CA1161079A - Double disconnect waterproof electrical connector assembly for electrified vacuum hose for wet/dry vacuum cleaner - Google Patents

Abstract

DOUBLE DISCONNECT WATERPROOF ELECTRICAL
CONNECTOR ASSEMBLY FOR ELECTRIFIED VACUUM

HOSE FOR WET/DRY VACUUM CLEANER

ABSTRACT OF THE DISCLOSURE
A cylindrical molded plastic cuff at one end of a double flexible tube electrified vacuum hose for a wet/dry vacuum cleaner includes an integral molded plastic pocket bearing an elongated receptacle body of insulation material. The body includes two laterally spaced bores, counterbored from one end, which counterbores bear enlarged peripheral recesses inter-mediate of their ends, Cylindrical plungers sized to the counterbores and having a radially enlarged collar intermediate of their ends, in excess of the diameter of the counterbore but less than the peripheral recess, are slidably mounted therein with the collar positioned in the radial recess. A coil spring sized to the peripheral recess is compressed between the collar and one end of the radial recess to spring bias the plunger away from the bore. An O-ring seal whose outside diameter is approximately equal to that of the radial recess is positioned on the plunger to the side of the collar opposite that of the coil spring. The end of the plunger facing the bore carries a reduced diameter portion acting as a male contact which slidably fits into a small diameter axial hole within the facing end of a female contact having a base portion sealably carried within the bore of the receptacle body. A plug bears male contact prongs which project into female contacts formed within the end of the plunger opposite the compression spring.
The plug locks to the cuff when the plug male contact prongs mate with the female contacts of the plungers, and the plungers are forciably displaced against the bias of the springs to engage their male contact ends with the axial holes within the fixed female contacts to complete a two part electrical connection through the plug and between the electric motor driving a scrubber mechanism of a vacuum cleaner vacuum pick up head and an electrical source at the opposite end of the hose.

Description

~^ 1 ~6~(~79 DOUBLE DISCONNECT WATERPROOF ELECTRICAL
CONNECTOR ASSEMBLY FOR EJ,ECTRIFIED VACUUM
HOSE FOR WET/DRY VACUUM C_E~NER

FIELD OF THE INVENTION
This invention relates to hot water vacuum extraction machines, and more particularly to an improved electrified vacuum hose assembly for wet pick up and return of the dirty water from the surface being cleaned to a dirty water- acc~mulation tank to which the vacuum pickup head is attached by way of the vacuum hose.
BACXGROUND OF THE INVENTION
In recent years, hot water vacul~ e~traction machines have come into vo~ue for permitting the housewife to clean rugs and floor surfaces by spraying a very hot water onto the surfRce by means of a spray nozzle fixed to a vacuum pick up head. The resulting dirty water is returned to a dirty water accumulation tank borne by the machine remote from the head and connected thereto by a suction hose leading from the tank to the vacuum head. In an effort to improve the cleaning action at the point of li~uid spray applica-tion, such vacuum heads have employed electric motors driving a rotating ~rush or scrubber to aid ~n loosen-ing of the dirt. Whether the surface being cleaned is a rug, or a solid flooring, remova~ of the dirt is effected by entraining the water within the air stream flowing through the connecting vacuum hose under Yacuum pressure exerted at the dirty water accumula-tion tank.
Not only are there requirements to feed alternat-ing current voltage to the electric drive motor for the scrubber, but due`to the vacuum removal of dirty water through the vacuum hose, the electrical wires borne by the hose assembly must be maintained isolated 7~

