WO2003067717A1

WO2003067717A1 - Electrical extension cord with voltage indication

Info

Publication number: WO2003067717A1
Application number: PCT/SE2002/000011
Authority: WO
Inventors: Gerth Ohman; David Gidlof
Original assignee: Gerth Ohman; David Gidlof
Priority date: 2002-01-04
Filing date: 2002-01-04
Publication date: 2003-08-14
Also published as: AU2002219743A1

Abstract

This invention is comprised of a cord (1) that has plugs (3, 4) on both ends. These plugs have illumination devices (5’, 5’’) that glow if the cord (1) is in contact with voltage. The illumination devices (5’, 5’’) of the plugs (3, 4) are placed on the plugs rear areas and are preferably comprised of low energy lights. In order to achieve full electrical and usage safety, these lights are first attached to ordinary cord fasteners within the plugs (3, 4) and then oriented back toward the relief clamp (19) which can be found in most plugs (3, 4). Furthermore, the invention provides a functional chain, which permits the cord (1) to be used as a control instrument for checking if the cord is in contact with voltage. This controlling function can be carried out at a distance because the illumination device (5’, 5’’) is positioned in the direction of the cord (2) and is not obscured by any obstacles in or on an outlet socket or by the insertion of the outlet plug (3) into the wall outlet (7).

Description

Designation of Invention

Electrical extension cord with voltage indication

Technical Area of Invention Electrical and electronic cords with one or more diode lamps on their plugs for ocular indication of voltage within the cord.

General Description of Invention

Prior art

Within this technical field there are a multitude of different cords and plugs. Cords can be found with light diodes that glow, for example when their plug switches are turned on. Even electrical outlets have illumination. Stairwells are often equipped with illuminated switches and outlets that can be seen in the dark. So called ground fault interrupting device are also equipped with light diodes that glow as long as ground fault interrupting device has not been triggered. This technology is inexpensive and relatively reliable. Furthermore, there can be found different types of wall outlets, like the ones in stairwells, which are illuminated as long as voltage exists, for example in outdoor outlets. In a special patent review, number Dnr PO 1094/00 dated May 16, 2000 the following patent documents have been found regarding the described invention. Patent document numbers:

DE 32 14 484 shows a voltage indicator that connects to a socket with a plug. An illuminated indicator is attached in connection to the socket.

DE 296 19 510 shows a light diode fitted into a socket or outlet indicating voltage.

DE 43 40 962 shows a socket with an illuminated device fitted on it.

So called plug assemblies and electrical boxes in different designs often with light indicators in similar forms can also be found. Even circuit breakers of different designs use light diodes to indicate that they are functioning. Current procedures can be described as follows. Usage of cords in the home, manufacturing industries, the computer industry, contracting and other workplaces implies the need to insert electrical plugs into wall sockets and other outlets, after which the cord is laid out to where it is needed. On other occasions the cord is first laid out and then connected to a nearby socket or outlet. Independent of method used, in neither case can there be absolute certainty as to whether there is current in the cord. In some cases it can be determined that current has reached the cord's extension plug, but if that light diode is not illuminated it is impossible to say if the problem lies within the wall socket, the socket plug, the extension plug or the cord itself. This often results in discarded cords without further tests. Worse yet, someone could try to use the discarded cord, with risk for accidental electrocution. There is also the possibility of other defects not mentioned here. Methods for defect detection are lacking. Similar problems can arise with cord devices that can be rolled up in many different ways. Cord devices are often equipped with plugs that prevent twist damage to the cord, but all too often problems arise anyway and there is no voltage. Even if the indicator diode in an outlet is illuminated, there could still be faults with the socket, the plugs, the cord, the cord device or the plug or socket of the apparatus that is to be used. Even here are methods for defect detection lacking. Experience from personal tests show that the minimal required need is for an illuminated device on the extension plug that is to be inserted into the desired apparatus. In this way, a simple and safe indication of how far the voltage has reached is received. Consequently, there is a great need for technical development within this area in order to accomplish this.

The Inventions Newness in Regard to Existing Technological Solutions

This invention utilizes a technical solution in order to attain optimal electrical safety when using electrical or electronic extension cords. To better understand this invention and its level of inventiveness, current technical procedures have been described in the previous section. Especially important aspects of this invention are its ability to facilitate a speedy detection of defects and safety hazards. This invention aims not only to apply new technology, but even to introduce new methods of use based on this technology.

