US2275249A - Phasing arrangement for telefacsimile machines - Google Patents

Description

March 3, 1942. A. G. .COOLEY PHASING ARRANGEMENT FOR .IELE FACSIMILE MACHINES Filed Nov. 28, 1959 .2 Sheets-Sheet 1 z mfg.

' ATTORNE Y.

March 3, 1942. A. G. COOLEY 2,275,249

PHASING ARRANGEMENT FOR TELE-EACSIMILE MACHINES I Filed Nov. 28, 1939 2 Sheets-Sheet 2 ATTORNEY.

' duced.

received phasing signal.

, electromagnetic relay.

Patent ed Mar. 3, 1

UNITE-D 5 STATES? PA H OFFICE rmisma Anmmmmrroa rmrscsnma moms-s Austin G. Cooley, News. N. r, assignor, by. memo assignments, to Times Telephoto Equipment Inc., New New York York, N. 1., a'corporation of Application November 28, 1839, Serial No. 308,465

9 Claims. (Cl. 178-495) This invention relates to phasing arrangements and more especially to arrangements for phasing remotely controlled devices, such for example as tele-facsimile machines, telegraph machines and the like.

A principal object is to provide an improved phasing control circuit for tele-facslmile machines.

Another object is to provide an improved automatic phasing control arrangement for a fac- Fig. 4 is a detailed top plan magnet as shown in Fig. 2.

Fig. 5 is a detailed plan view of the trip magnet view of the trip as shown in Fig. 3.

simile. receiving machine whereby thetime -required to A feature of the invention relates to.a novel form of phasing control or trip magnet for a rotatable device such as a scanning drum, which is conjointly controlled by the drum-and by. a

eflect proper phasing is materially re-- 7 Fig. 8 is a lefthand elevational view of the trip magnet.

Referring to Fig. 1. the dotted rectangle in the upper lefthand corner represents any well-known form of tale-facsimile transmitting machine. For a detailed description of such a machine, reference may be had to Patent No.- 2,015,742.

. Merely for explanatory purposes, the machine is 'shown as comprising a scanning drum I, driven through suitable gearing 2, by a driving motor 3.

Another feature relates to an improved amplifier and control arrangement for a received phasing signal.

Afurther feature relates to a novel form of A still further feature relates to the novel organization, arrangement and relative location and interconnection of parts whereby a simplifled and improved phasing control is provided for remotely controlled machines.

other features and advantages not specifically v enumerated will be apparent after a considera-. tion of the following detailed descriptionsxand the appended claims.

-While the; invention will be disclosed as embodied in a tele-facsimile system, it will be understood that in certain of its aspects. the invention is applicable to other types of signalling systems or remotelycontrolled apparatus which? are required to be maintained not only in time synchronism but also in spatial synchronism or orientation with a transmitter or the like. Furthermore, the drawing is intended to be schematic and onlythose parts of a'tele-facsimile system are shownas' are necessary to an understanding of the features of the invention. Accordingly in the drawings, Fig. 1 is a schematic diagram of a typical tele-facsimile system embodying the invention.

Figs. 1 1 and 1, are wave diagrams; em.-

' planatory of the operation of Fig. 1'.

Fig. '2 isa detailed end view of' the recording drum and trip magnet assembly of Fig. 1..

ent relation.

' associated mechanism,,reference may behad to The subject matter to be transmitted is wrapped around drum l and scanned inthe manner wellknown inthe facsimile art by means of .a light source 4. and a light-sensitivecell i, the drum beingrotated and fed longitudinally the width of a scanning-line for each complete revolution. For a detailed description of such a drum and Patent No. 2,138,784. The drum lcarries atone longitudinal feeding mechanism can be. rendered Y ineffective as described in end, so as to be separate from the subiectmatter to be transmitted, a blackened band and a small white marker 1, which is adapted to be illuminated by light source I. onceduring each revolution of the drum so as to transmit aphasing impulse of relatively large amplitude. The phasing operation is usually. effected Just prior to the actualtele-i'acsimile transmission, and for this purpose drum l is coupled to motor 3 so that the said Patent-No. 2,138,-

784, whereby the drum can be continuously rotated with'the band 0 in optical alignment with source 4 and cell 5 and without longitudinal feeding movement of; the drum. Consequently, when drum I is rotated at synchronous speed by motor 3, there isgenerated in cell 5 once perv revolution of the drum a special phasing impulse.

Fig. 3 is another'viewsimilar to that of Fig. 2, but showing the drum and trip magnet in differ- I8 light from source, 4- is Where the tele facs'imile machine is of the type which'tr'ansmits the signals in the form oi" a modulated audio=frequency carrier e. g. 1800 C P. S..'the output of cell of a plurality of imment with respect to said shaft.

