US2448832A - Pin anchored electric outlet and switch - Google Patents

Description

Sept. 7, 1948. D. s. Ross PIN ANCHORED ELECTRIC OUTLET A ND SWITCH 3 Sheets-Sheet 1 Filed Sept. 14, 1945 :inventor aan/Am 5. H055 Sept 7, 1948. D. s. Ross 2,448,832

PIN ANCHORED ELECTRIC OUTLET AND SWITCH Filed Sept. 14. 1945 3 Sheets-Sheet 2 7 \\\\L 75 60 U l/ I 61 Q 63 I @55a 65x el* ..88 83 5o 52 5 ao 5 54 o 86 O i 3 o o O 89 86 K8 57 55 88 C Imventox:

00A/4M s @Q51 (Ittrnegr Sept. 7, 1948. D. s. Ross 2,448,832

PIN ANCHORED ELECTRIC OUTLET AND swITcH Filed sept. 14, 1945 3 Sheets-sheet 3 We@ LM E5: f5

Gttornegx Patented Sept. 7, 1948 PIN AN CHORED ELECTRIC OUTLET v AND SWITCH l Donald S. Ross, Moclips, Wash. Application September 14, 1943, Serial No. 502,281

16 claims. (c1. 20o-51.09)

My present invention relates to outlets generally ilush with a floor -or wall surface with imn perforate exterior surfaces, and to outlet blocks suitable for use with such' outlets, which in many respects are similar to the flush type outlets and blocks disclosed in my Patents Nos. 2,234,982, issued March 18, 1941, and 2,298,313, issued October 13, 1942. My present invention, however, diifers in import-ant particulars from the devices disclosed therein.

Such flush type outlets are wholly imperforate, thus leaving no holes, depressions, or apertures of any sort wherein dirt may collect, nor through which the line can be contacted or grounded. Thus they are particularly suitable for floor installations. Current is transmitted from the leads beneath the oor to the outlet block, and thence to the current consumer, by contact be'- tween terminals ush with' the floor surface and with the surface of the applied outlet block, respectively, usually accompanied by closing of a switch actuated by such operative positioning of the outlet block, or the current transmission may be inductively accomplished. In either case rather accurate location of the outlet block upon the outlet is necessary, and this location must be maintained, against any tendency to lateral displacement of the outlet block. Such maintenance of positioning has been accomplished heretofore by transmission of yan attractive force perpendicularly to the floor, magnetic, suction, or the like in nature, between the outlet block and the outlet. A more `positive position-maintaining means is sometimes desirable, though it must still leave the outlet flush and imperforate when the outlet block is withdrawn. Th'e provision of such position-maintaining` means, ordinarily wholly divorced from the current transmitting means, is the primary object of this invention.

Ingeneral, therefore, my present structure was devised to anchor the outlet block positively against accidental displacement along a oor, for example, even though the outlet itself is imperforate and has noprojection or depression to interengage with' or to hold the outlet block. At the same timeconstructions having these advantages should be adapted for embodiment in both the switch controlled and the constantly energized varieties of outlet. If a switch is provided it may be either of the normally open type or capable of being held closed automatically.

The construction adopted employs piercing points which' when the outlet block is operatively applied to the outlet project from the 'one to penetrate resilient blocks carried by the Iother. It is undesirable to leave these piercing points projecting when the outlet block is purposely (or inadvertently) removed from operative position. While they may be, and in most cases are, divorced from the current transmission means, t@I- 2 leave them projecting invites damage to them; and injury to persons. Particularly `is it un` thinkable to leave them projecting if they are mounted in and project from the outlet inthe floor, for this is then no longer a ilush `type outlet; still, it is almost as undesirable to leave them projecting from the outlet block. It is a further important object to provide such position-maintaining means which, by the action of disengaging the outlet block from the outlet, are auto-` matically withdrawn into their mounting, either the outlet block or the outlet, as the case may be. `While the position-maintaining means, the piercing points mentioned above, are ordinarily divorced from the current conductors, or from switch-operating mechanism, their abilityto perforate the surface of the outlet, for example, without leaving a permanent hole therein,` makes possible their utilization as current conductors or as switch operators, in some instances, though still retaining their ability to retract automatically upon withdrawal from operative engagement. A further object of my invention is to achieve such advantages by mechanism which' is of simple and inexpensive character. Moreover, the principles of operation of my device are capable of being incorporated in a wide variety of different outlet structures, and certain of these may be constructed deliberately so that a varied selection of outlet blocks can be used with a single type of outlet, or, on the other hand, one outlet block can be used in conjunction with a number of different'outlets, depending upon the type of installation and the characteristics of operation desired. l A variety of outlets and outlet blocks are disclosed in the drawings and described in detail hereafter as examples of various embodiments of outlets-outlet blocks, and combinations thereof constructed in accordance with my invention. It will be'recognized that structures 'differing considerably in detail lcould be used in most in` stances and still obtain the same results, and such modications of the devices illustrated for the most part will be apparent to those skilled in the art according tothe particular installation or use for which they may be designed.

Where such points are used as current conductors it is also an `object to prevent them from being injured by engaging electric terminals which are energized at the time 'of contact. It is desirable in many cases, however', that the outlet block be energized automatically immediately following its application to the outlet, and my invention affords such operation. Additional objects of my invention, and examples of ways in which th'e above mentionedobjects may be achieved, will be understood from the following description and the drawings of 3 several exemplary outlet and outlet block constructions.

Figure 1 is a longitudinal sectional view through one form'of outlet and outlet block, while Figure 2 is a transverse sectional view through the outlet block taken on line 2-2 of Figure 1.

Figure 3 is a longitudinal sectional view through a dilerent type of outlet to which the outlet block of Figures 1 and 2 may be applied.

Figure 4 is a longitudinal sectional view through another form of outlet and outlet block, and Figure 5 is an end elevation view of such outlet block, in condition for application to an outlet.

Figure 6 is a longitudinal sectional view through an outlet and outlet block of still a diiferent type, while Figure '7 is a transverse sectional view of the outlet block on line 1 1 of Figure A6. Figure 8 is a longitudinal sectional view through a further form of outlet and outlet block, which block may be used with the outlet of Figure 6, and which outlet will accommodate theoutlet block of vFigure 6. Figure 9 is a detail sectional view of latch parts in positions diierent from those of Figure 8.

Figure 10 is a longitudinal section through another outlet and outlet block, Figure l1 showing the outlet block .in elevati-on removed from the Outlet. Figure 12 is a fragmentary bottom plan viewy taken from line I2--I2 of Figure 10.

