US1858511A

US1858511A - Automatic telegraph keying head

Info

Publication number: US1858511A
Application number: US539334A
Authority: US
Inventors: Kunc Frank; Knopp Ernest
Original assignee: H O BOEHME Inc
Current assignee: H O BOEHME Inc
Priority date: 1931-05-22
Filing date: 1931-05-22
Publication date: 1932-05-17
Anticipated expiration: 1949-05-17

Description

May 11, 1932. g. KUNG ET AL 1,858,511

AUTOMATIC TELEGRAPH KEYING HEAD Filed May 22, 1951 6 Sheets-Sheet l W vm' TTORNE May 17, 1932. i F KUNG ET AL 1,858,511

AUTOMATIC TELEGRAPH KEYING HEAD .Filed May 22, 1931 A6 VShee'lZS-Shet 2 I -p INVENTOR5 May l`7, .1932. F. KuNc ET AL.

AUTOMATIC TELEGRAPH KEYING HEAD I Filed May 22, 1931 6 sheets-sheet 3 I mrAoRNEYs May n17, 1932. F, KUNC E1- ALy 1,858,511

AUTOHTIC TELEGRAPH KEYING HEAD Filed May 22, 1931 6 Sheets-Sheet 4 QL l.

I -gimz .N

INVENTRb Mm c;

' ORNE@ May 17, 1932. n F, KUNC ET AL 1,858,511

ATOIIATLC TELEGRA-PH KEYING HEAD iled' Hay 22. 1931 6 Sheets-Sheet 5 NIV, un., o

I 'i llllll nmlu www Imi-ilu i o dm- TToRNEYs,

May 17, 1932. F. KuNc E-r Al. 1,838,511

AUTQIIATIG TELEGRAPH KEYING HEAD Filed lay 22, 1931 6 Sheets-'Sheet 6 o "Hill BY s. mi y /l M ATToRNL-:Y5

m/ Y ENToR;

Patented May 17, 1932 Unirse sT-A'ijas PATENT vcitric-121 FRANK KUNG, OF NW ROCHELLE, .AND ERNEST KNOPIRA OF BRONX, NEW YORK, ASFkv SIGNOBS TO H. 0. BOEHME, INC., OF NEW YORK, 1\l'.` Y., A CORPORATION OF NFN' YORK 4AU'roiiiaTic TELEGRAPH Karinel HEAD' Application ledMay 22, 1931. Serial'No; 539,334.

'f rela-tein particular to the mechanical construction of such keys by which we areenabled to operatethe key at a much higher speed than is possible, so far as we are aware, with the keys at present in use.

i The present day automaticV keys either make or break the contact` or dol both, by spring power, and only the mechanism which controls the springs is positively operated. As soon as a certain operating speed is attained by such a. key, natural oscillations are set up in the contact mechanism, due to the elasticity of the springs and the masses Vwhich they control, which oscillations seriously interfere withthe pi'oper timing of the contacts, with respect to their make and break, so that for instance Morse dots and dashes become very irregular and indistinguishable from one another.

In our improved automatic keying mechanisin these difliculties are overcome by positively gearing and operating at all times all elements of the mechanism which are directly concerned in. the movement of the Contact l arm. so that this arm is at all times only` positively moved, whereby the operating speed ot the key can be increased to several times the speed of the keys at present in practical use for line or radio transmission. A Our invention is illustrated in the accompanying dra-Wings in which; Y

Fig. l represents a top plan view of the keying head; Y v

Fig. 2 represents a front view of the keying head with parts broken awayto showt7 the lcontact mechanism 1 Fig. 2a represents a detail in greatly enlarged. partly vertical sectional view, of the toggle joint inFig. 2, for holding-the con- Fig. 4-represents a rear view of the keyingv head, with parts broken away to show the gear drive;

Fig. 5 representsaplanview of the-selector lever gear housing in larger scale;

Fig. 6 represents a vertical section ofthe saine housing on the same scale taken on the line 6 6 of Fig. 8; i

Fig. 7 represents*axliorizontal section of the lever housing through the lever pivots on s Fig. 8 represents a front viewo the-lever housing in the same scale with front cover removed, showing the selector pin levers in a position in which both selector pins are drawn furthest apart, `pin s receding from,

pin m advancing into a hole in drum 20, con'- tact arm on lower (spacing) contact;

y Fig. 9 represents the same view as Fig. 8, `with the driving crank pin l for the selector levers advanced over Fig. 8 one-quarter turn to position II, showing the marking selector pin'madvanced completely intov a hole of the selector drum, contact arms still down,

spacing selectorpin withdrawn `from selector drum hole, contact arm about to be lifted from spacing contact S; Y y Fig. 10 represents the same View as Fig. 8 with crank pin advanced another one-quarter turn to position III, both selector pins iii transverse alignment, contact-arm has beenV moved up to marking contact M, pin m about to withdraw from, pin s advancing into drum Fig. 11 represents the same view as Fig. 8.

With'crank pin'advanced another one-quarter turnto positionlV, spacing selector pin s advanced completelyfinto selector drum hole,

pin my completely withdrawn, contact armv still Yup, ready' t Fig. 12 represents a greatly enlargedhorizontal section through the lower contact block 72 'of Fig.V 2'; v j,

Fig. 13 represents a greatly enlarged frago return to spacing contact 1 95 menta-ry vertical section through the contact block tip on the line 13-13 Fig. 12;

Fig. 14 represents a greatly enlarged fragmentary detail of the tape drive seen in plan in Fig. 1;

Fig. 15 represents an exploded perspective view of the contact lever and its interlink- -ing lever shown in Figs. 8 to 11;

Fig. 16 represents a front view of the selector lever housing in reduced scale, showing the eccentric mechanism for throwing lector pins with relation to each other and with the selector drum, v

' Fig. `19 showing the spacing pin s ing from, and the marking pin m advancing through a hole in the tape, into a selector drum hole (corresponding to position Fig. 8 i i' i )Fig 2O showing the marking pin m' entirely advanced, spacing pin s entirely withdrawn, rotation of selector drum about to carry pin fmy to left to throw contact lever up, (corresponding to position Fig. 9),

Fig. 21 Vshowing the spacing pins advancing, marking pin m retracting (corresponding to Fig. 10),' Y

5 Fig. 22 showing the spacing pin s entirely advanced, marking pin m entirely with# drawn, rotation of selector drum about to carry in s to left, to throw contact lever down corresponding to Fig. 11),

'i Fig. 23 showing the relative' position of selector pinsA as in Fig. 22, but prevented from entering drum holesfwhen tape has no-A perforations Fig. 24 represents a fragment of a perforated transmitting tape, to show spacing of telegraph code symbols, and

. telegraph code.

