US2122112A - Centralized traffic controlling system for railroads - Google Patents

Description

June 28 1938.

W. T. POWELL CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR-RAILROADS Filed May 23, 1934 2 Sheets-Sheet l w n E on n v mum ATTORNEY June 28, 1938. w. T. POWELL 2932,1152

CENTRALIZED TRAFFIC CONTRbI-JLING SYSTEM FOR RAILROADS Filed May 23, 1934 2 Sheets-Sheet 2 Egg u a 5mm Patented June 28, 1938 UNlTED STATES,

CENTRAIJZED TRAFFIG CONTROLLING SYSTEM FOR RAILROADS C Winfred T. Powell, Rochester, -N. Y., assignor to General Railway Signal Company, Rochester,

Application May 23,

9 Claims.

This invention relates to centralized traffic controlling Systems for railroads and it more particularly pertains to the means employed for interrelating the operation of a plurality of trafiic controlling devices with the operation of the communication part of such a system.

In that type of centralized traffic controlling system where a communication system of the station selective type is employed, control impulses are transmitted from the central control ofiice to the several field stations during separate operating cycles. Similarly, indication impulses are transmitted to the control ofiice in accordance with the positions of the various traffic controlling devices at the several field stations and these indication impulses are transmitted to the control ofiice, one station for each operating cycle. Since the present invention is directed to the transmission of controls from the control oilice to the various field stations, the indication portion of the centralized traific controlling system is not shown. Likewise, since the present invention is directed to the selection of the code determining relays for controlling the application of the code combinations to the control line circuit by means of station buttons or keys, none of the field station apparatus is shown and only that part of the control ofiice apparatus is illustrated which relates to the interconnection of the keys with the code determining relays and the selection of the code combinations by these code determining relays during the various steps of an operating cycle.

In centralized traffic controlling systems employing the well known coded type station selecting arrangement, the control office operator is provided with a key board containing, in addition to the switch machine and signal control levers, a set of station keys ordinarily comprising one key for each station. The purpose of the station keys is to control thesetting up of the proper code combinations for selecting the stations at which controls are to be governed. In the operation of such a system the actuation of a sta- F tion key (or starting button as it is sometimes termed) controls the actuation of a code determining relay which in turn selects the particular code combination for selecting the desired station. It is convenient to be able to cross-connect the circuits selected by the code determining relays so that the arrangement of code combinations for the various stations may be changed at any time. The code determining relays have selecting contacts'which, by means of the synchronous stepping device, associate the various control levers with the system at the different steps of an operating cycle so that the line circuit leading to the various stations can be impulsed with code impulses in accordance with 1934, Serial No. 727,147

the station to be selected and the controls to be effected at the selected station.

In view of the above requirements it has previously been the practice to provide a single starting button or station key for each station connected to the system and also to provide a separate code determining relay for each station connected to the system. Where a large number of stations are involved, the number of code determining or station relays and the number of station keys becomes quite an item and therefore an important feature of the present invention relates to the provision of a number of station keys and a number of station or code determining relays which is considerably less than the number of stations involved. In accordance with the present invention the amount of space required for the station keys and the amount of space for the code determining relays is considerably reduced from that previously employed.

Other objects, purposes and characteristic fea- .tures of the present invention will be in part obvious from the accompanying drawings and in part pointed out as the description of the invention progresses.

In describing the invention in detail reference will be made to the accompanying drawings in which:--

Fig. 1 illustrates a preferred arrangement of the station keys arranged in a vertical row of three and a horizontal row of three as a typical example.

Fig. 2 illustrates the circuit arrangement of the six keys illustrated in Fig. 1, together with the six associated code determining relays,

Fig. 3 illustrates a modified arrangement in ,which nine individual keys, one for each station are used, with the circuits so arranged that six code determining relays are provided,

Fig. 4 illustrates the circuit arrangements whereby the communication line circuit is impulsed on the various steps of an operating cycle in accordance with the code jumper connections and the positions of certain control levers as selected by various combinations of code determining relays.

In the preferred form of the invention the station keys are arranged in two rows, a horizontal row and a Vertical row as illustrated in Fig. 1. A chart or diagram containing the station numbers (or station names) is provided as illustrated in this figure, so related to the key arrangement that the operator in selecting a station locates the number or name of the station on the chart and then follows the vertical column to the top and actuates the key at the top of this column. The operator likewise follows the horizontal column in which the station number is located to the left and then actuates the key at the end of this column. This operation of two keys causes the operation of the two corresponding code detertypical example of the arrangement for selecting nine stations by means of six keys. It will be understood that this plan maybe enlarged to 1 take care of any desired number of stations. For

example, in a system of stations'therewill be five keys in the horizontal row and five keys in the vertical row so that it is merely necessary to actuate the keys corresponding to the horizontal and vertical rows in which the required station number or name is located in order to set' up a call to a given. station. In order to further reduce the space required,,one or both sets of keys may be arranged in two rows staggered with respect to each other. Furthermore, in order to assist the operator the key board may be so laid out when the system is installed that thosestations morefrequently called will be located near the upper and left boundaries of the diagram so that the distance from thepoint which identifies the station desired to the two keys to be operated is reduced for those stations most frequently selected. V V v In order to indicate to the operator which station is being selected, a lamp is associated with each key and thelighting of a combination of two of these lampsmake's it a simple matter to determine the station being selected at any time. For example, if lamps 4L and 3L are burning the operator only needs to refer back in the horizontal 'row associated with lamp 4L to the vertical row associated with lamp 3L which indicates that Station No. 3 is being selected.

