ES2314864T3 - SEALED PLUG FOR ELECTRICAL CONNECTION TO AN ELECTRIC CONDUCT. - Google Patents

Abstract

Leaktight plug for electrical connection to a bus duct (17) in which an insulating body (1) houses in a plurality of slots (2, 3, 4, 5) which are hermetically sealed over their entire length by an insulating sheet (10) a corresponding plurality of conducting bars (6, 7, 8, 9), comprising a supporting member (18) and a plug body (19) hinged to the supporting member to adopt a disconnected operating position and an electrically connected operating position, the supporting member (18) being provided with attachment means (39) which can be operated manually for attachment and detachment to/from the bus duct only if the plug body is in the disconnected operating position, the plug body being provided with contact clamps (25) which in the connected operating position enter into contact with the conducting bars (6, 7, 8, 9) after having perforated the insulating sheet (10), the contact clamps (25) being surrounded by a seal (26) which in the electrically connected operating position ensures a leaktight connection between the plug body and the bus duct.

Description

Waterproof plug for electrical connection to a electrical conduit

This invention relates to an electric plug waterproof for electrical connection to an electrical conduit, which is in itself tight.

It is known that members of prefabricated ducts, normally referred to as electrical conduits, for distribution of electrical energy inside buildings, particularly for use industrial or for offices, shops, shopping centers and similar, they consist of members of normalized lengths, by example of 1, 2, 3 meters that are intended to be connected at its ends to achieve the required longitudinal dimension for each specific application.

The electrical connections to power the Power user equipment can be made at any point to along its length.

These prefabricated members must satisfy Many requirements: in addition to the ability to drive high currents, on the order of tens of amps (usually 25 to 40 A), they must ensure maximum safety during the possible operation after installation, and, in many types of installation, such as the so-called "floating" under the ground of the facilities, or above false ceilings, and in all cases in which there is a risk of possible water seepage, they must be impervious to liquids, that is they must be waterproof.

Although the requirement for job security of the operator (or "finger test requirement") can be satisfied by relatively simple and economical means, such such as those described in the European Patent Application EP 1049227 by the same applicant, the requirements for the system be tight have been satisfied so far by means of particularly complex and expensive structures that did so much the installation as the subsequent adaptation of the system, as well as the creation of new outlets, withdrawal of outlets pre-existing and system extension, particularly difficult and laborious.

In the European Patent Application EP 05425579.9, recently submitted by the applicant, is proposed and describes a prefabricated duct member that overcomes these inconveniences and provides an extremely simple structure which can be economically manufactured in large volumes and satisfies the aforementioned requirements.

With this type of prefabricated member, it is nevertheless necessary to provide watertight devices to electrical sockets through which the electrical equipment at any point along the length of the electrical conduit

The plugs that can be connected electrically at any point along the length of a electrical conduit are known for example from the document EP0015356, but these plugs are not waterproof, nor is it the electrical conduit

The document US-A-3771103 describes a:

- plug (see Figure 6) for connection electrical to an electrical conduit (see Figure 12), in which The electrical conduit which is an insulating body (1) houses a plurality of conductors (15) in grooves (3) sealed by a sheet of insulating material (54, see column 5, lines 35-40),

- a support member (30,31) to support and anchor (with 26, see Figure 5) to said electrical conduit,

- a body (30, 31) of plugs from which it emerges a plurality of contact pliers (28), said anchor being anchored body to said electrical conduit through said member of support, and, in order to take the electricity connected to the operating position, the contact pliers pierce said insulating sheet (see Figure 13) and establish contact electrical with said conductors. ''

Conversely, devices of waterproof electrical connection that can be connected to conduits electric watertight only in predetermined positions at along them, provided for this purpose.

However, they can only be done connections through laborious operations that use proper tools and generally require the system to be disconnected.

The disconnection of the electrical conduit and the property restoration at the point where a plug is Dismantled are also laborious.

This invention overcomes these problems and provides a waterproof electrical connection plug that can be inserted at any point along the length of a electrical conduit of the aforementioned type, by means of a simple two-stage operation, fixing and electrical connection, respectively, without the need for any tools and without it is necessary to disconnect the system.

Both, the insert operation and the Withdrawal can be carried out under conditions of maximum safety,  without any possibility of accidental contact between the Operator and parts with current.

