IBM Selectric I/O Manual Of Instruction Download

Page: 1 / 102

Summary of Contents for Selectric I/O

Page 1: ...ter Customer Engineering Manual of Instruction Issued to ___________________ Branch Office _________________ Department _________________ Address ___________________ If this manual is mislaid please return it to the above address ...

Page 2: ...er 1964 The particular model you are concerned with may not use all of the mechanisms de scribed This manual covers models 731 735 765 775 1415 1014 Sabre Stretch 7040 44 1620 Mod I All rights to reproduce this material are reserved by IBM Address comments regarding the comments of this publi cation to IBM Office Products Divi sion Lexington Kentucky 40507 ...

Page 3: ...hanism Late Style 41 Print Escapement 41 5 Mainspring 44 Operational Cams and Control Mechanism 45 Operational Selection Unit 49 Operational Contact Assembly Late Style 50 1 Spacebar 51 Spacebar Mechanism Print Escapement 54 Backspace 54 1 Carrier Return Early Style 55 Carrier Return Late Style 58 1 Indexing 59 Platen Variabl e 62 Tabulator 63 Margin Control 69 Paper Feed and Release ME tchanism 7...

Page 4: ... 2 INDEX SELECTION LEVER I COpy CONTROL LEVER 3 PAPER RELEASE LEVER 4 PAPER BAIL LEVER 8 7 ON OFF SWITCH TAB SET CLEAR SELECTRIC 1 0 KEYBOARD PRINTER ...

Page 5: ...Re lease Lever Move the paper release lever forward to position or re move paper 4 Paper Bai I Lever Holds the paper against the platen to prevent buckl ing Should be moved forward when inserting paper 5 Margin Set Leve Provides the operator with a means of changing the margin settings 6 Index Key Provides vertical indexing of the paper without changing the posi tion of the carrier assembly 7 On O...

Page 6: ......

Page 7: ...led for a period of time therefore there is no dangerof an open circuit during normal operation The motor will stall only in rare cases where a maladjustment or parts breakage causes the machine to lock After the motor has re gained normal temperature the circuit breaker wi II again close the circuit The circuit breaker will continue to open and close as long as the motor is stalled and the switch...

Page 8: ...ver shows just above the case This calls attention to the fact that the machine is ON to minimize chances of the machine being left running when not in use In addition to operating the typewriter switch the switch lever also controls the keyboard lockout mechanism This mechanism is discussed in the keyboard section Motor Contactor 835 Printer Mounted underneath the printer near the shift feedback ...

Page 9: ...hen the motor is OFF the pawls are spring loaded against stop lugs on the clutch plate When the motor is turned ON the clutch plate turns with the rotor Centrifugal force causes the clutch pawls tC pivot on the studs of the cI utch plate so that the ti p of one of the pawls engages a tooth of the motor pulley Fig 5 The pulley is then caused to rotate and drive the machine by means of the cycle clu...

Page 10: ...d in position at the extreme left end of the shaft by two set screws Two nylon inserts fit into the cut outs of the torque limiter hub around the extensions of the cycle clutch pulley hub The inserts provide a noiseless driving connection be tween the two hubs Just to the right of the torque limiter hub are three spring clutches and two small pinion gears These components are part of the carrier r...

Page 11: ...form located within the rear por tion of the carrier Fig 11 Its purpose is to carry the type head to and from the platen for the print operation Compon ents involved in the typehead positioning and aligning opera tions are also contained within the rocker The rocker pivots on the rocker shaft at the rear of the carrier Two bushings pressed into the rocker pivot on the shaft and act as the bearing ...

Page 12: ...d in one position only Fig 14 The head must be rotated as it is insta lied unti I it drops into position on the pin The spring c lip is then released to lock the head in place When the mechanism is at rest the typehead is always in the home position When the shift mechanism is in the low er case position the ears of the head clip are toward the front of the machine TILT MECHANISM Tilt Operation Th...

Page 13: ... a pivoting arm ca lied the ti It arm Movem ent of the arm to the left ex erts a pu II on the ti It tape to cause a rotation of the ti It tube and a ti It to the typehead left Hand Tilt Pulley Tilt 2 latch Tilt 1 latch late Style Gearless Ti It The gearless tilt m chanism operates basically the same as the previous mechanism Movement of the ti It ring is ac complished by the operation of the ti It...

