US1908809A - Scanning apparatus for television - Google Patents

Description

y 1933- H. s. BAIRD SCANNING APPARATUS FOR TELEVISION Filed Nov. 15, 1929 2 Sheets-Sheet l uup uunnunuunuuuuuuu UIJDUHDUEIUDUDUUDDUU fhverziof. H-M & a l-S May 16, I933. Hv BA|RD 1,908,809

SCANNING APPARATUS FOR TELEVISION Filed Nov. 15, 1929 2 Sheets-Sheet 2 A26 /2 8 w a Patented May 16, 1933 uNiTEo s ms HOLLIS s. BAIBD, or. ST NEHAM; 'ivm'sseoriusnrrs, ASSIGNOR, T0 snon'rwnvnfia TELEVISION CORPORATION, DELAWARE or nes roir MassAeHUsErr'syAff coitroim'rion 0F scienivme ArrAaA'rUsronfmiinnyisioiv Applicationlfiled November 15, 1929. Serial madame; I f

This invention relates to television and particularly to receiving apparatus therefor having picture re-constituting apparatus which includes a scanning device provided with 5 small and suitably arrange-d windows which rotate in front of a light emitting source, the intensity of illumination of which is caused to be varied by the transmitted picture sig nal. I i

In my cop-ending application Serial No. 366,974, filed May 29, 1929,.1 have disclosed a scanning device which consists of an opaque endless belt having scanning windows therein and arranged'to be driven in synchronism with the scanning device at the transmitting station. The belt preferably is an endless section of a moving picture film and the scanning windows are photographed thereon, the sensitive photographic film beingexposed to astrong illumination except at the location of the windows so that when the film issubsequently developed and fixed, the film is opaque except at the windows, where. itis transparent. Y

One of the objects of the present invention is to provide supporting and driving mechanism for such scanning belt that is relatively free from noise when in operation, has few operating parts, and lendsitself readily for enclosure within a cabinet which can also contain the signal detecting and amplifying apparatus essential to the television apparatus.

Another object of the invention is the provision of a supporting and driving mechanism 35 for the belt, which mechanism includes a'scan ning drum on the periphery of which the scanning belt is supported, .the drum being perforated, or having openings, ,at the windows and having imperforate peripheral portions that are located between and beyond the windows. a

The drum is driven by a synchronous. motor which has a weak starting torque Consequently, it is an object of the invention to provide means by which the motor .canbe started in rotation independently of the drum thereby to reduce the load on the motor at the moment of starting. Specifically, thisobj-ect of the invention comprehenfds a lost-motion connection between the armature of the mo- .tor and the: drum so .that the 'motor canlbegin to rotate. prior to itsengaging and rotating thedrum. .,f

.Television'signals at present are broadcast .by'radio by means of scanning-apparatus op .erate'dat various; speeds and havinga variable number of scanningwindows; Consequently, .a scanning-belt operated at Ya certain speed and having a certain 'number, of scanning windows, and adaptedfor one particular system ofscanning signals cannot ,receive intel- 'ligible signals producedby 'a difierently arranged and operated scanning device. Consequently,another .object of this invention is to provide-arotatable drum that-is adapted to support scanning belts having diiferent .nu'mbersof windows, which; also' may be differently located, on the belt, combined with 111834115 to rOtatethe drum at; various; selected speeds whereby. the device can be adjusted to receive difi'erenttypes of broadcast [tele- -.vis1on sig'nals. I

While the broadcast aijid receiving stations may operate in%syn'chronism they yet may be displaced inphas'e,fo'r-Zout of step,;so that thereceivedfl picture is out of frame. Itis an obj ect. ofthe present invention to provide a; simple means? for: -bri-nging; the received .wh'ichfis provi'ded'with' scanning windows, 7

viewing frame located Withouttheperiphery of the drum, and a variable light source located :within theperiphery of; the drum.

A furtherfobjectis generallyto improve the construction and operation of television apparatus."-.' f; pf j Fig. '1 is a front elevation of the'cabinet enclosing the apparatuse'mbodyingthe present invention and, in.itself,;- constituting, a part ofthein-ventionr A r f Fig- 2 is a sectional elevation through the cabinet of- Fig. 1 and. illustrating in detail the construction 1 of the app aratustherein, parts of the apparatus not essential to, the present invention being omitted. Fig. ,3 is a fr'ontelevati'on of the scanning drum of.Fig-.2 :F-g V1 Fig. 4 is a plan detail of the ap aratus of Fig. 2, parts of the drum being bro en away.

Fig. 5 is a plan view of a section of the scanning belt associated with the present invention.

