Manual / Guide · 1943
Bulletin No 172 - Description Typing Reperforator Bulletin 172 1943
Bulletin No. 172 — Description, Typing Reperforator (Model 14)
Manual / Guide · 1943
Bulletin No. 172 — Description, Typing Reperforator (Model 14)
BULLETIN NO. 172 ISSUE % OCTOBER, 1943 • • TELETYPE PRINTING TELEGRAPH SYSTEMS DESCRIPTION TYPING REPERFORATOR (MODEL 14) CTEL~IYPEJ CORPORATION sv• ••••••., ~,. Westem Elecrrlc Company CliiCA<;O. U.S. A. '""titd It~ U. S, A. - .. SENDING-RECEIVING TYPING REPERFORATOR WITH COVER • RECE VING-ONLY TYPING REPERFORATOR (HIGH BASE) COMPL£ TE WITH GO\/ER DESCRIPTION OF MODEL 14 TYPING REPERFORATOR CON.TIJITS • • ... SIGNAL CODE • • • • • GENERAL • ... ..... ... Page .. . . ... 1 . ... .. ... • • DESCRIPTION OF RECEIVDIG UNIT OPERATIC!! . . . . . . . . . . . . . . . DESCRIPTION OF TRANS14I'!'TOO UNIT OPERATION Clutch Throwout Lever • • • • • • Code Bar Locking Lever • • llain Sha.rt Assembly • • • Mechanical Tape-Out Alann OVerlap • • Printing , RibbQn Feeding • • • • Ribbon Reverse • Sel ecting Mechanism A. Pulling llagnet Selector • B. Holding llagnet Selector • S1gnal Bell Spacing Tape Perforation {)pper and !.<Mer Case Shift Yec))anie111 • • • • • • • .. • .... .. .... ORIBN'I'ATION .. .. . . .... . . . . . DESCRIPTION OF OPTIONAL F'l!lATURES .. Backepace llechaniiSIII .. • • Clutch Throwout Lever Contact Mechanism Keyboard Lockout , , • .. Line and Selector Circuit Closing Jack • 2 4 5 6 4 9 7 6 7 8 • 4 • • • ... IIOTOR SPEED CONTROL 2 4 5 8 7 6 8 ... . .. 9 SYNCHRONISM llagnet Operated Tape Feed-Out Lever Mechanical End-of-Line Indicator Mechanism Polar-Neutral Key • • Radio Frequency Induction Suppressors S1gna1 Line Re l.a.Y • • • • • Suppression of Printing on LcrKer Case "Blank" Selection Tape Feed-Out Control Yechanisn , Unshift on Space • , • 9 ... .. 10 10 l3 12 l3 l3 lO l2 14 13 • • • l3 14 11 14 GENSRA.L The llodel 14 Typing Reperforator is a motor driven mechanl sm for receiving messages over wires and recording the messages in both code perforations and t:rp811'rit ten characters on the same tape. When used with a keyboard transmitter in a local circuit, it also serves the purpose of a keyboard tape perforator. Receiving units of this kind are particularly adaptable for uae at message distribution centers because the perforated tape may be used to retransmit the menage to one or moro atations by means of another unit known as a transmitte~diatributor, thus eliminating the necessity for manual transmission by direct keyboard or manual preparation of perforated tape. 'nla tJ'pewdtten characters on the tape facilitate identification and distribo.tion of the message tape at the message canter • • A caDplete set conaiate of a t:yping Nperforator unit, a sending1"8ceiving base, or a receivi.ng-on)Jr (law) base, or a receiving-only (high) base, and a cover. A c0111plete sending-nceivi ng set, without cover, is shown in Figure 1, a complete receiving-only (low) set, without cover, ia shown in Figure 2, and a COIIIPlete receiving-only (high) set, rlthout cover, is shown in Figure 3. The t:yping reperforator unite used at receiving-only stations are basically the sam& as those used at sending-receivi ng stations. A typical t:yping reperforator unit equipped rlth a pulllng magnet selector ia abawn in Figure 4. A typical typing reperforator unit equipped with a holding JIBgnet selector is shown in Figure 5. Theae typing reperforator units consist, essentiall,y, of a motor, a main shaft assemb]¥, a selector mechanilD, mechaniSIU for typing and perforating, a tape teed mechanism, and a ribbon feed mBChani!lll. S•nding-reoeivi ng e~tiono omploy a baoo which includoo a keyboard transmitter as shown in Figure 6. It consists, essential]¥, of a tape conta.i.J1... ar, tap&-out mechanism, terminal blocks, slip connections, a motor switch, and a transmitting unit . This unit originates electrical ilnpulsee of the five-unit signal CQde for the operation of receiving \U\its at aiiJ" .station to which the signals are transmitted. These signals cause the receiving unit to record the message senT. by the keyboard operator. The signals ~ also be used to operate on]Jr the local t:yping reperforator, preparing perforated tape for use in a tranamittel'-di stri butor. This base is also arranged to accOJDUodate certain optional features such as a control relay or a mechanical end-of- line indicator, both of which will be described lnter along with othor optional featuroa . • • A typical (low) base for a receiving-on)Jr station is ahown in Figure 7. It consists of the same essential parts as are provided on the sending-Nceivi ng base, except that it does not have a transroitting unit, This base is also arranged to accocmodate certain optional features such a.a a signal line relay base or a control rela,y, botb of which will be described later along With other optional features. A typical (high) base for a receiving-onl,y station is shown in