US2466471A

US2466471A - Telegraphic receiving apparatus

Info

Publication number: US2466471A
Application number: US599616A
Authority: US
Inventors: Olsen Leif Christian
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-06-16
Filing date: 1945-06-15
Publication date: 1949-04-05
Anticipated expiration: 1966-04-05

Description

' 1949- c. OLSEN 2,466,471

TELEGRAPHIC RECEIVING APPARATUS Filed June 15, 1945 l5 Sheets-Sheet 5 FAQ: /6

A TTORNE Y Patented Apr. 5, 1949 Leif Christian Q1sen,iN ewcastle-on-=Tyne;.England ApplicationzJune n1 5,1945,.Seria-l 599,616-

n or rpnt in June 16, "1944 .13 claims. .1

The presentinvention has ref erenceto improvements in and relating to telegraphic receivinglapparatus "or instruments either :of the direct .mrint in-g type or of the type which perforatesiholes in a paper tape in accordance with received signals in the Wheatstone (Morse) system of signalling; and it has for its'primary object the full utilisation of advantages which are inherent in :this system of signalling but which have n'ot hitherto heen employed in instruments of the above types;

It is a characteristicfeature of the Morse =code that the elements of this code, viz. dots, dashes,

letter spaces and word spaces are uneven multiples of the shortest signaL'the dot: this loeing onezuriit long a dash and ailetter'space are each-three units long, and a word space is either fi've or seven units long. the elements inany-combination forming achar acter are each one unit long.

If the moments at which-changes f-rom:spacing to marking, or from marking to spacing, may occur are denoted by numerals I '2', 3, et'c., changes from spacing to markingc'an, for instanceg only take place for per-fect'-signals at moments e noted by uneven numerals and changes 'from marking to spacing can then only'takelplace l at moments denoted by even numerals.

According to the "present invention sign-ails which would efiectchanges out of perfect iWl'xe'at stone timing are notrecord'ed by the provision in the instrument of means adapted alternately:

to confine the instrumenttame-acceptance of (a) changes from marking to spacing only za'nd (11-) changes from spacing to markingronly, the.

periods during which "the instrument .isable to accept the changes (a) being substantially equal to'the periods during whichatheiinstrnmentisable to accept the changes ('b').

The invention also comprises the provision'in.

a telegraph receiving, instrument rota-selective means associated withythe signalling relay ofr the instrument onthe one hand and with-the marking and spacing elements of-the.-instr ument ,on the other hand in such a. manner as alternately to select the marking elements and theyspacing during their respectivemeriods, nee-emanate In addition the spaces between.

pendent act the operating mechanismhr instance a *powenrelayand cannnt again 'be 'retracted'Jbyareversal of the saidmec'hanism. In this waycit isilpossib le to 11131112613 polarized-l power relay actuated" byipermanent currents.

=A perforating unit and modifications :thereof according to the present" invention for incorporating in a receiver w il lnow be described with reference to the accompanying drawings wherein "Fig l is' a plan view of the said unit; 1

- Fig.'2 -is'a 'plan-view' thereof-but with the marking-selector and marking elements with-Which-the selector co-operatesremovedf Fig. 3 isga sectional end elevation on theline I i-111mg. 1: I

l' ig. 4 is a. development of the cam used in the unit;

Fig.5 is a detail (in end elevation) showing the signal relay and part of means controlled, thereby adaptedlto. cause the, marking and "spacing selectors alternatelytoassume the co-operativelconditiori,relativelytotheir respective elements and Fig.16'is asideelevation of the parts shown in Fig. 5 except themajor. portion of ,the relay, the parts 'inFi'g s., 5' andjdheing in position "to bringll about .the recording of a; marking signal;

.Eigsflfand ,8.a1j:e ffront and .side elevations, :respectively, of the said parts at the momentimm'ec liatel'y following. the reception of .a marking,

signal change; v .Eigs.,9, and '1 0..are front. and side elevations, respectively, of the said parts after the signal change has. 'been acceptedj' ,Fig-.-l1jis .a deLtail,.-in .plan,,showing more particr ul'a'rly the marking selection in coeoperative position=rvit,h, respect,tothe marking elementsof the instrument;

'LEig. l2.is -a,.detail, showingla mQdification of the- .unit according to. Figs. ,1, f2 and '3;.'th'e view being in plan and partly in section on the' line XII-XII, Fig. 13 which Fijg'.'1 3lis a sectional end elevation of; the modifiedfunitj shown inFig. T2 the section being on "Figs, 14 and =15 are details in end elevation and side" elevation; respectively, of part of another modification of-theun'it;

Fig. 16 is a face viewef a latch-and its. mounting for'co-operation with the integers shown inFigs.

