US2289056A - Computing machine - Google Patents

Description

y 1942- w. w. LANDSIEDEL 56 COMPUTING MACHINE Original Filed Feb. 5, 1934 7 Sheets-Sheet l INVENTOR WALTER W. LANDSIEDEL.

ATTO R HEY y 1942- w. w. LANDSIEDEL 2,289,056

COMPUTING MACHINE Original Filed Feb. 5, 1934 7 Sheets-Sheet 2 INVENTOR WALTER W. LANDSIEDEL ATTOR NEY July 7, 1942. w. w. LANDSIEDEL COMPUTING MACHINE '7 Sheets-Sheet 3 Original Filed Feb. 3, 1934 INVENTOR WALTER W. LANDSIEDEL ATTORNEY July 7, 1942. w. WILANDSIEDEL COMPUTING MACHINE Original Filed Feb. 3, 1954 7 Sheets-Sheet 4 00m hwm lNVENTOR WALTER W. LAN D SIEDEL ATTORNEY July 7, 1942. w. w. LANDSIEDEL COMPUTING MACHINE Original Filed Feb. 3, 1934 '7 Sheets-Sheet 5 INVENTOR WALTER w. LANDSIEDEL Y E N R O T T A July 7, 1942. w, w. LANDSIEDEL COMPUTING MACHINE Original Filed Feb. 5, 1954 '7 SheetsSheet 6 INVENTOR WALTER W. LAN DSIEDEL ATTORNEY July 7, 1942. w. w. LANDSIEDEL.

COMPUTING MACHINE 7 Sheets-Sheet 7 Original Filed Feb. 5, 1934 INVENTOR WA LTER W. LAN DSIEDEL n it mom OQM m um owm mmm ATTORN EY Patented July 7, 1942 I 2,289,056 COMPUTING MACHINE Walter w. Landsledel, Elmira, N. Y., asslgnor to Remington Rand Inc., Buflalo, N. Y., a corporation of Delaware Original application February 3, 1934, Serial No.

Divided and this application October 27, 1939, Serial No. 301,560

Claims. ((1235 60) Letters Patent filed February 3, 1934, S. N.

709,604, now Patent No. 2,203,533, dated June 4, 1940 which parent patent discloses a complete adding, subtracting and recording machine. The present application relates more especially to the means for efiecting and controlling the engagement of the register with and its disengagement from its actuating racks to bring about various operations such as adding, subtracting, non-add, and total taking. To provide new and improved means for that purpose, is the principle object of the invention.

In the accompanying drawings,

Fig. 1 is a right-hand side elevation of an adding and subtracting machine having the invention embodied therein; I

Fig. 2 is a right-hand side elevation of some of the mechanism with the total key set for taking a total but with the mechanism otherwise normal;

Fig. 3 shows the same setting as Fig. 1 but with the parts as they stand in the course of the return stroke of the operating mechanism;

Fig. 4 is a vertical section on the line 4-4 of Fig. 3 and looking toward the front of the machine as indicated by the arrows;

Fig. 5 is a right-hand side elevation of a portion of the mechanism with the total key set for taking a sub-total and the mechanism otherwise at normal; 9

Fig. 6 is a detached view of the subtraction key and some of the mechanism controlled therey;

Figs. 7 and 8 are right-hand side elevations illustrating the non-add key and its associated parts, said key being in normal position in Fig. 7 and depressed in Fig. 8;

Figs. 9-12 are detached diagrammatic views of the mechanism concerned in shifting the register into and out of mesh with its actuating racks. In Fig. 9 the parts are in normal position; in Fig. 10 the parts are in the position for taking a total with clearing but before the operating mechanism has started; in Fig. 11 the parts are shown atthe end of the forward stroke of a computing The mechanism shown in the drawings is a portion of a complete printing adding and subtracting machine fully described in the parent case, now Patent No. 2,203,533, but the present invention may be embodied in machines of other design and it may itself be modified in its details of construction. Thesaid machine comprises a series of differentially settable type carriers I01 (Fig. 8, for example) each carrying numeral types I08 adapted to print against a platen IIII. These type carriers are reciprocated after the general fashion of such machine by a drive shaft II5 which may be oscillated forward and back by the usual handle or motor, and they are arrested in computing cycles by key-set stop mechanism not shown. Each bar I01 has a U-shaped rack bar I II mounted thereon by the usual pinand-slot connections 290, NE, and spring 292 to actuate the register wheels IIZ both for accumulating and for carrying the tens.

