US2354733A - Transmitter - Google Patents

Description

Aug. 1, 1944.

E. T; BALDWIN TRANSMITTER Filed Feb. 26, 1945 2 Sheets-Sheet l INVENTOR. EDWARD T-. BALDWIN ORNEY.

Aug. 1, 1944. E. T. BALDWIN 2,354,733

. TRANSMITTER Filed Feb. 26, 1945 2 Shets-Sheet 2' FIG. 2

INVENTOR. EDWARD T. BALDWIN desirable number of sending units or areas.

Patented Aug. 1, 1944 TRANSMITTER Edward T. Baldwin,-River Forest, 111., assignor to Chicago, 11]., a corpora- Tel'etype Corporation tion of Delaware Application February 26, 1943, Serial No. 477,221 12 Claims. (01. 178-17) The present invention perta ns to printing tel'e-' graph transmitters and more particularly to control means therefor.

The principal object of the present invention is to provide a control circuit for electricaliy operated devices wherein the value of current is auto matically controlled under different operating conditions. i

Another object of the invention is to provide an improved arrangement for operating tape controlled facsimile transmitters more efficiently and economically.

A further object of the invention is to provide a means for controlling the current supplied to the stepping magnet of a tape transmitter.

Specifically, the present invention concerns the more effective control of a facsimile transmitterof the type disclosed in Patent No. 2390,0813 to E. F. Kleinschmidt. Briefly, the transmitter therein disclosed comprises a tape sensing device or record reader for sensing perforations in a tape perforated in accordance with a five-unit or Baudot code, which, through its electrical contacts, controls the energization of a plurality of electromagnets, one individual to each element of the permutation code. These electromagnets serve to control the selective position of permutation bars, which accordingly will be set in varying combinations in accordance with the code combination of perforations appearing in the perforated tape. The permutation bars for each permuted setting serve to select a pair of brushes. Individual to each pair of the brushes is a pair of code discs designed in accordance with a method of prescanning in which the characters or symbols to be transmitted are divided into any The several units and areas thus created areassigned in the order of scanning to the periphery of a code disc.

The code discs rotate continuously and the permutation bars are set permutably in response to the energization of electromagnets, as previously outlined. Energization of the electromagnets is under the control of atape sensing mechanism which receives its operating impulse from a cam operated contact which is operated in timed relation with the rotation of the code discs. For each rotation of the discs and the indicated cam, an impulse is generated to effect the energization of an electromagnet of the tape sensing mechanism to withdraw its tape sensing fingers and advance the tape to present the next transverse row of perforations in alignment with the tape sensing elements of the sensing mechanism.

- ing screw; first,

sensing mechanism through the tape to present the next transverse row of Under predetermined conditions, it is desired to arrest the operation of the transmitter or the tape sensing mechanism, and therefore, an arrangement under the control of the condition of the perforated tape is provided whereby the impulse generated cyclically through the operation of the transmitter pulsing cam will not be effective to energize the 'electro'magnet of the tape sensing mechanism to'withdraw the sensing fingers from cooperation with the tape and advance the tape.

In accordance with established practice, the tape is prepared by either a keyboard perforator or a signal controlled perforator and regardless of the manner in which the tape is prepared a section of tape intervenes between the periorator and the tape sensing mechanism. Dependent upon the condition of this intervening section of tape the impulse generated by the cam, which may be identified as the pulsing cam, is effective or ineffective.

Depending upon whether the tape between the perforator and the sensing mechanism is slack or taut, an electromagnet will be controlled for determining the position of an arm which is adapt ed to engage the threadsof a continuously rotatto engage and close contacts for establishing a condition to control the starting of the operating motor of the receivin printer at the receiving station, and second, to close contacts to render the impulse generated by the pulsmg cam effective to permit operation of the tape the advancement of perforations in alignment withthe sensing fingers and permit transmission of impulses in accord-- ance with such transverse row of perforations. Such a condition prevails as long as the tape intermediate the perforator and the sensing mechanism does not become taut.

