EP3224915B1

EP3224915B1 - Device for the electrical interconnection of electrical cables and manufacturing process thereof

Info

Publication number: EP3224915B1
Application number: EP15818047.1A
Authority: EP
Inventors: Sandro Galli
Original assignee: Techno Group SRL
Current assignee: Techno Group SRL
Priority date: 2014-11-25
Filing date: 2015-11-20
Publication date: 2020-06-24
Anticipated expiration: 2035-11-20
Also published as: EP3224915A1; ITMO20140343A1; WO2016083965A1; ES2820582T3

Description

Technical Field

The present invention relates to a device for the electrical interconnection of electrical cables and a manufacturing process thereof.

Background Art

It is known that to connect two electrical cables, two terminals are generally used, one male and one female which can be mutually coupled together.
The end of each electrical cable, stripped of its insulating sheath, is inserted in an appropriate housing of the corresponding terminal where, by means of a mechanical screw or spring system, the mechanical retention is made of the electrical cable whilst ensuring at the same time the closing of the relevant power circuit.
The terminals equipped with a spring mechanism typically consist of a first portion with a spring for the connection to the electrical cable, and of a second portion provided with a pin (in case of male terminals) or a bush (in the case of female terminals), for the connection to the other terminal.
Both the first portion and the second portion are made by pressing, shearing and bending a metal sheet.
Once shaped, the first portion and the second portion are joined together by welding.
These traditional spring terminals do, however, have several drawbacks.
In this regard the fact is underlined in particular that the welding made to connect the first portion, provided with spring, to the second portion, provided with pin or bush, reduces the electrical conductivity of the material, greatly compromising the utility and possible use of such terminals.
To this must be added that the fabrication procedure adopted to produce these terminals requires the use of several pressing, bending and welding stages, with rather high production costs, which inevitably affect the retail price, with the risk of making these products less attractive to customers.

Description of the Invention

The main aim of the present invention is to provide a device for the electrical interconnection of electrical cables that, other conditions being equal, allows conducting more electrical current and is more economical compared to the terminals of known type.
Within the scope of this technical aim, another object of the present invention is to provide a process for the manufacture of a device for the electrical interconnection of electrical cables that can be implemented in a practical and easy way and with lower production costs compared to traditional systems. Another object of the present invention is to provide a device for the electrical interconnection of electrical cables and a process for the manufacture of a device for the electrical interconnection of electrical cables which allow to overcome the mentioned drawbacks of the prior art within the ambit of a simple, rational as well as easy and effective to use solution.
The above mentioned objects are achieved by the present device for the electrical interconnection of electrical cables having the features of claim 1. The above mentioned objects are achieved by the present process for the manufacture of a device for the electrical interconnection of electrical cables having the features of claim 5.
Special types of device for the electrical interconnection of electrical cables are disclosed in patent documents DE 102 55 190 , EP 1 753 095 , US 7 114 986 , US 2003/124916 , US 2006/199444 , DE 20 2010 016471 , DE 20 2014 100378 .

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become better evident from the description of a preferred but not exclusive embodiment of a device for the electrical interconnection of electrical cables, illustrated by way of an indicative, but non-limiting, example in the accompanying drawings in which:

Figure 1 is an axonometric view of the device according to the invention;
Figure 2 is an axonometric view of the device according to the invention in the configuration of use;
Figure 3 is a top view of the device according to the invention;
Figure 4 is an axonometric, partially broken-out view of a terminal according to the invention housed inside a multi-pole connector;
Figures 5 to 7 illustrate a process for the manufacture of the device according to the invention.

Embodiments of the Invention

With particular reference to such illustrations, globally indicated with reference number 1 is a device for the electrical interconnection of electrical cables.
The device 1 comprises:

a first male terminal 2, 3, of electrically conductive material, having a first distal portion 2 shaped like a pin and a first proximal portion 3 shaped to define at least a first bending spring 4 for locking a first electrical cable 5; and
a second female terminal 6, 7, of electrically conductive material, having a second distal portion 6 shaped like a bush and a second proximal portion 7 shaped to define at least a second bending spring 8 for locking a second electrical cable 9.

