US2228417A - Code converter - Google Patents

Description

J. A. SPENCER CODE CONVERTER Jan. 14, 1941.

Filed Aug. 26, 1939 6 Sheets-Sheet 1 A INVENTOR. my. JPM/@fp ATTORNEY.

Jan. 14, 1941. J. A. SPENCER CODE CONVERTER Y Filed Aug. 26, 1939 6 Sheets-Sheet 2 INVENTOR,

./Ms A. SP5/cre BY 7% s ATTORNEY.

Jan* 14, 1941- J. A. SPENCER 2,228,417

CODE CONVERTER Filed Aug. 26, 1959 6 Sheets-Sheet 3 INVENTOR. 4 JAME/Q. SPENCER ATTORNEY* Jan.

14, 1941. J. A. SPENCER CODE CONVERTER Filed Aug. 26, 1959 6 Sheets-Sheet 4 or Q asf IO O

hFIC5-4 IVENTOR.

JPEA/cfk /w-Q'W ATTORNEY.

Jan. 14, J, A. SPENCER 2,228,417

CODE CONVERTER Filed Aug. 26, 1939 6 Sheets-Sheet 5 m #by H1 ,SLO Ilooollo ol G 000000000 ojo o o INVENTOR. .JA/w55 ,4. Spf-NGE@ BY /wvfC/L,

AUORNEY.

J. A. SPENCER CODE CONVERTER Jan. 14, 1941.

Filed Aug. 26, 1939 6 Sheets-Sheet 6 mummm INVENTOR, Jpn/CER' furl/WA.,

ATTORNEY.

Patented Jan. 14, 1941 PATENT OFFICE copE coNvEnTEn James A. Spencer. Teaneck, N. J., assigner to Radio Corporation of America, a corporation of Delaware Application August 26, 1939, Serial No. 292,051-

23 Claims. (Cl. 178-17) 'I'his invention relates to wire and wireless telegraphy.

An object of the invention is to provide automatic mechanism for changing signals from one code to another code.

Another object is to automatically change signals from a single-case code to a double-case code, that is, upper and lower case.

A further object is to provide means for autow matically changing signal of unequal length code to signals of equal length code.

More specifically, it is an object of the invention to provide means for automatically changing signals from cable code to Baudot code.

Additional objects will appear in the following description, reference being had to the drawings in which: l

Fig, 1 is a front elevation of the code converter,

certain parts being broken away to better illustrate the mechanism.

Fig. 2 is a rear elevation of the code converter, certain parts being omitted to simplify the illustration.

Fig. 3 is an end view of the converter.

Fig. 4 is a top view of the converter, certain parts being omitted.

Fig. 5 is a section of the mechanism for shifting the Creed code bars, taken along the lines 5-5 of Fig. 4.

Fig. 6 is a section taken on the lines 6-.6 of

Fig. 5.

Fig, 7 is a detail section of the switch operated by the shift mechanism.

Fig. 8 is a section showing the details for making an indication upon failure of the selection mechanism to operate.

Fig. 9 is a section taken along the line 9-*9 of Fig. 5 showing the details of the spacing'comb at either end of the cable code bar assembly.

Fig, 10 is a fragmentary perspective view of the operating mechanism'of the converter.

Fig. 11 is a diagrammatic top view of the cable selector bars and the Baudot selector bars showing the relative position of the slots in respect to the cross bars.

Fig. 12 is a diagram of the electrical circuit of the code converter.

Fig. 13 is a view of a section of tape containing perforations for cable code characters. ,liig. 14 is a front View of the shift bars.

Fig, 15 is an end view of the shift bars shown in Fig. 14.

Referring more particularly to Figs. 1 and 2, the code converting apparatus is mounted on plate I0, The selector head of the well known Creed printer is mounted on the base I I. It consists of an operating cam generally designated as I2 '(see also Figs. 3 and 10) for producing the desired selection movements. A motor, not shown, operates the cam shaft I2 and other movable parts 5 through shaft I2a and spiral gears I2b and I2c. 'Ihe Creed selector head contains a tape operating toothed wheel I3 fitting in the center holes of tape I4 positioned above a tape-track I5, omitted in Fig. 10. Beneath this tape-track is w positioned twenty pecker bars arranged in pairs, one pair, I6, I'I being shown in Figs, l and 10 the others being omitted.

All of the pecker bars are moved against the perforated tape by springs I8 shown in Fig. 1, 15 when lever I9 moves pin 20 by engagement of roller 2| with cam 22. The toothed tape wheel I3 is moved counter-clockwise, as shown in Fig. 10, by means of a rack I3', link 23, arm 24, arm 25, arm 26, roller 21 and cam slot 28. The arm 24 is 20 positively moved to the right by arm 25 but in the reverse direction it is yieldingly moved to the left by spring 29, arm 24 being pivoted tothe arm 25 at 30.

'Ihe rack I3' operates the toothed wheel I3 25 through gear 32 when the arm 20 moves to the right in Fig 10 but not when it moves to the left. This is accomplished by link 33 and bell crank lever 34 through engagement of roller 35 with cam surface 36, the bell crank being pivoted at the 30 point 3l.' The arm 38 of this bell crank lever has an'extension 39 secured thereto, as shown in Fig.

