US1938168A - Printing mechanism for calculating machines - Google Patents

Description

Dec. 5, 1933. w. BALI.

PRINTING MEICIIANISM` FOR CALCULATING MACHINES Original Filed May 31, 1950 '7 Sheets-Sheet l fm A0/...f a Hf v A nH W aw. 9,. w 1 A a0 7 FIM V Dec.. 5, 1933.

W. BALL PRINTINGRMECHANISM FOR CALCULATING MACHINES Original Filed May 31, 1950 7 Sheets-Sheet- 2 K n.. img EE .T v .f mw. A ./7 E E Dr Dec. 5, 1933. W. BALL PRINTING MEcHANIsM FOR CALCULATING MACHINES Original Filed May 31, 1930 7 Sheets-Sheet 3 Dec. 5 1933. W, BALL k1,938,168

PRINTING MECHANISM FOR CALCULATING MACHINES Original Filed May 5l, 1930 7 Sheets-Sheet 4 INvEurUEI W. EAU..

ATTQRNEY Dec. 5, 1933. w.l BALL 1,938,168

PRINTING MECHANISM FOR CALCULATING MACHINES original ggggwmay 51, i950 v sheets-sheet 5 Inward-rum? Dec. 5, 1933. w. BALL PRINTING M-KECHANISM FOR CALCULATING MACHINES Original Filed May 5l, 1930 7 Sheets-Sheet 6 Y w. .m .KL/WM Hu T..- T NA T WE A mw/f .f E E D.

Dec. 5, 1933. -w. BALL PRINTING MECHANISM FOR CALCULATING MACHINES Original Filed May 31, 1930 7 Sheets-Sheet '7 lNveNTOE W BALI..

PEE ATTORNEY Patented Dec. 5, 1933 U TES NITED STA PRINTING MECHANISM FOR CALCULATING MACHINES William Ball, Wallington, England, assignor, by direct and mesne assignments, to "British Adding and Calculating Machines England Original Limited, London,

application May 131, 1930, Serial No.

458,629, and in Great Britain August 14, 1929. Divided and this application August 13, 1931.

serial No. 556,888

` 14 claims.

This invention relates to printing'mechanism and more' particularly to printing mechanism for use in calculating or like machines. The invention is a division from application Serial No. 458,629 led 31st May 1930.

Printing mechanism for such machines has hitherto embodied hammers which strike the type bars with percussive effect, or the type bars themselves have been arranged so that normally they are retained against pressure from, for example, springs, and after setting are suddenly released so that the pressure imposed on the type bars causes them to strike the platen with an impulsive blow.

Such printing mechanism as above described has the disadvantage that considerable noise is engendered each time the platen is struck, and, furthermore, wear on the machine is usually great. l

In order to overcome the effects produced by percussive or impulsive printing, it has also been proposed to provide mechanism operatively connected with'the main shaft of the machine which mechanism moves therewith and by its movement appliespressure to the type bars. With this arrangement, however, the type bars are not pressure loaded for printing so that pressure for printing depends wholly on the nature or construction of the connections with the main shaft.

The mainA object of the linvention is to provide a simple and eicient printing mechanism in which percussive printing is avoided and yet denite pressure is applied to the type bars for printing and correct alignment of the type is obtained, and in which the number of working parts is reduced, and, furthermore, such parts rendered simple and cheap to produce, easy to assemble, and durable in operation.

Another object of the invention is to provide improved means for operating the type bars to cause the same to print and a further object is to provide an improved construction of type bar in the production of which the number of working operations is reduced.

One feature of the invention, therefore, relates to printing mechanism for a calculating or like machine, comprising in combination settable type bars and pressure storing means arranged to be gradually released so as to exert a gradually increasing pressure on the type bars for causing the Vsame to print, whereby the necessity for percussive printing is avoided and noise and wear greatly reduced.

According to another feature of the invention, a calculating machine including denominational totalizer wheels and settable spring controlled type bars for printing the setting of the totalizer Wheels is provided with means normally maintaining the type bars in a non-print position and operable by movement of the main shaft subsequent to the setting of the type bars to gradually release the latter for printing under the spring action, whereby definite and requisite pressure may be obtained for printing while avoiding the necessity for percussive printing.

Preferably each type bar, according to the invention, is provided with a spring controlled pressure device, which is gradually releasable to exert gradual pressure from its springs on the associated type bar for moving the latter to printing position, such pressure device also preferably including aligning means type bar to initially align the latter prior to its being moved to printing position.

