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Aug. 9,1938. ' A. J. CAWLEY > v2,125,991 AUTOMATIC TELEVISION'SYNCHRONIZING APPARATUS Filed June 18, 1932 ‘ 3 Sheets-Sheet 1 Aug. 9, 1938. ‘ 2,125,9917 I A. J. CAWLEY AUTOMATIC TELEVISION SYNCHRONIZING APPARATUS Filed June 18, 1952 s Shgets-S?eet 2 " ' ‘ INVENTQR. Aug. 9, 1938. v ‘ ' A. J. CAWLEY - > , 2,125,991 , AUTOMATIC TELEVISION SYNCHRONIZING APPARATUS ‘ Filéd June 18,- 1932' * a Sheets-Sheet s Patented Aug'.9,1938" ‘ ‘ 1 2,125,991 , ‘ 4 UNITED STATES] PATENT OFFICE 2,125,991 , AUTOMATIC TELEVISION SYNCHRONI-ZING , APPARATUS ' Aloysius J. Cawley, Pittston, Pa. Application June 18; 1932, Serial No.‘.617,95'l 25 Claims. '(ci. 178—-69.5) This application is a. continuation in part ap- a friction drive, a rheostat or other electrical plication of my application for Television; Serial No. 455,127, filed May 23, 1930, which is now U. S. motor controlling means. Although the synchronizing .apparatus is shown Patent No. 2,026,610 of January 7, 1936 and of 5 Serial No. 468,117, ?led July 15, 1930 for .Tele- as being used with a television broadcasting sys— tern wherein the broadcast is periodically inter- 5 vision, both of which disclose synchronizing ap-‘ rupted, thus rendering a separate wave channel paratus. unnecessary, the invention includes any of the _ The invention relates in general to the trans-, mission of images by wire or wireless methods 10 from one place to another. More particularly, synchronizing means in a Separate Wave channel without any interruption of the television broad cast. ' it is concerned with the maintenance'of a rotating element at a receiving station in absolute A rotatable scanning element provided with a pair of electrical contact strips or segments hav ‘ synchronism with a rotating element at a transmitting station without any attention on the part ing an insulated segment between them and a Contact brush normally in Contact with this in 15 of the operator. Some of the objects of the invention are as follows, ‘ - 2° . . 10 sulated segment it the disk isin synchronism With 15 " a similar disk at the transmitting station. The The maintenance of synchronism without the use of a separate wave channelor separate con- contact segments acting to actuate an electro magnetic apparatus for altering the Speed Of the ducting circuit. ‘ The production of synchronism by means of the rotatable element, one of the segments bringing about acceleration of the speed and the other seg- 2o regular television broadcast current by means of ment bringing about retardation of the Speed Of a periodic interruption in the latter. A television scanning element provided with the rotatable element. The electromagnetic ap Daratus may also simultaneously or singly Oper ' transparent segments bearing symbols‘ or colors, ate a rheostat controlling the speed of the motor. , 25 or both, or other identi?cation means, which in- ' A relay switch at the receiving station which 25 dicate the relative position of the rotating element at the receiving station with relation to a stationary light source which is illuminated at the time ‘of interruption of the broadcast televi30 sion current at the transmitting station. The maintenance of synchronism by means of- photoelectric cells and circuits in cooperation‘ - with transparent segments carried on a rotating scanning element,‘ the photoelectric cells being acts to maintain the synchronizing circuit open for the greater Part Of the Period of rotation of the scanning disk, the synchronizing circuit be ins closed for' a brief interval corresponding to the period of interruption of the television broad- 2.0 cast at the transmitting station. . A stationary stroboscopic light source at the receiving station which illuminates the rotating element for a very short period corresponding to ' 35 in cooperation with means for controlling the _'the period of interruption of the broadcast at the 35 speed of the rotating element. ‘ transmitting station. This gives the illusion of A rotatable scanning element bearing trans- the rotating element standing still in the posi parent segments and re?ecting means in coop- tion it occupies relative to the disk at the trans . erative relation to ‘said segments to re?ect'the ‘19 light‘traversing those‘ segments into proper photoelectric cells. _ / ‘ mitting station as regards synchronism; This constitutes an excellent synchronisrn indicator. 4O A contact strip placed on- the rotatable ele An automatically controlled friction drive in ment at the receiving station at a point on the ro cooperative relation with a rotatable scanning tatable clement or'diSk which will be directly 09 element. consisting of a friction wheel in adjust- ' P051158 two Statlonary Contact brushes when the ti; ii able Contact or engagement with the ‘Scanning . rotatable element is insynchronism, the brushes 45 element, and electromagnetic mechanical means ‘being ifnnett‘if tgignnigrllgijgzgce ,ggiznaliffgg: for adjusting the position of this friction drive gage; ggygcell‘fent synchronislh ind16 atbr with relation to the rotatable element, in order 50. to vary the speed of the ‘rotatable element and‘ . . thereby bring it into Synchronism- A mtata-ble ?mnnmg element pmvided with transparent 5%‘ merits controlling the operation of photoelectric cells, and the latter controlling the operation. or » > . '. Also‘ light sources or electromagnetic mdmat _ ing means in cooperative relation with the con- 56 tact segments carried upon the rotatable element whereby, as the latter are ‘actuated, either a light isi?ashed or-else a pointer indicates whether the rotatabievelgment 15' ahead of 013 behindsyhchro 56 electromagnetic‘, mechanical means for adjusting nism.‘ 55 2,136,991 An adjustable friction drive provided with a lever controlled by electromagnetic means, the lever also acting to operate a motor controlling concentric shafts of the synchronizing appara rheostat or other controller.‘ tlcation of Figure 8. tus. ' tween a receiving station ands, transmitting sta tion is illustrated in Figure 1. No separate wave channel is required for the attainment of syn chronism. At the transmitting station the in conjunction with a friction speed drive to fur ther regulate the speed of the rotatable scanning . ' “ A switch operated by the centrifugal speed control means whereby the synchronizing current broadcasted television waves are interrupted dur ing a short portion or period of each revolution of the scanning disk. As in most television sys is‘ not turned on until the speed of the rotatable element has reached a speed approximating syn tems, a revolution of the disk generally com chronism. pletes a single picture, it necessarily follows that An electrical switch operated by the centrifu 15 gal speed governor controls the speed of the mo after each image is televised, there is a very short interval during which no broadcast takes place. This does not introduce any more serious difficulty or defect than that already existing in ordinary motion pictures, as there, between im~ ages there is a short interval of darkness dur 20 ing which the ?lm is shifted. The standard Nipkow disk is mounted as shown at l upon shaft 4. The holes or lenses in this tor either by means of a rheostat or other motor speed controlling means. A rotatable scanning element consisting of a ?at disk to which lenses or prisms, or the like 20 are cemented, the disk being coated with opaque paint or the like. Such a disk is very easily and cheaply manufactured as compared to an ordin nary scanning disk employing lenses, or even those employing holes for scanning purposes. 25 disk are shownv at L. lamp 2 is shown in cooperation with the image 25 area in the usual manner. Collector ring 3 is which accommodates a shaft of irregular cross mounted upon shaft 4 but insulated very care the invention. ' ning apparatus which is provided with means'for indicating synchronism consisting, of a light mounted on said disk. , Figure 1a is a side elevational view of the ap— paratus shown in Figure 1. . 50 television current, after being ampli?ed, is sup plied to the neon lamp 2 by means of the wires 35 A and B. Part of this current 'is shunted to the synchronizing indicating lamp 9 by means of wires 1:. and 0. As before stated, the television broadcast is interrupted for a short interval dur ing. each revolution at the transmitting station. 