Figure 8. It consists, essentially, of a trame, a tape reel, terminal blocks , slip connections, and a motor switch. It ia also arranged to accommodate certain optional features such as a signal line relay or tape feed-out mechanism, both of which will be described later along with other optional features. rlde. The t:yping reperforator utilizes standard perforator tape 11/16" A method of tape perforating known as chadless perforating is employed - 2 - (B-172) to permit perforation of t he tape in the same space that is occupied by the typewritten characters. The punchings, or chads , are not completely severed from the tape but remain attached to it at t he ir leading edges so as to form lids over the hol es. The legibility of the typewritten character is not impared by this type of perforating because the perforating does not eliminate any portion of the tape. Typing and perforating occur simultaneously, but due to the fact that the platen is to the right of the perforator die block, characters are typed at the right of their respecti ve perforations. The separation bet ween the typewritten character and its associated perforation is s ix character spaces. This separation must be taken into account when tearing message tapes from the unit or in cutting the tape. \Then the tape is to be used for transnission by means of a transmitter distributor, the end of the tape should include all of the typewritten characters in the message, and the first typewritten character of the message must be preceded by at least six sets of code perforations in order to transmit the entire message. When a message tape is inserted in the tape guide of a transmitterdistributor, i f tile typewritten symbol of the character to be transmitted is positioned opposite the tape-lpcating mark impressed in the tape guide, the code perforation for that character rlll be over the tape sensing pins, in positio~ for transmission. Under this condition, if the tape retainer of the transmitter distributor is fastened over the t ape, the tape locating mark 11ill be covered, but the typewritten character will be visible immediately to the right of the tape retainer. SIGNAL CODE The signal code used to operate the typing reperforator is known as the five unit code. It consists of :32 arrangements of current and no-current intervals of code combinations, each consisting of five parts. To print a certain character the code combination assigned ~ that character must bs received. These combinations are shown in Figure 9. Each g~:"oup of five sel ecting intervals is preceded by a "start" interval and follO!fed by a "stop" interval. The "start" and 11 stop" intervals are used to maintain synchronism between t he transmitting and receiVing apparatus. DESCRIPI'ION OF TRANSl!ITTING UNIT OPERATION The keyboard-base (Figure 6) consists of a set of keys, key levers, a bank of transmitting contact springs, operating cams, clutch, and driving gear. This driving gear is connected through the intermediate gears to the main shaft on the rece i ving unit vthich in tum is driven by the motor. The transmitting cams are normally held stationary because the clutch members on the driving shaft are held apart by the elutch throwout lever (Figure 1.0). When a key i s depressed the driven clutch member is permitted to move into mesh with the driving clutch ~ber causing the cam s l eeve to revolve. At the end of each revolution the driven clutch member is disengaged by the clutch throwout lever bringing the cams to a st op until the next key is depressed. Beneath the key levers are five selector bars and a universal bar extending across the width of the keyboard. The sel ector bars are proVided with saw tooth shaped notches, as shown in Figure 11, according to the requirements of the signaling code. These bars rest on rollers and are guided at each • • - 3- (B-172) end so that they my be easil¥ moved endwise. When a key is depressed the key lever 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, controls the starting of the transmitting cams. It is pivoted at both ends in such a manner that the depression 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 permitting the transmitting cams to start rotating (Figure 1.0) • • Each selector bar engages a vertical locking lever at its right h.wi extremity and positions it to correspond with the signal impullse to be t-ransmitted (Figure 11). Each locking lever controls the motion of a contact lever either by allooing the contact lever to close its contact when the cama revolve or by 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 , the locking lever engages the contact lever and prevents it from rising into the indent of the cam as the cam rotates, thus holding the circuit open for that impulse (Figure 11-A). If the upper end of the locking lever is positioned to the right corresponding to a MARKING impulse, it does not intel'fere with the movement of the contact