US1636718A - Control mechanism for calculating machines - Google Patents

Description

1 2 July 9 7 J. H. F. SILVER CONTROL MECHANISM FOR CALCULATING MACHINES May 27. 1925 J. H. F. SILVER CONTROL MECHANISM FOR CALCULATING MACHINES July 26, 1927.

26 192 July 7 J. H; F. SILVER CONTROL MECHANISM FOR CALCULATING MACHINES Filed May 27. 1925 5 Sheot s- Sheet 3 July 1927' J. H. F. SILVER CONTROL MECHANISM FOR CALCULATING MACHINES gvwentoz d. [6/1 Vf/P,

Sheets-Shoot 4 .Filed May 2'7. 1925 July 1927' J. H. F. SILVER CONTROL MECHANISM FOR CALCULATING MACHINES Filed May 27. 1925 5 Sheets-Sheet 5 llilu Patented July 26, 1927.

UNETED STATES JOHN H. F. SILVER, F PHILADELBHIA, PENNSYLVANIA.

CONTROL MECHANISM FOR ALC LATING MA HINES.

Application filed May 27, 1925. Serial No. 33,192.

My invention relates to calculating and adding machines, one of the important objects, briefly stated, residing in a very simple, highly efiective and practicable type or attachment which may be readily placed upon or built into the existin calculating machines of the type general y known as the key'driven comptometer, for the purpose of warning the operator bynot only a visible signal but by means of an audible signal the instant the stroke of any one of the keys has not been completed, as when the key is but partially depressed.

I am aware of the fact that various at tempts have been made to remedy this very serious difficulty in connection with calculating machines in an vefl'ort to assist the operator to continue his calculations without the necessity of cancelling and repeatsoing. a

As it is well known to those familiar with the art, when a mistake is made, as when a key has; not been'fully depressed, the clean ing lever must be pulled forward for resetting all of the keys to zero in that particu lar column. F or this reaspn,"operators of i this type "of machi'n'e have I found it simpler and faster, on'small calculations', to cancel and go over the problem r' ther than to'sto'p and make the necessary correction. I

yVVith my improved attachment, I" have provided means ifor automatically "locking every key in all ofthe columns simultaneously. In this'manner, it will be readily 35 understood theoperator-is prevented from depressing keys 'of'columns other than ,the one injvhich the partial stroke was made, as, for instance, in'the process of multiplying; and, should the-operator fail to hear the audible -signal, he' 'may readily see at a glance, the particular key which was inadvertently partially depressed.

In the drawings:

Figure l'is a side elevation of a calculat-' clearness and illustrating the key in its normal or raised position;

Figure 5 is asimilar view showing the key but partially depressed and locked;

Figure'ti sho s a similar viewbutillustrates the location of the several parts as when the key is fully depressed and ready to be turned to'its initial or normal position:

Figure 7 isfa horizontal; sectional view taken on the line 7-7 of Figure 6; Figure 8- illust rates a viewi'n perspective of one of the key-'sillustrating my improvenient;" f'

igur'e" 9 is a transverse sectional vie taken on the line 9''9 of Figure 4;

, Figure10is' a similar view taken through e Figure 'll is a view' in perspective of the frame work of my improved attachment clearly illnstrating'the' bell'of the actuating niechanisnr'in connection therewith and f Figure l2 'is 'a'v'iewfin perspective 'on 'an enlarged scaleof's'everal of the details 'illustrating them intlieir co acting' positione My invention, in the form or'enibodim'ent "Susan is the fdrawi ngs-aiid'briefly described, "comprises a pairf of "oppositely disposed -'jgilatesj'lQand llfwli'ich may bereadi ly'riv- "usages "at "12 or otherwise secured to the frame ofthfe e istiiijg ma'cliinelifl These plates, T10andll,'aie suitablylbraced-at'ftheir'outer "and: by meanso'f the us'uala't'ubular Iiaernber, 13, with its assoeiated rod and fastening means. j It is w be nnderstood; 'of '-"cours'e,

i that if rnyattacliin'ent is to'be' built into the p 'ma'chine',"the plates,'1( and 11, would merely 'e bontinued rearwardtv from the side plates of'tlie-inachin e; I 4