40 lected as at the extreme lower portion of the orbit of the lamp as indicated by i, then, if the receiving disk is in synchronism with the send ing station disk, the scanning lamp y will de 45 scribe a path of light p which is interrupted at nism with the transmitting disk, then’the point synchronizing apparatus. of interruption in the path of light 9 will be either to the right or to the left of the position 50 shown in Figure ‘i. For instance, if the receiv ing disk (shown in the figure) is in advanced Figure 3 is an elevational view of the inter rupting apparatus at the transmitting station, t Figure 4 is a side elevational view partly in cross section of the scanning apparatus shown 55 in Figure 2 in part. ' - Figure 5 is a front elevational view of a scan ning apparatus provided with synchronizing means consisting of a variable speed friction drive controlled by photoelectric means. Fig. .50 is a view of the apparatus shown in FiBure 5 with a motor rheostat control added. - drive in conjunction with electric contact ele _ _ - Figure 7b is a cross section of a special scan ning disk. _ t the synchronizing lamp 0. The lamp 0, since it ?ashes only during a small portion of the rev 65 olution period 01' the disk I and since the disk , ' Figure 7a is a modi?cation of part of the iris tion drive. retarded isochronism, the point i will be any where between a and the lamp 2 in the right half of the circle. If the receiving station disk is in asynchronism with the transmitting station diskpthen as the interruptions are occurring at 60 . will be no gap f in the path of light described by 65 ning apparatus provided with a variable speed , 9 will be anywhere between a and the glow lamp . I in the left half of the circle. ' If the disk is in 55 distinct interruption will be discernible, and there Figure 7 is a front elevational view of a scan ments carried on av rotatable disk. isochronism, the point of interruption in the path different points during each revolution, no clear - - Figure 6 is a side elevational view of the ap paratus illustrated in Figure 5. ' Figure 8 is a front elevational view of a scan ning apparatus employing a variable speed fric ' tion drive and a centrifugal speed governor. 75 ed upon the disk I and is in electrical connec tion by means of wires 11 and c with the shaft 4 and the collector ring 3. The broadcasted ning apparatus provided with a photoelectric shown in Fig. 2 in part. 70 the shaft 4. The synchronizing lamp g is mount 30 ' i. If the receiving disk I should be in isochro Figure-2 is a front elevational view of a scan . fully from it. Brush b makes contact with this ring, while ‘crush 0 makes contact directly with i Assuming that this interruption is arbitrarily se Figure l is a front elevational view of a, scan 45 The neon, or other glow A driving means consisting of a motor provided with a hollow shaft of irregular cross section, section, the latter being attached to a, centrif ugal governor. A variable speed friction drive 30 wheel is carried on inner shaft. The variable speed friction drive and the centrifugal governor thus act jointly to maintain the apparatus in synchronism and at constant speed. Other advantages and objects of the arrange 35 ments will be apparent from a consideraion of the following speci?cation and claims when read in connection with the accompanying drawings wherein the various ?gures thereof represent in ‘a conventional manner the principles covered by 40 . An apparatus for indicating synchronism be ,A centrifugal speed controlling means acting element. ‘ Figure 9 is a front elevational view of a modi Figure 8a is a cross sectional view 0! the two makes about twenty revolutions per second, con stltutes the equivalent of a stroboscope with the rotating disk I. If the disk I is in absolute syn chronism, there will always be a dark area at i, 70 . and the path 9, consisting of a broken circle will appear stationary. The synchronizing lamp 0 takes a very small amount ofthe television broad ’ cast current. as it is made very small. Figure 1a is a side elevational view of the apps 76 3 2,125,991 . ratus illustrated in Figure 1. The reference char acters have the same meaning. The apparatus illustrated and described in connection with the ‘above two ?gures. discloses merely a synchronism may desire. Transparent'segment 6 may be I colored blue and suitable reference characters printed upon it.- The segments may be made much smaller, i. e., only a little larger than the diameter of the shaft 4, if desired. smallness is indicating means. Figure 2v illustrates another modi?cation, which includes means for maintaining the disk in synchronism with the disk at the transmitting station. The television broadcast is received by '10 desirable, as the speed of the brushes in cont t with the collector rings in the modi?cations to. be later described, will thereby be greatly re--lv duced. The segments are shown as increasing in ' the usual wireless apparatus including an antenna width as the distance from. the opaque portion in and is illustrated at d. An amplifying apparatus ' creases. ' Theobject of this is to increase the is shown at K, which intensi?es the broadcast amount of light that reaches the photo cells (to current’ as much as possible. Wires E and D‘ be described shortly) the farther the disk is out conduct the ampli?ed current to the'glow lamp 2, . of synchronism, and therefore to correct the asyn which is shown in the usual cooperative relation chronism as quickly as possible.‘ The segments 15 ‘with the scanning diskll provided with holes‘or may increase uniformly in width, instead of in a lenses L. A portion of the amplified current is stepped manner as illustrated. As the lamp ‘I is shunted by the wires F and G'to the relay R, only ?ashed on for a short interval of time, and which acts to open a circuit including a syn as this interval is ‘always in accordance with the 20 chronizing lamp 1, shown in dotted'lines on the‘ time during which a certain portion of the disk 20 opposite side of they disk I. The current at. the is successively opposite the lamp ‘I during each transmitting station is interrupted for a short’ revolution, at virtuallyithe same point, a strobe interval during the revolution of the disk at the scopic eifect is produced. Suppose that 45 is transmitting station. This inerruption will take opposite the lamp 'l at each revolution, then it place at a de?nite, prearranged point of the path will be seen as stationary at that point. The of. rotation of the disk, and is indicated in the same is- true of any other reference character ?gures of this application at the extreme lower portion of the circle described by the disk. The relay R is so designed that it will respond readily at any other point on the disk if that particular point is opposite the lamp 1 during a series of successive revolutions. As synchronism is estab 30 to a vibration rate of twenty per second. lished by proper adjustment,‘the character 45 The conventional representation of a relay is shown, '. however, the armature of the relay together with its spring or other equivalent is such that it will readilyv vibrate at the frequency of television image change, which is from ten to twenty per second according to the degree of continuity of image that is desired. When the broadcast is being received, the armature of the relay R is' attracted towards the electromagnet and the cir composed of the wires H and I, the source 40 cuit of power Pr and the lamp ‘i is opened. However, during the short interval of a revolution that the broadcast is interrupted, the lever of the relay R is released and is attracted by its. spring (not shown) to the right and the above circuit is closed. The lamp ‘i is then illuminated. Disk i is provided withtwo transparent segments 5 and 6. Those transparent segments are separated by a relatively small portion of opaque disk. This. 50 latter is shown as just covering the lamp 1!. Therefore, when the receiving disk is in synchro nism with the sending disk, the lamp 1 is illumi nated only when the short opaque space between the two transparent segments is just in front 55 of the lamp, and its light cannot be seen. Syn would move to the position shown in the illus tration from that in front ofv lamp l. Thus the degree of advanced or retarded isochronism is readily determined by this apparatus. The seg ments b and t need not be of a ‘size equal to ap proximately a semicircle, as shown, but may be‘ much shorter. ' For instance, they may be only 45 or, 90 degrees in extent. several different ways. By one method, photo 40 cells P and P’ are arranged to ‘be excited, de pending upon whether the disk is in advance or behind that at the transmitting station. A prism r. or a series of such prisms is placed over the windows or transparent segments 5 and 6. That over window ‘5 is illustrated by dotted lines in ‘ Figure 3, which illustrates the fact that the light is reflected downward into the photoelectric cell 45 P’. Segment 6 has a’ prism rb placed over it with its base turned inwards towards the center of the 50 This is illustrated in Figure 4 and shows that the light is re?ected upwards into ‘photocell P. The photocells are shown as being of ‘the . circle. > cylindrical type. chronism is, therefore, indicated by absolute darkness. If the disks are rotating in adminnism and the receiving disk is behind ‘the trans 60 ' , Automatic synchronism may be attained in It is to be noted that the width of the transparent segments 5 and 6 increases towards their opposite'ends. The result is that, 55 the'greater the disk is out of synchronism, the more light that will be admitted to the photo- . mitting disk, then the transparent segment 5 will cell and the greater the corrective response encroach upon the lamp 1 and be interposed be~ . rought about by the circuits associated with the 60 tween the- lamp and the observer. The re cells. ' Accordingly, the wire T leads to an ac suit is that the light of the lamp will be seen. i celerating means, while the wire S leads to a The segment 5 may be colored red, or any other retarding means. If the disk is behind, cell P’ color,v and the appearance of this color will indi is actuated and the accelerating means brought 65 cate that the disk is behind the transmitting disk. In addition, reference characters, such as num bers indicating the number of degrees the receiv~ ing disk’ is behind the sending disk mliytbe added, i as for instance45 shown in the ?gure, ‘when it is 70 in position opposite the light itw'ill-show that the disk is 45 degrees behind. - The arrow turned backward in‘ relation with 45 indicates that the disk is behind. 