The modular plug structure means also that its components can be used to make a diversity of plugs capable of satisfying the maximum variety of user needs, such as connection to only one or many phases of a three-phase system and / or the incorporation of protection fuses inside the plug.

According to the invention, these results are achieved through a plug structure as described in the claims that are added.

The characteristics and advantages of the invention they will be better evidenced from the following description of a preferred embodiment and its variants provided with reference to the drawings that are added in which:

- Figure 1 is a sectional view cross section of a prefabricated duct member in which they are designed the connectors, according to this invention, to be connected,

- Figure 2 shows schematically in a side view a sealed plug, according to this invention, mounted over the electrical conduit in an operating position disconnected,

- Figure 3 shows schematically, in a side view of the plug in Figure 2 in the position of electrically connected operation,

- Figure 4 is a perspective view in exploded view of a preferred embodiment of the device that fix the plug, in the two operating positions in the Previous figures,

- Figure 5 is a cross section to through the plug in Figure 3 according to BB view in that figure,

- Figure 6 is a cross section of the plug in Figure 3 according to the CC view in that Figure,

- Figure 7 is a detail view, in perspective, exploded view of the various components of the plug in the preceding figures,

- Figure 8 is a perspective view, in neat, and expanded exploded view of a preferred embodiment of the electrical connection clamp with the electrical conduit for the plug of the preceding Figures,

- Figure 9 is an enlarged view in perspective of a box container for the clamp in Figure 8,

- Figure 10 is an exploded view ordered, in cross section, according to the DD view in Figure 9, of the box in Figure 9 and the components housed in the same.

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For a better understanding of the invention is first necessary to provide a brief description of the member of prefabricated conduit (hereinafter simply called conduit or  electrical conduit).

For more detailed information regarding duct and to the preferred embodiment thereof, reference is made to European Patent Application EP 05425579.9 already cited.

Figure 1 shows a cross section transverse of an electrical conduit. This comprises a body straight extruded 1 plastic material (PVC and similar) insulator in which a plurality of grooves are formed, for example four, 2, 3, 4, 5, in each of which a bar is housed vertical driving, 6, 7, 8, 9 respectively, extruded in conjunction with body 1.

Advantageously, bars 6-9 they are obtained by bending a copper or aluminum plate so that an inverted T-shaped cross section is produced with lower branches incorporated into the body 1.

At the top, with reference to the view in Figure 1, the slots are closed by a sheet 10 of insulating plastic and that can be perforated throughout the entire duct length, so that they are liquid tight to except at the ends of the duct.

Although not essential, a protection for the sheet 10 comprising a cover 11 of plastic that connects to arms 12, 13 of body 1 and is easily removable to allow a connection to be made electric with bars 6-9 at any point at along the length of the duct perforating the sheet 10.

In the base body 1, a shell is included 14 of metal obtained by folding a metal sheet with arms 15, 16 folded inwards and connected tightly to the corresponding arms of the body 1.

Conveniently, in addition to providing the function of stiffening and protecting the body 1, the shell 14 acts also as a ground conductor.

To conclude the description of the conduit in the Figure 1 must take into account that the section profile transverse is asymmetric with respect to a vertical average plane A-A

In particular, it must be taken into account that two arms 15, 16 of the closure are of different horizontal length, greater in the case of arm 15 and less in the case of arm 16.

This provision serves to "polarize" mechanically the duct continuously throughout its length, and guarantees that the electrical connectors, if they end up in connectors intermediate, they are connected in the conduit unequivocally concrete.

The same effect can be achieved through a closure 14 in which the arms 15, 16 are of the same length horizontal but are located at different heights with respect to the closing base or providing arms 12, 13 of different thicknesses for body 1, as shown particularly in the Figure 1, in which the arm 13 is thicker than the arm 12.

Obviously, it is possible and can be It is convenient to combine the different provisions.

Next, an embodiment will be considered preferred of a waterproof plug for electrical connection to electrical conduit already described, with reference to Figures 2 and 3.

Figure 2 shows schematically, in the side view and in partial cross section, a sealed plug constructed according to this invention, mounted in a conduit 17 of the type already described, in which the lateral arm 13 and the metal closure side 14.

The plug essentially comprises a member 18 support and connection, which is injection molded from a material plastic such as PVC and the like, and a plug body 19 that it comprises a base 20 and a removable cover 21, molded of new insulating plastic material and connected together through an intermediate seal, which is not visible, which guarantees that The connection is leakproof.

