fixed disc setting lever swivel principle Leibniz wheel pinwheel Ratchet wheel (Schaltklinken) ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Ratchet Wheel Machines Hamann Manus (DeTeWe, 1932)introduction calculating automation overtaken summary
    • Ratchet Wheel Machines End 19th century: • Drawback Leibniz machines: very large • Pinwheel still patented (Brunsviga) • Ratchet wheel not yet invented Solution: Proportional lever mechanism principle Leibniz wheel pinwheel ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Ratchet Wheel Machines End 19th century: • Drawback Leibniz machines: very large • Pinwheel still patented (Brunsviga) • Ratchet wheel not yet invented Solution: Proportional lever mechanism principle Leibniz wheel pinwheel ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Proportional Lever Machines tooth rack rotation over 8 teeth rotation over 7 teeth rotation over 4 teeth rotation over 3 teeth principle Leibniz wheel pinwheelpivot ratchet wheel proportional leverintroduction calculating automation overtaken summary
    • Proportional Lever Machinesintroduction calculating automation overtaken summary
    • Proportional Lever Machines switching wheelintroduction calculating automation overtaken summary
    • Proportional Lever Machines switching wheel Function switching wheel: • Clockwise gearwheel rotation passes to number wheel • Anti-clockwise rotation has no effect on number wheelintroduction calculating automation overtaken summary
    • Proportional Lever Machines driving wheel: continuous motion switching wheel: stepwise motionintroduction calculating automation overtaken summary
    • Proportional Lever Machines 1: turn 2: turn 3: stop 4: stopintroduction calculating automation overtaken summary
    • Proportional Lever Machinesintroduction calculating automation overtaken summary
    • Proportional Lever Machines pivot not at top.. but in middle!Floating tooth racks for substraction via 9-complements introduction calculating automation overtaken summary
    • Proportional Lever Machines addition: +0 +1 +2 upper tooth +3 +4 +5 rack locked +6 +7 +8 +9 +9 ≈ −0 +8 ≈ −1 +7 ≈ −2 substraction: +6 ≈ −3 +5 ≈ −4 +4 ≈ −5 lower tooth +3 ≈ −6 +2 ≈ −7 rack locked +1 ≈ −8 +0 ≈ −9Floating tooth racks for substraction via 9-complements introduction calculating automation overtaken summary
    • Proportional Lever Machines Mercedes Euklid No. 1 (1905)introduction calculating automation overtaken summary
    • Proportional Lever MachinesMercedes Euklid No. 1 insideintroduction calculating automation overtaken summary
    • Proportional Lever Machines Mercedes Euklid No. 29 (1931)introduction calculating automation overtaken summary
    • Proportional Lever Machines Mercedes Euklid No. 29 insideintroduction calculating automation overtaken summary
    • Proportional Lever Machinesintroduction calculating automation overtaken summary
    • Automation, Speed & Miniaturisationintroduction calculating automation overtaken summary
    • Automation Electric Monroe calculator, split Leibniz wheelintroduction calculating automation overtaken summary
    • Automatic Division Needed for auto division: • Auto <0 ERROR detection (999999..) • Auto switching between “− ” and “+” • Auto carriage shift123 / 3936 32 4 “−” turns 369 1 “+” turn (correction) 246 2 “−” turns 246 7 turns 0introduction calculating automation overtaken summary
    • Automatic Division Manual auto division calculators (Mercedes Euklid No. 29 & Hamann Manus)introduction calculating automation overtaken summary
    • Automatic Division Electric auto division calculatorHamann 300 (1953), ratchet wheel, 10-key (pin-box)introduction calculating automation overtaken summary
    • Automatic Division & Multiplication Needed for auto multiplication: • Multiplier memory • Counting mechanism 547 • Auto carriage shift 312 x 1094 2 “+” turns 5470 1 “+” turn 164100 + 3 “+” turns 170664 6 “+” turnsintroduction calculating automation overtaken summary
    • Automatic Division & Multiplication Cellatron R44SM MADAS 20BTG (1964, DDR/USSR) (1936, Switzerland)proportional lever, key-matrix Leibniz wheel, key-matrix Fully automatic 4-function (+,−,x,/) calculatorsintroduction calculating automation overtaken summary
    • Automatic Division & Multiplication Cellatron R44SM inside
    • Automatic Division & Multiplication
    • Automatic Division & Multiplication MADAS 20BTG from below ~450 adds/min ~4000 parts ~20 Kg
    • Automatic Division & Multiplication MADAS 20BTG keyboard removed
    • Automatic Division & Multiplication MADAS 20BTG (1936) from below Detailed description of MADAS calculator:http://home.vicnet.net.au/~wolff/calculators/Tech/MadasATG/Intro.htm Overview of advanced 4-function calculators http://www.mortati.com/glusker/elecmech/index.htm