The present invention contemplates a new ar rangement of tape transmitter pulsing me l;

anism. With the modifiedij pulsin echanism which controls the tapestepping mechanism of the tape transmitter, the tape stepping magnet is pulsed with one value of currentand maintained during idle time of the system by a lower .value of current. With the present invention, the control Y during idle circuit for the tape transmitter is such that current is impressed on the tape stepping magnet time of the transmitter as well as during operating intervals, said circuit having two resistances in series, and means comprising a screw and follower timing device and cam controlled instrumenta'lities for controlling, through the pulsing cam allows a contact in the circuit of the tape stepping magnet to open and close cyclically. This circuit contains two resistances to control plied to the tape sensing magnet. During operation of the tape transmitter, at which time the tape stepping magnet is pulsed cyclically by the rotation of the pulsing cam, it is desired to slipthe amount of current sup-- the discs 13, the dark areas of a signal or message unit being the high surfaces M to engage a brush designed to cooperate therewith to send signal impulses. It is, of course, obvious that the depressed or reduced portions of the code discs l3 represent the light areas of the signal or message unit. Obviously, the light areas might be made to be high surfaces, depending upon the preferred method of transmission and of reproduction.

The term mechanical prescanning refers to the analysis of a character in the signals suitable for transmission and comparable to the scanning of the character. The production of the mechanply a higher value of current to the tape stepping magnet by shunting out one of said resistances. Mechanism according to the present invention is provided for controlling the switching in and out of said resistance. Moreover, the arrangement acoperating coils during idle time of the transmitter.

According to another embodiment of the invention, the control magnet of a distributor is protected against overheating by controlling the,

A more comprehensive understanding of the. present invention may be had from the following description taken in conjunction with the accompanying drawings, wherein like reference characters represent similar parts throughout the several views, and in which; I

Fig. l is a schematic view of certain elements of the transmitter operatively arranged with the tape sensing mechanism and control circuit for governing the pulsing of the tape stepping magnet of the tape transmitter mechanism;

Fig. 2 shows in perspective, elements of the transmitter adaptable for the achievements A of the objects of the present invention; I 7

Figs. 3, 4, 5, and 6 areview's howing the various operating positions of the transmitter pulsing control mechanism; and V I e v Fig. 7 is a schematic view of another embodiment of the present'invention. A

Having reference to the drawings, particularly to Fig. 2, it is noted that shaft 9 has secured thereto a pinion gear l0 which meshes with a worm gear ll driven by power communicated from a continuously rotating motor (not shown). The relation between gears I 0 and H is such as to cause rotation of shaft 9 at' a speed calculated to effect the accurate and proper distribution of current impulses indicative of the characters to be transmitted. Secured also to shaft 9 are a plurality of code discs l1. 'These'code discs, as .best shown in the lower part of Fig. l, are composed of a plurality of discs arranged in pairs; that is, a pair of code discs l3 constitute 'a unit, one disc of which corresponds to a lower case character, whereas the other disc corresponds to an upper case character. V

Code discs [3 are designed accordinglto, a' method of prescanning in which characters or symbols to be transmitted are divided into any deirable number of sending units or areas. The

several unit areas thus created are assignedin.

order of scanning to the periphery of eachof cording to this invention increases the 'tape stepping margins and reduces'the heating of the .ical member or disc containing elements thereb-y correspond directly and individually to the signals and represents individual characters. For example, a character or letter may be prescanned by dividing its total area into a plurality of unit areas arranged in a predetermined number of vertical strips with a predetermined number of units within each strip. The character is'thus divided into a plurality of strips laid out in a predetermined number of equal angular sectors on the discs l3, and each angular sector is divided into a predetermined number of angular units, each corresponding to a unit area of the corresponding vertical strips. The periphery of the code discs [3 is then laid out by recessing the corresponding disc unit sections of each sector whereby the respective unit areas are light; and where the units are dark, raised surfaces M are provided. With such a plan each of the code discs 13 is correspondingly developed.

From the foregoing explanation of the arrangement of the code discs l3, it is evident that the present invention contemplates a code disc for each character or symbol to be transmitted; that is, there will be a code disc l3 individual to each letter of the alphabet and each numeral or other special characters. These code discs, being secured to, but insulated from shaft 9, will rotate therewith continuously, and during their rotation, provided a selection has been established, will effect the transmission of signal impulses indicative of their allocated character.

The discs I3 are arranged in pairs, and being so arranged, it is necessary to interconnect a disc of each pair which, in turn, are connected to a collector ring 15 which is also secured to shaft 9. Likewise, other code discs of each of the pairs of code discs are interconnected and, in turn, are connected to a collector ring [6 which, as noted for collector ring I5, is also secured to shaft 9. Interconnection of the several code discs with the collector rings l5 and i6, respectively, is achieved through the provision of conductor rods I1 and I8. These rods I1 and I8 are parallel to shaft 9 and extend through the code discs l3 and are connected to alternate code discs of each pair of code discs. Rods I1 and I8 are as shown in Fig. 1 connected to collector rings l5 and I6, respectively.