1 and Fig. 2, butomitted from Fig. 10 for clarity of illustration. The purpose of this extension 39 is to render theV tape feed inoperative during the 35 shift from upper to lower case and vice versa, and it will be referred to later in detail.

Since the number of elements in each cable code character is variable, the tape I4 must `be moved varying distances after each code character is 40 transmitted, `For example, in the transmitting position, the rst and fourth pecker bars will rise for letter A. In such position, the second, third, fifth, and seventh will rise for the letter B. Similarly the second,` third, sixthand seventh will rise 45 for the letter C. 'Ihis will be'apparentfrom inspection of the section of the perforated tape I4 shown in Fig. 13, where perforations above the center line of driving holes represent dots and perforations below such line represent dashes. 50 In between the characters there are no code perforations. Hence, the first pair of pecker bars after each code character cannot rise.

To permit-the feeding of the tape the varying distances required forthe code characters, lever 55 40 is moved upwards whenever any lever of each pair of levers, for example, Il and I1, is elevated. by springs I8 (Fig. 1). This arm is pivoted at 4I and has arm 42 extending into the path of rack I 3', Arm 40 is maintained in engagement with abutments 43, on the arms I6, I1, by spring 44 (Fig. 1).

When the perforated tape contains perforations for the letter A, for example, adjacent the wheel I3, arm 40 connected to the first two pairs ofl pecker levers will rise (see Fig. 13) because one pecker bar in each pair will, due to the perforations, rise. This will throw the arms 42 corresponding to the first two pecker bars out of the path of the rack I3', but the arms 4l for pecker bars at the third center perforation in Fig. 13 will not rise, as there are no code perforations at this point. Consequently, when the rack moves to the left in lowered position it can move the distance of two center holes only, the pivot 30 and spring connection 29 permitting this reduced movement, In the return movement to the right the rack will rise and feed the tape two perforations only when arm 25 engages arm 30.

If the letter B is the code character nearest the toothed wheel I3, levers 40 will rise and remove the arms 42 out of the path of the rack I3 corresponding to the first four pairs of pecker bars. The levers 40 corresponding to the ilfth pair of pecker bars, which are positioned at the driving hole for the space following the letter B will not rise. Therefore, the associated arm 42 will serve as an abutment to stop the rack in its movement to the left in lowered position. When the rack rises and returns to the right it therefore will move the tape the distance corresponding to ve feed holes or the length of the code for letter B. A

In the way described the tape is moved the correct amount for the transmitted character which always is the character nearest to the toothed wheel I3. While the pecker bars for succeeding characters rise throughout the remainder of the racetrack to the left in Fig. 10, in accordance with the succession of code characters in the message no signals are transmitting for them because of non-alignment of slots in the selector bars, as will be later apparent.

Whenever any pecker bar rises due to the presence of a code perforation in tape I4, it operates one of the levers 45 by means of lugs 48, 41, on each pecker bar between which the reduced ends slide freely in a longitudinal direction. Whenever a lever 45 is operated, the left-hand end (in Fig. 10) drops down into position to engage its corresponding lever arm 48, two only being shown.

In the disclosed embodiment I have provided for use of only fourteen of the twenty levers of the Creed selector head which with cooperating mechanism enables one to use a code of twenty-six alphabetical characters, the numerical characters and nine additional characters, as shown at the top of Fig. 11.

Accordingly there are only fourteen lever arms 48. Levers 45 are pivoted at 48 on frame 50 which itself is pivoted at I. Spring 52 resiliently urges frame 50 and levers 45 to the left in Fig. l0, but the frame is prevented from moving, except in proper timed relation, by cam 53 on cam shaft I2.

To permit the selector levers 45 to bring about the operation of the proper contact levers in the Baudot code apparatus, the lever arms 48 project into slots 54 in selector bars 55 mounted in a raceway 56, there being one selector bar for each lever arm 48. Consequently in the embodiment disclosed there are fourteen of these bars 65. There are no such lever arms and bars for the last six levers of the standard Creed selector head.A Obvlously these could be provided for the remaining six selector levers in apparatus designed for use of the entire cable code combination whenever desired.

By referring particularly to Fig. 5, it will be seen that the levers 4l are pivoted at l1 in frame members 5l secured to the sides of the raceway 5l, u indicated in Figs. 5 and 6, particularly.

It is preferable to separate each lever 4I from its adjoining levers and therefore I provide a comb arrangement consisting of a plate I6, having thin spaced plates 60 soldered or otherwise fastened in slots therein. These pla :s extend into thin milled slots 6I in the raceway 5l. Por clarity of illustration the thin plates Il are shown as lines having no thickness capable of being sectioned. Each of the cable code selector bars 55 is preferably likewise separated from its neighbors by a comb arrangement at each end of the raceway 55. This comb consists of a plate 52 in which are soldered or otherwise fastened thin plates 63, as shown in Fig. 9. These thin plates extend into milled slots 64 in the raceway 56 (Pig. 4). Narrow transverse bars 65 may be placed at each end and at the middle of the raceway 56 to lessen friction in the movement of bars 55. A series of transverse levers 66 are pivoted on a rod 61 extending through a hole 66 of each (Figs. l and l0). At the rear of the code converter, as shown in Fig. 2, the levers 66 are properly spaced by bushings 69 of the required thickness. The rod 61 is secured in the end plates 10, 1I and center plate 12. All of these plates act as frame members for the converter and are rigidly fastened to the bottom plate I0 by screws or other fastening means not shown.

