US1639858A

US1639858A - Plug

Info

Publication number: US1639858A
Application number: US719465A
Authority: US
Inventors: Earl F Potter
Original assignee: Kellogg Switchboard and Supply Co
Current assignee: Kellogg Switchboard and Supply Co
Priority date: 1924-06-12
Filing date: 1924-06-12
Publication date: 1927-08-23
Anticipated expiration: 1944-08-23

Description

Patented Aug. 23, 1927.

vu,tartan surrey-Armi* oFFics..

vEARL F. P OTTEILOF GLENCOE, ILLINOIS, ASSIGNOR TO KELLOGG SWITGHBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

PLUG.

Application led June 1,2, 1924.` Steral No. 719,465.

My invention lrelates to improvements in connecting plugs, and has to do more particularly with that class of plugs which are adapted to have connected thereto one or more instrumentalities. The plug of my invention is particularly adapted for use in cennection with radio or wireless receiving sets to which may be connected a number of head phones or a loud speaker through the medium of the plug, and the jacks of the receiving set; and an object of my invention is to construct a connecting plug of a few and simple parts, so arranged as t-o be easily assembled and at the same time very duil' rable.

The plug` of my invention is of the series type and is provided with means toi' per mitting the connection of more than one instrumentality at the same time. The plug is provided with spring terminal meansv which obviates the necessity of screw terminals. The cord tips of the instiuinentaliti-es desired to be connected to my plug, are inserted under the spring terminals and the tension ot' the spring terminalsis such as to hold the cord tips in engagement therewith againstl displacement;

A feature of the plug of my invention is the provision of an auxiliary tip contact element in association with certain of the spring terminals of my plug so thatV a loud speaker may be connected to my plug and in circuit with said auxiliary tip element exclusive of a headphone set which may be connected in circuit with the tip conductor and tip contact of my plug. The tip contact of my plug is adapted to make contact with :Ai-ving set so that'the auxiliary tip thel tip contact spring of the jack of the radio ug may be inserted intotlie jack of I contact and sleeve contact of said plug make contactual engagement with the tip and sleeve contact springs respectively of the said Jack so that the said other instrumentality will be connected in circuit with said radio or kwireless receiving set and they headphone set will be in open circuit.

The above features, as well as others, will be more specilically pointed out in the ensuing specilication and appended claims, and for a more complete and clearer understanding of my invention reference may be had to the accompanying drawings in which like reference characters in the several views denote similar parts.

Referring to the drawings:

Figl is a view of my connecting plug lassembled Fig. 2 is a view of the connecting plug with the handle or sleeve in section to clearly illustrate the plug and also showing the tip and sleeve contacts of the plug in engagement with the tip and sleeve contact springs respectively of a suitable tivo conductor ack for receivin said plug;

Fig. 3 is a view simiar to Fig. 2 and illustrates another view of the plug and also shows the auxiliary tip contact and the sleeve contact ofthe plug in contactual engagement -with the tip and sleeve contact springs of a suitable two conductor spring jack;

Fige is another view of the plug of my invention similar. to Fig. 3 but taken from a different angle;

Fig. 5 is an enlarged sectional view taken on the line 4 4 of Fig. 2;

Fig. 6 is an enlarged end view of the plug` of my invention; 'i c y Fig. 7 "s a disassembled perspective view of the spring terminals and insulating block ot my invention, and

Fig. 8 illustrates diagrammatically the vplug of my invention and the circuit connectons for operatively connecting either a head set unit or a loud speaker unit.

Referring now 1n detail to my inventionv as illustrated in the accompanying drawings, 'the plug comprises a shallow cup slr nl member 2 internally threaded and a idrical ienducting sleeve il t'vliith is provided with a central opening for receiving the insulating sleeve 4. The sleeve 3 is provided with a reduced end portion 5 which provides an annular shoulder G. A central orifice 7 is `provided inthe cup member 2 and is of a size to receive the end por4 tion 5 of the member 3 and its annular shoulder '6 rests against ythe faceA of the cup member 2 when in -position in said orilice 7. An anuxiliary tip conductor member 50 of suitable conducting material and cylindrical in shape is provided and is of a size to pemit its insertion into the central opening in the insulating sleeve 4,

