COMBINED ASSEMBLER AND CONNECTOR PLUG AT ITS REAR

This invention relates generally to electric cigar lighters of the type commonly employed in automotive or recreation vehicles, and more particularly to specialized electrical connector constructions for energizing such lighters.

The present invention relates more particularly to improvements in the cigar lighter receptacle construc¬ tion illustrated and described in assignee's expired U. S. Patent No. 3,532,849 dated October 6, 1970, issued to L. Horwitt, and entitled BIMETAL SHUNT FOR ELECTRIC CIGAR LIGHTER. Reference is specifically made to the embodiment of Fig. 4, and that of Fig. 5 of this patent.

The following patents are hereby made of record and are believed to constitute a sampling of existing prior art in the particular field to which the present inven¬ tion relates:

U. S. Patents Nos. :

2,224,034 2,248,402 2,256,876

2,258,989 2,262,484 3,012,120 3,424,414 3,462,721 3,818,179

3,863,047 3,870,857 3,892,944

3,904,848 4,498,726 4,580,856

4,650,962 4,669,185 4,713,017

4,713,733 5,044,993 5,116,233

U. S. Patent No. 3,532,849, Figs. 4 and 5, disclos¬ es cigar lighter constructions incorporating bimetal shunts disposed in adapter shells (22, 22') mounted at the rear of a lighter socket. In such constructions, controlled flexing of the bimetal occurs unless an over¬ heat condition arises in the socket, such as that result¬ ing from a short circuit in either the socket or the removable ignitor unit. In the event of malfunction, the bimetal flexes sufficiently to electrically contact the inner surface of the shell, thereby shorting the hot lead to ground, and purposely blowing an in-line fuse so as to minimize the possibility of a fire.

The concept of the bimetal shunt circuit in a cigar lighter socket has been widely accepted since the advent of this patent, and devices embodying the basic concept thereof have, as a result, enjoyed great commercial suc¬ cess over the years, having been utilized in millions of automotive vehicles and spanning a period of more than two decades. Particular reference is made to the following three patents:

1. U. S. Patent No. 3,012,120 discloses an in-line bimetal circuit breaker for installation at the rear of a cigar lighter socket. As shown, only the "hot" electri- cal circuit is controlled; the ground side of the cir¬ cuit remains intact after the breaker opens. As opposed to Patent No. 3,532,849 discussed above, this patented con-

struction did not "shunt" the hot side of the circuit during an overheat condition. Instead, it effectively "interrupted" the circuit, as in the case of a fuse or circuit breaker, and once such an interruption occurred, the device was intended to be removed and discarded, and a substitute unit installed. The device retrofitted to existing cigar lighter base constructions, as stated in col. 3, line 25 of the patent.

2. U. S. Patent No. 4,498,726 illustrates and describes a connector for a cigar lighter socket of the kind having a bimetal safety shunt similar to that of Patent No. '849 identified above. The current carrying leads for both the hot and ground sides of the cigar lighter circuit are embedded in a molded plastic or rub- ber plug, and the plug is adapted to be pushed onto the central terminal stud of the base, and in addition, to make electrical contact with a screw shell carried by the base. In this construction, the bimetal shunt is a part of the cigar lighter socket per se. 3. U. S. Patent No. 3,462,721 illustrates and describes a circuit breaker for a cigar lighter, in the form of a capsule-like enclosure disposed at the rear of the lighter socket, and containing a bimetallic circuit- breaker type element. The breaker element is adapted to open the hot side of the circuit in the event of over¬ heating of the socket or plug as a consequence of mal¬ function. Provision is made for insertion of an elongate rod through the socket from the front, to access the

interior of the enclosure and enable the breaker mech¬ anism to be re-set, following actuation.

Referring now to others of the patents listed above, three show another form of cigar lighter which has been in widespread use in this country, for at least 15 years. In particular, U. S. Patents Nos. 3,870,857; 3,892,944; and 3,904,848 contain generally similar disclosures which describe cigar lighter structures that are especially adapted for manufacture and assembly by means of auto- mated equipment. At the time of issuance of these pat¬ ents, the disclosed lighters were referred to by the assignee corporation, as "New Generation Lighters", because of the advances that had been made with respect to economy, ease of assembly, low failure rate, and the ability to mass produce them in large quantities.