Said register wheels stand between opposed racks, the teeth of which are cut in the proximate edges of the branches of the bars III, the wheels being engaged with the forward racks for addition and with the rear racks for subtraction. The register wheel shaft is mounted in a register frame I51 which is slidably mounted at its forward part and which at its rear part is mounted on two arms I64 fast on a rock shaft I65, by the rocking of which shaft the frame may be moved forward for .addition or rearward for subtraction from a middle position where the wheels are out of mesh with the racks. The movement of the frame is limited by shoulders I13 and I14 striking a fixed cross bar I10.

The mechanism formoving the register wheels into and out of mesh with the racks, that is to say, the mechanism for rocking the shaft I65, comprises a main shifting plate 343 slidably mounted on the main frame of the machine at the right hand side thereof. The outline of this plate can be traced in Fig. 9 where it will be seen that it has a wide portion back of the main shaft H5, and a narrower portion projecting forwardly beneath said shaft. It is supported and guided for horizontal sliding motion by two grooved rollers 344 and 345 journaled on posts 346 and 341 projecting a suitable distance from the n'ght-hand'side plate of the machine, said rollers engaging in slots in the plate. This plate 343 is shiftable to two positions, viz., a forward normal position shown in most of the drawings,

the roller 342 passes.

356 pivoted on a post 3!, said roller engaging in two V-shaped notches 352 in the plate.

The plate 343 has a cam slot or opening 353 into which projects a follower roller 342, mounted on an arm 341 fast on the shaft I65. The rear portion of this opening is of such width up and down, that the roller 342 can occupy in it a lower position shown in full lines in Fig;9and in which the register wheels will engage the forward or adding racks, as shown in Fig. 2, or an upper position, shown in Fig. 9 by broken lines, in which the register wheels engage the rear or subtraction racks. The opening 353 has its forward portion of a width substantially equal to the diameter of the roller 342, and disposed at a middle level, so that, whenever the plate 343 is in its rear position shown in Fig. 11, the roller 342 is forced to its middle position in which the register wheels are positioned mid-way between the opposed racks and not in engagement with either. Y

The movement of the roller 342 from its neutral position, shown in Fig. 11, to its add or subtract position, as the case may be, is controlled by a switch cam 354 pivoted to the plate'343 on a stud 355 about whichit can rock to an extent limited by two stop pins 356. This switch consists of a plate lying against the outer face of the plate 343 and having an opening through which Projecting forward from the rear edge of this opening is a pointed cam finger 351. This finger and the opening 353 in the plate 343 are so designed that, when the switch 354 stands in its upper position shown in Fig. 5, the lower edge of the finger and the lower edge of the opening 353 define a cam slot extending first at a downward inclination fromswitch can be swung either up for addition or. down for substraction, and then, when the plate Q 343 is moved forward, the roller 342 will be cammed down or up as the case may be,

It will be perceived that, whenever the plate 343 is in its rear position, the register wheels are out of mesh with the racks, and, whenever said plate is in its forward position, the wheels are in mesh with either the add or subtract racks, depending on the setting of the switch 354. Various means may be provided for shifting the plate 343 and these may be controlled in a variety of ways to produce desired operations of the machine. In the present instance the means for shifting the plate comprise three pins or studs projecting rightward from cam plates 365 and 366, which are fast on the main shaft H5, viz. a comparatively short pin 366 and two longer pins 36I and 362. Their operation is' illustrated diagrammatically in Figs. 9-12. Figs. 9 and 10 show the main shaft in normalposition and Figs.

