US2646927A - Interlocking mechanism fob - Google Patents

Description

.July 28, 1953 c. F. WEBB INTERLOCKING MECHANISM FOR CALCULATING MACHINES v Original Filed Dec. 9, 1959 7 Sheets-Sheet' l /fz vento( Hamai/w55 YY/5w, y 711%,

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C. F. WEBB July 28, 1,953

INTERLOCKING MECHANISM FOR CALCULATING MACHINES 7 Sheets-Sheet 2 Original Filed Dec. 9. 1939 Atto/neas July 28, 1953 C. F. WEBB INTERLOCKING MECHANISM FOR CALCULATING MACHINES Original Filed Dec. 9, 1959 7 Sheets-Sheet I5 48 43 49 al 'so /n venfor 6%.. y www Attorneys.

C. F. WEBB July 28, 1953 INTERLOCKING MECHANISM FOR CALCULATING MACHINES 7 Sheets-Sheet 4 Original Filed Deo.

gyda/.4.0 f A [Iomega 2 Tim July 28, 1953 c. F. WEBB 2,646,927

INTERLOCKING MECHANISM FOR CALCULATING MACHINES Original Filed Deo. 9, 1939 7 Sheets-Sheet 5 /hvenfor c. F. WEBB 2,646,927

INTERLOCKING MECHANISM FQR CALCULATING MACHINES July 28, 1 953 7 Sheets-Sheet 6 Original Filed Deo. 9, 1959 Fig. 11.

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[forneys C. F. WEBB July 28, 1953 INTERLOCKING MECHANISM FOR CALCULATING MACHINES 7 Sheets-Sheet 7 Original Filed Dec. 9, y1939 Patented Juy 2.8-, 195'?,j

UNITED STATES PATENT OFFICE INTERLOCKING MECHANISM FOR CALCULATING MACHINES Christopher Frederick Webb, Uxbridge, England,

assigner to Bell Punch Company Limited, London, England, a British company cember 19, 1938 17 Claims. 1

This invention relates to calculating machines of the key controlled multiple bank type and has for its object to provide improved means for locking the keys of the machine subsequent to a failure on the part of the operator to depress a key to its full extent.

The application is a continuation of my application Serial Number 535,330, filed May 12, 1944, now abandoned, as a continuation of my application Serial Number 308,347, led December 9, 1939, now abandoned.

The invention comprises a calculating machine of the type aforesaid which is so constructed that if a plurality of keys is simultaneously or substantially simultaneously depressed and released and at least one of said keys receives an incomplete depression, all of the said keys are prevented from restoring fully to normal position and all keys except the key or keys incompletely actuated are locked against further depression.

The accompanying drawings show one manner of carrying the invention into effect.

Figure 1 is a perspective view showing part of a calculating machine constructed in accordance with the invention.

Figure 2 is a cross-section through the machine showing the mechanism associated with each bank or line of keys, the mechanism being in the at rest position and certain parts of the key locking arrangement being omitted.

Figure 3 is a View similar to Fig. 2 but showing the 9 key depressed almost to its fullest extent and the driving rack about to engage the figure wheel pinion.

Figure 4 is a View similar to Figs. 2 and 3 showing the 9 key depressed to its fullest extent and the driving rack in engagement with the figure wheel pinion.

Figures and 6 are detail cross-sections respectively on the lines V-V and VI-VI Fig. 2.

Figures '7 to 10 show the driving rack at various stages of its operative movement.

Figure 11 is a side elevation showing the mechanism at the rear of each bank or line for causing locking of the keys on a false key stroke, the 9 key being shown in the fully depressed position.

Figure l2 is a view similar to Fig. 11 but showing the parts of the mechanism in the positions which they occupy after an incomplete depression and release of a key.

(Cl. 23S-130) Figure 13 is a view similar to Figs. 11 and l2 f showing the parts in the positions they occupy when a key which has received an incomplete depression is subsequently depressed to its full extent.

Figure 14 is a view similar to Fig. 13 showing in interrupted lines the position to which the key restores after depression to the position shown in Fig. 13 and in full lines its restoration to correct initial position on actuation of a clearing handle.

Figures 15 and 1-6 are cross-sections respectively on the lines XV--XV and XVI-XVI, Fig. 12.

Figures 17 and 18 are respectively a side and rear view of the clearing handle with its associated parts.

Referring to the drawings the calculating machine comprises an outer case 2B having the keys arranged at its upper side. The front of the case is inclined as shown in Fig. 1 and in this front is formed an elongated aperture through which the numbers on the gure wheels 2l can be viewed. In the example shown, a facia strip 22 is provided in the aforesaid aperture, the strip 22 being formed with holes for viewing the numbers and having a glass strip covering its outer side. Each bank 0r line contains 9 keys numbered 1 9, as many lines as desired being provided, and each line is associated with a system of linkages directly operable by any of the keys in the line in question to rotate the gure wheel associated with that line.

