US2569508A - Key-operated calculator - Google Patents

Description

Oct 2, 1951 c. F. WEBB 2,569,508

KEY-OPERATED CALCULATOR Oct. 2, 1951 C. F. WEBB KEYAOPERATED CALCULATOR 2 Sheets-Sheet 2 Filed Nov. 22, 1948 INI/smog.

CHRTQPHER FRESEMCK wana Patented Oct. 2, l95l UNI TED S TAT ES PATEN T FFICE 2,569,508 KEY=OPERATED CALCULATOR Christopher Frederick Webb, London, gEngland,

assignor to Bell Punch Company Limited, London, England, a British company Applica-tion November 22, 1948, SerialNo,261,848 Ill-Great B'rihill Decnber 2, 1947 4 Claims, l

This invention relatesto calculating machines and has particular-reference to the type of calculating machine in which the driving rack is normally out of engagement with the registering wheels, for example the type of machine disclosed in my United States Patents No. 2,291,853,- dated August 4, 1942, and No. 2,356,714, dated August 22, 1944, and in my British Patent No.- 522,721, accepted June 25, 1940.

The present invention relates to certain improvements in the type of machine just indicated.

In accordance with the present invention there is provided a calculating machine in which the movement of a key is transmitted through a chain of links -to a rack movable to transmit `motion to a pinion operatively connected to a numeral Wheel, one of the links-of the said chai-n of links being connected to the rack so that any movement of the said link relatively to the rack is solely of a pivotal nature, and being operable through the remaining links of the chain to impart to the said rack, when moving toward or away from its initial position of rest, arelatively slow motion. In brief, the chain of links insures that as the quadrant rack moves from its position of rest it gradually increases its velocity and, when making its return stroke, moves back to its position of rest gradually. vIn their nal movement both the quadrant rack and the pinion-connected to the numeral wheel are brought to rest before the linksrof the chain have ceasedmoving. This arrangement insures that upon the return of thequadrant rack to its initial position any sudden jar is completely eliminated.

Another improvement provided in accordance with the present invention relates to thel provision of means whereby the numeral wheelsare normally locked against rotation and which, when they are about to be set in motion as the result of actuation of a key, are automatically releasedfrom said lock.

Hitherto in calculating machines of the Ycharacter indicated, a pinion wheel associated with the numeral wheel is arranged to engage witha yieldingly controlled pawlwhich, when the pinion is set in motion as the result of actuation of a key, yields` against the motion ofthe pinion so as to permit the same to rotate. It will be appreciated that insuchcircumstances the pinion is not positively locked against rotation, but is merely held in a predetermined position` by a yieldingly controlled pawl engaging with the pinion between'two of its teeth, but in-suchfashion will yield to such movement. Wth'a 'yieldingly' controlled pawl it isnecessaryto have ar driving spring for the pinionr of the numeral wheel much stronger rthan would be the-case if the numeral wheel was ,not controlled by a yieldngly controlled pawl; vAccording to the present invention, ysince the pressure kon the pinion is relieved, a lighter'drivingspri-ng is required and, consequently, the operator need not exertfsuch high pressures upon the keys `as whena yieldingly controlled pawl is used.

In accordance with `thevpresent invention there is associated with each pinionmeans normally locking the same, positively against rotation and which, when a pinionis 4about to beset inmotionlas the resultl of the actuation of a key, automaticallyreleases ythefpinion. Thus the friction inherent in any type of yieldingly controlled pawl is completely ,eliminated enabling -a lighter touch of key operation to be employed.

In my British Patent No. 522,721, referred to above, there 4isdisclosed a calculating machine in which the rack is movable by a key of a bank of keys upwardly and during its upward stroke is maintained` out of engagement with the pinion of the numeral-wheel. When,however, the pinion has reached the position which correspondsto the full actuation of the operated key a trip bar isy movedby the action of the said key to permit the rack,-funder.the influence of -a yielding control. to move intov engagement with the pinionof the-numeral wheel. In that arrangementthe operated key directly engages with abar whichextends longitudinally through each column of the machine and which, upon the actuation of the :key, swings Athe bar in a direction transverse to the normal direction ofathe rack as it moves intoengagement with the pinion soas to `permit'acatch to move downwardly in a slot formed m a1 member connectedto the rack so that the rackisthen free to move under the said yielding control into engagement with the pinion of the numeral wheel. Thus it will be seerr that theca'tch moves1 transversely tor the linek of vmovement 'of the rack lbythe l'inc'ki'ng movement of' thetrip bar actuated by the "key and exact adjustment isrequired lo-synchronis the moment of releasing the" trip' bar by' the key with the arrest' ofthe mechanism, andy ity is'an object of the invention to accomplishht'he release without this .exact relation.y Furthermore, the release of thecatch referred to onlyl takes place at the Avery bottom ofthe key stroke therethat when the numeral Wheelismovedthe pawl 66' by introducingfafrather'harsh-operation, and it 3 is a further object of the invention to eliminate, or at least greatly to reduce, this harshness.