Page 14: ...ht deal with rotating the head The second latch from the left is referred to later If the latches remain to the rear under the plate they wi II be pulled down when the bail is operated If any latch is held forward it is not hooked under the bai I plate and wi II not be pulled down during an operation of the latch bail The meth od of operating the various latches forward is discussed in later secti...

Page 15: ...rinting position FIGURE 22 Ti It 2 Operation When both latches remain to the rear under the latch bail both are operated The lever moves straight down and neither end acts as a pivot point Fig 23 This causes the double vertical link to receive the same motion as the latches resulting in three character bands of ti It The fourth band is then in the printing position 8 FIGURE 23 Tilt 3 Operation Whe...

Page 16: ... typehead is rotated counterc lockwise by the pu II of the tape When either side pulley moves toward the other the typehead is rotated clockwise by the tension of the rotate pulley spring Fig 25 The rotate spring is of the mainspring type enclosed in a sta ti onary cage with the outer end of the spri ng attached to the cage The inner end of the spring is connected to a hub on the rotate pulley A s...

Page 17: ...ai I operates Fig 27 As the middle latch is pulled down its attached lever moves down 10 at the left and pivots at the right on a stop lug formed out from the differential bracket The vertical link is attached to the lever one thi rd of the distance from the pivot point to the latch This causes the link to be moved down one third as much as the latch This Point Stationary On All Positive Selection...

Page 18: ...right end of the lever must be raised The right end of the balance lever has a flat link connection to the five unit bai I assembly Fig 30 The bai I is a single arm located under the cycle shaft and pivoted in front on the bail shaft When the five unit bail is allowed to rise the right end of the balance lever rises to allow clockwise operation of the rotate bellcrank 5 Unit Drive Link characters ...

Page 19: ...ell crank Operating one or more positive rotate latches down in con junc tion with allowing the five unit bail to rise allows different amounts of negative rotation The positive rotate one and negative five combine to allow a negative four rotation A positive two and negative five combination gives a negative three rotation Fig 34 A positive three and a negative five operation permits a negntive t...

Page 20: ...ug on the bottom is common to all interposers It is a wide lug located at the middle of the interposers Its purpose is to release the cycle clutch for a cycle operation whenever a keylever is depressed Directly below the lug is the cycle bail that pivots up and down Fig 35 Downward movement of any character interposer forces down on the cycle bail to release the cycle clutch latch and allow a cycl...

Page 21: ...y would partially block the depression of an interposer and the keyboard touch would suffer The stops are removable so that the steel balls may be removed and cleaned if necessary Selector Bails and Links Seven se lector bai Is are mounted between the si de frames so they can operate forward and back Fig 35 Each bai I is in front of a selector lug position on the interposers When an interposer con...

Page 22: ...Early Style Restoring Mechanism For a cycle operation the cycle shaft must be limited to 180 0 rotation This means that the cycle clutch latch must be re stored and held to the rear into the path of the second step on the cycle clutch sleeve A two piece adjustable restoring de vice pivots on the cycle clutch latch bracket As the filter shaft rotates during a cycle operation a blade ofthe filter sh...

Page 23: ...appl ies to the negative 5 latch except that its bail is allowed to rise in the operated position The negative 5 latch resets above its bai I when the bai I has been driven down to its rest position If the keylever has been held down throughout the operation the rear edge of the interposer lug strikes the keylever pawl as the interposer restores to the rear The keylever pawl is then deflected to t...

Page 24: ...aft assembly They are located between the positive cams on the cycle shaft They are called latch pusher corns The purpose of the corns is tooperote the selector latch pusher bail As the cycle shoft begins to turn the cam follower arms raise the latch pusher bail Fig 45 Further rotation of the cycle shaft causes the pusher bail to lower Fig 46 When the cycle clutch latches the bail is restored to i...

Page 25: ... as the bai I moves down Restoring the Selector Latch Pushers The selector latch pushers are restored by the selector latch pusher bail The bail forces the tails of the pushers down causing the pushers to pivot on a shaft The top of the pusher moves to the rear allowing the selector latches to return under the selector latch bai I The pusher bail must restore the pushers far enough to allow the ar...

Page 26: ...ows the five unit bai I to rise The contact actuator rises under the tension of the contacts Fig 52 Code Check Parity Check The purpose of code check is to determine if the correct num ber of selector latches are active during a print selection cycle Code checking requires the addition of another selector bail selector latch latch pusher and magnet Fig 53 The selec tor latch has no mechanical func...

