Vendedor: pedroflb (0) 0%, Ubicación del artículo: Alicante, Comunidad Valenciana, Realiza envíos a: ES, Número de artículo: 282264690641 Condition: Calculadora mecánica Curta de los años 60, tipo I, usada sin golpes o daños, con caja metálica original (la caja si tiene algúna abolladura o raya)., Cantidad de unidades: 1, Tipo de unidad: Unidad, Detalles: The Curta is a small mechanical calculator developed by Curt Herzstark. The Curta's design is a descendant of Gottfried Leibniz's Stepped Reckoner and Charles Thomas' Arithmometer, accumulating values on cogs, which are added or complemented by a stepped drum mechanism. It has an extremely compact design: a small cylinder that fits in the palm of the hand.Curtas were considered the best portable calculators available until they were displaced by electronic calculators in the 1970s.The Curta was conceived by Curt Herzstark in the 1930s in Vienna, Austria. By 1938, he had filed a key patent, covering his complemented stepped drum, Deutsches Reichspatent (German National Patent) No. 747073. This single drum replaced the multiple drums, typically around 10 or so, of contemporary calculators, and it enabled not only addition, but subtraction through nines complementmath, essentially subtracting by adding. The nines' complement math breakthrough eliminated the significant mechanical complexity created when "borrowing" during subtraction. This drum would prove to be the key to the small, hand-held mechanical calculator the Curta would become.The Type I Curta has eight digits for data entry (known as "setting sliders"), a six-digit revolution counter, and an eleven-digit result counter. According to the advertising literature, it weighs only 8 ounces (230 g). Serial number 70154, produced in 1969, weighs 245 grams (8.6 oz).