This invention, which will be presented in detail in the next section, includes in part a technical product as well as an ergonomic procedure there mans natural behavior is utilized in the technique.

Upon observation of a cord, the eye follows the cord to a socket, which can be lying either free or inserted into a wall outlet. This wall outlet can in turn be built into the wall or a fuse box or even furnished with a protective cover, which is not at all uncommon. Other variations also exist. This obstructs or makes it virtually impossible to see an illuminated indicator on a plugs side or front, which is what current technique offers.

When the plug is inserted into a wall outlet or other socket, the plug becomes a part of the outlet or socket by this insertion. In this way the front part of the plug and a sizable portion of its side are incorporated into the wall outlet or other socket. This in combination with protective covers, the cord itself (which may shade the socket from light), dirt or for example snow, obscures the ability to see clearly if the cord is in contact with voltage.

According to the patent review PO 1094/00, as shown in the above Existing Technology section, there exist illuminated devices built into sockets and plugs. DE3214484 from 1982 has illumination in the direction from the socket or toward an observer looking directly at the socket. DE4340962 from 1993 has illumination from the side. Finally, DE29619510 from 1996 has illumination via a serial diode between the poles in the socket, standardized measurement of 20 mm. The technical advantages of DE29619510 can not be considered acceptable. The mentioned patent documents provide illumination in both plugs or housing for extension plugs before the so called relief clamp. This clamp holds the cord so it cannot be pulled loose from the socket. The clamp is an instrument of attachment that holds the plug in the socket.

Reverse illumination in DE29619510 is not possible or highly impaired. In contrast to

DE29619510, the invention presented here provides voltage indication from the cord side of the plug. Nowhere in the reviewed documents has such a solution been presented. Even self-conducted searches, such as U.S 5924889 have not revealed any similar solutions.

Illumination within plugs and sockets is nothing new within itself, but the placement of the light source determines the technical function of the invention. Herein lies the potential for development.

DE29619510 has chosen to use a serial coupled light diode with an ordinary diode. The use of the standardized 20 mm measurement indicates that the invention must be drawn straight between the poles without any bends. Placement is in front of the clamp that is a safety and attachment device within the socket. It is a technical impossibility to bend, rotate or draw forward this illuminated device in order to fit the clamp. It is not intended either. DE29619510 stretches back from a fixed position in accordance with the cord's fastening screws to a functional position approximately in the middle of the socket and at some distance in front of the clamp. Functionally, this implies that there arise elements from the fastening screws to the diodes and light diodes fixed positions.

Extension cords are often haphazardly handled, throw about, battered, squeezed and/or are exposed to vibrations or the elements making this design technically weak. Material degradation will soon follow and eventually lead to faults that will impair stop usage. This technique has not been successful on the market. DE29619510 is dependent of DE4340962 and is a further development. The presented technical difficulties of extension cords are in need of technical innovation. Market demand recognizes the need for solutions that will provide voltage-indicating cords that are user friendly and safe, in other words provide good ergonomics. These technical difficulties have long been a problem, but they have not been properly identified. The presented invention supplies a new solution to these problems. By a better positioning of illuminated devices it is possible to produce a uniform model that will enable the user to ascertain whether voltage exists, providing a high level of technical safety.

The technical safety aspect is further legitimized by use of the clamp, which is used by virtually all sockets. The presented invention is attached with ordinary screws in a backward position against the clamp where it is locked into position. Sockets have guidelines for the housing that guide the housing into the correct position over the inner contact areas and in this way always insure a correct insertion. This will favor automation in the manufacture of this invention. An industrial application is thereby insured because these cords can be produced in large series of high quality.

Technical applications are not limited to consumer and commercial markets for extension cords, and other electrical cords for various usages, but can also be used within electronics, computer and digital industries, thus providing the same solutions for low voltage applications. Fuses can be mounted in the sockets 3,4 in the same way as illuminated devices 5', 5".

Who asked for a microwave oven before it was invented? Problems with cords have existed for a long time and have gone without proper identification. The problem can therefore be viewed as new because technical ergonomics have immediate use of these cords and because of this a high level of inventiveness exists. Never before has anyone laid forth a technical solution for cord utilization that is so suited for human use.

