US3569628A

US3569628A - Frictional drive arrangement for arrangement for effecting phase synchronization of facsimile devices

Info

Publication number: US3569628A
Application number: US803701A
Authority: US
Inventors: Ernest John Okleshen
Original assignee: Magnavox Co
Current assignee: Philips North America LLC
Priority date: 1969-03-03
Filing date: 1969-03-03
Publication date: 1971-03-09
Anticipated expiration: 1988-03-09

Abstract

This invention relates to an improved clutch which is used for effecting synchronous phase operations between two facsimile transceivers. The invention consists of an index gear which is coupled to an electrically operated drive motor in the receiver device and a clutch arm which is frictionally carried with the index gear. The clutch arm carries a pivotally mounted toggle or latch having a detent which is engageable with teeth of the index gear and a second detent which engages a key of a drum in the receiving facsimile device. Synchronization occurs when the detent of the latch engages a correct one of the gear teeth on the index wheel. Electrical signals are provided from the sending facsimile device to effect periodic disconnection of the detent with the teeth of the index gear and also to effect angular displacement of the clutch arm relatively to the index gear until the detent eventually engages the proper gear tooth of the index gear and thereafter the two transceivers operate in synchronous relation, the toggle maintaining a drive connection between the drum and index gear of the receiving unit at synchronized phase orientation of the receiving facsimile transceiver. The present invention is most directly concerned with the means for obtaining the optimum frictional loading between the clutch arm and the index gear which will enable the electrically operated means to perform the necessary adjustments which will eventually achieve synchronization of the sending and receiving transceivers.

Description

United States Patent Primary ExaminerRobert L. Griffin Assistant ExaminerD0naId E. Stout Attorney-Richard T. Seeger no! I ABSTRACT: This invention relates to an improved clutch which is used for effecting synchronous phase operations between two facsimile transceivers.

The invention consists of an index gear which is coupled to an electrically operated drive motor in the receiver device and a clutch arm which is frictionally carried with the index gear. The clutch arm carries a pivotally mounted toggle or latch having a detent which is engageable with teeth of the index gear and a second detent which engages a key of a drum in the receiving facsimile device. Synchronization occurs when the detent of the latch engages a correct one of the gear teeth on the index wheel. Electrical signals are provided from the sending facsimile device to effect periodic disconnection of the detent with the teeth of the index gear and also to effect angular displacement of the clutch arm relatively to the index gear until the detent eventually engages the proper gear tooth of the index gear and thereafter the two transceivers operate in synchronous relation, the toggle maintaining a drive connection between the drum and index gear of the receiving unit at synchronized phase orientation of the receiving facsimile transceiver.

The present invention is most directly concerned with the means for obtaining the optimum frictional loading between the clutch arm and the index gear which will enable the electrically operated means to perform the necessary adjustments which will eventually achieve synchronization of the sending and receiving transceivers.

PATENTED MAR 9 I97! SHEET [3 BF 3 INVENTOR F IG 4 ERNEST J. O'KLESHEN k JEFFEQsHbUmG PATENTEUHAR 9|H7I 3,569,628

SHEET 3 UF 3 INVENTOR F IG 6 ERNEST J. OKLESHEN bq JEFFER$ I Qouwe Afiorrneys FRICTIONAL DRIVE ARRANGEMENT FOR AANGEMENT FOR EFFECTING PHASE SYNCHRONHZATION OE FACSIMILE DEVICIES BACKGROUND OF THE INVENTION In copending application U.S. Ser. No. 520,269, filed Jan. 12, 1966, titled FACSIMILE SYNCHRONIZING SYSTEM," invented by Paul J. Crane and Glenn AI Reese, now U.S. Pat. No. 3,505,472 and assigned to the same assignee as the present invention, there is disclosed a synchronizing system for effecting an in-phase operation between a sending and receiving facsimile device respectively.

