US2818800A

US2818800A - Wire printer

Info

Publication number: US2818800A
Application number: US400009A
Authority: US
Inventors: Robert J Orrange
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1953-12-23
Filing date: 1953-12-23
Publication date: 1958-01-07
Anticipated expiration: 1975-01-07
Also published as: DE961038C; GB767432A

Description

Jan. 7, 1958 R. J. ORRANGE'. 1 2,818,800

WIRE PRINTER s Sheets-Sh eet 1 Filed Dec; 25, 1953 FIG..1. 8 1

TF3 @I INVENTORQ ROBERT J. ORR/\NGE aw 42. WW

ATTORNEY 5 Sheets-Sheet 3 w #1 m P P w A? E w 4 7 m m m WW}! I A m W R. J. QRRANGE WIRE PRINTER Fi led Dec. 23, 1953 United Stats Patent WIRE PRINTER Robert J. Orrange, Vestal, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application December 23, 1953, Serial No.400,009 12'Claims. (01.101-93) This invention relates to wire printers andmore particularly to wire printers wherein selected ones of a plurality of print wires are displaced axially to undergo impact with recording material backed up by a platen.

Selective displacement of character forming wires has heretofore been accomplished with mechanisms such as that disclosed in U. S. Patent No. 2,524,127, issued to R.

B. Johnson on October 3, 1950. In such a mechanism a code plate mounted opposite the control ends of the print wires is first positioned in each of two'dimensions to dis- .pose a pattern of projections opposite the control ends of those wires whose print ends will form the component dots of a particular character. Thereafter the code plate is moved so that the projections strike the control end of the selected print wires to axially displace them against their bias to where the print ends of the wires undergo impact.

Such a plate must be formed of tough materials and, in addition, must be accurately fashioned. Obviously the construction of such plates is a relatively costly process.

Accordingly, it is an object of this invention to provide an inexpensive print wire selectingand operating mechanism. A more specific object is to provide a print wire selecting and operating mechanism which can be easily manufactured.

A further object of this invention is to provide such a ,print wire selecting and operating mechanism that is also accurate and reliable in operation.

Yet another object of the invention is to provide a print -wire selecting and operating mechanism which can be run at high speeds.

According to the invention, selected print wires are axially displaced to effect a printing by corresponding drive wires whose axial movement is controlled by perforated tapes located in the zone between the adjacent ends of the print and drive wires. The tapes, which are easy and inexpensive of construction and of comparatively light mass (now inertia), are so perforated that in their normal or home positions all of the drive wires may pass therethrough to engage the respective print wires. However, the tapes may be individually adjusted to other posi tions in which perforations are provided only for those drive wires whose corresponding print wires will effect a character pattern particular to the tape and its adjusted position. The drive wires are yieldably moved while piercing the zone occupied by the tapes so that those drive wires for which no perforations exist in the adjusted tape may be readily stopped. It can be seen that the number mined by the product of the number of tapes and the .positions to which eachtape may be adjusted from its home .position.

2,818,800 Patented Jan. 7, 1958 A'feature of this invention is that the drive wires are yieldably moved only while they are piercing the tape zone and that thereafter only those that completely pierce the tape zone are positively driven to insure that the selected print wires undergo impact. The driving element or bail, which is reciprocable through a fixed range, carries with it yieldable means which drivingly connect it with the respective drive .wires, and other means are provided which cooperate with-the'yieldable means to hold them against yielding in a portion of the range of the driving element which corresponds with the movement of the selected print wires. In one embodiment the driving element carries with it pivotally mounted pawls biased into sliding engagement with the respective drive wires which carry lugs disposed in the pawl paths. The bias of these pawls is such that the teeth thereon will not slide over the lugs while the respective drive wires are piercing the tape zone unless they strike a non-perforated portion of an adjusted tape; hence, the wires are yieldably driven while moving through the tape zone. After the end of a drive wire passes through the tape zone, an extension on the corresponding pawl will be confined by an associated protuberance on a lock bar, and the pawl will be held in positive driving engagement with the lug and thus with the drive wires.