For proper spacing of the cross levers 66 at the front part of the converter, as shown in Fig. 1, a slotted side plate 13 is fastened to the end plates and 1I. The spaces between the slots in the plate/13 will be the same as the thickness of the corresponding bushings 59 shown at the rear in Fig. 2. The center plate 12 may be slotted, as indicated at 14, for one of the cross bars 66. This center plate decreases in height and is foreshortened, as shown by the dotted line 12' and 12" in Fig. 3 so as to pass under the raceway 56 and provide room for parts to be later referred to.

Each transverse lever 66 has a hole or other means for securing a spring 16 for biasing it downwards. The other end of the spring is fastened in holes 11 or other means in a member 1l fastened to the base plate I0 (Figs. 1 and 3).

In Fig. l only seven of the springs 16 are shown so that other devices will not be obscured but it will be understood that each cross lever 56 has a tensioning spring 16. In Fig. 1 parts of the plate 13 and member 16 are broken away to illustrate parts that otherwise would be hidden from view.

For rigidly holding the end plates 10 and 1I and center plate 12 together, a cross member 19 is fastened thereto (Fig. 3). This cross member, springs 16 and member 18 are omitted from Fig. 2 for clarity of illustration.

Five slotted Baudot code bars l0, 8|, l2, Il, I4, extend across the code converter and are positioned in slots in the end plates 10, 1I (see particularly Fig. 4). End plates 10 and 1I have a projection or enlargement 85, 86, at the top front for formation of the slots for accommodating these Baudot code bars. Also positioned in slots in this enlargement are shift bars 91. 90. which provide for shifting from upper case to lower case or vice versa. These shift bars are required in making the code conversion because. as is well known, the cable code is a single case code whereas the Baudot code is a double case code.

Each of the Baudot code bars 00 to 94 rest on bell crank levers 89, 90 (Figs. 1 and l0). These bell crank levers are pivoted at 9|, 92, by small shafts extending from ears 93. 94, on the slotted bar 13, to similar ears 95, 96, on raceway 56 (Figs. 1, 5 and 8) but they may be pivoted in parts secured in any other way.

The cable code bars are slotted to permit one of the cross levers 66 to drop into aligned slots, there being in such position one or more ridges under all of the other bars to prevent their dropping at such time. .The Baudot code bars4 .are also slotted so that the proper ones will be lowered by the cross levers, as later described..

As is known, some of the characters of the .cable code contain other code characters.' For example, the letter A, consisting of a dot and a dash is contained in the letter J, which consists of a dot and three dashes. Consequently, if no provision were made for preventing it, when Acode character J is transmitted, code character A would also be transmitted. 'Ihe code character A is also contained in seven other code characters. Twenty-two other code characters also are contained in one or more other code characters, some of them, as E or T, twenty or more times. Multiple action in case of such characters is prevented by slotting the code bars so that when the cross lever for the longer of the code characters is operated by the aligned slots, there will be at least one ridge under the cross lever of the other character so' that it cannot drop. Fspe cial care has to be taken in slotting the code bars in this respect because the Creed selector head sets up a combination in the raceway for several characters simultaneously and if the movement of the bars is impeded, jamming would result.` For example, the letter E following the letter T or vice versa, would cause jamming of the code bars 55 if they were slotted without giving consideration to this matter. It is therefore necessary to permit movement of other bars 55 other than those of the transmitted code character.

In Fig. ll I have shown how the cable and Baudot code bars may be slotted to permit transmission of proper code characters without causing the cross lever or any other character to drop and without causing any cable code bars tofjam but this does not preclude the possibility of a different system of slots for correct operation. In this figure the forty-five cross levers 69 are not given a material thickness as it would complicate the illustration. Each cross bar is shown as a line. The cable and Baudot code bars are not separated from each other according to actual scale because this figure is diagrammatic to i1- lustrate only the relation of the slots and ridges to the cross levers, the ridges being indicated by heavy solid lines and the slots by spaces.

To indicate a failure of the cable code selector -head to respond to a signal, I have provided an extra cable code bar 91 (Figs. 8 and 10) in raceway 56. This extra code bar is so slotted that it normally presents a ridge 91' to each cross lever except the last one designated as 66a. Under this cross lever a slot is normally presented. When the extra code selector bar 91 is moved to the left, by means later described. slot is .pre-

sented under all of the cross lever '44 and a ridge 91" is presented under cross lever 94a (Flgrll). Thuswhenanyoneofthecrossleverslldrops due to aligned slots in the code bm u and l1.'

the mis-selection, as will later be described in.

detail. Y

The cam shaft I2' (Figs. 1 and 2) has a spiral l gear 99 meshing with a spiral gear 99 keyed to cross shaft |00. 'lfhis cross shaft is journalled in bearings |0|, |02 and center plate 12 which are secured to the base plate I0. The end plates 10 and' 1| have vertical slits |03 extending over the shaft |00 (Fig. 3) though these end plates could be used as bearings if desired. Shaft |00 has a thrust bearing |04 for taking care of the thrust produced by the spiral gears. Also, the bearing |0| may contain a thrust bearing. f

The shaft |00 has Atwo gears |05 keyed thereto which mesh with gears |06 fastened on a shaft |01 Journalled in the end plates 10, 1|, and center plate 12 (Fig. 4). Shaft |01 has at each end and in the center a cam |09 (Fig. B) for timed movement of operating cross bar |09 that holds the cross levers 96 and 65a in'proper elevated position and permits the selected one of such .levers to lower into the slots of the se- V lector bars 55 in proper timed relation (Fig. 10).