The special phasing signals are received at the remotely located receiving station and are amplified in the amplifier in of the tele-facslmile receiving machine. The recording lamp of this machine is indicated by the numeral ii and the last stage of the amplifier which feeds the recording lamp is indicated by numeral ii. A switch I3 is provided for controlling the lamp circuit. The scanning drum' l4 of the receiving machine is brought up to synchronous speed by a suitable power motor l5 and thereafter the synchronous speed is maintained by the-synchro nous motor it which is preferably of. the phonicwheel type. The stator or poles ll of the phonicwheel motor are arranged to be excited'by part of the 1800 C. P. 8. signal received from line L after amplification in amplifier i8. Preferably, the toothed rotor of the motor i8 is springcoupled to the shaft ofmotor I! so that the said rotor is capable of limited rotational displace- A push button switch is is provided and is normally in the position shown, whereby the circuit from the 60 cycle A. 0. supply 20 is disconnected irom motor i5. Likewise, when switch is is normal as shown, the cathode is connected to ground or the plate return circuit through contacts 23, 24. However, in order to phase the receiving drum i4 with the transmitted drum I, under control of the phasing signal 'ab'ove described, the attendant at the receiver holds the switch i9 operated fora few seconds. During this time, the motor l5 comes up to speed and rotates drum l4 until it is stopped by a latch 44 and armature; A slip clutch 51 permits the-motor ii to continue rotating. switch I9 is. first operated, it removes the short circuit from around the coupling resistor 14 so that when the phasing signal P of Fig. 1 is received, it flows through the coupling resistor 25. Resistor 25 is connected to the control-grid 28 and cathode 21 of a pentode amplifier tube 28 through a filter network comprising resistor 29 and condenser 30. This filter is so designed that it suppresses substantially all or the greatest part of the 1800 cycle component ,of Fig. 1*, but passes the group frequency" of the phasing impulses P. Consequently, the output of'tube 28 consists of a current having little or negligible 1800- cycle amplitude variations but with the phasing impulses P greatly amplified as represented in Plai The output of tube 28 is then fed to a trigger tube 3| which may be 0! the grid-controlled gaseous conduction type having its control-grid 32 blessed with respect to cathode 33 in any well-known manner so that. it

does not pass plate current until a phasing impulse of a predetermined minimum amplitude such as that of P Fig. i is-impressed on grid 32. Preferably, the output of tube 24 is resistance-coupled by resistor 34 and coupling condenser 35 to tube 3! and through a fllte'r network comprising resistor 38 and condenser I1. This filter, like the filter 19-40 is designed to suppress any i800 cycle ripple that may be present in the output of tube 2'4. Consequently, when the phasing impulse shown in Figs. 1 is impressed on grid n, the tube u inim. current, 75 it is male proper phase relation.

received at the same time that the contacts 44,

4|, are mechanically closed by the drum projection 44 engaging the slide 49 which is carried by the armature. The trip magnet and drum relation are shown in detail in Figs. 2 to 6. As

shown in Fig. 2, the trip magnet comprises a magnetic core 45 mounted on an L-shaped iron bracket 46 suitably fastened to the frame 41 of the machine. The armature 48 is pivotally attached as indicated by the numeral 50 between a pair of upstanding lugs on the vertical arm of the L-shaped member. The armature 48 has also slidably mounted therein the contact operating member 49, the forward end ii of which normally projects beyond the forward edge of the armature 48 as shown in Figs. 2, the slide 49 being held in this normal forward position by the contact spring 40a. Spring 40a is attached to the left-hand end of slide 49 bymeans of an insulator bushing 52. A retaining member 53 is fastened to the top of the armature to prevent the slide from becoming dislodged. The spring 460 is fastened to an insulator block 54 which in turn is fastened to the bracket 46. Also I fastened to block 54 is another contact spring Ma carrying the contact 4!. When the switch- 13 is operated, the armature 48 is held away from the core 45 by means of retractile springs 54 as the winding 39 is tie-energized. The end of the armature and the end of slide ii. are in when the position to be engaged by the stop-latch 44 on the drum immediately after the motor II is started (Fig. 2). Before the stop-latch 44 strikes the slide ii, the contacts 44, 4|, are'open. However, when the drum i4 rotates, the stop 44 engages the slide end II and moves the contact 44 into engagement with contact 4i thus preparing the above described circuit for the winding II.

The drum makes a very slight further rotational movement until it engages the end of armature 44 which thereupon acts as a rigid stop and prevents further rotation-of the drum. If after the closure of the contacts 44, 4|, a phasing impulse is received, sufllcient current is passed by the tube 3| to energize the winding 39 thus attracting the armature 48 and removing it from engagement with lug-44. The drum is therefore free to continue its revolution. Once the armst ure 48 has been" operated, and assuming the attendant has in the meanwhile released the push-button I, the said armature remains attracted to the core 45 by means of a locking circuit traceable from the positive terminal .48, winding 3!, resistor 54, contacts 51 and 24, to the negative grounded terminal of the supply source. Thus the armature 48 is maintained out of the path of the stop-lug 44 even after the attendant releases switch .II. From the foregoing, it will be seen that the drum cannot rotate unless the lug 44 engages the slide 44 at the same instant that a phasing impulse is received. If this phasing condition occurs, the drum contimies' to rotate andithe attendant of phase, then of course it will be momentarily understood of course that a suitable friction couplingil is provided between the drum shaft and the motor shaft so as to allow the drum to be stopped for phasing as above described with.-

