US2295572A - Duplex facsimile transceiver - Google Patents

Description

p 15, 1942- w. G. H. FINCH 2,295,572

DUPLEX FACSIMILE TRANSCEIVER Filed Feb. 10, 1940 8 Sheets- Sheet l ATTORNEYS P 1942- v w. G. H. FlNCH DUPLEX FACSIMILE TRAN SCEIvER Filed Feb. 10, 1940 8 Sheets-Sheet 2 INVENTOR. William gfl inch @Mr M A TTORNEYS p 1942. w. G. H. FINCH 2,295,572

DUPLEX FACSIMILE TRANSCEIVER Filed Feb. 10, 1940 8 Sheets-Sheet I5 INVENTOR. williamg.% inch Me M ATTORNEYS P l942- w. a. H. FINCH 2,295,5 72

DUPLEX FACSIMILE TRANSCEIVER Filed Feb. 10, 1940- 8. Sheets-Sheet 4 FIG.4.

1 N VEN TOR. Willi a m 5.]iji11ch ATTORNEYS p 1942- w. s. H. FINCH 2,295,572

DUPLEX PACSIIILE TRANSCEIVER Filed Feb. 10, 1940 8 Sheets-Sheet 5 INVENTOR.

William gdtfl'nch BY MM M ATTORNEYS Q ll. 1

Sept. 15, 1942. I w. s. H. FINCH DUPLEX FACSIHILE TRANSCEIVER Filed Feb. 10, 1940 8 Sheets-Sheet 6 I if I!!!IIIIlI/llll'lll'llllllllllllllIlrllfflIllIt'll/IIII!II!lfffll/llI/IlllllllllflI! h i L m sum Mam m III/II/I/I/I INVENTOR. William yfl n 'lncll BY MM p M ATTORNEY 8 Sept. 15, 1942. w. s. H. FINCH 2,295,572

DUPLEX FACSIMILE TRANSCEIVER Filed Feb. 10, 1940 8 Sheets-Sheet 7 FIGLI.

.117 M g i INVENTCRT William 9,15,5'7510/1 ATTORNEYS p 15, 1942- w. G. H. FINCH 2,295,572

DUPLEX FACSIMILE TRANSCEIVER Filed Feb. 10, 1940 8 Sheets-Sheet 8 INVENTOR. willie! Jffinck Mir/ ATTORNEYS Patented Sept. 15, 1942 UNITED STATES PATENT OFFICE'Z' DUPLEX FACSIMILE TRANSCEIVER William G. H. Finch, Newtown, Conn. Application February 10, 1940, Serial No. 318,230

' 8 Claims.

This inventionrelates to novel apparatus for and methods of transmitting and receiving signals and more particularly relates to novel ap- Daratus for and methods of visual broadcastin and reception.

This specific invention is concerned with the combination in a single,-light-weight unitary simplified mechanism of both the facsimil transmission and receiving apparatus. The duplex device thereby formed is arranged so that the' more important portions of the operating mechanism are therefore utilized both for transmission and reception of facsimile'signals and forthe operation of the various mechanical portions thereof, thus resulting-in an appreciable means.

By the use of this simplified duplex device, therefore, instructions or other information may be transmitted visually-that is, necessary charts and other information best transmitted by visual means may readily be received by the operator of the airplane and likewise, any re- Ports best embodied in visual form may be transmitted by the operator station.

Thus, for instance, where in military operations, reconnaissance flights must be made to points far removed from the main base, wherein the return trip may take several hours, it may be extremely important that the pilot or observer be able to transmit charts or other visual reports immediately after the making of the same so that any possible information obtained in such a flight might not be lost, owing to difficulties during the return.

Likewise, the transmission of a chart or furor pilot to the central ther visual instruction to a pilotfar removed from his main base may best be facilitated by the use of facsimile equipment of the type herein described. 7

One of the essential elements of the present invention therefore is the embodiment in a simplifled unitary light-weight mechanism of facsimile transmitting and receiving media. I

Still another essential object and purpose of the present invention is the utilization of the same mechanism and apparatus to operate both the facsimile transmitting and receiving media.

Another object of the present invention is the arrangement of the elements and parts of the duplex facsimile transceiver so that the operation thereof will essentially be automatic.

' Still another object of the present invention is the arrangement of the transmitting and receiving elements of the unitary duplex member in such a way that actually no adjustment thereof is required to chang from facsimile transmission, to facsimile reception; the only important adjustment being that of changing from a receiving to a transmitting channel or means.

The present invention is primarily concerned with the actual facsimile transceiver itself and the means by which the signals generated are actually transmitted can, of course, be varied to suit the particular purpose.

Thus, for mobile units, such as automobiles, boats and airplanes, radio may furnish the best channel of transmission while for semi-portable units such as those which are to be either semi-permanently or permanently installed on land, or' those which are to be carried about by an individual, means for connecting inductively Or in any other way to telegraphic or telephonic circuit may be utilized.

In order to accomplish these primary objects of the present invention, I have found that both the receiving and transmitting drum and scanning elements thereof may be operated by the same mechanical elements without the necessity for any substantial adjustment (except for the change from a radio or electrical signal transmitting means to a receiving means).

The present invention may obviously be used not merely for transmission from a central base point to the mobile unit and the receivers but also for transmission and reception between mobile units for various purposes, the utility of which is quite obvious.

Essentially, the invention consists of the arrangement-of transmitting and receiving drums so that that may be operated from a single power source contained within a single duplex unit and the arrangement of means for transmitti-ng variations in light modulation and the means for receiving the same, also unitarily operable within a single unit and by a single mechanical apparatus. The transmitting and receiving drums are so arranged that they are readily accessible from the front or top of the unit, and the only operation actually required by the user is to place the sheet to be transmitted on the transmitting drum and the recording sheet on the receiving drum and switch his apparatus either to transmitting or receiving facilities for the purpose of operating the mechanism. Actually no further operations are required.

Many other objects anduses of the invention will in part be apparent and in part pointed out in the following description and drawings, in which:

Figure l is a view in perspective of a complete facsimile transceiver, I

Figure 2 is a top plan view of the unitary duplex unit of the present invention with the cover of Figure l removed.

Figure 3 is a cross-sectional view taken on the line 2-3 of Figure 1.

Figure 4 is another cross-sectional view taken on line 4-4 of Figure l.

FigureS is a top cross-sectional view taken on line 5-5 of Figure 3.

Figure 6 is a cross-sectional view taken on line 5-6 of Figure 3.

Figures 7, 8 and 9 are cross-sectional views taken on line 1-1 of Figure 6.

Figure 10 is a cross-sectional view taken on line ill-40 of Figure 2.

