Abstract: A unitary cassette for a typewriter comprises a container and two arms. The container comprises two support elements and which project from the bottom and which are capable of rotatably supporting a supply spool and a take-up spool for a correction ribbon. Two guide elements projecting from the ends of the arms guide a portion of the ribbon below the typing ribbon, and a tensioning device holds the ribbon taut. The cassette can be mounted on a carriage of the machine by means of two projections projecting from the underneath of the bottom and which are capable of being pivotally mounted in two respective grooves and moving against two co-operating surfaces for oscillating movement about an axis parallel to the roller. A pin on one side of the container can be removably engaged into a seat of a connecting lever of the machine, which is connected to a displacement means.

Abstract: A cassette for a printing ribbon for typewriters comprises a casing accommodating a supply spool, a receiving spool and a brake and take up device which operates on a tube of the supply spool and on the ribbon which is unwound from the supply spool. The tube is rotatable on a sleeve projecting from the bottom of the casing. The brake and take up device comprises a shoe for applying a braking action to an internal surface of the tube. A wire spring has an intermediate portion which engages in a seat of coupling means of the shoe. In a first position the shoe is urged against the surface of the tube and brakes the supply spool. In a second position the shoe is spaced from the internal surface of the tube and the supply spool is free to rotate. The spring also performs the slack ribbon take-up function and for that purpose comprises an end having an L-shaped bent portion which in turn is engaged with the ribbon to regulate the tension and unwinding of the ribbon which is unwound from the supply spool.

Abstract: The paper pressing arrangement comprises a paper guide plate for guiding a sheet of paper around a platen roller towards the typing line. The paper guide plate comprises two conveyor modules each of which supports three paper pressing rollers and is provided with a pivot element projecting from the barycentre of the triangle joining the mid-points of the three rollers. A control mechanism, in an operative position, transmits by means of a rocker lever pivotally connected to the pivot elements the action of a spring to urge the conveyor modules against the roller. The control mechanism comprises a lever for positioning the two conveyor modules in an inoperative position to permit insection of the sheet of paper. Each conveyor module defines a first axis for rotation of two front paper pressing rollers and a second axis spaced from the first axis for rotation of a rear roller disposed intermediate each pair front rollers.

Abstract: The contact-type keyboard comprises a plurality of keys which are movable from a rest position to an operative position and which each have a sleeve capable of being accommodated in a tube provided on the upper part of a dome portion of elastomeric material. Each dome portion projects from a mat and, below the tube, comprises an internal circular ring provided with a movable conductive portion for short-circuiting a corresponding fixed conductor of a printed circuit which in turn is carried by a stop plate of insulating material. Each sleeve is of such a length as to pass internally by way of an upper opening through the dome portion, to engage a through hole in the plate to project downwardly beyond the plate and comprises a seat capable of accommodating a corresponding pin of a support frame structure so as to guide the respective key from the rest position to the operative position and vice-versa.

Abstract: The correction device is applied to an electronic typewriter with a daisywheel and comprising an electric selector motor which selectively rotates the character-carrying daisywheel in the clockwise and the anti-clockwise directions for selecting the characters to be typed and/or corrected, a carrier for a correcting ribbon and a control member for lifting the carrier and permitting correction of the typed characters. A small correcting solenoid can be activated to couple the control member of the correcting ribbon to the selector motor. The control unit controls the motor and the solenoid in such a way that the selector motor can also actuate the control member in each correction cycle for positioning the correcting ribbon in front of the typing point. In the illustrated form, the solenoid unlatches a lever which drops to bring the control member into mesh with a gear on the motor shaft. The control gear is eccentrically mounted on the lever and a first 180.degree. revolution, corresponding to 360.degree.