Патент USA US2108983код для вставки
Feb. 22, 193s. w. c;A H. FlNcH 2,108,983 TELEPICTURE SAYNCHRONI Z ING SYSTEM Filed May ll, 1936 4 Sheets-Sheet 1 SYNCHRONIZIN SIGNAL. GENERATOR TRANSMÍ‘ITER* î n--a RECEIVER ` AUDIO AND AMPLIF'lER RECTIFIER o__û „nu Feb. 22, 1938. W, G, HAF-,NCH ' 2,108,983 ` TELEPICTURE SYNCHRONIZING SYSTEM Filed May ll, 1936 4 Sheets-Sheet 3 « 54 ‘william W.WNmR. ATTORNEY. Feb; 22, 193s. w, G. Hf FINCH' 2,108,983 TELEPICTUR‘E SYNCHRONIZING SYSTEM Filed May 1l, 1936 l 4 Sheets-Sheet 4 9 r _ ‘ ' INVENTOR. wallzamrgîíbßì’nclz, Inf/¿wdr ATTORNEY. 2,108,983 Patented Feb. 22, 1938 UNITED STATES PATENT OFFICE 2,108,983 TELEPICTURE SYNCHRONIZING SYSTEM William G. H. Finch, New York, N. Y. Application May 11, 1936, Serial No. 78,993 (Cl. 178-695) ' ‘ 6 Claims. This invention relates to synchronizing sys- . of the worm changes the phase relation between tems, and more particularly relates to novel methods of and apparatus for maintaining a telepicture receiver in phase synchronism with 5 the transmitter. - Prior synchronizing systems comprised a fric tion clutch interposed'between the driving mo tor and the telepicture drum. synchronizing signals were used to disengage the friction clutch 10 until the receiver drum was in phase synchronism with the corresponding transmitter drum and then re-engage the clutch so that the receiver drum would continue to rotate in> proper phase synchronism. However, a friction clutch could l5 not maintain accurate phasing of the apparatus since slight slippage inherent in the friction the motor and the drum- without interrupting ythe positive driving connection therebetween. The worm is turned when the drum is out of phase synchronism 'with respect to the trans- 5 mitter drum under the control of cyclic syn chronizing signals. Normal interlocking of the Worm Wheel with the. worm gear permits nor mal rotation of the telepicture drum. However, when the'worm wheel is turned, a phase co-r- 10 recting motion is superimposed upon the normal rotation of the worm gear connected to the drum. In a preferred arrangement, the worm wheel moves the worm gear in a direction opposite to the normal rotation thereof. The superposition 15 of the two opposite‘rotative effects produces a resultant rotation of the drum. Since the posi clutch, and intensified by wearing thereof, could not positively predetermine phase synchronous tive driving relation between the motor and the drum is' maintained during angular correction, positions. ` ` ‘ In my Reissue Patent No. 19,575, I disclose a 20 positive driving connection between the scanner and the motor. The positive driving connection includes a pawl and ratchet wheel which are normally engaged to maintain'the scanner in 2, operation. When the scanner is out of phase, the positive driving connection is disconnected at the pawl and ratchet wheel until the scanner is in proper position. A cyclic synchronizing signal reengages the pawl and ratchet to continue 30 the synchronous operation- of the scanner. In my co-pending application Serial No. 65,869, filed'Feb. 26, 1936, I disclose a positive or over-. running clutch in the positive driving connection between the motor and the telepicture drum. l) The receiver drum is rotated at a slighly faster rate thanthe corresponding transmitter drum. The overrunning clutch is disengaged at a pre determined angular position of the drum until the synchronizing signal reengages it. The syn chronizing signal is transmitted during the cor 40 responding angular position of the transmitter my invention may be termed a controlled slip 20 driving mechanism. The slip, or relative angular change between the motor and the drum is di rectly controlled by rotation of the worm wheel normally interlocking with the wormv gear. In a preferred embodiment of my invention, the worm wheel superimposes a speed of rotation upon the drum equal to its normal speed of ro tation but in the opposite direction or sense thereto. 'I‘he resultant is an effective stand still or'interruption of rotation of the telepicture 3 drum without the use of a friction brake, clutch or the like. The drum is subjected to the con trolled slip angular correction if it reaches a pre determined position in its rotation cycle beforeA the synchronizing signal is received. 'I'he effect 35 of the controlled s_lip is to maintain the drum ' at this _predetermined position until the syn chronizing signal is received without interrupt. ing the positive driving connection between the drum and the motor. The synchronizing signal .40 interrupts the controlled slip of the drum to co-n drum so that both drums are maintained in ac tinue its rotation in accurate phase synchronous ` curate phase synchronous relation. In accordance with my present invention, I relation with the transmitter drum. Itis accordingly an object of my present in vention to provide novel methods of and means 45 for maintaining remote electro-mechanical sys contemplate a positive driving connection be-v tween the motor and telepicture drum with means for changing the relative phase relation between the motor and the drum without interrupting the positive drive connection. »0 The motor drives the telepicture drum through a worm and worm gear arrangement which nor mally interlock to 'v transmit the rotative power in a positive driving'r'elation. Means are pro vided for rotating the worm when the receiver 55 drum is out of phase synchronism. 