Conveniently the shutter can be obtained together with base 20 by means of a procedure of set molding.

The body, which is generally elongated in the direction of the electrical conduit, is articulated at one end 221 (on the left in Figure 2) on a pin 22 composed of a piece with the support member 18 to adopt a position electrically disconnected as illustrated in Figure 2 and a electrically connected position as illustrated in Figure 3.

The body 19 is provided at its end 221 of a sealed, perforable, conventional opening 23 for entry of a cable 24 coated, flexible, multipolar.

Inside the body there are connecting members electrical, not visible, to connect the various conductors of the multipolar cable 24, apart from the ground conductor, to each of a plurality of contact pliers 25 protruding from the base 20 through convenient openings that are not waterproof.

Around these openings, which are located within a restricted area of the base, referred to here as ahead of the window, there is a molded mass 26 of elastic material (synthetic rubber) that acts as a tight seal.

The earth conductor of the electric cable multipolar is electrically connected inside body 19 to a metal contact sheet 27 protruding down from the base 20 to come into contact already with the side of the closure 14 of metal in the position illustrated in Figure 2.

The opening from which the contact sheet protruding is provided with a tight seal, which cannot be seen in Figure 2, obtained as an integral art of closure waterproof between the base and the cover, through it whole molding procedure.

At the opposite end to that in which the opening 23 is located, and outside the coupling seal between the base and the cover, the cover extends to form a housing 28, open at the top and bottom, for a locking device comprising an elastic tongue 29 that is integral with the member 18 of
support.

Accommodation 28 is closed on the front by a shield 30, which is integral with the sides of the accommodation.

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In the upper and lower parts the shielding forms two teeth 31, 32 of detention (which are preferably displaced vertically to prevent produce lower cuts that will complicate the operations of molded) which are applied in a groove 33 formed in a intermediate position of the elastic tongue 29.

In Figure 2 the stop tooth 32 bottom is applied in slot 33 and stably maintains the plug in the operating position disconnected.

Exerting convenient manual pressure on the end of the tongue 29 towards the plug body, the tooth 32 can be decoupled from slot 33.

The plug body can then be pushed, again manually, towards the support member 18 of so that the upper tooth 31 is applied by elastic jump in the slot 33, as illustrated in Figure 3, and holds the body immobilized against the support member in a position in which the contact pliers 25 (Figure 2) penetrate the grooves inside of the electrical conduit after perforating the insulating sheet 10 (Figure 1) of the electrical conduit and comes into contact with the bars 6, 7, 8, 9, guaranteeing the electrical connection.

At the same time, shutter 26 (Figure 2) that surrounds the tweezers 25 comes into close contact with the blade 10 of electrical conduit insulation, ensuring that the connection is watertight

This connected operating position electrically illustrated in effect in Figure 3.

To return the plug body to the electrically disconnected operating position is enough to push the tongue 29 towards the plug body, decoupling tooth 31 from groove 33, and rotating the body of the plug around the joint 22 until the tooth 32 be applied with slot 33, ensuring a disconnected position stable.

The arrangement of teeth 31, 32 and the groove 33 illustrated in Figures 2 and 3 is purely by way of example and it is illustrated in this way exclusively for clarity and simplicity of the graphic representation: it is evident that the papal of the Groove and tooth, 31 and 32, can be exchanged.

In practice, as illustrated in the view in exploded view in partial perspective in Figure 4 is it is preferable to configure two pairs of recesses 43, 44 and 44, 45 on the opposite sides of tongue 29, properly stiffened by a nerve 47, and provide the shield 30, which it makes flexible by means of two slots 48, 49 that separate this from sides of housing 28 except at the top, with both side arms 50, 51 provided with teeth 52, 53 that are apply in one or the other of the pairs of recesses 43, 44 and 44, 45.

When pressure is exerted on the bottom of shield 30 in the direction indicated by arrow 54, the teeth 52, 53 disengage from the recesses and allow placement the plug body in the electrically disconnected position or The electrically connected position.

Tab 29, advantageously, is provided at the top with two lateral projections 55, 56 that at interfere with the arms 50, 51 of the shield 30 prevent the plug body rotate more, with respect to the member 18 of support, beyond the disconnected position.