.end of lever ||1 is pivoted at ||9 to the misselection code bar 91 for producing the timed movement of that barwhen a cross lever 56 fails to operate, las previously referred to. The cams |08 `and ||5 are so positioned in respect to their cam followers ,that the cross bar |09 is lowered to permit operation of the selected cross lever 66 slightly prior to the release of follower ||6 from cam H5.

Power shaft |00 has spiral gears |20, 2|, meshing with spiral gears |22, |23, keyed to shafts |24, |25, respectively Fig. 2. Shaft |25 is the usual shaft of a teletypewriter transmitter |25 Well known in the art. This transmitter in addition to a start-stop cam (not shown) contains five switch operating lcams |21, only one of which is visible in Fig. 1. Referring particularly to Fig. 2, each cam operates a cam follower |28 by cam detent |29. The cam follower |28 ismounted on a bell crank switch lever |30. The switch 3| controlled by switch lever |30 is maintained in open position except when cam |21 presents cam slot |29 thereto, providing that catch |32 on pivoted lever |33 has been removed from engagement with the bell crank.l l Lever |33 extends into slot |34 in bar |35. A pivoted clip |36 at each side retains the end of the lever |33 in the slot when in proper position, the clips |36 being moved aside to permit the lever and slot to be shown. Bars |35, of which there are five, are pivoted in bell cranks 89 and 90 which are connected to the Baudot code bars 90 to 95, as previously described. It will thus be seen that each of the five code bars 66 to 65 controls its individual switch |3| on the teletypewriter transmitter in the same way that such switches are controlled by the usual typewriter keys of the teletypewriter transmitter as normally constituted. Reference character |31 indicates the well known locking-loop on the teletype transmitter for prevention of movement of levers |36 after the selection has been made, which is well understood in the art.

Shaft |24 operates the teletypewriter transmitter |38 which contains cams and switches similar to the teletypewriter transmitter |26. Parts in transmitter |38 that are similar to those of transmitter |26 have been given the same reference characters and description of these similar parts is not required. Transmitter |36 unlike transmitter |26 has a locking lever |33 for only one of the five switch levers |36 and this one is associated with No. 3 switch lever. Transmitter |26 sends out the Baudot pulses, both upper and lower case, for operating selector mechanism of the teletypewriter printer at the receiver and transmitter |38 produces the signal for shifting the printer mechanism from upper to lower case and vice versa. v

When locking lever |33 is disengaged from bell crank lever |30 the five bell crank levers of transmitter |38 are free to move and signal pulses one. two, three, four and five are sent out in one revolution of shaft |24. This is the signal to the receiver for the automatic shifting of the printer from upper to lower case. When locking lever |33 is in engagement with the third bell crank |30 the third switch |3| cannot close during the revolution of shaft |25 and during such revolution signal pulses one, two, four and five only, are transmitted. This produces the signal at the receiver for shifting from lower case to upper case.

The locking lever |33 for producing the shift from upper to lower case is pivoted in projection |40 by a slot arrangement similar to that already described in connection with locking lever |33 for transmitter |26. Projection |40 is secured to a cross bar |4| (Figs. 7 and 14). Bar |4| is pivoted to double bell crank levers |42, |43. The arms |44 and |45 of the double bell crank lever support shift bar 8l (Figs. 4, 14 and l5). The arms |46 and |41 of the double bell crank levers support shift bar 88.

When the position is as shown in Fig. 14 and any one of the upper case transverse levers 66 is operated, one only of these being shown, shift bar will be lowered and shift bar 88 will be raised. This will move bar |4| to the left and move locking lever |33 into position to prevent the movement of the third bell crank lever |30 when cam slot |29 is opposite cam follower |26. Therefore, when shift bar 8l is lowered by the operation of an upper case cross lever 66, the third pulse cannot be sent out from transmitter |38, but only pulses one, two, four and five. As is well known, this is the signal for producing a shift to upper case at the printer.

Whenever a lower case lever 66 (one only being shown in Fig. 14) is lowered by the selecting mechanism shift bar 88 will be lowered and shift bar 8l will be raised. The position will be as then indicated in Fig. 14. This action moves bar |4| to the right and moves locking lever |33 away from locking position in respect to the third switch lever. During the next rotation of shaft |25 signal pulses one, two, three, four and five will be sent out by transmitter |36. This produces the shift from upper to lower case at the printer.