Fig.25 represents a similar fragment of a receiving tape on which the transmitted symbols are recorded in dots and dashes of the Discussing first the-underlying principle of the conventional perforated tape control for automatic keyingreference,is made to Figs. 24 and 25 and to the circuit diagram shown in Fig. 16., In this latter ligure for example a direct current source D. C.` is employed at the transmitter end of the system, shown in that figure, across which source a resista-nce fr is connected which is tapped in the center. One e'nd of At-his resistance is connected A to the retractspacing contact S of the transmitter key, and the other end of the resistance is connected to the marking contact M of the key. The center of the resistance is connected to one terminal of the receiving coil at the distant receiver, the other end of this coil being connected to the contact A of the contact arm which operates between the two contacts by the function of the key mechanism which will be described later. If for instance the arm contact A is thrown onto the spacing contact S, a current flows from the center of the resistance, through vthe line, in the direction of the righthand arrow through the receiver coil and through the other side of the line over contacts A, S to the minus side of the source. If the arm contact A stands on the fmarking contact M, the current flows in the direction of the left hand arrow through the distant receiver coil. Thus, according to the position of the key contact arm, the distant receiving coil, by means well known in the art and not shown here, causes the throw of an inked pen p to one or the other side of a moving receiving tape, of the character shown in Fig. 25.

The time for which the pen remains on one or the other side of the tape depends upon the duration of the contacts between contact A and S or M. When contact is made for a certain len th of time at M, for instance one of the mar (ings a2 heavy lined in Fig. 25 produced on the receiving tape which represents a code dash. )Vlien cont-act is made at S, the pen swings to the other side of the tape and now the first of the spacing symbols b2 is produced which spaces the iirst code dash a2 from the second following'dash a2. Vhen marking contacts of shorter duration areV made, code dots such as c in Fig. 25, followed by spaces, the same as 52will bev produced.

-If the contact arm remains a comparatively long time on the' spacing Contact, long spaces, such as between words, shown at b1 in Fig. 25

.are produced'.

The correspondingly perforated tape shown in Fig. 24 when fed through the transinitter keying head according to the present invention, permits two suitably disposed selector pins, one for each longitudinal row of holes, to enter the perforations and a pin Vconveying drum in a manner to be described presently, and while a pin remains in the perforation and in the drum, and the latter with tape continues to travel, the pin is taken along laterally a certain distance and by its tilting causes the contact A of the key to move on one or the other contact and to produce the signals referred to hereinabove.

`F or instance, a selector' pin entering the iiist marking hole f1.2 in Fig. 24 would be taken to the left with the travelling tape and by the mechanism to be described would closeI immediately the marking contact which remains closed (thereby producing the first dash a2 in Fig. 25) until the other selector -mounted the selector lever box 12 pin encounters the next spacing hole 2in Fig. 24, when the Contact arm is thrown at once onto the spacing contact to produce the first space b2 in Fig. 25, which ends` when the marking pin encounters the second marking hole ca which throws the contactarm back onto the marking contact of the'key, and so forth. The two tape fragments in Figs. 24 and 25 are shown vertically above one another and the ti'acing produced by the receiver pen p according to each particular transmitter tape perforation shown in Fig. 24, is shown immediately below in Fig.

lith this preliminary explanationin mind. the mechanical construction and function of the keying head will now bedescribed.

The keying head consists of four'principal mechanisms: tie selector pin operating lever mechanism shown in detail in Figs. 6 to 11; the driving gear trains for the lever mechanism, shown in detail in Figs. 3 and 4; the contact lever mechanism, shown in Fig. 2; andY the tape release mechanism shown in Figs. 2, G, 16, 17 and 18.

Referring first to the driving gear trains and to Figs. 1, 2, 3 and 4, the keying head comprises a main box 10 which contains the driving gear andwhich is mounted on a base plate 11, as shown more particularly in Fig. 2. On the front of the main box 10 is' and adjacent to the latter the contact box 13.

The driving gear in main box 10 comprises a driving shaft 14 which protrudes at the rear of the box as shownvin Fig. 3 carrying at its outer end a saw tooth coupling 15 by which it is coupled to the conventional driving mechanism used in this type of'keyfnot shown). Through a train of step up gears 16 shaft 14 drives the main operating shaft 17 which extends intothe selector lever box 12, and which will be referred to later. Through another train of step down gears 18 shaft14 drives the selector drum or tape drum shafty 19-on whichis mounted at the front of box 10 the selector or tape drum 20 right above the selector lever box 12. This selector drum, shown more detailed in Fig. 14, is provided with a gear 21 at the outside of box 10 which meshes with a gear 22 integral with the star wheel roller 23, the pin teeth 24 of which engagethe central row of perforations of the tape 26 shown in Fig. 24, when the tape is laid around the lower portion of the tape drum periphery as shown in Fig. 2. The pin teeth 24 run freely in a groove 27 provided in the tape drum 20. By this last described gearing the tape is positively driven with re- ".pect to the drum 20, so that the perforations in the two outer rows of the tape when present, will always precisely register with the two rows of selector pin ho`1es'28 and 29 provided in drum 20; An idling roller 30 is pro vided on the other side of drum 2O` by which are mounted in a frame the tape 26 is guided onto and held on drum 20. The star wheel roller 23 and idling roller 30 are respectively mounted on

arms

31, 32, the upper ends of which tached tothe front of main casing 10. They are held in the position shown in Fig. 2 by means of a tension spring 34 shown in in dotted lines, thereby pressing the star ywheel roller and the idling roller against the tape and selector drum 20. The release of this mechanism for insertion or removal of tape 26 will be described later. Arm 31 is provided with a stripper 33, the end of which extends close to the roller 23, straddling the teeth of this roller are pivotally at-l rige.v

periphery of star wheelY v l 8o l as shown in Fig. 1, for the purpose of prompt ly freeing the tape from the star wheel teeth and to facilitate the smooth running off of the tape in the direction of the arrow shown in Fig. 2. From this gear drive, so far de# scribed, it will be observed that the selector lever operating` shaft 17 all gear wheels run in ball bearingss'uch asl shown :at 35, and in order to facilitate the (Fig. 3) and the tape or selector drum20 and the tape feeding mounting of the gears, the twoigeartrains 16 drive shaft 14 36 which is inserted of gear box 10 as shown in and 18 together with the main into the rear wall Figs. 3V and 4. Referring now to the selector pin operating mechanism, contained in lever box 12 this Vmechanism is constructed as follows. Referring to Figs. 6 to 11, and in particular to Fig. 8, 17 is the drive shaft for this mechanism, previously described as extendingV from main box 1() into selector levery box 12 as shown in F ig.6. In the lever box 12 and mountedabove shaft 17 is a transverse pivotal shaft which has a thin portion 38 ex- Yma tending through a guide bushing 39'bey0nd the front of box 12, and which is" also pro'- vided with a thick portion 40 journalled' in the rear wall of box 12. 41 of this shaft is eccentric for reasons to be described later on. and the thin end 38 of'the shaft are shown in F 8 to 11 in end view. The eccentric portion 41 serves as-a pivot for a rocking frame42 which has a forked lower end in which a guide block 43 which block engages a pintle 44 eccentricallydisposed at the end Vof gear shaft 17 (see also Fig. 6).

