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July 9, 1946, J. N._ ANDERSON 2,403,472 _ APPARATUS FOR RECORDING ELECTRICAL SIGNALS Filed Oct. 2, 1942 mL@vom _ \ _ _ @A_ 3 Sheets-Sheet l July 9, 1946. ' J. N. ANDERSON - _ 2,403,472 APPARATUS FOR RECORDING ELECTRICAL SIGNALS Filed Oct. 2, 1942 - I 3 Sheets-Sheet 2 _ '9 è. (CI-"inning: «www MII ” INVENTOR J. N. ANDERSON ATTORNEY July 9, 1946. J. N. ANDERSON 2,403,472 APPARATUS FOR RECORDING ELECTRICAL SIGNALS Filed Oct. 2, 1942 5 Sheets-Sheet 5 INVENTOR J. MANDERSON ÄTTORN EY y Patented July 9, 1946 ` 2,403,472 UNITED STATES PATENT OFFICE James N. Anderson, North Plainfield, N. J., as signor to The Western Union Telegraph Com pany, New York, N. Y., a corporation of New York 1 Application October 2, 1942, Serial No. 460,530 7 Claims. (Cl. 23d-#70)l 2 This invention relates generally to an improved l apparatus for recording electrical signals, and more particularly to the recordation and repro duction of pictures, drawings, writing and other subject matter, in facsimile or otherwise, by means of a stylus which causes marking impacts to be applied to a record receiving medium to delineate a record thereon in accordance with re it has been found diillcult to control the degree of pressure with which the stylus engages’or im pacts the record sheet, the pressure exerted by the stylus often varying in accordance with vari ations in the signal strength oi.' the received marking currents. Moreover, in- prior devices it has been diillcult to obtain the desired power nec essary for cutting stencils or producing multiple ceived electrical signals. The invention is par copies without undesirably increasing the levels ticularly adapted, although not limited, to the 10 of the signal currents transmitted, and also diiii facsimile production of a master copy of an origi nal from which numerous other copies may be cult to provide a desired uniform power level of the currents which actuate the recording devices, and the amplitude of the stylus swing and the frequency respcnse characteristic of the units made by the mimeograph, hectograph and other printing processes. In accordance with the present invention the subject matter may be transmitted by facsimile or other signals generated in accordance with the subject matter to be recorded or reproduced, and were not uniform, particularly when producing stencils or multiple copies of the received sub ject matter. _ One of the objects of the present invention is in the case of subject matter appearing on an to provide a suitable recording unit in which the original sheet or blank, this'may be reproduced in 20 force of the impacts imparted by the stylus to the facsimile upon a record receiving blank. The record receiving sheet is maintained constant, record receiving blank may, if desired, comprise irrespective of variations in the signal level or a stencil or other master blank from which a amplitude of the received marking currents, thereby to produce uniform density and sharp large number of copies may be made by various known printing or other duplicating processes, or 25 definition of the recorded subject matter. the recording may be eil‘ected upon a single blank Another object of the invention is percussion or simultaneously upon a number of blanks by _ recording apparatus of the character disclosed in means of carbon paper or other transfer media, which highly satisfactory recording is obtainable thereby to produce multiple copies. with low levels of the signal currents, and in receiving blanks usually are carried by copyhold the frequency of its vibration are independent of the amplitude and frequency of the received marking currents. In the production of facsimile >copies the record 30 which the amplitude oi' swing of the stylus and ers such as rotatable cylinders or drums or other forms of platens that are scanned by the record ing apparatus during the reproducing operation, A further object is .a recording unit in which and these copyholders may be interchangeable 35 the power for driving the stylus is not derived in the apparatus so that they can readily be from the received signals, and in which the placed into` operative position in the recording amount of power applied to the vibrating stylus apparatus and can readily be removed therefrom may be maintained as high as desired and kept constant at all times during recording' operations. either manually or automatically. The record A further object is a percussion type recording ing operation is effected by means of a recording 40 stylus which is continuously vibrated at a high apparatus in which the movement of the stylus speed and intermittently contacts, or causes toward and from the record ysheet is positively marking impacts to be applied to, the record re controlled and limited at all times and in which ceiving sheet at intervals in accordance- with the the limits of this movement may accurately be transmitted subject matter, thereby to change or 45 adjusted and maintained. mark the surface of the sheet to record the sub Still another object is a percussion recording unit which may easily be adjusted with respect ject matter thereon in facsimile or otherwise. In recorders of the character heretofore ern to the record blank upon which it operates, and in which high »stability of adjustment of the ployed for producing records or facsimile stencils by means of a percussion recording stylus, the 50 recording unit and greater uniformity in results stylus generally has been energized or driven by are obtained. an electromagnet, the incoming electrical signals A still further object is a recording unit of the being applied to the magnet winding, the magnet character described which permits of greater tol being energized by the direct current components erances in the manufacture of the recording of the received signals. In such devices, however, 55 drums or other platens employed, and in which r 2,403,472 3 4 variation in uniformity of thickness of the stencils members have rollers 40, one of which is shown or other record receiving blanks. or irregularities in the stencil or other blank surfaces, do not dele~ in Fig. 6, that cooperate with the rear guide rail 23 to facilitate travel of the units 25 and 26 along teriously affect the record. The foregoing and other objects and advanu tages of the invention will be apparent from the following ,detailed description of the illustrative embodiments of the invention, taken in conjunc tion with the accompanying drawings, in which: the guide rails. The carriage member 3l of the recording unit is connected to the carriage mem ber 3B of the transmitting unit, as by a carriage link 42 firmly secured to portions 36a and 31a of these units, so that any movement of the record Fig. 1 is a view of a combined facsimile trans mitter and recording apparatus in which the re ing unit 2B longitudinally along the guide rods 10 22 and 23 will impart a similar movement to the transmitting unit 25, and vice versa. The various cording