In this regard, the fact is underlined that, in the context of this treatise, the adjectives "distal" and "proximal" are used with reference to the relative position which the first male terminal 2, 3 and the second female terminal 6, 7 take on with respect to the corresponding electrical cables 5, 9 wherein the distal portions 2, 6 are located further away from the electrical cables 5, 9 while the proximal portions 3, 7 are placed closer to the electrical cables 5, 9.
The first distal portion 2 and the second distal portion 6 are sized so that the first distal portion 2 is insertable in the second distal portion 6, to create a coupling of the pin/bush type for the electrical connection of the electrical cables 5, 9. The electrically conductive material from which the first male terminal 2, 3 and the second female terminal 6, 7 are made is, e.g., phosphorous bronze or brass. The first male terminal 2, 3 consists of a first plate element sheared and folded to define both the first distal portion 2 and the first proximal portion 3, which are thus made in a single monolithic body.
The first plate element 2, 3 is obtained from a first sheet of flat plate 10, as is shown in Figure 6, comprising:

a first central body 11;
a first lateral segment 12 extending from one side of the first central body 11 along a first main direction 13 and is foldable on itself around the first main direction 13;
at least a first primary flap 14 extending from the first central body 11 along a first primary folding line 15 substantially parallel to the first main direction 13; and
a first secondary flap 16 extending from the first central body 11 along a first secondary folding line 17 substantially parallel to the first main direction 13 and from opposite side with respect to the first primary folding line 15, the first secondary flap 16 stretching out parallel to the first main direction 13 and being foldable at least in part on itself around a first secondary direction 18 substantially orthogonal to the first main direction 13.

This way, in the first male terminal 2, 3 obtained from the first sheet of flat plate 10 it is obtained that:

the first distal portion 2 is defined by the first lateral segment 12 folded on itself around the first main direction 13;
the first proximal portion 3 is defined by the first central body 11, by the first primary flap 14 folded around the first primary folding line 15 (in particular by 90°) and by the first secondary flap 16 folded around the first secondary folding line 17 (in particular by 90°) and around the first secondary direction 18 to define the first bending spring 4; and
the first electrical cable 5 is lockable between the first primary flap 14 and the first secondary flap 16.

In the particular embodiment shown in the illustrations, the first sheet of flat plate 10 comprises two of the first primary flaps 14 extending from the first central body 11 along the same first primary folding line 15 and which are substantially spaced apart to define a first slit 19.
This way, the first proximal portion 3 obtained from this first sheet of flat plate 10 has a first cut 20 defined by the first slit 19 and substantially facing the first bending spring 4, in which the first electrical cable 5 is fittable.
In other words, when the first electrical cable 5 is inserted between the first primary flaps 14 and the first secondary flap 16, the first cut 20 has the purpose of acting as a retaining knife thus allowing the first electrical cable 5 to deform itself at least partially inside it, creating a loop.
For the sake of simplicity, in the rest of this treatise we can refer to a generic first primary flap 14 to indicate, without distinction, one of the two or even both, if no explicit indication is provided to which of them reference is being made.
In the first proximal portion 3, the first bending spring 4 comprises at least a first projecting portion 21 which protrudes with respect to the first primary flap 14.
In practice, as is clearly shown in figure 3, the first bending spring 4 has a first edge 22 which, with respect to the first central body 11, is located at a distance D1 greater than the extension E1 of the first primary flap 14.
The first projecting portion 21 in fact is able to come in contact with a first externally-operated pressing element 23.
As shown in figure 4, the first male terminal 2, 3 is intended to be housed in a first multi-pole connector 24 used to contain a plurality of first male terminals 2, 3.
The first multi-pole connector 24 comprises a plurality of first pressing elements 23 arranged laterally to the first male terminals 2, 3 and which can be operated to press on the first projecting portion 21 of the first male terminals 2, 3.
When pressed, the first pressing elements 23 insist on the first bending springs 4 to move them away from the respective first primary flaps 14 and allow the introduction and removal of the first electrical cables 5.
In this regard the fact is underlined that, once the first sheet of flat plate 10 has been bent, the first secondary flap 16 is placed substantially inclined with respect to the first primary flap 14.
In particular the first secondary flap 16 forms an angle of about 45° with the first primary flap 14.
This way, the pressing action applied by the first pressing elements 23 can be directed either along a direction parallel to the first main direction 13 or along a direction orthogonal to the first primary flap 14, while still obtaining the same effect of compressing the first bending spring 4.
Similarly, the second female terminal 6, 7 consists of a second plate element sheared and folded to define both the second distal portion 6 and the second proximal portion 7, which are also made in a single monolithic body.
The second plate element 6, 7 is obtained from a second sheet of flat plate 25, as is shown in Figure 6, comprising:

