US2646335A

US2646335A - Facsimile apparatus

Info

Publication number: US2646335A
Application number: US14293A
Authority: US
Inventors: Raleigh J Wise; Robert D Parrott
Original assignee: Western Union Telegraph Co
Current assignee: Western Union Telegraph Co
Priority date: 1942-08-14
Filing date: 1948-03-11
Publication date: 1953-07-21
Anticipated expiration: 1970-07-21
Also published as: BE471309A; FR988008A

Description

July 21, 1953 R. J. WISE ETAL FACSIMILE APPARATUS 2 Sheets-Sheet 2- INVENTORS R. J WIS E lllllvlllulll muamoumm l Original Filed Aug. 14, 1942 0 ON m mm NN R. D. PA R ROTT ATTORNEY Patented July 21, 1953 FACSIMILE APPARATUS Raleigh J. Wise, Arlington, and Robert D. Parrott, West New York, N. J., assignors to The Western Union Telegraph Company, New York, N. Y., a corporation of New York Original application August 14, 1942, Serial No. 454,768, now Patent No. 2,469,423, dated May Divided and this application March 11,- 1948, Serial No. 14,293

7 Claims.

This invention relates to facsimile systems, and has particular reference to apparatus employed for the mounting and supporting of a flexible sheet for scanning purposes.

This application is a division of application Serial No. 454,768, filed August 14, 1942, now Patent No. 2,469,423, issued May 10, 1949.

In order that the advantages of facsimile communication be made available as widely as possible, it is necessary to provide scanning apparatus which is relatively simple. In this manner such apparatus may be operated by persons who are not especially trained for the purpose. One drawback to the general use of prior art apparatus is that some degree of skill is usually I required on the part of the operator. In appachanical complications.

Accordingly, it is the principal object of the present invention to provide a relatively simple and novel facsimile scanner for operation by an unskilled person.

Another object of the invention is to provide novel means for securing a flexible sheet to a cylinder for scanning purposes.

Still another object of the invention is to provide expansible means for supporting a flexible sheet on the inside of a hollow cylinder or tubular member;

A further object of the invention is to provide for the securing of a flexible sheet to the inside of a hollow cylinder by means of an expansible helical member.

A still further object of the invention is to provide for the securing of a flexible sheet to the inside of a hollow cylinder by means of a plurality of centrifugally actuated members.

An additional object of the invention is to provide a facsimile machine with a novel cover for the scanner, the cover having means for being releasably locked in a closed position.

Another object of the invention is to provide, in a facsimile machine, novel means for actuating contacts by the movement thereof to intercept and stop a normally moving operating member.

These and other subsidiary objects of the invention are embodied in an illustrative embodiment thereof which will be described in connection with the accompanying drawings, of which:

Fig. 1 is a partial front elevation and sectional 2 view of the sheet mounting apparatus and the control mechanism therefor;

Fig. 2 is a fragmentary sectional view taken on the line 2--2 of Fig. 1;

Fig. 3 illustrates the manner of forming the sheet for insertion in the supporting cylinder; and

Fig. 4 is a schematic circuit diagram showing one way of controlling the operation of the facsimile transmitter.

The invention is embodied in a machine which is designed so that it may be used in any business ofiice or similar place. The sheet bearing the subject matter to be transmitted, after being roughly formed into a loose roll, is inserted through the top of the machine into a rotatable hollow transparent cylinder or tubular member. A cover is moved to close the opening, and a handle attached to the cover is actuated to start the machine whereby to transmit a signal to the recording station. The handle is then locked in this position for the duration of the scanning operation so that it is impossible to open the cover. As soon as the machine is put into operation, expansible means within the hollow cylinder operate to press the sheet firmly against the inside of the cylinder wall. A carriage, upon which is mounted optical scanning apparatus, is then moved longitudinally of the rotating cylinder whereby a, helical scanning of the subject matter on the blank is effected. Following the scanning operation the cover handle is unlocked so that the cover may be moved to again provide access to the inside of the cylinder, which at this time is no longer rotating. The expansible means within the cylinder is also withdrawn from engagement with the sheet so that it may be removed and replaced by another, if desired, and the entire sequence repeated.