In order for the operation of .a pair of a sending and receiving transceivers to operate properly, the scanned information of the material being transmitted in the sender transceiver should be printed out at the same relative position on the copy material of the receiver unit with which it is operating. This necessitates a synchronizing of the two units whereby scan and printout occurs at matched positions. ln the referenced copending application Ser. No. 520,269fthere is illustrated a general system for effecting in-phase operation of the sending transceiver and the receiving transceiver wherein an electrical signal is periodically transmitted from the sending transceiver which indicates the position of the scanner portion of the sending transceiver. The signal which is received, is utilized by the receiving transceiver to effect synchronization with the "sending transceiver .so that printout of information at the receiver will occur =.at a position which is matched with the ,position of that same information on the document or other article being scanned in the sending transceiver.

Briefly, synchronization of the receiving unit with the send ing unit is-obtained by means of a first and second drive path between a constant speed electrical motor and the yoke or mechanical printout portion in the receiver unit. The second drive path provides a speed of yoke rotation identical to that .of the sending unit. The first drive path provides yoke rotation at a reduced speed. The second drive path consists of an index gear having a number of teeth on its outer periphery any one of which may be operatively and mechanically coupled to a .drum which in turn operates the yoke or printout portion of the receiver. When the two transceiver units are in proper phase or synchronization, the index gear is at a preferred an- .1 gular position with respect to the drum'or yoke.

l The second drive path is obtained by coupling any one of the teeth of the index gear to the drum by means of a toggle carried by a clutch arm which is frictionally carried with the index gear, thereby providing yoke'rotational speed identical to that in the transmitting unit. When the toggle is decoupled from the index gear, the first drive path, which provides reduced rotational speed of the yoke, is operative. Decoupling of the index gear from the drum by means of the toggle and subsequent recoupling will provide a slightly different angular relationship between the index gear and the drum and thus between the drive motor and the yoke and its printout means.

The toggle is activated, and thus coupled and decoupled, by means of a solenoid arrangement which receives synchroniz- 'ing signals or pulses from the transmitting unit. During the initial synchronization time period, the yoke or printout means is alternately coupled to the constant speed motor by first one drive means and then the other. if the two units are not in proper synchronization, this alternately coupling and decoupling will cause the receiver drum and the yoke and printout means to gradually retrogress to a position identical to that of the transmitter drum or yoke at which time the two units will be in synchronization or properly framed and further gear relatively to the drum is subject to certain imprecise limitations. For example, the actuatable toggle coupler between the indexagear'and thedrum must be responsive over a relatively short period of time as determined by the synchronizing pulses Als'o, l have found that the coupling means between the index gear and the drum, may be carried on a clutch arm which when frictionally carried with the index gear provides a much more reliable synchronizing operation. I have found that a lack of such friction or an uncontrollable or excessive amount results in unreliablesynchronization or no synchronization at all. As will be later apparent, such excessive and uncontrollable degrees of friction can result in detrimental operation of the synchronizing means and/or damage to the component parts of the system. For example, should there be excessive friction between the clutch arm and the index gear, the electricallyenergized actuating means which produces decoupling, cannot properly decouple the clutch arm relatively to the index gear and hence is not able to properly engage a new gear tooth upon being recoupled and in addition can cause forced binding or bending of the clutch arm and its toggle with the solenoid activating mechanism which can result in 'd eformation of the'toggle and/or activating mechanism. If on the other hand, for example, friction is lacking or is insufficient, then excessive slippage occurs between the clutch arm and the index gear and synchronization will not take place within the allotted time or will not occur at all. I have found that a controllable amount of friction provides a much improved and consistent synchronization operation and is much less critical with regard to operating parameters and environments as well as wear of the component mechanical parts of the system. i

OBJECTS OF THE lNVENTlON It is an overall object of the present invention to provide a new and improved synchronizing device which will .effect inphase operation of sending and receiving transceivers and will .do so consistently within the time allotted for synchronization to take place. Consequently, occurrence of misframing is minimized because synchronization is more conveniently and reliably obtained.