U. S. Patent No. 5,116,233 discloses a cigar light¬ er construction utilizing a modified form of bimetal shunt, somewhat similar to that of Patent No. '849 noted above. In this patented design, the bimetal shunt is disposed inside the lighter socket, and is indicated at (17). Overheating of the pull-out igniting unit (not shown) , or of the socket itself results in the bimetal contacting the inner surface of the metal socket wall (18) , in turn causing an in-line fuse (not shown) to blow and thus minimize potential fire hazard.

The remaining patents mostly deal either with bimetal circuit controllers, or else with various terminal configurations associated with known cigar lighters and which were designed to facilitate making electrical connection thereto. These are briefly discussed hereinbelow, in chronological order.

Patent No. 2,224,034 shows an early lighter design employing a bimetal element that is utilized solely as a releasable, non-current carrying clip which is engaged by a heating element cup when the lighter is actuated. One side of the electrical circuit was established through the metal socket of the lighter, while the hot side (stud 28, Fig. 1) accepted a crimp-type lug con¬ nected to an electrical lead of the wiring harness (not shown) of the vehicle's electrical system.

U. S. Patent No. 2,248,402 illustrates another type of lighter construction in which a bimetal carried in the socket of the device is employed to release a latch that holds the ignitor plug as it is being energized. As in the patent of the previous paragraph, the bimetal itself is electrically out of the circuit, and merely functions to sense that a predetermined heat level has been attained by the heating element of the ignitor plug. U. S. Patent No. 2,256,876 illustrates a cigar lighter construction employing two bimetals, one to con¬ trol latching and release of a spring-biased ignitor plug, and a second bimetal which, in the embodiment of Fig. 1, presses against the first with variable pressure

depending upon the ambient temperature prevailing at any particular time. The objective is to minimize undesirable fluctuations in the operation of the first bimetal latch which would otherwise result from changes in its "starting" position due to ambient temperature varia¬ tions. This patent was cited against U. S. Patent No. 3,863,047, discussed below.

U. S. Patent No. 2,258,989 illustrates a temperature sensor plug of especially compact design and which in- corporates a bimetal member having multiple reverse bends to the end that changes in temperature cause deflection of the various branches of the bimetal in a manner where¬ in they are cumulative, in order to obtain maximum deflec¬ tion and sensitivity over the range of temperatures being monitored. This patent was cited against Patent No.

5,116,233 discussed above and which related directly to a bimetal shunt for a cigar lighter.

U. S. Patent No. 2,262,484 illustrates an automatic cigar lighter having a disk-like bimetallic element which is disposed exteriorly of the socket of the lighter, and which is mechanically flexed by insertion of the ignitor plug, to close external switch contacts. Upon experienc¬ ing heat from the heating coil of the ignitor plug, the bimetallic element reverses its curvature and opens the contacts. The bimetallic element itself is separate from the current carrying part of the circuit, and as a result carries no current per se.

U. S. Patent No. 3,424,414 illustrates a known cigar lighter receptacle of a type which employed the usual bimetallic latching fingers for engagement with a heat¬ ing element cup of an ignitor plug. This patent was cited against Patent No. 3,532,849 noted above.

U. S. Patent No. 3,818,179 discloses a cigar light¬ er of a type having conventional internal bimetallic fingers which engage a heating element cup of an ignitor plug, and the socket of which has a rearwardly extend- ing, generally cylindrical terminal post (27) for con¬ nection to a source of power, not shown. The receptacle configuration adapted to mate with this post is sim¬ ilarly not shown.

U. S. Patent No. 3,863,047 describes a cigar light- er having incorporated therein a bimetal shunt adapted to respond to overheating within the socket by shifting against a plate connected to the hot terminal, to blow a fuse and minimize potential fire hazard. In one embodi¬ ment, the bimetal is carried by the ground side of the cigar lighter circuit, and is arranged to bridge the hot side of the circuit upon experiencing overheating. In a second embodiment, the bimetal is carried by the hot terminal, and is arranged to contact the inner surface of the cigar lighter socket upon experiencing overheat- ing therein.

