Abstract: The impact tip of the print hammer is provided with a curved face in one direction and shaped in a cylindrically-arcuate configuration. The impact tip is formed with the surface curvature in a direction perpendicular to the direction of character height and in a convexly curved or rounded manner as viewed from the type character. This structure of the impact tip together with an optimum chamfer angle of the type character permits closer spacing of the characters.

Abstract: A cassette contains a pair of endless printing ribbons on separate spools, each ribbon having an independent drive with a mechanism provided to enable shifting from one drive to the other, thereby permitting selection of one or the other ribbon.

Abstract: A frame member carries a single piece which provides the several functions of locating, retaining, and bearing a grooved shaft or like member and wherein the piece includes an internal ring for mating with such grooved shaft.

Abstract: A pair of compensating wheels are carried by a print head carriage in position to ride on record media being printed and are rotatably driven by frictional contact therewith, the wheels having overriding clutches associated with their respective shafts to permit driving of one shaft and its gear in alternate manner with the other shaft and its gear. The respective driving gear engages with a driven gear on a third shaft for rotation thereof and thereby drives the ribbon in one direction. Upon return of the print head carriage in the opposite direction, the action of the overriding clutches is reversed to permit driving of the other shaft while the first shaft and its wheel are free wheeling. Regardless of the direction of travel of the print head carriage, the ribbon drive shaft is rotated in the same direction.

Abstract: A back-up member is provided wherein a single bracket supports an elongated member at several points therealong, one face of the elongated member serving as a flat surface for a plurality of resilient pads which are positioned to be formed in a curved manner by a spring member which is adjacent slant-edged portions of the bracket and secured at the several points thereof. The spring member thereby presents a pair of surfaces for applying pressure on record media to maintain such media in close proximity to associated read and write heads.

Abstract: A drive roller and cooperating idler rollers of the friction type are combined to transport or to advance paper or like record media wherein the idler rollers are driven slightly faster than the drive roller. The drive roller has slots or voids in the periphery thereof aligned with the path of travel of the idler rollers to permit an easing or relaxing of the idler roll pressure on the paper and thereby enable the canceling of any accumulated difference in the drive motion between the drive roller and the idler rollers.

Abstract: A prime mover is connected to a drive train in a printer to provide incremental or intermittent motion to the paper and to the hammer bank in a time sharing manner wherein the output of a closed loop control mode having a switching amplifier and a feedback circuit utilizing pulse width modulated signals operate the system under static conditions. The drive train includes the use of a planetary gear head and electro-magnetic friction brakes for transducing the output from the prime mover to the two loads. Alternate transducing means include the use of two clutches, or a planetary gear head and band brakes.

Abstract: A code made up of wedge-shaped elements representative in binary code for character reading of information. The area covered by the wedges is equivalent to selected printed characters and the reading is accomplished by a scanner which is pulsed at precise intervals or which is dynamic in operation, i.e. continuously reading or sensing the wedge as the scanner or the code is moved in a direction from one to the other end of the wedge in either an increasing or a decreasing area thereof. The scan profiles of the wedges are indicated during continuous reading thereof or from the reading or sensing thereof at precise points therealong and such profiles are then changed into transition profiles to determine polarity of change in timing or position of the information.

Abstract: A locking mechanism of the cylinder type for a business machine wherein four different keys can be accommodated in a single lock to perform various functions or modes of operation. The mechanism includes ring members and locking pins operably associated with the cylinder and with the lock body either to permit or to restrict rotational movement thereof with respect to the ring members. Rotation of a key in the cylinder to a predetermined limit sets up a switching arrangement to provide a signal for each mode of operation desired to be accomplished.