14-and 15gthe llatch' being comprisedpin blocking means operative ion theiselectors, which are-monk fied as shown injfiigskl'lgand 113, said, selectors beingrs'howmadiacent toithezsaidilatchand I .Fig'fi-Tbeing azplan view and Fig. 18 an under-plan view, in section on the line XVIII-XVIII, Fig. 16.

The unit shown in Figs. 1, 2 and 3 comprises a base I from the ends of which supporting

plates

2 and 3 upstand, from the front of which a supporting plate 4 upstands and also from which

columns

5 and 6 upstand.

The plate 2 supports the marking punch l, the spacing punch 8 and the plate 9 containing the tape guide and punch holes, in substantially known manner. The plate 3 carries a bearing H) for one end of the shaft H of a cam I2; the column 6 supports the other end of the shaft. The cam has a punching groove l3 and a selector groove l4; it also has two other grooves for the tape feed mechanism but as this mechanism is not particularly concerned with the invention these two grooves and the said mechanism have been omitted.

The column 5 supports the pivot |5 of punch levers l6 (marking) and I1 (spacing) and the pivot |8 of cranked lever l3 (concerned with marking) and cranked lever (concerned with spacing), said levers l5 and I1 having rollers 2| and 22, respectively, which work in the groove l3 and said levers l9 and 20 having

rollers

23 and 24, respectively, whichwork in the groove I4. The parts of the levers |5, I9, 20 adjacent to the said pivots lie in a slot 25 in the column 5; a cover plate 26 (Fig. 3) secured to the top of the column by screws holds the levers in place on their pivots. Rollers 2| and 23 are above the axis of the cam and the

rollers

22 and 24 are beneath it; the axes of the rollers and the cam axis are in the same vertical plane. the rollers 2| and 22 are 180 apart in their cam groove and the

rollers

23, 24 are 180 apart in their cam groove.

Levers l5 and I! are connected to punch hammers 21 (marking) and 28 (spacing), one above the other, by push rods 29. The lower hammer is slidably borne by a set screw 30 upstanding from the base and the upper hammer is slidably borne by the lower one. The hammers are transversely slotted at 3|, each slot being between the ends of its hammer, and the top of that end of each hammer furthest from its rod 29 is slotted longitudinally at 32. The slots 32 receive the adjacent ends of the punches. The latter are slotted in their undersides at 33 and the disposition of the punches and hammers is such that the claws 34 formed on the ends of the punches by the slotting (33) are engaged by the adjacent; ends of the slots 3|. Moreover the slots 33 in the punches are of such length, and the slots 3| in the hammers are of such dimension in the direction of the axes of the punches, that the hammers can reciprocate under the influence of the cam groove l3 without driving the punches, i. e., the hammer movements can be lost with respect to the punches.

The said hammer movements can, however, be made sensible on the punches, as will be more fully described hereinafter, by a selector 35 (for marking) and a selector 36 (for spacing). The selectors lie substantially at right angles to the hammers. They have

heads

35 and 36 respectively; which normally lie just within the slots 3| and, therefore, are supported at these ends, and have

tail portions

35 and 36 which are slidably borne in

slots

31 and 38, respectively in one edge of the plate 4 (see Figs. 5 to 11). A keeper 39 is secured to this edge of the plate by screws. (The keeper is omitted from Figs. 6, 8,

Therefore,

10). A blade spring 40 secured at one end to the plate 4 tends to urge the head 35' fully into the slot 3| of the marking hammer and a like spring 4| tends to urge the head 36 fully into the slot 3| of the spacing hammer. When the heads are fully in the slots they lie between the punches and the opposite side of the slot and, therefore, communicate the forward or punching strokes of the hammers to the punches. Return strokes of the punches are effected by the springs 42 around the latter (Fig. 3) and by the action of the hammers on the claws 34. The arrangement may be such that the springs alone return the punches, the claws 34 then being omitted.