f" Inasmuch as" calculating machines of this a'rlelwell 'lirldivh'tqthos familial with ithe-fart I 'willfinak no attempt too into detail with the existing or well ln'iown' maother than what is directly associated witl my, improved "attachment" thereto." On

thello'we'r porti'onof'one of thelegsof the operating key; 15,1: rigidl y se cure afpin, 16, "as isjclearly'illustratd in Figures 8, 9 and 10,' which 'isfextended"partially across the slot formed between the two' lower legs of the key, 15." The purpose of theupins, 16, is to engage the1upper curved surface of hook ortions, 17 which may be either formed integrally withithe upper edge of the usual key" fennel lever, 18, or which may be i tt' f't thre'tii iii. any other del 'titl iiiaiiner';

ti l

lVhen the keys are in their normal position, as is shown in Figure 4 of the accompanying drawings, the pins, 16, are free to more downwardly beyond the hook portion, 17, the said keys being, held in their upper position by means of the usual springs indicated as at 19 j The rear end of the key control lever, 18, is, of course, pivotally mounted to the lower end of the bell crank member, 22, as at 23. and the toothed arm, 24:, is likewise mounted to the upper end of the member, 22, as at .25, they being held in their raised position by means of the coil spring, 26, in the usual manner.

A relatively short distance below the pivot, 25, is loosely pivoted by means of a. rivet, 27, or the like, what might be termed a main control piece, 28, whichisprovided in its approximate center with an elongated slot, 29. The upper and lower edges of. the main control piece, 28, are provided with oppositely formed ratchet teeth, 30- and 31, for a purpose to be hereinafter described. A headed screw, 33-, is adapted to pass through the slot, 29. and is secured to the plate, 10, by means of a nut, 34, for the purposeof guiding themain control piece, 28, during the operation of the keys, 15. The extreme rearward end of the main control piece, 28,; is rounded to form a. nose, -3 5 ,,-5and isfl'also provided atitsupper. edge adjacent to thelnose, 35,'with a cut-out portion, 36, to forma tooth. .3

.. To. the lock control lever,- 40, :and preferxa bly near the rear endlthereof, I provide an upwardly extending portion, 41,-,and arear- Wardly extending and relatively narrow warm, w c in es QY 11e --'or ced-. -43 1A i go a ly, t nd g mu ets t g a y ifcrm s t emppe end .o f-jthe arm, 42,; and-provided oir'its upgra! 1y formed with the lock control leverAD. Upper and lower pawls, 48,and t9,:which, for clearness, may beytermedup pawls and down-pawls, are each ,pivotednat tlieir;,-re 1r ends to the rods, and 5 l 'which extend tra v r y s th supp em imm got :myattachment; trymeans oiangnlarly hent l;ugsor ears,'52-and53. As isobvious {from the: drawings, the pawl, 48, is adapted align with andtengage tihe,tootl i,, 30,. of

' the-main control piece,- .28,whereasthepawl,

49, is in alignment with and adapted'for eneagen'ientwith theplower set of, t e-etli, ;3l. The lugs or ears, 52, are provided witha slightly elongated slot or opening, 54, for a purpose to be further described I The rear end-of tlie rlown .-.pawl, 48, is formed with a downwardly extending toe, 55, which is adapted for engagement with the extreme end of the arm, 56, which is,

in turn, bent downwardly forming an arm. 57. The members forming the arms, 56 and 57, are secured to a rod or shaft, 58, which is joui'nl'iled ih tire-plates, l0 and 11, of the suppleumntatframe. The lower extremity of the arm, 57', is slightly extended as at 5 for the purposeoi forming a latch or (log, and is adapted to engage the outwardly extending arm, 60, which is integrally formed with-the pawl, 61. The pawl, 61, is secured to and carried by the transversely extendii'ig rod or shaft, (32, and is provided on its outer end with an upwardly extending and angularly bent arm, 63. A coil spring, 64, is interposed between and connected to :1 depending arm, 57, and the upwardly extending arm, 63, for the purpose of preventing the accidental displacement of the dog, 59, with respect to the arm, 60.