Figure 13 is a .longitudinal sectional view through an yadditional modification of my invention. :Figure 14 is a top perspective view of the outlet, Awith' the outlet block removed. Figure 15 is 'a transverse sectional view through the outlet block taken on line I5-I5 of Figure .13.

The principal characteristic of Vall the various forms of my invention illustrated is the use of piercing poi-nts, pins or needles which are forced into a Ponetrable surface of the outlet for one or more purposes. Such surface may be any one of various soft, self-sealing materials, but rubber or Similar substance is 'preferredvAllv of such pins positively interconnect the outlet block and the outlet so that the block cannot be slid laterally out of registry with the outlet. In the struc-r ture of Figure 1, for example, the outlet block has points I piercing `buttons 2 embedded in the plate `2l) of the outlet, which is set into the lloor F flush with its upper surface. In this particular type of outlet th'e pins perform the additional function 0f closing normally vopen :switches 3 by direct engagement of their points with caps placed over the switch .opera-ting plungers. These caps lare preferably of hard non-metallic material which will not dull the points of pins I, and yet which is impenetrable by the pins. As thesepins move downward through the buttons 2 after piercing them they will engage the caps 3.0 and .force them downward in opposition to the compression springs 3l, until switches 3 are `closed to energize the electric floor terminals 32 against which theoutlet block contacts 4 are pressed.

rIn. all such outlet blocks it is important to shroud the anchor points when the outlet block is .not in place over the outlet. In general such points may be either of the type Xed in the outlet block, which can be covered by an .element movable relative to the block, or .of the type themselves retractable into a cavity in the body .of the outlet block. Th'epoints I shown in Figure l are o t the latter type., being carried by a slide I0 which is separate from the outlet block but guided in the latter for movement toward and away from thev outlet, by fitting slidably within a chamber s tween the slide and the base.

in the outlet block body, formed by the wall II projecting upward from its base I2. Normally the slide IE) is urged away from the block base by a'c'ompressionspring @I3 encircling the points I and th'e electric contacts 4, and interposed be- Outward movement of the slide is `arrested in the broken line position of Figure 1 by a ilange I4 projecting inward beyond the inner surface of wall II, to engage the end of the slide,

While the points I are rigid with the slide Il), the contacts lare not. The contacts 4 are connected by strips 40 to wires 4I leading to th'e electric load. Such strips are sufliciently resilient so that when the outlet block is not in place the contacts will project somewhat below the bottom of the block. As it is pressed down, however, the strips will yield to hold the contacts 4 in rm engagement with terminals 32. Alth'ough the wires are shownv extending directly to the load they may instead be connected to con ventional jacks carried by the wall II into which a conventional plug can be inserted; Such ar rangement enables the outlet block itself to be disconnected from the load, although ordinarily such provision is not necessary because of the ease with which the outlet block itself may be removed from and replaced in proper position on the outlet. v

When the block is not in place on the outlet the action of spring I3 normally urging slide I0 into the broken line position of Figure 1, retracts the points I suii'iciently far so that their tips lie inwardly of the outer surface of the outlet block base I2. When it is desired to connect the load to the power source the operator presses the slide I downward with his thumb to compress spring I3, simultaneously projecting the points a vconsiderable distance beyond the block base. This operation may be performed either before or after the outlet block has been placed on the outlet plate 20, but preferably afterward. As the slide is moved downward, therefore, the points will be forced through the penetrable buttons 2 and eventually into engagement with the switch `caps 30. Unless the points are positioned to penetrate the buttons 2 the contacts 4 are not positioned properly for engagement with contacts 32; contrarwise, penetration of the. buttons 2 by points I assures correct positioning of th'e contacts. At least 4before the points I have entered the outlet sufficiently far to close switches 3 it is Adesirable that the block contacts 4 be in engagement with the floor electric terminals 32. Preferably the block ls placed on the base before projecting the points at all so that their lower ends will be braced against bending by the sides of the holes through base plate I2 as the pins are pushed into plugs 2. EvenI though the block should be pressed sidewise-during such operation the pins can not be bent. As soon as switches 3 are closed by the action described, current will flow from the power supply through such switches, terminals 32, and contacts 4 to wires 4I, and thence to the load.

If the thumb is now removed from the slide I0 it will be found that the parts will remain in the positions illustrated in'Figure l in solid lines. While the spring I3 will move the slide into the broken line position when the points I Aare not embedded in buttons 2, it is sufciently light so that the friction of the pins piercing buttons 2 to close switches 3 will prevent spring-induced movement of the slide after having been released by the operator. Thus thesllde will remainv'in its inner position,l to hold th'eblock in place and switches 3 closed, until the operator forcibly pulls the outlet block away from the outlet, by grasp# ing wall II, to withdraw the pinsy from the buttons. At that time of course, the spring will act immediately to retract the pins Iv within the outlet bl-ock. Similarly, if the outlet block is accidentally displaced, the points I are immediately and automatically retracted.

It is also to be noted that during this disconnecting operation the withdrawal of pins I from buttons 2 will enable springs 3| to return switches 3 to off position, thus deenergizing electric terminals 32 before the outlet block can be removed completely from the outlet. Also, as long as these pins project anyappreciable distance into the buttons the outlet block cannot be slid sidewise relative to the outlet to uncover the oor terminals, or even suiciently to move block contacts 4 laterally out of registry with them. Nevertheless slight tilting of the outlet block during withdrawal of the pins `from the buttons will not injure them because the slide I0 can tilt somewhat relative to the block wall II, and since the buttons 2 are of rubber or similar material, they will yield instead of bending the pins. Accurate registry of the pins with their apertures in the block base I2 is assured by forming slide I0 and block wall II of other than cylindrical shape. In Figure 2 the slide is shown to be of hexagonal cross section, and the block wall is of complemental hexagonV shape. Thus while the slide can reciprocate freely within the outlet block, and can tilt slightly, it cannot turn appreciably about an axis perpendicular to the block base I2.