The invention will be 4further described with reference to the accompanying drawings which illustrate by Way of example the application of the invention to a form of calculating machine shown and described in the parent case above referred to, only those gures being shown which are deemed necessary for a complete understanding of the invention. It should be understood, however, that the invention is in no way limited to this particular type of machine, but can be easily adapted for use with other forms of calculating machines.

In the drawings,

Fig. 1 is a general plan of the machine showing the unitary structure thereof.

Fig. 2 is a vertical'section on the line Il-II of Fig. 1; y Fig. 3 is a sectional plan taken on the line III-, III of Fig. 2;

Fig. 4 is a sectional elevation looking from the rear taken on the line IV-IV of Figs. 1 and 2;

Fig. 5 is a view from the left of a calculating unit detached, the column showin-g nine numeral keys in addition to the column release key at the extreme right hand end and corresponding to one of the pounds columns in the machine in the preceding figures;

Fig. 6 is a detail section of the side plate carrying the non-print, non-add, repeat and error keys land their associated mechanism, which plate is preferably located at the right of the machine;

Fig. 7 is a perspective constructional view of a single type bar and its associated pressure printing and non-print devices looking from the left of Fig. 4;

for co-operating with the Fig. 8 is a detail perspective view of a nonprint device from the right of Fig. 4; and

Fig. 9 is a diagrammatic view showing the operated and non-operated positions of a nonprint device.

Although the machine is readily adaptable to power operation, the preferred form illustrated has been shown as hand operated.

'Ihe reference numerals used herein correspond with those employed for similar parts in the parent case.

The complete operation of the calculating machine disclosed by the accompanying drawings is described in the parent case; it will be sunicient to explain briefly the fundamental mechanism with which the printing mechanism according to this invention co-operates in order to obtain a setting of the type bars corresponding to the amount of the item entered on the keyboard.

'I'he machine is built up by assembling a number of detachable calculating units 12-one of which is shown detached in Fig. 5-on bearer rods 10 and 11 mounted between side frames 3, each unit consisting of a base plate, hereinafter termed a stretcher plate, having open housings 13 and 14 for removably engaging with the rods 10 and 11. Each unit 12 has a key column comprising a series of numeral keys 32 and a column release key 32a, so that when the units are assembled a sectionalized keyboard as shown in Fig. 1 is produced.

'Ihe respective units 12, in addition to the key column, also carry a totalizer wheel 20 and differentially geared actuating and setting mechanism for setting the totalizer wheel 20 in accordance with the value of a key 32 which may be depressed in the associated column. This mechanism, as will be seen from Fig. 5, consists of an actuating rack 56, pivotally connected at 55a to a linearly movable pinion 55 gearing with an upper rack 53 carrying a setting rack 58, and with a lower transfer rack 57 normally held stationary by a pin ,101 on the transfer lever 94, the pinion 55 being connected to and moved by a rocker 70 actuated by springs 64 and 64a under the control of the main shaft 1, which is mounted between the side frames 3.

Control of the various rockers 70 is eiected by arms 74 on the main shaft 1, which respectively are disconnectably engaged with a roller 73 on the end of an arm 72 forming part of the associated rocker, so that as the main shaft 1 is rotated in the direction of the arrow Fig. 5, the rockers 70 are also permitted to rotate anticlockwise under the action of the springs 64 and 64a, provided each has been released by depression of a numeral key 32 in the associated column, which depression causes the column release key 32a to spring upwards out of engagement with the rst abutment 63 on the setting rack 58, whereupon the upper rack and therefore the rocker 70 is free to move.

This operation is clearly described in the parent case and in a divisional application therefrom numbered 556,834 filed 13th August 1931.

The top rack 53 moves twice as fast as the actuating rack 56, so that the setting rack 53- by reason of its end engaging in the inclined slot 61 in the actuating rack-is caused to rise towards the keys as well as to move longitudinally thereunder, until one of the abutments 63 of which there is one to every key in the column, comes into engagement with the corresponding key which has been depressed, thus stopping the movement of the associated rocker 70.

If the totalizer wheel 20 is engaged with the actuating rack 56 during this movement, it will be set or turned an amount corresponding to the value of the key depressed; similarly, if the totalizer wheel 20 is engaged with the actuating rack when this is moved to its normal position, as will be the case when the rotation of the main shaft 1 is reversed, the wheel 20 will be turned in the opposite direction for the same amount.

The totalizer engagement operations are clearly described in the parent case.