It is a further object of the present invention to provide a novel clutch mechanismfor use in synchronizing a sending and a receiving facsimile device in which the frictional forces are precisely obtained and are maintained at the preferred value throughout the operation of the device whereby synchronizing operation of the device may be more effectively and efficiently performed.

A still further object of the present invention is to provide an improved clutch device in a synchronizing mechanism, which utilizes a friction drive in which the mating materials are of dissimilar metals which will resist galling, seizing, and other objectionable variations during the useful life of the clutch. By providing an improved frictional clutch drive, it is possible to obtain synchronous operation of two facsimile devices which are brought into in-phase operation and such results obtained consistently'and well within the period allotted for such synchronization.

It is a further object of the invention to provide reliable framing of facsimiles each time the machine is operated and regardless of environment of use during the useful life of the machine.

A further object of .the invention is: to effect synchronous operation by increments of synchronization adjustments which are independent of operational parameters and are substantially equal in each successive adjustment until final synchronization is obtained.

A further object is to obtain synchronization by means of-a device having rugged components which are not mechanically deformed during use and require minimal adjustments. Consequently the operation is not only consistent from one machine to the next but also has minimal wear and deterioration under use to maintain that consistency of operation.

To the extent that wear of the synchronizationi adjuster parts occur, such wear has no appreciable effect on the ope'i'ation of the machine. i 3

DESCRIPTION OF THE DRAWINGS FIG. I is an isometric view of a transceiver facsimile device described in this disclosure as a receiving unit and which is intended to be brought into synchronized operation with a second facsimile device which acts as a sender;

FIG. 2 is a sectional view of the clutch mechanism taken along the section 2-2 of FIG. 1;

FIG. 3 is an isometric view of the clutch arm illustrated in FIG. 2;

FIG. 4 is a side elevation view of a portion of the mechanism of FIG. 2 looking in the direction of the arrows 4-4 of FIG. 2;

FIG. 5 is an enlarged isometric view of the spring washer used to effect frictional loading on the friction coupling between the clutch arm and index gear;

FIG. 6 is an exploded isometric view of the clutch mechanism gears forming a two-path drive system between the motor of the receiving transceiver and drum; and,

FIG. 7 is an enlarged detail view of the toggle and toggleoperating mechanism which is activated by signals obtained from the sending transceiver.

SPECIFIC EMBODIMENT Referring to the drawings in more detail and especially to FIG. 1, the present invention is embodied in a facsimile transceiver 10 for producing facsimiles of original documents such as letters, photographs, drawings, or blueprints. Although the facsimile transceiver may employ any type of transmission line, it is particularly adapted for transmitting the facsimile signals over a conventional telephone transmission line. The transceiver 10 has a base 12 upon which the various operating portions are mounted. A semicylindrical platen (not shown) is mounted on the base 12 to extend thereacross. When the transceiver is operating in a receive mode, a driving motor 14 is initially energized upon receiving a signal from the sending transceiver. The motor 14 uses a precisely generated AC input and runs at a constant speed that is controlled by the frequency of the AC input or driving power. Thus, the opticalscanning means of the sending unit and the printing transducer of the receiving unit will rotate at the same angular velocity. However, to maintain the necessary registry or framing between the facsimile printed by the receiver and the original document scanned by the transmitter, the rotational position with respect to the document of the optical-scanning means in the sending transceiver must be synchronized with the position of the printing transducer of the receiving transceiver. More particularly, each time the optical-scanning means initiates a scan across the document, the printing transducer should undergo a corresponding scan across the copy paper.

The motor 14 acts through a speed reducer l5 and operates a power shaft having a two-path gear drive system which rotates drum 30. The drum is in turn coupled mechanically to a yoke 24 which operates a printing transducer 26.

