US2323932A - Telegraph printer - Google Patents

Description

July 13, 1943. L. M. PoTTs 2,323,932

TELEGRAPH PRINTER Filed May 9, 1940 4 Sheets-Sheet l FIG. I

INVENTOR. LOUIS M. POTTS ATTORNEY.

July 13, 1943. L. M. PoTTs 2,323,932

TELEGRAPH PRINTER Filed May 9, 1940 4 Sheets-Sheet 2 FIG. 8

INVENTOR LOUIS M. POTTS A RNEY.

July 13, 1943. PQTTS 2,323,932

TELEGRAPH PRINTER Filed May 9, 1940 4 Sheets-Sheet 3 IN VENTOR. LOUIS M POT TS A TTORNEY.

y 1943. L. M. POTTS 2,323,932

TELEGRAPH PRINTER Filed May 9, 1940 4 Sheets-Sheet 4 FIG I?) FIG. I I (D CODE OOMBINAHON SHIFT STOP RECEIVING snmorq INVENTOR.

LOUIS M. POTTS ATTORNEY.

Patented July 13, 1943 TELEGRAPH rnnv'rna Louis M. Potts. Evanston, Ill., assignor to Teletype Corporation, Chicago, Ill., a corporation of Delaware V Application May 9,

12 Claims.

The present invention relates to printing telegraph apparatus and more particularly to type wheel printers having a. plurality of printing posltions,

The principal object of the present invention resides in the provision of printing and selecting apparatus designed to enlarge the range of selective possibilities without extensive modification of fundamental practices in printing telegraph selecting apparatus and without having to change the essential mechanism.

The use of a plurality of case shift signals in controlling the operation of telegraph printing apparatus is generally known but certain novel aspects herewith introduced have to do with a conversion system for adapting existent practices in design and manufacture of type wheel printers to the use of a greater number of case shift control functions. As an incident to this practice, there is contemplated under one embodiment the utilization of a six-unit code for the supervision of apparatus constituted essentially of a five-unit selection and control mechanism, the presence or absence of the sixth impulse being a determining factor in establishing a secondary case shift control while the conventional pair of case shift signals are utilized additionally to the said sixth impulse case shift control for performing the primary case shift supervision. As a result, four instead of only two case shift conditions are provided, and these with but minimum modification in the essential design of a type wheel printer, such as that disclosed in copending application Serial No. 193,642, filed March 3, 1938.

In a type wheel printer of the design herein contemplated, the type wheel carrying shaft is a frictionally driven member surrounded by a number of parallelly disposed selector pins. A shaft stop arm engages one of these pins when any of the latter is brought into selective condition established by an individual disposition of five selector discs, each provided with peripherally disposed notch and lug attributes, and the several adapted to be moved in response to the selective operation of a line signal supervised transfer mechanism.

In addition to carrying the type wheel and accordingly positioning the latter angularly so as to present predetermined type faces into printing position, the type wheel carrying shaft is also utilized for supporting and rotating with it divers incidental function performing interponent elements. when certain one or ones of said elements are arrested in predetermined an- 1940, Serial No. 334,108

gular positions as controlled by the type wheel shaft arresting apparatus, there are conditioned corresponding one or ones of several function performing levers for executing miscellaneous incidental operations; viz.', primary case shift. carriage return, etc.

An additional set of case shift control functions identified as secondary to the conventional case shift operation is contemplated such that their incorporation into existing apparatus may permit of an enlargement of several selective possibilities to an extent of doubling the available selective possibilities based on previous practice.

For a more comprehensive understanding of the present invention, reference may be had to the accompanying drawings and to the detailed specification following hereinafter in which similar reference characters indicate corresponding parts throughout, and in which:

Fig. 1 is a vertical sectional view through a printing telegraph apparatus, such as that featured in the copending application mentioned above, having incorporated therein the improvements which exemplify one embodiment of the instant invention;

Fig. 2 is a plan sectional view taken approximately on line 2-2 of Fig. 1;

Figs. 3 to 8 are detailed views of the case shift determining apparatus featured in Figs. 1 and 2;

Fig. 9 is a schematic diagram of a first modiilcation of the invention which utilized plus, minus, and no-current for signal composition with the marking impulses varying between positive and negative current characteristics for the purpose of obtaining a shift control index;

Fig. 10 illustrates a modified form of shift mechanism especially adapted for use in a system such as that featured in Fig. 9;

Fig. 11 is a fragmentary plan section of a second modification apparatus;

Fig. 12 is a schematic diagram of a system which uses an apparatus of the type shown in Fig. 11 in which the signals are of conventional length, but in which a sixth impulse is incorporated with the stop interval and the start impulse is varied to contrast with the stop impulse; and

Fig. 13 is a diagrammatic chart of a code signal such as may be used in the system disclosed in Figs. 11 and 12 showing how its component parts are functionally allocated.

In illustrating the preferred embodiment of the present invention, Figs. 1 to 4, a type wheel page printing machine is used whose selector shaft is maintained in a vertical position, and at whose upper extremity is carried a cylindrical type supporting wheel having individually movable printing pallets. This type wheel indicated ii is provided with four annular rows of type pallets I2, each pallet of which is radially slidable within its own confining groove. and each annular row of which is retained and urged towards the concentric center of the wheel by a garter spring IS. A cylindrical printing platen I4 is Journaled upon a supporting shaft I5 and is shiftable endwise step-by-step in one direction in response to printing operations, and totally in the other direction in response to a carriage return signal in a manner well-known among page printing machines.

The platen i4 is supported in a carriage generally indicated it which may itself be supported and confined by antifriction rollers il confined between the trackways l8 and iii. In front of the printing platen l4, there is indicated a printing ribbon 2|, the location of which, with respect to the periphery of platen i4, is indicative of the printing locus and, accordingly, denotes the level at which each row of printing pallets must be aligned in order to present it into printing engagement with said platen i4.

The type wheel ii is integrally associated with a supporting collar 22, and is splined to rotate with the type wheel shaft 23 but free to be shifted longitudinally thereof together with its collar 22. This longitudinal shifting of type wheel II is executed through engagement of a shifting frame 24 whose horizontal bar 25 is slotted as at 26, Fig. 2, to straddle and be received within the groove 21 of collar 22. For purposes of steadying the shifting frame 24, its bar 25 is provided at remote ends with yokes 28, Fig. 2, of which one is visible in Fig. 2, and which is indicated thereat 28 straddling the supporting column 29, parts 28 and 29 being duplicated at the opposite end of bar 25, but being broken away in the limited disclosure of Fig. 2.

Collar 22, Fig. 1, is prevented from rotating with respect to shaft 23 by the interengagement between its slide engagement coupling bar 3| with that 32 of a selector arm sleeve 33. Because of the tongue and groove engagement between arms 3i and 82, type wheel ii, together with its collar 22,-may be shifted longitudinally, without disengagement of driving connection between said elements Ii and 32, but permitting, nevertheless, of axial shifting of the type wheel and its associated elements throughout a distance sufilcient to-elevate the type wheel to the dotted outline position (of Fig. 1) while still maintaining the driving and driven relationship between the selector arm sleeve 33 and the type wheel ll.