We will now consider member 18 of bracket and complete plug unit in greater detail with joint reference to Figure 3 and the cross section in the Figure 5 illustrating the plug in the operating position in which is electrically connected to the electrical conduit.

For simplicity and clarity, only Essential members are illustrated in Figure 5, the components internal plug bodies are illustrated in greater detail in the exploded perspective view of Figure 7.

The support member 18 comprises a frame, generically in the shape of a saddle, which rests above the electrical conduit, riding on it.

Within one of the sides 34 of the support (Figure 5) a series of teeth 35 that engage under arm 12 at a distance from the support plane (consisting of sheet 10) which is equal to the thickness of arm 12 (the smallest thickness) of the electrical conduit.

It is impossible to hook these teeth on the opposite arm 13 of the electrical conduit due to the greater thickness of the latter.

The support member is then polarized mechanically to ensure a unique position in which it is immobilized on the electrical conduit.

In addition to this, for added security and for middle of the same mechanical polarization effect, the opposite side of the support member extends downward in the form of two arms 37, 38 (Figure 3) that extend along the metal compartment 14 when the support member is in the correct position and interferes with the protruding side of it, preventing the support on the electrical conduit if the positioning is incorrect.

For permanent fixation to the duct electric the support member is provided with a first command lever 39, fully configured with the member of support, on the same side on which the two arms 37, 38 they are present. The lever is articulated in the support member through a pair of relatively flexible fasteners 41 (Figure 5).

The lever ends at the bottom in a tooth 40 of application that applies the arm 13 of the electrical conduit.

The lever 39 drive for the fixation and release, which requires pressure to be exerted on the top of the lever in the direction indicated by arrow F (Figure 5), is allowed only if the body of the plug is located in the operating position of electrically disconnected illustrated in Figure 2.

Otherwise, a detention 42, which stands out on the side of the cover 21, also illustrated in Figure 2, prevents The rotation of the lever.

It is therefore evident that to fix the plug to the electrical conduit it is necessary to first place the plug body and the corresponding bracket in the position of relative disconnection, if this is not already in that position, and then push the lever up so that it separates the teeth 40 from its resting position and adjust the support member 18 on the electrical conduit (in a unique arrangement determined by mechanical polarization), applying tooth 35 under the arm 12, and then releasing lever 39.

Fixing can also be done by quick connection means, exerting the appropriate pressure towards the electrical conduit

The operation can be performed with the maximum safety because in this phase the tweezers 25 (Figure 2) do not enter contact with the busbars.

Acting then on the shielding (in the box illustrated in Figure 4) or the tongue 29 (in the box illustrated in Figures 2 and 3) it is then possible to push the plug body inside the connected position electrically

It is clear that to disconnect the plug from the electrical conduit the described operations must be performed In reverse order. First the plug must be placed in the disconnection position by operating on the tongue 29 or the protection 30.

It is essential then to act on lever 39 to release the teeth 40 from the electrical conduit.

At this point the unit of the element of plug / holder can be removed from the electrical conduit under maximum security conditions.

The cross section in Figure 5 shows also in detail a preferred embodiment of the connection between the cover 21 and the base 20 of the plug body.

The base 20, housed between two sides of the member 18 support, extends up to form a piece molded 57 with a top housing for a shutter 58 jointly molded that is, tightly compressed against leaks through a peripheral nerve of the cover 21, which also extends to form a guiding skirt 59 that surrounds all base 20 and all support member 19 outside the area in which  the support member 18 extends to form the lever 39.

Completely similar is the cross section in Figure 6, on the ground contact sheet 27 (Figure 2), which Significantly shows contact sheet 27 projecting from base 20 with a sealed outlet opening provided by sealing 58 on one side of the sheet and a second seal 60 formed by a joint molding together with the first on the opposite side.

Together with the contact sheet 27 the base 20 is extends down into an appendix 61 that protects the blade and when the plug unit is installed on the conduit electric pushes the blade putting it in contact with the side of the metal enclosure 14 of the electrical conduit.

Appendix 61 and contact sheet 27 pass freely through an opening in the support member 18 and they are housed in a suitable recess in the arm 37 of the member of support.

Inside the sealed body the contact sheet 27 is folded again to form a connection terminal 62 electric with an opening 63 for the passage of a screw squeeze in.

In addition to the parts already described, shown in greater detail, the exploded perspective view arranged in Figure 7 shows the various components housed in the body of the plug.