Pivoted at to each stretcher plate 28 is a type bar controlling lever 84 with which a roller 83 on another arm 82 of the associated rocker 70 co-operates under the action of a tension' spring 249, the lever 84 being connected to a type bar 240 by means of a pin 241 on the bar 240 engaging in an open-ended slot 242 on the lever 84, this construction facilitating detachment of the associated unit from the machine. 'I'he type bar 240 has a flat face around which is gripped the sides 245 of a type block 246,`the type of which corresponds to the numbers of the numeral keys in the associated column, and it will be clearly understood from the above description that when the actuating rack 56 of each unit is moved to the left on the forward stroke of the main shaft 1, an amount corresponding to the key depressed in the associated column, the associated type bar 240 will also move longitudinally upwardly for an amount to place` the correct type opposite to the printing line on the platen roller 243. After the type bars have been set they require to be moved towards the platen for printing, this movement according to the invention being controlled from the main shaft l through a printing link 202, see Figs. 2 and 6, which draws arms 203-between which a bail 261 is mounted for controlling the printing section according to this invention hereinafter described-forwardly by reason of a slot 204 in the end of the said link 202 engaging a pin 205 at the end of one of said arms 203. The arms 203 are mounted on a shaft 260.

The slot 204 closely fits the pin 205 in its lower area, which is normally occupied by the pin 205 by reason of a spring 206 which maintains the link 202 in its upper position.

Control of the link 202 is effected by a spring controlled non-print key 201 which depends through the top plate 161 and through a guide plate 207 bent over from the sub-frame 162 and under the top plate 161 and carries a pin 208, preferably with an anti-friction roller which engages an arm 209 of a virtual bell crank 210 it being understood that the arm 209 is at the right of the machine, while the bell crank arm 210 is at the left of the machine, the two being connected and fixed to a transverse shaft 211.

212 is a roller provided on the end of the bell crank 210, which when the bell crank 210 is rocked by depression of the non-print key 201, co-operates with a cam face 213 on the link 202 so as to force the latter downwardly whereupon the pin 205 occupies the enlarged portion of the slot 204, and operation of the handle in this event does not effect printing.

The key 201 is held depressed by a notch 201a in its shank engaging the top plate of the sub frame 162.

As will be seen more clearly from Figures 1 and 4, the series of type bars 240 are arranged in compact relation at the rear of the machine, so that a series of figures set up in the keyboard may be printed on paper carried by the platen roller 243 in columnrelation, the levers 84 of the various outer units being bent inwardly see Fig. 3 to connect with the lower ends of the type bars 240.

In order to avoid the wear produced by percussive striking hammers and further to eliminate the consequent noise by the usel of such hammers, the printing action embodies means for effecting a gradual application of`pressure on the type bars, the movement of the handle subsequent to the setting of the type bars being effective to allow such gradual application of pressure, and the arrangement being such that normally the type bars are maintained in a nonprint position and towards the end of the forward stroke of the handle, after they have been set, a spring controlled pressure device is allowed to gradually act on the type bars as the handle continues to the end of its forward stroke to thus eiect the printing.

As shown in the drawings, with more especial reference to Figures 2, 4, 7, 8 and 9, associated with each type bar 240 is a spring controlledv pressure device, preferably embodying also means for aligning the type prior to printing and comprising a bell crank 251 and a rockable member both pivotally mounted on a common transverse shaft 252 carried by the main side frames 3 of the machine.

The rockable member, as shown, consists of a iiexible lever constituted by two arms 248 and 248C, pivotally connected at 248e, the arm 248 being pivotally mounted on the transverse shaft 252 'and connected at its lower end 248a to a tension spring265 fixed to the cross shaft 260, while the arm 248e is pivotally connected at 248D to the bell crank 251 and is provided with a pin 247 which rides in a guide slot 240a in the type bar 240. Preferably, the rear face of each type bar 240 is provided with serrations or teeth 253, while the associated bell crank 251 is provided at its top end with an outstanding pin 250 preferably having an anti-friction roller 254 for engaging with the serrations 253 of the type bar 240Y to align the latter' after setting and prior to printing and apply pressure to the type bar by means of a tension spring 255 connecting the lower end 25la of each bell crank 251 with the shaft 260, Vthe pressure of the spring 255 also being augmented by the tension of the spring 265 as will be explained hereinafter.

The pitch of the serrations or teeth 253 correspondl with the spacing of the type, and by reason of the pins 250 or their rollers 254, engaging the serrations the setting of the various type bars is effected positively so that the correct type comes opposite to the printing line.

