US1930475A - Calculating machine - Google Patents

Description

Oct. 17, 1933. E. v. GusTAFsoN ET AL CALCULATING MACHINE Fi'led Dec. 21, 1928 10 Sheets-Sheet l 7, 1933- E. v. GUSTAFSSON ET AL I v 0,

CALCULATING momma Filed Dec. 21 1928 10 Sheets-Sheet 2 Oct 7, 1933- E. v. GusTAFssoN ET AL 1,930,475

CALCULATING MACHINE Filed Dec. 21, 1928 1o swam-sum a Oct 1933- E. v. susTAFssoN El AL 1,930,475

CALCULATING MACHINE Filed Dec. 21, 1928 10 Sheets-Sheet 4 a Eng." 7

7 Oct. 17, 1933.

E. v. GUSTAFSSON ET AL 1,930,475

CALCULATING MACHINE 10 Sheets-Sheet 5 Filecj Dec. 21, 1928 flag]? (Jct- 1933- E..V. GUSTAFSSON ET AL 7 CALCULATING MACHINE Filed Dec. 21, 1923 i0 Sheets-Sheet 6.

1 III l Oct. 17, 1933. Q E. v. GUSTAFSSON El AL 1,930,475

CALCULATING MACHINE Filed Dec. 21, 1928 10 Sheets-Shet 7 Oct. 17, 1933; E. v, GUSTAFSSON ET AL 1,930,475

CALCULATING MACHINE -Filed Dec. 21, 1928 10 Sheets-Sheet 8 fave/12 m: MI "4 Avg/f Oct. 17, 1933. E. v. GUSTAFSSON ET AL 1,930,475

CALCULATING MACHIQE Filed Dec. 2 1, 1928 10 Sheets-Sheet 9 Patented Oct. 17, 1933 UNITED STATES, PATENT OFFICE I Our invention relates to calculating machines and particularly to that class known as ten-key CALCULATING MACHINE 4 Application December 21, 1928, Serial No. 327,587, and in Sweden December 23, 1927 48 Claims. (Cl. 235-) calculating machines, that is calculating machines having only one key for each numeral.

The principal object of the inven vide a calculating machine of the type described tion is to prowhich is simple in construction and operation,

is durable. and is small and compa Our new calculating machine comprises a setting-up mechanism or selector operated by means of numeral keys, a calculating mechanism combined with a total register and operated by said setting-up mechanism or selector and several control keys and a handle stroke counter or quotient register controlled dec selector and digitally by the number f pulls on the handle.

imally by the The calculating mechanism of our new calculating machine comprises a plurality of identical units each comprising two main-calculating members co-operating with a result member and so formed that a relative movement between them gives a result of a size determined by the size of said movement. This relative movement may be effected by the two main calculating members alternately forming a reaction base or support. The two main members may be combined with other members so as to form what.may be termed a differential gearing adapted to transfer to said result member the movement determined by the setting-upmechanism or selector, in a direction corresponding to the mode of calculation.

denomination.

The'handle stroke counter of our new calculating machine is adapted to record in addition and 'substraction the total number of items added or subtracted, respectively, and to, denote in multiplication the multiplier. and in division the quotient.

An important feature of our invention resides further in such an arrangement and construction of the setting-up mechanism 'orselector that the number set up can be read; or: directly in said selector, thus rendering ii -separate indicating register superfluous.

The invention is illustratedin th ing drawings, in which:-

e accompanymeans.

Figs. 1 and 2 illustrate somewhat diagrammatically the principle upon which the invention is based.

Fig. 3 is a perspective view of the machine.

Fig. 4 is a front View of the machine, the casing thereof being omitted;

Fig. 5 is a right side view of themachine with the casing omitted.

Fig. 6 is a view in detail of the escapement mechanism of the selector.

Fig.7 is a view in detail of the selector zeroizing Figs. 8 and 9 show a tongue of theselector in two projections.

Fig. 10 is adetail view of one unit of the calculatingmechanism.

Fig. 11 is a view seen from above of Fig. 10.

Fig. 12 is a view seen from below of Fig. 10, three consecutive units of the calculating mechanism being shown.

Fig. 13 is a detail view of an arm supporting the shifting mechanism.

Fig. 14 is a detail view of the tens transi er pawl of the calculating mechanism.

Fig. 15 is a detail sectional view of the controlling devices of the calculating mechanism and the quotient register. r

Figs. 16 to 20 inclusive are detail views of different elements of said devices.

Fig. 21 is a front view of the quotient register.

Fig. 22 isa right side view of said quotient register.

Fig. 23 is a detail view of one unit of said register.

Fig. 24 is the corresponding front view.

Fig. 25 is a plan view illustrating the general arrangement of the different keys. I

Fig. 26 shows a modified embodiment of the calculating mechanism.

In the following description the expressions right, "left", fore and rear refer to the machine as seen from the key-board. Theexpressions clockwise direction and counter- -clockwise direction" refer to the machine as seen from the key-board or from the right hand side.

each provided with a number of teeth which is equallydivisible by ten, the gear 11 meshing with one of said gear wheels, for instance 13.

These two gears are loosely mounted on a shaft 17 on which also other corresponding members co operating with other numeral wheels 11 are loosely mounted. Loosely mounted on said shaft 17 is also a lever 19, one for each pair of wheels 13, 15 and carrying two gear wheels 21 and 23 in mesh with each other. As shown in Fig. 2, these gear wheels 21 and 23 have a greater width than the wheels 13 and 15 and each engage one of same, 21 engaging 13 and 23 engaging 15. The gear wheels 13, 15, 21 and 23 form together what may be termed a differential gearing. Lever 19 is by means of a spring 25 connected with a manmuvering arm 27 swingably journalled on the shaft 17, said spring 25 resting against a plate 29 connected with said arm 27 and having such an initial tension that on turning the I arm 27 in the direction of the arrow shown on said arm in Fig. 1 the lever 19 together with differential gears 21 and 23 will follow this rotation, until stopped by one of selector tongues 31. A continued rotation of the manceuvering arm 27 for the setting of other groups results only in a continued tensioning of the spring 25. On the return movement of the arm 27 the plate 29 restores the lever 19 into normal position, abutting against said lever as at 33. The selector tongues 31 are controlled from the key-board of the machine in any suitable manner.

The wheels 13 and 15 are controlled by locking means (not shown in Figs. '1 and 2) in such manner that said wheels are alternately locked, one wheel on the forward stroke of the manoeuvering arm 27 and the other on the return stroke of said arm.

The operation is as follows, it being assumed that wheel 15 is locked and wheel 13 freely rotatable during the forward stroke of the arm 27 whereas wheel 13 is locked and wheel 15 freely movable during the return stroke of the arm.