-~rom the water returning to the tank. Otherwi~e, the ; water will short the electxical wires with resulting damage to the assembly, if not to the scrubber drive motor. In addition, it must be appreciated that in the utilization of the hot water vacuum extraction machines, such vacuum hose assemblies are subjected to considerable mechanical abuse, the hoses are dragge~
over the surface being cleaned, they contact objects of furni~ure during cleaning, and they may be stepped 0 on. This may not only impair their ability to carry the water during the vacuum return to the dirty water accumulation tank, but mechanical damage to the insu-lation surrounding the electrical wires, may, regard-less of their possible contact with water, lead to shorting ~etween the adjacent wires.
Such vacuum hose assemblies may be formed in a single or double concentric tube arrangement, with the tubes corrugated, tending to make them not only flexible but also permitting some expansion and con-traction of the hose assembly. Due to the utilization of tubular couplings at respective ends of the hose assembly fox coupling the hose assembly to th~ vacuum head at one end, and to the dirty water accumulation tank at the opposite end, electrical connection means must be attached to the lead wires. Male and female connectors electrically connect the leads borne by the hose assembly to the motor leads at the scrubber end of the vacuum hose and to the electrical supply means at the machine end. Where the hose assembly functions to return dirty wat~r, means must be provided for prevention of any water from getting to the leads.
Conventional single break connection and disconnection of the electrical leaks have in the past failed to insure against this possibility.
It is, therefore, a primary objec~ of the present invention to provide an improved electrified vacuum hose ~or a wet pick up machine, in which electrical disconnection of the electrical wires leading rom the machine proper to the scrubber motor of the pickup vacuum head, is assured,and wherein positive sealing of the electrical disconnect contacts is assured regardless of whether the electrical receptacle borne by the hose is in contact open or contact closed condition.
SUMMARY OF THE INVENTION
lo The present invention is directed to an improved electrified wet pick up vacuum hose assembly for a wet dry vacuum extraction machine, and specifically, for vacuum coupli~g of a vacuum pickup head to a dirty water accumulation tank, and wherein the vacuum head includes an electrically motor driven scrubbing assembly. The hose assembly is comprised of tubular couplings at opposite ends, and comprise concentric, inner and outer flexible tubes or hoses bearing at opposite ends, respectively tubular couplings. Elec-trical wires are carried between the flexible tubes for co~necting an electrical source at the water accumulation tank end of the hose to the electri~al motor at the vacuum head end. The invention i~
particularly directed to a plug and receptacle connec-tion assembly borne by the vacuum hose assembly at the vacuum head end thereof. The vacuum hose assembly comprises a cylindrical cuff bearing a pocket which mounts an elongated receptacle body to which i~
detachably coupled a plug having male contact prongs for insertion within receptacle body bores. The improvement resides in means forming a positive acting, double disconnect between the ends of the electrical leads leading to the receptacle and -th~
male contacts of the plug.
Preferably the receptacle body is formed of a molded insulative material bearing laterally spaced - bores, from one end of the body. The bores are counterbored and the counterbores bear circumferential ~ or peripheral recesses along a portion of their - length. An elonyated cylindrical plunger is slidably mounted within each counterbore and includes a radial collar intermediate of its ends having a diameter on the order of the diameter of the recess. A coil spring is mounted within the reces~ to one side of the collar and an O-ring seal is mounted to the opposite 1o side. The compression spring acts to noxmally shift the plunger axially such tha-t a male contact end is spaced from a female contact end of a fixed first contact extending through the bore and being held therein and being connected to an electrical lead wire borne between the vacuum hose. The plunger terminates on the side opposite the coil spring in a female contact which includes an axial bore for receiving the tip of a male contact prong portion borne by the plug.
The plungers form slid~ble contacts and the plug prongs form third contacts for the double disconnect connection assembly. Locking means borne by the rigid cuff envelopes the periphery of the electxical lead wire bearing the plug and abut a radially enlarged ; portion of the plug to lock the plug to the cuff with its male contact prongs projecting into the counter-bores and within the plunger female contact axial bores. This axially depresses the plungexs against the bias of the springs to the extent where engagement occurs between the male contact ends of the plungers and the axial bores within the female fixed contacts to the receptacle to complete a two break electrical connection between the plug and the wires of the vacuum hose, at that end of the hose assembly. The collar on the plunger functions along with one shoulder formed by the peripheral recess to insure sealing by the o-ring seal of the first and second :

contaets, interior of the receptac~e, regardless of whether the plunger i5 in closed contact or open contact position.
Thus, according to the present invention, there is provided an electrified wet pick up vacuum hose assembly for a vacuum coupling of a vacuum piek up head to a dirty water accumulatiDn tank for a wet/dry vacuum extraction machine. The vacuùm pick up head carries an electrical motor driven scrubber assembly for scrubbing of the surface being cleaned.adjacent the area of dirty water vacuum pick up. The hose assembly comp~ises concentric inner and outer flexible hoses connected at opposite ends to tubular eouplings and insulated electrical wires earried by the vacuum hose,assembly between the flexible hoses for connecting an electrical source at the water accumulation tank and the hose,assembly to the electrical motor at the vacuum head end. The improvement comprises a double disconnect electrieal connector mounted to the vacuum hose assembly.adjaeent the vacuum head end thereof. The double diseonneet conneetor includes a receptacle means bearing axially,slidable, sprlng biased first and second eontaets for effecting an initial, first disconnection and.a means for sealing the area of the initial, first diseonnection to the exterior of the hose assembly.

