US2099771A - Printing telegraph system - Google Patents

Description

Nav. 23, 1937. w. T. REA

PRINTING TELEGRAPH SYSTEM Filed April 11. 195e" 4 sheets-sheet 1 FIGA /N VEN TOR n. TREA BV A 7' TORNE V Nav. 23, 1937. w, T REA PRINTING TELEGRAPH SYSTEM Filed April l1l 1956 4 Sheets-Sheet. 2

fg/M( ATTORNEY Nav. 23, 1937. w. T. REA 2,099,771

PRINTING TELEGRAPH SYSTEM Filed April 11. 1936 4 Sheets-Sheet 3 /A/VENTOR W ZREA A 7'7'ORNE Y NOV. 23, 1937. w T, REA

PRINTING TELEGRAPH SYSTEM 4 Sheets-Sheet 4 Filed April ll. 1936 /NVEN/"OR W IRE/4 Patented Nov. 23, 1937 UNITED STATES PATENT OFFICE PRINTING TELEGRAPH SYSTEM Application April 11, 1936, Serial No. '13,944

10 Claims. (CL 178-30) 'I'his invention relates to telegraph systems and more particularly to printing telegraph systems wherein the actuation of a keyboard type transmitter at a sending station causes the transmission of signal impulses over a line circuit which are received at a receiving station and recorded thereat on a type-wheel printer.

In systems of this general type it has been common practice heretofore to utilize as the printing medium at the receiving station, a character bearing member or type-wheel whose periphery is equipped with characters corresponding to the letters of the alphabet and to the digits of our system of numbers and to cause such member to be rotated to a particular position with respect to a recording tape and there actuated in such a manner as to cause to be impressed on the tape the particular character corresponding to the particular position to which the wheel has been rotated. In such systems the type-wheel must be halted between the selection and printing operations and means must be provided for moving the recording tape intermittently between the printing of successive characters.

o Such requisites tend to complicate the receiving d circuit of limited band width.

It is the object of this invention to simplify and improve telegraph printers of the type-wheel variety and to reduce the maximum signal frequency necessary for a given sending speed.

This object is attained in accordance with a feature of the invention by utilizing as the printing medium in a telegraph receiver, a pair of character bearing wheels or discs whose peripheries are furnished with a series of characteristically formed edges and causing the wheels to be rotated relative to each other in such-a manner, and to come into engagement at such times, that the point of intersection of the two cooperating edges will describe, in the plane defined by the two edges, the outline of a symbol such as a letter of the alphabet or a numeral.

Another feature of the invention is embodied in the use of a letter or character pattern which renders it possible for parts of the pattern to be used in forming more than one of the characters so that an overlay" between characters is attained and the shortest actuating signal pulse is permitted to be long relative to the total time of rotation of the operating members. This feature causes the maximum signal frequency necessary for a given speed of sending to be reduced to approximately half the signal frequency necessary in the usual form of type-wheel printer.

A further feature of the invention resides in the use of means for eiecting the synchronous operation of the two character bearing wheels and for causing to be drawn between their cooperating edges, during a printing operation, a receiving medium, such as carbon paper or an inked ribbon.

A still further feature of the invention is embodied in a suitable keyboard type telegraph transmitter which is so designed as to be capable of controlling the operation of the receiving mechanism so as to cause it to function in such a manner as to cause to be printed on a moving tape the character or characters corresponding to the key or keys utilized in transmitting a mes- Sage.

In the proposed form of the invention illus-I trated in the drawings, two character wheels or discs are employed in the receiver, the axes of which are at right angles to each other and each in the plane of the opposing wheel, on the peripheries of which are formed a series of characteristically shaped ridges. When the wheels are rotated synchronously and their peripheries caused to make mutual contact, the point of intersection of the ridges will cause to be inscribed, on a paper tape moving between them, a symbol or character whose formation is determined by the pattern of the ridges contacting. 'I'he point at which the rotating discs or wheels are brought into engagement and the time duration of this engagement, which determine the form of the particular character traced on the tape, are themselves determined by the design of suitable cams associated with the transmitting mechanism and their location on a common transmitter cylinder with respect to the home or normal position thereof.