A centralized traflic controlling system in which the present invention is particularly useful comprises a control ofiice located at a convenient point and a plurality of field stations located throughout the territory under the control of theoperator. The communication system connecting the control office with the field stations may be of any suitable type, but for convenience in describing the present invention, it is assumed that such a communication systemis of the station selective, duplex, coded type as disclosed, for example, in the patentto T. J. Judge et, al., 2,082,544, dated June '1', 1937. It is to be underderstood however that the specific formof communication system is not essential to the functioning of the meansembodying the present invention, but rather the means embodying the present invention may be considered as an adjunct to any communication system.

The invention may now be more fully understood by reference to the following detailed description when read in connection with-theacpanying drawings. I Ojficc equipment.In the communication system contemplated asused in connection withthe present invention, a seriesstepping or control line circuit connects the control ofi'ice with-"the several field stations and receivescurrentimpulses from a suitable source of energysuch as battery CB'locatedin the control ofiice and illustrated'in the upper right-hand portion of Fig.4. The line circuit is illustrated in the upper right hand portion of Fig. 4 by reference characters l0 and I2 which correspond to like reference characters in the above mentioned application, Ser. No. 640,062. The series message or indication'line circuit shown in this prior application has been omitted from the present disclosure since it is immaterial to an understanding of the present invention.- r r Biased-to-neutral polar relay F is connected in the line circuit and is actuated to its right and left hand positions in response to the application their character. Impulse relay EP corresponds to the EP relay in the above mentioned prior application and is-for the purpose of impulsing the line circuit. Slow acting relays SA and SAP correspond to relays SAjand 2SA respectively of the abovementioned application, these relays being picked up at the beginning of each cycle and dropped at the end of each cycle. Positive code determining relay PC and negative code determining relay NC select the characters of the impulses applied to the line circuit in accordance with the combination of CD relays picked up, as determined by the code jumper and control lever connections. Y

Stepping relays l V to 6V inclusive are for the purpose of marking ofi the diiferent steps of the cycle in the control o'ffice. While the detailed circuits of this stepping relay bank are not shown, they may be of any suitable arrangement such for example as the circuits disclosed in the prior application of T. J. Judge, Ser. No. 635,062, corresponding to British Patent 419,401. Cycle controlling relay C corresponds to a similar relay in the above mentioned Patent No. 2,082,544, this relay being picked up only during a control cycle. Code determining relays lCD'to 6CD inclusive are picked up in response to the actuation of the proper station keys and these relays effect the selection of the PC and NC relays for applying and impulses respectively to the line circuit as will be explained in detail later. Relays IG and 2G are guard relays for the purpose of Preventing the subsequent energiz ation of a CD relay as long as a previously actuated CD relay is energized in the corresponding horizontal and vertical groups respectively.

Suitable code jumpers are provided in order to change the code combination applied to the line circuit with the various combinations of CD relays in their actuated positions. These code jumpers are indicated in the left hand portion of Fig. 4 and it will be understood that theconductors leading from the CD relay contacts may be cross-connectedto either the PC or NC bus of Fig. 4 and it will be understood that these levers are associated with corresponding stations of the nine indicated in the present example. It will be understood that additional levers, such as signal levers, may be providedand selected on a successive step (for example, step 6) of the communication system.

Instead of showing the actual connections to terminals of a suitable source of potential, symbols have been employed torepresent such terminals. The symbols and designate the opposite terminals of a suitable source of potential and the circuits with which these symbols are employed always have current flowing .in the same direction. As above mentioned, the lamps are for the purpose of identifying a station which is being selected during any particular cycle of operations and these lamps may or may not be (ill used as desired. Cancelling key CK shown in Fig. 2 is provided for the purpose of cancelling a registration set up on the CD relays at any time during the cycle. This key is useful in restoring the CD relays to normal in the event that the operator actuates a wrong starting button.

It is believed that the operation and usefulness of the present-invention will be best understood by further description being set forth from the standpoint of operation.

Operation Normal conditions-With the system in its normal condition all of the relays and lamps are deenergized. In order that the communication system may be initiated into operation from the control ofiice, the upper windings of the CD relays are connected to potential through back contacts of the guard relays as indicated in Fig. 2 so that the actuation of any starting button will pick up the corresponding CD relay.

The lower set of front contacts of the CD relays connected in multiple as shown in the lower portion of Fig. 4, is for the purpose of initiating the system into a cycle of operations in response to the picking up of any one of these CD relays.

