GB1275495A - Printing device - Google Patents

Abstract

1275495 Selective printing NATIONAL CASH REGISTER CO 23 Sept 1970 [6 Oct 1969] 45247/70 Heading B6F Hammer impressiom mechanism.-A hammer 28 of glass-reinforced nylon material is supported by a pair of leaf-springs 31. The hammer carries at one end a metal impact member 41, and at the other end a self-lubricating plastics contact member 42. A "pigtail" spring 29 passes through member 42 and is embedded in the hammer body material. The spring 29 engages a boot 22 on a solenoid arm 17 which initiates movement of the hammer when solenoid 54 is energized. The solenoid arm 17 rests on a back stop device 24, and a penetration control device 55 is provided having a stop member 45 which engages a surface 32 of the hammer to control the length of the printing stroke. During operation, the solenoid arm 17 moves a set distance, whereafter the hammer continues under its own momentum thereby stretching the "pigtail" spring 29. After printing and before the solenoid arm 17 has returned to its rest position, the "pigtail" spring has the effect of re-engaging the hammer with the solenoid arm. Kinetic energy is absorbed by the resilient energyabsorbing stop members 33 and 39 adapted to engage the leaf-springs, stop member 45, backstop device 24 and contact member 42. In addition, kinetic energy is absorbed by a regenerative system comprising the solenoid coil in combination with a diode and resistor connected in series across the coil. Specification 1,275,493 is referred to.