The bar |4| extends through the end plate 'I6 (Figs. 3 and 7). This Proiectionhas a hump |46 between two notches |46 and |56 in which is seated a roller |6I. This roller is seated in notch |46 when the bar |4| is at the right in Fig. 14 and is in position for transmitting lower case characters and in notch |56 for transmitting upper case characters. As the bar |4| shifts from one position to the other, the roller |5| pass over the hump |46 and rotates the arm |5|' to which it is fastened. This movement rotates shaft |62 and arm |53 against tension of spring |54, the spring being fastened to an arm |54' on shaft |62 (Fis. 3). During this movement the switch lever |55 is released from engagement with the catch on arm |53, which opens the switch |56 in circuit with magnet |51. Magnet |51 has switch tongues |66, |56 (Fig. 12) engaging contacts |60, |6|, respectively, in the other position.

It was previously stated, in describing the raising and lowering of the rack I3 of the Creed selector head, that an extension 36 was fastened to arm 36. This extension ends in an upwardly extending post in position to be engaged by armature |63' (Fig. 1) when magnet |63" is energized. When the magnet |63 is energized arm 36 is forced downwards and held so that the roller 35 cannot follow the surface of cam 36. This disables the tape feeding arrangement by maintaining the rack out of engagement with the gear 32 during the shift cycle. This magnet is energized by closure of contacts |56 and |66 and also by a contact |64 in parallel therewith. Switch |64 is closed momentarily once during each revolution of shaft |24 by engagement of the cam hump |65 with the switch arm |66 (Figs. 2 and 12).

The operation of the code converter is as follows assuming the letters A and B are being sent in this order:

Let it be supposed that the tape |4 is in position in the Creed head so that the first feed hole |61 (Figs. 10 and 13) is midway between the last two pairs of pecker bars I6, I1, namely, the two shown in Fig. l0. There are ten f these pairs of pecker bars but only seven of them are utilized in the embodiment disclosed. This means that the pecker bars for the first seven feed holes, whenever selected, will operate the selector bars 55 by engaging the levers 45 with levers 46. At about this time cam 53 permits spring 52 to force selector levers 45 to the left in Fig. l0.

By inspecting Fig. 13 it will be seen that,

counting from the rear in Fig. l0, the first, fourth,'

eighth, ninth, eleventh and thirteenth selector bars will be moved to the right by this action. As will be evident from Fig. l0, movement of bars l and 4 will align the slots under the first lever 66 which is for the letter A. The selector bars are so slotted (see Fig. 11) that the movement of the other bars mentioned does not interfere with the desired selection. Lever 66 for the letter A will not immediately drop, as it is held in raised position by cross bar |06. Shortly after the slots are aligned cams |68 will permit the operating bail of which cross bar |63 is a part, to lower and cross arm 66 for letter A will immediately drop into the slot. Fig. 8. This takes place Just before the cam follower ||6 snaps of! of the abutment of cam I (Figs. 3 and 8). I

When the cam follower ||6 rode up on the surface of cam ||6 the mis-selection bar 6l was acter A and the cross bars 66 for al1 of the other characters exceptA cross bar 66d, for the mis-selection character. Under the latter cross bar, the

movement of the mis-selection bar, as referred to, placed a ridge. Since the supporting bar or ball |08 drops away from the cross levers 66 before follower ||6 leaves cam ||5, the cross bar for letter A dropped into its slot. Immediately thereafter the cam follower left cam but mlsselection bar 81 cannot move to the left under tension of its spring because the cross bar for letter A is in a slot and stops such movement.

Let it be supposed that the character previous to letter A was an upper case character. This means that shift bar 88 will be up and shift bar 81 down, Fig. 14. When cross lever 86 for the letter A dropped into the slots in the cable code bars 55, shift bar 88 was engaged and forced downwards. This moved catch |58 fromunder the operating arm |55 and opened switch contact "|56 (Fig. '1) which had been previously closedj when operating bail |08 raised the adjustable,

eccentric projection |68 fastened to the arm |I0 of the operating bail. The shifting of the bar |4| when bar 88 was engaged, also moved locking lever |88 from. engagement with the bell crank lever |80 of shift transmitter |38. 'I'his placed the third switch cam in operative position on transmitter |38 and a signal consisting of all live pulses is transmitted to the printer which will shift the printer platen in a well known way for printing lower case. i

The opening of contact |56 de-energized magnet |51 and interrupted the circuit of Baudot signal transmitter |26 at contact 6|. This disabled the Baudot signal transmitter for one revolution while the shift signal is going out over the line. It also opened its holding circuit at switch |60. The closure of switch |62 by deenergization of magnet |51 energized magnet |68" and stopped the tape feed. Closure of switch |63 closes the circuit of shift transmitter |88 so that the shift signal of the rst, second, fourth and fth pulses can be transmitted. Immediately after the fifth pulse of the shift signal is transmitted cam |65 on the shift transmitter shaft |24 (Fig. 2) closes switch |64 and re-energizes magnet |51. The circuit of shift transmitter |38 is interrupted and the circuit of signal transmitter |26 is closed, switch |56 having been previously closed by projection ,|68 on -the operating bail los.

When cross bar 66 for the letter A descended under tension of its spring into the slot of the cable code selector bars, Baudot code bars 83,

levers |33 from the fourth and fifth bell crank levers |30 of signal transmitter |26.,

The first described rotation of shafts |24 and |25 was devoted to the sending out of the shift signal, Baudot transmitter |26 and the cable code tape feed being disabled. In the next rotation transmitter |26 is in circuit and shift transmitter |38 is out of circuit. Consequently the moving of the fourth and fifth, locking levers closed the fourth and fifth switch contacts |8| as shaft |25 rotated. This sent out pulsesjfor the fourth and fifth positions in the revolution just as though the key for the letter A had been depressed on the usual teletypewriter transmitter. 'I'hls printed the letter A at the receiver.