The invention will be readily understood from the following detailed description made with reference to the accompanying drawings, in which:

Figure 1 is a schematic representation illustrating a pair of elements whose longitudinal axes are at right angles to each other and whose edges are in contiguity at a particular point. 'I'he two Clements of this figure correspond to the characteristically shaped edges located on the typewheels employed in the present invention;

Figs. 2 and 3 constitute plan views of the perlpheries of the type-wheels showing the characteristically shaped ridges located thereon;

Fig. 4 illustrates a design pattern out of which may be formed all the letters of the alphabet and the numbers to nine;

Fig. 5 illustratesthe nine symbols which may be produced by the character wheels of this invention. This figure is labled by the numerals from 1 to 73 to indicate its order of formation. It will be noted that any letter or digit may be abstracted from the figure by starting and stopping at the proper places. For example, the letter S is formed by the lines from 3 to 9, the figure 6 is formed by the lines from I to 8, and the letter X is formed by the lines 59 to 63;

Fig. 6 shows the character wheel printer letter and digit forms as'they appear when printed on a recording tape;

Figs. 7A, 7B and 7C illustrate the manner inv which a particular letter, such as D, is formed by a particular set of characteristically shaped edges on the character wheels of this invention;

Fig. 8 is a skeletonizecl perspective view of the operating mechanism employed in the receiving device or printer of which the particular type of character bearing wheels form a part;

Fig. 9 is a skeletonized perspective view of the transmitting mechanism which controls the operation of the receiver of Fig. 8;

Fig. 10 is a graphic illustration of the line signals corresponding to each letterand digit capable of being transmittedf by the transmitting mechanism; and

Figs. 11 to 15, inclusive, illustrate five successive stages in a complete cycle of operation of-the printer mechanism. Fig. 11 shows the normal condition of the printer; Fig. 12 illustrates the printer at the start of its movement; Fig. 13 shows the printer mechanism during the printing operation; Fig. 14 shows the printer mechanism immediately after the printing operation has been performed, and Fig. 15 illustrates the printer just asit is about to assume its normal condition.

The transmitter The transmitting mechanism utilized in the system herein disclosed is illustrated in Fig. 9 and includes a cylinder I0 which is divided into thirtyfour annular sections I I, each of which is provided on its periphery with a cam or elevated portion I2. The location of the cams I2 on the cylin- I der with respect to the home or normal position of the cylinder and their lengths have a special significance in that they determine the formation of the various characters. 'Ihe cylinder I0 is suitably mounted on a shaft I3 and is cradled within the yoke piece I4 which is pivotally supported on the axis of the drive shaft I5. A pair of control springs I6 is located in such a position as to be within the line of travel of projection 2| of the yoke I 4. These springs function to control the operating magnets of the receiving mechanism in a manner to be hereinafter described.

The transmitter includes a keyboard comprising thirty-four lever type keys I1, only two of which are shown complete, and a. space bar 1. Twenty-six of the keys are allotted to the letters of the alphabet and eight to the numerals 2 to 9, inclusive. The keys I and O are employed in effecting the printing of the letters I and O and also the numbers 1 and 0. 'Ihe key levers are pivotally mounted on a shaft I8 and are each provided with an integral projection I9 extending therefrom at right angles to the longitudinal axis of the key lever. Each of the projections I9 is in alignment with a cylinder section II and cooperates with the respective cylinder cams I2 in such manner as to determine the time at which the receiving mechanism starts to print a character and the time duration of such printing operation.

A cam 22 is located at one end of the cylinder I0 and is rigidly associated therewith. This cam is provided with a camming elevation 23 which, when the cylinder is in its normal or home position, rests upon a stop 24 which is rigidly fixed in any suitable manner. The engagement of elevation 23 with stop 24 when the cylinder I0 is in its normal position, causes the cylinder I0 and yoke piece I4 to be raised in such a manner as to cause the end 2| to bear upon and maintain the longer of the contact springs I6 in engagement with the shorter one. The contact springs I6 are, therefore, closed when the transmitter is in its normal y position.

A continuously operating constant speed motor 25 drives the shaft I5 through a friction clutch 26. Rigidly secured to the drive shaft I5 are stop cam 21, latch cams 28, 29 and gear 30, the last meshing with gear 3| i'lxedly mounted on shaft I3. The purpose of this apparatus will appear from a later description.