Such initiation is not shown in detail since it is immaterial for an understanding of the present invention. The above mentioned prior application, Ser. No. 640,062 indicates in detail how relay C is picked up and the system is initiated when any CD relay of the group is energized. Although the multiple contacts in the above mentioned prior application are associated with CH relays it will be understood that the system can as well be initiated by associating these contacts with the CD relays.

Operation of Figs. 1 and 2.-With the system in its normal condition it may be manually initiated into a cycle of operations for the transmission of controls to any desired station. When such a cycle of operation is desired, the operator first positions the control levers associated with the desired station and then actuates the starting buttons associated with this station.

It is believed that the following code table will be helpful in obtaining an understanding of the operation of the present invention. The nine stations which may be selected are listed in the first column, the code combinations for selecting these stations are listed in the second column and the particular CD relays which are picked up to provide these code combinations are listed in the third column.

Code table Code OD relays up It will first be assumed that the operator desires to set up a call to the station whose name or number is at the intersection of the first vertical column and the first horizontal column of Fig. 1. vThis is assumed to be Station No. 1 and to select this station the operator will depress keys lSB and iSB. Referring to Fig. 2, the actuation of key ISB closes a-circuit for picking up relay ICD which extends from front contact 20 of key ISB, upper winding of relay ICD and back contact 2| of relay IIG, to Relay ICD closes a stick circuit for itself extending from back contact 22 of relay SAP, back contact of key CK, winding of relay IG, front contact 23 and lower winding of relay lCD, to The opening of back contact 28 of button ISB disconnects potential from the other buttons in the horizontal row so that they are ineffective to operate any other CD relay as long as button ISB is actuated. Relay ICDcloses a circuit through its front contact 24 which lights lamp lL. The stick circuit for relay ICD includes the winding of relay IG, which relay opens its back contact 2| to remove the potential from the pick up windings of all CD relays in the horizontal row so that none of these relays can be actuated as long as relay I CD is stuck up.

The actuation of button iSB closes a circuit for picking up relay @CD which extends from front contact 25 of button 4S3, upper winding of relay 4CD and back contact 26 of relay 2G, to Relay 4CD closes a stick circuit for itself extending from back contact 22 of relay SAP, back contact of key CK, winding of relay 2G, front contact 21 and lower winding of relay 4CD, to The opening of back contact 25 of button iSB removes potential from all other starting buttons in the vertical row so that they are rendered ineffective to pick up-their associated CD relays in the event that another button in this row is actuated. Relay 4CD closes a circuit through its front contact 28 for lighting lamp AL. The stick circuit through the lower winding of relay 4CD extends through I and horizontal rows in which these lamps are 1 located is the No. 1 station designation.

The above described stick circuits for the CD relays extend to through fromback contact 22 of relay SAP and, since relay SA closes its front contact 29 before relay SAP opens its back contact 22 at-the beginning of a cycle, these stick circuits are maintained energized throughout the cycle. At the end of the cycle relay SA opens its front contact 29 before relay SAP closes its back contact 22; which is effective to deenergize the stick circuits of the CD relays and drop those which are picked up. It will also be understood that when these stick circuits are'deenergized at'the end of a cycle, the IG and 2G relays are deenergized which applies" potential to the pick up windings of all CD relays so that the next pair to be used can be picked up.

In the event that Station No. 2 is to be selected keys 2SB and 45B are actuated. Key lSB accomplishes the same result as previously described. Key ZSB closes a circuit for picking up relay 2CD which extends from back contact 20 of key ISB, front contact 39 of key ZSB, upper winding of relay 2CD and back contact 28 of relay lG, to Relay 2CD closes an obvious stick circuit for itself by way of its front contact 3i. Relay 2CD closes a circuit for energizing lamp 2L by way of its front contact 32.

In the event that Station No. 3 is to be selected buttons 3SB and lSB are actuated. Key 4SB accomplishes the same result as-previously described. Key 383 closes a circuit; for picking up relay 3CD which extends from back contacts 20 and SE! of buttons ISB and 283 respectively, front contact 4% of button 3SB, upper winding of relay 3CD and back contact 2| of relay lG, to Relay 3CD closes an obvious stick circuit for itself at its front contact 4! and at its front contact 42 it closes a circuit for lighting lamp 3L. The above three examples indicate how Relays l and 4, 2 and 4, 3 and 4 are picked up in response to the actuation of corresponding starting buttons when Stations 1, 2 and 3 respectively are to be selected.

In the event that Station 4 is to be selected buttons lSB and 5SB will be actuated. Button ISB causes relay i CD to be picked up as previously described. Button BSB closes a circuit for picking up relay 5CD which extends from back contact 25 of button lSB, front contact 33 of button ESB, upper winding of relay 5CD and back contact 26 of relay 2G, to Relay 5CD closes an obvious stick circuit for itself at its front contact 34 and at its front contact 35 it closes a circuit for lighting lamp 5L.