When arm 27 is turned in the direction of the arrow, wheel 23 in mesh with locked wheel 15 is rotated, driving in turn by means of wheel 21 the lovable wheel 13 in mesh with numeral wheel 11. This latter wheel 11 will, consequently, berotated, until lever 19 strikes the projected selector tongue 31 whereby the movement in this group is stopped. Numeral wheel 11 will then show the numeral corresponding to the projected tongue, the locked wheel 15 serving as a reaction base or support during this movement. When arm 27 which is moved further in order to set other groupsin the machine reaches its upper end position, wheel 15 is released and wheel 13 stopped. On the return stroke of arm 27 wheel 21 will rotate on locked wheel 13 which latter serves as a reaction base or support for this movement, said wheel 21 driving by means of wheel 23 wheel 15 in opposite direction to that in which wheel 13 was rotated, and when the arm 27 has reached its starting position both wheels 13 and 15 have been rotated through equal angles. The rotation of wheel 15 during this second stage is not, of course, transferred to numeral wheel 11, as this wheel only engages wheel 13 which is now locked.

If at the beginning of the movement of arm 27 wheel 13 is locked, wheels 21 and 23 and, thus, wheel 15 will be rotated in opposite directions as before. The numeral wheel 11 remains then unactuated during this-first stage of the movement, but when arm 27 is returned, it will be rotated in opposite direction as before through an angle corresponding to the numeral set up in the selector. Consequently, the direction of rotation of numeral wheel lldepends upon which wheel 13 or 15 is locked at the beginning of the movement of arm 27, that is to say the desired mode of calculation, for instance addition or subtraction, can be obtained by locking one of the wheels 13 or 15 according to the order in which the numerals are arranged on the numeral wheel 11.

We will now proceed-to describe a constructional form of a calculating machine built according to the principle above explained, beginning first with the embodiment shown in Figs. 3 to 25, inclusive.

A calculating machine according to the invention comprises essentially the following main parts: the key board A including ten numeral keys and a plurality of control or shift keys, the setting-up mechanism or selector B, the calculating mechanism C and the handle stroke counter or quotient register D. The general design of the machine is clearly shown in Fig. 3. As shown the machine is covered by a casing 10 in which openings are provided for the different keys and windows 12, 14 and 16 for showing the number set up in the selector, the result in the total register combined with the calculating mechanism and the number registered in the quotient register, respectively. The machine is operated in known manner by means of a handle 18, operating the main driving shaft 162, it being understood, however, that it may also be operated automatically, for instance by means of an electric motor. In this figure is also shown a wing screw 20 for clearing the quotient register, this being effected in well-known manner,

' The key-board The key-board A (see especially Fig. 25) comprises ten numeral keys corresponding to the numerals 0 to 9 inclusive, further a subtraction key 22, a multiplication key 24, a division key 26, a naught key 28 for advancing the selector one decimal step to the left, a back space key 30 for resetting the selector one decimal step to the right, and a zeroizing or blanking key 32 for clearing the total register. The numeral keys, the naught key 28, the back space key 30 and the zeroizing key 32 are in well-known manner spring-actuated so as to be automatically restored to starting position when the key tab is released from the finger pressure. The subtraction key 22, the multiplication key 24 and the division'key 26 are also spring-actuated but are arranged in well known manner so as to be locked in depressed position on depression and released and restored to normal position first after a second depression.

Each of the numeral keys as well as the naught key 28 is connected with a key lever 34, said levers being at their free ends at 36 each connected with a cord 38, the other end of which engages a hammer in the selector in a manner to be described later on in'connection with the description of the selector, it being stated at this point that the cord 38 of the naught key 28 engages the same hammer of the selector as that of the key 0. The arrangement and operation of the remaining keys will be described in the following.

The selector The setting-up mechanism or selector B consists of a slidably mounted carriage comprising an upper plate- 48, a lower plate 50 and two side plates 52 and 54. Suitably journalled in this carriage are two pairs of guiding rollers 56, 58, 60 and 62, the upper pair 56, 58 rolling on an upper guide 44 and the lower pair 60, 62 ona lower guide 46, said guides 44, 46 being secured transversely of the machine in the rear part thereof to r the main side frames 40 and 42. In plates 48 and 50am rows of openings, the openings in the one plate being in alignment with those in the other. Each longitudinal row (seen in the longitudinal direction of the machine) contains ten openings, the number of such longitudinal rows depending on the desired decimal capacity of the machine. Guided in each pair of openings thus formed in Y the two plates 48, 50 is a tongue 64 resting normally so as to position a notch 66 therein on the lower plate 50 of the carriage with its upper edge at the same level as theupper surface of the upper plate 48. The tongues 64 are each provided with a recess 68 limited at the top by a laterally projecting lug '70. The shape of the tongue 64 is clearly shown in Figs. 8 and 9.

Secured to a partition wall 72 disposed longitudinally of the machine is a bridge piece 74, and journalled on saidbridge piece are a plurality of hammers '76 in the form of two-armed levers. In the embodiment shown there are ten such lvers '76. Secured to one end of said ham- I mers 76 is one of the cords 38 connected with the key levers 34, whereas at their other ends the hammers 76 are each provided with a head 78 guided in a suitable slot in a block 80 secured to the partition wall 72. At the front of each of the ten transverse rows of tongues 64 a rod 82 issecured to the main side frame 40 and extends into an opening in the left lateral plate 52 of the selector carriages. -;,The selector carriage is advanced step by step vtothe left by means of the following escapement mechanism, the depression of any of the numeral keys or of the naught key 28 effecting the movement of the selector one step to the left. Secured to 'the selector carriage in any suitable manner is a rack 84 see especially Figs. 4 and 6) Mounted at the upper end of a link 86 of the transferring means of the back space key 30 below said rack 84 is a stud-8'7 on which a pawl 88 is pivotally mounted.'.1Mounted at both sides of the machine in any suitable manner (see Fig. 25) is a stud 90 A-cor'd 164i engages the-other end of said lever 102'and is; atijits otnerggnd connected with the above-irn enti oned'pawl .88k as sat-.106. (30-.

operating with said pawl is another pawl 108 pivotally journall as, 8113 1107111 bl'acketf5(18 secured to the partition wall; 72. 5:; dog 110fon the latter catching under the. pawl88. 'A spring 112 presses the pawl 110 normally in engagement with the rack 84, whereas the pawl 88 is nor-.

mally out of engagement with said rack 84. .When

on depression of any of the numeral keys or of the naught key 28 a pull is exerted in cord 104 by means of lever system 92, 96, 102, pawl 88 is swung into a tooth space of rack 84 and presses simultaneously by means of dog 110 pawl 108 out of V engagement. with said rack .84.

The selector carriage actuated .in a manner to be later described by a spring 114 tending to move the carrow of tongues 64 of the selector is moved into riage to the left is thereby moved in this direction through a distance corresponding to approximately half a pitch of the rack 84, until pawl 88 prevents its further movement. Upon the release by the finger of the depressed key pawl 88 is brought out of engagement with rack 84 at the same time as pawl 108 actuatedby spring 112 is moved into the next tooth space of said rack 84 causing spring 114 to move the selector carriage the remaining half escapement, i. e. half a pitch to the left, until pawl 108 steps the movement. The pitch of the rack 84 is so chosen that upon the movement of the selector carriage through one step to the left the next longitudinal alignment with the heads '78 of the hammers 76.

