US2398286A - Calculating machine - Google Patents

Description

April 9, 1946.

B. CARLSTROM ET AL CALCULATING MACHINE Filed June 3 1941 10 Sheets-Sheet 1 April 1946- B. cARLsTROM ET AL.-

CALCULAT ING MACHINE Filed June :5 1941 '10 Sheets-Sheet 2 p 9, 1946 B. CARLSTRC'JM EI'AL 2,398,286

CALCULATING MACHINE 'Filed June a, 1941 10 Sheets-Sheet 3 Apfil 9, 1946. B. CARLSTROM' ETAL CALCULATING MACHINE 10 Sheets-Sheet 4 Filed June 3, 1941 April 9, 1946. B. c'ARLsTRoM ETAL CALCULATING MACHINE l0 Sheets-Sheet 5 wNM Filed June 3 1941 1 mama \lu mm a NN NNN April 9, 1946- B. cARLsTR6 EI'AL CALCULATING MACHINE Filed June 5, 1941 10 Sheets-Sheet 6 QN QM Nmw W N JLLW April 9, 1946.

B. CARLSTRCM ETAL CALCULATING MACHINE Filed June 3 1941 w 10 Sheets-Sheet 7 Aprll 9, 1946. B. CARLSTROM ETAL 1 2,398,236

. CALCULATING MACHINE Filed June 5, 1941 10 Shgts-Shet a FIG. 16.

F/G. l/c.

B. CARLSTROM ET AL CALCULATING MACHINE April 9, 1946.

Filed June 3 1941 10 Sheets-Sheet 9 am um April9, 1946. B. CARLSTROM ETAL 2,398,286

- CALCULATING MACHINE Filed June a, 1941 10 Sheets-Sheet 1o awn/mks 3 4 5 Patented Apr. 9, 1946 CALCULATING MACHINE Bengt Carlstriim, Erik Grip, and Store Tooreli, Atvidaberg. 'Sweden, minors to Aktiebolaget Facit, Atvidaberg, Sweden, a corporation of Sweden Application June 3, 1941, Serial No. 396,474 7 In Germany June 15, 1940 a 20 Claims.

This invention refers to power-operated calculating machines. Automatic calculating machines have been constructed, but they are rather complicated and bulky. Especially for pin wheel machines having an actuator (rotor or drum) rotable in two directions, it heretofore has not been possible to construct a simple and reliable mechanism for automatic shifting both to the right and to the left for multiplication and division.

' or division key has been released.

Another purpose of this invention is to create a reliable mechanism for this purpose, which is controlled by a control lever which may be set in three positions.

Another purpose of invention is to provide a calculating machine with acontrol lever settable in three positions. by means of which the machine is set for full-automatic division and also for multiplication with shifting of the actuator to the right or to the left.

@ther purposes will he evident from the following specification.

Embodiments of the invention are illustrated in the annexed drawings, by way of example.

1 shows a plan view of the principal parts or the machine. Only those parts are shown which are necessary for explaining this invention {chiefly the shifting means, the keyboard and the actuating means for plus and minus revolutions controlled thereby).

Fig. 2 is an end view from the right in Fig. 1 and illustrates a part of the control for the driving mechanism.

Figs. 2a and 2b show details taken from Fig. 2.

Fig. 3 shows an end view from the left in Fig. 1 and also discloses the members for reversing the revolutions counter actuator.

Fig. 4 shows the parts illustrated in Fig. 3 as viewed in the direction of the arrows IVIV of Fig. 3. (Thus, Fig. 4 is a partial rear view.)

Fig. 5 shows the revolutions counter actuator,

with its controlling means.

Fig. 6 shows a detail seen in the direction 01 the arrows VI-VI of Fig. 2.

Fig. '7 shows a detail viewed in the direction of the arrows VIIVII in Fig. 2.

Fig. 8 is a partial rear view, that is, in the direction of the arrows VIII-VIII in Fig. 1.

. Fig. 9 shows the right hand part of Fig. 1, some parts being broken away to show the parts below.

Fig. 10 is a view looking in the direction of the arrows X-X in Fig. 1.

Fig. 11 is a front view of the control keys and the adjacent parts.

Fig. 1141 shows a front view of the addition or key and the multiplication or X key and the adjacent parts.

Fig. 112: shows a front view of the subtraction or key and the division or key and the adjacent parts.

Fig. lie is a detailed view of an arrangement for preventing simultaneous depression of the multiplication and division keys.

Fig. 12 is a view of the driving coupling seen the direction of the arrows EI-XI of Fig. 16.

Fig. 13 is a view of the machine seen from below.

Fig. 14 shows a front view of a detail of the shifting mechanism.

Fig. 15 is a cross-sectional view taken on the line XV-XV in Fig. 14.

16 shows a modified embodiment in which n addition key only but no subtraction key is resided. Direct subtraction is then eifected by pressing the key, when the operating lever set to its lowermost position.

is plan view of a gear train for driving the actuator and other parts of the apparatus.

Fig. 18 is an end view of the gear train shown Fig, 1'7.

Fig. 19 shows a detail of the mechanism for preventing shifting in adding and subtracting operations.

Fig. 20 shows a detailed view of the upper part of Fi 6. i

Fig. 21 is a view looking in the same direction -as Fig. 10, and illustrates how the machine is board of the machine.

The machine as shown is in its principal features constructed in accordance with U. S. Fatouts Nos. 2,108,596 and 2,243,075, though the invention is not limited to that type of machines. The driving mechanism may be constructed in accordance with U. S. Patents Nos. 2,068,899 and 2,127,102. The accumulator and the revolutions counter (or quotient register) may be cleared in well-known manner, for instance by hand (see U. 5. Patent No. 2,.l8ilfl i8), while the setting mechanism or actuator may be cleared in accordance with U. 5. Patents Nos. 2,068,899 and 1,927,771.

The calculating machine shown the draw inss'is oi the ii-d mer 0 pin v/heel type and a setting" inech Wheel. rotor) or noteator t, which is rotatalely iournalled in a carriage M movable along the shaft which is the principal driving 1 e effecting"; the cal culatins; operations, this sh ii with the actuator l rotated in either direction (minus revolutiou clocluvlse and plus revolution counter-=- clochviise is ig. by means of an electric mo tor in .lFor setting the amounts i t lte'i are provid i .he corresnonc no, llllllichers. in ad the mech 1e hes three t Etheys ill" till). The hey he ectuetor by step to the U3" tilt) is for flitt ng the same e left. The 7 l i is ior to 1 ion, is for ts l .h ting the iactors division. When this keytilt) is depressed, the actuator." G moves lirectiy to its extreme f hand posit" .The "lune has nos latine' and sh t hoote s. plate and c he positions, namely, the two post one of inult piication ti and h' and the ncsition of division c. these positions the lever lti is latched a latching arm lltl") cooperating with three notches in the end oi lever iii 1. Said latch ing' arm is biased by a tension spring 21M and rockable on. the pin ill secured. to the bottom plate Zllil. An arm tit oi the control lever till is movabl in a cam slot ti l (this. 3) of a lever 215, which. rochahie on the pill 218 secured to the left hand side well ill of the machine frame.