In the embodiment of the invention disclosed herein the exp-ansible means comprises a helical spring-like member mounted within the hollow cylinder and connected to mechanism whereby, when the cylinder is at rest, the helical member is wound tightly about a spindle extending through the cylinder substantially coaxially therewith. This helical member is tensioned in such a manner that, when the cylinder is released for rotation, the helical member unwinds from the spindle unti1 it presses the paper against the inside of the cylinder wall.

Fig. 1 shows details of the inner construction of the machine and Fig. 4 illustrates, 'at station A, the general exterior form thereof. The machine is supported by a base l5, Fig. 4, from 3 which there extends upwardly a cover or casing l6, Fig. l. Toward the top of the machine is an opening leading into a transparent hollow cylinder or tubular member 4|. The opening i normally closed bya cover 2| which is provided with a handle 22 pivoted thereon, as seen in Fig. 4 at station B, so that it may be depressed when the cover is in its closed position to move a handle 3 rod or switch operating member 23, bymeans of which the machine is started. Formed in the front of the cover I 6 is a window 24, seen at station A, through which may be viewed the transparent cylinder and a sheet 25, Figs. 1 and 3, mounted therein.

Having reference to Fig. 1, the sheet mounting and scanning apparatus will be described in greater detail. This apparatus is supported between an upper plate 21 and a lower plate 28 in the upper part of the machine housing. The lower part of thehousing is used for the auxiliary apparatus, such as a power pack, amplifier, control relays, etc. The lower plate 28 is attached by means of angle irons, such as 3| to the casing IS. The upper plate 21 is supported by thelower plate and spaced therefrom by rods such as 33. An intermediate bearing plate 35 has formed adjacent the edges thereof a plurality of bosses such as 36, by means of which the bearing plate is attached to the rods such as 33.

The apparatus 3'! in which the subject matter bearing sheet is supported for scanning comprises a base 38 secured to a shaft 39' and also a transparent hollow cylindrical or tubular section 4| extending upwardly from the base. The transparent cylinder wall may be made of glass or any equivalent material such as a transparent plastic. The top of the transparent cylinder 4| is capped by a ferrule 42 which is free to rotate in an opening 43 formed in the upper plate 2?. There is no connection between the ferrule and the plate 21.

The shaft 39, upon which is supported the apparatus 31, is journaled in the bearing plate 35 and the lower plate 28. Secured to this shaft is a worm wheel 44 which meshes with a worm 45 mounted on the shaft of a driving motor 46.

Thislinkage serves to rotate the sheet mounting apparatus 3'! upon operation of the motor 46.

The optical scanning apparatus is mounted on a carriage 41, diagrammatically indicated in Fig. 4, which carriage is attached to an elongated sleeve member 48, Fig. l, which is adapted for vertical sliding movement on a guide rod 49. This rod is supported at its upper end in the plate 21 and at its lower end in a bracket which is mounted in spaced relation above the plate 28. A lamp 52, Fig. 4, is mounted in a bracket (not shown) which is attached to one side or flange of the carriage 41. Light from the lamp is directed by a condensing lens tube, also mounted on the flange, so that a small spot of light is focused upon a subject matter bearing sheet mounted within the transparent cylinder 4|. Light which is reflected from the surface of the sheet is directed by a pickup lens tube, also mounted on the flange, onto the responsive element of a photoelectric tube 51 which is mounted on another flange of the carriage 41. Supported between the two flanges of the carriage is a small electric motor |59, upon the shaft 59 of which is carried a light chopper disc 6| which is provided adjacent its periphery with a series of notches. The disc is positioned with respect to the reflected pencil of light so that, upon rotation, the light which is directed toward the photoelectric tube 51 is periodically interrupted to produce in the output circuit of the photoelectric tube a series of unidirectional impulses, the amplitude of which represents the tonal value of the elemental areas of the subject matter being scanned.