Page 27: ...ased As additional insurance against an interposer being latched down a special bellcrank at the left side of the keyboard is rotated into the selector compensator by a Iink from the lock out bail This forces the steel balls to shift in the tube and block the downward movement of all interposers When the switch is ON the keyboard lock bellcrank is spring loaded out of the selector compensator A li...

Page 28: ...ch pawl is locked Functi ona I Keylevers The functional keylevers are locked by the link on the right end of the bai I The link is fastened to the bai I by an adjust able clamp The end of the link that extends to the front fastens to a be Ilcrank The be Ilcrank pivots around the screw that mounts it to the keylever support As the link moves to ward the front the be IIcrank is rotated in a counterc...

Page 29: ...eyboard side frame The magnet armature extends upward and contacts a lug on the shift lock interposer Fig 59 1 When the mag net is energized the armature moves forward pulling the shift lock interposer forward releasing the shift lock latch 22 Shift Lock Sh ift Lock Magnet FIGURE 59 1 Shift Lock Release 835 Printer Cyc Ie Clutch Paw I Stop Mounted on the lock bai I and spring loaded to operate wit...

Page 30: ...e shift lock is attached to the left keylever and may be locked by depressing the shift lock keybutton The shift lock may be released by depressing and releasing either shift keybutton The right hand rotate pulley is fastened to thE top of the shift arm The arm pivots to right on a pin at the bottom A strap from the shi ft arm to the pivot pin acts to stabi Ii ze the shift arm to minimize front to...

Page 31: ...ring a shift operation and re ceives its motion from the operational shaft Since the op erational shaft turns continuously when the motor is running a clutch mechanism is required to engage and disengage the shift cam from the operational shaft when a shift operation is desired A spring clutch makes and breaks the driving connection between the operational shaft and the shift cam The shift cam mou...

Page 32: ...the shift release arm is controlled by a link from the arm to a lever attached to the end of the shift bai I Fig 61 When a shift keylever is depressed the bail rotates to force the link to the rear and operate the shift release arm When the key levers are at rest the release arm is in position to stop the inner lug of the shift clutch ratchet Fig 64 Depression of a keylever causes the release arm ...

Page 33: ...des a raised surface on the circumference of the cam Fig 66 The friction applied by the brake prevents acceleration of the cam and causes the shift action to be the same for both upper and lower case Character Interrupter If the shift is already in process when a letter key is de pressed the character must be delayed until the shift is com pleted Otherwise the shift wou Id be interrupted in rnid C...

Page 34: ...erate the shift immediate Iy after striking a character the shift cam could begin to rotate be fore the filter shaft had sufficient time to actuate the shift interlock This could cause an erroneous character to print because the shift arm had already begun to move This is known as beating the shift This condition occurs mostly in shifting from upper to lower case Shifting from lower to upper case ...

Page 35: ...rmed end that extends to the rear and serves as a latching surface Fig 70 The lower case magnet armature is spring loaded to the front against the formed end of the upper case armature Fig 71 Pivot Plate FIGURE 70 Upper Case Magnet Armature Coil Stop Plate FIGURE 71 Lower Case Magnet 26 1 ...

Page 36: ...tact Assembly 27 Contact Cam Follower Actuating Arm The cam follower arm ri des the peri phery of the shift cam It is spring loaded toward and follows the contour of the cam The contact cam follower arm is positioned on the cam to lead the shift arm by 90 0 In upper case the shift cam is detented so the shift arm rests on the high point of the shift cam Fig 74 In lower case the cam is detented so ...

Page 37: ...cter prints Everything concerned with printing a character on the paper is powered by the cycle shaft either directly or indirectly The cycle shaft extends from the center of the machine out through the left side frame The left end of the shaft is sup ported by a self aligning bearing The right end fits into the cycle clutch pulley hub in the center of the machine A sleeve inside the hub acts as a...

Page 38: ...ft wi II return exactly to its rest position at the com pletion of each cycle operation The cycle shaft is in its rest position when the positive selector cams are on their low dwells and the working face of a notch on the check ratchet is against the working face of the check pawl The shock of stopping the overthrow of the cycle shaft fi Iter shaft and print shaft is transmitted from the cycle sh...

Page 39: ...positions A small arm called the ti It detent mounts in a slot on the left si de of the yoke and oper ates in the notches on the ti It ring When the ti It ring is operated to approximately the correct tilt position the tilt detent is allowed to enter one of the notches in the ti It ring Fig 81 A heavy extension spring causes the detent to seat in the V shaped notch thus camming the tilt ring into ...