' the said 'member 50 having a circumferential iiange 51 `formed integrally with one of its tends for purposes to be pointed out later, the other end of said member being threaded rto receive the auxiliary tip Contact member 52, said Contact member 52 being separated and insulated from the sleeve contact member 3 bythe insulating washer 53. A cylindrical non-conducting member 54 is provvided which is adapted to tit into vthe auxiliary Acylindrical tip conductor 50. A conducting ystem or bolt 9 extends through v'the insulating member 54, its one end 10 being threaded, and its forward `end being pro vided with an integrally formed and spherically shaped tip contact member 11 which is 4insulated from the auxiliary tip contact 52 by means oit the. insulating` bushing 12, the insulating sleevefmeinber Z54 insulating said bolt 9 from the auxiliary tip conducting -member 50. A spring terminal 13, angular in shape is provided and has a. disk portion 14, in which disk portion 14 is a central orifice 15 of a size to receive the protruding end '01 the insulating sleeve 4 so that the disk portion 14 will engage the inner face of the cup member 2 and also vengage the end oit the sleeve member 3.

rlhe disk portion 14 'is also provided with a pair ot diametrically opposite orifices 16 which are adapted to receive the non-conducting studs 17. The sleeve 4 insulates the Aterminal 13 from 'the auxiliary tip conducting member 50. The terminaly 13 serves as a terminal for the sleeve conducting member 3 of my plug. A spring ter minal 19, having 'a disk portion V2O, is provided7 the disk portion 2() being Aprovided with a central orifice 21 of a size to iit over the auxiliary tip conducting member l50 so that the said disk portion 2O will have convftactual engagement with the said member 50 and also with the `flange 51 vformed with V"said member 50. The disk portion 2() iis also provided with a pair of diametrically "opposite oriiices 21l to receive the studs 17.

An"insulatingplate or bushing 22 provided with 'a central oriiiceof a size to receivethe 'protruding end of the insulating sleeve member 4 and a pair o't dialnet 1ically oppoas a terminal for the auxiliary tip conducting member 50.

A terminal 23, angularv in shape and lprovided Iwith a disc portion. 24.; is vprovided and has a central orilice 25 of a size to receive the conducting bolt 9, and a pair of dian'ietrially opposite orifices 26 provided in said disk portion 24 are adapted to receive thev studs 17. An insulating plate or bushing 27, provided with a central opening of a size to-receive the conducting'V 'bolt 9 and a pair 'of diametrically opposite oriiices 'of a size to receive the Vstuds 17, rests between the disk portion 20, of the terminal 19 and the disk portion 24 of the terminal 23 to insulate one from the other. A 'suitable pocket or cut-out portion 28 is provided in the bushing 27 and is of .a size to receive thev flange 51 oli'the 'auxiliary tip conducting member the said bushing 27 also iiisulating the said member 50 from the conducting bolt 9 and also from the disk portion of the terminal 23. The threaded end 10 oi' the conducting bolt 9 protrudes through the aligned

central orilices

15, 21 and 25 of the disk portions 14, 20 and 24 the

terminals

13, 19 andv respectively, and also *extendsy through `the Vcentral openings inthe insulatii'ig bushings 22 and l27 and a Vslotted nut 29 having' screw-tlneaded engagement with the threaded end v10 of the conducting' bolt 9 is screwedl down against the tace of the disk portion 24 of the terminal 23 and clamps the

terminals

13, 19 and 23 and insulating bushings 22 and 27 in position and at the same time forms a conducting means ybetween the tip Contact 11 o1 the conducting bolt 9 and its terminal 23. When the nut 29 is screwed down on the-threaded end 10 of the conducting bolt 9 the tip contact 11 ot saidv bolt 9 will hold the auxiliary tip contact 52 and its conducting lmember 50 in position against movement. The 'studs 17, which before described are oi suitable insulating material, extend through 'the aligned dianie'trically opposite vorifices 2 of the cup member 2 and the

orifices

16, 21 and 26 of the`terminals'13, 19 and 23 and the insulating bushings 22 and 27 to hold the said `terminals' vand bushings in position against rotary movement relative to each other. The terminal 13 is provided with a rearwardly extending `biturcatcd spring member which bifurcations form a pair of spring members E13l and 1o2 'formed vto bend inwardly; and 'the terminal 19`is provided with a rearwardly extending spring` member 19 formed to bend inwardly. rlhe terminal 23 is also'provided withV a rearwardly extending Yspring-member 23,.formed 'to bend inwardly.