With reference to support member 18 the two arms 37, 38 and lever 39 on one side of this, and the set of application of teeth 35 on the inside of opposite side 34, They will be observed.

One of the pins 22 that form a part of the support member, on which the base 20, and the locking device comprising the tongue 29, in the construction form already described with reference to Figure 4, can be seen too.

The two sides of the support member 18 are connected together by a support plane 78 that has a window 79 surrounded by a molded part 64 for the passage of the clamps 25 of contact and molded part 26 of seal (Figure 2).

The molded part 64, which projects to the base 20, performs the function of a mask that protects the tweezers 25 contact and prevents any accidental contact with these even when the plug body is in position disconnected from operation.

Outside the coupling seal between the base and cover, base 20 has two articulated arms 65 (of which only one is visible), each with a seat 66 into which one of the pins 22 of the hinge is mounted by elastic jump, and at the opposite end a pair of seats 67 within which a pair of pins are inserted, not visible in the figure, configured inside housing 28 of the cover in order to form a second joint between the base and the cover.

At the opposite end the base has two seats (only one 68 is visible) for the passage of a pair of screws 69, 70, which are screwed inside the cover, which connect surely the base and cover together.

The removal of the screws, which is carried out at through suitable openings in the support member, of the which one 80 is visible in the Figure, allows the cover to rotate around the joint (seat 67) and provide access inside the body of the plug.

Obviously the operation is only possible if the plug is removed from the electrical conduit; of what otherwise this would prevent access to the screw heads to unscrew them.

An accommodation, with peripheral walls 71, which receive the top of the contact sheet 27 and the clamp of corresponding tightening, comprising a torque 72, 73 of screw / nut, is formed in the base 20 along the appendix 61 protection along receiving the thrust of the blade Contact.

A fuse holder unit 74 is housed of detachable mode on base 20.

Unit 74 is correctly positioned by means of a pair of pins 75, 76 of base 40 that adapt to the force within corresponding seats (of which one, 77, is visible) in unit 74.

With two vertical partition walls 81, 82 the unit configures triple housing for a triplet corresponding fuse, only one of which 98 is sample, and by two sets of three fuse contacts, identified by references 83A, 83B respectively and each one provided with a connection terminal 91.

The contact pliers are inserted each inside and fixed on a short pin such as 84, 85 formed in the base of unit 74.

A triple set of accommodations 86, 87, 88 for a corresponding triple set of terminals of one type ordinarily known as "sleeve terminals" is formed at the end of the unit. One of these is illustrated in Figure and identified by reference 89.

The terminal essentially comprises a plate of metal, usually galvanically treated steel, folded to that forms a square ring, with a threaded hole for a screw Of tightening.

The square ring and the tightening screw corresponding are inserted into one of the housings, for example the housing 86, through an opening in the bottom (as indicated by arrow 90) and an opening upper (as indicated by arrow 91) that acts as a Highlight for the screw head, respectively.

The ends of the phase electric cables RST of a multipole cable inserted into the terminal body a through the sealed opening 23, and the contact tabs of a triple set of tweezers 83A, are inserted into the triple set of terminals located in housings 86, 87, 88.

Inside the plug body a seat 92 of anchor, which is known per se, with screws that are applied to the base 20, not illustrated, guarantees that the end of the cable Coated multiple is secured to the base.

The second third contact pliers set 83B are each connected to a clamp 25 that connects it  to the electrical conduit through a conductor length reconfigured electric 94 electrically welded to a plate pliers 83B on the one side and a clamp connection plate 95 over the other.

For simplicity and clarity only one of These connections are illustrated in the figure.

Preferably, the contact pliers 25 that they can vary in number according to the needs, they can be in number of four to allow the electrical connection of neutral N of the system in addition to the RST phases of a three-phase system.

The contact pliers 25 are contained individually in corresponding boxes 96 of plastic material with a lower opening from which the arms of the tweezers.

Conveniently, for reasons that will look more forward, the boxes 96 are also designed to contain a sleeve terminal of the type already described.

The boxes 96 are ordinarily placed by insertion from above, inside housings formed by walls 97 that extend vertically within the base 20.

Obviously, the base 20 has openings suitable that cannot be seen in Figure 7 so that arms of the contact pliers 25 pass outside in relation With these accommodations.

As already mentioned, these openings are all located within a shutter 26.

