Abstract: A serial impact printer and including a single cam member for properly establishing and maintaining the throat gap distance between a character imprinting surface and the platen at a print point and for raising and lowering a selected ribbon, of a composite marking correcting ribbon pack assembly, to and from the print point. A short throat gap distance is needed for commercially acceptable printing speeds in this hammer mass printer, and is needed for high quality printing; conversely, a long throat gap distance is needed for print point visibility at all other times. The cam member has plural camming surfaces which coordinate ribbon position with throat gap distance.

Abstract: An impact mechanism for use in an impact printer, to deliver a printing force to drive a character element against a platen by means of a print tip movable toward and away from the platen. A rockable bail bar having an axis of rotation substantially parallel to the axis of the platen is constrained to limited angular movement toward and away from the platen by a prime mover connected to the bail bar. A push rod interconnects the print tip and the bail bar for delivering impact forces to the platen as the bail bar is moved toward the platen. The push rod is normally of a first length and rigid delivering impact forces to the platen and is collapsible to a second length, shorter than the first length, for drawing the print tip away from the platen so as to allow the character element to be removed. A collapsing mechanism is provided to convert the push rod from the first length to the second length.

Abstract: An anti-backlash double universal flexible coupling for providing positive and accurate angular positioning, constant rotational velocity and constant torque between an input driving shaft and an output driven shaft. The coupling includes universal pins supported by the driving and driven shafts and an intermediate coupling link comprising two coupling plates having bearing surfaces urged against the pins by a resilient element. The pins are maintained coplanar and parallel between the coupling plates.

Abstract: An improved print element shifting apparatus having a shifting cam movable in an arc for moving a rotatable print element between two positions by means of a shifting solenoid, and for reducing the mid-stroke peak load on the solenoid. A load modifying linkage arrangement is provided between the shifting solenoid and the shifting cam for imparting movement to the shifting cam alternatively from the one of two drive elements having the greatest mechanical advantage.

Abstract: Apparatus for adjusting a carriage assembly in a printing relationship to a platen. The carriage supports the printing mechanism including a print element. The distance between the carriage with the print element and the platen is adjusted by the adjustment apparatus, which rotates the carriage about a first support rail by changing the distance between the carriage and a second support rail.

Abstract: A serial printer for printing information on a record material is disclosed. The printer includes a frame and a platen mounted on the frame for rotation about its axis, the platen capable of supporting and advancing record material through the printer. A carriage assembly is also included and has a printing member supported thereon, the carriage assembly being supported for movement along a printing path adjacent the platen. Further, a motor is mounted on the frame and means are included for converting the rotary motion of the motor to movement of the carriage assembly along the printing path, the converting means including a cable mounted at either end to the frame. Additionally, means are included for maintaining a substantially constant tension on the cable, the tensioning means including means coupled to an end of the cable for automatically taking up slack in the cable caused by stretching or wear of the cable.

Abstract: Apparatus adapted for use in printers for indicating when the paper upon which information is to be printed has been depleted. A pivotable sensing member is slightly biased towards a fixed guide member, the two members being adjacent to one another. The sensing member has a horizontal row of protrusions on its inner wall which entend towards the opposing wall of the fixed member. The opposing wall of the fixed member similarly has a horizontal row of protrusions extending towards the sensing member but being aligned between the protrusions on the sensing member. In the situation wherein no paper is introduced between said members, a switch associated with the sensing member provides an indication to control circuiting that no paper is present for printing.