The lock bar serves an additional functionnamely, that of providing a reset stop for those drive wires which had been disengaged from the bail, that is, stopped by the non-perforated portion of a tape. The tooth of a pawl when the drive wire is piercing the tape zone is located behind the lug thereon. If the drive wire is stopped by a tape, the tooth passes over the lug and hence is on the other side of the lug when the driving element restores. Under such a condition the pawl, through its driving engagement with lug on the wire, is effective to move the drive wire back. The pawl tooth gets behind the lug again through the action of the reset and lock bar which stops the drive wire in its normal position and forces the pawl tooth to move over the lug because of the continued movement of the driving element toward its normal position. The drive wires are slidably mounted at their rear ends on the bars to prevent lateral reflection thereof due to the unbalanced forces thereon arising from the use of only one pawl per drive wire.

The drive wires which are not stopped by a tape are restored with the bail and simultaneously therewith reach their home positions. Cooperating shoulders on drive wires and in the bail effect this restoration.

In a modification, two biased pawls are provided for each drive wire. Conveniently, these pawls consist of loop springs, the free ends of each being shaped so as to form teeth which are biased against the opposing surfaces .-of adjacent drive wires from intermediate points. Each drive wire is provided with two oppositely disposed lugs, and the flexible pawls are held in place by side platesfixed to the drive wires. Through the plates the pawls alsoact to hold the respective drive wires in place.

In a second modification, the two pawls per drive wire idea of the first modification is adapted to structures peculiar to the first discussed embodiment. The pawls for the opposing surfaces of the adjacent drive wires are juxtaposed on a shaft and are biased apart by an interconnecting spring. Of course, the lock bar is modified jto admit the second pawl for each drive wire.

7 Other objects of the invention willbe pointedout in the following description and claims and illustrated in the Fig. 1.

Fig. 3*is.an enlarged detailed view, partly'intsection, of a portion of the apparatus shown in Fig. l.

Fig. 4 is a view .showinga modified form of construction which may be employed in place of the mechanism shown in Fig.3. i

Fig. 5 is a view of a second modification which may be employed in place of the mechanism shown in Fig. 3.

Fig. 6 is a view'in perspective of a portion of the mechanism shown in Fig. 5. H i

Fig. 7 is a timing chart for :the invention.

Referring more particularly to the drawings, there is disclosed in Fig. 1 a base 10 rotatably supporting a platen 12 upon which arecord sheet 14 may be suitably mounted and advanced past a printing point generally indicated by the numeral 16. A print wire assembly, generally indicated by the numeral 18, is mounted opposite the platen, and a ribbon bearing transfer medium 20 is located between such assembly and the printing point on the record sheet. In the zone immediately behind the print wire assembly there are juxtaposed eight perforated tapes T1 through T8, each of which is individually adjustable. A tape selector mechanism, generally indicated by the numeral '22, is elfective to select the particular tape, and a tape positioning mechanism, generally indicated by the numeral 24, is actuated to adjust the selected tape to a desired position. Behind the tape zone is a reciprocable drive-wire assembly, generally indicated by the numeral 26, and behind that is a cooperating reset and lock bar 28.

In the print wire assembly 18, a plurality of print wires 30 are mounted in front of the ribbon 20 and the platen 12 in a tapered housing 32 generally rectangular in cross-section. The housing provides individual tubes or channels 34 (Fig. 3) for the respective wires to prevent lateral deflection thereof under the influence of endwise forces, and the ends of these channels or tubes are arranged in corresponding rectangular patterns on tions in which the print ends are out of control with the ribbon and the record sheet and do not interfere with the shifting thereof. In order to bias the wires, the housing is formed with two spaced plates 36 and 38 (Fig. 3) at its larger end. Aligned

apertures

40 and 42 are formed in these plates for the respective wires, and the wires project through the inner plate 38 and terminate in the outer plate 36. The tubes 34 terminate in the apertures 42 and are anchored to the inner plate 38. Between the two plates each wire is formed with a collar 43, and a compression spring 44 encompassing each wire reacts between such collar and the inner plate 38 to urge the print wires to their normal positions which are determined by the engagement of the collars 43 with the outer or rearward plate 36.

