US1782491A - Automatic telephone exchange system - Google Patents

Description

Nov. 25, 1930; F. TRAcHsEL AUToMATlc TELEHONE EXCHANGE SYSTEM Filed April 1.2, 1926 2 Sheets-Sheet l gill.

Nov. 25, 1930. F. TRACHSEL v AUTOMATIC TELEPHONE EXCHANGE SYSTEM Filed April l2, 1926 2 Sheeis-Sheet 2 Patented Nov. 25, 193() UNITED STATES FRITZ TRACHSEL, 0F BERNE, SWITZERLAND, ASSIGNOR TO CHR. GFELLER AKTIEN- GESELLSCHAFT, OF BERN-BUMPLIZ, SWITZERLAND A PATENT ori-ICE AUTOMATIC TELEPHONE EXCHANGE SYSTEM Application filed April l2, 1926, Serial No. 101,516, and in Switzerland April l5, 1925.

This invention rela-tes to automatic telephone exchange systemsk and provides an im.- proved construction or arrangement ota pilot switch used in such systems comprising selecting devices located in the exchange and adapted to operate automatically under the control of interrupters or selector discs Which forni part ofthe subscribers sets and which are operated bythe calling subscribers.

According to the invention the exchange comprises a number of similar switching devices (one for each subscriber) adapted to be operated selectively by an operating inember having a step-by-step movement andl so arranged and connected that the switching devices'ofthe calling and called subscribers are first moved into a position ot readiness under the control of the calling subscribers set and arejthen operated automatically by the movement of the operating device so as to eftect the requisite connections between the called and the calling subscribers.

Y In order that the invention may be more readily understood reference Will now be made to the laccon'ipanying drawings 1n which Fig. l is an elevation showing the arrangement of a bank of switching devices,

Fig. 2 is an end elevation in Which only one magnet M39 is shown7 Fig. 3 is a partial top plan view of one of the switching devices,

Figs. 4, 5. vand 6 are enlarged detail views,

Fig. 7 is an enlarged detail view of one of the rods or blades Si?,

Fig. 8 is a diagram ,of the parts used in a single pilot switch.

As shown in the drawings the exchange comprises a number of mechanical switching devicesV (one foreach subscriber) arranged one above the otherr and each comprising tvvo horizontal sliding rods, Zn and Zw", F 3. adapted to operate a number of sets of spring contacts.

The spring-'contacts are arranged in vertical rows mounted'on insulated supports m. For each subsc 1iber there is provided one set of contacts o operated by a cranked end e of the rod Zai' one set of contacts w operated by one end ot the rod Zu and several sets of contacts du which are operated by projections z provided on strips or tongues' H6', H62, attached to spring strips ,t' fixed on the supports m.

As shown in Figures 2 and 4f each set of contacts du comprises eight spring strips constituting four contact points which are arranged in pairs on either side ot' the rod Zu, the contact points above the rod Zu', Fig. 2, being operated by the tongue H62 Whilst the contact points beloiv the rod are operated by the tongue H6. For each pair of tongues H6 andv H62 there is provided on the rod Zu a collar or abutment Mz" adapted to engage and move the tongues H6 and H62 as hereinafter described. The rod Zu2 is provided With similar colla-rs or abutments Mv? adapted to be engaged and moved by` the tongues He', H62 to move the rod- Zag in a. direction to open the contacts p.

The rod Zu is provided With an armaturel An controlled by an electro-magnet M Which is adapted to move the rod against the action of the spring strips ,t from the position shown in Figure 3 towards the position for closing the contacts du. For each set of contacts du provided for one subscriber there is a vertical sliding rod St', S62, or Stg 'in the form ofa flat strip having lateral projections No struck out from the strip adjacent one edge and adapt-ed to engage the free ends of the strips H6", H62. In the normal position of the strips He', H62 shown in Fig. 3 the free ends thereof are clear of the path of movement of the projections No but When any of the rods Zu" is moved by lits magnet M towards the position for closing the contacts Zu the free ends of the corresponding strips He H62 are moved into the pat-h oi movement of the projections No so that by theven tical sliding movement of one of the rods St', S152, Sts` one. of the strips H6", He2 provided for the selected subscriberv can be engaged and moved by one of the projections N 0 so to effect closure of the corresponding contacts du. The strip H6 or H62 also moves the rod Zt by engaging one of the abutinents Mi? So as to break the contact between the spring contacts p. The parts are so proportioned that although thexnagnet M' is capable 'of moving the rod Zu against the action oi' the springs trips f suiiiciently to close the contacts fw, none ot the-contacts 'du or p, are aii'ected until one of the strips He, H62 is engaged and moyed by a projection No. rThe position A o'a strip He after being moved by a projection No is shown inv dotted lines in Fig. of the drawings. 'f