11 and 12 in its extreme operated position (end of forward stroke). The plate 343 has an ear or lug 363 so disposed that in normal position it stands just in front of the pin 36!. The construction is such that, when the main shaft makes its return stroke from the position shown in Fig. 12 to that of Fig. 16, the pin 36l will, in the very last part of such return stroke, strike this lug 363 and force the plate 343 back to its active position. It will be perceived, therefore,

that in the specific machine described, when the main shaft l I 5 is in normal position, the register wheels are always in engagement.

It will be noted in Fig. 11 that the pin 366 has passed to the rear of the front edge of the lug 363. This is the short pin, and said lug is offset to the right so as not to stand in its path, but so as to be operated by the long pin 36!.

In Figs. 9 and ll the mechanism isshown set for computing operations (addition or subtraction). In these pperations the plate 343 is shifted rearward to move the register wheels out of mesh at the first part of the forward stroke of the main shaft, and forward to throw them into mesh at the first part of the return stroke. The first of these movements is effected by the pin 36! acting on a dog 364 and the second by the pin 366 acting on a dog 365, both dogs pivoted to the shifting plate 343 on a stud 363. The dog 364 is on the outer face of the plate 343 and its end normally stands just back of the 'pin 36! in about the same plane as the lug 363. This dog can be depressed to the position shown in Fig. 10, where it is out of the path of pin 3M and, therefore, inactive. It is drawn upward by a spring 366 until arrested in normal active position by a stop pin 361. In an adding or subtracting operation, in the first part of the forward stroke of the main shaft, the pin 36!, acting on the end of dog 364, pushes the plate 343 to its neutral position, shown in Fig. l and the end of the dog then passes out of the circular path of the pin, which moves on free of the dog. The dog 365 is mounted on the inner face of I the plate 343, and its forward end is formed into a hook 366, having an abrupt rear edge, and an inclined forward edge,',and in a plane where it can be reached by the short pin 366. In the last part of the forward stroke of the main shaft saidpin 366 strikes the inclined edge of the hook 366,

depressing it momentarily and then escapes beyond it, as shown in Fig, 11. In the first part of the return stroke, the pin 366 engages the abrupt rear face of hook 366 and draws the plate 343 forward to its active position, the hook 368 then passing out of the path of the pin. The dog 365 is drawn upward by a spring 316 against a stop pin 3 (Fig. 11). At its forward end it is guided by a grooved stud, projecting from the 4 plate343, so as to space it properly from said plate, said stud lying in a slot in the dog.

In total taking operations use is made of a third dog 313, pivoted at 314 to the upper part of the plate 343, and extending forward from said pivot. This dog is urged downward by the spring 366 to the position shown in Fig. 10, where it is arrested by a stop pin 315, and where its free end is in the path of motion of the pin 362. In computing operations this dog is held in its upper position, shown in Figs. 9 and 11, where it is out of the path of said pin.

In Figs. 10 and 12 the dogs are shown set in position to take a total (with clearing). The dog 313 has been allowed to drop down to its operative position and the dogs 364 and 365 have been depressed to inoperative position out of the paths of the pins 36! and 366. Since the roller 342 is in its upper position in these figures, the machine is set for taking a negative total, the register wheels being initially in mesh with the subtracting racks H4. Since the dog 364 is out of the path of the pin 36!, when the main shaft is rocked to the position, shown in Fig. 12, the shifting plate 343 will remain in its active position and the register wheels will, therefore, re-

main in mesh with the racks during the upward motion of the .latter. During this motion the pin 362 snaps under the dog 313, which drops down behind it, as shown inFig. 12. In the first part of the return stroke, therefore, this pin.

acting on the dog :13, will push the shifting I to normal position. It will be perceived that in plate to its rearor neutral position, leaving the register wheels out of mesh with the racks duf ing the'return stroke of the latter. At the end of the return motion, the pin '36I engaging. the lug 363 will draw the plate 343 back to its active position. As will appear hereinafter, the switch 354 will m'eanwhilehave snapped back to its adding position so that, when the wheels are vent the dogs from following the pins so that the latter escape from the ends of the dogs and proceed on their way.

In the total taking operation, just above de--,' scribed, if the dog 365 had been in its upper activeposition, the pin 366, engaging it earlyin the return stroke of the main shaft, would have 9,

endeavored to draw the plate 343 forward in, opposition to the pin 362. It is therefore necessary that this dog 365 be in its depressed position during this operation.