Each aperture 40 in the outer plate 36 is so formed However, on their outer or rearward side the print wires. Along the outer surface of the plate 36 the enlarged openings are flared so as to guide respective drive wires, after they pierce the tape zone, into engagement with the heads 48 of the corresponding print wires. It should be observed that the normal positions of heads 48 formed on the rear ends of the print wires are located a small distance forward of the outer surface of the plate 36 and hence also of the tape zone.

The drive-wire assembly 26 includes a reciprocable bail 50 in which drive wires 52 are mounted in aligned relationship with the control ends of the respective print wires. The bail is supported upon the base 10 by studs 51 extending through slots 53 formed in its opposite ends. Its normal position is such that the drive wires which project therefrom terminate just short of the tape zone. The bail is reciprocable from the normal position toward and away from the wire guide housing 18 and releasably moves the drive wires while they are piercing the tape zone; thereafter it positively moves those which pass therethrough so as to impress a firm printing stroke upon the selected print wires.

Movement of the bail is effected by a pair of single lobed cams 54 operating against rollers 55 carried by the bail. The bail is caused to follow the contours of the cams by tension springs 56 anchored at their for ward ends to studs 58 fixed to the bail 50 and at their rearward ends to studs 60 fixed to the lock bar 28. The cams rotate together and so that the high points thereof engage the bail rollers at the same time to move the bail toward the print wire guide housing 18. When the cam high points recede, the bail is restored to its normal position under the action of the springs.

The drive wires 52 are slidably carried by the bail 50. They are caused to move with the bail toward the print wires through cooperating lug and pawl arrangements. A generally triangular shaped lug 62 is formed on a rearwardly projecting portion of each drive wire and is ad'aptedto be engaged by the complementarily shaped tooth 64 formed on a corresponding pawl 66 (see Fig. 3). p

The pawls 66 are. pivotally mounted on rods 68 carried by the bail between the different rows of drive wires. Springs'70 coacting between the respective pawls a and the bail bias the pawls into engagement with the respective drive wires.

The. normal position of the bail is such that thepawl teeth engage the respective drive wires between the lugs 62 formed thereon and the rear ends thereof. It can be seen that, with sufficient bias and the appropriate design of the complementary surfaces on the lugs and pawl teeth, the drive wires may be made to move with the bail toward the print wire assembly 18. By the same token it may also be observed that, should any of the drive wires be stopped as by engagement with an unperforated portion of a tape, the associated pawls would pivot so that the teeth slide over the lugs on the corresponding drive wires, thus permitting the pawls to continue movement with the bail without thereafter exerting any significant driving force upon the drive wires.

As pointed out earlier, the drive wires are yieldably moved while piercing the tape zone, and that thereafter they are positively moved to insure displacement of the selected print wires 30. The positive moving of the drive wires which pierce the tape zone is effected through the reset and lock bar 28. This bar, which is suitably fixed to the base 10, is formed with a hole 72 at the rear end of each drive Wire so as to receive both the drive wire and the tooth portion of the associated pawl. The bar 28 is so located and the hole is of such depth that reciprocation of the pawls due to reciprocation of the bail takes place in these holes. The interior ends of the holes are of such 7 size so as to permit the pawls to pivot and ride over the lugs ontheassociated drive wires.

