Patent GB-954817-A (GB)
Abstract: 954,817. Calculating apparatus; division. WALTHER BUROMASCHINEN G.m.b.H. Nov. 23, 1961, No. 41877/61. Heading G4B. In a ten-key machine, the selection of the decimal point position for a division operation selects a decimal point type 27 from a set interspersed among the type bars and prepares right shift of the totalizer 29. The dividend is keyed on to a pin carriage 17 and the decimal point set by means of a slider 16 integral with a plate 59. The dividend key 14 is depressed: the totalizer 29 is shifted right by screw 30 until the end 63 of a stop bar 64 contacts a step 62 on plate 59; rearward movement of the machine bar 21 follows to release the differential actuators 19 to their springs, entering the dividend on to type wheels and into a socalled computing unit 24 (known cam wheels or driving pawls); on restoration of bar 21, the dividend is printed and is transferred from unit 24 into the totalizer 29, and the unit 24 is zeroized. The divisor is keyed, the divisor key depressed and the divisor is entered into unit 24 whereupon division by repeated subtraction and shift takes place in known manner. The machine has auxiliary totalizers 25, 26 which are not relevant to the present invention. Actuation of the dividend key is not possible unless the totalizer 29 is in home position. Selecting decimal point type. Lateral movement of plate 59 (Fig. 2) is transmitted as longitudinal movement of rod 52 (Fig. 4) which rocks lever 48 and rotates cylinder 42 in the surface of which are a number of blind holes 44 located along a helix. The result is that only one hole 44 is opposite a projection 41 on each of the type holders 35. When bar 38 is lowered only one type holder can move rearwardly sufficiently far to reach the platen 40. Drive clutches (Fig. 10). The sequence of operations is achieved by control of a totalizer shift clutch 65, a machine bar clutch 66, and a computer unit clutch 67. In clutch 65 the driven shaft 68<SP>1</SP> is connected to drive shaft 68 by a selected one of a pair of pawls 72 (one shown) for clockwise or anticlockwise rotation. The shaft 68<SP>1</SP> rotates screw 30 (Fig. 2). A pawl 72 is released to its spring to make a driving connection between the shafts by releasing a lever e.g. 75 which is held latched against spring 77 by locking lever 81. At the end of one revolution lever 75 is cammed back by plate 88 bearing on roller 87 to disengage pawl 72. As shown actuation of lever 74 results in right shift of the totalizer, of lever 75, left shift. Clutch 63, controlling the movement of machine bar 21, connects driving shaft 69 and driven shaft 69', is associated with levers 91, 92 of which the latter permits rearward movement of the bar 21 and the former its restoration to home position. Clutch 67, controlling rotation of computor unit 24, has a single control lever 99. The roller 104 cooperating with cam 103 to relatch lever 99 is carried on a separate lever 106 which acts on pin 108 on lever 99. Totalizer shift control. Depression of dividend key 14 (Fig. 3) raises a rod 113 which supports a lever 115, the end of which rocks locking lever 80 thereby engaging clutch 65 to right shift the totalizer. On each rotation of the driven shaft 68' of clutch 65 a lever 136 is rocked which actuates a pawl 125 through levers 133 and 129. Depression of key 14 has lowered the pawl 125 into engagement with ratchet 124 on stop bar 64 through levers 149, 151 and 155. On each right shift of the totalizer the stop bar is moved one step forward of the machine until it contacts a step 62 of plate 59 (Fig. 2). One more right shift is made during which, since bar 64 cannot move, lever 133 is rocked anticlockwise. This, through lever 158 and link 160, rocks clutch 65 locking lever 81 to initiate totalizer left shift. Lever 163 (Fig. 10) which moves with lever 81 relatches the locking lever 80. Left shift of the totalizer carries with it a frame 170, 172 (Fig. 2) which supports the rod 113. The movement of the frame only follows depression of the dividend key since raising of rod 113 brings a pawl 177 on the totalizer into engagement with a ratchet 169 on the frame. The side 172 of the frame through levers (Figs. 7 and 8, not shown) resets lever 75 (Fig. 10) and stops left shift after one revolution of clutch 65. Simultaneously clutch 66 is engaged by raising link 200 (Fig. 10) to unlatch lever 92. The machine bar 21 makes its rearward sweep at the end of which by means of a pin 204 on plate 203 on the driven clutch shaft 69<SP>1</SP> through a linkage (Fig. 9, not shown) the computor unit clutch 67 is engaged and the dividend transferred to the totalizer. Actuation of the dividend key has caused a pawl 223 to engage a pin 222 on cam follower 106. When follower 106 moves to the right at the conclusion of the single rotation of the computor unit clutch, lever 93 is operated to engage clutch 66 for the forward and homeward sweep of machine bar 21. Means are provided to prevent the rocking of the cradle 170, 172, and thus the depression of the dividend key, unless the totalizer is in home position.