John Wolff's Web Museum

The Bell Punch Company - PLUS, Sumlock, and Anita


 

Contents

Sumlomatic
Sumlock "Sumlomatic", c.1960

Overview

The Bell Punch Company (BPC) was established in London in 1878, and took its name from its original product - a tram conductor's registering ticket punch. The company expanded into ticket printing and issuing equipment for trams, buses, and cinemas, racecourse betting tickets, and taxi meters. Their activities were generally related to "cash control systems", and were coordinated through a holding company "Control Systems Ltd" from 1927. Both companies established branches in Australia and other Commonwealth countries.

In 1936 the Bell Punch Company purchased the rights to a small half-keyboard adding machine which was sold as the "PLUS Adder". Larger full-keyboard versions with Comptometer-style safety mechanisms were developed and marketed under the name "Sumlock". The London Computator Corporation was established in 1940 to handle the calculator business, but the nameplate soon reverted to The Bell Punch Company.

The PLUS and Sumlock machines were very popular in Britain and Commonwealth countries. They continued in production for almost 40 years, until replaced by computers and electronic calculators in the 1970s.

In the late 1950s the Bell Punch Company acquired the British rights to the Comptometer name from the ailing Comptometer Corporation (formerly Felt & Tarrant) of Chicago. When Comptometer production ended in 1961, the Bell Punch Company exported re-badged Sumlock machines to America to be sold as new-model Comptometers.

In the mid-50s the company started to introduce electronics into its product lines, and began work on an electronic calculator. The world's first commercial electronic calculator, the Sumlock "Anita", was introduced in 1961. The Sumlock Anita Electronics Company was established in 1966 to handle the calculator business (including the mechanical calculators), but was taken over by the American Rockwell organisation in 1973. Rockwell soon lost interest in calculators in favour of their aerospace business, and Sumlock Anita was effectively disbanded in 1976. The Bell Punch Company continued on with its traditional ticketing products, until it too was finally broken up and sold in 1986.


The "PLUS" Half-Keyboard Adder

The original mechanism of the PLUS Adder was designed by Guy Petter (of the Petter oil engine family) during the 1920s. The design was acquired by the Bell Punch Company in 1936, and was put into immediate production. A greatly improved mechanism was developed by Christopher Webb of Bell Punch in 1938, and formed the basis of all subsequent models.

The PLUS adder is a "half-keyboard" machine with keys from 1 to 5 only. It was common practice among skilled Comptometer operators to use only the lower half of the keyboard for addition, as it was found to be less tiring to enter (eg) 8 by striking 4 twice, than to move one's whole arm to make a deeper and firmer stroke on the 8 key. The half-keyboard machines were much smaller, lighter, and cheaper than the full-keyboard models, and were entirely satisfactory provided one had no need for anything beyond simple addition.

The mechanism of Webb's improved machine was quite different to both the Comptometer and the Burroughs Calculator, but it provided several of the Comptometer-style safety features. The machine would not register an amount if a key was not fully depressed (although there was no error indication), and it would not allow a keystroke to be repeated until the key had fully risen. A definite start-from-clear signal was provided by a latching mechanism on the clearing lever.

The development of the PLUS Adder from the 1930s to the 1960s is described further below. Click on the photos for larger illustrations.


Plus Model SJ Bell Punch "PLUS Adder", Model SJ, S/N 336
5/6 columns, Sterling currency (no farthings)
Dimensions: 6-1/4"W x 6"D x 4"H
Weight: 3 pounds
Manufactured: Bell Punch Company, London, 1936-

The first version of the PLUS Adder was housed in a black bakelite case. The PLUS name and the manufacturer appear only in a small circular badge or roundel set into the back of the cover. The mechanism operates on the downwards keystroke, with the register advancing in proportion to the depth of travel. A "duplexing" mechanism allows keys in adjacent columns to be operated simultaneously, but there is no protection against incomplete keystrokes. The clearing lever on the right-hand side is pushed downwards to advance the register dials to zero.