U. S. Patent No. 4,580,856 discloses a composite clamp shell for a cigar lighter, constituted of two pieces and including an integral spade lug type terminal

for connection to the ground side of an electric cir¬ cuit, as by means of a grounding push-on type recepta¬ cle. Patent No. 4,669,185 contains a similar disclosure, having been a Divisional Application based on the Application which matured into Patent No. 4,580,856.

U. S. Patent No. 4,713,017 illustrates and describes an electrical power outlet having a configuration some¬ what similar to that of an electric cigar lighter socket. The rear of the socket contains two flat electrical ter- minals for connection to an electrical circuit.

U. S. Patent No. 4,713,733 discloses a cigar light¬ er having a socket with two rearwardly-extending spade lugs for connection to an electrical receptacle (not shown) . U. S. Patent No. 5,044,993 illustrates a power out¬ let construction comprising a socket formation having rearwardly extending contacts in the form of flat ter¬ minals, one of which is integral with the socket forma¬ tion of the cigar lighter, having been stamped out there- from. The resulting end portion of the one terminal is folded back upon itself, to form a contact terminal com¬ prising a double thickness of metal, for improved strength.

While the devices disclosed in the patents noted above have in some circumstances met with commercial success, there is a continuous need to reduce overall manufacturing costs, including steps toward either min¬ imizing or eliminating manual labor. In many of the pat-

ented structures, this objective of cost has not been adequately addressed.

Currently there exists a pronounced trend toward use of plastics in the automotive field, especially in the passenger compartment; accordingly, special atten¬ tion must be given to potential sources of heat and/or fire. In some of the patented cigar lighter construc¬ tions employing a bimetal shunt, the bimetal was exposed at the rear of the socket. When overheating occurred, resulting in actuation of the bimetal shunt, arcing at the point of contact between the bimetal and its sur¬ rounding grounded conductor was considered somewhat of an electrical hazard.

Also, most prior lighter designs utilized specially configured connectors for energizing the cigar lighter through the socket. Until recently, relatively little attention was given toward standardization of the socket structures and their terminals, and as a consequence, a multiplicity of divergent socket designs have been devised and utilized over the years.

The above disadvantages and drawbacks of prior cigar lighters are largely obviated by the present in¬ vention which provides a combined assembler and connector plug for a cigar lighter of the type having a socket shell, comprising, in combination a hollow molded plas¬ tic plug body having a recess adapted to receive a female electrical connector receptacle of the type pro¬ vided with at least one slit in which a metal contact

part is disposed, said plug body having a wall portion defining a wall of said recess, a contact prong member disposed in the recess of the plug body and adapted to be received in the slit of said receptacle, said prong member having a base portion which is molded in the plug body and which has an accessible opening adapted to receive the shank of a fastener stud carried by a cigar lighter shell, to secure the plug body to said shell. The invention further provides an electric cigar lighter for vehicles comprising, in combination a metal receptacle shell adapted to receive a lighter plug, bimetallic clip means insulatedly carried in said shell and adapted to engage and energize a lighter plug insert¬ ed therein, a fastener stud which carries said clip means, said stud having a shank projecting from the rear of the receptacle shell, a combined assembler and connec¬ tor plug comprising a hollow molded plastic plug body having a recess adapted to receive a female electrical connector receptacle of the type provided with at least one slit in which a metal contact part is disposed, said plug body having a wall portion defining a wall of said recess and said assembler and connector plug further comprising a contact prong member disposed in the recess of the plug body and adapted to be received in the slit of said connector receptacle, said prong member having a base portion which is molded in the plug body and which has an opening which receives the shank of said fastener stud to secure the plug body to said receptacle shell.

The invention still further provides a combined assembler and connector plug for securement to a cigar lighter receptacle shell, comprising, in combination a hollow molded plastic plug body having a recess adapted to receive a female electrical connector receptacle of the type provided with at least one opening in which a metal contact part is disposed, said plug body having a wall portion defining a wall of said recess, a contact prong member disposed in the recess of the plug body and adapted to be received in the opening of said receptacle, said prong member having a base portion carried by the plug body, said plug body having a relief, and a bimetal shunt disposed in said relief and electrically connected with said contact prong member, said relief facing the cigar lighter shell when the plug body is attached there¬ to, said bimetal shunt having a contactor portion which, when the bimetal shunt experiences heat, shifts toward the said shell so as to come into electrical contact therewith for the purpose of actuating a protective, circuit-opening fuse.