4_5_~and the arrow. therefore, in dicate that any "reference characters may be 75 placed on the transparent segments. that one into play, while if the disk is ahead,‘ cell R is 65 actuated and the retarding means brought into play.v Wire C is a common return wire for both circuits, i. e., acceleratingand retarding. Figure 4 illustrates the fact that the disk I may be made of any transparent material, such as 70 Bakelite (transparent) plate glass, or other, and the prisms rand rb cemented to them.‘ The prisms-r and T1) may be arranged side by side seg mentally over the entire extent of the transpar .ent_sectlons 5 and 6. The cement used for at 76 2,125,991 . 4 taching the disk and the prisms or other optical elements, such as lenses, may be Canada balsam. Lens making, prism making and plate glass mak ng have all reached the dignity of ?ne arts. They are almost perfect. The lenses, prisms and plate glass can therefore be made very cheaply and accurately. It is only necessary to cement the various optical elements to the disk. A very de sirable' combination is that of a disk made of 10 transparent Bakelite to which cylindrical lenses, or other optical elements are cemented. This gives a disk which is of itself very light, but the peripherally located lenses lend peripheral weight which‘will develop when in motion a desirable 15 centrifugal force which will tend to maintain the disk in uniform motion. The portions of the disk which are unoccupied by lenses, prisms, etc., may be painted by means of dark, opaque paint. Thus the expense of drilling holes in a disk in 20 order to mount the lenses is dispensed with. An other desirable quality of the Bakelite disk is that it is not nearly so fragile'as glass, consequently, a much thinner disk may be used. Figure 5 illustrates another modi?cation of the 25 invention and also shows a means of correcting asynchronism by means of an electromagnetic arrangement. The amplified television current, whether received by wire or wireless means, is conducted by wires A and B to the neon or other 30 glow lamp 2 and also to the relay R. The scan ning disk I is here shown as being provided with transparent segments of different sizes, i. e., they are segments of circles of different diameters in order that each operates a diilerentphotocell without using prisms. Each transparent _ seg ment can only be opposite its own speci?c cell, and can never be opposite the other cell. The television broadcast is interrupted periodically at the transmitting stationv during a very short 40 interval during each revolution of the disk, as before stated. The point in the revolution of the disk at which this interruption may take place will be agreed upon by the various broadcasting result that the jaw J since the lever is pivoted at 1‘, will move to the right. The motor M is shown as provided with a square, or rectangular, or other irregular cross section shaft u. The wheel W is‘ slidable laterally on this shaft but cannot ro tate upon it. It will be seen that the jaw J moves the wheel W with which it engages, towards the center of the disk I. This means, obviously, that the speed of the disk will be increased. Pr repre sents any desirable source of power or amplifying 10 means. If the disk I should gain over the speed at the transmitting station of the disk located there, then transparent segment 6 will be opposite the lamp 1 when it is illuminated and its light will reach the photoelectric cell P’ with the result that solenoid 9 will be actuated and a tug at its armature attached to the lever I will cause the jaw J and wheel W to move to the left towards the periphery of the disk I, resulting in a reduction of the speedof the disk. The ?ashes of the lamp ‘i 20 take place about twenty times per second or more if the best television reception is to be attained. However, a lower speed may be used. The wheel W is mounted upon shaft u in such manner that it must rotate with the shaft. It is slidable upon 25 the shaft and can therefore be shifted to new positions. The friction wheel W engages with the disk I which is provided with a suitable surface to prevent slippage, such as leather, rubber, etc. The wheel W may be provided with a peripheral 30 ring of adherent material such as leather or rub ber as shown more clearly in' Figure 6. If de sired, a special friction disk may be attached to disk I. As the transparent segments 5 and 6 are provided with reference characters, such as those 35 described in connection with Fig. 2 above, and since the light is ?ashed on during a very, very small fraction of a second and repeated about twenty times per second; the particular reference character will be seen opposite the light and will 40 be perfectly legible, as the light is extinguished during the time thatvthis particular character moves around with the revolving disk. The ref companies, but it is here shown (according to ' erence character will apparently be standing still due to this stroboscopic effect. It is to be noted 45 which is illustrated) as taking place when the that there is a constant adjustment of the posi opaque portion located between the two transpar tion of the wheel W relative to the shaft 11.. Just ent segments is at its extreme lower position. as soon as there is the slightest deviation from As before explained, the circuit containing the 'synchronism the corresponding photoelectric cir cuit is actuated and the friction wheel W is shifted 50 source of power Pr and the synchronizing glow to a position to correct this deviation. This oper (or other) lamp ‘I, which are connected by the wires H and I, is broken during the period of ation is carried out in a purely automatic man interruption of the television broadcast from the ner. The motor M may be a synchronous motor when the question of synchronism is mostly in central station. If the receiving disk I is in ab volved in a correction of isochfronism'or a con 55 solute synchronism with the transmitting station disk, then the lamp 1 will be illuminated'only version of isochronism into synchronism. The motor may be a phonic motor. The motor M may , while the opaque portion between the two trans parent segments is directly opposite thevlamp, be provided with an independent'speed govern ing apparatus so that its speed is constant, as and no light will be seen. Two cylindrical photo electric cells P and P' are placed directly opposite .illustrated in Fig. 5a. However the present dis 60 the lamp 1. If the disk I is in synchronism with closure is concerned with means for keeping the the disk at the transmitting station, neither cell scanning disk in cooperative relation with any will receive any light.‘ If the disk I should lag type of motor in absolute synchronism without behind the disk at the transmitting station, then any attention whatever on the part of the oper segment 5 will be found opposite the ato'r. This feature will be described in greater 65 as transparent lamp ‘I when itis illuminated and the light will detail in connection with later ?gures. Figure 6 is a side elevational view of Figure 5. enter photoelectric cell P. Depending upon the type of cell (the speed of response of selenium The television broadcast is received by the wire cells-has been greatly increased of late) either less apparatus d and amplified by suitable cir current will be permitted to flow, or in the vacuum cuits at K and the ampli?ed current led to the 70 w tube type of cell a. small current of electricity neon or other lamp 2 by wires A and B and to will be generated in the cell and this will be ampli; ‘ the relay R. The relay breaks the circuit con ?ed by the amplifying or power circuit Pr’, and taining the ampli?cation or power element P1’, the solenoid I will receive this current and tug which is connected by the conductors H and I to at the armature attached to lever l, with the the synchronizing lamp ‘I. This lamp is there 75 45 the position of the disk. at the receiving station, w I 2,125,991 ‘ fore, only illuminated during a very small por tion of the revolution of the disk I. Disk I is mounted upon the shaft 4; the latter is sup ported by two ‘strong bearings. The friction wheel W with its peripheral ring of adherent material is ‘shown mounted upon the shaft u of irregular cross section, which is here shown as square. However, a very desirable cross section ' of a shaft would be a rectangle.