Abstract: 4. In a telegraph system, interconnected stations, converters at each station comprising transmitting and receiving apparatus, a signal line connected to said stations, said transmitting apparatus comprising a series of cam controlled transmitting contacts, means for controlling said contacts permutably, and means for altering the control imparted to said contacts by said means, said receiving apparatus comprising a selector mechanism responsive to enciphered signals generated by any transmitting apparatus, and means for retranslating said altered signal to effect printing in correspondence thereto, an electromagnetically controlled ciphering device at each station, and pulsing means cyclically operable by said receiving apparatus for controlling said ciphering device, whereby said altering means is rendered effective.

Abstract: The elements of a drive assembly for punched paper tape are arranged in a fixed relation on a shaft (42) to which the paper feed wheel (70) is attached. The assembly includes a drive mechanism (25 or 27) for selectively imparting equal increments of rotational motion to the shaft, first and second ball bearing assemblies (65, 75), spacers (74, 68, 69) and a nut (76). The shaft assembly is slidable within holes in the frame sideplates (71, 73) and within curved surfaces of projections (66, 67) of the paper guide body (28).

Abstract: An apparatus for damping the acoustical impact noise traveling along a length of paper as it passes through a printer including resilient urethane foam rollers in engagement with a large proportion of the width of the paper with a pressure damping roller depressing portions of the paper deeply into engagement with the resilient roller to enable the resilient roller to damp acoustical energy traveling along the length of the paper.

Abstract: A paper guide extends around the platen of a printing machine and has a flexible extension which bears against the front of the moving printing mechanism included in the printing machine. The close proximity of the paper guide to the printing mechanism of the printing machine serves to guide the paper as closely as possible into the small gap between the printing head and the platen and also to guide the paper as accurately as possible out through the paper-exit opening of the cabinet of the printing machine. Being so closely guided (particularly in the case of multiple sheet carbon set-ups or the joints of fan-fold paper), the leading edge or a fold of the paper is less likely to catch on the ribbon or get caught on the edge of the paper-exit opening of the cabinet. The flexible final guide extends so high up the printing mechanism side of the platen that it actually bears against the printing head and is flexibly deflected by the printing head as the printing head moves across the front of the platen.

Abstract: A re-entrant shift register comprising eight levels and in the illustrative embodiment eight stages per level, is selectively used in the buffering of information between an asynchronous signal source, e.g., a manual keyboard and a data sink, e.g., a controller which accepts information upon an asynchronous basis. Information to be transmitted from a data source to the data sink is entered in parallel in a register in the form of a latch under control of write control circuitry. Similarly, data to be transmitted to the asynchronous data sink is temporarily stored in a parallel output register in the form of a latch. The writing of information into and out of the output latch is under the control of read control circuitry. The write control circuit includes a write counter and the read control circuit includes a read counter.

Abstract: In a cartridge for an endless typewriter ribbon, a fresh ribbon is stored in the cartridge with a substantial length of ribbon wound in a convolute around a roller. When the cartridge is mounted in a printing apparatus, the ribbon is drawn from the cartridge, exhausting the convolute. When the cartridge is fully mounted in position in the printer, a single path of ribbon extends into the cartridge and through an opening along a chord of the roller and out from the cartridge. A brake is provided to limit motion of the roller so as to preclude premature unwinding of the convolute and to limit oscillation of the roller during operation of the printer. With the normal operating path of the ribbon extending through the chord-oriented slot of the roller, ribbon can readily be rewound onto the roller upon removal of the cartridge from the printer.

Abstract: In laser recording systems, data is written in a thermoplastic medium and a smooth surface of the medium is critical for high quality operation of the system. This smooth recording surface is provided by spin coating the supporting substrate, which may be an unpolished metal, with an intermediate layer of thermosetting material which is nonconformal in nature. The thermoplastic medium which is conformal in nature is then spin coated onto the smooth surface provided by the intermediate layer to form a microscopically smooth conformal layer.

Abstract: A variable reluctance motor wound for two-phase excitation is excited with single phase pulses, whereby the de-energization of one phase coil aids in the energization of the succeeding (and preceding) phase coil, in which a phase coil that is about to be de-energized is energized for a short period with maximum excitation energy power in order that the decay from that maximum power level, upon advance of the stepping motor, induces, by transformer action, an aiding voltage in the next succeeding phase coil so as to increase the speed of excitation of that next succeeding phase coil.

Abstract: In order to advance an inked ribbon in a printing apparatus in which a printing carriage mechanism moves across the width of a platen, one-way brakes are placed on ribbon guide rollers on the printing carriage mechanism to permit relative movement between the printing carriage mechanism and the inked ribbon as the printing carriage mechanism is advancing from left-to-right across the paper. One-way brakes are placed on return rollers in the ribbon path in order to prevent the inked ribbon from moving with respect to the platen as the printing carriage mechanism is moving from left-to-right across the paper. When the printing carriage mechanism moves from right-to-left in order to return to the left-hand margin, the one-way brakes on the ribbon guide rollers on the printing carriage mechanism apply substantial friction to the inked ribbon and drag the inked ribbon with the printing carriage mechanism as the printing carriage mechanism returns from right-to-left.