Each ofthe vertical rods S', S152, S253 is l@ adapted to be moved from its lowerniost to its uppermost position stepV by step by means of a pawl KZL" adapted to engage ratchet teeth provided on the rod and controlled by an electro-magnet H and armature A70 and so .3 arranged that when the electro-magnet H `de-energizned thepawl lili `is .out of engagement with the ratchet teeth on the rod as shown inV 2; Downward movement loit the rod during the intervals between succesgg sive operations ci the pawl lila" is normally pr vented by means of a pawl KW controlled by a spring Fe which is capable of moving the pawl into two positions of equilibrium in one of which it tends to engage ratchet teeth formed-0n the rod as shown'in Fig. 2, whilst in the other position it is outof contact with therod. rlwo stops g, g2 are iixed on the lower end of the rod andare adapted to act on a lever or projection iiXed to the pawl KW, so as shown in Figure 2 so that when the rod reaches its uppermost position the projection g moves the pawl KW out ci engagement with the rod and permits the latter to fall by gravity intoits lowerinost position and to act upon the pawl KW by means of a strip g2 so as to restore the pawl Klz'2 to the position shown in Figure 2. Y Y Each of the rods S, S222, Stg has contact arms or brushes Kfcl co-operating with rows of contacts K'clg and constituting a pilot switch. lThis pilot switch is only diagrammatically indicated in Figures l and l2 of the drawings but-is more completely shown in Figure 8. Y. t comprises four contact arms I, ll, 1H, IV, each of which co-operates with a separate rowof contacts. The contact arms l, Il, HI, lV, move together in the example .shown vin the drawings through` fourteen successive positions corresponding to fourteen successive positions provided :tor by the pawls KZ/i, KZ?? and their ratchet teeth. ln each of these positions, each of the contact arms l, ll, Ill, IV bridges two adjacent contacts, certain of which are numbered in Figure 8.

FVhile Figure i 'shows a plurality of the pilot switch mechanisms used in this invention, assembled sideby side to constitute an exchange system, it will be understood that this duplication of the switch elements` is to simply to provide simultaneous service to number oi' subscribers. The invention 'claimed in this application relates more particuiarly to the design and construction of anyone pilot switch, adapted to selectively t5 operate under the controlof a subscribers used with that subscribeiand moved by-hi-s selector disc, common to all such systems, to effect a selective control of speaking circuits co-nnecting two stations.

Generally speaking, the operation of any one of the pilot switches may be described as follows:Y n

Vhen a calling subscriber lifts Vhis telephone, one of the magnets M, say M30, Figure 3, is energized. rlhis causes armature Aam to move rod. Zu a certain distance suiiicient topset one ofV the tongues l-lfe, or H62, sidewise and cause it to be mechanically engaged by the cam projection No on the appropriate selector rod St etc.v This initial movement of thev rod Zu is only suicient in extent to 5.3 close contact fw, which edects a connection Y with the calling subscribers line, all contacts du remain open and Contact p remains'closed. Further movement or' rod Zu can only be effected by manipulating the selector rod Str',

selector disc through theagency of a magnet H, the detailed operation of which has been described above.

This further movement oi' rod Zu takes 90 piace because of the engagement of one of the projections No withv one of the tongues He', or H62, the up and down movementor" the selector bar, carrying the projectionV No, causing the latter toimpart a sideways thrust to rod Zu which closes-one oi thedw contacts .and opens contact p, the edect of opening the last named contact being to isolate that'particular selector, or pilot switch from calling operation. It will thus n be seen that each switch velement initially can be energized by a calling subscriber to automatically effect aV selective line connection with the called subscriber. Y

Summarizing certain essential features f 4disclosed by the pilot switch of th-isjinvention, it will be found that the contact y), Fig. 8, provides an elementl designed to impress.

'on the switch mechanism an initial selective setting of the switch parts which places it in @prie communication with the line of the subscriber called, through contact fw. After this stage of the switch operations, the selector bar appropriate to the desired subscriber is brought into play to eii'ect a further selective setting among the contacts du, which will be determined by his call number, the completion of this operation will result in aspeaking connection having been made automati-A cally by the switch. ln practice,it will be understood that both subscribers will be provided with at least one of the pilot'switches described.

`What l claim is 1. In a switch for an automatic telephone exchange, a plurality of spring contacts placed side by side, cams mounted adjacent said spring contacts, means adapted to'eect a successive piural stage movement of said cams, comprising a slide bar under magnetic plurality of operating other bars transversely movable With respect to said slide bar by magnetic means, one of which is designed to engage said cam and more it from selective position to contact closure position of itsassociated spring contact.

3. ln a telephone exchange switch mechanism, a series of spring contacts placed side by side, cam for. closing said contacts, in

. combination with a slide bar. under magnetic control designed to set said cam to a preliminary closure position, other bars, magnetically operable at right angles to said slide bar and provided with means to selectively engage said cam when placed in said preliminary closure position7 and ak second slide bar movable parallel to said first slide bar under the selective control of said cam to open one of said spring' contacts.

4. In an automatic telephone switch, a series of spring contacts placed side by side in combination with a plurality of parallel sliderods each provided With Yselectively spaced tappets, and means for causing said tappets to close and open certain of said spring contacts through a step by step movement of said rods.

n testimony whereof I affix my signature.

FRITZ TRACHSEL.

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