' The sleeve member 48, Fig. l, is provided ad- ,jacent its lower extremity with two spaced collars "B2 and 83, between which there is supported a ring-like member 64. The ring 64 is free to rotate about the axis of the member 48 and carries an arm on which is mounted a half-nut 89 that is adapted for engagement with'a feed screw '6? under control of an electromagnet 13.

The feed screw is journaled for rotation in the

plates

21 and 28 and has attached adjacent the lower end thereof a gear 15, Fig. 1, which is meshed with a gear -19 attached to the shaft 39'.

-Upon operation of the motor 45, the feed screw B'Lis rotated at a predetermined speed so that, when it is engaged by the half-nut 66, the carriage 41 is moved downward for scanning purposes at a prearranged rate.

Upon completion of a scanning operation, the half-nut is disengaged from the feed screw, and the carriage is returned to its upper position by means of a spring (not shown) or other suitable retractive force. The spring is attached at one end to the carriage and at the other end to any other convenient stationary member, such as the upper plate 21. A rubber or other suitable shock absorbing stop (not shown) is attached to the upper plate 21 in a position to be struck by the carriage 41 when it is returned to its normal idle position.

The cover 2| which is hinged at 84 is adapted to. close the opening 43 in the upper plate 21 when in the position illustrated in Figs. 1 and 4, and when raised upwardly, affords access to the interior of the transparent cylinder 4|. A channel member 85 is attached to the top of the cover 2|, and pivoted therein at 89 is the handle 22. The handle is normally held in the position shown by a spring (not shown). Adjacent the free end of the handle is the depending rod or switch operating member 23 which extends through an opening 9| formed in the upper plate 21. A collar 92 is formed adjacent the lower extremity of the rod 23 for a purpose to be described. When the cover 2| is in its closed position, a downward movement of the handle 22 brings the lower end of the rod 23 into position to actuate a rod i23 and close a pair of contacts 93 which are used for a control purpose to be described. With the handle in such an operated position, a forked member 94 may be moved to the left, as viewed in Figs. 1 and 4, by the energization of an electromagnet 95 and slipped over the top of the collar 92 so that the handle is retained in this position. If the electromagnet 95 is energized before the handle is depressed, the formed member 98 is in a position to intercept the collar 92 before the rod 23 can be moved sufiiciently to close the contacts 93. V

The cover 2| has formed therein adjacent the hinge 84 a cam surface 96. A cam follower 97 is for the purpose of operating a pair of contacts 99. The cam surface 96 is so shaped that, when the cover 2| is in its closed position as shown, the cam follower is in its lower position to close the contacts 99. When'the cover 2| is moved to the position shown by the dotted lines, the cam follower 91 is permitted to move upwardly and to thereby open the contacts 99.

In Fig. 3 the manipulation necessary to insert a sheet in the cylinder is shown. The sheet 25 is roughly formed into a loose roll as shown and placed within the cylinder until the lower edge of the sheet reaches the bottom of the cylinder. It is not even necessary to retain the illustrated grasp of the sheet until this operation is com pleted for the reason that, once the sheet is well within the cylinder, its roll form is retained by the cylinder itself. The insertion operation may then be completed simply by pressing with the palm of the hand upon the upper edge of the sheet until it is completely within the cylinder.

Referring to Fig. 1 it will be noted that the shaft 39' is hollow and is secured to the base 38 of the cylinder M so that, upon rotation of the shaft, the cylinder is also rotated. A retaining member IE9 in the form of a wire having resilient properties is placed within the cylinder in the form of a helix. One end of the helical wire is attached by means of a screw III to the base of the cylinder, and the other end is attached by means of a screw H2 to the protecting cap I03.