Abstract: A paper web is maintained on a rotating apertured drum by means of a vacuum created inside of the drum. The paper length is slightly greater than the circumference of the drum thereby providing a tangentially projecting flap which is detected by a flap sensor. The concurrance of a pulse from the flap sensor with an end of message signal enables a counter. A first series of selected states of the counter are decoded and used to interrupt the vacuum causing the paper to come to rest against a shroud surrounding the drum. A second series of counter states, some of which coincide with the first series, open a discharge door covering a paper discharge opening in the shroud. When the vacuum is reapplied to the drum, upon expiration of the first series of counter states, the rotating drum boosts the paper out through the discharge opening.

Abstract: A circuit is described for selectively increasing the number of text rows on the display screen of a CRT. The number of scan lines in each text row is reduced by one in response to a display format selection signal. The scan lines so saved are utilized to form two additional text rows. A variable modulus scan line counter is used in combination with a decoder to provide the scan line counter modulus desired. Additionally, a text row counter is used in combination with a second decoder to selectively change the modulus of the text row counter to correspond with the selected modulus of the scan line counter. A compressed display is provided by simultaneously changing the modulus of both the scan line and text row counters.

Abstract: A printing apparatus having a moving carriage with a snap action switch mounted thereon to initialize the left and right margins of the printing apparatus. The carriage is moved to the left until the snap action switch strikes a stop on the frame of the machine. The carriage is then moved a predetermined distance to the right, and a left margin counter is set to zero while a right margin counter is set to a count representative of the width of printing between margins. The counters are incremented and decremented by movement of the carriage with the zero point of each counter representing presence of the carriage at that associated margin. Manual devices are provided for setting a narrower printing field with wider margins at either side by resetting the margin counters. Also, a margin release allows movement of the carriage outside of the narrowed printing field but never outside of a maximum printing field.

Abstract: A guide system for arranging a plurality of print wires from a converging arrangement into a parallel arrangement aligned with a column of dot locations to be printed on a record medium, the guide system including a first guide more remote from the record for bearing against the wires as they are bent into a direction perpendicular to the record medium. And a second guide nearer the record medium than is the first guide, for applying the bending force to the wires to bring them into alignment perpendicular to the record medium. A final guide still nearer to the record medium finally assures that the wires are in a straight, columnar line as they face the record medium.

Abstract: A two-phase, non-overlapping clock signal is generated in response to a single-phase input clock signal by delaying the input clock signal to produce the first phase output clock signal (.phi..sub.1), producing a delayed signal from the first phase clock signal, and gating the further delayed first phase clock signal with the input clock signal to produce an inverted signal for a second phase clock signal (.phi..sub.2), in order to produce gaps between the trailing edge of one phase of the output clock and the leading edge of the other phase of the output clock signal in order to accommodate dynamic transient conditions that must occur in a following utilization circuit between successive phase clock pulse signals.

Abstract: A carriage for positioning a print mechanism in front of a record medium and moving the print mechanism back and forth in front of the record medium with facility for retracting the print mechanism to permit insertion of a ribbon and biasing the print mechanism forward toward the record medium against an adjustable stop. The retracting mechanism being further adjustable for retracting the printing mechanism completely out of the carriage for removal therefrom.

Abstract: A supply spindle for a cassette recorder which includes means for reducing the abrupt start-up forces to which the recording tape within the cassette is subjected by incrementally coupling the inertial mass of the supply spindle to the tape upon start-up. The supply spindle includes a shaft carrying a supply head for engaging a cassette spool. The supply head is axially as well as rotationally movable upon the shaft. A coil spring, fixed to the shaft and supply head, urges the head to the end of the shaft. Additionally, the spring rotatably biases the supply head against a stop carried on the shaft. Initially upon start-up, only a portion of the mass of the supply spindle is coupled to the magnetic tape with the full mass being subsequently coupled thereto.

Abstract: A circuit is described for controlling a programmable logic array adapted for use with a communications terminal. The logic array includes an input AND-section defined by a plurality of addressable fields and an output OR-section. One field of the input section is addressed by an incoming address register selectively loaded with incoming data. A second field is addressed by a branch address register loaded with selective outputs of the output section thus providing program branching capabilities. Also, a loop counter and a clocked program counter address two additional fields of the input section. The loop counter facilitates program looping in the logic array while the program counter affords real time operational characteristics for the control circuit.

Abstract: A stepping motor is described having two operative modes, the first mode being a normal rotary mode and the second a stationary mode. During rotary operation, the induced energy created by interruption of the current flow through the energized phase winding is dissipated quickly by a zener diode connected across the winding. In the stationary mode, a pulsed current is fed to one of the phase windings of the motor to assure stationary positioning of the rotor. During stationary operation, the zener diode is shunted with a second conventional diode providing a low impedance path to the current induced in the phase winding upon de-energization. This low impedance path greatly reduces the energy dissipated during the off condition of the pulsed current thereby greatly reducing motor power requirements during stationary operation.

Abstract: In order to avoid ribbon rollover in a high speed impact printer, a crown roller, having a crown offset from the roller's center, is used to guide the ribbon. The crown tends to center the ribbon about itself and the roller is dimensioned so that the distance from the crown to the end flange of the roller is sufficiently far that under all operating conditions the ribbon will remain separated from the flange and hence will avoid rollover. In particular the roller is positioned so that the print head will initially impact the advancing ribbon off center toward one edge of the ribbon. As printing continues, this repeated impacting will cause that edge of the ribbon to wear, the result being that the tension across the ribbon will decrease and the crown roller will constantly reposition the ribbon as if it were of an ever decreasing width.