Page 40: ...t position provides a method of visually measuring how much coarse alignment variation there is in the system and also which adjustment or adjust ments is causing the variation Each adjustment in the sys tem affects coarse alignment in a different manner and shows up in a definite pattern By observing the pattern a mal adjustment in system can easi Iy be diagnosed Example Figure 85 illustrates a c...

Page 41: ... the left the ti It de tent moves down pushing the rotate detent down with it When the actuating lever moves to the right both detents are a IIowed to rise Movement of the detent actuating lever is controlled by the detent cam through the detent cam follower Fig 87 The cam follower i pivoted on a bracket below and to the rear of the print sleeve and extends up alongside the detent cam in position ...

Page 42: ...nt that are indirectly involved in the wear compensator action At this time consider only the three parts mentioned The rotate arm Fig 90 pivots on a large pivot pin in a bracket mounted to the left side of the power frame The left hand rotate pulley operates at the top of the rotate arm The compensating arm pivots at the same point as the rotate arm and extends in two directi ons from the pivot T...

Page 43: ... supply five units of motion to the compensating arm when a negative 5 character is selected The rotate arm cannot travel a full five units because this wou Id carry it be yond the sideframe The sideframe limits the motion of the rotate arm at exactly the rotate negative five position Since there is nothing to stop the motion of the compensating arm it continues to travel the full five units of mo...

Page 44: ... up as play The compensating arm spring would pull the top of the compensating arm in a negative direction removing the play from the differential system The rotate arm restricted by the sideframe could not follow the com pensating arm and the pressure on the rubber roller would be relieved allowing it to expand The play caused by wear in the system was just enough to allow the rubber roller to ex...

Page 45: ... five character is selected the rotate eccentri c arm wi II be restri cted from rotati ng about the pivot pin beyond the negative 4 position and the com pensating arm will then begin to rotate about the eccentric shou Ider on the rotate eccentric arm Since the center of the eccentric shoulder is lower than the pivot pin closer to the rotate link and the compensating arm pivot point is shifted betw...

Page 46: ... spri ng 1 the ro tate arm tends t o overthrow beyond the positive positi on se lected because of a momentum built up in the rotate arm tape system rotate pu Iley typehead etc This overthr w allows the V shaped wedging slot to open up resulting in unwanted roller droppage 37 Compensator Assist Spring FIGURE 96 Wear Compensator The compensator damper spring Figure 96 is a leaf spring designed to ab...

Page 47: ...a clockwise negative direction when the comparison is made Fig 98 The typing element is homed to the rotate selection that wi II coarse a lign the most positive with respect to the rotate detent when the head play is removed in the negative di rection It is IIhomed so that this rotate selection will de tent 010 to 020 on the negative side of the detent notch when the head play is removed in the ne...

Page 48: ...the print shaft Each cam is secured to the sleeve by set screws On present production pri nters the detent and ri bbon feed cams are one cam The cam at the left is the ribbon lift cam It is set screwed to the print sleeve causing the cam to rota tE with the sleeve The set screw mounting also prevents the print sleeve from shifting toward the left The CClm at the right is a double cam called the pr...

Page 49: ...tending between the side frames is the anvi I It is an angle shaped bar with the lip extending to the rear As the FIGURE 103 Anvil And Striker 40 typehead embosses the paper to the correct depth the stri ker hits the bottom of the anvi I and prevents further travel of the rocker and typehead This means that the impression for each character will be consistent with little variation between the char...

Page 50: ...ism is to provide a lighter impression for the pe riods commas colon semi colon quotation mark apos trophe hyphen and underscore regardless of where the im pression control lever may be set Before going into any detai I on the impression control mecha nism it is necessary to first understand how the automatic ve locity selection mechanism operates since both mechanisms are directly related Automat...

Page 51: ... from the bottom of the ma chine by the yoke actuati ng lever spring This spring ten sion positions the roller directly beneath the high velocity lobe of the print cam as shown in Fig 105 4 41 1 Yoke Actuating Lever Tab Cord Anchor Bracket I Velocity Contro l Cable I I __ I I 1 I I l l ZC 2200r0 2 J FIGURE 105 4 Yoke Actuating Lever And Spring A sheathed cable called the velocity control cable fas...

Page 52: ...the adjustable stop and anchored to the latch mounting stud spring loads the follower in a clock wise direction The velocity control cable is hooked to the lower extension of the follower The upper extension of the follower is spri ng loaded against the low velocity cam which is a double lobed cam set screwed to the right end of the fi Iter shaft directly to the left of the shift interlock cam Fig...