Upon depression of any numeral key or of the naught key 28 corresponding tongue 64 is pressed out through the corresponding opening in the upper plate 48 of the selector carriage by the head 78 of the hammer 76 in question. The tongues 64 pressed out may be observed through the window 12 in the casing 10. By this arrangement very simple means is obtained to indicate the number set up in the selector which, of course, is of great importance, especially in ten-key calculating machines, as the operator can correct any mistake before the number is thrown into the total register. Upon the movement of the selector in the manner above described the tongue 64 pressed out rides up on corresponding rod 82 on which it is then hanging with its lug 70. Upon the return of the selector in the manner to be described tongue 64 is no longer supported by rod 82, so that it falls down again in its normal position resting with its notch 66 on the lower plate 50 of the selector carriage.

If for some reason or other the tongue 64 does not-fall down by itself in normal position, means are provided to secure this, said means compris- 115 ing a lever 116 (see especially Figs. 4 and 5) arranged above the selector tongues 64 and pivotally journalled in brackets 118 secured to the right side frame 42. At its right end lever 116 is provided with a downwardly extending tail 122 120 'and at its left end with an inclined surface 120, said end reaching a little distance beyond the first left row of tongues 64, when the selector is in its starting position. If upon the return of the selector any tongue does not return to starting position, it will abut against inclined surface 120 causing as a rule the tongue to be pushed home. If-the tongue 64 is not depressed, it will lift the lever 116 and when then at the end of the pushing home of the selector carriages the latter strikes against the tail 122 of the lever 116, said lever is pressed downwardly and depresses in turn any tongue 64 which is still projecting beyond the upper plate 48 of the selector carriage.

The selector is'zeroized or cleared by the following means (see especially Figs. v4 and 7) Journalled in a rear frame 124 and a fore frame (not shown) of the machineis a shaft 126 and. secured to said shaft at the rear end thereof is abell crank lever 128, 129. Rotatably mounted 40 on said shaft 126 is a-link 180 pivotally con nected at its free end at 131 with-another link 132 which at its other end is pivoted on the same stud which forms the bearing for guiding roller 62. The arm 128 of lever 128, 129 is at its free 4 end by meansof a spring 136 connected with link i 130 as atl38, whereas the other arm 129 termi- .nates in a laterally projecting abutment 140 normally engaging the link 130. Journalled on a stud 141 secured to the machine frame is a double armed lever 142, the one end of which is connected with the side frame 42 by a spring 144, whereas. its other end is formed as an abutment 146 for the purpose to be described later on. The lower surface of the lever 142 is formed as a cam and co-operates with a pin 148 formed on the link 130. Further the lever 142 is at the end thereof connected with the machine frame provided with a shoulder 150 lying in the starting position of the selector carriage immediately above the surface of abutment 140 co-operating with the link 130.

Pivotally mounted on the machine frame at 149 (see especially Fig. 5) in the rear part of the machine is an arm 151 provided with a tooth 152 and actuated by a spring 153. At its free end the arm 151 is provided with an abutment 155 which by the spring 153 is pressed into engagement with a cross bar 228 to be described later on. When upon the forward stroke of the operating handle 18 said cross bar 228 is rotated in counter-clockwise direction (see Fig. 5), the arm 151' is drawn upwards under the action of the spring 153 causing the tooth 152 to engage rack 84 and lock the selector carriage in set position. When at the end of the return stroke of the operating handle 18 the cross bar 228 is again brought into engagement with the abutment 155 of the arm151, the tooth 152 disengages the rack 84 thus releasing the selector carriage.

Secured to shaft 126 at the fore end thereof is an arm 154 ca rying at its free end a pin 156 projecting through an elongated slot 158 in a link 160, the other end of which is pivoted on a stud 159 secured to the free end of a lug 164 of a part 232 fixed on the main driving shaft 162.

The operation is as follows: When a given item is set up in the selector, link 130 has been rotated in counter-clockwise direction by means of link 132 through an angle corresponding to the number of numerals in the item set up. Evidently bell crank lever 128, 129 secured to shaft 126 has also taken part in said rotation by means of spring 136 connecting said lever 128, 129 with link 130 and also arm 154 secured to said shaft 126, the

, pin 156 of said arm 154 sliding in slot 158 in link 160. During this rotation pin 148 is sliding on the lower cam surface of lever 142, said cam surface having such a form, that, as soon as abutment 140 has come clear of shoulder 150 of lever 142, the latter is drawn'downwardly a given distance by means of spring 144. At the beginning of the forward stroke of the operating handle the selector is locked by the tooth 152 engaging the rack 84. When then the operating handle is turned forwardly, link 160 is lowered, until pin 156 on arm 154 engages the upper surface of slot 158 which, of course, will happen immediately, if the decimal capacity of the machine is entirely utilized. Then shaft 126 is turned by link 160 in clockwise direction in which rotation bell crank lever 128, 129 secured to said shaft 126 takes part against the action of spring 136 which is correspondingly tensioned. When the operating han- .dle 18 has attained its dead center, abutment 140 of bell crank lever 128, 129 engages shoulder .150 of lever 142 which has been drawn downwardly a slight distance by spring 144, causing said lever 128, 129 to be locked. Link 130 is still in its angularly shifted position, as the selector carriage is locked by tooth 152. At the end of the return stroke the selector carriage is released by tooth 152 and returned byspring 136 into starting position, bell crank lever 128, 129 being again released from engagement with shoulder 150 by lever 142 being lifted by pin 148 against the action of spring 144. The spring 114 which as mentioned'above effects the step-by-step movement to the left of the selector carriage, is at its one end fixed to the partition wall 72 at 166 and at its other end to a lug 168 of link 130, said spring 114 being weaker than spring 136 so that it is tensioned upon the return of the selector into starting position under the action of spring 136.

The calculating mechanism The calculating mechanism C is disposed in the left part of the machine and comprises a plurality of identical units each comprising a pair of gear wheels 170 170 (see especially Figs. 5, 10 and 11) loosely mounted on a shaft 169 secured to the left side plate 40 of the machine frame and to the partition wall '72, said wheels having each a number of teeth equally divisible by ten. Loosely journalled on the same shaft 169 is a holder 172, one for each unit, and journalled in each of said holders 1'72 are two gear wheels 174, 176 in engagement with each other. In the machine illustrated which is adapted to be operated by an angular rotation of the operating handle 18 of /5 of a revolution, the gear wheels 170 1'70 are each provided with fifty teeth, whereas the gear wheels 176, 174 have each ten teeth. The latter have greater width than each of gear wheels 170", 170 and each of them is in permanent engagement with one of the gear wheels 170 170*, 174 with 1'70 and 176 with 170 Together with the pair of gear wheels the gear wheels 174, 176 form what may be termed a differential gear. Gear whfeel 176 is rigidly connected with another gear wheel 178 engaging a numeral gear wheel 182 provided with a numeral plate 180 and also rotatably journalled in holder 172. The numeral wheels 182 form together the total register. Further holder 172 is provided with a bent arm 184 which upon rotation of holder in a manner to be described is swung, until it strikes any projecting tongue 64 in the selector. Arm 184 is so arranged in relation to tongues 64 of the selector as to pass the unactuated tongues by going through the recesses 68 in same.