In the event that Station 5 is to be selected buttons ZSB and 5813 will be actuated. The actuation of these two buttons causes relays 2CD and 5CD to be picked up by means of circuits previously explained.

In the event that Station No. 6 is to be selected buttons '3SB and 55B are-actuated which cause relays 3CD and 5CD to be picked up by means of circuits previously'explained. It will thus be seen that CD Relays l and 5, 2 and 5, 3 and 5 are picked up in response to the actuations of the corresponding buttons When- Stations 4, 5 and 6 respectively are to be selected.

In the event that Station '1 is to be selected buttons ISB and EiSB are actuated. ISB causes relay ICD to be picked up as previously described. A circuit is closed for picking up relay 6CD which extends from back contacts 25 and 33 of buttons lSB and 58B respectively, front contact 3 of button ESE, upper winding of relay GOD and back contact 26 of relay 2G, to Relay' 6CD closes an obvious stick circuit for itself at its front contact 44 and at its front contact i5 it closes a circuit for lighting lamp 6L.

In the event that Station 8 is to be selected buttons ZSB and ESB are actuated which cause relays 2CD and 6CD to be picked up over cir cuits previously described.

In the event that Station 9 is to be selected buttons ESB and GSB are actuated which cause relays 3CD and 5CD to be picked up by means of circuits previously described. It will thus be seen that CD Relays 1 and 6, 2 and 6; 3 and 6 are picked up in response to the actuation of corresponding starting buttons when Stations 7, 8 and 9 respectively are to be selected.

In the event that the operator desires to cancel the result of actuating a starting button it is only necessary to momentarily actuate cancelling key CK which disconnects potential from the stick circuits of the CD relays, allowing these relays and the guard relays to be released, after which another registration can be made by again operating the starting buttons. It will be understood that additional CD relays in the horizontal row, which includes relays lCD, 2CD and 3CD, may be provided when additional horizontal row starting buttons are provided and additional CD relays in the Vertical row, including the relays. 4CD, 5CD and 6CD, may be provided to correspond with additional starting buttons'in the vertical row when the size of the system is increased.

Fig. 3 modificatitm.The modification shown in Fig. 3 functions to operate the CD relays in pairs as disclosed in connection with Fig. 2, except that an individual key or starting button is provided for each station. In this modification the operation of button ISB closes circuits for picking up relays [CD and 4CD which are the same relays picked up in the previous description for selecting Station No. 1. Button ZSB picks up relays 2CD and 4CD. Button 3SB picks up relays SOD and ilCD. Button lSB picks up relays iCD and 5CD. Button ESSB picks up relays ECU and 5CD. Button BSB picks up relays 3CD and 5CD. Button 'ISB picks up relays lCD and 6CD. Button BSB picks up relays 2CD and 5CD. Button QSBi picks up relays 3CD and 6CD.

It is not believed necessary to point out the detailed circuits of this modification. It will be understood that the stick circuits including the lower windings of the CD relays in series with the G relay windings and the cancelling key are exactly the same as shown in connection with the CD relays of Fig. 2. In other words, the only diiference in the Fig. 3 modification is the pick up circuits connected to individual starting buttons instead of to a combination of two starting buttons.

potential is connected to the contact fingers of button ISB whose back contacts extend to the contact fingers of button ZSB. The back contacts of each button are likewise wired to the contact fingers of the next button of higher order. This is similar to the circuit wiring of the buttons of Fig. 2, in that the operation of any button nearer the end of the circuit disables all buttons to the right of the one which is actuated.

The actuation of button ISB closes a circuit for picking up relay lCD which extends from front contact Hill of button iSB upper winding of relay K31) and back contact till of relay IG, to A circuit is closed for picking up'relay 4CD which extends from front contact E02 of button ISB, upper winding of relay 4CD and back contact I03 of relay 2G, to The operation, of the other combinations of the CD relays will be obvious by referring to the above code table and an examination of the circuits of Fig. 3.

Operation of Fig. 4.Relays ICD to 6CD inclusive of either Fig. 2 or Fig. 3 are shown in Fig. 4 with the circuits which they control. The above description of Figs. 2 and 3 indicates how these CD relays are controlled and the following description of Fig. 4 will indicate how the circuits are controlled by the CD relays. As above mentioned the lower front contact on each CD relay (all of which are connected in multiple) is for the purpose of initiating the system into its cycle of operations in response to the actuation of a starting button or buttons.

Station No. 1.-As above described relays ICD and 4CD are picked up when Station No. l. is to be selected. Referring to the code table it will be seen that the code combination for selecting this station is Recalling that relay C is picked up during each control cycle, the first step (relay iV picked up)) closes a circuit for picking up relay PC which extends from front contact 59 of relay C, back contacts 5!, 52, 53, 54 and 55 of relays 5V, 5V, 4V, 3V and 2V respectively, front contact 56 of F to line conductor ill and through the stationequipment to return conductor l2, front contact 13 of relay PC and back contact M of relay NC to the terminal of battery CB.