A line of keys and associated linkages is illustrated in Figs. 2-4 and as shown each key comprises a stem 23 arranged to slide in a slot in a cover plate 24, the stem being provided with the usual key top 25 and with a shoulder 26 for engaging a driving bar 21 extending longitudinally oi the line below all the keys therein. The lower portion of each key stem 23 is guided in a slot in a plate 28 secured to or formed integrally with a frame plate 29 which serves to separate the line from the adjacent line. Each key is also provided as best shown in Figs. 15 and 16 with a hole 30 situated immediately above the shoulder 25 and is shaped at its lower end to the form of a fork 3l as shown in Fig. 5. Also each key stem is associated with a spring 32 for restoring the key to its normal position after depression, the upward movement of the key being limited by abutment of a second shoulder 33 on the key stem against a part (not shown) at the under side of the top plate`24. When the keys are in their rest positions their lower ends are at the same horizontal level as shown in Fig. 2.

The driving bar 21 is arranged for movement in a vertical plane and is mounted in such a manner that during its vertical movement it also moves longitudinally through a small distance in va rearward direction. In the example shown,

the bar 21 is pivotally connected at its rear end at 34 to one arm of a bell crank 35 rotatably mounted on a iixed spindle 3S extending transversely through all the lines in the machine. Near its front end the driving bar 2 is supported by a T-shaped member 3l rotatably mounted on a fixed spindle 3B extending parallel to the spindle 36 transversely through the machine, one arm of the T-shaped member 3'! being pivotally connected as shown with the bar 27 through the intermediary of a short link 35. The driving bar is also formed as shown clearly in Figs. 2-4 with a series of hook-shaped projections 4G, one for each key, each hook being shaped to form an upper abutment surface lil and below this surface a protuberance 42. The mounting of the bar 2T is such that on depression of a key the bar moves rearwardly through a short distance to cause the appropriate protuberance 42 to move into the hole in the stem of the key depressed, the object of this engagement of the protuberance in the hole being hereinafter explained.

Below the driving bar 21 and extending parallel thereto is a stop bar 43, the latter being pivotally connected at its rear end by means of a pin 44 to the lower arm of the bell crank 35 and being pivotally connected near its front end at 45 to an arm of the T-shaped member 3?, also the pin 44 projects beyond the bell crank 35 for a purpose explained below. The arrangement is therefore such that when the driving bar 2l is depressed on actuation of a key the stop bar 43 moves forwardly in a direction towards the gure wheel 2l. The keys are so arranged that during the latter part of their downward movement their forked lower ends 3l straddle the stop bar 43. Also the stop bar is formed in its upper side with a series of recesses 45 terminating in vertical abutment surfaces 4i arranged to contact with a depressed key stem as hereinafter described to limit depression of the key and movement of the driving bar 2l' and stop bar 43. A recess 45 is provided for each key with the exception of keys Nos. 1 and 9, the abutment surface for key No. l being constituted by the front end of the stop bar. Since the key No. 9 when fully depressed shifts the rack the full extent of its movement, no abutment is required therefor. Also the stop bar 43 is formed at its lower side and near its rear end with a tooth 48 engageable by the pawl 49 in the circumstances and for the purpose described below, the pawl 49 being pivotally mounted at its rear end on a pin 5, Figs. ll-14, carried in the upper ends of the arms of a LJ-piecel 5l rotatably mounted on a spindle 52 extending transversely through the machine. The U-piece 5!A is also formed with a tail 53 of the shape shown in Figs. 11-14, 'the rear end of this tail being arranged to abut against the upper side of a bar 54 extending behind all the lines in the machine. The-bar 54 is provided with bent ends 55 rotatably mounted on the spindle 52, the bar 54 being subjected to the action of a spring 55 tending to swing the bar in an upward direction. rfne pawl 4S is also associated with a spring 5T normally tending to hold the front end of the pawl against the underside of the stop -bar 43 as shown in interrupted lines in Fig. 2'.

Pivotally mounted on a spindle 5S extending completely through the machine is a bell crank 5g having the end 59 of one arm shaped to the form shown in Figs. 11-14, the end 5I of its other arm being bent at right angles to the said arm. This bell crank is associated with a spring 62 tending to rotate the bell crank in a counterclockwise direction as viewed in Figs. 1l14 and normally the bell crank is located in the position shown in Fig. 1l with its end abutting against the front side of the bar 54. Also extending :completely through the machine at the rear of each line therein is a releasing bar 63 pivotally mounted by means of its in-turned ends 64 on the spindle 52, one end 54 being provided with a handle 55, Figs. 1, 1'? and i8, projecting through a slot 65 in the Casework 2G of the machine, actuation of the handle 65 serving to swing the bar 63 in a counterclockwise direction as viewed in Figs, 1l-l4 to move the same into engagement with the lower arm of the bell crank 59, for the purpose hereinafter described.

t will be understood that the bell crank 59 and the pawl 49 and its associated parts above described are reproduced in each line in the same way as are the driving bar 2i, stop bar 43, and their associated parts.

The ligure wheel 2l is rotated on actuation of a key by a rack G1 having 10 teeth adapted to engage and rotate a lG-tooth pinion 38 connected to the figure wheel. The rack 6. is formed at the front end of' an arm 69 rotatably mounted at its rear end on a pin 'iii carried in the lower ends of the arms of an inverted U-piece ll' rotatably mounted near its upper end on a spindle 'i2 extending completely through the mach-ine. The arm B9 is formed near its front end with an open ended slot 'E3 of the configuration shown in which engages a roller 14 carried at the lower end of a part 'i5 pivotally mounted at its upper end on a spindle 'i6 extending transversely through the machine. The part 15 is connected by a link 'il with an arm of the T-shaped member 3i', the arrangement being such that rotation of the T-shaped member in a clockwise direction around its spindle 38 serves to swing the part 'i5 in a counterclockwise direction around its spindle le to cause the roller T4 to move into the slot T3 to swing the arm 69 in an upward direction. In the position of rest shown in Fig. 2 the location of the U-part H is such that the rack B7 is held away from the teeth of the pinion E8 and can be swung through an angle into the position shown in Fig. 3 without influencing the pinion.