This early machine (s/n 336) has only 5 keyboard columns, arranged for Sterling currency without farthings. The display window has 6 digits and a maximum capacity of £999/19/11.


Plus Model A Bell Punch "PLUS Adder", Model A, S/N 3,332
9/9 columns, Sterling currency (no farthings)
Dimensions: 8-1/2"W x 6"D x 4"H
Weight: 5 pounds
Manufactured: Bell Punch Company, London, 1936-

This larger PLUS Model A has 9 columns in both the keyboard and the display register, but is otherwise identical to the machine above.

The nameplate on the base of the machine lists three of the US patents that were filed by Guy Petter from 1923 to 1931. The highest number (1983945) was issued in December 1934.


Plus early Sterling, with farthings Bell Punch "PLUS Adder", Model 509/S, S/N LC/509/SF/2873
9/10 columns, Sterling currency (with farthings)
Dimensions: 9-1/4"W x 7-1/2"D x 5"H
Weight: 9 pounds
Manufactured: London Computator Corporation, England, about 1940.

The first PLUS adder with the improved Webb mechanism was marketed by the London Computator Corporation from about 1940. The mechanism sits on a heavy steel baseplate with substantial rubber feet, and has a die-cast cover with moulded lifting handles. This very early example carries a faded "Bell Punch" transfer on the front, and the remains of the glue which once held the PLUS name in individual metal letters. A larger circular badge is set into the back of the case.

The new mechanism incorporates many of the safety features developed by the Comptometer, although achieved by completely different means. The register advances on the upwards or return stroke of the key, with protection against incomplete keystrokes in both directions. The small clearing lever on the right-hand side has a very short forward movement which returns the numeral wheels backwards to zero. The lever remains latched in the forward position until the first keystroke of the next calculation to provide a Comptometer-style "start from clear" indication.

The new PLUS machines were made in versions with 6, 9, and 12 keyboard columns, although the 9-column version was by far the most popular. The display register always had one extra "overflow" digit at the left-hand side. The machines could be supplied for Sterling currency (with or without farthings), decimal currency, feet and inches, hours, minutes, and seconds, and even tons, hundredweight, and quarters.

The model numbers show the number of keyboard rows and columns (5-09, 5-12, etc), the denominations (S for Sterling, F for farthings, C for decimal, etc), and a (more-or-less) sequential serial number.


Plus 512 Sterling Bell Punch "PLUS Adder", Model 512/F, S/N 512/F/90,075
12/13 columns, Sterling currency (with farthings)
Dimensions: 11-1/2"W x 7-1/2"D x 5"H
Weight: 11 pounds
Manufactured: London Computator Limited, England, late 1940s.

A 12-column PLUS adder for Sterling currency, with farthings, in a plain dark-green case. The lifting handles havebeen deleted, the Bell Punch transfer is rather faded, and the glued-on PLUS letters have all fallen off. The mechanism is still in working order.


Plus early Sterling Bell Punch "PLUS Adder", Model 509/S, S/N 509/S/55751
9/10 columns, Sterling currency (no farthings)
Dimensions: 9-1/4"W x 7-1/2"D x 5"H
Weight: 9 pounds
Manufactured: Bell Punch Company, London, 1940s.

This later 9-column PLUS has replaced the farthings column on the right with an additional pounds column on the left. Farthings were never issued as Australian currency, but half-pence (ha'pennies or 2 farthings) were in genral but declining use until the 1950s. This machine is finished in a plain dark green, and still has its transfers and metal "PLUS" letters.


Plus later Sterling Bell Punch "PLUS Adder", Model 509/S, S/N 509/S/82372Q
9/10 columns, Sterling currency (no farthings)
Dimensions: 9-1/4"W x 7-1/2"D x 5"H
Weight: 9 pounds
Manufactured: Bell Punch Company, London, late 1940s.