An insulating block 31V is provided and has a central orifice 32 ot a size to receive the end/10 ot the conductingy bolt9.A An annular recess 33 concentric with the orilice 32 is provided, into which thenut .29,A whichV clamps the terminal members "13, r19'vand 23 and bushings 22and 27 together, extends to permit the block 31 to rest against the tace of the disk 24 vof the terminal 23.' The face 34 ot the block 31, which rests Eagainst the disk 4 ofthe terminal 2:3-sprovided vith a pair of diametrieaily, oppositeVoriices 35, into which'the end of theistuds 17 extend to prevent turning otv the block 31 v-onthe' conducting bolt 9. The block 31 is secured on the conducting holt 9 by means of a slotted nut 36 which has screw-threaded engagementwith 'thethreaded end 10 ot vsaid bolt 9, the said nut 36 resting in a suitable annular recess 37 in the rear tace oi.' the block 31. The block 31 is provided with flat faces 3S and39,-the said face 39 adapted to be engaged byA the tree ends of the spring members 19 n and :23 of lthe terminals 19 and 23 respectively, and the said tace 38 adapted to he engaged'bythe tree ends ot the spring members 13 and 132 oit' the terminal 13. vWhen theblock 31 is inserted between the spring members 19 and 23 of the terminals 19 and 23 and the spring member-S13V andV 132 ot' terminal 13, i

the block 31 will iioicesaid spring members outward against their normal spring tension. The taces 33 andv 39 of the yblock 31 are providtnl respectively with groovesv40 with the spring members 13i-and 132 of the terminal 13. A torni ot cord. tip that may be used isl illustrated at 42 in ig. 2.

Assuming that a headphone set and Va loud vspeaker are to be connected to my plug the cord having the headphone set connected thereto will be provided with a pair of cord tips such as (F ig. 2), and .the cord having the loud speakerconnectedthereto will also have `a pairI of cord tips 42 connected thereto.

New to connect the kloud speaker toniy plug one oi" the cord tips 42 connected to the cord ot theloud speakerA is forced into the groove, 40 beneath the` spring member 13 otv the terminal 13 whereby the y loud speaker is connectedvto the sleeve conductor 3 of my plug, and the other cord tip 42 is forced into the Oroove 41 beneath the spring member 19 of the terminal 19 whereby the 'loud Vspeaker isr connected tothe auxiliary tipconducting .member 50, Vvand the ysaid "J with its tip conductor 11 engaging trie ycordl tips 42 are held in the grooves by the spring tension of the `said spring members l13" and 19 of

terminals

13 and 19 respectively.V One of the cord tips oit the cord` 'connected to the headphone set is 'now forced intoy the'other groove 40 beneath the spring member 132 ot the terminal 13which will connect the headphone set tothe sleeve conductor 3 ot my plug,`and the other cord vtip'of said cord will be forced intofthe groove 41 beneath the spring member 23V ot the terminal A3 which will connect the headphone set to the tip conducting rod 9 of my plug. The tension ot the spring members 132 and 23 will hold the cord tips 427m the grooves 40 and 41 respectively, and insurepositive connection between said cord tips andsaid` terminals. Thus it will be `seen that the headphone set and the loud speakerare both connected to the sleeve conduct-.or 3 of my plug and that the headphone is connected to the tip conductor 9 while the loud speaker is connected to the auxiliary tip conductor 50. This connection` Varrangement may, however, 'be reversed by

sleeve conductors

46 and 47 of a jack .l

,which is connected to the output end ot a receivingr circuit. T he plug P when` connected as illustrated in F ig. 2 to the jack l lip conductor 46 of the jack and its sleeve conductor v3 engaging the sleeve conductor 47 oit the jack connects the loud speaker unit LS in circuit with the output endet. the receiving circuit. rllhe plug when connectedas illust-rated `in Fig. 3 to the jack vJ with its auxiliary tip conductor 52 ven- 0raging the tip rconductor 46 ot the jack and its sleeve conductor 3 engaging the sleeve conductor 47 ot the jack, now connects the head set unit Rin circuit with the output end ofthe receiving. circuit. i t

