Manual / Guide · 1951
Description of Operation of No 15 Teletypewriter Bell System Practices Section P70 013 1951
Description of Operation of No. 15 Teletypewriter
Manual / Guide · 1951
Description of Operation of No. 15 Teletypewriter
A.t.. ;3c:n ~~ e tiBELL SYSTEM PRACTICES Transmission Engineering and Data Telegraph Stations and Loops SECTION P70.013 Issue 1, October, 1951 AT&TCo Standard 15 DESCRIPTION OF OPERATION OF NO. TELETYPEWRITER ( [ (' This section describes the operation of the No. 15 Teletypewriter. It has been is sued principally for use in training Bell System teletypewriter repairmen. It is reproduced from material originally prepared for other purposes with such modifications as seem desirable to facilitate its use in conjunction with other Bell System practices in the proposed training work. The basic operating principles are described but no attempt has been made to include recent improvements and changes. INDEX DESCRIPTION OF THE MODEL 15 TYPEBAR PAGE PRINTER PAGE GENERAL •• 2 Keyboard Transmitter • • • • • Signalling Code S/NQ.E-Ptlt/BLE L/NE rEEtJ LEVER 2 2 7YP4"4/9R ~/9RRU?vi #,IIA/t/,ll,t. ~-"RR14trE RETt/RA/ tPcA"$,4R .PU#A:?T LEYER t!" ~;f/£,F ( I.HF----~ l (b .:fi!JVR -RECE/1/F 4RfAir M"C::W.W,.rN · tf:'iYidAR.P /LLt/~T47#2. This section contains material prepared by the Teletype Corporation and it is used with their permission. Printed in U. s. A. Page 1 SECTION P70.0l3 CHARACTE~ ~!AlE 5EtVT S!(;NAI..S . .. . PAGE Carriage Return Figure Shift and Letter Shift 15 ~ 14 ~-::..: INDEX (Cont 1 d) TYPING UNIT Func.tions 4 • • • • . . . • . . . . Keyboard Locking Mechanism • Line Feed Function • • • Locking Cam • • • . • • • • • • Locking Function Lever • Main Shaft Assembly Main Shaft Clutch Throwout Lever • Margin Signal Bell • Motor Stop Function Printing • • • • , • Ribbon Feeding •• Ribbon Lockout , • Ribbon Oscillation • Ribbon Reverse • • Selecting Unit •• Signal Bell Function Sixth Vane , • • • Spacing , • , • Spacing Function Unshift on Space Function 16 19 18 7 8 5 8 12 19 8 12 14 13 13 5 17 16 ~ ~ ~ '-.1 ~ ~ A 8 '? -~ ~ (' /) $ E p 3 c & L H I .I K ) 11 21 N • MOTOR SPEED CONTROL - MOTOR GOVERNOR BASE UNIT •• 22 LINE TEST KEY • 24 24 LINE RELAY GENERAL The No, 15 Teletypewriter is a machine designed for interchanging messages between two or more points. A sending-receiving machine consists of a keyboard transmitting unit1 base, typing unit, and cover (Illus. 2). The keyboard transmitting unit is used to send electrical impulses of the five unit code to the receiving mechanism of the typing unit at any station. These received signals will cause the typing unit to type a copy of the message sent by the keyboard operator. Signalling Code The signalling code used to transmit characters is the "Start-stop," five unit code which consists of five selecting impulses used in various combinations of current and nocurrent intervals. Each group of five selecting impulses is preceded by a start impulse and followed by a stop impulse used to maintain synchronism between all stations on the circuit. Impulses which operate the selector magnets are known ·as marking and those which do not are known as spacing, Fig. 1 shows graphically the code used. Page 2 ') .. L 23 - • 8 10 ORIENTATION • C . __ I 17 17 22 ~' ~ ( SYNGHRONISM • '~ () p () R s T . (/ v w z X / z ,,6 I y ~IN£ F££0 I I .SPACE CAR. RET. I ~~~(l,e,:s i.£'TTE~.S • D • • ------ r:::. r· -------=- SPACIN~ IMPLI~SES ,ttARK!Nc:; IMPI/~SGS ,,_) Fig. 1 ' Keyboard Transmitter --~ The keyboard (Illus, 3) consists of a set of keys, keylevers, a bank of sending contact springs; operating cams, clutch and gear. This gear engages with the transmitting shaft driving gear (Illus. 4). The sending cams are normally held stationary because the clutche~ on the driving shaft are held apart by the clutch throwout lever. When a key is J SECTION P70.0l3 f r depressed the driven member of the clutch is permitted to move into mesh w~th the driving member causing the cam sleeve assembly to revolve. At the end of the revolution the driven member of the clutch is disengaged by the clutch throwout lever and the cams brought to a stop until the next key is depressed (Fig. 3). Beneath the keylevers are five selector bars and a universal bar extending across the width of the keyboard. The selector bars are provided with saw tooth shaped notches as shown in Fig. 2 according to the requirements of the signalling code. These bars rest on rollers and are guided at each end so that they may be easily moved endwise. When a key is depressed the keylever strikes the slanting sides of these notches moving the bars either to the right or left depending upon whether the impulses corresponding to the bars are to be spacing or marking impulses. The universal bar which is connected to the trip off pawl controlling the starting and -stopping of the sending cams is pivoted at its two ends in such a way that the depressing of any key moves