This permitswyieldable moving of the drive wires while the same are piercing the tape zone. Hence, if a drive wirei iststopped by bail movement continues.

i1 tion that is rectangular in cross-section. -tion is rectangularto keep the wires from rotating-and I =t-husin'sur'es that the lugs 62 will remain aligned with -the re'spe'ctivepawls 66. A shoulder 78 exists on each ike non-perforated portion of a tape, its drive will be i 'is maintained between the bail and the selected-drive wires. tension 74 on each pawl which engages a protuberance This is accomplished through an inclined ex- 76 formed by the reduced size of each hole entrance to prevent the tooth from riding over the associated lug. T he extension 74 and the protuberance 76 are so formed and located that the pawl 66 is held against pivotal movement while the drive wires are displacing the print wires. On the other hand, the extensions 74 and the pro- .tuberances 76 are also so formed and located as to admitv "of some bail movement between the point where the 1 drive wires completely pierce the tape zone and the point where the pawls become held against'pivotal movement.

This is necessary to permit the pawls to ride over the lugs inthose cases where the drive wires are stopped by the last tapes, such as T7 and T 8.

I It should be observed that when a drive wire is stopped, for example by tape T8, it is still necessary that the pawl be able to ride over the lug before the forward drive relationship therebetween is discontinued. Thus, there must be sufiicient clearance in the corresponding hole 72 to permit this pivotal movement of the pawl to take place. The extra distance that is needed is only that which permits the pawl tooth to ride over the crest of the lug. For thereafter the pawl tooth may act on the forward inclined slope of the lug to force the drive wire backward to where the lug is no longer beneath the pawl tooth. This action is made positive by the engagement of the inclined extension with the cam surface 77 on the protuberance 76, which engagement forces the pawl downward as the The point of bail movement is so reached where extensions for all of the pawls are beneath the protuberances 76, and positive driving 'Of add the selected drive wires will be effected. The distance that thebail moves after the drive wires pierce the tape zone and before the pawls are locked against pivotal movement is less than that between the last tape and the heads 48 formed on the rearward ends of the 'priritwiresSll, so that when the drive wires engage the print wires, they are being positively driven and cannot be stopped by the added'load of the print wires.

The drive wires are restored with the restoration of the bail to its normal position. In the case of those drive wir'es which were moved all the way by the bail, itcan be seen that the pawl tooth 64 remains behind the lug and; thus, is of'no avail so far as restoration of the respective 'dr'ivewire is concerned. The restoration of such drive Wire's-is accomplished-by providing cooperating shoulders on the driv'e wire and the bail. Asshown in Fig. 3, the drive iwires are formedof two distinct portions -a front portion'that-is circular incross-section and a rear por- The rear porwire at the junction of the front portion with 'the' rear jporti'on. ';The bail holes are formed of complementary shapes and have shoulders 80 formed at-the junctions'of the difiere'ntly shaped portions. When the bail recedes, the shoulders 8d of the bail holes engage the shoulders 78 of-th'eselected drivewires to restore them with the bail'to 'their n ormal positions.

-:The drivewires which were stopped by anon-perforat- ."ed portion'of a selected tape have their lugs 62 disposed .;behind the teeth 64 of the associated pawlswhe'n the :bail begins to restore. Thus, these drive wires are restored by the action of the pawls instead of by the cooperating

shoulders

78 and 80 which are separated at this time. Their rearward movement is terminated when they have arrived in their home positions by the engagement of their rear ends with the rear end of reset bar openings 82 in which they are slidably disposed. After the drive wires arrive in their home positions, the respective pawl teeth ride over the lugs thereon. When the bail comes to rest in its normal position, the pawls will have been reset in proper driving relationship to the drive wires.

It :may be observed that the side ofv the drive wires vopposite that on which the lugs are formed rest uponthe reset bar material surrounding the, holes 72. This 'is to length (Figs. land 2). the tapesare juxtaposed 'frontwise to form a tape zone, .andthey are held against the backside of the rear plate minimize the deflection of the drive Wire by the biased pawls.

' Returning to the tapes T1 throughTS, each is formed as a thin steel band of some width and considerable The intermediate portions of I .36 of the print -wire guide housing 32 by upper and lower setsof .guides83a and 83b, respectively, which also slidv ably receive thetforward end of the bail'50. The interfitern because all, of =the ,perforations for one print wire mediate portions areperforated in a nondescript pet appear in a column before those for the next and be- ;cause the positions to which tapes are adjusted are those which present successive rows of perforations to the rows of iprint wires.