The invention also provides an electric cigar light¬ er for vehicles comprising, in combination a metal recep¬ tacle shell adapted to receive a lighter plug, bimetal¬ lic clip means insulatedly carried in said shell and adapted to engage and energize a lighter plug inserted therein, a fastener stud which carries said clip means, said stud having a shank projecting from the rear of the receptacle shell, a combined assembler and connector

plug attached to the rear of the shell, said plug com¬ prising a molded plastic plug body having a pair of con¬ tact prong members carried by said plug body, one of said prong members being electrically connected to said fastener stud, a spring washer carried at the rear of the receptacle shell and sandwiched between the shell and the plug body, the other one of said contact prong members having a base that is exposed at the surface of the plug body, said base being resiliently engaged by the spring washer so as to effect an electrical connec¬ tion to the socket, through the washer.

The invention still further provides an electric cigar lighter socket comprising, in combination a metal receptacle shell adapted to receive a cigar lighter ignitor plug, a glow ring assemblage carried on said receptacle shell, said assemblage including a translucent ring and a source of light for illuminating said ring, a molded plastic plug body carried at the rear of the shell, a contact prong member carried by said plastic plug body, for connection with an electrical connector receptacle, said prong member having a base portion which is imbedded in the plug body, means providing an external electrical contact on said plug body, electric¬ ally connected with said prong member, means providing a cooperable electrical contact on said glow ring assem¬ blage, said cooperable electrical contact being connect¬ ed to energize said source of light, one of said electri¬ cal contacts being annular, so as to electrically engage

the other electrical contact regardless of the angular disposition of the glow ring assemblage with respect to the plug body.

Finally, the invention also provides an electric socket for use in vehicles, comprising in combination a metal receptacle shell, a molded plastic plug body car¬ ried at the rear of the shell, said plug body having a plurality of electrical terminals for connection to a cooperable connector receptacle plug, one of said ter i- nals being electrically connected to said shell, said shell containing an insulated electrical contact, and a second one of said terminals being electrically connect¬ ed to said insulated electrical contact, an external annular contact on said plastic plug body, said annular contact being connected to a third one of said electri¬ cal terminals, said external annular contact being adapt¬ ed for connection to a load, means providing an electri¬ cal connection between said external annular contact and the load, which connection-providing means engages the annular contact regardless of the angular disposition of the load with respect to the plug body.

Other features and advantages will hereinafter appear.

In order that the invention may be more readily understood, reference will now be made to the accompany¬ ing drawings, in which:

Figure 1 is an axial sectional view of the cigar lighter socket member and assembler and connector plug

therefor .

Fig. 2 is an axial sectional view of the construc¬ tion of Fig. 1, taken in a plane that is displaced 90 degrees from that of the section of Fig. 1. Fig. 3 is a rear elevation of the cigar lighter socket member and assembler and connector plug of Figs. 1 and 2.

Fig. 4 is a side elevation of the cigar lighter socket member and assembler and connector plug of Figs. 1 and 2.

Fig. 5 is a side elevation of the fastener stud utilized in the cigar lighter socket member and assembler and connector plug of Figs. 1-4.

Fig. 6 is a perspective view of a combined electric terminal prong and electrical contact utilized in the cigar lighter of Figs. 1-4.

Fig. 7 is a perspective view of another terminal prong utilized in the cigar lighter of Figs. 1-4.

Fig. 8 is a perspective view of still another ter- minal prong utilized in the cigar lighter of Figs. 1-4. Fig. 9 is a perspective view of a bimetallic shunt utilized in the cigar lighter of Figs. 1-4.

Fig. 10 is a top plan view of a resilient, bowed spring washer utilized in the cigar lighter of Figs. 1- 4, and

Fig. 11 is a side elevation of the washer of Fig. 10.