    • Speed - Proportional Gear Machines “Conventional” calculating machines: • Mechanisms are continuous by nature • Calculating is discrete by nature Rapid start-stop motions required during division & multiplication Low speed & much noiseintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines “Conventional” calculating machines: • Mechanisms are continuous by nature • Calculating is discrete by nature Rapid start-stop motions required during division & multiplication Low speed & much noise Proportional gear machines: • Calculating with continuous motion High speed & less noiseintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines Marchant Silent Speed calculator Fastest calculator from 1932 till ~1970 (~1200 adds/min ≈10 flops)introduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines A. Press number key B. Press “+” key 1. Select Select gear proportional to selected number 2. Actuate Drive number wheels with selected gear speed 3. Carry Perform continuous carry transfer 4. Digitize Switch from continuous to discrete output C. Read output automatic machine operation Sequence of steps in a proportional gear machine (during adding)introduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines A. Press number key B. Press “+” key 1. Select Select gear proportional to selected number 2. Actuate Drive number wheels with selected gear speed 3. Carry Perform continuous carry transfer 4. Digitize Switch from continuous to discrete output C. Read output Example: +2: number wheel rotates 2 times as fast as with +1 +5: number wheel rotates 5 times as fast as with +1 +7: number wheel rotates 7 times as fast as with +1 etc.introduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines Example: +2: number wheel rotates 2 times as fast as with +1 +5: number wheel rotates 5 times as fast as with +1 +7: number wheel rotates 7 times as fast as with +1 etc.introduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines gear-arm Manual gear Motorized gear Step 1: Select selection setting & lockintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines• Each key-row has 5 gear-arms• 1 arm switches to gear position• Other arms switch to free positionintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines• Each key-row has 5 gear-arms• 1 arm switches to gear position• Other arms switch to free positionintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machinesintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machinesintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines Gearbox with 100 gears!introduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines Step 2: Actuate Step 3: Carryintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines Speed proportional to selected number Step 2: Actuate Step 3: Carryintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machinesintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines Adding with planetary gears for continuous carry transferintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines Gear ratio for carry transfer number wheelintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines Number of teeth → gear ratio 16/40 10/40 40 16 40 10introduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines 16/40x10/40 = 160/1600 = 1/10 16/40 10/40 40 16 40 10introduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines “95” displayed continuous “95” displayed discreteDouble planetary gear system• One for carry transfer• One for digitizing Step 4: Digitizeintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machinesintroduction calculating automation overtaken summary
    • Speed - Proportional Gear MachinesExtremely complexyet very reliable~6000 partsintroduction calculating automation overtaken summary
    • Speed - Proportional Gear MachinesExtremely complexyet very reliable~6000 parts Detailed description of Marchant Silent Speed Calculator: http://home.vicnet.net.au/~wolff/calculators/Tech/MarchantDRX/Intro.htmintroduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines Original design of Joseph Sinel (very famous Industrial Designer)introduction calculating automation overtaken summary
    • Speed - Proportional Gear Machines CBS Tel- & Rekenbureau (1958)introduction calculating automation overtaken summary
    • Miniaturisation - the Curta • Invented by Curt Werzstark • Designed during WWII in • concentration camp Buchenwald • Produced by company Contina AG • in Liechtenstein • First & only pocket calculator till 1970 • Marvel of fine-mechanical engineering • “Cult-object” under collectorsintroduction calculating automation overtaken summary
    • Miniaturisation - the Curta Miniaturisation of Leibniz wheel mechanismintroduction calculating automation overtaken summary
    • Miniaturisation - the Curta Ring of gearwheels around one Leibniz wheelintroduction calculating automation overtaken summary
    • Miniaturisation - the Curta clearing counter register crank lever result register input registerintroduction calculating automation overtaken summary
    • Miniaturisation - the Curta Models: Curta 2 (15 digits) & Curta 1 (11 digits)introduction calculating automation overtaken summary