The selectors are, however, only allowed to enter their respective slots alternately and then only during certain periods and in response to appropriate signal impulses. This being so the marking and spacing punches are only allowed to operate alternately and then only during certain periods and in response to appropriate signal impulses.

The means compelling alternate operation of the punches during certain periods only and in response to signal impulses comprises the

selectors

35, 36, the cranked levers I9, 20 and the cam groove l4; and the means adapted to associate the signal impulses with the above elements comprises a signal-relay operated element 43 having two

parallel spring tongues

43 and 43 Thecranked levers are provided at the ends furthest from the cam with

rollers

44 and 45. As the levers are alternately rocked by rotation of the cam |2 roller 44 alternately presses on and is removed from the blade spring 40 and roller 45 alternately presses on and is released from the blade spring 4|. The rollers press on their respective blade springs alternately and the pressing on periods and the release periods are equal, this being ensured by the profile of the cam groove M which consists of two equal but opposite runs as shown in Fig. 4 and by the offsetting of the

rollers

23, 24 as previously described. When the rollers press on the blade springs the latter are unable to introduce the heads of the selectors into operative position with respect to the punches.

The'element 43 is of bell crank form. It is pivoted to the plate 4 at 4B and has a pin 41 (Figs. 5 to 10) in its depending arm which pin enters a slot 48 in the reed 49 of the signal relay 50. The relay is a polarised power relay actuated by permanent currents. When the reed 43 oscillates in response to signal impulses the element 43 is oscillated within the limits allowed by stops 5|.

The spring tongues operate on the

tail portions

35 and 36 of the selectors. The said tail portions are notched at 52 (Figs. 5 to 10) and normally project outwardly of the outer face of the plate 4. A double armed blade spring 53 secured to the plate 2 normally urges the selectors towards each other so that the selectors are hooked up on the bottom and the top of the

slots

31 and 38, respectively, when the tail portions project from the plate 4 to a sufllcient extent (see Figs. 1, 6, 8 and 10 more especially). The element 43 isso located that when the top edge of the tongue 43 is beneath the tail portion 35 of the marking selector the tongue 43 is opposite the extremity of the tail portion 35 and when the bottom edge of the tongue 43 is above the tail portion 36 the tongue 43 is opposite the extremity of the tailportion 35 scent-r he'ad 35 int'othe-gap be-tween the-punbh 1 and theopposite or striking fac'e-of the punch ham:- Iner Z'I. I 'Ilhe:parts are th'en in the po'siti'on show nin Figs. 9, 1'0 and 11. I The p'o'sition 'of th'ebafts at the moment "at which the selector 3 5- isnil-hooked 1 is shown in Figs. 7 and 8; r

The cam" :3 then drives the punchham m'er; -s'elector' and mnarking punch forward so that a marking hole and a tape feed hole are perforated (thetape'feed punch 55 (Fig. 3) being rig-id with the hammer 27) and then retracts the hammer; Tho -hammer retracts the selector and the punches I and 55'.

After perforation of the markingh'oletheselector head 35 is Withdrawn from its operative position with respect to the punCh -bytheactiOn of'theroller 44 on the'spring dfl and isfinally" hooked-up owing to the action of the u per blade of the spring 53. This movementof the-selector fiexesthe tongue 43*;

As will :be seen by"r'eference to theparts 43* and 36 in Figs. 9 and i0 the tongue 43 is now in position to 'unhook-the' selector 36 This it does when a chang'e from marking tospacin'g normally occurs; and when the selector 36 -is 4o hooked its head is driven intooperative position with respectto the punch 8 by the spring A I said spring having been released by ther'oller-45; A spacing hole is then punched, the correspond-- ing punch hammer 28- and the'selector'tfi -arid 45 punch 8 are retracted, the selector being again hooked up owing to the aetion of the-roller 45021 the spring 4i andto the'action of the- -lower-blade* of the spring 53 on the selector 36. 1 Theparts' areagain inthe position shown in'Fig's.- 1, 2; 3, 5

and '6 and-theoperations can be repeated ir'i the sequence marking; spacing, marking, spacing and so on but owing'to the alternating action of the

tongues

63 and 43 a spacing hole must always follow amarking hole 'and vi'ce verse, i. e., it is 55'- not possible to miss one signal without the other.