‘ Another form would be that of a cross. The motor M rotates the shaft 1!. and the friction wheel W. The latter j engages'with the surface of the disk I, which also ' may be provided with an adherent surface. The lever l with its fulcrum is clearly shown with its 15 jaw J engaging‘the wheel W. It is to be noted that the lever 2 should be designed to be per fectly balanced so that it will stay in any noel tion in which it is placed. The invention is not limited to this feature of the lever however. The synchronizing lamp ‘I is shown opposite to-the 20 two photocells, one of which is designated P. The accelerating solenoid is shown at 8. The ' photoelectric cells are shown as being of the cy lindrical type. . 5 battery. However, since the disk I is in syn chronlsm with that at the transmitting station, the brush V rests upon the nonconductingin terval between the two contact strips 5a and 6a and no current can pass from the battery Y or other source of power. The glow lamp U is con nected to wire l0 which is in turn connected to the relay R so that when the latter closes, the synchronizing circuit, ‘even though no current ?ows through the contactstrips, still the lamp 10 U will be ‘momentarily illuminated ‘for its stro boscopic effect of illuminating the disk which may have various symbols located upon it indi cating its position. as regards synchronism. In fact, the position of the contact elements them 15 selves thus serve. The lamp U may be a glow lamp of any desired type, but is not limited there to. The disk i is supposed to be made of ‘some insulating material, such as Bakelite. However, if it is made of metal it should be covered with 20 a disk of insulating material upon which the contact strips 5a and 6a are ‘mounted. Suppose the disk I is lagging behind the trans mitting disk, contact strip 5a comes in'contact with the brush V, and the battery or other cur 2,5 The lever I may, in one modi?cation be that of a rheostat governing the speed of the motor rent passes from Y to the relay switch R'to wire Ill, to brush V to contact strip 5a to wire 8 to M. This may be used in an arrangement where in the motor M is directly attached to the shaft collector ring 20, to brush X and by wire to the solenoid 8 which exerts a torque upon the arma 4 upon which the disk I is mounted. Orpthe ar ' ture of the lever I which is pivoted at f. The 30 rangement shown in Figure 5a may be used and in 30 which the lower half of the lever l constitutes current returns from the solenoid 8 to the bat“ virtually the arm or crank of a rheostat Ta. or tery or other source of power ‘Y. The motor actuates such a rheostatlc'arm or crank. Or it may actuate any type, of motor speed control. > 35 A modi?cation "of the invention which dis penses with the use of photoelectric cells in the synchronizing circuits is illustrated in Figure ‘l. M- is provided with a shaft of irregular cross sec tion, as already explained and has the slidable wheel W mounted upon it. The wheel W. makes 35 frictional contact with the disk l and drives it. When the solenoid 8 attracts the armature at .The television ‘broadcast current is led into the tached to the lever I, it causes the clutch J to amplifying apparatus K by means of the wires move the wheel W towards the center of the disk I, with the result that a greater speed is im 40 A and B; The ampli?ed image varied current is then supplied to theneon lamp 2 and'the second parted to the latter. If the disk i is gaining amplifying apparatus K’. The current is then on the transmitting disk, then contact strip Ba supplied to ‘the relay R. The conductors E and will engage with brush V and the current will D connect the glow lamp 2 in circuit. ‘The Nip~ pass from the battery Y to the relay R, to wire 45 kow disk or its equivalent is shown at l. The ’ Ill, to brush V, to contact strip 6a, to wire t» 45 , holes or lensesare shown at L and are arranged to collector ring. 12, to brush Z,-to solenoid 9 and in a spiral line in the usual manner. Instead of r back to Y. The solenoid causes the lever to be ' .the transparent segments described in connec» ‘moved to the right with the result that the jaw tion with the previous ?gures, ‘two contact strips J moves to the left and the wheel W is shifted. - 5a‘ and 6a are attached to the disk I.'. Those strips towards the periphery of the disk i which re“ 50 are shown of varying width, which is shown as duces the speed of the latter. There is thus a increasing progressively from the lower end of the strips to the upper in the ?gure. The object of this is to provide a greater contact area to the various brushes V and thus to furnish a greater current to the synchronizing circuits in proportion to the degree of asynchronism pres ent. A single wide brush or a plurality of small-- constant automatic effort. on the part‘ of the synchronizing apparatus to keep the disk in ab solute synchronism. No attention is required on the part of the operator and thisis true regard 55 less, of the type of motor used. Although no separate synchronizing current is required with the disclosed apparatus, still the invention covers ' the use of the apparatus in a separate synchro» nizing currentarrangement. The attainment of If brushes of highresistance are used, the vary ing area of contact of 5a and to will cause cpr ‘ synchronization by the interruption of the broad respondingly varying‘ amounts ‘of electric cur: cast of the television is an invention over the ‘ rent to pass. , As described in connection with employment of a separate synchronizing wave the previous figures, the broadcast current is channel or separate synchronizing circuit, if the apparatus is used with wires. The invention 65: periodically interrupted at the transmitting sta tion at a predetermined point of the revolution therefore, covers the use of the apparatus with a er or narrower brushes may be provided at V. of the transmitting disk. This isfor the present. separate wave channel or circuit. - disclosure assumed to be at the lowest point'in ' The wheel W may be provided with means for . the circle described by the rotating disk. Con holding it more securely in the position on the ' sequently, the apparatus illustratedin Figure '7 . shaft in which'it is placed, and at the same time 70 is in a position that it should occupy when the being readily shiftable to a new position by the disk I is in synchronism with the transmitting law or clutch .1. Figure '7a shows the wheel equipped with very delicate ?exible strips of metal disk. The interrupted broadcasted‘image cur rent has permitted the relay to move its arma . ,2! which make'contact with the shaft 14. The -75 ture to the left and close the circuit through the ?at face of the shaft u may be roughened or pro- 15 6 2,125,991 vided with fine ridges as shown at 22, which are depressed below the surface of the shaft u in . order not to interfere with the movement of the wheel W. The lever I should be well balanced with regard to its fulcrum ,1‘, just as the arm of a balance, so that it will have a tendency to re main at rest in any position in which it may be placed. A handle his shown for manual adjust ment of the position of the wheel W inorder to 10 manually attain synchronism, if desired. mg I‘! in order to permit it to shift or slide through the Journal bearing. The end of the shaft u will project farther and farther to the left beyond the journal I'Ia as the speed'is accelerated. All of the shaft that passes through the governor I6 is ‘rounded. Thus a centrifugally operated speed governor is added to the previously described ap paratus. If desired the governor I6 may have attached to it the contact brush 23 which makes contact with the contact point or strip 25 when The disk I may be made of plate glass or trans . the motor has been brought up to full standard parent Bakelite. The lenses La may be of glass synchronizing speed. The brush and contact and plane-convex and their ?at surfaces cement strip are connected to the synchronizing circuits ed to the disk I. The portions of the disk which in such manner that contact is not made between Hand 25, and consequently the latter are not 15 are unoccupied by any lens or other optical ele ment may be painted with an opaque paint or its energized until full speed has been attained by equivalent. A transparent Bakelite disk I with the motor M and wheel W. The disk I is shown glass prisms and lenses is a good construction. in synchronism with the transmitting disk and at The expense of boring holes in the disk to accom the point it should occupy if it is in synchronism '20 modate the lenses or other optical elements is with the transmitting disk when the broadcast is 20 done away with. In manufacturing such