lever (Figure 11-B). Then, as th~ cam revolves, the contact lever rides on the cam periphery and rises into an indent, thereby allowing its contact to close, sending out a !lARKING impulse. As the cams rotate, the impulses, either IJARKING or SPACING, are transmitted in s ucceMion. The start-stop cam (Figure 1.0) controls an additional contact lever which in turn actuates the start-stop contacts. These contacts are opened at the beginning of each revol ution of the cam shaft to transmit the start impulse (spacing) and remain open during the transmiBs:l:on of the five selector impulses. After the fifth 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 key lever is depressed, At the end of each revolution, the driven clutch member is cammed out of mesh with the driving clutch member by the clutch thro'lfout lever. This action prevents the cams from rotating further until the next key is depressed. • The lock loop is used for the purpose of preventing a change in a selection during the revolution of the cams. It locks the selection set up and prevents the depression of another key until the preVious signal has been tranSIIlitted. The lock loop is controlled by a cam on the transmitting cam cylinder (Figure 12) . Keyboards may be equipped with a repeat space mechanill!ll which permits the transmission of continuous spaces (Figure 1.0). When the space key lever is depressed the repeat space rod attached to the space key lever extension will move t he intermediate pawl forward, in tum, holding the clutch throwout lever out of engagement with the projection on the driven clutch member. Thus the transmitting cam cylinder will be pennitted to revolve continuous}3t until the space key lever i s released. - 4- (B-172) D&SCIUPTION OP lmlEIVIlll UNIT OPERATION KAIN SHAFT ASSEMBU' Yotion for the setting up of selections and for the performance o! all f'Unctions ill derived !rom cams mounted on +.he main shaft (Figure 13). This ehatt is driven by a motor through the medium o! a pinion and wo1111 gear . The a'elector cam 11leeve ill fitted over the end of tbe main shaft and is driven through the mediWII of a friction clutch forJilBd by two pair11 of steel diaca aeparated by felt wa11hers. The main bail cam (which provides motion for all other functions o! the receiving unit except selecting, perforating, and spacing) and the punch &1111 cam are assembled in one unit and are driven by a positive clutch consisting o! a driving member and a driven member. A keyboard spiral gear, located near the bottom of tho shaft, is provided on units which are used with a keyboard transnitter. SELECTING MECHANISM The typing reparforator mq be equipped with either of two types of selecting mechanisms - the pulling magnet selector or the holding magnet selector. (A) PULLING llAGtiET S!IBCTOR The selecting mechanism translates the signal line impulses into mechanical motion which causes the code bars to be positioned in accordance with the intelligence impulses received during the selecting cycle. This translation is accompllihed by the selector magnets which actuate the magnet annature 1n conjlUlCtion with the armature spring (Figure 14). !ach selecting cycle ill preceded by a no-current, or "start• impulsa which pennits the selector cam sleeve to start rotating by releasing its stop arm (Figure 15). The armature spring causes the head of t he trip-off eccentric screw to depress the trip latch plunge r actuating the bell crank and trip latch 'llhich tmlatches the stop lever. !ach code bar is positioned by a selector cam through the madiUJ11 of a selector lever, 81ford, and "T" lever (Figure 14). To illustrate, suppose that a aeries of impulses corresponding to the code combination for the letter "E" is to be received: At the beginning of the "start" impulse, the annature moves away from the magnet, releasing the stop ann as explained in the preceding paragraph. The selector cam sleeve starts to revolve, and the No. 1 selector cam engages the No . 1 selector lever <hlring the time that tbe first intelligence impulse of the signal is being received. Since the first intelligence 1mpnlse of the •g• code coai>ination 1.a a current impulse, the magnet &n~~ature is attracted, bringing the right-hand end of the armature extension into the path of the right-hand sword ana. As the No. 1 cam rotates cloekwiae, it rotates the No. l selector lever countereloclofis e causing the No. 1 sword to strike the right-band end of the nrmature extension and to pivot at point •A•. This positions the No. 1 sword so that when the No. 1 Clllll rotates past the tip of the No. 1 selector lever, the selector lever spring will caueo tho sword to depress the left end of the "T" lever, moving the No. 1 code bar to the right. Since the Nos, 2, 3, 4, and 5 intelligence impulses tor the "E" selecting cycle are no-current impulses, the llla8Mt armature moves to C.!::o releaaed position with the lett-hand end of the anzature