US3535667A - Electrical safety device - Google Patents

Description

ELECTRICAL SAFETY nnvxcs Find D. 6, 1968 r v INVENTORS HENRY c. HARNIS'I-LJR ANTHONY 1'. ORSELLO 3,535,667 ELECTRICAL SAFETY DEVICE Henry C. Hamish, Jr., Brantwood Terrace, Hackettstown, NJ. 07840, and Anthony J. Orsello, Elcock Ave., Boonton, NJ. 07005 Filed Dec. 6, 1968, Ser. No. 781,726 Int. Cl. H0111 85/54 US. Cl. 337-197 Claims ABSTRACT OF THE DISCLOSURE A safety device, for household, commercial, and industrial use, comprising an electrical intercoupling. The intercoupling device carries an electrical socket at one end, and has prongs extending from the other end thereof, the socket for receiving a plug-connector and the prongs for engaging a socket of a wall outlet, or the like. Throughconnecting' strips electrically interconnect the socket and prongs, however, one of the strips, comprising a safety link, has a current-rated fusible section.

This invention pertains to safety devices and in particular to safety devices useful in the household, as well as in commercial and industrial use, and protective with respect to electrical current.

Safety devices which protect against excessive current are notorious in the prior art, and involve fuses, circuit breakers, and the like, interposed between the external power lines and the several line circuits, mounted in fuse boxes. Typically, one fuse or more is interposed between the main power lines and the several line circuits, then each line circuit is separately fused. Such fusing functions well for the purposes involved. But it is inadequate toward inhibiting an excessive current drain by any one electrical unit on any one line.

By way of example, a household line circuit which is fused-rated for thirty amperes of current may have a seventy-five watt table fan operating therefrom. As the fan will demand less than one ampere of current it will have a lightand lightly insulatedline cord. Now, it is not uncommon for a househoder to leave electrical units in unattended operation. Clothes dryers, freezer units, etc., are commonly in operation out of sight of the householder. Not infrequently, in summer season for instance, it can be expected that the house may be absented for hours while the table fan, let us say, is left operating. Now, should the fan become defective, developing a short circuit perhaps, its seventy-five watt load will thereby be shunted. The short circuit will pass more and more current-at least up to the thirty amperes available through the remote fuse box thirty ampere fuseuntil, hopefully, the latter fuse opens the line circuit.

Before the basement thirty-amperes fuse opens, the light line cord of the fan may well be a charred ruin. All too frequently, however, the overheated line cord will flame, and the house will become another statistic of the National Fire Protection Association. It is this Association which advises that fire damage to American homes runs to over three hundred millions of dollars each year; on the basis of national averages, one home in every neighborhood, each year, will have a fire, and every day seventeen peoplemostly the young and ageddie in these fires.

Clearly, what is needed then is a more facile safety device protective, certainly, of the home, and of commercial and industrial establishments also, against the lethal albeit useful flow of electrical current.

It is an object of our invention, therefore, to teach a safety device for household and general use especially configured for interpositioning between the using elec- United States Patent 0 3,535,667 Patented Oct. 20, 1970 trical unit and the fuse box fuse for the line circuit.

Especially is it an object of our invention to teach a safety device of the type noted having means automatically operative for interrupting a fiow of electrical energy upon said flow exceeding a predetermined rate.

A feature of our invention comprises the provisioning of an intercoupling device for electrically connecting between electrical connectorssuch as a plug and a socketsaid device having a safety link with a current-rated fusible section therein.

Further objects and features of our invention will become more apparent, by reference to the following description taken in conjunction with the accompanying figures, in which:

FIG. 1 is a side elevation view, partly in section, depicting the deployment of an electrical line circuit in a household, according to the practices of the prior art;

FIG. 2 is a side elevational view, partly in section, of the safety device according to our invention, in one embodiment thereof;

FIG. 3 is an end view of the safety device of FIG. 2, looking along the prongs extending therefrom and towar the housing thereof;

FIG. 4 is a side elevational view, partly in section, of an alternate embodiment of the invention; and

FIG. 5 is an end View of the safety device of FIG. 4, partly in section, looking along the prongs thereof toward the housing.

As shown in FIG. 1, a part of a house 10, including a living room 12 and a kitchen 14, has a line circuit 16 in service thereof. Line circuit 16 proceeds from fuse box 18 situated in the basement, lbeing fused by a fuse 20. The fuse box 18 receives power lines 22 therewithin.

Line circuit 16, through fuse 20, supplies electrical current to outlets 24,26, 28 and 30, which power a number of electrical units. Thus, outlet 24 powers an electrical clock 32 rated at seventy-five watts, and a standing lamp 34 rated at three hundred watts. Outlet 26 provides power for television set 36, and outlet 28 supplies toaster 38. Outlet 30 supplies current for a range lamp 40, and the line circuit 16 further provides power to an exhaust fan 42.

Typical wattage ratings for units such as the television set 36, toaster 38, range lamp 40, and the exhaust fan 42, are, by way of example, 300 watts, 1100 watts, 60 watts, and 60 watts respectively. The wattage rating for line circuit 16, then, would dictate its fusing, at fuse box 18, for twenty amperes.

