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Title:
HERMETICALLY SEALED GRAVE LIGHT WITH BATTERIES AND WITH WINKING LEDs INCORPORATED IN A PARAFFIN WAX BODY CONTAINING CONTACTS ENCLOSED UNDER THE LID
Document Type and Number:
WIPO Patent Application WO/2007/129346
Kind Code:
A1
Abstract:
A description is given of a hermetic lighting device for use preferably as a grave light, but also for signaling purposes on roads out in the open. The device comprises a cylindrical body (5) of paraffin wax placed inside a transparent container (2) of red plastic that adheres to the body it contains, said body having a stable base (3) and a lateral surface that emits a winking light from a LED (11,12) inside the body. One high-luminosity winking LED is used or else two LEDs placed parallel. In the manufacturing process the feed batteries (13,14) and the LED are placed inside an axial blind cavity (6) formed during solidification of the wax inside a mould. Before filling the cavity with the melted wax, two contacts (7, 8, 15a, 15b) are brought onto the outside and the wax is then left to cool. A metal lid (4es, 4in, 4sc,4ln) is pressed against the rim (2c) of the plastic container so that it presses against the electric contacts thereby closing the circuit for lighting up the LED

Inventors:
ROVEDA, Ivano (Via Napoli 49, Legnano, I-20025, IT)
Application Number:
IT2006/000413
Publication Date:
November 15, 2007
Filing Date:
June 01, 2006
Export Citation:
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Assignee:
ROVEDA, Ivano (Via Napoli 49, Legnano, I-20025, IT)
International Classes:
F21S4/00; F21S9/02; F21V23/04; F21Y101/02
Foreign References:
US20050207171A12005-09-22
GB2384850A2003-08-06
DE202005008904U12005-10-13
US20030035291A12003-02-20
US6616308B22003-09-09
Attorney, Agent or Firm:
MOCCHETTI, Ilio (Brevetti Dott. Ing. Digiovanni Schmiedt Srl, Via Aldrovandi 7, Milano, I-20129, IT)
Download PDF:
Claims:
CLAIMS

1. Lighting device comprising a body (5) with a low melting point able to diffuse light, of paraffin wax for example, having a stable supporting base (3), a lateral surface, an upper face, a cavity (6) for housing at least one winking LED (11, 12) of high luminosity, electrically connected to one or more feed batteries (13, 14) placed inside the cavity (6), characterized by the fact that it also comprises:

- a container permeable to light (2) to hold said diffusing body (5);

- at least two electric contacts (7, 8, 15a, 15b) for lighting the LED, external to the cavity (6) fixed onto the rim (2c) of the container (2) or else onto said upper face of the diffusing body (5);

- filling material in the diffusing body (5) re-solidified inside the cavity (6) with its contents (11, 12, 13, 14);

- a metal, or metalled, Hd (4ES, 4IN, 4SC, 4LN) with closing means that fit to the rim (2c) of the container (2) to a sufficient depth to close over the electric contacts (7, 8, 15a, 15b, 17a, 17b).

2. Lighting device as in claim 1, characterized by the fact that said lid (4ES) closes externally over said container (2).

3. Lighting device as in claim 1, characterized by the fact that said lid (4IN, 4LN) closes on the inside of said container (2).

4. Lighting device as in any one of the claims from 1 to 3, characterized by the fact that said closing means consist of a variation of the extension of the Hd in relation to the rim (2c) of the container (2) such as to cause elastic distortion of the materials that come together when the Hd is put on, exerting pressure in a direction perpendicular to said upper face of said body (5).

5. Lighting device as in claim 3, characterized by the fact that the lid (4SC) is hollow having a base and a lateral wall (4c) perpendicular to the base, comprising at least one groove (4b) on the inner side into which a dual rib (2b) fits, said rib being formed on the outer side of the rim (2c) of the container 2, and/or vice versa.

6. Lighting device as in claim 2, characterised by the fact that said lid (4SC) is cylindrical in shape and screws onto the rim (2c) of said container (2).

7. Lighting device as in any one of the claims from 1 to 6, characterized by the fact that said LED winks autonomously as soon as a working voltage is applied.

8. Lighting device as in any one of the claims from 1 to 7, characterized by the fact that it comprises a second LED placed parallel to the first that winks independently in relation to the first LED. 9. Lighting device as in claim 2, characterized by the fact that said electric contacts consist of two rivets (7, 8) mounted on the rim (2c) of said container (2).

