US2663850A - Key plug for spectator announcement systems for public events - Google Patents

Description

Dec. 22, 1953 E. R. MELLINGER Erm. 2,663,850

KEY PLUG FUR SPECTATOR ANNOUNCEMENT SYSTEMS FOR PUBLIC EVENTS Original Filed Dec. 2l 1948 4 Sheets-Sheet l BYE' ,2. am

De. 22, 1953 E. R. MELLINGER ETAL 2,663,850

KEY PLUG FOR SPECTATOR ANNOUNCEMENT SYSTEMS FOR PUBLIC EVENTS Original Filed Dec. 2l 1948 4 Sheets-Sheet 2 www AL 2,663,850 R ANNOUNCEMENT SYSTEMS FOR PUBL Orlglnal Flled Dec. 2l, 1948 4 Sheets-Sheet 3 Dec. 22, 1953 E. R. MELLINGER ET KEY PLUG FOR SPECTATO IC EVENTS zow/mm Mm y 5 7 s J www m wf l.; In i BY ma. *A

Dec. 22, 1953 E. R. MELLINGER HAL v 2,663,850

KEY PLUG FOR SPECTATOR ANNOUNCEMENT SYSTEMS FOR PUBLIC EVENTS Original Filed Dec. 2l 1948 4 Sheets-Sheet 4 Ylllllllzlllfllzllllllz. f/

Patented Dec. 22, 1953 UTN-[TEl);A ES GFFIiICE KEYirLUG. FOR sPEcTA'ron Armonium-- MENTfsYsTEMs- Fon PUBLIC EVE-Nrs-T Efdward-'f R." Mellinger: andT-Ruthi E; Mellingen Williamsport, Paiand Dudley.;-v B.-Howard,-`

Chatham,f-N. J i

,said Howard-fassignor to said` Edward R. Mellinger and Ruth E. Mlliger Original application--December- 21,1 1948;*- Serial-f No. 665412. Divided'r and thisziapplication June? 11, 1952, Serial-No.5294,594-

(CL. 339f-45) Claims.

l. The invention relates in general .to-local elec-l trical voice communication systemsoi whiclr an example is -the= public address system, ands hasparticular referenceto a specially designed .comemunications system adapted to the local reporting-r Byis meant individual athletic games` of v.public events Afor the benefit of spectators.- public events which mayor maynot beincluded in'a scheduled series, racing programs. and aircraft demonstrations Awhich mayembracea number ofconsecutive sub-events, horse shows and other animalshows.

political conventions, andthe like.:

This :application is a divisional of our-.co-pending4A application, Serial.,=Nu1nber 66,412; filed De'- cember 21, 1948, for improvementsinflSpectator Announcement "System for: Public L Events, now abandoned..

Prior. to our: invention, running. accounts of.`

public events have been made/available exclusively .to persons; in their'homes andatfother places remote .from thescene ofthe events through the medium of. radio or. television broadcasting. WithL the exception of brief, infrequent loudspeakerr an-Y nouncements .oi incidents of specialinterestsuch as the names of principal participants-andisub'-- stitutions therefor as ,-theyfaremade, the spectators at. 'public events havehad 'to 'depend-upon.

their own direct observation to follow the pro-l gress of the action.

There are others, however, who attendfsportsl events less frequently and are -not--so closely -attuned to the contest in progress.- Persons -in-this category, particularly those-Who have1defe'cti'v'el vision or have lost some -of their youthful-alerteV ness, miss a great deal of the action and heretofore have had to rely upon theiry better informedneighbors at the gaine `to `keep-them posted. Al`

though they .enjoythezatmosphere ofsth'esgam'e and those parts. of the action Whichtheypare 'ablet to comprehend,- they really need toi haver-their powers of visual perception supplemented by 1announcement service somewhat like-that which is;y at the disposal of the -radio ,and-television audiA14 ences.r However, itis iinpracticableto use radiosets or loud speakers at the sceneof a sportsl event to broadcast a running account of the action. for the benet4 of a minority of the spectators..

principallytbecause of the great.. annoyance .to others present who do not need such service..

Inthe -caseofcer-tain- Iother -publicevents,V suoli.

asfhorse shows and other animal shows .and ai1-.

craft demonstrations,- the-entire assemblage of spectators would-benefit byav running.. accountI of-the-sub-events that-make up the whole. In? these,- events,- greater importance is attach edtothe-individualfentrants onperiormers and there usually is not-thecontinuityoi action athletic1 game..-. Consequently, vit.y oftentimes.. is

very..-diiicult to'- keep. in vclose-toucl'i with all de-V tails ,of .the-action `by-visual Vobservation from axed position in the stands. This handicap. is, in

this --instance;- more detrimental to -thehab'itues andto-,thosewho may-have a-personal---interest in certain l particular entrants than 'to the casualiv Heretofor-e,7 in--this, class of. public. events'-greater-use-has been made kof-the public address system-as ameans-oir supplementing the` direct observation -of-A spectator-shy .-reports-from` spectator.

announcers more advantageously located; -v However, any1-such service-has had-to beg-restricted toA the-announcement ofentrants and-the results ofindividualcontests, for Aotherwise-there would be anobjectionable continuous blare ofloudspeakers.4 W-th-the-above situation in mind, it has-beenour primary object to'serve the needs of spectators :at public events by .-providing--a-local communications :system which includes individual telephone receivers suitably located-for-.convenient use-by thosev spectators who desire the service, to-

gether .withl means whereby- Aa.- specialv announcer-- may transmit for their benet -an account of-thefaction, which-necessarily will bea version-'of the usual-17 radio and television broadcastA 'modied Yto suit.y the Vneeds, vof 1 listeners who' are in directobservation. Obviously, thecustomary-broadcast contains animated, crescendo utterances intended.

to.; convey :the-spirit-of the event= tothe distant audience; 'and also f mentionl of` details whichl any? spectator can see with his fown eyes fand-fully comprehend. In" accordance with our invention;

the .special 'announcer .occupies/a i-contrfoll booth located in ai position-"Winchl affords a clear'viewf ofetheactionfand has-at his disposalmeans for' listening i in 'on'f-the radio' and television br'oad cast, together with additional means bywhiclifhema-y 'switchthe latter into the localV announcement system Whenever the announcements bein'g'i broadcast happen to be appropriate forve'rbat'iin consumption by spectators.