it downward to actuate the clutch throwout lever. Thus, whenever a key is depressed the selector bars are set and the universal bar is moved down :('ermi tting the sending cams to start rotating lFig. 3). Each selector bar engages a vertical locking lever at its right hand extremity and positions it to correspond with the signal impulses to be transmitted (Fig. 2). Each locking lever controls the motion of a contact lever by either allowing the contact levor to close its contact when the cams revolve or restricting the motion of the contact lever. If the upper end of the locking lever is positioned to the left corresponding to a spacing impulse, it engages the contact lever and prevents it from rising into the indent of the cam as it rotates, thus holding the circuit open for that impulse (Fig. 2-A). If the locking lever is positioned to the right corresponding to a marking impulse it cioes not interfere with the movement of the contact lever (Fig. 2-B). Then as the cam revolves the contact lever rides on the cam surface and rises into an indent thereby allowing its contact to close, sending out a marking impulse~ As the cams rotate the impulses, either marking or spacing, are transmitted in succession. The start-stop cam controls an addi tiona.!. contact lever which in turn actuates the start-stop contacts (Fig. 3). These contactf are opened at the beginning of each revolutim of the cam shaft to transmit the start impuls• ,__----~~Tt::"H IWRdW.aetr ££YEK ~ Lal,P t::"A'N - - - - - - - - - - - - - - . . I.P~K LPd.P .Q;fR/-f/i:P C'#N tri9N 1"-U'd.E # 5 1 " E N & r - LINE TE5.T KEY - - - - - . . . _ ( { C'PA?"At:"T.t:R-'ER5 ~~/,PR/AV41"--------~ Ki'YUI"ERf A"EJ"&?#R~ /LLP.F/RA'T/.:?,4/ f. Page 3 SECTION P70.0l3 C.?/V.TK.T C~ --~ CtWT.-90" tEffR--<i'\ Cat'TIICT CIIH---------, l...._ CtWli'i'CT .J"I'1PI#GSSi~~ ~. LX-o'#G LEYER--KEY /.EYER ~. J1A"J',"--'."-/V'~-J'J\_ (itt) ··~ "'=-sELECTOR $!'9R Fig. 2 LcJC~Lc/cJ~ tr~~·-----------------------§m.RT-S7i?~ C/IM T#ROJ1/·tJUTC/?l'f ~ U' c~~ 5LEEJ/E A'~EMBLY: ,, CZG/TCh" 7h'Rt7J1/·0G/T L E V E R TR/POFF PAWL 5P-'?CEREPEI7TROO n •n/ 5 ~~ ~ __ CL.t/TCH LEJ/ER PA'WL KEY---r-1 ~EYLEVER 5?..9CE ffYLEWR u ltf5FLECTOR B~ '-----t/MP'E~ BAe (slf ILLI/STRI?TION .1) Fig. (spacing) and remain open during the transmission of the five impulses. After the :fi:ftll. impulse has been transmitted, the start-stop contacts will again close sending the stop impulse (marking) to the line. These contacts will remain closed until the next keylever is depressed. At the end of the revolution the clutch driven member is cammed out of mesh with the driving member and prevents the cams :from rotatin,c; :further until the next key is depressed. The lock loop which is raised by the lock loop cam at the end of each revolution to allow the new combination to be set up is used while in its down position to prevent a change in the selection set up (Illus. 3). This is done by holding the locking levers in their set positiqns while the signals are being sent out. This arr&~gement also makes it impossible to depress another key until the signal for the previous character has been transmitted. The keyboard is equipped with a0pace repeat device which permits the transmission of continuous spaces. (Illus. 3.) When the space keylever is depressed, the space repeat rod attached to the keylever extension will move the clutch lever pawl :forward in turn holding the clutch throwout lever out of Page 4 3 engagement with the projection on the driven clutch. Thus the transmitter cam sleeve will be permitted to revolve continuously until the space keylever is released. TYPING UNIT The type bar carriage of the Model 15 typing unit consists of typebars similar to those of a typewriter together with other associated parts. The typebars are mechanically thrown against a platen causing letters to be printed. The typebar to be selected is determined by the setting of five code bars which are actuated by line signals through the medium of the selector mechanism. The code bars are so arranged that the notches on their upper sides will be lined up permitting a selected pullbar to move down into the path of the pullbar bail. This bail move~ the pullbar forward causing the typebar to which it is connected to strike the platen. Illustration 2 shows the typing unit mounted on the base with a keyboard. The various functions; line feed, space, carriage return, figure shift, letter shift, etc. are also accomplished mechanically. A . ) ~t< \., ,,,.~ S~ION P70.0l3 .n'At::"l70N B/1/L CIJ.M -----... PR!WJ7NG BI?IL ~AM'----, SP~C/NG" .5~.P5LEEf/E ~------------------- ( ~RK~OND/SC - M/1'/A/ .Sh'r:!FT GEifR STaP r Mt91N SJ.Ifif"T B&h'R..WG---' Nlf!N SN,t;,rl" CLI/TCII Sl'lfC/Aiti E5C.41'EM!'NT RIITCII£.'7"-----' M.41AI Sfllf,rT SP17'C!N<:r dEifR _ _ _ _ _ _____; OIL f'LI/G S'!llfi"T 8EfiRitVu MI7'1N SII17'~T TRfiAIS#/.TJi'A/6 SlllfFT t'R!WIYG GE!lR IYI91N SlillrT 115S&.MB1.Y /L.L.I/STRIYT/dlv' .P, motor drives the main shaft assembly of the typing nni t which supplies power to all me chan .. ically operated parts. Main Shaft Assembly (Illus. 