10. Lighting device as in claim 3, characterized by the fact that said electric contacts consist of two small metal plates (15a, 15b) that partially , emerge from the upper face of said diffusing body (5).

11. Lighting device as in claim 3, characterized by the fact that said electric contacts are two metal blades bent to a V (17a, 17b) that partially

. emerge from the upper face of said diffusing body (5).

12. Lighting device as in any one of the claims from 1 to 11, characterized by the fact that it is a grave light.

13. Lighting device as in any one of the claims from 1 to 11, characterized by the fact that it is a lamp for signalling purposes on roads.

14. Method of production of the lighting device in claim 1, characterized by the factthat it includes the stages of: - pouring material of a low melting point into a mould and leaving it to cool to obtain a body (5) able to diffuse light and having a cavity (6) in communication with the outside; . - introducing said solid body (5) formed by cooling inside a container (2) permeable to light, that might be the mould itself; - introducing into the cavity (6) an assembly consisting of at least one LED (11, 12) connected to one or more electric batteries (13, 14);

- placing electric contacts for lighting the LED (7, 8, 15 a, 15b, 17a, 17b) at the upper end of the device outside the cavity (6);

- filling up the cavity (6) in said light-diffusing body with extra melted material and waiting for it to cool; - pressing a metal, or metalled, lid (4ES 3 4IN, 4SC, 4LN) onto said container (2) against said electric contacts (7, 8, 15a, 15b, 17a, 17b). 1-5. The method in claim 14, characterized by the fact that the electric contacts (7, 8) are fixed to the upper rim (2c) of said container (2) before the cavity (6) is filled. 16. The method in claim 14, characterized by the fact that the electric contacts (15a, 15b, 17a, 17b) are anchored to the material present in said container (2) and emerge from the upper face of the body (5). 17. The method in claim 16, characterized by the fact that the ele,ctric contacts (17a, 17b) are welded directly to a contact surface of one of the feed batteries (13, 14).

Description:

HERMETICALLY SEALED GRAVE LIGHT

Field of application of the invention

The present invention relates to lighting devices similar to candles having an internal source of light, and more precisely to a hermetically sealed light for graves with batteries and with winking Light Emitting Diodes (LED) comprised in a paraffin wax body provided with contacts enclosed under the lid. Review of the known art The US patent 6,616,308 B2 describes a device imitating a candle by means of a LED placed inside a translucent cylindrical body made of paraffin wax or plastic. The first claim reads as follows: an ornamental lighting device comprising: a) a body diffusing the light having permanent exterior surfaces including an upper surface the central section of which is depressed to seem as if reduced by melting; b) a cavity inside the body from which the light is diffused; c) a LED of high luminosity placed within the cavity to illuminate, from below, the underneath of the central depressed section making it more brilliant than the other surfaces of the body diffusing the light. Figure 1 shows a candle in the form of a grave light having a LED 24 inside a narrow central cavity 26 open at the bottom and terminating uppermost below a depression 20 in the upper face 16. The LED is connected to two electric wires 28 that emerge from the cavity 26 and

connect to -an external feeder 30 fitted with a switch 32. Figure 2 shows another version without an external feeder but having batteries 40, 42, housed within a lighting module 36 placed in a more amply sized central cavity 38 open at the bottom of the candle. The module 36 is surmounted by the LED 24 and inside, in addition to the batteries, there is also an electronic device for operating the LED able to imitate the flicker of a candle flame.

Problems encountered by the known art The primary purpose of the devices described in the US patent 6,616,308 B2 referred to above, was to imitate a candle as closely as possible, including a flickering flame, but producing an aesthetic effect that differs from previous imitations fitted with an external lamp, being created by the light diffused through the paraffin wax body. The declared purpose required optic exposure of the upper surface of the candle and resorted to a particular type of electronic circuit for operating the LED. These technical requirements do, however, involve limitations to the life of the device and to the possible type of use, as well as higher costs and greater bulk; take, for example, the use

of the device as seen in Figure 1, as a grave light out in the open and therefore exposed to rain and hard weather. In view of the poor degree of impermeability of the device illustrated, it pould not be used in that way unless it were placed inside some form of lamp-holding means in order to avoid entry of water or damp through the cavity open at the bottom as this would risk short-circuiting the LED. The external feeder would also have to be hermetic, in which case the extra cost of waterproofing both the device and the feeder, as well as the poor aesthetic effect of the feeder close to the lamp-holding means, might well discourage potential clients from purchasing it for their graves.

