US2228716A

US2228716A - Printing telegraph apparatus

Info

Publication number: US2228716A
Application number: US118525A
Authority: US
Inventors: Walter J Zenner
Original assignee: Teletype Corp
Current assignee: AT&T Teletype Corp
Priority date: 1936-12-31
Filing date: 1936-12-31
Publication date: 1941-01-14
Anticipated expiration: 1958-01-14
Also published as: US2294436A; FR825419A; US2238090A

Description

Jan. 14, 1941. w, ZEQNER 2,228,716

PRINTING TELEGRAPH APPARATUS Filed Dec. 51 1936 2 Sheets-Sheet 1 HHHH INVENTOR WALTER J. ZENNER Jan. 14, 1941. 2 w, J. ZENNER 2,228,716

PRINTING TELEGRAPH APPARATUS Filed Dec. 51, 1956 2 Sheets-Sheet 2 zsg 98 I36 FIG.8

INVENTOR 57 WALTER J. ZENNER A'r'roR EY Patented Jan. 14, 1941 UNITED STATES Y 2,228,716 PRINTING TELEGRAPH APPARATUS Walter J. Zenner, Des

Teletype Corporation, tion of Delaware Plaines, Ill., assignor to Chicago, Ill., a. corpora- Application December 31, 1936, Serial No. 118,525

12 Claims.

This invention relates to printing telegraph apparatus, and particularly to selector mechanisms for controlling the operation of such apparatus.

An object of the invention is the provision of instrumentalities in a selector mechanism for easy, quick, and accurate adjustment of its elements for efficient operation.

Another feature of the invention is to provide a selector mechanism'of the assisted armature type in which the armature assisting lever is at all times free to engage the element by which it is operated.

Another object of the invention is to provide a selector mechanism in which the energy developed by the selector magnet is minimized.

A feature of the invention is to provide a universally adjustable mounting 'for the selector magnet of a selector mechanism.

Another feature of the invention is to provide completely resilient interconnection between the armature assisting lever and the selector lever in a selector mechanism.

The invention contemplates numerous other features capable of incorporation into selector 25 mechanisms in various combinations.

For a full and complete understanding of selector mechanisms of the type to which the several features of the invention may be applicable, reference may be had to Patent No. 1,937,376 granted November 28, 1933 to Walter J. Zenner.

Briefly, the invention contemplates, in accordance with one embodiment thereof, a pivotal mounting for the magnet of a selector unit to vary the clearance between the magnet and its armature without altering the relationship between the armature and other elements of the selector mechanism. Such pivotal mounting may be fixed or movable, and if movable, may permit adjustment of the armature with respect to other elements of the selector unit independently of the adjustment of the relationship between the magnet and its armature.

In another of its embodiments, the invention contemplates the armature of a selector magnet may be detached and dissociated from the armature assisting lever, and may instead be applied to a latch which has a shoulder to engage a lug formed on the flutter lever or may be applied directly to a selector. lever which is movable under the control of the flutter-lever.

For a complete understanding of the invention, reference may be had to the following detailed description, taken in connection with the accompanying drawings in which Fig. 1 is a plan view, partly in section, of a selector mechanism showing magnet adjusting means in accordance with one embodiment of the invention;

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

Fig. 3 isa vertical sectional view taken substantially on the line 33 of Fig, 1;

Fig. 4 is a fragmentary plan view showing a modified magnet adjusting system;

Fig. 5 is a. vertical sectional view taken substantially on the line 5-5 of Fig. 4;

Fig. 6 is a fragmentary plan view showing another form of magnet adjusting system;

Fig. 7 is a vertical sectional View taken on the line 1-1 of Fig. 6 Fig. 8 is a plan view showing a selector mechanism in which the selector magnet controls a latch;

Fig. 9 is a verticalsectional view taken on the line 9--9 of Fig. 8;

} Fig. 10 is a fragmentary elevational view of the selector mechanism of Fig. 8 as seen from the upper edge thereof;

Fig. 11 is a fragmentary plan view showing a selector mechanism in which periodic movement 25 of the flutter lever is not affected by the operation of the magnet armature; and

Fig. 12 is a vertical sectional view taken on the line l2-l2 of Fig. 11.