I provide afproteetive sleeve or handle 44 of suitable insulating material, one endV of which is threaded and has screw-threaded engagement with the cup member 2 of the plug. This handle or sleeve serves as a cover or enclosing member for the plug vand also as aliandle for grasping the plug, The handle 44 is also provided .with a pair ,otorilices for the stay cords ot the head is providedwith a stay cord which is insertl f ed through one of the orifices 45 in the handle 44 and tied so as to allow slack in the individual conductors leading toV the cord tips se that the cord tips will not be accidently withdrawn from undei' the spring members oit their respective terminals In Fig. 2 I show the tip contact spring 46 and slee-ve ycontact spring 47 of a well known two conductor spring jack which is suitably and operatively associated with the radio or wireless receiving set. To connect the headphone set in circuit with the radio or wireless receiving set my plug will be inserted into the spring jack to such an extent that the tip Contact spring 46 of the said spring jack registers and makes contact with the tip contact l1 of the plug, and the sleeve contact spring 47 registers and makes contact with the sleeve contact member 3 of said plug as is shown in Fig. 2 of the drawings. The plug will be held iii this position by the spring tension of the contact springs 46 and 47. The loud speaker will, when the plug is in the position illustrated in Fig. 2, be in open circuit since the auxiliary tip contact and the sleeve contact spring 47 will still remain in contactual engagement with the sleeve contact member 3 of the plug but at a different point thereon. `A circumferential groove 52 is provided in the auxiliary tip contact member 52 to etl'ect a snap action of the plug when the said plug is inserted into the spring jack as illustrated in Fig. 3, and the contact springs 46 and 47 will hold the said plug in this position due to the tension 'of said contact springs. The head phone set will now be in open circuity since the tip contact member l1 of the plug will not engage the tip contact spring 46 and as'the said member 1l is in no way conductively connected with the auxiliary tip contact member 52 no circuit is closed for the head phone set.

From the foregoing it will be seen that either the loud speaker or the head phone set may be connected to the radio or wireless receiving set by adjusting the plug in the spring jack having the contact springs 46 and 47, and that it is impossible to connect both the head phone set and loud speaker to the radio or wireless set at the same time. The advantagesv ot this arrangement,

tated'and necessity `for switches to cut from one instrument to the other obviated.

While I have described and illustrated a particular embodiment ofmy invention it is to be understood that I do not wish to be limited to the exactlstructure as shown and described, :as changes and modiiications will readily suggest themselves, therefore, I intend to cover all that which may come within the scope and spirit or the appended claims. l

- vWhat I claim as new and desire to secure by United States Letters Patent, is:

l. In a connecting plug of the character described comprising a hollow' sleeve conductor member, a cup member for supporting said hollow sleeve member, a tip conductor member and an auxiliary tip conductor member extending through said hollow sleeve member but'insulated therefrom, said tip and said auxiliary tipl conductor members also insulated from each other, ai spring terminal for each of said conductor members and insulated from each other, a block of insulation for separating said spring terminals and provided with grooves for receiving andconnecting terminal members leadingfrom diii'erent instrumentalities with said spring terminals, said tip conductor member and said auxiliary tip conductor member arranged so that a circuit may extend'through said connecting plug to oiieof said instrumentalities via said tipconductor member and said sleeve concluetor member or to the other of said instrumentalities via said auxiliary tip conductor member and said sleeve conductor member.