When relay 2V is picked up on the second step a circuit is closed for picking up relay PC for providing the second impulse. This pick up circuit extends from front contact 56 of relay back contacts 52, 53 and 54 of relays 6V, 5V, 4V and 3V respectively, front contact 55 of relay 2V, front contact 63 of relay ICD, back contact 6! of relay 6CD, code jumper 64, PC bus and winding of relay PC, to The second impulse in the line is thus determined by reason of the picking up of relay PC.

The third impulse in the line circuit is because relay PC is picked up on the third step over a circuit extending through front contact 54 of relay 3V, front contact 65 of relay ICD, front contact 66 of relay 4CD, code jumper ,6], PC bus and winding of relay PC, to

The fourth impulse applied to the line circuit is because relay PC picks up when the fourth step is taken over a circuit including front contact 53 of relay 4V, front contact 51 of relay lCD, back contact 58 of relay 5CD, code jumper 59, PC bus and winding of relay PC, to I It is believed that the above example indicates how the line circuit is impulsed with the four characteristic impulses in accordance with the selection of relay PC at each of the first four steps of the cycle. In view of the above description the following discussion will be limited to merely pointing out the circuits for picking up the PC and NC relays in accordance with the various code combinations. It will be obvious that, with relay PC down and with relay NC picked up, the terminal of battery CB is extended through front contact 14 of relay NC, back contact ll of relay PC, back contact 12 of relay EP and winding of relay F to line conductor it for providing a impulse.

When Station No. 2 is to be selected relays 2CD and 4CD are picked up causing code to be applied to the line circuit. Relay PC is picked up on the first step to provide a impulse over a circuit extending through front contact 56 of relay IV, front contact 16 of relay 2CD, code jumper 62, PC bus and winding of relay PC, to

Relay PC is picked up on the second step to apply a impulse to the line circuit over a circuit extending through front contact 55 of relay 2V, front contact 15 of relay 2CD, front contact ll of relay 4CD, jumper I8, PC bus and winding of relay PC, to

Relay PC is picked up on the third step to provide a impulse in the line circuit over a circuit extending through front contact 56 of relay 3V, front contact 68 of relay 2CD, back contact 69 of relay 6CD, jumper 19, PC bus and winding of relay PC, to

Relay NC is picked up on the fourth step to apply a impulse to the line circuit over a circuit extending through front contact 53 of relay 4V, front contact 86 of relay 2CD, back contact 8| of relay 5CD, jumper 82, NC bus and winding of relay NC, to

Selection of Station No. 3.This station responds to code and relays 3CD and 4CD are picked up. Relay PC is picked up on the first step to apply a impulse to the line circuit over a circuit extending through front contact 56 of relay IV, front contact 83 of relay 3CD, back contact 84 of relay 6CD, jumper 85, PC bus and winding of relay PC, to

Relay PC is picked up on the second step to apply a impulse to the line over a circuit extending through front contact 55 of relay 2V, front contact 86 of relay 3CD, back contact 81 of relay 5CD, jumper 88, PC bus and winding of relay PC, to

Relay NC is picked up onthe third step to apply a impulse to the line over a circuit extending through front contact 54 of relay 3V, front contact 89 of relay 3CD, front contact 96 of relay 6CD, jumper 9|, NC bus and winding of relay NC, to

Relay PC is picked up on the fourth step to apply a impulse to the line over a circuit extending through front contact 53 of relay 4V, front contact 92 of relay 3CD, back contact 93 of relay 5CD, jumper 94, PC bus and winding of relay PC, to

Selection of Station No. 4.Relays ICD and 5CD are picked up to provide code Relay PC is picked up at the first step to apply a impulse to the line over a circuit extending through front contact 56 of relay IV, front contact 66 of relay ICD, jumper 62, PC bus and winding of relay PC, to

Relay PC is picked up on the second step to apply a impulse to the line over a circuit extending through front contact 55 of relay 2V, front contact 63 of relay ICD, back contact 6| of relay 6CD, jumper 64, PC bus and winding of relay PC, to

Relay NC is picked up on the third step to apply a impulse to the line over a circuit extending through front contact 54 of relay 3V, front contact 65 of relay ICD, back contact 66 of relay 4CD, jumper 95, NC bus and winding of relay NC, to

Relay NC is picked up on the fourth step to apply a impulse to the line over a circuit extending through front contact 53 of relay 4V, front contact 51 of relay ICD, front contact 58 of relay 5CD, jumper 96, NC bus and winding of relay NC, to

Selection of Station No. 5.--Relays 2CD and 5CD are picked up to provide code Relay PC is picked up on the first step to apply a impulse to the line over a circuit extending through front contact 56 of relay IV, front contact E6 of relay 2CD, jumper 62, PC bus and winding of relay PC, to

Relay NC is picked up on the second step to apply a impulse to the line over a circuit extending through front contact 55 of relay 2V, front contact 15 of relay 2CD, back contact 11 of relay 4CD, jumper 91, NC bus and winding. of relay NC, to