The cooperating mechanism, involved in this total taking operation, is shown in Fig. 2 in the,

position it occupies, after the total key has been set, and before the main shaft has been rocked,

but in this figure the machine indicates a positive total.

In Fig. 3 the parts are shown set for a total taking operation, and in the position they occupy early in the return stroke of the main shaft H5. Here the pin 362 has a little more than half completed the pushing of the dog 313 and plate 343 back to their neutral position. By the time the plate is entirely back, the pin in its circular motion will pass off of the end of the dog, leaving the register wheels out of mesh for the return stroke of the racks.

In order to take a sub-total, the dogs 364, 365 and 313 are all three set in inoperative position as shown in Fig. 5, with the result that, when 1 the main shaft is rocked, the shifting plate 343 remains in its normal active position throughout the entire cycle, the register wheels remain- I operative or in its inoperative position. As the plate v343 is already inits active position this dog would be inoperative even if it stood in its normal upper position.

In Fig. 8 the dogs are shown set for a nonadd operation. In this figure the main shaft H5 has'been rocked forward and most of the way back. The only change from normal setting for this operation is to, depress the dog 365 to inoperative position. The dog 364, being in normal position the plate 343 was pushed back to neu-' tral position at the first'part of the forward stroke of the shaft. Since the restoring dog 365 was depressed to inactive position the plate remained in that position during the return stroke of the shaft up to nearly the end thereof. In

grasped f 1 3 Fig.8the pin :61 is shown only senor: distance from its home position, and in the act of engaging the lug 363 and drawing the plate 343 back to its normal active position. This takes place at the extreme endof the return stroke and after the type bars and'racks have all'been restored this operation the register wheels were out of mesh with the racks during both the forward and return strokes of the latterrand that therefore, a number set up on the stop carriage was printed,

, but not added.

The conditions for the various operations are therefore as follows: Adding or subtracting, dogs 364 and 365 active, dog 313 inactive. Total (with clearing) dogs-364 and 366 inactive, dog- 313 active. Su -total,-dogs 364 and 313 inactive. Non-add, dog 364 active, dog 365 inactive.

Total and sub-total mechanism The total and sub-total key I24 consists of a" lever pivoted at the right of the keyboard on a I stud or post 330 projecting rightward from the right-hand side plate of the keyboard section of the machine. When this lever occupies the normal middle position, shown in Fig. l, the machine is not set'for' total taking. when the key is pushed to its rear position, shown in Figs. 2 and 3, it sets the mechanism to take a total with clearing, and, when pulled to its forward position, shown in Fig. 5, it sets the mechanism to take. a sub-total. As shown in the latter 118- ure, there are pivoted on the stud 386 two centering levers 38I, drawn together by a spring 362,

and when so drawn together, as shown in Fig. 1, they pinch between them a stud 383 projecting leftwardirom the lever I24 and also a fixed stud 384. The lever is locked in either set positions by means of a latch lever 385 having an ear 336. bent off therefrom in position to engage either one of two lugs or teeth 381 and 388 projecting from the lower end of the lever I24. The latch lever 385 is controlled by a spring 396. The construction is such that the lever may be moved to either of its two set positions and it will be retained there by the latch lever 385, until at the proper point in the total taking cycle this latch lever is released, whereupon the key will be returned to its middle position by the spring 382. The stud 383 also projects outwardly from the lower arm of the lever I24 and it has pivoted thereon a sliding link 39I, whose shape and mounting are perhaps best shown in Fig. 2. This link extends rearwardly and it has a guide slot 392 by which it is suitably guided on a stud 393, Figs. 2 and 4, projecting rightward from the main frame plate I28 (leftward in Fig. 4, which is a section looking toward the front of the machine). The link 39I has forward of the stud 393 an upwardly projecting finger 394, and to the rear of said stud a downwardly projecting finger 395. Pivoted on the stud 393, Figs. 2, 3, and 4, are an inner bail 396 and an outer bail 391, the former nested within the latter, the link 3!" being between the righthand pivoted arms of thebails. The finger 395 hangs down behind the cross bar of the outer bail 391 so that, when the key I24 is moved to its rear or total taking position, and the link 391 is thereby drawn toward the front of the machine, this finger will rock said bail clockwise, as shown in Figs. 2 and 3. When, however, this key is pulled to its forward sub-total position, as shown in Fig. 5, the upper finger 394 thereof acts on a stud 398 projecting from an upwardly I 7 extending arm of the inner bail 366,. and rocks, said inner bail clockwise, but does not rock the.