In this case the cap 108 is secured to a shaft H3 which is mounted inside the hollow shaft 39' and is free to rotate therein. The lower end of the shaft H3 extends beyond the end of the hollow shaft 33 and has secured thereto a peripherally grooved collar I54. Mounted within the groove of' the collar is a circularly formed member II 5, one end of which is bent outwardly to form stop arm H6. The circular member H5 is not rigidly secured to the collar H4, but it is the contact springs I22 is in position to intercept the stop arm HS mounted on the shaft H3. The contact structure II'i, however, is adapted to be pivoted counterclockwise as viewed in Fig. 1 so that the contact spring I22 takes the position shown in broken lines and allows the stop arm H6 to rotate unimpeded. A rod I23 extends from the contact structure I IT to a point adjacent the underside of the upper plate 2?. When the handle attach d to the cover is depressed to move the arm 23 downward, instead of this member closing a contact directly as in the other form of the invention, it=actuates the rod I23 to pivot the contact structure I I1 and thereby release the stop arm I I6.

When the contact spring I22 is in the dotted position, it is no longer acted upon by the stop arm H6, and the contacts 93' (Fig. 2) are permitted to close. As described hereinafter, the closure of these contacts results in the operation of the motor 46 to rotate the cylinder ll and to drive the scanning apparatus. As soon a the stop arm H6 is freed from the restraint of the contact spring I22, the resiliency of the wire I09 is such that the shaft H3 is rapidly rotated within the shaft 39' until the wire takes the form shown in the drawing, in which position the sheet is held in contact with the inside of the transparent cylinder 4|. Upon completion of the scanning operation, the handle rod 23 is released, thereby allowing the contact structure II'I to be moved to the position shown. The stop arm H6 is then intercepted by the contact spring I22 and thereby stops the shaft H3; but since the shaft 33' is still rotating while the upper end of the wire #39 is held stationary, the lower end continues to revolve about the shaft H3. The wire I59, therefore, is wound upon the cylinder shaft and consequently is withdrawn from its sheet holding position. The friction between the circular member H5 and the collar H4 is sufiicient to permit this operation to be performed. Also, the spring I22 is of sufiicient stifiness to maintain the contacts 93 closed. However, as soon as the wire I 09 is tightly wound upon the cylinder shaft, there is in effect a nonyielding driving connection between the shaft 39 and the shaft H3, and the latter is rotated sufiiciently to open the contacts 93. Further movement of the stop arm H6 is prevented by the engagement of the contact spring I22 with a back stop I25. results in the disconnection of power from the motor 46, but since there is aslight overrunning thereof, the shaft H3 does not stop immediately. However, because of the yielding frictional connection between the collar H4 and the circular member H5, the stop arm H8 is not moved any furtheh.

Each subject matter bearing sheet 25 carries a mark such as I26 located definitely with respect to the frame of the subject matter carried by the sheet. this mark appears over the upper right hand corner of the subject matter frame. In accordance with principles which are well known in the art, the scanning at the transmitting station of the spot I28 generates a synchronizing signal which is utilized at the receiving station to initiate scanning by the recording apparatus. This insures that the recording of the subject matter will be within a predetermined frame.

Having reference now to Fig. 4, the operation of the apparatus will be described in connection with typical control circuits therefor. The apparatus may be connected to a circuit which is individual thereto or it may be connected to a circuit which is also utilized by other similar apparatus on a party line basis. Lines LI and L2 are connected to the apparatus of transmitting stations A and B and also to a receiving station C. At the transmitting station B, the photoelectric tube 5'! is connected through an amplifier I29 and direct current blocking condensers i3I to line conductors LI and L2. The windings of two three-position polar relays I32 and I33 are connected respectively to line conductors LI and L2. The windings of relays I 32 and I33 are connected in shunt respectively with filter condensers I 34 and I35, the purpose of which is to divert the alternating current facsimile signals from the relay windings which are responsive to direct current signaling potentials. Similar apparatus at station A is connectedin a like manner to the line conductors.