Referring now to the drawings in which identi- 30 I cal reference characters designate corresponding parts throughout the several views, and particularly to Figs. 1 and 2, reference numeral 2| designates a mounting plate for a selector mechanism for printing telegraph apparatus. magnet assembly indicated generally by the reference numeral 22 comprises a bracket 23 to l which is secured, by means of screws 24, a magnet core 26. Core 26 has twoarms, each of which supports a winding 21 which is adapted to be con- 40 nected to atelegraph line. At their outer ends the arms of core 26 terminate in pole faces 28.

Bracket 23 supports opposed pivot screws 29, which in turn pivotally support an armature lever indicated generally by the reference numeral 3| 45 and. comprising

arms

32 and 33. Arm 32 has rigidly secured thereto magnet armature 34 which terminates in alignment with pole faces 28. The outer end of arm 33. terminates in cam follower portion 36. I

The lower most of pivot screws 29 is supported in a boss 3!] which is integral with bracket 23 and extends through a a closes fitting aperture in mounting plate 2! to serve as a pivotal mounting for the bracket. The bracket is provided at a 5 A selector 35 I friction clutch assemblies.

point spaced from pivotal mounting screw 29 with an open slot 31, having parallel sides, and in which is disposed head 38 of an adjusting screw which has the shank 39 eccentric with respect to head 38. Bracket 23 is provided with a plurality of clearance holes 4| which may be arcuate on radii originating on the axis of boss 38, and in which are disposed clamping screws 42 threadedly engaging mounting plate 2 Cam follower portion 36 of armature lever 3| is disposed in operative alignment with an armature cam 43 included in a selector cam assembly, indicated generally by the reference numeral 44, mounted on power driven shaft 46 extending through mounting plate 2|. Cam assembly 44 is arranged to be driven from shaft 46 through discs 41 fixed to shaft 48, resilient discs 48 in frictional engagement with discs 41 and discs 49 fixed to cam assembly 44 and in frictional engagement with discs 98.

Discs

41, 48, and 49 constitute Selector cam assembly 44 includes a stop arm 5| which is arranged to be arrested and released for rotation alternatively under the control of a stop gate 52 included in a stop gate assembly 59. Stop gate assembly 59 has as its foundation a plate 53 which is pivoted below a plate 55 by means of pivot screws 54 carried by plate 55 which is supported by posts 56 mounted on mounting plate 2 I. An arm 51 mounted on pivot screw '54 above plate 55 has extending therethrough the shank of a knurled-headed screw 58 which threadedly engages stop gate mounting plate 53. Plate 53 may be adjusted pivotally about pivot screw 54 and may be clamped in any desired position of adjustment by drawing plate 53 and arm 51 into clamping engagement with plate 55 by means of screw 58.

Stop gate 52 is pivotally mounted on stud 59 carried by plate 53, and is biased clockwise by a tension spring 69. The stop gate has a portion disposed in the path of stop arm 5|, when in extreme clockwise position, and it may be latched in that position by shouldered latch lever 6|. Lever 6| is pivotally mounted on the under side of plate 53 and is urged by spring 62 into latching engagement with stop gate 52. Latch lever 8| is rocked against the resistance of compression spring 82 to lift its shoulder out of latching engagement with the stop gate-by a plunger pin 83 in the operating path of which is disposed one arm of a bell crank 84, the other arm of which engages latch lever 8|. A plunger operating screw 65 carried by extension 350i armature lever arm 33 in alignment with plunger pin 63 shifts the pin to effect the release of the stop gate when the armature lever is in its extreme clockwise position, at which time armature 34 is out of engagement with pole face 28. Plunger pin 63 is retracted by spring 82 and permits latching lever 8| to latch stop gate 52 when armature lever 3| is in its extreme counterclockwise position, at which time armature 34 engages pole face 28.

A selector lever assembly,.generally indicated by the reference numeral 88, is supported by mounting plate 2| and comprises a mounting bracket 61 secured to mounting plate 2| by screws 68, and a selector lever 69 pivotally supported by bracket 61 by means of pivot screws 1|. A tension spring 12 has one end connected to selector lever 89 and the other end secured to extension 35 of armature lever arm 33. Said extension also carries an abutment screw 13 which is adjustable with respect thereto, and the head of which abuts selector lever 89 intermediate its ends. At its free end, which is the right-hand end as viewed in Fig. 1, selector lever 69 is provided with spaced depending arms 14, by means of which the setting of selector elements of a sword and T-lever selector assembly is controlled.