Each key lever extends rearwardly beyond its projection I9 to form alledge which, when a key is actuated, engages the under side of the elongated bar 20 which is common to all the keys. 'I'he actuation of a key I1 and the ensuing upward movement of bar 20 causes bell crank 33, one end of which is permanently associated with the bar 20 or may be integral therewith, to pivot about the axis 34. Pivotally associated with the bell crank 33 is a slotted cam 36 which is adapted to ride on the xed pin 6 and to move in the direction indicated by the arrow when actuated by the bell crank. This movement of the element 36 causes pawl 31 to pivot on its axis and move out of engagement. with the straight portion of stop cam 21 whereupon the drive shaft I5 is released and rotates. The upper edge of pawl now rides on the camming surface of cam 2l being held in contact therewith by the action of spring 39. The cam 36 is so designed as to release the pawl 31 when the cam reaches the limit of its forward travel thereby permitting the pawl to be in a position such as to engage the cam 21 when the latter completes a revolution. 'I'he cam 21, therefore, under the influence of motor 25 rotates in the direction indicated by the arrow thereon for one complete revolution whence the straight edge thereof again is engaged by the working end of pawl 31. The cam 21 and drive shaft I5 are, therefore, arrested and held against further rotation.

As a key I1 is depressed, a lug 40 on the inner end of the key lever moves upwardly, clearing the edge of latch plate 4I. As the shaft I5 rotates,

cam 28 xed thereto, acts upon the lever 42 tor tion that the latch plate 4I when actuated, moves between the lug 48 of an actuated key lever and the corresponding lugs of all other key levers thereby locking the actuated lever in its operated position and preventing the actuation of all other levers.

Due to the engagement of gears 30 and 3l and when the cam 21 is released, the cylinder II) starts to rotate in the direction indicated by the arrow on cam 22. The elevation 23 of cam 22 accordingly rides off the stop 24 permitting the cylinder I8 and its associated yoke piece I4 to fall, so that the periphery of the cylinder section Il corresponding to the actuated key I1 engages the projection I9 thereof. This movement of yoke I4 causes its end 2l to raise whereupon the Contact springs are opened for a purpose which will appear from a later description. As the cylinder I0 rotates, the spring contacts I6 remain open until the elevated portion or cam I2 reaches the projection I9 of the actuated key lever whereupon the cylinder I8 and yoke piece I4 are again raised and the contact springs I6 again actuated to effect a circuit closure. The duration of this circuit closure depends upon the peripheral length of the cam I2. When the cam I2 rides off the projection I9 due to the continued rotation of cylinder I8, the latter and its yoke piece I4 are again lowered to cause the contact springs I6 to be opened and they remain open until the raised portion 23 of cam 22 again rides upon the stop 24, when. the cylinder I0 and its yoke I4 are raised to effect a circuit closure by way of the contact springs I6. The cylinder III is then in its home or normal position.

Just prior to the cylinder I8 reaching its home position, the latch cams 28 and 29 act upon the levers 42 and 45, respectively, permitting their upper ends to fall into the cam notches under the action of springs 50. 'I'his movement of the levers 42 and 45 causes the latch plate 4I to be withdrawn from its latching position whereupon the actuated key I1 is restored to normal by the action of a suitable restoring means, not shown.

As the latch plate 4I is withdrawn and the key lever restored to normal position, the bar 28 is returned to its normal position under the action of spring 52. 'I'he bell crank 33 accordingly pivots on its axis 34 causing the notched cam 36 to move in a direction opposite to that indicated by the arrow and assume a position such that it will arrest any further pivotal movement of pawl 31 when the latter is engaged by the straight portion of cam 21. 'I'he transmitter mechanism is accordingly restored to normal position of rest and the rotational energy generated by the motor 25 is dissipated in the friction clutch 26.