'I'he rotation tems in synchronous relation. . ’ » Another object of my invention is to provide novel methods of and apparatus for maintaining w a telepicture receiver in phase synchronism with its transmitter. It is still another object of my invention to provide novel methods of and means for effecting stand-still of a driven member while maintaining u 2 2,10S,9@3 on photoelectric cell it produces corresponding a positive driving connection with its source of motive power. electrical signals which are-ampliñed by ampli ’ fier 22. A light “chopper” or an audio frequency carrier wave may be employed with the amplifier 22 to facilitate transmission of the varying uni directional picture signals as is well known in A further object of my invention is to provide novel methods of and means for changing the Ul relative angular position of a rotating member without interrupting its positive drive connection to the driving member. It is still a further object of my invention to j provide a novel synchronizing system whereby the translating member at a remote station is main tained in phase synchronous relation with the corresponding member at a transmitter station by controlling its angular position with cyclic syn chronizing signals without the interruption of a - . The telepicture signals may be directly trans mitted to a remote station overl wire lines or may be transmitted by radio transmission _ means. 10 Figure 1 illustrates a transmitter 23 connected to the output of ampliñer 22 for converting the audio frequency telepicture signals into corre sponding radio frequency signals which are radi 15 positive driving connection to the source of nio-= tive power for the translating member. ated by antenna 2d. These and other objects of my invention will become evident in the following description taken for effecting synchronization of the transmitter picture transmitter. . picture receiver. Figure 3 is a pian view of a preferred embodi 25 ment of ' a telepicture receiver embodying the novel phasing mechanism. Figure 4 is a longitudinal sectional View taken along 4_8 of Figure 3. Figure 5 is the cross-sectional view taken along 30 5-5 of Figure 4, illustrating the operation of the phasing mechanism oi’ my present invention. Figure 6-is a modification of my invention cor . Figure 7 is a longitudinal cross-sectional view of ~ a further modification of my present inven tion. scanning apparatus in a manner to be described in detail. The synchronizing signals are prefer ably transmitted once per scanning operating. 20 Figure 2 is a schematic illustration of a tele responding to Figure 5. l synchronizing signals are cyclically transmitted in connection with the drawings, in which: 20 Figure 1 is a schematic illustration of a tele ' Figures 8 and 9 are sectional views taken along 8-8 and 9-9 of Figure 5 respectively showing details of the synchronizing apparatus. 40 the art. Figure 10 is an end view of the embodiment corresponding to Figure 7 illustrating the syn chronizing mechanism control. The schematic diagrams Figures 1 and 2, of a telepicture transmitter and receiver respectively, are described to more clearly set forth the func tion and relation of the synchronizing mecha nism of my present invention. It is to be under When a drum is used as in the preferred em bodiment, the "underlap” period of the rotation cycle is employed to transmit the synchronizing signal. The underlap period corresponds to the portion of the picture drum where the opposite 25 ends of the picture i3 are gripped or otherwise fastened into position on the drum. In a con tinuous sheet system, the synchronizing signal is transmitted during the return oscillation movement, marking the beginning and end of 30 each scanning line excursion. The transmission of a synchronizing signal for a continuous sheet system is described in my Reissue Patent No. 19,575. A cam 25 is mounted upon the shaft 26 of the 35 telepicture drum lll. A projection 2l of the cam 25 is positioned angularly corresponding to the underlap portion of the drum M. The edge 28 of the picture sheet i3 determines one side of the underlap zone and is gripped by clamping means 40 internal to the drum I4 in a manner preferably as described in. my co-pending application Serial No. 72,990, filed April 6, 1936. The synchronizing cam switch 30 is cyclically g closed by the cam projection 21 to impress suit 45 able synchronizing impulses upon the ampliiier 22 from the synchronizing signal generator 3i. stood that the telepicture system and circuits ` synchronizing switch 30 is connected in series described are by example only