US1885784A - Automatic switch - Google Patents

Description

Nov, 1, 11932. TEES 1,885,784

AUTOMATIC SWITCH Filed March 16, 1931 2 Sheets-Sheet 1 IIFEFIE J as Erri al Tees Nov. 1, 1932.

J. E. TEES 1,885,784

AUTOMATIC SWITCH Filed March 16, 1931 2 Sheets-Sheet 2 Ellllllllli a 1211mm" IHUETI DI Ja s Erriaal Tees I Patented Nov. 1, 1932 renal.

PATE

T. ,rFlcEf JAMES EBBIGAL TEES, OF LONDON, ENGLAND; ASSIGNOR TO SIEMENS BROTHERS 86 COMPANY LIMITED, OF LONDON, ENGLAND AUTOMATIC SWITCH Application filed March 16, 1931, Serial No. 523,133, .and in Great Britain March 31, 1930.

u u o switches 1n automatic or semi-automatic telephone systems and more particularly to switches which search for a free outlet in a number of levels in succession.

Arrangements are'known in which a selector having searched all the outlets in a level is stepped to the next level and continues" its search over outlets in this level, search over successive levels continuing until a free outlet or the last outlet of the group of outlets is reached. In such a selector the last outlet in the last level that the switch is able to search, i. e. the uppermost level in a two-motion selector of a kind commonly used in automatic telephone systems, must constitute the last outlet of a group extending to that outlet. If the selector is a P. B. X. final selector and a group of P. B. X. lines commences in an upper level of the selector a limitis thus placed on the number of lines the group can accommodate without change of the subscribers directory number.

According to one feature of the present invention a selector is provided in which the size of a group of outlets is not restricted (owing to the position in the bank in which the first outlet of the group is connected) by virtue of the seleccorwipers reaching a limiting position without searching all possible outlets.

According to another feature ofthe invention a two-motion selector is provided having a group of outlets connected in several levels with means whereby, having searched over a level or successive levels containing outlets of the group and reaching the limiting position, the selector wipers are released to a normal position and are then stepped to the first level of the switch bank and searching continues over this and successive levels if there are any until a free outlet or the last outlet of the group is reached.

The invention is particularly applicable to P. B. X. final selectors serving large groups oi P. B. X. lines as it enables a large group of lines which commences in one of the upper levels of the bank to be extended beyond the last contact of the uppermost level by utilizing vacant lower levels and so avoiding a change in the directory number ofthe P. B.

In the case of large and important .pri

vate branch exchanges this is particularly desir-able and if necessary the number of a small exchange may be changed in order to acc'om modate an extension. to the more important exchange.

Large groups of outlets are generally con nected to selectors employing more than one set of wipers and associated contact banks and in the case of final selectors one method of operation is to'search over the outlets in a level available to one set of wipers and, if'no free outlet is found, search over the outlets in the same level available to another set of wipers is made, search over the several sets of outlets in successive levels continuing until a free outlet or the last outlet of the group is reached. I

t is usually arranged that a P. B. X. final selector connecting with large groups of lines responds to the tens digit to step the wipers to the level containing the first line in the group, the selector thereafter stepping automatically, the units digit being absorbed.

If, in the course of search, the last'contact in a level is reached, a relay may be operated over this contact to effect the release of the switch as regards its searching motion andby the provision of normal post contacts, com lete release to a normal position may be efiected from which position the switch is stepped to the first level, containing further contacts of the group over which it proceeds to search in the same manner as over the upper levels, the search being continued if necessary over a number of levels. Although the application of the'invention has been described with reference to a switch of the type in which the grouped contacts are arranged in horizontal levels vertically disposed, the switch wipers being stepped vertically. to a desired level and thereafter stepped over the level, it will be appreciated that it may equally be applied to any twocorresponding lines in alignment illustrate by way of example the application of the invention to a final selector for dealing with large groups of P. B. X. lines and having lines in a level. The lines of a group may 7 extend over more than one level, over which levels successive search for a tree line is made. If it is desired to increase the number oflines in a group without disturbing the numbering scheme, and the levels above those already occupied by the group are occupied by another group or the group to be enlarged already extends to thelimiting position of the switch, the overflow lines to be provided are accordingly accommodatedin the first level and may be succeeding levels assuming these to be vacant.