The receiver Referring now to the receiving mechanism shown in Fig. 8, there is disclosed a continuously operating constant speed motor 60 which drives shaft section 6I through a friction clutch 62. Normally, that is, when the transmitter shown in Fig. 9 is not functioning, that portion of the friction clutch 62 associated with shaft section 6I abuts against the latching armature 64 of the electromagnet 65 so that the shaft section 6| is normally at rest. The drive shaft comprises the section 6I and section 66 connected together by the flexible coupling 61 so that the section 66 may be moved angularly with respect to the section 6 I. On the extreme end of shaft section 66 there is rigidly fixed a character bearing wheel or disc 68. An electromagnet 69 is provided with an armature 18 which terminates in a depending yoke-like portion which supports the outer end of shaft section 66. As will appear from a general description of the operation of the system to be made hereinafter, the magnets 65 and 69 are normally operated so that the armature of the former is in such a position as to effectively prevent rotation of the shaft sections 6I and 66 and the armature of the latter is in such a position that the shaft portion 66 and the type-wheel 68 are in their lowermost position.

With its axis at right angles to the axis of wheel 68 there is mounted on a suitable shaft 12 a type-wheel or disc 13 which is adapted to be driven by shaft section 6I through gears 14, 15, sprocket wheels 16 and 11, and drive chain 18.

The shaft section 6I has rigidly fixed thereon a Worm which meshes with the worm wheel 8| mounted on shaft 82 which carries a fixed Worm 83 at its lower end. The worm 83 meshes with worm gear 84 so that the latter is driven by the shaft section 6I also. Mounted on suitable shafts are a paper tape supply reel 86 and a paper takeup reel 81, the latter being driven from the shaft of worm gear 84 by means of belt 88. The paper tape passes from the supply reel 86 over a pulley 96, between the two type- wheels 13 and 68, over a driving pulley 5 mounted on the shaft of worm gear 84 and thence on the paper take-up reel 81. The supply and take-up reels 86 and 81 are permitted to slip relative to their respective shafts in order to insure a uniform movement of the tape between the type- wheels 68 and 13 when the diameters of the reels vary as the tape is transferred from one to the other. The rate of movement of the tape 89 bears a. predetermined relation to the rate of movement of the peripheries of the character wheels. A carbon or inked ribbon is fed from the reel 96 over pulley 91, passed between the tape 89 and type-Wheel 68, over pulley 98 to the take-up reel 99. It is to be understood that the shaft upon which reel 99 is mounted may be driven at a constant speed in any suitable manner from the shaft 6I.

It will be apparent from the foregoing description that when magnet 65 is deenergized, the armature pivots about its axis 92 under the action of spring 93 and moves out of engagement with the stop portion of friction clutch 62. 'I'he shaft sections 6I and 66 thereupon rotate causing the type- Wheels 68 and 13 to be driven synchronously and the tape 89 to be drawn between the two cooperating peripheries thereof under the influence of pulley 5.

A general description of the operation of the system will now be had, specific reference being made to Figs. 10 to vl5, inclusive.

Fig. 10 may be considered to correspond to the periphery of the cylinder I0, the heavy horizontal lines thereof representing the cam surfaces I2 of the cylinder. As hereinbefore stated, the length of a cam surface I2 and its position on the cylinder relative to the start or home position of the cylinder determines the character which Will be printed at the receiving end. In the present description it will be assumed that it is desirable to transmit to the receiver the letter D.

Prior to the transmission of a character signal, the magnets 65 and 69 are in their normal energized condition due to the closure of contact springs I6 which cause ground to be connected to conductor |00 to complete an energizing circuit for the magnets of the receiver. This condition is illustrated by Fig. 1l. In this position of the receiver, the character wheels are, as shown in Fig.

8, in such position that they do not bear on the recording tape due to each wheel being furnished with a flat space on the periphery thereof. The at space on wheel 13 is clearly indicated at 4.

To transmit the letter D or rather to cause the letter D to be printed at the receiving station, an operator would depress a key identified by the letter D causing the release of stopcam 21 in a manner hereinbefore described. 'I'he transmitter shaft and cylinder IU would accordingly start to rotate. As the elevation 23 of cam 22 rides oi the stop 24, the cylinder I 0 and its yoke piece I4 are lowered causing contact springs I6 to be separated and the magnets 65 and 69 to be deenergized. The deenergization of these magnets occurs substantially simultaneously with the start of rotation of cylinder II). Magnet 65, deenergized, releases its armature causing it to move out of engagement with the stop element of friction clutch 62 whereupon drive shaft 6I and associated mechanism begin to function under the action of motor 60. The thirty-five superimposed short lines shown at the extreme right of Fig. 10 correspond to the raised portion 23 of cam 22, it being understood that the cam 22 functions for the entire cylinder when the latter is in its home position. As the cylinder continues to rotate the projection I9 of g the actuated key I1 rides on the periphery of the annular portion in alignment therewith until it meets a cam I2. The peripheral portion of the cylinder traversed by the projection I9 up to this time corresponds to the selection period and is indicated by the broken line a-b of Fig. 10, it being understood that the selection period be-l gins at a, that is, when the cam 23 rides off the stop 24.