Extending longitudinally of the line below all the keys therein is a bar i8 `mounted for rotation about its longitudinal axis, the bar being provided with a number of laterally projecting parts l'9 one of which is arranged directly below each key stem so as to be engageable by the latter during its downward movement. As illustrated in Figs; 2 4, the bar l?. is not arranged parallel to the driving bar 2 and the stop bar $3 but is inclined thereto the distance between the lower end of the stem of key No. i and the projection T9 situated below that key being a minimum and the corresponding distance for key No. 9 being a maximum. When a key i5 depressed the distance moved by the driving bar 2'! and the stop bar It?, and hence the angley through which the rack Si swung before the lower end' of the key stem engages its corresponding projection ii) will thus vary for each key. The bar 'i8 is associated with a spring 30 tending to rotate the bar in a direction to move the projections i9 in an upward direction. Also the bar is formed near its rear end with aprojection 8| arranged to overlie the pawl 4) and to engage and depress the same under the conditions hereinafter described.

One arm of the inverted U-part 'H is formed S with a right-angular shaped slot 82 .as clearly shown in Figs. r7 10 and into this slot projects a part 83 secured to or formed integrally with the bar 18. The U-part 1| is also formed with a tail piece 84 to the end of which is secured one end of a spring 85, the other end of which is secured to a hook piece 88 carried on the pin 45 which serves to connect the lower arm of the T-shaped member 31 to the stop bar 43. The anchorages of the spring 85 are arranged as shown in the drawing with respect to the pointsv of pivotation 38 and 12 for the purpose hereinafter described. Also the stop bar -43 is provided with a pin 81 arranged to engage the tail 84 under the conditions explained below.

The operation of the mechanism is as follows:

Normally the parts occupy the positions shown in Fig. 2 with the projection 83 lying in the vertical arm of the slot 82 the rack 61 being held in its lowermost position and away from the pinion 68: also the roller 14 is located at the front end of the slot 13. Additionally the front end of the pawl 49 is engaging the underside of the stop bar 43 and the end of the tail 53 is resting on the upper side of the bar 54 with the end 68 of the bell crank 5S abutting against the front side of the said bar as shown in Fig. 11.

When a key, for example the 9 key, is ydepressed, its shoulder 26 engages the driving bar 21 to move the latter downwardly and the stop bar 43 longitudinally in a forward direction, the rearward motion of the driving bar 21 which also occurs serving to engage the protuberance 42 on the hook 48 corresponding to the 9 key in the hole 30 in the stem of the said key. Immediately before the lower end of the key stem engages its corresponding projection 19 on the bar 18, the parts occupy the positions shown in Fig. 3, the rack having been swung in an upward direction while remaining out of engagement with the pinion 68 and the spring 85 being now in an extended condition by reason of the forward movement of the hook 86, the tail 84 and U-part 1| being retained in their original positions by the engagement of the part 83 in the vertical arm of the slot 82. Also the end of the pawl 49 still abuts against the underside of the stop bar 43, the tooth 48 on the stop bar having passed over the end of the pawl during forward movementr of the bar.

At the completion of the downward stroke of the key the lower end of the stem engages its projection 19 to rotate the bar 18 in a direction to move the part 83 downwardly out of the upper end of the vertical arm of the slot 82, the U-part 1| being thereupon released and being swung in a clockwise direction through a small angle by the spring 85 acting through the tail 84 to move the rack 6l' into engagement with the pinion 68. The depth of engagement of the teeth of the rack with those of the pinion is limited by abutment of the rear end of the slot 82 against the part 83, and the parts now occupy the positions shown in Fig. fi. Rotation of the bar 18 by the key stem also causes the projection 8| to engage the pawl 49 and depress the same away from the stop bar 43, the engagement of the pawl by the projection 8| serving merely to rotate the pawl about its pivot 56 without influencing the remaining parts of the locking mechanism. v

When the key is released the spring 85 acts to rotate the T member 31 in a counterclockwise direction to swing the rack 61 through the various stages shown in Figs. 7410, the rack remaining in'engagement with the Vvpinion and thus rotating the figure wheel during its return stroke. The gure wheel is therefore rotated during the up-stroke of the key. After the rack reaches the bottom of its stroke as shown in full lines in Fig. 10, the pin 81 carried by the stop bar 43, which latter has been moving in a rearward direction during the return stroke of the rack, engages the tail 84 as shown in interrupted lines in Fig. 4 to restore the U-part 1i to its original position, such return of the U-part 1| serving to withdraw the rack 61 from the pinion 68 and the spring 88 serving to rotate the bar 18 to reposition the part 83 in the upper end of the vertical arm of the slot 82. Restoration of the U-part 1| through engagement of the tail 84 by the pin 81 is effected by reason of the fact that the force tending to move the bar 43 in la rearward direction is greater than the force exerted by the spring 85 on the tail 84, this difference in the opposing forces being achieved by the arrangement shown in the drawings of the dimensions and disposition of the parts concerned and of the anchorages of the front and rear ends of the spring 85. Resetting of the bar 18 also permits the pawl 49 to spring upwardly into engagement with the underside of the stop bar 43, the end of the pawl engaging such underside at ia` position in front of the tooth 48. The parts have therefore once again assumed the positions shown in Fig. 2.