Normal post contact 11. are provided oppo sitethe last level. containing lines of the group before. extension the operation of which preparescircuits for the release of the switch shaft to its normal position and its restepping to the first level over which the search for a tree line continues it all the lines in the original part of the group are busy. The whole of the switch outlets may be taken up by a single group of lines in which case continuous search may be effected. The first line of a group is reached by dialling the tens digit of the first line of the group which steps the switch to a level in accordance with the digit dialled and over which and successive levels searchtakes place. For this purpose the connections marked X are made. If all the outlets'of a switchform one large group the switch may be arranged to search continuously, commencing at the first level, by substituting the connections shown in dotted lines and marked Y for those marked In the P. B. X. final selector shown there are two sets of wipers, eachbeing concerned with a separate set of bank contacts. Search is made first over one set of contacts by the appropriate wipers and then over the other set of contacts with the other set of wipers. The last contacts in a level aretherefore the last contacts of the second set of contacts. A

last contact of the first setrof each level is connected to a relay which when operated causes the switch to release to rotary normal, whereupon the second set of wipers is connected in circuit and search over the second set of contacts in the level proceeds.

In the drawings A indicates the impulse relay; B the release relay; D the answering supervisory relay; C the dialling relay; H

the test relay; F the ring cut-off relay.

Relay RN is concerned with the release as regards the rotary search. Two sets of con-- tact banks are shown, one having associated speaking wire wipers A, B and testVWiper C, the other having corresponding wipers A1, B1, C1. Contacts over which a first search is made are associated with wipers A, B and C. Relay E operates when a first search has been unsuccessfully made to connect the circuits to the second set of wipers A1, B1, C1. 'VS is a relay concerned with the re-stepping tion fContact cm is opened when release magnet ZM operates. Contact rm is closed when the rotary magnet operates.

Contactsnl, n2, as are vertical ofi-normal contacts shown in the unoperated position.

Contacts 4W1 and milare rotary off-normal contacts also shown unoperated. Contact 81 operates on the eleventh rotary step being made. Contact 11,79 is a normal post contact provided to be operated when the wiper shaft reaches a level containing the last contact of a group in an upper level and after search over this level it is required to release and re-step to the first level. V

7 Relay RN is connected to the last, i. e. eleventh contacts of the bank associated with wiper A. Relay DR- is connected to the eleventh contacts of the banks associated with wipers C and C1. i p

Eleventh contacts in the bank of wiper B1 of levels in which last lines of P. B. X. groups appear are connected to a wire in the final selector multiple andthis wire is earthed at one point thereby enabling variations in the number of levels in a group to be made readily.

The selector is found disengaged by reason of the incoming test wire 0 being unearthed. On the test relay of the preceding selector operating the speaking wires thereat are switched through and relay A operates in a circuit from battery over its coil (II), contacts 2m, (Z2 the 7) wire, the preceding loop wire a, contact all, coil (I) to earth.

At front contact (a a circuit is made for release relay B and relay C, the circuit of relay C including its coil (1) and contact n1.

' Relay B operates, earthing the incoming a wire at contact 721, opens a point in the remix.

' line and battery. Relay H operates andlocks magnet VM at contact (M2 and connects rotary magnet RM over contacts cs2, m2,dr1, 01, b2, b4 and n2 to earth. The magnet operates and steps the wipers into the bank; only wipers A, B and C however, are in circuit.

If the first line is free test relay H operates in a circuit from earth over contacts 64, m1, coil (I) of relay H, contact 64, wiper C, the cut-off relay of the preselector of the'called up in a circuit over its coil (II), contacts W73, 63, 7L4: and n2. Contact hl closes somewhat later than contact b4 and marks the called line engaged. At contact he also the circuit of magnet RM'is opened and the wipers remain on the first contact. Subsequent operations will be referred to later. p

If the first line is engaged relay H fails to operate. Contact rm makes a circuit for coil (I) of relay C. The relay operates and opens the circuit of magnet RM at contact 01. The magnet armature retracts and opens the circuit of relay C at contact rm. Relay C releases and the magnet circuit is re-madeat contact 01. I r

The wipers are now stepped onto the second contacts. If those be free relay H operates, if not, the interaction of relay C and magnet RM continues.

If all the lines traversed by wipers A, B and C are engaged the wipers are eventually stepped onto the eleventh contacts. Here contact 81 operates but has no function at this stage. However, a circuit is made for relay H over contacts 64, m1, relay coil, contact 64, wiper C, the eleventh contact and coil of relay DR.

