Strike and non-strike impact control mechanism for typewriter

Claim 1

Strike and non-strike impact control mechanism for a typewriter having a printing element (1) movable parallel to a platen (3) upon a carrier (2), said mechanism comprising particularly a drive shaft (4), at least two rotatable cams (8 and 9) integral with the drive shaft and corresponding to different strike forces, a guidance component (17 and 18) for guiding a tracker (13) of the radial contour of said cams (8 and 9), and capable of displacing said tracker so as to cause said tracker to work in connection with one or the other or neither of said cams, means (14-17) for transmission of the movement of said tracker (13) to said printing element (1) to assure particularly the striking of a character, and means (20,40 and 41) for receiving command impulses given by universal bars (26,42 and 43) arranged parallel to said platen (3), characterized in that said control mechanism comprises abutment apparatus (34-38) for abutting said guidance component (17 and 18) of said tracker (13) in several positions, the activation of said apparatus being controlled by said means (20,40 and 41) for receiving command impulses, a tension spring (39) acting upon said guidance component (17 and 18) of said tracker (13) to cause said means for receiving command impulses to work in connection with said abutment apparatus, a return apparatus (61 and 59) for return of said guidance component into a normal position, said return apparatus being driven by said drive shaft (4) upon each complete rotation of said drive shaft, said means for receiving command impluses comprising first, second and third intermediate couplers (20,40 and 41), said abutment apparatus comprising a key (38), the position of which is controlled by said second and third intermediate couplers (40 and 41) for receiving command impulses, and by an extremity (37) of a lever (34) driven by said guidance component (17 and 18) of said tracker (13), and set up so as to work in connection with said key (38) in several positions corresponding to the choice of strike or non-strike force.