Another object'of the invention isjto provide an announcement system" for Vspectators'y whichv` embodsmeans'for restricting use of the'indivdual telephone vreceivers to tnose' spectators wrm 5 have paid a toll charge.' In'this' feature, 'we'ha've accesso departed from the usual employment of coincontrolled apparatus, because of its inherent defects which we have sought to avoid. Instead, we have provided seat-installed jackboxes in electrical connection with the'system and associated telephone receivers which are disconnected electrically from the jackboxes when not in use and which can be plugged into the latter only by means of special portable key-plugs that must be procured from the ticket oice when buying an admission ticket. The key-plug in effect is rented for a specied period of use, which is usually for the duration of a daily public event.

A further object is to provide means for automatically locking the key-plugs in inserted position in the jackboxes in order to prevent unauthorized retention beyond the period of time contemplated in the implied rental agreement for subsequent re-use without paying for it. However, to admit of an arrangement whereby keyplugs may be rented for extended use, such as for a season of sports events, we have provided keyplugs of modied key characteristics which may be extracted by the spectator at any time and thus may be retained in his possession. Supplementary to the locking means, releasing means operable only by the operator of the public events establishment is provided to permit release and extraction of all key-plugs from the jackboxes at the end of each public event, after all spectators have gone.

A still further object is the provision of means associated with all jackboxes, whereby an operator at a central control location may electrically disconnect all key-plugs from the telephone receivers, release all key-plugs from the jackboxes, and cause the key-plugs to be conveyed by mechanical means to one or more collection containers. This feature is intended to make it unnecessary for attendants to make a tour of the seats for the purpose of gathering up the key-plugs.

Other objects and advantages of the invention Vwill appear as the following specific description is read in connection with the accompanying drawings, in which:

v Fig. 1 is a fragmentary plan View of a baseball stadium equipped with the spectator announcement communications system;

Fig. 2 is a diagrammatic view of the telephone receiver installation for a pair' of adjoining seats in the grandstand; Y

Fig. 3 is a fragmentary side elevation of a seat equipped with the individual spectator communication facilities unit, showing the telephone receiver suspended in condition of disuse;

Fig. 4 is a similar view, showing the jackbox in the first stage of movement into convenient position for plugging in the receiver and with the key-plug being held in readiness;

Fig. 5 is a similar View, showing the jackbox in final stage position `for the plugging-in operationLthe key-plug being shown applied to the receiver plug and about to be inserted in the jackbox sockets; I

Fig. 6 is a similar View, showing the jackbox restored to normal position with the receiver in position of use;

Fig. 7 is a simplified front elevation of the jackboX, showing the local receiver switch in closed, or on, condition;

Fig. 8 is a vertical sectional view of the jackbox, with diagrammatic representation of the electrical circuits,` showing the telephone receiver cord (broken away) plugged in and the d current turned on in the communications sy's'- tem;

Fig. 9 is a similar exploded View, partly broken away, with the operative parts shown in the condition wherein the local receiver switch is 'closed but the current has been turned ofi in the communications circuit system to eject the receiver plug from the key-plug;

Fig. 10 is a view similar to Fig. 9, with the operative parts in the condition wherein the communications current has been turned on again to'eject the key-plug;

Fig. 11 is a fragmentary transverse sectional View of the jackboX, with diagrammatic representation of the electrical circuits, showing the local switch in open condition;

Fig. 12 is a bottom plan view of the jackbox when the key-plug has been eiected;

Fig. 13 is a detail side elevation of a modified form of key-plug;

Fig. 14 is a fragmentary side elevation, on an enlarged scale, or" a seat arm with the individual spectator unit installed, showing the slideway for the jackbox in longitudinal vertical section, the receiver being shown plugged in but suspended in position of disuse;

Fig. l5 is a front elevation similar to Fig. 14;

Fig. 16 is another similar View, showing the slideway for the jackbox in transverse vertical section;

Fig. 17 is a view similar to Fig. 14, showing the jackbox in withdrawn, up-tilted position with the joined receiver plug and key-plug about to be plugged;

Fig. 18 is an exploded fragmentary View of the rubber-sheathed securing chain for the tele. phone receiver, showing the chain both in con tracted condition and in expanded condition;

Fig. 19 is a View similar to Fig. 17 of a modi-- fied form of the device, wherein a locked boxY houses the telephone receiver in condition of;

disuse;

Fig. 2O is a detail bottom plan view of the receiver box; and

Fig. 21 is an enlarged, `fragmentary sectional.

characters'of reference indicate corresponding parts in the several views, Fig. 1 represents adaptation of our spectator announcement system to a baseball stadium, although it is to be understood that we do not intend to be limited to use of the system in connection with any particular type of public event. The baseball adaptation is merely illustrative.

In accordance with the invention, it is proposed to install a telephone receiver unit A at each of the seats B which have been selected for spectator announcement service. The number of units and their location will depend upon local requirements Vas determined from preliminary estimation and later experience. It may be preferable at rst to restrict the installation to one or more sections of the grandstand.