In Figure l each spring 3l may be the spring usually incorporated in a normally open switch 3, or it may supplement such switch spring. If the switch springs are suiiiciently strong to return caps positively and quickly springs `3I may be omitted. If the action of switch 3 is stiff, a rather strong spring force will be required to insure its return to off position, and consequently the slender pins I might have diiculty in exerting sucient force to overcome the spring tension in closing the switch. v

Because of the stiffness inherent in the usual mechanical switch, especially of heavy duty type, it `may be preferable to use an outlet such as shown in Figure 3 with the outlet block of Figures 1 and 2. Energization of terminals 32 in this modified outlet is controlled by tilting mercury switches 33, the leads of which are connected by flexible connectors to the power source and to the floor terminals. These switches are pivoted in such fashion that they can be tilted between circuit open and closed positions with very little eiort. Following conventional practice, the glass tubes containing the mercury may be shifted lengthwise relative to their pivoted supporting bands to adjust their balance very delicately. They should be adjusted so that they will swing into the circuit closed position shown in Figure 3 when no external force is applied to them, but should be easily swingable into open circuit position by the application of a very slight force to them.

The switches may be tilted by engagement of the lower flange of a tube 34 with them, which tube is guided for vertical reciprocation by rod 35 extending centrally through the outlet. This tube is urged upward by a compression spring 36 reacting between the base of the outletbox and the tubes lower flange, but it lneed not be a strong spring, since the tube can be quite lightrequiring only a very small force to raise it and to tilt the mercury switches 33 into open circuit position. Conversely, therefore, tube-34 can be depressed by a light pressure of pins I on its upper flange to free switches 33 for tilting into circuit closed position. The upper ilange of this outlet should be made of hard, non-metallic material which will not injure nor be defaced bythe points I, and will not conduct electricity.

In view of the foregoing explanation as to the operation of the outlet block in conjunction with the outlet of Figure 1 the operation of this modied outlet will be readily apparent. When the outlet block is not in place upon the outlet spring 36 will maintain tube 34 in its upper position'so t that the mercury switches 4will be held in circuit open attitude. When the pins I are forced downward through the buttons 2 they will engage simultaneously the upper flange of tube 34 and slide it downwardly along rod 35 against the action of spring 36. As the lower flange of the tube is depressed the mercury switches will tilt of their own accord into circuit closed position, as indicated, to energize terminals 32. The tube will be held in this lower, circuit-completing position by the friction in buttons 2 of the pins I pressing the upper tube flange. Again it will be seen that the contacts 4 of the outlet block may be engaged with terminals 32 before the pins are moved to `close the switches 33. It will be evident, therefore, that an outlet block of the type shown in Figures 1 and 2 may be used interchangeably with the outlets of Figure l and Figure 3.

Instead of the position-maintaining pins I in the outlet block of Figures 1 and 2 having as their secondary function the closing of switches in the outlet, they themselves may constitute current conductors when applied to an outlet of the type shown in Figure 4. This outlet has no switch mechanism, but, on the other hand, it has no exposed floor terminals, such as 32 in Figures 1 and 3, which should be deenergized when exposed. In this form of outlet the penetrable buttons 2 in the floor plate 2U serve as covers for mercury cups 31 mounted on such plate, each constituting an electric terminal. When the pins I have pierced the buttons 2 they may be moved on downward into the mercury in these cups.

Particularly when the pins are withdrawn from the mercury in cups 31 of this continuously energized outlet, an electric arc is likely to occur, which may burn the sharp points more or less severely if they are connected directly to the load. It is preferable, therefore, to provide in the outlet block of Figures 1 and 2, when it is to be adapted for use with a continuously energized outlet of the type shown in Figure 4, switch mechanism which will disconnect both pins from wires 4I. An individual switch for each pin may include a switch point 42 carried by a strip 43 anchored to the pin slide Ill by its respective pin. This strip may be sufficiently resilient to move the switch point 42 slightly away from slide I0, but substantially less than the distance contacts 4 can be moved below the bottom of the block by resilient strips 40.

When this slide is in its outer position switch points 42 would be urged slightly away from the inner slide surface by the resilience of strips 43. As the slide is pressed downward with the outlet block in registry with the outlet of Figure 4, the pins I will be forced through the penetrable outlet buttons 2 into the mercury in cups 3l. Because the outlet has no terminals capable of registering with contacts 4, and switch points y112 up .tothat time are in open circuit position, no

regfmesz 7 .current eanrfiowfand consequently-inmarcingswifil sbe ."pro'duced: upon contact'iot' .ther 'ipinslwith the omereury. -'Byi continued'fnward movement of slidef'0,1:howeversidippingiEthe pnsf'fartherlrinto #the :rnercuryll in cupsiS'Lithei foutletiiblock switch rfpointscZ willfabe' :pressedlintorengagement 1 with fcomplementakswitchupointsMfmonnted.on'the strips 40 which connect contactsmavithfaviresilI. #Such engagement' of theswitohnpoints'will close lthe :circuitl :soffthatf'current will 'ow f from 1" the lmercury cuipslthroughf pins I fandeswitchpoints' 42 mandi -to the-fwiresi 4 I. viAlthoughf'these switch rpoints '.:will: bei 'closed isiinilarlyf-.wheni thisv outlet ublock isifappliedf to the -:outlets ofiFig-ures. 11.- or" 8 spins! I avillfinotebe shortedwbecauselof the-insulat- -ingich'ara'ctero buttonsfZE an'd capsi-"3lfE theou-tf-fletrirrfFigure lyior thefilangeY ofl tube 34" the' outletofFigure 3.

'.Corrverselywhen thefoutlet'fb'lockf'isi being reornoveclf-rorny the/outlet fof Figurei-'thefpressure sot the'.outlet 1 against contacts? llrwill-fbe relieveclas rsoonfas. the-3 lbase I 2 is llifted a short *distance :'Before the outlet ybloclrhas beerrfmovedsuiicientlyi tozwvithdraw the" ends -of pins? I I -fromf theflm'er- .gcurycin cufps3 1,.' spring? I a'remaining compressed -i'fan'dislidefIinitsflower position; t-he contacts 4 :.wi'llifbeemoved outward#- bythe xresilient deflection -zzof l the I'strips l4Ii suicientlyi-to ffwithdraw .switch points Mfrom Aswitch points42idespite 'the 'slight ,resilience QoL-:strips S43 "carrying f them. In this :manner:disconnectionofz thevload from .ipinsfA I is insured by separationnofcontact"points-42 Handi 44 :before "su'chizpins y'are I removedffcomplete'ly 1 'from '-.thermercuryin cups 31. #As withdrawalfofithe v:pins: is completedgtherfore; noarcing can' occur, rand'..they-willnotrbefburned.

