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Title:
TELESCOPIC MANEUVERING WRENCH FOR FACILITATING ANCHORING OF SANITARY FIXTURES TO A WALL
Document Type and Number:
WIPO Patent Application WO/2018/166659
Kind Code:
A1
Abstract:
T he telescopic maneuvering wrench (100) comprises: - a straight A lien wrench (4); - a recess (6) provided on the side surface of the straight A Ilen wrench (4); - a connecting element (7; S, C, F) for connecting the straight A llen wrench (4) and a screw element (3); - a hollow body (8) provided with snap-fit elements (9) for snap coupling with the straightA llen wrench (4), and a longitudinal cavity into which the straight A Ilen wrench (4) is inserted.

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Inventors:
CUCCINIELLO, Daniele (Via Terni 71, Civita Castellana, 01033, IT)
Application Number:
EP2018/025061
Publication Date:
September 20, 2018
Filing Date:
March 14, 2018
Export Citation:
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Assignee:
ALDERO INDUSTRIAL SUPPLIES S.R.L. (Via Quartaccio 1, Civita Castellana, 01033, IT)
International Classes:
B25B13/48; B25B15/00; B25B23/00; B25B23/10; E03C1/322; E03D11/14
Domestic Patent References:
WO2016057013A12016-04-14
WO2013167186A12013-11-14
Foreign References:
US20120180605A12012-07-19
US6038946A2000-03-21
US2679778A1954-06-01
DE202010009280U12011-12-22
DE202010009280U12011-12-22
DE202009014171U12010-03-04
DE102013112005A12015-04-30
Attorney, Agent or Firm:
STATTI, Francesco (ISEA S.R.L, Via G. Carducci 6, Civitanova Marche, 62012, IT)
Download PDF:
Claims:
C LAIMS

1. A telescopic maneuvering wrench (100) for facilitating the anchoring of wall- hung sanitary fixtures to a wall, characterized by comprising:

- a straight A lien wrench (4);

- a recess (6) provided on the side surface of the straight A I len wrench (4);

- a connecti ng element (7; S, C, F) for connecti ng the straight A I len wrench (4) to a screw element (3);

- a hollow body (8) provided with: snap-fit elements (9) for snap coupling with the straight A llen wrench (4), and a longitudinal cavity into which the straight A llen wrenc h (4) i s i nserted.

2. Telescopic maneuvering wrench (100) according to claim 1, wherein the .straight A Men wrench (4) comprises a radial ring (5) inserted in an annular ni p ( 16) provided on the top of said straight A llen wrench (4).

3. Telescopic maneuvering wrench (100) according to claim 2, wherein the connecting element(7) has a cylindrical body having: a side wall (14) with an internal thread that can engage an external thread of a screw element (3); a hole (12) on the base having a diameter comprised between the diameter of the ci rcumference ci rcumscri bed to the straight A llen wrench (4) and that of the ring (5); an abutment surface (13) extending radially between the hole (12) and the side wall (14) of the connecting element (7).

4. Telescopic maneuvering wrench (100) according to claim 3, wherein the connecti ng element (7) has wi ngs (11 ) on the outer side surface thereof.

5. Telescopic maneuvering wrench (100) according to one or more of the previous claims, wherein the hollow body (8) has a longitudinal cavity (8C) whose cross- section corresponds to the cross-section of the straight A lien wrench (4) to form a torsional coupling between the hollow body (8) and the straight A llen wrench (4).

6. Telescopic maneuvering wrench (100) according to claim 5, wherein the longitudinal cavity (8C) of the hollow body (8) has a prismatic shape.

7. Telescopic maneuvering wrench (100) according to claim 6, wherein the longitudinal cavity (8C) of the hollow body (8) has hexagonal cross-section. 8. Telescopic maneuvering wrench (100) according to one or more of the previous claims, wherein the hollow body (8) has an external prismatic shape.

9. Telescopic maneuvering wrench (100) according to claim 8, wherein the hollow body (8) has an external shape of hexagonal cross-section.

10. Telescopic maneuvering wrench (100) according to one or more of the previous claims, wherein the straight A llen wrench (4) is inserted in the longitudinal cavity (8C) of the hollow body (8) so that the snap-fit elements (9) face towards the connecting element (7; C, S, F).

