Patent GB-971662-A (GB)
Abstract: 971,662. Calculating machines. ADDMASTER CORPORATION. Aug. 8, 1962 [Aug. 8, 1961], No. 30381/62. Heading G4B. Errors arising when totalling or sub-totalling crawl carry totalizers are obviated by adjusting the positions of stop levers 113 so that zero stops 111 on the register wheels cannot be engaged by the levers when wheels although registering 9 are nearly at the zero position due to partial carry. A register wheel 76 (Fig. 16) comprises at two opposite parts of the circumference three sections 110L, 110I and 110H. If the order of the totalizer to which the register wheel belongs is set at a value in the range 0. 25 to 5. 9 then, at the beginning of a total or subtotal operation, section 110L will be opposite lug 112 on associated lever 113, in the range 6 to 9. 75 section 110H is opposite lug 112, and in the range 9. 75 to 0. 25 section 110I is opposite lug 112. On each lever 113 is a pair of ears 115,116 lying in different parallel planes so that the ear 115 of one lever 113 moves in a plane closely adjacent the rearward ear 116 of the next higher order lever 113 (Fig. 24). During a total or subtotal cycle a rod 131 freely carrying a number of wedges 130 are lowered so that each wedge senses the relative positions of two adjacent levers 113. If, as shown in Fig. 24, the lug 112 on one lever is contacting portion 110H of a register wheel and the lug 112 on the next higher order lever is contacting portion 1101 of the next register wheel the wedge 130 locates itself against ear 115 on the lower order lever and cams the higher order lever through ear 116 so that its lug is clear of the zero stop 111 (the edge between 110H and 1101). The situation of Fig. 24 arises when the two lower orders register at least approximately 75 and the higher order is registering the digit 9 which with the partial carries set it to represent at least 9.75. Keyboard, pincarriage. Depression of a key 11 (Fig. 2) sets a pin 12 in an arcuate pin carriage through a flexible cable 28. The key also rocks a bail 44 which through an ear 43 depresses an escapement pin 40 so that the carriage is stepped one order. The pins are frictionally held in set position and are returned by a cam surface (not shown) when the carriage is returned. Depression of the "9" key sets only the escapement pin. Differential actuators comprise print wheels 14 carrying types 15, toothed portions for engagement with the totalizer 18 and abutments 41 engaging the set pins. Rotation of a wheel 14 is limited by a pin 213 which engages the corresponding tooth of a stop comb 212. The wheels are turned by a cam operated universal bar 54 suspended on a yoke pivoting on the shaft 31. Each wheel has a slot 62 in which is located a flexible tail 64. A recess 69 in the tail normally engages the universal bar 54 but when a wheel 14 is arrested by a set pin the bar slides over the tail 64 which yields. The frictional engagement between the bar and tail is sufficient for return of a wheel. The print wheels are aligned when the machine is not in use and during the printing part of a machine cycle by a bail 156. The home position of a wheel is one quarter of a tooth pitch anti-clockwise of zero registration to permit easy setting of the zero pins. Function selection. The rocking of accumulator shaft 74 relative to the differential actuators is controlled by a cam follower 91 (Fig. 6) slidable and rockable on a shaft 114 and engageable with any of three cam tracks on a cam wheel 86 on the main shaft 21. The selection of the cam track is determined by lever 99 (Fig. 12) which when rocked slides cam follower 91 along the shaft 114. If no amount has been entered in the pin carriage a stud 102 on the carriage retains a plate 104 in the position shown. If an add control key is depressed lever 99 is released to spring 101 but is held in central position by lug 107 on plate 104. The accumulator is meshed with the actuators on their advance and retraction and a subtotal takes place. If an amount has been entered stud 102 moves to the left in slot 103 and plate 104 is moved so that lug 107 is opposite a cut-out in lever 99. When the add control key is depressed lever 99 rocks to move cam follower to engage the left-hand cam track which is so formed as to mesh the accumulator with the actuators only on their retractionan additive entry. Pressing the subtract key causes a total or subtract operation dependent on whether an amount has been entered. Lever 99 is rocked to the right to cause the follower to engage the right-hand cam track. When the pin carriage is in home position a ledge 127 on plate 104 (Fig. 12) is so positioned as to allow free movement of levers 113. If a number has been entered, however, the rearward movement of plate 104 causes the ledge to engage lugs 125 on the levers 113 and prevent their movement. The accumulator is aligned by lugs 128 when out of mesh with the differential actuators. In a total or subtotal operation the levers 113, in frame 117 are first rocked so that lugs 112 can sense the portions 110L of the register wheels. The frame is then rocked so that the lugs transfer to the portions 110L and engage the zero stops 111, if appropriate.