extension in the r-ath of the left-hand sword arm. Ae the Nos. 2, 3, 4, and 5 • - 5- (8-172 ) cams opel'8te and release their associD.tAd selector levers, the associated code bars either remain in their left-hand position or are moved there b)' the S'lfOrds. With the No. l code bar to the right. and the Nos , 2 , 3, 4, and 5 code bars to the left, there will be a notch in each code bar opposite the "B" pull bar. Refer to Figure 20 tor location of pull bar in relation to code bars . The pullil'lg magnet annatw-e lllttension is locked whUe the position- ing of each sel•'ctor sword is taking place and it is unlocked atter the selector cams pess the peaks of their associated selector levers. This i l aeeomplished by a cam operated locking lner which engages a wedge on the amatw-e extension (Figure 16) • • (B) HOlDING ~Gtm' SELECTOO The holding magnet selector (Figure" 17 and 18) io basically the same as the pulling .mgnet selector. The form~r. however, hu its armature moved against the magnet by a cam, while the latter baa its armature attracted to the selector magnet by magnetism. In the holding magnet selector, the translation of sisnal line i.mpul.ses into mechanical motion is &CCOGPlished by the selector magnet, the armature, the selector arm, the annature cam, and the armature spring (Figure 17). An extension of the armature , which r1dee on the armature cam, moves the armatw-e against the magnet at the time a sign&l line impulse 1a received. The annature will be held against the magnet i t a current (marking) impul.se is received and will be rel8ased i':t'Om the mag,net i t a no-current (spaciAA) impulse is received. The selector arm is actuated by the armature extension becauae the selector arm spring makes a yield connection betwesn these two parts. Therefore, the selector ann instead or the anDature sxtension is used to position the !nfords on holding magnet selectors. The operation of the !nfOrds, "T" levers, and coda bars is the • as that described under "( A) PULLDIG I.!AGN!n' SEIECTOO. • The holding magnet selector locking mechanism ( Figure 19) operates in a manner dmilar to the locking mechani11111 of the pulling magnet selector described above. In the latter, the arms.ture extension mounts the locking wedge while in the Conner the selector arm mounts the locking wedge. Because the armature cam starts to move the e.nnature toward the eeleotor magnet before the locking lever releases the selector ann, the eelector ann spring acts aa a yield between the armature extension and the selector arm. • ., CJ.mCR TRRClf01Jl' WIER During the positioning of the No. 5 selector nord, the sixth CUI of the selector cam sleeve disengage s the clutch stop arm from the driven clutch 111ember (Figure 13) allorlng the main shaft clutch spring to r.10ve the clutch members into engagement cnus1ng the main bail CaJll and punch ann cam to rotate. At tho end of each revolution, the clutch stop ann of the clutch thro110ut lever engages the cam surface of the projection on the driven clutch member, camndng it out of mesh with the driVing clutch meri>er . Thus it may be seen that i.nlmediately after the completion or a selecting cycle the main baU cam and pUnch ana cam will be permitted to rotate one revolution to perform the operations required for printing and perforating, respectively. - 6 - (S-172) PRINl'liD The poorer for the performance of printing and other fW1Ctiona ( emept eelocting, per1'oratil'l8 and spacing) is derived from the main ball which is oparated by the Dillin bail cam tbrough the medium of a bell crank , lever, and plunger (Figure 20). In the normal atop position, the main bail bell crank roller is on the high part of its cam ae ah01m in Figure a:>. In thie position the main bail engages the hookllke projection of the pull bars , pushing them forward awa;r tro.n the code bat'8 eo that the coda bars can ~ positioned by the selector mechani11111, When the lll&in ball cam rotatee, the main ball bell crank r.:»ller ridee down the slope of the main ba.1l. cam, perIUitting the main ball spring to raise the ball. As the main ball movee upward, the pull bar springs IIIOYe the pull bare toward the code bars , The uneelected pull bars are blocked by the coda bars , but the eelected pull bar moves into the path set up by the alignment of notchee in the coda bar e, and a hooklike projection on the rear edge of the selected pull bar is engaged by the main bail, causing the pull bar to be raised, The rack and gear connection between the pull bar and type bar causes the type bar to rotate about its pivot toward the platen. As the pull bar ia moved upward, the eloping surface of the rear projection on the pull bar etriku a stripper plate causing the pull bar to be disengaged fro!ll the main bail short4' before the type bar reaches the platen. llooaentum carries the type bar the retll8.1n1ng di.e tance to the platen. Aa the main bail cam continues ita rotation, it