Rotatably journalled on shaft 169 is an arm 186 for each unit, said arm carrying at its free end an abutment 188 normally in engagement with a cross bar 190 fixed transversely of the 12.; machine. The arm 186 is shown in detail in Fig. 13. Rotatably journalled in said arm about a stud 192 is a pawl 194 provided with two pins 196, 198 so arranged as to engage alternately a tooth space in one or other of gear wheels 170 170 when pawl 194 is swung in a manner to be described in the following. At its one end pawl 194 is bifurcated and in the opening of the fork there is a cross bar 200 common to all pawls 194 and carried by two arms 202' (see Fig. 4). one at each 13.5 side of the machine which arms are pivoted on studs 204 secured to the machine frame. Journallcd on the stud 204 at one side of the machine is another arm 206 rigidly connected to arm 202, and at the free end of said latter arm 206 is a roller 208 controlled by a cam disk fixed on main driving shaft 162. The arrangement and construction of said pawl 194 is such that always one of gear wheels 170 1'70 is locked to arm 186 and that, when the pawl is shifted in the manner to be described the locked wheel is not released, until the other wheel has been locked, that is the pawl 194, one pin 196 of which engages a tooth space in one of the wheels, for instance 170, can not be swung out of engagement with this wheel, until 150 the other pin 198 has been brought into engagement in a tooth space in the other wheel 170.

The calculating mechanism is operated by following means:

Fixed in the upper part of holder 172 is a spring 210, the other end of which is fixed at the one end of an arm 214 pivoted on'a stud 212 secured to the machine frame. The upper surface of said arm 214 forms a cam having a recess 220 between two cam surfaces 216, 218. Co-operating with said cam surfaces 216, 218 and said recess 220 is a roller 222 mounted at the free end of an arm 224 fixed on main driving shaft 162. The cam surface 216 has the form of a circular arc having its center coinciding with the center of shaft 162, and, consequently, on rotation of shaft 162 roller 222 will roll upon cam surface 216 without causing any turning of arm 214, until roller 222 falls into recess 220 and strikes the edge of cam surface 218 which latter is so formed that on continued rotation of shaft 162 arm 214 is swung in clockwise direction (see Fig. causing the springs 210 to be further tensioned and thereby tending to rotate holders 172 in opposite direction.

Loosely journalled on shaft 169 at each side of the machine is a bridge 226, said bridges being in the rear part of the machine connected with each other by means of a cross bar 228 resting in the starting position of the machine against all holders 172. Other end of the one bridge 226 is pivotally connected with arm 214 by means of a link On the forward stroke of the operating handle the bridges 226 will, consequently, be

= turned in counter-clockwise direction, whereby cross bar 228 willv be removed from all holders 1'72 which, actuated by their springs 210, will also be turned in counter clockwise direction, until they are stopped by the actuated selector tongues 64. On the return stroke of the handle cross bar 228 will restore all holders 1'72 into starting position.

The pawl 194 is controlled by the following means (see especially Figs. to Fixed on main driving shaft 162 is a triangular disk 232.

Swingably mounted on studs 234 and 236, respectively, in two corners of said disk 232 are saw- tooth pawls 238 and 240, respectively, said pawls being at their free end connected by a spring 242. The pawls are each provided with a pindesignated 244 and 246, respectively, said pins cooperating with a cam disk 248 (see Fig. 17) rotatably journalled on the main driving shaft 162, said cam disk having for the control of the pawls two cams, 250 and 252. The latter cam 252 terminates in an arm 254, connected at its free end with a link 256 which in turn is connected with the subtraction key and the division key 22 and 26, respectively, in a manner. to be described. Rotatably mounted on shaft 162 is further a ratchet disk 258 (see Fig. 18) cooperating with the saw-teeth of the pawls 238, 240, said disk being provided with five recesses as the machine is adapted to be operated by an angle of rotation of the operating handle of 5 of a revolution. Rigidly connected with said ratchet disk 258 is a cam disk 260 (see Fig. 19) having also five recesses and co-operating with the above mentioned roller 208 on arm 206. In the position shown in Fig. 5 in which the machine 7 is set for addition or multiplication disk 232 ,to-

gether with pawls 238, 240 will on the forward stroke of the vhandle 18 be turned in counterclockwise direction, ratchet disk 258 and cam disk 260 not taking part in this rotation on account of saw-tooth of pawl 240 sliding on ratchet disk 258 and saw-tooth of pawl 238 also doing so, as said pawl, when in the course of the rotation it falls down on ratchet disk 258 by pin 244 leaving cam 250, is not in register with anyrecess in the ratchet disk 258. When operating handle is in its dead center, pawl 240 has been turned through such an angle that its saw-tooth engages the next recess in ratchet disk 258, and on the return stroke said ratchet disk 258 and, consequently, also cam disk 260 are turned in clockwise direction, the roller 208 riding up on the cam of the disk 260 lying nearest to the left,v

thereby causing a shifting of pawl 194, so that in Fig. 10 pin 196 is brought out of engagement with gear wheel 170 and pin 198 into engagement with gear wheel 170 When at the end of the return stroke of the operating handle -18 roller 208 engages the next recess of cam V will be shifted. -When the handle has reached its dead center pin 246 has ridden up on cam 252 so that the saw-tooth of pawl 240 is brought out of engagement with ratchet .disk 258. In this position roller 208 has engaged the next recess in cam disk 260 so that pawl 194 has been restored into original position. During the return stroke of the handle the teeth of both pawls .238, 240 will slide on ratchet disk 258 which, consequently, does not partake in this rotation. As the saw-tooth of pawl 238 is still in engagement with ratchet disk 258, the parts are in their original position, when the rotation of the handle is completed.

In order to permittens transfer in the calculating mechanism the following means are provided (see especially Figs. 10, 12, 13 and 14). Loosely journalled on shaft 169 at each side of the machine is an arm 262, which arms in their free ends are connected with each other by means of a cross shaft 264. Loosely mounted on said shaft 264 are pawls 266, so called tens transfer pawls, one for each unit of the calculating mechanism. One pawl 266 is shown in detail in Fig. 14. Shaft 264 projects through an elongated slot 268 in each of the side frames 40 and 42 and extends a little distance beyond said frames. Normally resting against the cross shaft 264 is a downwardly extending arm 270 integral with bridge 226. Arm 262 is by means of a spring 272 connected with the machine frame as .at 274. Formed at the free end of tens transfer pawl 266 is an opening 276 having two bearing surfaces 278 and 280 arranged at a distance from each other in the peripheral direction of the wheels 170, 1'70 corresponding to half a pitch. The distance between the two extreme positions of, shaft 264 in slot 268 cor-' responds also to half a pitch. Projecting into opening 276 is a stop 282 formed at the end of the arm 186 and connected by a spring 284 with the fore part of tens transfer pawl 266. "The upper edge of pawl 266 is provided with two lugs 286, and gear wheels 170, 1'70 are each provided with a pin 288 and 290, respectively, for every tenth tooth. In the present case where these wheels have each fifty teeth there are, consequently, five pins 288 or 290 on each wheel. The tens transfer pawl 266 is arranged in such manner that its lugs 286normally are located in the path of both said pins 288 and 290 of the pair of gear wheels 170 1'70 of the next lower denomination unit, that is each tens transfer pawl 266 controls the position of the arm 186 of the next higher denomination unit. As seen in Fig. 10 in the initial position of the parts, pin 288 on wheel 170" is located immediately to the left of lug 286 and pin 290 on wheel 1'70 immediately to the right thereof.