Referring first to Figs. 1-3, there is illustrated a cigar lighter receptacle generally designated by the numeral 10, comprising a socket member 12 in the form of a metal receptacle or socket shell which is adapted to receive an ignitor plug (not shown) of an electric cigar lighter. Such lighters are well known, being of the type conventionally utilized in motor vehicles.

In accordance with the present disclosure, at the rear of the shell 12 there is provided a combined assem- bier and connector plug assemblage 14 constituted of molded plastic and metallic parts which perform multiple functions whereby appreciable cost reductions are realized, Basically the plug assemblage 14 comprises a molded plas¬ tic plug body 15 having a side wall 56 and a transverse bottom wall 17, said body 15 being formed to have a cup- shaped recess 16 in which there are multiple projecting spade-type terminals or lugs 18, 20 and 22 all to be described in further detail below.

Referring first to the shell 12, this is telescopic- ally received in a transparent or translucent glow ring 24, Fig. 1, after which these parts are intended to be pressed into a mounting hole of a supporting panel (not shown) such as a motor vehicle dashboard, and permanent¬ ly retained therein in a known manner per se. The glow ring 24 has a front flange 26 which abuts a correspond¬ ing front flange 28 of the shell 12, as shown. An elec¬ trically energized light source or bulb 30 is provided

on the glow ring 24 to illuminate the latter from the rear thereof, and/or to illuminate the interior of the shell 12. The bulb 30 is carried in a semi-cylindrical housing 32 that is attached to the glow ring 24 by means of a thin web-like support arm 33.

As is usual, the shell 12 has oppositely-disposed lanced spring fingers 34 which frictionally engage a cigar lighter ignitor plug (not shown) of a type similar to that of U. S. Patent No. 3,870,857 above identified, to normally frictionally retain the ignitor plug in a shallow storage position in the shell.

The entire disclosure of U. S. Patent No. 3,870,857 and the entire disclosure of U. S. Patent No. 3,532,849 are specifically incorporated in the present application, by reference.

Referring again to Figs. 1 and 2, the inner end of the shell 12 has a transverse rear wall 36 with a central opening which receives a tubular boss or projection 38 of a ceramic insulating block 40 that is to be attached to the shell 12 in a novel press-fit manner. In this connection the block 40 is clamped in position by a push or press-fit fastener stud 42 which is particularly illustrated in Fig. 5. The stud 42 also mounts in the usual manner a known type of bimetallic clip means 46 that is insulated from the shell 12 while being electric¬ ally connected to the stud 42, at the front of the block 40. The bimetallic clip means 46 comprises a pair of opposite fingers and a central hole to receive the stud

42, the outer end or tip 48 of the latter being headed over the clip means so as to form a secure mechanical connection as well as a permanent electrical connection thereto. The fastener stud 42 has a shank 50 which extends through the ceramic block 40 and projects through the transverse bottom wall 36 of the shell 12, as shown. The ceramic block 40 is shown as having keying recesses 52, Fig. 1, in its rear surface, and the transverse rear wall 36 of the shell 12 has two teeth 54 struck there¬ from, as in the figure, such teeth being received in the keying recesses 52 of the block and preventing relative turning movement between the block and shell.

In accordance with the present disclosure, the assemblage 14 comprising the assembler and connector plug that is carried by the shell 12 at the rear thereof, is constituted in the main as the hollow, cup-shaped and generally cylindrical molded plastic plug body having the walls 17 and 56, such body 15 having molded in it the contact prong members 18, 20 and 22 to provide char¬ acteristics whereby the prong members not only consti¬ tute the spade terminal formations shown and are adapt¬ able for use with a standard electrical connector recep¬ tacle of a vehicle wiring harness, but also constitute a sturdy mechanical retention means between the plug body 15 and shell 12. The assemblage 14 further includes pro¬ vision for a safety bimetal shunt which is to be carried inside the body 15. The said assemblage also features

the provision of an exteriorly-accessible electrical contact for selective energization, through one of the contact prong members, of an electrically energized source of light for the glow ring 24, and/or the interior of the shell 12.

The plug body 15 is preferably molded in the cup shape shown, forming the recess 16 with the wall portion 17 defining the bottom of the recess. In the disclosed embodiment, the three contact prong members 18, 20 and 22 are illustrated as being molded in place, so as to be permanently embedded in the plug body 15.