In Fig. 1, the roof of the grandstand is shown broken away to reveal the receiver unit installation in a section directly behind the backstop. At a suitable location, and not necessarily anywhere near the receiver-installed seat section as shown, a control room C is provided for use of the special announcer for the system. This control room may have an adjoining room or compartment C to house the wire section of the electrical control apparatus, which will be de- 'scribed presently; and should be provided with"4 a window (not shown)A facing; theA playing eld so' that the special announcer may observe: as' much of" the action as possible Since it is intended: that' the special' announcer shall be ableV to utilize theservices of observers stationed at points of vantage along the side. lines of the' playing field where they'y may observe and report on close plays, rules invoked, and other incidents whichl it may noty be possiible for thespecial announcer'to* see clearly, al loudspeaker Dfisprovided` in' control room G forv electrical' connection with microphones; E'- lo catedV at thel said: points or vantage. For the baseballadaptationof the system, itmay beV preferable tc place the' microphones in thel vi'-I cinity of First Base', the Outeld, andi the Third?` Base-HomePlate line, as shown in- I. For" other public events, the disposition orY the obr servers? stations will depend upon theV nature of theY particular athletic sport, or the like, con--` cerned. When arrangements therefor are practicable, the servicesk of the'usually present'radiol or television announcers at their customary' ob'-A servation stations may be substituted for those or observers under direct control of the special announcer. Under suchv an arrangement', Ini-Y crophones E may be grouped with the microphonesv of the' radio' or television installation (not shown) or means-may be' provided for' con--Y necting the latter microphones witliloudspeak`l er Di I-f" a working arrangement withl the radioor television organization cannot be ei'ected, a radio receivingf set (not shown) may be includedI in theequipment of control room C for use of the special announcer, who may adjust it for reception of the local broadcast.

The control room is provided also with a microphone F for use in makingannouncements to the spectators, and with a switchboard G which serves asv convenient means whereby the special announcer may establish precisely controlled and coordinated electrical connectionv between various elements of the spectator announcement system. Likewise, through the medium-of'switchboard Cr, it is possible tov connect the communication circuits withV a source of electricity (alternating current) or-to shut off the current, at will. As shown in Fig. 1, line L for the current' supply enters switchboardv G preferably through wire compartment C. The switchboard is shown as being connected with the receiver units-A by main line L" andr itsbranches L", which latter preferably are connected in parallel to line L' and may be extended along the rowsof seats B served by units A. Each line of the total communications system preferably comprises a pair of conductors consisting of a primary operating circuit topermit electrical connection with specific secondary circuits of the individual receiver units a manner which will be described l'aterherein. The master switch M shown in Fig. 8 is locatedV in control room C for use by the announcer in turning the` current for the entire system on andoi.

A general idea ofthe construction of a' seatinstalled receiver'unit A- may beV gained from the external appearance thereof as disclosed in` Figs; 3-tov Ginclusive. The principal elements of the unit are jackboxA 30 and telephone receiver 3'I`, which latter preferably is of the headset' type shown. A convenient out ofthe way location for the unit is under one arm B of seat B; For reasons which will appear presently, it is' preferred to mount jackbox 30- adj'ustably so that it may be: pulled forward into. the cross; aisle be= tween seat rows, as shown in, Fig- 4; and,- then;v

swungupward through an anglel ofV substantially 9'0 degrees into the. position of Fig. 5. Provisionfoi` this adjustment; has been madeby aihxing a. lengthwise slideway- 32- to the underside of seatv arm B". This slideway preferably hasV the crosssectional shape4 shown particularly in Figs. 15.L

3U, (Figs. 3 and 6), the rear external face of. the*l latter abuts the preferably square-cut frontl end. ofV slide-bar 33 and thereby. affords lateral sup-- port forl said: jackbox.

In order tofacilitatev manipulation of.' the jack-- box, a handle131' has been provided on thel lower front corner thereof. The location of handle 3-.'lf is' also well suited for cooperationY with thev means by which telephone receiver 3| and its'Y il'exible cordv 38 and` connector plug 39 are permanently secured to jack-box 30' to prevent unauthorized removal. from the seat B with which the unit isV associated. The specificv securing means preferred is an elastic, contractible member 40, which,v as'v disclosed in Fig. 1-8; is composed of chain. lift and tubular sheathing t2'. The latter is: made ofv rubber or other elastic material, sov that'. it may be stretched to elongate flexible member 40` as a whole under certain conditionsoi` usewhich. will be explained hereinafter. Elongation; of member 40 is permitted by using achain having elongated links which telescope in effect when the sheathing 42 is contracted in length. The ends of sheathing 4l!V should be fixedly securedf to the terminal links of chain 4l in some suitable manner, as bymaking the said ends constricted in diameter; In Fig. 18, the left-hand fragment of member 40 is shown in normal contracted condition, whereas'the stretched condition is shown at the right. The terminal chain link at one end" oiv member 40 preferably' is secured xedly to the outermost portion of handle 31 andthe terminal link at the other end is secured in like manner to connector plug 39. It is essential. to the operativeness ofl certain functional. parts of the receiver unit that, in the normal condition of member 40, (Figs. 3` ande), connector plug 39 shall-be suspended below the level of jackbox 30 but in laterally'y spaced relation to the central area of the bottom face thereof so as to clear the space'beneath thesame for a purpose to be made known later herein. For convenience in suspendingL telephone receiver 3i in an out of the way position when not in use, a spring clip 43 may beV provided on the underside of slide-bar 33l Referring now to Figs. l to 13v inclusive, it will be noted, that connector plug 39 of telephone receiver 3i is of standard type except for sleeve M"` which projects: from its outer end in partially enclosing and spaced relation to contact prongs 45, 46. Although said contact prongs 45, 46 may be plugged into a standard electrical outlet, they will' not t the sockets in jackbox 3! which are of a special' kind to be described later. In accordance with the principle of our invention, it is necessary to interpose a special key-plug 4l between the receivers connector plug 39' and j'ackbox- 30'. As previously explained, this keyplug must beirented by al spectator'in order that he 'may' take advantage of the spectator an` nouncement service.