Page 53: ...he print cam is leaving or approaching its rest position Print Cam Print Cam Follower And Roller FIGURE 105 10 Print Cam Follower Stop Screw The velocity control cable consists of a thin strand of wire with eyelets at each end running through the center of a flexible plastic coated sheath The wire slides freely within the sheath transmitting motion from the low velocity cam fol lower to the yoke a...

Page 54: ...ocker Restoring Spring Print Cam Follower FIGURE 105 15 Impression Control Mechanism Changing the position of the impression control lever causes the pin on the lower portion of the lever to move forward or back to a new position in the forked slot of the print cam fol lower Fig 105 15 Just as in the early style print mechanism the front to rear position of the pin determines the amount of powered...

Page 55: ...e escapement mechanism Pivoting on the same stud with the escapement pawl are the backspace pawl the tab lever and the tab lever trigger The tab lever latch mounts on the right side of the escapement bracket 41 5 5toP lug Escapement Pawl Escapement Rack Fi Iter Shaft Eccentric Collar Escapement Cam Follower FIGURE 106 Print Escapement Mechanism The escapement pawl contains an elongated hole at its...

Page 56: ...ove during an escapement operation This could cause partial or half spacing as the two pawls would alternate holding the carrier during an es capement operation The backspace and escapement pawl are pinned together so that they will always move together laterally but front to rear independently The reason for this is covered in the backspace mechanism Torque Bar The torque bar is a flat bar that p...

Page 57: ...g especially onl2 pitch machines To insure that the torque bar can restore quickly enough the trigger is disengaged from the torque bar lu just after the escapement trip occurs The operational latch bracket is formed to the rear at the right side Attached to the inside of this rearward portion is a small plate called the trigger guide Fig 109A The trigger guide has a stud extending to the left jus...

Page 58: ...s on Iy a sma II eccentric co liar on the pivot pin Fig 106 prevents the pin from bowing forward due to the pull of the escapement trip link The collar braces the pivot pin by resting against the bracket in which the piv ot pin is mounted Without the collar some of the trip link motion wou Id be lost in the flexing of the pivot pin Escape ment fai lure would result if not enough trip link travel r...

Page 59: ...cord This in turn rotates the escapement shaft enough to keep the carrier re turn cord tight OPERATIONAL CAMS AND CONTROL MECHANISM All powered service operations are driven by the operational cam shaft located on the right side midway back in the ma chine The powered operati ons are the spacebar backspace tabulation carrier return indexing and shift The spacebar backspace tabulator carrier return...

Page 60: ...nto engagement with a tooth of the clutch ratchet by 46 Operational Control Bracket Lug FIGURE 115 Clutch Pawl Being Disengaged merely rotating the clutch wheel out of the way As soon as the clutch release arm is allowed to restore it is pulled by its spring back up into position to contact a tooth of the clutch wheel There are only two such teeth for the double lobed cam and on Iy one for the sin...

Page 61: ...n for both cam control mechanisms is the same however the parts design differs slightly Keylever Pawl GUide Bracket Interposer Cam Follower 1 Interposers Each mechanism operated by the cams requi res an interposer to select the mechanism to be operated and to cause the cam to be engaged These five interposers operate front to rear through slots in the operational control bracket and are latched fo...

Page 62: ... operates the indexing mech anism Each time the cam operates an indexing action oc curs A return spring in the indexing mechanism restores the am follower and holds the roller against the cam The backspace spacebar tab cam follower is designed to op erate th ree mechanisms Because it has three positi ons to operate the cam follower must be wider than that of the car rier return An extension spring...

Page 63: ... the cam Movement of the cam follower pulls down on the op erational latch to power the mechanism and at the same time actuates the interposer restoring lever to restore the interposer forward The clutch release arm restores into the path of the clutch wheel ready to disengage the cam clutch The cam follower passes the high point of the cam and re stores to the rest position as it reaches the low ...

Page 64: ...lower end has two eccentric pins that serve as contact bai Is Fig 125 The pin on the upper end of the arm rides underneath the op erational check pawl As the cam rotates the check pawl rides out of the notch in the check ring Fig 126 This causes the check pawl to move down pushing the top of the actuating arm down The actuating arm pivots on the shoul dered screw raising the lower end As the bail ...

Page 65: ...ig 127 1 FIGURE 127 1 Operational Contact Block Assembly The contacts are normally closed contacts held open by an actuator As the actuator moves outward the contacts are permitted to make Fig 127 2 There are two contact actuating bai Is One is operated by the carrier return index contact actuating cam and called the right hand contact actuating bail The other is operated by the backspace spacebar...

