US2213476A

US2213476A - Telegraph transmitter

Info

Publication number: US2213476A
Application number: US231617A
Authority: US
Inventors: Albert H Reiber
Original assignee: Teletype Corp
Current assignee: AT&T Teletype Corp
Priority date: 1938-07-18
Filing date: 1938-09-26
Publication date: 1940-09-03
Anticipated expiration: 1957-09-03
Also published as: US2262012A; US2213475A; DE921756C; GB531337A; FR857922A

Description

P 1940- A. H. REIBER 2,213,476

TELEGRAPH TRANSMITTER Filed Sept. 26, 1938 4 Sheets-Sheet 2 g 111 o IQ as |a4- as as 83 INVENTOR.

AL-BERT H. REIBER A ORNEY.

Sept. 3, 1940,

A. H. REIBER TELEGRAPH mmgsmnrmn Filed Sept. 26. 1938 4 Sheets-Sheet 3 FIG. 4

! INVENTOR. FIG. 5 ALBERT H. REIBER M S i A ATTO EY.

, P 1940- A. H. REIBER 2,213,476

TELEGRAPH TRANSMITTER Filed Sept. 26, 1938 4 Sheets-Sheet 4 INVENTOR. ALBERT H. REIBER TTORNEY.

Patented Sept. 3, 1940 UNITED STATES TELEGRAPH TRANSMITTER v Albert E. Reiber, Evanston, 111., assignor to Teletype Corporation, Chicago, 111., a corporation of Delaware Application September 26, 1938, Serial No. 231,617

26 Claims. (Cl. 178-17) This invention relates to printing telegraph.

apparatus and more particularly to telegraph transmitters for the transmission of character identifying signals.

Transmission of character identifying signals in telegraph systems is frequently achieved in accordance with a control strip including control indicia formed in varying combinations elther by manually or remotely operated apparatus. Specifically, the control indicia may be in the form of transverse rows of perforations formed in' a tape either by a keyboard perforator or by a signal controlled perforator which is commonly referred to as a reperforator. The tape thus prepared passes through a transmitter or sensing mechanism to control correspondingly the transmission in succession of impulses identified with the perforations, which has its tape entrance channel separated from the tape exit channel of the perforator under such conditions a short length of tape extends between the perforator and the transmitter and contains a group of perforations, for the last character perforated is not sensed unless the tape is advanced to present such group of perforations to the transmitter or unless the sensing mechanism is made movable along the control strip to sense the last control indicia and efiect transmission of its corresponding signal impulses, as disclosed in the copending application of R. A. Lake, Serial No. 219,770, filed July 18, 1938. In the case of the former instrumentalities, prior to the transmission of signals for the succeeding groups of perforations, blank tape represented by the dis-" An object of the present invention is the control of the position of the movable sensing mechanism by the cyclic operation of the applicator of the control indicia.

Another object of the invention is apparatus wherein a loop of the strip is formed immediately upon operation of the indicia applicator which increases for each succeeeding operation of the applicator when operated at a speed higher than the speed of operation of the signal transmitter.

A still further object of the invention is the provision of a signal storage transmitter wherein the movement of the signal storage strip relative to a control indicia sensing mechanism and the movement of the control indicia sensing mechanism relative to the strip are indeterminate of the number of code combinations stored in the storage strip.

Another object of the invention is the provision of a transmitter wherein the signals are stored on a flexible storage medium and wherein relative movement of a signal sensing mechanism and the medium is determined by the existing characteristics of the strip which are variable.

The above and other objects of the invention are achieved by the provision either of a manually operated keyboard perforator or a signal controlled perforator operative in conjunction with a tape sensing mechanism including a plurality of sensing fingers set permutably in accordance with the perforations or control indicia in the previously prepared control strip to control the transmission of impulses symbolic of the character to be reproduced. The perforator to which the invention has been specifically applied comprises a plurality of key levers arranged to set permutably a plurality of bars which set correspondingly a plurality of interponents to control, upon the actuation of a mechanically operated punch'hammer, the operation of punches arranged in a transverse row to perforate a control strip in accordance with the code allocated to a depressed key lever. Cooperating with the code punches is a feed hole punch for inserting in the tape a feed hole for each operation of the punch hammer which cooperates with a tape feeding mechanism of the sensing unit to effect relative movement between the tape and the sensing mechanism.

The tape sensing mechanism includes the sensing fingers which are mounted in a carrier capable of oscillation about a fixed pivot away from and toward the exit channel of the keyboard-perforator. According to one embodiment of the invention, the movement, of the carrier away from the exit tape channel of the keyboard perforator is determined by mechanism responsive to the cyclic operation of the keyboard perforator. Specifically, such movement is accomplished by the provision of a pawl and ratchet mechanism op rated upon each operation of the punch hammer of the perforator to position an arm and determine the extent of movement of the carrier in which the sensing fingers are mounted. For each operation of the'punch hammer the ratchet mechanism is operated to move the arm and allow the rotation of the carrier about its pivot an amount less than the separation between succeeding transverse rows of code perincreases in length for each succeeding movement of the carrier.

Disablement or the feeding pawl and the return to normal of the ratchet wheel of the ratchet mechanism is accomplished by a lever operated when the arm which determines the position of the carrier is in contact with the carrier upon the next succeeding operation of the punch hammer of the perforator. The extent of movement of the arm is determined by the number of teeth on the ratchet wheel, for when a predetermined position is reached, further advancement of the arm is avoided by the omission of teeth on the ratchet wheel.

As the carrier with the sensing fingers moves about its pivot in a counterclockwise direction, the loop of tape may increase. However, for each operation of the tape feeding mechanism of the sensing unit, relative movement between the carrier and the tape will be effected, and the signal perforations will be sensed and corresponding signal impulses will be transmitted.

When the arm has been moved to its fullest extent and a loop of tape between the carrier and the perforator has been formed, the tape feeding mechanism of the sensing unit, which is in accordance with the disclosure of the foregoing application, operates to feed the tape through the sensing unit to permit the sensing fingers to 9 sense successively the transverse rows of perforations. When the tape between the sensing unit and the perforator becomes taut or when the loop of tape therebetween has been exhausted, the carrier with the sensing fingers will be moved along the tape to bring the carrier in abutting relation to the perforator. Such operation, however, assumes idle condition of the perforator and under such circumstances the arm which determines the rotative position of the carrier remains in its extreme rotative position. However, if during the period the carrier is'moving along the tape or toward the perforator the perforator is reoperated, the feed and holding portions of the ratchet mechanism will be removed from the teeth of the ratchet wheel and the wheel will be restored to normal to allow the arm to engage the carrier of the sensing fingers. Of course, if the carrier abuts the perforator prior to the reoperation of the perforator, the arm remains in its extended operative position until the perforator is again operated, when it will be restored in engagement with the carrier due to the restoration of the ratchet wheel to its normal or starting position.

Transmission of signals corresponding to the setting of the sensing fingers in accordance with the perforations in the tape is efi'ected through the control of appropriate levers which control, in response to the rotation of a transmitting cam drum, the cyclic operation of a series of electrical contacts through which the impulses identified with the code perforations are transmitted. Rotation of the transmitting cam drum is controlled by an electromagnet energized or de- 55 energized according to the rotative condition of the carrier of the sensing fingers upon its pivot. When the carrier of the sensing fingers abuts the perforator, the electromagnet is de-energized and the transmitting cam drum is stopped.

According to another embodiment of the invention, the movement of the carrier of the sensing fingers about its pivot away from the tape exit channel of the perforator is determined by a spring or other elastic medium intermediate 75 the carrier and the perforator. As the tape is advanced from the perforator through the operation of the tape feed mechanism thereof, the carrier of the sensing fingers will rotate about its pivot away from the perforator. The extent of rotation of the carrier away from the tape exit channel of the perforator is determined by the characteristics of the spring or elastic medium secured to the carrier and the character of the perforated tape intermediate the sensing fingers of the carrier and the perforator. For example, if the section of tape intermediate the sensing fingers and the perforator has been weakened by a large number of perforations, the carrier will be moved away from the tape exit channel of the perforator an extent materially less than the extent it will be moved if such section of'tape does not carry a large number of perforations which, of course, is determined by the code combinations of perforations appearing in the noted section of the tape, as determined by the operation of the perforator. Under such circumstances the advancement of the tape relative to the sensing fingers is not efiected when the number of transverse rows of perforations exceeds a predetermined number. Likewise, the movement of the carrier and the sensing fingers relative to the tape is not effected when the number of transverse rows of code perforations in the tape is below the number to which the tape is moved relatively to the sensing fingers. In other words, relative movement between the tape and the sensing fingers is not predetermined by the number of transverse rows of code combinations of perforations included in the section of tape intermediate the sensing unit and the perforator.

A more complete understanding of the invention may be had from the following description, taken in conjunction with the accompanying drawings, wherein Fig. 1 is a partial plan view of the essential elements of a keyboard perforator, tape sensing unit and a signal transmitting device in accordance with one embodiment of the present invention;

Fig. 2 is a front elevational view of the structure disclosed in Fig. 1;

Fig. 3 is a view of a part of the structure disclosed in Fig. 2 but showing the sensing unit displaced from the perforator;

Fig. 4 is an end elevational view of the structure disclosed in Fig. 1;

Fig. 5 is a sectional view taken substantially along the line H of Fig. 1;

Fig. 6 is an exploded perspective view of the tape sensing unit and the transmitter shown in Fig. 1;

Fig. 'l is a detailed view of the mechanism utilized for effecting relative movement between the sensing unit and the perforated tape;

Fig. 8 shows another embodiment of the invention;

Fig. 9 illustrates a condition of operation of the structure shown in Fig. 8;

Fig. 10 shows a different condition of operation of the structure disclosed in Fig. 8 when the section of tape between the perforator and the sensing unit includes a small number of perforations; and i Fig. 11 is a circuit diagram of the electrical connections for the apparatus disclosed in Fig. 1.