In accordance with the present invention, upon actuation of a key, a trip bar is movable in a longitudinal direction so as to release a catch, and such release is effected directly by the mechanism and only through the medium of the key stem.

The objects of the present invention relate to the attainment of the ends above indicated. These general objects as well as objects relating to details of construction and operation will become apparent from the following description read in conjunction with the accompanying drawings, in which:

Figure 1 illustrates in vertical section the devices associated with one bank of keys of a machine of the type described; and

Figure 2 is a diagram particularly illustrating the actuation of the rack controlling linkage above referred to.

As will be evident from reference to the prior patents mentioned above, the machine is of the general type disclosed therein and there are not herein detailed those elements of the complete machine which are known to the art through the disclosure of said patents, the disclosure being confined to those devices which include the improvements embodying the present inventions.

The bank of keys 2 illustrated in Figure 1 have associated with them a key bar I, the movement of which is transmitted through a chain of links 3, 4, 5, E and 'I to a quadrant rack 8 movable to transmit motion in degree related to the operated key to drive a pinion 9 connected to a numeral wheel I8. The link 1, of the said chain of links, is connected to the quadrant rack 8 so that any relative movement between the quadrant rack 8 and the link I is solely of a pivotal nature. The link 'l irs operable through the remaining links of the chain to impart to the quadrant rack 8 a velocity which increases from zero. The return movement of the quadrant rack 8 to its position of rest is also effected gradually, thus insuring that the quadrant rack 8 is provided, both at the commencement of its movement and at the end thereof, with a relatively slow motion which reduces the inertia of the quadrant rack and the numeral wheel 9 to a minimum and assures the smooth and gradual arrest thereof.

When a key 2 is depressed an abutment thereon engages with the key bar I to move the same downwardly. The key bar l is connected at substantially the ends thereof to a bell crank lever II pivoted at IIa on a fixed transverse pin and to a link 4 which is shaped as a bell crank lever. `lIhe construction is such that as a key is moved downwardly the key bar moves downwardly and inwardly as described in said patents. As the key bar I moves downwardly it imparts through rthe pins of links 3 to 1, inclusive, to the quadrant rack 8 a motion which will be more specifically set out in describing Figure 2. It will be observed that the link 3 is pivotally connected to both the key bar I and the link 4 by pivot pins I2 and I3. The link 4 is pivotally mounted uponl a Xed pin I5 which extends the entire breadth .of the machine, and is common to the various key orders thereof. The end of the link 4, remote from that which is connected to the link 3, is pivotally connected to the link 5 which in turn is pivotally connected to a point intermediate the length of the link 6 which is shaped as a. bell crank lever. The upper end of the link 6 is pivoted upon fixed spindle I5 whichextends through the entire breadth of the machine. The lower end of the link 8 is pivotally connected to the link 'I which in turn is connected through a pivot pin to the quadrant rack 8 so that the only movement of the link 'I relatively to the quadrant rack 8 is a pivotal movement, thereby avoiding any sliding movement oi the pivot in a cam groove as disclosed in Patent No. 2,356,714.

Referring specically to Figure 2, there is diagrammatically illustrated the operation of the chain of links as the key 2a carrying the numeral 9 is depressed to move the quadrant rack 8 from its position of rest through its complete movement of nine teeth. An arm 4a of the link 4 is shown pivotally connected at A1 to a selector bar Il. As the key 2a of the series of keys 2 is operated it moves, through the medium of the bell crank levers II and 4, the selector bar I'I through the positions marked A, B, C, D and E. As the selector bar is moved through these positions the pivot pin of the arm 4a moves through the positions A1, B1, Ci, Di and E1 and the free end of the link 4, shown as pivotally connected at A2 the link 5, moves through the positions A2, B2, C2, D2 and E2, While the end of the link 5 which is shown as pivotally connected at A3 to the link 6 moves through the positions A3, B3, C3, D3 and E3. The movable end of the link 6 is pivotally connected at A4 to the link 'I and moves through the positions A4, B4, C4, D4 and E4 while the link l which is pivotally connected at A5 to the quadrant rack 8 does not move at all during the initial movement of the other links from their A to their "B positions, after which the end of the link 'I which is pivotally connected to the quadrant rack 8 takes up the successive positions C5, D5 and E5. The initial positions A5 and B5 are coincident. As the link 'l moves so that the quadrant rack 8 is moved the successive positions of the first tooth are those indicated at A6, Be, Cs, De and E6, As and Be being coincident.