As previously explained and as will be apparent from the foregoing, the angle through which the rack 61 is swung before it is moved into engagement with the pinion, and therefore the angle through which the iigure wheel is rotated during the return stroke of the rack, will vary according to the key depressed. In effect, each key serves to pre-select the rack through a predetermined distance before moving it into engagement with the pinion and the parts are so arranged that actuation of the rst key rotates the iigure wheel through an angle of 36, the second key 72, and so on up to the ninth key which rotates the figure wheel through lan angle of 324.

Also the arrangement is such that the angular velocity of the figure wheel is reduced to zero or substantially to zero by suitable deceleration of the rack before the latter disengages the pinion. This, has the effect of preventingvoverthrow of the wheel, the latter in the present instance being brought to rest in its correct position before it is freed by the rack. The rack is decelerated towards the end of its stroke by shaping the slot 13 to the coniiguration shown in the drawings, such a shape of the slot causing the rack to be accelerated during the initial stages of its return stroke but when the roller 14 reaches approximately the position shown in Fig. 9 the rack commences to decelerate until eventually it 4cornes to rest momentarily in the position shown in full lines in Fig. 10. The rack reaches this latter position immediately before the pin 81 engages the tail 84 so that the rack is moved out of engagement with the pinion 68 only after the latter, and therefore the iigure wheel 2|, has 'been brought to rest. If desired the roller 14 may be replaced by a pair of rollers or pins at the end of the part 15 arranged to move along opposite sides of a bar or the like formed integrally with the arm 69, such bar or the like being shaped to produce the eiect provided by the roller 14 and slot 13.

If the operator fails inadvertently to depress a key to its fullest extent the key stem does not engage its corresponding projection 19` on the bar 18 and the rack 61 is therefore not'released into engagement with. the pinion. The bar 78 does not therefore cause the pawl 49 to be moved away from the stop bar 43 and hence when the key is released and the stop bar 43 starts to move rearwardly the pawl 49 is engaged by the tooth 49 as shown in Fig. 12 and is moved bodily in a rearward direction to swing the part l in a clockwise direction around its pivot 52 into the position shown in Fig. 12, the tail 53 depressing the bar 54 against the influence of its spring 56 into contact with a stop edge 90 and the parts coming to rest with the stop bar 43 held against further rearward movement and away from its normal rest position. As the driving bar 2'! has failed to return to initial position, the key which has been depressed is unable to restore fully owing to the engagement of the appropriate protuberence 42 in the hole 30 in the key stem, the key being held in the position indicated in full lines in Fig. l2. In the latter gure the normal rest position of the key is shown in interrupted lines and the lowest position to which the key was depressed during the false key stroke is also shown in interrupted lines.

As will be clearly apparent from Fig. 12 if an attempt is now made to depress another key in the line containing the incompletely depressed key the shoulder 2S of the said other key will engage the upper side of its corresponding protuberance 42 and will move the driving barv 2l downwardly an extremely small amount only, the abutment surface 4l above the said protuberance 42 engaging the key stem of the other key after a very small downward movement of the driving bar 21 by reason of the rearward movement of the bar. Such abutment of the surface 4| against the key stem will therefore serve to prevent downward movement of the said other key so that to all intents and purposes the said other key can be regarded as locked. Hence, therefore, after a key has been incompletely depressed and released the remaining keys in the line containing that key are locked against depression.

Also movement of the bar 54 downwardly from the position shown in Fig. 11 to that shown in Fig. 12 will permit the bell crank 59 to be swung in a counter-clockwise direction by its spring 62, such movement of the bell crank serving to move the bent end 6l into a position behind the pin 44 at the rear end of the stop bar 43. Such movement of the bell crank 59 is limited by abutment of its lower arm against the release bar 53. Downward movement of the bar 54 also however serves to release the bell cranks 59 in all the remaining lines of the machine and each of these bell cranks rotates into a position wherein its bent end 6l lies in front of the pin 44 on the corresponding stop bar 43 so as to hold the stop bar against lforward movement; hence, therefore, all the keys in the remaining lines in the machine are locked against depression. Thus failure of the operator to depress a key to its fullest extent results in the locking up against further movement of the entire keyboard with the exception of that particular key which was incorrectly actuated. Additionally, the top of the key in question is held at a position below that which it normally occupies so that the key is capable o immediate visual identification.