and that the syn 50 chronizing mechanism to be hereinafter described in detail is applicable to other telepicture or fac simile systems. Referring to Figure 1, a source of light I0 generates a beam I I focused to a point by a lens system I2 upon the picture I3 to be transmitted, which is mounted on the cylindrical drum I4. Ii’ the picture is scanned one hundred lines per inch, the diameterof the light spot focused upon the picture I3 vshould be .01 inch. The retracted 60 beam I5 from the .picture is focused upon the photoelectric cell I6 by lens system I'I. The in tensity of the refracted beam I5 is proportional to the shading of the picture elements which are with the synchronizing signal generator 3l output to a suitable portion of the telepicture amplifier 50 22 schematically indicated in Figure 1. 'I‘he syn chronizing impulse effective during the underlap period is preferably of intensity somewhat greater than the maximum or “white” telepicture signal intensity in order to readily distinguish the syn 55 chronizing signals from the telepicture signals at the receiver. Á ' The synchronizing signal generator 3 I may be a direct current source which produces a uni directional impulse at each closure of cam switch 60 30 or may be an audio carrier frequency signal which is unmodulated during the synchronizing period and is suitably modulated by the picture signals during the remaining period of the cycle. successively moved past the light beam II. The picture drum I3 is rotated by worm I8 and ' A preferred embodiment of such a method for 65 worm gear I9 which suitably reduce the speed signal generation forms the basis of my co-pend of the motor 20. Motor 2U is preferably a syn chronous motor connected to/a commercial elec trical supply line 2I, for example a sixty cycle, 70 110 volt system. 'I'he drum may be driven at a normal speed of 100 revolutions per minute which, with one hundred lines scanned per inch, results in one inch of the picture traversed per minute. 75 The retracted picture light beam l5 impinging ing application Ser. No. 74,419. . Figure 2 is a schematic diagram of a telepic ture receiver used in conjunction with the trans mitter of Figure l. and employing the synchroniz 70 ing mechanism of my present invention. A radio receiver and rectifier 32 is connected to a receiv ing antenna 33 for receiving the radio trans mitted signals from the radio transmitter 23. If a wire line is used, suitable amplifying and line 75 3 arcanes equipment are instead employed. The ’output of the receiver and rectifier 32 are connectedto an audio amplifier 3d. The output of audio amplifier 34 is coupled to a class B push-pull out put stage 35-36 by an inter-stage coupling transformer 31. The output of the push-pull stage 35-36 is connected tothe primary 38 of the output transformer 39. The output of the secondary 45 of transformer 3S is connected to a photolamp 5I containing a gas such as neon, for producing a light beam 62 output in accord ance with the telepicture signals received. The light output «32 from lamp 5I is suitably focused upon the record sheet 49 on the receiving drum 55 by a lens system 42’. . I prefer to use a neon crater photo-lamp di having a control electrode ¿43 which is connected to one terminal 45 of the transformer secondary LIU, and an auxiliary or striking electrode 45. The crater plate Q6 of lamp 5I is connected to the positive terminal of a suitable direct current source 51, the negative terminal of which is con nected to ground. The other terminal ¿i8 of the transformer secondary di) is connected to the crater plate 46 through a variable resistance 5I. The auxiliary or striking electrode 45 is con nected to ground by lead 52. As is Well known in the art, the auxiliary electrode 45 maintains a striking or discharge condition at the photo lamp crater plate 66, so that it will always be in readiness to respond to telepicture signals intro duced between the plate 56 and the control grid ¿33. A by-pass condenser 53 is connected between the output terminal 48 and ground. The receiver drum 55 is driven by a syn chronous motor 56 connected to supply lines 2l'. The lines 2 I ’ are preferably from the same alter nating current supply lines 2| as those of the transmitter although such condition is not essen tial. The synchronous motor 5t drives drum 5@ through the schematically indicated synchroniz ing phase adjusting mechanism 55. The phase synchronizing or angular drum adjusting mech anism 55 is described in detail hereinafter. The drum phasing mechanism 55 maintains a posi tive driving connection between the shaft 55 which is driven positively from the motor shaft 51 through worm 58 and worm gear 59, and the shaft 6B directly attached to the receiver drum 5i?. ' ' A control plate 5I cooperating with the phas ing mechanism 55 is actuated by the synchroniz ing magnet 62 through its armature 63. Drum 50 is preferably driven at a slightly faster speed 55 than the corresponding transmitter drum I6, for example in a ratio of 101:100. The