'Fig. 6 is a sectional deteJiL-taksn along line 6-6 of Fig. 2 and illustrates especially the gaseous-conductor lamp and its supporting means i 1 I The apparatus embodying the presentinvention is contained within the enclosing cabinet 10 having a front wall 12 and atop wall 14 which is hinged at 16 to the rear wall 18, the top wall thus constituting a cover which can be raised to gain access to themeGhanism within the cabinet. The movable elements of the television apparatus are supported upon a base 20 which is carried by the bottom wall 22 of the cabinet. Vertical and peripherally spaced standards 24 upstand from said base and support an intermediate. plate 26 and, spaced thereabove, an upper plate 28. A vertical shaft 30 is journalled in bearings 32 in said plates and has an enlarged annular flange 34 which overlies the upper plate and also has an end 36 which shaft although the drum can be removed at will from the shaft, both being free from anyposi-tive attachingmeans. The flange 34 of the shaft is "provided with an upstanding driving pin -46 which is received within a peripherally elongated groove 48, see Fig. 4,

so that the shaft can have a small amount of initial rotary movement before the pin engages a wall of the groove to drive the drum. With this arrangement, the synchronous driving motor, presently to be described, for the drum can start to rotate freely before it takes on the load of the drum. The hub of the drum is seated on the flange '34 and has suliicient frictional engagement therewith to prevent hunting of the drum, or its alternate engagement and disengagement the pin 46 when the drum and shaft are running at synchronous speed. The drum is provided with upper and lower peripheral- 1y continuous portions '50 and 52 respectively which are connected by vertical ribs 54 located within the drum. The periphery of the drum is provided with'a continuous outstanding flange or head 56 located at the lower portion of the drum and which con stitutes a stop member that is engaged by the lower edge of the scanning belt to define its operative position on the drum. The

outer face of the periphery above the bead outer diameter of the drum so that when the belt is on the drum it is a snug, although readily detachable, fit thereon. The belt has 7 such width that its upper and lower marginal portions overlie the upperand lower peripherally continuous portionsand 52 of the drum. The body of the scanning belt is opaque except at the scanning windows 60, thereim'see Fig. 5, which windows are preferably, although not necessarily, square and are of small area and are spacedlengthwise along the belt and also are spaced in a progressive manner transversely of the belt. The number of scanning windows and their spacing lengthwise of the belt is dependent upon the particular system on which any particular television signal is broadcast and belts having different numbers of scanning windows, which may be difierently spaced along the length of the belt, are adapted to be interchangeably supported on the drum to condition the apparatusto receive television signals broadcast under different systems. As specifically described in'my above referred to application, thescanning belt herein shown consists of a section ofphotographic and particularly moving picture film wherein the windows are photographically developed. I

- The driving mechanism for'the' disc includes a synchronous motor 62, the shaft 64 of the rotatable armature of which'is vertically disposed and is rotatable in bearings 66 of the upper and intermediate plates 28 and "26, respectively. The motor is secured to a supporting plate 68 whichhas upstanding arms 70 between which the lower portion of the'field frame of the motor is located and to which arms it is'secur'ed. Said plate is rotatably supported upon the upper face of an upstanding peripheral flange 72 carried 'by the base plate 20 and has a stud shaft 74 which is rotatable in a bearing 76 of said base plate. Said plate 68 is pr'ovided with gear teeth 78 on its lower face which mesh with a pinion gear 80 fixed to a shaft 582 which is journalled in the base plate2O and extends through the front wall 12' of the cabinet'and terminates thereat in a knob 84. When the received pictures are out of frame they can be brought into frame by rotating.

theshaft 82 and consequently the field frame of the'motor 62 a suitable amount. This changes'the phase relation of the-received, picture with respect to the transmitting pic- 86 and a large gear 88 are fixed in superposed relation on the drum shaft between the intermediate and upper plates 26 and 28. The motor shaft 64 is provided with a driving gear 90 having a driving face the width of which is equal to the combined width of the driving faces of the two gears 86 and 88. A speed-changing frame 92 is pivotally supported on a shaft 96 carried by the intermediate and upper frames and has two arms 94 and 95, see especially Fig. 4, which are located on opposite sides of the driving gear. Idler gears 98 and 100, which preferably are identical, are pivoted to the ends of said arms. When the frame 92 is moved in a counterclockwise direction, Fig. 4, the gear 100 is thereby disposed in mesh with the driving gear 90 and the small gear 86 ofthe drum shaft whereby to establish a high speed driving connection between the motor and drum. \Vhen the gear frame is swung in a clockwise direction, the gear 100is adapted to be moved out of mesh with itscooperatgears and the gear 98 isadapted to ';be moved into mesh with the driving gear 90, and the large gear 88 on the drum shaft. A low speed driving connection is thus established between the motor and drum.