The second version of the PLUS adder was finished in a light hammertone green. The clearing handle was made larger and more obvious, and the individual PLUS letters were replaced with a one-piece metal nameplate attached with polished square-headed bolts.


Plus 506 Sterling Bell Punch "PLUS Adder", Model 506/S, S/N 506/S/43,769Q
6/7 columns, Sterling currency (no farthings)
Dimensions: 7"W x 7-1/2"D x 5"H
Weight: 6-1/2 pounds
Manufactured: Bell Punch Company, London, 1950s.

A compact 6-column version of the PLUS adder for Sterling currency.


Plus Sterling converted Bell Punch "PLUS Adder", Model 509/S, S/N 509/S/96597L
9/10 columns, converted to decimal currency
Dimensions: 9-1/4"W x 7-1/2"D x 5"H
Weight: 9 pounds
Manufactured: Bell Punch Company, London, early 1950s.

The next change was to replace the large octagonal keytops with small round buttons in the same colours. The decimal indicators along the result window were no longer individuallly numbered.

This mid-50s machine was originally built for Sterling currency (without farthings), but was rebuilt as all-decimal at the time of Australia's currency conversion in 1966.


Plus late green Bell Punch "PLUS Adder", Model 509/S, S/N 509/S/853,654
9/10 columns, converted to decimal currency
Dimensions: 9-1/2"W x 7-1/2"D x 5"H
Weight: 7 pounds
Manufactured: Bell Punch Company, England, late 1950s.

This late-50s version of the PLUS adder has a re-styled case incorporating a light-weight die-cast baseplate with inbuilt lifting grips. The keytops are now cylindrical and extend through individual holes in the one-piece top cover. The decimal indicators have been deleted entirely. The PLUS badge has been moved to the rear panel, replacing the original embossed circular badge, and the clearing handle has been relocated to the top front corner of the machine. The pressed-metal gears in the register and carry mechanism have been replaced with moulded plastic, but the mechanism is otherwise identical to the earlier models. This machine was originally built for Sterling currency, but was converted to decimal in 1966.

Although this machine was updated successfully, the conversion presented a number of problems for the earlier PLUS machines. Most of the mechanism parts were still available from the factory, although the gears were now being made in plastic rather than metal. However the octagonal and round keytops were no longer available, and there were often difficulties in matching keytop colours. Converted machines will generally be found to contain a mixture of parts from different sources, sometimes including parts stripped from "trade-in" or recycled machines. The resulting colour groupings in the keyboard and registers did not always match the factory originals.


Plus 506 Sterling Bell Punch "PLUS Adder", Model 506/S, S/N 506/S/824197
6/7 columns, converted
Dimensions: 7"W x 7"D x 5"H
Weight: 5-1/4 pounds
Manufactured: Bell Punch Company, London, late 1950s.

A 6-column version of the 1950s PLUS adder, originally built for Sterling currency but converted to decimal.


Plus 509 late decimal Bell Punch "PLUS Adder", S/N 509/C/859,127
9/10 columns, decimal currency
Dimensions: 9-1/2"W x 7-1/2"D x 5"H
Weight: 7 pounds
Manufactured: Bell Punch Company, England, 1960s.

The final version of the PLUS adder was finished in a colour that varies from beige to pink, depending on the light and the time of day. The keytops changed to various shades of grey and white.

This late-model machine was factory-built for decimal currency.


Plus 509 for Imperial weights Bell Punch "PLUS Adder", S/N 509/Z/857,418
9/10 columns, Imperial weights
Dimensions: 9-1/2"W x 7-1/2"D x 5"H
Weight: 7 pounds
Manufactured: Bell Punch Company, England, 1960s.