Figure 11 is a cross-sectional view taken on line II-ii of Figure 2.

Figure 12 is a cross-sectional view taken on 4 line i2-l2 of Figure 2.

Figure 13 is a cross-sectional view taken on line |3-I3 of Figure 2.

' Figure 14 is a detail view of a portion of the transmitting scanning apparatus.

Figure 15 is a detail view of the recording scanning apparatus.

Referring now to Figure 1, I have here shown my facsimile transceiver or duplex unit comprising a transmitting drum 20, a receiving drum 2i and an outer covering 22.

It will be noted that both the transmitting and receiving drums are readily accessible from the outside of the unit for immediate use by the operator thereof. The transmitting drum may readily be removed by the release of the securing means 23 hereinafter described for the purpose of wrapping a picture to be transmitted about the same, and the receiving drum 2i comprises securing means hereinafter more completely described for securely wrapping a record ing sheet about the drum 2i. As may readily be seen, it is not necessary to remove the receiving drum 2i in order to wrap a recording sheet about the same, while the transmitting drum may readily be removable for this purpose. In particular adaptations of my device it may be possible to make both the recording and transmitting drums readily removable in exactly the same manner or it may be possible to make both the transmitting and receiving drums permanently positioned in the apparatus.

Preferably, as seen in Figures 3 and 4, the apparatus comprises a cast iron base 2|, upon which the parts may be securely supported and providing sufficient stability and steadiness for the device itself to preclude the transmission of vibrations from various parts of the mechanism through the base to other parts thereof. The

size, proportions and weight of the base itself may readily be varied in view of the particular use to which the duplex device is to be put.

For mobile work in such cases where reduction of weight is an important factor and where detailed accuracy or clarity may be to some extent sacrificed to lightness in weight and ready portability, the size and weight of the base 25 may be varied accordingly.

The motor 26 is mounted on the base 25 by means of bolts 21, securely positioned in a platform 24 carried by the base 25. The motor 24 may be maintained in generally synchronous operation with the motor of the remote transmitting or receiving device by various means which are now well known in the art, such as synchronous motors, D. C. motors in combination with fly wheel, or tuning forks, the essential element being that the motor rotates at a predetermined speed which is to be maintained as closely as possible at the constant speed.

The synchronizing mechanism hereinafter described will compensate for any possible slight variations in the speed of rotation of the motor 26 with respect to the motor of the remote trans mitting or receiving device but in order effectively to operate the duplex unit, the motor should be maintained as closely as possible to the predetermined speed.

The motor 28, Figure 4, is connected by the clutch 35 to the main drive shaft 35, which drive shaft 36 projects out of the housing through the perforation 31, see Figures 1 and 4, and terminates in a handle 38. The drive shaft 36 comprises spiral gears 38 and 40 which are mounted thereon in any suitable manner and which are arranged coaxially and concentrically therewith,

Spiral gear 39 cooperates with gear 42 which is mounted on the shaft 43, which, as is seen in FigureZ, drives the transmitting drum 20. Spiral gear 40 cooperates with gear 44 mounted on the sleeve 45 which operates the receiving drum 2|. Suitable housings 48 and 49'may be placed about these spiral gear and gear connections in order to, as far as possible, dust-proof the same and also in order to provide suitable bearings at III and 5l for the shaft 43 and at 52 and 53 for the sleeve 45.

It must be noted that, as seen in Figure 5, the sleeve 45 is preferably made of insulating material for purposes hereinafter described. Suitable removable cover plates 60 and GI may be mounted on the housings 48 and 49 by means of the screws 63 and 64 to permit access to the interior thereof for repair or replacement of any portion of the spiral gear and gear combinations.

The transmitting drum shaft 43 is rotatably carried not only in bearings so and 5| but also in bearing II in the end wall II of thehousing 22 and in bearing I2 of a rise 13 of the base 25. Shaft 43 terminates at the opposite" side of the bearing I2 in a tail stock 14 and a disk I5, the disk 15 being keyed to the shaft 43. Disk I5 carries mounted thereon a pin 10 for cooperating with and driving the transmitting drum 20.

The transmitting drum 2! is preferably hollow, the drum having the general interior conformation shown in Figure 6 and comprising two ends I. and 8!, each of the ends having an indented or perforated portion 42 and 83 for cooperating with the tall stock 14 and the tail stock 00 of the securing device. The end of the drum has a perforation II for receiving the pin I6 when the transmitting drum is mounted on the device so that the transmitting drum 20 is driven by shaft 49 by means of the pin and perforation connection 19-9I between the shaft 49 and the drum 29. The opposite end 9| is releasably supported by means of the removabletail stock 99 which engages the perforation 99. The removable tail stock 99 is, as seen in Figures 1 and 5, mounted upon the swingable member 95 which is pivotally mounted on a pin '99 and retained in place upon the pin by the cap 91;

' The swingable member 95 comprises an enlarged portion 99 within which is mounted the tail stock 99. The opposite end of the swingable member 95 terminates in a bifurcated portion 99 for cooperating with the locking member I99, see Figures 1, 5 and 13. The locking member I99 comprises a link I95 rotatably mounted by means of the collar I99 on the pin I91 which is carried by a rise I99 of the main frame 25, the link I95 being maintained in predetermined position by the fact that it rides in a close fitting recess I99 in the frame portion I99. The link I95 terminates at the upper portion thereof in a washer II5 which is secured in any'suitable manner to the top of the link, as, for instance, by the screw H9. The hollow cylindrical slide member II1 having a top H9 and flanges H9 at the bottom thereof, as wellas a perforation I29 through which the link may pass, is mounted upon the mounted upon the tail stock 14 and the perforation 9| is caused to register with the pin 19, then the swingable member 95 may be moved from the position shown by the dotted lines of Figure 5 over to the position shown by the solid lines thereof. In such case then the locking device I99 may be swung up about the pin I91 and caused to engage the bifurcated end 99 of the swingable member in the manner shown in Figure 13. That is, for the purpose of locking the swingable member in place, the hollow cylindrical portion II1 may be grasped and pulled away from the mounting of the link, thus making it possible to,swing the link up to the position shown in Figure 13, and then a release of the hollow cylindrical member II1 will permit the spring I25 to drive the hollow cylindrical member downwardly in the manner hereinbefore described so that the bottom end thereof presses against the bifurcated member 99 and holds the same in place. Obviously, in this operation the link passes into the space I99 between the tines of the bifurcated end 99, and the bottom portion of the hollow cylindrical 'member II1 presses down upon the top of the bifurcated end 99. In this way, the tail stock 99 is swung into engagement with the perforation 99 at the other end of the drum and the transmitting drum is rotatably supported at-both ends.