In the operation of the transmitter constituting the present invention certainfunctional operations are required. Such functional operations are performed by cams 24, 25,26, and 21 secured to shaft 9. These cams are positioned on shaft 9 with respect to each other and with respect to code discs I3 to perform their respective functions in timed relation with theother functional responses and the transmission of signal'ir'npulses as determined through'the rotation of code discs l3. It is obvious, therefore, that the cams 24, 25, 26, and 21 may be oriented on shaft- 9 with respect to each other to provide proper sequential operation in a manner fully contemplated by the present invention. I

Positioned witl'rrespect to shaft 9 and the code discs l3 are a plurality of permutation bars 3|, 32, 33, 34, and 35, one individual *to each element of the code. According to the embodiment of the invention disclosed, a'five-unit code is implied, and therefore there are five permutation bars, or one individual to each element or unit of the code. Operation of the permutation bars is attained through the arrangement of an electromagnetindividual to each of the bars. Under such circumstances there are five electromagnets 37, 33, 39, 40, and 4|. These electromagnets are selectively controlled from a tape sensing mechanism 43 andcontrol, through their armature, a spring-held latch 44 which engages a shoulder formed on the upper edge of its permutation bar to hold it against the action of its individual spring (not shown).

The tape sensing mechanism 43, as is fully and completely disclosed in Patent No. 1,460,357 to E. E. Kleinschmidt of June 26, 1923, embodies a plurality of tape sensing fingers 41 which serve to set perforations in a tape 48, which has been perforated through the operation of a keyboard perforator or a signal controlled reperforator to form transverse rows of code perforations in dicative of the characters or symbols of the message to betransmitted'through the effectiveness of code discs l3. As is fully disclosed in the afore-mentioned patent No. 1,460,357, sensing fingers 41 are pivoted on a rod 49 and are movable about such rod by an electromagnet 50. Specifically, electromagnet 50, upon being energized, draws itsma-gnetic yoke 5| to shift its core axially topusha nonmagnetic pivoted bail plateli'z against the five tape sensing fingers 41 and thus withdraw the sensing fingers 41 from engagement with the perforations in tape 48 and causes,

following such withdrawal, the advancement of the tape through a ratchet and pawl mechanism (not shown) to present the next transverse row of perforations inalignment. with the vertically projecting pins of the sensing fingers 47., The magnet core of the electromagnet 50 is, of course, so designed as to respond in well-known manner to the energization of said magnet, and said core is providedwith nonmagnetic extensionswhich engage the bail 52.

Attached to and operated'by each of the sensing fingers. is a contact spring 54. There being five sensing fingers 41, there are five contact springsv 54 which cooperate with stationary contacts 55 tonefiect a circuit closure and cause,

through the instrumentality of a battery, the energization of the electromagnets connected thereto; that is, electromagnets 31 to 4|,

Assume, for example, that a sensing finger 4T encounters a perforation in tape 43. Through its contact spring 54 an energizing circuit for the electromagnets 31 to 4| connected thereto will be established. The electromagnet will be energized and latch 44 will be operated againstthe action of its spring to free the permutation bar individual thereto for action by its spring. (not shown). Such permutation. bar will be moved. to theleft as viewed in Fig. 1. 7

Under certain conditions of operation, it is desirable to prevent the operation of the tape sensing fingers 41, notwithstanding the fact that the electromagnet 50 may be energized cyclically.

In order to achieve such a result, a control circuit for the transmitter pulsing mechanism is provided whereby, notwithstanding the. fact that is mounted on shaft 9. cam 24, bail I6 will'have its knife-shaped porshunte'd'outautomatically thereby increasing: the

current supply to the magnet 55 duringrzeach cyclic rotation of the pulsing. cam '21; '5 This-are rangement will --be described morefully herein+ after;

As shown in Figsg- 1 and 2, the lower 'edgefiof each of thepermutationbarsfl .to 35 is-formed Avith a plurality of notches arranged permutably so that-upon the perm'ute'dioperation ofelectromagnets3'! to 4 l corresponding operation of permutation bars 3| to.35'will result .inanialignment of-n'otches to effect the selection of one 015a plurality of selectable bars 6| There is a select able bar 6| individual to each pair of code discs l3. Each selectable bar BI is individual to a: brush carrier or support 63 (Fig. '2) carrying a pair of brushes 65 and 66 for each pair of code discs-l3.

