Patent GB-259470-A (GB)
Abstract: 259,470. National Cash Register Co., Ltd., (National Cash Register Co.). March 25, 1926. Hammer - impression arrangements for cash registers, calculating-machines, and the like. In hammer-impression arrangements of the kind comprising a hammeractuator connected to a spring and adapted to be retracted and released by a rotary cam, the hammer on return to normal position is positively arrested and is thereby prevented from being caused to rebound by the actuator. In the arrangement shown in Fig. 1, the hammer 5U rocks on a shaft 42 and has a pin 63 normally abutting on the end of an arm 62 of a rocking member 61 having pin-and-fork engagement with an actuator 51 connected to a spring 55. A finger 52 on the actuator abuts on a rocking yoke 41 having an arm 39 connected by a link 36 to a bell-crank 35 operated by a rotary cam 31, the spring 55 normally maintaining the arm in contact with a stop 70. When either of the cam lugs 32, 33 engages the bell-crank, the yoke rocks the actuator, the spring 55 is stretched and a spring 64 depresses the hammer, the pin 63 riding on the arm 62. On release of the bell-crank, the spring 55 returns the actuator and the member 61 propels the hammer for impression. The hammer is returned by the spring 64, aided by the resilience of the platen 200, and is arrested by the pin 63 striking the end of the arm 62, the impact being received by the pivot 67 of the member 61. The hammer is thereby prevented from reacting on the actuator and being caused to rebound by the spring 55. In a modification the member 61 is pivoted on the rod 56 and the pin 63 is near the platen, the member being rocked in one direction by a long arm on the actuator and being returned by the spring 55. In another arrangement the hammer is driven directly by the actuator, a shoulder thereon engaging the pin 63, and the member 61 is rocked in one direction by a pin on the actuator and is returned by the hammer-returning spring; or the member may be rocked in both directions by the actuator, the member and actuator having pin-and-fork engagement. In the arrangement shown in Fig. 8, the hammer 50 has a pin 98 for engaging the actuator 51, and a pin 97 normally engaging a spring-urged latch 95 pivoted on the framework and having a tail 96 abutting on the yoke 41. When the actuator is rocked, the latch after restraining the hammer is released and the spring 64 depresses the hammer until the pin 98 engages the actuator. The stretched spring 55 then returns the actuator and the hammer is rocked. On return of the hammer the pin 97 engages the latch, the impact being received by the pivot 94, and the hammer is thereby prevented from reacting on the actuator. In the arrangement shown in Fig. 9, a series of hammers 50 are provided with pins 163 in the path of the actuators 51, engagement being prevented by a rod 98 which extends under the hammers. The rod is carried by rocking arms 99 connected by a link 101 to a rocking arm 102 having pin-and-slot engagement with a member connected to the yoke 41. When the actuators are rocked to stretch the springs 55, the rod moves away from the hammers, and the hammers are depressed by springs 64. The springs 55 then cause the actuators to rock the hammers, the rod returning to normal position. On return, the hammers are arrested by the rod and are thereby prevented from reacting on the actuators. In the arrangement shown in Fig. 12, the hammer 50 is provided with a counterbalanced latch 108 having a lug 109 normally held by a light spring 110 in contact with an arm 251 on the actuator 51, the arm engaging also a pin 263 on the hammer. On return of the hammer after impression the lug 109 strikes the arm 251 in advance of the pin 263, and the latch turns clockwise and brings a tail 112 thereon into engagement with a face 113 on the arm, the hammer being thereby temporarily locked to the actuator and prevented from rebounding. The latch 108 may be replaced by a pivoted disc having a stud for engaging the actuator and a lug for engaging a face thereon. In the arrangement shown in Fig. 15, the actuator 41 has an arm 751 provided with a stud 119 engaging the hammer 50, a counterbalanced pawl 118 pivoted on the stud being provided with a pin 120 engaging a slot 121 in the hammer, and a pin 123 held by a light spring 125 in contact with the hammer. On return of the hammer after impression, the hammer strikes the pin 123 in advance of the stud 119 and the pawl is rocked clockwise carrying the pin 120 to the right-hand end of the slot and temporarily locking the hammer to the actuator to prevent rebound.