phasing mechanism 55 is under the con trol of the synchronizing magnet 62 to maintain the drum 50 in phase synchronism with the 60 transmitter drum I ê as will be hereinafter set ñows to the push-pull amplifier stage 35-36 dur ing the reception of the telepicture signals. The cam switch ‘l5-_1I is opened by the pro jection 13 of the cam 12 during the synchroniz ing or underlap period of the receiver. The CT! anode current from source 61 is accordingly di rected to the ampliñer 35-36 through the syn chronizing relay 15, which relay 15 is otherwise short-circuited by switch 1li-1I. The synchronizing signal, as hereinabove de 10 scribed, occurs during the underlap period of the. picture transmitter, and is preferably of greater magnitude than the telepicture signals. Syn chronizing relay 15 is preferably a marginal relay responding only to the increased magnitude sig nals so as to avoid the possibility of interference of the synchronizing action by any of the tele picture signals. The push-pull ampliñer 35-36 rectifles an alternating current synchronizing impulse in the anode lead if such is used, and 20 the actuation of the relay 15 is by rectified or unidirectional current as will be understood by those skilled in the art. Although I prefer to use synchronizing signals of increased intensity, and a marginal synchro 25 nizing relay, I have also successfully employed synchronizing signals of intensity equal to the maximum intensity picture signals to operate an ordinary relay. It is also to be understood that the synchronizing magnet 62 may be directly en 30 ergized by the synchronizing signals, displacin the relay 15. ' The receiver drum 5i) is prepared for the syn chronizing signal during its underlap period by cam 12. 'I‘he synchronizing signal will flow through tol energizeV the synchronizing relay 15 which then closes the relay contacts 55-(56, locally energizing the synchronizing magnet 62. The synchronizing magnet 52, when energized, will attract the armature 63 away from control 40 plate 6I to permit the phasing mechanism 55 to continue to normally drive the receiver drum 50; i. e., if the drum 50 were in phase synchronism and in proper phase, the release of armature 63 away from the plate 6I would avoid phasing or 45 angular correction by the mechanism 55. The control plate 5I »of the phase correcting mechanism 55 has a notch 16 cn its periphery; the angular position of notch 16 corresponds to the angular position of the underlap zone 1d of 50 drum 5G and that of the projection 13 of cam 12. The armature 63 is normally mechanically biased by spring 11 against the periphery of the control plate 6I. Armature 63 accordingly engages the notch 15 of control plate 6I and holds it against 55 rotation. By preventing the rotation of control plate 5I, the angular or phase correcting mecha nism 55 is actuated to effect >the phase synchro vnism of drum 50 with transmitter drum I4 in a manner to be described in detail hereinafter. 60 The anode potential source61 for the push pull amplifier stage 35-36 is supplied to the center tap 68 of the primary 38 through the syn By rotating drum 5G at a slightly faster rate than the transmitter drum I4, for example in the ratio of 101:100, the underlap period of the drum 5@ will reach the predetermined position corresponding to the engagement of armature 63 65 of notch 15 slightly before the normal reception of the synchronizing signal from the transmitter. chronizing cam switch 1li-1I. A cam 12 is con The cam 12 will accordingdy open cam switch forth. A‘direct current potential source 6d sup plies the synchronizing magnet 52 through its relay contacts 65-65. ß. nected to the shaft 60 adjacent the drum 50. 1li-1I by the projection 13 and permit the ener The projection 'I3 of the cam 12 is in the same 70 angular position on shaft 60 as the underlap or “dead” zone 14 of the drum 50. The cam switch gization of synchronizing relay 15 by lthe syn 1li-1I is normally maintained closed during the ymajor-portion of the rotation of cam 12, and the 75 anode current from source 61 normally directly chronizing impulse as it is received. The ener gization of synchronizing relay 15 by the syn chronizing impulse will close relay> 65-156 to correspondingly energize the synchronizing mag net 62 to attract the armature 63 away from en 70 4 2,108,983 gagement with notch 16 of control plate 6i. The positive driving connection between the motor 54 and the drum 56 is continuously maintained and the synchronizing signal in attracting the armature 63 from the control plate 6| permits the drum 99 to continue rotating with the posi 10 worm gear 91 and shaft 60 to the drum 59. Worm 96 does not rotate during its normal interlocking with worm gear 91. The control plate 6|, free to rotate on shaft 60, is freely turned thereon due to the interlocking of the skew bevel gears |90 and itil. ` ' tive driving connection intact and in accurate phase synchronous relation with the transmitter The armature 63 is normally biased by spring 11 against the