Page 66: ...ear of the actuating arm will move upward This will pivot the actuating bail away fromthe contact block assembly and permit the actuators to move toward the front of the machine Only the unlatched actuator will move far enough to transfer the contacts The remainder of the actua tors wi II be held by their respective latches As the opera tional cam continues to rotate the cam follower will be drive...

Page 67: ...nism provides the operator with a means of moving the carrier to the right one space at a time with out typing a character on the paper It is used mainly for spacing between words but it maya Iso be used to space the carrier quickly to any point toward the right on the writing line The spacebar operates by tripping the escapement pawl and backspace pawl out of their racks as on a print escapement ...

Page 68: ...e removed from their racks and an es capement operati on takes place Spacebar Stops Two styles of final stops have been produced and used on the 52 early style spacebar mechanism Both styles attach to the middle of the keylever guard at the front of the machine and function by blocking the downward travel of the spacebar stem Fig 130 Upward travel of the spacebar is limited by the spacebar stem A ...

Page 69: ...storage feature greatly re duces the possibi lity of spacebar fai lure during a letter space letter operation Failure results only if the spacebar opera tion is not stored The spacebar will fail to store only if the spacebar and letter keylever are depressed simultaneously Spacebar storage is accomplished by blocking the rearward movement of the spacebar interposer The interposer travel is blocked...

Page 70: ...interposer wou Id interrupt and store the rear ward travel of the spacebar interposer unti I the fi Iter shaft completes its cycle At this time the spacebar interposer would be released to finish its rearward travel and the space bar operation wou Id complete Note that the interlock inter poser is spring loaded into its active position and powered to its rest position This is to prevent breakage s...

Page 71: ...t movement of the backspace pawl to the left also moves the carrier and escapement pawl to the left Fig 136 The tip of the back space pawl engages the teeth of a sliding backspace rack lo cated on the back of the power frame just below the escape ment rack Movement of the backspace rack to the left forces the backspace pawl to the left to cause the backspace opera tion Escapement Torque Bar Backsp...

Page 72: ...erposer Depression of the keylever causes the interposer to be released to the rear to begin the operation The upward travel of the keylever is limited by a fu Icrum rod located at the top of the gui de comb The final travel of the keylever is reached when the keylever bottoms in the guide comb CARRIER RETURN 11 Inch Printer The carrier return mechanism provides the operator with a powered return ...

Page 73: ...down on the latch It also pulls down on the index pawl carrier link attached at the rear of the follower causing a line space operation The carrier return operational latch is mounted on the carrier return latch arm that pivots around a shaft on the operational latch bracket at the rear of the powerframe Fig 140 The shaft is called the pivot pin and also acts as a pivot point for the escapement tr...

Page 74: ...he carrier return shoe holds the shoe away from the clutch spring in the rest position Fig 141 The clutch latch does not hold the cam follower in the active position during a return operation therefore the cam and fol lower immediately restore to the rest position ready for the next operation Depression of the keylever with the carrier in motion releases the interposer to cause another carrier re ...

Page 75: ...return operational latch is pulled down by the cam follower the latch arm presses the carrier return lever down A stud on the carrier return lever fits in a slot of the intermediate latch actuating arm and as the lever moves down it rotates the arm and pivots the carrier return latch pin and dutch latch As the carrier return latch moves downward it rotates the latch actuating arm which contacts th...

Page 76: ...ng carriage machines as on the short carriage CARRIER RETURN LATE STYLE The carrier return operation remains the same Parts have been re designed to provide easier accessibility for adjustments and will hold these adjustments longer The transfer of motion has changed in the operational latch mechan ism Fig 145 1 When the carrier return operationaI latch is pulled down by the cam follower the latch...

Page 77: ...s the carrier to move to the left margin whereas depressing the index keylever not used on some printers causes a line space operation only The index selector lever located to the rear of the right end of the platen may be positi oned so that the mechanism wi II space either one or two spaces during each operation With the lever forward sing Ie line spacing will occur Double spacing wi II take pla...

Page 78: ... of multiplying the leverage must be uti lized The index pawl carrier link is attached to the front of the index multiplying lever that pivots at the rear of the cam foil ower Fig 151 A lug at the rear of the cam fol lower prevents the multiplying lever from pivoting up in front During a single line spacing operation the multiplying lever moves down the same amount as the cam follower Fig 151 When...