This Plus adder was factory-built to calculate in Imperial weights, from 1 ounce to 10,000 tons. The Imperial system involves 6 units and six different number bases. One ton of 2240 pounds is divided into 20 hundredweight (abbrev. cwt) of 112 pounds each. The hundredweight is divided into four quarters (qrs) of 28 pounds, and the quarters were divided into two stones of 14 pounds. The pounds (lbs) are divided into 16 ounces (oz). Hundredweight were generally used for heavy bagged goods (cement, stock feed, etc - 20 bags to the ton), stones were only used to express the weights of people, while pounds and ounces were in general and domestic use.

From the right, the columns on this machine are:



The "Sumlock" adding calculator.

During the 1940s Christopher Webb of The Bell Punch Company developed a line of full-keyboard key-driven machines based on an extended version of his improved "Plus" mechanism. The name "Sumlock" was applied to these later machines which included a Comptometer-style locking mechanism to guard against incomplete keystrokes. If a key is not fully depressed, the entry will not register, the key will not rise, and the rest of the keyboard will immediately lock. The operator can complete the keystroke on the conspicuous half-risen key, clear the lock by pressing the release lever, and continue with normal operation.

The Sumlock machine also has protection against incomplete upstrokes, and includes a start-from-clear signal and cutoff levers for use in subtraction. The machine is functionally equivalent to the Felt & Tarrant Comptometer, although based on an entirely different mechanism.

Webb continued to develop the Sumlock machine during the 1950s, adding an electric motor drive, a second "grand-total" register, and finally a semi-automatic multiplier mechanism.

In the late 1950s the ailing Comptometer Corporation of Chicago sold the British rights to the Comptometer name to the Bell Punch Company, and imported Sumlock machines to America to be sold as new-model Comptometers. The machines were branded "Sumlock Comptometer" in Britain, "Sumlock" in the BPC export markets, and in "Comptometer" in America. The machines reached Australia through both the Bell Punch and the Felt & Tarrant distributors, resulting in two competing lines that were identical in all respects, apart from the name badge and the colour scheme. The illustrations below show machines from both sources.


Sumlock 912 Sterling Sumlock Model 912, S/N 912/F/18677
12/13 columns, single register, manual, Sterling (with farthings)
Dimensions: 12-1/2"W x 13"D x 6"H
Weight: 17 pounds
Manufactured: Bell Punch Company, England, c.1945.

This early version of the Sumlock adding calculator was released around the end of the war in the mid-1940s. It is housed in a streamlined cast-alloy casing finished in a light hammetone green, with a distinctive row of black subtraction buttons above the register. This early example was built for Sterling currency with farthings, but has no 10 and 11 keys in the pence column. The 10 and 11 keys were never used for addition, but their absence did introduce some minor complications in other calculations.

The mechanism is the same in principle as the PLUS and uses many of the same components. It has been extended from 5 to 9 rows and provided with Comptometer-style error detection and keyboard locking. The lock release is via the small red button at the right-hand rear.


Sumlock 912 Sterling Sumlock Model 912, S/N 912/S/4A/130611
12/13 columns, single register, manual, decimal currency (converted)
Dimensions: 13"W x 12-1/2"D x 6"H
Weight: 17 pounds
Manufactured: Bell Punch Company, England, 1950s.

The PLUS and Sumlock machines were re-styled in the early 1950s. The cases became more angular, the keytops became cylindrical, the Sumlock received a new one-piece keyplate, and coloured tabs replaced the black subtraction buttons. The clearing lever was relocated to the front right corner, and (on the Sumlock) now performs two separate functions. It is drawn forward to clear the register, or pushed rearward to clear the keyboard lock. The nameplate acquired a new version number "4A", also found on other manually-operated machines as 4A or IVA.

This machine was originally built for Sterling currency (without farthings), but was converted to decimal in 1966.
Sumlock 130611 nameplate


Comptometer Model 12B Bell Punch Comptometer, Model 12B, S/N 951085 F
12/13 columns, single register, manual, converted
Dimensions: 13"W x 12-1/2"D x 6"H
Weight: 17 pounds
Manufactured: Bell Punch Company, England, late 1950s

A late-1950s "Comptometer", made in England by the Bell Punch Company (BPC) for export to the Comptometer Corporation in America. The machine is identical to the "Sumlock" model above, except for the tan colour scheme and the bolt-on name badges. This machine was originally built for Sterling currency (with farthings, but no 10 or 11 keys), but has been converted to decimal.