The-marking selector may be unhooked-during interval 3 4, for exampleybut will be-unable-to enter-the operative position with respect --to 'the' markingpunch becausethe spring MI -willstillbe immobilised by the roller; If the :signalis of normal length it may therefore arrive shortly" after moment 2 so long as it extends a fraction of time beyond moment 3 when it will be picked up; It may also be delayed so that-it'does not' ofi start until just before moment 4. As each interval between moments I denoted by "'success'ive numerals corres','po11'd to motion of the cam i i," it can be said that the' pick up range is ap proximately 360:

l'f arortuitous distortion such as a break in a dot-should occiir whilst-the spr-ing ill i's" freed by theroller l i (i. e.,-- during a'marking period) the element 43 will be rocked anti-clockwise owing to stitiient of thebreal's will tlie I v I will'b'e-a changerrom spa'dmg to 11 "Wmact teregistered;

scribed-with reference to Figs? 12 mm The spasm selector will c'b sqiieiitiy ho'oke'd bu he spring 4t the -toner 5'' antttheref the "element{'4 3 win be restored *to position; auowmgthe selectorto'be" agar Y.

- It is "seen thatth brea such breaks curing the bloeke would be registered.

IrrFigs. 12 and-1 3fthe tai1boitionsfoftheinarking and spacing selectors 55 A i aresirni-lai' to thos of I but the heads of the 'selector's' are shouldered =their'extrmities 'a'sat58? Thehamnrers and 2a slide in recesses-macolumn 59 fiXed'to' th N base} i andthe column-carries ramps 60 'h hlieinselectors" 56 'a'nd- 51 are in' the ap between the punches and 1 the opposite faces "of the hammers,

advance Withthe' hammers. springs as M I (Fig 1) te'ndto urge the said -he'ds"ihfi'b'th' said gaps. For the first 180 of easy movement the eads 0f selector 56 from ehtnng its" g movement the "head of selector 151; is; bite of its gap'insihiil'a/Fmannerby the-1p I However, th mar-king Selefidfhaii catfi enterfthe ap between the punch i and the opposite-race 0f the hammer 27 when theflatt'r-is' 'iil-it r:ear

nter

position and the spacing selector head-ca its gap when the hammer'QB is initsrear iib'sitibhl- In other Words the" saidhe'ads are alterii'ately blocked-outer their rsp'ectiveslots for edual periods.

whens mar ing signal is re givee the'selector 5611s unho'oke'cl by the tongue-4'3 arm 'prsvmea the Y selectore st enters the gap bhind'thepunch." The hammer: hes-campuses are thenclri'i'leiiforward and whilst this-takes place-me h'ad is withdrawn from the gap owing to' engagement of th shame ers 58' 011 the said head wit h tlie ubper'afia midm p-5 609 Th'e rainlbs cause-1t to take a =positionwhere the spring 53 can agai'iihook itup; When a spacing' 'signalfollows; "the selector '5'! is un- 'ho'oked,"'a sfi'acing' hon: is perforate and the middle" and" lower ra'rnf'ps 60 and {the spri g-" 53 cause-the said selector tobe-hooked'up again-in a;

manner comparable withi the? described *with referenceto tlie slel'ect'or5fif H g The heads as not; e'rit'irelyieave the slots s n the hammers andfithrefore," reciprocate with the" hammers continuously.