Sleeve 33 and its integrally associated selector arm 34 are bound to the shaft 23 so as to rotate with it under impetus of the driven gear wheel 45 which maintains meshing engagement with the motor driving worm 36, but because selector arm 44 may be obstructed by one or another of the plurality of selectable pins 31, the assembly, including shaft 23,may thereby be arrested at any one of several radial positions corresponding with the several selectable pins 31. In passing,mention is made of the scant showing of a selector pin assembly in Fig. 1. Actually this apparatus consists of possibly thirty-two pins 41 all similarly held and the several closely placed in a circular group about shaft 23 as a center. The single pin I! illustrated in this figure denotes the relative position, but the others of the selector pins as well as certain supporting apparatus has been eliminated from view in order to render more clear for observation that mechanism which is directly concerned with the present improvement.

when shaft 23 is so arrested, driven wheel ll may continue to rotate, but slippage is permitted between the latter and its adjacent driving discs 38 and 89 because of the intervening slip washers 4i, fibrous elements which are tensioned between the adjacent surfaces of gear wheel and said discs 88 and 39. As explained in greater detail, in the above referred to copending application, the rotary drum selector which includes the above-mentioned selectable pins 81 is designed to accommodate a five-unit code having as its essential selector apparatus five circular discs 42 whose peripheries are provided with a notch and lug distribution. so that upon each permutative placement of the several discs 42 an individual clearance is afforded to one of said several selectable pins 81 which, when that occurs, moves inwardly to present its upper extremity, Fig. 1, into the path of rotatable arm 84, blocking the further progress of said arm and through it the r0- tation of shaft 23.

This selection, arresting shaft 23 in any of thirty-two rotary positions, may not only serve to align a corresponding printing lug l2 for subsequent printing operation, but also, because shaft 23 is a carrier of other selecting apparatus, it may serve to condition special function operating members as more fulhr described in said copending application. Of these special functions, certain ones only are concerned in the instant disclosure, and these will be identified as the two primary case shift functions; namely, the conventional upper and lower case shifts. In Fig. 1, the two selectable bars which execute these case shift functions are illustrated in the lower portion of the figure by the reference numerals 43 and 44, the former having a sidewardly extending lug 45, and the latter a similar lug denoted 46.

The apparatus now described is that which, in response to the two conventional case shift signals, exercises a part supervision in determining the extent of vertical shifting of the type wheel ii. The copending application referred to explains how, in response to the conventional case shift signals, bars 43 or 44, depending upon which of the two signals is received, rotates about a pivot located at its left extremity, Fig. 1, so as to present one or another of the lugs 45 and 46 forwardly. When bar 43 is thus selected and its lug 45 moves forwardly, there follows towards the conclusion of its selection cycle a rightward movement of all of the bars, including 43 and 44, so that lug 45 being the only one in extended position, is made to engage the lowermost extremity 41 of a shifting lever 48 whose opposite end being provided with the open slot 49 and straddling the stud pin SI of case shift plate 52 causes the latter to be moved leftwardly or into the position illustrated in Fig. l. The immediate signiflcance of this movement is its characteristic placement horizontally of the anchor pivot 53, see also Figs. 3 and 4, but a further consequence of this operation will be discussed later.

Alternatively, upon the selection of the other shift bar 44 and the consequent movement of its lug 46 into the path of the lowermost extremity 54 of lever 55, there results the movement of case shift plate 52 rightwardly to an extent of movement as denoted by the elongated hole 58 and the consequent restoration of case shift lever 48 to its assasaa first position, since the two levers 48 and II are articulated to the common pivot shaft 91, each serving to restore the other upon its selection. The result of the operation of lever ll so far as the specific contemplation is concerned is in the movement of said pivot stud 99 rightwardly for a purpose to be discussed later.

Pivot screw 93, which has already been introduced above, constitutes a critical center and pivot support for an important element in the shift mechanism, namely, bell crank i9l--i92, about which more will be said later. Moreover. this key pivot is anchored in a sidewardly extending shelf Hi4, Figs. 3 and 4, which is integral with the shift plate 52 whose progress from side to side is governed by the selectable levers 48 and 44 as just described. When either of its alternative positions is established, shift plate 52 is thereat detained by the action of a spring loaded detent lever 59 which is pivoted to the plate 52 at 69 so as to urge with its V-shaped extremity against one side or the other of a fixed rod 10. When moved to its opposite position from either, lever 59 is cammed about pivot 69 through cooperation of its V-shaped nose and said rod Ill.

Referring now again to the vertical shifting frame 24 which carries with it the type wheel I i, it will be noted that its side wall, Fig. 1, contains an irregular aperture 59 whose lower edge provides two shoulders or steps indicated 59 and BI seen also in Figs. 5 to 8. The movement oi frame 24 is maintained in a parallel vertical direction not alone by the aforedescribed alignment studs 29 but also because of shaft 51, one end of which is rigidly anchored in the framework and the surrounding roller sleeve carried by said shaft fits closely within the confining slot 62 of framework 24. The frame 24 is lifted by means of an integral ear G9 to which is connected a comparatively stout but nevertheless yieldable lift spring 64, having an upper loop which is suspended irom the hooked extremity 69 of a lifting lever 88 pivoted at 91 in a stationary portion of the printer structure.

Lever 66 is of the third class type since the lifting force is applied thereto at an intermediate point in its length by means of a roller 68 which is carried at the end of one arm 59 of a bell crank lever whose other arm II, having an integrally associated bracket 12, carries two rollare 13 and 14. Of these, roller 13 is actuated by the periphery of an initially effective operating cam 15 carried upon the auxiliary shaft 16 while roller 14 is confined within the trackway of a side channel cam 11, the two cams functioning jointly in a manner fully described in said copending application.

Auxiliary shaft 16 and the principal control shaft 18 receive their power from drive worm 36, which is carried by the motor shaft, through a gear train which includes the primary driven gear 19, a driving gear Bl integral therewith and a secondary driven gear 82 carried by shaft 16 and meshing with the just described driving gear 9 I. Cam 151s dependent for rotation upon tooth clutch 83, a positive saw-tooth driving coupling which is brought into driving engagement under the supervision of a trip lever initiated by a cam carried upon the upper end of shaft 19, said cam being part of a driven sleeve described in greater detail in said copendlng application, and dependent for rotation upon the friction clutch comprised of the two discs 94 and 95, the assembly of cams 91 being free to rotate upon the release of stop arm 99. Shaft I9 rotating at all times under the influence of driving worm a, imparts rotation to its associated apparatus only upon the release of friction clutches 94 and I! to impart rotation to the cam assembly 81 and through the teeth of clutch 99 to impart rotation to the aforedescrlbed cam 'll.