The large nameplate found on the base of Sumlock machine above was greatly abbreviated for the US Comptometer range. The maker's name and the British patent details have been completely removed (perhaps to conceal its origins), leaving only a model number and a few US and foreign patents. However the steel baseplate of the machine is still clearly stamped "Guaranteed Made in Great Britain". The last US patent listed (2773647) was issued in 1956.
BPC Comptometer nameplate


Comptometer Model 12E Bell Punch Comptometer, Model 12E, S/N 904373F
12/13 columns, single register, electric, converted
Dimensions: 13"W x 13-1/2"D x 6-1/2"H
Weight: 23 pounds
Manufactured: Bell Punch Company, England, late 1950s

This is a motorised version of the 12-column machine above. The case has been extended rearwards and raised by half an inch to accommodate the motor and electricals. The motor drive provides a lighter touch, but is rather noisy in operation. The clearing key has returned to its original single function, as the powered actuator eliminates any problems with incomplete keystrokes.

The driving mechanism of the electric machines is described in Webb's US Patent 2756932, filed in 1951 and issued in 1953. All of the Sumlock electric machines had a version number starting with 5 or V.


Sumlock 912 dual register Sumlock "Duolectric", Model 912, S/N 912/S/Va/510,003B
12/13 columns, dual register, electric, Sterling currency
Dimensions: 13"W x 13"D x 8"H
Weight: 29 pounds
Manufactured: Bell Punch Company, England, 1950s.

The Sumlock "Duolectric" has an electric motor drive and a second "grand total" register in the raised section at the rear. This 12-column machine is aranged for Sterling currency, without farthings.

Pulling forward on the control at the centre right of the keyboard will add the contents of the front register to the grand-total register, and leave the front register clear for the next calculation. Pressing rearwards on the control will subtract from the grand total. The clearing control at the front right moves forward and rearward to clear the corresponding registers.

The dual register mechanism is described in Webb's US Patent 2773647, filed in 1951 and issued in 1953.


Comptometer Model 12D Bell Punch Comptometer, Model 12D, S/N 904445 S
12/13 columns, dual register, electric, Sterling currency
Dimensions: 13"W x 13"D x 8"H
Weight: 29 pounds
Manufactured: Bell Punch Company, England, late 1950s

This is the "Comptometer" version of the 12-column "Duolectric" machine above.


Sumlock 909 dual register Sumlock "Duolectric", Model 909, S/N 909/S/Va/504,163
9/10 columns, dual register, electric, converted
Dimensions: 10-1/2"W x 13"D x 8"H
Weight: 25 pounds
Manufactured: Bell Punch Company, England, 1953-

This photo shows a smaller 9-column version of the dual-register electric machine, originally built for Sterling currency. The conversion to decimal was apparently done by Control Systems' Australian branch, whose label appears on the front of the machine.


Sumlock FigureFlow Sumlock "Figure-flow", S/N 909/IVB/C/143,875
9/10 columns, single register, manual, decimal
Dimensions: 10-1/2"W x 13"D x 6"H
Weight: 14 pounds
Manufactured: Bell Punch Company, England, 1960s.

The Sumlock machines were updated again around 1960, with a more angular casing and a beige-and-grey colour scheme. This 9-column manual "FigureFlow" carries a "IVB" version number, but there were no significant changes to the mechanism.


Comptometer Model 9B Bell Punch Comptometer, Model 9B, S/N 701144 C
9/10 columns, single register, manual, decimal
Dimensions: 11"W x 13"D x 6"H
Weight: 14 pounds
Manufactured: Bell Punch Company, England, 1960s

This is the "Comptometer" version of the 9-column "FigureFlow" machine above.