A revolutions counter actuator (or quotient tooth) its is dlsplacealely splined on a shaft zit (Figs. 1, 3 and 5) and actuates the revolutions counter N. This shaft is rotatably Journalled in the side walls oi. the machine frame and is also movable axially, and it carries the gear 220 (Fig. 5) rigidly secured thereto. The hub of this gear carries on either side coupling projections 22L When the shaft 2! is moved axially, one or the other of these projections engages a slot in the hub of one or the other of two gears 222 or 223,

aseaceo respectively, depending upon the direction oi motion. These gears are loosely rotatable on the shaft Zl-il and. are permanently driven in opposite directions from the main shaft 5 by gear :5 transmissions. The gear 220 drives the tens transfer rotor of the revolutions counter.

When the shaft H8 is moved axially in the direction of the arrow marked in Fig. 5, the shaftis driven by the wheel 222 which rotates in the same direction as the shaft t, that is as the actuator 4. Thus the shafts ii and rotate in the same direction and consequently the coin ELLOP. t and the revolutions counter actuator flit have the same directic of rotation. For multiplication this is th normal position. of the shaft l l") and is herein called its plus position.

if the shaft tilt is moved daily in the all-- i'ection oi the arrow to its extreme left posi-- tion, the shafts i5 and till co ed to rotate in opposite directions, and hence actuator t and the revolutions counter actuator Flil rotate in opposite directions. This is the not; tioh for division and is called its in the axial suction of the shaft $11?) is eii'ected by (Figs. 3 and 5) which is roclouhle ill he lever lit.) on the stationary Ellil and '5' This cam coopert' with an peripheral slot ilfl'i' at e d When the lever iii Elli ro i tion. (see arrows), the Elf? is me ii us position, and vi tio the .l' E 0 r u the control is purpose the nob or used which is through. slot in machine casing it can be actuated by hand from the outside.

If this knob is pressed downwards and then moved in the direction of the arrow, the shaft tilt is moved irom its position to its position, though the control lever Wt is still in its to position '1) for multiplication. Now, it is nossible to effect minus multiplication (negative multiplication) in the machine. Euch minus multiplication is, ior instance, used for solving problems of the form: ax b-c cl. First, the first product uXh is calculated in the accumulator in the ordinary Way by positive multiplication (plus multiplication) and then the difference is di rectly calculated by calculating the second product c cZ by use of revolutions, that is as minus multiplication. To attain a correct "indication of the multiplier in the revolutions counter in such operation, it is necessary that the shaft 218 is moved to its minus position, so that during the minus multiplication the actuator 4 rotates in the 75 negative direction revolutions) but the revoout of the path of the member 231.

lutions counter actuator 2 I3 in the positive direction revolutions).

If the control 1c /er 20I is in its "c" position (for division), the knob 234 may be moved by hand in the direction of the arrow in Fig. 3, for carrying out minus-division or negative division, that is, division with rotation of actuator 4 and tooth 2I9 in the same sense. Such operation can, for instance, be used for solving a problem of the type a+bc+d. Then the first quotient a-z-b is calculated in the ordinary manner (actuator 4 rotating in one direction and revolutions counter actuator 2 IS in the opposite direc-, tion, this may be termed divisionf' or positive division), and the quotient is left in the revolutions counter N (which is not cleared) The shaft 2I8 is moved to its position (position of like rotation) by manipulation of the knob 234 and the second quotient c:-d is calculated; during this operationthe actuator 4 .and the tooth 2 I9 both rotate in the same direction so that the second quotient c-z-d thus calculated is directly subtracted from the first quotient a+b. The difference directly appears in the revolutions counter N. 7

As is shown in Fig. 3, the innermost edges 23I I of the two outermost notches 23l slant towards the "central notch. If the lever 225 has been moved out of its normal position by means of the knob 234, when the control lever 20I is in either of its' positions a," b and c, and then the lever 20I is moved from its b-position to its c"-position, or vice versa (or from its a-position via its b-position to its c"-position, or vice versa), the pin 233 slides on the slanting edge 23 and enters the central notch 23I. Thus, as soon as the lever 20I is shifted from its b"-position to its c-position, or vice versa, the arm 229 always will have its central notch 23I in engagement with the pin 233.

At its top the arm 2I5 has a portion 236 extending at right angles to the arm (Figs. 3 and 4) on which the member 23"- is rotatably journalled on the pin 230. The free end of the member 231 is pressed-downwards by a tension spring 239 to engage the'tens transfer lever I of the highest denomination of the accumulator. The lever I00 tain cases, is secured to the slide 2 in such manner that the lever 202 is both rockable and slidable in relation to said slide. The disconnecting lever 202 has a recess 244 with two notches through which one of the pins 243 passes. A tension spring 245 connects the slide 24I with the lever 202 and forces the latter to assume either of the two positions determined by the two notches of the recess 244, and shown in full-lines and dotted lines, respectively, in Figs. 1 and 13. A stud 246 is secured to the bottoin plate 205 and pivotally supports a lever 241. This lever carries a pin 248 on which a hook lever 243 is rockably journalled. This pin also enters a slot inthe step shifting plate (left-right-shiftin'g plate) 250, which carries two pins 25I, 252 and is drawn by a tension spring 253' tothe right by. a right-hand arrow as shown in full lines is rocked upwards, when the capacity of the accumulatoris exceeded, and thus an over-draft occurs in over-addition or in over-subtraction, that is when larger value than that already registered is subtracted therefrom. If the lever I00 is thus rocked, when the lever 20I is in its position a or b, the lever I00 only rocks the member 231 upwards in an idle stroke, as shown in Fig. 3, because the stop impulse lever I02 is v But if the lever 20I is in its c-position, the stop impulse lever I02 is in the path of motion of the member 231, when rocked upwards by, the tens transfer lever I00 as just described so that said member rocks the lever I02 upwards or counter-clockwise and stop the actuator, as described below under the heading: Ordinary division with unlike rotation of actuator and revolutions counter actuator.