Referring now to Fig. 7, the contact prong member 22 is shown separately as having the base portion 60 and an offset connector portion 62 which latter is disposed at the edge of the portion 60. The base portion 60 also has, for securement of the assemblage 14 to the shell 12, the opening 64 to receive with a press fit the shank 50 of the stud 42, as will be explained below. Under¬ neath the base portion 60 are the important contact sur- face areas 66a that surround the opening 64. The contact prong member 22 is molded in the plug body 15 in such a position that its base portion 60 and the contact surface areas 66a thereof are exposed exteriorly of the plug body 56, thereby to be accessible to the fastener stud 42 for mechanical retention thereby and electrical contact therewith, as in Fig. 1.

In providing access for the connection between the fastener stud 42 and the base portion 60 of the prong

member 22, the plug body 15 is molded with a transverse access groove or relief 62a, Figs. 1 and 2 , and the base portion 60 of the prong member is exposed at the bottom of the access groove 62a. A central hole 64a, Fig. 3, in the wall portion 17 of the plug body 56 receives the rightmost end of the fastener stud 42 as viewed in Fig. 1.

Further, in accordance with the present disclosure the said rightmost end of the fastener stud 42 is pro- vided with a series of generally circular barbs 65, Figs. 1, 2 and 5, which become forcibly engaged in the opening 64 of the base portion 60 of the contact prong member in the manner of a "push-on" fastener when the shank 50 of the stud 42 is forced against the opening 64 of the prong base. The barbs 65 forcibly engage and bite into the walls of the opening 64 in one or more annular zones, depending on the spacing between the barbs 65. In a pre¬ ferred embodiment, the prong member 22 is stamped of cold-rolled steel, plated, and the thickness of the base portion 60 of the prong member is on the order of 1/32", which is considered sufficient for effecting a strong mechanical retention between the stud and base portion.

Also there is provided a bimetal safety shunt 66 in the access groove 62a, such shunt being particularly illustrated in Fig. 9. The shunt 66 has a central mount¬ ing hole 68, and has two oppositely extending legs 70, 72, each leg having a generally U-shaped or channel-like cross sectional configuration, with the openings of the

channels facing one another. Each of the legs 70, 72 has a free end, constituting contactor portions 74, 76 respectively.

Referring again to Figs. 1 and 2, the bimetal shunt 66 is mounted against a shoulder 78, Fig. 5, of the shank 50 of the fastener stud 42, and is sandwiched or pressed between said shoulder and the contact surface areas 66a of the base portion 60 of the contact prong member 22. Pressure is maintained on the surface areas 66a by the bimetal shunt 66 as a consequence of the forcible inser¬ tion of the barbs 65 of the fastener stud 42 into the opening 64 in the base portion 60 of the contact prong member 22. The securement of the bimetal shunt 66 occurs simultaneously with the assembly of the plug body 15 to the shell 12, as will be outlined below.

The fastener stud 42 is preferably constituted of tempered brass, and for such metal of the stud, the con¬ tact prong member 22 is chosen as steel, plated. During the insertion of the stud 42 into the opening 64, Fig. 7, the barbs 65 deform somewhat, and permanently retain the base portion 60 of the contact prong member 22 (and the surrounding plug body assemblage 14) as a consequence of the press-on operation.

The second contact prong member 18 is particularly illustrated in Fig. 8, comprising a spade terminal por¬ tion and a base 80. This contact prong member 18 is utilized in establishing the electric "ground" leg of the cigar lighter circuit, which has the same electrical

potential as that of the shell 12. The contact prong member 18 is also molded or embedded in the plug body 15, and located such that its base 80 is exposed exteriorly of the plug body, Fig. 2. In accomplishing the electrical connection of this contact prong member 18 to the shell 12, there is provided at the inner end of the plug body 15, a generally flat depression 82, Fig. 1. Disposed in the depression 82 is a resilient, bowed spring washer 84, particularly illustrated in Figs. 10 and 11. During the attachment of the plug assemblage 14 to the shell 12, the washer 84 becomes flattened, and the resulting pressure exerted by the flattened washer 84 maintains a firm engagement between the transverse wall 36 of the shell 12 and the base 80 of the contact prong member 18, as shown in Fig. 2. In Fig. 8, the base 80 is shown as a generally crescent- shaped sector. The base 80 is integrally formed with the spade terminal portion of the member 18, as is under¬ stood. In use, the base 80 is resiliently engaged by the spring washer 84 so as to maintain electrical continuity between the contact prong member 18 and the shell 12. Preferably the entire spring washer 84 is copper plated, so as to minimize any metal fusing and thereby facilitate automatic re-setting of the shunt following an overheat condition, as can now be understood.