4). The main shaft gear is located near the right end of the shaft and meshes with the mo .. tor pinion. Thus it may be seen that the main shaft will be caused to rotate continuously during the period the printer is in operation. The main shaft also operates the keyboard cam shaft through the medium of the transmitting shaft driving gear. ( ( The main shaft spacing gear meshes with the spacing shaft gear to provide the spacing action at the required time (Illus. 8). The spacing escapement ratchet, sleeve and friction discs are associated with the spacing mechanism and are described nnder "Spacing." The function bail cam and the printing bail cam operate their respective bails. The main shaft clutch is used in conjunction with the selector to provide power to operate the printing and function bails immediately after the selection has been completed. The selector cam sleeve is fitted over the left end of the main shaft and is driven through the medium of a friction clutch. Selecting Unit The purpose of the selecting unit is to receive the signals from the transmitting station, distributing them mechanically, there.:. by setting up various combinations on the vanes. These combinations will determine the character to be printed or the function to be operated. The selector mechanism is controlled by the magnet which receives the code impulse from the line. Normally the armature of this magnet is pulled up and the stop arm is against the stop lever which in turn is held by the trip latch. Because the stop arm which is a part of the selector cam sleeve is engaged with the stop lever, the cam sleeve is prevented from revolving (Fig. 4). When the start impulse which is spacing (no current) is received the armature is released and pulled away from the magnet pole pieces by the armature spring. This will move the trip latch out of engagement with the stop lever thereby releasing the stop arm allowing the cam sleeve to revolve with the main shaft. Each vane is operated by a selector cam through a "T" lever, a sword and a selector lever (Fig. 5). For instance, suppose that the code for the letter "E" is received. Upon the reception of the start impulse (a no current impulse), the armature moves away from the magnet, imparting motion first to the trip latch plunger (Fig. 4), which in turn causes the bell crank to move the trip latch out of engagement with the stop lever releasing the stop arm as explained previously. The selector cams start to revolve and the number 1 selector cam engages number l selector lever. Page 5 SEC!ION P70.0l3 ADJUSTING SCR£W - - - - - - - - - /"-"-- 8/i.ACK&T #CC£NT~!C ARMATURE eXTENSION BRACKET LINK SWOROS (S) AteMATURE?' BRACKET .SC~&W.S ~ ARMATUR£ BRACKeT - - - - - - - - . .SPAC/N!S 5TOI" 5C~EW - - - - - - - - - - . , MARK!N6 5 TOP !VV'T_ _ _ _ _ ____ "T"u:veRs ARMATURE - - - - - - - - - - . . . . . _ MAGNeT COI<::::Ec_ _ _ _ _ _ _ _ _ __ ') MOTOR STOP PAWL MAGNET-------MAGNET SleACKET MAGN£T BRACKET MOVNnN6 STOP LEVER BACK STOP SCREW SCREWs--~- PIVOT SCIC£W 1""/NDeliZ ASSEMBLY Tli2/P OFF ECCENT!!IC .SCREW _ _ _--/ TRIP LATCH PLUNGER STOP REJ../5AS!£ LEVER SELECTOR UNIT /LLUSTRATION-5 STOP LEVER ECCENTRIC SCREW T!itiMB SCREW ~-----------~Lr~n11~£T ~ TRIP L/ITCH I'LI/N6ER BEii /'PANK'- ~ ;€ 'J1 iiVi /IRII.I?TIH' ;f"A'TE,..Y5/a¥ ) CL1'9MPING I'LI?TE-TRIP LllTCH~-- 11RN a'/IHP~ 5CPEN/ '---------S~LEYER •IG&I -. . . . . RAWGE SCI'?LE----------~ (SE£ lttV6Tifii/IT/ONS) Fig. 4. Page 6 i("" I.~Y&I't' l'"/'.rAirPN"' KREll' ~,J SECTION P70.0l) (' r when the firQt impulse of the letter 11E11 (Mark<i!i ing or current impulse) has been recoind by the magnets from the line. The magnet armature is tlierefore pulled up, bringing the upper end of the armature extension up into the path of the upper !fword arm. When the D.l.lliib_er 1 cam passes the number 1 selector lever; this lever is rotated counterclockwise, carrying with it the sword, which strikes the upper end. of the armature extension and is in turn rotated clockwise about its pivot, point A. This positions the sword so that when the number 1 ca:m clears the selector lever, the selector lever spring moves the sword against the 11 11 T lever and brings the front edge of the number 1 vane down. As no current is received while number 2, 3, 4 and 5 cams are passing their selector levers, the magnet armature is released and the armature extension moves down so that the lower end of the armature extension is in the path of the lower sword arm (Fig. 5). As the number 2, 3, 4 and 5 cams pass the number 2, 3, 4 and 5 selector levers the number 2, 3, 4 and 5 vanes are moved so that the front edges are up. With the front edges of the vanes in the upper position the corresponding code bars will be moved to the right orunoperated position through the medium of the bell cranks (Illus. 