The perforator The present invention may be considered as including three principal units, a tape perforator 9, a tape sensing unit Ill, and a transmitting unit N (Fig. 1). Each of the several unitsis mounted on a base casting |2.

The perforator shown in Figs. 2 and 5 comprises a set of punches |3 movable through openings in upper and lower guide plates l4 and I5 and cooperating with a die plate IS, the plates l4 and I6 being spaced apart to form a tape guide. The punches l3 are selectively operated by an actuating member or hammer H and a set of permutation bars or interponents l8 corresponding in number to the number of punches I3.

The hammer I1 is arranged to oscillate about a pivot l9 and is operated by an arm 29 secured to one end of a lever 2| which is pivoted on rod 25 (Fig. 4) journaled in ears or

projections

28 and 29 formed on the outer edge of a vertical wall 30 of a casting. Lever 2| (Figs. 1 and 4) carries at its opposite end a cam roller 32 which cooperates with a cam to operate cyclically hammer I1 and effect its oscillation and correspondingly the operation of the punch pins l3.

As disclosed in Fig. 5, a sleeve 33 having a pin 34 is adjustably mounted on arm 20. Pin 34 extends loosely through an aperture in hammer |1.

Mounted oppositely to arm 29 is a second arm 38 which, like arm 20, carries an adjustable sleeve 31 which has an elongated pin 38 in alignment with a'punch pin 39. Punch pin 39 is partially enclosed in a housing 40 which conceals a spring 4| arranged to subject punch 39 to spring tension and restore it to its normal position. Punch 39 is guided at its upper and lower extremities by guide plates and cooperates with a die plate 42 which is separated from the upper guide plate to form a tape guide. Punch 39 serves to apply to tape 43 the feed holes in advance of the application of the code perforations by code punches l3. It is thus seen that for each operation of lever 2|, the hammer |1 will be oscillated about its pivot l9 and the feed hole punch 39 will be moved upwardly by pin 38 which extends through an aperture in hammer 39 to perforate the feed hole, and will be restored to the position shown in Fig. 2 by spring 4 I, following the restoration of arm 20 of lever 2| to the position shown in Fig. 2.

The interponents or permutation elements |8 are movable back and forth over the face of hammer l1 and are adapted to be positioned in different combinations with their outer ends either-in operative positions beneath the corresponding punches l3 or in inoperative positions out of alignment with punches I3.

The free end of hammer I1 is upturned, which portion is slotted to form guide channels for the forward end of each of the interponents |8. Upon each setting of the interponents l8, the lever 2| is oscillated and hammer I1 is moved about its pivot to form a row of perforations in tape 43 through the actuation of punches |3 corresponding to the setting of the interponents l8. Also, upon the operation of arm 2|, pin 38 will be actuated and feed hole punch 39 will be operated to perforate the feed hole in tape 43 in advance of the formation of the row of code perforations. v

Withdrawal of the feed hole punch is achieved by spring 4|, whereas the withdrawal 'of the'code punches is accomplished by a stripper bail .44 which is pivoted at 45 and which has secured thereto one end of a retractile spring 48. 'As disclosed, the punch pins l3 are each provided with a shoulder which cooperates with the lower surface of spring actuated stripper bail 44, so that when the punches |3 are raised, stripper bail 44 will be, moved about its pivot 45 against the action of spring 48- and without any binding action on the punches l3. When hammer H is returned to the position shown in Fig. 2, spring 46 is effective to withdraw the actuated punches l3 and restore them to their normal unactuated position. 1

As previously described, for each operation of lever 2|, punch 89 is operated to form a feed hole adapted to be engaged by the pin teeth on a feed drum 41. The latter is provided with ratchet teeth 48 to be engaged by a feed pawl 49 which is pivotally mounted on hammer l1 and which is thus reciprocated upon each operation of the latter. A star wheel 50, Fig. 8, and a knurled portion 5|, Fig. 5, which facilitates manual rotation, are integrally formed and are secured to feed drum 41 by means of a nut. Formed on the out side of abearing sleeve through which drum 41 passes is a disc 52 provided with a projection 53 arranged to cooperate with an arm 54 formed on feed pawl 49 and arranged with an arm 55 cooperating with a slot formed in a member 56 which is capable of being depressed to cause the withdrawal of feed pawl 49 from cooperation with teeth 48 and to back step the feed drum 41 to present a previously perforated row of perforations in alignment with the code punches I3. A spring tensioned lever 51 pivoted on member 56 cooperates with star'wheel 59 to back space the feed drum 41 and, in turn, the tape 43.

A spring 6| connected to the lower extremity of feed pawl 49 serves to hold the feed pawl in engagement with ratchet teeth 48 of the feed drum 41 and also normally holds hammer |1 against the adjustable sleeve 33. When hammer I1 is moved in a clockwise direction by the action of lever 2|, spring 6| is extended. Consequently, when the force on lever 2| is relieved, the energy stored in spring 6| is released and hammer I1 is restored to the position shown in Fig. 2. Feed pawl 49 will also be restored and, in being so moved, will rotate feed drum 41 to advance the tape 43 to present a succeedingarea thereof in alignment with the code punches l3. It is thus seen that for each operation of hammer |1, feed drum 41 will be rotated and the tape 43 will be advanced step by step.

The interponents or permutation elements l8 are set in different combinations by a plurality of key levers 62 suitably mounted on a pivot rod and normally held in raised position by individual springs, the levers being provided at their forward ends with key tops 63.

Beneath the key levers extend a number of pairs of code bars, and since in the form shown arm 66. Each bar has its ends guided by oppositely disposed guide combs 61. These rock arms are pivotally mounted on a shaft 68 secured to a block 69 which extends transversely of the bars 64 and 65 'and which is arranged with a plurality of slots, one for each rock arm 66. A similar block (not shown) is positioned adjacent the right-hand end of

bars

64 and 65, as viewed in Fig. 2, which also carries ashaft 68 constituting a pivot for correspondingly shaped rock arms and which also serves to limit the endwise movement of

bars

64 and 65. One pair of rock arms is interposed between each two code bars comprising a pair and the bars are held in proper spaced relation by guide combs, one of which is shown at 61. The rock arms 56 are substantially T-shaped or widened at their upper ends and are provided with offset lugs on opposite sides of and spaced some distance from the shaft 58. One of the lugs of each arm projects forwardly into a notch on the lower edge of the corresponding code bar 84, and its other lug projects rearwardly beneath the lower edge of the corresponding code bar 65. With this arrangement, the depression of either bar of a pair of code bars rocks the arms and lifts the other code bar.

Each pair of rock arms 66 is pivoted to a longitudinally movable permutation bar 18. In the form disclosed, each bar 18 is connected to its individual lever II pivotally mounted on shaft 12 and having its upper end connected to its interponent I8; that is, individual to each bar 18 and itscompanion interponent I8 is a lever II, so that for each movement of bar 18, corresponding movement of 'interponent I 8 results.

Cooperating with the upper ends of levers II, which are beveled, is a rod or roller 13 secured to a U-shaped member 14 pivoted on rod 15 and urged into cooperation with the beveled end of each of the levers II by a spring 16. Rod I8 serves as a detent for levers II.

Each of the key levers 52 which extends across the code bars 6485 is arranged, when operated, to engage and depress one of the code bars of each pair and thereby set the same and the permutation bars 18 and interponents I8 in acharacteristic combination. correspondingly, the punches I3 will be operated in the same characteristic combination upon the operation of hammer I'I through lever 2I.

For effecting the operation of the punches I8 through the interponents I8, each key lever 62 is arranged to depress a universal bar 11 which is slidably mounted in the same manner as the code bars 84-65 and also cooperates with a pair of rock arms secured to a connecting link 18 to operate under the tension of a spring I9 a bail 88 which constitutes a part of the release mechanism effective for controlling the application of power to lever 2|. As disclosed in Fig. 5, an arm 8| having one end fastened to an arm of bail 88 engages an adjusting screw 82 fixed in one end of pivoted arm 83 to rotate, when the connecting link 18 is shifted, arm 83 and remove the stop projection from the path of spring operated latch 84 and allow application of power to the cam for operating lever 2|. The form of the release mechanism may correspond to that disclosed in Patent No. 2,019,505 to A. H. Reiber of November 5, 1935, and consequently reference is made to such patent for a full and complete understanding of the construction and operation of the release mechanism which is operated by the universal bar," upon the depression of any of the key levers 82.

As disclosed in Fig. 1, an electric motor 88 has on its shaft a gear 89 which meshes with a gear 98 secured to a shaft 9I journaled in

bearings

92 and 98. Also secured to shaft 9| is a gear 98 and the driving portion of a friction and positive clutch 95. Through the friction and positive clutch 95 a sleeve 98 on shaft 9I is rotated. Secured to sleeve 96 is a cam 91 which cooperates with roller 82 mounted on one arm of lever 2|.