Relay H operates opening the rotary magnet circuit at h t and the circuit of coil (I) of relay DR, but this relay is now held over its coil (II).

Relay RN then operates from battery connected to wire RR, over contacts f2, 71.2, 62, wiper A, coil (I) of relay RN, contact 723 to earth. It locks up in a circuit over contacts 4:, M1, M 1 and coil (II) of the relay, and opens the circuit of coil (I) of relay H at contact m1 and that of coil (II) at contact m3 and relay H releases. The circuit of the rotary release magnet RZM is now completed as follows: earth, contacts n2, h-i, b2, 01, (Zrl, 7W2, f6, magnet RZM to battery. The magnet operates and the wipers are restored to the rotary normal position whereupon contact 9W1 is restored. This breaks the holding circuit of relay RN but before this releases, relay E operates in a circuit over back contacts cs3 and 'nml, front contact m1 and contact 64 and locks up over contacts 418.3, 61 and n8. At front contacts 62, 63 and 64 wipers A1, B1 and C1 are connected in place of wipers A,

B and C.

On the release of relay RN the circuit of magnet RZM is opened and the circuit of the rotary magnet RMis closed at contact m2.

The wipers are then stepped into the bank. and search takes place over the second set ofv contacts in the manner beforedescribed.

If all the lines connected in this level are busy the wipers are stepped on to the eleventh contacts and if the group extends to the next succeeding level contact 81 is operated but has no function at this stage. Relay H operates.

over contacts 64, m1, its coil (I), contact 64, wiper C1 and eleventh bank'contact and coil (II) of relay DR. Contact k4 opens the rotary magnet circuit and the circuit of coil (I) of relay DR, but this relay is now held over its coil (II) Relay VS operates in a circuitfrombattery over contacts f2, b2, 62, wiper A1, coil (I) of the relay, contact n3 to earth and at contact 4183 releases relay E. When relay E releases the circuit of coil (I) of relay VS is opened but this relay being slow to release continues to maintain its contacts operated. Relay RN now operates as in the case of unsuccessful search over the first set of contacts and releases relay H at contacts m1 and m3. Relay H releasing,'a holding circuit is closed for relay VS over its coil (II), contacts v81, T722, drl, 01, 62, he and a2 and the rotary release magnet RZM operates in parallel with coil (II) of relay VS. The wipers are restored to their rotary normal position and the holding circuit of relay'R-N is opened at contact 0W1. Relay RN releases disconnecting magnet RZM and completing a circuit for the vertical magnet. The circuit is as follows: battery over magnetVM, front contact os2,back contact 77b2, contacts clrl, 01, b2, b4 and n2 to earth and the wipers are given one vertical step. The holding circuit of relay VS is opened at contact m2 and on that relay releasing and contact 2182 falling back the wipers are stepped on to the first contacts in the level, the rotary magnet operating over back contact 1282 and the circuit previously traced. Search then proceeds in the manner already described over the first set of contacts ofthe new level to which the switch has been raised.

' Assuming that the group has been extended to the first level then when the outlets of all the levels containing lines of the original group have been tested and found engaged, the wipers, A1, B1, C1 reach a limiting position and are stepped to the eleventh contacts of the bank. When the wipers reached the tery on the wire RR. Relay E new releases since its holding circuit is opened at 2183, and

completes an operating circuit for relay RN,

from earth over n3, coil (I) of relay RN, eleventh contact and wiperA, contacts 62, 7L2, f2 to battery on wire RR. At contact rn-l, a holding circuit is closed for its coil (II) and at m4 it opens a short circuit across the coil (11) otrelay F. Relay F now operates in a circuit from earth over contact m3, coil (II), to battery, since contacts up, and 4285 are also open. At contact fl provif sion is made to prevent a short circuit being placed across (3011 (IT) or relay F when the a switch is released and n3) closes, and at f5 a holding circuit for coil .(II) of relay RN is closed depending upon 913. At f6 a circuit is prepared for the release magnet ZM.