The drive from the main shaft 99 of the motor is then completed to the transmitting drum;

" that is, the main shaft 99 through the worm. 99

in rotation of the transmitting drum in accordance with the operation of the motor. Obviously,

the transmitting drum therefore may readily be matter thereupon in the manner hereinafter link in the manner shown in Figure 13. A comdescribed.

After the drum is placed into the unitin the position in Figures 1 and 5 in the manner hereinbefore described, then the unit is ready for transmission.

The same type of connection may generally be utilized for the receiving drum so that it may readily be removable where desired, although this is not essential, it being necessary merely to provide means for securing the recording paper upon the receiving-drum without necessarily removing the receiving drum-from its mounting on theedevice. I

The receiving drum is driven through the sleeve 45, which is not directly connected to the receiving drum. Essentially, this is'done for the primary reason that the receiving drum should be mechanically isolated by means of a ,friction clutch, from the remainder of the driving mechanism for the synchronizing purposes hereinafter described.

As is seen in Figures 2 and 5 the receiving drum is mounted upon the shaft I59 which is rotatably carried in bearings I5I, I52'and I59. The sleeve 45 carries keyedthereto ,in. any suitable manner the slot I94 of the hub thereof with the pin I of the shaft I59. A compression spring I99 is captured on thesleeve I91,'which is secured to the shaft I59 in any suitable manner as by a pin I99, by the engagement of's'aid spring I99 between the nut I99 adjustably mounted upon the sleeve I91 and the end I19 of thehub of the plate The spring pressure between the adjustable fixed nut I99 and the end I19 of the hub forces the plate I99 of the friction clutch into frictional engagement with the frictional surface I19 between the plates I9I and I99.

Consequently the motor 29 drives the receiving drum 2I by means of drive shaft 99 which through the spiral gear 49 is connected to the gear 44 which rotates the hollow insulated shaft 45 which through the friction clutch I92 rotates the shaft I59 upon which the receiving drum is mounted.

The receiving drum 2I is electrically grounded in the frame of the device while the recording stylus, hereinafter described, is connected to the opposite terminal of the electrical circuit for the purpose of passing a current from the stylus through the recording paper to the receiving drum in order to produce markings on the recording paper corresponding to the intensity of the current passing therethrough.

As will be noted in Figures 2 and 5 the receiving drum preferably is a hollow member comprising end pieces I99 and I9I to which is secured the outer surface I9I of the drum and which comprises hubs I92 and I99 for securing the drum and suitable fastening means such as the screws I94 and I95 for connecting the receiving drum 2I to the shaft I59.

In order to provide for an eflective translation of light modulations into electrical impulses suit- Accordingly, the scanning device 202 should be arranged in such a manner that the pencil of light therefrom will impinge upon the surface of the transmitting drum and move along the drum A of an inch during each revolution of the drum so that the picture variations will be translated into corresponding electrical impulses along a continuous spiral path of an inch wide on the transmitting drum. Y

In order further to maintain the correlation of the movement between the scanning device 202 and the transmitting drum 20, it is preferred that the drive of the scanning device be mechanically interlocked with the drive of the transmitting drum and actually that it be a function of the rotation of the drum.

Accordingly, as is seen in Figures 2, 4 and 5, the scanning device 200 is driven by a screw 2" formed upon the shaft 2i I which is rotatably carried in bearings 2I2 in the side walls or frame of the machine. The shaft 43 which drives the transmitting drum carries at one end thereof a gear 2I5 keyed thereto and rotatably therewith. Gear 2I5 meshes with and drives the spiral gear 2 I 6 which is keyed to and mounted upon the shaft 2i I thus rotatably driving the shaft 2!! in its bearings 2 I8and 2I8, which, as is seen particularly in Figure 2, are mounted upon the side walls or frame of the device. The opposite end of the shaft 2 I 1 carries a worm or spiral gear I2I which meshes with a similar gear 3 upon the shaft 2I I thus in turn driving the screw 2H] and causing the scanning device 200 to travel in accordance with the direction of rotation of the screw 2I0. By the proper arrangement of gear ratios and by the proper arrangement of the diameter of the screw 2H! and the pitch thereof, the scanning device 200 may be caused to travel laterally along the transmitting drum 20 in the desired path and at the desired relative speed to effect the spiral scanning path above described due to the concomitant rotation of the drum 20..

Referring now more particularly to Figures 2, 3, 5 and 14, the scanning device 200 comprises a main base or platform 220, said main base or platform comprising preferably a main front support bar MI and a lateral support bar 222. The lateral support bar 222 is perforated at 223 to permit the passage therethrough of the screw 2H1 and the shaft 2I I. The perforation 223 is preferclearly seen in Figures 2, 3 and 12 by the rollers top and bottom respectively of the stationary rectangular bar 23'. I

The stationary rectangular bar 232 is fixedly supported between the side walls of the main frame by means of screws 222-231, passing through perforations therein so that the rectangular bar 23! is fixedly held in the lugs 23! and 233. The roller 232 is rotatably mounted, as is seen in Figure 12, on the pin 2" which is journailed in the bearing 24.. The bearing 2 is rotatably captured at the end 241 of a screw member 232.

The journal 2 is rotatable with respect to the screw 2" and is therefore so arranged that it will align itself parallel to the path of movement of the scanning device 232 and accordingly will, during the movement of the scanning device22ll lie along the top of the fixed rectangular bar 3!.

The screw 2 provides for an adjustable mounting of the bearing 2 with respect to the rectangular bar 225. The screw 2" is rotatable in the threaded perforation 252 of the rear end 253 of the portion 222 of the platform 220 and hence rotation thereof will cause the screw 2" to rise or fall, thus making the roller 222 adjustable with respect to the platform and making its engagement with the top of the rectangular bar 235 adjustable.

A lock nut 25 is utilized'to lock the adjustment, once it has been made, in place. Rollers HI and 232 are rotatably mounted on pin 280 and 26I in the bearings 232 and 262 which are spring biased by the leaf spring .2" towards the under side of the rectangular bar 235. The leaf spring 2" is fastened to the rear end 253 of the platform 22. by means of screws 2" and 261.

Accordingly, by this means, the rear end of the platform 22l of the scanning device 200 is resiliently but positivelv in slidable, frictionless engagement with the rectangular bar 22! which serves to guide it. The front end is supported by the shaft 22f. The length of the opening 225 in front of the platform 22' cooperates with the shaft 22! particularly when the shaft closely approaches in diameter the size of the opening 225 to position the scanning device against anv twisting or torque which may occur owing to any unevenness in the lateral movement thereof.