The deenergization of magnet |63" in the shift operation permitted the roller 85 of the rack feed to engage cam 36 and the rack I8' to re-engage gear 82. On the movement of arm 24 to the left in Fig. the rack is returned until it engages the projection 42 corresponding to the feed space hole |68. Projection 42 was not moved because its associated pecker pins did not rise in the previous operation, there being no code perforations punched in the tape at this point.

On the movement of the arm 24 to the right the rack rotates the gear 3-2 and mov the tape so that feed hole |10 is directly between the first pair of pecker bars, namely, the two shown in Fig. 10. This will move the cable code selector bars 55 so that the cross lever 66 for the letter B will fall into the slots as soon as t'he bail |08 is dropped downward by the cam mechanism. Since the previous code character A was a lower case character the shift bars will be in the position code bars 80, 8| and 84, which will cause pulses to be sent out by the rst, fourth and iifth'switches in the teletylpe transmitter. This will print the letter B at the receiver.

If an upper case code character should be the next one on the tape for transmission it would engage bar 01 and force cross bar |4| to the left (Fig. 14) As the shift roller |48 passed the hump |48 it would open switch |58 in a way previously described and would transmit the shift signal through transmitter |88, interrupt the transmission of a signal by transmitter |26 and lock the feed rack to stop the movement of the perforated tape. As before, this will take up the time of one revolution of the transmitter shafts |24 and 25. On the next revolutionthe signal would be sent out for the code character which would print an upper case character at the printer because the shift signal of the rst, second, fourth and fifth pulses would have shifted the platen of the printer to the upper case position.

If it should happen that the selector bars are not moved to present an aligned slot to the cross levers 66, mis-selection bar 91 would move back to the left in Fig. 8 as soon as cam follower ||6 leaves cam ||5. This will present a slot to cross lever 66a. It will drop down and depress the third Baudot code bars (Fig. 11) Locking lever |38 will be released and transmitter |26 will send out the third pulse. This will cause the printer to print the mis-selection character which, by way of example, has been givenv as a Maltese cross. If a lower case code character had been previously sent, depression of bar 81 would delay the printing one revolution while the shift signal is being transmitted, as already described.

It will be seen that my invention provides for the automatic conversion of cable code signals into Baudot signals. As previously stated, if it is desired to use all of the cable code characters one could merely expand my converter to have sumcient levers and cable code selectors to accomplish this result and my invention is intended to provide for such an arrangement.

It will be apparent that one may use only one lcaml |08 for operating the cross bail |09 and that various other changes may be made. The detail construction disclosed has been merely for presenting a complete operative structure and changes may be made in the various parts withsaid stored signals in accordance with said two code groups.

2. In electric telegraphy, means for storing signals in a single group of code characters, each code character being different from the others, a

transmitter having means for sending signals in two code groups, a code character in one group being identical with one code character in the other group, additional means for transmission of a shift signal before transmitting a code character in one group after transmission of a preceding code character in the other group and means operated by said signal storing means for causing said transmitter tosend the stored signals and additional means to send said stored signals in accordance with said two code groups.

3. In electric telegraphy, a perforated tape containing stored signals in single case only, a transmitter having means to send said code characters in double case and having additional means for sending a shift signal when a transmitted code character of one case is followed by a code character of the other case and means operated by said tape for causing said transmitter to send the signals stored thereon by transmission of the double case and shift code signals.

4. In electric .telegraphs, a perforated tape containing a message in code characters of unequal length, a transmitter having means for sending code characters of equal length in upper and lower case and for sending shift signals upon changing from one case to the other and means operated by said tape for causing said transmitter to send said message in code characters of equal length.

5. In electric telegraphs, means for storing a message in code characters of unequal length, a transmitter having means for sending code characters of equal length in upper and lower case and for sending shift signals upon changing from one case to the other and means operated by said first mentioned means for causing said transmitter to send said message in code charac-ters of equal length.

6. In electric telegraphs, a transmitter having means to selectively transmit upper and lower case code characters, a transmitter having means to transmit upper and lower case shift signals, a perforated tape having a message stored thereon in single case code characters, means operated by said tape to cause the rst transmitter to transmit the said message in double case code characters and means for delaying the transmission of a code character by the rst transmitter when it has a different case from the preceding code character and for causing the second transmitter to transmit a shift signal, during such delay, indicating said different case.

7. In electric telegraphs, a signal circuit, a transmitter having means to selectively transmit upper and lower case code characters, each character having the same time period, a transmitter having means to transmit upper and lower case shift signals over said circuit, a perforated tape having a. message stored thereon in single case code characters, means operated by said tape to cause the first transmitter to transmit the said message in double case code characters over said circuit and means for disconnecting the first transmitter from said circuit when a code character has a different case from the preceding code character and for connecting the second transmitter to said circuit for transmission f a shift signal indicating said different case, and means for disconnecting the second transmitter from said circuit and connecting the rst transmitter thereto when the said shift signal has been transmitted.