The first drive gear path between power shaft 20 (FIG. 4) and drum 30 comprises gear 32 (FIG. 6) secured to shaft 20 by screws 33. The gear 32 is coupled to a transfer gear 34 through a pinion gear 36 mounted on shaft 38 which is received in an opening 40 at base 42 of the drum 30. Transfer gear 34 is couple through a pinion gear 44 to a clutch governor 48 having spring-loaded braking shoes 50 which are received within a clutch sleeve 52. formed integrally with drum 30. The sleeve has an interior cylindrical surface engageable by shoes 50 which extend radially outwardly frictionally against the sleeve to form a connection with drum 30 thereby providing a driving gear path between motor 14 and power shaft 20 to drum 30. The friction developed between the shoes 50 and sleeve 52 of the clutch governor 48 causes the governor and

gear train

44, 34, and 36 to precess about gear 32 and the net overall effect is to cause the drum 30 to rotate at a reduced speed in relation to the rotational speed of power shaft 20. This reduction in drum Speed is controlled by the

gear train

32, 36, 34 and 44 and the frictional braking characteristics of the clutch governor 48.

The second drive gear path between power shaft 20 (FIG. 4) and drum 30 comprises index gear 66 and toggle 68 mounted on arm 72 which in turn is mounted coaxially on power shaft 20 to rotate about the same axis of rotation either with or relatively to the shaft 20. This second path provides a direct drive between the power shaft 20 and the drum 34 by means of the detenting action of the toggle 68 with any one of the teeth 62 of index gear 60 and key 75 on drum 36) as is illustrated in FIG. 2.

The power shaft 20 has connected to it (FIG. 4) by screws 33 an index gear 60 separated from gear 32 by a spacer 66, with a number of gear teeth 62, the index gear 60 being positively driven by the motor from the speed reducer 15. Index gear 60 is coupled to drum 30 through a toggle 68 (FIG. 2) having one detent 70 which engages gear teeth 62 of index gear 60 and a second detent 71 engages a key 75 operatively connected to drum 30. The toggle 68 is mounted on a clutch arm 72 through pivot mounting 74 so that the toggle 68 can be pivoted causing

detents

70, 71 to be either in the position shown in FIG. 2 or pivoted counterclockwise to the position shown in FIG. 7 wherein the detents are disengaged from gear teeth 62 and key 75. The toggle 68 is biased to the position shown in FIG. 2 by means of a spring 78 which is stretched between a finger 80 of a clutch arm 72 and a depending finger 82 of toggle 68.

When the transceiver units are initially activated the receiver drum 30 is coupled to the power shaft 20 by means of the second drive path. This then provides drum and yoke rotation at, a speed identical to that of the transmitting unit; however, there is required a framing or synchronizing operation as previously mentioned prior to any printout of the facsimile copy by the receiver unit.

There is received from the sending transceiver, an interrupted synchronizing signal which is transmitted to synchronizing clutch actuator indicated in FIG. 7, this signal being effective to energize solenoid and effect a positioning of pawl 92 to the solid line position illustrated in FIG. 7, the pawl being pivoted about 94 so that end 96 of pawl 92 is in position to engage a toggle pin 98 of toggle 68 so that as the toggle 68 rotates past end 96, as shown in FIG. 7, it will be pivoted from the position shown in FIG. 2 to the position shown in FIG. 7 and thereby disengaging each of the

detents

70, 71 from operative engagement with gear teeth 62 of the index gear 60 and key 75 on drum 30. The synchronizing signal obtained from the sending transceiver is interrupted twice each revolution of the index gear 60 and during the times of such interruption a stretched spring 100 connected to pawl 92 through opening 102 and flange 104 of bracket 106 will pivot the pawl 92 to the dotted line position shown in FIG. 7 wherein face 108 engages a threaded adjustable stop III. When the sending and receiving transceivers are synchronized and in phase operation, the synchronizing signal will be interrupted at precisely the time the drum rotates the toggle to the position of FIG. 7 where the toggle pin 98 would otherwise be engaged by the pawl 92. That is to say, when synchronization is achieved the synchronizing signal is interrupted at the time and for the duration necessary to permit the toggle pin 98 to move past the pawl 92 so that the position of the toggle 68 is maintained continuously coupled as shown in FIG. 2 with the index gear teeth 62 maintaining a drive connection with the drum 30. Thus, at synchronization the motor M drives drum 30 continuously through the index gear 60 through the toggle 68.