The screw 2H! serves, in addition, to fixedly arrange the scanning device so that its path of movement will necessarily be parallel to the trans mitting drum 20 and so that any tendency for the scanning device to twist even slightly will be completely obviated. The screw 2IIi serves, in the manner hereinbefore mentioned, as the motive power for the scanning device 203, rotation thereof causing a constant lateral movement of fixed degree of the scanning device 203 in fixed relation to the transmitting drum 2..

The scanning device itself comprises a light source 21! preferably an electric bulb, suitably removably mounted in a socket "I (Figure 3). The socket 21I is vertically adjustable by means of the mounting thereof on the shaft 212 which is in threaded en a ment with the journal 213 so that rotation of the knurled knob 214 will cause thesockettoriseorfallverticallytobringthe light source 212 in alignment with the optical Tiiesocketfllisalsomounteduponaslidable Platformfllwhichmlsmoreparticulariyseen innsureauidsblememm gmsmm whicharelttachedtotheflangsfll whichin I, III and In, these rollers registering with the 16 turn by man; of m I m I. a fastened to the front 22I of the main platform 220 of the scanning device 200.

The horizontal position of the light source 210 a with respect to the optical system may be readily adjustable horizontally by means of the knurled screw 290 which isfreely rotatablymounted in the opening 29I in the front 22| of the main platform and which is fixed against longitudinal movement by the cooperation of the knurled knob 232 and the fixed stop 293. The end of the screw 290 is at 294 in threaded engagement with a flange 235 of the socket carrying platform 218 so that rotation of the screw 290 by reason of the'fact that the screw itself is fixed against lon itudinal movement will result in forward or backward movement of the socket carrying the platform 213, thus resulting in an adjustment of the light source 210 with respect to the optical system.

As is seen more particularly inFigure 3, the light source 210 is preferably enclosed by a shield 300 having an opening 30I which registers with the main tube 302 of the optical system. By means of a suitable lens system comprising a lens a mounted at 303 (Figures 2 and 3), the light from the light source is concentrated into a pencil of light preferably .01" in diameter at the point 304 (Figures '2 and 5), where it comes in contact.

with the transmitting drum 20.

A means I22 for translating light impulses into electrical impulses, such as"a photoelectric cell, is mounted on the forward projection I23 of the scanning device platform 220. An additional optical-system I24 comprising at least the lens 343 is so arranged (Figure 2) that the reflected light from the transmitting drum 20 is concentrated by the optical system I24 upon the photoelectric cell I22 to translate the light modulations into electrical modulations suitable for transmission by a telephone, telegraph, radio or in any other suitable manner, in a manner now well known in the art, the signals being transmitted by any of these media in various ways now known to the art as for e rample shown in my'U. 5. Patent No. 2,047,863, filed July 14, 1936.

The engagement of the scanning device with the driving screw 2I0 is a releasable one, as is seen particularly with reference to Figure 14.

That is, the side portion 222 of the scanning 222 of the scanning device. The lever 3| I is restrained from longitudinal movement along its shaft 3|2 by being mounted either in a suitable annular recess of the shaft 3I2 or by any suitable washer or other retaining means which, however, should be of such a nature as to result in c a rigid lateral connection between the lever 3H and the side member 222 so that any lateral movement imparted to the lever 3 will immediately result in corresponding movement of the entire scanning device.

A spring 3I5 is caught at one end on the pin 3I6 of the side member 222 and is wound about the pin 3I2 terminating at the opposite end 3I'I beneath the lever 3 in such position that the bias of the spring is translated into an upward movement of the lever 3I I. The notch 320 in the lever 3 is threaded so as to correspond to the thread of the screw 2I0. The spring 3I5 causes the notch 320 of the lever 3 to be pressed against the screw 2! so that rotary movement of the screw 2I0 will result in lateral movement of the lever 3H and corresponding lateral movement of thescanning device platform 220 and, of course, corresponding movement of the scanning device 200.

It will be noted, particularly from Figure 14 however, the engagement of the lever 3II with the screw 2I0 is a releasable one and this release may be obtained by means of the push pin 325. The push pin 325 is mounted in a perfora tion 326 of a lug 321 extending from the side member 222. The perforation 326 is of sufficient length so that the push pin 325 is maintained substantially vertically. The lower end 329 of the push pin 325 abuts against the top surface of the lever 3I I. p

A pin 330 or other suitable'stop may be provided beneath the lug 321 to prevent undesired or accidental removal of the push pin 325 from the device. The opposite end of the push pin 325 terminates preferably in a knurled knob 330 which as isseen in Figure 1, projects through the slot 33I in the top of the outside cover of the machine,

Depression of the knurled knob 330 of the push pin 325 results, as is shown in dotted lines in Figure 14, in a disengagement-of the scanning device from the screw 2I0 so that the scanning device may be slid to any desired position. For

35 instance, when it is desired to receive impulses on the receiving drum 2 I,.it is not necessary or even desirable for the scanning device to operate. According'ly, depression of the knob 330 of the push pin 325 will permit'a sliding of the scanning device 200 to one end orthe other of the shaft 2 so that the notch' 320 will be out of engagement with the screw 2H! and accordingly there will be no power connection between the shaft 2I I and the scanning device 200,-and accordingly, therefore, the scanning device will remain stationary with respect to the transmitting drum and will not operate.

The lateral movement of the receiver-scanner device is obtained in substantially the same way.

Referring more particularly to Figures 2, 4 and 10, the shaft I50 of the receiving drum 2| carries at one end thereof fixedly mounted thereon and rotatable therewith a gear 340. The gear 340 meshes with the idler 34I which in turn meshes with the gear 342 which is fixedly mounted upon and rotatable with the shaft 343 which carries the screw 344 which in turn drives the receiverscanning device. 1 q

As is seen most particularly in Figure 15, and as may be seen in Figures 2, 3 and 5, the receiving-scanning device 350 comprises a main carrying platform 35I of insulating material having side flanges 352 and 353. The stylus carrying '-rod 354 is pivotally mounted on the pin 400 which is passed through perforations in the flanges 352 and 353.

As will be noted particularly in Fig. 15, owing to the insulation construction of the main platform 35I and its associated flanges, the stylus is electrically isolated from the remainder of the mechanism.

The stylus carrying rod 354 carries preferably upon the upper surface thereof, contact carrying means comprising-an angular lug 356, one flange of which preferably is fastened by rivet or screw 351 to the stylus carrying rod 354 and the other flange of which carries an adjustable screw 353 or other looking or securing device for creating and maintaining an electrical contact between the wire 35! and the stylus carrying rod354.