The version seen in Figure 2 also appears to be open at the bottom so that rain and damp could enter and reach the LED in that model too. The position of the switch is not clear so that it might not be proof against rain water unless lighting the device were radio-controlled. The module 36 is clearly somewhat bulky, this being due to inclusion of the LED operating

circuit and of its large batteries, the electronic control card and the high- luminosity LED needed to feed the device for a reasonable length of time. Both these products are less efficient in lateral diffusion of light by having to concentrate diffusion upwards. In both cases the light in fact passes through a thinner layer of paraffin wax in the upward direction than it does laterally or downwards. • Purpose of the invention

The purpose of the present invention is therefore to overcome the above drawbacks and to offer a device that diffuses light through a paraffin-wax type of translucent body, preferably for use in graveyards or for road signals, fully able to withstand weathering that might affect its use in the open, operationally independent even though comprising a high-luminosity LED, while also being inexpensive to manufacture. Summary of the invention's advantages To achieve ' these purposes, subject of the present invention is a device for illumination comprising a light diffusing body made of a type of paraffin wax with a low melting point, said body having a stable base, a lateral surface, an upper face and an internal cavity in which to insert at least one

' winking (or blinking) high-luminosity LED, electrically connected to one or more feed batteries; further comprising a container permeable to light to hold said diffusing body, it least two electric contacts, placed outside the cavity, for lighting the LED, fixed to the rim of the container or else to the upper face of the diffusing body, filling material for the diffusing body, resolidified inside the cavity with its contents, a metal, or metalled, lid the rim of which fits sufficiently low down to close the electric contacts as described in Claim 1.

Further advantageous characteristics are described in the dependant claims; for example, the electric contacts can be the wires themselves, but are preferably in the form of rivets introduced through holes in the wall of the upper edge of the plastic container and cold riveted, or else two small plates that project from the upper face of the paraffin wax body. These plates may include a toothed peduncle to fix them more firmly to the wax. The contacts

can be in the form of metal blades bent to a V and therefore elastic, that emerge from the wax-filled cavity for most of their length, with the other end inside the wax and welded onto one surface of a battery. Finally, a button switch can be made to project slightly from the upper face of the wax body.

For each form of the contacts described above, the electric circuit between them is closed by pressure from the metal Hd itself. The lid can fit on externally to the light's plastic container or inside it. In the first case it will have a smooth rim or at least one perimetric groove and/or border or rib; the lid with the smooth rim is the simpler type of the two, while in the second case it is more reliable because it fits between the groove in the lid and the corresponding rib on the plastic container, and/or vice versa. The above lids applied by pressure are used for any shape, for example, cylindrical, parallelepiped or some other. In the more usual cylindrical shape it may be advisable to have a lid that screws onto the plastic container by means of a pseudo-thread.

Use of a diode that itself is able to produce a winking effect, without any control circuit, means a longer life for the batteries and lower manufacturing costs. Where two winking diodes are used, since their wink is not synchronised, an effect somewhat similar to that of a flickering flame can be achieved.

Another subject of the invention is a method used to manufacture the lighting device described above, comprising the following steps:

- pouring a quantity of material having a low melting point into a mould and allowing it to cool to form a body capable of diffusing light, said body having a cavity in communication with the outside; placing the cooled solid body in a container permeable to light, for which purpose the mould itself could be used;

- placing at least one LED, wired to one or more electric batteries, inside the cavity;

- placing electric contacts for lighting the LED in the upper part of the device outside the cavity;

- filling the cavity with melted material of said light diffusing body and waiting for it to cool;

- placing a tight-fitting metal lid onto the container over the electric contacts. Ignition of the grave light can be temporarily prevented by covering the electric contact with a strip of paper or a removable film of insulating . material.

Further advantageous characteristics are described in the dependent claims on method. For example, electric contacts can be applied in different ways. According to one mode of executing the method applicable to contacts in the form of rivets, these are applied to the upper rim of the plastic container before filling the cavity with paraffin wax. The electric wires are partially wound onto the rivets before being fixed. According to a second mode of executing the method applicable to contacts in the form of small metal plates welded to the wires of the electric circuit, these are first extracted from the cavity and then partially inserted into the cooling wax so that they will emerge at the upper face. According to a third mode of executing the method applicable to contacts in the form of metal blades bent to a V, after the batteries and LEDs have been placed inside the cavity, due to the reciprocal dimensions of batteries and cavity, the bent blades emerge from the cavity for most of their length; it is

' then sufficient to fill the cavity with melted wax and leave it to cool.

