Patent GB-465849-A (GB)
Title: A nought-entering mechanism for "ten key" adding machines
IPC: G06C7/10
Filed: 1936-03-19
Abstract: 465,849. Calculating - machines. AARNI, H., and KEMILA, J. H. March 19, 1936, No. 8224. [Class 106 (i)] A ten-key machine having a pin carriage is provided with means whereby a digit key and the nought (0) key may be depressed simultaneously and the carriage moved to register the digit and the nought in the proper sequence. A two-noughts (00) and a three-noughts (000) key may also be provided. One or both of the keys 00 and 000 may be depressed with a digit key or with a digit key and the 0 key, the carriage being moved in each case to register the digit followed by the number of noughts corresponding to the depressed keys. A bridge 8, Fig. 16, overlies all the levers 5 of the digit keys 9 and is connected to a ratchet pawl 27 to rock this pawl anticlockwise, Fig. 1, when a -digit key is depressed, the pawl cooperating with a ratchet wheel 23. A bevel wheel 20 is pivoted in the ratchet wheel 23 and engages bevel wheels 17, 16 the latter being integral with a ratchet wheel 14 meshing with a rack 32 on the pin carriage. The 00 key 10, Fig. 16, is connected to a pawl 28 similar to the pawl 27 and co-operating with a ratchet wheel 24 in which is pivoted a bevel wheel 21 engaging the bevel wheel 17 and another double bevel wheel 18. The gearing is such that when the ratchet wheel 24 is released for one step the pin carriage ratchet wheel 14 moves through two steps to register the two noughts, corresponding to the key 00. The 000 key 11 is connected to a pawl 29 controlling a ratchet wheel 25 in which is pivoted a bevel wheel 22 engaging the bevel wheel 18 and another bevel wheel 19 whereby, when the wheel 25 is released for one step, the wheel 14 moves through three steps. Finally, the nought (0) key 9 controls through a pawl 30 a ratchet wheel integral with the bevel wheel 19 and so toothed that one step of movement corresponds to one step of the ratchet wheel 14. The various bevel wheels comprise a differential gear whereby, when a digit key and one or more of the nought keys 0, 00, 000 are depressed simultaneously, the ratchet wheel 14 receives one step of movement from the digit key plus a number of steps (from one to six) from the keys 0, 00, 000. The pawl 28 is shown inverted in Fig. 9 and has a rigid tooth 28a and a pivoted tooth 28b, urged by a spring into the position shown. The teeth of the ratchet wheel 24 co-operating with the pawl 28 are normally held by the pivoted pawl tooth 28b and turn this tooth against the action of its spring into alignment withthe rigid tooth. When the pawl is rocked the pivoted pawl tooth 28b is free to spring into the position shown in Fig. 11 and the ratchet wheel tooth is held by the rigid pawl tooth. When the pawl is released, the next ratchet wheel tooth comes against the pivoted pawl tooth and, on account of the spring pressure urging the pin carriage to the left, the pivoted tooth is moved against its spring into alignment with the rigid tooth and the ratchet wheel moves to allow the carriage to make one step. The carriage is held against movement by a pawl 33, Fig. 1, until all depressed keys have been released, the pawl engaging . the carriage rack 32 and being actuated by a bar 31. Pins on the pawls 27 ... 30 pass through slots in this bar and the bar is thus held raised to lock the carriage as long as any key is depressed. The nought stops 3, Fig. 16, are initially in operative position in each denomination and the corresponding nought stop is pushed down when a digit key is depressed by a member 7 connected by a lever and link to the bridge 8 overlying the digit-key lever 5. When the carriage is restored a fixed cam. forces the nought pins into operative position. The carriage rack 32 is pivoted to the carriage and held against the ratchet wheel 14 by a spring. When the carriage is restored the rack teeth slide backwards over the ratchet wheel teeth. Key construction. The 0 key 9, Fig. 16, has a projection on the same level as the 00 and 000 keys so that any two or all three of these keys can be depressed simultaneously by one finger.