Page 79: ...het teeth to lock the platen in position Fig 155 If only a single space operation is desired the index pawl must be prevented from entering the ratchet unti I it has passed one tooth of the ratchet The remaining travel after the index pawl enters the ratchet is only sufficient to cause one tooth of rotation to the platen The index pawl contacts the platen overthrow stop at the end of the stroke as...

Page 80: ...g either the index or carrier return interposer to the rear 62 The carrier return operation has been discussed in another sec tion therefore the index alone will be dealt with here The index keylever pivots on the keylever fu Icrum rod at the rear and extends toward the front on Iy to the fi rst row of keybut tons An offset in the key lever places the end of the key lever and keybutton outside the...

Page 81: ...nism connects the ratchet to the platen so that it can be engaged for line spacing and disengaged for the variable operation The clutch can be disengaged by pushing the right hand platen knob toward the left As long as the knob is he Id to the left the platen can be rotated free Iy while the ratchet remains stationary When the knob is released the clutch is automatically re engaged by spring tensi...

Page 82: ...D CLEAR POSITION FIGURE 161 Tab Set And Clear Operation Tab Set and Clear Gang Clear Both the tab rack and the tab clear mechanism has been re designed on late level machines so that the tab stops may be gang cleared Gang clearing tab stops is the term given to the procedure for clearing all of the set tab stops in one oper ation This is accomplished by positioning the carrier at the extreme right...

Page 83: ...ed rather quickly when released and has a tendency to flip past the rest position This could partially Contact Operating Lug Early Style Tab Rack FIGURE 163 Gang Clear Finger clear a stop that had just been set or partially set a stop that had just been cleared To prevent the rack from restoring past the rest position a leaf spring at the left end of the rack applies a slight braking action Fig 16...

Page 84: ...t in front of the center section of the power frame The right hand dust shield has been redesign ed so as not to interfere with the mechanism The tab operational latch is connected to the tab lever arm and bearing assembly As the latch is carried down by the cam fol rower the tab lever arm rotates in a counterclockwise direc tion pushing up on the tab link Fig 165 1 The link con nects to the tab b...

Page 85: ...ssembly to hold it to the rear tl us latching the pawls out of their racks Fig 167 A torque bar lockout tab on the tab lever holds the torque bar to the rear as long as the tab lever is latched out Fig 168 This is necessary to keep the tab Interlock contact operated for the duration of a tab cycle Tab Torque Bar FIGURE 167 Tab Latch Operation Early Tab Lever FIGURE 168 Torque Bar Lockout Tab Early...

Page 86: ... to speed up and tighten the clutch spring The mainspring then tries to accel erate the operational shaft The mainspring does not have sufficient tension to drive the operational shaft because of the drag present in the system The shaft must be driven by the motor therefore the speed of the tab governor pini on can be no faster than the normal speed of the operational shaft The escapement cord dru...

Page 87: ...er trigger restores the tab lever is allowed to reset for the next operation As the trigger moves out of the notch in the tab lever the tab lever is snapped to the right by its spring into position to be operated by the trigger At the same time the tab lever lug resets to the right in front of the escapement pawl ready for pawl release on the next operation A forward extension of the tab lever res...

Page 88: ...d in the same place as the old style interlock The main difference is the manner in which the contact is trans ferred As the tab torque bar is rotated the tab arm Fig 176 moves upward pulling upward on the trigger lever Since the torque bar rotates through an arc the trigger lever wi II cam off the tab arm However the trigger wi II be in contact with the rear side of the tab arm and wi II be camme...

Page 89: ...nd margin on the paper With the keyboard locked the operator cannot in advertently continue typing at that position The line lock mechanism is operated by the right hand margin stop In addition to operating the line lock the margin stop also rings a bell several spaces before the line lock action oc curs The bell warns the typist that the carrier is near the margin stop In most cases this allows s...

Page 90: ...eylever rotates the margin rack to move the bell ringer bellcrank out of the path of the line lock bracket This allows the line lock parts to restore to rest unlocking the interposers The keyboard lock interposer is restored up and to the rear by an extension spring the same as a character interposer The stud on the interposer extends to the left under the keyboard lockbellcrank in position to res...

Page 91: ...ed to restore the bai I lever resets above the bell clapper bellcrank ready for the next operati on Bell Clapper Bellcrank f Bell FIGURE 182 Bell Ringer Mechanism 72 Margin Release The purpose of the margin release m echanism is t a low typ ing on either margin of the paper without reposltlo lng the margin stops The margin release operates by rotating the margin rack so that the margin stops move ...