Though type wheel shifting frame 24 is lifted to variable extents by arm 69, spring 94 and bell crank 99 as just described, the degree of movement on the part of the lifting levers is always the same. The extentof rise on the part of type wheel II is determined by the position of a pair of stop lugs indicated 99 and 9|, Figs. 1 and 5 to 8, which lugs are capable of being variously arranged so as to engage one or the other of the stop shoulders 59 and BI already described. It will be observed that lug 91 is the lowermost one and also that it is substantially wider than is the upper lug 99. When both lugs 99 and 9| are in the leftward position as indicated in Figs. 1 and 5, then a condition obtains whereat type wheel ll will be permitted to rise only to an extent which will align its upper row of characters if in printing position opposite the platen i4 and printing ribbon 2i.

correspondin ly, when both lugs 99 and 9| are moved into the intermediate position, engagement by shoulder 61 will be had permitting the type wheel ii to rise until its second row of characters I! will be brought into printing position as shown in Fig. 6. When lug 9i is moved to the extreme right so as not to be engageable by either of the shoulders 59 and Bi and when under this condition lug 89 is permitted to assume its left-hand position such as viewed in Fig. '7, then the type wheel ii is permitted to rise until its third row of characters I! is brought into printing alignment. Finally when with lug 9i still at the extreme right and the upper lug 99 is brought into the intermediate position, type wheel I i may be permitted to rise in response to the lifting apparatus until the lower or fourth row of characters I! is brought into printing alignment as shown in Fig. 8.

There will now be reciteda description of the apparatus which, in response to line signals, controls the disposition of the lugs 89 and 9i to effect the four designated case shift conditions which will be referred to for convenience as the first, second, third, and fourth shift positions in an order corresponding to the aforerecited description and also to correspond with Figs. 5, 6, 7, and 8, respectively.

Shift plate 62 is threaded to receive two stud screws 92, the latter being preferably of the shoulder screw type with neck portions of suincient length to be able to receive and support thereat the main body portion 93, Figs. 3 and 4 of lug 89. Also threaded into plate 52 are a pair of shoulder screws 94 whose necks are of sufficient length to support freely the body portion 95 of lug 9| which member includes also an upwardly extending projection 96, Fig. 1. A tensioning spring 91 having one end looped around an anchor post 99 integral with member 95 and its other end loop secured to the anchor post 99 which extends from a stationary part of the machine, tcnds to urge lug 9i and its main body portion 95 toward the left as viewed in Figs. 1 and 5 to 8. This influence is overcome selectively through the instrumentality of bell crank member Nil-I92. One arm I02 of said bell crank engages the aforedescribed upstanding lug 98 of member 95, while its opposite arm is engaged by a lever arm Ill under conditions which will now be described.' Bell crank Ill-III is pivotally supported by screw II which, it will be recalled. is carried by the shift plate 82 and particularly in a horizontally extending platform I" thereof.

A lever it! of which arm III is an integral portion constitutes one of a set of six storage members indicated in Figs. 2, 3. and 4. f the set, however, lover I is the only one having the configuration indicated, the remaining levers I08 being similar to each other but differing in contour as may be noted in Fig. 2. Certain common characteristics of all of the levers I and IE6 include their alternatively selectable positions determined by the engagement of their stop projection Hl'l with one or the other of a pair 'of limit pins Hi8 and lill, and their latch arm lll through which they may be retained in one or the other of their alternative positions by a looking bail H2. When latching or looking bail H2 is withdrawn, as illustrated in Figs. 2 to 4, which is its condition during a brief signal transfer interval, each lever I05 and I" is capable of assuming either one or the other of its alternative positions and, in response to a received code combination signal, a corresponding set of conditions is imparted to the set of levers I05 and M6 by means of a set of positioning swords H3. flat steel members with blunt extremities Ill, and universal connection discs I III. Beyond this point, the selector mechanism generally indicated H4 is the same in structure and operation as that disclosed in the aforementioned copend ing application, save that whereas the distributor cam assembly H5 in the instant apparatus is provided with six setting cams I It, the copending disclosure contemplates but live.

While all of the general class of storage elements HIS are capable of assuming one or another of the alternative conditions in accordance with the conventional operation of printing telegraph apparatus, lever I05 having particular significance to the present invention may also assume a right or a left position in accordance with the setting it receives from its associated sword H3. The illustration in Figs. 3 and 4 show lever I05 in the counterclockwise position; that is, with its lug I01 abutting the right side stop pin I08. The opposite or lefthand position of member I0! is indicated in Fig. 2. With a given setting or presentation of pivot screw 53, it will be understood that the alternative positions of lever arm It! may be made to effect alternative positioning of hell crank it! and through it, in turn, to cause to be shifted through upstanding lug 96 the horizontally shiftable body portion 85 of shift controlling lug 9|.

Accordingly, with lever H35 in its spacing condition, as illustrated in Figs. 3 and 4, bell crank llll is maintained in its clockwise extremity with arm "I! urging against the upstanding lug 96 and maintaining body portion 95 so that lug 9| seeks to achieve its right-hand extreme position, as illustrated in Figs. 7 and 8. This condition prevails so long as selector I05 is in its spacing condition notwithstanding the two possible conditions of shift plate 52. However, when pivot 53 is moved (along with shaft plate 52) toward the left, Fig. 6, projection 9| may then assume an intermedite disposition as shown.

Lug 89 which is carried as an integral member of plate 52 is shiftable together with that plate so that it may assume either one of two alternative conditions as illustrated, for example, in

Figs. 5 and 6. Because, however, elongated slot 50, Fig. l, is of limited extent only, the shifting of plate 82 leftwardly as for the purpose of placing projecting lug B8 to align vertically with shoulder I! will also modify the placement of projection 81 through the engagement of the end of slot 68 with bolt 94 so that there is obtained ultimately a condition such as that illustrated in Fig. 6. But, it is to be understood that plate 52 may exert an influence on the disposition of member only when said plate 82 is moved to its extreme right-hand position and when, under the circumstances, member 85 seeks to attain its extreme left-hand position, As a result of these efforts, plate 52 will be moved to its extreme right-hand position under the influence of selectable element 43, but member will be limited in its effort to achieve its lefthand position because of the restrictive nature of slots 58 which will permit said member to move leftwardly only to an extent where its pro- Jection 9| will assume the condition indicated in Fig. 6.

Recapitulating, selectable elements 43 and 44, acting through the medium of levers I5 and 48, move plate 52 and together with it the projection ll! into either of two alternative conditions, as exemplified in Figs. 5 and 6, Fig. 7 being, so far as projection 89 is concerned, similar to Fig. 5. Selectable element ill! having two alternative conditions and acting through bell crank IBI, spring 81 being a return agency, is enabled to move member 95 and through it pro- Jection ill into either of two alternative conditions, as exemplified by Figs. 7 or 8 on the one hand and Fig. 5 on the other. The intermediate condition of Fig. 6 is attained when plate 52 is in its extreme right-Land position and member 95 seeks to achieve its extreme left-hand position. As a result, member 95 is intercepted in its path of progress because of the restriction by elongated slot 56 and is permitted to move only to an intermediate position, as illustrated in Fig. 6.