apparatus is constructed in accordance mechanical details for thus interconnecting the with the present invention; transmitting and recording units so as to cause Fig. 2 is a perspective view showing certain details of the recording device removed from its the line feeds thereof are disclosed in detail in scanning carriage; Fig. 3 is a fragmentarysectional view taken along the line 3-3 of Fig. 2, and including a them to operate in synchronism with respect to the aforesaid d’Humy et al. Patent No. 2,301,024, and for the sake of brevity certain of these de tails are not illustrated in the drawings herein. Power for operating the apparatus is supplied Fig. 4 is a fragmentary plan view showing cer 20 by a motor contained within a casing 4D, the motor preferably being of the synchronous alter tain details of the electromagnetic unit of the nating current type, although if desired may be device of Fig. 2, with its upper protective cover of the direct current type, it being understood removed: that the speed of the motor for any given opera Fig. 5 is a detail taken along the line 5-5 of 25 tion may be adjusted and maintained constant Fig. 3: by any of the various suitable means known in Fig. 6 is a view, in elevation, taken along the the art for this purpose. The power is applied by line l-l of Fig. 1; Fig. 'l is a perspective view of a modified form _ the motor through the medium of reducing gear mechanism in known manner, which gear nzech of the recording device; and Fig. 8 illustrates diagrammatically a circuit ar 30 anism is also contained within the casing 40, the motor and gear mechanism causing rotation of a rangement which may be employed with the recording drum for the device; transmitter and recording apparatus. Referring tothe drawings, and particularly to Fig. 1 thereof, a base 2l forms the principal sup port for the apparatus and the driving and con trol mechanism therefor, which base is adapted to rest upon an apparatus table or cabinet or driven shaft 4I which rotates the transmitting and recording drums 30 and 34 in the direction indicated by the arrow on drum 30 during the scanning operations. The gear mechanism also drives a line feed shaft 43 which has a threaded portion 43a that directly drives the recording unit 26, and through the medium of the carriage linke 42 also drives the transmitting unit 25 to other convenient support, and a cabinet prefer ably being employed so that certain of the power unit and amplifier devices used may be em 40 cause line feed scanning movement of the units with respect to the transmitting and recording bodied therein. drums 30 and 34. Secured to platesA 29a and 20h on the base 2l Preferably, and as disclosed in the aforesaid are brackets 2l in which are mounted a front d’Humy et al. patent, the apparatus is arranged track or guide rail 22 and a rear track or guide to accommodate transmitting and record receiv rail 23 which slidably support the longitudinally movable transmitting scanning assembly 25 and ing drums of different diameters in order to ac the recording scanning assembly 25. Preferably, commodate transmitting and recording blanks of the transmitting scanning -unit V2li comprises an different sizes, and for this reason the gear mech anism within the casing 40 is adapted to be shifted, as by the gear shift lever 42, in order to provide different driving speeds for the drums optical pickup system for deriving facsimile signals from an original blank 23 which carries the subject matter to be reproduced or duplicated. and therefore change at will the peripheral speed the blank being secured upon a cylindrical drum portion III of a copyholder which is indicated in of rotation of the drums 30 and 34. With the drum speed shift arrangement the linear scan its entirety by the reference numeral 3i. The copyholder 3| includes a cylindrical drum por 55 ning speed for the drums 3|! and 34 may be tion 34 adapted to support a record receiving changed if desired, or when drums of different blank 35 which is acted upon by the percussion diameters are used in place of the drums shown stylus 33 of the recording unit 2l. the number of revolutions per minute of the In general, any suitable means for scanning drums may be either reduced or increased to an the transmitting and record receiving blanks 60 extent such that the peripheral speed of rotation may be employed, for example, as disclosed in and hence the linear scanning speed will remain approximately the same irrespective of the size 4Patent No. 2,301,024, issued November 3, 1942, or of drums employed. Also, the driving ratio of in Patent No. 2,260,862, issued October 28, 1941. Also, any suitable type of transmitter may be em the gears which cause rotation of the line feed ployed for generating the facsimile signals sup 65 shaft 43 may be changed, as by a shift lever 45, plied to the recording unit, such of example as so that the speed of rotation of the feed screw illustrated in the foregoing patents and in Patent 43a and hence the number of scanning lines per inch may be varied. For example, when the shift No. 2,158,391, issued May 16, 1939, and Patent No. lever 45 is in its right hand position, as shown 2,176,442, issued October 17, 1939. The transmitting scanning assembly 25 and 70 in Fig. 1, the gear ratio may be such that the the recording assembly 2l are respectively transmitting and recording units scan at the rate mounted on traveling bases or carriage members of 100 lines per inch, and if the lever 45 is shifted to the left the gear ratio may be such that the `3l and 31, which latter members are each pro vided with guide blocks 38 and 33 slidably number of scanning lines may be increased to 120 mounted on a front guide rail 22. . 'I'he carriage lines per inch, the arrangement enabling the 5 number ci such as 'te „ aiming Eines per inch to be made he mest desirable results depend arcuate supports or saddles, the inner pair of these saddles preventing the cylinder 3| from dropping when it is released from the bearings 48 and .49 and the outer pair of saddles providing ing upon 'the subjectmatter and the kind of service for which it is used. If desired, and as described in detail in the a convenient rest for the cylinder 3| to enable aforesaid d‘Hurny et ai. patent, two line feed shaft the blanks to be applied to and removed >from the drums 30 and 34 at the beginning and termi members similar to vthe member 43, and which nation of a reproducing operation. may be caused to operate at different speeds re spectively, may be employed, one of which shafts As hereinbefore stated, any suitable transmit produces the line feed scanning movement of the 10 ting unit may be employed. In general, in an optical pickup system such a transmitting unit transmitter unit and the other of which produces the line feed scanning movement of the recorder employs a lens tube 66 containing lenses and an unit, whereby when transmitting and recording apertured plate aligned in position with respect drums of different diameters