Pivotal-1y mounted upon a rod or shaft, 67, which is supported between the end plates, 10 and 11, is a plurality of pawllifting arms, 68, one for each column-of keys, as is clearly. illustrated in Figure 3 of the accompanying drawings.-;Eaeh of the arms, 68, is providedwith a pair ofdownwardly bent ears orlugs, 69, which form the' pivotal connection between the rod .or shaft, (37. The forward end of the arin, (38-, is bent.downwardly, as .at 70, which-is provided with-a horizontally: disposed and angularlybent ledge: or extension, 71, for the purpose of eontactin =Wil!l1 and lifting the down-pawl, .48, out o ,engagement'with the ratchet teeth,30,gformed upon theupper edge of themamcontrol piece. The rear end, 72,, of thepawl-liftiirgarms issIightly hentdownwardly andjsadapted to be, engaged by the-forward end, 7 .5 of abell-cranl: member; 76,- ,or, which. might be termed, a cancelling-release arms ThebeH-erank lever,

.T6,. is secured tothetransversely extending perextremity with a, rounded nose, 4 5. -,-..lt;;is

tobe, understood, of course, tha-t,,th e arms, 4-2 -and 44,-,are stamped,.,o r'= otherwise: interod or, .-;shaft,.- 77, which is. s'imilarl y 5constructed' andl mounted asiis the shalt, 58.

. The downwardly extending arm,- 1'8, of the lever, T6, is adapted, t0, be engaged by the z upwardly extending .arm, ,63, which lS,- of

course, integrally formd with the an til'ariy bent pawl, til, which, for the sake 9 clearuess, I may term a stop-hook iewer, The pawl, 61, is also in alignment-with the main control piece, -28, that, at a predetermined period, as .willi be Q hereinafter fnrther. de-

scribech'tlrispawlfmay be engaged by the notch or depression, 36. 'lherebeing but one-belherank memberyTG', it is obvious that the remainder of the forwardly extending plates, 75,-. need not be provided with depending arms,78. .r

Again referring to the pawl-lifting arms. (58, it will be noted with particular reference to Figures 3 and 12, that I have provided an outwardly extending and integrally formed lug or projection, 80, which is adapted to engage at certain intervals theledge Int) or reduced portion, 81, formed on the upper end of a vertically extending and relatively narrow arm, 8&3, which is mounted to oscillate upon a. transversely extending rod or shaft, 8 3. This arm, 82-, is provided at its lowermost edge with a substantially horizontal arm, 84. which bent upwardly to provide the arm, 85. The upper end of the arm, 85, is in line with the nose, 35, of the main control piece, 28, and is adapted to be engaged thereby at predetermined intervals for rocking the arm, 82, whereby the lug, 80, will be disengaged from the ledge, 81. I provide a coil spring, 86, which is secured near the lower end of the arm, 82, and its opposite end to the stationary rod, 88, for the purpose of causing the ledge, 81, to bear against the lug, 80.

A spacing rod or bar, 87, is provided with shoulders and reduced portions at their upper and lower ends, which are loosely mounted in suitable openings in the'pawllifting arm, 68, and the lower or up-pawl, 49, so that they will have the same relative movement. A coil spring, 86, is interposed between and connected to the tip-pawl, 49, and the pawl-lifting arm, 68, for the purpose of applyin tension on the shoulders of each end of the spacing member, 87,

whereby the relative movement of thesemembers will be assuredf 7 Again referring to the rounded'nose portion, 45, formed upon the uper' end of the diagonally extending arm, 44, which is adapted to, at all times, support the pawllifting arm, 08, by hearing against the lower side thereof, I accomplish-this continuous contact by means of a coil spring, 90', which connected at one end to the pawl-lifting device and its opposite'end, to the relatively stationary rod or shaft, 51, as 18 clearly lllustrated in Figures 4, 5, and 6. For the purpose of permitting the downpawl, 48, to bear against and engage the teeth, 30, 'of'the main' control piece and to 'yieldingly retain this-pawl in its forward position by reason of the fact that the rod or shaft. 50, is mountedin an elongated'slot,

54,1 provide a relatively short coil spring,

92, and secure it. at one end to the relatively stationary shaft, 67, and its opposite end to the lug, 93, which is preferably bent up" wardly from the rearward end of'the downpawl, 48.