At the receiving station C the line conductors LI and L2 are connected permanently to the sleeve and tip respectively of a line jack I36. Also, the line conductor LI is permanently connected through a direct current blocking condenser I3'I to one input terminal of a line amplifier I38. Line conductor L2 is connected through a normal jack contact I39 and a direct current blocking condenser I II to the other input terminal of the line amplifier. The output terminals of the line amplifier are connected to control a signaling relay M2. When a plug is inserted in the jack I38, the line conductor L2 is disconnected at the normal jack contact I39 from the line amplifier I33. At the same time line conductors LI and L2 are connected by offnormal jack contacts I43 and I44, respectively, to the arms I45 and I46, respectively, of a manually operable rotary switch I41. The contacts associated with these switch arms are connected The opening of the contacts In the form chosen for illustrationin a predetermined manner to positive and negative grounded batteries I48 and I49, respectively. This portion of the receiving station apparatus is substantially similar to that disclosed in detail in Patent No. 2,262,715, granted to Raleigh J. wise et al. on November 11, 1941, to which reference may be had for a complete disclosure of the apparatus illustrated diagrammatically herein.

A recorder I50, which may be of the type disclosed in Patent No. 2,255,868, granted to Raleigh J. Wise et al. on September 16, 1941, is connected to a plug II, by means of which and the jack I36 the recorder may be connected to the line conductors LI and L2.

In describing the operation of the apparatus, it is assumed that the circuit is idle, the transmitting apparatus of station B is not in operation, the jack I35 at the receiving station C is in its normal condition, and the rotary switch I4! is in the position illustrated. The operator at station B, desiring to transmit a message, moves the cover 2I to provide access to the interior of the hollow transparent cylinder SI and inserts the subject matter bearing sheet 25 in the cylinder in the manner described. The cover is then moved to close the cylinder opening, and the handle 22 is depressed to cause the rods 23 and I23 effect the closure of the contacts indicated generally at 93 in Fig. 4 and specifically at 93 in Fig. 2. Relay I52 is thus operated by means of a circuit which may be traced from the A terminal of a source of alternating current potential I53 over conductor I54, the winding of the relay, contacts 93 and conductors I55 and I56 to the B terminal of the alternating current source. The closure of the inner right hand make contact of relay I52 completes a circuit from the A terminal of the alternating current source I53 over conductors I54, I51 and I58 to the light chopper motor I59, the scanning lamp 52 and the driving motor 46. The other terminals of these devices are connected by conductors I6I, I62 and I56 to the B terminal of the alternating current source I53. Thus, the cylinder M is rotated, causing the arms I85 to press the sheet 25 against the inside of the cylinder wall, and the signal generating apparatus is put into operation, whereby an alternating current carrier signal is transmitted to the line conductors LI and L2.

These alternating current signals are received at the receiving station C by the line amplifier I38 and effect'the operation of relay I42. The closure of the inner make contact of this relay lights a lamp I63 by an obvious circuit from the positive battery I48. The closure of the outer make contact of this relay connects the positive battery I48 to the line conductor LI.

At station B the armature of relay I32, in response to the positive potential connected to line conductor LI, is moved to its marking contact M. A circuit is thus completed from the A terminal of the alternating current source I53 over conductors I64 and I65, the left hand make contact of relay I52, conductor I56, the winding of the electromagnet 95 and conductors I55 and I55 to the B terminal of the alternating current source. The energization of electromagnet 95 moves the forked member 94 into position over the collar 92 of the handle rod 23, thereby making it unnecessary to hold the handle down manually any longer. Also, the closure of the marking contact of the line relay I32 completes a circuit from the A terminal of the alternating current source over conductor I61, the winding of 8 relay I68, the inner break contact of relay I69 and conductors HI and I56 to the B terminal of the alternating current source. When relay I68 operates, a locking circuit therefor is completed from the A terminal of the alternating current source over conductors I64 and I12, the make contact of relay I68, conductor I13, the left hand make contact of relay I52, conductor I61, the winding of relay I68, the inner break contact of relay I69, and conductors [TI and I56 to the B terminal of the alternating current source. The closure of the make contact of relay I58 also connects the A terminal of the alternating current source to one terminal of the electromagnet 95. It is seen that, by reason of this locking arrangement, relay I68 is maintained operated and electromagnet is maintained energized independently of the contacts of the line relay I32. Also, as long as the electromag net 95 is energized with the rod 23 in its depressed position, the contacts 93 are closed to maintain the operation of relay I52.