2). With the front edges of the vanes in the lower poaiticm the corresponding code bars will be mov•d t01 the left or operated positionWith the AlUI.ber 1 code bar to the left and number 2, 3, 4 and 5 code bars to the right, there is a notch in eaoh code bar opposite. the "E" pullbar. The sixth cam releases the main shaft clutch allowing the printing and function bail to make one complete revolution (Fig. 8). The printing bail cam will permit the printing bail to be pulled forward by its spring. The "E" pullbar will be pulled down by its spring into the path set up by the code bars and the pullbar bail, actuated by the printing bail, will carry the pullbar forward causing the type bar to strike the platen printing the letter 11E11 (Fig. 9). Locking Cam The locking cam has five low and five high portions on its periphery against which the locking lever is held by its spring (Fig. 6). During that part of each impulse when the swords are set by striking against the armature extension (at the time the peak o:f any selector cam is operating the corresponding selector lever) a low portion o:f the locking cam is opposite the locking lever. The armature .Rn1e.IJ A?RN..F--- ~---...!'T"'LD'ER I /IRNATI./RE- - - - ~~---- 5'ELECTtJR MA&NET- ~B" • ~'--~~--S"IfltJRO '------:4' SELECTOR CI'JM '------5ELECTIJR LEYER ($"EE /LLVS"TRAT/OA/ S.) Fig. 5 (_ La'"..t?"N6 WEaE 5/VtJR/J ,4R,A1~------~--- -1?9/VE -------- ----~~--"r£EYER /WMI"?Tt/RE EXTEN5/tW--- -- - - - - - - - - - - ~WtJRP ( LOCK/N6 C11M-~------ LdCKI~ lEJ/ER --------------~LP~#v~~£RF~RI¥v {.FEE /LLVS"TRAT/OAIS) Fig. 6 Page 7 SECTION P70.0l3 will now be he14 tiJ'Jily in podticm 'bf the "lV' ehaped extension ot the loo~ lner encagiq the looking wedge on the armature extension. When the locking laTer is riding on the high portion of the looking cam the looking lever extension will be held a.wq from the looking wedge and the armature will be free to move in re•ponse to the next impulse. Looking Function Lever It is obvious that the vanes are held in their selected positions until the printing of the character has taken place. This is accomplished by means of the locking function lever. The locking function lever is the first on the right of the function levers, which are located immediately behind the vanes (Fig. 7). When the printing bail is in its rear position, the function lever bail, mounted on the printing bail casting, is holding the locking function lever away from the vanes. When the printing bail is permitted to move forward, the function lever bail roller moves down, allowing the function lever spring to pull the lever against the rear edges of the vanes. The locking function lever will engage each vane, whether its rear edge be raised by a marking impulse or brought down by a spacing impulse, locking the vanes in their selected positions. The operation of the remaining function levers is dealt with under "Functions." Main Shaft Clutch Throwout Lever As previously described, the sixth cam on the selector cam sleeve releases the main shaft clutch allowing the printing and function bail cams to make one complete revolution (Fig. 8). At the end of each revolution of the printing and function bail cams the clutch stop arm engages with the projection on the driven clutch member and cams it out of mesh with the driving clut~h member. Immediately after the fifth impulse has been received the peak of the sixth cam strikes the clutch throwout lever cam arm moving the lever stop arm out of engagement with the projection on the driven clutch member. fhi• will permit the spring to move the driven clutch member in• to mesh with the dri Ti:ng member. Thus it aJ be seen that 'immediately after the completion of the selection of any character or function the printing and i'unotion bail cams will be permitted to revolve one revolution which will effect the printing of that character or the operation of that function. From the foregoing it may be seen that any character or function may be selected while the printing of the previous selection is taking place. ") Printing The printing bail operating arm is mounted on the bail mounting shaft on which is also mounted the printing bail, function bail and spacing escapement pawls (Illus. 9). The printing bail spring attached to the righthand end of the printing bail casting holds the printing bail against the upper end of the operating bail arm and the operating arm roller against the printing bail cam on the main shaft. Thus it will be seen that the printing bail cam will determine the position . of the printing bail at all times (Fig. 9). '') The actual printing of any character is not caused directly by xhe printing bail, but by the pullbar bail which it controls. The pullbar bail is attached to· the pullbar bail plunger on the lower surface of Which is attached the plunger roller (Illus. 