2. Inka connecting plug of the character ber secured to one end of said `cylindrical 1 4conductor member, said conducting bolt exd tension extending Athrough said cylindrical conductor member so that said tip conductor member is brought into close proximity to said auxiliary tip conductor member, mea-ns for insulating saidv conductor members from each other, a spring terminal for each of said conductor members and insulated from each other, means for engaging said bolt extension for clamping said conductor members and said spring terminals in their assembled position, a non-conducting block for separating said spring lterminals and -for connecting conducting members leading from different instrumentali- -ties to said spring terminals, the connection with the spring terminal of said sleeve conductor member being common to the connecminal 23 is also provided with a rearwardly extending Vspring member 23 formed to bend inwardly. n

An insulating block 31v is provided and has a central orifice 32 of a size to receive the end of the conducting bolt 9. kAn annular recess 33 concentric ivith theoriiice 32 is provided, into which the nut 29, which clamps theterminal

members

13, 19 and 23 and bushings 22 and T together, extends to permit the block 31 to rest against the face of the disk 24 of theterminal 23. The face 34 of the block 31, which rests against the dis* 240i the terminal 23 is provided Ywith a pair of `diametrically opposite ori- .lices 35, into Which, the end of the studs 17 'extend to prevent turning' of the block 31 on the conducting bolt 9. The block 31 is secured on the conducting bolt 9 by means ofva slotted nut 36 Which has screw-threaded vengagement with the threaded end 10 vof said bolt 9, thev said nut 36 resting in a Ysuitable annular 'recessr37 'in the rear face of the block 31. The block 31 is provided 1with flat faces 38 and 3,9, the said face 39 adapted tok ce engaged by the free ends of the spring members .19 and t23 of the terminals 19 and. 23 respectively, and the said face 33 adapted to be engaged by the free ends of the spring members 13 and 132 of the terminal13. l 1When the blockr31 is inserted betveen theI spring members 19 and 23 of the terminals 19 and-23 and the Which-is connected to the output end of a spring members 13 and 132 of terminal 13, the block 31 will force-said spring members outward against. their normal spring .ten-V slon. The faces 33 and 39 ofthe block 31 are provided respectively. With grooves 4()v and ,41. there being two'grooves -40l in the face 33m alignn'ient with the spring members 19 and of the terminals 19Y and 23, and groovcs40 of ivhich there aieftivo in the face 3910i2 the block 31A are in alignment with tliespring members 13 and 132 of the terminal 13. A form ofv cord tip that may be usen is illustrated `at 42 in Fig. 2.

Assuming that a headphone set and a loud speaker are to be connected to my plug the cord having the headphone set vconnected thereto will be provided With a pair of cord tips such as (Fig. 2).,and the cord having the loud speaker connected theretowvill also have a pair of cord tips 42.connected thereto. y s

Now to connect the Aloud speaker to my glug one of the lcord tips 42 connected to the cord of the loud speaker is forced into the groove 40 beneath the spring member 13. of the terminal 13 whereby they loud speaker is connected to the lsleeve conductor 3 of my-plug, and the other cord tip 42'is forced into the groovev 41 beneath the spring member 19 ofthe terminal 1,19 whereby the loudL speaker is connected to the auxiliary Vtip conducting member 5 0, Yand the ksaid 'A speaker the terminal 23 which Will connect the headphone set to the tip conducting rod 9 of my plug.y The tension of the spring members 132 and 23 Will holdthe cord tips 42 in the grooves 40 and 41 respectively, and insure positive connection between said cord tips and said terminals. l seen that the headphone set and the loud are bot-h connected to the sleeve conductor 3 ofmy plug and that the headphone is connected to the tip conductor 9 While the loud speaker is connected to the auxiliary tip conductor ,50. This connectiony varrangement may, however, be reversed by yreversing the connection of the cord tips 42. of they headphone set and loud speaker relative to the spring members 19 and 23 of the terminals 19 and 23 respectively.

Referring now to Fig. 3 I illustrate the plug tip, auxiliary tip, and

sleeve conductors

11, 52 and 3 associated with the tip and sleeve conductors 46 and 47y of a AjackJ receiving circuit. The plug P when connected as illustrated in Fig. 2 toY the `iack J vvi'tli `its tip conductor 11 engaging the tip conductor 46 of the jack and its sleeve conductor 3 engaging the sleeve conductor 47 of the jack connects the loud speaker unit LS in circuit with the output end of the receiving circuit. The plug when connected as' illustrated in Fig. 3 to the jack @l .vithv its auxiliary tip conductor 52 engaging thetip conductor ofthe jack and its sleeve conductor engagingr the sleeve conductor 47 of the jack noiv connects the head set unit R in circuit with the output end of the receiving circuit.