restores the main ball and. pull bars to thair norml stop position. Letter characters are printed near the top of the tape and figure characters are printed near the bottom of the tape. COOE BAR LOCKING LEVER The code bars are locked in position after each selection by the code bar locking lever, located in the extreme right-hand. slot of t he pull bar gy.ide (Figure 21A) . The locking lever is bro~t into engage:DIInt nth •V" shaped notches in the code bars by a spring during tha ear4' part of the upward stroke of the main ball. It is canrmd out of engagement With the notchea by the main ball as the main bail nears the end of its downward stroke. lfhan the code bars are not engaged by the locking lever, they are tree to be positioned by the selector swords and "T" levers (Figure 2lB), TAPE PERFORA'~'IOII Power for perforating tape is deri ved from the punch arm cam on thG main shatt which actuates the punches by means of the punch bail through the mediwa of the punch arm casting, punch bail link, and. punch selector finge.r s (Figure 22). The punch selector fingers are positiolllld by the punch bell crank springs so that the aelection set up in the code bars will be perforated in the tape (Figure 22). The positionil'l8 of the punch e elector fingers takes place ear4' in '..he upward stroke of the main bail, The motion of the code bar locking lover is utilized to operate the code bar bell cranks which move toward the code bars nth the locking lever (Figure 21). It a code bar hall been positioned to the right, the motion of the associated code bar bell crank Will be blocked by t,he code bar as the code bar locking lever movea toward the code bars, and tht. punch selector finger will remain in position to engage the punch as shown in i!~ure 22. It the code bar baa been pooitioned to the lei't, the code bar bell crank will be i'ree to follow the code bar lock- • • - 7- (B-172) ing lever, and the train of linkage between the code bar bell crank and the punch bell crank will be turned in a clockwise direction, thus moving the punch eelector finger to the left so its recees will be under the punch, • Shortly after the punch selector fingers have been positioned, the punch ann cam rotates the punch bail through the mediWII of the punch ar111 caating and the pWlCh ball 1ink. .b the punch bail ca~a rotates, the punchengaging projections of the selector fin&ere, which are in line with tlw punchee, raise the pW>Chu and perforate the tape. A projection on the punch bail engagee the feed punch during every operation. An upstop screw in the punch ball liJnits overtravel o.t' the punches to prevent JIIUtilation or the tape • SPACUC Tape is spaced by the rotation of the feed roll which hu pine on its periphery that engage feed perforation e in the tape (Figure 23). The tape is held in engagement with the feed roll by the tape tension lever. The feed pawl, attached to the punch bail, is held in engagement with the feed roll ratchet by a spring and rotates the feed roll by engaging a tooth of the feed roll ratchet during each downward stroke of the punch ball (Figure 22). The feed roll detent in8Unl& even spacing of the perf oration&. Tape mq be ~paced out of the unit when the signal line is idle by manually operating the tape feed-out lever which 1a mounted on one or the range tinder mounting poste (Figure 4). Operation of this lever allowe the selector c11111 eleeve to rotate freel,y, causing a seriee of •I.ettere1 combination s to be perforated in the tape. OVERLAP In •=izing t he selectine, printing, and perforating operation• described in the foregoing, i t should be noted that the . a electing crele 11 followed iJml&diatel,y by the operating cycle. Near the end of the selecting Call sleeve revolution, t he sixth cam t r ips the clutch throwout lever, allCMing the main ball cam and punch arm cam to make Ollil revolution. Thus it mq be seen that the printing of a character or the operation of a .fUnction requiree tillle equivalent to both a eelecting and an operating cycle. However, the selection of the next character tJJJJ:Y be made at the same time that the perfol'lltance of the previous operation is taking place. This arrangement is known aa overlap and is uaed to facilitate printer operation at high epeeds. Without this feature , it •ould be necessary to allow ti.llle for operation a..tt.er each selection. RIBBON FEmiNG l The ribbon feed lever is operated by an 1Ildent in the main !:ail plunger. Attached to the upper end of the ribbon feed lever is the ribbon feed pawl which engagee with the teeth on the ribbon feed ratchet. With each operation of t he main bail, the ratchet is rotated a alight amount. Thi.e motion is carried through either one of two bevel gears on the ribbon spool shafts, causing one of the ribbon spools to be revolved ( Figure 24). -8(B-172) RIBBON HEVERSE Assuming that the ribbon is being wound on t he l eft-hand spool and is almost unwound from the right-hand spool, an eyelet which is fastened to the ribbon will engage and move the rightr-hand ribbon reverse arm. This ann moves the right-hand ribbon reverse paw1 into the path of the ribbon reverse bail tFigure 25), As the bail moves downward it engages the r ibbon reverse pawl moving the ribbon feed shaft to the right tFig ure 26). This will disengage the lett-hand ribbon feed bevel gears and engage the right-band bevel gears. The ribbon rill then be wound on the right-hand spool. 