' For the purpose of permitting the usual lock control lever, 40, to oscillate a predetermined distance about the rod or shaft, 95, I--

provide a downwardly extending lug, 96, which is adapted to pass through an opening, 97, suitably formed in that portion ofthe stationary frame. The cut-out portion, 98, formed in one edge of the depending lug, 96, as is illustrated in Figures 4, 5 and 6, will, of course, permit this movement. The lock control lever, 40, is yieldingly held in its normal position, as is shown in Figure 4, by means of the coil spring, 100, which has one end thereof connected to the arm, 42, and its other end secured to the transversely extending stationary rod, 88.

Referring now particularly to Figures 1 and 2, which indicate generally the resetting mechanism in connection with the usual resetting arm, 105, 106 indicates a slidably mounted lever, having a downwardly and off-setportion, 107. A rocking lever, 108, which is pivoted in its approximate center as at 109, is pivoted at its lower end to the off-set portion, 107, and has pivotally mounted to its upper end one end of a link, 110. The opposite end of the link is pivotally connected to the lower end of an os cillating lever, 111, which is, in turn, rigidly lever, 106, and the pawl, 113, The rod, 83,

may be extendedibeyond the outer edge of the plate, 10, for the purpose of limiting the rearward movement of theslidably mounted --lever," 106, supplemental to the slot and bolt,

101- and 102. T Q The automatic release for the purpose of moving -the'- lever, l06',"a predetermined distanc'oi}"sufiiciently' to actuate the cancelling release arn'f, {76; whichwill "raise the downpawl- 34 through the medium of the pawllifting min," as; is; indicatedfgenerally as at 112. A dog dr"pawl, 113,- ispi-votally mount- "fed to the forward end'of the'lev'er, 106, and

is provided 0n"'it"'s up'per end with an angularly disposed'?stop", -11'4, which'is adapted to bear aga in'st 'thehub por'tion 115', common tothis ty eof calculating machines. Formed "intgra ly-"with thearm, 114,"fis a rearwardly extending portion, 116, for 'the purpose of supporting one" end of a coil spring, '117,' whose opposite end is secured to a gelativlystationary arm, 118, which i's'carri'ed by thefo'rward end of the lever, 106i k}transversely-extending pin,'-"119, is secured to therear end'of theshding lever,

"120', and its upper endis flattened for the purpose of '-more readily engaging the toothed portion of thepawl or dog, 113.

When the lever, 120, is moved forwardly through themedium of the hand resetting arin, 105, to which it is, of course,'pivoted, the pin, 110, will pull the dog or pawl, 113, forwardly and continue until the upwardly extending arm, 114, comes in contact with the hub portion, 115, when a continued movement of the lever,-120, will cause the upward movement of the dog. 113, about its pivot, 121. The pawl, 113, will now begin to be moved upwardly and be freed from the pin, 119, and be returned to its normal position as is shown inFigure 1 and as is illustrated in dotted lines in Figure 2 of the accompanying drawings.

The audible signal, which is associated with my improved key-locking mechanism and which is clearly illustrated in Figure 11 of the accompanying drawings, together with the diagrammatic illustrations shown in Figures 4, and 6, consists of a hell or other audible device, 124, which is securely mounted on the inner side of the plate, 11. On the flattened side of the rock-shaft, 62, I securely mount the hammer, 125, so that it will normally be spaced from the bell, 124, as is shown in Figures 4, 6 and 11 and which is adapted to strike the bell the instant the operator releases the downward pressure upon the key, 15, unless he has completed the full downward oroperntive stroke.

Operation.

In the operation of my automatic control and audible andvisible signal, as when the key, 15, is depressed by the operator, it comes in contact with the main; lever which pulls the main control lpiece, .28,- forward,-

pivot,:95, thus raising the rearward end, 43,

and theangular arrn,i44,=of= thei arm, 42. The upward. movement of the-end, 45, of the arm, 44, lifts the pawllifting. arm, 68, sufticiently to'raise the down-p'a-wl,;48, to disengage it from the ratchet teeth, 30.; ;At this timethe downspawl disengage support, 82, is 1 permitted to rock forwardly about its pivot,

83, to permit the ledge, .81, to-engage beneath the extension,- 80, of the pawl lifting arm, 68, and hold it in its elevated position, asis clearlyshown in Figure- 6.