Page 92: ...nism operates in the same manner as the old style The major difference is the use of a snap action switch in place of contacts Fig 186 73 Contact alP Contact Note The Backup Spring Should Be Formed to Touch the Actuator With All Parts At Rest Carder Away From the R H Margin FIGURE 186 Last Column Contact Late PAPER FEED AND RELEASE MECHANISMS Paper Feed The purpose of the paper feed mechanism is t...

Page 93: ...ark in the middle at the top of the card holder indicates the middle of the next character to be typed Above the writing line the paper is engaged by two rubber rollers mounted on the paper bai I These rollers hold the paper against the platen above the writing line so as to re duce the possibi lity of overprinting on the paper The rollers FIGURE 188A Standard FIGURE 188B Pin Feed FIGURE 188 line ...

Page 94: ... Fig 189 2 Insertion of paper in the printer will cause the leading surface of the paper switch arm to rotate to the rear The rear tab of the arm raises and allows the microswitch to operate Re transfer of the microswitch takes place when there is insufficient paper in the printer Paper Switch Arm Tie Rod FIGURE 189 2 Paper Switch Assembly Side View I A switch lockout bracket can be used to inh ib...

Page 95: ...nism moves the ribbon laterally past the printing point to provide an unused portion for the next typing operation It also reverses the feeding direction when the end of the ri bbon is reached The ribbon is a 9 16 fabric ribbon enclosed in a disposable cartridge unit for clean handling The cartridge unit con tains two spools on which the ribbon is wound The ribbon is constantly fed from one spool ...

Page 96: ... positions which may be selected by the operator The ribbon lift control link is attached to the ribbon lift control lever pivoted under the front of the carrier casting Fig 192 The control lever is spring loaded to the rear against a stud on the ribbon lift lever The ribbon lift lever has a button lo cated just to the left of the carrier pointer Moving the but ton to the left causes the stud on t...

Page 97: ...tion The detent pawl must be disengaged from the supply side in order for ribbon feed to occur Each detent pawl has a long curved extension resting against a roller on the ribbon feed detent tever Fig 193 When one detent pawl is engaged with its ratchet the other is disengaged depending upon the posi ti on of the ribbon feed detent lever Two flat springs are mounted to the ribbon feed plate at the...

Page 98: ... spool As the feed pawl restores its spring pivots it over into engagement with the opposite rat chet FIGURE 198 Ribbon Reverse Interposer And Lever The purpose of the interposer lever is to prevent the motion of the ribbon reverse interposer from being choked off during a reversing operation by the ribbon feed pawl if the feed pawl shou Id become trapped between the ribbon feed ratchet and the in...

Page 99: ...oward the front of the machine and holds it there as long as the printing is to be done in red To print in black the cam follower latch must be free to be spring returned to the rear Because the cam follower latch is on the carrier the control for the latch must be movable This is done by looping a tape similar to the rotate and tilt tapes around pu Ileys One end of the tape is attached to the rig...

Page 100: ...ch revolu tion of the cam A shouldered rivet anchored to the feed plate passes through an elongated slot in the feed and reverse plate Fig 203 Th is rivet acts as a guide for the rear of the plate as it operates back and forth The front of the plate is secured and guided by a recessed pin that is riveted to a part of the reversing mechanism called the IIratchet detent leverll Fig 203 80 FIGURE 203...

Page 101: ...pool Ribbon Feed Pawl FIGURE 206 Ribbon Feed Pawl Transferred To L H Ratchet A small bellcrank mounted in the core of each ribbon feed ratchet acts as a sensing device to determine when the revers ing operation is to take place As long as there is ribbon wrapped around the core of the supply spool the ribbon will hold this bellcrank called the reverse trigger in its inactive position Once the last...

Page 102: ...bbon feed lever following the ribbon feed cam back to rest During a reverse operation the extension spring which loads the lower lug of the ribbon feed lever against the feed cam might not be strong enough to keep it against the cam during the restoring portion of the feed cycle If this should occur the upper lug Fig 202 on the feed lever will come in contact with the cam causing the feed lever to...

Search results

Summary of Contents for Selectric I/O

Reviews:

Related manuals for Selectric I/O

Brands by name

Popular brands

IBM Selectric I/O, Manual Of Instruction

Search results

Summary of Contents for Selectric I/O

Reviews:

Related manuals for Selectric I/O

Brands by name

Popular brands