Each of the brush supports 63 has formed on oneof its arms a horizontal projection 61 which lies in the path of its individual selectable bar 6 sothat upon the operation of its bar 6|,brush support 63 will be'rotated in a clockwise direction about rod 64, asviewed in Fig.2, against the actionof itsretractile spring:68,:.provided, however, the brush support 63 is at that instant free to move. As shown in Fig. '2-,'the" brush sup;- port 63 has a horizontal extension 69 arranged with its end formed in a knife-like fashion-to cooperate: with a corre'spondinglyshap'ed portion of a bail'lfl which extends transversely of the code discs [3 and which is pivotally supportedat its ends by brackets H and 12. Formed near the left-hand end of bail I0 is a projection 13 to which is attached a. retractile spring 14 and a pivoted lever 16 which carries at its free end a .cam roller. 1'! positioned to be operated cyclically by'cam 24 which as previously described, Foreach operation of tion moved free of the correspondingly'shaped projection 69 of the brush carrier 631:0 release thebrush carrier 63, whereupon it is restored to its normal position orthe position shown in Fig. 2, by the action of its individual retractile spring 68.

Common to all selectable members 6| is a bail flit-which is pivotally mounted on rod 64 and which has vertically projecting arms. 45 "and.46

to which cam rollers operatively positioned with respect to cams 25 and-26,. respectively, are secured. Retractile-springs 59 and 60 are secured to arms .45. and 46, respectively. .For each rota,- tion of cams 25 and 26; bail will be rotated counterclockwise, as viewed in Fig. 2, against the tension of springs 59'and 60 to move the selectable bars 6i free of the permutation bars 3| to 35 to permit their operation, and. subsequently-will release the selectable bars 61 to permit one of such bars to be selected through the alignment of a set ofv notches in permutation bars 3| .to 35.

Whenthe permutation bars 3| to35 arepositioned in various combinations .in response to the permuted energization of electromagnets 31 -free-of extension69 of its brushcarrier 63.. -.The

brushsupport.63.individua1 tothe operated sele'ctablebar 6I will be moved againsttheaction of'its spring 68 to bring. the brushes 65 and66 into operative relation with. respect to the pairjof code discs I3 to which the operatedv brushsupport 63 is individual. Following the setting of the brush support 63, looking bail 10 is restored by its spring .14 to a position where it engages extension 69 of brush support 63 and holds such brush support in its set position. The selectable member BI is thereupon free to be restored to its normal position out of cooperation with the permutation bar 3| to 35 through the action of bail 80,. and thus thepermutation bar may be reset to select either the same selectable bar or another selectable bar v 6I identified withanother pair of code discs I3. With .suchan arrangementrit is possible tofinitiate a selection during the interval the brushes 65 and 66 are in engagement with the code discs I3 for the transmission of signal impulses characteristic of their peripheral formation. a

Following the selection of a selectable bar GI and the operation ofthe brush support 63, a cam (not. shown) mounted on shaft 9 is effective to operate through a system of levers as fully disclosed in Patent No. 2,176,740 to E. E. Kleinschmidt of October 17,1939, to restore each of the released permutation bars 3| to 35 to their normal position, or the position shown in Fig. 1, wherein thebars are held against the action of their individual springs byv latches 44.

As previously described, a code disc I3 of each pair of code discs isuconnected to collector rings I and I6, respectively. Continuously in engagement with each of these rings are brushes 82 and83, respectively (Fig. 1). These brushes are connected-through electrical conductors to contacts 84 and 85. Cooperating with these contacts is a contactor 86 pivoted at one end and engaged at its other end with a rockable member 81. Secured to member 81 are two oppositely arranged bell crank levers 88 and 89 arranged to move member 81 to the left or right, depending upon whether bell crank lever 88 or bell crank lever 89 is operated, to cause corresponding movement. of contactor 86 to engage either contact 84 or contact 85.

Operation of hell crank levers 88 and 89 is achieved through selector bars 90 and 9| individual thereto. Upon the selection and operation .of either of the selectable bars 90 and 9Iithe bell crank lever 88 or 89 individual thereto will be operated and corresponding movements of member 81 will .be effected in well-known manner. Specifically, the selectable bars '90 and. 9|

identified withithe figures" and letters or shift-and unshift signal combinations, respectively, and in accordance with the selection of thebars 90 and 9I, the bar'81 will be shifted '.to switch the. arm. 86 into contact with contacts:

84 or 85 which will thereupon connect the collector ring I5 or It to the signal line, it being understood'that certain of the bars I3 are connected to the collector ring I5 and other of the bars of'discs l3 are connected to the collector ring I6, hence theefiective circuit'wi-ll depend upon-the positionofcontac'tor 86, which; as shown in Fig. 1, is connected to a radiolfrequency transmitter 18 which may be of any well-known design.