During this period of selection the type-wheel 68 is in its raised positon due to the deenergization of magnet 69 so that the paper tape 89 and inked ribbon 95 pass freely between the two type- Wheels, that is, no impression is made on the tape, due to the separation of the type-wheels.

This condition or stage is represented by Fig. 12.

When the projection I9 of a depressed key I1 engages the cylinder cam I2 in alignment therewith, the printing operation starts and continues until the cam I2 passes beyond the inuence of the projection I9. During this period, magnets 65 and 69 are energized, the latter causing the type- wheels 68 and 13 to come into engagement. During the period that projection I9 is riding on a cam surface I2, which period is termed the printingperiod and corresponds to the distance b-c shown in Fig. 10, certain portions of the characteristically formed peripheries of the typewheels are pressed together with only the traveling tape 89 and inked ribbon 95 intervening, with the result that the letter D is traced upon the tape, it being understood that during the selection period the type-wheels have advanced until a particular set of characteristically formed edges on the peripheries thereof have been positioned opposite to one another and which edges cooperate to form the letter "D as the tape is drawn between the cooperating edges. 'Ihe printing period is shown in Fig. 13.

As the key lever projection I9 moves oi the cam portion I2 of the cylinder III, the cylinder and its yoke piece I4 are again lowered causing the deenergization of the magnets 65 and 69. 'I'he deenergization of magnet 69 at this time causes the type wheel 68 to be drawn upwardly away from the type-wheel 13 allowing the paper tape to be drawn freely therebetween without any impression being made thereon. This condition is illustrated by Fig. 14 and persists until the latch cams 28 and 29 of the transmitter function to release the actuated key and permit the restoration to normal oi' bar 20 under the action of spring 52. The release of the bar20 causes the bell crank 33, notched cam 36 and pawl 31 to `coi'unction in such a manner that the pawl 31 is in a-position to engage the straight portion of stop cam 21 which results in the arrest of the transmitter. 'I'his condition is illustrated at Fig. 15 and the peripheral distance traversed during this time (after printing) by the key projection I9 is indicated by the broken line c-d of Fig. 10.

Just as the transmitter is coming to rest, or

approaching its home position, the raised por-n tion 23 of cam 22 rides upon the s'top 24 causing cylinder I0 and its yoke piece I4 to be raised with the result that the contact springs I6 are again closed. The closure of the springs I6 at this time causes magnets 65 and 69 to be energized with the result that the armature stop of the former is moved into such a position as to engage the stop portion of friction clutch 62 whereupon the receiving mechanism is brought to rest and the equipment is restored to its normal condition.

As just described and as illustrated by the broken line a-b-c-d-a of Fig. 10, there are three active phases in the cycle oi operations required in the printing of a character. First, the selection period, which in the case described, extends between the points a and b on the broken line of Fig. 10. The extent of this selection period varies in accordance with the location of the camming element I2 on the periphery of the Icylinder I0 with respect to the cylinders home position or starting point.

y The second is the printing period extending between the points b and c on the broken line of Fig. 10. The length of `this period varies with the length of the cam I2 employed, and the last, is the period after printing, represented by` that portion of the heavy line in Fig. l0 between the points c and d.

With further reference to Figs. 2 and 3, it will be noted that the particular characteristically formed ridges labeled IIIl and III on the peripheries of type wheels 68 and 13, respectively, are those which, when brought together, cooperate in forming the letter D. This isapparent from the enlarged representations illustrated in Figs. 7A, 7B and 7C. The peripheral X' indicate those portions of the type-wheel peripheries which will have passed each other before the projection I9 of the actuated key lever I1 comes into engagement with the elevated portion or cam I2 on the section of cylinder I0 which is in alignment with the actuated key. 'I'his is known as the selection period of the cycle and corresponds to the portion of the broken line in Fig. 10 extending between the points a and b. The' peripheral lengths Y and Y indicate those portions of the type-wheel peripheries which are in 'contact during the printing period due to the operation of magnet 69 which is effected by the engagement of the key lever projection I9 with a cam surface I2 and the consequent closure of the Contact springs I6. The interval of time during -which the projection I9 and a cam I2 are in contact depends upon the length of time during which the contact springs I6 are maintained closed which in turn depends upon the length of the cam surface I2.