Relay PC is picked up on the third step to apply a impulse to the line over a circuit extending through front contact 54 of relay 3V, front contact 68 of relay 2CD, back contact 69 of relay 6CD, jumper 19, PC bus and winding of relay PC, to

ply a impulse to the line over a circuit extending through front contact 53 of relay 4V,

. front contact 85 of relay 2CD, front contact 8| of relay 5CD, jumper 98, PC bus and Winding of relay PC, to

Selection of Station No. 6.-Relays 3CD and 5CD are picked up to provide code Relay PC is picked up on the first step to apply a impulse to the line over a circuit extending through front contact 56 of relay IV, front con- 7 tact 83 of relay 3CD, back contact 84 of relay 6CD, jumper 85, PC bus and winding of relay PC, to

Relay NC is picked up on the second step to apply a impulse to the line over a circuit extending through front contact 55 of relay 2V, front contact 86 of relay 3CD, front contact 8'! of relay 5CD, jumper 99, NC bus and winding of relay NC, to

Relay PC is picked up on the third step to apply a impulse to the line over a circuit extending through front contact 54 of relay 3V,

front contact 89 of relay 3CD, back contact 9 of relay 4CD, jumper 49, PC bus and winding of relay PC, to

Relay NC is picked up on the fourth step to apply a impulse to the line over a circuit extending through front contact '53 of relay 4V, front contact 92 of relay 3CD, front contact 93 of relay CD, jumper 48, NC bus and winding of q relay NC, to-

Selection of Station No. 7.Relays ICD and 6CD are picked up to provide code Relay PC is picked up on the first step to apply a impulse to the line over a circuit extending through front contact 56 of relay IV, front contact 60 of relay ICD, jumper 62, PC bus and winding of relay PC, to

Relay NC is picked up on the second step to apply a impulse to the line over a circuit extending through front contact 55 of relay 2V, front contact 63 of relay ICD, front contact 6| of relay 6CD, jumper 41, NC bus and winding of relay NC, to

' of relay 5CD, jumper 59, PC bus and Winding of relay PC, to

Selection of Station No. 8.--Relays 2CD and 6CD are picked up to provide code Relay PC is picked up on the first step to apply a impulse to the line over a circuit extending through front contact 56 of relay IV, front contact 16 of relay 2CD, jumper 62, PC bus 7, and Winding of relay PC, to

Relay NC is picked up on the second steprto apply a impulse to the line over a circuit extending through front contact 55 of relay 2V, front contact of relay 2CD, back contact 11 of relay 4CD, jumper 91, NC bus and winding of relay NC, to

mania Relay PC is picked up 'on the fourth step to ap-j Relay NC is picked up on the third step to apply a impulse to the line over a circuit extending through front contact 54 of relay 3V, front contact 58 of relay 2CD, front contact 69 of relay 6CD, jumper 46, NC bus and winding of relay NC, to

Relay NC is picked up on the fourth step to apply a impulse to the line over a circuit ex tending through front contact 53 of relay 4V, front contact 80 of relay 2CD, back contact 8| of relay 5CD, jumper 82, NC bus and Winding of relay NC, to

Selection of Station No. 9,Relays3CD and 6CD are picked up to provide code Relay NC is picked up on the first step to apply a impulse to the line over a circuit extending through front contact 56 of relay IV, front contact 83 of relay 3CD, front contact 84 of relay 8CD, jumper 39, NC bus and winding of relay NC, to

Relay PC is picked up on the second step to apply a impulse to the line over a circuit extending through front contact 55 of relay 2V, front contact 86 of relay 3CD, back contact 8'! of relay 5CD, jumper 88, PC bus and winding of relay PC, to

Relay PC is picked up on the third step to apply a impulse to the line over a circuit extending through front contact 54 of relay 3V, front contact 89 of relay 9CD, back contact 90 of relay 4CD, jumper 49, PC bus and winding of relay PC, to

Relay PC is picked up on the fourth step to apply a impulse to the line over a circuit extending through front contact 53 of relay 4V, front contact 92 of relay 3CD, back contact 93 of relay 5CD, jumper 94, PC bus and winding of relay PC, to

The above examples indicate how the nine distinctive code combinations are applied to the line circuit in response to the selection of the PC and NC relays, by way of the code jumpers as selected by the combinations of CD relays which are picked up in response to the actuation of the starting buttons corresponding to these nine stations.

When the fifth step is taken (which is the first step after station selection), the PC and NC relays are selected in accordance with the position of the control lever associated with the station selected on the preceding steps. For example, when Station No. 1 is selected, relays ICD and 4CD are picked up and a circuit is established for I picking up relay PC extending through front contact 52 of relay 5V, front contact 36 of relay I CD, front contact 3? of relay 4CD, lever ISML in its right-hand position, PC bus and winding of relay PC, to In the event that lever ISML is in its left-hand dotted position, relay NC is energized.