Key-plug 41 has a body 48 of non-conducting material, such as hard rubber, Bakelite, or the like, which preferably is flat and elongated in shape to match as nearly as practicable the size of an admission ticket and thus facilitate storage, issue and transportation. In one end of body 48 Vthere are sockets 49, 50 adapted to receive contact prongs 45, 46 of connector plug 39. Suitable female'contacts 5 I, 52 embedded in sockets 49, 50 of key-plug 41 are adapted to frictionally engage contact prongs 45, 46 when the connector plug and key-plug are united. In this condition, sleeve 44 embraces substantially half of body 48 of the key-plug and shields the same from direct grasp by the hand of the spectator when plugging into jackbox 60. The reason for this provision will appear later. Specially shaped contact prongs 53, 54 project from the end of body 48 of key-plug 41 opposite to sockets 49, 59 and are preferably integral with contacts l, 52 respectively. Contact prongs 53, 54 are shaped to t sockets 55, 56 provided in the bottom wall of jackbox 39. Sockets 55, 56 actually are formed in a block 51 of non-conducting material, which will be termed the socket member of the jackbox. Fixed female contacts 58, 59 are embedded in sockets 55, 56 for frictional engagement with contact prongs 53, 54 respectively of key-plug 41.

To provide further security against unauthorized use of the receivers connector plug, such as might be accomplished by twisting its Contact prongs into formations which might permit insertion thereof into sockets 55, 56, contact prong 54 has g,

been made considerably longer than contact prong 53 and xed contact 59 has been located correspondingly further from the exposed face of socket member 51 than fixed contact 56. Fixed contacts 56, 59 are electrically connected with binding posts 60, 6I, which are located preferably on the inner end of socket member 51 in spaced relation to the central area. thereof. Binding post 66 is connected to the inner terminal of electrical conductor 62 which is paired with conductor 63 in a lead 64 extending from jackbox to a suitable point of connection of conductors 62, 63 to the respective conductors of branch line L of the communications system. Binding post 6I is connected with the terminal of an electrical conductor 65 which leads to one single pole 66 (Fig. 1l) of a 3-way snap switch 61 mounted in the front wall of jackbox 30. The double pole 66 of switch 61 is connected with the inner terminal of conductor 63 of lead 64. When the exteriorly presented manipulating knob 69 of switch 61 is turned into the on position shown in Fig. '7, the movable switch contact arm 10 rigidly united to said knob will bridge poles 66 and 68 and thereby close the line circuit to telephone receiver 3l through keyplug 41, connector plug 39 and cord 38. Fig. l1 shows switch 61 in the off position, wherein arm 10 bridges double pole 66 and a second single pole 1I which is connected through impedance element 12 to conductor 62 of lead 64. The impedance, or effective resistance, of element 12 should be equal to that of telephone receiver Si and the circuit leading thereto so as to prevent fluctuation in the load imposed on the communications system as receivers are switched on and off in the normal operation of the announcement service.

Before proceeding further with description of the internal mechanism of jackbox 30, mention will be made of four special functions which are to be performed by thatmechanism in addition to electrical connection of the telephone receiver with the communications system. Those functions are: (1) automatic locking of the key-plug in plugged-in position; (2) preliminary ejection of the connector plug of the telephone receiver from engagement with the key-plug; (3) subsequent unlocking of the key-plug; and (4) nal ejection of the key-plug from the jackbox. The second, third and fourth functions are performed by the special announcer through operation of a master switch in the control room at the end of the game or other public event and after all spectators have vacated the stands. Simply unlocking all key-plugs simultaneously would suffice to permit collection by manual withdrawal from the jackboxes for return of the key-plugs to the ticket ofce, but we have made provisions for automatic release and conveying of the key-plugs to central collection points more readily accessible to the ticket oflice. The announcer-controlled unlocking and ejecting of the key-plugs cooperates with conveying means which will now be described.

Referring again to Figs. 3 to 6, it will be seen that a vertical conveyor chute 13 extends downward from a flared mouth 14 thereof located directly under the key-plug sockets in the bottom of each jackbox 39. This chute 13 leads into a system of conveyor chutes, as shown particularly in Fig. 3, which extend to one or more collection receptacles (not shown) located at a lower level in the stands, where stadium attendants may gather them up for return to the ticket office with far less effort and expenditure of time than would be required for a tour of the seats to withdraw the key-plugs from the jackboxes by hand. rEhe reason for the contractible feature of securing member 49 and its attachment to the laterally displaced handle 31 of the jackbox should now become apparent. There is sufficient space between the mouth 14 of chute 13 and the bottom cf jackbox 36 to accommodate the plugged-in receiver connector plug 39 and key-plug 41, Vas shown in Fig. 6, but it is essential that plug 39 shall be moved out from under key-plug 51 as soon as plug 39 is ejected from the latter in order not to obstruct gravitation of the key-plug into the chute mouth when the said key-plug is subsequently unlocked and ejected from the jackbox sockets. Contractible securing member 40, which is expanded and under tension when the telephone receiver is plugged in (Fig. 6), will contract and pull plug 39 out from under key-plug 41 and clear of the mouth of chute 13 immediately upon ejection of plug 39 from the key-plug. Fig. 3 shows this chute-clearing position of plug 39.