A" further modification 1 of the m mes-Wm new e cles'c'ribedwith reference to; Figs"."1 tem. In-this modification tli altefnat'e'hlockingout r :a a e:

58- when afsiinple bell The punch hammers as 21 and 28 are reciprocated by means comprising a cam groove l3 as described with reference to Figs. 1 and 2 and the

selectors

64 and 65 are urged into the slots 3| in the hammers and withdrawn from them by v springs as 40 and 4| controlled by levers I9 and 20, Figs. 1 and 2. The levers are controlled by a'cam groove as M. A spring as 53 (Figs. 1 and 2) is omitted as the selectors are not hooked up on the plate 4; the tail portions of the selectors simply slide in the

slots

31 and 38 and are hooked up by the lever 66.

The bell crank lever 66 when in the position shown in Figs. 14 and 15 engages a notch 68 in the tail of the spacing selector and when in the other extreme position engages a notch 69 in the tail of the marking selector. The lever 66 is oscillated by a relay as 50, Fig. 5, the reed of which relay engages the pin 10 on said lever and the relay is arranged to rock the lever 66 as viewed in Fig. 14 counter clockwise for marking signals and clockwise for spacing signals.

The latch 6| is pivoted at its centre to a plate H which is secured to a base as I in such a position that when the selectors are in their rear positions (i. e., the positions wherein they are not advanced by the hammers) the axis of the detent 62 is in line with a spring loaded ball I2 and the axis of the detent 63 is in line with a spring loaded ball 14, the balls being mounted in the plate 1|.

The latch is located between the plate and the punch hammers. The balls act as clicks which balls by engaging the sides of the gaps in the latch hold it either in the position shown in Figs. 16, 1'7 and 18 where the ball 12 projects slightly into the upper gap whilst the limb 6| of the latch lies between the ball 14 and the detent 63, or in the position where the ball 14 projects slightly into the lower gap whilst the limb 6| of the latch lies between the ball 12 and the detent 62.

As the punch hammers reciprocate they carry the heads of the selectors with them. In addition the springs as 40 and 4| :controlled by the. bell crank levers as I and 20 tend to cause reciprocation of the selectors.

As marking and spacing'signals (with perfect timing) arrive in succession the detent 62 enters the upper gap in the latch and by engagement with the limb 6| thereof trips the said latch to its alternative position. The detent is withdrawn from the gap before it returns with the hammer by the action of the bell crank lever as IS. A spacin signal then causes the lever 66 to release the spacing selector 65 so that this can be driven into the lower gap. The selector 65 trips the latch to its original position by engaging the limb |i| thereof and before returning with the hammer is withdrawn from the gap by the bell crank as 20. Every time a detent enters a gap in the latch the head of the selector is able to attain its operative position with respect to the punch. Therefore,. punching is effected. The spacing signal causes the lever 66 to engage the marking selector but the following marking signal releases the said selector and causes the lever to engage the spacing selector. And so on. Thus, signals are recorded in the order marking, spacing, marking, spacing, and so on but fortuitous distortions cannot be recorded as during possible marking signal accepting periods the detent 63 is blocked by the limb 6| and during possible-spacing signal accepting periods the detent 62 is blocked by the limb fil marking signal accepting periods occurring during 180 of cam rotation and spacing signal accepting periods occurring during the next of cam rotation and so on.

In the case of signals longer than a dot, such as dashes, holes should only be perforated at each change of polarity in the signals, and the sequence will be as follows: The marking selector Will first be released by the lever 66 and the spacing lever arrested by the same lever. The marking punch will perforate a hole in the tape, and the latch 6 will be thrown so that limb 6 covers ball 12. During the second half revolution spring 4| will urge the spacing selector 65 forward but this selector is prevented from moving by the locking action of the lever 66, consequently no further movement of the selector takes place. During the third half revolution the marking selector 64 is urged forward by spring 40 but is prevented from causing a perforation of the tape by detent 62 hitting against limb 6|. Not until the fourth half revolution will a perforation take place, namely of a spacing hole which follows on the release of the spacin selector by lever 66 being operated by the change marking-spacing occurring at the end of the dash signal.

The selectors may be operated by individual relays.

The invention may be applied to telegraph receivers of any suitable kind operating on the Wheatstone (Morse) system of signalling.