8. In electric telegraphs, a signal circuit, a transmitter having means to selectively transmit upper and lower case code characters over said circuit, a transmitter having means to transmit upper and lower case shift signals over said circuit, a perforated tape having a message stored thereon in single case code characters, means operated by said tape to cause the first transmitter to transmit the said message in upper and lower case code characters over said circuit and means for disconnecting the first transmitter from said circuit when a code character has a different case from the preceding code character and for connecting the said transmitter to said circuit for transmission of a shift signal indicating said different case.

9. In apparatus for sending equal length code signals in double case, a signal circuit, a plurality of cams, switches in said circuit, arms operated by said cams for operating the switches, locking levers for preventing operation of the arms by said cams, a shift-signal transmitter, a tape having perforations representing unequal length code characters in single case, a plurality of selector bars for operating said locking levers to permit the cams to operate said arms, a code lever for each of the code characters extending transversely of the selector bars, a plurality of slotted selector bars, means operated by said tape for moving the slotted selector bars to present aligned slots under the code lever for the code character being transmitted from said tape, means to move a code lever into the aligned slots to depress certain of the first mentioned bars, an additional switch in said signal circuit and means operated by said code lever for operating said additional switch when the previously transmitted code character was of different case therefrom.

10. In apparatus for sending equal length code signals in double case, a signal circuit, a plurality of cams, switches in said circuit, arms operated by said cams for operating the switches sending said signals, locking levers for preventing operation of the arms by said cams, a shift signal transmitter, a tape having perforations representing unequal length code characters in single case, a plurality of selector bars for operating said locking levers to permit the cams to operate said arms, a code lever for each of the code characters extending transversely of the selector bars, a plurality of slotted selector bars, means operated by said tape for moving the slotted selector bars to present aligned slots under the code lever for the code character being transmitted from said tape, means to move a code lever into the aligned slots to depress certain of the first mentioned bars, an additional switch in said signal circuit and means operated by said code lever for operating said additional switch when the previously transmitted code character, was of different case therefrom, and to connect the said shift signal transmitter to the signal circuit.

11. In apparatus for sending equal length code signals in double case, a signal circuit, a first and second transmitter each having five signal cams and switches in said circuit, arms operated by said cams for operating the switches, five locking levers for preventing operation of the arms vby cams of first transmitter,'and a single locking lever for preventing operation of one arm only, by a cam of the second transmitter, a tape having perforations representing unequal length code characters in single case, a plurality of selector bars for selectively operating the five levers of the first transmitter to permit the cams to operate their arms for operating the switches, a code' lever for each of the code characters extending transversely of the selector bars, a plurality of slotted selector bars, means operated by said tape for moving the last mentioned selector bars to present aligned slots under the code lever` for the code character being transmitted from said tape, means to move the code lever into the aligned slots to depresscertain of the first mentioned bars, an additional switch connecting the first transmitter to said signal circuit and meansv operated by said code lever for opening said additional switch when the previously transmitted code character was of different case therefrom, connecting the second transmitter to the signal circuit and operating the single locking lever of said second transmitter.

12. In electrical telegraphy, a perforated tape for storing signals in a single group of code characters, each code character being different from the others, a transmitter having means for sending signals in'two groups of code characters, a code character in one group being identical with a code character in the other group, means operated by said tape for ycausing said transmitter to send signals stored thereon in accordance with said two code groups and means to cause said transmitter to transmit a mis-selection signal when the last mentioned means fails to operate.

13. In electrical telegraphy, a perforated tape for storing signals in a single group of code characters, each code character being diierent from the others, a transmitter having means'for sending signals in two groups of code characters, a code character in one group being identical with a code character in the other group,'means opy erated by said tape for causing said transmitter to send signals stored thereon in accordance with said two code groups and means to cause said transmitter to transmit a mis-selection signal when the last mentioned means fails to operate, and means to cause the mis-selection lever to enter the aligned slots andA depress certain of the first mentioned selector bars.

14. In apparatus for sending equal length code signals in double case, a signal circuit, a plurality of cams, switches in said circuit operated by said cams for sending said signals,1ocking levers for preventing operation of the switches by said cams, a shift-signal transmittena tape having perforations representing unequal length code characters in single case, a plurality of selector bars for operating said operating levers to permit the' cams to operate said switches, a code lever for each of the code characters, including a mis-selection character, extending transversely of the selector bars, a second plurality of slotted selector bars, means operated by said tape for moving the last mentioned selector bars to present an aligned slot under the code lever 'for the code character being transmitted from -said tape, means to move a code lever into ,the aligned slots to depress certain of the first mentioned bars, and means to align the slots in the last mentioned selector bars under the mis-selection code lever when none of the other code levers move into the slots aligned thereunder.

15. In apparatus for changing single case into double case code, a tape having perforations replever of the same case and to connect it thereto when it was by a code lever of different case.

16. In, apparatus for changing single case into double case code, a tape having perforations representing single case code characters, seeker pins positioned adjacent said tape, selector bars having a plurality of slots, a plurality of upper and lower case code levers extending across the selector bars, Vmeans operated by the seeker pins for moving the selector bars to align slots with one of the levers for each single case code character when the tape perforations therefor are in operating position, a pair of shift bars, one ex-` tending across the lower case code levers and the other across the upper case code levers, and means for sendinar a shift signal when either one of said shift bars is operated by a code lever.