Turning again to Figs, '7 to 13, the ejecting means for both plugs and the locking means for the key-plug will be described. Key-plug 41 has a centrai, longitudinal bore 15 in which a metallic cooking plunger 16 is sldably mounted. Plunger 16 is maintained normally in the position shown in Fig. 10, wherein the forward (upper) end thereof projects outward a short distance, by spring means 11 which maintains the said plunger in a state of equilibrium subject to displacement in either direction longitudinally with respect to the key-plug. Inside jackbox 59, a metallic ejector bolt 18 is slidably mounted in a central, axial, through bore 19 in socket member 51 and in aligned upper and lower bearing brackets and 8l respectively, which brackets are made of non-conducting material similarly Lto said socket member. Bore '19 is in a position wherein it will :be aligned with the cooking plunger 16 of any key-plug .that is plugged into the jackbox. The diameters of each cooking plunger 16 and ejector bolt 18 .are the same in order that the former may enter bore 19 in socket member 51 as the key-plug is plugged in. The normal shot position of ejector bolt 18 is shown in Fig. 10, wherein the outer (lower) end of the said bolt is substantially iiush with the bottom face or" `-socket member 51. In this position of elector bolt 18, an adjustable stop collar-82 of conducting material carried by said ejector bolt will be .in contact with an velectrical contact ring 83 which is mounted on the upper face Vof bearing bracket 8| with its inner periphery spaced from `ejector -bolt .18 to preventelectrical contact between contact ring 83 and ejector bolt 18. Spring means .84 tends to maintain ejector bolt 18 in this shot position. Spring means 84 preferably is in the form of a compression .spring interposed between bearing bracket 8| and a collar 85 of conducting material which .is adjustably secured to ejector bolt 1.8 .as by set-screw .86. This set-screw V|56 `.additionally serves as an electrical binding post .for attachment of the terminal of .a conductor which leads .to conductor 62 of lead 64. The .tension of spring 84 .may be varied to regulate the .ejection force applied to ejector bolt 18 by .adjusting the set position of collar 85 on said bolt.

When the cooking plunger 16 of a key-plug is forced into the lower end of bore 19 in socket member 51, the said plunger' will push ejector bolt .1.8 upward. In order to obtain the desired upward .displacement ofejectoribolt 18, the connector plug 39 of the associated telephone receiver 3| must irst be plugged into key-,plug 41, so 4that cooking plunger .16 will .besustained in its upwar-dly .protruding position of Fig. 1'0. that sleeve 44 is provided on connector plug 39. If a spectator, who .usually will have no knowledge of the manner` in which `the jackbox mechanism functions, found it convenient .to grasp the keyplug alone when plugging in, .the cooking plunger 16 would back up in the key-plug `bore upon being brought to Vbear against the lower end of ,ejector bolt 18 instead of pushing the latter upward inthe jackbox yas desired. 'The extensive sleeve 44 .insures that connectorplug 39 will be grasped and pushed upward, whereupon the upper end face of plug '39 Ywill sustain cooking plunger 10 `in `its normal position (Fig. 6). As a result, ejector bolt 18 will be moved upward into the cocked position represented in'Fig 8.

Ejector bolt 18 has a catch V8 0 of .non-.con- 'I ducting material secured 1in any suitable manner `to its upper end. Catch 88 is preferably of the frustoconical form shown so as to provide a perpendicular underneath catch `face 89 .and a tapered peripheral Acam face 90 for Acooperation with the Ylocking point '9| of a detent 92 which .is pivotally mounted on axis 92' in ,jackbox `30.

Due to the specific shape ofcatch 88, faces 89 and 90 will always be properly presented .to lockf'ing point l'9| regardless of any incidental rotation yofejector bolt 18 in itsbearings. Spring means '93 tends to maintain detent 92 normally in the position shown in Fig. 9, wherein locking point 9| will ybe clear of the path of catch 88. Mag-- lne'ticfmeans by which detent 92 may be moved `into the position shown in Figs. 8 and 1'0 wherein locking point 9| is in thepath of catch r80, may take vthe form of alternating current solenoid 94. This solenoid, which may be termed the Itis for this reason f noid.

.telephone receiver 3|.

rjackbox .3.0.

ejector bolt solenoid, is `connected preferably in parallel with conductors 62 and63 of lead 04, so that, when the current is turned on in the communications system, the said solenoid will be energized regardless of whether switch 61 is in "on or off position. The -core`95 of solenoid 94 has its inner .end suitably connected .as at k.96 to detent 92, which latter should be made of non- -magnetic `material so as not to disturb the desired balanced position of core 9,5 when the solenoid is energized.

Automatic locking of key-plug 41 in pluggedin relation to jackbox .30 is accomplished preferablyby use of a. .detent 91 which is integral with one end of the core 88 of a second solenoid 99, which will be known `as the key-plug lock sole- Detent 91 lis slidably tted in a radial bearing opening :'00 provided in socket member 51 in registration with `socket 56 below female zcontacti. The longer contact prong 54 of keyplug 4'! is provided with a locking notch 10| adapted to be engaged by detent 91. The extremityof contact V.prong 54 has a cam nosing |02 formed thereon for wedging contact with detent 91 to force the latter outward and clear 4of .the said prong during the Vact of plugging in. Spring means |03 tends vto `force detent 91 `inward into locking position within socket 55. The terminals of the coil of solenoid 99 are connected respectively to contact ring 83 .on bearing .bracket 8| and to conductor v63 of lead 4. Energization of solenoid 99 will cause outward movement Yof detent 91 against the -action `of spring means |03.