The stylus carrying rod 354 carries at the front end thereof the stylus 365 which ismounted in the bifurcated front end 365 of the rod 354 by means of the screw 331. The stylus itself is adjustable both as to angle and depth of mounting, in the bifurcated end 368 of the rod 354. The stylus 355 comprises preferably a main portion 8% and an impulse transmitting needle head 3. The stylus head 3H preferably is .01" in diameter or less, in order that an electrical ing paper upon the receiving 2,295,072 stylus-carrying rod m downwardly mum to drive the stylus head 3' against the recorddrum. Asismore clearlyseeninl 'lgurea,themain platform "I of the stylus scanningdevice is arranged to limit any downward movement of the impulse of diameter corresponding to that of the transmitted impulse be recorded upon the paper.

The base or main insulating platform of'the stylus recording mechanism comprises a perforation 3'55 having journals 315 at at least one side thereof in order to receive the mounting rod 31?. as is seen in Figure 5, the mounting rod 3?? is fixedly arranged in the riser 13 of the frame on one side and in the side wall member at the other side, and provides a slidable support for the stylus platform 35l.

As i also seen in Figures 3 and 15, a rail or flange 380 is mounted on the riser 313 of the main frame by screws 333 or in any other suitable manner so that it projects upwardly to a position adjacent the stylus platform 35!.

Spring 38! is secured at 332 to a pin 333 mounted on the frame 353 of the stylus platform 35f and at the opposite end at 334 abuts the rear side of the flange or guide 380. Thus spring "I wound about the journal 316 serves therefore, by this engagement, to cause the stylus platform, 35l to rotate about the shaft 311 and thus to drive the stylus head 3" towards the receiving drum 2i and the opposite end 330 of the stylus platform against the screw 344.

The opposite end 390 of the stylus platform 35l is notched at 3M and threaded in a manner corresponding to the threads of the screw 344 so that when under the bias of the spring 3", the notched portion 33! is driven against the screw 344, there is a driving engagement between the shaft 343 and the stylus platform 35l.

Rotation of the shaft 343 through this power transmitting connection, therefore, results in stylus carrying rod 354 with respect thereto. The rail or flange or other guiding means 333 is necessary merely for the purpose of providing a purchase or support for the spring 3", whatever the position of the stylus may be, and hence any other suitable medium may be used as, for

instance, a rod mounted in a similar position.

Where the friction between the end 334 of the spring 33! and the rail 33! or other such sliding member may become too great, a suitable roller or other friction reducing means may be pro- ,vided on the end 334 of the spring. By this means, therefore, the receiving-scanning device and its stylus may be connected or disconnected from power transmitting connection with the 'shaft 343 and placed in a position at one end or the other of the receiving drum where it will 'not effectively record any impulses whatever. Likewise, and in a similar manner, the stylus may be placed appropriately for recording; and the lateral feed, by means of the screw 344 may be utilized to obtain the necessary helical scanning operation.

The stylus head 3' may have any suitable conformation and be made of any suitable material for transmitting the received electrical impulses to the recording paper. Owing to the fact that preferably a recording paper is to be used, the stylus head 3" will preferably be rounded off so as not to snag, catch or otherwise disturb, tear or distort the paper. However, by the present novel construction, any necessity for such particular treatment of the stylus head may well be obviated particularly by reason of the fact that the motion of the stylus with respect to the paper is a trailing one.

While normally in many of the prior stylus recording devices,-the stylus is held against the paper in such manner that the axis of the stylus is perpendicular to any tangent drawn to the paper at thatparticular point; in the present stylus, the action of thestylus itself is a trailing tangential one, normally permitting-the stylus to lateral movement of the stylus platform 35! and the power transmitting mechanism to obtain the necessary lateral movement for reception.

In order to provide for any resilient adjustment that may be necessary and for a more delicate adjustment, the stylus carrying rod 354 is rotatably mounted on the pin 403 which is carried between the flanges 352 and 353. A spring .40! is captured at 402 in a perforation 433 of the flange 353 and is wound about the pivot pin 408. -The opposite end of the spring is, at 434, engaged with the top of the stylus-carrying rod 354 and the spring therefor is so arranged that it is biased to drive the bifurcated end 355 of the ride over any irregularities and normally tending to overcome any unevenness in the operation thereof. This is particularly so sincethe stylus is spring supported by means mainly of the spring 43! as well as also by the spring "I so that it maygive or rise to any irregularity in the surface of the paper or to any other snag in condition which may occur in operation.

By this novel mounting of the stylus, therefore, andthe novel arrangement of the angle of the stylus with respect to the paper, it is necessary, therefore, only to make sure that the hearing surface of the stylus does not exceed the width of any particular scanning line and further to make sure simply that the bearing surface of the stylus is suillciently smooth to avoid any snagging-or tearing of the paper, keeping in mind that the motion of .the stylus is a trailing, tangential one.

The particular arrangement of springs for causing the stylus to maintain proper contact with both the driving means and the recording means may be'varied as circumstances require. Thus, for instance, any suitable spring may be placed, if desired, between the platform 354 and the stylus carrying rod 354 in order to bias the When the enlarged portion of the cams 6H stylus carrying rod into engagement with the paper. Or the stylus-carrying rod may. in a suitable embodiment, itself consist of a leaf spring with suitable adjustable stops being arranged thereabouts in order to limitthe necessary movement thereof. I

The means for engaging the stylus carrying platform "I with the screw 6 of the shaft 666. may itself be varied. Thus. for instance, instead of utilizing a spring of the type of the coil spring 36I, the rail or guide 666 may itself be modified to constitute a spring member Or a spring biased member for holding the end 666 of the styluscarrying platform in engagement with the screw 3. And accordingly, therefore, the raising of the stylus-carrying platform "I will cause-the spring or spring biased member substituted for the rail 666 to be shifted temporarily out of position during the disengagement.

The stylus scanning device 666 is driven not from the main drive of the motor, but from the shaft I 66 upon which the receiving drum 2I is mounted. Its movement is exactly in accordance with the movement of the receiving drum 2| and any variation in movement of the receiving drum results in a corresponding variation in the movement of the stylus scanning means 666.

Impulses are detected and simplified by any suitable receiver,- and conducted to th stylus and therefrom through the recording paper into the recording drum to produce a record corresponding to the received impulses employing suitable recording paper in the manner described more specifically in my application Serial No. 240,675 and 266,709. g r

When the device is set for transmission, that is, when a picture or other matter to be transmitted is wrapped about the transmitting drum 2| and the transmitter-scanning device 266 is, by means of the push button knob 666 moved to its proper position, then a suitable synchronizing signal may be sent, preferably once during each revolution 'of the-transmitting drum as for example described in my U. 8. Patent No. 2,047,863.