Positioned near the entrance end of the tape sensing mechanism 43 is a mechanism commonly referred was a taut tape switchingrm'echeinis'm which'responds to the condition of 'the tape -to exercise control functions. Such a'mechaits free end engages an insulated block secured to the free end of an electrical contact 96 which cooperates with an electrical'contact 91 to control an electrical circuit which extends from battery through a manually operated switch 99, contacts 9691 and the windings of an electromagnet I03 to ground. Of course, with the switch 99 open, the circuit for electromagnet I03 will not be completed; also, with contacts 96 and 91 open and with switch 99 closed, the circuit of electromagnet, I03 will not be completed. However, with the lever 93 in the position shown in Fig. 1, which is its position when the tape 48 is looped as shown, contacts 96 and 91 will be closed, and with switch 99 closed electromagnet I03 will be energized.v Q

As disclosed in Fig. 2, electromagnet I03 has its armature I04 pivotally mounted in a bracket I05 and held in its released position by a spring I06. Pivotally attached to armature I04 is a vertically extending lever I01 which is moved to the position shown in Fig. 2, by a spring I08 which has one end secured to arm I01 and the other end secured to a fixed spring post. Secured near the free end of arm I01 is a pin or .worm follower I09 which, when electromagnet I03 is energized, engages the threads of worm 30, which as disclosedin Fig. 2 is formed in the left-hand end of shaft 9.

The upper end of arm I01, as disclosed in Fig. 2, is beveled and is arranged during its movement from right to left, as viewed in Fig. 2, when electromagnet I03 is energized and when follower I 09 will be in-engagementwith the'thread of worm 30, to operate successively contacts H2 and H3. The contacts 2 and H3, as more 'fully' disclosed in copending application Serial No. 371,358 filed December 23, l940,-by R. E. Zenner, function to generate signal conditions which will cause operationof-the radio transmitter 18 to transmitto the radio receiver 19 a signal effective to control the operating circuit of the driving motor of the receiving printer which is connected to the radio receiver network 19.

The electromagnet 50 is included in a circuit extending from battery, through the winding of the magnet 50, over conductor II6, through resistanc'es H1 and H8, over conductor H9, and then through contact I2I (closed cyclically by cam 21) to ground. When the magnet I03 is energized upon the closing of switch 99 and tape switch contacts 96-91, as previously described, its armature I04 is attracted to bring the pin I09 on arm I01 into engagement with the threads of the worm 30, and since the. worm 30 is constantly rotating, the arm I01 will be advanced toward tromagnet I23 to ground.

When the magnet I23 thus becomes energized, itiwill pull up-its armature I24 against the action of a spring I25. Armature I24 and. a lever cuit for magnet 50 extending from positive bat- I I2Ii control the opening or n on-opening of the pulsing contact I2I upon the rotation of cam 21. Lever I26 is mounted on pivot I2I, as is also a control lever I28. Armature I24. is provided with an extension I29 carrying at its upper'end a screw I3I which functions, upon the attraction of armature I24 by magnet I23, to close a contact I 32 included in a shunt circuit around the resistance II8. Lever I28 is normally biased in a counterclockwise direction by a spring I33, and is provided with a lower horizontal arm, the free end of which cooperates with the left-hand spring of contact I32 in such a manner that when contact I32 is open, its left-hand spring acts to block or prevent the counterclockwise rotation of lever I28 by spring I33. Then, when the armature I24 pulls up, it causes the screw I3| to close contact I32 which frees the left-hand spring of contact I 32 from engagement with arm I34 to permit counterclockwise rotation of lever I28 by spring I33 to the position shown in Fig. 6. In the position shown in Fig. 6, the lever I28 acts to lock the contact I32 closed against premature opening, which opening is governed, upon the deenergization of magnet I23, by the cam 21 acting upon the horizontal arm I35 of lever I28 so that the lever I28 is thereupon rotated clockwise to bring the arm I34 again under the left-hand spring of contact I32.