The gear frame 92 isprovided with an arm 102 which is loosely extended througha horizontally elongated slot in a plate 104 carried by the intermediate plate 26. -A knob 106, the outer portion of which isin front of the front wall 12 of the cabinet, is horizontally movable in a slot 108 therein and is siidable on said arm 102 under urge of a spring 107 thereon and has a reduced end 110 which can enter a series of apertures 112 in said plate 104 to lock the gear frame 92 with either one of its idler gears in'mesh with the driving and driven gear. It can also lock said frame in an intermediate position wherein the drum andmotor are. free from a driving connection therebetween.

The front wall 12 of the cabinet is provided with viewing frame or tube 114 the inner end of which has a preferably square opening which confronts the belt on the drum and in the outer end of wh ch is an enlarging lens 116 located whereby an enlarged image of the received picture can be viewed. A variable source of illumination 118', as a gaseous conductor, or neon lamp, is located within the drum in radial line with the scanning belt and lens 116 and has a pair of electrodes 120 and 122 of which the electrode120 confronts the belt and lens and constitutes the variable source of illumination. Thelamp is carried by a bracket 124 which issl-idable on a pair ofspaced rods 126- that overlie the top ofthe drum and are secured in'brackets 128 carried bythe-cover 14 of the cabinet. A condensing 16118111111, 130 is also slidably carried bysaid rods and is interposed between windows of thescanning belt and serves-to concentrate the light of the lamp on the windows. As thus arranged,'when the cover 14 is raised thelamp and lens are automatically removed from operative position within the scanning drum so that the drum can be removed for the purpose of applying different scanningbelts thereon.

The mechanism here shown is simple, ef fective and reliable. It is freefrom electrical disturbances which would effect the radio receiving and amplifying apparatus associated with the neon lamp and consequently said apparatus can be located in the cabinet herein shown in close'proximity to the mo.- tor and its associated apparatus and tuned to any desired incoming signal by the tuning device 132. Since the receiving and amplifying .apparatusforms no part of the present invention, it is omitted from the present illustrations.

Iclaim: 1

1. A scanning device for televisionincluding an annular rotatable member having peripherally located alternate supporting surfaces and openings therein and a-scanning member separate from and supported and carried bysaid rotatable member upon said surfaces and extended over said openings and having scanning windows which are located in register with said openings.

2. A scanning device for television includinga rotatable drum having a cylindrical periphery provided with openings therein, and an endless scanning band carried removably by and disposed against said cylindrical periphery and overlying said openings and havingv scanning windows which are located at said openings. I

3. A scanning device for television including a rotatable drum having a cylindrical'periphery provided with openings therein and a peripheral flange that outstands beyond said periphery and is located belowsaid openings, and an endless fiexiblescanning belt carried removably by and disposed against said cylindrical periphery over said openings having one edge thereof seated upon said flange and having scanning windows therein which are located at said openings.

4. A scanning device for television including a rotatable drum having a driving hub provided with outstanding driving connected with and upstands above said 7 against deformation by said cylindrlcal peczi posed windows therein.

riphery.

5. A scanning device for television including a rotatable drum having a driving hub provided with outstanding driving arms, and a cylindrical periphery which is connected with and upstands above said arms and hubs and has openings therein, and an endless flexible scanning belt supported against'flexing by and seated upon said cy- 'lindrical periphery over said openings and having windows which are located at said openings. 6. Ascanning device for television including a rotatable drum having lightvpassages and an endless flexible scanning beltcarriecl remova'bly by said druinand'havingex- 7. Scanning apparatus fortelevision including a horizontally rotatable scanning device having a hub, a vertical drivingshaft for said device loosely located in said hub andhaving an outstanding flange on which said hub is frictionally seated, and a lostmotion positive driving connection between said shaft and scanning device including a pin carried by said flange and located in an arcuate slot in said hub. 8. Scanning apparatus for television including a horizontal rotatable scanning device, and means to adapt said scanning device to receive'signals transmitted under dif- :ferent systems including afdrive shaft for said device, a plurality of gears of ,diflerent' diameters fixed thereon under said scanning dru1n,'a vertical motor-located beneath said scanning device/having an upstanding shaft provided with a driving gear,'speed-changing mechanism located between and connecting 'said motor and scanning device including a movable frame having arms which are disposed on opposite sides of said aforesaid gears and have idler gears thereon, and means to move said frame in opposite directions to bring both idler gears separately into mesh with said driving gear and a sep-- arate one of said other gears.

