This is a registration for a ‘Utility Model’ - a kind of patent-lite. It is one of a matching pair of such documents that appear to relate to Triplex derailleurs and date from April Fool’s Day 1959 (see also Spanish Utility Model # 66,252).
This one is titled ‘Mecanismo de Cambio de Velocidades para Bicicletas’ (which possibly translates as ‘mechanism for changing bicycle gears’). The other is titled ‘Dispositivo de Cambio de Velocidades para Bicicletas’ (which possibly translates as ‘device for changing bicycle gears’). It’s a subtle and beguiling difference that must have meant something to someone!