As will be seen from Figure 1, the heads of the type bars 240 project upwardly through an aperture 21 in the cover 17 and on a keyboard setting being made and the operating hand 4 rotated.. the various rockers rotate in a counter clockwise (seeFig. 2) direction as far as is permitted by the particular key setting for each column. the levers 84 associated with and controlling the setting of the printing section following the rollers 83 on the rockers 70 byreason of the springs 249, and each type bar is thus raised to a distance corresponding to the key setting ln the particular column with which the type bar is associated.

For instance, supposing the 0 or column release key of a column be depressed, no move- 246 would remain with the ment of the actuating mechanism and therefor of the rocker 70 to follow the operation of the handle 4 would occur and thus there would be no movement of the type bar 240 and the type 0 opposite the printing line of the platen roller 243.

Should the nine key of any particular column have been depressed, operation of the handle 4 would cause. the actuating mechanism and therefore the rocker '70 to move to its full extent, so that the lever 84 of this particular column would cause its type bar 240 to rise to its full extent and place the 9 type on the printing line.

It will be noticed that, when the type bars 250 are in the 0 position, the top ends of the guide slots 240a form a limiting stop and further, when the type bars have been moved from normal position, they are returned to their 0 position by virtue of the rollers 83 abutting against the cam faces on the right ends of the bell cranks 84 of the printing section during the return stroke of the handle 4 so that the type bars are restored against the tension of the controlling springs 249.

Printing is arranged to take place almost at the end of the initial stroke of the handle 4, except when the non-print key 201 is depressed and is controlled by the transverse bail 261, carried by the pair of pivotal levers 203, operable from the main shaft 1, through the printing link 202 hereinbefore described.

The pivotal lever 203 is shown extended below its pivot point 260 preferably at both sides of the machine, and is connected to a tension spring 20341. xed to the frame 3.

The transverse bail 261 normally engages the lower ends of both the bell cranks 251 and the levers 248, so as to maintain the pressure devices in a non-print position as shown inthe drawings, against the tension of the springs 255 'and 265, in which position the type bars 240 are not pressed into contact with the paper carried by the roller 243.

The link 202 see Fig. 6 is connected to the operi ating shaft 1 by a pin and slot device constituted` by an` arm 262 keyed to the shaft 1, the free end of which arm carries a pin 263 riding in a slot 264, having a suitable radius, in said link 202. During the initial movement of the operating handle 4 in the direction of arrow A in Figure 2, the pin 263rst rides the slot 264 and towards the end of the forward stroke, i. e. `subsequent to the movement necessary to effect the maximum setting of the type bars, abuts with the end 264a of the slot, thereby causing the link 202 to move to the right with the continued movement of the handle and in so doing gradually Vmoves the bail 26'1 to the right against the tension in the springs 203a.

The springs 203a normally tend to keep the bail 261 abutting the lower ends 248g, and 25la of the levers 248 and bell cranks 251 respectively until the pin 263 engages with the end 2640, of the slot 264.

Assuming that the mechanism generally designated 270 has been operated, as will be described hereafter, as the bail 261 moves to the causes the aligning rollers 254 thereon to move towards the type bars 240 whilethe rocking of the levers 248 causes the associated levers 248e to pivot about the pivot points 248b on the bell cranks 251 and thereby move the type bars relatively towards the aligning rollers 254 until the latter engage with the serrations 253 corresponding to the setting o f the type bars. This relative movement may be assisted by the springs 244 connecting the top ends of the bell cranks 251 with the levers 248e.

Consequent upon the aligning rollers 254 engagingy with the serrations 253, the levers 248 and 248C of each pressure device then move as one so that subsequent to their alignment the type bars 240 are moved towards the roller 243 for printing under the combined influence of the springs 255 and 265. Thus, during the movement of the handle 4, subsequent. to the setting of the type bars 240, the bail 261 is effective to gradually release the pressure devices to simultaneously align the type bars prior to printing and subsequently move the latter to printing position so that the item set up in the keyboard is printed on the paper carried by the roller 243.

Upon the return stroke of the handle 4, movement of the arm 262 to the left (see Fig. 2) allows the springs 20311 to act on the pivotal levers 203 so that the bail 261 is caused to abut against the lower ends 248:1,l and 251a of the pressure devices and thereby rock the levers 248 and the bell cranks 251 in a clockwise direction to disengage the aligning rollers 254 from the serrations 253 of the type bars 240. The type bars are thus allowed to be restored to their normal position against the tension of the springs 249, during the return stroke, by the rollers 83 on the arms 82 of the rocker 70 abutting against the cam surfaces on the right hand ends of the levers 84.