fter the false stroke the key can then be depressed to its full extent and released, this serving to enter the correct figure on the figure wheel. Full depression of the key to the position shown in full lines in Fig. 13 will now cause the bar 18 to be actuated to release the rack 6'1 into erigagement with the pinion 63 and also to move the pawl 49 out of engagement with the underside of the stop bar 43. When the key is released subsequent to the full depression, the rack 61 is swung in a downward direction to rotate the figure wheel and the stop bar 43 moves rearwardly until it is arrested by engagement of its pinV 44 against the bent end El of the bell crank lever 59 as shown in dotted lines in Fig. 13. Such arrest of the stop bar 43 occurs immediately before the pin 81 is due to engage the tail 84 and therefore when the stop bar is arrested the rack 51 is still in engagement with the pinion 68 although it has completed rotation of the same. Hence, any other attempt to depress the key will tend to rotate the pinion in a direction opposite to that in which it is rotated during the normal operative stroke of the rack and as this pinion is associated with the usual non-return pawl 68 no further downward movement of the key is permitted and therefore the entire keyboard is now locked. However, as the stop bar 43 in the line containing the incompletely depressed key is not fully restored to normal position the said key will again be retained on its release in a position below its normal position by reason of the engagement of the appropriate protuberance 42 in the hole 39 in its key stem.

t will be apparent that the false stroke has had no iniiuence on the calculation since the rack was not moved into engagement with the pinion on release of the key subsequent to the false stroke; hence the subsequent correct depression of the key on which the false stroke was made will bring the calculation to exactly the same condition as if the false stroke had never occurred.

The keys of the machine are unlocked after correction of the error and to permit the calculation to be proceeded with, by actuating the handle E5 in a forward direction, such actuation serving to move the bar 63 to rotate the bell cranks 59 in a clockwise direction as viewed in Figs. 11-14. Such movement of the bell cranks will now permit the bar 54 to be restored to its original position under the influence of its spring 56 and furthermore, the stop bar 43 which has been held out of its rest position is now permitted to return to such position so as to permit restoration to its original position of the key which was incorrectly depressed. The machine is now in a condition wherein the calculation can be proceeded with, the error having been corrected Without the necessity of zeroising the gure wheel and starting the calculation afresh.

The foregoing describes the eiect produced by incomplete depression of a single key, this key being the only one of the keyboard which is actuated. If, however, a plurality of keys is actuated simultaneously, one of which does not receive a full depression, all the keys which were actuated, including not only the key on which the false stroke was made but also the remaining keys which were fully depressed, are prevented on their release from fully restoring to their initial positions. This result is achieved by reason of the fact that the faulty key stroke serves, as previously described, to move the bar 54 downwardly to release the bell cranks 59 in all the lines in the machine which bell cranks thereupon swing in a counterclockwise direction and as this swinging movement is completed before the full restoration of the stop bars 43 in the lines containing the correctly depressed keys, the pins 44 on each of said stop bars are obstructed by the corresponding bent ends 6| of the bell cranks to prevent full restoration of the driving bars. The latter are held in a position wherein their respective racks 6l have rotated the pinions B8 through the correct amounts but have not become disengaged therefrom so that the keys in the lines containing the correctly depressed keys become locked sin-ce any attempt to depress these keys will tend to rotate the pinions 68 in a counterclockwise direction which will be prevented by the non-return pawls aforementioned. As, however, the stop bars 43 in the lines containing the said correctly depressed keys have not completely restored to initial position each of the said keys is also prevented from being fully restored and the entire combination of actuated keys including the faulty key becomes immediately apparent from a visual inspection of the keyboard. It will be apparent that the keys in the lines in which no key was depressed are also held locked by reason of the location of the bent ends 6l in front of the pins @.4 so that in effect all the keys of the machine are locked with the exception of the incompletely depressed key.

lf now the handle 65 is actuated, the bell cranks 59 are swung in a clockwise direction and in all those lines in which the keys were properly depressed, the stop bar 43 is permitted to restore to initial position thus allowing the key in that line to rise into its normal position. However, the stop bar 43 in the line containing the incompletely depressed key will not be permitted to restore to initial position because of its engagement by the pawl 49 and hence actuation of the handle 65 will not aifect the position of the key which received the false stroke. Hence, therefore, when a plurality of keys is simultaneously or substantially simultaneously depressed and released and one of these keys receives an incomplete depression, all the said keys will fail to restore completely and if subsequently the handle G5 is actuated, the keys which did receive a complete depression will restore to initial position while that key which was incorrectly actuated will remain in a depressed condition. Thus the incompletely depressed key is differentiated from those completely depressed.

rihe above feature is of great advantage to the operator who is not only immediately notied u 65 the operator can then eliminate those keys n which were completely actuated and correct the calculation by merely completely depressing the key which remains depressed after actuation of the handle '65. The feature of preventing the full restoration of not only the key which received the false depression but also of the other keys which were actuated simultaneously avoids the operator having to remember the particular amount added into the machine when the fault occurred and this in practice is found to be of great utility as the operator may have moved her iingers on to another combination of keys or may have had her attention distracted between the making of the reror and its discovery by a subsequent attempt to add in another amount. In machines now in use, if, as frequently occurs in practice, the operator is not sure of the precise combination of iigures at ywhich the error occurred, the machine has to be zeroized and the calculation started afresh.

After the error has been corrected by depression of the key which was incorrectly actuated, the calculation may be proceeded with as hereinbefore described after a further actuation of the handle 65 without the necessity of Zeroizing the machine.

It will be apparent that if during depression of a plurality of keys two or more fail to receive a complete depression all the latter keys will remain in a depressed condition after actuation of the handle E5 so asfto enable the operator to detect the faulty keys and correct the calculation by a full depression of each. A subsequent further actuation of the handle 65 will then enable the calculation to be proceeded with.