6). This roller (when the typebar carriage is in place) is located between the printing bail blades (Fig. 9). This arrangement will permit the carriage to move from left to right and also allow the pullbar bail to be moved backward and forward by the printing bail regardless of the position of the typebar carriage. At the end of each revolution of the printing bail cam, the printing bail operating arm roller will be on the high portion of its cam (Fig. 9 & Illus. 9). The printing bail will be in its rearmost position, carried there against the tension of its spring. ··)·· .. ~-::;;;, , r-------t"UVC7701V i.EY'ERP'IIIL RrJii.ER mNES REI9R hlR'M· txt'M I'U\0/a\1 L.fVCR Sffll\t1 ~ Fig. 7 Page 8 Lc?CA?'NG ~tiNCli't:'!V LEVER J 0\ Q) l SECTIOII P10.01.3 As the printing bail c~ revolves, clear the code bars so that they are free to move in either direction. The combination for the succeeding letter then takes its place in the code bars and the printing operation is repeated as described in the foregoing. the roller on the printin~ bail operating arm will move a::;ainst the low portion of the cam. The printin:-; bail will ·follow the upper end of the operating arm, being pulled forward by its spring, and will move the pullbar bail forward. The forward motion of the pullbar bail will first allow all of the pullbars to be pulled down against the code bars by their respective springs, the selected pullbar being pulled down further than the rest, into the path set up for it in the code bars. As the pullbar bail continues on its forward stroke, it will enga:e the notch in the selected pullbar only, (the remaining ones being too high for their notches to engage), and carry the pullbar forward, throwing the typebar which is geared to it against the platen printing the character. Fig. 9 shows a cross-section of the typing unit. Spacing ., .. On the Model 15 Printer the typebar carriage is moved to accomplish the spacing. The typebar carriage is supported on two tracks. The upper track is arectangular rod and is located to the rear. The lower track is a circular rod and is located above the vanes (Fig. 9 & Illus. 7). The typebar carriage is moved by the spacing gear which is meshed with the spacing rack and is facilitated by three carriage support rollers, two of which operate on the front track and one on the rear track. The front track is slotted throughout its length, so that the heads of two carriage guide screws located at either side of the carria2;e casting, will be guided therein (Illus. 6). The operating arm roller will again ride up onto the high portion of the printing bail ca..'T! as it completes its revolution. Thus the operatin:; arm brings the printing bail back to its rearmost ~osition and in turn the pullbar bail which is engaged in it. When the pullbar bail is in its rear position all of the pullbars are moved by it 2ufficiently high to .,, The spacing rack is mounted on the rear of the typebar carriage casting and meshes with the spacin;_; gear which -is fastened to the upper end of the spacing shaft (Illus. 8). ,.:>_,;,.oER 5Tf'A'/5~/"£1:FR R.:'.c' ~PL4TE!f' ./ URR/A'5E f?'/"?~R/ RP'LLE.f'------------... // -~,.:>REffvRE R~L£ER5 /-R/6'6'~A/ .F.Pa:'L / ~ .6'.19/f' 4'4/L .P£tl#~ 5PArA6R~~-~~------------~~~ fPA'C/~iF :5~,4.:7 -------~ #.19$ .£¥#-'"/ IFEA'R .P,ei#I//1/IF ,) _,.hid a'.M-- - .F~A/F .F#.-;.-rr IFFI'fR------- CA'RRHIFE RE/vR# CZv/Jt"H·-------...._ t".I9RR/Ad"E RF!"tiR# t?I"FRA/7/W LEJ/ER-- ~PR&'T/#v .6'#/L &?.PER#T//YII" #R.N CIIA"RHtS"F R£/"t!RAI .rltiTC/r" .:.:?RK- - 't-,;:"U...VL'"TU?N £FffR .6'.194 RE5E!" 4'1'fR ·-- · -PR#VT/#F .6'.19/L ~R/45"£ RE/t!R# .tAT.?/1 4'1'fR · .6'4/L .Mt.?tiA/T&'F 5~T ~RR~tS"E RF!"t!R# -""ti#CTtt?# il"VER-..-t.J · · -.-rvAICT/&:W .6'#4 Fig. Pa::;e 10 9 ~~ SECfiON P70.0l3 ( ( The· spacins ehatt gear 1e located at the lower end of the spacing shaft and meshes with the main shaft spacing gear. The lower half of the carriage return clutch is fastened to the spacing shaft (Fig. 9). The upper nalf of the clutch forms a sleeve on the spacing shaft tQ which the spacing shaft gear is attached. The carriage return clutch members are in engage• ment at all times except when the carriage is returning from the end of a line. The func• tion of this clutch is described under "Carriage Return." The main shaft spacing gear is a part of the sleeve of a friction clutch assembly. It consists of the spacing ball bearing screwed to the shaft, a spacing escapement ratchet, a friction disc and felt washer, a spacing stop sleeve and a clutch spring (Illus. 4). The main shaft spacing gear will revolve with the main shaft unless stopped by holding either the spacing stop sleeve or the spacing escapement ratchet. When the typebar carriage reaohea thel end of its travel at the right end of the printer 1 the right margin adjusting screw (Fig,j 10-A) moves the spacing stop lever into the. path of a projection on the spacing stop sleeve. 