Right, left and non-shift tabulation control shifted the slide 24I follows it. By means of the pins 243 the disconnecting lever 202 which serves for disabling the tabulation to the rightln cerin Fig. 1, then the shifting plate 250 is in engagement with the lower end of a step shifting lever 254 (Figs. 1, 13, 14, 15) for shifting to the right. But if the control lever 20I is moved into its position a, the slide 24I with its arm 24 is moved to the left in Fig. 1 and strikes the. pin 252 to pivot the shifting plate 250 to the left so that this plate now engages the lower' end of a step shifting lever 255 (Figs. 1, 13, 14 and 15) for shifting to the left. When the lever 20I isv switched over to its position 0, the shifting plate 250 is drawn by the tension of the spring 253 to engage the right step shifting lever 254 and remain in contact with it. But if the disconnecting lever 202 is in its extreme left position in Fig. 1 (operative position) indicated by a vertical arrow (1) in Fig- 1, while the lever 20I is in its position b, the shifting plate 250 with its pin 25I engages the edge 202I of the disconnectinglever 202 and thus is kept in its central inoperative position, not engaging either of the levers 254 or 255. If now the lever 20I is moved to its position a," the shifting plate 250 is rocked to engage the step shifting lever 255, and when the lever 20I is moved into its position c," the shifting plate 250 again engages the step shifting lever 254. Thus, it is evident that when the disconnecting lever assumes its said operative position, the automatic step by step shifting is inoperative only in the position b of the lever "201. In other words, the disconnecting lever 202 is alway ineffective when the lever 20I is in its position a" or c.

When the step shifting lever 254 is actuated, the actuator 4 is automatically shifted one step to the right; and if the step shifting lever 255 is actuated, said actuator is shifted one step to the left. As is shown in Figs. l-iand 15, the lever 254' journalled on the shaft 35 of the keys acts directlyon the step shifting pawl I50, I54 (see Figs. 30 and 33 of U. S. Patent No. 2,108,596), 50 that said pawl moves the rack 5| to the right. Said rack is secured to the carriage of the actuator 4 i and consequently said actuator is shifted one step to. the right. When depressed the key I91 for step by step shifting to the right acts'directly on the pawl I50, I54. The step shifting lever 255 higher denominations. The step by step shifting mechanism proper is described in detail in U. 8. Patents Nos. 2,108,596 and 2,243,075.

Disubling'the automatic shifting in end positions As described in detail below, the pivoted lever 241 performs one rocking motion in the direction of the arrow B, Figs. 1 and 13, and back again. when the actuator 4 is stopped by the catching pawls 54 and catching arms 51 (Fig. 2) after one or more revolutions for a calculating operation. This rocking motion may be transferred by the hook lever 243 to a projection 251 of the shifting plate 250. The hooir lever 249 rockable on the journal 2 18 has a recess or cam slot 256 and the cam edge thereof is engaged by a projection 290 (Figs. 1 and 8) of iJ-shaped member 259 which is displaceahle along the stationary studs 282. A compression spring Ziii presses the member 259 to the left in Figs. 1, ii and it to engage the momher 263 which serves to couple the revolutions counter actuator iii to the carriage of the actuator 4 during the calculating operations sec U, S. Patent No. 2,2d3,075). When the member 283 is in its position of rest (extreme right position) and the levers 2M, 202 are in their position shown in full lines in Fig. l, the member 2% by means of its projection 28d keeps the hook iever 249 in such position that the projection 281 is out of the path of motion of the lever 249 so that the swinging lever 241 does not drive the shifting plate 250, the pin 2 48 sliding in the slot of the shifting plate 250. But if the actuator 4 is tabulated or shifted to the left, for instance, by means of the key I99, the member 259 follows due to the pushing action of the spring 281, until said membr is checked by a stop. In the drawings this stop is the left hand side wall 2". This motion of the member 259 from its full line position to its position shown in dash-and-dot-lines is equal to or shorter than the axial distance between two adjacent. totalizer wheels. This motion of the member 259 causes the projection 249 to rock the hook lever 249 into engagement with the projection 251 so that at the next swinging motion of the lever 241 the shifting plate 250 follows and aotuates whichever cf the step shifting levers 254 or 255, that said plate is set to engage.

When the actuator 4 is shifted to the right and the member 263 (and the revolutions counter actuator 2I9) coupled thereto moves from the next to the lowest wheel (denomination) of the revolutions counter to the lowest wheel or denomination thereof, that is to its extreme right position, said member 253 strikes the member 259 and moves it to the right in Fig. 1, from the position iii shown in dash-and-dot-lines back to its full line position. Upon the automatic shifting of the actuator, this motion takes place simultaneously with the motion of the hook lever 249, and consequently the cam slot 259 is necessary to permit the relative motion of the projection 24. in relation t0 the hook lever 249. When the lever 241 is swung back again (in the direction opposite to the arrow B), the hook lever 249 is pivoted by the cam slot 258, out of engagement with the projection 251 and consequently the actuator 4 cannot be shifted further to the right,

The angle of rotation of the hook lever 242 is substantially equal to the angle 01 rotation of the shifting plate 250, when the latter is moved from its right position to its central position (Fig. 1), and consequently the hook lever 24! is always in engagement with projection 251 of the shifting plate 250, when the lever 24! la in escapee again, this has consequently no influence upon the actuator.

Setting to plus and minus revolutions A small pawl 265 (Figs. 1, 2 and 13) is journailed on the pin 264 secured to the swinging lever 241. A tension spring 265 tends to draw said pawl; into the path of a driving lever 251, swinging to and fro but normally the bent part 2% (Figs. i and 2) of said pawl is locked by the bent portion 289 o a lever 21! fulcrumed on the right side wall 21!! of the machine frame. The lever 124i also has a bent portion 212 to which the pinilit is riveted.

it plus minus driving lever 214 (Figs. 1, 2 and 13) is also rotatably journalled on the shaft 248. A. pawl tilt (Figs. 1, 2, 9 and i3) is pivoted on lever 214 by means of a pin 215. A tension spring in (Fig. 9) tends to draw said pawl into the path of the swinging driving lever 2151, but the pawl is normally locked and kept out of the path of said lever by means of its'hent projection 21% which engages one edge of the lever 241.

The driving lever 261 actuating the pawls 255 and 215 is rockable on the journal 219 (Fig. 2) and has an oblong slot in which the eccentric 281 runs to rock the lever to and from fro. The shaft 250 of the eccentric is driven through gear transmission (not shown) by the motor of the calculating machine and rotates as long as the motor runs.

The slide 2" carries a pin 292 (Figs. 1, 9 and 13) which enters a slot in the front end of a lever 282 which is pivoted on the stud 294 secured to the bottom plate 206. The back end of said lever is hook-shaped and locks the pawl 215 against the action of its spring 211, when the lever 20! controlling the slide 2" is in its position "a" or "b. The plus-minus-driving lever 214 also carries a pin 295 (Fig. 9) which enters a slot 245 in the end of a plus-minus-control plate 281, Figs. 1, 2, 9 and 13. Between the driving lever 214 and the control plate 281 a tension spring 248 is arranged which moves the plate 291 in the direction of the arrow F (Fig. 1), whenthe lever 214 is rocked backwards. that is counter-clocl-:- wise in Fig. 1. Said control plate has shoulders or projections 298 which are moved into engagement with either of the arms 290, 291, accordingly as the control plate is rocked to the left or to the right. respectively, in Figs. 1 and 9. The arms 290 and 29l are integral with the keys I and 2, respectively. The shifting of the control plate 241 from the right to the left (that is, from minus to plus) and vice versa, is effected by the pin 292 fixed to the plate 281 which engages a slot in the bent portion 292 of the minus plus reversal lever 294 (Figs. 1, 2, 6 and 13). The reversal or shifting of this lever 294 is described in detail below. A common tension spring 295 keeps the two levers 241. 214 in their positions of rest. because the spring presses said levers against studs 296 and 291, respectively, which are secured to the bottom plate 294.