The upper spring of contact I2I is provided with an insulating portion which cooperates with lever I26 which in turn is adapted not only to cooperate with cam 21 but also to have latching relation with armature I24 of electromagnet I 23. With this arrangement, the armature of magnet I 23 under certain conditions of operation is latched behind (or to the left of) the latching projection on lever I26 (as shown in Fig. 5) so that the armature I24 cannot move toward the pole piece of magnet I23 (upon energizae tion of said magnet) until cam 21 rotateslever I26 counterclockwise to raise the latching end thereof free of armature I24, With this construction, it would be possible to withdraw the armature I 24 of magnet I23 from under lever I26 at any point in the operating cycle and'therefore open the circuit to the tape stepping magnet 50 at an improper instant in the operating cycle. With the armature of magnet I 23 obstructed by a projection on lever I 26, however, the armature I24 cannot be removed from under the latching projection of lever I26 until this ob-. struction is removed by the proper positionment of cam 21 and this action provides the proper timing in the operating cycle. Some lost motion is provided between the lug I31 on lever I29 and contact IZI, whereby contact I2I-will not be opened unless armature I24 is removed from blocking relation with lever. I25 (as shown in Figs. 3 and 6) i/Vhen the lever I26 and the cam- 21 are in the relation with each other as shown in Figs. 4 and 5, wherein these elements are shown in different blocking relation with the armature I24, the contact I2I willremain closed,

General operation In the operation of the. apparatus according to the present invention, the arrangement is shown in Fig. 1 in its idle condition. Upon closing the manual switch 99 (assuming that the contacts 969'I are closed due to the presence of a loop in the tape 48, and further assuming that the transmitting shaft 9 is continuously r tating thus imparting rotation to cam 21) the contact I 2| will be operated cyclically, the cirtery, through the winding of magnet 50, over the conductor II6, through the resistances Ill and H8, and through contact I2I (when closed) to ground. With the two resistances H8 and II! in the circuit, the value of the current flowing therethrough is not of sufficient strength to energize the magnet or solenoid 50. Thus, in this condition of operation, the contact I2I will be constantly opened and closed, but the solenoid 50 will not beoperated. Moreover, in this condition of operation the solenoid 50 is independent of the manually operated, switch 90. However, when theswitch 99 is' closed, and assuming that the tape control contactsSB and 91 are also closed, a circuit will be completed from battery, through the switch 99, through contacts 96'9'I, over conductor I I 5 and through the magnet I03 to ground. Upon energization of magnet I03 its armature I04 will be attracted to bring the pin I09 on arm I01 into engagement with the threads of the worm 30 thus causing the arm I0'I, to travel leftwardly until it closes the contact H4, whereupon a circuit will be completed from positive battery, through the contact II 4, over conductor I22, and through the winding of magnet I23 to ground. Upon energization of magnet I23 its armature I24 will be attracted, thus causing the screw I3I on the extension I29 to close the contacts I32. However, this closure of contact I32 will not occur until the cam 21 has reached its proper an, gular position with relation to the lever I26, so that the notched right-:hand end. thereof is clear of the armature I 24, thus permitting the armature 124 to be pulled up completely by the magnet I23. When the armature I24,ha s been completely pulled up and the contact I 32 has been closed the arm I34 of lever I20 will be free to be rotated counterclockwise by the spring I33, thus locking the contact I32 closed for'at least the ensuing cycle of rotationi'of carn .21. After" came 21 has i rotated 'a predetermined amount it will cooperate with the arm I35 of lever I28 -to impart clockwise rotation to said lever I28 against the action of spring I33 to attempt to bring the arm I34 under the lefthand spring of contact I32, but if the magnet I23 is' still energized, the contact I32 Will stillbe held closed, and the lever I28 will merelyoscillate back and forth under the action of the cam 21. 7 Thus, the lever I26 will bear a relation with the armature I 24, as shown in Fig.3, wherein the lever I26 is' rocked counterclockwise andv clockwise by the cam 21 under the influence, of spring I36. In this-connection it is noted that the lever I26 is providedwith a laterally pro- J'ecting lug; I3'I which cooperates with the insulated portion of contact I2 I'so that, as the cam 21 operates upon the lever I26" to urge it to' its extremecounterclockwise position against the action of spring I36, the contacts I2I will be per mitted to" close due to their own spring tension, and the lug- I 31 will be moved free of the insu lated portion. It is noticed that there is sufficient lost'inotionbetwe'en' the lug I 31' and the insulated portion so that a certain degree of oscillation of lever I20 is permissible while it is held'i'n the position'shown in Figs.'4 and 5.

