US2277191A - Combined line and cutoff relay for telephone systems - Google Patents

Description

March 24, 1942. R,A S, WILBR 2,277,191

COMBINED'LINE AND CUT-OFF RELl FOR TELEPHONE SYSTEMS Filed Nov. 2, 1959 FINDER START W fm" l l 4a? lso '74 L/NE F/NDER srARr /NVENTOR R. S. W/LBUR Patented Mar. 24, 1942 COMBNED LINE ANDl CUTOFF RELAY FOR TELEPHONE SYSTEMS Ray S. Wilbur, Summit, N. J., assigner to Bell Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application November 2, 1939, Serial No. 302,517

Claims.

This invention relates to telephone systems and more particularly to a combined line and cutoff relay structure applicable to a subscribers line for replacing the usual individual line and cut-off relays and for performing all of the functions thereof. It is the object of the present invention to simplify and to reduce the cost of the individual relay equipment of subscribers lines.

To attain this object a relay of a standard type, now used extensively in telephone systems, is modined by the addition of two cam wheels operable step by step by a pawl secured to the relay armature which cams are eiective to control certain of the springs of the relay spring pile-ups, other springs of the pile-ups being operable by the armature in the usual manner, while still other springs are operable both in the usual manner and by the cam wheels. The cam wheels are secured to a shaft supported transversely of the front end of the relay core, one of the cam wheels having iive teeth and the other ten teeth, the latter also serving as a ratchet wheel with which a pawl secured to the armature cooperates. The shaft is thus rotated one-tenth of a revolution upon each attraction of the armature.

In its normal condition, the windings of the relay are connected over normally closed contacts of certain of its springs to the tip and ring conductors of the line so that when the line loop is closed to initiate a call, the relay armature is attracted and through the pawl carried thereby starts to rotate the cam wheels. A tooth of the ten-toothed cam wheel in its half step position rst operates certain contact springs to close a local operating circuit serially through both windings of the relay to insure a full attraction of the relay armature. In the fully attracted position of the armature, the local energizing circuit is opened, both windings are disconnected from the line loop and the ve-tooth'ed cam wheel operates springs to connect the tip winding of the relay to the sleeve terminal of the line and operates other contact springs to prepare a signaling circuit, which as illustrated may be the start circuit of a line finder.

With the energizing circuits of the relay now opened, the armature restores engaging contact springs to complete the line-finder start circuit or signaling circuit. The relay has now performed all of the functions normally performed by the usual line relay. When the started line finder iinds the calling line, the relay is again energized by its tip winding over contact springs closed by the iive-toothed cam wheel and at tracts the armature to advance the shaft another step, the armature in its attracted position opening the start circuit and holding the contact springs closed whereby the tip winding remains connected to the sleeve terminal and is maintained energized until the connection is released. At this time, both windings of the relay are disconnected from the line loop. When the connection is released, the relay deenergizes and returns all contact springs to their normal condition. The relay has now performed the functions normally performed by the usual cut-off relay;

When the line is seized as a called line, as for example over a connector multiple, the tip winding thereof is energized over the connector sleeve terminal and the armature in passing to its fully attracted position advances the cam wheels, the ten-toothed cam wheel momentarily closing a local energizing circuit through both windings of the relay and the five-toothed cam wheel opening contact springs included in the energizing circuit through the tip winding.y In its fully attracted position, the local energizing circuit is opened at other contact springs whereby the armature is restored and closes the line-nnder start circuit. The energizing circuit through the tip winding of the relay is, however, immediately reclosed and the relay again attracts its armature advancing the shaft another step, thereby opening the start circuit. This momentary closure of the start circuit is not effective in this Case to start a line nder since the line-finder start relay may be made slow to operate. The energizing circuit through the tip winding is now maintained over contact springs which were permitted to close by the second step taken by the Ve-toothed cam wheel and both windings are disconnected from the tip and ring conductors of the line loop. When the connection is released, the relay releases and restores all of its contact springs to their normal condition. Thus when the line is seized as a called line, the relay performs all of the functions performed by the usual cut-01T relay.