'l'he reversing operation takes place in a similar manner on the leftr-hand side of the assembly when the eyelet near the left end of the ribbon engages •dth the left-hand ribbon reverse arm. UPPER AIID WlfER CASE SHIFT MECHANISM The platen consi sts of a disc of synthetic rubber about 1/411 in diameter mounted on a cylindrical steel rod of the same diameter about 1/2" long. This assembly fits into a well in the platen block which is mounted so that it can be shifted back and forth on the platen shaft beneath the tape (Figure 27). To print figures when the platen is in the LEI'Tm5 position, the figures" pull b&r is selected. As the main bail moves upward, it raises the "figures" pull bar, and a horizontal projection at its lower extremity unlatches the shift lever from the shift bell crank on t he platen shaft allowing the platen shift spring to ~rove the platen block to tho FIGIJU1S (forward) position. In this position, the platen will support the tape opposite the figures on the type pallets. 11 When the "letters" pull bar is raised by the main bail, an extension on the pull bar engages the left-hand arm of the shift rocker lever moving the rear extension of the shift rocker ann downward. The shift rocker rotates about its pivot and the upper notched end is moved toward the rear, moving the platen block with it, through the medium of the shift bell crank and the platen shaft. The shift lever latches the shift bell crank when the platen reaches the LETTERS position. SIGNA L BELL Some units are arranged to sound a signal bell when upper case "S" is selected. 1fith the platen in the FIGliiES (forward) position, the lockout lever arm of the shift mechanism holds the pull bar lockout lever in such a position as to allOI'f the selection of the "Bell" pull bar but to prevent selection of the "S" pull bar (Figure 28-A) . With the "Bell pull bar selected, the main bail engages the notch in the "Bell" pull bar and lifts it upward. A projection near the bottom of the "Bell" pull bar engages the eccentric screw of the bell hammer, causing the hammer t o strike the gong (Figure 28-B). With the platen in the LE'l'TERS position, the pull bar lockout lever is positioned so that the "S" pull bar may be selected and the "Bell" pull bar is blocked (Figure 28-C) • - 9- (B-172) J&:HAIIICAL TAPE-0111' AIARII Keyboard bases and receiving-onl,y (low) bases are provided with a bell mechani91!1 'lfhich eounds a warning sienal when the supply of tape is nearly exhausted. This mechanillm consists of a bell, a bell hammer operated b)' a post on the keyboard gear, a bell hammer latch, and a tape-out lever. IIOl'OR SPEED CONl'ROL • In order to maintain the motors at the tran91!1ittin g and receiving stations at the proper speeds, the apparat us is equipped with either constant speed motors (synchronou s - will operate onl,y on regulated AC current) or with governed speed motors (will operate on AC or DC cWTent) . \then a governed speed motor is used tbe governor is attached to one end of the motor shaf t. This governor and a resistor control the speed of the motor . The motor governor (Figure 29) is used to shunt the resistor in and out of the motor circuit. This is done b)' means of the governor contact arm. The contact ann sprine (Figure 29) holds this contact arm a~ainst the stationary contact until the centrifugal force of the contact arm (as the motor and governor rotate) overcomes the tension of the contact arm spring. 'lrhen the contacts open, the reaistor is shunted into the motor circuit, reducing the speed of the motor. \'lhen the contacts close, the resistance is shunted out of the motor circuit, increasing the speed of the cotor. The rapid operation ot these contacts tends to hold the notor at a very nearly constant speed. The tension of the spring datermines the spoed at llbich the motor will operate, since i t holds t he eont.act of the contact arm ngc.inet ito otntionary ccmpanion contact, Therefore, the speed mey be adjusted by turning the speed adjusting whee l (which extends througj\ the cover of the governor) in a diraction to increase or decrease the tension of t he spring. The governor is equipped With a target consisting ot alternate black end white spots. A speed indicator (tuning fork with shutters attached to the ends of the tines ) is used to Vi sua~ check the motor speed. With a properly adjusted spring tension, the spots on the target appear to be stationary, when