Strike and non-strike impact control mechanism for typewriter

摘要

A strike and non-strike impact control mechanism for typewriter comprises a drive shaft (4) equipped with at least two cams (8 and 9) corresponding to different strike forces, a tracker (13) of the contour of said cams, the movement of which is transmitted to a printing element (1), means (17 and 18) for displacement of said tracker (13), and means (20, 40 and 41) for receiving command impulses. So as to avoid the transfer of significant amounts of energy in the course of giving command impulses the mechanism comprises a tension spring (39) which acts upon the displacement means (17 and 18) so as to cause them to work in connection with an abutment apparatus (34-38). Said abutment apparatus (34-38) is controlled in various positions by said reception means (20, 40 and 41). A return apparatus (59 and 61) driven by drive shaft (4) returns displacement means (17 and 18) to a position known as normal following each complete rotation of said shaft (4).