Until synchronization occurs, the toggle pin 98 will be engaged by the pawl 92 each revolution of the drum 30 thereby disengaging the toggle detents 70, 7i and separating the drive connection between the index gear 6!) and drum 30 and simu taneously with such separation or unlatching there will be a slight angular adjustment of the clutch arm 72 with respect to the gearwheel 66 so that the detent 70 can engage a different one of the gear teeth 62 until a proper one of the gear teeth is engaged which will couple the index gear wheel 66 and drum 30 in a manner effecting synchronization.

Theangular adjustment described is obtained by means of a friction coupling at the hub 110 of clutch arm 72 (FIG. 3). The friction coupling includes a bushing 112 composed of bronze composition or other suitable friction material which may be press-fitted within an opening lldthat provides a friction face 116 which bears against a confronting surface 120 of index gear 60. The two confronting

surfaces

116 and 120 provide friction drive coupling between the index gearwheel and clutch arm, the said two surfaces being forced together by means of a wave or spring washer 140 which bears against a shoulder146 of the drive shaft 20 and surface 150 of clutch arm 72. The two

surfaces

116 and 120 are thus urged together with a constant normal force which is substantially equal throughout the area of the confronting surfaces and the normal loading does not change appreciably during the useful life of the device. The constancy of this frictional coupling, results to the uniformity of friction loading developed by wave washer 140 which develops a uniform normal force around the, periphery of surface 116 and the value of this normal loading does not change appreciably duringuthe useful life of the device. Also, because of the composition of the bushing 112 there is relatively little or no seizing or galling between the friction surfaces 116 and 120 of bushing 112 and index gear wheel 60.

It has been found, that for optimum synchronizing adjust- I ments by the clutch arm 72, the friction couplingrbetween the clutch arm 72 and index gear 60 must be of a value satisfying two distinctly different criteria: (1) Should excessive friction be developed in the coupling between arm 72 and index gear 60the pawl 92 (FIG. 7) will be unable at the time of its engagement with the toggle pin 98 tohold the clutch arm back relatively to the index gear 60 to effect an adjustment wherein detent 70 engages different gear teeth 62 of the indexgear60 and (2) if the friction developed is too small then the force will be insufficient to enable the clutch arm to remain coupled with the rotating index gear.

With the present invention, in onespecific embodiment utilizing wave washer spring 140 and bushing 112 it is possible to obtain the correct frictional coupling between the clutch arm 72 and the index gear 60 so that during each revolution of the index gear 60, the pawl 92 will effect a resetting of approximately three teeth 62of index gear 60 until the detent 70 reaches a proper position which will provide synchronization. Considering the rotational speed of the gearwheel and the maximum adjustment needed, there will be a sufficient number of the adjusting operation so that inevitably, even in the most extreme situation, the detent 70 will be caused to drop within the correct gear tooth within thetime allotted for obtaining synchronization, which is in the order of about to seconds after which time the receiver facsimile machine will commence printing whether or not proper synchronization has been achieved, and it therefore becomes of considerable importance to the proper operation of the two transceivers that synchronization will occur in every instance within the allotted time, which the present invention can accomplish.

As used hereinbefore, the terms synchronization" and inphase are meant to include that condition of operation of the receiver and the sender transceivers wherein thescanning occurs at the same relative location on the document as the printing transducer effects printing on the document within the receiving transceiver. For an even fuller explanation of how this isachieved, and for a more complete definition of synchronous in-phase operation, reference may be made to application Ser. No. 520,269 before referenced, which will describe in greater detail the structural and functional background of the entire facsimile device.