respectively are con to each other so that light from an exciter lamp is concentrated on a minute spot on the periph ery of the drum 30 and consequently on elemental currently employed, the reproduced record may be enlarged or reduced with respect to the subject matter _on the transmitting blank without caus 'areas successively of the subject matter sheet 29 ing distortion of the recorded subject matter. thereon during scanning. Another lens tube 61 The foregoing various features of variable speed contains lenses for directing the beam `of light of the transmitting and recording cylinders and 20 reflected from the elemental area of the record their respective line feed scanning means com prise subject matter claimed in the aforesaid d’Humy et al. patent, and for the sake of sim plicity such arrangements are not disclosed here sheet 29 at the time being scanned onto an aper-' ture and thence to a photocell, a light chopper in the form of a perforated disc being interposed between the photocell and the aperture in known in in detail. ’ 25 manner, the number of perforations or notches The cylinder 3| has reduced ends 46 and 41 in the disc and the speed `of rotation thereof de formed with internal tapered surfaces which re pending upon the desired rate of scanning, the frequency of the signal carrier current employed, ceive complementary bearing members 48 and 49. The bearing member 48 is secured to and driven and other factors. Preferably, and as disclosed by the shaft 4| hereinbefore referred to, and 30 in said Patents 2,158,391 and 2,176,442, the trans serves to drive the cylinder 3|. The member 49 mitter employs two light sensitive cells associated is secured to a shaft 5| journaled in ñxed upright with the light chopper disc or discs in such man bearing members 52 and 53 s0 as to be freely ner that the signals produced by the transmitter rotatable and also slidably movable longitudi need not be inverted before application to the nally within the bearings to permit entry and 35 recorder in order to provide a positive record withdrawal of the member 49 from the recessed from a positive original blank or a negative record portion of the end 41 of the cylinder 3|, and from a negative original blank, although if de thereby permit ready insertion and removal of sired one light sensitive cell may be employed and the cylinder 3|. and drums 30 and 34. ‘ . the signals inverted either in the transmitting or To facilitate the insertion and withdrawal of 40 recording circuits by means of a reversing switch the member 49, preferably there is provided a such as hereinafter described or by other suitable tapered cam member 55 ñxedly secured to the signal inverters of a type well known in the com bearing support 52, and coacting with this cam munication art. member is a second tapered cam member 56 which is secured, as by a set screw, to the shaft 5|. Secured to the cam member 56 is a handle The recording stylus actuating device, which is embodied within the recording assembly 26, is shown in detaily in Figs. 2 to 6 of the drawings, 51, and when the handle is raised upwardly as and is indicated in lts entirety by reference nu viewed in Fig. 1, this causes rotation of the cam meral 16. Referring particularly to Figs. 2 and 56 relative to the fixed cam 55, the adjacent . 3, the device comprises a circular ripple or flutter tapered camming surfaces of these members co cam 1| which during recording operations" is acting to cause the member 56 to .be shifted to continuously rotated at a constant speed by the right as viewed in the figure and thereby means of a motor 12, the cam being secured to cause longitudinal movement of the shaft _5| and the motor driving shaft by means 0f a collar 13 withdrawal of the bearing member 49 from the which is secured directly to the shaft in suitable recessed end 41 of the cylinder 3|, after which the manner, vas by a .set screw 14, the collar also cylinder may be slid to the right a distance suffi being secured to a plate 15 which in turn is cient to release the opposite end 46 from its asso secured to the ripple cam 1| in suitable manner, ciated drive member 48, A compression spring as by rivets or machine screws 16. When the 58 which loosely surrounds the outer end of the cam 1| is revolved by the motor 12 at a suitable shaft 5|, causes the member 56 to return to the 60 speed, a cam follower 1§ which has two camming working position when the handle is turned portions 19 is rapidly vibrated or oscillated to downwardly, the spring also causing the bearing wards and from. the surface of the sheet 35, Fig. member 49 to enter the end 41 of the cylinder 3, the cam follower being slidably mounted with thereby to insure that the cylinder is-properly in guideways in a casing 80. The casing 80 is supported during rotation thereof and to main 65 secured to a plate member 8| which in turn is tain a proper driving connection between the rigidly secured to the` housing of the motor 12. members 46 and 48. Instead of employing a cyl The stylus 33 is pivotally connected at 82 to inder 3| having the transmitting and recording the -forward portion of the carn follower.18 so drums formed or mounted thereon, separate that oscillation of the cam follower 18 by the rip transmitting and recording drums may be em ple cam 1| causes the point of the stylus 33 to ployed and maintained in proper driving relation oscillate rapidly in a direction towards and from in the manner disclosed in the aforesaid d’Humy the blank 35 to apply marking impacts to the et al. patent. blank in selected elemental areas thereof, the Fixed bracket members 66 and 6| are provided, stylus pivoting about the point 84. The rate of each of the bracket members comprising two 75 vibration or frequency. of the percussion stylus 2,403,472 7 l! may be varied within wide limits, depending upon the type of subject matter to lbe recorded and the degree of definition desired. When re cording facsimile signals, the speed of the motor 12 and the number of lobes or ripples on the ripple cam 1| preferably are su‘ch that the stylus will oscillate at a high frequency, for example, of the order of 1,800 cycles, thereby to produce exceedingly fine definition of the recorded sub ject matter. The lower end of the stylus 33 is pivotally serve to secure the portions 08 and B9 of the casing together, the screws also passing through eye portions in the phosphor-bronze spring mem bers 81 to secure these members in place. As seen more clearly in Fig. 2, the driving mo tor and electromagnetic unit are mounted on a plate 91 of non-magnetic material, for example, brass. The motor and electromagnetic unit are secured to the mounting plate in any suitable 10 manner, as by the machine screws 99 shown in Fig. 5, the mounting plate being secured to the traveling scanning carriage of the recording ap mounted at 3l to the upper end of an extension or leg 85 which is integral with and `projects up wardly from an amature 30 of the electromag netic control unit. In the