The tapes are supported at their 'upper endsby individual tension springs 84 anchored at their upper ends to a member'86 tfixed to the baselll. To facilitate the attachment of the tension springs tothe respective tapes,

the upperendsofjthe tapes are offset from their intermediate portions as may be best seen in Fig. 1. It may be noted that the-springs bias each of the tapes upwardly from their normal or=home positions.

--The tapes are usually held in their normal positionsby =a. M11388 of the tape positioning mechanism 24. The ,lower end-of'each tape is formed withan elongated opening; .(Fig. 2),-,and a transverseportion 88a ofaloop formed on the upper end of the bar is seatedin these openings. A tension spring 92, heavy-enough to,=overcome the combined bias of the tension springsj84 at the upperend -'of.the tapes, is connected between the lower 7 end 'of the tapepositioner bar 88 and afixedstud 94 'fixed to"the base 10. 'Spring .92 acts to urge the'tape positioner bar together with thetapes to their normal positions.

=These normal positions of the ,tapevare determined by a bar 96 of the tape selector mechanism 22. The bar is slidably supported at 'its right hand end .(Fig.-,1) by a setof vertically spaced guides =98, and at its left hand end -it is :heldagainst vertical displacement by the restof the selector mechanism'22. It extends through a second set of, openings 98 formed in the respective tapes above the openings 90. The openings are of such size that the bar is snugly yet slidably-received therein. .Thus, the

=tape selector barzwill h-old-thetapes in their normal position-even .when the -.tape' .positioner bar-is moved upward by the tapepos itioner-mechanism. This is itrue for-all except-the.tapedisposed intline witha slot 100 formed in the bottom side of the tape selector bar. The selected or aligned tape moveslupwardly in theslot to aposition which is determined by how, far the tapepositioner bar .88 is moved upwardly againstthe 'bias of the heavy spring "92. 'Thus it 'can beseen that, by suitable control .Q tape d b -QQand bfthe tape positioner bar 88, any one of they tapes may be moved to any of a number of difierent' positions. Magnet actuated adding linkages in 'thetape selector'mechanism 22 andirf'the tape positioner mechanism 24 provide this control.

The adding linkage for the tape selector mechanism fixes the home position to which-the tape selector bar "96 the right the thickness of four tapes.

f' is aligned with the first or left hand tape T1" (Fig. 1).

. The adding linkage consists of three bell cranks 104,106,.

and 108 which are respectively controlled by t'apes'elector magnets T51, TS2, and T53. Bell crank 104 is pivoted upon the upper end of the upstanding arm 106a of bell crank 106. The energization of magnet TS1- attracts the horizontal arm 104b from its stop 110 to swing it clockwise an amount which will move the tape selector bar the width of one tape to the right. Thus, if magnet T31 is the only tape selector magnet energized, the slot 100 will be in line with the second tape T2. It may be observed that stop 110 determines the position to which the bell crank 104 may be rotated upon the bell crank 106 by the spring 102 and, thus, partially determines the home position to the tape selector bar.

Bell crank 106 is pivotally mounted on the free end of the upstanding arm 108a of hell crank 108. Energization of magnet TS2 attracts the horizontally extending arm 106b of hell crank 106 from its stop 112 to swing the bell crank clockwise. The upstanding arm 106a of bell crank 106 is of substantially the same length as'the upstanding arm 104a of bell crank 104, and it may be observed that since the former carries the latter with it, its effective moment arm is twice that of hell crank 104. Thus, energization of magnet TS2 will efiect a movement of the tape selective bar which is equal to the thicknesses of two tapes. When energized by itse1f,-slot 100 will be aligned with tape T3.

Bell crank 108 is pivotally mounted at its bend at a fixed support bracket 114. Its upstanding arm 108a is equal in length to the combined lengths of the

upstanding arms

104a and 106a of hell cranks 104 and 106 and carries with it these bell cranks. Hence, its eifective moment arm is four times that of hell crank 104 and twice that of bell crank 106. When magnet TS3 is energized, the horizontal arm of bell crank 108 is swung from its stop 116, and the tape selector bar is moved to Thus, if magnet TS3 alone is energized, the slot will be disposed in align- 'ment with tape T5.