a disk, interrupted. The relay R has closed the circuit a form is made which consists of a flat board, or and the current passes from the battery Y to the like, having spherical depressions located relay switch R to brush V to contact strip 11, to therein and the depressions arranged in a spiral. brush a: to electromagnet I9 by means of wire ISa and back to Y. The armature-indicator I5 is 25 25 The lenses are simply placed in those depressions, .which they ?t snugly and their flat, upturned attracted to its position indicating synchronism faces coated with a suitable cement, such as on its dial (not shown). It will be noted that the Canada balsam. The disk I is then laid upon this‘ contact metal or other conducting strips 541 and ?at surface including the cement covered lens 6a are made much smaller than those previously shown. If the disk I is lagging behind the trans 30 30 surfaces and left to harden, when it is removed together with the ?rmly adherent lenses. The mitting disk, then the strip 5a is in contact with cost of manufacture is thus greatly reduced. If the brush V during the time thatthe relay R such a disk were moulded of glass, for instance in closes the circuit and the current passes through one piece, the lenses (since they are molded) strip to to collector ring w to brush X to electro magnet I 9, which attracts the armature-indicator 35 would be unsatisfactory from an optical stand point. To grind the lenses which have been cast I5 to the position indicating retarded isochro in one solid piece with the disk would be pro nism. If the disk I is running ahead of the trans hibitive and almost mechanically impossible. By .mitting disk, then contact strip Ila makes contact the present method, the lenses have been manu factured in accordance with the best principles set down by optical manufacturers, the same is true of the plate glass or the Bakelite disk.‘ The disk andthe optical lenses or other optical ele ments are then combined by the simple process of 45 placing the lenses in the depressions in the form and simply coating their upturned faces with ce ment and the disk laid on. All of the expense of “laying out” the spiral, boring the holes in the disk and ?tting the lenses into the holes is dis pensed with. Oviously a disk made of Bakelite '50 with cemented lenses could not be moulded in a single piece. This is a very desirable embodiment of the invention. After the disk is formed, the unoccupied portions are coated with opaque paint. Another modi?cation of the invention is illus 55 trated in Figure 8. The motor is shown at M. It is provided with a hollow shaft ua of square, rectangular or other irregular cross-section. The square or other irregular cross-sectioned shaft u 60 fits into this hollow shaft and is unrotatable rela with brush V, and the current passes from Y to relay switch R, to brush V, to collector ring or contact strip 60, to brush Z, to electromagnet 20. The latter attracts the armature-indicator I5 to the position indicating advanced isochronism or accelerated asynchronism. The current then passes from 20 to the solenoid 9, which attracts 45 the armature attached to lever l and pulls the latter to the right with a resultant shifting of the wheel W by means of the clutch J towards the periphery of the disk I, and the latter is slowed down. In the former case, where the disk I was 50 running behind the transmitting disk, the cur rent returned from the electromagnet I9 to the solenoid 8 and from thence to the source of power Y. The solenoid 8 attracted the armature at tached to lever l to the left, with a consequent shifting of'the wheel W to the right and towards the center of the disk I with a resultant speeding up of the latter. Thus a means is provided for indicating by means of a pointer and dial, the character of asynchronism, lsochronlsm or syn~ 60 tive to the shaft M. It may be readily slid in and ‘ chronism that may'exist at any time. out of the hollow shaft ua. The shaft it turns in The jaws of the clutch J are turned down In the the journal I‘! and it is here of a round cross plane of the paper and two wheels Ja are rotat section tolaccommodate the 'journal bearing sur ably supported on small shafts that are attached 65 face. The shaft ‘is further journalled at I'M. A ' to the turned down ends. The wheels Ja may be centrifugal governor I6 of any desired well known coated with a ring of leather or rubber or other type is shown in cooperative relation with the adherent surface. The purpose of those wheels shaft u. As the speed increases, the balls fly out? is to eliminate the friction that would otherwise ' ward from the shaft in the well known manner. 70 In sodoing they pull the shaft it towards the left and consequently shift the friction wheel W to the left, or towards the periphery of the disk I With‘a ‘resultant decrease of the speed imparted by the shaft u to the disk I. The shaft, it is to be 75 noted isrounded for some distance from the bear exist between the clutch J and the wheel W. The synchronism indicator consisting of the elements I5, I0, I9 and 20 may be omitted if desired. It is a very convenient and useful part of the apparatus, however. .The solenoids 8 and 9 in conjunction with the ‘lever I operate the friction drive W for the pur- 75 V 2,125,991 7 pending upon the interruption of the television broadcast to maintain s'ynchronism. pose of maintaining synchronism. However, in one modification of the invention, the lever I may . The arrangement of the transparent or con ducting segments with the opaque or insulating‘ segment located at the lower portion of the va rious ?gures of the drawings is such that it might be regarded as a means of determining the posi be used to operate a rheostat or other speed con trolling means governing the speed of the motor M. In another modi?cation, the lower end of the lover I may be arranged to operate a rheostat, or other motor controlling means in connection with tion of the disk during the stroboscopic illumina motor vM. Thus then, the solenoids and lever would control the speed by means of the friction v10 drive and motor current control, while the cen trifugal governor It would regulate the speed tion of the disk. - (The upper portion or interval is to correct the irregularity of speed in an elec tric motor known as “hunting”, which is well known and understood to those skilled in the art. between the two segments may be much closer, 10 in fact the contact segments are placed as nearly as possible to each other without actually making , -contact with each other.) This arrangement may therefore be regarded as a position indieating arrangement, as it indicates the position 15 in which the disk is located during the momen provided with roller bearings m, which ?t close Many modi?cations?f the relationship of the from a standpoint of momentum. A very im- ‘ portant function performed by “the governor I6 Figure 8a illustrates a cross section of the two tary illumination produced by-the intermittent vshafts tar and u. The hollow-shaft ua is shown as _' synchronizing current. ly to the inner shaft it. Thus the two shafts are ' centrifugal ‘speed governor to the disk are pos-' 20' absolutely unrotatable relative to each ‘other, and sible. For'instance, Figure 8 may be regarded as yet shaft u may be slid in and out of the hollow turned on its right side, when the centrifugal shaft ua with very little resistance, due to the governor would be found to be located at the top _ roller‘ bearings. 25 of the revolving disk. The operation would then » be such that when the balls are centrifugally I'D-r 25" In the operation of the apparatus, the solenoids and lever I act to maintain synchronism between tated outward, the shaft is permitted to vdrop the transmitting disk and the'receiving disk I. ' downward through the journal H. The wheel W then, instead of being located in the upper half They are constantly at work correcting all irreg ularities of synchronism. They cannot, however, of the disk as illustrated in the ?gure, ‘would be in contact with the lower half of the disk. Then, correct the speed irregularity known as “hunt ing” and it is principally for the correction of ‘this . when the increased speed rotated the balls or other centrifugal elements out‘wards, the wheel ‘irregularity that the centrifugal governor i6 , is provided. It is to be noted that the lever Z shifts W would be lowered to a point nearer the periph the wheel W on the shaft it, while the governor l6 ery of the disk and the speed slackened. Many other modifications‘ readily suggest themselves 35 -, shifts the shaft 11. and wheel W as a single unit. There is therefore, 'no interference between" the without departing from the spirit of the inven- - operation of those two speed controlling elements. tion. In another modi?cation, the Jaw J might be ' The brush 23 attached to the centrifugal speed a governor and the contact 25 may be connected. in . placed on guide rods, as described in my applica tion Serial No. 468,117 or July 15, 1930, and an 40 110 