In calculating machines which are intended for operation at high speed it sometimes occurs that during depression of a key an adjacent key in the same line, for example the key immediately below the key depressed, is accidentally touched and moved by the operators finger and it is necessary that the machine should be so constructed that such accidental movement of the other key shall in no way aiect the calculation. It will be ap- I,parent that the present machine complies with this requirement since initial depression of the correct key will have movedl the driving bar 2l to a position wherein the hook 40 corresponding to the adjacent key which is accidentally touched lies below the said key and hence when the adjacent key moves downwardly as a result of the accidental depression its shoulder 25 will ride on the top of the hook and its key stem can therefore never reach a suiliciently depressed position to release the rack. Hence, the leading correct key is the only onewhich will influence the gure wheel.

The invention is not limited to the example described as subordinate details of construction may be varied to suit individual requirements. For example, instead of providing the holes 39 in the key stems they may be formed in llaterally extending projections on the bar 2l and arranged to cooperate with projections on the key stems.

What -is claimed is:

1. A key-powered calculating machine comprising a plurality of banks of keys, a plurality of pinions, one associated with each bank of keys, a movable rack for each bank of keys adapted to drive the corresponding pinion, means for moving each rack, upon depression of a corresponding key, in one direction while out of mesh with its pinion, and, upon release of said key; in vthe opposite direction in mesh with its pinion with release, normally, therefrom at the end of its movement, said means including a member extending longitudinally below each bank of keys, connected to the corresponding rack, and arranged tc be moved upon actuation of any key of its bank, means controlled by the member Aof thefbank in which a key is incompletely depressed for preventing Ifull restoraltion vof a member in another` bank in which a key -is depressed, means effective untilthe last kmentioned member is restored to prevent restoration to normal position of the key which effected its movement, means eiective until the last mentioned member is restored to prevent disengagement of its corresponding rack from its pinion after at least substantial completion of its rotation cf its pinion, and a pawl preventing reverse rotation of each pinion, so that there is locked against movement each key of the bank in which such disengagement is prevented.

2. A key-powered calculating machine comprising a plurality of banks of keys, a plurality of pinions, one associated with each bank of keys, a movable rack for each bank of keys adapted to drive the corresponding pinion, means for moving each rack, upon depression of a corresponding key, in one direction while out of mesh with its pinion, and, upon release of said key, in the opposite direction in mesh with its pinion with release, normally, therefrom at the end of its movement, said means including a member extending longitudinally below each bank of keys, connected to its corresponding rack, and arranged to be moved upon actuation of any key of its bank, means controlled by the member of the bank in which a key is incompletely depressed for preventing full restoration of a member in another bank in which a key is depressed, means effective until the last mentioned member is restored to prevent restoration to normal position of the key which effected its movement, means eiective until the last mentioned member is restored to prevent disengagement of its corresponding rack from its pinion after at least substantial completion of rotation of its pinion, a pawl preventing reverse rotation of each pinion, so that there is locked against movement each key of the bank in which such disengagement is prevented, and means preventing restoration cf the member of the bank in which said key is incompletely depressed.

3. A key-powered calculating machine comprising a. plurality f banks of keys, a plurality of pinions, one associated with each bank of keys, a movable rack for each bank of keys adapted to drive the corresponding pinion, means for moving each rack, by depression of a corresponding key, in one direction while out 0f mesh with its pinion, and, upon release of said key, in the opposite direction in mesh with its pinion with release, normally, therefrom at the end of its movement, said means including a member extending longitudinally below each bank of keys, connected by a linkage to the corresponding rack, arranged to be moved by actuation of any key of its bank, and which, when in its normal fully restored position, serves to effect said release of the rack from its pinion, means controlled by the member of the bank in which a key is incompletely depressed and released for preventing full krestoration of a member in another bank in which a key is depressed, and thereby preventing release of the rack in the last mentioned bank from its pinion, and means eective until the last mentioned member is restored to prevent restoration to normal position of the key which effected its movement.

4. A key-powered calculating machine cornprising a plurality of banks of keys, a plurality of pinions, one associated with each bank of keys, a movable rack for each bank of `keys adapted to drive the corresponding pinion, means for moving each rack, by depression of a corresponding key, in one direction while out of mesh with its pinion, and, upon release of said key, in the opposite direction in mesh with its pinion with release, normally, therefrom at the end of its movement, said means including a member extending longitudinally below each bank of keys, connected by a linkage to the corresponding rack, arranged to be moved by actuation of any key of its bank, and which, when in its normal fully restored position, serves to effect `said release of the rack from its pinion, said member being provided `with a plurality of key engaging (ifi 12 devices, one for each key, each key having a portion engageable by the corresponding key engaging device, means causing said member to prevent restoration of a depressed key to normal position in the event of incomplete depression and release thereof by engagement of such incompletely depressed key by the corresponding key engaging device, the last mentioned means preventing restoration of said longitudinally eX- tending member, and means, operative upon complete depression of said partially depressed and released key and release following said complete depression, to prevent a subsequent depression thereof, the means last mentioned acting to prevent movement of the longitudinally extending member to an extent suiicing to release said rack from its pinion.