periphery of control plate 6I. drum. When armature 63 engages with notch 16 the normal rotation (indicated counterclockwise) of~ 10 Figure 3 is a plan view of a preferred embodi-I ment of a telepicture receiver utilizing the phas control plate 6| is arrested. ing or angular correcting mechanism 55 herein above described. The apparatus is mounted mally biased against control plate 6| by spring A pawl |03 is nor G99 to co-act with a notch |95 on control plate 6l at the instant armature 63 engages notch 16 in order to prevent rebound of the control plate 15 6l to insure immediate stoppage thereof. When control plate 6| is stopped from its free drives a reduction gear train 8i to rotate, at a ~ predetermined reduced ratio, the spur gear 92 rotation on shaft 69, pinion |9| is moved relative » to the stationary teeth of the skew bevel gear |60 which is connected to one end of the worm or 20 scanner feed screw 83. The worm 93 is connected since the interlocking action of worm 96 and to the carriage 84 containing the electrooptical worm gear 91 forces it to execute this relative scanning mechanism electrically connected to motion. The relative movement of the pinion iti on skew gear H99 causes pinion Ill! to rotate. the receiver equipment by cable 85. Carriage 99 is moved parallel' to the wis of drum 59 along Since worm shaft 95 is originally attached to pinion itil, the worm 96 will correspondingly 25 tracks ‘t6-81' guiding rollers 88 of carriage 99. Details of the scanning arrangement are described rotate therewith. Rotation of 'pinion |9| as in my co-pending application Serial No. 65,869 illustrated in Figure 5, will be clockwise as indi cated by the arrow on the dotted position there referred to above. ‘ The focusing system 42’ for the recording light' of. The dotted position of pinion lill and worm 30 beam 42 corresponds to the optical recording sys 96 corresponds to the continued rotation of the 30 tem described in connection with Figure 2 to worm 96 and pinion |91! from the solid position.A translate the receiving telepicture .signals upon Clockwise rotation of worm 96 is _designed to the sensitive recording sheet 49 fastened on drum superimpose upon worm gear 91 a motion oppo upon a cast iron base 18. The motor 59 drives drum 59 through the mechanism 55 by worm 58. A pinion 99 connected to the end of shaft 69 50. The record sheet 49 is attached to the drum 50 by internal clamping mechanism such as dis closed in my application Serial No. 72,990, filed 40 site to its normal rotation.. Accordingly, since the normal rotation of worm gear 9i and its shaft 69 is counterclockwise, the April 6, 1936, operated by levers 99. Roller 9| is superimposed rotation by worm 96 is made clock pressed upon drum 59 to facilitate mounting of the record sheet 49 thereon by continuously wise. smoothly pressing against the sheet. Figure 4 is the cross sectional View taken along él--fl of Figure 3 through the phase cor recting mechanism 55. The shaft 5t of motor 54 drives worm 58 which rotates worm gear 59 The phasing or angular correction of the synchronizing mechanism of my present inven- „ tion superimposes upon the normal rotation of 40 the driven member a counter-rotationv while maintaining a positive driving connection to the driven member. The ratio and proportions of the skew gears £99 and i0! and worm 96 and 45 keyed to shaft 56 which is journalled in bracket worm gear 91 are preferably chosen so that when 45 92. A sleeve 93 is keyed to the end of shaft 56. A bracket 99 extends from sleeve 93 to rotatably support shaft 95 of worm wheel 96. Worm 96 coacts with worm gear 91 which in turn is keyed 50 to one end of shaft 60. Shaft 69 is journalled in bracket 98 and also in bracket 99 at the opposite end of drum 59. Drum 59 is also keyed to the sla;v 69. The synchronizing cam 12 is attached to the hub of drum 59. The synchronizing switch 55 't0-1i is attached to the top of bracket 99 to coact with the cam' 12. The worm Wheel 96 and worm gear 91 normally the rotation of stop plate 6i isi arrested, the counter-rotation superimposed upon driven shaft @il is equal to the normal speed of rotation there of but in the opposite direction. An effective stand-still of the shaft 60 is effected by the 50 mechanism 55. - ‘ . Although in my preferred embodiment a coun ter-rotation at a rate equal to the normal rotation is used to effect the phasing or angular correction . I interlock to transmit the rotary motion of shaft of the drum 59 with respect to the transmitter 5,5 drum in response to synchronizing signals, it is to be understood that it is by-way of example and not limitation. The principle of my present in 56 to shaft 69 inl a one-to-one or continuous 60 manner. Figure 5 illustrates the interlocking of worm 96 and worm gear 91. The control plate vention is also applicable to systems employing intermediate speeds of superimposed correction 60 movement either in the counter-direction to the 6| is loosely mounted upon shaft 60 between worm gear 91 and bracket 98. A skew bevel