What I claim is:

1. In a telegraphic receiving instrument for code signals for the Wheatstone (Morse) land line system of signalling in which each code element is an uneven multiple of the shortest signal and hence changes from spacing to marking can only occur at different instants from marking to spacing, a relay responsive to received signals, a cam synchronised to the signals, mark and space means, means operable by said cam to actuate said mark and space means, selectors operable by said cam to control the actuation of said mark and space means and means whereby the relay also controls the selectors whereby signals received at (correct times permit movement of the selectors by said cam to effect operation of the mark or space means.

2. In a telegraphic receivin instrument for code signals for the Wheatstone (Morse) land line system of signalling in which each code element is an uneven multiple of the shortest signal and hence changes from spacing to marking can only occur at difierent instants from marking to spacing, a relay responsive to received signals, a cam synchronised to the signals, mark and space means, actuators for said mark and space means operated alternately by the cam, selectors to control operation of the mark and space means by said actuators, springs acting to move said selectors into operative positions, selector control means operated by said cam alternately with said actuators and adapted to free the selectors for movement by said springs and means to further control the movement of said selectors from said relay whereby said selectors are free to move to operative positions only on receipt of a correctly timed signal.

3. In a telegraphic receiving instrument for code signals for the Wheatstone (Morse) land line system of signalling in which each code element is an uneven multiple of the shortest signal and hence changes from spacing to marking can only occur at different instants from marking to spacing, a relay responsive to received signals, a cam synchronized to the signals, mark and space punches, strikers operable by said cam to actuate said. mark; and. space punchesaIternateIm:mark

and space-selectors operable alternatelyoqby'rsaid cam to control the actuation'o'fsaid. mark and space punches respectively, latch means to retain said selectors in non-operative positions and means whereby the rela-y'also controls the release of said selectors fromsaid latch means whereby signals received at correct times permit movement of theselectorsbysaidcam to-efiect operation of the mark or space punches.

4. In a telegraphic receiving instrument for code signals for the Wheatstone (Morse) land line system of signalling inwhich each codeelsment is an uneven multiple of theshortest. signal.- and hence changes iromspacing, to marking can only occur at difierent instants from marking-to spacing, a relay responsive to .received-signalsa cam synchronised to the signals, mark andspace punches, actuators for said mark and space punches operated alternately-by the cam, selectors to control operation of thewmark and space punches by said-actuatorssprin'gs acting to move said selectors into-operative positions, selector control means operated by'said. camalternately with said actuators andzadaptedto free .theselectors for movement by saidsprings, latch means to prevent movement of such selectors and means actuated by said relay to control the'unlatching of said selectors to makethem 'free'to moveand whereby they move by said springs to theiroperative positions only on. receiptmof: a oorrectly timed signal.

5. In a telegraphic, receiving 'instrument for code signals for the Wheatstone (Morse) land line system-t signalling. in whicheach codei element is an uneven-multiple .of the shortest signal and hencechanges from spacing to marking-can only occur at different instants from marking to spacing, a relayresponsive to received signals, a two part cam synchronised to-the signals, mark and space-punches;independent actuators for said mark and space punches operated'alternately by one cam part, mark and space selectors to control operation of the mark and space'punches by said actuators, springs'acting to move said selece tors into operative. positions, mark and-space selector control means operated by the-other cam part alternately with said actuators andhadapted to permit the selectors 'to move by said springs,

latch means to retainsaid selectors in inoperative:-

position and 'rneans'to'control the release of said latch means from said relay, whereby a selector, released on receipt of a-signal, only moves into operative position if permitted bythecontrol means and only for a correctly received signal.