'l'hia prevent& ap&ei:cg at ~ end or :t_he carriage travel. The spacing escapement ratchet is regulated by the front and rear escapement pawls which are mounted on the bail mounting shaft. With the printing bail in its rear position, the rear escapement pawl is engaged in one of the teeth on the spaci~ escapement ratchet, holding the spacing gear sleeve (Fig. 10-B). As the printing bail starts to move forward the operating arm strikes the lower end of the rear pawl, moving it out of engagement with the tooth on the escapement ratchet. At the same time the front escapement pawl moves down against the escapement ratchet into the path of another tooth which it will engage after having traveled one-sixth of a space. The printing operation then takes place. Near the ...---Pit$11T Nh'A¥/N IIIJ./tiSTINtf SCR£~ rtJIF 8//Rl"M.WM.f'~ -APMI.l.'Nd' BIIIL _.-----819/L ~IV6 5/H'T ~----S~E~~-RI"~R J")I'M'~ SftiP L£119 •'2'. ~~.w .!'llllrT '------5;:¥/CE PIIJIZ -,...t".kt'NT '-------/'tiNCTION 8~/i '---------G?ArRIIli'NG 19RN 111) (SL'£ /tiPS""m:W 8) (2J) Fig. 10 ~ ( ~N8£li C/111 1£1.1. HIIHHI"RSAPIN6- ~ l'fii.P6W 11£tt P/IJII'L \ ~ '----HA&'N IIZL CAM SllllrT •H ~MVAaL------------~ --~--------------8£UH~~R ( (.sEE liiPST-PIITII7N8) Fig. 11 Pta&• 11 SBCD'IOB P70.013 R/4617/V .F..P'I717.t:F A'/8117# REI/ERIE A;#--.........._ T~EIAR5---------~ ,,~, .R$117# 17.F&/£.L.ATI7R R/8'#.?'# .t'ft:/L~/1/.t:?R E.A'ffiY5/P# TYPE.I,t~R IEuNE/1/T ... "')_· .:'-+'RR~t»E ft:/PP.t'Rr P/7/ / ..-p-- b.l#t?# .Ct1.e""'.R.t7P..T I/1R----/ -F/AALZVf#//'.T .t.EP'ER 1.-eK.I"El S..P.A~//1/t» R###Et? R.t:?.L.tER .RE/1R I?Eir TY.PE4'1 Ci«R/11/JE /~~V~T.R,u?ar? end o£ the return stroke o£ the printing bail, the escapement pawl operating arm lifts the £ront escapement pawl out of engagement with• the escapement ratchet and at the same time the rear pawl moves against the ratchet. This will allow the spacing gear to revolve far enough to complete the remaining portion o£ the space at the end ofwhich time the rear escapement pawl will enga&e a tooth on the ratchet. as a warning to the operator that the end o. the line is near (Fig. 11 & Illus. 8). The margin bell pawl on the typebar carriage will depress the margin bell cam, tipping it, moving the bell hammer away from the bell against the tension of its spring. When the typebar carriage bell pawl has been spaced beyond th€ cam, the bell hammer will be released and its spring will pull the hammer against the bell • Margin Signal Bell .Ribbon Feeding Before the typebar carriage reaches the end of its travel, ~t operates the margin bell The end of the ribbon feed lever engages with the notched extension on the pullbar bail ~ /"EEPLD'ER----.. ,e$.gCW rEEt? MHZ---- -" ,,c) 'lL IAR .UZ PLIMFA' ''-Y6. "':;;:'~ ____--R$$tW ;:"EEP RACKET 6£.4(1 ~ R/41tJIY rEB' R-4TC#ET- -'--, R/BitJ# /"EO f//1"1/"T uEM- ~YE.RT~KrHtW ffEP SIIVT R/8ilt1# FEEtJ f//.A/7 (.FEE /LLt/5TR/97/PN 6) Fig. 12 Page 12 iJ SECTION P70.0l3 M,..fR#$ SfiL ~Jn. - - - - . . ~~/Al;;ERE/?/RA/.:f"HH.QAit'N .f,P,..fC'/A/6" R-#a-_ _ _ _ _, 5?-#'-'AVu v~R-------, (' NARHA/ SELL. C#/¥ .:?#'#_,.,::-;: N-#Rv/NS~LCAN ______~ .RuA/A: 1.1u B.lf/L Nt?~W?7#u .F##,.:::-r. NAA'v/AV BBL #.-9'NIYER----...._ ( ~AFv/AVSCC££ ______________ $"?A'C$v 1..-71? LEI/ER _ _ _.-- ---.:>rH~>//VV Ef$,PENE#/R/?~#E/ Nda' 5/rA,.:::-r .tFE-'?R ~ NA'/;1/ SIIA'_,.,::-r • 5;tf'.-9C'//I/u In:'/' 5LEEI/E 1/ER?/CAL 5;tf'.-9C/4/v 5#A'r?: f#-'?.rT vE-'?R ~R/AuE RE/?'R/Y .?;t?ERA'l7N'd LFI/E.f' L/A/K' REAR WEft/ TY.P/Alt¥ t/N'/T /LI.t/5TR/77lt7# d plunger (Fig. 12). The ribbon feed pawl, which actuates the feed ratchet, is attached to the ribbon feed lever. With each operation of the pullbar bail plunger the ribbon feed ratchet and the ribbon feed ratchet gear, which is attached tb a common 'shaft, is advanced one tooth. This motion is carried through a train of gears and shafts, causing one of the ribbon spools to be revolved. Ribbon Reverse ( Assuming that the ribbon is being wound on the right-hand spool and is almost unwound from the left-hand spool, an eyelet which is fastened to the ribbon will engage and move the left-hand ribbon reverse arm. This arm moves the left-hand ribbon reverse pawl into R$.6't'# REf/ER5E ~#Ar,.T: the L a.th of the ribbon reverse bail (Fig. 13). As the bail moves toward the rear it engages the pawl, moving the ribbon feed shaft to the left. This will disengage the right-hand ribbon feed shaft gears and engage the left-hand gears. The ribbon will then be wound on the left-hand spool. The reversing operation takes place in a similar manner on the right side of the assembly when the eyelet near the right end of the ribbon engages with the righthand ribbon reverse arm. Ribbon Oscillation So as not to obscure the printing, the ribbon is moved below the printing line after each character has been printed. This is accomplished by the ribbon oscillator which is ~-----R/.6'.6't?