On the operation ofRN relay H releases since the circuits for the two coils (I) (H) are opened at m1 and m3 respectively. At he the, circuit for the release magnet ZM- is closed and this magnet operates releasing the switch to normal. .The circuit for ZM is as follows: Earth over contacts 912 and 01.96, hat, b2, 01, (Why-a2, f6, winding of ZM to battery; l

The switch wiper shaft is released to normal and the vertical and rotary off-normal contacts are restored. Relay RN'releases owing to its circuit being opened at m l. At m2 a circuit is completed for the vertical magnetVM as follows: Earth over contact 086, contacts 7L4, 62,01, (Z71, M22, 4282 winding ofvertical magnet VM to battery, and the wipers are stepped up to the first level. At contact rn2also the circuit of relay VS 'is opened and at m3 the circuit of relay Fis opened, these two relays releasing. At 72.92 a circuit for the rotary magnet RM is com pleted and. the wipers are rotated on to the first contact, when, itthis is engaged, search over the level takes place until a free contact is found. If no free contact is encountered and furtherlinesot the group are connected in the next level the wipers are released to rotary normal and stepped upto the next level where the search iscontinued as described above. 7 I

" l/Vhen, during the search over the first or second set of contacts of a level, a tree line is found, relay H operates and locks up and disconnects the rotary magnet as before? mentioned. The speaking 'wir'es are switched through by contacts k2 and 7&3. and contact b1 connects the busying earth to the test wiper in use. Relay DR releases shortly after contact h lchanges over and at contact cZr3 a circuit is made from the ringing generator over the coil (1) of ring tripping relay F, contacts dr3, f3, 72 3, 63, the called line, contacts 62, k2, f2 to battery. The subscribers line is rung, ringing tone being fed to the calling line during ringing from wire RS over contacts (Z74, fat, F203 and 7&5 and is out off when the relay F operates. When the called subscriber replies relay F operatesover the called subscribers loop, and

at f2 and f3 switches the calling subscriber through and completes the circuit for relay D. Relay F locks up'over its coil (11) in parallel with coil (II) of relay H, over contacts b3, bl, n2, the contact fl opening the short circuit across coil (II) of relay F. Belay D operates and reverses the connection of relay A to the incoming speaking wires at contacts (Z1 and d2 to, give the answering supervisory signal.

If all the lines of the group are busy, stepping continues until the eleventh contact in tlie'level in which'the last line of the group of P. B. X. lines is situated is reached. Prior to reaching the eleventh contacts the shaft contacts 81 are operated and relay H operates as'for a tree line. The eleventh contact of this level in the bank of wiper B1 being earthed, relayBC operates over contacts e5, 81, M3, 7 3,713, e3, wiper B1 and eleventh bank contact to earth. Relay RN does not operate as there is no connection over wiper A. Relay VS operates over wiper A1 and although contact cs3 is operated relay E is held by contact 501. Lamp flash current and busy tone are fed alternately from wire BB over contacts 603 and 7L5 to the earthed coil of the answering supervisory relay D. Inthe periods during which lamp fiash current is applied relay 1) operatesand battery over coil (ll of relay A is applied to the a and 6 wires over contacts zm,al1 and contacts amt, Z202 and (Z2 to give the parallel battery flash signal. During thelamp'fiash periods relay B is held in a circuit over back contacts al, 651 2 and d3,

relay A being released during these periods.

A congestion meter may be connected to the eleventh contact of the level in which the lastline of the group appears. In this case relay BC operates to earth connected to the last contact in the level in the bank of wiper B1 and on the operation of contact 501 a circuit is closed over contact 4283 and wiper B for the meter which is connected to the last contact in the level in the bank of wiper l3.

The release of the selector is controlled. by relayA. "When the incoming loop is opened relay A releases followed by relay B. At contact Z11 earth is disconnected from thee wire to release preceding switches. At contacts 63 and 64: points in thecircuits of both coils of relay H are opened.

Relay H definitely releases, disconnects the wiper set in use at contacts 7L2 and b3 and the circuit'of release magnetZM is closed at contact he. The magnet operates and the selector returns to normal, whereupon the opening of contact n2 resultsin the de-energization of the magnet. Contact n3 on opening causes release of relay E if this has been operated. Y

7, During the time magnet. ZM is operated coil (II) of relay A is disconnected from the line to prevent operation if the selector is seized whilst returning to normal If there is a singlelarge group of lines connected to the final selector and occupying all the levels the connections Y may be substituted for those marked X and the switch will in this case commence search in the first level irrespective of the digit dialled.