On the studs 294 and 299 secured to said bot- I tom plate the minus locking member 299 (Figs.

1, 8, 9 and 13) is displaceable and said member has a slot 333 through which the projection 233- of the member 233 passes. A spring "I is tensioned between the member 253 and the locking member 233, which at its right end carries two abutments or projections 332 and 303 forming stops (Fig. 9). Inthe position of the minus looking member 233 shown in the drawings its projection 332 locks the pawls 213, while its projection 333 engages the bent portion 233 of the reversal lever 234. When the actuator 4 and coupling member 233 of the revolutions counter actuator 2l3 are shifted or tabulated to the left. that is, towards higher denominations. moving the member 253 into its position shown in dash-and-dotlines, as described above, also the minus locking member 233 is moved to the left.because the left edge of the projection 233 strikes the leftend in Fig. 2) and is stopped in such position that the slide 3, in its motion in the direction of the arrow C. does not act on the locking-down pawls 304 and 305.

When the actuator 4 is in its position of rest, it is held in well-known manner by the catching arms 51, the pawls 34 and the spring 53, see U. S. Patent No. 2,127,102. The left catching arm 51 has a pin 32! which may act on the shifting impulse lever 322 rockable on the shaft 5. A projec-- tion 323 (Fig. 2) bent oil from the impulse lever 322 releases the pawl334 or 305 from the key I or 2, respectively, when the impulse lever 322 is rocked in thedirection oi the arrow D. (The lever 322 isthus rocked due to the fact that when the actuator 4'is stopped by the catching pawl 54,

this causes the left arm 51 to rock somewhat due of the slot 333. The displacement thus given to the minus locking member 233 is somewhat greatthe pawl 213 is disengaged from the projection 302 (Fig. 9). This means that said Dow] is locked by the projection 332 only when the member 233 is in its extreme right position and consequently keeps the member 253 and arm 233 in their extreme right -p0sitions, and when simultaneously the reversal lever 234 is in its plus position shown in full lines in the drawings, that is, when the control plate 231 has been rocked in position to engage the arm 23! of the key 2. When the member 263 is in any other position, the pawl 213 is free from the projection 302.

On the right side wall 210 of the machine (Figs.

2 and 10) the power-operated driving mechanism of the machine is arranged, as shown in U. S. Patents Nos. 2,068,899 and 2,127,102. This mechanism is controlled by the arms 230 and 23! of the keys I and 2 respectively. When one of these keys is depressed, the locking- down member 304 or 305, respectively, belonging thereto enters a corresponding notch of the key and looks it in its depressed position. These locking pawls 304 and 305 are rockable on the pin 303 and each of them is actuated by its individual tension spring 301. To the shaft 5 of the rotor 4 a cam disc 303 is secured on which the roller 303 of a releasing arm 3i 0 runs. This arm is rockably joumalled on the key shaft 35 and carries at its lower end the small slide 31 I, a pin 312 secured to the arm 3l0 passing through the slot 3| 3 of said slide. In addition, this slide has a slot 3 through which passes the pin 3l5 which is secured to the side wall 210. and said slide also has a bent portion 316 which strikes the pin 3l1 of the locking-down pawl 304 or 305 and releases said pawl, when the slide 3 is moved in the direction of the arrow C. Then the key I or 2 is again restored to its position of rest by means of its usual spring. The slide 3 also has a projection 313 (Figs. 2 and 7) which slides in the curved slot 3l3 of the .bent portion 320 of the slide 24!. Figs. 2 and '7 jection 313 is lifted by the cam slot 3| 3. Then the slide 3 is rocked on the pin 315 and at its slot 3| 3 slides on the pin 312. The bent portion 3| 5 of the slide 311 is thus lowered (clockwise to the shock.) A tension spring 324 presses the impulse lever 322 against the pin 32 i On the right side wall 210 the hooks 211 and 326 are journalled'on the pin 325 (Figs. 2, 2a and 2b). The hook 21l is drawn upwards by a tension spring 321 and rests with its striking point 323 against a pin 323 on the impulse lever 322. As described above, the hook 21l has a bent portion 233 which engages the projection 253 on the/pawl 235 to lock the latter, and it also includesv a cam .330 to be engaged by the pin 213 of the swing lever 241. The hook 323 rests with its lower edge against the part 233 of the hook 211 and actuates the pin 332 on the contact lever 331 when the last-mentioned hook is swung in the direction of the arrow E, so that said contact lever is rocked on its stationary shaft 333 and closes the electric contact 334 for the motor, driving the machine.

On a bracket 335 (Figs. 2 and 6) secured to the external right sheet metal wall 333 of the machine (this wall is to the right of the right side wall of the frame 210; the two walls 210, 333 enclose the driving mechanism) the minus-plus-reversal lever 234 is rotatably journalled on the pin 331. As described above, at its lower end this lever has a bent portion 233 (Figs. 1 and 2) having a slot in which the pin 232 of the control plate 231 slides. At its top end the lever 234 is shaped as a fork 333 (Figs. 2, 6 and 10) to embrace one of the two pins 33. This pin 33 is extended forwards and may (as is explained in detail for the pin 33 in U. S. Patent No. 2,127,102) assume three different positions, which in the drawings (Fig. 6) are indicated by 0, and When neither of the keys i, 2 is depressed, this pin 33 is disengaged from the oscillating arm 29. If, however, the multiplication key I is depressed, the arm 23 moves the pin 33 laterally into its position when the actuating slide 30 (Fig. 20) on the oscillating arm 23 engages the slide 31 raised due to the depression of the key I. The recess which is made in the lower edge of the slide 30 to engage that of the slides 36or 31 which has been raised, is so dimensioned that when the slide 31 has been raised and pushed laterally to its extreme left position position of pin 33), as shown in Fig. 20, its left edge is not actuated by the left edge of the recess 30a, when the slide 30 is in its extreme right position. In Fig. 20 the extreme lateral positions of the slide are shown in full lines and dotted lines, respectively.