The invention having been described in a general manner, reference may now be had, for a more comprehensive understanding thereof', to the following detailed description taken in connection with the accompanying drawing in which:

Fig. l is a side elevational view of a relay in which the present invention is embodied;

Fig. 2 is a front elevational view of the relay;

Fig. 3 shows schematically a subscribers line, a line iinder having access thereto, the relay and the circuits controlled thereby in their normal condition;

Fig. 4 illustrates the operated position of the relay and the condition of the circuits controlled thereby immediately following the initiation of a call on the subscribers line and the closure of the line loop;

Fig. 5 illustrates the succeeding released position of the relay and the condition of the circuits controlled thereby at which time the lineiinder start circuit is closed; and

Fig. 6 illustrates the succeeding operated position of the relay and the condition of the circuits controlled thereby at the time the line terminals are seized by the line nder.

The improved relay structure is of the general type disclosed in Patent 2,178,656, granted November '7, 1939 to P. W. Swenson and comprises a supporting bracket I to which the rear end of a forwardly extending core 2 and a hinge bracket 3 are suitably secured, a coil 4 having two windings surrounding the core'2, a U-shaped armature 5, the arms of which are pivoted by pins 6 on the arms, of the hinge bracket 3 and the forward cross reach of which cooperates with the pole face 'I of the forward end of the cord 2, a back-stop screw 8 secured in the forward end of the core 2 having a back-stop nut 9 thereon for adjusting the normal air-gap between the armature and the pole face of the core, and two spring pile-ups I3 and II, one on either side of the coil, insulatedly supported on and secured to the mounting bracket I by screws I2.

In accordance with the present invention, this relay structure has been modied by the addition of two cam wheels I3 and I4 secured respectively on the opposite ends of a shaft I5 which is rotatably mounted in a bracket IE extending transversely across the forward end of the relay core and secured to the core 2 bythe screw Il. The cam wheel I3, which is provided with ten teeth and serves also as a ratchet wheel by means of which both cam wheels may be rotated step by step under the control of spring pawl I8 secured to the end of the armature 5 by screw I9. cooperates with a stud 20 of insulating material secured to the contact spring 2|. The cam wheel I4 has ve teeth and cooperates with a stud 22 of insulating material secured to the contact spring 23 which passes freely through a hole in its mate spring 24. Normally the contacts of springs 23 and 24 are in engagement. Cam wheel I4 also cooperates with a stud 25 secured to the spring 26 which spring mates with a spring 21 and is normally out of contact therewith.

The active contact springs 28 and 3U are normally in engagement with their mate springs 29 and 3| and are interconnected by the stud 32 of insulating material staked thereto and passing freely through holes in springs 23 and 3|. The active spring 33 is normally in engagement with its mate spring 34 and has staked thereto a stud 35 which passes freely through a hole in spring S4 into engagement with the inner surface of the end oi' armature 5. The upper end of stud 35 is positioned for engagement with the lower end of stud 32 so that when the armature is attracted, the stud 35 is moved to operate spring 33 and by its enga gement with stud 32 also operates springs 23 and 33. The active contact spring 35 cooperates with a back contact spring 38 with whichv it is normally engaged and with a front contact spring 31 and has staked thereto an insulating stud 33 which extends freely through a hole in spring 38. Positioned immediately below the lower end of stud 39 is a stud 44 which is staked to spring 26 and passes freely through a hole in spring 2l. A stud 4I is secured to the armature with its upper end positioned beneath the lower end of stud 43 whereby when the armature is attracted the stud 4I engages the stud 43 to operate spring 23 and stud 4) engages stud 39 to operate spring 36.