Thus, the line circuit is energized with a or impulse after Station No. 1 is selected as determined by the position of lever lSML. In the same manner the line circuit may be impulsed on the next step over a circuit including a front contact 5| of relay 6V and additional contacts on relays ICD and 4CD, by way of a signal control and 6CD are picked through front contact 52 of relay 5V, front contact 53 of relay BCD and front contact I4 of relay lCD, to lever 3SlVlL.

When Station No. 4 is selected, relays ICD and 5CD are picked up so that a connection is extended to the PC or the NC relay as selected by lever iSML, over a circuit extending'through front contact 52 of relay 5V, front contact 36 of relay lCD, and front contact l5 of relay 5CD, to lever QSML.

When Station No. 5 is selected, relays 2CD and 5CD are picked up, which results in energizing relay PC or relay NC in accordance with the position of lever l'iSML, over'a circuit extending through front contact 52 of relay 5V, front contact 38 of relay 2CD and front contact l6 of relay 5CD, to lever ESML.

When Station No. 6 is selected, relays 3CD and 5CD are picked up to select the PC or the NC relay in accordance with the position of lever GSlVEL, over a circuit extending through front contact 52 of relay 5V, front contact l3 of relay BCD and front contact ll of relay 5CD, to lever iiSML.

When Station No. 7 is selected, relays ICD and 6CD are picked up to select the PC or NC relay in accordance with the position of lever TSML, over a circuit extending through front contact 52 A of relay 5V, front contact 36 of relay ICD and front contact N3 of relay 6CD, to lever ISML;

When Station No. 8 is selected, relays 2CD and 6CD are picked up to select the PC or NC relay in accordance with the position of lever 8SML, over a circuit extending through front contact 52 of relay 5V, front contact 38 of relay 2CD and front contact N3 of relay 6CD, to lever BSlVlL.

When Station No. 9 is selected, relays 3CD up to select the PC or NO relay in accordance with the position of lever BSML, over a circuit extending through front contact 52 of relay 5V, front contact l3 of relay 3CD and front contact 9 of relay 6CD, to lever SSML.

In view of the above examples it is believed obvious how additional steps may be arranged to select additional levers for each station selected, over circuits similar to those described in connection with the selection of the switch machine lever. It will be obvious that the code jumpers illustrated in Fig. 4 may be connected in any desired order for changing the combinations assumed in the above typical examples, by changing the selection of the PC and NC relays.

During each energization of the line circuit as above pointed out, relay F is actuated either to the right or to the left to close a circuit from polar contact 8 of relay F and winding of relay PP, to for energizing the FP relay. The intermittent operation of the FP relay closes a circuit through its front contact I for energizing relay SA, but since this relay is slow acting it remains picked up during the deenergized periods of the FP relay. Relay SAP is energized over a circuit including front contact 6 of relay SA, and since this relay is slow acting it remains energized throughout an operating cycle. At the end of each cycle, relays SA and SAP are dropped in sequence to momentarily deenergize the stick circuits of the CD relays shown in Fig. '2 as previously mentioned.

From the above description and by referring to the drawings, it will be obvious that the indication lamps illustrated in Fig. 1 may be provided in connection with the Fig. 3 circuit, in which individual station buttons are used, if it is desired to provide the operator with a visual indicationof the station which is being selected in this modification.

While the invention has been illustrated as embodied in certain organizations which are believed to be desirable from a practical standpoint, it will be obvious that the general principles herein disclosed are capable of embodiment in many other forms widely different from those illustrated without departing: from the spirit of the invention as defined in the following claims.

What I claim is:-

1. An impulse transmitter for transmitting variable codes, each comprising an invariable number of impulses of variable character; a lever for each code; a plurality of code forming buttons less in number than the number of codes; means controlled by said code forming buttons for causing said transmitter to transmit said codes; a plurality of code determining relays less in number than the number of codes and controlled by corresponding code forming buttons; means for interlocking said relays to prevent energization of more than a predetermined number at any one time; and means governed by a plurality of code determining relays for rendering the lever of a single code effective to cause said transmitter to transmit an impulse in addition to said invariable number, the character of said impulse being determined by the position of said lever.

2. An impulse transmitter for transmitting variable codes, each comprising an invariable number of impulses of variable character, a lever for each code; a code forming button for each code; means controlled by said code forming buttons for causing said transmitter to transmit said codes; a plurality of code determining relays less in number than the number of codes and controlled by said code forming buttons; means for interlocking said relays to prevent energization of more than a predetermined number at any one time; and means governed by a plurality of code determining relays for rendering the lever of a single code effective to cause said transmitter to transmit an impulse in addition to said invariable number, the character of said impulse being determined by the position of said lever.

3. An impulse transmitter for transmitting variable codes, each comprising an invariable number of impulses of variable character; a lever for each code; code forming buttons; means controlled by said buttons for causing said transmitter to transmit said codes; code determining relays controlled by said buttons; code indicating lamps less in number than the number of codes indicated thereby; means for interlocking said relays to prevent energization of more than a predetermined number at any one time; means governed by said code determining relays for rendering the lever of a single code effective to cause said transmitter to transmit an impulse in addition to said invariable number, the character of said impulse being de termined by the position of said lever; and means controlled by said code determining relays for selectively energizing a plurality of said lamps in combination to indicate the particular lever effective at a given time.