Fig. 13 shows a special key-plug which may be rented for repeated use lof the esame person, such as for a series or season of .sports events. It has the locking .notch |01 'alter-ed to -provide a cam face |04 on the side thereof nearer Vthe extremity of contact prong 54. This second'cam face will cause deflection of detent 291 into vthe vtripped position shown vin Fig. vl0 whenever the spectator-chooses vto manually withdraw plug from the jackbox sockets.

Figs. 14, 15 and V1'1 disclose a modiiied fea-,ture

the key- `of vjackbox 30, `inaccordance with which-exterior guard flanges |05 Adisposed substantially in `the planes of therespective side 4.walls-of the jackbox are joinedto handle 31. vThese guard'iianges protect vthe manipulating knob 89 of switch r6-1 and key-plug .41 when plugged -in from being hit 4and .disturbed or `damaged accidentally -by spectators when moving about during the game or other public event. The flanges also strengthen handle 31 vand shield securingmember 40 which is attached to said handle.

Figs. `19 tto 2l fdisclose .wherein abox |00 `is Yprovided -on Ythe underside .of .slide bar 33 to -house and thus better protect Box |06 has no'front wall, but the opening thus provi-ded is adapted to 'be Aclosed by a swinging door :|01 which has hinge elements 88 .incorporated inthe hinge I34 for A notch |09 has been provided in ,the lfront edge of thebottom wallof box H16 to accommodate receiver cord .38. A stop member H0, such as the .ring shown, may be secured to cord 38 at such a .distance fromconnector plug '3S that all the slack portion or" cord 38 .may be housed with receiver .3l :in .box |06 .and will be prevented fromslipping out through notch |09 when door vlill is in closed position. -Latching meansfor door |01 may be provided in the form of Ya. spring-pressed vertical bolt 1| iwhose flower end is adapted to engagea locking recess V|I2 in the bottom wall of box |08. Latch bolt f|| I a further modication i should be offset laterally from notch 109. The

upper end of bolt Ill is pro-vided with a horin arm B (Figs. 3, 6, 14 and l5), the said lever is jointed medially as shown particularly in Fig. 21. This joint is suitably built into hinge 34 and includes shoulders H5 and HT, which are adapted to abut each other as shown in full lines when jackbox 313 is moved into the position shown in Figs. 5, 17 and i9 for convenience in plugging in the key-plug. VWhen shoulders IE6 and lll are in abutting relation, movement of ejector bolt 'I8 to the left (Fig. 19) will cause lever H5 to rock as a whole counter-clockwise and thereby deflect cam follower l I3 upward so as to unlatch door |01. Shoulders H5 and lll will separate, as shown in broken lines, when jackbox 30 is restored to inswung position. A relief opening H8 is provided in door |01 to receive cam projection I I4 when it is actuated by ejector bolt i8. When jackboX 30 is inswung to the point that door I'l is forced shut, the rear Wall of said jackbox will strike cam projection H4 and thereby force it inward to release latch bolt Hl, which will then be restored to latching position.

The operation of our spectator announcement system in its adaptation to a baseball stadium will now be described by way of illustration. At a proper time before the game starts, master switch M is closed by the special announcer. The immediate effect is to energize the ejector bolt solenoids 94 of all jackboxes, so that the detent 92 in each jackbox will assume the position shown in Fig. in the path of catch 88 on ejector bolt 18. Each jackbox is now electrically live and mechanically ready for use of a spectator who is in possession of a key-plug of either the daily rental or the season rental type.

When the spectator arrives at his seat and is ready to listen in to the announcement service which may be in progress, he reaches down with his right hand for handle 31 and pulls j ackbox forward and upward until it is in the position shown in Figs. 5, 17 and 19. In this position, the sockets for the contact prongs of the key-plug will be exposed to the spectators view so that he can see what he is doing. It will be easy now to include connector plug 39 of the telephone receiver 3l in the grasp of the right hand and to insert the contact prongs of plug 39 into the sockets of key-plug M, which latter may be held in the left hand at this time. When this has been done, the left hand may be used to hold the jackbox handle while the two united plugs are aligned with the jackbox sockets by the right hand, in which operation securing member will be stretched into the condition shown in Figs. 5 and 17. Now, the key-plug prongs are inserted into the jaokbox sockets and plug 39 is pressed rmly against the key-plug so as to cause cooking plunger 1B to force ejector bolt 'I8 upward into the cocked position shown in Fig. 3. While moving into this position, cam face of catch 8S will deiiect the locking point Si of detent 92 laterally until it is cleared by catch 88, whereupon the detent will be forced inward by the action of the ejector bolt solenoid 94 until locking point 9i becomes engaged beneath face 89 of catch 88. Likewise, during this movement of the ejector bolt, the key-plug will become locked automatically in position by engagement of detent 9i with notch i5! in contact prong 5d.

In the embodiment of the invention disclosed in Figs. 3 to 6 and 14 to 17, the telephone receiverwill be suspended by clip i3 under the seat arm. After the receiver has been removed from its supporting-means, the jackoox may be lowered and slid back into its normal out of the way position, in which the spectators control switch 51 will be readily accessible on the front face of the jackboX for use in connecting the receiver with the communications circuit or in disconnecting it, as desired.

If the modified form of the receiver unit shown in Figs. 19 to 2l is used, the receiver 3l and its cord 38 will be locked inside box it@ between games and until the key-plug has been plugged into the jackbox. When this has been done, ejector bolt '18 will unlatch door iii? when the said bolt moves into cocked position and transmits the necessary motion through lever H5 to cam projection Mii. Thereupon, the spectator may withdraw the receiver from the box. When the jackboX subsequently is restored to normal position beneath the seat arm, the doorto box li will become latched automatically. However, if the spectator later decides to replace thereceiver in box |35, movement of the jackbox tothe outswung position of Fig. 19 will unlatch door It? to permit this to be done.