5. A key-powered calculating machine comprising a plurality of banks of keys, aplurality of pinions, one associated with each bank of keys, a movable rack for each bank of keys adapted to drive the corresponding pinion, means for moving each rack, by depression of a corresponding key, in one direction While out of mesh with its pinion, and, upon release of said key, in the opposite direction in mesh with its pinion with release, normally, therefrom at the end of its movement, said means including a member extending longitudinally below each bank of keys, connected by a linkage to the corresponding rack, arranged to be moved by actuation of any key of its bank, and which, when in its normal fully restored position, serves to eiect said release of the rack from its pinion, said member being provided with a plurality of key engaging devices, one for each key, each key having a portion engageable by the core responding key engaging device, means causing said member to prevent restoration of a depressed key to normal position in the event of incorn plete depression and release thereof by engagement of such incompletely depressed key by the corresponding key engaging device, the last mentioned means preventing restoration of said longitudinally extending member, means controlled by the member of the bank in which a kei7 is incompletely depressed and released for preventing full restoration of a member in another bank in which a key is depressed, and thereby preventing disengagement of the rack in the last mentioned bank from its pinion, and means eiective until the last mentioned member is restored to prevent restoration to normal position of the key which effected its movement.

6. A. key-powered calculating machine comn prising a plurality of banks oi' keys, a plurality of pinions, one associated with each bank of keys, a movable rack for each bank of keys adapted to drive the corresponding pinion, means for moving each rack, by depression of a corresponding key, in one direction while out of mesh with its pinion, and, upon release of said key, in the opposite direction in mesh With its pinion with release, normally, therefrom at the end of its movement, means including a member extending longitudinally below each bank of keys, connected by a linkage to the corresponding rack, arranged to be moved upon actuation of any key of its bank, and which, when in its normal fully restored position, serves to effect said release of the rack from its pinion, said member being provided with a plurality of key engaging devices, one for each key, each key having a portion engageable by the corresponding key engaging device, means causing said member to prevent restoration of a depressed key to normal amasar position in the event of incomplete depression and release thereof by engagement of such incompletely depressed key by the corresponding key engaging device, the last mentioned means preventing restoration cf said longitudinally eX- tending member, means, operative upon complete depression of said partially depressed and released key and release following said complete depression, to prevent a subsequent depression thereof, the means last mentioned acting to prevent movement of the longitudinally extending member to an extent suiiicing to release said rack from its pinion, means controlled by the member of the bank in which a key is incompletely depressed and released for preventing full restoration of a member in another bank in which a key is depressed, and thereby preventing disengagement of the rack in the last mentioned bank from its pinion, and means effective until the last mentioned member is restored to prevent restoration to normal position of the key which effected its movement.

7. A key-powered calculating machine comprising a plurality of banks of keys, a plurality of pinions, one associated with each bank of keys, a movable rack for each bank of keys adapted to drive the corresponding pinion, means for moving each rack, by depression of a corresponding key, in one direction while out of mesh with its pinion, and, upon release of said key, in the opposite direction in mesh with its pinion with release, normally, therefrom at the end of its movement, said means including a member extending longitudinally below each bank of keys, connected by a linkage to the corresponding rack, arranged to be moved by actuation of any 'key of its bank, and which, when in its normal fully restored position, serves to effect said release of the rack from its pinion, said member being provided with a plurality of key engaging devices, one for each key, each key having a portion engageable by the corresponding key engaging device, means causing said member to prevent restoration of a depressed key to normal position in the event of incomplete depression and release thereof by engagement of such incomp-letely depressed key by the corresponding key engaging device, the last mentioned means preventing restoration of said longitudinally extending member, means controlled by the member of the bank in which a key is incompletely depressed and released for preventing full restoration of a member in another bank in which a key is fully depressed and released, and thereby preventing disengagement of the rack in the last mentioned bank from its pinion, and manipulable means effective following the aforementioned events for fully restoring the last mentioned member but ineffective, in the last mentioned action, to restore the member in the bank in which the key was incompletely depressed and released.

8. A key-powered calculating machine comprising a plurality of banks of keys, a plurality of pinions, one associated with each bank of keys, a movable rack for each bank of keys adapted to drive the corresponding pinion, means for moving each rack, by depression of a corresponding key, in one direction while out of mesh with its pinion, and, upon release of said key, in the opposite direction in mesh with its pinion with release, normally, therefrom at the end of its movement, said means including a member extending longitudinally below each bank of keys, connected by a linkage to the corresponding rack, arranged to be moved by actuation of any key of its bank,

and which, when in its normal fully restored position, serves to effect said release of the rack from its pinion, said member being provided with a plurality of key engaging devices, one for each key, each key having :a portion engageable by the corresponding key engaging device, means causing said member to prevent restoration of a depressed key to normal position in the event of incomplete depression and release thereof by engagement of such incompletely depressed key by the corresponding key engaging device, the last mentioned means preventing restoration of said longitudinally extending member, means controlled by the member of the bank in which a key is incompletely depressed and released for preventing full restoration of a member in another bank in which a key is fully depressed and released, and thereby preventing disengagement of the rack in the last mentioned bank from its pinion, manipulable means effective following the aforementioned events for fully restoring the last mentioned member but ineiective to restore the member in the bank in which the key was incompletely depressed and released, and mea-ns, operative upon complete depression of said partially depressed and released key and release following said complete depression, to prevent a subsequent depression thereof, the means last mentioned acting to prevent movement of the corresponding longitudinally extending member to an extent suiiicing to release said rack from its pinion.