illustrative embodi paratus, as shown in Fig. 6. Various types of polar and non-polar electro magnetic relay structures, different than that shown, may be employed to control the marking and non-marking positions of the stylus 33, which ment shown the armature 3l is pivotally mounted by means of two fiat, flexible, phosphor-bronze spring members 31 each of which is received at , relays may be controlled by received modulated one end within a side of the armature 36, as or varying signals applied directly thereto. in seen more clearly in Fig. 5, and are ?rmly se 20 stead of through signal repeating relays, although the polarized structure shown is preferred since it is sui’ilciently sensitive and fast in its operation to permit the faithful reproduction of facsimile signals at a high scanning speed. For example, with transmitting and recording drums having a circumference of the order of eight and one-half cured to the armature, as by brazing or in other suitable manner, The spring members 31 are secured at their other ends between the opposite halves 33 and 39 of a casing which surrounds an energizing coil 30 of a `polarized electromagnetic relay structure. 'I'he pole pieces 9| of the elec tromagnet preferably are composed of laminated strips, seen more clearly in Fig. 4, the laminated structure 3| in turn being supported between the inches and a drum speed of the order of one hundred eighty revolutions per minute, it is pos sible to obtain a linear scanning speed of approxi legs of a permanent horseshoe magnet 32. The 30 mately one thousand five hundred thirty inches .pole pieces are so arranged and the energizing , per minute, and thus the transmitting and record ing apparatus are adapted to operate at a suii‘i winding is in a direction such. that, when the ciently high speed as appreciably to reduce the coil Il is energized by current of a given polarity, time required for producing a stencil or other electromagnetic fields will be set up which causes wise recording a given piece of subject matter. rotation of the armature 00 about its axis 31 Fig. 6 shows various details of. the manner in which the recording unit 10 is mounted on the in one direction, and when the coil 9| is ener gized by current of opposite polarity, the arma ture 3l is rotated in the opposite direction. It will be noted from Fig. 3 that, when the armature Il and its extension 35 have been at recording scanning carriage 31, the base 31 of the unit being secured, as by screws |05, to a block 40 tracted to the position shown in the figure, this has moved the pivotal point 34 of the stylus to the right, in which position the stylus 33 has been rotated, in a counter-clockwise direction as viewed in the figure, to a position such that even though it is vibrated by the ripple cam 1| it does not contact the blank 35. If, however, the electromagnet is energized by a current of opposite polarity to attract the armature 30 and its extension 35 in the opposite direction, as 50 toward the left in Fig. 3, this will shift the pivotal point 34 of the stylus 33 to the left and, conse quently, will rotate the stylus 33 in a clockwise direction to a .position such that when vibrating it will engage the sheet 35 and mark the same. 55 In other words, when marking signals are re ceived by the electromagnetic unit, the armature 36 will be moved to a position such as to cause the stylus 33 rapidly to impact the sheet 35, and when spacing or non-marking signals are being 60 received the armature will be moved in the oppo site direction to shift the pivotal point Il so that the stylus 33 will not engage the blank 3l, thereby causing the stylus to delineate black and |06 that is slidably mounted within guide struc ture |01, the block |06 being internally threaded and receiving a threaded adjusting shaft |23. The recording unit is thereby made adjustable` towards and from the blank 35 to accommodate recording cylinders of different diameters, by means of the rotatable shaft |23, which is ro. tated by a knurled knob |23a to adjust the record ing unit to the desired positions, such as indi cated by the indicia A, B and C (Fig. 1) that appear on a plate member |22 secured to the carriage of the recording unit, the indicia re spectively corresponding to three different sizes of recording drums that may be employed. A graduated dial or Vernier |24 secured to the rod |23 enables a very accurate adjustment of the recording stylus 33 relative to the stencil or other blank. A pointer |25 carried by the plate mem ber 93 coacts with the plate |22 bearing the in dicia to indicate when the recording unit is ad justed for the size of drum to be employed. The method of thus adjusting the recording unit is described in detail in the aforesaid d’Humy et al. patent, „and for this reason it is not described in greater detail here. 'I'he line feed of the transmitting and record ing units is effected by means of a split block white, or marked and unmarked, elemental areas 05 on the blank which correspond with similar ele assembly comprising identical opposed split halves mental areas on the original blank from which |30, Fig. 6, which members are internally thread the signals were generated by .a transmitter such ed to receive the feed screw 43a, the members as the transmitting unit 23 shown in Fig. _1. As shown in Figs. 1 and 3, the limits of travel 70 being spring-pressed into engagement with the threads of the feed screws 43a by means of four ’ of the armature 36 may accurately be determined compression springs |3| which act between sup~ port members |32 and |33 and the upper and lower portions of the members |30. The mem by means of machine screws 35, Fig. 5, which also 75 bers |32 and |33 comprise the legs of a U-shaped by means of adjustable stop members 93 which are threaded into a U-shaped bracket member 3l secured to the upper cover Il of the unit, as 2,408,472 bracket which is secured to the recording scan ning carriage. Interposed between the inner sur faces of the opposite ends of members |30 are two wedge-shaped members |35, the lower mem ber |35 being secured to a split-nut release lever rock shaft |30, and the upper wedge-shaped member |35 being mounted on a rock shaft |31. When the handle |35a, Fig. 1, of the shaft |36 is rotated so as to turn the wedge-shaped mem bers |35 from the positions in which they are shown in Fig. 6, the split-nut halves |30 are 10 Referring to Fig. 8, there is shown a circuit arrangement suitable for interconnecting the transmitting and recording apparatus in accord ance with the present invention, although other known electrical systems suitable for transmitting and recording in facsimile may be employed, de pending upon the purpose for which the appara tus is to be used. At the transmitting end a scanning photoelectric cell 200 and a balancing l photoelectric cell 20| preferably are employed in the manner set forth in the aforesaid Patents forced to part a suiiicient distance to effect their release from the threaded rod 43a and thus enable both the transmitting and receiving units to be moved longitudinally to any position, such as their initial starting positions, after which the Nos. 2,158,391 and 2,176,442, and controlling the light applied to the cells is a light' chopper 202 which is rotated at alconstant predetermined shaft |38 is turned in a direction such that the light chopper preferably is of the order of 3300 speed by a motor in a manner well-known in the art. In the embodiment shown the speed of the wedge-shaped members |35 again assume their positions shown ln Fig. 6 and make the feed screw R.v P, M. so that the apertured portions thereof will produce a signal frequency of the order of 43a effective. . 