Bar-Lock typewriter (1939)
“Bar-Lock” typewriters were originally invented in US by Charles Spiro, a great typewriter pioneer, who had apprenticed in his father’s watchmakers shop, in New York. He was fascinated by a Remington typewriter, and at the end of 19th century he started patenting and producing his typewriters.
Around the beginning of last century, these typewriters were sold as the “Royal Bar-Lock” in England. In their advertisings they insisted very much about this typewriter being a British product, and it was quite successful in England, at the beginning of 1900 they said had been sold more than fifty thousands, a big number.
The “Bar-lock” name derive from the original invention of Charles Spiro. It was a system of alignment of the type bars, with a row of vertical pins in front of the platen, to reduce the clashing of the typewriter bars. But it was in the US models before 1900. You see now, in this British model, the bars are already standard, but it maintained the “Bar-Lock” name.
The “Bar-Lock” was the first typewriter to have the tabulator, back in 1895. You set the tabulation positions with these sliders in the back of the carriage. Then, when you press these buttons, the carriage stop in the positions you set up with the sliders.
If you want more information, you can see this video!