9.Scanning apparatus for television including a rotatable scanning device, and means to adapt said scanning device to receive signals transmitted under different systems including a drive shaft for said device, a plurality of gears of diflerent diameters fixed thereon, a supporting frame under said scanning device in which said shaft is j ournaled, a motor under said frame having a vertical shaft provided with a driving gearfarranged in horizontal line with the aforesaidgears, speed-changing mechanism connecting said motor and scanning device including-a movable frame pivoted on said supportedframe and having arms which are positions, and also in an intermediate position wherein all of its idler gears are free from driving connection with the aforesaid gears.

10.Scanning apparatus for television including a vertical driving motor having a rotatable armature and a stationary field frame, a scanning device havinga support on which it is rotatable, means providing a speed-reducing 7 driving connection between said armature and scanning device, and means to vary the framing of the received picture including means to angularly shift the position of said field frame, the speedreducing' driving connection providing a small angular displacement of said scanning device for a large angular displacement of said field frame, said last mentioned means comprising an annular gear attached to the 'end of said field frame.

11. Scanning apparatus for television in cluding a supporting base, a horizontal plate rotatable on said base, a vertical motor having a rotary armature and a stationary field frame which latter is supported by and is fixed to said rotary plate, a scanning device having a rotatable support on said base above said motor, means providing a driving connection between said scanning device and motor, and means to vary'the framing of the received picture including means to rotate said motor supportingplate on said base, said plate and said base having frictionally engaging surfaces which hold said plate and motor field frame against any rotary movement caused by the driving reaction between said field frame and motor armature.

12. Scanning apparatus for television including a base, standards rising thereabove, vertically spaced intermediate and upper plates carried by said standards, a vertical shaft journalled in said plates, a horizontally rotatable scanning drum carried by said shaft above said upper plate and having a removable driving connection therewith, a vertical motor located between said standards and mainly below said intermediate plate having a driving shaft extended into the space between said plates, a gear fixed to said shaft, a second gear fixed to said shaft of said scanning drum, means establishing a driving connection between said aforesaid gears, a plate rotatable on said base providing a support for the field frame of said motor,'and means to vary the framing of the received picture including means to rotate said plate and consequently said motor frame.

13. Scanning apparatus for television ineluding a base, standards rising thereabove, vertically spaced intermediate and upper plates carried by said standards, a vertical shaft journalled in said plates, a horizontally rotatable scanning drum carried by said shaft above said upper plate and having a removable driving connection therewith, a vertical motor located between said standards and mainly below said intermediate plate having a driving shaft extended into the space between said plates, a gear fixed to said shaft, a second gear fixed tosaid shaft of said scanning drum, means establishing a driving connection between said aforesaid gears including a gear frame pivotally located between said intermediate and upper plates and pivotally supported by at least one of said plates having a gear which is movable by movements of said frame into mesh with both aforesaid gears, a plate rotatable on said base providing a support for the field frame of said motor, and means to vary the framing of the received picture including means to rotate said plate and consequently said motor frame.

14. Television apparatus including a rotatable scanning drum having a cylindrical periphery provided with scanning windows, a viewing frame located exteriorly of said cylindrical periphery, a variable light source located within said cylindrical periphery and stationarily-supported means constituting a track which is perpendicular to said cylindrical periphery and to said viewing frame and on which said variable light source is guided for movements toward and away from said viewing frame.

15. Television apparatus including a rotatable scanning drum having a cylindrical periphery provided with scanning windows, a viewing frame located exteriorly of said cylindrical periphery, a variable light source located within said cylindrical periphery, a condensing lens located between said periphery and variable light source, and supporting means for said lens and variable light source constituting a track which is perpendicular to said cylindrical periphery and to said viewing frame on which both are independently movable in the same line toward and away from said viewing frame.

16. Television apparatus including an enclosing cabinet having a fixed viewing frame and a removable cover, scanning mechanism includinga rotatable scanning device which is located under said cover and has a removable windowed scanning member, and a variable light source carried by said cover on the side of said scanning device opposite said viewing frame, said variable light source be ing automatically removable from its aforesaid position when said cover is removed from closing relation with the cabinet so that said removable scanning member is accessible for instant removal.

17 Television apparatus including an enclosing casing having an open top and a cover removably closing said top, a viewing frame located in a side wall of said cabinet beneath said top, scanning apparatus located within said cabinet including a horizontally disposed rotatable scanning drum having on and removably connected with its periphery a scanning band provided with scanning windows and located immediately under said cover in

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