The peripheral lengths Z" and Z indicate those portions of the type-wheel peripheries lengths X and which freely pass each other after the printing of a character has been accomplished and correspond to the period of the cycle represented by the portion c-d of the broken line in Fig. 10. During this period, the key lever projection I9 is in contact with the deeper portion of the cylinder section II intermediate the cam I2 andthe point corresponding to the home position of the cylinder I0, the contacts I6 separated and magnet 69 deenergized.

To more clearly illustrate the actual printing of a character, the sketches 1A, 'IB and 1C are submitted, which combine to disclose the manner in which the characteristically formed ridges III) and III (Figs. 2 and 3) cooperate in tracing the letter D. The point indicated Start in Fig. 7A corresponds to the points a of Figs. 2 and 3 at which the characteristically formed ridges IIO and III of the type- wheels 68 and 13, respec tively, come into contact with each other. AS the type-wheels advance, the edges defined by the characteristically formed ridges H and III Wipe over each other causing to be traced on the paper tape moving between the two wheels, the character D. Fig. 7A illustrates the start of the wiping engagement. Fig. '7B that portion of the letter D which is completed after the two edges have partially passed each other and Fig. 7C, the end of the printing cycle when the tracing of the character is completed. The small numerals shown on the patterns III) and III of Figs. 7A, 7B and 7C, serve to dene those portions of the edges which cooperate in tracing the particular elements of which the letter Dis composed. The edge portions between the numerals l and 2 cooperate in tracing the upward vertical line of the letter D; the portions located between the numerals 2 and 3 eiect the tracing of the upper horizontal line of the letter; the portions deiined by the numerals 3 and 4 trace the upper curve in the letter; the portions between the numerals 4 and 5 cooperate in tracing the vertical line extending. downwardly from the upper curved portion of the letter; the

' portions located between the numerals 5 and 6 eiect the tracing of the lower curve and the portions B to l trace the lower horizontal line of the letter D. It will be noted that the symbol forming pattern progresses from right to left as the wheels rotate in order to compensate for the motion of the tape during the rotation of the wheels.

It is to be understood that the connection between the transmitting contacts and receiving magnets may be any well-known form of transmission circuit, such as telegraph, telephone or radio.

The device herein described, though resembling in some respects a type-wheel printer, has the advantagel thereover, that a simple operation of the receiving magnet during the rotation of the receiving mechanism causes a letter or character to be formed. In other words, it is not necessary to halt the character-bearing member or members during the printing operation, nor is it necessary that means be provided for moving the tape intermittently between characters. This results in a simplification of the mechanism. A further important feature of the device of this invention, as hereinbefore mentioned, provides for a lower maximum signal frequency for a given sending speed.

Though the invention has been disclosed in a particular embodiment, it is conceivable that it may assume other forms. For example, two

hollow cylinders having their axes at an angle to each other and in the same relation to each other as the character wheels referred to above may be employed. Around each cylinder wall characteristically shaped slits or apertures may be provided. Positioned within the first cylinder a stationary light source and a lens system would be provided for directing a beam of light through.

the apertures in the cylinder. Within the second cylinder a light sensitive medium, such as a strip of photographic paper, may be caused to move parallel to the axis of the cylinder and also Within this cylinder and interposed between the sensitive medium and the light source, a second lens system is provided with causes the light beam passing through the two cylinder apertures to be concentrated in a point on the sensitive medium. 'Ihe two cylinders may be caused to revolve in synchronism and the light source may be controlled in any suitable manner by line impulses.

The operating principle of this arrangement is the same as the character-wheel embodiment, i. e., when the cylinders are rotated at equal velocities and the light source is illuminated,the moving point of intersection of the slits in the cylinders, which are in the range of the beam of light, will trace a symbol or character on the light-sensitive surface.