Throughout the game, thespecial announcer is enabled by use of the apparatus described to furnish interested spectators with a running account of the action, interspersed with reading of any new rules which may be invoked. In describing the action, he may rely upon his own observation, but is always prepared to connect the systern with any one of the field microphones when he feels that the action may be observed more clearly and reported upon more accurately by the observer stationed at that microphone. Similarly, he may listen in on the current radio broadcast and possibly obtain information to clear up some incident not clearly seen nor understood from the control room window. In this way, the special announcer is enabled to keep his local audience accurately informed on all incidents of play. The radio broadcast may even be cut in on the local communications system on occasion, when appropriate, such as when announcements are being made of the arrival or presence ofdistinguished spectators or when reports are being broadcast as to current standing of teams or the final results of games being played in other parts of the country. This service is of even greater importance in the case of football games. As an incidental use of the local announcement system, the special announcer may request spectators to restore their telephone receivers to the supporting clips or storage boxes, as the case may be, toward the end of the game. In fact,V the system is capable of unlimited variations in useA in connection with all sorts of public events, especially when under the control of a versatile special announcer.

After the end of the game, when it is safe to release the key-plugs, master switch M may be opened to cut oi the current for the communications system. When this is done, the ejector bolt solenoid in each jackbox will be de-energized, whereupon spring means 93 will trip catch 88 and thereby release ejector bolt 18. which will .fdescend as showninxEigxQ into :contact with :cooking plunger 1.6 in the key-plug. ,'.Thekeyeplug Lwill-still beLlocked-.-in..the jackbox, so -plunger;"l6

will be driven.. downward into contactV with ccnnector plug 2139 land Will -ejectathelatter from .plugged-inengagement with the :keyeplug VAt S the same time, spring meanssf84fof'ejectorbolt 118 and thefweightof said'bolt will .placespring lmeans t1 'I of fthe.` key-plug under :tensionand -will 'maintainit in this-condition;temporarily. De-

scentof the ejector' bolt willibring.stopzcollarigBZ into contact :with contact ring .-83.and .thereby electrically connect: .key-plugl locking .solenoidii v.with conductors VB2 and 263 of i lead.-4, in A:which connectionthe portion of ejectorbclt-whichr ex- Atendsbetvveen contact ring-83 andcollar 85fforms Vpart of the electrical. circuit. VAfter .this condi- .tion has been established, master switchM may again be closed, 4whereupon:solenoiddifl will'become energized Aand lcc-ringdetent 9T will .be

4Withdrawn-irom engagement with notch [el vin prong 54 ofthe key-plug. 'When this happens,

spring means 71 in the key-plug `willzreact .to ejectlthe .key-plug forcibly downward into the mouth of conveyorlchute i113. Finallypmaster switch M is openedfor the second timetoshut loir the current until the next game.

The combination ofV an electrioalf key-plug with a cooperating outlet socket hasy wider*A application than the presentlygproposed use in the receive'.-

unit ofa communicationssystem. -For instance,

lthis invention could IWell be used-to replace the -coin controlfor clotheswashers of the Laundermat type. YIn that application, each of the Washers of the usual battery wouldlhave a standard connector plugon the end -of alexible cord-cor- --respon'ding-to the-plug lSe andcord 38 of our telephone receiver. lA key-plugidentical with-our plug-'llwculdbe rented tousers of V't-hevvashers to establish'an'electrical connection-'between connector plug of a washerfand -a wall outlet having special key-shaped socketswhich will-fit the key-plug but not thewashers'standard plug. Anotherjapplication.Wculdybe in a trailer park,

Where trailerownes.whofengage parking space` have to plug :theirelectric light, cooking, and other circuits into an outside source of current under thecontrol ofthe paikowner. The keyplug feature could be adapted to metered outlets havin-g'- the specially shaped sockets It-isto be understoodthat the term field: as

used in fthe specication and appended :claims lmeans the playing eld, ooigarena, orrot-herf'area :where the action of a `A.sports event occurs. Similarly, the same term refers to the ring or lother exhibition area of an-animal showfr to the landing eld or generalfoutlying:areasuch as is dened by the turn pylons of an aircraft show, demonstration, .or racing event.

Whenever the term transmitter is usedit is intended to embrace .telephone transmitters,

14 closeds are illustrativeonlytand may be` modified 'in ,many vrespects vWithout departing from ethe Vspirit .and scopelof :the vinventive VVconcept tas lpointed .out in and .limited :by the-.appended claims.

Havingjthus described* the invention, whatwe claim as new and desireto `secure byLetters Patent is:

lfIn. an electrical system includinga'primary operating circuit .and switching .meansy therefor; Aa jackbox including a socket memberhaving outlet vsockets of vspecial key-sharia. electrical vcon- Ytacts embedded in said sockets-andV being connectediviththe primary operating circuit, a connector` plug adapted to be connected with arsec- :ondary circuit and having standard contact prongs; :a key-:plug including a body having standard sockets thereinadapted to t the conftact-prongs of the secondary circuit connector Yplug,-electrical contacts embedded in the sockets of thekeyfplug, zand contact'prcngs connected with said electrical contacts'of the key-plugf-and ioeing specially key-shaped'to fit the sockets of the outlet Asocket member of the jackbox;`locking ,Y means provided in vthe'jackbox vfor engagement .with the key-plug when plugged in, means tend- 'ing tdmaintain Vthe locking meansin'locking condition, vand-means actuated byY changing the electric current `condition off the: primary operating circuit whereby the locking means maybe released to free the'key-plug.