Upon the depression of any of the key levers 82, the code bars 6l-85 will be operated as will the universal bar TI to effect the operation of the clutch release mechanism. Upon the operation of such mechanism, clutch 95 is effective, whereupon power is communicated to sleeve 96 and thus to cam 91., As cam 91 rotates, lever 2I is operated to actuate hammer I1 against the action of spring BI. It is thus seen that, for each operation of a key lever, the code bars -65 will be set in a characteristic combination, that the interponents I8 will be correspondingly set,'that the clutch 95 will be effective and power will be applied to cam 91, and that through'cam 91 the hammer I! will be moved in'a clockwise direction, as viewed in Fig. 2, to cause code punches I3 to perforate the tape and punch 39 to perforate the feed hole, following which the hammer i1 is restored to its normal position by the action of spring 6|, which serves also to advance the feed drum 41 through the operation of feed pawl 49 to advance tape 43 to present the succeeding area thereof in aligmnent with punches I8.

Between feed drum 41 and the entrance end of the tape guide formed between the plates I4 and I6 is a member 98 which has its upper surface curved to direct the tape from the feed wheel to the entrance of the tape guide in cooperation with a wire loop 99 formed to correspond with the contour of drum 4'! and arranged to hold the tape firmly against thedrum 41. The wire loop 99 is fastened to an arm I88 which is pivoted to permit the wire loop 99 to be moved free of the feed drum 41. Positioned above the code punches I 3 is a chaff or chad chute I M A similar chad chute is provided for feed hole punch 39.

- The sensing unit The sensing unit includes two substantially L-shaped side members I85 and I86, each of which, as. shown in Fig. 6, has a horizontally projecting portion I81, a downwardly extending leg I88, and a horizontal portion I89, which are spaced by a metallic spacer and which are joined by welding or riveting.

The sensing unit which includes the frames I85 and I88 is pivoted, as shown in Fig. 4, on pivot pins H8 and III in a manner to permit free oscillation of the sensing unit. The pivot pins H8 and III are secured to vertically extending side members H2 and H3 (Figs. 2 and 6 respectively) of a U-shaped member which is fastened to the base casting I2.

The sensing unit, as disclosed in Fig. 2, normally abuts the plates I4 and I8 of the perforator and has its entrance channel for the perforated tape in alignment with the exit channel of the tape guide formed between plates I4 and I6. Extending between and secured to the side frames I85 and I86 is a plate I I5 which carries a pilot post H5 and a hinge block 1. Hinged to block II! is a tape gate I I8 which has an aperture in alignment with pilot post H8 and which cooperates when in a horizontal position with a spring latch II9 which holds it in its operating position. Secured to the gate II9 by a screw is a reed spring I28 which carries at its free end two pins I2I and I22, Fig. 6.

The plate II5 has its upper surface depressed or grooved to form a channel for the tape as it passes through the sensing unit and has adjacent its right-hand edge, as viewed in Fig. 2, a plurality of apertures. Likewise, the right-hand edge of the gate II8 has-a plurality of notches in alignment with the apertures in plate II5 when the gate is latched by latch II9.

The apertures in plate II5 receive the reduced portion of a sensing pin I25; that is, there is a sensing pin I25 individual to each of the code apertures adjacent the right-hand edge of plate H5. Inasmuch as there are five code punches u I3 there will be a corresponding number ofsensing fingers I; for example, there will be a sensing finger or pin I25 for each of .the possible perforations appearing in a transverse row of perforations.

The separation between the code punches I3 and the apertures in plate I I5 when the plate II5 abuts the plates I4 and I6 corresponds to the normal spacing between successive transverse rows of perforations in tape 43. Usually the transverse rows of perforations in tape 43 are one-tenth of an inch apart and therefore the punches I3 and the apertures in plate II5 are correspondingly separated. Intermediate the upper legs of the frame members I05 and I06 and in the space formed by the metallic spacer is a slidably movable member I26 which is formed with a cam groove I21, Fig. '7, and which carries on its upper extremity pins I28, I29, and I30. Pins I28 and I29 are ,of' the same length but pin I30, as shown in Fig. 7, is considerably longer than pins I28 and I29, the purpose of which will appear more clearly hereinafter. Cooperating with the cam groove I21 in member I26 is a pin I3I secured to its upper end, Fig. 4, of a cam operated arm I32. The pin I3I has an enlarged head I33, as shown in Fig. 4, to insure that the pin I3I will not be accidentally displaced from the cam groove I21.

As shown in Fig. 7, the downwardly projecting legs I08 of portion I01 of the side frames I05 and I06 are arranged with straight slots I34 to con- 4 H0 and III.

fine the movement of pin I3I in a vertical plane or in a straight line along or on a radii. To facilitate removal of pin I3I, the lower portion of cam groove I21 and the lower portion of the slots I34 in the legs I08 of portions I01 are enlarged sufliciently to receive the head I33 of the pin I3 I.

As will be described hereinafter, member I26 and arm I32 are operated in timed relation. Arm I32 is drawn downwardly in the slots I34 and when so drawn and due to the particular shape of cam groove I21, member I26 will be moved to the left as viewed in Figs. 1 and 6, and relative movement. between the sensing unit I0 and the tape 43 will be effected. Member I26 then is moved downwardly to withdraw pins I28, I29, and I30 from engagement with the feed perforations in the tape 43. Following this action, arm I32 is moved upwardly and due to the camming action, member I26 is moved to the right as viewed in Figs. 1 and 6. The member I26 is thereafter elevated to cause the pins I28, I29,

and I30 to engage other feed perforations in the tape 43 to achieve, on a subsequent cycle, relative movement between the sensing unit I0 and the perforated tape 43.

Secured'to the side members H2 and I I3 are L-shaped members I38 and I39, respectively. Extending between the L-shaped members I38 and I39 is a pivot shaft I41 on which is mounted a plurality of bell crank levers I48, I49, I50, I5I, and I52, Fig. 6. These bell crank levers are individual to a sensing finger I25. As disclosed, the sensing fingers I25 are pivotally secured to one arm of their respective bell crank lever on a center line substantially coincident with pivots The bell crank levers have an extension I53, Fig. 6, cooperating with a pivotally mounted guide comb I54. .,'Fastened to the other arm of the bell crank leversfis jaretractile spring I55, Fig. '3, which serves tofrotate its bell crank in a counterclockwise direction,--as viewed in Figs.

2 and 3, and to move its sensing finger I25 vertically to sense the perforations in tape 43. If a mentis correspondingly restricted.

Tofacilitate assembly, each of the sensing fingers I25 is provided near its lower extremity with an aperture arranged to be engaged by a pin secured near the end of the horizontally extending arm of each of the bell crank levers I48-I52. A reed spring I56, Fig. 2, riveted to such arm of the bell crank lever, serves to retain the lower end of the sensing finger and prevent its accidental displacement.

Guide comb I54 which is normally under the tension of a spring I51, one end of which is fasttened to a spring post secured to members H2 and I I3 and the other end secured to the righthand horizontal projection of the guide comb I54, has ears I63 and I64, Fig. 6 apertured to receive pivot shaft I41 and arranged to permit the free rotation of comb I54 against the tension of its retractile spring I51. The left-hand ear I64 of guide comb I54, as viewed in Fig. 6, is secured to an arm I58, Fig, 4, of a T-shaped lever I59, Fig. 2. Arm I60 of T-lever I59 cooperates with a cam for moving cyclically comb I54 about pivot shaft I41 for the purpose later to be de scribed. Arm I6I of T-lever I59 cooperates with a pin I62 to limit the movement of comb I54 against the action of spring I51. Also rotatably mounted on pivot shaft I41 is a lever I66 which has one end fastened to member I26 and which has its other end secured to a bell crank lever I61 also pivotally mounted on shaft I41 and having an arm which cooperates with a cyclically operated cam to effect reciprocational movement of member I26. Also pivotally mounted on shaft I41 is an arm I68, Figs. 1 and 6, which is secured to lever I32 and which is fastened through its arm to a lever I69 carrying a cam roller I10 which is held in cooperation with its cam by a spring "I having one end secured to an arm of the lever carrying roller I10 and the other end secured to a spring post on upright I I3. Secured to side frame I05, Figs. 4 and 6, is a pin I14 which cooperates with the insulated end of an electrical contact spring I15 which cooperates with an electrical contact spring I16 to complete the energizing circuit for a control electromagnet I11.

Movement of the frame including the' side members I05 and I06 about the pivots H0 and III is under the control of mechanism operated cyclically with the operation of the perforator; that is, for each operation of the perforator, mechanism is operated to allow a predetermined movement of the frame carrying the sensing fingers I25. Such movement, in accordance with a specific embodiment of the invention, is predetermined; for example, each movement as determined by the teeth on a ratchet wheel is less than the spacing of adjacent transverse rows of perforations .in the tape 43.

The mechanism just referred to consists of a ratchet wheel I8I rotatably mounted on a shaft I82 journaled in the side plates I I2 and I I3. Only a. portion of the periphery of the ratchet wheel I8I carries teeth which are engaged by a feed pawl I83 and a holding pawl I84. By failing to provide teeth on the entire periphery of the ratchet wheel I8I, it will be rotated only to a predetermined point or a point where the feed pawl l83' no longer engages 1 a tooth in the ratchet wheel I6I. Further rotation of the Fig. 6, is thus prevented.

Holding pawl I 84 is pivoted on a pivot shaft I85 independently of the feed pawl I 83 which is pivoted to a horizontally extending member I88 and which is normally under the tension of a spring I81 to engage the teeth of the ratchet wheel I8I. Holding pawl I84 has a projecting portion I88, as viewed in Fig. 2, sufficient to be engaged by the pawl I83 and moved under predetermined conditions of operation against the tension of spring I89 free of the teeth of the ratchet wheel I8I and allow the restoration thereof by a restoration spring I 88 to its normal or starting position or the position shown in Fig. 3.