As the contacts I32 have now become closed, the resistance H8 is shunted out of theenergiz ing circuit forthe solenoid 50, thus permitting an increased value of current to flow through the energizing circuit therefor, and accordingly upon each closureof contacts I2I by the cam 2'I the circuit will extend from ground, through contacts I2I, over conductor II9, through con-' tacts I32, through resistance II1, over conductor H6, and through the winding of the solenoid 50 to battery. Therefore, upon each rotation of the cam 21 which constitutes a pulsing opera tion for the solenoid 50, said solenoid will be energized to cause the feeler arm 41 to sense the perforations in the tape 48, thus closing the con-, tacts 54 and 55 according to the code combination sensed in the tape and, in turn, causing the energization of corresponding magnets 31 to 4I, and unlatching the corresponding latches 44 to permit the code bars 3| to 35 to be set ac-' cordingly to permit the selection of a selectable bar 6|.

This operation will be repeated successively until the taut tape switch 96-91 has been opened by a taut or tight condition in the tape 48 (or by the opening of the manual switch 99), whereupon the magnet I03 will become de-ener-. gized, and upon release of its armature I04 the arm I01 will withdraw the pin I09 from the 205, through resistance 206, through 204, through switch 201 4 its armature 203, and armature 203 has opened the shunt contacts 209, current of lower value will thereafter be impressed upon the winding of magnet 204, due to the introduction of resistance 206 into its energizing circuit. This current of lower value is of sufiicient strength to permit the worm thus permitting the spring I08 to draw the arm I01 away from the contacts II4 opening the same and breaking the energizing circuit for the magnet I23. Due to this de-energization of magnet I23 the armature I24 will tend to re-- spond to the pull of its spring I25 to move away from the magnet I23. However, this movement of armature I24 is delayed by the lever I26 until the cam 21 has rocked the lever I26 sufficiently counterclockwise to permit the armature I24 to escape the latching end of the lever I26, thus causing the opening of contact I32. Then. when the cam 21 operates upon the arm I torotate the lever I28 clockwise, the arm I34 will be brought underneath the left-hand spring of contact I32 and thelever I28 will be held in this, clockwise position against the action of spring I33 until the magnet I23will again become energized. The resistance I I6 will again be introduced into the energizing circuit for the solenoid 'due to the opening of the contacts I32, and hence insuflicient current will be supplied there-- after to the solenoid 50 to prevent operation of the solenoid 50 and the tape sensing mechanism until a condition is created whereby the magnet I03 is again energized.

In Fig. '1 is illustrated a further embodiment of the present invention, wherein the magnet of a distributor is protected against overheating. In Fig. '7, the distributor 20I is provided with a brush arm 202 which cooperates with an armature 203 of the magnet 204. The energizing circuit for magnet 204 extends from positive battery, over conductor 205, through resistance 206, then through the coilsof magnet 204, through switch 201, to negative battery. A shunt circuit is provided around resistance 206, including conductor 208, shunt contacts .209 and conductor 2I I. When the magnet 204 is de-energized, its armature 203 is biased by spring 2I2 into the path of brush arm 202 to prevent rotation thereof.

Upon closure of switch 201. an energizing circuit for magnet 204 is completed from battery, over conductors 205 and 208, through contacts 209, over conductor 2| I, through the winding of magnet 204, through switch 201, to negative battery As the magnet 20 4'becomes energized, it pulls up its armature 203, and in so doing, the armature 203 acts to open the contacts 209 and thereby remove the shunt around the resistance 206, after which the energizing circuit for magnet 204 will extend from positive battery, over means well as during operating intervals, said circuit magnet 204 to hold its armature 203 attracted. Moreover, this holding current is not of sufficient strength to overheat the coil of magnet 204. Thus, with the present invention, an arrangement is provided for permitting sufiicient current to be supplied to magnet 204 to permit it to perform its predetermined operation, and thereafter to reduce the value of said current by automatically introducing in the circuit a resistance of suflicient size to maintain the magnet 204 energized as long as it is desired to have the distributor 20I operate.

The invention has herein been described in a particular embodiment thereof. It is understood, of course, that the invention may be applied to other forms of apparatus without departing from the spirit and scope of the present invention, as defined by the appended claims.