outer ball. The outer bail 361 has a rearwardly extending arm 406 to which is pivoted the lower end ofan upright link "401, the upperend o'f which-has a vertical slot by which the link is guided for up and down motion on a post 402 projecting rightward from the frame plate I26.

The inner bail 666 has its right-handarm prolonged rearward into an arm 403 (Fig. 3) to the rear end of whichis pivoted another vertical sliding link 404, having in its upper part a vertical slot 406 by which it is guided on apin 466 projecting inward from the link 40l. This pin normally stands at the bottom of the slot,

so that, when the link 46! is drawn down for.

total-taking, it draws the link 404 down also. The link 404 also has a pin 401 projecting inward therefrom and overlying the two dogs 364 and- 366. The upper pin 406 on the link 40l underlies the upper dog 313. The two balls 366 and 391 are controlled by two springs 406 (Fig. 5), which tend to hold the links 40f and 404 in their upper positions limited, respectively, by

the post 402 and the stud 406. The parts are 25 of the main shaft. In Fig. 8, the parts are shown shown in normal position in Fig: 2, where the upper stud 406 is holding the upper dog 313 in inoperative position, and where the lower stud 4011s out of contact with the dogs 364 and 366, allowing these dogs, therefore, to occupy their operative positions. The mechanism is,

therefore, set for computing operations, the plate 343 being pushed rearward to its neutral position by the dog 364 in the flrst part of the forward stroke of the main shaft and returned to active position by the dog 366 in the flrst part -of the return motion of the shaft as above described.

,When the total key I24 is pushed to its rear position, shown in Fig. 2, both slides 40! and-404 are pulled downward with the result that the pin 406 permits the upper dog 316 to drop operative position and the pin 401 depresses th two dogs 364 and 366 to inoperative position. This is the setting for taking a total, as above described. The register wheels are already in 5 mesh, and on the forward stroke of the main shaft they will remain in mesh because the dog 364 isin inoperative position. During this stroke the pin 362 will deflect the dog 313 which at the end of the stroke will drop in behind it so that, at the first part of the return stroke this pin, acting on said dog,'will restore the shifting plate 343 to its neutral position; the register wheels will then be at zero and will so remain.

when the total key I24. is drawn forward to take a sub-total, as shown in Fig. 5, only the inner bail 396 is rocked, the outer bail 361 res maining in normal position. The inner slide 404, will, therefore, be pulled down, but not the outer slide 40l. .The pin 406 will, therefore, continue to hold the upper dog 313 in its inoperative position, but the lower pin 401 will depress both dogs 364 and 366 to inoperative position. This is the condition for a sub-total, as above described. The register wheels are already in mesh with the racks and theywill remain so throughout the cycle, all of the shifting dogs being inoperative.

The non-add key I22 and its connections are shown in Figs. 7 and 8. As shown in Fig. 8, the stem 426 of this key has a pin 426 projecting leftward therefrom between the branches of the forked end of an arm fixed on the left end of a long rock shaft 421, which (Figs. '7 and 8) has 76 65 viously be imparted to the shaft 70 jecting therefrom through a slot 664 in the shiftmounted thereon a rearwardly extending arm 426. Said arm-423 has a pin'430 projecting rightwardiy therefrom'and overlying a shelf or flange 43l bent leftward from the lower part of the s forward end of the dog 366. The construction is such that, when the key I22 is depressed, the shaft 421 and arm 426 are rocked clockwise in Fig. 8, the pin 430 acting on the flange 43i draws the restoring dog 366 down to its inoperative ition, as shown in Fig. 8. The length of the ange 431 is such that said flange remains beneath the pin "430 during the reciprocations of the dog 366 with the plate 343. The depression of this key. therefore, withdraws the dog366 to 16 inoperative position, leaving the dog 364 in its operative position and 313 in its inoperative position. When, therefore, the main shaft takes its forward stroke, the pin 36L acting on the dog 364, immediately moves the shifting plate 20 343 to its 'rear inactive position, and, since the at this stage of the operation. That is to say the register wheels are out of mesh;but the pin 36i, which has nearly completed its returnexcursion is about-to restore the register wheels to engagement. During this cycle the type bars I01 are free to move upward and the number set up on the stop carriage to be printed, but the register wheels will not be aflected.