Comptometer Model 12E Bell Punch Comptometer, Model 12E, S/N 524778C
12/13 columns, single register, electric, decimal
Dimensions: 13-1/2"W x 14"D x 7"H
Weight: 14 pounds
Manufactured: Bell Punch Company, England, mid-1960s.

This 12-column electric "Comptometer" was factory-built for decimal currency around the time of the Australian conversion.


Sumlock Duolectric Sumlock "Duolectric", Model 912, S/N 912/VZ/C/915,277
12/13 columns, dual register, electric, decimal
Dimensions: 13-1/2"W x 14"D x 8"H
Weight: 29 pounds
Manufactured: Bell Punch Company, England, 1960s.

A 12-column "Duolectric" machine in the late-model casing, factory-built for decimal currency.


Comptometer Model 12E Bell Punch Comptometer, Model 912/VZ, S/N 940089C
12/13 columns, dual register, electric, decimal
Dimensions: 13-1/2"W x 14"D x 7"H
Weight: 29 pounds
Manufactured: Bell Punch Company, England, late 1960s.

This is the "Comptometer" version of the 12-column "Duolectric" machine above. Note that both versions of this machine have a white "5" key in the third column (for reasons unknown), and both versions now have an electric fuse and a pilot light. The rear register is now controlled by a rocker bar instead of the sliding button.

Although labelled as a Comptometer, this machine carries a nameplate from Sumlock Anita Electronics (SAE) and a model number in the normal Bell Punch format. SAE was established by Bell Punch in 1966 to handle the electronic and legacy mechanical calculator business.


Sumlomatic Sumlock "Sumlomatic", Model 912/F/VIa, S/N 607,490A
12 columns (13 digits), dual register with multiplier, electric
Dimensions: 14"W x 15-1/2"D x 7-1/2"H
Weight: 35 pounds
Manufactured: Bell Punch Company, England, 1959-

The Version 6 "Sumlomatic" was the final development of the Bell Punch Company's mechanical calculators. It is based on the motor driven dual-register machine, with the addition of a third register and a control mechanism to perform semi-automatic multiplication. The concept is described in Webb's US Patent 2956741, filed in 1955, but the machine did not reach the market until 1959. The Sumlock "Anita" electronic calculator was announced in the following year.

The machine illustrated was originally built for Sterling currency, with the multiplier register covering the Pounds (ie, decimal) columns only. All-decimal machines with full-width multipliers were also made.
All-decimal Sumlomatic, from a book of tables dated 1959.



The Anita electronic calculator

The Bell Punch Company is generally credited with building the first production electronic calculator - the Anita - in 1961. The first Anita was a full-keyboard machine which was similar in form and function to the existing Sumlock mechanical comptometers, with the logic circuits based on cold-cathode vacuum tubes. A range of 10-key, all-solid-state machines (the 1000 series) was introduced in 1969, followed by an IC-based 1000-LSI series in 1971. IC-based pocket calculators were made from 1972 until the operation was disbanded by the new owners (Rockwell) in the mid-1970s.


Anita 1000 Anita 1000 Series, Model 1000, S/N 2335
Functions: ASMD
Technology: Discrete-component DTL, 5 IC chips
Display: 10 digits, Nixie tubes
Dimensions: 265W x 335D x 175H, weight 5.8kg
Manufactured: Bell Punch Company, England, 1969-72

This 10-key Anita Model 1000 is a basic 4-function machine which was made in England in early 1970. The machine is built almost entirely with discrete-component logic, using hundreds of individual resistors, diodes, and transistors. The components are mounted on a total of 20 circuit boards, each 230mm (9") wide by 2, 3, or 4" high.

Because of the very limited processing capability of these early machines, several manufacturers (including Anita and Hewlett-Packard) adopted the postfix (or "reverse Polish") logic system in order to simplify the internal circuit design. This system shares the workload by requiring the operator to enter the problem in a sequence that is more easily digested by the calculator. Although initially unfamiliar, the postfix system is entirely logical and rather elegant, and it aquired many supporters amongst scientific and technical enthusiasts. It was eventually abandoned in favour of "algebraic" logic as calculator capabilities improved, but is still widely used in some computer programming languages.