The sword and T-lever assembly is designated generally by the reference numeral 18, and comprises a plurality of thin, flat selector fingers, or sword levers 11, and an equal number of T- levers 18 individually aligned with the sword levers 11. Sword levers 11 are individually supported by spacer plates 19 which also separate the T-levers 18 and which are mounted on studs 8|, and are spaced apart by washers 82. Each of the sword levers 11 has at its left-hand end, as viewed in Fig. 1, a disc-like portion 83 which is fitted into a correspondingly shaped aperture in a sword operating bell crank lever 84 pivotally mounted on pivot pin 86. Each of the bell crank levers 84 is arranged to be rocked counterclockwise by one of a plurality of cam projections 81 carried by the cam assembly 44 in helical arrangement. Adjacent to the disc-like portion 83 each sword lever 11 is provided with oppositely extending arms 88 which terminate in abutments 89.

T-levers 18 are rotatably mounted upon pivot pin 9| carried by mounting plate 2| and each of the levers 18 is provided with an arm 92 which (:1

terminates in a disc-like portion 93. T-levers 18 are intended to be articulated, by means of the disc-like portions 93, to code bars, code discs, or other permutation code elements (not shown) as disclosed in Patent 1,745,633 granted February 5" 4, 1930, to S. Morton et a1.

Pivot pin 86, in addition to supporting sword lever operating bell cranks 84, also pivotally supports a locking bell crank lever 98 which'has one arm 91 terminating in a cam follower portion lo which engages a locking cam 98, included in cam assembly 44, and has another arm 99 terminating in a locking blade |9l adjacent to which selector 58 is provided with a locking lug I92.

reciprocated leftwardly by associated bell cranks 84, and such angular movement of selector lever 69 is sufficient to bring locking lug I92 from one side to the other of locking blade |9|. Continued reciprocation of a sword lever, after one of its abutments 89 has engaged one of the depending arms 14 of selector lever 69, causes the sword lever to move angularly about the center of its disc-like portion to bring its free end into engagement with its associated T-levers 18 at either side of the pivotal mounting 9| thereof. The angular movement of sword levers 18 is limited by stop pins 183 carried by mounting plate 2|. Tension springs I95 and I81 bias armature lever 3| and sword lever bell cranks 84 respectively in clockwise direction, and tension spring |98 biases locking bell crank lever counterclockwise. The selector mechanism shown in Figs. 1 and 2 is adapted to be controlled by permutation code signals comprising marking and spacing impulses V in various combinations received by the selector magnet winding 21 from the telegraph line to face 28, and abutment screw 65 is drawn away 44 rotates through one revolution during the reception of a code combination, and, in rotating, cam 43 rocks armature lever 3| counterclockwise, cam 98 unlocks selector lever 69, these operations occurring periodically, and cam projections 81 rock sword lever bell cranks 84 counterclockwise. All of these operations occur in timed relation to the reception of code signal impulses. If the selector magnet is energized at the instant armature cam 43 actuates armature lever 3| to bring armature 34 into engagement with pole face 28, the armature will be held and armature lever 3| will be held in its extreme counterclockwise position, whereby abutment screw 13 will be drawn away from selector lever 69. Upon the unlocking of selector lever 69, tension spring 12 will cause the lever to be rotated to its extreme counterclockwise position, whereby one of the arms 14 will be presented to an abutment 89 of a particular sword lever H in accordance with the energized condition of the selector magnet. When the selector magnet is deenergized at a time that armature 34 is brought into engagement with pole face 28 by armature cam 43, the armature will not be held, and the selector lever, when unlocked, will be positioned in accordance with the deenergized condition of the selector magnet.

A code signal combination concludes with a stop impulse which is represented by the energized condition of the selector magnet. The armature is thusheld, and armature lever 3| is retained in its extreme counterclockwise position, whereby plunger pin 63 is permitted to be retracted, and stop gate 52 locked. It follows from this that cam assembly 44 is arrested at the conclusion of one revolution and awaits release by the start impulse of the next code signal combination.

The feature of the invention disclosed inFigs. l and 2 is the arrangement for adjusting the selector magnet represented by boss thirty, slot 31, eccentric screw head 38, and arcuate clamping screw holes 4|. With screws 42 loosened, bracket 23 may be rotated through a small angle about the axis of boss 38 by rotating eccentric screw head 38. The result of such adjustment is to vary the clearance between selector magnet pole face 28 and armature 34. The relationship between armature lever arm 33 and armature cam 43 is not altered by such adjustment of the magnet armature clearance because of the fact that the armature lever -3| is pivoted upon the same axis as is bracket 23. Thus the adjustment afforded by the slot 3! and eccentric screw head 38 is confined to the desired point, and no other portion of the selector mechanism is affected.

Figs. 4 and 5 disclose a somewhat different arrangement for varying the space between a selector magnetarmature and its pole face. Certain portions of the apparatus shown in Figs. 4 and 5 are identical with portions of the apparatus shown in Figs. 1 and 2, and are identified by the same reference numerals.

Figs. 4 and 5 are fragmentary views and disfied arrangement.

close only those portions of a selector mechanism which need be shown to indicate the modi- Except for the modification, the selector mechanism having cooperation with the elements shown in Figs. 4 and 5 may be identical with the mechanisms shown in Figs. 1'

and 2. Referring specifically to Figs. 4 and 5,

reference numeral 2| identifies selector mounting plate as in Figs. 1 and 2. Mounting plate 2| supports a selector magnet assembly, identified generally by the reference numeral Ill, and comprising a bracket 2 to which magnet core H3 is secured by means of screws '||4,. Core ||3 hastwo arms, each of which supports a helical winding 6 and terminates in a pole face H5. Bracket ||2 pivotally supports armature lever 3| by means of pivot screws similarly to the manner in which bracket 23 (Fig. 1) supports armature lever 3|. The lower pivot screw does not extend through the mounting plate 2|, and bracket 2 is not pivotally mounted on the axis of rotation of armature lever 3| as is bracket 23 in Fig. l. Bracket H2 is pivoted to plate 2| by means of pivot screw ||8, which,

passes through an aperture in bracket 2 at a point remote from the pivot screws andsubstantially on a line passing through the cam follower portion 36 offlutter lever 3| and the axis of pivot screws I ll.

Adjacent to the lower pivot screws casting H2 is provided with an open slot 9 in which is disposed a head 2| of an adjusting screw, the shank I22 of which is eccentric to the head |2| and passes through mounting plate 2|. All other parts of the selector mechanism may be identical with corresponding elements shown in Fig. l, and certain of these elements, such as selector lever assembly 65 and armature lever assembly 3|, are specifically identified by reference characters.

In the structure shownin Fig. 4, rotation of eccentric screw head |2| causes selector magnet bracket I I2 to move through a small angle about screw,| |8 as a pivot so that the axis of rotation of armature lever 3| shifts through an are which crosses the line defined by cam follower terminal portion 38 of arm' 33 of armature lever 3| and pivot screw H8. The space between armature 34 and pole face ||5 may thus be varied, and in the making of such adjustment the relationship between armature lever 3| and the armature cam is not materially altered, due to the fact that the rocking of armature lever 3| about its point of engagement with the armature cam, as the position of bracket 2 is adjusted, is only very slight.

Attention is now directed to Figs. 6 and 7, in which is shown a modification of the structure of Fig. 1, by means of which the relationship between the armature lever and the armature cam may be varied Without interfering with a predetermined, previously established adjustment of the armature with respect to its pole face. It will be noted that the selector magnet assembly 22 is identicalwith that shown in Fig. 1 with the single exception that the clearance holes now designated by the reference numeral I26, through which the clamping screws 42 extend, are not arcuate to provide rotational movement only of selector magnet bracket 23, but 7 are instead of sufiicient size to permit the bracket to be moved in all directions. The boss for defining rotation ofthe magnet bracket, identified in this figure by reference numeral I21, is not retained in mounting plate 2|, as in Fig. 2, but

.extends through a clearance hole I28 in plate 2| and engages an arm I29 positioned below mounting plate 2| and pivoted to the mounting plate by means of pivot screw I3I. At its opposite end thearm I29 terminates below a circular aperture I30 in mounting plate 2 I, and has formed in the end thereof an open recess I32. Arm I29 may be moved angularly about its pivotal mounting I3I by inserting into the circular aperture above recess I32 an implement I33 having a cylindrical portion dimensioned to enter and be rotationally guided within aperture I30, and having an eccentric projection I34 which enters recess I32 in arm I 29. By rotating the implement, angular movement is imparted to arm I29, which causes the pivotal mounting I21 ofmag-net bracket 23 and armature lever 3I to move in an arc, the radius of which is the distance from the axis of boss I21 to that of screw jI3l. Cam follower portion 36 of armature lever 3I is thus shifted I selector mechanism shown in Figs. 1 and. 2', in

which the selector magnet armature, instead of being rigidly connected to the armature assisting lever, is connected to a latch which cooperates with the armature assisting lever to hold it in position corresponding to a selective condition, which is represented by the energized condition of the selector magnet. It may be noted, in connection with the structure shown in Fig. 1, that the position of the armature lever 3I determines the position of selector lever 69 when that lever is unlocked, and that the tension spring I06 must be of sufficient strength to move armature lever 3| and selector lever 69 totheir extreme clockwise positions when the armature 34 is not attracted by the selector magnet, and the armature lever is not moved out of itsextreme clockwise position by the armature cam. When armature 34 is to be held by the magnetic attraction of core 26, the attractive force must be greater than the tension of spring I06, and the energizing current must be of sufficient magnitude to' provide the necessary attraction. In the structure shown in Figs. 8 and 9, the armature assisting lever spring may be considerably lighter than the one required in the selector mechanism shown in Figs. 1 and 2 because the selector magnet is not required to overcome the tension of that spring. As indicated in Figs. 8 and 9, selector magnet assembly 22, sword and T-lever assembly I6, and adjustable stop gate assembly 50, identical with corresponding assemblies previously designated in connection with Fig. 1, are mounted on mounting plate I36. Also, power-driven shaft 46 extends through an aperture in mounting plate I36 and. supports selector cam assembly 44 arranged to be frictionally driven thereby. Selector lever 69 is pivotally mounted on a bracket I31 of which no details of construction are shown, but which may, if desired, take the form of an adjustable bracket such as that disclosed in copending application of E. W. F. Hanke, Serial No. 116,271 filed December 17, 1936. Cam-operated locking bell crank 96 is pivotally mounted upon pivot pin 96, as are also sword lever operating bell cranks 84. Bracket 23 of the selector magnet assembly has opposed pivot screws I38 which pivotally support a bell crank lever I39, one arm of which carries selector magnet armature I4 I ,andthe other arm of which terminates in a latching shoulder I42. Armature assisting llever I23 is mounted for pivotal movement by -pivotscrews I44 on a bracket I40 which maybe similar to bracket I31. Armature assisting lever 5 I 43 has a portion abutting yieldable spring member I45 .carried'byarmature I4I. Alug' I46 is adapted to be engaged by shoulder I42 of .bell

crank I39, and the .lever I43 also hasacam follower portion I4I. Tension spring I48 biases armature assisting lever .I 43 in clockwisedirection. Tension spring 12and abutment screw I3 constitute interconnection between armature assisting lever I43 and selector lever.69,as.in the structure shown in Fig. -1. A lighttensionspring I50 biases bell crank lever I39 in counterclockwisedirection, whereby it tends to be withdrawn from latching engagement .with lug I46of selector lever ,I43,.and armature -I4I tends to be retracted from its pole face.

In operation, armature assistinglever I43 isperi- .odically rocked counterclockwise by armaturecam 43, whereby the lever engages yieldable spring member I45 and forces armature ,I4I into engagement with its pole .face, .and latch shoulder I42 into latching engagement with lug I46. If armature I4! is not then held due to energized condition of the selector magnet, spring 148 disables latching bell crank I39, and armature assisting lever I43 returns toitsextremeclockwiseposition before selector lever .69 is unlocked by bell crank 96 actuated by cam 98. If, however, the selector magnet is energized and holds its armature I4I, armature assisting lever I43 ,will be latched up and prevented from immediately returning to its extreme clockwise position, and when the selector lever 69 is unlocked'by its locking bell crank 96, it will be drawn to its extreme counterclockwise position by spring 12 to effect a setting of one of the sword levers 1-1 in accordance with the energized 40 condition of selector magnet winding 21. Winding 21 is required to carry only suflicient energizing current to cause armature I4'I to be held in opposition to tension spring I50. None of the stored energy of armature assisting lever restoration spring I48 is operative upon armature I4I, but is instead resisted by latching shoulder I42 which has positive blocking relation to latching 'lug I46 until the selector magnet releases its armature. With the arrangement shown in Figs) 8 and 9 a much lower current value may be employed for operating the selector magnet than in the arrangement shown in previously described Fig. 1.

In Figs. 8 and 10 there isshown an arrangement for varying the air gap between the selector magnet pole faces 28 and armature I4I which is related to but differs from the arrangement shown in Figs. 1 and 2, and which constitutes the preferred construction. It will be noted, by reference to Fig. 9, that magnet bracket 23 has a depending boss I which, in addition to mounting the lower pivot .screw I38 for the latching bell crank I39, also establishes a center of rotation for selector magnet bracket 23, in the same manner that boss 30 (Fig. 1) constitutes a pivot for the selector magnet bracket shown in Fig. 1. The selector magnet bracket 23 (Fig. 8) is provided with arcuate apertures 4|, the arcs of which have their centers on the axis of pivot screw I38, and through which extend clamping screws 42 to threadedly engage mounting plate I35. At a point remote from pivot screw I38, and corresponding to the location of open, parallel-sided slot 31 (Fig. 1) bracket 23 (Figs. 8 and 10) threadedly supports the shank of an adjusting screw I49 which is provided with head I66, and, spaced therefrom along the shank, flange I61. A stud I68 is rigidly secured to mounting plate I36, and extends up- 5 wardly into the space between head I66 and flange I61. Screw head I66 may be provided with the usual slot (not shown) for cooperation with a screw driver, and there may be provided in the periphery of the head, sockets I69 into which a pin may be inserted for rotation of screw I49 in the manner in which capstans are rotated. The sockets I69 permit rotation of screw I49 by suitable implement when the installation of the selector mechanism is such as to prevent access to the slotted head by a screw driver.

It will be apparent that when screw I49 is rotated, it can undergo no axial movement, due to the confining action of head I66 and flange I6'I upon stud I68. Since screw I49 threadedly engages bracket 23, the latter must move toward or away from stud I68 as the screw is rotated, and in so moving it pivots about screw I38 and varies the air gap between pole faces 28 and armature I4l. Although there is no specific showing in the drawings, attention is directed tothe fact that the magnet adjustment afforded by screw I49 and stud I68 may be substituted for the air gap adjusting system comprising slot 31 and screw 38 in the embodiment of the invention shown in Figs. 6 and 7. In that embodiment, the magnet bracket 23 is arranged to undergo rectilinear movement as well as pivotal movement, as previously described, and the open slot 3'! permits 35 the rectilinear movement. Should screw I49 and stud I68 be substituted for screw 38 and slot 31 in Fig. 6, bracket 23 would be as free to move rectilinearly as in the present showing, and during such movement, the shank of screw I49 40 would be shifted with respect to stud I68 in the direction of movement of bracket 23 rectilinearly, there being no opposition exerted by stud I68 to movement of screw I49 rectilinearly.

Another modification of the invention, in which a still diiferent relationship between armature assisting lever, selector lever, and magnet armature exists, is shown in Fig. 11. Referring now to that figure, itwill be noted that a selector mounting plate I5I supports a selector magnet 50 assembly 22 and brackets I64 and I52 on which selector lever I53 and armature assisting lever I56 are respectively pivotally mounted by means of pivot screws I54 and I5! respectively. The brackets I52 and I64 may be similar to brack- 55 ets I35 and I46, and may be adjustable in the same manner that they may be made adjustable. The bracket I64 which mounts the armature supporting lever may, if desired, be a part of the magnet bracket in the same manner that armature supporting levers 3| and I39 shown in Figs. 1 or 4 and 8 respectively are mounted on portions of the selector magnet bracket. Armature assisting lever I56 is urged into extreme clockwise position by tensioning spring I55 and is periodically rocked counterclockwise by armature cam 43 included in selector cam assembly 44 carried by power-driven shaft 46. The armature of the selector magnet is designated I58 and is mounted directly on selector lever I53, which has, at its free end, locking lug I02 similar to that employed on selector lever 69 (Fig. 1) with which there cooperates locking bell crank lever 96. Since selector lever I53 carries the selector magnet armature I58, the tripping ofthe 7 stop gate for the selector cam assembly 44 in response to a start impulse must be under the control of that lever. Accordingly, lever I53 is provided with an arm III having abutment screw I12 in operative alignment with stop gate latch tripping plunger pin 63 of adjustable stop gate 5 assembly 50.

The interconnection between selector lever I53 and armature assisting lever I56 is shown in detail in Fig. 12 by reference to which it will be observed that" selector lever I53 is provided with 10 spaced depending arms I59 in alignment with which are depending arms I6I of armature assisting lever I56 spaced apart a greater distance than are the arms I59. The arms I59 of armature assisting lever I53 are apertured to receive shoul- 15 dered pins I62, which are urged in opposite directions by compression spring I63 to force their shoulders into abutting relation with the inner surfaces of arms I59. With the arrangement shown in Fig. 9, selector lever I 53 tends to be cen- 20 tered with respect to armature assisting lever I56, and if the latter is moved angularly, an unbalance is created in the combination of pins I62 and spring I63 which causes the selector lever I53 to be moved in a direction to eliminate the unbal- 25 ance when it is unlocked by locking bell crank 96.

It will be observed that the interconnection between armatur assisting lever I56'and. selector lever I53 is resilient or permissive in both directions, as contrasted Withinterconnections pre- 30 viously described, comprising a tension spring and an abutment screw, the combination of which affords a permissive or resilient interconnection in one direction, and a positive interconnection in the other'direction. 35

In the operation of a selector mechanism, as disclosed in Fig. 11, it will be presumed that the energizing current of the selector magnet is sulficient to hold selectorlever I53 in opposition to a condition of unbalance in the spring interconnec- 40 tion between selector lever and the flutter lever, but is insufficient to attract the selecto-r'lever from its extreme clockwise toextreme counterclockwise position. Due to the periodic rocking of armature assisting lever I56 counterclockwise 45 by cam 43, an unbalance, tending to rotate selector lever I53 counterclockwise, will be establishedin the interconnecting pins I62 and spring I63, and when locking bell crank 96 is actuated by cam 98 to, unlock selector lever I53, the latter 50 will be rotated to bring armature I58 into engagement with the pole face of the selector magnet. If that magnet is then energized, the selector lever I53 will be held in its extreme counterclockwise position after the armature assist- 55 ing lever has returned to its extreme clockwise position due to escapement of its cam follower portion from an apex of flutter cam 43, and a selective condition corresponding to a marking signal is thus established, whereupon locking bell 60.,

crank cam 98 permits locking bell crank 96 to lock lever I53.

If instead of being energized at the time the armature assisting lever I56 is rotated counterclockwise, selector magnet should be deenergized, 55 in response to a spacing signal, the selector lever I53 will not be held and will return to its extreme clockwise position when the armature assisting lever returns to its extreme clockwise position, whereupon the selector lever may be locked in 70 thatposition, which corresponds to a spacing signal condition of the selector magnet.

.With the arrangement shown in Figs. 11 and 12, the selector magnet armature is not asso -ciated with the armature assisting lever, as in the 15 previously described structures, butis associated with the selector lever.- The selector magnet is not called upon to actuate selector lever I53, but is only required to hold it in opposition to a relatively weak unbalance in the centering spring mechanism when the armature lever returns to its extreme clockwise position. The restoring spring for the armature assisting lever may thus be as heavy as desired. Furthermore, the armature assisting lever is never held out of engagement with the armature cam, as it may be in the structureshown in Fig. 1, by armature 28 and in Fig. 6 by latch lever 139, but is instead continuously responsive in its movements to the contour of the armature cam.

What is claimed is:

1. In a selector mechanism, an electromagnet, a pivotal mounting therefor, a rotatable cam, a lever pivoted coaxially with the pivotal mounting of said electromagnet and having a portion engageable with said cam, an armature for said electromagnet carried by said lever, and means for pivotally moving said electromagnet to vary its relation with respect to said armature independently of a predetermined relationship between said lever and said cam.

2. In a selector mechanism, a mounting plate, a bracket pivotally supported thereby, an electromagnet carried by said bracket, a lever pivotally supported by said bracket coaxially with the pivotal mounting of said bracket, a cam carried by a rotatable shaft, said lever having a portion engageable with said cam as a follower, an arma- .ture carried by said lever for cooperation with means for pivotally moving said electromagnet tovary its relation with respect to said armature independently of a predetermined relationship between said lever and said cam.

4. In a selector mechanism, an electromagnet, a pivotal mounting therefor, rotatable cam, a

lever pivoted at a point remote from the pivotal mounting of said electromagnet and having a portion engageable with said cam, an armature for said electromagnet carried by said lever, and

means for shifting the pivotal mounting for said lever to vary the relationship between said armature and said electromagnet substantially independently of a predetermined relationship between said lever and said cam.

5. In a selector mechanism, a mounting plate, a bracket, an bracket, a pivotal interconnection between said mounting plate and said bracket adjacent one end of said electromagnet, a lever pivotally supportedby said bracket adjacent the other end of said electromagnet, a cam carried by a rotatable shaft, said lever supporting an armature for the electromagnet and having a portion engaging said cam as a follower, and' means adjacent to the point of pivotal movementof. said lever for shifting said point in an arc intersecting a straight line-between the pivotal interconnection of said bracket with said' mounting plate and the point of engagement of the Iever with the electromagnet carried by said cam for varyingthegap' between the electromagnet' and the. armature;

6. In aselect'or mechanism, an electromagnet, a pivotal mounting therefor, a rotatable. cam, a lever pivoted coaxially with the pivotal mounting of said electromagnet and having a portion engageable with said cam, anarmature' for said electromagnet carried by said lever, and means for shifting the coaxialpivot'al'mountings for the electromagnet and the lever to. vary the relationship between the lever and the cam independently of a predeterminedrelationship between the electromagnet and its armature.

'7. In a selector mechanism, a mounting plate, a lever arm pivotally mounted on said plate, a bracket carried by said plate and pivotally connected to said arm, a lever pivotally supported by said bracket coaxially with the pivotal connection of said bracket to said arm, an electromagnet carried by said bracket, a power driven cam, said lever supporting an armature and having a portion engageable with said cam, means for varying the relationship between said electromagnet and said armature and means for varying the relationship between said cam and said lever; the eiiectiveness of said means'being mutually independent.

8; In cooperation with a selector mechanism including a mounting plate having a plurality of apertures, an arm pivoted to said plate on the under side thereof, and having a slot therein in registry with one of said apertures of lesser width than the diameter of said apertures, and an' assembly of selection performing elements. having a portion extending through another of said apertures and pivotally conne'ctedto said-arm, an implement for eiiecting pivotal movement of said" arm including a cylindrical shank dimensioned'to enter and be rotationally guided by the aperture with which the slot in said arm registers and an eccentrically disposed projection of said shank dimensioned'to enterthe'slot in said arm.

9. In an electromechanical device, a bracket, a pivotal mounting for said bracket, an electromagnet supported by said bracket, a power drivencam', a lever pivotally supported by said bracket and having a portion engageable with said cam, an armature carried by said lever for'cooperation with said electromagnet, and means for-shifting plate, a cam carried by said shaft, a lever pivotally supported by said bracket and;having a portion engageable with said cam, an armature for said electromagnet carried by said. lever; and means cooperating with said mounting plate in said bracket for shifting said bracket about the pivotal mounting for varying the spacing betweensaid electromagnet and said armature substantially independently of a predetermined relationship between said lever and said cam.

11. In a selector mechanism, a mounting plate, a pivotally mounted bracket supported by said plate and having a slot therein, an electromagnet secured to said bracket, a' rotatable cam, a selection controlling lever pivotally support'ed'by said; bracket and having a portion engageable with said cam, an armature for said electromagnet carried by said lever, and a rotatable member supported by said mounting plate and having an eccentric head disposed in said slot in the bracket for pivoting said bracket for varying the spacing between said electromagnet and said armature substantially independently of a predetermined relationship between said lever and said cam.

12. In combination a mounting plate, an elec tromagnet carried by said plate, means for pivotally connecting said electromagnet to said plate, a rotatable cam, a pivotallymounted armature for said electromagnet controlled jointly by said electromagnet and said cam, and means co-operating with said mounting plate and said electromagnet for imparting pivotal movement to said electromagnet about said pivotal connecting means for varying the spacing between said electromagnet and said armature substantially independently of a predetermined relation between said armature and said cam.

WALTER J. ZENNER.