Having now described the structiu'e of the improved relay, its application to a telephone system will be discussed. Referring rst to Fig. 3, a subscribers substation 42 is schematically disclosed which is connected over the tip line conductor 43 and the ring line conductor 44 to terminals appearing in the bank of a line nder 45, schematically illustrated by the set of brushes, and also to terminals of terminal set 45 of a connector bank. Normally the cam wheels and contact springs are in the condition illustrated in Fig. 3. lt will now be assumed that the subscriber at substation 42 initiates a call by removing the receiver from the switchhook whereupon a circuit is established from ground through battery 4l, the upper winding of relay coil 4 over spring 353 and its back contact spring 38, tip conductor 43 over the substation loop, ring conductor 44, spring 33 and its mate spring 34, through the lower winding of coil 4 to ground. The relay windings are thereby energized and attract the armature 5.

By the movement of the armature to its fully attracted position as disclosed in Fig. 4, the pawl I8 secured to the armature advances the ratchet wheel I3 one tooth or one step. At its half step position the stud Z3 rides up upon the top of a tooth of the cam wheel and causes the engagement of spring 2| to which the stud is secured with spring 23 thereby establishing a local operating circuit for the windings of the relay extending from the ungrounded terminal of battery 4'! through the upper winding of the coil 4 over springs 29 and 2| through the lower winding of the coil 4 to the grounded terminal of the battery. This circuit insures that the windings will be maintained energized until the armature is fully attracted since upon the movement of the armature, the stud 35 engaged thereby will open the line loop operating circuit for the relay windings by moving spring 33 out of engagement with spring 34.

When the armature reaches its fully attracted position as illustrated in Fig. 4, the stud 23 drops down into the depression between two teeth of cam wheel I3; the upper end of stud 35 is engaged against the lower end of stud 32 to move springs 28 and 3|] out of engagement with their mate springs 29 and 3|; a tooth of cam wheel I4 depresses stud 22 to move spring 23 out of engagement with spring 24 and a second tooth of cam wheel I4 raises stud 25 to engage spring 25 with spring 2l and the movement of spring 25 engages its stud 43 with stud 39 to disengage spring 3S from spring 3B and to engage it with spring 3l. Upon the disengagement of springs 35 and 33, the previously traced connection of the upper winding of coil 4 to tip conductor 43 is opened and since the connection of the lower winding of coil 4 to ring conductor 44 was opened upon the disengagement of springs 33 and 34, both windings of the coil 4 are now disconnected from the line loop. Since also springs 2| and 23 are at this time out of engagement and the local energizing circuit through the relay windings is therefore opened, the relay releases its armature. With spring 36 now held in engagement with spring 3l by a tooth of cam wheel I4, the sleeve terminal of the calling line is marked with battery potential to indicate to the line finders having access thereto that the line is in a calling condition. This potential is applied from battery 41 through the upper winding of coil 4 over springs 36 and 31 to terminal 48. Over springs 26 and 21 which are held in engagement by a tooth of cam wheel I4, the line-finder start circuit 49 is prepared.

Upon the release of the relay armature as just described, the cam wheels retain their previous settings but the armature permits springs 28, 30 and 33 to restore so that the circuit assumes the condition illustrated in Fig. 5. With spring 30 now in engagement with spring 3I and springs 26 and 21 still held in engagement by a tooth of cam wheel I4, the line-finder start circuit is completed from ground over springs 3l and 3D and over springs 21 and 26 whereupon in the well-known manner an idle line finder is started in search of the calling line. It will be assumed that the line finder indicated by the numeral 45 is started and that, therefore, when its test brush 50 encounters sleeve terminal 48 of the line a circuit is established from ground on 'brush 53 over terminal 48, springs 31 and 36, through the upper winding of coil 4 to battery, thereby causing the attraction of the relay armature to advance the cam wheels another step. The circuit now has assumed the condition illustrated in Fig. 6.