the synchronizing circuit between Y and R as illustrated in Fig. 9, and the latter will thus not armature fastened to the jaw. The solenoids ll be operative until the disk has been brought up and 9 or their equivalents would be placed in co operative relation with a pawl and ratchet, by to approximately synchronizing speed under con trol of the centrifugal governor It. The contact ' means of which it would be moved to new posi tions. '25 is shown as a strip. but it may be a button, thus making contact for ashorter interval of speed variation. The end of the governor i6 ‘ad jacent the bearing Illa is provided with a groove into which a tongue forming part of Ila projects and thus holds the ring of the governor always adjacent the hearing "0). ‘The shaft u is there fore, pulled to the left as the speed increases. However, the position of the motor M and the governor l6 might be reversed as shown in Fig ure 9, and in that case, the ring of the governor adjacent "a would not be attached thereto while it rotates. Instead, the ring oi‘ the governor It adjacent the bearing i1 would always be in con tact therewith, and the opposite end or ring of 60 the governor would move with the variations in speed. An increase of speed would then push the shaft away from thegovernor, and the wheel W would be pushed peripherally with a decrease of ‘ speed, since the position of the motor M and the governor it would be reversed. Many other mod i?cations readily suggest themselves to ‘those skilled in the art, and they are all within the spirit of the invention. . 1 Attention is called ‘to the fact that ‘although the 70 impulses in the synchronizing circuit are of short duration, still they are repeated at the rate of twenty per second and are‘ somewhat similar to ~ a Farradic current and possess a cumulativeei'iect while they last. As previously mentioned,‘ a sep 75 arate wave channel might be used instead of ee 45 The disks shown in the various figures might be regarded also as the disk portion of a cylinder-_ disk scanning element, the scanning holes or‘ 'lensesbeing carried on the cylindrical surface, while the synchronizing elements would be car ried on the disk portion of theelement. 50' Although the synchronizing apparatus is shown in the .?gures as being arranged to operate dur- » ing the time that the televisionbroadcast is in terrupted, it is to be distinctly understood that 55 a separate wave channel or a separate circuit may readily be used without departing from the spirit of the invention. , . The brush 23 in Figure 8 is supposed to be mounted upon a. pair of stationary guides and 60 engages in a. groove in the ring of the ‘governor i6. Howeirer, many modi?cationssuggest them selves.v , For instance, the end oi.’ the lever or shaft it moves to the left of the journal i‘lo to various extents depending‘ upon ‘the speed. ‘One 65 or more fulcruxned levers having one of their ends . in firm contact by means‘ of a spring or the like against the end of the shaft may be. used for the operation'ofspeed controlling means whether rheostats or other. Their free endsmay con stitute part of ._a rheoatat arm, or may be in con tact with various contact segments of speed con trolling means. ' ' » _ a e The present disclosure is especially concerned with thdmaintenance of synchronism of television 75 8 2,195,991 sets in isolated places where no synchronous mo“ reproducing an image from a periodically inter tors operated by conventionally phased currents rupted image varied current, two transparent are available. In cases where a motor is operated segments carried on said rotatable element, an opaque interval separating said transparent seg ments, saidv opaque interval being opposite a . by a dry or a storage battery, means are disclosed whereby the set is maintained in synchronism without any attention on the part of the operator other than initially turning on the current. The rheostatic control of the motor by means of the centrifugal governor will correct ‘speed variations 10 due to battery deterioration or other change. At the transmitting station, as illustrated in Fig. 3, the disk or other rotatable element I de?nite point when said element is in synchro nism, a stationary light source at said de?nite point and in cooperation with said transparent segments, means for illuminating said light source, electrical means actuated by said image 10 varied current for illuminating said light source only during the'period of interruption of said would be provided with a contact segment RI image varied current and a pair of photoelectric consisting of a circle‘ which would be broken at cells on the side of said rotatable element oppo- I 15 a point corresponding to the opaque or insulat- " site said light source, each of said cells being 15 ing segment in the various ?gures. It would be ’ adapted to be energized by the light of said source' similar to the path “:1” of Figure 1. A collector ring R2 of any type would also form part of the rotating element and be connected to the 20 segment by conductor C3. The broadcasting current would be supplied to the contact segment by brush b2 and taken from the collector ring by brush bi. This would produce the desired interruption. In Figure 8, contact strip 1/ and associated brushes may cause a light to be illuminated in stead of the indicator I5 and I9. Moreover, this light may have a specially signi?cant, color. The relay R covers any known means ‘of in terrupting current. Having described my invention, I claim as new and desire to secure by Letters Patent: 1. In combination: means including a rotat able element for reproducing a television image 35 from an image varied current, a pair of trans parent segments on said rotatable element the width of said transparent segments being pro gressively increased in order to increase their asynchronism correcting function, an opaque 40 when said transparent segments permit the light of said source to reach its specific cell and a speed adjusting means in cooperative relation with said cells and said rotatable element whereby 20 synchronism is maintained. 4. In combinationf a rotatable element, means in cooperative relation with said rotatable ele ment for reproducing an image from an image varied current, the diiferent portions of the sur face of said rotatable element being rotatable at di?erent uniform speeds, a variable position rotatabladriving means in cooperative relation with said rotatable element making driving con tact with any of said portions of said surface to drive said element at any desired uniform speed and photoelectric means in cooperative relation with said rotatable element and said variable position rotatable driving means said photoelec tric means including light influencing means borne on said rotatable element and a stationary photoelectric element in cooperation therewith by means of which the position of said driving means is varied in order that speed of said ro segment separating said transparent segments, tatable element is adjusted to attain synchro a stationary light source in cooperative relation nism and isochronism. with said transparent segments and said opaque segment and means connected with said light source for illuminating said light source only 45 during a portion of the revolutionary period of said rotatable element and vwhen said opaque segment is opposite to and obscuring said light 5. In combination: .40 means including a ro tatable element for reproducing an image from an image varied ‘current, the different portions of the surface of said rotatable element being rotatable at different uniform speeds, a variable position rotatable driving means in cooperative segment separating said transparent segments, a stationary light source in cooperative relation with said transparent segments and said opaque relation with said rotatable element, making ‘driving contact with any of said portions of said surface, mechanical means for varying the posi tion of contact of said rotatable driving means, a pair of transparent segments on said rotatable element, an opaque segment separating said transparent segments on said rotatable element, a stationary light source in cooperative relation with said transparent segments, said light source being adapted to be illuminated only during a short period of each revolution of said rotatable segment and means connected with said light element, a pair of photoelectric cells on the op- ' source when said rotatable element is in syn chronism, said light source being when illumi 50 nated opposite to‘ either of said transparent seg ments during asynchronism. ' 2. In combinationigeans including a rotatable element for reproduii'ing a television image from an image varied current, a pair of transparent segments on said rotatable element, an opaque 60 source for illuminating said light source only during a portion of the revolutionary period of said rotatable element and when said opaque segment is opposite to and obscuring said light source when said rotatable element is in syn 65 chronlsm, or when either of said transparent segments are opposite said light source when said rotatable element is in asynchronism and a pair of photoelectric cells, each of said cells be ing in cooperative relation with one only of said 70 transparent segments to be in?uenced by the light of either of said transparent segments dur-' ing asynchronism' of said rotatable element said cells being connected to synchronizing apparatus. 