The embodiment of the machine above described is arranged in such manner that the angular distance between two consecutive tongues 64 in the selector corresponds to onehalf pitch and that in the starting position of the machine the arms 184 terminate a distance in front of the first row of tongues 64 corresponding to onehalf pitch.

The calculating mechanism operates in the following manner: On rotation of the operating handle 18 in counter-clockwise direction (Figs. 3 and 5), the bridges 226 with the arm 2'70 and the cross bar' 228 are turned, by means of link 230 and arm 214, in counter-clockwise direction and at the same time the springs 210 are further tensioned by the movement of said arm 214, so that all holders 1'72 will be free'to turn in counterclockwise direciion, until their arms 184 are stopped by any projecting tongue 64. One gear wheel, for instance 1'70, is locked by pin 196 (see Fig. 10), whereas the other 170 is freely movable. However at the beginning of the forward stroke of the operating handle, all differential gears 170 170 1'74, 176 are turned, through the intermediary of the springs 210 and the holders 172, as unitary bodies, on account of the friction between said gear wheels and no external friction to resist any of them separately, in counter-clockwise direction a distance corresponding to one-half pitch. This distance is determined by the movement of shaft 264 which by means of arms 262 and the spring 2'72 is drawn to the right one-half pitch (Fig. 10), until it occupies its extreme position to the right in slot 268, resulting in that tens transfer pawl 266, stop 282, arm 186, pawl 194 and, as above described, the differential gears as a whole are turneda corresponding angle in counter-clockwise direction, the stop 188 of arm 186 then being one-half pitch away from cross bar 190 and all arms 184 of the holders 1'72 being immediately in front of moved step by step. As an alternative the initial one-half pitch movement, including arms 262, shaft 264 and slot 268, could be avoided and instead thereof the cross bar 190 be made-movable one-half pitch in clockwise direciion. This onehalf pitch movement of arm 186 is necessary in any case for tens transfer operation, as will be explained later. From the above it will be clear, that said initial one-half pitch movement of all the enumerated parts or of the cross bar 190 alone has no influence on the counter wheels 1'78, 182, 180 as these will not change'their position relatively to the differential gear. The same is the case, when during the return stroke of the handle 18 the same one-half pitch movement is effected to restore the parts to their relative initial position, inasmuch as the holders 1'72 and the arm 2'70 then are turned simultaneously in clockwise direction the final one-half pitch movement, so that there will be no relative movement beLween the wheels of the differential gears.

When now after said initial one-half pitch 'empty movement, the holders 1'72 are further turned by their springs 210, until they are stopped by a projecting tongue 64, differential wheel 1'74 in mesh with gear wheel 170 rolls on the latter, being locked, and is thereby turned in counter-clockwise direction, said rotation being transferred to the other differential wheel 1'76, which, consequently, is turned in clockwise direction and in turn rotates the movable wheel 1'70 in counter-clockwise direction being in permanent engagement with the latter. On account of the natural action of the differential gear, wheel 1'70 will be turned twice as many pitches as the pertaining holder is turned. Considering, for instance, the holder stands still and wheel 174 is turned say two pitches, then wheel 1'76 and consequently wheel 1'70 is also turned two pitches. As however, as in the present case in order to turn wheel 1'74 two pitches, holder 172 must be turned two pitches, wheel 170 is not only turned the above stated two pitches but on account of the two pitches movement of the holder 1'72 two further pitches, that is in all four pitches or twice as much as the holder. The movement of wheel 1'76 is transferred by gear wheel 1'78 to numeral wheel 182, which, consequently, will be turned in counter-clockwise direction the same number of pitches as the holder 1'72. A further rotation of arm 214, after arm 184 having been stopped by the projecting tongue 64, will only cause further tensioning of spring 210. When the handle has reached the end of its forward stroke, numeral wheel 182 has, consequently, been rotated half the number of teeth corresponding to the numeral set up in the selector, depending on the above mentioned relation between the angular distance between the tongues of the selector and the pitch, said rotation having taken place in counter-clockwise direction. Now pawl 194 for all units is shifted in the manner above described, so that gear wheel 1'70 is released and gear wheel l'70 locked. During the return stroke of the operating handle, differential wheel 176 in mesh with ear wheel 170 now locked, will roll on the latter and is turned in the same direction as before, thus in clockwise direction, causing numeral wheel 182 to be turned in the same direction, that is in counter-clockwise direction, and through the same angle as before, simultaneously as movable wheel 1'70, will be turned in clockwise direction twice the number of pitches as holder 1'72 by means of differential wheel 1'74, that is in opposite direction to that of wheel 1'70 during the forward stroke of the operating handle. At the end of the return stroke of the handle 18 arm 2'70 returns shaft 264 back to its original position to the left in slot 286 against the action of spring 272 causing arm 186 to be brought into engagement with cross bar 190 and the differential gears as unities to be turned through an angle in clockwise direction corresponding to one-half pitch. When the operating handle 18 has reached its starting position, gear wheels 1'70, 1'70 have, consequently, been turned through the same angles but in opposite directions, and numeral wheel 182 has been turned through an angle corresponding to the number of teeth represented by the numeral set up in the selector.

If from the beginning for instance for effecting subtraction operations gear wheel 1'70 is locked and gear wheel 1T0 is movable the directions of movement will, of course, be reversed.

When a' tens transfer is to take place, lug 286 of tens transfer pawl 266 is actuated by a pin 288 or 290 of that one of gear wheels which is not locked. On account of the working action of the .differen'tialgear the tens transfer is divided into two separate movements in a similar manner as the normal calculating operation is effected, the first half of the tens transfer operation taking place during the forward stroke of the'operating handle 18 and the other half during the return stroke, as will be explained later by way of an example. By said engagement of the lug 286 by the pin 288 or 290 tens transfer pawl 266 is pressed downwardly, so that stop 282 on arm 186 which initially has been in engagement with bearing surface 2'78 of pawl 266 is now brought into engagement with bearing surface 280 causing movement of arm 186 through one-half pitch in clockwise direction. Thereby pawl 194 of unit of the next higher denomination is moved through a corresponding angle carrying with it the locked wheel in said unit which, consequently; is turned through the same angle, that is one-half'pitch. If it is assumed that a tens transfer is to take place in the case described above in detail, in which gear wheel 1'70 was first locked, said wheel will, consequently, be turned one-half pitch in clockwise direction causing rotation of differential wheel 1'74 in mesh with wheel 1'70 in counterclockwise direction also one-half pitch, said rotation being transferred to numeral wheel 182 which will be turned through one-half pitch in counter-clockwise direction, that is to say in the proper direction. The remaining one-half pitch rotation of numeral wheel 182 is effected at the end of the return stroke of the operating handle 18, when wheel 1'70 is locked and wheel 1'70 is movable and cross shaft 264 is moved by arm 270 into its extreme left positionin slot 268, because arm 186 has, as above stated, been brought into engagement with cross bar 190, when it was turned one-half pitch in clockwise direction during the forward stroke of the handle,'so that, when arm 2'70 strikes shaft 264, stop 282 will be brought back into engagement with bearing surface 278, and during the final one-half pitch rotation of holder 1'72, until it is locked by cross bar 228, locked wheel 1'70 is standing still, while through the intermediary of holder 1'72 and wheels 1'74, 176, the free wheel 170 is turned the final one-half pitch movement which is transferred to numeral wheel 182, so that this is turned the remaining one half pitch. For those units in which a tens transfer takes place arm 186 will, consequently, after the initial one-half pitch has been transferred to numeral wheel, bear against cross bar 190, and