Member I86 is pivotally mounted to a plate I9I fastened to the side frame of the perforator and has attached to it one end of a spring I92; the other end of which is fastened to a fixed spring post. Member I 86 is slotted at I93, Fig. 2, to receive a screw I94 secured to a shouldered bushing in an aperture of arm I95 which is secured to a U-shaped frame I96, Fig. 6, which is pivotally mounted on a pivot shaft I91. Screw I94 serves to clamp adjustably the shouldered bushing to member I86 at a distance from fixed pivot I98 to allow proper travel of feed pawl I83. Cooperating with the intermediate section of the U- shaped member I91 is a pin I98 secured to the end of arm 28 and serving to control its operation.

Arm- 28, as previously described, is a part of lever 2| which is pivoted on shaft 25 and which is operated cyclically by cam 91 secured to sleeve 96. Upon the operation of lever 2| and the upward movement of arm 28, .as viewed in Fig. 2,

which directional movement occurs incident the perforation of the tapein accordance with the position of the interponents I8, rod I98 will be moved free of the central section of Ushaped member I96 and spring I92 which is normally under tension, will be permitted to rock member I 81 counterclockwise, as viewed in Fig. 2 and thus cause the downward movement of the feed pawl I 83 sufliciently to enable it to engage the next succeeding tooth on the ratchet wheel I8I which, as shown in Fig. 2,- is normally under the tension of a restoration spring I88. When the perforating operation has been completed, the lever 2I is moved downwardly bythe action of spring 6|, whereupon the feeding pawl 49 of the tape feeding mechanism is operated to advance the tape 43 and simultaneously therewith, pin I88 engages the central section of U-shaped member I96 to cause the downward movement of arm I95 and correspondingly the upward movement of pawl I83 against the tension of spring I 92. Pawl I83 having engaged the next succeeding tooth of ratchet wheel I8 I, the latter will be rotated in the direction of the arrow, Fig. 6, against its restoration spring I88. Rotation of ratchet wheel I8I, it is thus seen, is timed with the operation of the feed pawl 49 and the step-by-step advancement of the tape 43 through the corresponding operation of feed drum 41.

For each operation of the punch hammer I1, the feed pawl I83 will be operated to cause the step-by-step advancement of the ratchet wheel I8I which will be held in its advanced position by holding pawl I 84. Such operation will continue until the feed pawl I83 engages the smooth surface on the periphery of ratchet wheel I 8|, in which position the ratchet wheel will be held by the holding pawl I84 until it is moved free of the teeth of ratchet wheel I8I, as will be subsequently described.

2,218,476 ratchet wheel I 8| in the direction of the arrow,

Secured to the face of ratchet wheel I8I is a pin 282. This pin lies'in the path of a cam surface 283 formed on the underside of an arm 284 of a lever 285, which is pivoted on pivot pin H8 and which has a vertically extending arm 281. As ratchet wheel I 8| is advanced step by step, pin 282 engages the under surface 283 of arm 284 and, due to the contour of surface 283, lever 288 will be permitted to rotate about shaft III and thus control the movement of the sensing unit I8 through cooperation of adjustable screw 2I8 with side member I85 of the frame which carries the sensing fingers I25. Adjustable screw 2" is "fastened and locked in its adjusted position to a plate 2I I which is pivoted to the upper end of arm 281 of lever 285 and has secured to it a rod 2I2,.

the lower end of which is fastened to a member 2I3 pivoted on a shaft 2 which is joumaled in ears 2I5 and 2I6 formed in the vertical arm 281 of lever 285. As shown in Fig. 6, side member I85 has a projecting portion 2" which is engaged by one end of the adjustable screw 2I8 and, due to such cooperation and the cooperation of pin 282 with surface 283 of arm 284 of lever 285, the movement of *the sensing unit I8 will be controlled. For example, when the ratchet wheel I8I is rotated, pin 282 will progress correspond ingly in a circular path, and due to its engagement with surface 283 of arm 284 of lever 285, arm 281 will be permitted to rotate in a counterclockwise direction, as viewed in Fig. 6, and the frame including the sensing fingers 285 will be moved correspondingly. In order that the movement imparted to the frame by operation of the punch hammer shall be such as to move the free ends of the sensing pins less than one-tenth of an inch, the spacing of adjacent transverse rows of perforations in tape 83, as previously set forth, the spacing of the teeth on ratchet wheel I8I, the cooperation of pin 282 with surface 283 of arm 284, the movement of pawl I83, and the other variables involved in the related structure bear a definite relation.

Significant is the fact that thetape is advanced from the perforator, due to the cyclic operation of pin drum 41, in timed relation with the operation of the ratchet wheel I8I. Consequently, when the tape is moved out of the perforator, the ratchet wheel I8I will be operated and the sensing unit will be permitted to move in a counterclockwise direction a distance dependent upon the spacing of the teeth on ratchet wheel I8I and the contour of surface 283 of arm 284 of the lever 285. However, when the feed pawl I83 engages a smooth surface of ratchet wheel I8I, further rotation thereof is precluded and it will be held in its advanced position with pin 282 engaging the forward edge of surface 283 of arm 284, and the sensing unit will then be in its extreme counterclockwise position, as viewed in Fig. 3.

Restoration of ratchet wheel I 8| by the action of its spring I88 is controlled by the removal of the feeding pawl I83 and the holding pawl I84 from engagement with the teeth in the ratchet wheel I8I. To accomplish such a result, feeding pawl I83 has an arm 2I8 engageable by a downwardly projecting arm 2I9 of pivoted member 2I3 which, as shown in Fig. 4, is normally under tension of spring 228 having one end fastened to a projection on member 281 and the other end secured to pivoted member 2I3. Spring 228 overcomes the weight of and the gravitational action on member 2I3 and its associated parts.

As was previously described, member 2I3 is pivoted on shaft 2 I4 and is connected by rod 2 I2 to pivoted member 2| I, which carries adjustable screw 2") and further, that adjustable screw 2| 8 engages projection 2". When projection 2I1 engages screw 2I8, member 2 will be rotated in a counterclockwise direction, rod 2| 2 will be moved downwardly, and member 2I3 will be rotated about its shaft 2I4 in a counterclockwise direction, as viewed in Fig. 6 against the action of spring 228. Vertically extending portion 2I9 of member 2I3 will thus be out of the path of extension 2I8 on feeding pawl I83 and, under such circumstances, there will be no change in the operation. However, if projection 2I1 is not in engagement with screw 2I8, member 2I3 will be rotated to a position where extension 2I9 lies in the path of extension 2I8 of feed pawl I83 which, upon the next cyclic operation of the punch hammer, will cause the feed pawl I83 to be moved in a counterclockwise direction, as viewed in Fig. 6, and carry with it, due to projection I88, holding pawl I84 free of the teeth of ratchet wheel I8I. Spring I88, having been extended due to the step-by-step operation of ratchet wheel I8I, will restore the ratchet wheel to its normal position or the position shown in Fig. 6. The lever 285 will, of course, be restored to the position also shown in Fig. 6.

The transmitting unit Individual to each of the bell cranks I48-I52 is a bell crank lever 225, Figs. 3 and 6, pivoted on a shaft 228 and held in proper position by spacing washers on shaft 226 and by a guide comb 221, Fig. 2.

Each bell crank lever 225 has a hook 228 at its upper end which engages the insulated upper end of a spring contact 229 and each of the latter cooperates with acontact spring 238, the pairs of contact springs being mounted upon but insulated from a supporting bar 23I, Fig. 2, carried by the base casting I2. Each spring contact 229 tends to engage its associated contact spring 238 and also serves to hold a lug 232 on the horizontal arm of 'the corresponding bell crank lever 225 in engagement with the surface of a cam drum 233 serving as the signal transmitting cam assembly and forming a part of a cam sleeve 234 on a horizontal shaft 235 and extending over the horizontal arms of the bell crank levers 22 5. The cam drum 233 is provided with a helical series of recesses which, as the cam is rotated, successively pass over the lugs 232 of the bell crank levers 225. As the corresponding recess passes over one of the lugs, the associated

switch contacts

229 and 238 are closed, provided the horizontal arm of the bell crank lever 225 is not restricted in its movement.

The shaft 235 is journaled in

end plates

231 and 238, Fig. 4. On the sleeve 234 carrying cam or cam drum 233 is a shoulder or cam 239, Fig. 1. Sleeve 234 is splined to a driven portion 248 which constitutes a part of a positive clutch 242 through which power is communicated to sleeve 234. The driven portion 248 of the clutch has integrally formed therewith a cam surface 243 which cooperates with an extending portion 244 of a bail or clutch throwout lever 245 pivoted at 246 and functions as a clutch disengaging means. The laterally extending portion 244 of bail 245 cooperates with the armature of electromagnet I11 which, when energized, withdraws the hori-.

zontal projection 244 of bail 245 free of the cam surface 243 and its horizontal projection to allow portion 248 to be shifted by spring 241 into cooperation with the driving portion 248 of the clutch 242, which is secured to shaft 235 on which is mounted a gear 249, the latter being meshed with gear 94 and driven continuously from power supplied by motor 88. Normally, of course, spring 241 tends to move the driven portion 248 into cooperation with the driving portion 248 of .the positive clutch but is prevented from such movement due to the horizontally extending portion 244 of bell crank lever 245 with theprojection 243 on the cam surface. Consequently, the transmitting cam sleeve or drum 234 which carries the cams 233is normally held against rotation by the stop member or bell crank lever 244 which is held in such position upon the deenergization of electromagnet I11.