During the synchronization when the drum rotation is coupled from the second drive path means to the first drive path means (reduced speed) a slip clutch spring 170 (FIG. 6) provides cushioning of any sudden motion or rotation developed between the governor 48 and the gear 36 which allows dissipation of energy stored in the governor and thus prevents damage to the associated first drive path gear train and the governor.

The synchronizing signal from the transmitting unit deenergize the solenoid twice during each revolution of the drum in the sending transceiver to permitthe pawl 92 to be positioned in the dotted line position FIG. 7, this being obtained by magnetic reed switches (not shown) which are mounted on the main frame of the scan-print module that are located approximately 90" apart! Magnets which operate these reed switches are located in the outer rim of the synchronizing clutch drum and are 180 apart, producing two scans for each revolution of the yoke.

OPERATION OF THE DEVICE In operation, when the send transceiver is activated, the

motor 14.0f the sending transceiver immediately starts rotation of the associated drum through the toggle connection provided between its index gear and thedrum thereby driving the yoke and the optical scanning means at operational speed.

The sending transceiver transmits an interrupted synchronizing signal to solenoid 90.inthe receiving transceiver which when energized, pivots thepawl 92labout pin 94 against theresistance of spring to the solid line position shown in FIG. 7 and during periodic deenergization, spring 100 rotates the pawl 92 about pivot 94 to the dotted line position wherein surface 108 engages the stop 111. The position of the stop defines the dotted line position for'the pawl effected by spring 100. When the pawl 92 is'in this dee nergizedposition, the

index gear 60 and drum 30 are directly coupled together (second drive path).by means of the toggle 68 with its corresponding

detents

70, 71 engaging the respective index gear teeth 62 and the latch or key 75 on drum 30 as is illustrated in FIG. 2. When the index gear 60, clutch arm 72, and toggle 68 rotates substantially to the position illustrated in FIG. 7, and

the solenoid 90 is in the energized condition, the surface 96 of pawl 92 will engage pin98 of the toggle and cause the

toggle detents

70, 71 to be disengaged from the index gear and drum thereby providing rotation of the drum by means of the first or reduced speed drive path as previously described.

At startup, the motor 14 of the receiving transceiver may be out of phase with respectlto the sending transceiver thus resulting in initial out of phase rotation of the drum .30 being driven by the second gear train through the power shaft 20. Synchronization takes place by alternately coupling the drum through the first and'second drive paths by means of the synchronizing signals acting on the solenoid 90 and its pawl mechanism as heretofore described. Synchronization occurs when 70 engages a proper one of the teeth 62 on the index gear. This adjustment of the toggle 68 will be achieved by. means of the present invention within the time period allotted for synchronizatiori which is between 15-20 seconds or so before the sending transceiver and the receiving transceiver .commence scanning and printing operations. Once detent 70' of toggle 68 enters the correct tooth of the index gear 62 it maintains its proper position by means of the operation of pawl 92 which is operated by solenoid 90.

Solenoid 90 is responsive to an interrupted synchronizing 0 signal from the sending transceiver. So long as the synchronizing signal is not interrupted, the pawl 92 will be in the solidline position shownin FlG. 7 and will engage toggle pin 98' during each revolution of 'the index gear 60, thereby pivoting toggle 68 about its mounting pin connection 74 with clutch arm 72 and pivoting the toggle 68 from the position shown in FIG. 2 to that of FIG. 7. The

detents

70, 71 arebrought out of engagement with the gear teeth 62 of the index gear and key 75 of the drum 30." Simultaneously with such pivoting about" pivot pin 74 the clutch arm 72 will be moved angularly with" respect to the index gear 60 against the resistance of the fric tion coupling between the clutch arm 72 and the index gear, 60. The friction coupling is constituted by a bushingr112 having a face 116- which is pressed against surface 120 of the: index gear andis held in that position by means of a waveor spring washer clamped between side of the clutch arm and shoulder-1416. The frictional force remainsrelativelyt constant ,throughoutthe wear life of the device and the fric=- tion surface is not deteriorated by use. The frictional coupling is of such value that it can be overcome by the retarding force developed by pawl 92 engaging pin 98 of toggle 68 so that relative movement occurs between the clutch arm and the index gear. After the solenoid signal is interrupted and the solenoid disengages pin 98, the clutch arm resumes rotation with the index gear 60 first in a new selective position so that the spring 78 will cause detent 70 to enter a new gear tooth 62 of the gear wheel 60.