driving Thus when shaft 11o ff The central portion f Theeccentric portion 41 is slidingly disposed i 17 revolves, rocking frame42 is rockedon eccentric '41 from one siderto the other, as-

suming successively shown in Fig. 8, then the inclined position another one-quarter turn again a central posithe central position after one-quarter turn tion shown in Fig. 10, and after another one- Y an' inclined position shown in Y e 130 A quarter tif-,rn Fig. 11.

shown in Fig. 9, after Rockinglframe 42 has near its'pivot point two lateral extensions 45 and 46 which carry respectively the two transverse pivot pins 47 and48. lBy these pivot pins the selector pin levers 49. and 50 respectivelylare attached to the rocking frame 42, forinstance as shown atithe left hand side of Fig. 8, means of a transverse sliding block 51, `which can slide in the transverse slot 51a provided in each frame.V These levers which have the shape of iframes, are guided respectively by guide blocks 52, 53. Guide block is `fixed-tio an interlinking-lever 54, and guide block 53 to contact lever 55, which latter protrudcs through the wall of box 12, its outer end cooperating with contacts M and S. The shape of theseV two lastA mentioned levers is shown more clearly'in anexplodcd perspective view in Fig. 15. These two guide blocks and levers are pivoted each on a separate axle 56, the axles extending from the rear wall through box 12 (see also Fig. 6) on which axles theA levers can freely rock. The two levers are besides interlinked by means of a pin 5T which is located in a sliding block 58 slidingly mounted inthe rear end of lever 55. These elements are very clearly shown in Fig, 15. From this interlinking it becomes obvious that when one lever is rocked clockwise the other will be rocked counter' clockwise, and vice versa. The guide blocks 52, 53 of these two levers, which, as was stated before, serve as longitudinal guides for the respective selector pin frames49 and 50, are set with respect to the longitudinal axis .of their pertaining levers at an angle, as appears for instance from Figs. 8 and 15,'so that the two selector pin framesy stand inclined towards one another. 'Assuming for themonient that interlinking lever 54 and contact lever 55 are held stationary and rocking frame 42 is rocked' from one side to the other by main drive shaft 17, the two selectorV pin frames 49 and-.'alternately merely move up and down longitudinally, so that their respective selector pins m and s which protrude from their upper free ends movebalternately into and outof the hollow tape bridge 60 which is mounted .on top of gear box 12.`For this purpose the top of the bridge, which closely follows the contour of the tape or selector drum 20, is provided with

slots

61 and 62 respectively (see also Fig. 5).`

As shown for instance in Fig. 8, each of `the selector pins mand s is longitudinally Guided in its pertaining frame and is provided with a collar 63 which is located inside of theframe. The inner end of each pin is guided in a hole 64 provided in the pertain- 'ing frame guide block. Between the guide blockand the collar is arranged a spring65 whichtends to keep the collar in contact with the inner upper end of the frame, and thereby tends to maintain the pin pushed` out of the frame as far as possible. Thus, when such avselector frame is retracted by the rocking motion of rocking frame 42 its selector pin is retracted with it against the tension of its spring. The description of this frame construction has been made only with respect to frame 50, it is the same with respect to the other frame 49.

As will also be noted from Figs. 8 to 11 and also from'Fig. 6, the two selector frames 49 and 50 are pivotally attached to rocking frame 42 at opposite sides, frame 49 being attached to the rear of frame 42 in Fig. 8, and

'marking pin m is located to the rear, and the spacing pin s at the front (see alsoFig. 5). The selector drum 20, around the lower portion of which the tape runs, and with the A holes 28 and 29 of which the perforations in the tape-if present-register, ashas been described hereinbefore, is positively geared and timed with relation to the rocking motion of frame 42, so that for instance when the spacing pin m in Fig. 8 commences to protrude through its slot in the tape bridge l60, a hole 29, shown in dotted li-nesin Fig. 8,

has arrived in line to permit the marking pin m to enter. The row of marking holes'A 29 are drilled into drum 20 at an angle to the drum radius so that' when the marking pin m has arrived near, or at the bottom of a hole. as shown in Figs. 9 and 20, it will come in contact with the wallof the hole at the right hand side, so that when drum 20 continues revolving in the direction indicated by the ar-` row in Figs. 8 to l1 and Fig. 20, marking pin m will be taken along to the left into the position shown in Fig. 10. In other words,

guide frame 49 of marking pin m, aside from l performing a longitudinal motion due to the operation of rocking frame 42, Twill also swing to the left on its pivot stud 56 from the position in which it is shown in Fig. 8 to the position in which it is shown inV Fig. 10. Since the guide block 52 of frame 49 is .rigidly attached to -interlinking lever 54, this leverk is rocked counter clockwise from the position shown 1n Fig. 8 into the .position shown iny Fig. 10 which, due to the interlinking of leven 1