#Structurali'features to 'preventuarcingf between :thet'conduotor Apinsaandthe mercury. in; cups `3'I duringftplacement a and -removall of 1an outlet block may; notfbe-fnecessary if. theloald oni thecircuitf is .-lightcorw ifitfcanr bedeenergized bynothen switch "for .fplug ,fa-nd ffjack fimechanism. iIn .fsuch f-event ibotlrtheooutletiand theoutlet blockrswitchesfmay -be=ornfri-tted` rFigure'A fillust'rates af'diierent type .of outlet rblock,` r.whose-"wall lvorrcase i I ymay@.betgener'al'ly semicylindrical in shape;constructedby'lan"insuflatingf'zmateri'al, 'ande the ibase I 2may fbe: remov- -ablyr'secnred to itiby=screws. *Insteadrloft'he pins .-I 6 being 'flon'g and r reciprocable relative i to "lit-he `v`blockwwails; as in the, outlet '.of"'Fi'gures"1 arid-2, 4they @may be t relatively :i-sliort, "being only A long "enough cipro-ject: fbeyon'cl theibase .1 I 2:' avfd'stance iapproxirnately equal 'to the Y maximum 'projectionuoffthevpins i I: beyondithewbase fin"`the:ou'tlet :bloclcfofsFigures ltandrz. fDual' pur-pose screws I 'I .mayfclampr t'hesefpins :inf position^ and'conriect to themvwiresd I leading-#either to j acks'fon the' out- -letfblock for engagementby ah conventional plug r12g-"as 'shownfomdirectlyr to' the load.

:Since the pins l IB .aref not retractable into' the outletib'lock whenf it is not 'infplace' over the outyrletfa'felarni.slfiellrcover I8, also' prferab-lyroff generally' .semicylindrical 'shape-asshown' -iniligure 5, may be pivoted on the case I4 by a hinge'IQ. About this' hinge the'cover may swing 'intothe lv broken line position in which* the points I'I'are completely shrouded within the= cylindrical-enclosure. Preferably a torsion Aspring is incor- 'porate'd in 'the hngesothatas soorras'the outlet block has" been/'lifted from the outlet the cover -w'ill be swung automatically `into point "protecting position. ISuch spring should not Vbe stiff.l enough to exert a' substantial tiltingf'for-ceupon-the outlet '.blockrproper when'i itspointslare "embedded '-in the i "8, outlets-so thatno-` appreciable tendency tofpry the "fil'tlet-block ff ythel-0titlete-vifill "betcreatd eA-normally;open-switch -45;-of the' same7 general 'type' as switohof Figure 1;may be Iincorporated .5 fm this outletl block-"between contaetsW-andwires Cil l insulating-material.

-4 I. y"'I'Yheswitch will: be fclose'd lvby'engagemet-'f its switchtaetuatmg l`PlungerlV B6 lwith outlet* plate 'zfasitheiiblo'ck is moved downward. y'Therrnove ment of the switch plunger'requiredtoblothis 'switch will?l be relatedI to theHprojection-*of "pins I6 into mercury.` cups? 3'Isoftl1at thefswitch lwillfnot l"be'closed by inward plunger movement un'tiif after the pinsf 1haverdippe`df= afsubstantialffdistance"into thev-meroury. f Conversely; asthe-ou"t1etv bloek' fis rzwitldrawnttof remove it; release'-ff pressure on :the @switchplunger'i4SlWill ie'ctopeningl of y"ft-he 'switch'fandf'consequent deenergization of 'thefload beforefthe -points'iIIi-rarey removed completely' from the mercury; =so`that2again= nolarcingi'betweenthe lponts'fand theflrneroury eanbcour. 4As theoover I8' swings into' the broken line' position of Figure afterfremovalfvo' theloutleti blockfrom the'outlet, fit'iwi'llpof course;` houseI the `switf'shplunger Las well as ypins I5.

Justias' the outletiblo'ck '-ifllu'strated-lirit'Figures 1 and i2f-fisiradapted forl interchangeable susewwith :zanyofvtheoutlets" o'f "Figures" 1,"f3= aride'4,.'sof-l the tblockfofsliguresi. 4 a'nd'f-mayl bef5 appliedtof either of 'the'.outlets' ofi/Figures. 1 anclB. l" In: such= event, '-of'coursefthei pins T I Iify no i-longer serve asf contductors" butinstead the lcontactsi 4: which'are" like thefoontacts'4inftheout1etfblock (v'Figun-zs,` 1'd and 2, simi1ar1y carry" the electriccur-rent. l-"Whenfan 'routlet"=blockfof eitherjthlig'ure' 1f -orFigurefl'type is placed on the outletofiiigurei thesecontacts, 1ofcourse,"carryno current.

f Pins! I"of".theffoutletf blockf-ffiligures 41and-5 iarecapab1epi2c1osingswit`ches3'on {i3-f the outlets Pfi Figures '1` and f respectively, #just "asf-do fpins Ii': oivtliet b'loek' f'figuresl 1.1ar1'd12. The -vpins Pmay factuate l the` 1 switchesI to i energize terminals :32 before contacts'tare` engagedwithi them; however; whereaswtlr the other' type gf outlet" block, ithefcontactsf, 4.2 are preferably engaged with" these terminals before the pinsl Iarez'reciprocatedwinto switch closing position by pressurefon'fslidef'l. circumstanceswoul'df-fbe 1in-imaterial, however, itf theuload'#werefdisconnected"from `wiresf-d I tby 'somef switch, 'or vplugfl".an'dwits jacksindependrentfvof the outlet and :outlet f'blo'ck.

vWifithrswfitch i 4 51 incorporated `in thelotletblock Tf I 5 in' thezmannershown howevenfdespite enerfg'izationf terminals 32farcingbetween"the con- "tactsf4- and fsuch?v terminals,= either ldu'ri'ng place- .ment or 'removal' 'f the'ou'tlet block, caril bejprefvented. TItiis f' merely necessary' 'that the 'strips .-lI'I fsupportingf contacts l 4 "flex sicien'tly "upon application *.fl thetoitIetE blo'ekl to` projeetf'these "contacts "beyond 'the-"outer jface -'of the 'outlet "block base I2 intofengagement'with terminals 32 before;plungermris' reciprocated far"enough by 'contact "wi-th' the outlet'to "close switch "45. "Conversely, Araisingfof the"outleti'block `will -en fable 'plungerlli to'moveyoutwardY'sufficientlyto vfopen-4 switchf-Ibfore contacts 4' areiifted'clear of terminals *32. "With this 'mechanism "also, thereforepallchanee of; arcing'fbetween" the block contacts 7"and "floor Zterminals vis vreliminated. "Moreovery-"the vtwo wires "4I 'cannoti'befshorte'd 'through themins VI or' I 6when"applied-toan `outlet offv'eitherthety'pe 'shown fin'Figurel or `"thatof Figure-3j beca-use thepimcontactwelements; 'the' caps "S0-'of the' formeroutl'et" and* the lflange 'f t tube "34 in the llatter 'o1'1`t1et, 1are "of While the various outlets and outlet blocks described above are all interchangeable, as discussed, none of these outlet blocks are designed for an outlet of the type shown in Figure 6 or in Figure 8, nor can either the outlet block of Figure 6 or that of Figure 8 lbe used with any of the above outlets. The principal reason for this lack of interchange-ability is that in the previous types two pins in the outlet block pierce two outlet buttons, so that the outlet block can assume only two different positions relative to the outlet. In the modifications of Figures 6 and 8, however, only a single pin pierces a button located centrally Iwithin an annular terminal ring or rings, so that the outlet block may assume any angular position desired relative to the outlet, yet it cannot be shifted across the outlet. On the other hand, additional penetrable areas may optionally be provided for engagement by other pins on the.