9. A key-powered calculating machine comprising a plurality of banks of keys, a plurality of pinions, one associated with each bank of keys, a movable rack for each bank of keys adapted to drive the corresponding pinion, means for moving each rack, by depression of a corresponding key, in one direction while out of mesh 'with its pinion, and, upon release of said key, in the opposite direction in mesh with its pinion with release, normally, therefrom at the end of its movement, said means including a member extending longitudinally below each bank of keys, connected by a linkage to the corresponding rack, arranged to be moved by actuation of any key or its bank and which, when in its normal fully restored position, serves to effect said release of the rack from its pinion, said member being provided with :a plurality of key engaging devices, one for each key, each key having a portion engageable by the corresponding key engaging device, means causing said member to prevent restoration of a depressed key to normal position in the event of incomplete depression and release thereof by engagement of such incompletely depressed key by the corresponding key engaging device, the last mentioned means preventing restoration of said longitudinally extending member, means controlled by the member of the bank in which a key is incompletely depressed and released for preventing full restoration of a meiber in another bank in which a key is fully depressed and released, and thereby preventing disengagement o the rack in the last mentioned bank from its pinion, manipulable means effective following the aforementioned events for fully restoring the last mentioned member but ineffective to restore the member in the bank in which the key was incompletely depressed and released, and means, operative upon complete depression of said partially depressed and released key and release following said complete depression, to prevent a subsequent depression thereof, the means last mentioned acting to prevent movement of the corresponding longitudinally extending member to an extent sufllcing to release said rack from its pinion.

10. A calculating machine comprising a plurality of banks of keys, means for preventing full restoration to normal position of all of a. plurality of substantially simultaneously depressed and thereafter simultaneously released keys of Which one is incompletely depressed before its release, and means for preventing depression, from the position attained under the action of said preventing means, of any key fully depressed during said simultaneous depression of keys.

ll. A calculating machine comprising a plurality of banks of keys, means for preventing full restoration to normal position oi all of a plurality of substantially simultaneously depressed and thereafter simultaneously released keys of which one is incompletely depressed before its release, means for preventing depression, from the position attained under the action of said preventing means, of any key fully depressed during said simultaneous depression of keys, and means for preventing depression, after such incomplete depression oi a key, of any key not depressed during said substantially simultaneous depression of keys.

l2. A calculating machine comprising a plurality of banks of keys, means for preventing full restoration to normal position of all of a plurality of substantially simultaneously depressed and thereafter simultaneously released keys of which one is incompletely depressed before its release, means for preventing depression, from the position attained under the action of said preventing means, of any key fully depressed during said simultaneous depression of keys, said inco;n pletely depressed and released key being free for complete depression and release, and means for locking the last mentioned key aga-inst further depression following a complete depression and release.

i3. A calculating machine comprising a pluraln ity of banks or keys, means for preventing' full restoration to normal position of all of a plurality of substantially simultaneously depressed and thereafter simultaneously released keys of which one is incompletely depressed before its release, means for preventing depression, from the position attained under the action of said preventing means, of any key fully depressed during said simultaneous depression of keys, means for preventing depression, after such incomplete depression ci a key, of any key not depressed during said substantially simultaneous depression of keys, said incompletely depressed and released key being free for complete depression and re lease, and means for locking the last mentioned key against further depression following a complete depression and release.

14. A calculating machine comprising a, plurality of banks of keys, means for preventing full restoration to normal position of all of a plurality of substantially simultaneously depressed and thereafter simultaneously released keys of which one is incompletely depressed, manipulable means controlling said preventing means and restoring to normal position only the fully depressed keys previously prevented from restoration to normal position, the incompletely depressed key remaining depressed so that it may be visually identified and distinguished from the fully depressed keys.

15. A calculating machine comprising a plurality of banks of keys, means for preventing full restoration to normal position of all of a plurality of substantially simultaneously depressed and thereafter simultaneously released keys of which one is incompletely depressed, manipulable means controlling said preventing means for restoring to normal position only the fully depressed keys previously prevented from restoration to normal position, the incompletely depressed key remaining depressed so that it may be visually identified, and means for preventing redepression of the restored fully depressed keys.

16. A calculating machine comprising a plurality of banks of keys, means for preventing full restoration to normal position of all of a plurality of substantially simultaneously depressed and thereafter simultaneously released keys of which one is incompletely depressed, manipulable means controlling said preventing means for restoring to normal position only the fully depressed keys previously prevented from restoration to normal position, the incompletely depressed key remaining depressed so that it may be visually identified, and means for preventing actuation of said incompletely depressed key following full depression thereof.

17. A calculating machine comprising a plurality of banks of keys, means for preventing full restoration to normal position of all of a plurality of substantially simultaneously depressed and thereafter simultaneously released keys of which one is incompletely depressed, manipulable means controlling said preventing means for restoring to normal position only the fully depressed keys previously prevented from restoration to normal position, the incompletely depressed key remaining depressed so that it may be visually identified, means for preventing redepression of the restored fully depressed keys, and means for preventing actuation of said incompletely depressed key following full depression thereof.

CHRISTOPHER FREDERICK WEBB.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,018,933 Turck Oct. 29, 1935 2,224,203 Turck et al. Dec. 10, 1940

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