Sa ~i6~l~7 Figure 1 is a vertical sectional view, partially broken away, of one end of an electrified vacuum hose assembly for wet pick up and employing the double disconnect waterproof electrical connector as~embly, forming a.preferred embodiment of the prese~t inven-tion.
Figure 2 is an end view o~ the vacuum hose assembly illustrated in Figure 1 .
Figure 3 is a longitudinal se~tional view of the electrical connector assembly take~ about line 3-3 of Figure 1.
Figures 4a-4c inclusive are enlarged, sectional views showing the sequènce of making the electrical connection between th~ plug and receptacle elements of the elec~rical connector assembly of ~he present invention.
DESCRIPTION OF T~E PREFERRED EMBODIMENT
. Figure 1 shows one end of an electified vacuum hose assembly 10 for we~ pick up, forming one embodi-ment of the present invention. The hose assembly 10 i~ preferably part of a hot water vacuum extraction machine and forms a component thereof, functioning to make a vacuum connection between a dirty water accumu-lation tank (not shown) at the machine proper and a vacuum head (not shown) remote from ~he machine and connected to the machin via the hose assembly 10. In addition to forming a vacuum passa~e permitting return of dirty water after cleaning to the accumulation tank within the machine proper, the hose assembly 10 func~tions to permit electri~al current to be supplied to an electric motor (not shown) at the vacuum head and functioning to drive a scrubber assembly (not shown) ~. .

for scrubbing the surface being cleaned at the point of ~acuum application~
- The hose assembly 10 comprises concentric corrugated flexible or tubular hoses including an outer hose 12 and an inner hose 14 which are spaced somewhat to form an annular gap 16 therebetween.
Within this gap are longit~dinally borne, a pair of electrical leads or insulated wires 18 and 20 which 3 extend generally the len~th of the hose assembly 10 and which require some type of electrical connector assembly at opposite ends of the hose assembly.
Normally, conventional singIe break point connection male and female coupling means such as a male prong connector plug and a female connector receptacle bearing appropriate female type contacts make the electrical connections to wires borne by this type of hose assembly.
In order to effectively form a disconnectable tube coupling between the vacuum head and the hose assembly 10, there is required a rigid plastic tubular coupling indicated generally at 22 and to which the concentric hoses 12 and 14 must be coupled. In that regard, the inner smaller diameter flexible hose 14 is mounted directly to the coupling 22 with an end 14a in abutment with a radially enlarged collar 22a borne ~y that coupling. The end 14a of the inner hose 14 may be adhesively fi~ed to the periphery of the coupling tube 22, about reduced diameter portion 22b. Alterna-tively, some type of mechanical clamp may be employed to insure an air seal connection between hose 14 and coupling 22.
In addition to collar 22a, a second collar 22c is integrally provided to the coupling 22 forming a peripheral recess or gap 22d therebetween. Mounted within the gap 22d is an annular portion or flange 24a of a rigid plastic cylindrical cuff indicated ....

~6~(~7~

generally at 24, the cuf~ having a diameter in excess o~ the inner flexible -tube or hose 14 and having an outer diameter on the order of that of outer ho~e or flexible tube 12. The end 16a of the outer hose 16 is rigidly coupled by adhesive, welding or the like, to a mounting ring ~6. Ring 26 bears a peripheral recess 28 within its outer periphery, the diameter of the ring 26, at recess 28, ~eing generally equal to the inner diameter of cuf 24 with one end of the cuff being received therein and being rigidly coupled thereto by way of adhesive or the like. Thus, the ends of the inner and outer hoses 12 and 14 are seal-ably mounted to the coupling 22 and to cuff 24, respectively, the flange 24a permitting the cuff to rotate relative to coupling 2~ independent o~ the inner hose 14.
The present invention is directed to an elec-trical connector assembly indicated generally at 30 borne by the cuff 24 and wherein a waterproof double break electrical disconnect is effected between the wires or leads 18 and 20 leaking from -the vacuum hos~, and a pair of corresponding electrical leads indicated generally at 32 and 34, Figure 2, which are electri-cally insulated from each other and borne by an insu-lated conductor assembly 36, which terminates in a male plug indicated generally at 38. The male plug includes a pair of lateralIy spaced male contact prongs as at 40 and 42. The plug 38 is comprised of a p].ug body 44 formed of molded plastic, rubber or other insulative material which bears khe male contact prongs 40 and 42, and wherein internally the prongs are connected electrically to lead wires 32 and 34 borne by insulated conductor assembly 36.
The electrical connector assembly 30, in addition to plug 38j is comprised of an electrical receptacle indicated generally at 46, including a receptacle `7~