20 2500 cycles. When light is falling on both photo In order that there may be no likelihood of cells, the signal amplitude is at a minimum due to' injury to the stencil or other blank by the stylus the balanced arrangement of the cells, and no sig 33 or injury to the point of the stylus when a nal is transmitted at this time. When a black recording operation has been completed, and par mark appears under the scanning ray, however, ticularly when the transmitting ‘and recording the two photocells become unbalanced relative to units are to be moved to their initial starting each other, and at this time there is transmitted a positions, a collar |4I, Fig. 6, is secured to the carrier frequency of 2500 cycles, which carrier is rock shaft |31, the collar carrying a pin |42 which modulated by the appearance or non-appearance is adapted to control a stylus retracting switch of a mark on the original copy. This modulat |44 that in turn controls the energizing circuit 30 ing frequency depends upon the speed at which of a solenoid |45, as explained in detail in the the white and black elimental areas pass by the d’Humy et al. patent. When the solenoid |45 is scanning light. For example, with an elemental energized, this causes retraction of its core |41. area of approximately eight circular mills where and effects withdrawal of the stylus a predeter the> scanning ray impinges on the subject matter mined distance from the recording drum when appearing on the transmitting blank, and a drum the solenoid |45 is energized, the limit of this of eight and one-half inches in circumference retractile movement being determined by the core and a speed of 180 R. P. M., the carrier frequency |41 striking a stop member |52 on the frame oi' will thus be modulated by a signal frequency of the solenoid when the stylus is in its proper re theforder of 1400 cycles. In the circuit of the tracted position. A dashpot |51 having a plung 40 balancing photocell is an adjustable impedance or er |58 received therein eases the impact of the resistance 204 which enables the photocells to be return of the recording unit to recording position accurately balanced with respect to each other so under the action of a retractile spring |0| when that each one puts out the same amplitude of the solenoid |45 is deenergized. signal. It will be understood thatthe phase rela The original copy sheet 29 is wrapped around 45 tionship between the two light beams for each of the transmitting drum 30, Fig. 1, preferably in these photocells will be so adjusted as to most such manner that the top of the copy is at the effectively balance when the scanning light is on left hand end of the drum when facing the ma the white background, as described in detail in chine, the right hand edge of the copy overlap the aforesaid patents. _ ping the left hand edge by a slight margin. The 50 The signal output >from the photocells is con copy may be held in position by any suitable nected to a thermionic preamplifier 203 of known means, such as elastic bands or garters |15, each type, and the transfer of signals from this ampli of which preferably comprises a helical spring fier to the succeeding similar amplifier stages is in the form »of an annulus, such as 'disclosed in controlled by a gain control device 205. Con Patent No. 2,255,868, or in Patent No. 2,301,024. 55 nected to the gain control device 205 is a second As shown in the figure, the leading garter mem amplifier 201 which preferably comprises two .ber is advanced axially along'the drum 30 from amplification stages. In both the preamplifier the left to right as scanning proceedsby a garter 203 and the amplifier 201 the constants of the pushing plate member |16 secured to the support circuits preferably are made such that the ampli , ing frame 36, and the trailing garter member is 60 fiers will not pass low disturbing frequencies advanced by a second pusher plate |11 on the caused by undesired pickup from interfering stray transmitting unit. The two elastic bands |15 are fields. All stages of the amplifiers preferably _are thus kept within a predetermined distance of of class A amplification whereby each of the each other and are kept immediately adjacent to has a constant average plate current the place where scanning is being effected, the 65 amplifiers output regardless of the amplitude of the marking bands rolling along on the copy sheet as the scan signal applied. ning proceeds and holding the copy sheet tightly The output of amplifier 201 is applied by means against the drum and preventing distortion in of a double pole switch 232 to the primary of a the optical scanning system which otherwise transformer 233. However, when the recorder isv might occur if the copy was not held tightly to be used for receiving signals from a remote against the drum. Two similar garter members 70 point over the line L, the switch 232 will be |15 are employed to hold the blank or stencil 35 thrown upwardly to connect the line L to the` on the recording drum 34, and usually these primary of the transformer 233. members may be placed adjacent to the ends of The secondary 234 of this transformer is con the blank 35, as indicated in Fig. 1. 75 nected to the grids 236 of a pair of similar elec 2,403,472 11 12 tronic devices 231, and the midpoint of the sec switch thrown to its lower position, the reverie operation will occur, and a positive original will ondary is `connected to a suitable source of nega be reproduced as a negative copy, or a negative tive biasing potential 238. The electronic tubes 281 preferably have a high amplification factor and a large mutual conductivity. The type 48 or the type 616 tube are examples of tubes suit able for the purpose. The anodes 238 of the tubes are connected to a relay 24| in series with a mil liammeter 242 and a resistance 243. The other end of the winding of relay 24| is connected to 10 original will be reproduced as a positive C091. ’I‘his enables the recorded copy to be reproduced in whichever form may be desirable. Other means known in the art for producing signal in version may, of course. be employed. 