the movement of arm 184 from the starting position to the first row of selector tongues and back from said row to the starting position will be positively transferredto numeral wheel 182, whereas for all those units in which no tens transfer takes place said movement of arm 184 stroke of the operating handle, still a distance;

in front of cross bar 190 corresponding to onehalf pitch.

As seen tens transfer pawl 266 is returned into normal position first at the end of the return stroke, so that pin 288 or 290 of the gear wheel 1'70, 1'70 released during said return stroke can freely pass above lug 286.

A calculating operation will now be'e-xplained by way of an example. Starting from the initial position as illustrated in Fig. 10, the value 3" is to be entered in additive direction, and supposing that in this case during the forward stroke of the handle 18 pin 196 is in engagement with wheel 1'70, the initial one-half pitch movement brings the shaft 264 into its extreme right hand position in slot 268, all arms 186 one-half pitch distance away from cross bar 190 and all arms 184 immediately in front of the first selector tongues 64, all wheels of the differential gear not having been moved relatively to each other. On the continued rotation of holder 172 in counter-clockwise direction wheel 1'70 is stationary, while wheel 1'78 through the intermediary of the differential wheels 1'74 and 176 is moved three pitches in counter-clockwise direction, in which position the arm 184 is bearing against the selector tongue 64, representing the value 3. On the return stroke of holder 1'72 pin 198 engages wheel 170 so that this wheel is stationary, while wheel 170 is turned three pitches in clockwise direction. The pin 290 on wheel 1'70 is now standing three pitches to the right of lug 286 and the pin 288 on the wheel 1'70 is standing three pitches to the left of the lug 286. The numeral plate. 180 has been rotated three steps'in additive direction. Supposing now that the value 8 is to be added. During the forward stroke of holder 1'72 wheel l'lO will be moved as before .in counterclockwise direction eight pitches. When the pin 290' on the wheel 170 reaches the lug 286, that is between the sixth and seventh step of wheel 170 pawl 266 is pressed down, so that stop 282 on arm 186 is drawn by spring 284 against shoulder 280 in the recess 276 of the pawl 266, which results in arm 186 moving one-half pitch in clockwise direction, the pin 196 carrying forward the wheel 1'70 of the next higher order also one-half pitch in clockwise direction, with the result that the numeral plate 180'in the 'correspondingunit will be moved one-half pitch in counter-clockwise direction, that is in the proper direction. During the return stroke of holder 1'72 pin 288' on wheel 1'70 will pass over lug 286,

..in clockwise direction relatively to wheel 170,

now locked, and therefore the numeral plate will be turned the remaining one-half pitch in counter-clockwise direction.

The quotient register The quotient register which also may be termed the handle stroke counter denotes in addition and subtraction the number of items, while in division it develops the quotient and in multiplication the multiplier, as the operations proceed. This register is disposed to the right of and transversely in line with the total register and in front of the selector. In the embodiment shown this register is "constructed as follows (see Figs. 21 to 24 inclusive).

Fixed between the right side frame 42 and the partition Wall 72 are two plates 300 and 302 between which the quotient register is arranged. Placed between said plates 300 and 302 are a plurality of partition plates 304 and one unit of the quotient register is arranged in each of the spaces thus formed. The quotient register units comprise each a numeral wheel 306 with a numeral disk 308 attached thereto, a gear wheel 310 meshing with said numeral wheel 306, two pawls 312 and 313, a double armed lever 314 in which said pawls are journalled and a tens transfer pawl 316. The numeral wheels 306 are loosely journalled on a shaft 318 secured to the partition wall '72 and the side frame 42, and the gear wheels 310 are mounted in similar manner on another shaft 320 also fixed to said wall and frame. Pawls 312 and 313 are each rockably mounted on a stud 322 and 324, respectively, secured to corresponding partition plate 304, said studs being placed on each side of the center of rotation of lever 314. Lever 314 is journalled on a shaft 326 secured to side frame 42 and partition wall '72, and one arm thereof is connected with corresponding partition plate 304 by a spring 328, whereas its other arm is shaped as a claw. .One lip 330 of the claw forms a bearing surface for a cross bar 349 to be described in the following, whereas the other lip 332 is provided with a stop 334 normally co-operating with abearing surface 336 on tens transfer pawl 316. The latter is rockably mounted on a shaft 338 secured to partition wall '72 and side frame 42 and has besides the bearing surface 336 another bearing surface 340 co-operating with stop 334 in another position of pawl 316, as well as a recess provided with a bearing surface 342 and a cut-out 344 for the purpose described in the following. Further tens transfer pawl 316 is rigidly connected with an arm 345 carrying a tooth adapted to co-operate with a cog 347 on the gear wheel 310 of the next lower denomination unit. Pawls 312 and 313 are each actuated by a spring 346 and 348, respectively, fixed to corresponding lever 314.

The quotient register is controlled by a bell crank lever 350, 352 journalled on shaft 326, a link 356 rockably mounted on a stud 358, a bridge 360 at each side of the register swingably mounted on a cross shaft 358 fixed in frame 42 and wall 72, said bridges 360 being connected by a cross bar 3'72, and another bridge 362 at each side of the register journalled on shaft 338, said latter bridges being connected with each other by means of a cross bar 364. Link 356 is pivotally connected with bridge 360 by means of a link 366 pivotally secured to bridge 360 at 368 and to link 356 at 370. Pawl 312 is adapted to co-operate with numeral wheel 306 and is bifurcated at its end. Projecting through the opening of the fork is the cross bar 3'72 which is common to all pawls 312. The pawl 313 is adapted to co-operate with the gear wheel 310 and is U-shaped at its lower end. Projecting through the opening of the U is a cross bar 3'74 common to all pawls 313 and secured to link 356. One arm 352 of lever 350,352 is by means of a link 3'76 connected to bridge 362, said link being at its upper end provided with an elongated slot 378 in engagement with a pin 380 on bridge 362. Further, lever arm 352 is connected with said bridge by means of a spring 382 and at its end provided with a cross bar 349 engaging the bearing surface 332 of lever 314.