/Y REf/ERfE#RN $Ef/EL DEAR'----~ ( --R$BP# .rEEIJ g_.,_rr f/ER77CAL R/Ha+' fffiJ 5#;1/n- Rd9.6't'# REi"ER.JF PI'IJYL--- -R/4'&::1+' REYERfE IJI/L (5EE /LLU5TRA'?7t?N 6) Fig. 13 Page 13 SECTION P70.0l3 actuated by the movement of the pullbar bail plunger (Fig. Normally the ribbon is held below the printing line by the pullbar bail plunger when in its rear position. The forward movement of the pullbar bail plunger will permit the oscillator spiral spring to move the ribbon shield upward carrying the ribbon into the path of the typebars. l4). The height to which the ribbon oscillator will raise the ribbon is determined by the position of the shift lever roller. Both the oscillator and the extension are pivoted on the ribbon shift lever. The shift lever spring holds the shift lever roller against the slide bar, which is mounted on the platen assembly (Illus. 9). When ~he platen shifts to the "Figures" position the shift lever roller moves up with the slide bar and allows the shift lever spring to pull the ribbon oscillator assembly and ribbon to the higher printing line. Ribbon Lockout The ribbon lockout bar is provided for the purpose of locking the ribbon below the printing line when stencils are being made (Illus. 7). When the ribbon lockout bar is moved inward manually, it .engages the oscillator extension, holding the oscillator assembly in the lower position, with the ribbon below the printing line. Functions The operations of functions is accomplished through the medium of function levers. When the printing bail is in its rear or normal position, the function lever bail, which is attached to the printing bail, holds the function levers away from the vanes. As the printing bail moves forward, the function lever bail roller will move down off the high portions of the function lever rear arms, permitting the function lever springs to pull their respective levers against the vanes. The forward arms of the function levers are notched so that when a function combination is set up on the vanes the selected function lever will move forward farther than the other function levers (Fig. 15). '~ ') When in the selected position, the carriage return, line feed, figures, letters, bell and motor stop function levers will be in the path of one of the blocking extensions on the function lever bail (Fig. 15). This will prevent the printing bail from moving forward ) I""UNCTION BAIL. ··~ .,J "<eSeT LEVeR l.OWERAOo.IUST!NG SC!ii!eW BLANK FTINCTION l.EVEIC £.¥TENSION '-.liNIVEICSAL FUNCTION I..EVEta EXTENSION T•LEIIE!e '----JNTE~MEIJIAT£ 1..£V£.e .;C""RONT V/EW- Tf'P#V6 VN/T /L.LV5TRATA::/# 9 Page 14 FUNCTION LEVER fiJAfL SECTION P70.01.3 bail blade returning to its forward position in readiness for the next function. far enough to a!!OW the typebar carriage to space. However, when the locking, universal, space or blank function lever is selected, the function lever bail will not be blocked inasmuch as their operation depends upon a complete movement of the printing bail. ( ( Carriage Return When the carriage return function lever (second from the right) moves into engagement with the vanes, the function lever extension moves the carriage return latch bar upward out of engagement with its latch. This releases the carriage return operating lever, which actuated by its spring moves the carriage return clutch fork upward, disengaging the upper carriage return clutch member from the lower roAmbar. The spacing shaft is then free to turn in its sleeve so that the typebar carriage may be pulled back to its extreme left-hand position by the carriage return spring (within the carriage return drum) through the medium of the draw strap (Illus. 9). The notch on the reset bar will then be engaged by the function bail and moved to the rear. As the reset bar The function bail, mounted on the bail mounting shaft, is used to operate some of the functions and is actuated by the function bail cam (Fig. 15). The function bail spring holds the function bail cam roller against the cam at all times. After the printing bail and the function lever bail move forward sufficiently far to release the function levers, the function bail roller starts to ride up the high part of its cam. This moves the function bail blade toward the rear, engaging and operating any function pushbar that may have been moved in its path by a selected function lever. The function bail roller will then ride down to the low portion of the function bail cam, the RBb't:HI .5/f'/ELJJ _,h'F?" LD'ER Rt'LL.t-A ~ m ~ R/6'b't'#5#//"7" LEI/ER SLIIAfMR -R/b'b't'# t'.5C/LL.47"t:7R ~ 5#//"7" LD'ER f.t'R.M ~~----E%TEAIS~AI R/.B#t:?# f#//"7" LEJIER 8RA&£'ETtl I ....... .!. ~OZ'ttLPER SCREW-----' • PI/LL BAR BAIL Rt/Ait5"ER- ~ -LE,.CT PLti/1/&"ER ARN -PLtiA/IFER ,fi:/LLER (5EE /~~ U5TRA'T/t?# ~ Fig. I'R//YT//YIF ##/L BL/I.PE5 ( --== 14 ~/"ti#C/47# LEYER 8/1/L A -fl fl /_./ rt/#C/lt7# Lfl'ER s,..;IL Rt7LLER ~+ ??; 4}; I"" B~ot7/W EJ'ff!V510N- .,~ YAAIE.5 rti!W'T...e'.¥ .9/1/L .f,.t:/('//1/v------._~ FVAIC/lt?AI M/L CAN--- rtiAICJi'.tW B/1~- ( /1/i/RE Sll/1"/ ~ BlfR-Ft/AIC?7d# B/1/L BL/I,tJE ~~-rt/IYC/lt1AI LEI/ER fPR!lYt5" - - ----, :;> z" 7 U' ; ~RE StW'TI"P'!VC770;V LEJ/ER S , ; if'dma;/tl>));J ,..::VA/Cl7t:7AI LFf/ER E.