13yreason of the spacing rod, 87, being supported between the pawl liftingarm, 68,

and the tip-pawl, .49,the.raising of the-arm,

68, of course, permits the pawl, -49, to corre- -spondingly raise, by reason of the coil spring, 86. In this manner, the up pawl,

49, engaging the ratchet-teeth, 31, on the under side of the main control piece, 28, prevents the depression of said key until a full up stroke has been completed.

When the operator, after partially depressing a key, 15, removes his finger therefrom, the key returns a very slightdistance upwardly, which upward movement simultaneously locks all of the keys in the several columns, and in addition thereto sounds the audible signal, 124. This is accomplished by means of the down-pawl, 48, which, haw

ing been in a sliding engagement with the ratchet teeth, 30, of the main control piece, 28, is now engaged by one of the teeth, 30, and pushed rearwardly against the tension of the coil spring, 92.

The rearward movement of the pawl, 48, is comparatively very slight and is limited, of course. by the elongated slot. 52, with respect to the shaft, 50, upon which the pawl is mounted. The slight rearward movement of the down pawl, 48, is sufficient to cause the downwardly bent end, 55, thereof, to engage the arm, 56, of the control lever stop hook release, 57, and rock the rod or bar, 58. The rocking movement of the dog, 59, is sufticient to release the lever stop hook, 61, and cause the shaft or rod, 62, to rock slightly. \Vhen the lever stop hook, 61, has moved downwardly, all of the columns of keys will be effectively locked by reason of the fact that a lever stop hook is provided for each column, all being mounted upon the same rock, 62. and are adapted to engage the cutout portions, 36, formed in the upper end of each of the main control pieces. As has been already explained, the hammer, 125, will, at this moment, strike the bell, 124, and sound the audible alarm, which will permit the operator to glance at the key board, and readily complete the operation by the continued downward pressure of the partially depressed key, 15. The fact that the key, which has been partially depressed indicating an incomplete stroke, remains in that position instead of returning to its normal or.- in itial; position, of course, provides 'avisible signal for the operator.

When the partially depressed key, 15, is f-nrthendepressed. to complete the, operative stroke, thdrockingLmovementof the lock control, lever, ,40, .lifts the pawl. lifting arm, 6 8,..disenga'ges;thedown-pawl, 48, from it locked position with respect to its teeth, 30, and-the end, 43, ofgthe arm, 42, lifts the lever stop hook, 61, rocks-the shaft, 62, and disengages and unlocks the several columns of keys,

- .What I-claim.is: 1..In= a keyboard-calculating in:u-.hine,.a

plurality of rows of keys,'locking' means common to'each of the keys. for all rows and arranged with respect to the keys so that the partial depression. of any one of said keys will look all the keys in the remaining rows upon release of pressure from said partially depressed key and means associated with said keys whereby the completion of downward pressure upon the partially depressedkey will unlock all the locked keys.

2.- In akeyboard calculating machine, a

plurality of rows of keys, locking means common to each of the keys for all rows and arranged with respect to the keys so that the partial depression of any one of said keys will simultaneously lock all the keys in the remaining rows upon release of pressure from said partially depressed key, and means associated with said keys whereby the completion of downward pressure upon the partially depressed key will simultaneously unlock all the locked keys.

3. In a keyboard calculating machine, a plurality of rows of keys, locking means common to each of keys for all rows, and arranged with respect to the keys so that the partial depression of any one of said keys will lock all the keys in the remaining.

rows, said locking means including a relatively movable toothed member and coacting pawl associated with the keys for retaining the partially depressed key in its lowered position.

4. In a keyboard calculating machine, a plurality of rows of keys, locking means associated with each of the keys for all the rows and arranged with respect to said keys so that the partial depression of any one of the keys will lock all the keys in the remaining rows upon release of pressure from the partially depressed key said locking means arranged to retain said key in its locked position, and movable means for unlocking said remainder of keys when the partially depressed key has been fully or operatively depressed.