V ers

54 and 55, will cause contact vleVl 55 to rock clockwise to the Vsame langular vextent from the position shown in Fig. 8 lto the poy sition shown in Fig. 10; In other words, `whereas in'Fig. 8 the outer end of contact lever 55 which protrudes to the left beyond casing 12 is in'contact'with the spacing lcontact S, it has been'thrown by the 'aforemenida. .i

tioned rocking motion upward into the posiy .y

tion shown lin Fig. 10 :where it'makes Contactv with the marking contact of the key. The detailed construction of these contacts will be referred to shortly hereinafter. While the marking pin m, has just been described, enters one of the marking holes 29 of drum 20, frame 50 of spacing pin s moves longitudinally downwardly into the position shown in Fig. 9, whereby ith-as `retracted its pin s from the spacing hole 28 of drum 20 in which it is shown in Fig. 8, so that the tip of the pin is below the surface of tape bridge 60. This permits the aforedescribed rocking of frame 49 by drum 20 to the left; When contact arm 55 swings upwardly from the position in Fig. 8 to the position in Fig. (l0, frame 50 ofthe spacing pin s rocks with arm 55 clockwise into the position shown in Fig. l0 in which the tips of the two pins m and s are shown in transverse alignment, which is the closest approach of the pin tipsto one another, whereas in Fig. 8 they are shown furthest apart. In Fig. 8 with the contact arm on the spacing contact S, and the selector pins m and s are always drawn furthest apart. and are in spacing position, whereas in Fig. l0, wthcontact arm 55 .on the marking contact, `the two selector pins m and s are in marking position. In 9 the pins, so far as the tilting ofthe two frames 49 and 5() is concerned, remain Still in spacing position in which they are `shown in Fig. 8. and their pertaining selector frame only performs a longitudinal motion to either withdraw its pertaining pin from aihole in drum 20, or to advance its pin into it, as the case may be. Similarly in Fig. 1l the two pins m and s, together with their pertaining frames remain in the same marking position shown in Fig. 10, and in the position 1l, the frames only perform longitudinal motion to withdraw a pin from, respectively advance it into one of the holes.

vWhile marking pin m has been tilted by drum 20 from the position shown in Fig. 9 into the position shown in Fig. 10 to cause arm 55 to make a marking contact, rocking frame 42 has gradually arrived in the position shown in Fig. l0, in which the marking pin m is still in its marking hole, but in which the spacing pin s has been in the meantime partway advanced into a spacing hole which is transversely in alignment with the marking hole in which the pin m is located at the time. This has been made possible by the tilting of pin s from the position shown in Fig. 9 into position shown in Fig. l0, in which it mee-ts the hole as it were. Itwill be noted from Figs. 8 to llas well as from Figs. 19 to .23 that the holes in drum 20 are substantially larger than the diameter of the pins, so that these pins can start entering the holes which they encounter quite early, without striking the edges. Furthermore, it should be noted that the marking holes 29 are inclined at an angle to the drum radius, while the spacing holes 28 extend substantiallyin radial direction. This is necessary, because the marking pin m is inclined in the direction of the drum rotation, while spacing pin s is inclined more or less against the drum rotation. 1n order that each pin should encounter the hole Wall first near the hole bottomfso as to stay contact with the wall as long as possible in order to tilt frames Li9 and 50 at the largest possible angle, the holes 29 must hey inclined as described. T his Willbe obvious especially clearly from Figs. 19 to 22.V i When the rocking of frame Al() continues clockwise, spacing pins is pushed gradually to the bottom ofthe spacing hole 28 which it-has entered in Fig. l0, and when this happens (as showin in Fig. l1) pin s is taken along drum 29V in vthe direction of the arrow and tilted to the left back into thel position shown in Fig. S. By kthis tilting frame 50 of pin s, together with contact lever 5 5 is rocked counter clockwise so that the contact lever is thrown from the marking contact M back to thespacing contact lS as shown in Fig.` .8. Through the interlinking between

levers

55 and 54, the latter lever-is rocked clockwise, and thereby rocks the guideframe 49 of marking pin m (which latter inthe meantime has been withdrawnfrom its hole) to 'theiright into the spacing position shown in Fig. 8, in which it is readyto Ameet the next marking hole 29 as shown in Fig. 8.* From the position of the

pin slots

61, 62 inthe tapebridge shown in plan in Fig. 5, it will be observed that the tilting range of spacing pin s is set slightly beyond the tilting range yfor the marking pin m in the direction of the `selector drum rotation. This is arranged so that when a marking contact is made as in Fig. llhfor instance due to the `first marking perforation c in Fig. 24, and immediately thereafter a spacing contact should occur, in order to produce a short code dot, as shown by the first hole Zin Fig. 24, the spacing pin s is in a position to enter this first perforation d, i.

land the corresponding hole 2S in drum 20 as shown in Fig. `l0, so as to promptly `throw the contact lever onto the spacing contact. n From these movements so far described it will, therefore, be clearly seen that the function of rocking frame 42 is to advance the pins m and s into, respectively out of engagement with selector drum 20 without any effect upon the .contactposition of arm 55,

whereas the function of drum QO-is to posi- 15"' tively tilt the `frames 49 and 50 toward or away from one another, and to thereby directlyaffeet the position of contactarm 55 with respect to contacts M and S. i l

Since the engagement of drum 20 by the pins depends upon the presence of a perforation in the tape, it follows that the position of contact arm 55 with respect to the marking and spacing contacts M and -S is directly controlled by the presence or absence of-V perfforations in the tape in Fig. A24. For instance, in Fig. 22 in which the spacing pin s' is shown in a marking hole 28 c-f drum 2O (see also Fig. 11) ready to be carried by drum to the left in order to throw contact lever 55 from the marking contact M in Fig. 11

` onto the spacing contact in Fig. 8, this throwing of the contact arm cannot occur in the case, witha similar position of frames 49 and V, land a similar tilting of pins 8 and m,

fshbwn in Fig. 23, Where the tape has no perf'ortion, so that the spacing hole 28 in the igiire, which-is inthe same position of spac- "ing' hole 28 of Fig. 22, is coveredby the tape. In that case, instead of advancing into hole 2 8 when its'frame 50 advances, pin sis pushed back into the frame, as shownin that figure, against the tension of its spring 65. Drum 20 now continuing to rotate in the direction of the arrow, hole 28 passes by the tip of pin -s without having tilted frame Y5() and, therefore, without having thrown contact arm from the marking to the yspacing contact. This missing of holes continues until a spacing perforationV arrives through which pin s can enter into a spacing hole 28 such as is shown in Fig. 22. This condition vice versa prevails when the contact arm happens vto standen ay spacing contact brought about -tion of the arrow shown in that figure, neither the spacing or marking pin can enter into the next hole 28, respectively 29, of drum 20, and the contact arm remains in spacing position as shown in Figs. 8 and 9. Thus, in Fig. 24 the tape space'between b1 and a2 i passes over drum 20. This produces inthe receiver a directiony of currentlow in accordance with which the recorder pen p in Fig. 25 remains in its lowermost position, and thereby produces the line b1 on this tape which is a spacing line between signals. As soon as the vtirst marking hole a 2 in Fig. 24 arrives within the range of the marking pin an, this pin will enter the hole as in Figs. 8 and-9, and will be taken along by the drum tothe left and throw contact arm 55 from the spacing contact onto the marking contact. Since in Fig. 24 no spacing perforation occurs directly underneath the first marking hole a2, the corresponding spacing hole 28 in drum 2O remains covered, and thus the contact arm remains on the marking contact and produces the first line a2 on the receiving tape Fig. 25. Upon arrival-of the first spacing hole b2 in Fig. 24 the device throws the contact arm onto the spacing contact and produces the first spacing line :b2 in Fig-25, and

so on. For instance atv c in Fig. 24 a spacing hole d is right in line with a marking hole c and, therefore, the contact arm 55 will be thrown immediately, after having arrived on' the marking contact, back to the spacing contact and back to the marking and back to the spacingy contact, thereby producing two short dashes 0 with the short intervening space in Fig. 25. y

