GB968185A - High speed printing mechanism - Google Patents

Abstract

968,185. Selective printers. NATIONAL CASH REGISTER CO. Aug. 22, 1963 [Sept. 14, 1962], No. 33205/63. Heading B6F. A high-speed printer comprises a plurality of continuously rotatable type wheels 11, Fig. 1, a corresponding plurality of hammers 25. associated with interposers 40 adjacent the hammers and lying out of a path of a plurality of hammer drives 20, mounted on hammer drive assemblies rotating in synchronism with the type wheels and a selectively operable electromagnet 36 rendered effective to cause the interposers 40 to be positioned in the path of the next available hammer drivers 20 to be struck thereby to actuate the associated printing hammers 25. In operation when a character to be printed has been selected the electromagnet 36, having a number of coils, has a dropout coil (not shown) energized to counteract the magnetic force of a holding coil so that the magnetic field will decay and allow a spring 43 to move the armature 37 counter-clockwise against a stop-bar 35 and bring the interposer 40 into the path of a selected hammer driver 20. The driver 20, which is pivotally mounted between a pair of discs 18 mounted on a shaft 17, rotating synchronously with the type wheels, rests on a stop surface 24a of a radial lobe 21 and engages the lower interposer 40, Fig. 4. The energy from the driver 20 is then transferred to the printing manner 25 through the interposer carrier 30 to drive the hammer into impression position (Fig. 5, not shown). The impact of the hammer can be adjusted by an eccentrically mounted impact control stop-bar 49. As the hammer driver 20 proceeds in its circular path about the shaft 17, it is pivoted clockwise about its pin 23 until it comes to rest against a second stop surface 24b in which position it has moved the interposer 40, upwardly (Fig. 6, not shown), causing the armature 37 to be lifted against a stop-bar 47 so that the re-established magnetic field of the magnet 36 may restrain the armature 37. Simultaneously the hammer is restored under the action of spring 27, which also moves indirectly the interposer carrier 30 against the stop surface of the bar 35. As the hammer driver 20 leaves the bifurcated end of the hammer 25, the driver 20 is restored under the action of centrifugal force to the original position in which it rests against the stop surface 24a.