The lighting of the lamp I63 following the receipt of the alternating current signal indicates to an attendant at the receiving station C that one of the transmitting stations connected to line conductors LI and L2 desires a connection to a recorder. The plug I5I is inserted in the jack I36 to connect the recorder I58 to the line conductors. At the same time the line conductor L2 is disconnected from the line amplifier to release relay I42 and thereby extinguish the lamp I63 and remove the connection of the positive battery !48 from line conductor LI by way of the contacts of relay I42. With the rotary switch I41 in the position shown, however, the positive battery is connected by contact I74 and switch arm I45 to line conductor LI by way of the off-normal jack contact I43.

The apparatus is now in condition to reproduce the message which station B desires to send. The operator at the receiving station C moves the rotary switch I41 so that the arms I45 and 146 are connected respectively to contacts I15 and I16. Positive potential is maintained connected to line conductor LI, and also a similar potential is applied to line conductor L2 by the engagement of which arm I46 with contact I76 by way of the off-normal jack contact I48.

In response to the positive potential on line conductor L2 the armature of line relay I33 is moved into engagement with its marking contact M. A circuit is completed and may be traced from the A terminal of the alternating current source I53 over conductor I54, the inner make contact of relay I52, conductors I5? and I'll, the marking contact of relay I33, conductor I78, the winding of the half-nut magnet I3 and conductors I6 I I62 and I56 to the B terminal of the alternating current source. The half-nut 86 is thus moved into engagement with the feed screw 6'! to initiate the downward vertical scanning movement of the carriage 47. The closure of the marking contact M of line relay I33 also completes a circuit over conductor I'I9, the message being transmitted lamp I9. conductors I8I, I82, I83, I62 and 56 to the B terminal of the alternating current source. The operator at the transmitting station B is thus given an indication that the message is being transmitted to the receiving station C.

The scanning by the transmitting apparatus of the mark I26 generates a synchronizing signal which, when received by the recording apparatus at station C, initiates scanning by the recorder in a well known manner. Every mark appearing on the sheet 25 in register with the frame of the subject matter which is scanned subsequently is recorded at the receiving station.

At the completion of the transmission of the message, the operator at the receiving station C moves the rotary switch arms !45 and I46 into engagement with contacts I84 and I65, respectively. The positive potential of battery I48 is maintained connected to line conductor LI, and all direct current potentials are disconnected from the line conductor L2.

The disconnection of positive potential from line conductor L2 moves the armature of line relay I33 at the transmitting station B to its mid-position, thereby deenergizing the half-nut magnet I3 to permit the carriage '41 to be restored to its upper position and to extinguish the message being transmitted lamp I9.

The attendant at the receiving station C, after inspecting the received copy and finding it unsatisfactory, may make another recording with a different power adjustment by moving the switch arms I45 and I46 again into engagement with contacts I and H6, respectively. However, if the received copy is satisfactory, the switch arms "I45 and I46 are moved into engagement with contacts I86 and I81, respectively. No potential is connected to line conductor L2, and the positive potential of the battery I48 is disconnected from line conductor LI and the negative potential of battery I49 is connected thereto.

At the transmitting station E the armature of line relay I32 is moved into engagement with its spacing contact S in response to the negative potential connected to line conductor LI. is completed from the A terminal of the alternating current source I53 over conductor I 64, the spacing contact of relay I32, the winding of relay I69, the outer right hand make contact of relay I52 and conductors Ill and I56 to the B terminal of the alternating current source. Relay I69 is operated and completes a circuit from the A terminal of the alternating current source over conductor I54, the inner right hand make contact of relay I52, the outer make contact of relay I69, the winding of relay I88 and conductors I83, I62 and I56 to the B terminal of the alternating current source. The operation of re lay I69 also connects the A terminal of the alternating current source over conductor I89 to one terminal of the message received lamp 26, the other terminal of which is connected by conductors I82, I83, !62 and IE6 to the B terminal of the alternating current source. As soon as relay I88 is operated, it is locked through its make contact, contacts 99 and conductors I12 and I64 to the A terminal of the alternating currentv source so that it is maintained operated independently of the contacts of relay I69. Also, the make contact of relay I88 closes a similar circuit to the lamp 20.