11. Telescopic maneuvering wrench (100) according to one or more of the previous claims, comprising a screw element (3) associated with the straight A llen wrench (4), said connecting element between the straight A llen wrench (4) and the screw element (3) being a not releasable connecting element, preferably selected from the group compri si ng: a gl ui ng, a wel di ng, a pi asti c def ormati on.

12. Telescopic maneuvering wrench (100) according to one or more of the previous claims, wherein said recess (6) and said snap-fit elements (9) are configured so as to allow the mutual disengagement between the snap-fit elements (9) and the straight A llen wrench (4) in one direction and to prevent the release between the snap-fit elements (9) and the straight A llen wrench (4) in the opposite direction of a reciprocal sliding movement between the straight A I len wrench (4) and the hoi low body (8).

13. Telescopic maneuvering wrench (100) according to claim 12, wherein the recess (6) has a profile, in cross- section, having an angle where a generatrix is orthogonal to the axis ofthestraightA llenwrench (4) and the other generatrix has a inclination with respect to the previous one by the same inclination angle of teeth (9A) provided on the snap-fit elements (9) of the hollow body (8).

14 A kit comprising a telescopic maneuvering wrench (100) according to one or more of the previous claims, and a screw element (3) associated with the straight A llen wrench (4).

15. K it according to claim 13, further comprising a tool (10) for rotating the telescopic maneuvering wrench.

16. A telescopic maneuvering wrench (100) to facilitate the anchoring of a wal l- hung sanitary fixture to a wall, characterized by comprising:

- a straight A lien wrench (4) with hexagonal head;

- a radi al ri ng (5) i nserted i n a f i rst recess provi ded on the top of sai d straight A 11 en wrench (4);

- a second recess (6) provided on the side surface of the straight A I len wrench (4);

- a connecting element (7) for connecting the straight A lien wrench (4) and a screw element (3), having:

Δ cylindrical shape si milar to a screw cap;

Δ an i nner thread correspond! ng to that of said screw element (3); Δ a hole (12) on the base, whose diameter is comprised between the diameter of the circumference circumscribed to the straight A llen wrench (4) with hexagonal head and that of the radial ring (5);

Δ a surface (13) between the hole (12) and the threaded wall of the connecting element (7) able to abut against the radial ring (5);

- a hollow hexagonal prism (8) with two portions where snap-fit elements (9) are provided.

Description:
T elescopic maneuvering wrench for facilitating anchoring of sanitary fixtures to a wall

Description Field of the invention

The present invention relates to the field of systems for fixing wall-hung sanitary fixtures; more specifical ly it relates to a telescopic maneuvering wrench for facilitating anchori ng thereof to a wal I . Background to the invention

It is well known that the operation of systems for fixing wall-hung sanitary fixtures and the like is ensured by the use of a maneuvering wrench that, by facilitating the forward movement of a screw or dowel element, allows the anchoring of the wall-hung element to a wall.

Typically, the access to the fixing system is limited and not always visible by the pi umber. F or exampi e, i n the case of wal I - hung sanitary fixtures the access i s from the bottom and it is not possi ble to see what is done, and the operation is therefore difficult.

T he current art systems mai nly used to f aci I itate the anchori ng of a wal I- hung sanitary fixture to a wall are:

- a plastic tube attached to the fixing system which, by means of a helical torsion spring, is in close connection with the screw which provides the anchorage. T he insertion of the maneuvering wrench, which is, in this case, a hex key or A llen wrench, is facilitated by the presence of said small tube that acts as a guide. In fact, inserting the maneuvering wrench inside it, the wrench will be surely positioned in the hexagonal head of the screw, thus ensuri ng a perfect screwi ng of the same screw.

The use of the tube is disadvantageous when the sanitary fixture to be hung to the wall has a very high casing and is not far from the floor. In this case, the maneuvering space will be very limited, due to the small distance from the ground and it will be therefore difficult to insert the wrench into the guide tube. T he aforesaid anchoring maneuver is often impossible or, at best, long and difficult.

- A maneuvering wrench, disclosed in WO2013167186, consisti ng of a hexagonal A lien wrench di rectly attached to the screw element as a si ngle body. In this case, the two pieces are al ready coupled together and it is not necessary for the plumber to insert the maneuvering wrench into the hexagonal head of the screw. T he disadvantage of this known system is that, working with sanitary fixtures of different heights, it would be necessary to have maneuvering wrenches of different lengths avail able and therefore the wrench should be cut each time according to need. In this case again the installation process is longer and less easy.