This synchronizing impulse, preferably is sent during that moment when that portion of the transmitting drum 26 which does not contain any picture to be sent passes in front of th scanner. Accordingly, the synchronizing impulse is sent preferablywhen the fastening means is in front of the transmitting scanner'or during the interval between the two edges of the picture which is sent.

As is seenin Figures 3'and 5, a cam switch 666 is suitably mounted in an insulating block "I which is supported by screws 662, 666, or in any other suitable manner upon an angle iron 666 fastened in any desired manner to the main frame. The cam switch comprises a central contact 6I6 and two auxiliary contacts 6 and "2.

When the central contact M6 is in engagement with auxiliary contact 6I2 (Figure 3) then the ordinary picture impulses from the photoelectric cell 6I6 are transmitted. Central contact 6I6 is thus normally'arranged so that it is in engagement with contact 6I2. Cam 6 and 6I6, Figures 3 and 5,, are mounted upon the shaft 66 of the transmitting drum and are so aranged that an enlarged portion thereof will abut th central contact 6I6 once during each revolution of the transmitting drum. The enlarged portion of the cams 6H and H6 normally coincide in circumferential position with the fastening means of the transmitting drum herein described.

and M6 engage central contact 6I6, it breaks the connection between contacts 6I6 and 6| 2, thus breaking theconnection between the photoelectric cell I22 and the transmitting apparatus and makes the connection between contacts 6I6 and III, thus connecting into the transmitting circuit any suitable synchronizing impulse which may be used.

Synchronization at the receiving end maybe obtained in any suitable manner including any of the various methods now knownv and shown in -my above referred patents and applications.

I have, howeyer, illustrated one type of synchronizing means which may be utilized for this purpose.

a Plate I66 of the friction'clutch I62 (Figures 5 and 11) comprises a projection or hook 666. Plate I66 is, of course, keyed to the shaft I66 so that when the hook 666 strikes any impediment such as, for instance, the end of the lever "I, then the rotation of shaft I66 and the corresponding rotation of receiving drum 2| will be stopped. Owing to the fact that the engagement between the plates I6I and I66 is a frictional one, this stopping of the rotation of plate I66 and of the rotation of the shaft I66 will not prevent continued operation of the motor 26 and rotation of the plate, I6I.

As soon as the lever SM is removed from en- I gagement with the hook or stop 666 of the plate I66, then the frictional engagement between the plates I6| and I66 will result in the immediate engagement of the receiving drum I6I. Lever "I is pivotally mounted on the shaft 662 and is normally spring biased into tangential engagement with the surface of the plate I66. The .bottom end of the lever 66I carries an armature 666. Electro-magnet 666 is so arranged that when energized, it will attract the armature 666 and cause rotation of the lever "I about a pivot 662. Such attraction of the armature 666 will release the engagement between the hook or stop 666 and the end of the lever I and permit further rotation of the plate I66 and consequently oi the shaft I66.

During each revolution of the receiving drum 2| and therefore of the plate I66; the hook or stop 666 comes into'contact with the end of the lever "I. The synchronizing impulse, when received, energizes the magnet 666 to attract the armature 666 of the lever MI and hence to release the lever 66I from its engagement with the hook and permit continued rotation.

As is further seen in Figure 10, the shaft ill of the receiving drum also carries the cam III which carries the projection 6| I thereon. Projection 6 cooperates with the cam switch 6I2. Cam switch 6I2 comprises switch members 6|6, 6H and 6|6 mounted upon an insulated block 6I6 which is secured in any suitable manner, as, for instance, by screws 6", 6" to the angle iron "6 which is in turn secured to the base 26.

Normally switch contact 6I6 is engaged with contact M6 to energize the stylus recording equipment. cam 6I6 strikes the contact 6|6, it breaks the circuit betwen the contact 6| 3 and H6 and establishes a circuit between contact 6I6 and 6, which circuit energizes the magnet 664.

The projection ii I- of the cam is so arranged with respect to the hook 666 of the plate I66 that it establishes a circuit between contacts 6|6 and 6 simultaneously with the stopping of the plate I66 by the lever 66I. Consequently, any

When the projection 6 of the instead will b transmitted synchronizing impulse which will then be received will not be transmitted to the stylus but to the magnet Ill. Energization of the magnet 04 by the synchronizing impulse will against start the rotation of the plate I63 and of the shaft I50 of the receiving drum 2| in the manner hereinbefore described and simultaneously then continued movement of the projection 8H of the cam ill will reestablish the circuit between contacts "8 andJlO, thus reenergizing the stylus recording equipment.

By this means, therefore, a channel for reception of the synchronizing impulse is established once during each revolution of the recording drum 2! and the picture signals are received and translated during the remainder of the revolution of the drum. Accordingly, gear ratios should be such that the irecording drum 2| should rotate slightly (not more than 1 per cent) faster than the corresponding transmitting drum, picture signals of which are received, to insure that the recording drum will reach the position for reception of the synchronizing impulse before the synchronizing impulse is transmitted.

The recording drum 2| is therefore momentarily halted once during each revolution. thereof and upon reception of the synchronizing impulse is permitted to operate once more, all in the manner above described.

Where similar units are used, either at a central station and a mobile unit, or between mobile units, the synchronizing impulse therefore sent by means of the circuit established through the synchronizing contacts "I received by the magnet "4 (Figure 11) when the circuit therethrough is established by the cam Bill and contact 8!! (Figure 10) Various means may be utilized in order to wrap the picture to be transmitted about the transmitting drum and in order effectively to secure the recording paper to the receiving drum. In Figures 6, '7, 8 and 9 I have shown a preferred the (Figure 3) may be said sheet to said transmitting drum for scanning purposes.

in Figure 8, while a The procedure, of mounting the transmitted sheet upon the transmitting drum may thus be greatly facilitated. Thus, as seen in Figure 8, the mounting plate J00 may be tilted to one side and an edge Ill of a sheet II. to be transmitted inserted thereunder. The sheet may then be wrapped around the drum until the opposite end H1, as seen in Figure 9, may be brought beneath the opposite edge of the mounting plate. The mounting plate may then by finger pressure be twisted in the opposite direction and the opposite edge I ll of the transmitted sheet ll! be inserted beneath the mounting plate and secured thereby. The end result may readilg be seen in Figure '1, where the transmitted sheet III is securely held in place by the mounting plate 1".