This brief description of the invented device (and method of production) shows that it can simultaneously achieve all the stated aims. As far as concerns a hermetic seal, rain water and damp can in no way penetrate inside the paraffin wax body, not even if a strong gust of wind were to blow it over. This wax possesses excellent water-repellent and electrical insulation properties, the melted and re-solidified wax forms a single mass with that already existing. The lid not only closes the contacts but also . protects them from corrosion; being opaque, it unfortunately prevents the light from being seen from above, but this disadvantage 's more than compensated by the greater amount of luminosity at the sides. On the other

hand the main purpose of this luminous device is not to be a complete imitation of a conventional type of light created by combustion, but to provide a reasonable compromise in order to achieve the stated purposes and advantages. The bright light shining from the lateral surfaces shows up well even on the sunniest days when it is hard to discern any light produced by the ordinary type of electrical grave light. For decorative purposes, a crown can be applied to the lid with open-work crosses or other suitable motifs. The ordinary stylus 1.5V type AA batteries last up to three months, the torch type much longer. When the batteries are exhausted, the wax and diodes

can be recovered and used to make other : devices, the batteries themselves disposed of. The shopkeeper might encourage recycling by taking back the exhausted parts and allowing a small discount on new purchases.

It should be emphasised that the hermetic seal and strong laterally-emitted light possessed by this device make it suitable for purposes other than that of a grave light, such as a signal lamp on roads where special care must be taken to avoid possible danger, for example where road work is in progress. Short description of the drawings Further purposes and advantages of the present invention will be made clear from the detailed description that follows of an example actually produced and from the attached drawings provided as illustrations in no way limited to these, in which: figures 1 and 2, already described, show two views in perspective, partly cut open, of two alternative versions of an electrical device made to imitate a candle, in accordance with the art presently known;

- figures 3, 4 and 5 show in perspective, an electrical lighting device produced in accordance with the present invention, with three different types of lids;

- figure 6 illustrates a perspective view of the grave light in Figure 5 with the lid raised and traced lines indicating the position of an axial cavity;

- Figures 7, 8 and 9 show a section of the upper portion of the lights illustrated respectively in figures 3, 4 and 5, along a longitudinal plane

that passes through the contacts;

- figure 10 gives a perspective view of the grave light in Figure 6 in a final stage of production with traced lines marking some internal parts;

- figure 11 gives a partial perspective view of the light in Figure 5 in a final stage of production, produced according to an alternative version of the ' invention; ■ figure 12 shows a longitudinal section along a median plane that passes through the contacts of an electrical illuminating device in accordance with another version the present invention.

Detailed description of some preferred forms of realizing the invention As a general rule the objects shown in the figures are not actually on a real scale. Referring to Figure 3, an illuminating device 1 is shown comprising a cylindrical container 2 resting on a base 3, closed by a metal lid 4ES. Placed inside the container 2 is a light (not seen in the figure) of the same shape as the container 2. The lid 4ES has a smooth rim that encloses a short section of the cylindrical surface of the container 2. The cylindrical container 2 is made of thin plastic material, permeable to light, adhering to the paraffin wax body of the grave light, except on the upper surface, and is preferably coloured red. It is best to use paraffin wax to make the device, but this is riot essential; there are other materials having a low melting point that are also suitable. One or more LEDs can be incorporated inside the cylindrical wax body, their presence, when the device is lit, being indicated by the arrows on the drawing put there to represent light diffused through the lateral surface of the container 2.

Figure 4 shows a lighting device that only differs from the preceding one in that the Hd 4IN fits inside the plastic container 2. The Hd 4TN has a smooth circular rib in contact with the internal cylindrical surface of the container 2, and an edge that, extends slightly outward from it.

Figure 5 shows a lighting device that differs from the preceding ones having a differently designed lid 4SC and because it has a wider base 3 similar to a

pedestal. The lid 4SC differs from Hd 4ES in Figure 3 having a deep

undulating rim that includes an external groove 4a above a projecting rib 4b; these latter can also be present singly, or can form a short thread for screwing onto the cylindrical body 2. As the thickness of the lid remains unvaried, the internal rim also contains the groove and rib in the reversed order.