The operation of relay I 63 also opens at its inner break contact the locking circiut for relay I68 which releases to open its make contact and to thereby deenergize the electromagnet 95. The latter apparatus is somewhat more sluggish in operating and releasing than any of the other relays and, consequently, introduces a time lag into the release of the transmitting station apparatus. As soon as the forked member 94 is permitted to release the handle rod 23, the contacts 93 are opened to release relay I52. The release of this relay opens, at its right hand make contact, the operating circuit for relay I69 and thereby effects the release of the latter relay. Also the release of relay I52 deenergizes the fac- A circuit l0 simile transmitting apparatus by the opening of its right hand make contact.

The apparatus at the transmitting Station B is restored to normal, with the exception of relay I88 and the message received lamp 29. Upon noting the illumination of the lamp 28, the operator at this station may open the cover 2I to withdraw the message bearing sheet and, if

' desired, replace it with a similar sheet for subseetI quent transmission. Upon opening the cover 2|, the contacts 99 controlled by the cam surface 96 are opened to release relay I88 and to extinguish the lamp 29. The apparatus is then completely restored to its normal idle condition.

When apparatus in accordance with the instant invention is connected to a circuit along with other similar apparatus for operation on a party line basis, facilities are provided for preventing all stations except the one in operation from conditioning their transmitting apparatus for operation and also for providing such stations with an indication that the circuit is being used by another station. A description of these facilities Will be given on the assumption that the transmitting apparatus I9I at station A is using the line conductors LI and L2 for communicating with the receiving station C. As soon as positive potential is applied to line conductor LI by the operation of relay I42 at the receiving station C in response to the reception of a carrier current from the apparatus at station A, line relay I32 at station B and corresponding relays at all other transmitting stations which may be connected to the circuit are actuated to move their armatures to the marking contacts M. A circuit is thus established from the A terminal of the alternating current source I53 over conductor I64, the marking contact of relay I32, conductor I51, the winding of relay I68, the inner break contact of relay I69 and conductors I 'II and I56 to the B terminal of the alternating current source. Relay I68 is operated to close its marking, contact and connect the A terminal of the alternating current source over conductor I66 to energize the electromagnet 95. Forked member 94 is thus moved into a position to intercept the collar 92 of the handle rod 23 in case the handle 22 is depressed in an attempt to start the transmitting apparatus at this station. Contacts 93 are prevented from being closed so that, as long as this condition exists, it is not possible to operate relay I52, which operation is necessary to start the transmitting apparatus. Also, the

closure of the make contact of relay I58 connects the A terminalof the alternating current source I53 over conductor I13 and the left hand break contact of relay I52 to one terminal of the busy line lamp I8. Since the other terminal of this lamp is connected by conductors I8I, I82, I83, I62 and I56 to the B terminal of the alternating current source, the lamp is lighted to give the operator at station B an indication that the line circuit is in use at another point,

This lock-cut condition exists for the duration of the operative engagement of the circuit by the transmitting apparatus I9I of station A by mean of the connection of the switch arm I45 at station C with its contacts I74, I15 and I84. Just prior to the release of the circuit, this switch arm is moved into engagement with its contact I86 to connect negative direct current potential to the line conductor LI, thereby opening the marking contact of relay I32 to deenergize relay I68 and the electromagnet 95. The apparatus at station 13 is thus no longer prevented from being operated, and the "busy line lamp I 8 is extinguished as an indication to the operator at that station that the circuit is now available for use by him, if desired.