End plate 231 also supports one end of shaft 226, the other end of which is supported in plate 258 which, like plate 231 is secured to the base casting I2. Also as shown in Fig. 1, a spring. 25I

surrounds shaft 226 and is positioned between plate 231 and the first of the bell crank levers 225 to permit slight lineal movement along shaft 226.

Also secured to cam sleeve 234 are

cams

252, 253, and 254. Cam 252 operates on roller I18 carried by a lever I69 to move arm I68 and, through it, arm or connecting link I32. Cam

253 operates on arm I58 of T-shaped lever I59 to rotate guide comb I54 against the tension of its spring I51 to permit movement of the bell,

crank levers I48-I52 by the action of springs I about pivot shaft I41 in a counterclockwise direction, as viewed in Fig. 2, and to insert the sensing fingers I25 in the perforations in the tape 43. During a subsequent portion of its cycle, cam 253 allows spring I51 to move combv I54 through which bell crank levers I48-I52 are rotated about shaft I41 in a clockwise direction, as viewed in Fig. 2, and thus withdraw the sensing fingers I25 free of tape 43. rotates, it cooperates with arm I61 secured to lever I66 which, in turn, is secured to member I26 which through the action of cam 254, is reciprocated to cause the pins I28, I29, and I38 to disengage and engage successively the feed perforations in tape 43.

As previously described, cooperating with each of the bell crank levers 225 is a bell crank lever I48, I49, 58, I5I, and I52 which are positioned in accordance with the positions assumed by their associated sensing fingers I25. If a sensing finger I25 is held depressed, which will be the position it assumes if a perforation is not aligned therewith, the free end of its bell crank lever lies in the path of the horizontal arm of its bell crank lever, such as 225. Thus, when the recess in cam 233 aligns with lug 232, the bell crank lever such as 225 is held against move* ment and the

contacts

229 and 238 will be held open. However, if a sensing finger I25 is allowed to ascend, which results from the presentation of a perforation in alignment therewith, its associated bell crank lever such as 225 is released upon the presentation of the recess of cam 233 thereto, which results in the closure of

contacts

229 and 238. r

As sleeve 234 rotates, the recesses in cam 233 are presented successively to the lugs 232 on the bell cranklever 225 and the

contacts

229 and 238 will be operated in a manner corresponding to if the sensing fingers I25 sense perforations in the tape 43, the associated bell crank levers 225 will be operated for effecting the sequentialclosure of

contacts

228 and 238. However, if no As cam 254 the position of the sensing fingers I25; that is,

perforation is sensed, then the

contacts

229 and 230 will not be allowed to close but will be held open in the position shown in Fig. 2.

The periphery of shoulder or cam 239 is formed with a recess to be entered by a roller 260, Fig. 1, carried by a spring biased arm 26I suitably pivoted to the frame. The purpose of the cam surface on cam 239 and particularly the recess therein in cooperation with roller 260 is to prevent singing or chattering of the clutch comprising driven portion 240 and driving portion 248 during periods of arrestment of the latter and to control the initial rotation of cam 233. Since spring 241 opposes the disengagement of driven clutch portion 240 from driving portion 248, a

slight torsional bias may be required to establish and maintain a gap between the clutch portions after bare disengagement has occurred, it being understod that disengagement and separation of the clutch portions results solely from rotation of clutch throwout cam surface 243 against the stop member 244. Cooperation of roller 260 with the descending slope of the recess in the periphery of cam 233 provides the desired torsional bias.

Control of the initial rotation of cam 233 is important because very early in a cycle of rotation it controls one of the bell cranks 225 to impress upon the telegraph line the start impulse, the effect of which is to set in operation any telegraph printer connected to the line. If cam 233 should be permitted to be rotated far enough to initiate the start impulse before firm engagement of the clutch portions is established, as, for example. by frictional engagement of the tips of the clutch teeth, distortion of some portion of the signal combination to be transmitted is likely to result due to subsequent slipping of the clutch portions into firm engagement and accompanying variation in the velocity of cam 233. The immediate establishment of firm engagement between the

clutch portions

240 and 248 may be assured by exerting upon'the driven clutch portion 240 a drag suflicient to resist rotation due to frictional engagement between the teeth of the positive clutch 242. The desired drag is furnished by engagement of roller 260 with the periphery of cam 239 and particularly with the sharp ascending slope of the recess therein which roller 260 encounters substantially immediately upon the tripping of stop member 244.

Electromagnet I11 is controlled by contacts I15 and I16 which are insulatedly mounted to a frame member. Contact spring I15 carries at its free end an insulator arranged to be engaged by pin I14 mounted in the side frame I05. When the frames I05 and I06 are in the position shown in Fig. 2 with the plate II5 abutting plates I4 and I6.of the perforator, pin I14, as shown in Fig. 6, holds contact I 15 free of contact I16. Instantly that the sensing unit I0 is moved counterclockwise about its pivot, which occurs upon the operation of the perforator and the advancement of the tape therefrom, pin I14 moves free of contact I15 and contacts I15 and I16 are thereupon closed to cause the energization'of electromagnet I11. Electromagnet I 11 is thereupon energized and through its armature, withdraws latch 244 through the operation of lever 245 from engagement with stop lug 243 to allow spring-241 to move driven portion 240 rearwardly, as viewed in Fig. 1, or to the left as viewed in Fig. 4, to engage the driving portion 248 of the positive clutch. Sleeve 234 and the cams secured thereto are thereupon rotated.

Operation For the purpose of clarity, let it be assumed that all of the characters previously perforated in the tape 43 have been transmitted and that the sensing unit I0 has been moved to a position where its tape entrance channel is immediately adjacent the exit channel of the'perforator; that is, the plate II5 of the sensing unit abuts the plates I4 and I6 of the perforator. Under such circumstances, contacts I15 and I16 are opened and electromagnet I11 is de-energized, which results in stoppage of sleeve 234.

11, under such conditions, the keyboard perforator is operated through the depression of its key levers, the permutation bars 6455 will be set permutably. For each depression of the key lever, mechanism is operated for rendering clutch 95 effective, whereupon power is communicated to sleeve 96 and in turn to cam 91. The permuted setting of the permutation bars 64-65 causes a corresponding setting of interponents II through the actuation of levers H which, through the roller 13 by the action of spring 16, will be held in their set position and certain of the interponents I8 will be positioned beneath and in alignment with the punches I3. Cam 91 now being rotated causes the operation of lever 2 I, which,

through adjustable sleeve 33, operates hammer I1 and through adjustable sleeve 31 and pin 38 operates punch 39 against the action of spring 4I to perforate a feed hole in tape 43. Operation of hammer I1 causes the movement of punches I3 through the interponents I8 which have been positioned to the right, as viewed in Fig. 2, to perforate tape 43 with a transverse row of perforations symbolic of the character identified with the depression of the key lever which caused the set ting of the permutation bars 64 and 65. As hammer I1 moves vertically, stepping pawl 49 is brought into engagement with the next succeeding tooth of ratchet portion 48. As cam 91 continues its rotation, spring 6I becomes effective to restore hammer I1 and stepping pawl 49 to their normal position or the position shown in Figs. 2 and 3. The downward movement of stepping pawl 49 causes pin drum 41 to rotate in a counterclockwise direction, as viewed in Fig. 3, and advance the tape 43 a distance determined by the distance between succeeding teeth on ratchet 46.

Concurrently with the operation of the feed pawl 49, the U-shaped lever 39 is allowed to ascend under the action of spring I92, whereupon lever I81 is rotated about its pivot to move stepping pawl I83 downwardly to cause it to engage the next succeeding tooth on ratchet wheel I8I. As the hammer I1 is restored to its normal position under the action of spring 6I, U-shaped member I96 will be engaged by rod I98 and lever I81, through arm I95, will have its right-hand end, as viewed in Fig. 3. drawn downwardly, whereupon its left-hand end will be moved upwardly, carrying with it feed pawl I83 to cause the advancement of ratchet wheel I8I a distance equal to the space between its teeth, where it will be held against the action of its retractile spring I80 by holding pawl I84.

As previously described, the ratchet teeth on wheel I8I are spaced a distance less than the spacing between the rows of perforations in tape 43. Since the tape 43 is advanced by the action of feed pawl 49 through rotation of pin drum 41 and inasmuch as ratchet wheel I8I, upon operation of pawl I83, is rotated an amount such that including'the sensing fingers move less than one-tenth of an inch. Engagement between pro- ,Iection 2I1 and screw IIO i's'mairitained so that of extension 2I8 onfeed pawl I83.

The indicated movement of. the sensing unit frees pin I14'from the insulated'portion of contact spring I15 and allows the closure of contacts I15 and I16 to completethe energizing circuit for electromagnet I11. Electromagnet I draws, through pivoted lever 245, stop latch 244 from the stop lug 243 which permits driven 'portion 240 to slide, by the action of 'spring'241, into engagement with driving portion 240 of the clutch. Until the driven and driving portions of the clutch are fully engaged, rotation of sleeve v234 is prevented due to the cooperation of roller 260 with cam 239. However, when the driven and drivingportions 240 and 248 of the clutch are fully engaged, sleeve 234 rotates.