At such time as the non-print key 201 is depressed the bell crank lever 210 actuates the printing link 202 so as to bring the lost motion slot 204 over the pin 205, and in this event, as will be seen, forward movement of the operating shaft 1, is not transmitted to the levers 203, whereby the bell cranks 251 and the levers 248 are not permitted to rock under the influence of theirsprings 255 and 265, so that although the various type bars are set the pressure devices are rendered ineffective and no printing takes place.

Immediately the non-print key 201 is released, however, the printing link 202 assumes its normal position as shown in Figures 2 and 6 under the action of the spring 206, so that subsequent forward movement of the operating handle 4 is elective to gradually release the pressure devices for causing the type bars to print.

The signs printed by the machine are clearly shown in Fig. 4, four type bars only corresponding to the farthings, pence and shillings columns being shown on the left of the figure, and on the right a single type bar 300 is shown on which the signs corresponding to the non-add key 200, the subtraction key 146 and the total and subtotal keys 230 and 231 respectively are mounted. The operation of these keys is clearly described in the parent case.

'I'he mechanism generally designated 270 provided to prevent the printing of ciphers tothe left of the highest denominational digit set up in the keyboard will now be described hereafter, with reference more particularly to Figs. 2, 4, 7, 8 and 9.

Each side frame 3 is arranged towards its rear end with three main bushings, which carry respectively a transverse shaft 307 carrying the noprint pawls 270, a common transverse shaft 252 for the bell cranks 251 and levers 248, of the pressure devices oi.' the printing section, and the transverse shaft 260 on which are mounted the arms 203 carrying the printing bail 261, which engages under the lower ends 2510. and 248a of the bell cranks 251 and the levers 248 respectively.

Each lower end 251a is provided with an upstanding lug 308 having a jaw 309, under which a tongue 310 on the no-print pawl 270 of that particular denomination is positioned when in normal position.

The pawl 270 has a cranked portion 311 connected by a spring 312 to a stop member 313 pivotally mounted on the shaft 307, and as seen from the rear ofthe machine the left face of the stop member 313 abutting against the right face of the type bar 240 in its normal position and the end of the stop 313 engaging therlower outstanding extremity 245a of the type` block 246.

As will be seen more particularly in Figures 7 to 9 the spring 312 is normally in tension and is connected at one end to the lower right hand extremity of the stop member 313 and at the other end to the top end of the cranked portion 311,01 the pawl 270. t

The cranked portion 311 of the pawl 270 is provided with a lip 314 which lies over the upper edge of the stop 313 with a small clearance 314a in the normal position.

l In the normal position of the printing mechanism las shown in the figures referred to, it will be seen that the spring 312 is tending to draw the tongue 310 into abutment with the lug 308, but upon the type bar 240 being moved upwardly to its setting the consequent vdisengagement of the outstanding extremity 245a of the type 245 from the end of the stop 313 is eiective to allow the tension in the spring 312 to rotate the stop 313 about the shaft 307 in an upward direction. As the stop 313 rotates it comes into abutment with the lip 314 and consequently gives a corresponding rotation to the pawl 270 to withdraw the tongue 310 from the jaw 309. v

To assist this action a spring 270g connected between the pawl 270 and the main frame may be provided. The normal and operative positions of the pawl and stop are shown in Figure 9 by full and dotted lines respectively, and from which the action of the springs 312 and 270a will be readly understood.

It will be understood that the radial movement of the end of the stop 313 will be limited such that when the associated type bar 240 is restored the extremity 245a of the type 246 comes into abutment therewith to rotate the stop 313 in a reverse direction so that the tension is restored to` the spring 312 and the pawl 270 caused to follow the rotation of the stop 313.

Thus, it will be seen that immediately any type bar 240 is raised from the 0 position, the associated pawl 270 is cleared from the lug 308 of the bell crank 251, whereby the pressure device of the type bar may be eiective to cause the latter to print as previously explained.

Should, however, the 0 or column release key oi.' a particular unit 12 be depressed, whereat the respective key bar 240 is not kraised during the movement ofthe handle 4, the respective bell crank 251 is prevented from operating by the noprint pawl 270 engaging the .jaw 309 of the projection 308 thereof and thus the type bar is not moved towards the roller 243 for printing.