Subtraction case, setting the mechanism for subtraction involves not only the shifting of the cam switch 364 from its upper normal'position to its lower 4 position shown in Fig. 10, but also the shifting of certain parts in the register mechanism itself.-

The present invention is concerned only with the switch 364. This is shifted by the operating mechanism'under control, in computing cycles, of a subtraction key l2l and in total taking by other means set automatically when a negative balance is to be printed. The subtraction key l2l (Fig. 6) is at the right-hand side of the keyboard and its stem 640 stands above a stud 646 on theshorter arm 643 of a lever having a long arm 642, said arms loosely pivoted on a transverse shaft 6 and connected together by a bail bar 644, and rocked upward by a spring 646.

' The arm 642 at its rear end has a stud 641 on which rests a prolonged end of a pawl or hook 646 which is influenced by a spring 662 and is pivoted at 660 to an arm 66! fast on a rock shaft 303. This shaft is a part of the operating mechanism of the machine and is swung counterclockwise at the first part of the forward stroke of the main shaft H6, and remains stationary until near the end of the return stroke of said shaft when it is rocked back to its normal position shown in Fig. 6. This movement may oh- 306 by any suitable means. A linkage for the purpose is described in the parent case. The oscillation normally causes the hook 646 to rub back and forth idly on the stud 641. j

The switch 364 has a stud 663 (Fig. 10) pro- -ing plate 343, and a tension spring 666 (Fig. 6) connects-this stud with a stud 666 on an 'arm 661, which is pivoted on a post 668, projecting from the main frame plate I26 and normally In the specific machine described in the parent sets certain parts of the register.

holds the switch 354 in its upper or add position. The arm 551 is part of a pivoted device consisting of two layers connected by a bail bar, said arm lying a little to the left of the shifting plate 343 and the other layer lying adjacent to the side plate I25 and being in the nature of a gear sector 550. The latter meshes with another gear sector constituting a part of another piece pivoted at 552 on a post projecting from the side plate I28. This device is also made in the form of a bail, its outer arm 553 having an car 554 bent oif therefrom and lying beneath the hook 548. This device is drawn counter-clockwise in Fig. 6 by a spring 555 against a stop 555. The construction is such that, when the subtraction key |2l is depressed, the hook 545 drops down until it rests on the car 554. part of the forward stroke of the main shaft, the arm 55| moves rearward, said hook rocks the device 553, I clockwise and the device 555, 551

counter-clockwise. .The parts are shown in Fig. 6 in adding position, with the spring 555, drawing the switch 354 against the upper stop 355; but, when the arm 551 is swung counter-clockwise, the spring pulls downward and tends to swing the switch down against the lower stop 355, as shown in Fig. 10. The switch will swing down as soon as, in the rearward motion of the shifting plate 343, the roller 342 is out of the way. When, in the return stroke of the main shaft, the plate 343 is moved forward to its active position, the roller 342 will enter the upper branch of the switch and move the register wheels into mesh with the subtracting racks.

When in the last part of the return stroke of the main shaft 5, the shaft 355 and hook 545 return to normal position, the spring 555 restores the parts 55l, 553, and 551 to normal, causing the spring 555 to pull upward on the switch 354, which switch will be shifted thereby to its normal upper position when the roller 342 gets out of its way.

In the parent case, at latch 554 is described to hold the subtract key in depressed position, said latch being automatically released at the proper time.