The quotient register is controlled decimally by the selector by following means:

Swingably mounted in the machine frame (see especially Figs. '7 and 21) at 382 and 384, respectively, on each side of the calculating mechanism are two links 386, 388 and pivoted to said links at 390 and 392, respectively, is a rod 394 provided with an elongated slot 396 in engagement with a pin 398 on another rod 400 extending along the quotient register and provided at its right hand end with an extension forming a die 404. Extending along the rod 400 is a toothed bar or rack 406 arranged in such manner that pin 398 engages a toothed space in said rack, whenrod 394 is raised in a manner to be described in the following. Rack 406 is rigidly connected with the selector carriages in any suitable manner and provided at its left end with a downwardly projecting stop 402.

In the starting position of the selector die 404 lies in the first unit to the right of the quotient register in which it engages the cut-out 344 in tens transfer pawl 316. When the selector is advanced step by step to the left on setting up a number in same, die 404 remains in said unit of the register. When, however, in the manner described below, the rod 394 is raised by means of the parallel movement means formed by links 386 and 388, pin 398 engages a tooth space in rack 406 causing rod 400 t be locked to the selector carriage, so that, co sequently, said rod 400 takes part in the step-by-step movement of said carriage, the pin 398 sliding in slot 396 in rod 394. Stop 402 of rack 406 serves to restore rod 400 into starting position, when rod 394 assumes its lowered position.

Lever arm 350 and link 356 co-operate with a controlling device on main driving shaft 162 of the same type as that of the calculating mechanism (see especially Figs. 15 to 20 inclusive). As

these devices are identical it is thought to be unnecessary to describe both in detail. It should be observed, however, that in the controlling device of the calculating mechanism pawls 238 and 240 correspond here to pawls 408 and 410, cam disk 248 to cam disk 412, arm 254 to arm 414, link 256 to link 416, ratchet disk 258 to ratchet disk 418 and cam disk 260 to cam disk 420. Secured to main driving shaft 162 is further a cam disk 422 shown in Fig. 20 and having only one cam which in the starting position of the machine engages lever arm 350 which latter is pressed against the cam by means of a spring 426 fixed to the machine frame at 424. Link 356 carries a roller 428 engaging cam disk 420 against which the link is pressed by a spring 432 secured to the machine frame at 430.

The quotient register operates in the following manner, it being assumed that the die 404 lies in the unit of the register which is shown in the drawings. On the forward stroke of the operating handle arm 350 is turned in counter-clockwise direction, so that arm 352 is lifted. All levers 314 in the different units which have before been locked by cross bar 349 are thereby permitted to turn in counter-clockwise direction under the action of springs 328. All these levers are, however, also locked by stop 334 on the levers 314 abutting against bearing surface 336 of tens transfer pawl 316. In the unit of the register containing die 404 lever arm 352 can swing upwardly, as tens transfer pawl'316 is swung in (ill counter-clockwise direction, said pawl being by die 404 locked to cross bar 364 and, thus, to bridge 362 which takes part in 'thisswinging movement about shaft 338, until stop 334 instead of bearing surface 336 engages bearing surface 340. This small swinging movement is permitted by the deflection of rod 400, as said rod is journalled only by pin 398 and die 404 is placed at the other end of said rod. In all other units the upward swinging of lever arm 352 only causes a swinging of bridge 362, as there is nothing that prevents cross bar 364 from swinging, pin 380 of bridge 362 thereby sliding in slot 378 of link 3'76 tensioning spring 382. The tens transfer pawl 316 remains unactuated and lever 314 can not move on account of the engagement of stop 334 by bearing surface 336.

On the contrary in the unit containing die 404 the swinging movement of lever 350, 352 causes a swinging of lever 314, until, as stated above, stop 334 engages bearing surface 340s Thereby pawl 312 is moved downwardly through a certain distance causing numeral wheel 306 to be turned in counter-clockwise direction. the arrangement being such that this rotation of the numeral wheel 306 corresponds to half a pitch. As described above in connection with the description of the controlling device of the calculating mechanism, cam disk 420 controlling link 356 is not actuated on the forward stroke of the operating handle,

when the machine is set foraddition or multipli cation as is the case in the position shown in Fig. 22, such rotation, however, taking place on the return stroke of the handle, link 356 thereby swinging in counter-clockwise direction. This swinging of link 356 causes first disengagement of pawl 312 with numeral wheel 306, as by the connection of link 356 with bridge 360 by means of connecting link 366 said bridge is swung in clockwise direction, rod 372 pressing pawl 312 out of engagement with numeral wheel 306., At the same time pawl 313 is forced into engagement with gear wheel 310 on account of the engagement of said pawl with link 356 by means'of cross bar 374, causing the gear wheel 310 to be moved through an angle in clockwise direction corresponding to half a pitch, said rotation being transferred to numeral wheel 306 which is, consequently, turned through a corresponding angle in the same direction as before, that is to say counter-clockwise. direction. Consequently, numeral wheel 306 has been turned through one step in all. When roller 428 engages the next recess in cam disk 420 and lever arm 350 rides up on earn 422, pawls 312 and 313 are restored to normal, cross bar 349 pressinglever 314 back, returning stop 334 into engagement with bearing surface 336 of tens transfer pawl 316 which in turn is swung in corresponding direction by means, of bridge 362 and spring 382. Now all parts are restored into starting position.

If canrdisk 412 is shifted by means of link 416 numeral wheel 306 is on actuation of the handle rotated in opposite direction, thefirst half step being effected by pawl 313 engaging gear wheel 310 during the forward stroke of the operating handle and the second half step by pawl 312 engaging. numeral wheel 366 during the return stroke of the handle.

It is evident that by moving die 404 into another unit of the register the registration maybe exccuted in any denomination, this being of importancein multiplication and division.

As said above tens transfer pawl 316 is provided with an mm 345 having a tooth co-operat The control keys The character of operation of the calculating mechanism is determined by a plurality of control or shift keys.-

In subtraction the caluculating mechanism should evidently subtract and also the quotient register. For this reason the subtraction key Ieve'r 440 must be connected with the link 256 of the controlling device of the calculating mechanism as well as with the link 416 of the corresponding device of the quotient register. In division the calculating mechanism should subtract, whereas the quotient register should add, and consequently, the division key lever 442 is only connected with the first of said levers 256. In order to prevent depression of one ofthe subtraction or division keys 22 and 26 on operation of the other the following means are provided. The subtraction key lever 440 is rigidly connected with the link 416 by means of a bolt 444 (see Figs. 15 and 22) At the end of the division key lever 442 is a longitudinal slot 446 in engagement with a pin 448 fixed to link 256 (see especially Fig. 5) Further said link 256 is at its lower end provided with a. bent portion 450 catching under the subtraction key lever 440. Thus, on depression of the subtraction key 22 link 416 is lowered and by means of bent portion 450 also link 256. but the division key 26 maintains its raised position, pin 448 slid ing in slot 446 in said key, whereas on depression of the division key 26 only link 256 is lowered.