body 48 of gen~rally elongated rectangular ~orm, being : formed of an insulation material such as molded plastic, rubber or the like, and being specially mounted to cuff 24. In that respect, the cuff carries s a connector assembly housing, indicated generally at 50, which may be integrally molded with cuff 24 or may be separately molded and adhes.ively affixed to the periphery of cuff ~4. Housing 50 is generally U-shaped in transverse cross-section including a lo bottom wall 52, Figure 3, and opposed sidewalls 54, defining an elongated generally rectangular cavity or pocket 56. The front of the housing 50 includes an opening 58, that is, it is open at the end proximate to the coupling 22 and is closed off at end 50 remote ~rom the coupling tube 22, by a tapered end wall 60.
Further, the housing 50 includes a base portion or upper wall 62 terminating in an end wall or shoulder 6~ just rearward of opening 58. Correspond ingly, bottom wall 52 includes a transverse shoulder 66 diagonalIy opposite shoulder 64, the shoulders functioning as stops ~or the inserted receptacle body 48 and being sized to the length of that body so as to snugly receive ~he receptacle body 48 when the receptacle body 48 is inserted within opening 58 into pocket 56, during assembly of the connector components.
The cylindrical cuff 24 is provided with an elongated slot or opening 68 which opens to cavity 56 of the housing 50 through which the electrical leads or wires 18, 20 project for electrical connection to appropriate contacts borne by the receptacle body 48.
The receptacle body 48 is, as indicated pre-viously, of rectangular form having a top 70, a bottom 72, opposite sides 74 and 76, and a ~ront end 78 and a xear end 80. The rear end 80 of body 48 abu~s shoulder 66 when the upper edge of body front :;
end 78 abuts the shoulder or end 64 of base 62, after body insertion within the cavity 56 formed by hous-ing 50. A rectangular opening or hole 82 is formed within the rear end 80 of the receptacle body. The hole 82 extends laterally almost the full width of the receptacle body. Further, the body is provided with parallel, side by side, transversely aligned, bores às at 84, 86. Bore 84 is enlarged by a counterbore 88, bore 85 includes counterbore 90 to the side of bore 88 lo opposite that of hole 82. The counterbore 88 extends completely to the front end 78 of the receptacle body 48. The counterbore 88 includes an ~nlarged peripheral recess 92, b~tween the ends of the counter-bore, ~orming shoulders 94 and 96. hikewise, the counterbore 90 is provided with a peripheral recess 98 defining axially spaced shoulders 100 a~d 102, at opposite ends of this recess within counterbore 90.
As seen in Figure 3, bore 84 carries a female ; contact member indicated generally at 104, a counter-part female contact member 106 being provided within ; counterbore 88. Cooperating with the female contact members 104, 106 are resectively a solid cylindrical metal conductive plunger 108 within counter~ore 88, 3 and a similar plunger 110 within counterbore 90. The plungers are spring biased ~owards contact open posi-tion by means of coil springs 112, 114 respectively.
Additionally, within the peripheral recesses 92, 98, there are provided O-ring seals 116, 118 respectively for these plungers.
Referring to Figures ~A_4CI the make up of one-half of the electrical connector assembly may be readily appreciated particularly in view of the enlargement in scale of the elements illustrated therein. The female contact member 106, forming one contact of a series of three contacts for the connector assembly half, makes one of the double break 7~