a second central body 26;
two second lateral segments 27 extending from one side of the second central body 26 along a second main direction 28 and are at least in part foldable on themselves around the second main direction 28;
at least a second primary flap 29 extending from the second central body 26 along a second primary folding line 30 substantially parallel to the second main direction 28; and
a second secondary flap 31 extending from the second central body 26 along a second secondary folding line 32 substantially parallel to the second main direction 28 and from opposite side with respect to the second primary folding line 30, the second secondary flap 31 stretching out parallel to the second main direction 28 and being foldable at least in part on itself around a second secondary direction 33 substantially orthogonal to the second main direction 28.

This way, in the second female terminal 6, 7 obtained from the second sheet of flat plate 25 it is obtained that:

the second distal portion 6 is defined by the second lateral segments 27 folded on themselves around the second main direction 28;
the second proximal portion 7 is defined by the second central body 26, by the second primary flap 29 folded around the second primary folding line 30 (in particular by 90°) and by the second secondary flap 31 folded around the second secondary folding line 32 (in particular by 90°) and around the second secondary direction 33 to define the second bending spring 8; and
the second electrical cable 9 is lockable between the second primary flap 29 and the second secondary flap 31.

In the particular embodiment shown in the Figures, the second sheet of flat plate 25 comprises two of the second primary flaps 29 extending from the second central body 26 along the same second primary folding line 30 and which are substantially spaced apart to define a second slit 34.
This way, similarly to the first proximal portion 3, also the second proximal portion 7 has a second cut 35 defined by the second slit 34 and substantially facing the second bending spring 8, in which the second electrical cable 9 is fittable.
In other words, when the second electrical cable 9 is inserted between the second primary flaps 29 and the second secondary flap 31, the second cut 35 acts as a retaining knife, allowing the second electrical cable 9 to deform at least partially inside it, creating a loop.
For the sake of simplicity, in the rest of this treatise we can refer to a generic second primary flap 29 to indicate one of the two or even both, without distinction, if no explicit indication is provided to which of them reference is being made.
In the second proximal portion 7, the second bending spring 8 comprises at least a second projecting portion 36 which protrudes with respect to the second primary flap 29.
In practice, as is clearly shown in figure 3, the second bending spring 8 has a second edge 37 which, with respect to the second central body 26, is placed at a distance D2 greater than the extension E2 of the second primary flap 29. Similarly to the first projecting portion 21 in fact, the second projecting portion 36 is able to come in contact with a second externally-operated pressing element.
In this regard, the fact is underlined that the second female terminal 6, 7 is intended to be housed in a second multi-pole connector used to contain a plurality of second female terminals 6, 7.
The second multi-pole connector is similar to the first multi-pole connector 24 shown in figure 4 and, therefore, is not shown in detail in the illustrations for simplicity of exposition.
It is clear, however, that the second multi-pole connector comprises a plurality of second pressing elements which fully perform all the same functions as the first pressing elements 23 of the first multi-pole connector 24 and can be operated to press on the second projecting portion 36 of the second female terminals 6, 7.
When pressed, the second pressing elements insist on the second bending springs 8 to move them away from the respective second primary flaps 29 to allow for the introduction and removal of the second electrical cables 9.
Similarly to the first male terminal 2, 3, the second female terminal 6, 7 also has the second secondary flap 31 placed substantially inclined with respect to the second primary flap 29, to form in particular an angle of about 45°.
As with the first multi-pole connector 24, therefore, also in the second multi-pole connector, the pressing action applied by the second pressing elements can be directed either along a direction parallel to the second main direction 28 or along a direction orthogonal to the second primary flap 29, obtaining however, the same effect of compressing the second bending spring 8.
The device 1 is obtainable by means of the process of manufacture I, II, III, IV shown in the figures 5 to 7.
The process I, II, III, IV comprises the steps of:

providing a first flat plate 38 and a second flat plate 39 of electrically conductive material;
shearing and bending I, II the first flat plate 38 to define the first male terminal 2, 3 having the first distal portion 2 shaped like a pin and the first proximal portion 3 shaped to define at least the first bending spring 4 for the locking of the first electrical cable 5, the step of shearing and bending the first flat plate 38 being able to define both the first distal portion 2 and the first proximal portion 3, which are thus made in a single monolithic body; and
shearing and bending III, IV the second flat plate 39 to define the second female terminal 6, 7 having the second distal portion 6 shaped like a bush and the second proximal portion 7 shaped to define at least the second bending spring 8 for the locking of the second electrical cable 9, the step of shearing and bending the second flat plate 39 being able to define both the second distal portion 6 and the second proximal portion 7, which are thus made in a single monolithic body.

