Abstract: The invention concerns a shift mechanism for typewriters having a carriage in which the shift instruction is transmitted by two distinct interlocks of which one is in an active position when the other is in an inactive position. Each interlock is controlled by a primary lever and an auxiliary lever which causes it to work in connection with drive means serving to place it in an active position. A stirrup-shaped pivotal part is provided with two principal elements, one of which comprises the auxiliary lever controlling a first one of the interlocks, and the other element comprising an arm capable of being driven by the second interlock, the latter being normally controlled by the primary lever connected to a key on a keyboard.