disconnect by contact with spring biased plunger indicated generally at 110. Plunger 110 forms another contact. The plunyer in turn makes electrical contact with the male prony 40 of plug 38. The prong 40 forms a third contact for the connection process. In order to effect the electrical connection between lead wire 20 carried by the vacuum hose and the female contact member 106, the electrical insulation of the lead wire 20 is stripped back exposing the bare wire 1o conductor 20a which is preferably braized directly to the female contact member 106 after the end of the conductor 20a is inserted within an axially extending hole (not shown) within the center of the small diameter portion 106a of the female contact member 106. Further, the femaIe contact member 106 includes a second enlarged diameter portion 106b, thereby forming a shoulder on that contact member which abuts the end of counterbore 90 meeting bore 86.
The enlarged diameter portion 106b carries an axial hole or bore 106c which slidably receives a reduced diameter male contact or end llOa of plunger 110 and being siæed so as to form a tight but sliding fit when the plunger 110 is projected to the right, against the bias of coil spring 114. The coil spring 114 is sized such that one end abuts shoulder 102 of the peripheral recess 98 with.in the counterbore 90. Plunger 110, in addition to the reduced diameter portion llOa, includes a portion llOb of a diameter less than that of peripheral recess 98, which portion llOb joins the male contact llOa of -the plunger by an oblique or tapered plunger portion llOc. The plunger 110 is further provided with a radial enlargement or collax ll~d of a diameter in excess of that of plunger portion llOb but less than that of the annular recess 98 within which the collar llOd is positioned.
To the left of the co~lar llOd, is a further reduced q)7~

diameter portion llOe. Plunger 110 terminates on the right in a slightly enlaxged diameter portion llOf.
Portion 110, collar llOd, and reduced diameter por-tion llOe defines a peripheral groove 120 on the plunger within which is positioned, O-ring se~
having an internal diameter less than that of the plunger portion llOf and an ou-ter diameter equal to or slightly greater than the diameter of the annular recess 98 within the receptacle body counterbore 98.
lo The coil spring 114 has its end opposite shoulder 102 bearing on a radial face of collar llOd, forcing the plunger llO to the left as shown in Figure 4a. This causes the O-ring seal to be com~
pressed between the collar llOd and shoulder lOO
lS forming a very effective seal to seal the receptable cavity bearing the plunger male contact llOa and the female contact lO6. Further, preferably, the axial hole 82 within the receptacle body 48 is filled with a potting compound or other material 124 to not only seal off the electrical connection between the leads 18 and 20 and their female contact me~bers 104, 106, but also to seal off the chambers defined b~
counterbores 84 and 86 and ~he peripheral recesses 96, 98, within which is initially achieved the electrical disconnection between -the male contacts integral with the plunger and the female contacts with which they mate. The end face of the plunger opening to the exterior of the receptacle body, as at llOh fox plunger 110, bears an axial hole as at 126 of rela-tively shallow depth and is of a coniguration corresponding to the rounded tip 42a of the plug male prong 42. The same occurs for the other half of the connector assembly. The axial holes closely receive the ends of the prongs during the double disconnect, electrical çonnection achieved between prongs 40, 42 of plug 38, plungers 108, llO and the corresponding female contac~ members 104, 106, respectively.

For the o-ther half of the assembly, an identical assembly of parts are provided to achieve a double break electrical connection between prong 42, plunger 108 and female contact member 104, the action occurring simultaneously and in a corresponding manner to that illustrated in Figures 4a-4c inclusive. To achieve this action, the housing 50 is further pro-vided with an integral lscking member or stop indi~
cated generally at 128. Stop 129 comprises an integral depending projection with a tapered face 13~, and bears an arcuate recess 13~ forming opposed bi~ur-cated fingers 134. The tapered or inclined wall 130 facilitates sliding of the male plug 38 into the position shown in Figures 1, 3 and 4c, where right angle end face 38a of the male plug 38 abuts the rear ends 136a of ingers 136 formed by bifurcating the stop member 128. In achieving this action, the male prong is moved in the direction of the arrows, Fig-ures 4a, 4b, causing the rounded tips of the prongs 40, 42, to engage within the shallow recesses within the plungers 10~, 110 respectively. This action displaces the plungers rearwardly against the bias of the co.il springs moving the o-ring seals away from the shoulders and forcing the male contacts of the plungers to engage the female contact members by projecting within the a~ial bores provided within the ends thereof. Connection is achieved, while sealing is assuredi since the o-rings must move with the plungers due to their being carried within the recess formed by the reduced diameter portion llOe of the plunger. A double seal is effected since *he O-ring performs the function of the primary seal and the potting compound 124 functions to secondarily seal off the receptacle body 48 at the point where the lead wires 19 and 20 are connected to the female con-tacts 104, 106 carried by the receptacle.