When thus the pin as has been moved to its returns to its position (zero position). that is when the machine is stopped, the latching mechanism 339 and 340 keeps the reversal lever 234 in its plus position. But when the division key 2 is depresed, the pin 33 with the reversal lever 294 is in similar manner moved to its minus position and the lever 294 is latched there by the latching members 339, 340. Now, the reversal lever 294 is in its minus position as shown in dotted lines in Fig. 1, and keeps the control plate 231 pressed to the left in Fig. 1. It now said plate 231 is displaced in the direction of the arrow F, it also moves the multiplication key i so that said key is pulled down automatically into its depressed position. But ii the pin 33 is moved into its position (Fig. 6) by manual depression of the multiplication key i, then it rocks the reversal lever 294 into its position (shown in full lines in Fig. 1) and when now the control plate 231 is moved in the direction of the arrow F, the division key 2 is pulled down automatically. To summarize: if the pin 38 is moved to its position, the division key 2 is automatically pulled down but the multiplication key I is pulled down automatically when the pin 38 is moved to its position.

The latching mechanism 339 and 340 must be so strong that its latching action is not overcome by the pressure of the spring 30! acting through the minus locking member 299 (Fig. 1).

Addition and subtraction keys The plus or addition key 203 and the minus or subtraction key 204 are rotatably journalled on the shaft 3 (Figs. and 11). By means of its tooth 342 the addition key 203 actuates a lever 344, while by means of its tooth 343 the subtraction key 204 acts on a lever 345. The levers 344 and 345 rock on a stationary pin 343 and are pulled upwards by tension springs 341 I and 348, respectively. On these levers hooks 349 and 350, respectively, are rockably journalled. A pin 35! secured to the bottom plate 208 passes through slots in said hooks so that at the motion of the levers 344 and 345 the hooks are rocked on their pins 352 and 353, respectively (see Figs. 11a and 11b). The levers 344 and 345 have elongated slots through which the pin 35l passes to permit rocking of the lever. A projection 354- of the lever 344 acts on the multiplication key I; and the lever 345 has a projection 355 which acts on the division key 2. Also the lever 344 has a part 353 which actuates the hook 353 (Figs. 10, 11, 11a, 11b); and in similar manner the lever 345 has a part 351 which actuates the hook 353. The keys I and 2 are kept in their depressed position by the locking-down pawls 304, 305 which are releasable by the slide 3 of the release arm 3l0 (Fig. 2) Or by the impulse lever 322, according to the position of the control lever The keys I-2 carry the small pawls 360 and 33!, respectively (Fig. 10), which are pressed by springs 332 against pins or projections on the keys.

The keys |-2 act on the slides 333-454, re-

- spectively (Fig. 10). which are rockabl and displaceably attached to the stationary bracket 335. Tension springs 333 act on said slides, which have bent projections 331-333, respectively, and on these projections hooks 333-310, respectively, are rockably journalled. Tension springs 31l-312, respectively, act on these hooks and the latter engage the slides 33 and 31, respectively (Figs. 2, 6 and 10). These slides and their mode oi operation is described in detail in U. S. Patent No. 2,127,102. They are pulled downwards by tension springs 42.

asoaaae The release arm 3l0 has a slot engaged by a pin 313 (Fig. 10). This pin is mounted on the lever 315 rcckable on the stationary pin 314 and the lever 315 also has a projection 313. When the lever 315 is rocked, the projection 313 enters the slot 311 of the hook 353. When this hook is pressed down by either of the keys 203 or 204 (Figs. 10, 11, 11a and 11b), the projection 316 (Fig. 10) engages the projection 313 of the hook 353 so that the hook 353 is pushed backwards (to the right in Fig. 10; see arrow H) when the lever 315 is rocked. On a pin 313 secured to the slide 380, the hook 353 is journalled, and a spring 33| is tensioned between the hook 353 and the slide 330. Said slide is displaceable on the stationar ins 332 and carries a pin 333 which actuates the impulse lever 322 (Figs. 2 and 10) when the slide i moved in the direc tion of the arrow H (that is backwards) so that the hooks or locking-down pawls 304 and 305 are rocked to their release position. In addition, the slide 330 carries a pin 384 (Fig. 10) which releases the two hooks 369 and 310 as the slide moves backwards.

The gear wheel 335 (Figs. 10 and 12) is permanently connected with the motor shaft by means of a transmission and consequently is rotated, when the motor runs. The hub of the wheel 335 has a slot 383 to be engaged by the flange 331 of the gear wheel 333, when the two wheels are to be coupled to each other. Said wheel 383 has a coupling cam 389 with an oblique face 390. A compression spring 39! presses the wheel 383 with its cam. 339 against a coupling arm 392, Figs. 10 and 12, which normally holds the flange 331 disconnected from the slot 383. Said arm is rockable on the stationary pin 393. The wheel 383 permanently meshes with the gear wheel 334 (Fig. 10) on the shaft 14, and on the same shaft a clearing cam is secured (see cam 11 in U. S. Patent No. 2,068,399). In its innermost or back position the slide 330 is locked by a pawl 395 having a tension spring 396. During the clearing operations this pawl is released by the pin 391 on the wheel 394 which strikes a surface or projection on the pawl.

To the coupling arm 392 (Fig. 10) onelend 0! a link 398 is articulately connected by means of the pin 399. The other end of said link is articulately connected to the arm 400 by means of the pin 40L Said arm is rockable on the stationary pin 402 and carries a projection 403 which can enter a slot 404 of the disc 405 secured to the actuator shaft 5. The arm 400 may be rocked by manipulation of a clearing key 403.

Obviously, this key can only be depressed when the actuator 4 is in its position of rest (stopping the clearing means 403; 393; 330; and 392 to their position of rest. During the whole clearing operation the electric contact 334 of the motor is kept closed by the bell c ank lever 4H fulcrumed on the shaft 333. A p 2 secured to thesllde 330 enters a slot of the lever 4;

when the slide 330 is displaced backwards, that 412 rocks said lever 4 to close the contact 334.

Positions of the control lever and of the disconnecting lever As mentioned above, the chief control lever 20! may assume three positions a, "b" and "c" (Figs. 1, 11 and 13) for which the following symbolic marks are placed on the casing:

a) X b) l X and c) The disconnecting lever 202 may be set to two positions, as shown in Fig. 1, namely: the right position and the left position 1. These levers 20!, 202 control, among other operations, the automatic shifting of the actuator. 4 in the fol-- lowing manner:

I. Lever 20! in position a and disconnecting lever 202 in its left or right position: For oper-.

ations of multiplication by means of the key I the actuator is always shifted one step to the left, each time the operator takes his finger ofi the multiplication key, after the necessary number of revolutions of the actuator 4 have been made in the denomination (of the multiplier) concerned. After this automatic shifting the operator again depresses the key I for continuing the multiplication in the next higher denomination of the multiplier, etc.

II. Lever 2" in its position b and disconnecting lever 202 in its right hand position: When the operator takes his finger oil! the multiplication key after the necessary number of revolutions of the actuator 4 in the denomination (of the multiplier) concerned, the actuator is automatically shifted one step to the right. Then the operator again depresses the key I for continuing I the multiplication in the next lower denomina tion of the multiplier, etc.