As seen in Fig. 2, the front end of the plug body 15 is provided with oppositely disposed keying recesses 86, which receive cooperable lugs 88 struck from the

transverse wall 36 of the shell 12. In addition, prefer¬ ably one of the lugs 88 engages the contact prong member 18, also as seen in Fig. 2. In Fig. 10 there are illus¬ trated two rectangular keying holes 90 in the bowed spring washer 84, which also receive the lugs 88 struck from the transverse wall 36 of the shell 12.

The third contact prong member 20 is particularly illustrated in Fig. 6, and is employed to establish a third electric "leg" of the cigar lighter circuit, name- ly that associated with an electrical load such as the electrically energized source of light represented by the lamp 30 in Fig. 2. The contact prong member 20 com¬ prises a spade terminal portion, and a contact ring 92. The member 20 is molded or embedded in the plug body 15, and located so that the ring 92 thereof is exposed at the outer cylindrical surface of the body walls 17, 56, as in Figs. 1 and 2. The ring 92 is electrically insulat¬ ed from both of the other contact prong members 18 and 22, and is intended to be engaged by a cooperable exter- nal contact 94, for example, in a ring or band 96 that is physically connected to the lamp housing 32. The band 96 can take the form of an insulating plastic ring hav¬ ing an internal annular groove. The contact strip 94 is carried in the internal groove of the band 96 as in Fig. 2, and is electrically connected to one side of the lamp 30 by means of a conductor 98 in the lamp housing 32, shown in dotted outline in this figure. The other elec¬ trical connection to the lamp 30 is effected by a spring

finger 100 that extends from the lamp housing 32, through a hole in the support arm 33, and bears with frictional engagement against the exterior surface of the shell 12, which is at electrical ground potential. The arrangement is such that an electrical connec¬ tion is effected between the strip 94 of the contact prong member 20 and the lamp 30 for any of a multiplicity of angular orientations of the lamp 30 and band 96 with respect to the plug body 56. In the disclosed embodiment, the contact strip 94 is shown as being annular. In prac¬ tice, with the ring or annular contact 92 constructed as shown, the conductive strip 94 can take the form of either a point contact (not shown) , or alternately a segmented contact (not shown) extending through a small angle. As presently understood, the strip 94 occupying the internal groove of the band 96 preferably would be provided with a spring characteristic, similar to a wave washer, to thereby cause a resilient pressure therefrom on the ring 92. Fig. 1 illustrates diagrammatically the vehicle's storage battery 102 and a protective, circuit-opening fuse 104, connected via an electrical lead 106, to a contact prong 108 in the power supply receptacle (not shown) which is insertable in the plug assemblage 14 for engagement with the prong 22.

In assembly of the combined assembler and connector plug assemblage and shell, the stud 42 having the captive bimetallic clip means 46 is first inserted in the ceramic

block 40, and the resultant sub-assembly thereafter in¬ serted into the shell 12 such that the shank 50 projects from the rear of the transverse wall 36 thereof. Then the spring washer 84 is placed on the back side of the wall 36 with its hole aligned with the boss 38 of the ceramic block. Following this operation the bimetal shunt 66 is placed on the shank 50 in engagement with the shoulder 78 thereof, and the molded plug assemblage 14 comprising walls 17, 56, and spade-type terminals 18, 20 and 22, installed on the stud shank, such that the base portion 60 is forcibly fitted onto the barbs 65 of the stud shank, causing a moderate deformation of the barbs and resulting in a permanent retention of the assemblage 14 on the rear of the shell 12. During the assembly the bowed spring washer 84 flattens somewhat, causing it to resiliently engage both the conductive surface of the rear wall 36 and the base 80 (Figs. 2 and 8) of the con¬ tact prong member 18. At the same time, a firm mechanical retention is established between the stud 42 and base portion 60 (and plug assemblage in which it is molded) . Also, the bimetal shunt 66 is firmly mechanically secured between the shoulder 78 of the stud shank, and the base portion 80, Figs. 2 and 7. By such an arrangement, the bimetal shunt 66 is held, simultaneously with the secure- ment of the base 80, spring washer 84 and wall 36 of the socket member or shell 12. The flattening of the washer 84 absorbs any looseness or play which might