gear |99 is integral with control plate 6| and coacts with a skew bevel pinion I 0| attached to one end of the shaft 95 of worm 96.1 A housing §92 is at tached to the outer edge of the control plate 6|. The normal interlocking of worm 96 and worm gear- 91 causes the control plate 6I to‘rotate in 70 correspondence with the normal rotation of shafts normal rotation or in the normal direction of rotation.J When control plate 6| is stopped by the arma 56 and 60, through the normal interlocking of skew bevel gear |00 and its co-acting pinion |0i. A positive driving connection is effected from mo tor shaft 51 through worm 58, worm gear 59,y 75 shaft 60, sleeve 93, worm 96 interlocking with ture 63, normally mechanically biased toward it, the shaft 69 of the drum 50 is affected by the action of the phasing mechanism 55. Since the receiver drum is preferably normally rotated at a slightly faster rate than the transmitter drum, armature 63 will engage notch 16 of control plate 70 6| `lust before the incoming synchronizing signal causes the energization of the synchronizing mag net 62. when synchronizing magnet 62 is en ergized by the synchronizing signal,‘the engage ment of the control plate 6| with armature 6_3 75 2,108,983 is released, permitting the drum 50 to continue rotating in phase synchronous relation with the transmitter drum. " The synchronizing signal being transmitted during the underlap period as _described in con nection with Figure 1 marks the corresponding underlap position of the receiver drum which in turn corresponds to the position of notch 'i6 on control plate 6|. ' Figure 6 is a modification of the embodiment as illustrated in Figure 5 by employing two opposed worm wheels 96 and 96' coacting with the worm gear 91 upon a common bracket 94'. The corre sponding skew bevel pinions |0| and |0|’ coact 15 with the common skew bevel gear |00 integral with control plate 6|. The action, of _the two op posed worm Wheels 96--96' together with their corresponding pinions |00 and |0| is additive in that they impose a common direction of motion 20 upon worm gear 9`| when angular correction is eiîected. The opposed worm and pinion arrange ment is preferable from the standpoint of dynamic balancing about the axis of rotation. The con trol plate 6| and skew bevel gear- |00, integral 25 therewith, is~preferably made of a light weight al loy to minimize the eiîect' of residual inertia in the ' operation of the control mechanism for the phase adjusting device 55. , Figure 7 is a longitudinal cross-sectional view 30 through another embodiment of the angular cor recting me nism 55’ corresponding to the mech anism 55 d scribed hereinabove. Shaft 5l' con nected to a suitable motor, drives worm 58’ which engages with worm gear 59'. The worm gear 59' 35 is keyed to sleeve 56’ concentric with control shaft H0. Sleeve 56’ is journalled in bearing ||| extending from the housing ||2 of mechanism 55' and integral with housing H3 enclosing worm 40 gear 59’ and worm 57?.. Bracket member Hd extends from sleeve 50' and rotatably supports shaft H5 of worm wheel | i6. Worm | I6 meshes with worm gear | il which is keyed to shaft 60'. The telepicture drum 90 is keyed to shaft 60’ to rotate therewith. Sleeve 45 | |8 is concentric with shaft 60' and is journalied in bearing |20 extending from housing | i2. Sleeve Hi8 is integral with the bracket member ||é| and supports the right end thereof. A positive 'driving connection is maintained from the shaft 5l' of the motor to the telepicture drum 50 as follows: Worm 58', worm gear 59', > 5 control plate 6|’to the bevel gear |20. A bevel ` gear |2| supported on rod |22 journalled in brack et member Hd meshes with the bevel gear |20. A spur gear |23 is external to the bracket member H0. Gear |23 meshes with gear |24 which is connected to the shaft | l5 which supports the Worm H6. Figure 9 is the sectional view taken through Figure 7 along 9_9 and further illus trates the intermeshing gears connecting the con trol plate 0|' to the worm || 6. ' ' parted to bracket member iM to the worm gear ||`| to effect a- link in the positive driving con nection between the motor and the picture drum 15 50. Worm H6 does not normally rotate with its shaft H5 and is carried in a path concentric with the worm gear ||l with which it interlocks as bracket member ||Q rotates. The spur gears |23 and |20 accordingly do not normally rotate but 20 are also carried in a circular path as is the worm HS. The bevel gears |20 and |2| normally mesh but do not move with respect to each other in a similar manner. Since bevel gears |20 and |2| do not normally rotate with respect to each other 25 „ and since bevel gear |2| is moved in a path con centric to the axis of bevel gear |20, the gear |20 will be forced to rotate while intermeshing with gear |2|. Control plate 6|' being connected to bevel gear |20 by‘rod ||0 accordingly normally 30 rotates during the rotation of the drum 50. - It is to be understood that during the normal operation of the drum 50 from