- A system, disclosed in D E 202010009280, able to fit on a clamping sleeve and on which an A llen wrench is inserted.

T he drawback of this system is that, si mi larly to what descri bed above, i n the case of sanitary fixtures of different heights, a wrench of the same height as the sanitary fixture would be requi red and therefore the f ixi ng kits usi ng systems of this type are not universal .

A common disadvantage to all the documents disclosed above is that none of the systems used allows the pi umber to see what he/she is doing. Summary of the Invention

A n object of the present i nvention is to overcome at least partial ly the drawbacks of the above mentioned current art, providing a universal maneuvering wrench suitable to adapt to all types of wall-hung sanitary fixtures.

A further object of the present invention is to provide the possibility of performing a visible maneuvering according to the principle described hereinafter, thus facilitating the i nstal I ati on operati ons. According to one aspect, a telescopic maneuvering wrench is provided to facilitate the anchoring of a wall-hung sanitary fixture, comprising a straight A llen wrench, a recess provided on the side surface of the straight A llen wrench and a connecting element between the straight A I len wrench and a screw element. T he maneuveri ng wrench further comprises a hollow body provided with snap-fit elements for snap-coupli ng to the straight A llen wrench, and a longitudinal cavity into which the straight A llen wrench is inserted.

F urther features and embodi ments are set forth i n the attached clai ms, which form an integral part of the present description.

F urther features and advantages of the i nventi on wi 11 be apparent from the descri pti on below of a preferred but not exclusive embodiment of a telescopic maneuvering wrench, illustrated by way of non-limiting example in the attached drawings.

B ri ef descri pti on of the drawi ngs

T he i nventi on wi 11 be better understood by f ol I owi ng the descri pti on

- Fig. 1 is an exploded view of a wrench according to the invention in an embodiment thereof;

- Figs. 1A, 1 B and 1 C are enlargements of details of Fig. 1;

- Fig. 2 is a three-dimensional view of the maneuvering wrench in the retracted position associated with a system for fixi ng sanitary fixtures;

- Fig. 3 is a three-di mensional view of the maneuveri ng wrench i n extracted position;

- Fig. 4 is a three-dimensional view of the use of the maneuvering wrench in the retracted position for fixing a wall-hung sanitary fixture;

- Fig. 5 is a three-dimensional view of the use of the maneuvering wrench in the extracted position for fixing a wall-hung sanitary fixture;

- F ig. 6 i 11 ustrates an alternative embodi ment;

- Fig. 7 is an exploded view of a modified embodiment;

- Figs. 8(A), 8(B) and 8(C) show modified embodiments of the connection between the A I len wrench and the screw element; and

- Figs. 9(A)-9(D) show exemplary embodiments of the snap-fit elements connecting the straight A llen wrench and the hexagonal prism. D etai I ed descri pti on of the i nventi on

With initial reference in particular to Fig.1 , according to a preferred but not li miting embodiment, the present invention relates to a telescopic maneuvering wrench indicated as a whole with number (100) to facilitate the anchoring of a wall-hung sanitary fixture, the wrench being comprised of the elements described below.

According to the embodiment of Fig. 1, the telescopic maneuvering wrench (100) comprises a straight A llen wrench (4) with hexagonal head. The telescopic maneuvering wrench (100) further comprises a ring (5), also visible in the detail of Fig. 1A, inserted in a first recess or groove (16) provided on the top of the straight A llen wrench (4). A second recess (6), also visible in the detail of Fig. 1 B, is provided on the side surface of the straight A llen wrench (4).

In the example of Fig.1 the telescopic maneuvering wrench (100) further comprises a cylindrical connecting element (7) between the straight A llen wrench (4) and a screw element (3), for example a hex socket set screw. T he connecting element (7) is similar to a screw cap with a hole (12) on the base. The hole (12) has a diameter comprised between the diameterof the circumference circumscribed to the straight A I len wrench (4) with hexagonal head and that of the ring (5), shown in the detail of Figure 1 C, illustrating the cross-section of the connecting element (7). A n annular surface (13) comprised between the hole (12) and an internally threaded wall (14) of the connecting element (7) forms a radial abutment for the ring (5).

The telescopic maneuvering wrench (100) further comprises a hollow prismatic body, having a hexagonal cross-section, for instance, hereinafter briefly referred to as "hollow hexagonal prism" and indicated with (8). T he hollow hexagonal prism (8) is provided with two portions in the form of elastic appendices which form snap or snap-fit elements indicated with (9). T he snap-fit elements (9) may comprise teeth (9A) able to snap fit i n the recess (6) provided on the straight A I len wrench (4) as descri bed below.