Instead of relying upon finger pressure to rotate the mounting plate from the position shown in Figure 8 to the position shown in Figure 9, the shaft I02 may readily be utilized. One end of the shaft 102 may terminate in a crank member 120. Owing to the fact that the members H2 carrying the pins III are fixedly secured to the shaft I02, a slight rotation of the crank III in one direction will cause rotation of the plate 1 l2 and a tilting of the pin 1" in the manner shown rotation of the crank III in the opposite direction will cause a tilting of the pin 105 in the manner shown in Figure 9 so that it will not be necessary to rely solely on finger pressure upon the mounting plate 1" in order to permit insertion of the end of the transmitted sheet, but a mere manipulation of the crank 110 for this purpose will accomplish this simplified form for facilitating the wrapping of r the sheet to be transmitted about the transmit- I ting drum.

(Figures 6, 7, 8 and 9) mounted at one I the axis thereof and spring held in contact with the drum by means of spr gs 1M, 1M engaging the under surface of the plate 100 at one end of the springs and engaging the rod I02 fixedly arranged within the drum at the opposite ends of the springs.

Accordingly, while the mounting plate 100 is secured to the surface of the drum, the securement is a yielding one which may readily be arranged to permit a raising or sliding of the plate for the purpose of securing the sheet to be transmitted to the transmitting drum.

Pins I05, 105 project inwardly from the mounting plate 100 and pass through the perforations 106 in the drum 20 into the interior of the drum. These pins may be either an integral part of the mounting plate 100 or may be secured thereto in any suitable manner. Pins HIS are releasably held between pins 1 l0 and III on crank members "H2 which are fixedly mounted upon the internal shaft 102. As new will readily be seen, by reason of the flexible mounting of the securing plate 100, the plate may readily be moved in order topermit the insertion or mounting of a sheet to be transmitted upon the transmitting drum while nevertheless securely affixing the result.

Crank I10, of course, is so arranged within the periphery of the side of the transmitting drum that it will not interfere with any of the other mechanisms of the duplex transceiver.

\ Obviously, of course, as hereinbefore described, the transmitting drum 2| may readily be removed to facilitate the wrapping around of any transmitted sheet which is to be sent. The same system may be applied if desired with a drum which is to remain stationary and, if necessary, the same system may be utilized in connection with the receiving drunrll.

I prefer, however, that for receiving purposes an even more simplified system be utilized. Thus I provide spring garters III (see Figures 2 and 3) at either end of the receiving drum 2| so arranged that after the recording paper has been wrapped therearound, the garters may be placed over the paper and cause the paper to be securely amxed to the recording drum for recording purposes.

Each of the parts herein set forth has obviously been described in its preferred form and in the commercial embodiment heretofore found completely successful.

The adaptability and use of the device in mobile units cannot be over-emphasized. Thus, for two way facsimile communication between plane and plane, or plane and ground, or for two way facsimile communication between police automobiles, or police automobiles and central station,'

or for any other type of two way facsimile communication wherein the device must be simple in operation, light in weight and economical and inexpensive in construction, the present device receive andtransmit the same or different facsimile records simultaneously upon a single duplex unit.

By the use of the present device, duplication of mechanical elements is, avoided. The very mechanical elements which drive the transmitting drum and cause the operation thereof are utilized without any expensive switchover mechanism (mechanical or electrical) in order to drive the receivingapparatus. As a matter of fact, no such switchover apparatus is necessary at all since for reception purposes it is necessary only to wrap the recording paper about the receiving drum, make sure that the receiving stylus is engaged with its drive mechanism and connect the duplex device to a suitable receiver.

For transmitting it is necessary only to wrap the material to be sent about the transmitting drum, make sure that the scanning device is engaged with its drive mechanism at a point near one edge of the material to be transmitted, and connect the device to the transmitter. No other switchover mechanism. of any kind whatever is necessary.

Perhaps the only mechanical adJustment which may at any time be required for the present machine is further to insure that the transmitting or receiving drums are 'at a correct position for starting. For this purpose it would be necessary merely to rotate th receiving and transmitting drums several degrees to a correct startingposition.

Owing to the fact that very high gear ratios are used and owing to the fact that mechanical advantage is on the side of the motor, or rather of the motor shaft 36, and owing to the fact that the gear connections between gears 40 and M and gears 39 and 42 are self-locking or selfbraking, it may be difficult to rotate the drums 20 and 2! by hand. Accordingly, for purposes of such adjustment the shaft 36 may, as is seen particularly in Figures 1 and 4, be extended out beyond the front of the machine to terminate in the knob 38. Rotation of the knob 38 may be utilized to shift the drums 20 and 2i several degrees in any direction which may be necessary to reach the edge of the recording or transmitting sheet before the operation is started. This is the only other mechanical adjustment which may be necessary and is utilized merely to insure that the scanning operation, whether transmitwhich he may have made during the flight or trip, merely to wrap the material to be transmitted about the transmitting drum, securely fastening the edges thereof beneath the mount- 8 plate 100 in the manner hereinbefore described; depress the push button knob III and thereby push the scanning mechanism over to the starting point of the scanning operation; rotate the handle 38 to make certain that the commencement of the scanning operation starts at the proper corner of the picture and then connect the duplex mechanism to his radio transmitter, make sure that connection is made with the receiving station, and commence the transmitting operation.

During the transmitting operation, the operator may, if he so desires, move the stylus of the receiving portion of the unit over to one side so that it will not traverse the receiving drum during the operation. This is not an essential movement unless the wear of the stylus head is to be avoided.

For receiving it is necessary for the operator merely to wrap a recording sheet about the receiving drum 2|, securing the same in place by means of the garters IZI, place the stylus head, i

, by the method hereinbefore described, in position at one side of the recording sheet, and turn th knob 38 so that the stylus head starts its recording at one corner of the recording sheet and connect the device with the receiver of his radio or with any other suitable facsimile receiver. For this purpose, the operator may, if

- he so desires, move the transmitter scanner over to one side by depressing the push-button 330, but it is not essential that he do so.

In a suitable device it would be possible to utilize a single drum for both transmission or reception by maintaining the mounting of the scanning device in the position shown for instance in Figure 2 and by moving the operating shaft of the recording stylus to such position that it will cooperate with the single drum. In such case by the proper use of a friction clutch on the single drum and means for switching .over from synchronizing impulse transmission operation to a synchronizing impulse receiving operation upon the single shaft of the single drum, and by proper arrangement for changing ting or receiving, starts at the proper corner of the sheet.

In any proper case, where weight is not an essential factor and where absolute convenience in speed and operation is not an essential requirement, obviously a light scanning system on a sensitive record sheet may be utilized for reception. In such case a suitable shield should I through the narrow opening I30, Figures 1 and 5,

in the front of the mechanism.