--It will be appreciated that the tape selector magnets TS1, TS2, and TS3 maybe energized singly or in com- *bination to shift the bar 96 against the action of spring 106 the thickness of from one to seven tapes. A shift equal to three thicknesses will be accomplished by an energization-of magnetsTSl-and TS2, one equal to five thicknesses by an energization of magnets T81 and T53, and one equal to six or seventhicknesses by an energization of magnets T52 and TS3 or all of them.

-.The tape positioner-mechanism adding linkage is like that for the tape selector mechanism save that it is disposed horizontallybecause the tape-positioner bar 88 is home positions.

bar 96 and caused to .follow the bar 88 by its spring 84 is disposed in the first, second, or fourth remote from The third, fifth, sixth, and seventh positions of a tape are respectively obtained by a combinational energization of the magnets TP1 and TP2, TP1

and TP3, TP2 and TF3, and all of them.

From the foregoing it will be evident that, by a suit "able energization of the tape selector and the tape posi- H tioner magnets, any one of eighttapes may be selected I 'andfmov'ed from its home position to any of seven other .positions. Thus, any one of fifty-six characters may -Qre a dily be selected"for-printing; In the following table are llisted separately, for each character that may be printed, ,the tape; and; the a combination of tape: selector magnets energiz ed togetherwith the position -to which the selected tape is moved and thecombination of tape position magnets energized.

Selected Tapes Position Character:

WNMWNWWOJWNWWWWWWWWWW MWCAJMWWNMNIONMNNNMMMNNNNHHHHHHH been arbitrarily chosen in the absence of embodiment in a specific machine as the time at whichone or more of'the tape selector magnets TS1, TSZ, and T53 are pulsed if the character to be printed is on a tape other than the first tape T1. Their energization results in a shift of the tape selector bar96which may be completed by 62.5 degrees of cycle time. With the slot 100 aligned with the tape bearing the desired character, the tape positioner bar may be positioned. Thus, one or more of the tape positioner magnets TP1, TF2, and TP3 are, energized at 62.5 degrees of cycle time, and theselected tape will be adjusted to the character determining position under the influence of its spring 84 by degrees of cycle time. At this point the lobes of the cams 54 advance upon the bail 50 and'move it so that thedrive wires 52 attempt to pierce the tape zone and strikethe respective print wires 30. Certain of the drivelwires will be stopped by unperforated portions in the displaced tape, and will remain in these stopped positionsasIthe bail restores. At 180 of cycle time the selected print wires will have been displaced to where impact'occurred with the recording material backed up by the platen 12, and the bail will begin a restoration under the influence of springs 56 as the lobes of the cams 54 recede. This restoration is completed at 225 of cycle time. Thereafter the tape positioner magnets are deenergized, and the spring 92 lowers the tape positioner bar 88 to withdraw the adjusted tape from the slot 100 in the tape selector bar 96. When the selected tape has been fully restored to its normal position, for example,'at 287.5" of cycle time, those tape selector magnets which were energized, if any, are dropped. Thus the tape selector bar may be fully restored to its normal position by the end of the cycle, and the above described cycle of operation may be repeated in the next cycle.

In Fig. 4 there is shown a modification of the drive wire bail assembly 26 and reset and lock bar 28 shown in Fig. 3. In this modification two pawls 120 are provided for each drive wire 122. Conveniently, the pawls are formed of loop spring material in which the loop 129 is mounted on the rods 68 between adjacent rows of drive wires, and the free ends of the springs are angularly shaped to form teeth 126 which bear against lugs 128 formed at opposite sides of the drive wires. Integral extensions 130 formed on the pawls 120 engage projections 132 formed on the reset and lock bar at the entrance to the holes 72 which have been enlarged to accommodate the two pawls for the respective drive wires. Plates 134 are aflixed to opposite sides of the drive wires to hold the flexible spring pawls 120 in engagement with the drive wires. It may be observed that the plates slidably abut the projections 132 of the reset bar to guide the rear ends of the drive wires. The op eration of the drive wires by bail 50 and the reset bar 28 is the same as in the earlier modification save that those drive wires which were stopped by a tape are restored by the engagement of the bail 50 with the plates 134 rather than by cooperating shoulders on the wires and in the bail holes.