-YTEA!f/t7A/ (S"£E /LLt/5TRt4T/t?N 9) Fi:::;. 15 Page 15 SECTION P70.0l.3 and the carriage return latch bar are both pivoted on the same screw the latch bar will be reset into engagement with its la~oh (Fig. 16). In the meantime the function lever bail will have been returned to its upper position and the carriage return function lever extension will have been moved down below the carriage return latch bar. During the time that the carriage return operating lever was being operated by its spring, the look bar was moved through a series of levers until its notch engaged with the lock bar latch (Fig. 16). This held the carriage return cl~tch members disengaged so as to insure a complete return of the carriage. One end of the dashpot lever is attached to the dashpot plunger and the other end projects into the path of the typebar carriage. Just before the typebar carriage has returned to the beginning of the line, the left-hand margin adjusting screw (attached to the carriage) strikes the end of the dashpot lever driving the plunger into the dash~ot air chamber absorbing the shock (Illus. 2). When the typebar carriage returns to the beginning of the line, the dashpot lever stri~es against the lower end of the lock bar latch, releasing the lock bar and carriage return clutch fork which in turn permits the carriage return clutches to engage. The carriage return lock bar extends beyond its latch s·o that it may be operated manually. Figure Shift and Letter Shift The figure shift function lever, third from the right, when selected will move the figure shift push bar uptobring its notch into the path of the function bail (Fig. 15)• This push bar when moved by the function bail will turn the right end of the shift link, to which it is connected, toward the rear of the printer and the left end of the link toward the front of the printer (Fig. 17 & Illus. 8). The shift lever which is engaged in the left end of the link is thus moved so as to pull the rear end of· the platen assembly downward through the medium o~ the shift vertical link. The platen roll will be brought to its upper or shifted position. The letters push bar is connected to the left-hand side of the shift link. When the letters push bar is operated by the function bail the action on the platen assembly will be reversed, bringing the platen down to the letters position. y~ ') The shift detent is provided to hold the platen assembly firmly in either the shifted or letters position. Sixth Vane The lower end of the spring attached to. the sixth vane fits into the notch in the forward end of the letters push bar (Fig. 22). When the platen is in the .figures position, ~F#~.T~~FR-----------------------------=~~ l~~B~R~TC#---- ------------------_~J l~CK BAR ---- ~ tiiRRIAII'E A'El"t/R# &IA!="R...9Ji'IVII' LffER .J"J'R/#11' ,----l,..-t---------~,..PRRIAIIE RE7't1RIV a<'ER..+'/7#11' LEJI'ER :--- OA'"Rh'l7~LEJ£R SCREW .£~==:;L_ ... 5P..+'O#tl fii/V'7' lmw ____. ..--------~19RR/AII'~ RETVR# tzt/.TC/1 ,&"~RK - ,) C.«R/...9tfERE.TPR# IZV'.TC# >'W..+'CTI~N' B-+'li ~19RR#911'E RETVAW \f:"ti!VCT!tW LEf'ER E.r/EN'f/tJ# U'R#911'E REWRN' LATCH' B#R CI?RR/Ift:E RETI/RN RESET 8t'?R '-----CARRP?II'E REJZIR# tATC# B.IPR L4/Cit' (5EE /LLt/STR.4J7t',Y 8) Fig. 16 Page 16 \(~ SECTION P70.013 ( ( the letters push bar is in its forward position and the rear edge of the sixth vane is moved down. When the platen is in the letters position the. rear edge of the sixth vane will be in its upper position. When the letter "S" or "W' is selected and the platen is in the letters position the bell and motor stop function levers will be inoperative because the sixth vane prevents their selection. With the platen in the figures position the sixth vane will not prevent the selection of the bell or motor stop function (See "Motor Stop Function" and "Signal Bell Function"). Note: Printers not equipped with mechanical motor control have period on the upper case of "M" and the motor stop function lever is omitted. Some printers are arranged to ring the signal bell on the upper case 11 J 11 or on the "Blank" in which cases the bell function levers are designed to be selected on these combinations. The sixth vane however is not used in connection with the signal bell function when the bell is made to ring on the "Blank" combination, as the platen may be in either the "Figures" or "Letters'' position. Spacing Function Spacing other than that accompanied by printing (such as spacing between words, etc.) is accomplished in the same manner as that described under "Spacing" except that there is no pullbar to be selected, Unshift on Space Function If desired the printer may be arranged to shift the platen to the letters position on both the space and letters combinations. This is accomplished by means of the space function lever. When the unshift on space feature is no