It will be noted that the movement of the armature has now disengaged springs, 28, 36 and 33 from their mate springs whereby the start circuit previously traced is opened at springs 3i) and 3|.

In the half step position of cam wheel I3, springs 2| and 29 are momentarily engaged to close the local operating circuit through the windings of coil 4 as previously traced, but this circuit is not necessary at this time, since the upper winding of coil 4 is maintained steadily energized over the circuit previously traced to ground at the test brush 5i). The second step advance of cam wheel I4 permits spring 23 to reengage spring 24 and moves its tooth from under the end of stud 25, but springs 26 and 36 are not permitted to restore since they are now held in their operated positions by stud 4I secured to the armature which is now positioned with its up-per end in engagement with the lower end of stud 40. The relay armature is now maintained in its attracted .position by the L energization of the upper winding of coil 4 until the connection is released and ground is removed from the test brush 50. With the springs 33 and 34 disengaged and springs 33 and 38 also disengaged, both windings of the coil 4 are disconnected from the line conductors. When ground is disconnected from test brush 50, the upper winding of coil 4 becomes deenergized and the armature releases to restore the circuit to its normal position illustrated in Fig. 3.

Should the line be seized on an incoming call by the engagement of the brushes of a connector switch with the connector bank multiple terminal set 46 of the line and the line be at the time idle, the circuit will be in the condition illustrated in Fig. 3. A circuit will thereupon be established from ground in the connector switch over the sleeve terminal 5I through resistance 52 to battery and in parallel with resistance 52 over springs 2S and 29 or springs 23 and 24 and through the upper winding of coil 4 to battery, whereupon the relay armature will be attracted to advance the cam wheels one step and to move the springs into the position disclosed in Fig. 4. As previously described, in the half step position of cam wheel TII I3, the springs 2I and 29 are engaged to close the local operating circuit through the windings of coil 4 to insure that the armature will be fully attracted, since the armature in moving to its fully attracted position disengages springs 28 and 29 and the one step advance of cam wheel I4 disengages springs 23 and 24 and, therefore, opens the initial operating circuit through the upper winding of coil 4. When the armature reaches its fully attracted position with springs 28 and 29 disengaged and springs 23 and 24 disengaged, the upper winding of coil 4 becomes deenergized and the armature restores. The circuit is now in the condition illustrated in Fig. 5 in which the previously traced line-under start circuit 49 is Closed from ground over springs 3I-30 and springs 21 and 26. This circuit is, however, only momentarily closed since the energizing circuit through the upper winding of coil 4 is immediately closed from ground in the connector switch over terminal 5I and springs 28 and 29 and the relay armature is again attracted to disengage springs 30 and 3I and to advance the cam wheels a second step. To insure that the line-finder start relay will not operate upon this momentary closure of the start circuit 49 to start a line lnder which is not required on an incoming call, the start relay may be made slightly slow to operate.

The circuit is now in the condition illustrated in Fig. 6 and the relay is maintained operated until the connection is released by the energization of its upper winding from ground applied at the connector over terminal 5I, springs 23 and 24 which engaged upon the second step advance of cam wheel I4, through the upper winding of coil 4. When the connection is released, the relay circuit restores to the condition illustrated in Fig. 3. Had the line been busy because of a call initiated therefrom, in which case the circuit would be in the condition illustrated in Fig. 6, the test brush of the connector switch would encounter busy ground on the test terminal 5I applied thereto over engaged springs 23 and 24, engaged springs 36 and 31, terminal 48 and brush of the line nder.

While the invention has been disclosed in connection with a line circuit terminating in the bank of a line nder, it will be obvious that the line could be a line of a manual exchange system in which the circuit closed over the start conductor 49 could control the lighting of a line lamp and the relay would be responsive to the seizure of the line by an operator to extinguish such line lamp.