T he telescopic maneuvering wrench (100) can also comprise an optional L-shaped A llen wrench (10). T he L-shaped A llen wrench (10) can be omitted and a different tool can be used instead of it, for example a monkey wrench, a ratchet wrench, a socket wrench or other equivalent tool, able to co-act with the hollow hexagonal prism (8) for the purposes explained below.

As shown in particular in Fig. 1 B, the recess (6) can be provided with a specific geometry: in cross-section the profile is represented by an angle where a generatrix is orthogonal to the axis of the straight wrench (4) and the other generatrix has an inclination, with respect to the previous one, by the same angle of the teeth (9A) of the snap-fit elements

(9) of the hollow hexagonal prism (8). In other words, the recess is defined by a substantially flat annular surface, orthogonal to the axis of the straight A llen wrench (4), and by a truncated-conical surface. T he truncated-conical surface is di rected so that the recess (6) has a depth that gradually decreases towards the end of the straight A llen wrench (4) where the first recess or annular nip (16) is formed.

T he ri ng ( 5) can be an el asti c ri ng made of metal or pi asti c. In other embodi ments the ring (5) may bea split pin, or any element capable of increasing the cross-secti on with respect to that of the straight A llen wrench (4). In other words, once housed in the first recess or annular nip (16) the ring (5) forms a shoulder projecti ng from the outer hexagonal prismatic surface of the straight A I len wrench (4).

In the preferred embodi ment shown in Fig.1 , the connecti ng element (7) between the screw element (3) and the straight A llen wrench (4) is a plastic cap with an internal thread corresponding to that of said screw element (3), i.e. suitable to be screwed onto the screw element (3). The hole (12) of the connecting element (7) allows the passage of the straight

A llen wrench (4). T he components of the telescopic maneuver! ng wrench (100) descri bed above can be assembled as follows.

The screw element (3), or hex socket set screw, is inserted on the hexagonal head (4A) of the straight A llen wrench (4). In other words, the upper end (in Fig.1) of the straight A llen wrench (4) is inserted into the hexagonal recess of the screw element (3).

The connecting element (7) is inserted from the bottom upwards around the straight A llen wrench (4), so that the ring (5) abuts on the surface (13) and the internal thread of the wall 14 remains free and not engaged by the straight A llen wrench (4).

Atthis point it is possibleto screw the connecti ng element (7) onto the screw element (3), thus ensuring an integral connection between the screw element (3) and the straight A lien wrench (4).

The size of the hexagonal cavity of the prism (8) depends on the size of the straight wrench (4). The coupling between the two elements must be characterized by longitudinal interference along the larger size of the wrench (4).

The straight A llen wrench (4) is inserted into the hollow hexagonal prism (8) so that the snap-fit elements (9) face the connecting element (7). In other words, the straight A llen wrench (4) is inserted in the hollow cavity of the hollow hexagonal prism (8) with the end (4B) thereof opposite to the end or head (4A) constrained to the screw element (3). The insertion is performed from the side of the hollow hexagonal prism (8) where the snap-fit elements (9) are provided. The end (4B) is inserted into the longitudinal cavity of the hollow hexagonal prism (8) by deforming the snap-fit elements (9) radially outwardly, since the teeth (9A ) of the snap-fit elements reduce the passage cross-secti on of the I ongitudi nal cavity of the hollow hexagonal prism (8). T he deformation is facilitated by the fact that the teeth (9A) have distal surfaces which are inclined towards the axis of the hollow hexagonal prism (8).

The sliding of the hollow hexagonal prism (8) along the straight wrench (4) is free until the snap-fit elements (9) achieve the second recess (6) provided on the straight A llen wrench (4). At this point, the teeth (9A) of the snap-fit elements (9) are snap inserted into the second recess (6) and stop the reciprocal sliding between the hollow hexagonal prism (8) and the straight A llen wrench (4). T he telescopic maneuvering wrench is now assembled.