Detailed Description of the Invention

The invention, electrical extension cord with voltage indication and usage procedures for said invention will be described with help of the following figures:

Fig. 1

Shows the voltage indicating cord 1 comprised of cord 2, plug 3, outlet 4, illuminating device 5 ',5" and plugs 3,4 rear area 15', 15" more precisely defined as the area from or in direct contact with plug 3,4 clamp 19 and to the back end of the plug where the cord exits the plug 3,4. Fig. 2a Shows plug 3 from the side. Angle alpha describes how some plugs bend out in an angle or taper off. In most plugs 3,4 the clamp 19 is placed in direct connection to angle alpha before the plug 3,4 narrows off.

Fig. 2b Shows plug 3 with its covering 14 lifted off. The clamp 19 and an extra clamp 19' are drawn in the figure.

Fig. 3

Shows plug 4 from the side.

Fig. 4a

Shows plug 4 from the top with illumination device 5" inside plug 4 cover 14 mounted to clamp

19.

Fig. 4b

Shows plug 4 from the top with illumination device 5" in an opening in plug 4 cover 14 mounted to clamp 19.

Fig. 4c Shows plug 4 from the top with an opening 8 and illumination device 5" within the cover. Opening 8 is equipped with an adhesive or other similar transparent material. In this way light from within plug 3,4 can reflect out through opening 8.

Fig. 5 Shows an alternative example of how the shown invention can be used in conjunction with wall outlet 7. Wall outlet 7 has illumination device 5", which glows when voltage is present och no plug 3 is inserted into wall outlet 7. If plug 3 is inserted into wall outlet 7 then the wall outlet's 7 illumination device 5" goes out. Plug 3 illumination device 5' switches on instead. This technique can also be used in night-lights or other lamps where it is not necessary for all control lights to glow simultaneously. There are similar needs in other areas of application. Shows cable holder 17, that has illumination device 5" on cable holder 17 and illumination device 5', 5" on plugs 3,4.

Fig. 7

Shows an example of how plug 3 can be inserted into wall outlet 7 and that wall outlet 7 covers a large portion of plug 3:s front and sides.

The invention's 1 technical construction and usage methods for technical safety will be described in-depth in the following section.

The voltage indicating cord 1 is mainly comprised of cord 2, which at each end has plugs 3, 4, preferably with outlet plug 3 in one end and an extension plug 4 on the other end. The cord 1 has a traditional construction, but in at least one end has a plug equipped with illumination device 5', 5". This illumination device 5', 5", preferably a lamp or other low energy light, is mounted on the plugs 3,4 internal contact point on the ordinary coupling site. Illumination device 5 ',5" is then drawn backwards to the plug's 3,4 rear area 15', 15" as defined in the above text.

The defined area 15 ',15" in and around clamp 19 and back toward where plug 3,4 ends and the cord 2 begins is an area that is visually open for a person attempting to insert or withdraw a plug 3,4. Nor is this area 15', 15" used when gripping the plug 3,4. The plug 3,4 can thereby be gripped and used for voltage detection with unhindered ocular inspection.

The rearward extension can be industrially accomplished in a predetermined way which would always allow for the illumination device 5',5" to come in contact with the plug's 3,4 cover 14 when the cover 14 is fitted over the internal plug parts. It is a well-known technical fact that plugs 3,4 have built-in guide lines, which ensures that the cover 14 is always correctly mounted during assembly. A technical advantage can be gained by reproducing the technique in this manner, which also allows for the construction of internal cavities in the cover 14. These cavities can have several uses, the placement of illumination device 5',5", light passage and for cord 3,4 ventilation which produces a degree of heat. Naturally, the material that is used can also be transparent or in this area be especially translucent via thinner material within the plug or alternative materials in the cover 14 that would provide an extra degree of transparency. The proximity between illumination device 5',5" and the cover's 14 wall, compare strength of the light, determines how easily light passes through the cover 14. The nearer they are the easier it is for light to pass.

Illumination device 5', 5" should always be placed in the plug's 3,4 rear area 15', 15", as defined above. In this way the light from illumination device 5',5"will not be diminished by the amount of material it passes through. If for example an outlet plug 3 is inserted into a wall outlet 7 or other socket a doubling of material could ensue. Optimal visual light efficiency can be attained in both plugs 3,4 if the illumination device 5', 5" is mounted on the rear area 15', 15", as defined above, and back to the area where the cord 2 exits the plug 3, 4. The illumination device 5', 5" is secured and fixed in position by mounting it on the clamp 19.