Should this be the proper gear tooth of index gear 60 to effect in-phase operation of the receiving transceiver relatively to the sending transceiver, then at the next revolution of the clutch arm 72 and index gear 60, the pin 98, at precisely the moment it comes into position for reengagement with the pawl 92, the synchronizing signal from the sending transceiver will be interrupted and the pawl 92 will be rotated to the dotted line position by a spring 100 and the pin 98 will move past the pawl without engaging therewith thus enabling the detent 70 to remain in engagement with a correct one of the gear teeth 62 of index gear 60 which will produce an in-phase relationship of the receiving transceiver. A continuous drive connection is maintained between the index gear 60 and the drum 30 since the toggle 68 is continuously maintained in the position shown in FIG. 2 wherein the detent 70 and detent 71 provide a continuous coupled relation between the index gear and the drum 30 through the toggle 68. The spring 78 is used to maintain the toggle 68 in its driving position.

For optimum results, synchronization should occur in the shortest possible period and it has been found that this goal is achievable by obtaining a proper friction coupling between the clutch arm 72 and the index gear 60 which will permit the toggle 68 to be angularly displaced with respect to the index gear 60 in a reliable manner to effect angular adjustment between the detent 70 and the gear teeth 62 of the index gear 60, care being taken that the friction is not so excessive as to be greater than the impact force developed by the pawl 92 in engaging pin 98 to preclude adjustments from taking place, and also not so slight that impact of pawl 92 against pin 98 will cause racheting of the detent 70 so it could move past the correct gear tooth 62. The correct amount of friction can be obtained by means of the present invention which combines a preferred loading of the friction coupling between the clutch arm 72 and the index gear 60 at the hub of the clutch arm, such loading being obtainable reliably and consistently by means of the wave or spring washer 140 and also by obtaining a consistent coefficient of friction between the mating surfaces 120 and 116, by means ofthe bronze bushing 112.

Although the present invention has been illustrated and described in connection with a single example embodiment, it will be understood that this is illustrative of the invention and is by no means restrictive thereof. It is reasonably to be expected that those skilled in this art can make numerous revisions and adaptations and it is intended that such revisions and adaptations will be included within the scope of the following claims as equivalents of the invention.

Iclaim:

1. In combination in a facsimile system for effecting phase orientation between the operations of a transmitting and receiving pair of facsimile devices each having a rotatable drum adapted to revolve about its axis, a first electric motor operatively connected to its associated drum in the transmitting facsimile device for rotation thereof, a second electric motor operatively connected to an associated second drum in the receiving facsimile device for rotation of such drum at the same angular velocity as said first named drum and in phase orientation therewith, and a clutch mechanism for effecting a drive connection between said second electric motor and its associated drum which is responsive to electrical signals from said transmitting device to effect synchronous phase operation between said devices, said clutch mechanism comprising a rotatable arm, toggle means pivotally connected on said arm and having two spaced detents and a toggle pin, indexing gear mea ns coupled to the output of the motor in said receiving facsimile device and having gear teeth adapted to receive one of the detents of said toggle means, friction drive means forming a drive connection between said arm and said indexing gear means, a key on said second drum operatively engageable by the other detent of said toggle to provide a drive connection between said indexing gear means and said drum, electrically operable means responsive to electrical signals from said transmitting facsimile device for engaging said toggle pin at nonsynchronized phase operations between said devices and thereby disengaging said detents from said key and index gear teeth respectively and to effect relatively angular movement of said clutch arm relative to said indexing gear means whereby said detent engages with other gear teeth of said indexing gear means until such detent engages index gear teeth forming a drive connection with said drum wherein said facsimile devices are synchronized in phase operation, said friction clutch means being constituted by axially relatively movable confronting surfaces provided by said clutch arm and said indexing gear means, and a resilient member axially biasing such confronting surfaces to develop a rotational frictional force less than the retarding effect developed by engagement of said toggle pin and said electrically energized means.