'I'he driving motor 12 for the stylus may be controlled locally by means o! a manually oper-v able switch 215, which either supplies or dis connects its supply current from the source 28|, or the recording apparatus may be operated by a source of positive potential whereby the relay will be energized when the tubes 231 are passing plate current in response to received signals. signals from a distant point transmitted over the The series circuit which includes the resistance 243 and the relay 24| is by-passed by a condenser 16 line L, as stated hereinbefore, and when this il done it may be desirable to also provide separate 244. control for the energizing circuit of the motor 12. 'I'he resistance 243 and condenser 244 operate For this purpose a distinctive signal, for example, to limit the maximum power input from the elec a steady tone of predetermined frequency, may tronic tubes 231 to prevent excessive current from be transmitted over the line L prior to a recording being applied to relay 24|. The resistance and operation, and this tone will be received by an condenser coact to cause the anode voltage on «amplifier 28| which is connected by conductors the electronic tubes 231 to drop to a low value 282 and 283 to the line switch 232. This tone will when a predetermined input level is reached, thus be selected by a filter or tuner 285, which may holding the anode current ‘constant for higher values. The current applied to the relay 24| 25 include amplifying and detecting stages and which causes energizing current to be applied to is, therefore, substantially uniform for the dura the winding 288 of a relay that controls through tion of a marking signal regardless of the signal its armatures 281 and 288 energizing current for level or intensity. It is also desirable that the the motor 12. The relay 288 upon operating also anode current change from the full steady state to zero be accomplished within a relatively small 30 closes a holding circuit for itself, through its armature 288 and make contact 288, and break input level change, The large amplification fac contact 282 and armature 29| of a relay 283, to a tor and the large value of mutual conductivity source of holding current 288. Relay 288 will, of the tubes 231 assist in obtaining this result, therefore, remain energized so long as it is desired the relatively high value of biasing voltage which is applied to the tubes assisting in effecting this 35 to transmit signals to the recording unit, and the motor 12 will be caused to run continuously dur result. ` ing this period. When the recording has been 'I'he repeating relay 24| selectively controls the completed, another distinctive tone or signal may application of energizing current from the source be transmitted over the line L, which tone will be 248 to the coil 88 of the electromagnet unit of the recorder. When the relay 24| is not energized, 40 selected by .a filter or tuner 294, which may in clude amplifying and detecting stages and which as shown in Fig. 8, current of a given character will supply energizing current to the relay 233. istic or polarity, for example, negative current, is Energization of this relay attracts its armature supplied from the source 249, through conductor 28 I , thereby breaking the holding circuit for relay 258, switch 25|, break contact 252 and armature 288 and stopping the motor 12. 253 of relay 24|, and conductor 254 to the ener 45 Various other control circuits for enabling op gized winding 88 of the electromagnetic relay eration of the recording unit over the line L may structure. thereby maintaining the stylus 33 out be employed such, for example, as various of the of engagement with the blank 85, notwithstand control circuits disclosed in the aforesaid Patent ing that the stylus may be oscillating by reason of rotation of the motor 12. In this position of the 50 2,280,862, or as disclosed in Patent 2,255,868, is stylus, white or unmarked areas are produced on the record blank 35. When the tubes 231 are passing plate current, sued September 16, 1941, and Patent 2,262,715, issued November 11, 1941. Other remote control circuits known in the art and suitable for con trolling the various functions of the recording in response to received marking signals, the relay apparatus from a distant point may be employed. 24| is energized, and through its armature 253, 55 Also, if desired, the control of the stylus actuat make contact 251, switch 25| and conductor 258 ing motor 12 may be associated with the control causes current of a different characteristic or op of the driving motor for the scanning mechanism posite polarity, for example, positive current, to shown in Fig. l so that, upon energization of the be supplied from the source 248 to the electro motor which drives the recording scanning unit. magnet winding 98, thereby actuating the arma 60 the motor 12 will simultaneously be energized. ture of the electromagnetic structure and rotating Where the signals for operating the recorder the stylus 33, in a counterclockwise direction as are received from an incoming line which may viewed in Fig. 8, to cause the vibrating stylus to represent a circuit originating in another city or impinge upon the surface of the blank 35 and different locality from that of the recording unit, produce black or marked elemental areas thereon. 65 it will be understood that the incoming signals The switch 25| is a reversing switch which en are suitably amplified prior to their application to ables the polarity of the current applied to the contacts 252 and 251 to be reversed, thereby pro viding for signal inversion whenever this is de-sirable. With the switch thrown to its upper po sition, shown in Fig. 8, a positive original copy at the transmitter will be reproduced on the stencil the amplifier stages shown, and that these sig nals may be amplified either at the place of origin, at the receiving end, or intermediate these points. 70 The photoelectric transmitter shown in Figs. 1 and 8 may be. balanced on a selected portion of the original blank 28 by closing a. switch 248, ` or other blank as a positive, and a negative orig Fig. 8, and manipulating the control 284 which inal will be reproduced as a negative copyI due is connected to the balancing photocell 28|, cor to the balanced photcell arrangement. With the 75 rect balance being indicated by a minimum de-` 2,403,472 14 i'lection of the milliammeter 242, The switch 245 is emplo ed because the electronic devices 231 are heavily iased negatively for class C operation, then set the unit 303 to the corresponding scale setting. In the event that the unit is not initially and if this bias is not reduced in some manner recording carriage unit will engage the carriage limit switch 3`|0 and automatically stop the driv ing motor and the transmitting and recording set or is improperly set, a rod 3|3 secured to the the small output from the photoelectric pickup device when it is nearly balanced may not be in dicated by the milliammeter 242. .A modification apparatus so that no injury can occur either to of the foregoing bala'ncing procedure is to direct the scanning apparatus or to the sheet or stencil the beam which