5. In a keyboard calculating machine, a plurality of rows of keys, locking means common to each of thekeys for all rows.

and arranged with respect to the keys so that the partial depression of any one of said keys will lock all the keys in the reniaining rows, and means associated with said keys whereby the completioniof down ward pressure upon the partially depressed key will unlockthelocked keys said locking means includin mechanism for retaining said partially (fepressed key in its partially depressed position.

(3. In a keyboard calculating machine, a plurality of rows of keys, locking ,means common to each of the keys for all rows and arranged with respect to the keys so that the partial depression of any one of said keys will lock all the keys in the remaining rows, said locking means including mechanism associated with the keys for retaining the partially depressed key in its lowered position.

7. In a keyboard calculating machine, a plurality of rows of keys, locking means common to each of the keys for all rows and arranged with respect to the keys so that the partial depression of any one of said keys will simultaneously lock all the keys in the remaining rows, and means associated with said keys whereby the completion of downward pressure upon the partially depressed key will simultaneously unlock the locked keys, said locking means including mechanism operated by said partially depressed key for retaining it in its partial key-stroke position.

8. In a keyboard calculating machine, a plurality of rows of keys, means for automatically locking all the keys in the remaining rows by the partial depression of any one of said keys and means whereby the said remainder of keys will be automatically unlocked by the complete depression of said partially depressed key, said automatic locking means including mechanism associated with the keys for retaining the partially depressed key in its lowered position, said partially depressed key being subject to detention to various depths thereby providing a visible indication of the partially depressed key.

9. In a keyboard calculating machine, a plurality of rows of keys, locking means common to each of the keys for all rows and arranged with respect tqthe keys so that the partial depression of any one of said keys will lock all the keys in the remaining rows, said locking means including mechanism for retainin the partially depressed key in its partial keystroke position thereby providing a visible indication of said last named key, said partially depressed key being. subjectto detention to various depths and means associated with said keys whereby the completion of downward pressure upon the partially depressed key will unlockall of said locked rows of keys on the keyboard.

10;, In a key board calculating machine, a

plurality of rows of keys, means whereby the;

partial depression of' anyone .of thekeys will automatically lock, the remaining rows of keys, said means including a key control lever having notched portions outwardly ex tending lugs carried byeach' of said keys adapted for engagementby said notched portions, and mechanism associated with and operated by said key control lever for retaining it in its partial key-stroke position.

11. In a keyboard calculating machine, a plurality of. rows of keys, means whereby the partial depression of any one. of the keys will automatically lock the remaining rows of keys, said means includinga key control lever having hook portions, outwardly extending pins carried by each of said keys adapted for engagement by said hook portions and mechanism associated with and operated by said key control lever for retaining it in its partial key-stroke position, and means for automatically unlocking said remainder of rows of keys operated by completely depressing the partially depressed key.

12. In a keyboard calculating machine, a plurality of rows of keys, each of said keys havin a single key stem and a unitary head carrieu thereby, locking means common to each of the keys for all rows and arranged with respect to the keys so that the partial depression of any one of said keys will lock all the keys in the remaining rows, said locking means including mechanism for retaining said partially depressed key in its various stages of its lengthwise movement, and means associated with said keys whereby the completion of pressure upon the partially depressed key will unlock all said locked rows of keys on the keyboard.

13. In a keyboard calculating machine, a plurality of rows of keys, locking means common to each of the keys for all rows and arranged with respect to the keys so that the incomplete depression of any one of said keys will lock all the keys in the remaining rows said locking means including mechanism operated by said partially depressed key for retaining it in its partial key-stroke position thereby providing a visible Indication of an incomplete keystroke, and an aud'i'ble signal, said visible indication occurring simultaneously with the operating of the audible signal and the lockin' of said remaining rows of keys on the keyboard;

key for retaining it in its partial key-strokeposition thereby providing a visible indication of an incomplete key-stroke, an audible signal, said visible indication occurring simultaneously with the operating of the audible signal and the lockin of said remaining rows of keys on the key board, and means associated with said partially depressed key whereby the completion of downward pressure upon the partially depressed key will unlock all of said locked keys on the keyboard again placing the machine in its operative position.