observed through the shutters of the vibrating tuning fork. No speed setting is required on printers equipped with synchronous motors since they are constant speed motors. STr.CHRONIS 1.! • In order that the signals sent out by the transadtter ma.Y be ioterpreted correct~ by the r eceiVing units, it is necessary to keep the receiving units in synchronism with the tran91!1itted signals. Synchroniam ia maintained by having the receiving selector cnm sleeve rotate taster than the transmittin g cam cylinder and by use ot the "start" and • stop" impulses in the following IMlUler: = The reception or t he start impulse starts the s elector sleeve on the receiving unit revolving. At that moment, the selector cam. sleeve i s in unison with the transmittin g ean1 cylinder. The selector cam sleeve is so constructed that the distance traveled frOI!l the position where the cam sleeve starts t o move a :!!elector lever to the position where i t starts to move the next selector lever is greater than the distance traveled b7 the transadttin g cam cylinder, from where it can control t he t ransmission of one impulse to -10(B-172) where it can control the transmission of the next impulse. In other words, for a certain travel of the tranamitting cam cylinder, the corresponding travel for the selector cam sleeve is greater, but as tho selector cam sleeve travels faster, it 'Ifill reach its second position at the same ti.ale tho transmitting cam cylinder reaches its second position, The selector cam sleeve completes its revolution before the tranllmitting cam cylinder, but tho trarumitting cam cylinder sends out tho stop impulse which stops the selector cam sleeve until the transnitting cam cylinder again sends out the start i.alpulao. Usually the selector cam sleeve is one-seventh faster than the transmitting cam cylinder, and the selector cam sleeve is at rest one-seventh of the transmission time. If the speed of the selector cam sleeve is faster or slOII'er than the proper speed, the cam remains at rest more or leas, as the case may be. Of course, there ~ be a slight error in the relative position of the selector cam sleeve in the various positions, but the mechanism is so constructed as to compensate for this and, due to the fact that the selector cam sleeve starts each revolution in unison with the transmitting cam cylinder, this error dQ&s not become accumulative. ORlENTATION In order to utilize the receiving margin of the selector mechanism to the best advantage, it is necessary to plac.e the starting point of the selector cam sleeve in the most favorable position. This is accomplished by means of the range finding mechanism. llow>ted on the stop lever plo.t.e of the range findf.ne llli>Chanism a.-.. the atop lever and the trip latch 1fhich can be moved, thereby varying the relation between the start of the selector cam sleeve and the time the selector cams operate the selector levers (Figures l4 and 17). A. graduated seale indicates the setting of the stop mechanism, and a thumb screw holds it in place after it has been set. The range is detonnined while receiving "m'" on the receiving unit, by moving the range finder index am in one direction until errors appear and then moving it back slowly until the errors disappear, noting the position on the scale. In a similar manner, the other limit of the range is located by moving the indo:x arm toward the opposite end of the scale. The proper setting is mic:hm;v between these two limits. OESCRIPriON OF OPriONAL FEATtmS There are numerous optional features which are applicable to typing reperforator sets. All of these features cannot be incorporated in a given set at the same tims, however, nor are they all applicable t.o aey one set individually. The features which are at present. available will be described immediately following. IIA.GNET OPERATED TAPE FEED-OOT LEVER Remote control of the tape feed-out features is provided for by the magnet operated tape feed-out lever, It releases the selector cam sleeve so that the sleeve rotates freely, causing a series of "Letters" co!llbinations to be perforated in the tape . The lever is operated by a magnet which is mounted on the rear of the selector mechanism mounting plate. The magnet is energized • -11 (B-172) through a local circuit. TAPE FEED-Our CONTROL h!SCHANISII: • In order to transmit the end of the last message perforated, the tape must bo spaced out of the machine, If the tape 1_, to be sent through a transmitter-distributor adjacent to the t;yping reperforator without severing the tape, it must be spaced far enough to penoit the last perforations of the message to be transmitted. If the tape is to be sent through a tranamitte~ distributor some distance from the t;yping reperforator, it i5 only necessary to space the tape so that the end of the printed message clears the tea~ff edge of the left-hand tape guide. Jhen this condition is f'ultUlad, the tape may be tom off, Tape