2. The structure in accordance with claim 1 wherein said resilient member is constituted by an annular member having an irregular surface, and means for clamping said resilient member in a deformed position for biasing such confronting surfaces of said clutch arm and index gear together.

3. The structure in accordance with claim 1 wherein the confronting surfaces provided by said clutch arm and said index gear are of nonseizing dissimilar materials.

4. The structure in accordance with claim 1 wherein said resilient member develops a frictional force retarding relative rotation of said clutch arm and said indexing gear means sufficient to carry said toggle means past its point of engagement with said electrically energized means to preclude ratcheting of the detent with respect to the teeth on said index gear.

5. An improved clutch mechanism for use in synchronizing devices for facsimile machines adapted to be synchronized in their sending and receiving operations, said clutch comprising a clutch arm having a hub, a friction material liner operatively connected to said hub, an index gear having a plurality of gear teeth at the outer periphery thereof, and a hub portion of said gear confronting the liner of said clutch arm and in frictional engagement therewith, annular means having reversely bent resilient portions forming a gently corrugated washerlike spring, and means for clamping confronting surfaces of said liner and index gear together against the resistance of said annular resilient means to effect a preferred frictional resistance to angular movement therebetween, and coupler means operatively carried by said clutch arm and having an operative engagement with the teeth of said gear and a further connection to provide a drive connection between said index gear and a member driven thereby, said clutch arm being angularly movable together with said coupler means relatively to said index gear to effect phase orientation operation.

6. The structure in accordance with claim 5 wherein said liner is of a preferred coefficient of friction material and is both nonseizing and nongalling with respect to the opposing surface of said index gear.

Claims

1. In combination in a facsimile system for effecting phase orientation between the operations of a transmitting and receiving pair of facsimile devices each having a rotatable drum adapted to revolve about its axis, a first electric motor operatively connected to its associated drum in the transmitting facsimile device for rotation thereof, a second electric motor operatively connected to an associated second drum in the receiving facsimile device for rotation of such drum at the same angular velocity as said first named drum and in phase orientation therewith, and a clutch mechanism for effecting a drive connection between said second electric motor and its associated drum which is responsive to electrical signals from said transmitting device to effect synchronous phase operation between said devices, said clutch mechanism comprising a rotatable arm, toggle means pivotally connected on said arm and having two spaced detents and a toggle pin, indexing gear means coupled to the output of the motor in said receiving facsimile device and having gear teeth adapted to receive one of the detents of said toggle means, friction drive means forming a drive connection between said arm and said indexing gear means, a key on said second drum operatively engageable by the other detent of said toggle to provide a drive connection between said indexing gear means and said drum, electrically operable means responsive to electrical signals from said transmitting facsimile device for engaging said toggle pin at nonSynchronized phase operations between said devices and thereby disengaging said detents from said key and index gear teeth respectively and to effect relatively angular movement of said clutch arm relative to said indexing gear means whereby said detent engages with other gear teeth of said indexing gear means until such detent engages index gear teeth forming a drive connection with said drum wherein said facsimile devices are synchronized in phase operation, said friction clutch means being constituted by axially relatively movable confronting surfaces provided by said clutch arm and said indexing gear means, and a resilient member axially biasing such confronting surfaces to develop a rotational frictional force less than the retarding effect developed by engagement of said toggle pin and said electrically energized means.