In this manner printing of any ciphers to the left of the highest denominational digit set up in the keyboard is prevented, but in order that after a setting of a digit in any denomination, the lower denominational type bars 240 shall be effective, i. e. shall print even when no digit has been set up therein, each of the pawls 270 is provided with an angularly projecting lug 315, which engages the recessed face 316 of the next lower denominational pawl 270, the recess being provided by a corresponding projecting lug 315 on vthat pawl which engages the next lower pawl, and so on.

By this means it will be seen that on any particular no-print pawl 270 being freed, the no-print pawls 270 of all lower denominations are actuated by reason of the projecting lugs 315, andthe corresponding type bars 240 are freed for printing.

It will be noted that in the case of the type bars of the lower denomination which have not been set as explained above, and are therefore with the 0 opposite the printing line on the roller 243, the stop members 313 will be in abutment with the extremities 245:1 of the associated type 246 so that no rotation of the stop member 313 will occur, the pawls 270 only being rotated by the lugs 315 engaging with the recesses 316 and the associated type bar 240 being free to move to printing position by reason of the fact that the stops 313 only engage with the side face of the type bars.

While being particularly effective in operation, the construction disclosed enables the type bars 240, the no-print pawls 270 and the stops 313 to be cheaply constructed from sheet metal, the tongue 310, the lip 314 and the projecting lugs 315 being simply stamped out from the body of the pawl 270 and the flanges to take the spring 312 being similarly formed whereby the construction and assembly of the listing portion of the machine may be readily effected.

The preferred construction of cover 17 for the machine is illustrated in Figures 1 and 2, and to enable standard end pressings of sheet metal to be employed for machines of different capacities, the cover 17 is formed from interlocking sections, the two side sections '350 vand 351, see Fig. 1, being standard constructions, and the centre pieces 352 and 353 being dimensioned to suit the various widths of keyboard required. A housing such as 354 may be provided on the section 353 to partially house the printing action and improve the appearance of the machine.

The paper platen or roller 243 can conveniently be arranged in a separate structure 355 arranged for ready securement to the centre section 353 of the cover as shown more particularly in Figs. 1 and 2, and such structure 355 conveniently carries a paper roll 370.

The paper feed is operated from the printing bail 261, a bell crank 371 pivoted on the axis 307 having a forked end 372 straddling said bail so as to oscillate therewith, and a pin 373 at the other end of said bell crank being engaged by the forked end 374 of the depending lever 375 pivoted on a boss 376 of the shaft 377 carrying the platen 243.

The boss 376 may be integral with the feed ratchet 378, into the teeth of which the paper feed pawl 379 pivotally mounted on the drop lever 375 is urged by spring 380.

The drop lever 375 conveniently depends through a slot in the casing 353 and the forked end 374 enables the platen carrying structure 355 to be readily detached.

With this arrangement the rearward or printing stroke of the bail 261 causes the paper feed pawl 379 to escape over the teeth of the feed ratchet' 378, while the return movement of the bail 261 after printing has taken place rocks the bell crank 371 and causes the paper feed pawl 379 to propel the ratchet 378 one tooth, which feeds the platen 243 one step forward, the teeth on the ratchet 378 being of a pitch corresponding to the feed required for the paper.

Accuracy of the paper feed is ensured by a locating roller 381 carried by an arm 382 on the casing 355 and maintained in engagement with the ratchet teeth by a spring 382a, this roller also preventing any unwanted backward movement of the platen 243.

383 is an upstanding writing plate and paper guide shown formed integral with the paper guides 384 and 385 and pressing the side plates of the structure 355 transversely, a serrated transverse edge 386 being conveniently-provided to facilitate tearing off of the paper when desired.

Resistance to the platenmovement and engagement of the paper by the platen is ensured by a pair of rollers 387 and 388 carried by the bail 389 mounted between a pair of bell cranks 390 and urged by a spring 391 so that the rollers 387 and 388 bear on the paper.

The bell cranks 390 are keyed to a transverse shaft 392 and carry thumb plates 393, one at each side, pressure on either thumb plate overcoming the tension of the spring 391 so as to free the paper.

A preferred form of ribbon feed and ribbon reverse are also shown in Figs. 1 and 2, the spools 356 carrying toothed discs 395 for engagement with worms 396 mounted on the platen shaft 377.

397 is a plate secured to the underside of the casing 353, said plate carrying a pair lof pivots 398 and 399 for a pair of three-armed levers 400 and 401. On one arm of the lever 400 an upwardly projecting pin 402 is provided for carrying the left-hand spool 356 while on the corresponding arm of the lever 401 a pin 403 is provided for carrying the right-hand spool, the pins 402 and 403 projecting upwardly through radial slots in the casing 353.