The operation in this case is as follows:

lVhen the selector is picked up relays A, B and C operate as before. When the first impulse is dialled relay A releases and closes the circuit of the vertical magnet which steps the wipers on to the firstlevel. The vertical off-normalcontacts are operated and on the IB-OPGIiltlOIl of relay A at the end of the impulsea connection is made overthe front of contacts a1 and n1, unoperated rotary rotaryofi-normal contact N72 for coil (II) of I relay DR. Relay DR operates and at conrelay tact (Z72 opens the vertical magnet circuit thereby preventing the remainder of the dialled impulses from taking effect.

A circuit is now closed from earth over contacts 022, h gh? dotted line connection,

contactdrl, coil I) of relay DR to battery and when relay releases this earth is extended over contact 01, dotted line connection, contacts r142, cs2, rotary magnet RM to battery. The rotary magnet operates and I steps the wipers into the bank and towards .fore'and search over successive levels takes place until if no free line is found the'la st line is reached. Contacts n19 are sltuated in this case opposite the last level and are operated when the shaft reaches this level. If all the contacts in this level are busythe wipers are stepped to the last contacts w1th relay E operatedand relay VS operates. Coil (II) of relay DR is energized to guard against deenergization of its coil (I) with operation of H which operates in series with coil (II) of relay DR. Relay E releases and relays-RN and F operate and the shaft is returned tonormal and is re-stepped to level one as previously described and commences a re-search over the outlets of the switch for a free line.

What I claim as new and desire to secure by Letters Patent is: I

' '1. In atelephone system, an automatic switch, a trunk group accessible to said switch comprising two different valued subswitch to the lower valued sub-group'and for continuing the hunting operation .over this sub-group. r v

2. In a telephone system, an automatic switch, a trunk group accessible to said switch comprising two different valued subgroups, said trunk group being assigned a number corresponding to the higher valued sub-group, means responsive to received digit impulses corresponding 'to the number assigned to said trunk group for operating said switch past the'lower valued sub-group to the higher valued sub-group andfor causing it to search for an idle trunk therein, a relay operated when the last trunk in said higher valued subgroup is found busy, means c0ntrolled by said relay for restoring the'switch to its normal position, and means operated when said switch reachesits normal position for operating it to the lower valued subgroup where the hunting operation is con tinued.

3. In a telephone system, an automatic switch having access to groups of trunks over bank contacts arranged in levels, one ofsald groups mcludlng a plurallty of upper levelsand the first or lowest level, means responslve to the operation of said switch by digit impulses to the first of the upper levels of the group for automatically causing the switch to hunt over this level and the succeeding upper levels of the group for an idle trunk, re-

leasing means for the switch, means operated by said switch when it is operated to the last of the upper levels of thegroup for preparing said releasing means, means efiective when said switch has hunted over said level without finding an idle trunk for operating said releasing means to return said switch to normal, and means responsive to said release for operating said switch to the firstlevel and for causing it to hunt over this level for an idle trunk.

4. In a telephone system, an automatic switch having access to trunks over bank con- 1 tacts arranged in levels, means responsive to the operation of said switch by digit impulses switch to hunt over thislevel and levels above until a particular limiting position is reached, said means including means for automatically stepping said switch overa level, for par: tially releasing the switch and operating it to the succeeding level, and for automatically stepping the switch over the succeeding level, means for completely releasing said switch when saidlimiting position is reached, means responsiveto said release for operating said switch to the first level and for continuing the hunting operation over this level, and means responsive to the finding of an idle trunk at any time duringsaid hunting operation for stopping said switch.

- '5. In a telephone system, an automatic switchhaving vertical and rotary movements,

trunks accessiblefto said switch over bank contacts arranged in levels, means responsive to the operation of said switch by digit impulses to alevel other than the first for causing the switch to hunt for an idle trunk in the selected level and in the levels above untila particular limiting position is reached,-means effective when said limiting position is reached for releasing said switch to normal, and means responsive to said release for opcrating said switch to the first level and for causing it to continue its hunting operation over said first level.