15. In a keyboard calculating machine, a plurality of rows of keys, locking means common to each of the keys-for all rows and arranged with respect to the keys so that the incompleted depression of any one of said keys will lock all the keys in the re maining rows, said locking means including mechanism operated by said partially de pressed key for simultaneously retaining it in its partial key-stroke position thereby providing a visible indication of the incomplete stroke, an audible signal, said audible and visible indications being simultaneous, and means associated with said keys whereby the completion of a downward pressure upon the partially depressed key will unlock all said locked rows of keys on the entire keyboard, returning the keyboard to its operative position.

16. In a keyboard calculating machine, a plurality of rows of keys, locking means common to each of the keys for all rows and arranged with respect to the keys so that the partial de )ressiou of any one of said keys will lock a l the keys in the remaining rows, and said locking means including mechanism associated with the keys .for retaining the partially depressed key in its lowered position thereby providing a visible indication of said partially depressed key, said partially depressed key being subject to detention to various depths.

17. In a keyboard calculating machine, a plurality of rows of keys, means associated with the keys for retaining a partially depressed key in its lowered position, locking means common to each of the keys for all rows and arranged with respect to the keys so that the partial depression of any one of said keys will lock all the keys in the remaining rows, each row includin a key control lever, a main control member operatively connected thereto, a movably mounted bar having means carried thereby adapted to engage said main control members for locking all of said remaining rows, and means for unlocking all of said locked keys on the keyboard operable by the completion of down- Iyard pressure upon said partially depressed 18. In a keyboard calculating machine, a. plurality of rows of keys, means associated with the keys for retaining "a. partially depressed key in its -lowered position, locking meanscommon to each of thekeys for-all rows and arranged with respect to the keys so that the partial depression'oi any one of said keys will look all the keys in the remain ing rows-each row including a key control lever, -a main control member operatively connected thereto and provided Wllill a cutout portion and atransversely extending and movably mounted shaft havinga plurality of pawls arranged to 'cnga e the cut-out portions in said main contro members, and means for unlocking all of said locked keys on the keyboard 'operably by the completion of downward pressure upon said partially depressed key.

19. In combination with rows of keys in a keyboard calculating machine, latching devices common to each row of keys normally in inoperative position for retaining the keys in each of the rows from depression, means for releasing said latching devices by incompletc depression and release of a key and for holding said key from rising from its incompletely depressed position includin a key control lever and a main control mem r operatively connected thereto, and having a toothed portion engaged by said latching devices, said releasing means having provision for retaining said partially depressed key in its lowered position, and means for resetting the latching devicesto inoperative position by complete depression of said key.

20. In combination with rows of keys in a keyboard calculating machine, latching devices common to each row of keys normally in inoperative position for retaining the keys in each of the rows from depression, means for releasing said latching devices by incomplete depression and release of a key, and for holding said key from rising from its incompletely depressed position includin a key control lever, and a main control member operatively connected thereto and having provision for retaining the partially depressed key in its lowered position, and means for resetting the latching devices to inoperative position by complete depression of said key.

21. In a calculating machine having a plurality of rows of keys and a key control lever for each row, the combination with latching devices for engaging said control lever to hold the keys fromdepression and comprising a transversely arranged movable shaft and pawls carried by said shaft and adapted to engagethe control lever, means arranged for release by incomplete ,depression of a key for moving said shaft and pawls into operative position and means operated by complete depression of said key for restoring said shaft and pawls to inoperative position.

22. An attachment for a keyboard calculating machine'having a plurality of rows of keys, comprising latching devices common to each row of keys normally in inoperative po sition for retaining the keys in each of the rows 'from depression, means for releasing said latching devices by incomplete depression and release of a key, and for holding said key from rising from its incompletely depressed position, and means for resetting the latching devices to inoperative position by complete depression of said key.

23. An attachmentfor a keyboard calculating machine having a-plurality of rows of keys, comprising locking means common to each of the keys for all rows and arranged with respect to the keys so that the partial depression of any one of said keys will lock all the keys in the remaining rows upon release of pressure from said partially depressed key, said locking means including means for retaining 'said partially depressed key in the various stages of its lengthwise movement, said retaining means including mechanism for controlling the upstroke of said partially depressed key when fully depressed and means associated with said keys whereby the completion of pressure upon the partially depressed key will unlock all said locked rows of keys on the keyboard.

- JOHN H. F. SILVER.

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