The step of shearing and bending I, II the first flat plate 38 comprises shearing I the first flat plate 38 with a first predefined template 40 (Figure 5) able to obtain the first sheet of flat plate 10 (Figure 6) comprising:

the first central body 11;
the first lateral segment 12 extending from one side of the first central body 11 along the first main direction 13 and is foldable on itself around the first main direction 13;
at least one of the first primary flaps 14, extending from the first central body 11 along the first primary folding line 15 substantially parallel to the first main direction 13;
the first secondary flap 16 extending from the first central body 11 along the first secondary folding line 17 substantially parallel to the first main direction 13 and from opposite side with respect to the first primary folding line 15, the first secondary flap 16 stretching out parallel to the first main direction 13 and being foldable at least in part on itself around the first secondary direction 18 substantially orthogonal to the first main direction 13.

The step of shearing and bending I, II the first flat plate 38 also comprises bending II the first sheet of flat plate 10 so that:

the first distal portion 2 is defined by the first lateral segment 12 folded on itself around the first main direction 13; and
the first proximal portion 3 is defined by the first central body 11, by the first primary flap 14 folded around the first primary folding line 15 and by the first secondary flap 16 folded around the first secondary folding line 17 and around the first secondary direction 18 to define the first bending spring 4.

Conveniently, the step of bending II the first sheet of flat plate 10 is performed by means of a first bending machine 42 (figure 7).
The step of shearing and bending III, IV the second flat plate 39 comprises shearing III the second flat plate 39 with a second predefined template 41 (figure 5) able to obtain the second sheet of flat plate 25 (figure 6) comprising:

the second central body 26;
two second lateral segments 27 extending from one side of the second central body 26 along the second main direction 28 and are at least in part foldable on themselves around the second main direction 28;
at least one of the second primary flaps 29 extending from the second central body 26 along the second primary folding line 30 substantially parallel to the second main direction 28; and
the second secondary flap 31 extending from the second central body 26 along the second secondary folding line 32 substantially parallel to the second main direction 28 and from opposite side with respect to the second primary folding line 30, the second secondary flap 31 stretching out parallel to the second main direction 28 and being foldable at least in part on itself around the second secondary direction 33 substantially orthogonal to the second main direction 28.

The step of shearing and bending III, IV the second flat plate 39 also comprises bending IV the second sheet of flat plate 25 so that:

the second distal portion 6 is defined by the second lateral segments 27 folded on themselves around the second main direction 28;
the second proximal portion 7 is defined by the second central body 26, by the second primary flap 29 folded around the second primary folding line 30 and by the second secondary flap 31 folded around the second secondary folding line 32 and around the second secondary direction 33 to define the second bending spring 8.

Conveniently, the step of bending IV the second sheet of flat plate 25 is performed by means of a second bending machine 43 (figure 7).

Claims

Device (1) for the electrical interconnection of electrical cables (5, 9), comprising:
- a first male terminal (2, 3), of electrically conductive material, having a first distal portion (2) shaped like a pin and a first proximal portion (3) shaped to define at least a first bending spring (4) for locking a first electrical cable (5);

- a second female terminal (6, 7), of electrically conductive material, having a second distal portion (6) shaped like a bush and a second proximal portion (7) shaped to define at least a second bending spring (8) for locking a second electrical cable (9);
said first distal portion (2) of said first male terminal (2, 3) being insertable in said second distal portion (6) of said second female terminal (6, 7) for the electrical connection of said electrical cables (5, 9);
wherein:
- said first male terminal (2, 3) consists of a first plate element sheared and folded to define both said first distal portion (2) and said first proximal portion (3), whereby said first distal portion (2) and said first proximal portion (3) are made in a single monolithic body;