I provide a protective sleeve or handle 44 of suitableA insulating material, one end ef Thus it Will be` which is threaded and has screw-threaded engagement With the cup member v2 of the plug. This handle or` sleeve serves as cover or enclosing member for the plug and ,also as a handle for grasping the plug.

The handle 44 is also provided With a pair of orilices 45 for the stay cores of the head phone set and loud speaker' cords for pure poses as Will nov7 be described.

To relieve the strain from the connecting cords, should the plug be accidently Withdrawn by grasping the cords instead of the handle 440i the plug, each connecting cord is provided lvvitli a stay cord Which is inserted through one of the orifices 45 in the l and operatively associated 'with the radio or wireless receiving set. To connect the headphone set in circuit with the radio or wireless receiving set my plug will be inserted into the spring jack to such an extent that the tip cont-act spring 46 of the said spring jack registers and makes contactr with the tip contact l1 of the plug, and the sleeve contact spring 47 registers and makes contact with the sleeve contact member 3 of said plug as is shown in Fig. 2 of the drawings. .The plug will be held in this position by the spring tension of the contact springs 46 and 47. The loud speaker will, when the plug is in the position illustrated in Fig. 2, be in open circuit since the auxiliary tip contact` member 52 is free from 'contactual engagement and also free from conductive association with the said contact springs 46 and 47. Now should it be desired to connect the loud speaker in circuit with the radio or wireless receiving set and the head phone set disasseciated therefrom, the same may be accomplished by inserting the plug into the spring jack to its full extent thereby causing the tip contact spring 46 to register and make contact with the auxiliary tip contact 52, and the sleeve contact spring 47 will still remain in contactual engagement with theV sleeve contact member 3 of the plug but at a different point thereon. 4 A. circumferential groove 52 is provided in the auxiliary tip contact member 52 to ei'l'ect a snap action of the plug when the said plug is inserted into the 'spring jack as illustrated inFig. 3, and the contact springs 46 and 47 will hold the said plug in this position due to the tension of said 'contact springs. The head phone set will now be in open circuit since the tip contact member ll of the plug will not engage the tip contact spring 46 and as the said member ll is in no way conductively connected with the auxiliary tip contact member 52 no circuit is closed for the head phone set. y

From the foregoing it will be.- seen that either the loud speakeror the head phone set may be connected to the radio or wireless receiving set by adjusting the plug in the spring jack having the 'contact springs 46 and 47, and that it is impossible to connect both the head phone set and loud speaker to the radio or wireless set at the same time. The advantages of this arrangement, of course, are at once obvious and apparent. The handling of the set is greatly facilitated and necessity for 'switches to cut from Vone instrument to "the other obviated described comprising a hollow sleeve conductor member, a cup member for supporting said hollow sleeve member, a tip conductor member and an auxiliary tip conductor member ext-ending through said hollow sleeve member but insulated therefrom, said tip and said auxiliary tip conductor A'members also insulated vfrom each other, a

spring termina-l for eac-hof, said conductor members and insulated from each other, a

block of insulation for separatingV said spring terminals and provided with grooves for receiving 'and connecting terminal meinbers leading from different instrumentali- 'ties with said spring terminals, said tip condi'ictor member and said vauxiliary tip conductor member arranged Vvso that a circuit may extend through said kconnecting plug to one of said instrumentalities via'said tip conductor member and. said sleeve conduc-A VVtor member or to the 4other of said instru-` mentalities via said auxiliary tip conductor member and said sleeve conductor member.