It should be particularly noted with relspect to the'function ot the contact arm that this arm is not only positively moved between the marking and spacing contacts in,r

accordance with the dictationy of the perforation in the tape, due to the positive action of drum 20 on the marking andvspacing pins, by which alone the tilting of the two sliding

frames

49 and 50 can occur, but the movement of this contact arm, when it does 1 occur, always occurs in absolutely timed relation with the rotation of drum 20. Since this drum is positively geared to the star wheel roller which positively feeds the tape .p as'previously described, and since it is likewise positively geared to the longitudinal motions of the two sliding

frames

49 and 50, the making and the breaking of the contact at M andS is positively and withgreat eX- natural Vibrations or lags of operating elements, such as springs which are used in the prior art type keying heads, can occur.

The contact mechanism for the marking and spacing contacts M and S of which in Figs. 8 to 11 only'fragments are shown, is

constructed as follows.v Referring to' Fig.

2 the contact arm 55 which protrudes beyond the left side of the lever box 12, is surrounded at its outer end bythe contact box 13, the cover of which ispartly broken away in Fig. 2. This box consists of a base plate of insulating material on which are mounted two metal contact blocks 71 and 72 to which the

leads

73 and 74 respectively are connected. These leads are connected to contact pins at the rear of the keying head casing 10 (see Figs. 3 and 4) at which point the leads are connected into the transmitter wiring system such as is shown diagrammatically in Fig. 16. Contact blocks 71 and 72 each carry an adjustable contact screw 75, 7 6 respectively, which is provided with a contact point M and S, respectively', representing the marking and spacing contacts. After the proper spacing adjustment of

screws

75 and 76 with relation to the contact arm has been made, these contact screws are set by means of the clamping screws 77, 78. One of the contact blocks is shown in considerably enlarged horizontal section in Fig. 12. Since as previously de cribed the contact arm 55 lli- Vwhich is held inthe position shown by means of a. comparatively strong spring 7 9 which is positioned in the hollow screw by means of a `plug 8O threaded into the outer end of screw v76.

In order to retain the Contact arm on the Contact on which 1t has been, thrown by the mechanism, and until it is positively removed by the mechanism from this contact, a toggle joint is provided which Aengages the outer end of contact arm 55 as shown in Figs. 2 and 2a. This toggle joint consists of an X-shaped toggle block 81 which engages the edged end of the contact arm at the bottom of one of its grooves as shown in detail in Fig. 2a, the

i .n bottom of the opposite groove of this toggle blockV being engaged by the edged pawl 82 forming the head of a fiat spring 83 mounted on the main casing at 811. The edge of pawl 82 is placed exactly in horizontal alignment with the edged end of -arm when it stands inthe middle position between the two contacts, so that when the arm is thrown onto one or the yother contact, toggle block will snap over the edged end of arm 55 to one or the other side, the pressure of spring 83 eX- .ment of this block.

erted through pawl 82 holding it there with a certain amount of force, until it is positively removed by the operating mechanism. In order to prevent the toggle block 81 from jumping out of position at high speed operation, pa-wl 82 is provided with a. central vertical slot 85 shown in Fig. 2a through which passes a small pin 86 driven into the toggle block 81. This prevents lateral move- In order to avoid an undue exertion of pressure by spring 83 against-arm 55 and thus against the pivotal bearingk of arm 55, this toggle joint may be arranged as shown in Figs. 2b and 2c. In this case leaf spring 83 is replaced by a lever 123 pivotally attached at its lower end to a foot 125 mounted on block 84 mentioned before. Pawl 82 is provided at the other, free end of this lever and eng-ages one side oftoggle block 81,Kwhose other side engages arm 55, the same as in F ig. 2a. In Figs. 2b, 2, however, the spring pressure is exerted diderently. Arm 55 is provided with a transverse pin 12 and pawl 82 with a transverse pin 122, Between the ends of these pins, on each side of the toggle block, is provided a tension spring 121, which Spring pulls pawl 82 toward the end of arm 55 with the toggle block between. The effect is similar to that described with reference to Fig. 2a, provided the edge of pawl y82 is properly placed with respect tothe edge of the armend when the arm is in middle posiL tion. In this case, however, the spring pressure affects only the pawl andthe arm end "i and the toggle block without pressure being exerted against the pivotal bearing of'arm 55.

In order to reduce as much as possible the y mass of all elements moving at highspeed they are perforated wherever feasible. For

instance, contact arm 55 asv shown in Fig. Y

15 is provided with a number of transverse perforations 88, and the two pin guide frames L19 and 50 are provided near the upper end with transverse perforations 89. y

The entire lever gearing contained inbox 12 is constantly splashed with oil, and for this purpose the casing is partly filled with oil as shown at 90 in Fig. 2. In order that the oil may not creep out through the side of box 12 through which the contact arm 55pmtrudes, this arm runs through a splash box 91 which is inserted in the side Wallof 4boxy 12 and which extends partly into the` boxes shown for instance in Figs. 7 and 8. In case oil shouldysplash onto arm 55 insideof the box and tend to run along the arm toward the outside, it must first run into splashboav 91 in which the small drops of oil are readily shaken ofi' bythe rapid oscillations .of arm 55, and they collect at the bottom of the box, whence the cil is drained through hole 92 shown in Fig. 7 back into box 12.