404 and 405 are ribbon guiding pins provided on the plate 397 and projecting upwardly through the casing 353 while 406 and 407 are similar pins but mounted respectively on the second arms of the levers 400 and 401. The third arms of said levers carry pins 408 and 409 engaging a rocker 410 which is provided with a pair of locating recesses 411 engaged by'a spring pressed pin 412.

In the position shown the ribbon is being fed from the right-hand spool to the left-hand spool 356, its tooth disc 395 being in engagement with its worm 396 so that rotation of the platen shaft 377 effecting the paper feed also effects movement of the ribbon.

As soon as the ribbon on the right-hand spool 356 is exhausted, however, the tension in the ribbon actuates the pin 407 to rock the lever 401 about its pivot 399 which actuating through the rocker 410 also swings the lever 400 so that the right-hand spool 356 is thrown into engagement with its worm 396 and the left-hand spool 356 simultaneously disengaged, whereby the'ribbon is 145 reversed.

Projections on the housing 354 may shroud the spools 356 or separate domes may be provided.

The complete construction and operation of the calculatingamachine with which the printing mechanism according to the invention is associated, will be found in the parent case, but

it will `be seen from the foregoing that the employment of printing mechanism according to the invention which is arrangedso that, when operative, it applies pressure from itself gradually on the type bars to effect printing, avoids the necessity for percussive printing while giving definite and requisite pressure to obtain a clear record, and, furthermore, reduces noise and wear to a minimum in a very simple and effective manner.

It will be understood that modifications in the constructional details and also in the manner of carrying the invention into effect will be apparent to those skilled in the art, without in any way departing from the scope of the appended claims. y

What I claim is:-

1. Printing mechanism for a calculating machine comprising in combination settable type bars, a spring controlled pressure device to each type bar for moving the type bars to print, and means for gradually releasing said pressure devices so that the said devices exert a gradually increasing pressure from their springs on said type bars for causing the same to print.

2. Printing mechanism for a calculating machine comprising in combination settable type bars, a spring controlled pressure device to each type bar for moving the type bars to print, means for gradually releasing said pressure devices so that the said devices exert a gradually increasing pressure from their springs on said type bars for causing the same to print, and meansl for aligning the type bar prior to printing.

3. Printing mechanism for a calculating machine comprising in combination settable type bars, a spring controlled pressure device to each type bar for moving the type bars to print, means for gradually releasing said pressure devices so that the said devices exert a gradually increasing pressure from their springs on said type bars for causing the same to print, and means individual to each pressure device for aligning the type bars prior to printing.

4. Printing mechanism for a calculating machine comprising in combination settable type bars, pressure storing means for moving the type bars to print, means for gradually releasing said pressure storing means to exert a gradually increasing pressure on said type bars for causing the same to print, and means for preventing predetermined type bars being moved to printing position.

5. Printing mechanism for. a calculating machine comprising in combination settable type bars, a spring controlled pressure device to each type bar for moving the type bars to print, means for gradually releasing said pressure devices so -that the said devices exert a gradually increasing pressure from their springs on said type bars for causing the same to print, and means individual to each pressure device for rendering said pressure device inoperative to cause its type bar to print when said pressure device is released.

6. Printing mechanism for a calculating machine comprising in combination settable type bars, a transverse shaft, a bell crank to each type bar pivotally mounted on said shaft, a rockable member associated with leach bell crank, springs to said bell crank and said rockable member, holding means normally holding said bell crank and said rockable member inoperative in respect to the associated type bar against the pressure of said springs, means carried by said bell crank for aligning said type bar, means for gradually releasing said holding means, and means whereby said bell crank and said rockable member cooperate upon release of said holding means to align and apply pressure from said springs on said type bar. Y

7. Printing mechanism for a calculating machine comprising in combination settable type bars, a common transverse shaft, a bell crank to each type bar pivotally mounted on said shaft, a flexible lever associated with each bell crank pivotally mounted on said shaft, an operative connection between said lever and said bell crank, a lateral projection on one end of said lever adapted to ride in a guide slot in the associated type bar,` serrations on each of said type bars having a pitch corresponding to the spacing of the type on said bar, means on said bell crank for engaging said serrations on the associated type bar to align the same, a spring connected to the other end of said lever, a spring connected to the corresponding end of said bell crank, holding means normally holding said bell crank and said lever inoperative in respect to said type bar, against the pressure of said springs and means for gradj' ually releasing said holding means whereby said flexible lever causes said type bar to move towards and engage the aligning means on said bell crank, the type bar being moved to printing position subsequent to its alignment under the combined influence of the springs controlling both said flexible lever and said bell crank.