What is claimed is:

1. In a telegraph printer, a pair of continuously rotating discs having irregular peripheral edges, a moving recording tape interposed between the peripheral edges of said discs and means for causing the peripheral edges of said discs to contact said moving tape at certain intervals during the rotation of said discs whereby said tape is acted upon by the contacting portions of the peripheral edges to cause a symbol, characteristic of the contacting portions of the peripheral edges, to be traced on said tape.

2. In a telegraph printing system, a pair of continuously rotating discs having irregular peripheral edges, a moving recording tape interposed between the peripheral edges of said discs, and means for selectively positioning certain portions of the peripheral edges of said discs into cooperative association with said tape and means for actuating one of said discs to cause the selected portions of the peripheral edges of said discs to contact said tape whereby said tape is acted upon by the selected portions of the peripheral edges of said discs to cause a definite char acter to be traced on said tape.

3. In a telegraph printing system, the combination of a printer having a pair of rotatable discs each of whose peripheries bears a series of characteristically shaped ridges and which cooperate by mutual contact to trace on a tape moving between their peripheries symbols whose formation is determined by the peripheral points in contact and the time duration of such contact, an electromagnet adapted to effect the contacting of said discs and transmitter means for transmitting current impulses of predetermined diiierent durations and at predetermined intervals during the rotation of said discs to cause the operation of said electromagnet accordingly.

4. In a telegraph printer, a pair of continuously rotating discs, the axis of each of said discs being in the plane of the other disc and at right angles to the axis of the other disc, a characteristically shaped ridge on the periphery of each of said discs, a recording tape moving freely between said discs in a direction at right angles to the plane of one of said discs and means for effecting an operative association of said discs whereby the edges of the characteristically shaped ridges of said discs make mutual contact through said moving tape to cause to be traced on said tape a symbol whose form is determined by the characteristic shapes of the edges in contact.

5. In a telegraph printer, a pair of continuously rotating discs, the axis of each of said discs being in the plane of the other disc and at right angles to the axis of the other disc, a plurality of characteristically shaped ridges on the periphery of each of said discs, a recording tape moving freely between said discs and whose line of travel is parallel to the axis of one of said discs and means for moving one of said discs to cause the edge of certain of the characteristically shaped ridges thereof to contact, through said tape, the edge of certain of the characteristically shaped ridges of the other disc whereby the movement of said tape between the two contacting edges causes to be traced on said tape a symbol whose form is determined by the characteristically shaped ridges in contact.

6. In a telegraph printer a pair of continuously moving elements, a plurality of characteristically shaped ridges on each element, a symbol recording tape moving therebetween, said elements moving in such a manner that the respective ridges move in planes substantially parallel to the tape and at right angles to each other and means for bringingsaid elements together without interrupting their motion so that the ridges make contact with and trace a symbol on the tape in accordance with the shape of the cooperating ridges in contact therewith.

7. In a system for tracing letters or symbols, a pair oi' opposed characteristically shaped scribing edges, a tape or other recording medium therebetween, means for moving the tape at a. constant rate, means for moving said edges at right angles td each other and substantially parallel to said tape at a constant rate and means for simultaneously bringing said opposed edges into engagement with the tape for a predetermined interval withoutinterrupting their parallel movement or the movement of the tape.

8. In a system for tracing letters or symbols, a pair of tracing elements in contact with each other at one point, a tape or other recording medium therebetween, means for moving said recording medium between said elements and means for synchronously moving said elements at right angles to each other without breaking the contact therebetween, said elements being so shaped that said synchronous motion causes the point of contact to shift with respect to the moving record medium, thereby tracing a legible character.`

9. The method of tracing symbols on a moving tape or recording medium bymeans of a pair of scribing edges which comprises causing the scribing edges to be moved at right angles to each other and in planes substantially parallel to the recording medium, driving the recording medium between the scribing edges and causing said scribing edges to contact the recording medium in accordance with a predeterminedpattern.

10. The method of tracing symbols on a moving tape or recording medium by means of a pair of scribing edges which comprises passing the recording medium between the scribing edges, causing the scribing edges to contact the recording medium and moving each of said scribing edges at right angles to each other over the recording medium while in contact therewith, in accordance with a predetermined pattern.

WILTON TREAT REA.

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