As sleeve 234 rotates,

cams

233, 239, 252, 253,

and 254 are rotated for achieving their respective functions, Cam 252 is effective on roller I10 to operate lever I69 through which arm I68 is operated to draw link I32 downwardly. As link I32 is drawn downwardly, its pin I3I cooperates with cam groove I21 to move member I26 leftwardly, as viewed in Figs. 1, 2, and 6, or away from the plates I4 and I6 it, of course, being understood that the pins I28, I29, and I30 thereof are at that instant in engagement with feed perforations in tape 43.

Due to the cam groove in member I26 a me chanical resiliency exists between the member I26 and the frame including the side members I05 and I06. Consequently, and inasmuch as the tape between the sensing unit and the perforator is taut, the side members I05 and I06 with the plate II5 move toward the exit channel of the perforator or to the right, as viewed in Fig. 2, to present the sensing fingers I25 in alignment with the transverse row of perforations in tape 43 inserted as a result of the instant operation of the perforator.

' Following the effectiveness of cam 252 or during the period of its effectiveness on link I32, a

cam 233 becomes effective on bell crank lever 225 to allow the

contacts

229 and 230 allocated to the start and stop impulses, which are normally closed, to open-to transmit a start impulse for efiecting an operation in-the receiving printer electrically connected to the transmitter previously described. Significant, of course, if the' fact that the

contacts

229 and 230 allocated to the start and stop impulse conditions are operated invariably at the beginning and near the end of the cycle of rotation of cam drum 233 to transmit, respectively, a start impulse and a stop impulse for achieving their allocated functions.

Cams

253 and 254 which, as previously described, are integral with sleeve 234 and are rotated in timed relation with cams 233, become efiective for the performance of their respective function. Cam 253 operates, through lever I64 and T-shaped lever I59 having the arms I60 and ISI, comb bail I54, which allows the sensing fingers I25 under the action of their individual springs I55, to assume positions in accordance with the code perforations in tape-43. If a sensing pin encounters a perforation in tape 43, its bell crank lever I48-I52 moves to the right, as

viewed in Figs. 3 and 6, under the action of its spring I55 to free its bell crank lever 225. As cam sleeve 234 continues its rotation, the cam 233 for the particular bell crank lever 225 which was released by the operation of bell crank ,lever I ia-I52 will allow the closure of

contacts

229 and 230 for the transmission of an impulse indicative of such setting. As the cams 233 continue through their cycle of rotation, the bell crank levers 225 will be rendered effective sequen tially'for the transmission of impulses dependent upon the position assumed by the sensing fingers I25 as determined by the perforations in tape 43. Following the transmission of the last impulse of the signalcombination represented by the transverse row of perforations in tape 43, cam 253 becomes effective for allowing, through lever I64 and T-lever I59, spring I51 to Op rate comb bail I54, to rotate the bell crank levers I48-I52 about'their pivot I41 in a clockwise direction, as

viewed in Fig. 2, and thus withdraw the sensing fingers I25 from engagement with the, tape 43 preparatory to a subsequent cycle of operation.

Cam 254, as previously described, operates, through lever I61 and in turn lever I66, member I26 which carries the pins I28, I29, and. I30. As cam 254 rotates, member. I26 is drawn downwardly through the operation of levers I66 and I61 to free pins I28, I29, and I30 from the feed hole perforations in tape 43. Concurrently, pins I2I and I22 secured to the underside of reed spring I20 engage feed perforations in tape 43 and thus hold the tape and the sensing unit against relative movement.

After the pins I28, I29, and I30 have been withdrawn from the feed perforations in tape 43, cam 252 operates, through lever I69 and arm I68, link I32 upwardly to move pin I3I in the cam groove I21 of member I26 and the straight slots in the portions I01 of the side members I05 and I06. Due to the contour of cam groove I21 and because the pins I28, I29, and I30 are then free of the feed perforations in tape 43, member I26 will be moved to the right, as viewed in Fig. 2, or toward the plates I4 and I6 of the perforator. In such a position the pins I28, I29, and I30 .are below other feed perforations in tape 43 and will engage such perforations upon the upward movement of member I26.

Cam 254 continues its rotation and due to its contour, moves member I26 through levers I66 and I61 upwardly, causing the pins I28, I29,'and I30 to' enter other feed perforations in tape 43 for repeating the operation previously described upon the initial operation of the perforator.

As disclosed in Fig. '1, pin I30 is substantially longer than pins I28 and I29 andthus will engage the under surface of reed spring I20 and move it about its pivot to free pins I2I and I22 from the feed perforations in tape 43. Pin I30 having engaged a feed perforation prior to the engagement of pins I28 and I29 with feed perforations and prior to the disengagement of pins I2I and I22 from the feed perforations, tape 43 will be held against accidental displacement and will be maintained in proper alignment with the sensing fingers I25. Also, when member I26 is lowered and the pins I28 and I29 are moved free of feed perforations and 'prior to the engagement of pins I2I and I22 with the feed perforations corresponding to those previously engaged by pins I28 and I29, respectively, pin I30 will prevent the displacement of tape 43. Such a construction insures also thatthe feed perforations will not be mutilated and also insures that the tape will be properly spaced between successive code perforations to enable the transmission of signals corresponding to the setting of the I25.

The withdrawal of pins I28, I28, and I from the feed perforations, the upward stroke of link I32, and the reinsertion of pins I28, I23, and I30 in feed perforations are achieved by their respective cams during the transmission of the code combination of impulses indicative of the setting of the sensing fingers I25.

If, during the cycle of rotation of cam sleeve 234 just describedthere has been no further operation of the key levers 82, the sensing unit remains in abutting relation with the plates I4 and I6. Pin I14 will have operated contact I15 to cause its disengagement with contact I16. The energizing circuit for electromagnet I11 is thereupon opened, and stop latch 244 is moved into the path of stop lug 243 which, when engagement is effected, the driven portion 240 against the tension of spring 241 will be moved to the right, as viewed in Fig. 4 and rotation of sleeve 234 is arrested. However, if during the cycle of rotation of cam sleeve 234 another key lever 62 or other key levers 62 have been depressed, tape 43 will be advanced through the operation of pin drum 41, in w ch case the tape 43 will be drawn through the sensin'g unit I0 by the action of member I26 and the transverse rows of perforations in the tape 43 will be sensed successively and the impulses indicative thereof will be transmitted upon the rotation of sleeve 234.

For each operation of the perforator, and particularly the punch hammer I1 through lever 2|, the feed pawl I83 will be operated and ratchet wheel I8I will be rotated step by step against the action of its spring I80. correspondingly, the lever 205 will be moved in a counterclockwise direction, as viewed in Fig. 6, and the sensing frame will follow it, thus maintaining projection 2I1 engaging screw 2I0, whereupon vertical extension 29 will be held out of the path of extension 2I8 on feed pawl I83. Such operation prevails until the'feed pawl I83 has engaged the last of the teeth on ratchet wheel I8I or is in engagement with the smooth thereof, when further advancement of the ratchet wheel IN is prevented. At such time, pin 202 will have moved along the surface 203 of arm 204 of lever 205 a corresponding movement of the sensing unit. Significant, of course, is the fact that the sensing unit, under such conditions of operation, will move away from the exit channel of the perforator for each operation of the perforator an amount less than thedistance through which the tape is advanced by the operation of pin drum 41. When the sensing unit I0 with the frames I05 and I08 has been moved to its extreme counterclockwise position, and provided the perforator is operated, the loop formed in the tape increases. Projection 201 will be in engagement with screw 2I0 and vertically extending projection 2I9 will remain out of the path of extension 2I8 of feed pawl I83.

If there is a cessation in the operation of the perforator, the cam sleeve 234 with its cams continues to be rotated, due to the fact that contacts I15 and I18 remain closed, and the mechanism for advancing the tape 43 relative to the sensing fingers I25 continues." Under such conditions, the tape will be advanced step by step through the sensing unit. However, when the sensing fingers periphery and allowed its rotation to permit tape between the sensing unit I0 and the exit channel of the perforator becomes taut, the sensing unit with frames I05 and I06 will be moved step by step along the tape toward the exit channel of the perforator.

During the movement of the sensing unit toward the exit channel of the perforator, projection 2I1 no longer engages screw 2I0,'so that member 2 is rotated in a counterclockwise direction to move vertically extending projection 2I8 of member 2I3 into the path of extension 2I8 of feed pawl I83. Should the perforator be operated under such a condition, lever- 2I will be operated by cam 81 and punch hammer I1 will be actuated to allow the operation of U-shaped member I98, under the action of spring I 92, to move feed pawl I83 downwardly. However, due to the engagement between the extensions 2I8 and 2| 9, feed pawl I 83 will be rotated in a counterclockwise direction, as viewed in Fig. 6, and will carry with it, due to projection I88, holding pawl I 84 free of the teeth on ratchet wheel I8I. Rachet wheel I8I is thus restored to normal by the action of spring I or to a position where screw 2I-0 engages projection 2I1 on side memberI05 if entrance channel of the sensing unit is not immediately adjacent the exit channel of the perforator.

With the arrangement previously described, the movement of the sensing unit is variable as compared to the advancement of the tape by the tape advancing mechanism of the perforator, which causes a loop in the tape to be formed immediately the sensing unit moves away from the exit channel of the perforator. The loop in the tape increases in size as the ratchet wheel I8I .is progressively rotated until it reaches its extreme rotative position when the loop in the tape is sizable. Such an operation does not necessitate the movement of the sensing unit to its extreme left-hand position, as viewed in Fig. 6, before a loop in the tape is formed. Consequently, the tape is relieved of strain and the movement of the tape through the sensing unit is not determined by the number of characters in storage. The tape may be moved through the sensing unit almost immediately the sensing unit is moved away from the exit channel of thepunch block inasmuch as a loop in the tape forms immedie ately, which increases in size as the sensing head moves away from the perforator.