It will be observed that during the operation of the machine the upward movement of the rack may be arrested by the appropriate key at any tooth position from one to nine, this being controlled by the co-operation of key stems with the bars I and I'I, as disclosed in said prior patents. At any of such positions the connection of the link 'I with the link 6 becomes temporarily a stationary point about which the link l can swing to permit the quadrant rack 8, when released, to move into mesh with its pinion 9. It should further be noted that at any one of the said nine positions the link 'I will insure that the tooth engagement of the quadrant rack 8 with the pinion 9 is in a substantially radial direction relatively to the pinion 8.

It will be observed from the above that upon the initial movement of the key the operator merely sets the cha-in of links which is to operate the quadrant rack 8 into motion, without effecting any movement of the rack 8 itself, after which the quadrant rack 8 is moved to an accelerated degree. Referring to Figure 1 it will be observed that the main spring I8 is anchored to a lateral extension 4b of the link 4, the arrangement being such that shortly after the movement of the link has commenced the anchorage point of the extension 4b of the link 4 rises so as to cause the effective leverage of the tension spring I8 about the pivot A1 to diminish as the tension of the spring I8 increases. The arrangement of the link 4 and extension 4b thereof is designed to produce a substantially constant resistance to the pressure *of `r`the operators ng'er throughout 'an operating stroke. If the yconnection between the link 'I and the quadrant rack is cfa purely pivotal lcharacter, friction is minimised Lascentrasted with that involved in a sliding -pin -a-nd j slot.

Upon the completion of akey'stroke the Vquad'- rant rack A8 is released by the trip mechanism -as hereinafter described and is moved under the iniluence of the drivingspring AI8 intoen'gagem'ent with the pinion 9, this being effected through the pivotal connection `of the rack to the lever 1|9 to which the rear end 1of the spring -issecured v -As Tthe lquadrant rack returns to its y'positio'r-ifofrest under the iniiuence of the -spring A)I8 `and itl-1ere- 'fore returns the pinion y9 `and the numeral wheel l0 to their positions 'of -rest it arrives at such -a position of rest before the chain of lin-ks formi-ng the operative connection between the vquadrant rack and the key bar have ceased moving, Consequenty, it is insured that the numeral `wheel I0 and its pinion 9 are stationary before the -mechanism effecting the withdrawal of the rack from the pinion -9 is brought into operation.

Associated with each pinion 9 there isa pawl 2| and locking lever 22. This arrangement ynormally locks the pinion 9 against rotation, and an arrangement is provided which, when-a'pinion 9 of a bank of keys is about to beset in motion as the result of actuation of ya key, automatically releases the pinion. The pinions 9 are released either when the rack 8 positively moves the pinion or when a transfer mechanism 23 rotates through the mediumfof pins 23a a toothed Wheel 24 connected to the pinion 9. This transfer mechanism is disclosed -in Patent No. 2,291,853, and need not be described in detail except to the extent of reference to the pins 23a.

First, dealing with the instance Where the pinion '9 is moved by the rack 8 it will be evident that when the trip mechanism described hereafter releases the rack 8 the lever 22 is moved in a counterclockwise direction about its pivot-21 by the flexing of a spring 28 connected between it and the lever I9. By this-action the lever v22 is moved downwardly and out of engagement with the locking surface 29 with which it normally engages. The pawl 2| released from its positive locking engagement with the pinion 9 permits the numeral wheel to be freely rotated. Due to the fact that the pawl 2| is not of a yieldingly controlled type which snaps into and out of engagement with the tooth of the pinion 9 the operation of the numeral wheel is rendered less noisy than in the case of a pinion wheel which is restrained by a yieldingly controlled pawl.

When -a numeral Wheel of a lower order is transferring to a numeral wheel of a higher order the pins 23a are arranged to engage with the right hand lateral extension 22a of the locking lever 22 to swing the same in a clockwise direction about its pivot 21 so as to move the locking lever out of engagement with the locking surface of the pawl 2 I. After the transfer action has taken place the pawl again becomes locked in the position indicated, this being insured by contact of pin 23a with the left hand extension 22a of the locking lever.

It has been shown that the numeral pinions are yalways positively locked except when an adding or transferring operation is in progress, but it will be appreciated that it is also necessary to remove any obstruction from the path of the pinions during a cancelling operation in order to permit the numeral wheels to be returned to fzero. For this vpurpose there-may be 4provided ymeans for `displacing .by Amanual operation of .a 'cancel lever all of the pawls 2| in the vaxial di- 'rectionof the pinions 9 so that the pawls 2| are temporarily moved yout of the path of the vpinions '9 Without in kany Way interfering with the locking functions already described. A spring v2|at is arranged to exert a slight torque on the pawl 2| 'inan axial direction to return the tip of the pawl :into theplane of the pinion following a cancelling operation.