III. Lever 20l in'its position b, disconnecting lever 202 in its left position: When the operator takes his finger oi! the multiplication key, the actuator is not shifted automatically (but it may be shifted manually by meansof the keys I31,

IV. Lever 20! in its position "c" and lever-202 in its left or right position: The operator depresses the division key, then immediately releases it, and the actuator carries out automatic revolutions in the minus direction (that is clockwise in Fig. 2), followed by revolutions in the plus direction (counter-clockwise in Fig. 2) etc.: and after the correct number of revolutions in the direction concerned in one denomination of the divisor the actuator is automatically shifted one step to the right. 1

These operations are described indetail below.

When the plus key 203 or minus key 204 is depressed, no automatic shifting of the actuator is effected. The mechanism for preventing automatic shifting is shown in Fig. 19. When in an adding (or subtracting) operation the slide 300 is pressed backwards (in the direction of the arrow H), as mentioned above, it rocks the lever 4H clockwise and the projection 4Ha of said lever then engages the bent portion260 of the lever 2ll from above. This causes the lever 2 to be depressed somewhat and to be locked in its depressed position. When the actuator 4 is arrested in full-cycle position, the impulse lever 322 receives an impulseand the pin 22! releases the lever 2". But said lever is locked, as just mentioned, and no shifting is effected. Because said lever 21! is locked in a somewhat depressed position, the impulse lever 422 can swing back to its podtion of rest- After each revolution the actuator 4 is cleared automatically, thatis, the machine works as an adding machine with direct subtractilm, independent of the positions of the levers III. 202.

Mom: or Ornli'rron For the different calculations the machine is After an item has been set in the actuator by means of the amount or item keys 200, the addition key 202 is depressed, and its motion is transferred to the multiplication key i through the link 344 (Fig. 11a) so that this key is also pressed down and becomes locked by its locking-down pawl 304 (Fig, 10). The pawl 300 is below the bent portion of the pawl 304 and is rocked so that its spring is tensioned. When the link 344 is rocked downwards by the key 203, the small hook 349 pivots in a clockwise direction by virtue of its engagement with stationary pin 35! so that the vertical arm of hook 340 is below themultiplication key 1. Thus, the key 203 cannot be restored, as long as the multiplication key I remains depressed, because this key locks the link 344 by means of the hook 349. When the key 203 is depressed, it also depresses the hook 358 which then can be engaged by the projection 316. When said key is depressed, it also lifts the slide 31 and the machine begins in well-known manner (U. S. Patent No. 2,127,102) a revolution in the plus direction, that is counter-clockwise in Fig. 10 so that the amount set in the actuator is entered into the accumulator or results register.

During this revolution the release arm 3i0 is rocked by the cam disc 303 acting on the roller 30! and through the pin 313 rocks the lever 315, whose projection 216 pushes the hook 358 and the slide 300 backwardsthat is in the direction of the arrow H in Fig. 10. In its back position this slide is locked by the hook 395. When the arm'3l I is rocked it moves the slide 3| I in the direction of the arrow C to release the locking-down pawl 304 to release the key 203 which is restored to its position of rest by its spring. Even if the operator keeps this key pressed down, the pawl 304 cannot again lock the key, when the arm 3! is restored, because when the pawl 304 is released clockwise in Fig. 10, and thus prevents the pawl 304 from looking the keys I and 203. The mechanism works as described only if control lever MI is in its position a or b." But if the lever 20| is in its position c for division so that the slide 3| I is disabled, the pawl 304 is released through the impulse lever 322 which is actuated through the pin 303 on the slide 380, when the latter is moved due to. the depression of the key 203. The motion of the slide 300 also releases the hooks 369 and 310 so that the slide 31 is pulled downwards by the spring 42. This slide now stops the machine after one single rotation of the actuator. The slides 36, 31 each carry one projection I003 (Fig. 21) which releases the latches 45. 46 from the guide member 30, when the slide 36 or 31 is moved downwards by its spring 42. Consequently, the guide member 39 is restored to its central position and the machine stops, as described in detail in U, S. Patent No. 2,127,102. (See details 39, 45, 46 in rested in its full-cycle position and the arms 3|0 and 315 swing back, the hook 350 is released and is pulled upwards into its position of rest by the spring 38L When displaced backwards the slide 300 tensions the spring 400, but the coupling arm 392 is kept locked by the disc 405 through the members 403; 400 and 390 and thus cannot be moved by said spring. When the rotation of the actuator has been stopped, the projection 403 enters the slot 404 of the disc 405 and the spring 408 pulls the link 398 backwards, that is, in the direc-. tion of the arrow H of Fig. 10. This motion of the link rocks the coupling arm 392 counterclockwise to release the coupling gear 308. The spring 39l now couples this gear with the power-driven gear 385 and due to this the actuator is now cleared in well-known manner (see U. S. Patent No. 2,068,899). Shortly before the end of the clearing operation, that is when the wheel 394 has rotated almost 360, the pawl 395 is released by the pin 391 and the initiating members 300; 398; 392 for the clearing are now restored by the spring 4 I to their position of rest. Thus the lever 392 is moved into the path of the oblique surface 390 of the cam 389 and during its continued rotatlonthe gear 380 disconnects itself from the gear 385, and the clearing action is now finished.

During the whole clearing action the slide 380 keeps the motor contact 334 closed by means of the pin 2 and the levers H I and 33L Subtraction When the subtraction key 204 is depressed, after an item has been set in the actuator, an operation of subtraction is effected in a manner quite analogous to that described above under the heading Addition; the only difference is that the actuator'4 rotates in the minus direction, as a result of the slide 38 being raised by the key 204 (whereas the addition key 203 raises the slide 31).

As was mentioned above, the operations of addition and subtraction are quite independent of the setting of.the levers 20I, 202.

Multiplication For multiplication an item (multiplicand) is entered into the actuator 4 and the chief lever 20! is set to its position a or 1), while the disconnecting lever 202 may be set in its left or right position. The setting of the lever 202 determines the position of the shifting plate 250, when lever 20I is in its position b. V

If the knob 234 (Figs. 3 and 4) was not separately set by hand, the revolutions counter actuator 2 I 9 Fig. 5) is set to rotate in the same direction as the actuator 4. In other words, for multiplication the revolutions counter actuator 2I9 always rotates in the same direction as the actuator 4. even though said actuator 4 can be caused to rotate in the negative direction by depression of the key 2. Also the stop impulse lever I02 for division (Figs. 3, 4) is disabled, because it isout of' the path of the arm 231, when the latter is.