3. A synchronism indicating apparatus consist 75 ing of means including a.yrotatable element for posite side of said rotatable element to and in cooperative relation with said light source to be 60 operated by the light from said source and elec-‘ tromagnetic means in cooperative relation with said mechanical means for ‘varying the position of said variable position rotatable driving means and electrically connected to and under the con trol of said photoelectric cells to adjust the speed of said rotatable element in order to maintain synchronism and isochronism. 6. In combination: means including a rotat able element for reproducing an image from an image varied current, the'dii’ferent portions of the surface of said rotatable element being rotatable at different uniform speeds, electrical contact means carried on said rotatable element, i 2,125,991 , 9 during a fraction of. each revolution of said ro means including a rotatable driving member mak ing driving contact with one of said portions of tatable element, means including a secondm said surface at a time for imparting synchronous ' tatable element for converting said image varied and isochronous motion speed to said rotatable current intov an-image, synchronizing means in element, suitable electrical circuits including a cooperative relation with said second rotatable stationary'brush in cooperative relation with said element and operated by separate energy, means electrical contact means for producing corrective associated with said second rotatable element for holding open a synchronizing circuit by means synchronizing currents when said rotatable ele ment‘is not rotating synchronously, means ‘in of and during the ?ow'of said image varied cur rent and ‘means for closing said synchronizing 10 cooperative relation with said means for pro circuit during said interruptions. ‘‘ ' ducing, corrective currents and with said ro 11. A television apparatus consisting of a‘ ro-‘ -tatable driving member for changing the posi 10’ tion of said variable position rotatable driving tatable element, means for rotating said rotat member, and a centrifugal speed governing ele ment in cooperative relation with said rotatable able element, a pair of current in?uencing s'eg-v ‘ ments borne on said rotatable element, a non'-‘ 15 driving means in order to correct speed irreg ularities of said. rotatable driving member. 7. :A synchronism indicating‘means consisting in cooperative relation with said current in?u- . of means including‘ a rotatable element for re- ' encing segments and said means for rotating said an‘image from an image varied cur 20' ‘producing rent, an electrical contact strip placed at a syn in?uencing segment‘ separating said segments and stationary synchronism controlling means rotatable element, said nonin?uencing segment being disposed opposite said stationary synchro-‘ 20 chronisr'n indicating point on said disk, electrical nism- controlling means when a synchronizing means in‘ cooperative relation with said strip‘ current is received while said rotatable’ielement' for transmitting a periodic current received from rotates synchronously in order that said cur- , rent influencing segments may be prevented from 25 25 a distant station through said contact strip when said rotatable'elen'ient is in synchronism' and a in?uencing said stationary synchronism_ 'con synchronism indicating means in cooperative trolling means when said rotatable element relation with said electrical means which is ac rotates in synchronism. » ( 12. A television apparatus consisting of, means is in contact with said electrical means when including a rotatable element for/reproducing an 30 image from an image-modulated electric current, said current is transmitted. , the di?erent portionsfof the surface of said ro 8. A television synchronizing apparatus ‘con sisting ‘of means including a rotatable element, tatable clement moving at di?erent uniform for reproducing an image froml an image varied speeds, contact means borne on said rotatable current, the di?’erent portions of the surface of element including a pair of arcuate contact seg 35 tuated by said current when said contact strip as said element being rotatable at di?erent' uni form speeds, a variable position friction drive in cooperative relation with said rotatable element and matting driving contact/With any of said por 40 tions of said surface to impart uniform speed‘ thereto, a centrifugal speed governor in cooper ative relation with said variable position friction ments, an insulating interval separating said arcuate contact segments, stationary contact means including a brush normally in position on said insulating interval when said rotatable ele merit rotates in synchronism, a pair of electro ' magnetic-mechanical means for'operating said magnetic elements, means for furnishing a periodic synchronizing current operativeiy con~ nected to said brush and to said pair of elec-' tromagnetic elements, a variable position Ero-. tatable driving means making driving contactv variable position drive and electrical contact ele with any one of said ‘portions of said surface of drive ‘to vary the position of ' said friction drive ‘ to correct speed irregularities therein, electroments carried on said rotatable element in elec trical cooperation with said electomagnctic-me .chanicai means for operating said variable posi~ tion drive, in order to maintain said rotatable 50 element in synchronism by speed adjustment. said rotatable-element at a time and a clutch in cooperative relation with and operated by said pair of electromagnetic elements and connected with said variable position rotatable driving means in order to shift said “driving means to so engage any one of the said di?erent portions of ‘ tatable element for reproducing an image from ' said surface to cause said rotatable element to 9. In combination: means including a re an image varied current, the different portions of the surface of vsaid element being rotatable rotatev in synchronism. ‘it. a television apparatus consisting of means including a rotatable elementfor reproducing an 55 at different uniform speeds, speed 'control'elec trical contact elements carried onsaid rotatable image from an image modulated current, the element, electromagneticemechanical means in different portions of a. surface of said rotatable cooperative relation with and under control of said'speed control contact elements, a variable position friction drive in cooperative relation with said electromagnetic-mechanical means to vary the position of said variable position ro element being rotatable at, diderent uniform tatable drive, said drive making driving contact with any of said portions of said surface, a motor 65 controlling means in cooperative relation-with said eiectromagnetic-mechanical means for varying the speed of said motor and a centrifugal spccd governor in cooperative relation with said variable position drive to correct irregularities‘ "Ill in the speed of said rotatable element. . . iii, A television synchronizing system consist ing of means including a rotatable element for transmitting an image varied current, means as sociated with said rotatableelement for inter rupting said image varied current periodically speeds, a rotatable driving means in cooperative relation with said rotatable element and mamng driving contact with anyof said portions of said _ ' surface at a time, electrical contact means borne von said rotatable element including two contact segments, an insulating interval disposed be tween said, segments, a stationary contact brush normally making contact with said insulating interval when said rotatable element rotates in synchronism, shifting means for shifting the po sition of said rotatable driving means to attain and maintain said rotatable element in synchro nism and 'means for operating said shifting means in cooperative relation therewith and elec tricaliy connected to said electrical contact means and said stationary contact brush in or- vb 1O 2,125,991 der to cause said rotatable element» to rotate surface of which move at different uniform synchronously. speeds, said rotatable driving element making 14. A television apparatus consisting of means including a rotatable element for reproducing an image from an image-modulated current, the different portions of a surface of said rotatable element being rotatable at different uniform speeds, a rotatable driving means in cooperative relation with said rotatable element and making ,10 driving contact with any of said portions of said surface at a time, electrical contact means borne on said rotatable element including two contact segments, an insulating interval- disposed between driving contact with any of said di?'erent por tions of said surface at a time, a centrifugal speed governor in cooperative relation with said second shaft and acting to cause said shaft to enter more or less deeply in said hollow of said hollow shaft to move said rotatable driving element to contactv with different portions of‘said surface to correct speed irregularities therein, a clutch 10 for shifting said rotatable driving element into contact with any of said portions of said surface, electromagnetic means for operating said clutch said segments, a stationary brush in cooperative - and suitable electrical switching means 'in co relation with said segments and said insulating » operative relation with said rotatable scanning 1,5 element and connected by suitable circuits to said electromagnetic means to operate said clutch contact rings borne on said electrical rotatable in accordance with speed ‘variations in said ro element and connected to said contact segments, tatable scanning element. 