otherwise occur between the wall 36 and base 80, to assure good electrical contact of these parts.

In operation, in the event of an overheat condition in the shell 12, the bimetal shunt 66, being constituted of two layers of metals of dissimilar coefficient of thermal expansion, undergoes flexing; in particular, the contactor portions 74, 76, Fig. 9, flex toward the left in Fig. 1, eventually electrically contacting the spring washer 84, and short-circuiting the contact prong ter- minal base portion 60, through the washer 84 to the shell 12, which latter is electrically at ground potential. The fuse 104 thus blows, and the cigar lighter circuit is protected against further heating or energization.

Upon cooling of the bimetal shunt 66, it will tend to spring back to the position of Fig. 1 if it has not become welded to the washer. Thereafter, re-energization of the circuit through a replacement fuse 104, will enable further cigar lighter operation to occur. If, however, the bimetal shunt 66 has become "welded" to the washer 84, then upon such re-energization, the weld will be heated momentarily and broken, so as to release the shunt 66 and enable it to spring to its normal position. Thus, any tendency for fusing of the contactor portions 74, 76 to the washer 84 can be minimized by having the spring washer 84 copper plated. The dissimilar metals, copper plate on the spring washer 84, with the alloy metal of the shunt 66, tend to resist formation of a permanent weld between the shunt and the washer, which

might otherwise render the lighter unuseable following an initial actuation of the bimetal shunt 66 as a result of an overheat condition having been experienced.

From the above it can be seen that there has been disclosed an improved combined assembler and connector plug for a cigar lighter socket, the device being especially adapted for use with standard automotive-type electrical connector receptacles of a push-pull type commonly in use today with vehicle wiring harnesses. These receptacles include, specifically, those manufac¬ tured by Packard Electric, AMP, and others, known as, "2.8 mm. female 12-volt electrical plugs." The "2.8 mm." figure refers to the width of the "spade" part of the contact prong members 18, 20, 22, with which such elec- trical plugs are to mate.

The disclosed safety bimetal shunt arrangement min¬ imizes potential fire hazards from inadvertent overheat¬ ing of the lighter. Since the shunt is mostly concealed in the connector receptacle, any arcing which may occur during operation of the shunt is safely confined; in addition, in a preferred embodiment the shunt, although confined as such, can be easily viewed for inspection purposes, from either of two opposite sides of the cigar lighter receptacle, thus facilitating troubleshooting in the event of inadvertent malfunction. The viewing capa¬ bility does not sacrifice the safety feature provided by the confinement of the bimetal shunt, however.

The unit is especially compact, easily installed, and features high contact integrity, thereby largely eliminating potential problems of inadvertent contact heating resulting from poor electrical connections arising between the various parts.

Essentially two separate or independent electrical circuits are provided, one for the ignitor plug which is adapted to be received in the cigar lighter socket mem¬ ber, and a second for an electrically energized load or light source that is used to illuminate a glow ring located at the bezel of the socket member, and/or illuminate the interior of the socket member, thereby facilitating use of the cigar lighter under marginal lighting conditions. With the disclosed constructions, there is realized a cigar lighter and connector therefor which are char¬ acterized by a greatly simplified, automated assembly capability of the various components. In spite of the ease of assembly, there is still retained the reliabil- ity and functionality of the combined cigar lighter sock¬ et member and the assembler and connector plug, the two being essentially unitary in their final configuration, and capable for use directly with an electrical wiring harness connector receptacle of conventional construc- tion and of a type which has become standard in the automotive industry today.

The disclosed device is thus seen to represent a distinct advance and improvement in the automotive cigar lighter field.