The main purpose of this invention is to orient the illumination device 5', 5" toward the plug's rear area 15', 15". By being able to chose the length of the illumination device 5', 5" opens the possibility of use in other technical areas, for example wall outlet 18, which self-conducted tests have shown.

Even manual assembly within a plug is simple. The cover's 14 screws are unscrewed from the inner parts of the plug. The screws that secure the cord 2 are loosened and an illumination device 5', 5", for example a lamp is screwed on. The legs of the lamp are fitted with a shrinkage device for increased safety. The lamps are currently available for other uses. Self conducted tests show that it is sufficient to place the lamp next to the cover's 14 rear wall 15', 15" to achieve illumination of the cover.

The lamp is secured in the clamp 19 or in an extra clamp 19'. Of course, the mounting devices for the illumination device 5',5" can be prefabricated and incorporated into the plug for quick and safe assembly.

It is not enough just to mount the lamp in a straight line between the poles, so to say plus and minus mounting screws within the plug. This is probably the reason why the DE29619510 has never become a successful product in the marketplace. Different wavelengths of light from the illumination device 5 ',5" can be used depending on what kind of material is used in the cover. Preferably, white light or warning light of orange color, or blue light with a mixture of red should be used in the illumination device 5', 5" in order to warn of danger. Similar products are on the market, but are not used in this way.

Self-conducted tests show where cavities or openings 8 have be introduced into the cover 14 indicate that the lamp always settles into the correct position via the guide lines that are found on the plug's 3,4 material, preferably on the cover's inside. Quick and efficient industrial production can be started in this way.

It is possible for different types of cord to achieve the same results. But that would require at least two cords, where the one cord 1 would use the illumination device 5' in its plug 3 and the other cord 1 would use the illumination device 5" in its plug 4.

By combining these cords together the same functional effect is produced. The plugs that have illumination device 5', 5" should be placed at opposite ends of this combination, but optimal safety is not attained in this manner. Defects could be present on either plug 3 or plug 4 before they are combined.

The best solution is to place the illumination device 5', 5" in both plugs 3,4 during production because this will only marginally increase costs when they are industrially manufactured.

This special description is an example of the inventions design and procedures for its use. There are, of course, other ways and designs for construction and procedures for its use that are supported by the general and special descriptions, the patent requirements and summary.

Claims

Patent Claims

1. Voltage-indicating cords 1, comprising a cord 2 that is equipped with an outlet plug 3 and an extension plug 4, whereby the outlet plug 3 and the extension plug 4 are both equipped with an illumination device 5',5", preferably a lamp or other low energy light, the lamp or other low energy light glows when the cord is in contact with electric or electronic voltage, characterized therein that that the illumination device's 5',5" component-legs screw into or are fastened in another way to ordinary holders for cord within the plug's 3,4 rear area 15', 15" and mounted on the relief clamp 19 in near proximity to where the cord 2 either exits from or enters in to the plugs 3,4.

2. Voltage-indicating cord 1, according to specification 1, characterized by the fact that two or more cords 1 where at least one cord is equipped with an illumination device 5',5" can be put together in combination with an outlet plug 3 and an extension plug 4 thereby creating a voltage-indicating extension cord.

3. Voltage-indicating cord 1, according to specification 1, characterized by the fact that the illumination device 5', 5" can even be fastened by another fastener than the relief clamp 19, preferably an extra relief clamp 19 in the same area 15', 15".

4. Voltage-indicating cord 1, according to specification 1, characterized by the fact that the illumination device 5', 5" can even be fastened to another part of the plug's 3,4 rear area 15', 15", preferably via a prefabricated fastener.

5. Voltage-indicating cord, according to specification 1-4, characterized by the fact that the illumination device 5',5" spreads its light through the plug's 3,4 cover 14, preferably via openings 8 in the cover 14, in close proximity to, against or within the opening 8 in the cover's 14 back wall 6 indicating that voltage exists.

6. Voltage-indicating cord, according to specification 1-5, characterized by the fact that the illumination device 5', 5" placed in the opening 8 in the plug's 3,4 cover's 14 back wall 6 permits some part of the illumination device 5',5" to be visually viewed within the opening 8 or somewhat outside the openingβ.