' What is claimed is:

1. In a telegraph system, a transmitter having a record strip feeding means, a control circuit therefor wherein current is supplied to the record strip feeding means during idle time of the transmitter as well as during operating intervals, said circuit having two resistances in series, and means comprising a screw and follower timing device and cam controlled instrumentalities for controlling'through an electromagnetically operated switching device, the shunting in and out of one of said resistances to vary the value of current supplied to said record strip feeding means. 7

2. In a telegraph system, a transmitter having a record strip feeding means, a signal line, means for rendering said transmitter effective to transmit control impulses over said line including means responsive to the condition of the record strip, a control circuit for said feeding means wherein current is impressed on said feeding during idle time of the transmitter as having two resistances in series, means controlled by said second mentioned means for rendering said record strip feeding means effective to transmit character signals over said signal line, and cam controlled instrumentalities for controlling, under the control of said second mentioned means, the shunting in and out of one of said resistances to vary the value of current supplied to said feeding means.

3. In a transmitter having strip feeding means, a control circuit for said means, pulsing means in said circuit, a plurality of current controlling means in said circuit, shunting means for certain of said controlling means, a supervisory circuit arrangement, and cam controlled instrumentalities effective in cooperation with said supervisory circuit arrangement for controlling said shunting means for varying the value of current supplied to said strip feeding means.

4, In a transmitter having tape feeding means,

a control circuit for said means, pulsing means in said circuit, a plurality of current controlling means in said circuit, shunting means for certain of said controlling means, a first cam controlled means for governing the operation of said pulsing means, and a second cam controlled instrumentality for controlling the operation of said shunting means for varying the value of the current supplied to said tape feeding means.

5. In a transmitter having tape feeding means, a control circuit for said means, pulsing means in said circuit, a plurality of current controlling means in said circuit, shunting means for certain of said controlling means, an electromagnetically controlled means, a first cam operated means for governing, under the control of said electromag netically controlled means, said pulsing means, and a second cam operated instrumentality for operating said shunting means forvarying the value of current supplied to said tape feeding means,

6. In a transmitter having strip feeding means, a control circuit for said means, pulsing means in said circuit, current controlling means in said circuit, shunting means for said controlling means, timing means, and cam controlled instrumentalities effective in cooperation with said timing means for controlling said shunting means for varying the value of current supplied to said strip feeding means.

7. In combination, a first circuit including a magnet, an armature for said magnet, means for establishing said circuit, a second circuit comprising pulsing means, current controlling means and an operating magnet, said operating magnet normally ineffective, shunting means for said current controlling means controlled by said armature, and cam controlled means effective in response to the operation of said armature upon the establishment of said first circuit for jointly maintaining said shunting means effective to shunt said circuit controlling means to render said operating magnet responsive to said pulsing means.

8. In a transmitter having tape feeding means, a control circuit for said means, pulsing contacts in said circuit, constantly rotating cam means for successively operating said pulsing contacts, current controlling means in said circuit, shunting means for said controlling means, timing means, and cam controlled instrumentalities effective in cooperation with said timing means for controlling said shunting means for varying the value of current supplied to said strip feeding means irrespective of the successive operation of said pulsing means.

9. In a transmitter having strip feeding means, a control circuit for said means, pulsing means in said circuit, a plurality of current controlling means in said circuit, shunting means for certain of said controlling means, timing means, and cam controlled instrumentalities effective in cooperation with said timing means for controlling said shunting means for varying the value of current supplied to said strip feeding means.

10. In a transmitter having tape feeding means, a control circuit for said means, pulsing contacts in said circuit, a current controlling means in said circuit, shunting means for said controllin means, a supervisory circuit arrangement, and cam controlled instrumentalities effective in cooperation with said supervisory circuit arrangement for controlling said shunting means for varying the value of current supplied to said strip feeding means.

11. In a transmitter having tape feeding means, a control circuit for said means, pulsing contacts in said circuit, constantly rotating cam means for successively operating said pulsing contacts, current controlling means in said circuit, shunting means for said controlling means, a supervisory circuit, and cam controlled instrumentalities effective in cooperation with said supervisory circuit for controlling said shunting means for varying the value .of current supplied'to said strip feeding means irrespectiveof the successive operation of said pulsing means.

12. In a transmitter having tape feeding means, a control circuit for said means, pulsing contacts in said circuit, cam means for operating said pulsing contacts, current controlling means in said circuit, shunting means for said controlling means, a supervisory circuit including an electromagnetic device for operating said shunting means, means controlled by said cam for governing the effectiveness of said electromagnetic device, and further means controlled by said cam and effective under the control of said electromagnetic device for controlling said shunting means for varying the value of the current supplied to said strip feeding means.

EDWARD T. BALDWIN.

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