It is therefore to be understood that a total of four case shift selections may be achieved in response to (l) the two standard case shift signals conventionally used for elevating a type wheel in the manner described in the copending application referred to above, and (2) an additional or secondary case shift in response to the sixth code impulse which effects corresponding positionment of the storage element I05.

First modification Figs. 9 and 10 illustrate a modified form of signal transmission system for effecting the control of a double character shift supervision (a total of four shift positions) after the manner of the preferred embodiment described generally above. Contrasting with the system already described, this modiflcation contemplates the use of a five-unit line signal code instead of a sixunit code, the secondary shift signal characteristic being inherent in the nature of the polarity of marking impulses instead of the marking or spacing nature of the sixth pulse. It is proposed, accordingly, to make available for signal transmission both positive and negative current potential, either one of which is to be used permutatively with no-current to produce five-unit Baudot permutation code signals, but whether the marking signals are constituted of positive current or of negative current will determine the alternative characteristic of the secondary shift control.

In the diagrammatic representation, Fig. 9. the reference character I2I denotes a transmiting distributor of the rotary type which may be controlled by start-stop or multiplex (synchronous) supervision. A tape sensing unit generally indicated I22, is provided with six tape hole feelers. Five of them are committed to the liveunit signal code, and their contactors I24 are therefore associated with the five segments of the transmitting distributor I21, but a sixth one whose contactor is indicated I23, is designed to sense the presence or absense of a sixth perforation in a six-hole tape, and serves to introduce positive or negative current to the contact segment I34 which, in turn, introduces corresponding current condition to the marking signals, as will now be described.

The tape transmitting apparatus I22 may be of any conventional type, one embodiment being illustrated in U. S. Patent No. 1,661,012, except that instead of providing but live sensing levers and associated electrical contacting apparatus, unit I22 may correspond in all respects thereto so far as the conventional feeler levers I24 are concerned, special feeler I23 being simply an additional member and having an additional pair of contacts with separate contacting points represented by the rectangles I25 and I26. The cable I23 contains five lines, each connecting one of the feeler lever contactors I24 with its asso-- ciated segment in distributor ring I23. A line I3I connects special feeler contactor I23 with one terminal of the winding of a polar relay I32. Continuing from the other terminal of polar relay I32 is a line I33 leading to a special segment I34 of a distributor ring I35 adapted to be bridged by a pair of brushes I36 with the grounded ring I31.

It is to be noted that the aforementioned segment I34 aligns with and corresponds to the distributor cyclic period coincident with the conventional start segment I33 of distributor ring I29 and that this cyclic interval is in advance of the first one of the five permutation code segments of ring I23. For this reason, it will be observed, the operation of relay I32 will occur in advance of the time that brushes I33 encounter said permutation code segments of ring I23. Thus, the transfer operation on the part of relay I32 is made to occur during a no-cur rent interval of the line I43 (segment I38 having no connection with any of the feelers) and there is in this way prevented the possibility of foreshortened or clipped impulses, a result which might not be avoided save through the utilization of a neutral interval during which to exercise the current reversal.

The normal position of tape feelers and their associated contacts I23 and I24 may be supposed in the manner illustrated in Fig. 9; that is, with their contacts engaging terminal blocks I25 and HI. Accordingly, when presented against the surface of the tape, said contacts I23 and I24 seek to engage the contact blocks I25 and I21, those encountering perforations being permitted to do so and accordingly connecting their respective segments of ring I29 with block I21 which, in turn, receives current potential over a line I42, contactor I43 from one or the other of a pair of opposite current sources I44 and I45. Those not encountering such perforations, however, wiil, during the critical portion of the signal transfer, fail to obtain current and hence cause to be conditioned their respective segments of ring I23 without electrical potential or with no-current."

Relay I32 being of the polar type as already mentioned, its armature I42will move to the right or to the left engaging the contact points I46 or I41 in accordance with the nature of current coming over line III from contactor I23 which may engage positive current block I26 or negative current block I25. When placed in either of its positions, armature I43 remains until altered by an opposite polarity introduced into the windings of its relays I32. Accordingly, it wiil be understood that the presence or absence of a sixth perforation will correspondingly impress block I21 with positive or negative current and that on this account, permutation code sig nals generated over the segments of ring I29 may be either positive and no-current or negative and no-current and that they will accordingly be issued out over line I48.

At the receiving station, there is connected to line I43, in series, the selector magnet I43 and a receiving polar relay I5I whose armature I52 will engage or withdraw from its contact point I53, depending upon whether the marking impulses of the received signals are of positive or negative polarity. In accordance with the movements of armature I52, operating current will be introduced to or withheld from the winding of the secondary shift control relay I54, over an obvious circuit, Fig. 9.

A bell crank armature I55 pivoted at I56 and responsive to the energization or nonenergization of relay I54 actuates an intermediate bell crank lever I51, resembling in appearance and operation the bell crank lever- IIII discussed in the preferred embodiment above. The actual relationship and position of bell crank lever I51 is as illustrated in Fig. 10, whereat its vertically extending arm engages a projection I53 integral with the horizontally shiftable bar I53 whose interponent lug IGI corresponds in appearance and operation to the lug 9| of the preferred embodiment.

Bar I53 will be supported in the same manner as bar 95 of the preferred form; that is, by a shiftable plate, such as plate 52, and will be capable of responding in the same manner as the other member. Likewise, a lug I62 corresponding to the described lug 33 will be provided and will also be carried by said shiftable plate, the two lugs I6I and I62 to function under the control of bell crank I51 in a manner and for the purpose already described in the preferred embodiment.

Since the operation of secondary shift control magnet I54 by the current characteristics as aforedescribed need not be established except during any one impulse of a signal, and since the most favorable opportunity for executing the performance (energization or release) of said magnet I54 is coincident with the stop (R) impulse interval, means have been provided for shunting the supervisory polar relay I5I so that it may not fluctuate except during the precise interval coincident with the stop signal impulse, This supervision is exercised by a special cam carried upon the distributor shaft I which, acting through a follower lever, causes the contact pair I50 to come ajar during the distributive interval coincident with the stop impulse, thereby removing the shunt ground from a local circuit as shown in Fig. 9 cutting into circuit relay I5I together with magnet I49 and permitting both members to respond to the stop impulse. At all other times in the distributive cycle, however, the apex of said cam of the distributor shaft I88 is withdrawn from the follower lever permitting contact pair I58 to engage and to thereby effectively shunt relay Iil out of the signal responsive circuit.

It is to be understood, therefore, that the modified showing of Figs. 9 and 10, illustrates another manner of controlling the functioning of a secondary shift control structure but, in this case, under the supervision of a. five-unit code instead of a six-unit code as contemplated in the first described system. A shift characteristic for the purpose of supervising a secondary type wheel shift function has been embodied into the standard five-unit code by alternating the current characteristic of the marking impulses between plus and minus, the spacing impulses being in all cases no current.

Second modification In Figs. 11 and 12, there is illustrated a further system of printer control and line transmission for utilizing the five-unit Baudot code signal in such a manner that it will afford sixunit signaling possibilities. Other manners of accomplishing this result have already been disclosed in connection with the embodiments described above, as by providing means for supplying two current conditions for the marking impulses.