- .out stopping the motor I5. Motor I! has sufficient power to keeprotating even though drum I4 is stoppedby latch 44. Motor l5 rotates at a speed close to the synchronous speed of motor l6l so that as soon as theclutch load is released, the motor lG-l'l falls into synchronism in a few thousandths of a second. Thus all that is necessary to effect the phasing operation is to operate the single switch is for a short interval only said low frequency signals while substantially .suppressing the carrier frequency, means to prepare said circuit-including a pair of contacts v operated when said other rotatable device is about of time usually until the drum ll-makes one or two complete revolutions. The operation of to be stopped by said trip magnet and means controlled by said amplifier for completing said circuit.

3. A system according to claim 2.in which a manually operable switch is provided to control a locking circuit for said trip magnet independently of said amplifier.

4. A phasing arrangement for the rotarymechanism of a telegraph receiving machine designed to receive a phasing signal from a distant transmitter in the form of a pulsating current having low frequency spaced modulations, said arrangement including 'anamplifier forthe phasing sig- .nal, a shiftable stop for engaging said mechanism' when out of phase with said transmitter,

i and means to energize said electromagnetic stopped and the attendant will be thereby apprised of the necessity of holding the switch I! closed for a further revolution of-the drum. When the proper phase relation isobtained, a regular click is heard by the engagement of member 44 and ii, whereupon the attendant may release the switch 19. When the switch It is released, the armature 48 is held attractedby the locking circuit above described.

Fig. 2 shows the drum inaposlti'o'n just prior to-the engagement of the lug 44 with the slide 49, whereas'Fig. 3 shows the drum in its stopped condition wherein the lug 44 causes the contacts 40, ll. to be closed as above described.

paratus ;have beendisclo'sed herein,' it will be understood that various changes and modificae tions maybemadewithout departing from th 1 40 While certainsp'ecific embodiments andapelectromagnetic means for operating said stop,

means including a' pair of contacts operated when said rotary mechanism is in a predetermined phase, a lowfrequency pulse amplifier; for selec- .tively amplifying said modulations, a rectifier for said-amplified modulations the circuit of said electromagnetic means being controlled jointly by said contacts and said rectified modulations.

5. A phasing arrangement for the rotary mechanism of a telegraph recei machine which is designed to receive a'phasing signal in the form of a' carrier wave having phasing modulations therein at recurrent low frequency spaced intervals, said arrangement including a shiftable stop for engaging said mechanism when out of phase with said transmitter, electromagnetic means for operating said stop, a circuit for energizing said electromagnetic means including a pair of contacts operated by the engagement between said mechanism and said stop, said circuit also including a filter-amplifier whereby substantially only said low frequency signals are amplified and-while substantially suppressing type having rotatable said carrier frequency, and a rectifier for rectifying the output of said amplifier, said rectifier being connected to control saidelectromagrietic means.

6. A phasing arrangement according to-claim 5 ,in which said rectifier is connected to a gridpulse phasing signal to the other member, a

phasing device associated with said other member, and means to render said phasing device automatically effective, the last-mentioned means including a trip magnet, a selective low frequency pulse amplifier whose output controls said mag,-

rotatable signalling devices at remotely located points designed to be operated in time and phase synchronism, means associated with one device controlled gaseous conduction tube having its grid biassed sothat it is triggered ofi to pass plate current undercontrol of said rectified output.

'7. The combination, a rotatable member to be phased with a distant member under control of received phasing impulses, an electromag'net I armature adapted when-normal to engage a 'to transmit a'carrier wave having its amplitude a varied recurrentlyrat low frequency spaced interprojection for stopping said rotatable member, a pair of contacts for controlling said armature. and means carried by said armature and engageable by saidprojection to operate said contacts when the said rotatable member is in a predetermined phase relation.

I 8. In a signalling mechanism, a rotatable memberto be phased with a distant member under control of received-phasing signals, an electromagnet armature adapted to be moved into and out of engagement with a projection moving with said rotatable me'mbena circuit including a pair of contacts controlling said armature; and

a member slidably mounted on said armature and arranged to be operated by engagement with plify a carrier wave modulated in accordance whereby the amplifier amplifies substantially II with signals, a facsimiles'canning drum, power motive means for bringing said drum up to synchronous' speed, synchronous motive means op-v erated under control of said carrier for maintaining said drum at synchronous speed. a. phasing trip magnet for said drum, an amplifier for selectively amplifying a received phasing impulse,

a switch for controlling the circuit to said power motive means, said switch effective in one position to complete said circuit to said power motive means and for applying the said received signals a to said amplifier, said switch in anotherposition breaking said'circu'it to said power motive means and providing a locking circuit for said trip magnet independently of said amplitlen,

AUSTIN G. COOLEY.

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