Now, consider, there is no unit on line circuit 16 which might be left operative and unattended excepting perhaps lamp 34 or electrical clock 32. Actually, the very nature of electrical clocks mandates their continuous operation. Therefore, in both the presence and absence of the householders, clock 32 will be continuously operative. Should clock 32 develop a direct short circuit, its normal demand of current of less than one ampere will not save the situation. The clock motor, the seventy-five watt load, will be shunted by the short circuit, and clock 32 will pass up to twenty amperes of current therethrough. Before the line circuit fuse 20 in fuse box 18 opens, the line cord of clock 32 will overheat, smoke, perhaps flame. Adjacent curtains, if any, could flame. Outlet 24 likely will overheat, and the wires of circuit 16, which convey current to outlet 24 also are subject to overheating, charring, and flaming. It is the avoidance of this everpresent hazard which the teaching of our invention provides.

If the line cord of clock 32, and the outlet 24 had a safety link connector interposed therebetween, especially such a connector having means automatically operative for interrupting a flow of electrical energy therethrough upon said flow exceeding a predetermined rate of flow,

then inordinate current conduction can be positively interdicted.

The device 44 of our invention, shown in FIG. 2, provides for this safety interdiction.

Device 44 comprises a housing 46 which mounts at one end thereof a plurality of sockets 48. Sockets 48, as FIG. 2 illustrates, are recessed in housing 46 therein to receive the mating prongs of an electrical plug. Sockets 48 constitute that which is customarily identified as a female connector. At the other end of housing 46 are supported therein, and extendibly therefrom, prongs 50. Only one prong 50 is visible in FIG. 2 as the other thereof is directly behind the one shownthe two being supported in parallel. A connector strip 52 electrically interconnects one of said sockets 48, the latter being of the customary metal sleeve type, with one of said prongs 50, and said prongs being of the customary knifetype known as male connectors. A safety link connector strip 54 electrically interconnects the other of said sockets 48 with the other of said prongs 50. As seen in FIG. 3, strip 54 has a constricted portion which comprises a fusible section 56. Fusible section 56 will open and separate the respective ends of safety link strip 54 upon the conduction therethrough of excessive current.

Device 44 can be configured for the current-rating warranted by any given diversity of electrical units. Thus, where in a household, for instance, a continuously-used electric clock is current-connected to an electrical source-as at outlet 24, as shown in FIG. la oneampere-rated device 44 would be used. The line cord of clock 32 would have the plug connector at the end thereof engaged with sockets 48 of our device 44, and prongs 50 of our device, would be inserted into outlet 24. Then, upon clock 32 short circuiting, the line cord therefor, and line circuit 16 as well, will never pass the potentiallylethal and otherwise wholly available twenty amperes of current. When a short circuit in clock 32 passes only a first ampere of current, fusible section 56 Will melt and open. Thus, only the clock-serving branch of line circuit. 16 will be interrupted. Outlets 26, 28, and 38 will still be operative, and service to exhaust fan 42 will continue. Finally, it is to be noted that the second section, i.e., the lower section (as shown in FIG. 1) of outlet 24 is stilloperative for service. Especially it is to be noted that no fuse in fuse box 18 needs replacement; the fuse 20, for line circuit 16, will not have opened.

A television set having a three hundred watt rating would have a fouror five-ampere device 44 constantly interposed between the plug-connector therefor and the outlet to which it always connected. A one thousand watt electric iron would be throughconnected with the electrical source therefor through an eleven or twelve ampere device 44.

Our invention, then, is not limited to a safety device 44 of any given ampere rating. Our invention contemplates a broad spectrum of devices 44 having fusible sections of varied fusible capacities.

With the use of our device 44, at critical or all electrical outlets and connections, a household may be absented for hours, for weekends, for several weeksfor vacations and the like-with one or more electrical units continuously operative, without risk of fire to the house.

The frequency with which a basement-located, or otherwise remotely located line circuit fuse needs replacement is markedly reduced, perhaps eliminated, depending upon the universality with which our devices 44 are deployed throughout the household.

House line circuits, such as those of line circuit 16 of FIG. 1, never have any one unit; iron, toaster, clothes dryer, or whatever, powered thereby which unit requires all the current for which the line circuie is rated and holds available. That is to say, a line circuit rated for fifteen amperes will have as its greatest single loading hundred watt appliance, such as a television set for instance. A line circuit rated for twenty amperes will likely number among the units it serves a fourteen hundred watt rotisserie or a sixteen hundred watt hot plate. Therefore, it is latently dangerous, an ever-present invitation to disaster, to ill-protect the lightly insulated, lowcurrent units and appliances, which are carried on the same line with some heavy-loading units, against short circuiting which can cause minor or major conflagrations. To put it bluntly, a simple, three-dollanvalue, sixty-watt bed lamp short circuiting a twenty-ampere line could reduce a thirty-thousand-dollar home to ashes. Tragically, it happens. Every minute of the day an American home is destroyed or damaged by firesays the National Fire Protection Association.