2. A'device-of thev character defined in claim l, .wherein the locking means fior the key-plug includes a detent movablymountediin the j-ackbox and Ywherein one-contact prongof the key-'plug L has a side notch engageable"bysaiddetentl 3. 'In an electricalfsystem including a-'primary operatingv circuit'lan'd switching means therefor; -a jackbox includingfafsocket member havingout- .let sockets of "special key-shape, electrical` contacts embedded in -said sockets and being connectedl Withthe prima-ry: operatingfcircuitga connector plug :adapted to be connected V.with a Asecondary circuit `and having standard contact prongs; a key-plug including a body having vstandard sockets therein adaptedto t the con- -tact prongs'of fthe `secondary circuit connector :plug-'electrical contacts embedded in thescckets of the =keyplug,fand contact prongs connected :with said electricalcontacts-and being of special -fkey-shape to fit thefsocketsof saidfoutlct'socket :'memberof the jackbcx, ,theLkey-plug body bei ing :provided with ya lthrough bore disposed with its ends facing'in thefdirec'tion of the :sockets aand contact prongs respectively, a plungerfslir'- :ably :mounted in :said bore, :spring lmeans tend- .'ing `.to resist flongitudinal thrust Vof the :plunger Vin either directionin saidbore; thesccketmem- 'berof the jackbox'fbeing provided'withfa bore adaptedtol-bea'ligned with the plungerlbcre-inithe key-'plug when plugged into vthe voutlet sockets, .an :ej ector Ibolt. slidably mounted :in said fscc'ket member bore and adapted to be contacted by and thrust longitudinally inward into cocked position by the key-plug plunger during plugging in of said key-plug, spring means tending to drive the ejector bolt outward and thereby impart thrust to the key-plug plunger to eject the connector plug from connection with the keyplug, means for locking the ejector bolt in cocked position, and means responsive to opening of the primary operating circuit for releasing said ejector bolt locking means.

4. A device of the character defined in claim 3 wherein the locking means for the ejector bolt `'comprises a catch on said bolt, a solenoid connected electrically in the primary operating cir- 'cuit and having its core disposed to lockingly engage the bolt catch in the energized condition yof said solenoid, and spring means tending to move the solenoid core into tripped position out Vof the path of the bolt catch.

`3 wherein one contact prong of the key-plug has a locking' notch and means is provided for locking the key-plug in plugged-in relation to the jackbox including a solenoid having its core engageable with locking notch oi the key-plug contact prong, spring means tending to maintain said key-plug locking solenoid core in locking position, and means actuated by the ejector bolt for connecting said key-plug locking solenoid electrically in the primary operating circuit when said bolt is `shot into ejecting position whereby the key-plug will be released when the current in the primary operating circuit is turned on again after being turned off to release the ejector bolt.

7. A key-plug of the class described comprising a body having standard outlet sockets in one face thereof, electrical contacts embedded in said outlet sockets, special key-shaped Contact prongs projecting from the opposite face of the body and being connected with the respective contacts, the body being provided with a through bore extending between the said opposite faces thereof, a plunger slidably mounted in said bore, and spring means interposed between the key-plug body and the plunger for resisting longitudinal thrust of the plunger in either direction.

8. In an electrical system including a primary operating circuit, a support including a horizontal slideway, a slide-bar sli-dably fitting said slideway, a jackbox having its top part also slidably fitting said slideway and its upper inner corner hinged to the forward en d of the slide.. bar, the jack-box being provided in its bottom wall with outlet sockets adapted to be exposed in forwardly presented position for a users view during plugging-in by sliding the jackbox forward and swinging it upward on its hinge, a connector plug for a secondary circuit permanently secured to the jackbox and having standard contact prongs, a key-plug having sockets of standard shape in one face thereof adapted to t the contact prongs or the secondary circuit connector plug, electrical contacts embedded in the key-plug sockets, contact prongs of special key-shape projecting from the key-plug oppositely with respect to the sockets and connected to l5 said electrical contacts and being adapted to fit the outlet sockets of the jackbox, the key-plug being provided with a through bore extending parallel to the contact prongs thereof, aplunger slidable in said key-plug bore, spring means for resisting end thrust of said plunger, an ejector bolt slidable in the jackbox and adapted for alignment with the key-plug plunger when the said key-plug is plugged into the jackbox sockets, the key-plug plunger being adapted during plugging in motion to thrust the ejector bolt inward into cocked position, spring means tending to force the ejector bolt outward and cause plug ejecting force to be transmitted through the key-plug plunger to the secondary circuit connector plug, means for automatically locking the ejector-bolt Vin cocked position, means for locking the keynecting the said connector plug to a part or" the jackbox laterally offset from the outlet sockets and being adapted to be placed under tension when the two plugs are united and plugged into the said outlet sockets whereby the said connector plug will clear the ejection path or the keyplug prior to delayed ejection of the latter from the jackbox sockets.

10. A device of the class deiined in claim 8 wherein a box to house the receiver is mounted in depending position on the said slide-bar, said box having its front wall open, a door hinged to the box vto close the opening, latching means for said door, and means actuated by cooking of the ejector bolt in the jackbox for automatically unlatching the door latch.

EDWARD R. MELLDTGER.

RUTH E. MELLINGER. DUDLEY B. HOWARD.

UNITED STATES PATENTS References Cited in the ille of this patent Number Name Date 1,058,032 Campbell Apr. 8, 1913 2,002,177 Hastings May 2l, 1935 2,152,647 Hubbell Apr. 4, 1939 2,199,560 Faller May 7, 1940 2,551,533 Gernheuser May 1, 1951 2,562,592 Woodside July 31, 1951 FOREIGN PATENTS Number Country Date 363,487 Germany Sept. 16, 1921

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