Still another modification of the drive Wire bail assembly 26 and the reset and lock bar 28 is shown in Figs. and 6. Therein two pawls 136 for each spring, instead of being formed of flexible spring material as shown in Fig. 4, are formed of rigid material as were the pawls of Fig. 3. The vertically aligned pawls for opposing sides of adjacent drive wires 138 are juxtaposed on the rods 68 between the rows of drive wires and biased apart by a piece of spring material 140. Thus, no side plates are required in this modification, and, therefore, the unset drive wires are again restored through

coopcrating shoulders

142 and 144 formed on the drive wires and the bail. At their rear ends the drive wires are guided in reduced openings 146 in the holes 72 of the reset and lock bar 28.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In a wire printer, a plurality of print wires movable axially to undergo printing impact, a corresponding number of axially movable drive wires respectively aligned with said print wires, a number of perforated elements each having a normal position in which perforations are aligned with all of the drive wires and adjustable to positions in which perforations are only aligned with different ones of said drive wires, and means for moving 10 each of the perforated elements to its different positions for individual'character selection.

2. In a wire printer, aplurality' of print wires movable axially to undergo printing-impact, a corresponding'number of axially and yieldably movable drive wires respectively aligned with said print wires, a plurality of perforated tapes disposed between the adjacent ends of the drive wires and the print wires and each having a normal position in'which perforationsare aligned with all of the drive wires and other positions in which perforations are only aligned with different ones of said drive wires and the movements of other of said wires will be arrested by the non-perforated positions thereof, and means for moving any of said tapes to any of its other :positions for individual character selection.

3. In a wire printer, a plurality of print wires movable axially to undergo printing impact, a corresponding number of axially movable drive wires respectively aligned with said print wires, a plurality of perforated tapes disposed between the opposing ends of the drive wires and the print wires and having normal positions in which perforations are aligned with all drive wires and other positions corresponding to different characters and in which perforations are-only aligned with those drive wires which move print wires forming'component-dots of the character pattern, means for selecting the tape bearing the perforations of the desired character, and means for moving the selected tape to character determining position.

4. In a wire printer, a plurality of print wires movable axially to undergo printing impact, a corresponding number of axially movable-drive wires respectively aligned with the said print wires, a plurality'of perforated and upwardly biased tapes disposed between the opposing ends pose a. notch in alignment with the different ones of said tapes, said notch permitting upward movement of the aligned tape, a solenoid controlled linkage for moving the selector bar, a positioner bar biased to hold the tapes in their one positions and movable so as to permit the aligned tape to move upwardly in the notch, and a solenoid cont-rolled linkage for moving the positioner bar upwardly.

5. In a wire printer, a plurality of print Wires movable axially to undergo printing impact, a corresponding number of axially movable drivewires aligned with said print wires, perforatedmeans disposed in the zone between the drive wires and the print wires and adjustable to various positions in which perforations are aligned with different ones of said drive wires, means for yieldably moving said drive wires while piercing the perforated means zone, and means for thereafter positively moving those drive wires which pierced the perforated means zone until the respective print wires undergo printing impact.

6. In a wire printer, a plurality of print wires movable axially to undergo printing impact, an element movable towards and away from said print wires in the axial direction thereof, drive wires slidably carried by the movable element and aligned with respective ones of said print wires, perforated means disposed in a zone between the print wires and the drive wires and adjustable to various positions in which perforations are aligned with different ones of said drive wires to permit their engagement with aligned print wires, cooperating means on said drive wires and the movable element for yieldably connecting said drive wires with said movable element, and means for preventing yielding of the connections between said drive wires and said movable element after the movable element has carried those drive wires aligned with perforations through the perforations.