17. In apparatus for changing single case into' double case code, a'tape having perforations representing single case code characters, seeker pins positioned adiacent said tape, selector bars having a plurality of slots, a plurality of upper and lower case code levers extending across the selector bars, means operated by the seeker pins for moving the selector bars to align slots with one of the levers for each code character when the tape perforations therefor are in operating position, a pair of shift bars, one extending across the lower case code levers and' the other across the upper case code levers, a transmitter for sending pulsesI in double case code. means operated by each of said levers for causing the transmitter to send pulses representing the code characters of the respective levers, and means operated by said shift bars for opening the circuit of said transmitter and sending a shift'signal.

18. In apparatus for changing single case into double case code, a tape having perforations representing single case code characters, seeker pins positioned adjacent said tape, selector bars having a plurality of slots, a plurality of upper and lower case code levers extending acrosstheselector bars, meansA operated by the seeker pins for moving the selector bars to align slots with one of the levers for each single case code character when the tape perforations therefor are in operating position, a shift signal switch, operating means for the switch, means to disconnect the operating code lever from said operating means when the previous operation was by/ a code lever of the same case, and to connect it thereto when it was by a code lever of different case, a signal transmitter for sending pulses in double case code, and means operated by each of said levers for causing the signal transmitter to immediately start the sending of pulses representing the code characters of the respective levers when the operating lever is disconnected from said operating means and to delay the sending of said pulses when it is connected thereto.

19. In apparatus for changing single case into double case code, a tape having perforations representing single case code characters, seeker pins positioned adjacent said tape, selector bars having a plurality of slots, a plurality of upper and lower case code levers extending across the selector bars, means operated by the seeker pins for moving the selector bars to align slots with one of the levers for each single case code character when the tape perforations therefor are in operating position, a shift signal switch, operating means for the switch, means to disconnect the operating code lever from said operating means when the previous operation was by a code lever of the same case and to connect it thereto when it was by a code lever of different case, a signal transmitter for sending pulses in double case code, a shift signal transmitter, and means operated by each of said levers for causing the signal transmitter to immediately start the sending of pulses representing the code charactersl of the respective levers when the operating code lever is disconnected from said operating means and to delay the sending of said pulses to cause the shift transmitter to send a shift signal when said operating code lever is connected thereto.

20. In apparatus for changing single case into double case code, a tape having perforations representing single case code characters, means for feeding the tape, seeker pins positioned adjacent said tape, selector bars having a plurality of slots, a plurality of upper and lower case code 40 levers extending across the selector bars, means operated by the seeker pins for moving the selector bars to align slots with one of the levers for each single case code character when the tape perforations therefor are in operating position, 45 a shift signal switch, operating means for said switch, means to disconnect the operating code lever from said operating means when the previous operation was by a code lever of the same,

case and to connect it thereto when it was by a 50 code lever of different case, and means for disabling the tape feeding means while the operating code lever is connected to said operating means.

21. In apparatus for changing single case into 55 double case code, a tape having perforations representing single case code characters, means for feeding the tape, seeker pins positioned adjacent said tape, selector bars having a plurality of slots, a plurality of upper and lower case code 50 levers extending across the selector bars, means operated by the seeker pins formoving the selector bars to align slots with one of the levers for each single case code character when the tape perforations therefor are in operating position, a shift signal switch, operating means for said switch, means to disconnect the operating code lever from said operating means when the previous operation was by a code lever of the same case and to connect it thereto when it was by a code lever of different case, a signal transmitter for sending pulses in double case code, a shift signal transmitter, means operated by each of said levers for causing the signal transmitter to send pulses representing the code characters of the respective levers when the operating lever is disconnected from said operating means and to cause the shift transmitter to send a shift signal when it is connected thereto, and means to disable the tape feeding means while the operating code lever is connected to said operating means.

22. In apparatus for changing single case into double case code, a tape having perforations representing single case code characters, means for feeding the tape, seeker pins positioned adjacent said tape, selector bars having a plurality of slots, a plurality of upper and lower case code levers extending across the selector bars, means operated by the seeker pins for moving the selector bars to align slots with one of the levers for each single case code character when the tape perforations therefor are in operating position, a pair of shift bars, one extending across the lower case code levers and the other across the upper case code levers, means for sending a shift signal when either one of said shift bars is operated by a code lever, and means for disabling the tape feeding means while the shift signal is being sent.

23. In apparatus for changing single case into double case code, a tape having perforations representing single case code characters, means for feeding the tape, seeker pins positioned adjacent said tape, selector bars having a plurality of slots, a plurality of upper and lower case code levers extending across the selector bars, means operated by the seeker pins for moving the selector bars to align slots with one of the levers for each code character when the tape perforations therefor are in operating position, a pair of shift bars, one extending across the lower case code levers and the other across the upper case code levers, a transmitter for sending pulses in double case code, means operated by each of said levers for causing the transmitter to send pulses representing the code characters of the respective levers, means operated by said shift bars for opening the circuit of said transmitter and sending a shift signal, and means for disabling the tape feeding means while the shift signal is being sent.

JAMES A. SPENCER.

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