    • “Complimented” Leibniz wheel
    • Miniaturisation - the Curta “snap-in” dent helical groove (translation setting knob to rotation number wheel)introduction calculating automation overtaken summary
    • Miniaturisation - the Curta Curta gearwheels: • Asymmetric teeth shape • Advantage (most likely): • Larger teeth, more robust • Consequence: • Rotation Leibniz wheel in only 1 direction Substraction by 9-complement method Complex shape Leibniz wheelintroduction calculating automation overtaken summary
    • Miniaturisation - the Curta 9 8 7 6 5 +5 4 +4 3 2 1 0 Conventional Leibniz wheelintroduction calculating automation overtaken summary
    • Miniaturisation - the Curta 9 8 7 6 5 4 +4 3 +3 2 1 0 Conventional Leibniz wheelintroduction calculating automation overtaken summary
    • Miniaturisation - the Curta 0 9 1 8 2 7 3 6 4 5 5 4 6 3 +3 7 2 8 1 9 0 Second Leibniz wheel with 9-complementsintroduction calculating automation overtaken summary
    • Miniaturisation - the Curta 0 9 1 8 2 7 3 6 4 5 5 4 6 3 +3 7 2 8 1 9 0 Segmented Leibniz wheelsintroduction calculating automation overtaken summary
    • Miniaturisation - the Curta 0 9 1 8 2 7 3 6 4 5 5 4 6 3 +3 7 2 8 1 9 0 Segmented Leibniz wheelsintroduction calculating automation overtaken summary
    • Miniaturisation - the Curta 0 9 1 8 2 7 3 6 4 5 5 4 6 3 7 +3 −3 2 8 1 9 0Complimented Leibniz wheel (addition & substraction)introduction calculating automation overtaken summary
    • Miniaturisation - the Curta 0 9 1 8 2 7 3 6 4 5 5 4 6 3 7 2 8 1 9 0Complimented Leibniz wheel (addition & substraction)introduction calculating automation overtaken summary
    • Miniaturisation - the Curta – 9 0 + 1 8 2 7 3 6 4 5 5 4 6 3 7 2 8 1 9 0Complimented Leibniz wheel (addition & substraction)introduction calculating automation overtaken summary
    • Miniaturisation - the Curta More information about the Curta: http://www.curta.de/kr11/index.htm http://www.vcalc.net/introduction calculating automation overtaken summary
    • Miniaturisation - the Curtaintroduction calculating automation overtaken summary
    • Overtaken & Forgottenintroduction calculating automation overtaken summary
    • Overtaken & Forgotten Enigma: • German WW2 electro-mechanical • coding & decoding machine • Used to code & decode • messages to/from German • U-boots & troopsintroduction calculating automation overtaken summary
    • Overtaken & Forgotten Bletchley Park, UKSecret Allied decoding center Birth of the computerintroduction calculating automation overtaken summary
    • Overtaken & Forgotten 1946: ENIAC First electronic computer >100,000 transistors 19,000 vacuum tubes 1,500 relais 200 kW
    • Overtaken & Forgotten Very expensive very heavy (33kg) less reliable but.. SILENT! 1962: Anita - first electronic desk calculatorintroduction calculating automation overtaken summary
    • Overtaken & Forgotten1968: Friden RSRMost advancedmechanical calculator+,−,x,/,√,x2~25 Kg, $11951972: HP-35First scientificpocket calculator+,−,x,/,√,sin,cos,tan,arcsin,arccos,arctan,ln,log,e,xy,1/x255 g, $395introduction calculating automation overtaken summary
    • Overtaken & ForgottenMarchant, 1973“When I arrived at the Hotel Thursdaynight, all the managers from the WestCoast were there. We were sure whatwe all expected was about to cometrue, and it did; At a meeting on Fridaywe were all dismissed with 2 weekspay, and so ended 23 years ofservice.”(source:http://www.webcom.com/calc/articles/marchant/marchant.htm)1968-1973:End of a mechanical era…introduction calculating automation overtaken summary
    • Overtaken & ForgottenFacit, 1971“In 1970, the company had reached thepeak of its growth, with more than14,000 employees worldwide. In 1971,modern Japanese-made calculatorswere introduced to the market, instantlymaking the mechanical calculatorsmanufactured by Facit obsolete. As aresult, Facit went out of businessvirtually over-night.”(source: http://en.wikipedia.org/wiki/Facit)1968-1973:End of a mechanical era…introduction calculating automation overtaken summary
    • Overtaken & ForgottenLast Hamann calculator, DeTeWe, 1970“Das Desaster war aber nicht abzuwenden: Als das Werk in Berlin 1970geschlossen wurde, gingen von den ca. 5000 hergestellten Maschinenetwa 2500 direkt vom Verkaufslager auf den Schrottplatz. DieRechenmaschinen mit dem Namen "Hamann" verschwanden damit ausden Verkaufsregalen des Büromaschinenhandels.Der Konstrukteur der Maschine konnte den sich abzeichnenden Mißerfolgnicht überwinden und nahm sich 1968 das Leben.”(source:http://www.ph-ludwigsburg.de/fileadmin/subsites/2e-imix-t-01/user_files/mmm/mmm_online/)1968-1973:End of a mechanical era…introduction calculating automation overtaken summary
    • Summaryintroduction calculating automation overtaken summary
    • Summary Detailed overview of nearly all mechanical adding & calculating machines: http://home.vicnet.net.au/~wolff/calculators/welcome.htmintroduction calculating automation overtaken summary