A Tour of Company Sites

Plus & Sumlock Mechanical Calculators
PLUS 509/Y Imperial-Weight Calculator
PLUS 509 Imperial-Weight Calculator

Plus model 509/Y Imperial-Weight abbreviated "Comptometer".

This is a direct action keyboard calculator of the "comptometer" type with an abbreviated keyboard for calculations in Imperial weight units.

241 x 182 x 177 mm (9.5" x 7.2" x 7.0").

Made by Bell Punch Co. Ltd. in England, distributed in U.K. by Sumlock Comptometer Ltd.

The machine illustrated has serial number 509/Y/876.514, and has the angular style casing which was introduced in 1958.

This machine has an abbreviated keyboard - it only has keys 1 to 5 in the standard decades columns, so to enter a number greater than 5 you have to press one key followed by another which add up to the number required. Compare it with the slightly different 509/SP weight calculator.

The machine in the photographs is displaying the total of 1 Ton, 19 Hundred-weights, 3 Quarters, and 27 Pounds.
Keyboard

Close up of the keyboard of this imperial-
weight calculator.
Keyboard
Inside

With the cover removed. The standard, decimal columns use plastic gear wheels, while the non-standard columns use metal gears. It was probably not economical to make the moulds for these non-standard items
Inside

With the cover removed, from the rear.

Fortunately, Britain changed to the metric system during the 1970s and 1980s and this complicated system of units is now virtually obsolete. It does not appear to have been used in modern times in the U.S.A. where weights are customarily given in Pounds (lbs) only.

No electronic calculators are known to have been sold which use this weight system, though a Sumlock-Anita engineer says that he was involved in the modification of some Anita electronic calculators to this system for Britain's National Coal Board in the late 1960s.
Home
Introduction
Origins of Bell Punch Co.
Mechanical Calculator Days
National Calculating Service
Development of Anita 1
Development of Anita 2
Anita is Launched
At work with Anita
All Change at Bell Punch
Anita Developed Further
Anita at its Zenith
The Rockwell Connection
Demise of Anita & Bell Punch
Mechanical Calculators
Early Anita Desktop Calculators
Transistors & Integrated Circuits
Anita LSI Desk Calculators
Anita Hand-held Calculators
Rockwell-Anita Calculators
Calculators made by others
Advertisements & Brochures
Operating Manuals & Materials
Company Information
A Tour of Company Sites
Summary
The Technology Explained
Operating a Comptometer
Old Sterling Currency, £sd
Links
Update Information
Getting in touch

Plus & Sumlock Mechanical Calculators
Plus Adder S
Plus Adder SJ
Plus Adder ST
London Computator 509/S
London Computator 912/S
Plus 506/D
Plus 506/F
Plus 506/T
Plus 509/D
Plus 509/F
Plus 509/S
PLUS 509/SP Weight Calculator
PLUS 509/T Time Calculator
PLUS 509/Y Weight Calculator
Plus 512/S
Sumlock 912/F
Sumlock 912/S
Sumlock 912/Y Weight Calculator
Sumlock 913/S with Certopost
Sumlomatic
Sumlock Comptometer 993m
Sumlock Comptometer 993s

Click here to go to the Vintage Calculators Web Museum

Text & photographs copyright © 2002 - 2009 Nigel Tout, except where noted otherwise.