However, the reciprocal sliding between the hollow hexagonal prism (8) and the straight A llen wrench (4) can continue until the straight A llen wrench (4) is almost fully retracted into the hollow hexagonal prism (8). This is possible by applying a force sufficient to elastically deform the snap-fit elements (9) in radial direction outwardly, by making the inclined surfaces of the teeth (9A) slide along the portion of truncated-conical surface defining the second recess (6). When deformed radially outwardly, the teeth (9A) exit from the second recess (6) and slide on the prismatic surface of the straight A llen wrench (4) towards the connecti ng element (7) even up to abut agai nst it.

From the position of maximum retraction, i.e. the position where the straight A llen wrench (4) is completely inserted in the longitudinal cavity of the hollow hexagonal prism (8), the straight A lien wrench (4) can be removed, but not completely. When the teeth (9A) of the snap-fit elements (9) enter the second recess (6) again, the flat annular surface of the second recess (6), orthogonal to the axis of the straight A llen wrench (4), provides an abutment for the teeth (9A) of the snap-fit elements (9). The geometric shape of the teeth (9A) and of the second recess (6) is such that it does not exert a radial outward deformation of the teeth (9A), which therefore prevent the straight A 11 en wrench (4) from bei ng further extracted from the hoi low hexagonal prism (8).

The telescopic maneuvering wrench of the present invention is therefore a length- adjustable wrench.

The minimum extension occurs when the hol low prism (8) abuts against the connecting element (7), while its maximum extension occurs when the teeth (9A) of the snap-fit elements (9) are locked at the second recess (6). T his second condition is shown in the detail of Fig. 1 B. In an alternative embodi ment, illustrated in the exploded view of Fig. 6, on the side surface thereof the connecting element (7) is provided with wings (11) having the function of facilitating the operator in screwing said connecting element (7) onto the screw element (3).

Once the telescopic maneuvering wrench (100) has been assembled as described above, it can be used by acti ng thereon using the L-shaped A llen wrench (10), inserting this latter inside the hollow hexagonal prism (8). In an alternative embodiment, the L-shaped A llen wrench (10) can be replaced by a conventional wrench or by a ratchet wrench or a socket wrench or any other equivalent tool.

In the illustrated embodiment the through cavity of the hollow hexagonal prism (8) has a hexagonal cross- section, so as to couple with the straight A lien wrench (4), which can be di rectly coupl ed to the L -shaped A 11 en wrench ( 10) . H , al so the outer surface of the hoi I ow hexagonal prism (8) has preferably a hexagonal prismatic cross-section for coupling to a wrench or any tool other than the L-shaped A llen wrench (10). However, the hollow body (8) may also have a non-hexagonal prismatic shape, i.e. with an outer surface of non- hexagonal cross- section, but preferably at least partially prismatic, to allow the gripping by a maneuvering tool acting on the outside of the hollow body (8). In less preferred embodiments, the hollow body (8) may bean elongated and inside hollow body, with a cavity of hexagonal cross- section or i n any case such as to be able to couple with an A lien wrench, but with an external surface of any shape, even of circular cross- section. In this case, the operation is carried out preferably by acting with a tool (L-shaped A llen wrench (10) for example) which couples to the through longitudinal cavity and not to the outer surface of the hollow body (8).

Figs. 2 and 3 show two arrangements of the telescopic maneuvering wrench (100) i n two positions corresponding to two different lengths that can be obtained by telescopically extending the components (4) and (8). In these two figures, the telescopic maneuvering wrench is shown in combination with a devicefor mounting a wall-hung sanitary fixture, the device being indicated as a whole with number (20). T he mounting device (20) shown in the attached figures is known per se and it is indicated just by way of example. In fact, from the description below, those skilled in the art will understand that the telescopic maneuvering wrench illustrated herein can be used in combination with several different systems and devices for mounting wall-hung sanitary fixtures equipped with a screw element (3), preferably a headless one, associ able with the telescopic maneuvering wrench (100).

In the i 11 ustrated exampl e the devi ce (20) compri ses a cl ampi ng cone (21 ) and a si eeve (22). T he device (20) may be designed as described for example in DE 202009014171 or in D E 102013112005, the content whereof is i ncorporated i n the present descri ption. T he device (20) is fixed to a sanitary fixture (30) to hang to a wal I, as shown i n F ig.5. In a known manner, the sleeve (22) has a threaded radial hole in which the screw element (3) is screwed, which co-acts with a wall-mounted pin (not shown), which is inserted axial ly through the device (20) and is provided with an elongated slot. By screwing the screw element (3) transversely into the radial hole of the sleeve (22), the tip of the screw element (3) co-acts with the elongated slot of the wal l-mounted pi n, thus generati ng a thrust of the sanitary fixture (30) against the wall (P) on which it shall be hung. T he mounting is known and does not require further descriptions.