Figure 6 shows the lighting device seen in Figure 5 when one processing stage has been completed. Seen inside the plastic container 2, open at the top, is a circular crown corresponding to the upper face of a cylindrical body 5 grooved by a cylindrical blind cavity 6 placed axially starting from the upper face ' and terminating at a fixed distance from the base 3. The cylindrical body 5 is the one that will become the paraffin wax grave light when complete. Depth and width of the cavity 6 are such as to permit entry of one or more feed batteries and of one or more light emitting diodes ' known as LEDs (shown later), and of course the necessary wiring. Towards . the upper end of the plastic container 2 is a circular groove 2a above which is a rib 2b, set at a certain distance from the open edge at the top. The groove 2a and the rib 2b are respectively complementary to the rib and groove present on the inside of the lid 4SC (Figure 5) where they fit into a rib 4a and groove 4b. Between the upper edge of the container 2 and the groove 2a is a circular rim 2c onto which are fixed two circular electric contacts 7 and 8 respectively connected to two electric wires 9 and 10. The position of the contacts 7 and 8 along the circumference is unimportant; these contacts are two rivets fitted into holes in the wall of the circular rim 2c and riveted when cold. The bare electric wires 9 and 10 are partly wound round the contacts 7 and 8 and fixed in place when these latter are riveted. When in position the contacts project slightly from the outer rim 2c and this makes for greater stability of electrical contact. Figure 7 gives a detailed view of the electric contacts 7 and 8 when the Hd 4ES, visible in Figure 3, is used. It will be seen that the edge of the plastic container 2 rises higher than the level of the paraffin wax 5 to allow space for fitting the two rivets 7 and 8 in contact with the inner wall of the lid

4ES. The internal diameter of the Hd 4ES is such that some slight pressure is needed to place it over the container 2 , the effect being to render the rivets 7 and 8 more stable.

Figure 8 gives a detailed view of the electric contacts 7 and 8 when use is made of the lid 4IN seen in Figure 4. It will be seen that the rim of the plastic container 2 rises higher than the level of the paraffin wax 5 to allow space for placing the two rivets, 7 and 8, in contact with the outer wall of the lid 4IN. The external diameter of the lid 4IN is such as to make it necessary to apply a slight amount of pressure when fitting it inside the container 2, its position then ensuring stability for the rivets 7 and 8.

Figure 9 gives a detailed view of the electric contacts 7and 8 when use is made of the lid 4SC seen in Figure 5. It will be seen that the rim of the plastic container 2 rises above the level of the paraffin wax 5 to allow space for placing the two rivets 7 and 8 in contact with the internal wall of the lid 4SC. The figure clearly shows how the complementary ribs and grooves, present in the lid 4SC and in the plastic container 2, fit into each other. The internal diameter of the lid 4SC is such that slight pressure is required to place it on the container 2 in such a way that stable contact is maintained with the rivets 7 and 8. Figure 10 shows the lighting device in figure 6 as it appears on completing a final stage of processing that precedes application of the lid 4SC. Inside the cylindrical paraffin wax body 5 two LEDs 11 and 12 can be seen, connected in parallel, and two 1.5V stylus batteries 13 and 14, type AA connected in series and to the parallel of the LEDs 11 and 12. To put it more precisely, one pole of the two series-connected batteries is connected to contact 7, and the other pole is connected to one end of the parallel of diodes 11 and 12 by the wire 9, while the other end of the parallel of the diodes is connected to contact 8 through wire 10. The high-luminosity diodes are of the winking type which means they can turn on and off autonomously without the need for an intermittent lighting control. These diodes are easily available on the market and give excellent results with a feed of 3 V. At this voltage they can wink about twice a second; at a lower voltage both light emitted and

winking frequency are reduced. The colour of the light emitted by the diode can be. chosen among several options,, preferably solar white because the ultimate colour that will be seen is the traditional red of the plastic container 2. The figure does not show the limits to the cavity 6 because at this stage of the process the cavity has already been filled and no longer exists, the components having been incorporated in the wax.