With respect to deck 21, there is little to add to what has already been said regarding the Figures precedents

It can only be indicated that cover 21 It can properly have openings (or even a simple window) closed by a plate 99 of welded transparent plastic material by heat to the cover so that the correct connection of the conductors to the phase and neutral terminals can be checked visually without the need to open the plug body (already has said that connections with the electrical conduit can be selective).

Indeed, through the convention international the various conductors in an electronic cable multiples are identified by a different color for the various phases, the neutral and the ground conductor.

Again, attending to ease and security maximum utilization of deck areas (and lever 39 of support member 18) on which pressure is to be exerted manual their surfaces can be conveniently identified they will be knurled, as shown in the figure, which improves the grab these.

In addition to this, the tabs 29 can be carriers of simple embossed marks, such as "ON", "OFF" that are visible in a mutually exclusive way, explicitly indicating the operating position of the plug, those of electrical connection and disconnection respectively.

Now we will consider in greater detail a preferred embodiment of the connection clamps 25 in the conduit electric and the corresponding container box 96.

Figure 8 illustrates in an exploded view expanded ordering, a preferred embodiment of the tweezers 25 intended for contact with the busbars in the duct electric.

The clamp comprises a contact member 100, obtained by cutting a copper / brass plate, which can be plated with tin or silver, curved to form a seat 102 that has two pointed arms 101 that extend opposite the which are designed to punch a plastic sheet 10 (Figure 1) and come into contact with a conduit conduit bar electric.

The seat also extends within a connection terminal 95, which has already been considered with reference to Figure 7.

Terminal 95 can be electrically welded by points at the end of a conductor or inserted into a sleeve clamp terminal.

To ensure adequate contact pressure on the arms 101, the clip also includes a supplement 103, of harmonic steel wire or plate, curved to form a wing open that mounts on seat 102, bypassing this.

Supplement 103 extends through two legs 104 that are located on the outer surface of the arms 101, compressing them together.

The ends of the legs 104 are sharp conveniently and extend somewhat beyond the extremes of the arms 101 so that they begin drilling the sheet 10 of insulation when the plug is compressed into position in which it has to work electrically, with greater efficiency than the arms 101 that only have to widen the drilling.

For that supplement 103 to be positioned correctly on the seat 102, the seat is provided conveniently with a recess 105 of housing and projections 106 which are obtained by folding back two pairs of tabs that They extend from the sides of the seat.

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Figure 9 is an enlarged perspective view of the box 96 which is designed to contain a clip 25 of contact and a terminal sleeve.

Figure 10 is a middle cross section to through box 96 according to the D-D view in Figure 9, and shows the electrical components housed therein.

With reference to these figures, box 96 it comprises a first portion 107 that forms a first housing prism shaped rectangular cross section that is open at the bottom and is provided at the top with a opening for the passage of the tightening screw 108 of a terminal 109 sleeve and with a screw head housing.

The bottom opening is used to insert the sleeve terminal body inside the housing, whose terminal is introduced by screw 108.

A second portion 110 of the box 96 forms a second accommodation that is open at the bottom and in communication With the first on one side.

A core 112 on which the seat of a contact clip 25, as indicated by the arrow 113, is formed in the second housing, supported by the wall 111 opposite the side in communication with the first accommodation.

This settlement operation, which is performed by automatic assembly machines, it takes place before the subsequent insertion, where specified, of the terminal sleeve, which takes place in the same direction, so that the terminal 95 connecting the clamp is inserted into the terminal 109.

Screw tip 108 acts directly on terminal 95.

Screwing screw 108 performs the tighten between terminal 95 and the bottom part of the terminal of a electrical conductor inserted in it.

The box 96, together with the electrical components assembled in it, it is easily inserted into one of the housing 97 of the plug body, where it is maintained by medium of interference between a pair of projections, one of the which 114 is visible in Figure 9, formed on walls opposite of the box, and corresponding projections 115 (Figure 7) formed within the opposite walls of the housings 97.

To allow protrusions 114 to rise over projections 115, securing the box in its housing with an elastic jump assembly, the walls of the box in which said protrusions are formed have slots 116, 117 laterally for protrusions 114 that allow the part placed between the grooves behaves like a leaf spring like a result of the relative elasticity of the plastic material of the which is formed the box.