2. In a connecting plug of the lcharacter described including 'a hollow sleeve conductor member, va cup shaped member lfor receiving and supporting said sleeve conducting member, a tip conductor member having a conducting bolt extension, a cylindrical conductor member extending through said 'sleeve conductor member but insulated therefrom, anv auxiliary tip conductor meniber secured 'to one end of said cylindrical conductor member, said vconducting bolt extension l extending Vthrough said cylindrical conductor member 'so that said tip conductor member is brought into close proximity to said auxiliary tip 'conductor member, means for insulating said conductor members from each other, .a spring terminal for each of said conductor members and insulated from each other, means for engaging said bolt extension for clamping said conductor members and said spring terminals in their assembled position, a non-conducting block for separating `said spring terminals and for connecting conducting members leading'from differentinstrumentalitiesto said spring terminals, the connection with the spring terminal of said sleeve conductor member being common to the conneclil() tions with the spring terminals of said tip f connecting plug to one of saidv instrumenfkr talities via said sleeve V conductor 'member and-said tip conductor member or to the ducting bolt extension extending through said cylindrical conductor member so that said tip conductor member is'brought into close proximity to said auxiliary tip conductor member, means for insulating said conductor members from each other, a springterminal for each of said conductor members and insulated from each other, means for engaging said bolt extension for clamping said conductor members and said spring terminals in their assembled position, a nonconducting bloclr for separating said spring terminals and for connecting conducting members leadingk from different instrumentalities to said spring terminals, a spring terminal jack having contact springs, said tip conductor member and said auxiliary tip conductor member being sol arranged that a circuit may be closed through said connectsl ing plug via said Contact springs and said tip and sleeve conductor members, or via said Contact springs and said auxiliary tip and sleeve conductor members.

4. A connecting plug in combination with a spring jack, a sleeve conductor member for said plug, a tip conductor member having an extension integrally formed therewith and extending through said sleeve member, a cylindrical conductor member interposed between said tip conductor extension and said sleeve conductor member, an auxiliary tip conductor member secured to said cylindrical conductor member, means for insulating said sleeve, tip and auxiliary conductor elements from each other, a spring terminal for each of said conductor elements insulated yfrom Veach other, a block of insulation secured to the extension of said tip conductor member and adapted to separate said spring terminals and to secure terminals of diiferent instrumentalities to said spring terminals, a pair of Contact springs adapted to be engaged by said plug so that a circuit may be established through said plug for one of the instrumentalities via said tip and. sleeve conductor Vmembers -exelusive or" said auxiliaryV tip conductor niembei, or adapted tobe engaged by said plug so Y that a circuit may be established iior the.v

other of said instrumentalities via .said aux:`v iliary tip 'conductor member land said sleeve conductor member exclusive or said ductor-member. i

5. A connecting plug in combination wit a spring jack, a sleeve conductor member for said plug, a tip conductor member having an extension integrally formed therewith and extending through said sleeve member, a cylindrical conductor member interposed between said tip conductor exten sion and said sleeve conductor member, an auxiliary conductor member secured to'said cylindrical conductor member, means for insulating said sleeve, tip and auxiliary conductor elements from each other, a spring terminal for each of said conductor elements insulated from each other, a block of insulation secured to the extension of said tip conductor member and adapted to sepai'ate said spring terminals and to secure terminals of different instrumentalities to said spring terminals, a. pair oi contact springs, said plug adapted to engage said contact springs in one position to close a circuit through said plug and one oi' ysaid instrumentalities while said other instrumentality is in open circuit, and adapted to engage said Contact springs in another position, to close a circuit through said plug and said other instrumentality while said one instrumentality is in open circuit.

6. The Combination of a two conductor spring jack and a three conductor plug, a pair of instruments connected to said plug, said plug and jack cooperating to permit either of said instruments to be operatively associated with said two conductor jack independent of the other, two of the contacts of. said plug having grooves therein for cooperation with one of the springs of said spring ack to maintain said plug in either of its operative positions.

7 The combination of a two conductor spring jack and a three Contact plug, a pair of instruments connected to said plug so that one conductor ot' each instrument is common toy one conductor of said plug, said plug` and jack cooperating to permit either of said instruments to be operatively associated with the springs of said two conductor jack independent ot the other depending upon the position oi said plug relative to said jack, two of the contacts of said plug having grooves therein for cooperation with one of the springs or" said spring jack to maintain said plug in either of its operative positions. f

8. The combination oi" a two conductor spring jack and a three contact removable plug for operating therewith, a pair of intip construments having a common connection to one Contact of said plug und; separate connections to the other contacts of. sa-icl plug, said plug Cooperating with said jack sothat either of said instruments may be operativeremain inl either.v of its operative positions to effect said connection between theV springs 10 of said jack and the instruments connectecb to said plugs.

Signed byline at Chicago, County of Cook, State of Illinois, this 10th. day of June, 19%.

EARL F. POTTER.