Our device 44 is of inordinately simple construction. Housing 46 is of non-combustible, flameand heatresistant plastic composition, and sockets 48, strips 52 and 54, together with prongs 50, need only be supported in a plastic mold until housing 46 formed therein firms up. It is contemplated that prongs 50 would be supported above a mold, suspending strips 52 and 54 and sockets 48 connected thereto within the mold, until the plastic composition solidified. But the manner of construction is not the subject of this invention; any one of several methods of fabrication will occur to those skilled in the art to which our invention pertains. Our invention comprises the overall device 44, however derived, a simply-formed device of inexpensive manufacture which markedly inhibits the risk of home, commercial, and industrial fire through electrical failures.

As it is now, in the prior art, a fuse box fuse will blow, cutting all power to a line circuit, or cutting all power to the home, commercial establishment, or Whatever. With this occurrence it is now known, initially, whether the fuse failure proceeded from an overloaded line circuit or a short circuit in some one unit. Should the latter be the case, often it is not readily to be determined Which one unit shorted out. Overheating and charring may have occurred behind the walls, with little or no visually discernible evidence of overheating in any given unit. Of course, replacing the fuse does not solve the problem; this but re-introduces the fire risk. Yet, power must be re-introduced before it can be determined which using unit shorted out and is no longer operative. If the faulty unit is an iron, television set, or the like, one will have to wait for a considerable lapse of time to be certain that the suspect unit is not heating upand will not heat up. And during this lapse of time, wallconfined line circuit wires can be cooking again-until the replacement fuse blows, or the defective unit is identified. Our device 44 completely avoids this problem. Where all units on a line circuit are safeguarded by our devices 44, any one unit thereon which fails to operate, after any lapse of time, is readily identified as the defect1ve unit; all other units continue to operate. Further, our devices 44 insure that, whatever the lapse of time, the wall-confined line circuit wires will never carry the wholly available twentyor thirty-ampere current therethrough.

In FIGS. 4 and 5 we teach an alternate embodiment of our device which is usable with the well-known grounded plug and outlet. This embodiment teaches a safety device 58 which has a ground connection provisioned therein. A female-type ground socket 60 is provisioned, and a ground prong 62, the two being conductlvely interconnected by means of a connector strip 64. Prongs 50, being identical with those of the FIGS. 2 and 3 embodiment, are provisioned for engagement with the electrical outlet, and sockets 48 again, with connector strips 52' and 54' electrically interconnecting therebe tween. The safety link connector strip 54 has a fusible section 56' therein, shown in FIG. 4, which openslike section 56 of the FIG. 3 embodiment-when the current passing therethrough exceeds the current rating for which the section is designed.

In both the embodiments, device 44 and device 58, we teach the use of connector strips 52 and 52', and safety link connector strips 54 and 54, the latter having constricted fusible sections 56 and 56', respectively. This is only exemplary of our invention. Connector rods could be used as well, in lieu of strips, the rods having fusible sections characterized by reduced diameters.

Accordingly, while we have described our invention in connection with specific embodiments thereof, it is to be clearly understood that this is done only by way of example and not as a limitation to the scope of our invention as set forth in the objects thereof and in the accompanying claims.

We claim:

1. A safety device, comprising:

a housing;

first means for mechanically intercoupling a plurality of electrical connectors;

said first means including at least a pair of electricallyconductive sockets disposed in parallel and embedded in said housing in a given longitudinal orientation, and at least a pair of electrically-conductive prongs disposed in parallel and partially embedded in said housing and partially extending therefrom in a position rotated at least 90 degrees of arc from said given longitudinal orientation; and

second means for conducting a given, predetermined rate of flow of electrical energy from at least one connector of said plurality to at least another connector of said plurality;

said second means including at least a pair of electrically-conductive strips irreplaceably sealed within said housing, each of said strips providing for electrical conductivity between one socket of said pair thereof with one prong of said pair thereof, each of said strips being connected to one socket and one prong, and at least one of said strips includes a fusible section automatically operative for interrupting said energy flow upon said flow exceeding said predetermined rate.

2. The invention, according to claim 1, wherein:

one of said strips lies in a given plane;

another of said strips lies in a different plane which transverses said given plane; and

a further one of said strips lies in a plane which transverses both said given and different planes.

3. The invention, according to claim 1, wherein:

said housing has flat, oppositely disposed ends;

one end of each of said sockets opens on one of said flat ends, said sockets extending longitudinally into said housing more than half the distance subsisting between said flat ends disposing the other ends of said sockets in near adjacency to the other of said fiat ends; 7

said prongs have terminal ends within said housing,

said terminal ends being disposed substantially midway between said fiat ends; and

said strips are connected to said terminal ends of Said prongs and said other ends of said sockets.

4. The invention, according to claim 1, wherein: said first means comprises three electrically-conductive sockets, and three electrically-conductive prongs; said second means comprises three electrically-conductive strips; and

one of said sockets, prongs, and strips comprise a grounding throughconnection. 5. The invention, according to claim 4, wherein: said strips lie in parallel planes.

References Cited BERNARD A. GILHEANY, Primary Examiner D. M. MORGAN, Assistant Examiner US. Cl. X.R. 337 269

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