Modification There is shown in Figs. 8, 9, and 10 a modified form of the structure disclosed in the main embodiment of the invention. According to the arrangement disclosed particularly in Fig. 8, the

movement of the sensing unit away from the per-- frame of the sensing unit. The characteristics of the spring are such as to allow the rotation of the sensing unit about its pivots an amount dependent upon the characteristics of the section of tape intermediate the sensing unit and the perforator. For example, if the noted section of tape has its area substantially perforated, then the tape is weakened materially and is incapable of moving the sensing unit away from the exit channel of the perforator against the action of the coiled spring a distance equal to the distance through which it will be moved if the noted section of tape does not include a large number of perforations.

In other words, the extent of movement of the sensing unit is controlled by the character of the section of tape intermediate the sensing unit figures of the drawings, except that its movement is not under the control of a pawl and ratchet mechanism but, as distinguished therefrom, is under the control of a spring. The transmitting unit of the embodiment shown in Fig. 8 is identical with that previously described.

As disclosed in Fig. 8, the sensing unit I includes side frames, one of which; namely, I05, is disclosed, which are pivotally mounted in side plates such as H2 and H3 and which are under the control of a spring 265 which has one end fastened to a spring post on the frame of the perforator and which has its other end secured to an eyelet fastened to side frame I65. The characteristics of spring 265 are such as to apply tension to sensing unit I6 and urge it in a clockwise direction, as viewed in Fig. 8.

Upon the operation of the perforator 9, as previously described, the tape 43 will be advanced step by step. At the beginning of an operation, the sensing unit I0 abuts the punch block of the perforator. Upon the initial operation of the perforator, the tape is advanced and the sensing unit II] with its frames such as I95, is moved in a counterclockwise direction about its pivot sufliciently to allow contact springs I15 and I16 to close due to the movement of pin I14 free of the insulated end of spring I15. The closure of contact springs I15 and I16 causes the energization of electromagnet I11 and the release for rotation of cam sleeve 234 which, during its cycle of rotation, operates the cams for actuating the rectilinear feed mechanism whereby the sensing unit is moved in a clockwise direction to a position to sense the transverse row of perforations.

Movement of the sensing unit Ill in a counterclockwise direction by the advancement of tape 43 is under the control of spring 265, which normally tends to hold the sensing unit in abutting relation to the punch block of the perforator. However, upon continued operation of the perforator, additional tape 43 is advanced and the sensing unit, under the influence of spring 265, will be moved to one of its several positions such as represented by the dotted and solid line positions, Fig. 8.

The extent of movement of the sensing unit under the influence of spring 265 will depend upon the character of the section of tape intermediate the sensing unit I0 and the perforator. For example, if such section of tape contains a large number of perforations or if the area thereof is substantially perforated, then the tape is materially weakened and the spring 265 tends to draw the sensing unit toward the perforator, with the result that a loop in the tape forms almost immediately the sensing unit I6 moves away from the perforator. Such a condition is exemplified in Fig. 9 where the sensing unit ID has moved only a short distance away from the perforator 9 due to the action of spring 265 and the fact that the section of tape intermediate the respective units contains a large number of perforations.

According to Fig. 10, the sensing unit ID has advanced away fromthe perforator 9 a distance greater than that exemplified by Fig. 9, due to the fact that the section of tape between the perforator 9 and the sensing unit III does not have its area substantially perforated and is therefore not weakened to the extent that it is incapable of overcoming the action of spring 266. The sensing unit I0, by the action of tape 43, will then be moved to a greater extent prior to the instant a loop is formed in the tape.

As the sensing unit continues to travel in a counterclockwise path the loop in the tape 43 increases. When such loop becomes sizable, it will fall over the back edge of the sensing unit I0, specifically, the frames I and I06, as shown in dotted lines in Fig. 8, and subject spring 266 to greater tension which, however, is insufiicient to move its contact free of its cooperating contact on spring 261. Consequently, the circuit for electromagnet. I11 will continue and the distributor cam sleeve 234 will not be arrested to stop transmission. However, when free advancement of tape 43 is prevented, as when it is held or becomes tangled, the tension of spring 266 is overcome and the circuit for electromagnet I11 is opened and the distributor cam sleeve will be arrested.

Electromagnet I11 is controlled by contact springs I15 and 266 engaging center contact spring 261. Disengagement of either contact spring I15 and 266 with contact spring 261 will open the energizing circuit of electromagnet I11. It is thus seen that spring 266 serves as a resilient back stop for the frame of the sensing unit. Under such circumstances, the operation of advancing the tape through the sensing head is not determined by any particular or predetermined number of transverse rows of perforations in tape 43.

Such operation continues; that is, the tape 43 will be drawn through the sensing unit and the transverse row of perforations therein will be sensed successively and the transmitting unit II will operate to transmit groups of signal impulses indicative or such rows of perforations. ever, when the loop in the tape is reduced, spring 265 causes the sensing unit to move slightly in a clockwise direction toward the perforator 9 when the tape continues to be advanced through the sensing unit.

When the loop of tape has become exhausted,

'spring 265 aided by the tension of spring 266 moves the sensing unit further in a clockwise direction toward the perforator. However, due to the characteristic of the intervening section of tape and the characteristic of spring 265, another loop in the tape 43 will be formed. Under such circumstances the tape will be advanced through the sensing unit. These operations continue until pin I14 causes contact spring I15 to disengage contact spring 261 when the circuit of electromagnet I11 will be opened and the arrest of the distributor cam sleeve efiected.

.With the arrangement shown in Fig. 8, the point at which the sensing unit moves along the tape toward the perforator is indeterminate and is controlled by the character of the section of tape intermediate the sensing unit and the perforator and the action of

springs

265 and 266.

While the several embodiments of the invention have been disclosed as applied to a particular type of apparatus, it is obvious that the invention is not limited to the embodiment of the particular apparatus because other modifications may be made without departing from the spirit and scope of the present invention.

HOW

What is claimed is: 1. In combination with apparatus for applying an unlimited number of permanent indicia on a record strip, apparatus for sensing the indicia including a plurality of sensing elements cooperating with the indicia and movable away from and toward said indicia applying apparatus as a unit, means controlled by said elements for transmitting signal impulses characteristic of their setting, means for effecting relative movement between the sensing elements and the strip to present successive rows of indicia to the sensing elements, and means controlled from the indicia applying apparatus for determining the movement of the sensing elements away from the indicia applying apparatus.

2. In combinattion with apparatus for applying an unlimited number of permanent indicia on a record strip, apparatus for sensing the indicia including a plurality of sensing elements cooperating with the indicia and movable away from and toward said indicia applying apparatus as a unit, means responsive to saidelements, a plurality of electrical contacts, a rotary cam effective through the control of said sensing elements for operating said contacts sequentially as determined by the operation of said means through said sensing elements, means to advance the strip to present successive indicia to said sensing elements and for advancing said sensing elements along the strip to a point immediately adjacent the point of application of said indicia when a predetermined condition prevails in said strip, and means controlled from the indicia applying apparatus for determining one of the directional movements of the sensing elements with respect to the indicia applying apparatus.

3. In combination with a strip perforator including code punches and a feed hole punch, means for controlling the effectiveness of said punches, means for operating said code punches in accordance with the operation of said means and said feed hole punch to perforate a strip with transverse rows of perforations and feed said strip, apparatus for sensing the code perforations in said strip including a plurality of sensing fingers movable separately and as a unit, a plurality of electrical contacts through which impulses characteristic of the perforations are transmitted, means for operating said contacts sequentially in accordance with the position assumed by said sensing fingers as determined by the perforations in said strip, means cooperating with the feed holes in said strip for moving said sensing fingers along the strip to a point to sense the last row of perforations therein adjacent the exit channel of said perforator, and means responsive to the operation of the means for operating said code punches to control the movement of said sensing fingers as a unit.

4. In combination with a strip perforator including code punches and a feed hole punch, means for controlling the effectiveness of said punches, means for operating said punches in accordance with the operation of said means and said feed hole punch to perforate a. strip with transverse rows of perforations and feed said strips, means for sensing the code perforations in said strip including a plurality of sensing fingers movable separately and as a unit, a plurality of electrical contacts through which impulses characteristic of the perforations are transmitted, means for operating said contacts sequentially in accordance with the position assumed by said sensing fingers as determined by the perforations strip, a unit including a movable frame, sensing fingers in said frame for sensing code perforations in said strip, feed mechanism in said frame cooperating with the feed perforations for advancing the strip, a pivoted lever secured to each of said fingers and responsive to their position, a

plurality of electrical contacts, a rotary distribusa-d tor operative upon the movement of said frame to operate said contacts in accordance with the position of said levers, and a cyclically operated means effective on said movable frame for controlling the extent of its movement for each operation of said perforator.

6. In combination with a perforator for applying code perforations and feed perforations in a strip, a unit including a pivoted frame, sensing fingers in said frame for sensing code perforations, feed mechanism cooperating with the feed perforations for advancing the strip, a pivoted lever secured to each of said fingers and responsive to their position, a plurality of electrical contacts, a rotary distributor operative upon the movement of said frame about its pivot to operate said contacts in accordance with the position of said levers, and means responsive to each application of code perforations to said strip to determine the extent of movement of said frame about its pivot.