isprojected into the photocell 200 by reason of overtravel of the scanning units. upon the lightest portion of the original which is 10 In order to prevent injury or shock to the trans to be' reproduced, Afor example, a pencil mark, and mitting and recording units when they are moved adjusting the amplifier control so that the stylus to their initial starting positions, either manually will >just mark the recording sheet 35. With this or automatically, there is provided a buffer in the setting anything lighter in shade than the portion form of a dashpct 3|4, Fig. 1, mounted on the of the original selectedfor the balancing opera frame structure 20a, the dashpot having a plunger tion will not cause energization of relay 24|, and 3|5 which is held in its extended position by a hence will not cause the stylus tomark the sheet. compression spring within the dashpot cylinder. The adjustment of the pickup by balancing it on When lthe transmitting and receiving carriages a selected portion of a given shade on the original are returned to _the left, a stop member on the in conjunction with the resistance and condenser 20 transmitting carriage engages the end of the pis combination illustrated provides a definite work ton 3|5, and as this movement of the units to ing range between light and heavy marks on the ward the left is continued the spring within the original which is desirable in'the case of “mark” dashpot 3|4 is compressed so that it prevents un and “no-mark” characteristics of a coated stencil due shock to the units, the structure also provid sheet on which recording may be effected, that is, 26 ing a suitable means for limiting the extent of a minimum threshold value of stylus marking ac movement of the umts toward the left and deter tion at any desired density of shade on the orig mining the desired initial starting position ofthe inal. units. ' In order to save operating time and cause the Other and additional control circuits and de scanning operation by the transmitter of the 30 vices for controlling the operation of the recorder, transmitter-recorder of Fig. 1 to stop approxi particularly whenit is connected to an incoming mately as soon as the subject matter on the origi line instead of to the transmitter as shown in Fig. nal blank 29 has been scanned, irrespective of the 8, and for maintaining a distant transmitter and length ofthe blank as measured longitudinally the local recorder in proper phase relation, may along the transmitting cylinder, a switch 300 is 35 of course be employed, various kinds of which provided. which switch may be mounted on the circuits and devices suitable for the purposeare traveling carriage of the recording unit '|0, the known in the facsimile recording art, for exam switch being connected, as by a flexible cord, in ple, as shown in Patents Nos. 2,260,862, 2,255,868, series- with a carriage limit switch 30|. Either of 2,262,715 and 2,301,024. ' the switches when operated tn open circuit posi 40 Fig. 7 of the drawings shows a modified form of tion will cause the driving motor and hence the the recording unit in which the stylus 33' is held scanning units to stop. Coacting with the switch against the teeth of a ripple cam 1|' by means of 300 is an actuating unit 302 therefor, which as a taut~ wire preferably composed of steel piano shown in Fig. 1 may `comprise a collar or.sleeve wire, the wire 350 acting as a return spring for member 303 that has a relatively close fit with 45 the stylus 33'. The stylus or hammer 33' is vi the guide rod 23 on which it is mounted, the mem brated at a high frequency by means of the cam ber 303 being slidable longitudinally along the '||' and a cam follower portion 35| formed on the guide rod and thus readily settable to different stylus. The wire 350 is maintained taut by means machine stopping positions corresponding to var ofv two studs 352 which are threaded into a bracket ious positions of the transmitter at the time the 50 member 353 and maintained in their adjusted po subject matter on the transmitting blank has sitions by lock nuts 354, >the studs 353 being ro been completely‘scanned. As shown, the adjust tatably adjustable lto give the desired tension to able unit 303 has a spring member 304 carried the wire 350. The bracket 353 may be ñrmly thereby, which spring member resillently engages mounted on the unit by means of the machine in a spline 305 in the guide rod 23, thereby to 55 screws or bolts 95’ which also serve as clamping prevent rotation of the unit about the guide rod members of the electromagnetic relay structure. and also to frlctionally engage the guide rod so that the unit will remain in any adjusted posi tion. The portion 302 of the unit 303 carries an The manner of controlling the marking and non .narking positions of the stylus 33' is essentially same as‘ that employed in connection with the adjustable switch-actuating pin 306 which is in eo the form shown in Figs. 2 to 5 hereinbefore referred the path of travel ofthe switch 300 and which ,0. operates to Open the normally closed contacts of Marking may be effected by the recorder upon the switch when the line feed movement of the /arious types of stencil sheets and printing plates transmitting carriage has caused the .latter to known in th'e art, including mimeograph, hecto completely scan the subject matter on the trans 65 graph and other forms of stencils, and plano mitting blank, thereby automatica-ily stopping the graphic aluminum or similar printing sheets. In transmitting and recording operations. the case of such printing plates or sheets it -will be The unit 303 is manually set by the operator understood that a transfer medium such as a prior to the scanning operation of any given sub sheet, ribbon or other carrier for a marking or ject matter, and to determine readily the setting image-forming substance is interposed between to which the unit should be placed there are pro the stylus and th'e printing sheet or plate. Also, vided corresponding calibrated scales 3|0 and 3|| records may be made upon the surface of one or whereby the operator may place the subject mat more sheets of paper or other record receiving ter sheet on the transmitting drum and visually sheets by means of carbon paper, ribbons or other discern the proper mark on the scales 3I0 and 75 transfer sheets in contact with the record receiv asoasva , y 15 ins sheets, the uncoated side of the carbon paper or other transfer sheet ordinarily being exposed to the action of the stylus, although for certain 16 and cam follower to vibrate said stylus at a prede termined rate, and means responsive to said re» ceived signals for causing the vibrating stylus selectively to be actuated into and out of mark purposes the carbon or other transfer sheet may be placed beneath the sheet or sheets on which ci ing position to produce a record corresponding to said received signals. the record is produced, thereby to mark the un- \ 4. Apparatus for recording on a record sheet. dei-side of the record