Accordingly, in the use of the present machine it is necessary for the airplane pilot or automopursuit ships, reconnaissance planes, small boats bile operator or the operator in any other mobile unit; in the event he wishes to transmit any material, such, for instance, as charts or maps the gear ratio slightly when the friction clutch is permitted to operate for reception, a single drum may be utilized both for transmission and reception. For this purpose proper connections should be made with respect to the single transmitting-receiving drum for properly grounding the same.

Various other embodiments and uses of the present device will now be clear to those skilled in the art. Thus apart from mobile use between mobile units and mobile use between mobile units and stationary central stations, particularly in those cases, such as in light weight airplanes,

and lightweight automobiles where weight is an important factor, the present device may well have importance in ordinary non-mobile station to station operation or station to subscriber operation.

It may well have extreme importance in alarm systems, signalling systems and communications systems of various kinds, whether portable or stationary.

With proper adaptation a continuous sheet facsimile recording system may-be utilized in con- I said recording drum at a predetermined spe nection with the recording portion of the duplex device. I

The synchronizing impulse transmitting and receiving means may be varied to suit particular circumstances, the essential element of the present invention being that in a single unitary duplex machine both transmitting and receiving functions may beembodied in a light weight simple, readily operated form.

' Many other variations in particular portions of the device may be made and many other variations in the uses to which the device may be put may now be understood by those skilled in the art all within the spirit of the present invention, the essential portion of which comprises the combination in a single duplex unit of facsimile transmission and reception apparatus without necessarily duplicating any of the mechanical elements.

Likewise many other novel uses of the various portions of the present invention will now be clear to those skilled in the art including the arrangement and operation of the transmission scanning system and reception scanning system.

I prefer, therefore, to be limited not by the specific disclosures herein but only by the. appended claims.

I claim: Y

1. A duplex facsimile lransmitter and receive unit comprising a transmitting drum, a recording drum, scanning means individual to each of said drums, said means comprising a photosensitive scanning member operably connected to said transmitting drum and ,driven in synchronism therewith, and a recording element operably connected to said recording drum and driven in synchronism therewith, means including a single source of power for driving said transmitting drum at a predetermined speed and for driving ed different than the speed of said transmitting drum, said drums being operable simultaneously, the transmitting drum rotating continuously and the recording drum rotating intermittently.

2. A duplex facsimile transmitter and receiver unit comprising a tranmitting drum, a recording drum, scanning means individual to each of said drums, said means comprising a photosensitive scanning member operably connected to said transmitting drum and driven in synchronism therewith, and a recording element operably con-.

nected to said recording drum and driven in synchronism therewith, a power source, and power transmitting connections from said power source to said transmitting drum, recording drum and scanning means, and means in said power transmitting connections for driving said transmitting drum at one speed and said recording drum at a different speed, said drums being operable simultaneously, the transmitting drum rotating .continuously and the recording drum rotating intermittently. I 1

3. A duplex facsimile transmitter and receiver operation of said drums at predetermined different speeds and means for driving the scanning therewtth, and a recording element operably connected to said recording drum and driven in synehronism therewith, a power source, a drive shaft operated therebv, a power transmitting connection between said drive shaft and said transmitting drum. a power transmitting connection from said drive shaft to said recording drum, said power transmitting connections permitting the operation of said drums at predetermined different speeds, means for driving the scanning means of said drums, and a clutch between the drive shaft and the shaft of said recording drum.

5. A duplex facsimile transmitter and receiver unit comprisinga transmitting drum, a recording drum, scanning means individual to each of said drums, said means comprising a photosensitive scanning member operably connected to said transmitting drum and driven in synchronism therewith, and a recording element operably connected to said recording drum and driven in synchronism therewith, a power source, a drive shaft operated. thereby, a power transmitting connection between said drive shaft and said transmitting drum, a power transmitting connection from said drive shaft -to said recording drum, said power transmitting connections permitting the operation of said drums at predetermined difunit comprising a transmitting drum, a recording drum, scanning means individual to each of said drums, said means comprising a-photosensitive scanning member operably connected to said transmitting drum and driven in synchronism therewith, and a recording element operably connected to said recording drum and driven in synchronism therewith, a power source, a drive shaft operated thereby, a power transmitting connection between said drive shaft and said transmitting drum, a power t ansmitting connection from said drive shaft to said recording drum, said power transmitting connections permitting the ferent speeds, means for driving the scanning means of said drums, a clutch between the drive shaft and the shaft of said recording drum, and

means operable upon the shaft of the recording drum for intermittently interrupting the said power transmitting connection between the drive shaft and the recording drum shaft and for reengaging said connection in response to synchronizing impulses.

6. A duplex facsimile transmitter and receiver unit comprising a transmitting drum, a recording drum, scanning means individual to each of said drums, said means comprising a photosensitive scaninng member operably connected to said transmitting drum and driven in synchronism therewith, and a recording element operably connected to said recording drum and driven in synchronism therewith, a power source, a drive shaft operated thereby, a power transmitting connection between said drive shaft and said transmitting drum, a power transmitting connection from said drive shaft to said recording drum, said power transmitting connections permitting the operation of said drums at predetermined different speeds, and means for driving the scanning means of said drums, and means associated with the transmitting drum for originating synchronizing impulses.

'7. A duplex facsimile transmitter and receiver unit comprising a transmitting drum, a recording drum, scanning means individual to each of said drums, said means comprising a, photosensitive scanning member operably connected to said transmitting drum and driven in synchronism therewith, and a recording element operably connected to said recording drum and driven in synchronism therewith, a power source. a drive shaft operated thereby, a power transmitting connection between said drive shaft and said transmitting drum, a power transmitting connection from said drive shaft to said recording drum, said 1 1 drum operating slfaft driven by said powershaft,

a recording drum operating shaft driven by said power shaft, a transmitting drum removably 4 mounted outside the cover in powertran'smitting transmitting and recording drums being operable at predetermined different speeds, means for driving the scanningmeans of said drums, a clutch between the drive shaftand the shaft of said recording drum, means operable upon the shaft, of the recording drum for intermittently interrupting the said power transmitting connection between the drive shaft and the recording drum shaft and for reengaging said connection in response to synchronizing impulses, and means associated with the transmitting drum for originating synchronizing impulses.

8. A duplex facsimile transmitter and receiver 'unit comprising a base, a cover therefor, a source of power mounted on-said base, a power shaft '20 driven from said source of power, a transmitting connection with said transmittingdrum operating shaft and a recording drum mounted outside the mechanism, and means operable from outside the cover for connecting and adjusting said scanning and recording means relative to their respective drums.

WIILIAMG. H. FINCH;

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