6. In a telegraphic receivingiinstrument for code-signals-forthe Wheatstone- (Morse) land line system of signalling in which each'code' element is an uneven multiple of the shortest sig nal and hence changes from spacing to -marking canonly occur at different instants from marking'to spacing; a relay responsive to received signals, a. two part cam synchronised to the signals, mark and spacepunches, -independentactuators forv said mark andspace; punches operated alternately byone camtpart, mark and space selectors to control: operation of the mark and space punches by said actuators, springs acting tomove said selectors into operative positions; mark and space selectorcontrolmeans operated alternately;

by said cam said operations occurringalternately with said actuators and-timed to provideapossible period of cooperation of the:mark-selector, actuator and punch which. is equal to and alternate with a possibleperiodrof cooperation: of the 10 space selector, actuator and punch, means to retain said selectors in i-noperative positions and means operated bysaid-relay to free said selectors to permit themto move to'operative positions when permitted by the selectorcontrol means.

7. In a telegraphic receiving instrument for code signals for the Wheatstone '(Morse) land line system :of signalling in which each code element is an'uneven multiple of the shortestsignal and hence changes from spacing to marking can only occur at different instants fromma-rking to spacing, a relay responsive to -receivedsignals, mark and spacepunches, mark and space selectorsin cooperative relation therewith, mark and space strikers for said punches acting through the intermediary of said-selectors when in operative positions, a cam synchronised to the signals, means operated by said cam to operate the mark and space strikers alternately, further means operated by said 'cam to move alternately saidmark and space'selectorsout-ofthe operative positions inrelation to the respective punches and strikers, spring means actingto move the selectors into theoperative positions, meansto retain the'selectors in positions-where the strikers are inoperative to act on the punches and means controlled -by the signal relay to-de termine the release of saidselectors to-permit them to move alternately under the control of the said further means, so that a correctly received signal releases the appropriate'selector at the same time that saidselectoris-al-lowedto move by the said furthermeans.

8. In a telegraphic receiving instrument for code'signals for the- Wheatstone' (Morse)= land line system of 'signallingin which each code element is an-uneven multiple of theshorte-st signal spacing, a relay responsiveto received signals,

mark and space punches, mark and space selectors movable into cooperative relation therewith, mark and-space strikers for saidpunches acting through the intermediaryof said selectors when in operative positions, a cam synchronised to the signals, :cam V followers engaging said cam to operate'the mark and-space strikers alternately so that such strikers are'operated; at cyclic intervals when mark and space conditions couldoccur with a correctly received signal,- iurthercam followers engaging-said cam to move saidmark and space selectors alternatelyone with the other and alternately with the movement of the strikers such movement of the selectors being out-0f the operative positions in relationtothe punches and strikers, spring means acting to move the selectors into the operative positions, latch means to retain theselectors ininoperative positions where the strikers are inoperative to act on the punches and means controlled by the signal relay to determine the release of said selectors to-permit them to move alternately under the control of the further cam followers, the latter being timed by the cam in relation to atrain of received signalsso that a correctly-received signal'releases the appropriate selector at the same time that said selectoris allowed to move bylthe cam follower concerned.

9. In a telegraphic receiving instrument-for codesignalsfor the Wheatstone (Morse) landline system of signalling inwhich each code element is an uneven multiple'of-theshortest signal and hence changes from spacing tomarkingcan only occur at different instants from marking to spacing, a relay responsive to received signals, mark and space punches, mark and space selectors movable into cooperative relation with said punches respectively, mark and space strikers for said punches acting through the intermediary of said selectors when in operative positions, a cam synchronized to the signals, cam followers engaging said cam to operate the mark and space strikers alternately so that such strikers are operated at intervals when mark and space conditions respectively could occur with a correctly received signal, further cam followers engaging said cam to move said mark and space selectors alternately one with the other and alternately with the movement of the strikers such movement of the selectors being out of the operative positions in relation to the punches and strikers, spring means acting to move the selectors into the operative positions, latch means to retain the selectors in inoperative positions where the strikers are inoperative to act on the punches and means controlled by the signal relay to determine the release of said selectors to permit them to move alternately under the control of the further cam followers, the latter being timed in relation to the received signals so that a correctly received signal releases the appropriate selector at the same time that said selector is allowed to move by the cam follower concerned and before the relevant striker operates to actuate the corresponding punch.