is spaced out by unlatching the selector cam sleeve to allow it to rotate t'ree]Jr. This operation is initiated mamal]Jr by maaentari]Jr depressing a push button on the t;yping reperforator. This e auses a magnet to unlatch the selactor cam sleeve and puts into operation a timedelay contact operating mechanis:n which automatical]Jr stops tape feeding after sufficient tape has been spaced out. The circuit is so arranged that this operation can also be initiated from a remote control push button. The tl.Jne delay feature is adjustable over a limited range to provide for feeding out tape to meet either of the requirements previoWI]Jr mentioned. The operation of the mechanism is e:xplained :i.mmediate]Jr following: Referring to the schematic circuit in Figure JO, it Will be seen that lfhen either push button is depressed, it opens the circuit to the worm follower disengaging magnet mounted on the tape feed-out mechanism bracket in bAr.k of the right.-hanrl ribbon spool cup. When t.he m.a.gnet. arn>At.U%'a is releaeed it opens its own locking circuit and closes two pairs of contacts (Figure 31). One of these pairs of contacts prepares a circuit to the selector cam trip magnet on the selector mounting plate. This circuit is complet.ed and the selector cam trip magnet is energized when the push button is released. The othsr pair of contacts prepares a circuit to the worm follower contacts, the function of which will be described later. Operation of the trip magnet unlatches the selector cam sleeve, allOifing the main shaft to rotate and causing the unit to feed tape. Since the selector armature remains in the marking position during the rotation of the selector cam. sleeve, the "letters• combination is perforated in the tape. The selector cam trip magnet does not become energized until the circuit through the push button is restored by releasing the push button; therefore, if the tape feed-out push button is held depressed, the feed-out operation 11ill not start • • • In addition to opening its own locking circuit and closing t wo othsr circuits, release of the worm follower disengaging magnet armature allows the worm foll011'er to become engaged with the teeth of a ratchet driven worm gear • This gear is rotated by a pawl mounted on a lever which is operated by the main ball cam. As the worm rotates it advances the worm follower toward a pair of contacts. When these contacts close, they complete a circuit to the worm follower disengaging ma.gnst which circuit was prepared b,y the closing of contacts referred to in a preceding paragraph. When the magnet armature is attracted, the magnet locking circuit is restored, the worm follower is disengaged from the worm and the circuit to the selector csm trip magnet is opened, releasing the trip magnet anoature, thereby stopping the rotation of the selector cam sleeve, -12(B-172) Provision is made to interrupt tape feeding imnediately upon reception of line signals . To accomplish this, the tape feed-out circuit ill arranged eo that the worm follower disengaging magnet will be energized when the tongue of the line relay to uches the No. 5 (spacing) contact. Operation of this magnet will restore the tape feed-out mechaniam to its unoperated position, as eXplained in the preceding paragraph. 'Rhen it ia desired to prevent operation of the typing reperforator without disconnecti ng it !rom the signal line, a tape-arrest ing circuit may be closed ~ means of a key at a remote location. This key causes battelf to be applied to the selector magnets, thus preventing recepti on of messages. In additi on, the tape-arrest ing key cauaea the tape feed-out mechanism relay to operate ( Figure 4) which disconnects t he tape f eed-out circuit !rom the line relay, thus permitting the tape feed-out mechanisn to be put in operation without being subject to stoppage ~ line signals. • Jm:HANICAL END-OF- LINE IIIDICATOR l'ECHAIIISI.! When a typing reperforator is used with a keyboard transmitter for transmittin g on a circuit which includes page printers, the mechanical end-ofline indicator machanilllll informs the keyboard operator when t o send the "carriage return• and " line feed" signals to avoid overrunning the lines being typed~ page printers. The approach of tbe end of a line is in:Ucated by the li€Pting of a signal lamp which is mounted on the keyboard base. The mechanica l end-of-line i ndicator mechanism replaces the standard right-hand ribbon spool br acket assembly. In addition to the parts furni ~h~A wit h the standard ribbon spool bracket assembly, the end-or- line indicator mechanism i ncludes, essentially , a wonu and ratchet, a cam follower lever and pawl, a wom fol.lolfer pivoted on a movable ball, a special carriage return pull bar, a contact assembly, and a oi8nal lamp assembly. AU of tbeee parts mo\mt on the typing repertorato r unit with the exception ot the signal lamp which mounts on the keyboard base. The worm ia o