8. The combination with a settable type bar for a calculating machine of a bell crank, a flexible lever, an operative connection between said lever and said bell crank, serrations to said type bar having a pitch corresponding to the spacing of the type on said bar, a lateral projection on one end of said lever adaptedvto ride in a guide slot in said type bar, an aligning roller on the corresponding end of said bell crank adapted for engagement with said serrations, said bell crank and said lever being slotted for mounting on a common shaft whereby rocking of said bell crank and lever in one direction causes the type Cia aligning roller on the bell crank and subsequent to its alignment to move in the opposite direction.

9. The combination with printing mechanism as claimed in claim 1 of a no print device to each pressure device comprising a pivot, a stop member pivotally mounted on said pivot and adapted to normally engage under the associated type bar, a pawl pivotally mounted on said pivot, and having two arms, a lip on one arm of said pawl engaging over said stop member with a clearance between said stop member and saidlip and a tongue on the second arm of said pawl engaging said pressure device to prevent operation thereof in the normal position of the type bar, and a spring connected between the stop member and the first arm of said pawl whereby the tongue is released from said pressure device when the type bar is raised substantially as described.

10. Printing mechanism for a calculating machine comprising in combination settable type bars, a common transverse shaft, a bell crank to each type bar pivotally mounted on -said shaft, a first arm pivoted between its ends on said shaft adjacent each bell crank, a second arm pivoted on each bell crank, an articulated connection between each first and second arm, a lateral projection at the free end of said second arm adapted to ride in a guide slot in the associated type bar.

serrations on each of said type bars having a pitch corresponding to the spacing of the type onsaid bar, means at a free end of said bell crank for engaging said serrations in the associated type bar to align the same, a spring connected to the free end of said rst arm, a spring connected to the corresponding end of said bell crank, holding means normally holding said bell crank and said rst and second arms inoperative in respect to said type bar, against the pressure of said springs, and means for gradually releasing said holding means whereby said rst and second arms cause said type bar to move towards and engage the aligning means on said bell crank, the type bar being moved to printing position subsequent to its alignment under the combined iniiuence of said springs.

11. The combination with the printing mechanism according to claim 10 of a spring connected between the free ends of each bell crank and the associated second arm.

12. The combination with a settable type bar for a calculating machine, of a bell crank, a first arm, a second arm pivoted on said bell crank, an articulated connection between the rst and second arms, serrations on the type bar having a pitch corresponding to the spacing of the type on said bar, a lateral projection at the free end of the second arm adapted to ride in a guide slot in the type bar, an aligning means at the corresponding end of said bell crank adapted for engaging with the serrations, said bell crank and said rst arm being slotted for mounting on a commonshaft, whereby rocking of the bell crank and iirst arm in one direction causes the type bar initially to move towards and engage the aligning means on the bell crank and subsequent to its alignment to move in the opposite direction.

13. A no-print device for use with the mechanism according to claim l2, comprising a bar bored at one end for mounting on a pivot so that its free end can engage under the type bar to form a stop, a pawl in the form of a bell crank bored at its centre for mounting on the said pivot, a lip on one arm of the bell crank for engaging over the bar, a spring connected between the said arm and the free end of the bar, a tongue on the other arm of said bell crank for engaging a jaw on the bell crank associated with the type bar, and a lateral projection on the said other arm for engaging the corresponding arm of the next lower bell crank when mounted in the machine.

14. The combination with printing mechanism as claimed in claim 1 of a no print device to each pressure device comprising a pivot, a stop member pivotally mounted on said pivot and adapted normally to engage under the associated type bar, a pawl pivotally mounted on said pivot, and having two arms, the lip on one arm of said pawl engaging over said stop member with a clearance between said stop member and said lip, a tongue on the second arm of said pawl engaging said pressure device to prevent operation thereof in the normal position of the type bar, a spring connected between the stop member and the first arm of said pawl, whereby the tongue is released from said pressure device when the type bar is raised, a lateral projection on the second arm of each pawl adapted to engage the pawl associated with the next type bar of lower denomination, whereby when the pawl of Vhigher denomination is rocked the pawl of the lower denomination is also rocked, and spring controlled means for assisting rocking of the pawls.

WILLIAM BALL.

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