10. In a telegraphic receiving instrument for code signals for the Wheatstone (Morse) land line system of signalling in which each code element is an uneven multiple of the shortest signal and hence changes from spacing to marking can only occur at diiferent instants from marking to spacing, a relay responsive to received signals, mark and space punches, mark and space selectors movable into cooperative relation therewith, mark and space strikers for said punches acting through the intermediary of said selectors when in operative positions, a shaft synchronized to the signals, a first cam on said shaft, followers engaging said cam to operate the mark and space strikers alternately, a further cam on said shaft, further followers engaging said further cam to move said mark and space selectors alternately at time intervals intermediate between the operation of the first-named followers by said first cam such movement of the selectors being out of the operative positions in relation to the punches and strikers, spring means acting to move the selectors into the operative positions, latch means to retain the selectors in inoperative positions where the strikers are inoperative to act on the punches and means controlled by the signal relay to determine the release of said selectors so that a selector released by a correctly timed signal moves to the operative position whereas a selector released by an incorrectly timed signal, is freed at a moment when movement is prevented by the appropriate further follower.

11. In a telegraphic receiving instrument for code signals for the Wheatstone (Morse) land line system of signalling in which each code element is an uneven multiple of the shortest signal and hence changes from spacing to marking can only occur at different instants from marking to spacing, a relay responsive to received signals, mark and space punches, mark and space selectors movable into operative positions in cooperative relation therewith or into a disengagement position, mark and space strikers for said punches acting through the intermediary of said selectors when in operative positions, a shaft synchronized to the signals, a first cam on said shaft, followers engaging said cam to operate the mark and space strikers alternately, a further cam on said shaft, further followers engaging said cam to permit disengagement of said mark and space selectors alternately and for equal time periods, the movement of the strikers being timed to occur in course of periods alternating with the periods of disengagement, spring means acting to move the selectors into the operative positions, latch means to retain the selectors disengaged independently of said followers and means controlled by the signal relay to determine the release of said selectors from said latch means to permit them to move if so permitted by the further followers.

12. In a telegraphic receiving instrument for code signals for the Wheatstone (Morse) land line system of signalling in which each code element is an uneven multiple of the shortest signal and hence changes from spacing to marking can only occur at different instants from marking to spacing, a relay responsive to received signals, mark and space punches, mark and space selectors movable into operative positions in cooperative relation therewith or into a disengagement position, mark and space strikers for said punches acting through the intermediary of said selectors when in operative positions, a shaft synchronized to the signals, a first cam on said shaft, followers engaging said cam to operate the mark and space strikers alternately, a further cam on said shaft, further followers engaging said cam to permit clisengagement of said mark and space selectors alternately and for equal time periods, the movement of the strikers being timed to occur in course of periods alternating with the periods of disengagement, spring means acting to move the selectors into the operative positions, latch means to retain the selectors disengaged independently of said followers, means controlled by the signal relay to determine the release of said selectors from said latch means to permit them to move if so permitted by the further followers, a paper guide to present paper in punching position in relation to said punches and means operated by said shaft to feed such paper in stepwise manner.

13. In a telegraphic receiving instrument for code signals for the Wheatstone (Morse) land line system of signalling in which each code element is an uneven multiple of the shortest signal and hence changes from spacing to marking can only occur at different instants from marking to spacing, a cam synchronised to the signals, mark and space punches, strikers operable by said cam to actuate said mark and space punches alternately, mark and space selectors, said selectors being notched near their free ends, springs acting to move said selectors axially to a position providing cooperation between the strikers and the punches, a latch plate having apertures the edges of which are engageable by the notched parts of the selectors to retain the selectors in retracted positions, means operated by said cam to move said selectors alternately and against the action of said springs into the said retracted positions, a signal relay, an element operated thereby and movable in a plane intersecting the ends of the selectors, and flexible tongues on said element engageable with said selectors, the overall width of said tongues being greater than the distance between the selectors so that at ever instant when the selectors are retracted one tongue is flexed by the end of one selector and the other tongue is positioned to release the other selector REFERENCES CITED The following references are of record in the file of this patent:

5 UNITED STATES PATENTS Number Name Date 1,543,906 Creed June 30, 1925 1,827,460 Creed et al. Oct. 13, 1931 19 1,942,588 Bancroft Jan. 9, 1934