What is claimed is:

l. A relay having a core, windings thereon, an armature cooperating with said core, sets of springs having contacts operable by said armature, a rst energizing circuit for said windings extending over normally closed contacts of certain of said springs, means controlled by the first energization of said windings over said circuit to operate certain of said springs to disconnect said windings from said circuit and to connect one of said windings to a second operating circuit, means operative upon the deenergization of said windings to operate certain of said springs to close a signaling circuit and means operative upon the reenergization of said one winding over said second operating circuit to operate certain of said springs to open said signaling circuit, said winding becoming deenergized upon the subsequent opening of said second operating circuit to restore all springs to their normal condition whereby said windings are reconnected to said rst operating circuit.

2. A combined line and cut-off relay having a core, windings thereon, an armature cooperating with said core, sets of springs having contacts operable by said armature, means controlled by a rst energization of both windings over a line loop to operate certain of said springs to disconnect said windings from said loop, to momentarily connect said windings in a local operating circuit, to prepare a signaling circuit and to prepare a second operating circuit through one of said windings, means operative in response to the deenergization of said windings upon the opening of said local operating circuit to operate certain or said springs to close said signaling circuit and means operable upon the reenergization of said one winding over said second operating circuit to operate certain of said springs to open said signaling circuit, said one winding becoming deenergized upon the opening of said second operating circuit to restore all springs to their normal condition whereby said windings become reconnected to the line loop.

3. A combined line and cut-off relay having a core, windings thereon, an armature cooperating with said core, first sets of contact springs operable by said armature over which said windings are normally connected to a line loop, a rotatable shaft having carn wheels thereon, a pawl secured to said armature whereby said shaft is advanced step by step upon successive actuations of said armature, a second set of contact springs momentarily operable during the rst step advance of one of said cam wheels by the attraction of said armature in response to the closure of the line loop to close a local energizing circuit for said windings, a third set of Contact springs operable by the first step advance oi' said other cam wheel for preparing a signaling circuit, said armature in its fully attracted position operating said nrst sets of springs to disconnect said windings from said line loop whereby upon the opening of said momentarily operated second set of springs said windings are deenergized to release said armature, a fourth set of contact springs closable upon the release of said armature to close said prepared signaling circuit and a second operating circuit for one of said windings prepared over one of said rst sets of springs by the iirst step advance of said other cam wheel whereby upon the closure of said second circuit andl the attraction of said armature said cam wheels are advanced a second step, said fourth set of springs are opened to disrupt said signaling circuit and one of said first sets of springs is held operated to maintain said second operating circuit closed.

4. A combined line and cut-off relay having a core, windings thereon, an armature cooperating with said core, sets of springs having contacts operable by said armature, said windings being normally connected to a line loop over certain o1' said springs and one winding being normally connected to a second operating circuit over other of said springs, means controlled by a first energization of said one winding over said second operating circuit to operate certain of said springs to disconnect said windings from the line loop and from said second operating circuit whereby said one winding becomes deenergized to operate other of said springs to reconnect said one winding to said second operating circuit whereupon said one winding again becomes energized to operate springs whereby it is maintained energized so long as said second operating circuit is maintained closed.

5. A combined line and cut-off relay having a core, windings thereon, an armature cooperating with said core, rst sets of contact springs operable by said armature over which said windings are normally connected to a line loop, an operating circuit for one winding of said relay extending in parallel over second and third sets of contact springs, a rotatable shaft having a cam wheel thereon, a pawl secured to said armature whereby said shaft is advanced step by step upon successive attractions of said armature and means for closing said operating circuit whereby said armature is attracted to open said first sets oi springs to disconnect said windings from the line loop7 to open said second set of contact springs and to advance said cam wheel one step to open said third set of springs, said winding thereupon deenergizing to release said armature whereby said second set of springs is reclosed to reestablish said operating circuit whereupon said armature is reattracted to advance said cam wheel a second step to reclose said third set 0i springs, said operating circuit then remaining closed until opened by said means.

RAY S. WILBUR.

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