In division and multiplication the number A up in the selector must evidently remain therein on actuation of the operating handle, and, con-' sequently, the selector carriage must remain standing in its leftward advanced position. no matter how many times the handle 18 is actuated, in order to repeatedly introduce the same item in the calculation. To this end the following means are provided.

The division key lever 442 is rigidly connected with an ascending link 452 see especially Fig. 7 1 provided at its upper end with an elongated slot 454 in which engages a pin 456 at the free end of a lever 458 pivotally journalled ina bracket 460 secured to partition wall 72'. Journalled on the same shaft and rigidly connected with said lever 458 is an arm 462 carrying at its free end a. pin '464 adapted to co-operate with stop 146 at the end of lever 142 of the selector zeroizing means above referred to. On depression of the division key 26 said lever 142 is swung in counter-clockwise direction in Fig. 7 against the action of spring 144 causing shoulder 150 to be permanently brought out of contact with stop 140 of hell crank lever 128, 129, independent of pin 148 on link .30. Consequently, on moving the handle, lever 128, 129 will never be locked but can swing freely in and fro so that the selector carriage remains in its advanced position and is not returned home.

In multiplication this operation is effected in the following manner. The multiplication key lever 466 (see especially Fig. 7) is journalled in any suitable manner intermediate its ends about a stud 468 and is at its rear end rigidly connected with an ascending link 470 provided at its upper end with an elongated slot 4'72 in engagement with stud 390 on rod 394 of the quotient register tabulating means above referred to. Pivotally mounted on stud 384' and rigidly connected with link 388 is an arm 4'74 pivotally connected at its free end with a link 4'76 engaging at 478 lever 458 above referred to. On depression of the multiplication key 24 rod 394 is lifted causing arm 462 to be swung in counter-clockwise direction by means of arm 4'74, link 476 and lever 458, thereby bringing bell crank lever 128, 129 permanently out of contact with lever 142 as above described.

On account of the slots in links 452 and 4'70 a depression of one of the multiplication and division keys 24 and 26 has no influence on the other.

In order that in multiplication and division a shifting of the selector shall be followed by a corresponding shifting of the quotient register die 404 controlling the decimal setting of said register is locked to the selector carriage by being brought into engagement with rack 406 on raising rod 394 on depression of the multiplication key 24 or the division key 26.

When the total register is to be cleared the tens transfer means must evidently be set out of function. This is effected on depressing the zeroizing key 32 by the following means. The zeroizing key lever 480 is at its rear end at 482 pivotally connected with a link 484 (see Figure 5) which in turn is at 486 pivotally connected with a bell crank lever488 pivoted on the machine frame as at 490. The latter is at its other end connected with a cross bar 492 extending transversely of the machine and adapted to co-operate with a bearing. surface 494 on all tens transfer pawls 266. On depression of the zeroizing key 32 cross bar 492 will evidently engage tens transfer pawls 266 and lock same so that on actuation of the handle gear wheels 1'70, 1'10 will be stopped by the pins 288 or 290 of said wheels striking the shoulder 286' on the pawls 266 causing numeral wheels 182 of the total register to be zeroized.

The backspace key lever 496 (see Figure 6) is at 498 pivotally connected with a bell crank lever 500 rockably journalled in the machine frame at 502. At its other end said lever engages one end of link 86 carrying pawl 88 of the selector escapement mechanism above referred to. Formed in said link 86 is an elongated slot 504 in engagement with a pin 506 formed on a suitable bracket 508 secured to the partition wall '72 (see especially Fig. 6). On depression of the back space key 30, the toggle lever formed by link 86 and bell crank lever 500 is stretched out causing pawl 88 to be brought into and pawl 108 out of engagement with rack- 84 which is moved to the right a distance corresponding to little more than one pitch of the rack. On the following release of the key by the finger, pawl 108 engages the next tooth space of rack 84 and locks the selector carriage in a position one step further to the right.

The modified embodiment of the calculating mechanism shown in Fig. 26 differs fromthat shown in Figs. 3 to 25 inclusive in the following respects.

The tens transfer pawl 266 and the shifting pawl 194 are arranged in reversed position to that in the previous embodiment.

provided in its outer upper peripheral part with an opening 522 and at its lower peripheral end with a stop 524 resting normally against a cross bar 526 secured to the machine frame transversely of the machine. The bridge 226 is also provided with an opening 528 in line with the opening 522. Projecting through said openings 522 and 528 is a bar 530 slidably mounted in a curved slot 632 in a guiding member 534 on each side of the machine. The stop 188 of the arm 186 bears against the bar 530. The size of the opening 522 is so adapted that the movement of the bar 530 in this opening in the peripheral direction of the wheels 1'70, 1'10 corresponds to half a pitch. The guiding members 534 are each rockably mounted on the side plate and the partition wall 42, respectively, by means of two links 536 and 538 and provided with a lug 540 connected with a link 544 having a roller 546. Link 544 and roller 546 correspond to link 206 and roller 208 in the former embodiment.

Further a stop bar 542 is provided against which the holders 1'72 rest in normal position of the machine.

The controlling device of the mechanism is the same as in the previous embodiment.

The operation is as follows. On the forward stroke of the operating handle the bridge 226 is turned in counter-clockwise direction carrying with it by means of one of the pins 196 or 198 wheels 170, 170 arm 520 with tens transfer pawl 266, arm 186 with shifting pawl 194 as well as holder 1'72 with differential wheels 1'74, 1'76 and numeral wheel 182. Nothing occurs, until arm 184 of the holder strikes a projected tongue 64 1 0 in the selector. Then the first part of a calculating operation begins. The movement of holder 1'72 with the differential gearing ceases, whereas bridge 226 with tens transfer pawl 266 and as well as arm 186 with shifting pawl 194 continue their rotation. As one of wheels 1'70, 1'70 is locked by shifting pawl 194, the differential wheel 1'74 or 176 in mesh with said wheel rolls on the locked wheel, causing numeral wheel 182 to be turned through an angle corresponding tohalf the number of teeth represented by the key depressed. During the return stroke of the machine, the other wheel 1'70 or 1'70 is locked by shifting pawl 194 so that the numeral wheel 182 is rotated in the same direction as before as de- 5 scribed with reference to the previous embodiment. The rotation ceases, when bar 228 strikes arm 184, whereafter the holder 226 takes part in the rotation and, consequently, no rotation is transferred .to numeral wheel 182. During the return stroke, said wheel 182 has, thus, been rotated through the second half of the number of teeth represented by the actuated tongue. All the arms 184 are returned to normal by bar 228 in which position they bear against rod stop bar 542.

The tens transfer takes place in the same manner as in the former embodiment, it being observed, however, that the opening 522 in arm 520 can be said to correspond to the elongated slot 268 in the side plates 40, 42 in the former embodiment. i

It is clear from the preceding description that the principle on which the invention is based can be utilized in a plurality of ways. The differential gearing formed in the first embodiment of the wheels 13, 15, 21 and 23 and in the second and third embodiments of the wheels 1'70, 1'70,

174 and 176 may be replaced by a differential gearing in which the two main calculating members consist of twojbevel gears meshing with

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