7. In a wire printer, a plurality of print wires movable axially to undergo printing impact, a corresponding numher of drive wires aligned with said print wires, perforated means disposed in azone between the print wires and the drive wires and adjustable to various positions in which perforations are aligned with different ones of said drive wires to permit their engagement with respective onesof said print wires, a receiprocable member in which the drive wires are slidably mounted, lugs formed on the respective drive wires, pawls carried by the reciprocable member and biased into engagement with the respective drive wires, said pawls each having a tooth adapted to engage the lug on the corresponding drive wire, an ex tension formed on each pawl, and a fixed part overlying a part of the path of each pawl extension so as to prevent movement of the associated pawl tooth over the lug on the corresponding wire after the drive wire has passed through an aligned perforation.

8. In a wire printer, a plurality of print Wires movable axially to undergo printing impact, a corresponding number of drive wires aligned with said print wires, perforated means disposed in a zone between the drive wires and the print wires and adjustable to various positions in which perforations are aligned with different ones of said drive wires to permit their engagement with respective ones of said print wires, a reciprocable member in which the drive wires are slidably carried, lugs formed on opposite sides of each drive wire, springs formed with tooth shaped angular portions carried by said reciprocable member and biased so as to engage respectively opposite sides of the different drive wires, plates mounted on opposite sides of each drive wire to hold the springs onto the drive wire, extensions formed on the toothed portions of said springs, and parts overlying the paths of the spring extensions so as to prevent movement of the associated teeth over the lugs on the respective drive wires after the drive wires have passed through aligned perforations.

9. In a wire printer, a plurality of print wires movable axially to undergo printing impact, a corresponding number of drive wires aligned with said print wires, perforated means disposed in a zone between the drive wires and the print wires and adjustable to various positions in which perforations are aligned with different ones of said drive wires to permit their engagement with respective ones of said print wires, a reciprocable member in which the drive wires are slidably carried, lugs formed on opposite sides of each drive wire, pawls for the respective lug-s pivotally mounted on said reciprocable member and engaging the opposite sides of the drive wires, the pawls for the opposed surfaces of adjacent drive wires being pivotally and juxtaposedly mounted on common elements and biased apart by an interconnecting spring, extensions formed on the respective pawls, and parts overlying the paths of the extensions so as to prevent movement of the pawl teeth over the lugs on the respective drive wires after the drive wires have passed through aligned perforations.

10. Ina drive mechanism, a driving element reciprocablethrough a fixed range, a driven element, a toothed pawl pivotally carried by said driving element, a lug formed on the driven element, a spring biasing the toothed pawl into engagement with the driven element with such force that upon engagement with the lug thereon it will ..move the driven element, an extension formed on the pawl, and a fixed part overlying the path of the extension during a portion of the range of movement of the driving element to prevent yielding of the pawl.

11. In a drive mechanism, a driving element reciprocable through a fixed range, a driven element, lugs formed on opposite sides of the driven element, springs formed with tooth-shaped angular portions and carried by said driving element and biased so as to rest in engagement with the respective sides of the driven element, plates mounted on opposite sides of the driven element to hold the tooth-shaped portion of the springs in engagement with the driven element, extensions formed on the respective springs, and fixed parts overlying paths of movement of the extensions to prevent yielding of the springs during a portion of the range of movement of the driven element.

12. In a drive mechanism, a driving element reciprocable through a fixed range, a plurality of driven elements, lugs formed on opposite sides of each driven element, pawls carried by the driving element and respectively engaging the sides of the driven elements bearing the lugs, the pawls for the lugs on opposing surfaces of adjacent driven elements being juxtaposed on the same rod and biased by interacting springs, extensions formed on each pawl, and fixed parts overlying the path of movement of said extensions during a portion of the range of movement of the driving element so as to prevent yielding movement of the associated pawls.

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