18. An automatic television synchronizing ap 20 a pair of stationary brushes making contact with .c paratus consisting of means including a rotatable said contact rings, a ‘clutch engaging said rotat able- driving means to bring said driving means in scanning element for forming an image from an image-modulated current, means for rotating‘ contact with said different portions of said sur face, electromagnetic means in cooperative rela said rotatable element at uniform speed, syn tion with and operating said clutch and connected chronizing means for maintaining said rotatable 25 element in synchronism, a switch connected to by suitable circuits to and controlled by said con tact segments said electrical contact brushes and and controlling said synchronizing means in order said contact rings in order to maintain said to out said synchronizing means in or out of rotatable element in synchronism. circuit and a speed governing means in coopera 15. A television apparatus consisting of means tive relation with said switch to bring said syn 30 30 including a rotatable element for forming an chronizing means into action when said rotatable image from an image modulated electric current,’ element rotates at approximately synchronous interval, said brush being situated on said insu lating interval during synchronism, two electrical means for uniformly rotating said rotatable ele ment, synchronizing means including suitable C12 Cl electrical circuits and a controlling switch for operating said means for uniformly rotating said rotatable element at synchronous speed and a speed governing means operatively connected to said controlling switch to close said switch and 40 circuits when said rotatable element is rotated ‘at approximately synchronous speed. 16. An automatic television synchronizing ap paratus consisting of a motor, a longitudinally shiftable shaft rotated by said motor, a rotatable driving element slidably mounted upon said shaft and being unrotatable relatively therewith, a ro speed. 19. An automatic television synchronizing ap paratus consisting of means including a rotatable 85 scanning element for forming an image from an image-modulated current, a rotatable driving ele ment slidably mounted upon a shaft and making driving contact with the surface of said rotatable scanning element, the different portions of the surface of said scanning element being rotatable at different uniform speeds and said driving ele ment making driving contact with any of said portions of said surface at a time, a clutch for shifting the position of said driving element to 45 bring it into contact with any of said portions, tatable scanning element, the different portions electromagnetic means for operating said clutch, ' of a surface of said scanning element being mov» able at different uniform speeds, said rotatable suitable switching means in cooperative relation with said rotatable scanning element'and con 50 driving element making driving contact with any nected by suitable circuits to said electromagnetic ~ a time, a centrifugal speed governor'in coopera speed irregularities in the motion of said rotatable one of said different portions of said surface at tive relation with said shaft in order to longi~ tudinally shift said shaft in accordance with speed variations to bring said rotatable driving ' . 20. An automatic television synchronizing ap paratus consisting of a uniformly rotatable driv 55 ing means, a. centrifugal speed governor in co gaging with and acting to shift said rotatable operative relation with said driving means, to correct speed irregularities therein, a variable position rotatable contact element in cooperative relation with and driven by said driving means, 60 electromagnetic means operating said clutch and suitable electrical switching means in coopera tive relation with said rotatable scanning element and connected by suitable circuits to said elec tromagnetic means to operate said clutch in 'ac cordance with speed variations occurring in said 65 scanning element. element into new driving positions, a clutch en driving element 'to different drivlng' positions, 60 means to operate said clutch in accordance with rotatable scanning element. ' - ‘ 1'7. An automatic television synchronizing ap paratus consisting of a motor a hollow shaft rotatable by said motor, a second shaft in co operative relation with said hollow shaft and 70 making slidable engagement in the hollow of said hollow shaft, said shafts being relatively unrotat able with each other, a rotatable driving element slidably mounted upon said second shaft and being unrotatable relatively thereto, a rotatable 75 scanning element the different portions of 9. means for shifting the‘ position of said variable position rotatable contact element to impart dif ferent desired uniform speeds to said rotatable contact element, means including a rotatable scanning element for reproducing an image from 65 an image modulated current, the different por tions of a surface of said scanning element being rotatable at different uniform speeds and being in cooperative relation with said variable posi tion contact element, electrical means including suitable contacts borne on said rotatable scanning element in cooperative relation with said means for shifting and a switch in cooperative relation with and controlling said electrical means andlin cooperative relation with and to‘ be operated by aiaqaoi 11 said centrifugal speed governor close said ‘switch when said rotatable scannlngelement ro operative relation with a stationary light source tates at approximately synchronous speed. 24. A- claim in accordance with claim 21 but in which said means for producing corrective syn 21. In combination: a ‘rotatable element, means in cooperative relation with said rotatable element for reproducing an image from an image - varied current, the different portions of the sur- > face of said rotatable element being rotatable at different uniform speeds, a variable position ro 10 'tatable ‘driving means in cooperative relation with and photoelectric cells. ' chronizing adjustments includes transparent por- , tions borne on said rotatable element and sta- tionary photoelectric cells in cooperative rela-. tion with electromagnetic means. a 25. In combinationz'a rotatable element, means in cooperative relation with said’ rotatable ele 10 said rotatable element making driving contact ment for reproducing an imageiirom an image with any of said portions of said surface to drive varied current, the diilerent portions or the sur- ' said element at any uniform speed and means for ‘ face of said rotatable element being rotatable at producing corrective synchronizing adjustments 15 in the position of said variable position rotatable driving means in cooperative relation with said rotatable element and said variable position ro tatable ‘driving means where said rotatable ele ment is not rotating synchronously. 22. A claim in accordance with claim 21 but in which said means for producing corrective syn chronizing adjustments includes transparent por di?erent uniform speeds, a variable position ro tatable driving means in cooperative relation with 16 said rotatable element making driving contact ~ with any of said portions of said surface to drive said element at any'uniiorm speed and means for producing corrective synchronizing currents when said rotatable element is not rotating syn chronously, and means in cooperative relation with said means for producing corrective currents 23. A claim in accordance with claim 21 but in which said means for'producing corrective and with said variable position rotatable driving means to re-establish synchronism by‘ changing the position of said variable position rotatable synchronizing adjustments includes transparent driving meana, tions on said rotatable element. _ r portions borne on said rotatable element-in co - . ‘ \iAI-OYSIUS J. CAWLEY.