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of Bar-Lock Works, Basford, Nottingham. Telephone: 75141-2. Cables: "Barlock, Nottingham". As Bar-Lock (1925) Co. (1929)
Ditto Address and Telephone. Cables: "Bar-Lock". As Bar-Lock Typewriter Co. (1947)
1880s Invented by New York watchmaker Charles Spiro, the Barlock offered visible writing by mounting its typebars vertically between the typist and the carriage. It was manufactured in the United States by the Columbia Typewriter Manufacturing Co.
The name Barlock was derived from the typebar locking mechanism designed to insure proper alignment at the printing point. This device was nothing more than a set of pins that would allow only one key to enter it at a time, thus avoiding typebar crashing. Additionally, the Barlock offered a double keyboard and ribbon inking. Early models were equipped with ornate shields covering the typebars while later models used a more modest version.
1888/9 The machine was first advertised.
Eventually, production was established in England.
1914 The business was sold entirely to the British subsidiary, known as Barlock Typewriter Co. The First World War intervened, but production resumed afterwards.
1915 Front strike designs were prepared, beginning in 1915, and were finally perfected in 1921.
1919 Patent - Improvements in or relating to typewriter bases. 
1919 Patent - Improvements in or relating to type-bar mechanisms. 
By 1925, the company was in dire straits, and with heavy investment by Sir John Jardine, was reorganized as Bar-Lock (1925).
1929 British Industries Fair Advert for the 'All-British' Bar-Lock Typewriter and Interchangeable Carriages. New Model Invoicing Machines with ten key-set tabulators; Pin Point Machines for Cheque Writing. By appointment to His Majesty King George V. As Bar-Lock (1925) Co. (Stationery Section - Stand No. R.149) 
WWII. Production stopped again for the Second World War, again resumed, but the company was in trouble once more.
1947 British Industries Fair Advert for Post War Model No. 21 Standard Typewriter with Interchangeable Carriages. Carbonless Continuous Stationery Attachment. Also Bar-Lock Four-Bank Portable Model and "Family" No-Shift Portable Model with single Gothic Characters for Universal Use, and Bar-Let Three-Bank Portable. As Bar-Lock Typewriter Co. (Office Machinery and Equipment Section - Olympia, Ground Floor, Stand No. B.1401) 
1953 Further investment led to the company becoming Byron Business Machines, which stopped production two years later. Byron attempted to design a totally new machine, which met with great trouble.
1958 Byron sold its entire office machine business to the Oliver Typewriter Manufacturing Co.