During disconnect, the opposite sequence occurs, that is, Figure 4c back to Figure 4a. ~s may be appreciated, there is a double electrical disconnect or break, the first occurring as the male contacts move out of the bores o~ the female contacts Figure 4b, and the second as the prongs move away ~rom the female contact portions of the plungers. The plunger movement actually ollows the movement of the male contacts or prongs of plug 38, insuring initial lo or early first electrical disconnect in the sealed cavity defined by bores and counterbores and the peripheral recesses within the receptacle body 48, sealed of ~rom the exterior by way of the O-ring seals 116, 118.
It is important that the double break occur during electrical disconnection, and that the initial disconnection be effected in a sealed space achieved by effecting disconnect between the plungers and the female contacts borne by the receptacle body. How~
2Q ever, it makes no di~ference if the plunger carries the female contact and the male contac-ts are fixed to the plunger body, that is, the opposite to that illustrated in the drawing.
While the in~ention has been particularly shown and described with reference to a pre~erred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing ~rom the spirit and scope o~ the invention.

Claims (3)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an electrified wet pick up vacuum hose assembly for vacuum coupling of a vacuum pick up head to a dirty water accumulation tank for a wet/dry vacuum extraction machine, and wherein the vacuum pick up head carries an electrical motor driven scrubber assembly for scrubbing of the surface being cleaned adjacent the area of dirty water vacuum pick up, said hose assembly being comprised of concentric inner and outer flexible hoses connected at opposite ends to tubular couplings, insulated electrical wires carried by the vacuum hose assembly between the flexible hoses for connecting an electrical source at the water accumulation tank and the hose assembly to the elec-trical motor at the vacuum head end, the improvement comprising:
a double disconnect electrical connector mounted to the vacuum hose assembly adjacent the vacuum head end thereof, said double disconnect connector including receptacle means bearing axially slidable, spring biased first and second contacts for effecting an initial, first disconnection and means for sealing the area of said initial, first disconnec-tion to the exterior of the hose assembly.

2. The improved electrified wet pick up vacuum hose assembly as claimed in claim 1, wherein the end of said vacuum hose assembly comprises a cylindrical cuff mounted to said tubular coupling, said cylindri-cal cuff including an elongated pocket, an elongated receptacle body mounted within said pocket and being formed of insulative material, said receptacle body including laterally spaced longitudinally extending bores from one end thereof, said bores being counter-bored over a portion of their length and bearing in turn peripheral, circumferential recesses, an elongated cylindrical plunger being slidably mounted within each counterbore, each plunger including a radial collar intermediate of its ends, said collar having a diameter on the order of the diameter of the periph-eral recess and being positioned therein, a coil spring being mounted within the recess to one side of the collar and abutting the collar at one end and a shoulder formed between the recess and the counterbore at the opposite end thereof, the compression springs acting to normally shift the plungers axially towards one end of the recess, means for supporting an O-ring on said plunger to the opposite side of said collar from said coil spring for sealing off the cavity formed by the recess, a fixed first contact within said bore and having a portion opening to the interior of the cavity and facing the end of said plunger bearing said collar and being engageable therewith to form an initial sealed disconnect first break for an electric circuit through said hose assembly supported electrical leads.

3. The improved electrified wet pick up vacuum hose assembly as claimed in claim 2, further compris-ing locking means borne by said rigid cuff and wherein said connector assembly further comprises a detachable plug bearing a pair of male contact prongs projecting outwardly therefrom at one end thereof and being connected to electrical wires at their other ends, said plug being detachably coupled to said receptacle and being frictionally held to said receptacle by said locking means which envelope the periphery of the electrical leads coupled to said plug prongs with said locking means abutting a radially enlarged portion of said plug and with said male contact prongs projecting into respective counterbores of said receptacle body! and wherein the end of each plunger within said counterbore facing said plug bearing axial recesses corresponding in configuration and size to the ends of said male contact prongs borne by said plug such that a two break connection is initially made by first inserting said prongs into said counterbore, causing the tips of said prongs to engage the recess within the end of each plunger and subsequently each plunger is forced to move axially against the bias of the compression springs to the extent that said first and second contacts engage to complete the electrical circuit between the leads borne by said plug and the leads extending from between the flexible hoses and connected to said fixed contacts.