the motor shaft 5l', a positive driving connection is maintained therebetween, that worm H6 does not rotate on 35 its axis but is carried in a path concentric to the axis of the drum shaft 60’ and that bevel gear |2| also does not rotate on its axis but forces bevel gear |20 to rotate to correspondingly re Volve control plate 0|'. The normal rotation of 40 rod i i0 by the intermeshing gearing system of~ mechanism 55’ is at the same speed and direction as the rotation of sleeve 56’ encircling the rod H0. The rod H0 accordingly revolves together with the sleeve 56' with zero relative speed there between. ' Figure l0 is an end view of the apparatus illus trated in Figure '7 showing the arrangement of the control plate 6|', the synchronizing magnet 62 and the armature t3 coacting with a notch 50 'I6' in the control plate periphery. Spring 'il' normally mechanically biases armature 69 to ward the control disk 6|'. Pawl |03' coacts with locking of worm ||6 with worm gear H7 corre its notch 'i6' is arrested by armature 63. bodiment illustrated in Figures 4 to 6. - The phasing or angular adjusting means of drum 50 with respect to the motor shaft 5l' is eñected by rotating worm ||6 to superimpose a counter-rotation upon gear lil. The control .plate 6|' is situated external to the mechanism 55’ and is connected thereto by the shaft ||0 which is free to rotate relative to sleeve 5S'. The control plate 0| ' is affected by the synchronizing magnet 62 and the synchronizing signals in a manner similar to the hereinabove described con trol plate Si. However, in the embodiment de scribed in connection with Figures '7 to 10, the control plate is external to the mechanism 55' and is connected to the phasing worm wheel H6 by a series of gearing connections in the follow ing manner: Referring to Figure 8, the rod || 0 rotatably supported within sleeve 56’ directly connects the 45 fi sleeve 60', bracket member ||l|, worm H6 sup ported by bracket I It and interlocking with worm. gear H1 which is keyed to shaft 60'. The inter sponds to the similar portion of the previous em 10 Worm H6 normally interlocking with Worm gear ||î transmits the- motive power directly im plate 6|’ to prevent rebound of the plate when ` 55 A counter-weight |25 is preferably cast integral with bracket member | i0 to dynamically balance the gearing mechanism connected to the opposite side of the> bracket member Hd. ll‘he operation of the phasing or angular cor 60 rection mechanism 55' is similar to that de scribed hereinabove in connection with the modi ilcation illustrated in Figures 4 to 6. ’I‘he drum 50 is driven by the motor through the motor shaft 5l' by the~positive driving connection in 65 cluding the worm 58’ and Worm gear 59' which motivates the synchronizing mechanism 55'. The drum 50 is preferably driven at a slightly faster rate""than the corresponding transmitter drum - so as to insure the engagement of notch 16’ 70 of control disk 6|' with armature 03. When the rotation of control disk 6|' is arrested, the rotation ofbevel gear |20 is prevented. Since bevel gear |2| is turned in a concentric path about the axis of rotation of the drum 50, the 75 aioaees 6 controlling the rotation of said driven shaft with out destroying said continuous mechanical inter connection whereby the angular position of said and |24 to turn the shaft ||5 of Worm wheel IE6. driven shaft is alterable with respect to said driv ing shaft; and a synchronizing magnet responsive The rotation of worm wheel ||6 superimposes a to cyclic synchronizing signals for arresting the counter-rotation upon worm gear ||1 to eifect . the angular correction by the mechanism 55’. rotation of said mechanism in the event said The ratio and proportions of the respective driven shaft is not in synchronism until rsaid gearing in the phasing device 55' is designed so driven shaft is in synchronous position, once per that by arresting the normal rotation of gear revolution of said driven shaft. 3. In a synchronizing system, a driven shaft; a _|20 the worm ||6 is turned lat a rate and in the direction to impose a counter-rotation _upon gear driving shaft; a driving connection including gear ing from said driving shaft to said driven shaft; ||'| at a rate which is equal to its normal rota tion. The drum 50 will be effectively stopped a stop-plate -mechanically connected to and nor mally rotated with said driving connection for 15 from rotation and held in the stop position While independently controlling the rotation of said rotation of control plate 6| is effected by the syn driven shaft whereby the angular position of said chronizing armature 63. The position of notch ‘I6’ corresponds to the driven shaft is alterable with respect to said driv underlap portion of the drum 50 in relation to ing shaft; and a synchronizing magnet responsive gear | 2| will be forced to rotate as it rolls around the stopped bevel gear |20. Rotation of bevel gear I2| correspondingly rotates spur gears |23 20 the optical scanning system and also corresponds to