In the manner of signaling contemplated in connection with the present embodiment, there is employed a five-unit Baudot type code combination signal having, in addition to the conventional five selective impulses, a special impulse utilized for supervising secondary shift control and a start impulse interval of a polarity opposite to that of its preceding or special impulse interval, under the specific contemplation of the five code combination impulse interval.

In other words, whereas conventional five-unit permutation code signals being. provided with seven componential impulse intervals contemplate start and stop impulses of predetermined and invariable line characteristics, means are herewith provided for varying the characteristic of the stop signal interval so that it may have utility for selection as well as phasing supervision and for making the start initiating apparatus responsive to a start impulse condition of electrical polarity opposite to that of the immediately preceding stop impulse interval which, as has been said, may consist of either one of two alternative line conditions.

In the incorporation of this plan of operation, it has been found expedient to utilize plus and minus current conditions to represent marking and spacing instead of the conventional practice of utilizing current and no current conditions for this purpose. Moreover, as in the case of the first modification, Figs. 9 and 10, there will be utilized for the purpose of signal translation a six feeler sensing apparatus generally indicated by the reference character III. Reader mechanism III is illustrated as having seven contactors I12 to I18; however, contactors I11 and I18 both are carried upon a single feeler lever while each of the remaining contactors I12 to I18, inclusive, is carried individually upon a feeler lever.

In accordance with the operation of its feeler lever, each contactor is spring urged so that it will engage the contact block towards the right up of seven segments.

and is capable of movement in an opposite direction so as to engage the contact block towards the left, as illustrated in Fig. 12. The contact block at the right is comprised of a large section indicated I18 and a smaller section insulated therefrom indicated II. The contact block at the left is similarly comprised of two sections, the larger one indicated I82 and the smaller one I88. Moreover, as may be noted the small contact block I88 is connected electrically over an obvious line with the large contact block I18 and correspondingly small contact block I8I is connected electrically with the large contact block I82. Opposite sources of grounded potential indicated I88 and I88 are connected respectively to the contact blocks I83 and III over lines I88 and I8'I to the oppositely placed contact points of armature I88 under the control of a polar relay I88.

The winding of said relay I88 is connected at one end to the aforedescribed feeler contactor I11 and at its other end to a distributor segment I8I situated in distributor ring I82. This distributor I86 which includes also distributor rings I88, I94, and I85 is of the start-stop type having a brush carrier I!" which supports two pairs of bridging wipers I88 and I88. Brush carrier I8'I of transmitting distributor I88 is conventionally illustrated in Fig. 12, but it is to be understood that this element is driven through a friction coupling preferably in a rotary direction and that it may be restrained from movement by the intervention of an armature 2M under the supervision of start magnet 282. Also, that the pair of wipers I88 serve to connect segmented distributor ring I88 with the solid distributor ring I88 which is electrically connected to line 283, and that the pair of wipers I88 correspondingly connect distributor ring I82 which contains the segment I8I aforedescribed with the grounded distributor ring I85.

Attention will now be given to distributor ring I83 which, as may be observed In Fig. 12, is made When the brush carrier I86 is in its arrested position, wiper I98 is contacting the slightly longer segment designated 5 In the distributor ring I83. Also, it may be observed that following the segment 5 which serves also in the capacity of a stop segment as will later be described, there is encountered a start segment designated by the character S.

Following this segment is one designated 0 (zero), which has been arbitrarily assigned to the function of supervising the secondary shift. This control is otherwise executed, in accordance with the present embodiment, in a manner generally similar to that described above in connection with the preferred embodiment.

The remaining segments 1, 2, 3, etc., including segment 5, which as has already been stated, functions in a dual capacity, serve to distribute those signal impulses which relate to the composition of the permutation code. Segment 5 is connected over a line 284 to the armature I88 of polar relay I88. Segment S is connected over a line 285 with the contactor I18. Fig. 12 illustrates diagrammatically transmitting station equipment including a perforated tape controlled mechanism and a rotary signal transmitter under the supervision thereof for issuing signals of a type adapted to exercise the control function including primary and secondary shift supervision for printing apparatus having mechanically the characteristics exemplified in the showing of Fig. 11.

As the brush carrier I91 proceeds in the downward directionas indicated by the arrow 299, the pair of wipers I99 leave segment No. and encounter segment 5 bridging this element of distributor ring I99 with the solid line ring I94. Assuming, for the sake of illustration, that the perforated tape signal which has just been positioned and which has been impressed upon the feeler levers of. record reader "I is such that contactors I11'and I19 (which operate in unison) are moved to the right, that is to say, with contactor I11 engaging block I19 and contactor I19 engaging block I9l, distributor segment No. 5 will have received positive current potential from grounded battery iii if relay I99, in accordance with its preceding operation, has been left in a position whereat its armature I99 engaged the contactor of line I 99. This circuit is traceable from positive battery I94, line I99, armature I99, line 294, segment No. 5 of distributor ring I99, brushes I99 to outgoing line ring I94 which is grounded at the receiving station. As the brushes proceed to the next segment which is designated S, opposite polarity is issued over line 293 connected to ring I94 over the following circuit. Beginning at grounded battery I95, negative battery is available at block I9I, contactor I19, line 295, segment 8 of ring I99, brushes I99 to line ring I94.

If instead of the supposed example described above, the particular signal had been one in which the feeler lever with which contactors I11 and I19 are integrally associated was positioned to the left causing engagement with contact block I92 and I99 instead of contact block I19 and I9I, the electrical characteristics relative to segments 5 and S would be opposite to that just described. With the brushes I99 passing over segment 5 and bias polar relay I99 energized in its opposite condition with its contactor armature I99 engaging the contact of line I91, negative current would be available to segment 5 from negative battery I95, line I91, armature I99, line 294, segment No. 5 ofring I99, brushes I99 to outgoing line ring I99. Each of the feeler contactors I12 to I19, inclusive, is connected over an individual line wire with an associated segment 0 (zero) to 4 of the transmitting distributor ring I99. Accordingly, when a feeler lever encounters a perforated position in the tape, its contactor will be moved into one position, say the right-hand one, engaging the contact block I19 while its said feeler lever encounters a nonperforated position and its contactor will assume an opposite condition; that is, contacting the opposite block I92. The designation of plus or minus signals to correspond with perforated or nonperforated signal components is arbitrary, and it is to be understood that the reverse association is equally feasible.

The foregoing is true not only of the conventional five feeler levers of contactors I12 to I19, but also of the special feeler lever with which are associated two contactors I11 and I19, as has already been mentioned. One significant difference, however, does prevail which will now be noted. In the case of the special or sixth feeler lever, when a perforation is encountered and, say both contactors are moved to the right, contactor I11 will be introducing positive current from battery source I94 to the winding of bias polar relay I99 while contactor I19 will be introducing negative battery from source I95 over line 295 to the start segment 8. Conversely, with the contactors I11 and I19 in the opposite position, that is, engaging contacts blocks I92 and Ill, negative current originating from source 199 will be introduced through contactor ill to the winding of bias polar relay I99, while positive current originating from source I99 will be introduced over line 299 to start segment S. Accordingly, since armature I99 of relay I99 is connected to the fifth segment 5 which, as has been said, serves also as a stop interval segment, the result of the operation of the sixth or special feeler lever will be understood as one controlling the reversal of potential for start segment S, that is to say, with a given condition on the part of segment 5 which may be either plus or minus the sixth feeler lever controlling contactors I11 and I19 operate to provide an opposite current potential to the start segment S.