As hereinbefore stated, the operation of the handle rod 23 effects the closure of contacts ,93' to start the apparatus and the helical spring member I09 is actuated to its sheet securing position immediately upon the depression of the handle rod 23 before the motor 46 can, come up to speed. Similarly, at the end of a scanning operation the sheet securing helical spring is withdrawn from its contact with the sheet before the driving motor for the cylinder is disconnected from its source of power.

The nature of the invention may be ascertained from the foregoing description of the illustrative embodiment thereof, it being understood that changes in the invention herein disclosed may be made within the scope of the appended claims without departing from the spirit of the invention.

We claim as our invention:

1. In facsimile apparatus, a rotatable hollow transparent cylinder to support interiorly thereof a sheet for scanning purposes, a helically formed spring disposed within said cylinder substantially coaxially therewith, said spring being biased to expand normal to the axis of said cylinder whereby to press a sheet against the inside of said cylinder wall, and means controlled by the rotation of said cylinder to contract said spring whereby to release said sheet.

2. In facsimile apparatus, a rotatable hollow transparent cylinder to support interiorly thereof a sheet for scanning purposes, a helically formed spring having a fixed length disposed within said cylinder substantially coaxially therewith, said spring being biased to unwind partially whereby to press a sheet against the inside of said cylinder wall, and means controlled by the rotation of said cylinder to wind up said' spring whereby to release said sheet.

3. In facsimile apparatus, a rotatable hollow cylinder to support interiorly thereof a sheet for scanning purposes, a shaft disposed coaxially within said cylinder, said shaft and said cylinder being arranged for relative rotation, a resilient helical member having one end fixed relative to said cylinder and the other end fixed relative to said shaft, said helical member being biased to assume a partially unwound condition during equal rotation of said shaft and said cylinder whereby to press a sheet against the inside of said cylinder wall, and means for effecting a relative rotation between said shaft and said cylinder to wind up said helical member whereby to release said sheet.

4. In facsimile apparatus, a rotatable hollow transparent cylinder to support interiorly thereof a sheet for scanning purposes, a hollow shaft disposed coaxially with said cylinder and connected to rotate the same, a second shaft disposed for relative rotation within said hollow shaft and extending substantially the length of said cylinder, a helically formed spring having one end fixed relative to said hollow shaft and the other end fixed relative to said second shaft, said spring being biased to unwind partially whereby to press a sheet against the inside of said cylinder wall, and means for stopping said second shaft during rotation of said hollow shaft to wind up said spring whereby to release said sheet.

5. The invention defined in claim 4, further characterized by means associated with said second shaft stopping means and responsive to the wound up condition of said spring to control the stopping of said hollow shaft.

6. The invention defined in claim 4, further characterized by means including a contact as sociated with said second shaft stopping means and responsive to the wound up condition of said spring to control the stopping of said hollow shaft, and means operable prior to a scanning operation to release said shaft stopping means whereby to allow said spring to unwind and whereby to actuate said contact to initiate rotation of said hollow shaft.

7. In a facsimile machine, a hollow cylinder having the curved portion thereof pervious to light, said cylinder serving to support interiorly thereof a sheet, expansible means mounted within said cylinder and normally disposed out of contact with the inner surface thereof when said cylinder is at rest to permit the insertion of a sheet in said cylinder, means for rotating said cylinder for scanning purposes, and a member engaging said expansible means and movable relative to said cylinder for effecting movement of said expansible means toward said cylinder to press said sheet against the inside of the curved portion of said cylinder.

RALEIGH J. WISE. ROBERT D. PARROTT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 666,154 Reed Jan. 15, 1901 1,409,304 Loomis Mar. 14, 1922 1,545,897 Haynes July 14, 1925 1,546,992 Oppman July 21, 1925 2,182,115 Carlson Dec. 5, 1939 2,201,473 Carlson May 21, 1940 2,356,999 Hogan Aug. 29, 1944 2,469,423 Wise et al. May 10, 1949