6. In a telephone system, an automatic switch having vertical and rotary movements,

a plurality of groups of trunks accessible to said switch-in a plurality of diflerentlevels, one group including one or'niore upper levels and'the first or lowest level, means for operat- 'ing said switch in its vertical movement to "one of'said upper levels, meansfor automatically rotating said switch insearch of an idle trunk, means operated when said switch reaches thelimit ofits rotary movement in a level not the uppermost in the group for releasing said switch in its rotary direction and for operating it to the succeeding level in which the hunting operation is continued, and means operated when said switch reaches the limit of its rotary movement in the uppermost level of the group for releasing saidv switch in both its rotary and vertical directions an'd'for operating it to the first level in which the hunting operation is continued.

7 In a telephone system, an automatic swltch having vertical and rotary movements, trunks accessible to said switch arranged in levels, means for directively operating said switch to one of said levels and for automatically causing said switch to hunt for an 1 idle trunk in said level, means for causing said switch to hunt over succeedinglevels, said means including means for releasing said switch in its rotary direction in case no idle trunk is found in a. particular level and means responsive to said release for operating said switchto the next level and for causing it movement to select a particular level, means.

for automatically rotating said switch over said level to hunt for an idle trunk with one set of wipers,- and means eiiective in case no idle trunk is found for rotating said switch over the same level to hunt for an idle trunk with the other set of wipers.

9. In a telephone. system, an automatic switch having access to groups of trunks in different levels, two sets of wipers, means responsive to the operationof said wipers to a particular level for causing said switch to hunt for an idle trunk in said level with one set of wipers, and means eflective in case all of the trunks accessible to said set of wipers in said level are'busy for automatically causl ing said switch to huntfor an idle trunk in said level with the other set of wipers.

10. In a telephone system, an automatic switch having vertical and rotary movements, two sets of wipers each having access to a plurality of groups of trunks over bank contacts arranged in levels,'means responsive to received digit'impulses for operating said switch in its vertical movement to select one -of saidlevels, means responsive to the termination of said vertical movement for autoanatically causing said switch to rotate over said level and hunt for an idle trunk with one ofsaid sets of wipers, means effective in f case no idle trunkis found for releasing said switch in its rotary movement, and means for automatically causing said switch to ro tate over the same level and hunt for an idle trunk with the other set of wipers.

11. In a telephone system, an automatic switch having two sets of wipers, a plurality of trunks accessible to-each set ofwipers in 1 each of a plurality of different levels, means responsive to the operation of said wipers to a particularlevel for causing said switch to hunt foran idle trunk in said level with one set of wipers, means effective in caseall of the. trunks in said level accessible to said wipers are busy for causing said switch to hunt for an idle trunk in said level withthe other set of wipers, and means efiective in case all of the trunksin said level accessible to said second set of wipers are also busy for automatically raising said wipers to the succeeding level and continuing the hunting operation in said succeeding level.

. .12.,. In,a telephone system, an automatic switch having two sets of wipers, a plurality of trunks accessible to each set of wipers in each. of a plurality of different levels, means responsive to the operation of said wipers to one of said levels for causing said switch to hunt for an idle trunk in said level with one set of wipers, means effective when the switch reaches a limiting position for causing said switch to hunt for an idle trunk in the same level with the other set of wipers, and means effective in case said switch again reaches said limiting position for raising said wipers to the succeeding: level and continuing the hunting operation in said succeeding level.

13. In a telephone system, an automatic switch having two sets of wipers, arplurality of trunks accessible to each set of wipers in each of a plurality of difiierent levels, means responsive to the operation of said switch to one of said levels for causing it to hunt for an idle trunk in said level with one set of wipers, two relays operated when said wipers reach a limiting position in said level, means controlled by the first relay for returning said wipersto the beginning of the level and for again initiating the hunting movement, and means controlled by the second relay for transferring from the first to the second set of wipers so that the succeeding hunting operation takes place with the second set of wipers.

14:. In a telephone system, an automatic switch having vertical and rotary movements, two sets of wipers, a plurality of trunks accessible to each set of wipers in each of a plurality of difierent levels, means for directively operating said switch in its vertical movement to one of said levels, means for automatically rotating said switch in said level to hunt for an idle trunk with one set of wipers, means for automatically rotating said switch in the same level to hunt for an idle trunk with the other set of wipers, means operated when said switch reaches the limit of its rotary movement for releasing it in its rotary direction, and means responsive to said release for initiating the second huntlng movement in case only the first hunting operation has been completed and for operating said switch to the succeeding level in case both of said hunting operations have been completed.

In testimony whereof I afiix my signature.

JAMES ERRIGAL TEES.

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