The purpose in having provided bias relay I99 with its armature I 99 connecting plus or minus current to the segment 5 instead of directly connecting the contactor I11 to said segment 5 is one of permitting the fifth impulse signal interval to be stored in advance of the time that the distributor brush I99 encounters its segment 5 so that eventually when said brush I99 does so encounter said segment 5, the entire time interval may be utilized to permit the transfer and operation of the feeler levers from one signal to the next with the phasing value (see Fig. 13) of sig nal interval 5 already safely stored by reason of the response of armature I99 of relay I99. Accordingly, the segment I9I of ring I92 is located well in advance of the cyclic interval at which segment No. 5 occurs in ring I99 obtaining thereby an adequate margin of line time for the purpose just described.

In Fig. 12, the reference character 299 designates a receiving station and within said outline are contained the symbols representing vital apparatus responsive to the signals generated by the transmitting distributor I99. 01' these, the reference character 291 denotes a bias polar relay whose armature 299 is grounded, and is adapted to reciprocate between two contact points 299 and 2 which are part of a local circuit for supervising the operation of principal control magnets 2l 2, see also Fig. 11.

Also situated in said receiving station local circuit are a pair of contactors indicated 2l3 and 2. The former reciprocates between a pair of contact points 219 and M9 and the latter between a pair of contact points H9 and 2I9. In the printer apparatus which is shown in mechanical detail in Fig. 11, contactor 2H and its associated contact points 2I5 and 2I9 are indicated as an assembly controlled by a follower arm 22I pivoted at 222 and supervised by a cam apex 229 which is one of an assembly carried upon the distributor cam shaft 19, see also Fig. 1. Also carried on shaft 19 as an integral part of the aforementioned cam assembly and in addition to the aforedescribed cam having the apex 229 are five selector signal cams whose apices actuate the five bell crank levers 22! mounted in pivotal alignment upon shaft 222 and hence af- Iording visibility only to the foremost ones in Fig. 11.

A sixth cam similar to said iive distributor cams is utilized for the purpose of actuating the storage lever I99 which is similar to the one described in connection with the preiererd embodiment above and which actuates in a similar manner a bell crank "I for the purp e Obtaining the referred to secondary shift control. In addition to the cams already designated in the assembly carried by shaft 10 is one indicated 226, having a plurality of spaced spices, which when said cam assembly is rotating, serve to rock the armature bell crank 22! about its pivot 223 for the purpose of presenting its magnetically attractive arm 223 against the polar face of magnet 2|2. This operation or cam 223 in assisting the armature 22'! and thereby diminishing the work of magnet 2!2 is in accordance with recognized practice in printing telegraphy.

As illustrated in Fig. 11. storage lever I! is disposed below the other storage levers 23! and 232. This arrangement is in a general sense arbitrary for the shift signal impulse, in the particular instance corresponding to the segment 0 on the distributor ring !33, Fig. 12, may be located if preferred in any other position with respect to the componential sequence both in the distributor ring I33 as well as in the stack of selector storage levers, Fig. 11, designated !03, 23!, and 232. Storage levers 232 are live in number corresponding to the signal components which utilize the segments 1, 2, 3, 4, and in the transmitting distributor ring !83. Storage lever 23!, together with the top one oi levers 232, correspond to the code signal impulse occupied by the segment 5, and in the order designated each impulse ultimately serves to place its associated lever 23! or 232 in one or another 01' its two possible positions as already described in connection with the preferred embodiment.

For the purpose of understanding the principles of the instant improvement, it will suflice to state that ultimately the storage signal is manifest by a conditioning of the several storage levers I05, 23!, and 232 with the lever l05 exercising the function of controlling secondary case shift bell crank I0! and levers 232 functioning to condition the set of code discs 234 which are five in number.

Storage lever 23! controls the shifting of abovementioned contactor 2!3. Accordingly, when it is found in the position as illustrated in Fig. 11, it permits contactor 2I3 to engage its upper contact 2l0, and when it is in an opposite condition such as that occupied by the counterclockwise extreme storage lever 232, in Fig. 11, said lever 23! by its protuberance 235 will engage the insulated extremity of contactor 2!3 and thrust the latter member so that it will disengage contact 2 l 3 and engage contact 2 I 3 instead.

A supervision of contactor 2 is had by follower lever arm 22! under the control of cam apex 223, that is, when apex 223 is in the position indicated, contactor 2I4 is thrust against its left contact 2li but at all other times, that is, when apex 223 is clear of the follower arm 22!, contactor 2 is permitted through its own spring tension to recede from contact point 2ii and to engage instead contact point 2!6. There will now be described the effect of the supervision of contactors 2!3 and 2 by the above-described apparatus.

Let it be assumed for the sake of illustration that a particular code signal transmitted over distributor I90 is comprised of a certain combination of code impulses whose fifth component (three being a total of six components including 0) is constituted of marking characteristics, that is, the current characteristic which will position its sword 233 in the manner indicated in Fig. 11 so as to place storage lever 23! in the position indicated in this illustration. Accordingly, contactor 2l3 will b permitted to recede from contact point 2 (assuming that a preceding signal differed in respect to this signal component) and to engage instead its co tact 2!3. This will correspond also to the placement of contactor 2", as illustrated in Fig. 12. In order to produce this result, the nature of the signal impulse will be such as to effect the polar relay 20'! to cause it to move its armature 203 to engage contact point 209 so as to open the circuit forselector magnet 2!2 and to cause the armature 238, Fig. 11, to assume its marking position. Subsequently, there will follow the start signal impulse whose effect upon relay 20! will be opposite to that just described in connection with the No, 5 signal impulse, which reversal is assured by the apparatus of the transmitting distributor described above. In consequence, relay armature 203 will be moved counterclockwise to engage its contact point 2!!, as illustrated in Fig. 12 closing the circuit for energizing selector magnet 2!2 and thereby releasing the selector apparatus for a given cycle.

Under the alternative condition of operation, that is, with the No. 5 impulse being of spacing nature. contactor 2i3 will be withdrawn from contact point 2!! and thrust into engagement with contact point 2!3 instead. As described in said copending application, referred to above, cam shaft 18 carries in addition to the aforedescribed operating cams 223 and 226, a spiral distribution of cam apices indicated 230, five in number. Each one of these is related to one of the signal impulses l to 5, inclusive, whose corresponding segments appear in the distributor ring I93, Fig. 12, while the final one of said series specially designated 230A, Fig. 11, is, in accordance with the present embodiment, of double width.