outlet block to hold it in some particular angular position relative to the outlet.

The simplest type of outlet for this embodiment of my invention, shown in Figure 6, includes a penetrable button made of rubber or similar material, heldin the iloor plate 5D. Beneath the button 5 is a mercury c11p5| carried by such plate, to which one wire of a power supply is connected, while the other supply wire is connected to a ring 52 embedded in the outlet plate in a position concentric with button 5. one of the terminals is in theform of an exposed ring 52, the power supply should be of the' grounded terminal type in which one of the wires is a neutral or ground wire, and that wire should be connected to such ring, `while the other is live.

The outlet block 6, made of insulating material, is cylindrical and hollow. Its diameter is somewhat greater than that of ring 52, so that it completely covers such ring when in place on the outlet. To its inner wall a band `is secured, carrying one, or preferably several;l contact feet 6I, which denne a circle conforming to ring 52. One connection 63 of the load circuit leads to band 50 and the other to the upper end of a pin l which is anchored rigidly in a .central bore of the outlet block. This pin is long enough so that, when piercing button 5, its end will dip well into the mercury in cup 5 A different arrangement has been usedin this outlet block to shroud the pin, although it might have been made retractable, as are t'he pins of the outlet block shown in Figures 1 and 2, or could have been shrouded by a clam shell type of cover, such yas shown in Figure 5. Instead a shield in the form of sleeve l0, encircling pin 1 and of a length somewhat greater than the projecting portion of thepin,y is guided for reciprocation in the central aperture of the outlet block. Whether such sleeve is of circular or other cross section is immaterial.'` The sleeve is urged by spring 1| toward a position in which most of it projects beyond the outlet block to shroud the projecting portion of the pin. The spring should not be strong enough to force the sleeve down in opposition to the friction of pin 1 in button 5 when the outlet block has been placed on the outlet. As the block is lifted from the floor plate 50, however, the spring will ,urge the sleeve outwardly tov follow up withdrawal of -the pin, so that when it has been removed from button 5 the sleeve will cover the pin completely. v

Manipulation of outlet block 6 tof place it upon the outlet merely requires locating it concen- Where trically lwith ring 52 and pressing it downward, l

thus forcing pin 1 through button 5 to enter Maese mercury cup 5|. The portion of the pin prjecting beyond the lower face of the outlet -blockl is long enough so that it will dip well into the mercury before feet 6| engage the ring 52, to.`

complete the circuit. Conversely, these feet will be moved away from ring 52 to break the circuit before the end of the pin 5 is withdrawn `from the mercury during the block removing operation.

Allpossibility of arcing between the point 'l andl the mercury is thus eliminated, despite the fact that no switch mechanism is included in either.`

'the outlet block or the outlet, and this will be true even though the load may not be otherwise l,

disconnected from the outlet block.

In Figure 8 neither the outlet block nor the outlet has an automatically operable switch, but a manual switch is incorporated in the outletfAv in `conjunction with an outlet block operated latch. As in the outlet of Figure 6, a penetrable button 5 is anchored in the floor plate 50 anda, ring 52, concentric with the button, is connected to rone terminal of the electric supply. In addi tion, however, a second ring 53, intermediate and concentric with button 5 and ring 52, isconnected` to the other wire of the electric supply. When used with an outlet of this type, therefore, the

pin of the outlet block does not serve as a cur-` f rent conductor.

Since both terminal rings 52 and 53 are ex- .posed when the outlet block is not in position on the outlet, the switch controlling ow of current to them should be in the off position while the outlet block is not in place on the outlet. switch 8 may break both wires of the circuit, al-

though interruption of the circuit through one may be sucient if the other is neutral. This switch is operated by pressure on a diaphragm 8U flush with the floor surface, depression of which will swing arm 8| downward about .pivot t2. This action reciprocates downward link 83,

the switch against movement into operative po. sition by accidental pressure on diaphragm when the outlet block is not on the outlet, therefore, itis merely necessary to latch one member in this linkage.

tip of the hook is engaged as a column between this block and the swinging end of lever 8 I. Pressure on diaphragm 80 tending to swing that arm is therefore transmitted through the tip of the hook to the block 88, which prevents the arm being swung downward into switch actuating` position by pressure on diaphragm 80. With the arm 8| thus latched, therefore, the entire switch actuating mechanism is rendered inoperativeto close switch 8. y

The latch hook may be reciprocated to place the Adownwardly offset end of arm 8| in registry with the hooks recess, so that it can be depressed to actuate the switch, by sliding the hook to the right in Figure 8 to the position of the parts r 4shown in Figure 9. This movement is eiected .l

by pressure of pin l against a platform 54 car- The Since the opposite end of this lever` agresse l.

ried by the end of a rod freciprocable in a support- 56# Normally this rod Ais heldI inits upper position bya leafspring 5engaging its lowerendf'andfsecured to the support. As,` the pin 'lisgpresseddownward by slide12,' however, the

platformll 4is depressed in opposition to' spring 51,jso;that-an iinclinedsurace adjacent to hook` Bren-gages it; or preferably acon-tactroller carried-'by such 'hock', to rWedge it to th'eright into the-ppsition of Figure 9, in..which the tip ofthe hookyh-asfmoved beyond the onset endof arm 8l.

Pressure upon diaphragm Bil-*willnow depress thisarinend into the hooks recess to move link 83-^and'lever Bllto closeswitch 8. When pressure upon platforrnfl 'is released byk Withdrawal offpin vl'from button 5,` andit is moved upward b-y spring 5l', a second "spring 89 'will' move hook 86back tothe left'into latchingy position, nin

whichthe endof the. hookis again interengaged betweenthe offset end ol? arm A8l Land the bed or pillow' block 88.