actuated by the tens transfer lever I00 of the highest denomination. The pawl 215 is locked by the arm 283 Figs. 1, 9) and the small slide 3 is in its operative position shown in Fig. 2. Either of the keys I or 2 is now depressed to initiate positive or negative operation, respectively and the actuator begins to rotate correspondingly. The slide 3 moves the locking down pawls 304 and 305 to their inoperative position so that the depressed key I or 2 is restored to its position of rest, as soon as the operator releases it. When the key is restored, the motor contact 334 is opened and the actuator 4 is stopped in well-known manner, for instance, as described in U. S. Patent No. 2,127,102; either of the catching pawls 54 then stops the actuator (see also description under the heading "Addition" above). At a minus revolution (clockwise in Fig. 2), the actuator is caught by the right catching arm 54 and 51, but bounces back against the left catching arm 54 and 51 which is rocked thereby. This causes the pin 32I to rock the shifting impulse lever 322 so that this arm receives a shifting impulse. If the actuator 4 rotates in the plus direction, that is, counter-clockwise in Fig. 2, the actuator 4 is caught directly by the left catching arm 54 and 51 so that also in this case the lever 322 receives a shifting impulse through the pin 32$. Said lever 322 moves the pin 329 away from the tip 320 of the hook 21! which is then pulled upwards by its spring 321 and releases the pawl 265 which is mounted on the end of lever 241. The spring 266 now rocks this pawl into the path of the swinging driving lever 291. The right end (Figs. 1 and 9) of the lever 241 is then rocked forwards, that is clockwise. If member 249 has not been set to its inoperative position (by the U-shaped member 259 at the last shifting step to the right), this motion is transmitted through the member 249 to the member 250 which will act upon either or none'of the step shifting levers 254 and 255, according to the position to which the shifting plate 250 was set. According to the setting of said plate the actuator 4 is shifted one step to the left or to the right or is not shifted at all.

As mentioned above, the shifting plate 250 is set to engage the right step shifting lever 254, when the lever 20I is in its position b and simultaneously the disconnecting lever 202 is in its right position as shown in Fig. 1 in full lines. On the contrary, the actuator 4 is shifted to the left, when the shifting plate 250 has been set to engage the left shifting lever 255 due to the fact that the lever MI is in its position a. (To what position the lever 202 is set is of no importance in thislast-mentioned case.) If the chief lever 20! is in its position b and simultaneously its disconnecting lever is set in its left position 1 the shifting plate 250 cannot actuate either of the step tabulating levers 254 or 255, and in such case the actuator is not automatically shifted.

It is to be observed that the hook 320 follows the hook 21I, when the latter is drawn upwards by the spring 321, after the lever 322 has received a shifting impulse. Then the hook 325 closes the contacts 334 so that the latter remain closed during the whole step shifting action. When the lever 241 is moved forwards, that is clockwise in Fig. l. the pin 213 acts on the earn 330 (Fig. 2) of the hook HI and presses it down to release the impulse lever 322. Thus, the hook 21I returns to its position of rest and is locked again.

When the actuator is shifted to the left to its end position as described above, further shifting to the left is checked by a stationary stop, say, by the wall 2I1 after the last shifting step. When the actuator is shifted to its end position at the right, the revolutions counter actuator 2I9 acts on the U-shaped member 259 at the last shifting step, so that the hook lever 249 is disabled and further shifting to the right is prevented.

Because the revolutions counter actuator 2I9 rotates in the same direction as the actuator 4 (on the condition that the nob 234 has not been set by hand) and the impulse lever 231 (Figs. 3 and 4) is, inoperative. short-cut multiplication may always be used, that is, the multiplication cleared, as described above.

may be carried out by a minimum of revoluti Thus, the numbers 9 may appear in the highest denominations of the revolutions counter when the machine is manipulated by means of the key 2, and the machine is not stopped automatically when the capacity of the product (in the accumulator L) is exceeded.

Ordinary division with. unlike rotation of actuator and revolutions counter actuator 3. The shifting plate 250 (Fig. 1) is rocked to the right by spring 253, independently of the position of the disconnecting lever 202. The plate 250 is consequently set to engage the right step shifting lever 254.

4. The lever 283 (Fig. 9) is rocked counterclockwise and no longer locks the pawl 215 on the lever 214.

5. The slide 31 i (Fig. 2) is shifted so that it no longer acts on the pawls 304 and 305 (Fig. 10).

Now the dividend is set in the actuator 4 by means of the amount keys 200 and the key I08 is depressed so that the actuator is tabulated to its extreme left position (see 11. S. Patent 2,243,075) The plus key 203 is now depressed by hand and this causes the dividend to be introduced into the accumulator and the actuator is automatically The revolutions counter is cleared by hand (see, for instance, U. S. Patent 2,188,748). Now the operator sets the divisor in the actuator by means of the keys 200, depresses the division tabulating key I30 to move the actuator to its extreme left position and initiates theautomatic division by depressing the division key 2. i

The tabulation of the actuator 4 to the left due to the manipulation of the key I96 moves the U-shaped member 25! (Figs. 1, 8 and 13) and the minus locking member 233 to the left, and the hook lever 249 is set to engage the projection 251. As mentioned above, the pawl 215 is now locked exclusively bythe lever 241.

The manipulation of the division key 2 starts the motor and the pin 30 is moved to its position (Fig. 6) and it moves the lever 234 so that the control plate 201 engages the multiplication key I (Figs. 1 and 2). When the motor runs, the driving lever 261 receives a swinging motion to and fro. Because the key 2 was depressed, the machine subtracts the divisor from the dividend, until over-draft occurs, that is, the capacity of the accumulator is exceeded; this rocks the tens transierhook I (Figs. 3 and 4) of the highest denomination upwards and this motion is transferred as a stopping impulse through the members 231 and I02 and causes the actuatorto stop in the following manner: When the lever I02 is thus swung in the direction of the arrow S (Fig. 21) it rocks counter-clockwise a stopping lever I 000 which is journalled on a stationary pin I00 I.