This is so because unlike the other of the cams 230 which serve to actuate but a single one of the claw levers 224, it alone actuates a pair of said claw levers 224. Since said levers 224 are all of the same contour, they may not be differentiated in the showing of Fig. 11, however, on account of the spiral arrangement of said cams 230, each claw lever 224 will be operated at a particular cyclic interval, except said two claw levers 224 which are operated in unison by the special apex 230A. Each claw lever is provided with a sword 233 but the sword which is associated with the anterior lever 224, as viewed in Fig. 11, has been specially designated 233. Each sword 233 and 233 terminates with a blunt point projection which rests against one side or the other of a hump 238 of an intermediate lever element, five of which are designated 232 but the one related to the sword 233' of which is designated 23!. The five similar levers 232 each are provided with a tail piece 233 that serves as a locking projection by being placed on one side or the other of a look-- ing ball 24!, which member assumes the position indicated in Fig. 11, except during a brief interval following the conclusion of a particular signal when its lever arm 242 is released by the operation of the aforedescribed auxiliary shaft 13.

Accordingly, while the several swords 233 and 233' may assume one position or the other as its abutment 243 or 244 encounters the downwardly extending vane 245 or 243 of armature 230, levers 23! and 232 may not be correspondingly positioned until said swords 233 and 233' are thrust downwardly by the clockwise movement of the claw levers 224, which movement is urged by their individual springs 141 as well as by auxiiiu'y individual springs carried upon an integral extension of lever arm I.

The auxiliary springs of lever arm I are not shown in Fig. 11 of the accompanying drawings, but reference may be had to the aforedescribed copendlng application where it is explained that their function is of an auxiliary nature and to assist the principal actuating springs 2". None of the springs 241 or the auxiliary springs mentioned may actuate their associated claw levers 224 during the time that the locking bail I intervenes by blocking the extending portions if! of levers 232. However, since lever ill is not provided with an extension 2 as are the remaining ones of the levers designated 232, its response to its associated sword 233 will occur immediately following the instant when cam apex 280A passes the follower projection of claw lever 22 which carries said sword m.

Thus, while the consummation of a signal transfer relating to a particular set of code impulses of any signal must await a brief interval following the fifth or stop code impulse, the actuation of contactor III by the projection 23! of special storage lever Ill follows immediately upon receipt of the fifth code impulse. This assures the operation of selector magnet fl! for the purpose of arresting the rotation of shaft l8 coincidentally with the signal interval corresponding to the stop or fifth code combination impulse, even though the other purpose of the particular impulse, namely, that of setting one of the code discs 284, may await its regular period of operation which, as has been said, occurs after the lapse of a brief time interval and. in fact, during the occurrence of a succeeding code combination signal.

Cam apex 223 is specially provided for the purpose of actuating the aforedescrib'ed arm III which. in turn, controls contactor Ill. Cam apex 223 is effective to thrust contactor Ill against its contact point ill for a period commensurate approximately with the beginning of the stop or No. 5 code combination impulse and continuin through the start impulse B and into the (zero) or shift controlling impulse. At other times contactor 2H, see also Fig. 12, engages its contact point 2|! for a purpose which will now be described.

Operction of the second modification Concisely stated. armature 2B! of relay Ill fluctuates in accordance with each slBnal impulse, contactor 2 being controlled by cam apex 223 rests against contact point ill at all times except during the stop and start signal interval. and contactor Ill being controlled by the No. 5 or stop signal is moved into one or the other of two alternative positions as a result of the operation of the transfer mechanism, described above, only during the period corresponding to this impulse. Under an assumed set of conditions, in response to marking signals, both armatures Ill! and 2 it will be deflected downwardly, that is, to engage their contact points ill and fit, while under spacing signal impulses, said armatures will be in their opposite position. that is, engaging respectively their contact points fill and 2. Also. it is to be recalled that since the No. 5 impulse functions in a dual capacity of effecting the distributor stop control as well as of entering into the permutation code, each cycle must be considered as including a part of the preceding No. 5 impulse. which affects the current characteristic of the start impulse as well as of the concluding No. 5 impulse. because it, together with the impulses No. 1. 2. 8. and 4, comprises the code combination of the particular signal.

Accordingly. when the No. 5 impulse of aweceding signal happens to be marking, armature "I will be thrust into engagement with its contact point Ill. contactor m will be thrust into engagement with its contact point III (on account of the operation of cam III). and contactor Iii, as a result of the transfer operation. will be moved into engagement with its contact point ill. This will complete a circuit traceable from grounded battery at II I, winding of magnet ill. line I". contactor Ill. and its contact point 2 I! with which it is then in engagement, line Ill, contact point II I, and its armature ill which is then in engagement with it to ground. As a result of the continued energization of magnet ill, its armature is held and the rotation of shaft ll is arrested in accordance with the conventional operation of printing telegraph selector shafts. This condition continues until the circuit for energizing III is broken, which change occurs upon the receipt of a proper start impulse over segment 8 of transmitting distributor ring ill. The polarity of the start signal being opposite to that of the No. 5 or stop signal impulse. as already explained, causes armature "I to be moved to engage its contact point Ill! and away from its contact point fll. This interrupts or opens the circuit for magnet III, causing the release of its armature 238 and consequently initiating the rotation of receiving distributor shaft is in a manner clearly described in the copending application referred to.

As distributor shaft 18 rotates, cam apex 22f rides 08 the projection of-arm Ill permitting contactor lid to be drawn away from its contact point lit and to come into engagement instead with its contact point fit, meanwhile contactor Ilf remaining in engagement with its contact point If! because it can be changed only during the occurrence of the fifth impulse. As a result of the change in contactor 2 from contact point lit to contact point Ill, no effect is obtained at this time. magnet III continuing to be deenergised until during the course of the succeeding six signal impulses, 0, l, 2, 3, etc., armature 20! in response to its relay Ill returns to engage its contact point II I, which response can occur only under the control of marking signal impulses.

In the event that a. marking impulse is received during the 0 (zero) impulse interval, the action of one of the swords 2 upon the storage lever It! will cause bell crank llll to be rotated clockwise in a manner and for the purpose already described in connection with the preferred embodiment above. In the event marking impulses are received for any of the other impulse intervals 1 to 5, inclusive, their storage levers til and I will be accordingly positioned, causing corresponding placement of the several code selector discs ill after the selection has been completed and the transfer mechanism operated, but of particular significance in this connection will be the current characteristic of the No. 5 signal impulse.

If this signal impulse is again marking in nature. the succeeding operation will be the same as the one Just described .xcept for the variations which may occur in the code combination. but if instead the signal impulse corresponding to the No. 5 interval happens to be of spacing nature,

then armature ill will respond by m g its upper contact point Ill and sword Ill will be disposed in the manner illustrated in Fig. 11. As a result of the latter incident, contactor ill will be permitted to engage its upper contact point Ill instead of the lower contact point ill, while on account oi cam apex Ill, contactor Ill will again be thrust against contact point Ill. Thus, a circuit will be completed for energizing the magnet ll! traceable from grounded battery through the windiui of magnet lll. line Ill. contactor lit which is then in engagement with its contact point Ill, line Ill. contactor Ill and its contact point Ill, line ill, contact point Ill and its contactor m which is then in engagement with it. to ground.