The cover 93 of the lever boX 12 serves at the same time as a support for the pivot pins and shafts extending transversely through this box as shownindetail in Figs. 7 and 8. For instance, main

pivotal shaft

40, 41, 3,8 in

ig. 6 has its outer supportinglmshingY .39 mounted in the box cover 93, this bushing extending sufciently far into the boX to lfold rocking frame 4:2 laterally in place on its pivot. Further, spacing elements 941 and 95 are fastened on cover 93 which serve for supporting the free ends of pivot studs 56 which carry the Contact arm 55 and the interlinliing lever 54. These

spacing elements

94, 95 are each of sufficient length to extend respectiveJlh ly to the contact arm and to the interlinking lever to hold these elements laterally in place on their pivotal aXes.-

It has been stated at the beginning with reference to the description of the tape drive mechanism shown in F igs. 2. 3, 1.11, 17. and v18 Y V31 and 32 apart to remove the stal' wheel roller 23 sufficiently from drum 20`to insert the perforated tape 26, and toproperly bring its central perforations in engagement with the pin teeth of the star wheel, the tape releasebar 101 is provided. This vertical bar is slidingly inserted into and flush with the Vrear wall of box 12 and is provided at its upper end with a roller 102 (shown in large scale in Fig. 6) which stands in alignment with the ends of

arms

31 and 32 which ends, when the tape drive gear is in mesh, surround roller 102 at the bottom. When bar 101 is pulled down the lower ends of

arms

31 and 32 are spread apart as shown in Fig. 18 by which the star wheel gear 22 is thrown fouty of engagement with the driving gear 21 of drum 20, and the star wheel 23 and tape guide roller (Fig. 14) are sufficiently far removed from drum 20 to permit the insertion of the tape from the front of the keying vvdevice in Fig. 2. The number of pin teeth on star wheel roller 23 (Fig. 14) is equal to the number of gear teeth of the roller gear 22, and both are axially in alignment. Likewise, the number of marking and spacing holes on drum 20 is equal to the number of gear teeth of gear 21, and the holes and the teeth are in axial alignment. Thus, when the perforated tape is inserted so that the teeth 24 of the star wheel properly enter the central perforations f of the tape (Fig. 24) the outer rows of perforations' of the tape for marking and spacing will always exactly register with the respective marking and spacing holes on drum 20, as soon as the gears are put back into mesh.

From the previous description of the mechanism, by which the marking and spacing pins are caused to penetrate through the perforations in the tape, it will be noted that at all operating positions of theV pin mechanism at least one of the pins is penetrating a perforation, or if the tape has no perforation there is at least one pin sufficiently tensioned by its spring so that it would penetrate through the tape if a hole were present. It would, therefore, be impossible, notwithstanding the releasing mechanism for the tape drive previously described,l to insert a tape into the lmechanism or withdraw it therefrom. In order to clear the drum and the tape entirely of the marking and spacing pins` when the tape is to be withdrawn or i inserted the following mechanism is provided.

It had been mentioned at the beginning with reference to the description of the pivotal shaft 38. which carries the eccentric 41 (Fig. 6) on which the rocking frame 42 rocks.y

that this shaft is mounted at 40 in the rear wall of the casing. its thinner end 38 protruding through the front of the casing. So long as the eccentric 41 stands in the position shown for instance in Fig. 8, the vertical operating range of sliding

frames

49 and 50` extends far enough upwardly, so as to allow the marking and spacing pins to penetrate into the respective holes of drum 20, Vand to function in the manner described herinbefore. If, however, as shown in Fig. 16 shaft B8 is revolved 180, he eccentric isthrown into its lowermost position, and the vertical operating range of the two guide frames '49 and 50 is lowered suliciently, so that even in the furthest upward position pins s and m remain below the surface of tape bridge 60. Thus, the path for inserting or removing the tape is entirely cleared. In order to throw the tape drive gear into and out of mesh, together with the lowering of the operating range of the spacing and marking pins below the surface of the tape bridge 60 as just described, a pintle 105 is attached to the rear end of pivotal lshaft 40 which engages a slot 106`providedin the enlarged lower end of sliding bar 101 previously described with reference to Figs. 6, 17 and 18. I/Vhen pintle 105 is elevated, shaft 40 stands in the position with eccentric 41 raised, and the tape drive gears are inv mesh, and the entire keying operating mechanism isin operating position as shown in Figs.'8 to 11. As soon as pins s and m are drawn below the surface of tapebridge 60 by throwing eccentric 41 180o down, pintle 105 throwsbar 101 into the position shown in Fig.18 in which the tape drive gears are released. For operating

pivotal shaft

40, 41, 38 in this manner an operating handle 107 (Figs. 2 and 6) is attached to the protruding end of shaft 38, whichV handle is locked by means of a spring controlled pin 108 in its uppermost position shown in these figures, which is the operating position of the device with all gears in mesh. lVhen handle 106 is withdrawn against the pressure of spring 109, pin 107 isdrawn out of its socket and the handle can be swung 180 and the lever be locked in the lower socket 110 in which position the mechanism is cleared for insertion of the tape.-

We claim:

1. In an automatic keying head in combination av movable Contact arm, a positively driven arm operating element, a coupling device adapted to positively 'couple said arm with said operating element, and a tape perforated to represent the signals tobe keyed, and being interposed between said operating element and said coupling device for preventing the arm coupling by said device, except through a perforation in said tape.

2. In an automatic keying head in combination a movable contact arm, a constantly, positively driven arm operating element, a coupling device adapted to positively couple said arm with said operating element, and a tape perforated to represent the signals to he keyed, and being interposed between said operating element and said coupling device for preventing the arm coupling by said device, except through a perforation in said tape. i if 3. In an automatic keying head in combination a movable contact arm, a constantly, positively driven arm operating element, a coupling device adapted to intermittently positively couple saidarm with said operat-` ment and said coupling device for preventing the arm coupling by said device, except through a perforation in said tape.

5. In an automatic keying head in combination a movable contact arm, a constantly, positively driven arm operating element, an oscillating coupling device, positively driven in timed relation to said operating element, and disposed to intermittently positively couple said arm with said operating element, and a tape perforated to represent the signals to be keyed, and being interposed between said operating element and said coupling device for preventing the arm coupling by said device, except through a perforation in said tape.

6. In an automatic keying head in combination, a movable contact arm operably disposed between two abutment contacts, a positively driven arm operating device having means geared to it for positively conveying with said device a tape, perforated to represent the signals to be keyed, and coupling means, positively geared with said arm and adapted to engage said arm operating device, for positively moving said arm in either direction between said contacts, said tape being interposed between said operating device and said couplin@f means to prevent the engagement of said coupling means, except through a perforation in said tape.

7 In an automatic keying head in combination, a movable contact arm operably disposed between two abutment contacts, a positively driven arm operating device having means geared to it for positively conveying with said device a. tape, perforated to represent the signals to be keyed, and coupling means, positively geared with said arm and disposed and operated in timed relation to.

the motion of said operating device, toengage said arm operating device at uniform intervals to cause the positive movement of said arm alternately from one contact tothe other, said tape being interposed between said operating device and said coupling means to prevent the engagement by said cou-r,

pling means, exceptthrough a perforation in said tape.