Wihen onlythe construction described is used diaphragm 88 'mustbe pressed continuously to kefepxswitch ElinV closed' position. Otherwise the return spring normally` provided in a switch of this ,type would `retur.n. its. plunger, lever 80., link" 83"andl'arml 8l to."oif""'position.44 To overcome the necessityofholding the diaphragm down, however, auxiliary latching mechanism, con,N trolled` bythe engagement Yof .pin 1 withplatforrn 545,* maywbel provided `in the forro. of detent 88",' This detent, reciprocable axially of the hook shank; is urged by a spring to project its end into the -hook recess. As the hook is wedgedtoward theofset end ofjarm 8l ,the detent will engage sucharm end and .be forced inward-to tension its springl Ii lthe diaphragmvilgis now depressed thejarrn end will be movedidownward below `detent 86 so that itiwill'belprojected byits springI i11tq 2;positon overlappingwsuch offset arm end, as shown in Figure k 9.v Although pressure .upon diaphragin .may be relieved, the switch spring cannot movearm lriupward because. itsoffset en dfyvillthus vbeheld depressed beneathdetent 86". This relationship ofthe parts, correspondinghtoJon position. of the switch, will be main-r tained aslongnas hookSis held to the right by pressure ofpinl'on platform 54.1

Whenpini is withdrawnfrom .button 5,'howeven, and since. projecting "movement of "detent 86"is-li.mited,'as shown in Figure 8, hook. 86" will be moved by spring 89, as platforn'1 5l"isr raised;- tothe -leftjsuiciently so that the projecting end of 'thadetent will' no longer overlie. the offset endjof arm 8i.' Enoughrspace will remainyhcwever, between the detent end and the hook tip to accommodate such offset arm endg. thusreleased; and it willberaisedout of the hooks recess Abythe switch spring acting throughlever 84Jandlinkg83, All the parts are thusreturnedto positions corresponding to-foffy positiong of-the switch',A and when the offset-end of hook Sli-has been lifted entirely out yof the hooks recess spring 89v will continue toA move the-hook' toftheilet` until its tip is again--interengaged -betweenthebase or pillow block 88 andthe-offsetV- arrnfend;V as irl-Figure f8. Thus-the switch -factuating mechanism-willbeV again 4locked in -off" 4position until the next time pin 'l is forceddown: ward throughbutton 5-to depressplatform 54.

The outlet lclockshcwn in Figure 3 is `generally-fY similar to that of Figure 6; but differs in certain* respects'. The -outerterminal ringy 52 is similaifl-yjfengaged" byfeet 6i projecting downward, froma-band fsecured `to the inner wall of the l2.L hollow block 5'.. An additional band 64 encircles' a central Icore of tlre;block, and -carries feet 65"for in the top of the outlet block such.r upward, movement is. `limited by engagement of aA stop collar 14"with .a shoulder on the slide in a position in which the pin l 'is retracted@ completely,E within the body. ofthe block.

In applying4 the outlet blocky 6" to the outlet-of Figure 8 the contact feet .6l 'and 65' are placed on the terminal rings.. 52 and: 53, respectivelyk which-"Willlocat'e pin 1"substantially above thev center .of button 5. As .slide 12 is pressedI downward pin'1 'will pierce button 5 .to engage the pin. end with. platform 51h` in, the..relati`onship of 'the parts, shown in ,Figure 8. Further. downward movementr .ofibutton YI2 "will now press. the pin.. and consequently, the. platforrm. downward to.

force hook 86 tothe rightintoth'e unlocked position of the parts .illustratedin Figure .9. If diaphragm 883s. now. depressed switch. 8. will be. yrnovedto on position to .energizethe terminal. rings 52 'and 53.and,j through contact feet 6l Sand..

I65 and bands. 60 .and 641;" the load. wiresb3..A As previous1y -explained,l detent 86"Wll hold arml to.- retain switch 8in closedposition vfor continuous..

energizationn of .the load.

If it is desiredlto operateswitch' lin-an intermittent .manner thefdetent .86', may-be removed,

from. th`e0ut1et"mechanism, but this is not necessary..v Intermittent'operation of :the switch byy manipulation. ofldiaphragm. Loan be. aio'rded without` ,removingnetent 865. ifpin 1 is raisedy slightly.. or pressed 4.downward only far. enough to move .hook.86,.tothe-right until'its..tip. clears the offsetr endofjarm I andnot fai-enough .to bring the., datent.,into.engagement..with .such .arm end..

or.intoa,posit'i'c'm` overlying-it... Theparts may be maintained in either thispositionor in deten-t engagedposition by .the friction ,of pin 1 in button 5 overcomngthe combinedffo'rce of spring. 13

actingupwa-rd'jon.sli'de;112; spring 51 acting, up-

ward onrod 55," and spring v89 'urgingliook'I 86 to,

the left. l

Additional pins 15;optionally.usable, may be received inrecesses in the wall'ofthe outlet block and heldin place by setscrews, so that their tips project a short distance lbeyond. the .outlet engaging ,face of the ontletlclocln'l These pinsvmay be pressed'jinto additional buttons, or a ring,58;.

of -penetralcle material," to preventl angular Amovement 'of -the `Aoutlet"*block'an'd'to anchor "itv more* securely against` inadvertent lateral displacement. Similar) additional 'pins may be inc-or'- .poratedinfthe-outlet block Groff Figures 6 and "l,A and portionsof permeableA material 58 mayv be included in the 'outletf'plate 50 A'of -Figure 6;

WhileY the outlet 'blocki incorporating the retractable pin" 11,1"is` shown yas appliedto the out; let of FigurefSBit could also be-usedl with-the out'- let'of'Figure. For this purpose .a metal washer 16fis placed-in 4the 'bottom' of the block bore 'and connected to band 164; so that the pin 41 will 'bein` circuitwith"such"band through washer 16;' spring 13 "seating .on fit; and the Apin:holdingiplate ene .gaged'b'ythe other "end'of 'spring "131 Wh'en'the.

outlet block 6 is placed on the outlet of Figure 6therefore, feet 6I will engage terminal ring I52, and feet 65 will be inoperative, engaging plate 50 of insulating material. Preferably slide 12 is .pressed downward and pin 1 forced through button 5 into the mercury in cup 5| before feet 6| contact ring 52`l Current will ow through the pin, spring 13, and ring 16 to -band 64, instead of through feet 65 to this band, to complete the circuit.