The pin I002 on this stopping lever then releases the hook 369 or 310 so that the slide 36 or 31 is drawn downwards by its spring 42. Then the projection 1003 of the slide releases the latch 45 or 46 from the guide member 33, which is then restored to its central position (position of rest), so that the actuator is stopped, as described in detall in U. 5. Patent No. 2,127,102. In minus oper-. ations the acuator 4 rotates clockwise in Fig. 2 and is consequently stopped by the right catching pawl 54 and the right catching arm 51. However it bounces back and strikes the left catching pawl 54 and the left catching arm 51 which is thus rocked. This causes the pin 32I to move the impulse lever 322 so that said lever receives a shifting impulse and its projection 323 releases the pawl 305; thus the division key 2 is released, re turns to its position of rest and would open the motor contacts 334. But when the lever 322 is racked, the pin 320 slides off from the projection {328 of the hook 21 I, which is thus liberated and drawn upwards by its spring 321. The hook 326 follows the hook 2H and would close the contacts 334 again. As a matter of fact the contacts are of the lever 241 to which the pawl 265 is pivoted is then rocked forwards, that is, clockwise, and this motion is transferred through the members 249 and 250 to the right step shifting lever 254 so that the actuator 4 is shifted one step to the right'to the next lower denomination. When the lever 241 moves forwards, that is, clockwise, the pin 213 acts on the curve 330 of the hook 21l and presses it down to release the impulse lever 322, Thus, the hook 21I returns to its position of rest and is locked there again. The contacts 334 remain closed during the whole motion of the lever 241, due to the cam 326a (Figs.,2, 2b) of the hook 326, which rests upon the pin 213. During said clockwise motion of the lever 241 the pawl 215.is free to pivot in a counterclockwise direction and is hence drawn by the spring 211 into the path of the driving lever 261. At the backward or counter-clockwise motion of this lever 261 the arm 214 is rocked backwards in Fig. 1 and pulls down the key I by means of the control plate 261 (Figs. 1 and 9). When the driving lever 261 is moved backwards, as just mentioned, it moves the lever 241 into its position of rest by means of the projection 241a thereof. The pawl 265 is then rendered inoperative due to the fact that the projection 269 of the hook 211 now in its position of rest acts on the projection 268 (Fig. 1). When later the driving lever 261 again is moved forwards, it rocks the lever 214 (Figs. 9 and 13) back again through its projection 214a. The projection 218 of the pawl 215 strikes the lever 241 and said pawl is released from the lever 261. The tabulating mechanism is new again in its position of rest, but the multiplication key I has been pulled down.

Thus, the forward motion of the driving lever 261 effects a shifting of the actuator, while the backward'motion of said lever pulls down the key I. Because the operations are thus distributed, the load on the driving mechanism is reduced.

As was mentioned above the multiplication key I is now pulled down and thus the machine starts for plus revolutions, that is counter-clockwise in Fig. 2. The pin 38 (Fig. 6) is moved to its plus position and via the lever 294 it sets the control plate 281 to engage the key 2. The plus revolutions of the actuator 4 are continued, until the number 9 in the highest denomination of the accumulator is changed to 0, that is, the overdraft is cancelled (over-addition) the tens transfer hook I00 upwards and causes the machine to stop (Just as described above for This rocks the minus revolution). The actuator 4 is now checked by the left catching pawl 54 and the left catching arm 51, the shifting impulse lever 322 is rocked and the operation of actuator shitting is repeated again, as described above for the minus revolution. Thereupon also the division key 2 is pulled down. Thus, the division is continued with alternate minus revolutions and plus revolutions and the actuator is shifted one step when the direction of rotation is changed, until the revolutions counter actuator 2 l9 reached the lowest but one denomination of the revolutions counter N. If the calculation began at an even denomi nation of the revolutions counter, say in the eighth denomination (which may be its highest denomination) the calculating operation is eifected in accordance with the following scheme:

Denominat l o n of revolutions counter---" 8 'l 6 4 3 2 i Direction of rotation of actuator4 When the actuator and the revolutions counter actuator 2 It are shifted to the lowest denomh nation, the revolutions counter actuator tit and its carrier 2% move the ii-shaped mom the right in Fig. i, so that the hcolk leve connected from the projection consequently no :lurther shifting; to the ht can be effected. The spring" lti tends to dr locking member @299 to the right in e". l, but the latter is locked by the which is in its minus position, shown in dotted lines in Fig. The key i is automatically pulled down and the calculation begins in". 'lhe lowermost denomination of the revolutions counter, the arm and Zilil being" set to the plus position, when the hey i is pulled down. This releases the member ileil which is drawn to the right in Fig. l by the spring 30! and stops in its position shown in Fig. 1. When after the necessary number oi revolutions of the actuator 4 the lever 32?; receives stopping impulse, which is transferred as a shifting impulse to the lever 241, in the manner described above, said lever 241 makes a stroke (is rocked). But now the hook 249 is disconnected from the projection 251 so that the actuator l is not shifted, and, in addition, minus locking member 299 looks the pawl 215 and consequently the key 2 is not pulled down. The machine has now been stopped and the revolutions counter shows the quotient. The division has been completely carried out also in the extreme right or lowest denomination of the revolutions counter, and a positive remainder (or possibly no remainder) appears in the accumulator.

However, the division may also begin at an odd denomination of the revolutions counter, say in accordance with the following scheme:

Denomination of revolutions counter 8 7 6 5 4' 3 2 1 Direction of rotation of actuator The calculating operation is eflected as described above until the moment in which the revolutions counter actuator 2H! arrives at the lowthe minus est but one denomination of the revolutions counter. As is evident from the scheme above, in this denomination the actuator 4 makes one or more revolutions and the arm 294 is in its position shown in Fig. 6. When thereafter the revolutions counter actuator H9 and the actuator 4 are shifted to the lowest denomination, the U- shaped member 259 is moved to the right in Fig. 1, and also moves the member 299 in the same direction through the spring 30|. However, the mechanism is so constructed that at the motion of the lever Ml the pawl 216 snaps in, before the member 299 has reached its locking extreme right position. Thus, said member engages the projection 21B of the pawl 2M and consequently the key 2 is pulled down by the lever 2w by means oi the control plate Rel. This causes the projection :l'lt to slide off the edge 1293a oi the member 299, which then moves into its locking position. Im-

mediately at the start oi the machine (for the 'The control plate is rocked to engage the multiplication key When so many revolutions have made in the minus direction that the capacity 01" the accumulator is exceeded and an overdraft occurs, the highest denomination of the accumulator moves from 0 to 9, the machine is stopped as described above, and a step shifting impulse is initiated. This causes the lever Ml to be rocked again, but the hook lever Mil is inoperative and consequentl the actuator t is not shifted, But the hey i is pulled'down by the control plate 231, because the pawl Tilt is free. Thus, the actuator t is started in the plus direction, the reversal lever tilt is reversed (to its plus position) and the member Willis allowed to enter its locking position. The actuator makes one plus revolution so that the numbers in the highest clenominations of the accumulator are moved to 0 and thus the over-draft is cancelled. Now the machine is stopped and thus a step shifting impulse is initiated, but it has no effect and the key l and 2 are not further pulled clown auto matically. The division is completed; the quotient has been calculated down to the lowermost denomination of the revolutions counter and the remainder is positive (or zero) In Fig. there is shown a pawl 500 which in ordinary manner prevents more than one key from being pressed-down simultaneously. This pawl is journalled on a pin 502 secured to a part 50! of the machine frame.

The division may also be stopped by depressing the lever 358 (Fig. 10) by hand. For this purpose said lever should be extended outwards through a slot in the machine casing. When said lever 358 is pressed down, the actuator 4 is cleared and this stops the machine in the manner described in U. 8. Patent 2,068,899.

Positive division with like rotation of actuator and revolutions counter actuator The control lever 20! is moved into its position c for division. Then the knob 234 is moved downwards and forwards by hand in the direction of the arrow in Fig. 3 and this sets the revolutions counter actuator 2|! to rotate in the same direction as ther'actuator 4. By means of the amount keys 200, the dividend is now entered in

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