4. In an arrangement for controlling the operation of an impulse transmitter which transmits a plurality of distinctive codes over a line circuit, each code comprising a fixed number of impulses of selected polarities; a positive impulse relay and a negative impulse relay; a sequentially operated selector; a plurality of relay groups comprising a number of code determining relays less than the number of said codes; means for operating one of said code determining relays in each group; means controlled by the joint operation of said code determining relays for associating said selector with said impulse relays; means controlled by the sequential operation of said selector for sequentially operating said impulse relays in accordance with the code determined by the particular code determining relays operated; means controlled by the sequential operation of said impulse relays for transmitting a distinctive code over said line circuit; and means controlled by said code determining relays for causing said transmitter to transmit said codes.

5. An impulse transmitter for transmitting variable codes of polar impulses; a line circuit; a plurality of station designations arranged in rows extending in two directions at angles with each other; a first group of keys each corresponding to a row of designations extending in one direction; a second group of keys each corresponding to a row of designations extending in the other direction; groups of relays for initiating the operations incident to the transmission of different codes over said line circuit; circuit means controlled by the selective actuation of the keys in said groups for selectively operating one relay in each of said groups; means for energizing stick circuits for said relays for maintaining said relays operated; and means including contacts closed by the selective operation of the relays in said groups for transmitting separate and distinctive code combinations over said line circuit, each combination being characterized by the variation in polarity of an invariable predetermined number of impulses, and means for de-energizing said stick circuits following the transmission of a code over said line circuit.

6. An impulse transmitter for transmitting variable codes of polar impulses; a line circuit; a plurality of station designations arranged in rows extending in two directions at angles with each other; a first group of keys each corresponding to a row of designations extending in one direction; a second group of keys each corresponding to a row of designations extending in the other direction; groups of relays for initiating the operations incident to the transmission of difierent codes over said line circuit; circuit means controlled by the selective actuation of a key in each of said groups for selectively operating one relay in each of said groups; means for energizing stick circuits for said relays for maintaining said relays operated; means including contacts closed by the selective operation of the relays in said groups for transmitting separate and distinctive code combinations over said line circuit, each combination being characterized by the variation in polarity of an invariable predetermined number of impulses; interlocking circuits controlled by said keys for preventing the operation of more than one relay in a group at any one time; and means for de-energizing said stick circuits following'the' transmission of a code over said line circuit.

'7. An impulse transmitter for transmitting variable codes of polar impulses; a line circuit; a plurality of code determining relays comprising two groups, the total number of relays in the two groups being less than the number of codes determined thereby; circuit means for operating said relays in various combinations; means controlled by said relays for initiating said transmitter into operation; means including contacts closed by the joint operation of a'certain relay in each group for transmitting a first distinctive combination of coded impulses over said line circuit; means including contacts closed by the joint operation of a relay in each group either of which differs from said certain relays for transmitting a second distinctive combination of coded impulses over said line circuit, each of said combinations being characterized by the variation in polarity of an invariable number of impulses; and automatically controlled means for releasing the operated relays at the end of the operation of said transmitter.

8. An impulse transmitter for transmitting variable codes of polar impulses; a line circuit; a plurality of code determining relays comprising two groups, the total number of relays in the two groups being less than the number of codes determined thereby; means for operating and locking said relays operated in various combinations; means controlled by said relays for initiating said transmitter into-operation; means controlled by the joint operation of a certain relay in each group for transmitting a first distinctive combination of coded impulses over said line circuit; means controlled by the joint operation of a relay in each group either of which differs from said certain relays for transmitting a second distinctive combination of coded impulses over said line circuit, each of said combinations being characterized by the variation in polarity of an invariable number of impulses; automatically controlled means for releasing the operated relays at the end of the operation of said transmitter; and manually controlled means for releasing the operated relays at any point during the operation of said transmitter.

9. An impulse transmitter for transmitting variable codes of polar impulses; a line circuit; a plurality of code forming keys comprising two groups, the total number of keys in the two groups being less than the number of codes formed thereby; a plurality of code indicating devices comprising two groups, the total number of devices in the two groups being less than the number of codes indicated thereby; means controlled by the actuation of said keys for initiating said transmitter into operation; means controlled by the joint actuation of a key in each group for transmitting a distinctive code over said line circuit, each code being composed of an invariable predetermined number of impulses of variable polarity; means controlled by the actuation of said keys for energizing a device in each group whereby the code being transmitted over said line circuit is indicated; and interlocking means rendered effective upon the actuation of a key in either group for rendering all other keys of the associated group ineffective until after the transmission of the formed code, whereby only a single indicating device in each group can be simultaneously energized to indicate a particular code being transmitted.

WINFRED T. POWELL.

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