Alternatively, the outlet block 6 shown in Figure 6 may be used with the switch controlled outlet of Figure 8. For this purpose such block also has a second band 64 encircling a central core portion and carrying feet 65 located to register with terminal ring 53. The method of applying this outlet block to the outlet of Figure 8 will be obviousbeing accomplished in the same manner as placed on the outlet of Figure 6. Upon engagement of its pin 1 with platform 54 the latch mechanism will be actuated the same as when slide 12` is pressed downwar-d in the use of outlet block 6; as described in detail above. It is to be noted that no problem of arcing between the block contacts and outlet terminals is presented in placing either of these outlet blocks, since application of the block merely releases a latch and no current will now unt-il after switch diaphragm 80 has been depressed.

While the type of outlet shown in Figures 10,

11 and 12 is considerably different from the structures discussed above, the same principles are involved. In this mechanism a penetrable button 9 is mounted in an outlet plate 90. A

small locating aperture may extend through the center of such button to mark the proper location for insertion of the pin structure, but such aperture, when constricted, is too small for any appreciable amount of dirt to enter. The pin is of composite construction, including a metal core 9|, an insulating sleeve 92 shorter than the core and encircling it, and a metal sleeve 93 encircling the insulating sleeve. The core and the metal sleeve constitute conductor elements, and are connected to separate load wires 94. The lower ends of the core and sleeve 93 are spaced so that, when this composite pin structure is forced through button 9, the core will engage one supply wire terminal 95, whereas the outer metal sleeve is engaged by the other supply wire terminal 96. Insulating sleeve 92 should cover enough of the cores length so that it cannot engage both terminals simultaneously to short them. These terminals are supported by strips which are somewhat resilient, so that the terminals are urged into firm contact with the core and metal sleeve, respectively.

To protect the portion of the pin assembly above the floor and to serve as a handle a collar 91 of insulating material is formed around the pin assembly. Furthermore, as in the other modifications of my outlet, it is desirable to shield the pin structure when it is not engaged with the outlet. For this purpose a shell 98 is hinged upon a pivot 99 extending transversely of the pin structure, toswing from a position resting on the iloor and extending outward from collar 91, as shown in Figure 10, vto the pin shrouding position of Figure 11. The shield may be urged toward such shrouding position by a e torsion spring associated with pivot 99. When it is desired to swing the shield from its protecting position to that shown in Figure 10 so that the pin structure may be inserted intol the outlet button 9, upward pressure is applied to theI 14 handle extending laterally from the shield, which overcomes the spring force. The shield is held in such projecting position until the pin has been inserted into the outlet. The friction of the pin element with vthe button 9 will, of course, be

ample to overcome the slight tendency to raise collar 91 resulting from pressure of the shield against the iioor plate by the shield spring.

In Figures 13, 14 and 15 a different application of the principles of my invention is exhibited in conjunctionwith magnetic mechanism somewhat similar to that shown in my Patent No. 2,234,982, issued March 18, 1941. 'I'his type of outlet is particularly desirable for heavy duty use, such as for supplying power to machines of Various types in factories. All wiring may be embedded in the concrete floor F and run to the various junction boxes B, `in which this type of outlet may be instal-led. The outlet itself is carried by a floor plate |00 fastened to the junction box by screws. The switch mechanism for controlling energization of terminals |0| may be housed within a casing which can -be installed as a unit and Iwires W merely connected to the exterior terminals. l

The switch itself may be of the mercury type, incorporating a tube |03 containing a small amount of -mercury. One such tube would be sufficient if only one wire of the circuit were to be deenergized. If the outlet is connected to a source of current having both Wires live, however, ilow of current through both wires should` be interrupted. Two mercury tubes al 03 are illustrate-d, so that the outlet can be used for either system. These are mounted side by side in a cradle |04 supported by rod |05 to tilt between the circuit closed position of kFigure 13 and the open circuit position `of Figure 14.

In this type of outlet the switch may be closed l by a permanent magnet |06 housed Iwithin the outlet block |01. Preferably this magnet is of the horseshoe type, and rwhen the block is placed over the outlet in proper position the 4poles of the linagnet will be aligned respectively with extension pole pieces |08 embedded in the floor plate |00. When these pole pieces are magnetized by application of the outlet block they will attract and draw upwardly a Ibar armature |99 having a tubular shank ||0 pinned to the cradle |04 carrying the mercury tubes. To guide movement of the armature upward into proper registry with the pole pieces |08 a pin I l, threaded or other-.wise secure-d in iioor plate |90, 'has a knob on its lower end lprojecting downwardly into the tubular shank lI l0.

,Wires extending upward from the mercury switch tubes |03 are connected to terminals |0|. These are located for engagement by contacts ||r2 suspended by resilient folded strips I|v3 secured to the outlet block, so that when the outlet block is not in operative position the contacts project somewhat below its lower surface.

When the block is placed upon the outlet, therefore, these contacts engage the terminals lill, and the pull of magnet |06 draws the lower face of the outlet block down against the upper face of the floor plate so that the contacts engaging the terminals are pressed upward flush with the lower surface of the outlet block. This action stresses the folds of strips I3 so that a continuous resilient force pressing the contacts against the `terminals is produced. The magnet also, of course, by magnetizing extension pole pieces |08, moves armature |09 upward to close switches |03.

Conversely, when the outlet block is lifted the terial insert toy restrainmovement` of l said koutlet t block-parallel lto said floorf plate, `electrical conductors 'in-said outletv block' forA connection to ya load, a contact carried byA saidoutlet blockfor engagement with said terminal,y a switch housed within said outlet block and interposed between said contact and oneof'said electricalconductors, and means operable automatically by *application` of said outlet block to said floor plate to close said switch. l

6. An electric outlet comprising a-lfloor plate, exposed electric terminals carried by said .floor plat'e,`an outlet block, electric contacts carried by saidoutlet block for engagementlwith said' terminals'when the outlet block is placed on said flo'or plate, an insert` of penetrable material mounted in saidiloor plate", aholding pin vcarri'ed'by said outlet' blocl a slidewgu'iding said pin' `for` lengthwise reciprocation from jacavity in said block entirely 'shielding said pin vinto'a position piercing said insert when-the outlet 'block is-in place on the outlet to restrainlrelatlve lateral movement thereof, a switchAv adapted to energize one of said electric terminals, switch control means beneath said' penetrable material insert and engageable by said pin piercing said insert to condition said switch for enrgization of the terminal controlled thereby, and means carried by said Voutlet block operable to retract said pin into such block cavity when the outletblock is removed from the outlet. I l

7. An-,electric outlet comprising a floor plate, an electric terminal supported .from said floor plate, an insert of soft resilient materiaiinisaid floor plate, anoutlet block adapted to' bev positioned over said floor plate, a holding pin rigidly secured to said outlet block for penetrating said soft material insert to restrain movement of said outlet block parallel to said floor plate, an electric contact carried by said outlet block for engagement with said electric terminal, electrical conductors in said outlet block for connection to a load, a switch housed within said outlet block and interposed between said electric `contact and one of said electrical conductors, and means operable automatically by application of said outlet block to said floor plate to close said switch.