- said second female terminal (6, 7) consists of a second plate element sheared and folded to define both said second distal portion (6) and said second proximal portion (7), whereby said second distal portion (6) and said second proximal portion (7) are made in a single monolithic body;
in which said first plate element (2, 3), constituting the first male terminal (2, 3), is obtained by shearing and folding a first sheet of flat plate (10), comprising:
- at least a first central body (11);

- at least a first lateral segment (12) extending in length from one side of said first central body (11) along a first main direction (13) and is foldable on itself around said first main direction (13);

- at least two first primary flaps (14) extending from said first central body (11) along a first primary folding line (15) substantially parallel to said first main direction (13) and foldable with respect to said first central body (11) around said first primary folding line (15); and

- at least a first secondary flap (16) extending from said first central body (11) along a first secondary folding line (17) substantially parallel to said first main direction (13), from opposite side with respect to said first primary folding line (15), said first secondary flap (16) stretches out parallel to said first main direction (13) and is foldable at least in part on itself around a first secondary direction (18) substantially orthogonal to said first main direction (13);
wherein:
- said first distal portion (2) is defined by said first lateral segment (12) folded on itself around said first main direction (13);

- said first proximal portion (3) is defined by said first central body (11), by said first primary flaps (14) folded around said first primary folding line (15) and by said first secondary flap (16) folded around said first secondary folding line (17) and around said first secondary direction (18) in order to define said first bending spring (4) of said first male terminal (2, 3);
in which said two first primary flaps (14) are substantially spaced from each other by a first slit (19), said first proximal portion (3) having a first cut (20) defined by said first slit (19) and substantially facing said first bending spring (4), in which said first electrical cable (5) is fittable and lockable between said first primary flaps (14) and said first bending spring (4); characterized by the fact that said first bending spring (4), included in said first proximal portion (3) of said first male terminal (2, 3), comprises at least a first projecting portion (21) which protrudes with respect to said first primary flap (14) and is able to come in contact with a first externally-operated pressing element (23), which is able to move said at least one first bending spring (4) away from said first primary flaps (14) and allow the introduction and removal of the first electrical cable (5) from said first male terminal (2, 3).
Device (1) according to claim 1, characterized by the fact that said second plate element (6, 7), constituting said second female terminal (6, 7) is obtained by shearing and folding a second sheet of flat plate (25), comprising:
- at least a second central body (26);

- at least two second lateral segments (27) extending from one side of said second central body (26) along a second main direction (28) and are at least in part foldable on themselves around said second main direction (28);

- at least two second primary flaps (29) extending from said second central body (26) along a second primary folding line (30) substantially parallel to said second main direction (28), and foldable with respect to said second central body (26) around said second primary folding line (30); and

- at least a second secondary flap (31) extending from said second central body (26) along a second secondary folding line (32) substantially parallel to said second main direction (28), from opposite side with respect to said second primary folding line (30), said second secondary flap (31) stretches out parallel to said second main direction (28) and is foldable at least in part on itself around a second secondary direction (33) substantially orthogonal to said second main direction (28);
wherein:
- said second distal portion (6) is defined by said second lateral segments (27) folded on themselves around said second main direction (28);

- said second proximal portion (7) is defined by said second central body (26), by said second primary flaps (29) folded around said second primary folding line (30) and by said at least one second secondary flap (31) folded around said second secondary folding line (32) and around said second secondary direction (33) to define said second bending spring (8) of said second female terminal (6, 7),

- said second electrical cable (9) is lockable between said second primary flap (29) and said second secondary flap (31).
Device (1) according to claim 2, characterized by the fact that said two second primary flaps (29) are substantially spaced apart by a second slit (34), defining a second cut (35) substantially facing said second bending spring (8), in which said second electrical cable (9) is fittable.
Device (1) according to claim 2 or 3, characterized by the fact that said second bending spring (8), included in said second proximal portion (7), comprises at least a second projecting portion (36) which protrudes with respect to said second primary flap (29) and is able to come in contact with a second externally-operated pressing element able to move away said at least one second bending spring (8) away from said second primary flaps (29) to allow for the introduction and removal of said second electrical cable (9) from said second female terminal (6, 7).
Process for the manufacture of a device (1) for the electrical interconnection of electrical cables (5, 9), comprising the steps of:
- providing a first flat plate (38) and a second flat plate (39) of electrically conductive material;