sheets. comprising means including a recording stylus The invention has been illustrated and de for causing marking impacts to' be applied to said scribed in connection with facsimile recording apparatus, but it is to be understood that the 10 record sheet to mark the same in accordance with received marking and spacing signals represent recorder may be employed to record various types ative of the subject matter to be recorded, said of signals other than facsimile signals, for ex stylus being mounted so as to be alternatively ample, to produce charts, graphs or other records by signals generated in accordance-with various conditions to be recorded. Various other forms, movable into marking position and out of mark ing position with respect to the record sheet, me chanical driving means for vibrating said stylus modincations and uses will'suggest themselves in a direction towards and from the record sheet to those skilled in the art without departing from to cause the same to impinge upon the record the spirit of the invention, and therefore the in sheet with a predetermined constant pressure vention is not to be regarded as limited except as indicated by the scope of the appended claims. 20 which is independent of the signal level of the received marking signals, means responsive to I claim: said received marking and spacing signals for 1. Apparatus for recording on a record sheet, producing signals of different polarity respec comprising a platen for supporting- said sheet during recording operations, means including a tively corresponding to said marking and spac recording stylus for causing marking impacts in 25 ing signals, and means including an electromag termittently to be applied to said record sheet net responsive to said signals of different polarity to mark the same in accordance with' received y for causing the vibrating stylus selectively to be marking and spacing signals representative o1' actuated into and out of marking position to the subject matter to be recorded, said platen produce a record corresponding to said received and stylus being mounted so as to enable relative 30 marking and spacing signals. movement between them alternatively to position 5. Apparatus for recording on a record sheet, them into marking position and out of marking comprising means including a recording stylus position with respect vto the record sheet, me for causing marking impacts to be applied to said chanical driving means for vibrating said stylus record sheet to mark the same in accordance with in a direction towards and from the record sheet 35 received signals representative oi the subject to cause the same to impinge upon the record matter to be recorded, said stylus being pivotally sheet with a predetermined constant pressure mounted so as to be alternatively rotatable into which is independent of the signal level of the marking position and out of marking Position received marking signals, and means responsive with respect to the record sheet, mechanical driv to said received marking and spacing signals for 40 ing means for vibrating said stylus at a prede eilectlng said relative movement between the termined rate, and means including ari’~ electro platen and the oscillating stylus selectively to magnet and an associated armature responsive position at least one of them into and out of to said received signals for causing the amature marking position to produce a record correspond to move to one position when marking signals are ing to said received signals. ~ being received- and to another position when 2. Apparatus for recording on a record sheet, spacing signals are being received, said armature comprising means including a recording stylus providing said pivotal mounting for said stylus for causing marking impacts intermittently to and rotating the stylus selectively. be applied to said record sheet to mark the same 6. Apparatus for producing in facsimile on a in accordance with received signals representa 50 record sheet a copy of a picture, drawing, writing tive of the subject matter to be recorded, said or other subject matter, comprising a travelling stylus being mounted so as to be alternatively scanning carriage, a percussive recording stylus movable into marking position and out of mark mounted on said carriage for causing marking ing position with- respect to the record sheet, impacts intermittently to be applied to said rec means including a rotating cam having a plural ity of lobes thereon and a cam follower engaging ord sheet in accordance with received facsimile said lobes for mechanically vibrating said stylus riage for mechanically vibrating said recording at a predetermined rate, and means responsive stylus at a constant speed and at a constant am signals, means mounted on said travelling car to said received signals for causing the vibrating plitude irrespective of the amplitude of said sig stylus selectively to be actuated into and out of 00 nals, means including said carriage for causing marking position to produce a record correspond the vibrating stylus to scan the record sheet, and ing to said received signals. means responsive to received facsimile signals for 3. Apparatus for recording on a record sheet, causing the vibrating stylus selectively‘to be ac comprising means including a recording stylus tuated to a position for applying marking im for causing marking impacts intermittently to pacts tosaid record sheet and to a position to be applied to said record sheet to mark the same prevent the stylus from applying marking im in accordance with received signals representa pacts to the record sheet in accordance with said tive of the subject matter to be recorded, said received signals. stylus being mounted s0 as t0 be alternatively 7. Apparatus for producing in facsimile on a movable into marking position and out of mark record sheet a copy of a picture, drawing, writ ing or other subject matter, comprising a scan ing position with respect to the record sheet, a ning carriage, a percussive recording stylus rotatable flutter cam having a series of cam sur mounted on said carriage for causing marking faces thereon, a motor for rotating said cam at impacts intermittently to be applied to said rec a constant speed, a cam follower engaging said cam surfaces, means for causing said rotating cam 15 ord sheet in accordance with received facsimile 2,408,472 » 18 17 signals, means including motor driven cam mem bers mounted on said carriage for vibrating said recording stylus at a constant speé‘d and at a constant amplitude irrespective of the amplitude of said signals, means including said carriage for causing the vibrating stylus to scan the record sheet, and means responsive to received facsimile signals for causing the vibrating-stylus selectively to be actuated to a position for applying marking impacts to said record sheet and to a position to prevent the stylus from applying marking im pacts to the record sheet in accordance with said received signals. I - JAMES N. ANDERSON.