The description of the contacts in the form of rivets and metal plates given on the grave light in Figure 5 is immediately extended to products made as shown in Figures 3 and 4. Figure 11 shows an alternative version of the grave light seen in Figure 5 as it appears when completed prior to fitting on the lid 4SC. The difference consists in a different kind of contacts which are now two small metal bars or plates 15a and 15b welded to their respective wires 9 and 10. If the contacts are bars they can comprise a peduncle pleated to help hold the wax. As the figure shows, the wax 5 fills the plastic container 2 up to the brim and the metal bars 15a and 15b emerge from the level surface. When pressed onto the body of the grave light, the metal lid 4SC makes contact with the two bars so closing the electric circuit. If requiring to use the lid 4IN the added wax should not flow out from the cavity 6. Figure 12 shows a further version of the invented electric lighting device which to some extent is an improvement on the version shown in Figure 11. The arrangement of the batteries 13 and 14 set side by side in the wax 5 seen in the figure is made possible by the presence of a cavity (by now filled up), depth of which is little more than the length of the batteries. Welded to the contact surfaces (of opposite poles) of the two batteries so placed, are two first ends of two metal blades, 17a and 17b, bent to a V to act as springs. The two blades emerge from the wax 5 for about two thirds of their length without touching each other. The other two contact surfaces of the batteries 13 and 14 are directly connected to the two terminals of LEDs 11 and 12 which are therefore parallel. A metal, or metalled, lid 4LN, consisting of a hollow cylindrical body with a flat bottom, when fitted on and into the plastic container 2 exerts a certain degree of downward

pressure, pressing against the metal blades 17a and 17b and, in doing so, closes the electric circuit that feeds the LEDs. Stability of the state of closure of electric contacts 17a and 17b is ensured over time by pressure from the rim of the lid 4LN against the, internal lateral surface of the plastic container 2, said pressure being generated by elastic distortion of the materials in contact with one another, in turn caused by pressure exerted when the lid is put on. Closure of the electric circuit is made still more reliable by the slight pressure against the bottom of the lid 4LN exerted by the spring-like contacting blades 17a and . 17b. Another version compared with the one seen in Figure 12 is also possible by one or both of the bent blades 17a and 17b being long enough for their free ends to become superimposed. In that case the electric circuit could be closed by pressure from the lid only, without it necessarily having to be metal or metalled. The method used to produce the device illustrated in the preceding figures varies according to the type of contacts; a description will first be given to the method with rivets, valid for the three types of lid 4ES, 4IN and 4SC without any changes being necessary. It is advisable to start from making a conventional flame-type grave light, presuming that the maker has already formed the cylindrical axial cavity into which the components will be introduced. This can conveniently be done during the stage of pouring the liquid paraffin wax into the mould, all that is needed is to place inside the mould a solid cylinder in the position intended for the cavity 6 after the wax has cooled and the body 5 been removed. The hollow cylindrical body 5 will then be put into the container 2 whose height exceeds that of the body 5 by the whole of the rim 2c allowing sufficient space for the rivets 7 and 8. The container 2 itself could advantageously be used as a mould. The complete electric circuit is then assembled separately taking care to cut wires 9 and 10 to the right length for passing through the body 5 and reaching contacts 7 and 8. Having thus assembled the electric circuit, it is then placed in the cavity with the wires 9 and 10 emerging from the top. The rivets 7 and 8 are fitted into their respective holes previously made for them in the thickness of the rim 2c, and the bare ends of wires 9 and 10 are

wound each round its respective rivet which are then pressed down so that they entrap the wires. The wax is then melted separately and poured into the cavity till it reaches the level of the upper face of the cylindrical body 5. When using lids 4ES and 4SC it is possible, though inadvisable, to fill the container right up. It is then left to cool and the contacts 7 and 8 are temporarily isolated by covering them with a piece of thin plastic to be taken off at the time of lighting up the device, after which the pressure lid is put on. The method for applying contacts in the form of small metal bars or plates, 15a and 15b in Figure 11, differs at some points from the preceding one; this is due to the fact that the contacts are not mounted onto the container 2 but placed right inside the paraffin wax during the final cooling stage, or subsequently, causing local melting. In this case the complete circuit also comprises bars 15a and 15b welded to wires 9 and 10 kept outside the cavity 6 before it is filled. This version of the method can be used for all three types of Hd.

The method used for mounting the contacts in the form of metal blades, 17a and 17b Figure 12, is similar to the preceding one but simpler as the depth of the cavity is such that, when the two batteries 13 and 14 rest on the bottom, the, two blades 17a and 17b emerge for most of their length from the cavity and therefore do not need to have their positions adjusted during the final stage of cooling. .

Considering the description given for some preferred examples of how the device is produced, it is clear that a competent technician could make some alterations to it without thereby departing from the sphere of the invention. For example, lids 4ES, 4IN, 4SC and 4LN can be made of surfape-metalled plastic material in accordance with the most common techniques, namely: electroplating, brush or spray painting, immersion in a metallic solution, glueing of metal sheets, etc. The present invention therefore comprises all the forms of realization expressed in the following claims.