The modular structure of the described plug satisfies the maximum variety of requirements with a minimum cost.

In the case of users who do not require the protection provided by fuses it is possible to offer a plug in which the fuse carrier unit is completely absent.

The connections of the various phases and the neutral of the multipolar cable selected by the user are made by the user tightening the various ends on the terminals housed in boxes 96.

These, and the corresponding plugs, can be present only in the required number, for example, to the connection of the neutral and a single phase, or only the three phases, or some of these.

Obviously, it will always be convenient provide the connection between the ground conductor and the terminal of Earth.

In the situation in which the protection provided by fuses, the plug can be provide with the fuse unit already installed and with the connection with contact clamps, except for the contract with the neutral, already done as described with reference to Figure 7.

In this case the various boxes 96 (except of the one that contains the contact pin with the neutral) can only contain 25 contact clamps, with some economy of components (sleeve terminals in three of the boxes 96).

The preceding description refers only to a preferred embodiment but it is obvious that many variants They can be applied to it.

In particular if the electrical conduit is tight not provided with an outer metal shell and driver ground is housed inside it with the tension and bars of mains voltage conduction, contact sheet 27 on the Figures 2, 6 and 7 can be replaced by a contact clamp that is identical or similar to those used for connection to the network and located in the same exit window 26 (Figures 2 and 7).

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In this case the earth contact clamp may conveniently be located closer to the joint over which the plug body is articulated with the member of support relative to the other of the clamps to ensure that a ground contact precedes the network connection in time when it is changed from the disconnected operating position to the electrically connected operating position (and obviously  still in this when you change the operating position connected to the operating position disconnected).

Claims (6)

1. Watertight plug for electrical connection to an electrical conduit (17), in which the insulation body (1) of an electrical conduit houses a plurality of conductors (6, 7, 8, 9) in hermetically sealed grooves by means of a sheet of insulating material (10) over its entire length, said plug being characterized in that it comprises: - a support member (18) to support and anchor to said electrical conduit, and - a plug body (19), which is sealed to except for a window surrounded by a molded part (26), the body of the plug being articulated in said member (18) of support in order to have an operating position of electrical connection with the conductors of the electrical conduit and a operating position disconnected, said body being provided with said window from which a plurality of electrical contact pliers (25), said body being anchored to said electrical conduit through said support member and, to take said connected operating position electrically, the contact pliers pierce said insulating sheet (10) and establish electrical contact with said conductors (6, 7, 8, 9), guaranteeing said molded part (26) of material elastic located within said window a tight connection between said plug body (19) and sheet 10 of said conduit electric, said body being provided with an opening (23) watertight for the passage of a coated cable and which is composed of a base (20) and a cover (21) connected tightly with a at intermediate sealing (58), said cover can be opened when said plug is removed from said electrical conduit to provide access to internal connection members (89) to said contact clamps (25) and the electrical connection between said coated cable and said internal members. - said member (18) of support with means (39, 40) for fixing to said duct electric, which means it can be operated manually for fixation and release only if said body is in said disconnected operating position, and means (29) of elastic jump fixing to secure the body in one or the other of said operating positions, said means being fixing releasable manually. 2. Plug according to claim 1, which comprises a contact sheet (27) that passes tightly inside of said base (20), said sheet establishing electrical contact with an external metallic closure (14) of said electrical conduit in said both operating positions when said member (18) of support is fixed to said electrical conduit. 3. Plug according to claims 1 or 2, which it comprises a fuse holder unit housed in said body (20) tight and provided with at least one clamp terminal (89) to connect the end of a cable wire inserted into said sealed body through said opening (23) to a fuse housed in said unit. 4. Plug according to any one of the preceding claims, wherein said base (20) forms a plurality of housings (97) for a plurality of boxes (96) of insulating material removably inserted in said housings, each of said boxes being designed to containing one of said tweezers (25) and a terminal (108, 109) of electrical connection 5. Plug according to any one of the preceding claims wherein said tweezers (25) of contact comprise a contact member (100) with a terminal of connection and adjacent contact arms (101) and a supplement (103) elastic mounted on the contact member (101) for push said arms against each other, having said supplement (103) feet that are sharp to pierce said sheet 10 of isolation. 6. Plug according to any of the preceding claims, wherein said member (18) of support comprises mechanical polarization means (37, 38) for ensure that there is a unique fixation position for said electrical conduit