8. In an automatic keying head in combination, a movable contact arm operably disposed between two abutment contacts, a positively driven arm operating deviceA having means geared to it for positively conveying with said device a tape perforated .to represent the signals to be keyed, and coupling means, positively geared to said arm and including two coupling elements disposed and operable in timed relation to the motion of said operating device to alternately engage said arm operating device ,at uniform-intervals to cause the positive movement of said arm alternately from one contact to the other, saidtape being interposed between said operating device and said coupling means to prevent said elements from engaging said device, except through a perforation in said tape. t 9. In an automatic keying head in combination a pivoted contact arm disposed between two abutment contact-s, a selector drum positively driven at uniform speed, and means geared to said drum for positively conveying in timed relation to the drum motion a ytape perforated to represent the, signals to be keyed, a coupling devicepositively connected to said contact arm and including ytwo re-v ciprocating coupling pins, operable in timed relation to the drum motion, and disposed to. alternately move toward'and away from said drum, said pins being spaced apart in the` direction of the drum axis, said drum having two peripheral rows of suitably spaced holes, one row for each pin, whereby said pins are permitted to alternately` enter a hole of each row to couple the arm with said drum to cause the positive movement of the arm by the drum movement from one Contact to the other during such coupling engagement, said tape being interposed between said drinn and said pins to prevent said pins from entering said drum holes, except when cleared by a perforation in the tape.

l0.. In an automatic keying head in combination a pivotal contact arm disposed betweentwo abutment contacts, a selector drum positively driven at uniformk speed, and means geared to said drum for positively conveying in timed relation to the drum motion Aa tape perforated to represent the signals to be keyed, a coupling device comprising an interlinking pivoted arm coupled at one endin'g two peripheral rows of suitably spaced holes, one row for each'pin, whereby said pins during the :trame reciprocation can alternate'ly enter' a hole of each row to positively f intermittently couple said contact arni with said drum to cause the positive movement of said arm by the drum' motion alternately from one contactto theV other duri-ng such coupling engagement, said tape being inter- :posed between said drum and said pins to y arm, two sliding Jframes one disposed on each of said arms and spaced apart one from the other in the direction of the selectorv drum axis, a reciprocating device geared in timed relation to the drum motion and connected to' said frames to` alternately moveY said fram es toward and away from said drum, a coupling` pin yieldingly disposed at the end of each frame, said drum having two peripheral rows of suitably spaced holes, one row for eachpin,A whereby said pins during the frame recipro'cation can alternately enter a hole of each row to positively intermittently couple said contact arm with said drum to cause the positive movement of said arm. bythe drum motion alternately from one contact to the otherv 'during such coupling engagement, said tape being interposed between said drum and' said pins, to prevent said pins from entering said drum holes except when cleared by :i

. perforation in the tape, said pins yieldingly receding into their respective frame when prevented by the tape from entering a drum hole.

12. In an automatickeying head in comu bination a pivot-ed Contact arm disposed between two abutment contacts, a selector drum positively driven at uniform speed, and means geared to said drum for positively conveying in timed relation to the drum motion 'a tape perforated to represent the signals to be keyed, a eouping device comprising an interlinking pivoted arm coupled at one end with the rear end of said Contact arm,

so that both arms rock in oppositev directions, a sliding block fixed on each arm and a sliding frame on each block disposed to slide toward and away from said drum, a reciprocating device geared intimed. relation to the drum. motion and connected-'to said frames to alternately move the frames. toward Vand away from the drum,qa 'coupling` element at the end of each ltraine adapted to engage said drum during the frame reciprocation l to couple said contact arm with said drum during such engagement for positively moving said arm by the drum motion alternately from one contact to the other, said tape being interposed between said coupling elements and sai-"d drum to prevent said elements trom.

engaging said drum, except through a perforation in said tape.

13. In an automatic keying head iii combination a pivoted contact arm vdisposed between two abutment contacts, a selector druml positively' driven at uniform speed, and

means geared to said drinn for positively con'-A veying in timed relation to the drum motion a tape` perforated to represent the signals to be keyed, a coupling device comprising an interlinking pivoted arm coupled at one end with the' rear end of said contact arm, so that both arms rock inopposite' directions, a sliding block fixed on each arm and a slidi-ng frame on each block disposed to slide toward and away from said drum,a reciprocating device gearedin timed relation to the drum motion and connected to said frames to alternately move' the frames toward and away' from the drum, said frames being spaced apart in vthe direction of the drum axis, a vieldingly disposed coupling pin arranged in the endV of each frame, said drum haviiiga pel rip'heial row of holes for each pin, spaced apart in each row the shortest distancebe-` tween adjacent holes occurring in the tape,

whereby said pins can alternately enter ahole of each row during' the frame reciprocation to intermittently positivelycou-ple said contact arm 'with said druni toy cause the positive rocking of said arm through the pins by the drum motion alternately from one Contact tov the other during suoli coupling engagement, said tape being. interposed between said. drum and said pins to prevent sind pins from entering said drum holes, except when cleared by a perforation in the tape.

14t- In an automatic keying head 'in combination a Vpivoted contact arm disposed be-A tween two abutment contacts, a selector drum positively driven atuniform speed,and`means geared to said drum for positively conveying in time-d relation tothe drum motion a tape perforated to represent the signals to be' keyed, aV coupling device comprising an interlinkingy pivoted arm coupled at one end with the rear end of said contact arm, so that both arms rock in opposite directions, a sliding block fixed on each arm and a sliding frame on each block disposed to slide toward 'and' away from' said drum, a reciprocating device geared in timed relation to the drum motionl and connected to'l said frames to alternat'ely movethe'frames toward and away from the" drum, said frames being spaced apart in the direction of the drum anis, a yieldingly disposed coupling pin arranged'iii the end of't each frame, said drum having a peripheral row of holes for each pin, spaced apart in each row the shortest distance between adj acent holes voccurring in the tape, said frames and pins being inclined towards one another at their ends, the drum holes for Vthe pin, whichA is inclined towards the direction of drum rotation, being inclined toward that direction, the holes'for the pin, which is 'iiiclined against the drum rotation extending substantially in .radial direction, whereby each of said pins can alternately with the other freely pass into an encountered hole of its 'row to the hole bott-oni during the frame. reciprocation, to be taken along by the hole Wall, and to thereby7 positively rocikv said contact arm through the drum motion from one contact to the other, said tape being interposed between said drum and said pins to prevent said pins from entering said drum holes. except when cleared by a perforation in the tape.