It will be seen that according to the present invention there is provided a calculating machine inwhioh the pinions ofthe numeral wheels are normally locked positively against rotation, and `wherein the arrangement is such that when the pinion wheels :are about to be set in motion the positive lock isreleased and the pinion Wheels are free to be rotated eliminating all friction and en- :abling a lighter key touch to be employed in View "of `the fact that the driving spring YI8 need not vbe as strong as would be the case if a yieldingly controlled pawl was employed.

After the rack 8 has moved free of the pinion tothe degree determined by the key which has been operated, it mustbe permitted to engage the pinion and this action is effected upon full depression of the key. The lower end of a key stem, when it reaches the position indicated in dotted lines `at 2b, is yadjacent one of the projecting lugs 32 formed on a trip bar 33. When .the key stem reaches the dotted -position a tooth of the bar will have reached the face of the key at 2b and at the same time, a groove 2c formed small amount, whereby the lug 32 and the trip bar 33 are moved from right to left as viewed in Figure l. This movement of the trip bar 33 swings catch lever 34 pivotally mounted at 35 about this mount so as to move the end 33 thereof out of engagement with a tongue 31 carried by :the lever |9 which at pivot point 3| is connected `to the rack 8. When the catch lever 34 is released from the tongue 3l the spring I8 urges the rack in a direction toward the pinion 9 of the numeral wheel lll.

It will be noted that the lever I9 is released by the roller 20 on the bar when a key is depressed, and that this same roller effects disengagement of the rack 8 from the pinion 9 by its action on the lever I9 when a key is released to its uppermost position.

Thus it will be seen that the movement oi the bar of the mechanism, in response to the depression of a key, causes the release of catch 36 Without direct vertical contact of the end of the key stern as formerly required, and in ordinary operation the trip is effected by the momentum of the mechanism without direct influence from the key. Such an arrangement practically eliminates that harshness introduced by the dead end stroke operation inherent in the arrangement described in said British Patent No. 522,721.

What I claim and desire to protect by Letters Patent is:

1. In a calculating machine of the type referred to having a plurality of keys, a member movable to an extent variable in dependence upon the key actuated, a rack, a pinion adapted to be driven by said rack, a numeral wheel connected to said pinion, and a linkage connecting said member and said rack to drive the rack.

'said linkage including a pair of links, one end of each of the links being pivotally joined together, the opposite end of one of the links of the pair being pivoted to said rack, the opposite end of the second link of the pair being pivoted about a nxed point, and the second link of the pair being actuated by an adjoining portion of the linkage connected to said member, the link-age being constructed and arranged to impart to the rack a relatively slow motion when the rack is moving towards or away from its position of rest.

2. In a calculating machine of the type referred to having a plurality of keys, a member movable to an extent variable in dependence upon the key actuated, a rack, a pinion adapted to be driven by said rack, a numeral wheel connected to said pinion, and a linkage connecting said member and said rack to drive the rack, said linkage including a pair of links, one end of each of the links being pivotally joined together and the opposite end of one of the links of the pair being pivoted to said rack and the opposite end of the second link of the pair being pivoted about a xed point, and a link joining said member to the second link of the pair, the linkage being constructed and arranged to impart to the rack a relatively slow motion when the rack is moving towards or away from its position of rest.

3. In a calculating machine of the type referred to having a plurality of keys, a member movable to an extent variable in dependence upon the key actuated, a rack, a pinion adapted to be driven by said rack, a numeral wheel connected to said pinion, and a linkage connecting said member and said rack to drive the rack, said linkage including a pair of links, one end of each of the links being pivotally joined together, the opposite end of one of the links of the pair being pivoted to said rack, the opposite end of the second link of the pair being pivoted about a fixed point and the second link of the pair being actuated by an adjoining portion of the linkage connected to said member, the linkage being constructed and arranged to impart to the rack a relatively slow motion when the rack is moving towards or away from its position of rest, said linkage including a pivotally mounted membei' and a spring for driving said rack connected to said pivotally mounted member, the connection being such that as the pivotally mounted member rotates about its pivot the eiective leverage distance of the spring from the pivot decreases as the spring tension increases so as to oier substantially constant resistance to the pressure of the operators finger in actuating a key.y

4. In a calculating machine of the type referred to having a plurality of keys, a member movable to an extent variable in dependence upon the key actuated, a rack, a pinion adapted to be driven by said rack, a numeral wheel connected to said pinion, and a linkage connecting said member and said rack to drive the rack, said linkage including a pair of links, one end of each of the links being pivotally joined together, the opposite end of one of the links of vthe pair being pivoted to said rack, the opposite REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,301,073 Mays Apr. 15, 1919 1,417,924 Koronski May 30, 1922 1,637,827 Kottmann Aug. 2, 1927 1,700,057 Johnson Jan. 22, 1929 1,761,431 Degener June 3, 1930 1,983,945 Petter Dec. 1i, 1934 2,033,087 Avery Mar. 3, 1936 2,356,714 Webb Aug. 22, 1944

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