Anita 1011 Anita 1000 Series, Model 1011, S/N M2971
Functions: ASMD, constant, percent, roundoff, 1 memory
Technology: Discrete-component DTL, 7 IC chips
Display: 10 digits, Nixie tubes
Dimensions: 265W x 335D x 175H, weight 5.9kg
Manufactured: Bell Punch Company, England, 1969-72

The Anita Model 1011 is a similar but more capable machine which includes percentage calculations, 2-digit roundoff, and a memory or "Store" function. Other models were available with a square root function or an internal printer.


Anita 1011-LSI Anita 1000-LSI Series, Model 1011-LSI, S/N LM 107206
Functions: ASMD, constant, percent, roundoff, 1 memory
Technology: LSI, 5 IC chips
Display: 10 digits, Nixie tubes
Dimensions: 225W x 140D x 90H, weight 1.0kg
Manufactured: Bell Punch Company, England, 1971-

This Anita Model 1011-LSI from 1971 is functionally equivalent to the Model 1011 (above), but has been reduced to less than a fifth of the size and weight. The circuitry is based on five custom-built LSI (large-scale intergration) metal-can ICs from General Instruments Microelectronics. The distinctive styling incorporates the same full-size Nixie-tube display as the 1011, with a "wrap-around windscreen" borrowed from many of the cars of the 1960s.


Adler 84F Adler Financial Calculator, Model 84F, S/N 68.828.401
Functions: ASMD, percent, financial calculations
Technology: MOS-LSI (Rockwell A4561PB)
Display: 8 digits, vacuum fluorescent module
Dimensions: 75W x 120D x 20H, weight 200g.
Manufactured: for TA Vertriebs GmbH, Nürnberg, Germany, 1975

A range of Anita pocket calculators was designed and built in England from 1972. The same machines (with different colour schemes) were also supplied to Triumph-Adler in Germany, and were sold under both the Triumph and Adler brands. The sides and back of these Anita calculators are formed from a distinctive one-piece metal sleeve which slides upwards to open the battery compartment.

This Adler 84F from 1975 is a variant of the Anita 861 calculator for business and financial applications. In Algebraic mode it performs only ASMD and percentage calculations, with all results rounded to 2 decimal places. In Business mode it performs pre-programmed financial calculations involving prices, payments, and interest, with assistance from the Enter and Compute keys. The circuit boards appear to have been made in Japan, to a British design, for sale by a German company - but both the British and German companies were owned by Americans! (Triumph-Adler was owned by Litton Industries from 1968, and Sumlock Anita was owned by Rockwell from 1973).


Rockwell Model 18R Rockwell LED Calculator, Model 18R, S/N 354123
Functions: ASMD, percent, 1 memory
Technology: MOS-LSI (Rockwell B5000CC)
Display: 8 digits, NS LED module
Dimensions: 75W x 155D x 22H, weight 160g.
Manufactured: Assembled in Mexico for Rockwell International, Anaheim, CA, 1976

The 18R is one of a family of LED-display calculators produced by Rockwell under their own name in the mid-1970s, shortly before they abandoned the calculator business. The machine illustrated was assembled in Mexico using "US and foreign parts". Others are known to have been assembled in England at the former Sumlock Anita factory.

The circuit board uses a Rockwell B5000CC processor and an 8-digit LED display panel from National Semiconductor. The calculator draws only 7 to 30mA (270mW max) from a standard 9V battery mounted in the area above the display.



Resources for Further Information


Original text and images Copyright © John Wolff 2002-2022.
Last Updated: 6 March 2022.

Next:   Bell Punch Company labels and logos
Back to:    Home    Calculating Machines    Key-driven calculators