the position of cam 12 connected to the drum opening the synchronizing switch ‘l0-1| by the cam projection 13. The synchronizing signal will cause synchronizing magnet 62 to be energized in 25 a manner already described to attract -armature 63 out of engagement from control disk 6|' and permit it to continue its normal rotation. The synchronizing signal accordingly starts the tele picture driun 50 rotating in proper phase syn-30 chronous relation with respect to the transmit ter drum as determined by the timing of the cyclic synchronizing signals. ' In the preferred embodiments of my invention, the telepicture drum is effectively maintained at 35A a “stand-still” if the drum is not in proper phase ' relation with the transmitter drum. If the drum is in the exact phase relation with the transmit ter drum as determined by the timing of the syn chronizing signals, a positive driving connection 40 is maintained between the driving motor and the telepicture drum, so that no slippage can be had therebetween at any time, particularly during the phasing periods. ’ In accordance with my present invention, phase synchronism is effected in a definite and positive 45 manner by superimposing the angular corrective motion upon the normal motivation of the drum while maintaining the positive driving connection to the drum. It willbe evident to those skilled 50 in the art that modifications falling within the broader spirit and scope of my invention are feas ible, and I do not intend to be limited except as set forth in the following claims. to cyclic synchronizing signals for arresting the Ca 10 15 20 rotation of said stop-plate in the event said driven shaft is not in synchronism until said driven shaft returns to synchonous position, one per revolution of said driven shaft. 4. In a synchronizing system, a driven shaft; a 25 driving shaft; gearing effecting a continuous me chanical interconnection between said driving and driven shafts; mechanism mechanically connected to and normally rotated with said gearing inter connection for independently control ' g the ro 30 tation of said driven shaft without di onnecting said gearing whereby the angular position of said driven shaft is alterable with respect to said driv ing shaft; and a synchronizing magnet responsive to received cyclic synchronizing signals for 35 cyclically arresting the rotation of said stop-plate until said vdriven shaft returns to synchronous position. . 5. In va synchronizing system, a driven shaft; a driving shaft; a driving connection from said 40 driving shaft to said driven shaft comprising gear ing effecting a continuous mechanical intercon nection between said driving and driven shafts; a stop-plate mechanically connected to and nor mally rotated with said‘gearing interconnection 45 for independently controlling the rotation of said driven shaft Without disconnecting said continu ousymechanical interconnection whereby the an ogular’, position of said driven 'shaft is alterable with respect to said driving shaft; and a syn v50 chronizing magnet responsive to cyclic synchro nizing signals for arresting the rotation of said stop-plate in the event said driven shaft is not in synchronism until said driven shaft returns Y I claim: to synchronous position, once per revolution of 55 1. In a synchronizing system, a driven shaft; a l 55 said driven shaft. driving shaft; gearing effecting a continuous me chanical interconnection between said driving and driven shafts; mechanism mechanically connect ed to and normally rotated with said gearing 60 interconnection for independently controlling the rotation of said driven-shaft without interrupting said continuous mechanical interconnection; and a synchronizing magnet responsive to cyclic syn. chronizing signals for cyclically arresting the ro 65 tation of said mechanism in the event said driven shaft is not in synchronism and until said driven shaft is in synchronous position. 2. In a synchronizing system, a driven shaft; a driving shaft; comprising gearing effecting a con 70 tinuous mechanical interconnection >between said driving and driven shafts; mechanism mechani cally connected to and normally rotated with said gearing interconnection for independently 6. In a synchronizing system, a driven shaft; a , driving shaft; a driving connection including gearing from said driving shaft to said driven shaft; a stop-plate mechanically connected to and 60 normally rotated with said gearing connection for independently controlling the rotationv of said driven shaft without disconnecting said gearing connection whereby the angular position of said driven shaft is alterable with respect to said driv .65 ing shaft; and a synchronizing magnet responsive to cyclic synchronizing signals for arresting the rotation of said stop-plate in the event said driven shaft is not in synchronism, to effect a substan tial stand-still of said driven shaft until said driven shaft returns to synchronous'r position, once per revolution of said driven shaft. WILLIAM G. H. FINCH.