8. An electric outlet comprising a floor plate, an insert of soft resilient material in said oor plate, an electric terminal beneath said soit material insert, an outlet block adapted to be positioned over said floor plate, a holding pin carried by said outlet block for piercing said soft material insert to restrain lateral movement of said outlet block parallel to said oor plate and to engage said electric terminal beneath said insert, electrical conductors in said outlet block for connection to a load, a switch housed within said outlet block and interposed between said holding pin and one of said electrical conductors, and means operable automatically by application of said outlet block to said floor plate to close said switch after engagement of said holding pin with said terminal,

9. An electric outlet comprising a door plate, an insert of soit resilient material in said floor plate, an electric terminal beneath said soft material insert, an outlet block adapted to be positioned over said floor plate, a holding pin carried by said outlet block for piercing said soft material insert to restrain lateral movement of said outlet block parallel to said floor plate and to engage said electric terminal beneath said insert, and means carried by said outlet block oper- Y18 able automatically to shield said pin when the outlet block is removed from said iiocr plate.'

l 10'. Inanelectric outlet, an imperforate .fl-oor plate, an outlet blo-ck 'adapted to be operatively positioned over said floor plate, leads supported beneath the door plate,included n a power circuit, wires carried by the outlet block leading to a currentconsumer, disposed and arranged for corinaction,l'` through the floor plate, with said leads,I when theoutlet block is operatively positionedover the floor plate, and a holding pin carried by one of the outletblock or oor plate, and `a'r'esilient penetrable element carried by the other, 'the pin being normally retractedV when the two `are separated, but projecting in piercing position when 'the two are relatively operatively positioned, and penetrating said penetrable element to restrain lateral movement of said outlet block.

l1, Means for connecting an electric outlet to a load circuit, comprising an outlet block, terminals supported in said outlet block in position for application to 'external Y electric outlets, from which terminals extend leads in the load circuit; piercing points separate from said terminals, guided within" said outlet block for movement relative to su-ch block, resilient means reacting between said outlet block and saidpiercing points to 'retract the latter normally within the outlet block, and means operable in conjunction with theplacement of said voutlet block and its terminais' inoperative relationship to the external out.. Jets, to project said piercing points from .the outletblock, for penetration of `an externally located member, to prevent lateral displacement of said outlet v:block while `itsterminals are connected to the outlets.

12. Means for connecting an electric -outlet to a load circuit, comprising an outlet block, terminais supported in said outlet block in position for application to external electric outlets, from which terminals extend leads to the load circuit, piercing points separate from said terminals, guided within said outlet block for movement relative to such block, resilient means reacting between said outlet block and said piercing points to retract the latter normally within the outlet blo-ck, means movable relative to the outlet block to connect said terminals to such outlets, and means connected for operation by said latter means, and operatively connected to the piercing points, to project the latter during connection of the terminals to the outlet, for penetration of an externally located member, thereby to prevent lateral displacement of said outlet block While its terminals are connected to the outlets.

13. In combination with an electric outlet having current supply means for connection to a separable `load circuit, and a cover plate, and having an imperforate but penetrable area in its cover plate, an outlet block having within it load circuit energizing means supported for disposition in operative relationship to said current supply means by the placement of the outlet block upon said outlet cover plate, a piercing point separate from said circuit energizing means, mounted in and for movement relative to said outlet block in position to register with said imperforate penetrable area when the current supply means and the circuit energizing means are in correct relative operative disposition, means active upon said piercing point to retract it within the -outlet block, and means operable in conjunction with such placement of the outlet block and its circuit energizing means to project said piercing point, to penetrate the registering penetrable area, and

19 thereby to retain the outlet block in proper-operative disposition.

14. kIn combination with an electric outlet having a cover plate, and current supply means for connection to a separable load circuit, and having a penetrable but self-sealing area in its cover plate located in predetermined relationship to the current supply means, an outlet block having load circuit energizing means supported therein for disposition inoperative relationship to said current supply means, by the proper place- .ment of the outlet block upon said outlet, a piercing point mounted in said outlet block in position tov register with said penetrable area when the current supply means and the circuit energizing means are in correct relative operative disposition, means operatively associated With said .piercing point to enclose the same, butv disposable in nonenclosing position by proper placement of the outlet block and its circuit energizing means, and by movement of the piercing point towards and into said penetrable area, and means active t-o movev parts to point-enclosed position upon removal of said point from said penetrable area.

15. In combination with an electric outlet having a cover plate, and current supply means, in-

cluding a normally open switch means, for connection to a separable load circuit, and having a penetrable but self-sealing area in its cover plate located in predetermined relationship to the current supply means, and inregistry with the switch means, an outlet block having load circuit energizing means supported therein for disposition in operative relationship to said current supply means, by the proper placement of the outlet block upon said cover plate, a piercing point mounted in said outlet block in position to register with said penetrable area, and with the switch means therebeneath, when the current supply means and the circuit energizing means are in correct relative operative disposition, and upon penetration of said penetrable area to operatively engage said switch means, and means carried by said outlet block operable automatically to shield said pin when the outlet block .is removed from said outlet.

16. Means for connecting an electric outlet to a load circuit, comprising an outlet block, terminals supported thereby for connection toexternal circuits, a slender, sharp-pointed holding pin, means mounting sald'pin for projection from and for retraction into said outlet block in a position to penetrate a penetrable portionof an outlet engaged by the outlet block to restrain movement of the outlet block laterally of the outlet, vand means carried by said outlet block operable automatically to retract said pin into the outlet block when said outlet block is removed from the outlet.

DONALD S. ROSS.-v

REFERENCES CITED `The following references are of record in `the le of this patent:

Name Y Date 1,731,973 Fischer. Oct. 15, 1929 2,032,936 Staley June 3,1937

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