15. In a lever systeni, pivotally mounted to Y oscillate between two abutments, a toggle element supported at one of its points at a point of said system which partakes in the oscillation, and a yielding element disposedto support said toggle element at another point and to exert a pressure against said element toward its othersupporting point in the direction of a line extending between said supporting points when the system is positioned intermediate its abutments, whereby said toggle element is held between its supports in -an unstable equilibrium, tending to throw and hold said system either against one or the other of said abutments.

16. In a lever system a lever arm, pivotally mounted to oscillate between two abutments,

a toggle element supported at one of its points at the end of said arm, and a spring pressed pawl having its end disposed to support said toggle element at another point and to exert a pressure against said element toward its other supporting point in the direction of a line extending between said supporting points when the arm is positioned intermediate its abutments, whereby said toggle element is held between its supports in an unstable equilibrium, tending to throw and hold said arm either against one or the other of said abutments.

17. A keying head having oppositely disposed abutment contacts, a Contact arm, and means for moving said arm alternately onto said contacts at suitable intervals, and means for holding said arm on either contact during said intervals, comprising a pawl provided with an edged head and having the edge disposed opposite to and in line with the similarly edged end of the arm, when the arm is in a position intermediate said contacts, a toggle block grooved on opposite sides and interposed at its grooved portions between said two edges, a spring disposed to to said contacts atsuitable intervals, and

means for holding said arm on either conn tact during said intervals, comprising a pawl l provided with an edged head and havingthe edge disposed opposite to andin line withv the'similarly edged e-nd of thearm, when the arm is ina position intermediate said contacts, a toggle block grooved on opposite sides and interposed at its grooved portions between said two edges, a spring disposed -to press said pawl and toggle block toward the" arm end, whereby said block is held in an un-A stable equilibrium between the two edges and, through the spring pressure, tends to hold the arm on the contact, against which it has been thrown by said moving means, and means for holding said blockm of said edges. i l

19. In an automatic keying head in 'combination, a movable contact arm operably dis-V posed between two abutment contacts, a positively driveny arm operating device havingv means geared to it for positively conveying with said device a tape, perforated to represent the signals to be keyed, and couplingV means, positively geared withsaid arm and adapted to engage said arm operating device, for positively moving said arm in either di-' rection between said contacts,said tape being interposed between said operating device and said coupling means to prevent the engagef` ment of saidl coupling means, except through av perforation in said tape,'each of said abutment contacts having al cushioned contact' point to prevent the rebound of said contact arm. l v j 20. In an automatic keying head in combination two abutment contacts and apivoted Contact arm disposed and movable therebetween, a selector drum having a pluralityof recesses on its periphery and being Vpositively driven at uniform speed, a tape'feed' positively geared to said drum and adapted to convey over rsaid drum a tape perforated to represent the signals vto be keyed, a reciprocating coupling device connected'with said arm and having coupling pins adapted to alternately engage the drum recesses throughtlie tape perforations for coupling the arm intermittently with said drum toy movethe arm from one contact to theother in' accord ance withthe occurrence of the tape perforations, and a rotatable pivotal shaft havingan eccentric serving as a pivot for said-rel ciprocating coupling-whereby through the rotation ofthe eccentric said reciprocating position longitudinally coupling may be raised and lowered to move said pins into and out of operating range with said drum recesses, means for hand operating said pivotal shaft, and means operatively connected with said pivotal shaft for simultaneously removing said tape feed from said drum to clear said drum for insertion and removal of the perforated tape. l

21. In a keying head of the character described, in combination a contacting mechanism, a rotating selector drum, a coupling mechanism between said drum and said contactingmechanism for putting the contacting mechanism under the .control of saidfdrum, and a tape drive for feeding a perforated tape over the peripheryV of said drum to control said coupling through the tape perforations, said tape drive comprising two pivoted arms, disposed with their ends adjacent to said drum and on opposite sides of the drum axis, one arm carrying near its end'a tape drive roller and its driving pinion, the other arm carrying near its end a tape guide roller, a gear wheel on said drum engageable with said roller drive pinion to feed said tape positively and in timed relation with the drum speed over said drum, means for normally forcing the free arm ends towards one another to hold said tape feed roller and said guide roller in engagement with said drum, and hand controlled means for spreading said arms apart to clear said drum from the tape feed and from the guide roller to permit the insertion and the removal of the tape.

22. In aleying head of the character described, in combination a contacting mechanism, a rotating selector drum, a coupling mechanism between said drumfand said contacting mechanism for putting the contacting mechanism under the control of said drum, and. a tape drive for feeding a perfo-V rated tape over the periphery of said drum to control said coupling through the tape perforations, said tape drive comprising two pivoted arms, disposed with their ends adjacent to said drum and on opposite sides of the drum' axis,- one arm carrying near its end a tape drive roller and its drivingpinion, the other arm carrying near its end a tape guide roller, a gear wheel on said drum engageable with said roller drive pinion to feed said tape positively and in timed relation with the drum speed over said drum, a tension spring Y for' normally forcing the free arm ends -towards one another to hold said tape feed roller and said guide roller in engagement with said drum, and a Cam roller disposed midway above said arm ends, and hand controlled. means for moving said cam roller against said cam ends to spread the arms apart to clear said drum from the tape feed and from the guide roller to permit the insertion and removal of thetape.

23. Inv a. keying head ofthe character described, in combination a contacting mechanism, a rotatingy selector 'drum, a vcmlpliiig mechanism betweensaid drum and saidcontacting mechanism for putting tire contacting mechanism under the control of ysaid drum, and a tape drive for feeding al perforated tape over the periphery of said drum to control saidY coupling throughV the tape perforations, said tape drive comprising two pivoted arms, disposed with'their'endsadjacent to said drum and on opposite sides of the drum axis, one arm 'carrying near its end a tape drive roller and .its driving pinion, the other arm carrying near its end a tapeguide roller, a gear wheel on said drum `engageable with said roller drive pinion to-feed said tape positively and in timed relation with the drum speedl over' said drum, means for normally forcing the free arm endsvtowards one another to hold said tape feed' roller and said guide roller-in engagement with said drum, andhand controlled means for spreading said arms apart to clear said' drum fromthe tape' feed and from the guide roller to permit the insertion and the removal of the tape, and means operated by the same hand control-led means for simultaneously removing said coupling mechanism' outnof coupling range with said drum to clear the drum also from said coupling mechanism for the insertion and removal of the tape.

Y FRANK KUNG. .ERNEST KNOPP.