As a result, magnet ll! is held energized which is the proper condition corresponding to a stop impulse until an opp c te current condition is received by relay lll causing its armature ill to be withdrawn from contact Point ill and to engage instead contact point ll l. When this occurs, contactor Ill is still held in engagement with its contact point lll because oi the described mnction oi earn 223. which maintains said condition until after the interval corresponding to the start, 8, impulse. Meanwhile, the last described movement oi armature Ill causes the energizing circuit for magnet III to be broken and accordingly releasing its armature Ill for the purpose of initiating rotation 01 receiving distributor shai't ll, as aioredescrlbed.

Thereafter and coincident with the (zero) signal interval, apex of cam Ill restores contactor Ill to its condition prevalent during the major portion of the cycle: that is. engaeing its contact point Ill. When this occurs, that is, when armature Ill of relay :01 eng es contact point 2, marking impulses are thereafter interpreted as magnet Ill energizing impulses, because contactor I l l continues in engagement with its contact point Ill, causing the magnet Ill energizing circuit to be completed over the following described course. The current originates with groimdedbattery Ill through the winding of magnet ill, line 252. contactor Ill. and its contact point Ill, line Ill, contactor ill and its contact point Ill, line Ill. contact Ill and its contactor Ill, to ground. 'I'hus, phasing oi the receiving magnet III as well as of its controlled shaft is is regulated notwithstanding the reversed condition oi the No. 5 and start impulses.

While the foregoing description has been explained and described with reference to speciilc embodiments. it is not intended to be restricted in any manner to the language of the detailed specification nor to the illustrations in the accompanying drawings, except as indicated in the hereunto appended claims.

What is claimed is:

1. A control mechanism for type wheel printing machines having four printing positions, comprising a spring yieldable type wheel lifting means, a frame supporting said type wheel having two abutments, a pair oi shiitable abutment lugs each movable into ali nment with one or the other or said abutments, means under the control oi apair or codecombinatlon signals i'or supervising the movement of one oi said shiitable abutment lugs, and means under the control or a signal condition collateral to said code combination ior supervising the disposition of the other one oi said abutment lugs.

2. In a receiving station printer apparatus, a selector magnet responsive to current impulses Ill) assess:

for releasing to rotation a receiving distributor mechanism and tor conditioning a selector apparatus. a receiving line relay having an armature responsive to alternative line current conditions. two electrical circuits connecting said line relay armature with said selector magnet, a principal witch responsive to the iinal impulse of a series or impulses comprising a signal for preparing one of said two alternative circuit paths to said magnet, and a shunting switch eilective during certain other signal intervals only of a serie for so preparing the other of said paths.

3. In a receiving selector mechanism for telegraph printers, a selector mechanism control magnet, a line relay having an armature responsive alternatively in accordance with received signal impulses, a pair of electrical circuits communicable with said line relay armature for establishing connection with said receiving magnet, a contactor responsive to a predetermined signal impulse translated to said magnet for selecting one of said two circuits and for conditloning it in contemplation of a succeeding signal, and means effective during an initial period of each signal for shunting both said circuits to make either eflective to the performance 0! said line relay armature.

4. A mechanism for eil'ecting supervision of four case shift conditions comprising, a first case shift regulating member responsive alternatively in accordance with a pair or code combination signals, a second regulating member responsive alternatively to a pair or single impulse conditions, and means for yieldably moving a shiftable case member to encounter one or the other of said regulating members.

5. In a receiving station apparatus, a selector magnet responsive to current impulses for releasing for rotation a receiving distributor mechanism and for conditioning a selector apparatus, a receiving line relay responsive alternatively to varying line potentials, two electrical circuits connecting a local current supply through said line relay with said selector magnet. a switch responsive to the final impulse of a series 0! varying line potential impulses comprising a signal for preparing one oi said two circuits to said magnet, and a shunting switch eilective during certain signal intervals only of a series for rendering said line relay communicative with either 01' said circuits.

8. In a printing telegraph apparatus. a selector mechanism, a single magnet for initiating said selector mechanism and for variably operating it in accordance with alternative line current interval variations. means responsive to certain current interval variations for energizing said magnet andto other current interval variations tor deenergiaing said magnet, and means eiIective during certain impulse intervals of a series only for energizing said magnet in response to either current variations and for deenergising said magnet in response to succeeding opposite current variations.

'1. In a system of line signaling, a transmitter station apparatus including a perforated tape control mechanmm, an impulse distributor havinganelementioreachoi'aseriesofimpulses relating to a signal means responsive to said tape control mechanism to vary the electrical characteristics of marking impulse elements or said distributor, and means for eiIectnating said v rying means during a spacing impulse interval of each signal.

8.In astart-stoptransmissicnsystem,are-

ceiving station apparatus comprising a rotary selector shaft, frictional driving means for imparting rotation to said shaft, selective means for controlling said shaft effective invariably during a predetermined impulse of a code combination signal and independent of the electrical characteristic of said impulse, control means for disabling said selective means during a succeeding code combination impulse of electrical characteristic opposite to the electrical characteristic of said predetermined impulses, means for supervising a case shift control under the supervision of one code combination impulse and means for supervising a case shift control under the control of a plurality of said code combination impulses including said predetermined impulse.

9. In a start-stop printing telegraph system, a type shaft, a rotary selector shaft for controlling the position of said type shaft, frictional driving means for rotating said selector shaft, selective means for arresting said selector shaft eflective invariably during a predetermined impulse of each code combination signal and independent of the electrical characteristic of said impulse, control means for disabling said selective means and thereby starting said selector shaft during a succeeding code combination impulse of electrical characteristic opposite to the electrical characteristic of said predetermined impulse, means for supervising a case shift control of said type shaft under the supervision of one of said code combination impulses and means for effecting a case shift control of said type shaft under the supervision of a plurality of said code combination impulses including said predetermined impulse.

10. In a telegraph system, a printing mechanism comprising a type unit capable of assuming four case positions, a selector mechanism responsive permutatively to the impulses of a code combination for controlling the positioning of said type unit among two of its said four case positions, a selector mechanism responsive to the alternative variations of one of the impulses of a code combination signal for determining the positioning of said type unit among the other two of its said four case positions, and yieldable means for moving said type unit to a case position in accordance with the operation of said two selector mechanisms.

11. In a telegraph transmission system, a type unit capable of assuming four case positions, spring urged means tending to move said unit from a normal position to an extreme one of its said four case positions, and a pair of interponent means for intercepting the movement of said type unit under the control of a code combination signal and also under the control of a characteristic impulse of each code combination signal.

12. In a printing telegraph apparatus, a shiftable case controlling unit, spring intervening means for urging said unit from a normal to an extreme one of a plurality of successive case positions, and interponent means responsive to two different selecting characteristics compositely for varying the extent of movement of said type unit by said spring means.

LOUIS M. POTTS.

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