- shearing and bending said first flat plate (38) to define a first male terminal (2, 3) having a first distal portion (2) shaped like a pin and a first proximal portion (3) shaped to define at least a first bending spring (4) for the locking of a first electrical cable (5), said step of shearing and bending the first flat plate (38) being able to define both said first distal portion (2) and said first proximal portion (3) which are made in a single monolithic body; and

- shearing and bending said second flat plate (39) to define a second female terminal (6, 7) having a second distal portion (6) shaped like a bush and a second proximal portion (7) shaped to define at least a second bending spring (8) for the locking of a second electrical cable (9), said step of shearing and bending the second flat plate (39) being able to define both said second distal portion (6) and said second proximal portion (7) which are made in a single monolithic body;
in which said step of shearing and bending the first flat plate (38) comprises shearing said first flat plate (38) with a first predefined template (40) able to obtain a first sheet of flat plate (10) comprising:
- at least a first central body (11);

- at least a first lateral segment (12) extending from one side of said first central body (11) along a first main direction (13) and is foldable on itself around said first main direction (13);

- at least two first primary flaps (14) extending from said first central body (11) along a first primary folding line (15) substantially parallel to said first main direction (13), and foldable with respect to said first central body (11) around said first primary folding line (15); and

- at least a first secondary flap (16) extending from said first central body (11) along a first secondary folding line (17) substantially parallel to said first main direction (13) and from opposite side with respect to said first primary folding line (15), said first secondary flap (16) stretches out parallel to said first main direction (13) and is foldable at least in part on itself around a first secondary direction (18) substantially orthogonal to said first main direction (13);
in which said step of shearing and bending the first flat plate (38) comprises also bending said first sheet of flat plate (10), sheared, so that:
- said first distal portion (2) is defined by said first lateral segment (12) folded on itself around said first main direction (13); and

- said first proximal portion (3) is defined by said first central body (11), by said at least two first primary flaps (14) folded around said first primary folding line (15) and by said at least one first secondary flap (16) folded around said first secondary folding line (17) and around said first secondary direction (18) to define said first bending spring (4) of said first male terminal (2, 3); and

- said at least two first primary flaps (14), included in said first proximal portion (3), are substantially spaced from each other from a first slit (19) defining a first cut (20), substantially facing said first bending spring (4), in which said first electrical cable (5) is fittable and lockable between said first primary flaps (14) and said first bending spring (4);

- said first bending spring (4), included in said first proximal portion (3) of said first male terminal (2, 3), comprises at least a first projecting portion (21) which protrudes with respect to said first primary flap (14) and is able to come in contact with a first externally-operated pressing element (23), which is able to move said at least one first bending spring (4) away from said first primary flaps (14) and allow the introduction and removal of the first electrical cable (5) from said first male terminal (2, 3).
Process according to claim 5, characterized by the fact that said step of shearing and bending the second flat plate (39) comprises shearing said second flat plate (39) with a second predefined template (41) able to obtain a second sheet of flat plate (25) comprising:
- at least a second central body (26);

- at least two second lateral segments (27) extending from one side of said second central body (26) along a second main direction (28) and are at least in part foldable on themselves around said second main direction (28);

- at least two second primary flaps (29) extending from said second central body (26) along a second primary folding line (30) substantially parallel to said second main direction (28) and foldable with respect to said second central body (26) around said second primary folding line (30); and

- at least a second secondary flap (31) extending from said second central body (26) along a second secondary folding line (32) substantially parallel to said second main direction (28) and from opposite side with respect to said second primary folding line (30), said second secondary flap (31) stretches out parallel to said second main direction (28) and being foldable at least in part on itself around a second secondary direction (33) substantially orthogonal to said second main direction (28).
Process according to claim 6, characterized by the fact that said step of shearing and bending the second flat plate (39) also comprises bending said second sheet of flat plate (25), sheared, so that:
- said second distal portion (6) is defined by said second lateral segments (27) folded on themselves around said second main direction (28);

- said second proximal portion (7) is defined by said second central body (26), by said at least two second primary flaps (29) folded around said second primary folding line (30) and by said second secondary flap (31) folded around said second secondary folding line (32) and around said second secondary direction (33) to define said second bending spring (8); and

- said at least two second primary flaps (29), included in said second proximal portion (7), are substantially spaced from each other by a second slit (34) defining a second cut (35), substantially facing said second bending spring (8), in which said second electrical cable (9) is fittable and lockable between said two second primary flaps (29) and said second bending spring (8).