The drawings show'a sliding plate 515 having a settable two armed dog 513, 552 adapted to be acted on by studs 515, 511 on a plate 515, secured to the main shaft 5. Said dog has an arm 58!! connected by a link 5" with the rocking member 55L 553. When said member is when, in the first rocked by the hook 545 as above described, the

said dog is set so that the plate 515 is shifted by the shaft H5 first toward the front and afterward toward the rear of the machine. This plate It and the mechanism controlled by it are not claimed herein but are claimed in another divisional case, S. N. 179,265, filed December 11, 1937.

Fig. 6 shows a second hook 542 pivoted on the same stud 555 as the hook 545 and capable of operating the member 553, 554 and thus setting the machine in subtract condition, the same as the hook 548. An arm 543 of the hook 542 has a stud 544 adapted normally to be intercepted by two sectors 53!! and 549 and thus to raise the hook and prevent it from acting on the ear 564. These sectors are controlled automatically in such a way that on a blank stroke of the main shaft H5 when the register contains a negative balance, they are out of the way of the stud 549 and permit the hook 542 to set the mechanism in subtract condition. This mechanism is also claimed in the said divisional application S. N. 179.265. It forms no part of the.

present invention except in the sense that its constitutes another means besides the subtract key for bringing the subtract mechanism into action.

Various changes may be made in the details of construction and arrangement without departing from the invention.

What I claim as new, and desire to secure by Letters Patent, is:

1. In a computing machine including a register, actuating racks for said register, a device for engaging said register with and disengaging it from said racks, and operating mechanism including a rock shaft having a forward and a return stroke, the combination which includes three dogs for controlling said device, dog-operating studs or devices on said rock shaft one of said dog-operating devices capable of acting on the first said dog in the first part of the forward stroke of said shaft to disengage said register;

one of said dog-operating devices capable of acting on the second of said dogs in the first part of the return stroke of said shaft to engage said register, and one of said devices capable of acting on the third said dog in the first part of the return stroke of said shaft to disengage said register, said first and second dogs being normally active and said third dog normally inactive, a link (454) which when operated causes said third dog to move to active position, a second link (41) which when operated moves said first and second dogs to inactive position, means for operating both links to take a total, and

means for operating said second link (4M) alone to take a sub-total.

2. In a computing machine including a register, actuating racks for said register, a device for engaging said register with and disengaging it from said racks, and operating mechanism including a rock shaft having a forward and a return stroke, the combination which includes three dogs for controlling said device, dog-operating studs or devices on said rock shaft one of said dog-operating devices capable of acting on the first said dog in the first part of the forward stroke of said shaft to disengage said register; one of said dog-operating devices capable of acting on the second of said dogs in the first part of the return stroke of said shaft to engage said register. and one of said devices capable of I acting on the third said dog in the first part of the return stroke of said shaft to disengage said register, said first and second dogs being normally active and said third dog normally inactive, a link (454) which when operated causes said third dog to move to active position, a second link (45!) which when operated moves said first and second dogs to inactive position, a key occupy g a normal middle position, means operated by said key when shifted in one direction for operating both said links to take a total and when shifted in the other direction to operate said second link (40!) alone to take a subtotal.

3. In a computing machine, including an adding and subtracting register, actuating racks therefor, and operating mechanism, the combination which comprises a reciprocatory cam for moving said register and racks into and out of engagement. a switch included in said cam for determining adding and subtracting engagement, a spring for throwing said switch, means said member and shiftable to two positions having two inclined surfaces one of which in one position of said switch cams said follower in one direction for addition and the other of which in the other position of said switch cams said follower in the opposite direction for subtraction.

5. In a computing machine, means for moving an adding and subtracting register into and out of engagement with opposed racks, comprising in combination a cam follower connected with said register, a reciprocatory member comprising means acting when said member is moved in one direction to'cam said follower to a middle position, and a cam switch on said member and shiftable to two positions in one of which, on movement of said member in the other direction, it cams said follower in one direction from such middle position and in the other of which it cams said follower in the opposite direction.

WALTER W. LANDSIEDEL.

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