7. In combination with a perforator for applying code perforations and feed perforations in a strip, a unit including a pivoted frame, sensing fingers in said frame for sensing code perforations in said strip, feed mechanism in said frame cooperating with the feed perforations for effecting relative movement between said strip and said frame, a pivoted lever secured to each of said fingers and responsive to their positions, a plurality of electrical contacts, a rotary distributor including means to operate said feed mechanism and to actuate said contacts in accordance with the position of said levers, and means efiective upon each application of code perforations in said strip to determine the extent of movement of said frame with its sensing fingers about its pivot.

8. In combination with a perforator for apply-' ing code perforations and feed perforations in a strip, a unit including a frame, sensing fingers in said frame for sensing code perforations in said strip, feed mechanism in said frame cooperating with the feed perforations for effecting relative movement between said strip and said frame, a pivoted lever secured to each of said fingers and responsive to their position, a plurality of electrical contacts, a rotary distributor including means to operate said feed mechanism for effecting the relative movement between said strip and said frame, and means for determining the extent of movement of said frame in response to the operation of said feed mechanism including a ratchet and pawl mechanism responsive to the operation of said perforator in applying code perforations in said strip.-

9. In combination with a perforator for applying code perforations and feed perforations in a strip, a sensing unit including a frame, sensing electrical contacts, a rotary'distributor including means to operate said feed mechanism and to actuate said contacts in accordance with the position of said levers, resilient means secured to said frame and controlling the extent of its movement upon the operation of the feed mechanism whereby the point at which said strip is fed by said feed mechanism through said frame is in determinate.

10. In a telegraph unit, a plurality of code punches and a feed hole-punch, means for selectively determining the code punches to be operated, means for operating the code punches and feed hole punch to perforate correspondingly a strip, means for feeding the strip a predetermined amount for each operation of said punch operating means, means for sensing the, code perforations and for transmitting signals in accordance therewith including a pivoted frame, elements in said frame responsive to the code perforations in said strip, means controlled by said elements for determining the character of the signals to be transmitted, means for effecting relative movement between the strip and said elements, and means operated cyclically with respect to the operation of said code punch operating meansfor controlling the rotative position of said frame irrespective of the number of code perforations in said strip. I

11. In a telegraph unit, a plurality of code punches and a feed hole punch, means for selectively determining the code punches to be operated, means for operating the code punches and feed hole punch to perforate correspondingly a strip, means for feeding the strip a predetermined amount for each operation for said punch operating means, means for sensing the code perforations and fortransmitting signals in accordance therewith including a pivoted frame, elements in said frame responsive to the code perforations in said strip, means controlled by said elements for determining the character of the signals to be transmitted, means for effecting relative movement between the strip and said elements, means engaging said frame when in its normal position, and cyclically operated means for determining the position of said frame enga ing means to control each movement of said frame about its pivot in response to the feeding of tape from said perforator an amount less than the amount the strip is advanced by the feed mechanism associated with the punches.

12. In a telegraph unit, a plurality of code punches and a feed hole punch, means for selectively determining the code punches to be operated, means for operating the code punches and feed hole punch to perforate correspondingly a strip, means for feeding the strip a predetermined amount for each operation of the punch operating means, means for sensing the code perforations and for transmitting signals in accordance therewith including a pivoted frame having two extreme positions, elements in said frame responsive to the code perforations in said strip, means controlled by said elements for determining the character of thesignals to be transmitted, means for effecting relative movement between the strip and said elements, and means one or its extreme'posnionsmrdreontmmn'g"thmovemeneors 13$In a-telegraph unit,"'meansffor recording signals 1 on a stri'pin the form "of" control indicia,

means for" advancing the strip with respect to the recording means, mechanism adjacent the recording means for sensing the control indicia in the strip, means for advancing said strip through said mechanism and for moving said mechanism along said strip, and means for controlling the movement of the mechanism whereby the advancement of the strip through said mechanism and the movement of said mechanism along said strip is not determined by any predetermined number of control indicia in said strip.

14. In a telegraph unit, means for recording signals on a strip in the form of control indicia, means for advancing the strip with respect to the recording means, mechanism adjacent the recording means for sensing the control indicia in the strip, means for advancing said strip through said mechanism and for moving said mechanism along said strip, and means for controlling the movement of the mechanism in a direction away from the signal recording means whereby a loop will be formed in said strip dependent upon the character of the strip intermeans for advancing the strip with respect tov the recording means, mechanism adjacent the recording means for sensing the control indicia in the strip, means for advancing said strip through said mechanism and for moving said mechanism along said strip, and means controlled from the recording means for controlling the movement of the mechanism whereby the advancement of the strip throughsaid mechanism and the'advancement of said mechanism along the strip is not determined by any predetermined number of control indicia in the strip.

16. In a telegraph unit, means for recording signals on a strip in the form of control indicia, means for advancing the strip with respect to the recording means, mechanism adjacent the recording means for sensing the control indicia in the strip, means for advancing said strip through said mechanism and for moving said mechanism along said strip, and means including a pawl and ratchet device for controlling the movement of the mechanism in a direction away from the signal recording means whereby a loop will be formed in said strip dependent upon the character of the strip intermediate the recording means and the mechanism.

1'7. In a telegraph unit, means for recording signals on astrip in the form of control indicia, means for advancing the strip with respect to the recording means, mechanism adjacent the recording means for sensing the control indicia in the strip, means for advancing said strip through said mechanism and for moving said mechanism along said strip, and means controlled from the recording means for determining that each movement of the mechanism in a direction away from the recording means will be an amount less than the amount the strip is advanced for each operation of the strip advancing means of the recording means.

18. In a telegraph unit, means for recording signals on a strip in the form of control indicia,- means for advancing the strip with respect to the recording means, mechanism adjacent the recording means for sensing the control indicia in the strip, means for advancing said strip through said mechanism and for moving said mechanism along said strip, and means including a pawl and ratchet device controlled fromsignals on a strip in the form 01' control indicia,

means for advancing the strip with respect to the recording means, mechanism adjacent the recording means for sensing the control in'dicia in the strip, means for advancing said strip through said mechanism and for moving said mechanism along said stri and means including a pawl and ratchet device operated by the recording means for determining the extent of movement of said mechanism in a direction away from the recording means.

20. In a telegraph unit, means for recording signals on a strip in the form of control indicia, means for advancing the strip with respect to the recording means, mechanism adjacent the recording means for sensing the control indicia in the strip, means for advancing said strip through said mechanism and for moving said mechanism along said strip, and means operated by the recording means for determining the extreme position said mechanism will occupy away from the recording means main upon a cessation and operation of the recording means, and means for restoring the last mentioned means in cooperation with the mechanism upon a resumption in the operation of the recording means.

21. In a telegraph unit, means for recording signals on a strip in the form oi. control indicia, means for advancing the strip with respect to the recording means, mechanism adjacent the recording means for sensing the control indicia in the strip, means for advancing said strip through said mechanism and for moving said mechanism along said strip, and a resilient member attached to said mechanism normally to urge it to abut the recording means whereby the conditions under which said mechanism is moved along said strip and the strip is moved through said mechanism by its advancing means are independent of the number of signal indicia in the strip intermediate the recording means and the mechanism.

22. In atelegraph unit, means for recording signals on a strip in the form of control indicia, means for advancing the strip with respect to the recording means, mechanism adjacent the recording means for sensing the control indicia on the strip, means for advancing said strip through said mechanism and for moving said mechanism along said strip, means for transmitting signals in accordance with the operation of said mechanism, means controlling the operation of said transmitting means, means operated upon the movement of said mechanism in a direction away from said recording means to control said transmitter controlling means to effect operation of the transmitting means, and means for causing the arrest of said transwhere it will remitting means in the event the mechanism moves to its extreme position away from said recording means.

23. In a telegraph unit, means for recording signals on a strip in the form of control indicia, means for advancing the strip with re spect to the recording means, mechanism adjacontrolling the circuit of said electromagnet and the starting and stopping of the transmitting means.

- '24. In a telegraph unit, means for recording signals on a strip in the form of control indicia, means for advancing the strip with respect to the recording means, mechanism adjacent the recording means for sensing the control indicia on the strip, means for'advancing said strip through said mechanism and for moving said mechanism along said strip, a rotary distributor for transmitting signals in accordance with the operation of'said mechanism, means controlling the operation of said rotary distributor, means operated upon the movement of said mechanism in a direction-away from said recording means to 'control said distributor controlling means to effect rotation of said distributor, and means for causing the arrest of said rotary distributor in the event the mechanism moves to its extreme position away from said recording means.

25. In a telegraph unit, means for recording signals on a strip in the form of control indicia, means for advancing the strip with respect to the recording means, mechanism adjacent the recording means for sensing the control indicia on the strip, means for advancing said strip through said mechanism and for moving said mechanism along said strip, means for transmitting signals in accordance with the operation of said mechanism, an trolling the operation of. said transmitting means, and electrical contacts one of which serves as a resilient back stop for said mechanism controlled by said mechanism' in either of its extreme positions for controlling the cir..

26. In combination with apparatus for apply ing an unlimited number of permanent indicia on a record strip, apparatus for sensing the indicia including elements cooperating with the indicia and movable with respect to said indicia applying apparatus as a unit, means controlled by said elements for transmitting signal impulses characteristic of their setting, means for effecting relative movement between the sensing elements andthe strip to present successive rows of indicia to the sensing'elements, and means operated in timed relation to the operation of the indicia applying apparatus for determining the movement of the sensing elements with respect to the indicia applying apparatus.

ALBERT H. REBER.

electromagnet con: