US2388358A - Impulse transmitter - Google Patents

Description

` Nov.r=6, 1945.

F, A. HUBBARD IMPULSE TRANSMITTER Filed July 24., 1943 2 Sheets-Sheet /NVENTOR BV fAHuBA/w 8 8 Arme/vir,

Patented Nov. 6, 1945 rlracisrnettare, Maplewtoa, N. J., assigner n; nell Telephone Laboratories, incorporates,

New York, N. Y.,fa corporation of New York applicati@ July 24, 1943, serial N. 495,983"

(c1. 17m-38o) This invention relates to impulse transmitting devices and particularly tote'lephone cal-ltransmitters of the key Operated'type.

impulse transmitters ofthe typeemployed at telephone subscribersl stations for the purpose of `controlling the operationoi` automatic switches in the extension of telephone connections must, of necessity, produce pulses that are correctly timed, are clean and free of chatter. esides these essential performance requirements, such transmitters should also embody characteristics that render them attractive .from the -subscriberls viewpoint; l

It is the object of this inventionto provide an impulse transmitter ofV the key `operated type which functions to transmit impulses that are correctly timed and-which, for its operation',im poses a minimum of requirements on the subscriber. y

This object is attained inA accordance witha feature of the invention by combining inaunitary structure an impulsecounter which is variably set by the subscriber, by means ofmanually operable keys, to predetermine the num-ber of impulses to be transmitted, and means which functions to restore the counter stfep-by-step` a-t the speed or frequency at which it is desired to transmit t-he impulsesand to simultaneously op erate impulse controlling contactl springs. More particularly, theY transmitter of this invention which functions whenever rjriaiiuall contemplates the use of an escapement Wheel which is rotatable in oneA direction under the 'control of manually operable keys, through arcs Whose lengths determine the number of impulses to be transmitted, and of an electromagneticals ly controlledvibratable-member, tuned to vibrate at the frequency at which the impulses are to be tra-nsmittedimhich functions to count oi the number of pulses predetermined by the lsetting Aof the escapement wheel ando to simultaneously operate impulse controlling springs.-

u Another feature of the invention provides for the inclusion of the operating Winding and contacts ofk a controlling electromag'net in the .pulsing circuit, whereby the electromagnet functions as an interruptor to drive the pulse counting escapement4 wheel on electrical energy derived from the central oiiice, or exchange battery, an'd the interruptor itself functions to repeatedly interrupt `the pulsing circuit to produce pulses.

A further feature of the invention 'renders the a'ctualtransmission of pulses wholly independent of any 'control by an actuated key. More particu larly, lai'l'thin'g` means is provided which serves to hold an actuated key in tsbperateu 'position until the pulse counting sapinrt wheel been returned to normal and 'a 'cbvf'nplete si'ies of impulses transmitted. Y v f Another feature contemplate'sthe iis l clude the electromagnet ing circuit. An ancillary 'feature provides auxiliary set of contact'ssrllnjgswnlcr c6 tile inclusion of the electromagnetic inter'pte' 'in the pulsing circuit. These 's'piigs i' -ltmatically operated to di'scoinet the iiite rlpter from the pulsing circuit when the swpfeneiit Wheel has returned to norial"threby"^ 'deiing the holding of akey operated 'fraiabrll period oftime ineect'ive to cefse the transmission of false pulses.

sull another feature is e" bodied intre l tural design of the transmitter which peirlil'fs bf a uniform length `of stroke f'rl all keys and 'the application of substantially the 'saine f'e' t'o each key for its operation.

Other features are structural coiipctness which permits a key arrangement as'co'pact as is consistent with deiil'ate claiarie to al-V low for large angers 'and a certain analist 'f carelessness vin keying;I neatness in appearancei full Visibility of the designation clia'iacter'swlh identify the keys; and-othercharacteristicswhich permit of a minimum of eil-oft by, and iicvenience tothe subscriber in the operation o'f tlie transmitter.` k n These and other features of the invention will be readily understood from the following detailedv description when read connection with the accompanying drawings, in which;

ig. 1 isa side elevation of alteluephone s et (handset omitted) equipped withl a call transmitter of the present invention. This View is taken along the line `l--l of Fig. -2, looking in the direction of the arrows; l

Fig. 2` is affront view of the set shown 1. In this view a portion ofthe forward-casing wall is brokenawayto expose the transmitter mech-'- anism housedinthe casing;` k u u Figs.A f3' and 4 are side views of details of the transmitter operating mechanism-;-Fig-: 3- shows the mechanismfin lits normal unoperated 'condition and Fig. 4 shows l the same mechanismin its fully operated position; and p Fig, 51 is al combined structural andcircuit schematic` which illustrates the various circuit controlling springs embodied in the` transmitter structure -and their circuit relations relative to The telephone substation set S is normally connected to the line L by way of the normally closed parallel associated contacts a and a. The electromagnetic interrupter Whose interrupter contacts b are serially included with its operating winding in the pulsing circuit is 'normally open circuited at contacts c' and c which are serially related. The contacts a and c are of the makebefore-break type and are controlled by an operating lever 13 through an insulating stud 16 carried on an integral extension thereof. The contacts a and c' are also of the make-beforebreak variety and are `controlled by cam lever 51 through the stud 63.

The transmitter includes ten individually manually operable key levers 36 and when any such lever is actuated incident to the depression of a key 40, aV toothed segment 36 formed integrally with the lever 36 causes lever 46 to rotate counterclockwise on shaft 45. The rotation of lever 46 is due to the meshing of the teeth of segment 38 with teeth on one end of the lever 46. The lever 46 carries at its outer end a toothed rack 49 which is equipped with one or more teeth, the maximum number being ten. As the lever 46 rotates, the teeth on ratchet 3| are engaged by the teeth of the rack 49 and the ratchet is rotated through an arc commensurate with the number of teeth on therack. The ratchet 3| is ixed to shaft 2'4 which also has xed thereto a camming disc 33 and an escapement wheel 32." The disc 39 and wheel 32 accordingly are rotated simultaneously with ratchet 3 I.

The camming disc 30 is provided with a notch 58 which, when the disc is in its normal position, accommodates one end of each of the levers 56 and 51. As the cam 30 moves olic normal, the ends of levers 56 and 51 are forced out of the notch 58 and ride on the cam periphery. The lever 56 functions to prepare the latch 2| -22 for engagement by the notch 91 in the rack 49 and the lever 51functions to operate Spring contacts a and c. Since the cam 30 moves off normal substantially as soon as the'key lever 36 starts its downward movement, the contacts a and c are actuated during the depression of a key and before the key reaches its fully depressed position. Contacts c' connect the winding of electromagnet |00 to contacts c while contacts a open one of the parallel connections of the subset S to the' line L. The subset S however is still connected to the line by contactsva.

Subsequent to the operation of the contacts a and c'y and particularly, when the key lever 36 is fully depressed, the'integral extension 12 of lever 36 engages the lever 13 causing it to function and operate contacts u and c. Thus when the keyis fully depressed the subset S is disconnected from the line L and the winding of magnet I 00 is substituted therefor.

The escapement wheel 32, as indicated above, is fixed to shaft 24 and rotates through an arc similar to that through which the ratchet 3| is rotated. The wheel 32 isprovided with ten teeth so that for each length of arc through which it is rotated, the wheel is advanced a corresponding number of teeth and this position of the escapement Wheel is attained when the key lever 36 reaches the bottom of its stroke, which as described above, also determines the effective connection of the magnet |00 to the line L.

.As the rack 49 reaches the upper limit of its travel the notch 91 is engaged by the latch bar 2| causing the key lever 36 and the lever 46 to be locked in their operated positions.

The electromagnet |00 now functions as an interruptor and through its armature 80 and escapement pawl 99 causes the escapement wheel 32 to be driven back to normal position step-bystep. Thus for each energization of magnet |00 the wheel 32 is rotated in a counterclockwise direction one tooth, and the pulsing contacts b are operated once. When the wheel 32 is returned to normal, the springs b will have been operated a number of times corresponding to the number of teeth through which the wheel 32 was advanced incident to the depression of a key.

When the cam 30 restores to normal coincidently with the return to normal of wheel 32 the ends of levers 56 and 51 resume their normal position-s in the notch 50, lever 56 operating latch 2|-22 to cause the release of the operated key lever, and lever 51 restoring contacts a and c' to normal. Contacts c open the circuit to interrupter |00 and contacts a reconnect the subset S to the line L. The latter operation is completed before the circuit to magnet |00 is opened. Thus the magnet resumes its normal condition and pulsing ceases. The armature 80 of magnet |00 is mechanically tuned to vibrate at the frequency or speed at which it is desired to transmit pulses so that the pulsing contacts b are operated a number of times corresponding to the setting of escapement wheel 32 and at a speed determined by the tuning of armature 80. The energy for operating the magnet |00 is derived from battery I 0| located at the central oiiice.

Should the subscriber hold the actuated key depressed for an abnormal period of time the transmission of the series of impulses is not interfered with since the pulsing of the magnet |00 automatically ceases when the desired number of pulses has been transmitted and when the cam 30 restores to normal position. Contacts c serve to insure the opening of the magnet circuit at the proper time while contacts c preclude the inclusion of the magnet Winding in the pulsing circuit until the actuated key is fully depressed. Contacts a and a perform obvious functions, the latter serving to reconnect the subset S to' the line immediately upon cessation of the pulses.

Referring now particularly to Figs. l, 2, 3 and 4 of the drawings, the call transmitter of this invention is housed within the telephone set casing I0 and is carried on the base II- thereof by means of a number of brackets and mounting frames. One of the mounting frames is made up of two irregularly formed brackets I2 and I3 which are secured to the base II by means of screws I4. These brackets extend vertically from the base I and at their upper ends are joined by a cross bar I5 which is secured to the ends of the vertical brackets I 2 and I3 by means of screws or rivets I9. The cross bar I5 serves to lend rigidity to the vertically extending brackets I2 and I3.

Immediately in front of the cross bar l5 is located a rod or shaft I6. The ends of shaft I6 pass through apertures in the upper ends of brackets I2 and I3 and are held against longitudinal displacement bythe collars 2,0.v This shaft assenso 'serves to, support a latohing1 inechanisfnil consist ing of two slightly' arcuate arms '22 fand 23 in isfree to rotate about the shaft |16 andfserves to locktheoperating arm46 andits corresponding key lever 36 inem-operated posi-tion as hereinbe- Afore described. f

' A' sha-ft 24 is `also supported between? the brackets 12 and i3 and is adapted tor rotationin 'sufitahly 'located apertures in the brackets.. 'shaft is llocated below vthe Ishaft 4TF6 and. in suhsltantial `afl'igrnn-ent therewith. ItV serves to support a Vcam 30, ten ratchet wheels '31h and-an escapement wheel 32. The cam, ratchet wheels -and'rescapement wheel lare all fixedt'o the shaft 24a'nd are rotatable therewith. 'The collars .25 servie to prevent longitudinal displacement of the shaft24. A pair otspider-like 4brackets 26. are secured "to the base lil `lay-screws "21 and are located-on either side oirthe base near its forward end. These brackets serve to support Ia shalt 1.1 which, 1in turn, supports ten key levers 66. Each key lever consists of two integrally for-med portions, the 'lever portion perse, and la gear :seg-ment 38.. The integral ci. the two .elements is indicated by thenumber Sain Fig. '2. .'.Ihetenlevers and their associated gear segments are freelyl rotatatile onthe shaft .I 1. Each key lever is provided within depending lug i28 to which one end of a .springt 95. .is fixed, the other ends ot `all. such springs. Boeing fixed to a common shaft 29 which is .supportedin apertures .located at the lower rear of the brackets 26.

Eachfoff the brackets 25 is provided with a substantially centrally disposed ver-ticaLprojection33 which serves to support va Vstop rod 3'4. The stop .rodm'determines the normal pos-itior-isof` the ten keyv levers 36 and-each keylever is normally held against thestop rod vby its vindividual spring '95.

As more clearly shown in Fig. 2; the upper end .oieach ofjthe-key leversv 36. is 'bent at .right angles toprovide a seatfor a. button yor key 40 which. is .lined toits respective seat in any suitable manner. Inorder'to lend compactness to the structure. and toprovide for a compact and orderly arrangement of the buttons y40, the upper ends of. iive of the key levers` 36, are :bent tothe left, viewing'Fig. 2;, andthe upper ends of the remaining ve .key levers are bent tothe right. By this. construction the ten. keys .oricuttons lli` may be arranged in vtwo horizontal rows of iive buttons each with the buttons oi; the upper row in alignment with those ofthe lower row. The shaft liisprevented from moving longitudinally by collars 41 fixed thereto impositions such as toabut the inner face of the brackets .2;6; The key levers 36 are heldinspaced relai-,101i` by means ofl collars 42, one of whichis interposed between each pair of adjacent levers. The .collars 43 xedto the shaft vI1, serve to hold the assembly ofl key levers 36 and interposed col- .larslin position on the shaft 11.

The spider-like brackets 26 alsoserveto mount the shaft ,45, which is indicated in Figs. 1, 3, 4.and ybutwln'chl does not appear in Fig. 2` because` of its-locationin back of shaft I1. Th-isfshaft serves tornount ten operating levers. 46 for rotation thereon. Each operating lever 46,'as clearly illustrated;r in Figs. 1, 3 and 4, is` an irregularly formed elongated member terminating at its outer 'end in anarcuate arm 44 and at Vits inner end n a .toothed segment. The toothed end `of 4eachioperating lever.46 is in permanent meshwith acorresponding key lever .gear segment 38. `Each operatingleven *"46` at its Guten endcarries'a tegra-lly Ijoinedby a cross-piece 21; This latch Y tootl'ied-acit 4'@ .inis'uc'h lalmanner that fthe .latter is; capable oslight movement longitudmally rela* tive toits associated .lever t6.. This movement is made'possilclelcyf-` providing the tooth rack14'9 :with an inwardly projecting armf41 having a longtus dinal -sl'ot 418; through which protriidsrV the. pins 510 whichare fixed tothe lever 46. ,The arm -"4f1:.1is provided with a depending .lug 5I.l to. which-vene end ofc'coil spring `52 is secured, the otheremif tof springl 512` .being :securedfto a similar .depending lug 56 formed on the lever No purpose fof providing 'a construction whereby the toothed .sector 49 may vmove relative to its supporting lever 46 `will-he pointed out hereinafter. v

V'lhecam` 3U. is provided with `a pin` 'lwhich normally abuts astop 55 fixed to the bracket 122.. The .stop 55 determines the normal position. of the cam 35'. On its periphery the cam. 31! is-.pro-

'vided with a notch k58 which, when the cam :is

in its normal position accommodates the freeV ends of two. cam levers 56` and 51. The lever` 56fisa tripping lever and is provided with a backwandly projecting arm 591 which, when the cam 3`i'snin its normal positionv illustrated in Figs. .1. and is in engagement with the projecting lugl': on thetlatchy arm 22. A'Ihe arm '59. thus serves asia stop for the latching mechanism andrdetermines its normal position. The lug 60 of theiatching mechanism is held in engagement with the. arm

59 of lever 56'. by the spring '61., one end.` of which. is secured to4 the latch and the other end of l which is attached to a pin 62' fixed to the bracket I2 The cam end of lever :56.ishelcl inwconstant engagement with the periphery of cam 351by means of spring 65., one end of which is: secured vto the pin 62l and the other end of which. is 'atttached to the lever 56. From the interaction. of the cam 3B, lever '56: and thelatching mechanism it is apparent that when the cam 391 moveslol normal, that is, when it starts rotating in. a clockwise direction, the cam end of theiever is -forced out of` the notch 58. and rides :on the pe riphery of the cam. The lever thuspivots about its support 66 allowing thespring 6l` to pullthe latch downward.V The latch thus assumes `a po.-

sition in which it is engageable by the notchQl in the arcuate portion 4t` of the operating arm 46 when the latter is actuated as willaallpear. more fully from a later description.

The cam lever 51 also has its free end nor.- mally engaged ini the notch 58 of cam 30.so!that when .the cam 30 moves off normal, the lever 51 rotates 'about its pivot 68 in such a. manner that the insulating `roller or stud B3carriedon a lower extension of thelever 51 functions to operate. the springv contacts c and a. A bracket GSsecured to the base Il by the screws 1-0 servesctoipivotally support the .lever 51 and also to mount the coil spring 1I, the latter performing an obvious function.

Each of the ten ratchet wheels 3i.` is` individual `to a particular one of the ten toothed vracksV 49 'and each is provided with a plurality ofteeth. The ratchet wheels 3l are sopositioned .relative to theV button 40 associated therewith, the corre#- sponding operating lever 46 is caused to pivot on shaft 45 by virtue of the meshing of the teeth of .the lever 46 with those of key lever segment 38. As the operating lever 46 moves upwardly, the toothed rack 49 carried thereby experiences a similar movement and the teeth of, the latter engage the teeth ofv a ratchet wheel 3| causing the `shaft 24 to rotate in a clockwise direction; 'I'he Cil pulsing circuit. Thus the pulsing circuit is interrupted a number of times corresponding to the numberof teeth the escapement wheel 32 was advanced'incident to the depression of a key 1ever. I

The teeth on the ten toothed racks 49 vary in number from one to ten and the teeth appearances start at the lower end of the sector. In this mandepressed engages a common .bar 13 which is pivotally supported by two vertical projections 14 of the brackets 26. The bar 'I3 is provided at its left end, viewing Fig. l, with a lug projecting inwardly from the pivot support 15 which carries an insulating roller or stud 16. When a key lever is fully depressed its associated lug 12 engages the bar 13 causing the insulating roller '|6 to operate the spring pile-up 'Il which includes the spring contacts a and c. These spring contacts are of the make-before-break type so that the contact c closes before the contact a opens as indicated in the description of Fig. 5 hereinbefore made. The contact operating bar is held in its normal unoperated position against the back stop 'I9 by means of spring 18.

At the rear of the operating mechanism thus far described is located an electromagnetic interrupter |00 whose armature 80 is mechanically tuned to vibrate at the frequency or speed at which it is desired to transmit pulses. The interrupter |00 is mounted on a bracket 8| secured to the base by means of screws 82 and is provided with a set of contact springs whose contacts b are normally closed and are adapted to be actuated by the armature end carrying the kstud 83. Included in the spring pile-up assembly is a bracket 84 which pivotally mounts the escapement pawl 99. The irregularly shaped armature 80 of interrupter |00 has its uppermost end slotted for the purpose of receiving the '.pin 85 secured to one arm of the pawl 99. The pawl 99 and the teeth of the escapement Wheel 32 are so designed that when the shaft 24 is rotated in a clockwise direction the escapement wheel will experience asimilar rotational movement and the pawl 99 will be actuated though performing no useful function at this time. However, when a key lever 36 has been depressed and the shaft 24 rotated in a clockwise direction, and when thekey lever reaches the bottom of its stroke and causes the operation of contacts a and c of the spring pile-up 11, the winding of the interrupter 00 is eifectively included in the pulsing circuit and Vis energized from the source IUI. The interrupter thereupon causes the armature 80 `to vi` .brate at the frequency or speed at which the pulses are to be transmitted and by vintue of its coupling with the pawl 99 operates the latter causing the escapementvwheel 32 'to be returned to normal position, step by step, at a speed or frequency determined by the mechanical tuning ofthe armature. The contacts b are serially included in the pulsing circuit and each time the winding of interrupter |00 is energized, the ar mature 80 acts upon the contacts b causing them to open the interrupter circuit and therefore, the

ner the length of the operating stroke for each key is made the same and the operating mechanism required to be moved by the keys is displaced the same distance for each key operated, thereby requiring th application of substantially the same force to all keys.

A complete cycle of operations of the call transmitter resulting from the actuation of any key will now be described and for this purpose particular reference is made to Figs. 1, 3 and 4. Assuming the`key or button 40 bearing the designation 5JKL is actuated, the corresponding key lever 36 and its integrally associated gear segment 38 are rotated on the shaft I1 in a clockwise direction. By virtue of the meshing of the teeth of gear segment 38 with the teeth on the end of a corresponding operating lever 46, the lever 46 and its associated toothed rack 49 swing upwardly. In the case described, the toothed rack 49 has five teeth so that the rack will pass the corresponding ratchet wheel 3|, for a slight interval before the rst tooth of the rack engages the rst tooth of the ratchet'wheel. The ratchet wheel will then begin its clockwise rotation and will advance through an arc corresponding to the live teeth on the toothed rack 49. As the ratchet wheel begins its movement, the shaft 24 starts to rotate causing the cam 30 to rotate also. As the cam 30 moves off normal the cam levers 56 and 5'! are actuated, the former permitting the latch bar 2| to be moved under the action of spring 6| to a position in which it will be engaged by the notch 91 in the arcuate end piece 44 of the operating lever 46, and the latter causing the operation of spring contacts c and a. The closure of the spring contacts c partially completes the operating circuit for the interrupter |00 and the opening of contacts a opens one of the parallel connections of the subset to the line L.

The rotating shaft 24 carries with it the escapement wheel 32 so that the latter is advanced five teeth corresponding to the five teeth in the toothed rack 49. When the key lever 36 is fully depressed the arm 44 of the operating lever 46 reaches the upper limit of its travel and the notch 91 thereof is engaged by the latch bar 2| so that the operated key lever 36 and its corresponding operating lever 46 are held locked in their operated positions. Simultaneous with the latching of the operated levers, the contact springs of spring pile-up 11 are actuated by the engagement of the key lever projection 'I2 with the operating bar 13. Thus the subset S is disconnected from the line by the opening of contacts a and the operating circuit for interrupter |00 is completed by the closure of Ycontacts c. The interrupter immediately starts functioning and through its armature and the pawl 99, the escapement wheel is driven back to normal, step by step, at a speed determined by the mechanical tuning of the armature 80. Each time the escapement wheel is returned one tooth in a counter-clockwise direction by the action of pawl 99, the interrupterA contacts band therefore, the pulsingcircuit is interrupted once. In the case at hand, the interrupter. would function five times to cause the transmission of five correctly timed pulses.

" Theshaft 24-v audits cam 3,0 alsofrestorev to Vnormal;with' the escapementwheel 32 and when the .pin 54- of the cam 30 engages the stop 55 the movementof the shaft,v cam, ratchet wheel and escapement Wheel is arrested and the cam levers 5'6-l and 51 resume their normal positions. That is, their free ends move into the notch 58 in the cam periphery under the action of their respective springs 55 and H. The camlever 56 trips "the latch .bar 2|- causing the disengagement of the bar from the notch 91 in the arm 44 of the` operating lever 4-6. The operating lever AB and its corresponding key lever-35 thereupon return to normal, the action of coil spring 95 serving to insure the restoration of these elements to normal. In order to insure thefpassage of the teeth rof rack 49 by the teeth of the; ratchet wheel 3l as the operating lever returnsto normalposition, the rack 49- is permitted a slight longitudinal displacement along the axis of the supporting portiener the operating lever lili.` This movement is made possible bythe slotl 4'8 and pins 5.0. As the teeth of therack 49 lpass over the` teeth of the ratchet Wheel 3l, the rack 49 is forced inwardly and away from the ratchet wheel thereby insuringl the relativelyvv free passage of the rack by the ratchet Wheel and precluding the possibility ofjamming, i vWhen the cam lever 5l resumes its normal position the contacts c are opened and the interrupter |00 is effectively disconnected from the /line to preclude the possibility of any further pulsing action thereby.

It Will be: observedy that should Kthe subscriber hold the` operated key lever down foran interval of timevvhich extends beyond the pulsing period noV harmful results ensue, since the interruptor l00 is automatically disconnected from the pulsing circuit by the opening; of contacts c' which l occurs when the correct number of impulses has been transmitted and the escapement Wheel 32 has returned to normal. The spring pile-up which includes contacts c also: includes the contacts a" which are connected in parallel with contacts a of spring pile-up 1'1'. The contacts a' insure against allost connection should the subscriber hold the key operated until after the train: of pulses has been transmitted and. thereby maintain the contacts a open and the subset S disconnected from the line L. The closure' of contacts a insures` the reconnectionof the subset` to the line even though an actuated key is held operated; Contacts a are intended to close before contacts c open What is claimed is:

1. The combination in an impulse transmitter of` an impulse counter, means for variably presetting said countertd predetermine the number of impulses tobe transmitted by said transmitter, means for operating said counter to count off the predetermined number of impulses, a plurality of manually depressiblb keys, means controlled by said keys during the depression. thereof forl acie tuating said presetting means, means controlled said keysA when fully depressed for causing the actuation of said counter operating means, and pulsing contacts actuated by said counter operating means.

2. The combination in an impulse transmitter F of an impulse counter comprising an escapement Wheel, means for variably presetting said escapement wheel to predetermine the number of impulses -to be transmitted by said transmitter, means for operating said.escapement wheel to ,ca-use it4 to count ofi thepredeterm-ined number of impulses comprising an escapement pavvlcoioperatively associated with said escapement Wheel and amember supportingxsaid `p awl and: vibratable at a predetermined frequency of vibration, a plurality of manually depressiblekeys, means controlled by said keys duri-ng the. depression thereof foractuating said presettingzmeans, means controlled by saidkeys fully` depressed for causing said `n-iernber rto vibrate at its predetermined frequency ofyvibration vvhereby said escapement Wheel operates tilt-rougir said escapemen-t Y pawl` to count; oii the predetermined number of impulsesnandpulsing contacts controlled by said vibratable '.rnember.V

if.. 3v. A. device -for transmitfng a predetermined number of impulsesat a predeterminedfreduency comprising in combination, d .4 pulsing f contacts, means for operating said pulsing" contacts :at Vthe said predetermined frequency, and means forfpredetermining the nu `ber oi operations of said contact operating `means comprising an impulse coun-ter rotatable in either direction, aplurality of manually` operablekeys; means Vcontrolledby any of said keys 'during the depression. thereof for rotating said counter inone direction through an arc whose lengthdetermines the number `of operations of said contact` operating meansvand means responsive tothe full depression-.of any `of said keys for renderingsaidr contact operating means effective to rotatefsaid counter in.- thereverse direction and tolsimultaneouslyoperate said pulsing contactsa number of times corre.-

spending-to the arc lengththrough Whichgsaid counter was rotated in the said one direction. l 4. A telephone transmitter comprisingan electromagnetic pulsing device, rotatable ,means for predetermi-ningthe number of operations ot said electromagnetic pulsing device, a plurality of man.- ually depressible keys,` means control-led by said keys during the. depression` thereot for variably setting said predetermi-ning` mear'is,` means responsive to the full depression,v of any yof Vsaid keys for energizing saidelectromagnetic pulsing f device, and means controlled by said electromag netic pulsing device when energized for restoring said predeterminingmeans.

5. A device for transmitting a predetermined number of impulses at a predetermined frequency comprising in combinationpulsing contactsan armature mechanically tunedto vibrate at the said `predetermined frequency for' operatingv saidpuls` ing contacts, an electromagnet for operating said armature, and. means' for limiting the number of operations of saidarmature comprising an impulse counter rotatable in either direction,` manually' operable means for rotating saidVV counter in one direction from normal through an arc Whose length determines' thenumber of operations of said armature, meanscouplng said con-tact operating means and said counter, and means controlled by said manually operable means for rendering said electromagnet effective to operate said armature, whereby said armature vibrates lat the said predetermined frequency and functions through said coupling means to drive said counter in a reverse direction and to simultaneously operate said pulsing contacts.

6-. A device, for transmitting a predetermined number of impulses` at a predetermined 'frequency comprising in combination, pulsing contacts, an armature mechanically tuned to vibrate at the said predetermined frequency for operating said pulsing contacts, an electromagnet for operating to normal, step by step,

for rendering said electromagnet effective to operate said armature, whereby said armature vibrates at the said predetermined frequency and functions through said escapement pawl to rotate said escapement wheel in the reverse 'direccablyrotatable impulse counter, a plurality of manually depressible keys, means controlled by said keys during the depression of any thereof for rotating said counter in one direction from its normal positionthrough an arc of predetermined length, means controlled by said keys when fully depressed for including said interrupter in said pulsing circuit, means controlled by said interrupter when included in said pulsing circuit for driving said counteroin the reverse direction toits normal position, whereby said interrupter funcy tions during the reverse rotation of said counter tion to normal, and to simultaneously operate said pulsing contacts.

7. A device for transmitting a predetermined number of impulses at a predetermined frequency comprising in combination, pulsing contacts, an armature mechanically tuned to vibrate at the said predetermined frequency for operating said pulsing contacts, an electromagnet for operating said armature, and means for limiting the number of operations of said armature comprising an escapement wheel rotatable Yin either direction, manually depressible k'eysmeans controlled during the depression of any of said keys for rotating said escapement wheel in one direction from normal through an arc whose length determines the number ofoperations" of said armature, means controlled by any of' said keys during the depression thereof for preparing an operating circuit for said electromagnet, an escapement pawl coupling said armature and said escapement wheel and adapted to drive said escapement wheel to normal when the operating circuit for said electromagnet is completed, means controlled by any of said keys when fully depressed for completing the operating circuit for said electromagnet whereby said armature vibrates at the said predetermined frequencyand functions through said escapement pawl to drive said escapement wheel back to normal and to simultaneously operate said pulsing contacts, and Vmeans effective when said escapement wheel restores to normal for opening the operating circuit for said electromagnet.

8. A telephone transmitter comprising pulsing contacts, a vibratable member for operating said contacts Yand mechanically tuned to vibrate at a predetermined frequency, an electromagnet for Yoperating said vibratable member, means for predeterminingV the number of vibrations of said vibratable member, a plurality of manually depressible keys, means controlled by said keys during the depression thereof for variably setting said predetermining. means, means responsive to the full depression only of any of said keys for energizing -said electromagnet whereupon said vibratable member is vibrated at the said predetermined frequency to operate said pulsing contacts a number of timesl corresponding to the vsetting of said predetermining means, and means operating automatically when said contacts are operated a number of times corresponding to the setting of said predetermining means for deenerglzing said electromagnet.

9V. In combination, a pulsing circuit, an electromagnetic interrupter elective to interrupt said pulsing circuit when included therein, a reciproto interrupt said pulsing circuit a number of times commensurate with the length of arc through which said vcounter was rotated during the depression of any of said keys, and means responsive to the return of said counter to its normal position for automatically vexcluding said interrupterfrom said pulsing circuit.

10Q In combination, a station, a pulsing circuit, and an impulse transmitter at said station comprising an electromagnet normally excluded from said pulsing circuit and operable to interrupt said pulsing circuitwhen included therein, manually depressible keys, an'impulse counter adapted to be set in a plurality of positions each of which determines the number times s aid electromagnet operates to interrupt said pulsing circuit, means controlled by any of said keys for setting said counter in one of said positions, means responsive to an off-normal movement of said counter incident to the depression of said any key for initiating the inclusion of said electromagnet in said pulsing circuit, and means controlled by said any key when fully depressed for completing the in- -clusion of said electromagnet in said pulsing circuit, whereupon said electromagnet functions to interrupt said pulsing circuit a number of times corresponding to the setting of said counter.

11. j An impulse transmitter comprising in combination, pulsing contacts, an electromagnetic interrupter having an armature for controlling the operation of said pulsing contacts, a plurality of manually rdepressible keys, an impulse counter comprising an escapement wheel, an escapement pawl carried by said armature and adapted to driveV said escapement wheel in one direction when saidarmature is vibrated, means controlled by any of said keys during the depressionl thereof for driving said escapement wheel in the other direction through an arc of predetermined length,

means responsive to the full depression of any of said keys for energizing said interrupter whereupon said armature is vibrated and said escapement wheel is driven through said escapement pawl in said one direction through an arc of said predetermined length and said pulsing contacts are operated, means effective when any `of said keysis fully depressed for locking the key in its depressed position, means eiective when said escapement wheel is driven through an arc of the said predetermined length in the said one direction for releasing said key, and .other means simultaneously effective for deenergizing said interrupter.

12. An impulse transmitter as described in the preceding claim wherein said other means functions to deenergize said interrupter irrespective of the depressed condition of said key following the operation of said key releasing means.

FRANCIS A. HUBBARD.

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