T he telescopic maneuvering wrench (100) described above is engaged with the device (20) once this latter has been fixed to the sanitary fixture (30) simply by screwing the screw element (3) into the radial threaded hole of the sleeve (22). T he fact that the telescopic maneuvering wrench can lengthen and shorten telescopically allows the operator to arrange the distal end of the hollow hexagonal prism (8) in a position that is easily accessible from outside the sanitary fixture (30), as shown in Fig.5. In this way, using a tool, for examplethe L -shaped A llen wrench (4), it is possible to turn the telescopic maneuvering wrench easily.

Once the screw element (3) has been tightened i n the sleeve (22) and the sanitary fixture has been correctly fixed to the wall (P), the L -shaped A llen wrench (10) can be removed and the telescopic maneuvering wrench (100) can be slightly shortened so as to remain integrally and invisibly housed inside a cavity (31) of the sanitary fixture (30), as schematically shown in Fig.4.

In this way the telescopic maneuvering wrench (100) is available for subsequently disassembling the sanitary fixture (30), but is substantially not visible and not accessible by the user.

It should be understood that usually the sanitary fixture (30) requires two mounti ng devices (20) and therefore two telescopic maneuveri ng wrenches (100).

It is clearly apparent from the description above that the essential elements for achieving the object of the present invention are: the hollow body (8) with the snap-fit elements (9), the straight A llen wrench (4) with the recess (6) and a system for fixing the screw element (3) to the head (4A) of the straight A llen wrench (4). A complete kit for mounting a sanitary fixture (30) shall comprise, in addition to the aforementioned components of the telescopic maneuvering wrench (100), also a mounting device (20) and the screw element (3).

Fig.7 is an exploded view of this set of essential components, whose assembly occurs as described above.

However, it should be understood that even if Fig.1 shows an example where the screw element (3) is constrained to the straight A lien wrench (4) using the ring (5) and the connecting element (7), other equivalent ways may be provided for achieving such fixing.

Figs. 8(A), 8(B) and 8(C) schematically show three ways for fixing the screw element

(3) to the straight A llen wrench (4). More particularly, Fig. 8(A) schematically shows a system of fixing by means of radial plastic deformation of the screw element (3) against the straight A llen wrench (4). The radial necking, schematized through arrows (F), can cause a permanent deformation of the recess of the screw element (3) against the head (4A) of the straight A lien wrench (4), possibly causing a coupling with the recess (5), if any. Fig. 8(B) schematically shows a way for coupling the screw element (3) and the straight A llen wrench (4) by means of adhesive (C), while in Fig. 8(C) the coupling is through welding (S).

While in the embodiment described above with specific reference to Fig.1, the snap- fit elements (9) are made in the form of two substantially symmetrical opposite elastic tabs provided with two teeth (9A), in other embodiments, the snap coupling can be obtained with a different number of tabs and/or with tabs of different shape. Figs. 9(A)-9(D) show four alternatives, each in front view and in an axonometric view, of possible configurations of the snap-fit elements, always indicated with (9) and provided with teeth (9A). T he embodiment of Fig. 9(C) is that al ready descri bed with reference to F ig.1. In general, the snap-fit elements 9 can be formed by notches that start from the distal surface of the prism (9) and extend parallel to the longitudinal direction thereof, forming the tabs 9.

In Figs. 9(A)-9(D), the number (8C) indicates the longitudinal, or axial, through cavity of the hollow hexagonal prism (8). T he designation of the body (8) as a "hexagonal" prism refers in particular to the hexagonal shape of the longitudinal cavity (8C) which extends along the entire length of the hollow hexagonal prism (8). T he hexagonal shape is particularly advantageous as it allows using standard bars of hexagonal cross-section for producing the straight A llen wrenches (4), and therefore screw elements (3) constituted by normal hex socket set screws, in combination with L-shaped A llen wrenches (10), if necessary. However, a prismatic shape other than the hexagonal one is also possi ble, provided that it is possibleto have a torsional fit-coupling between the straight A llen wrench (4) and the hoi low prism (8), as wel I as between the straight A I len wrench (4) and the screw element (3).

The materials and the dimensions of the invention as described above, il lustrated in the accompanying drawings and claimed in the following claims, may be any according to the specific needs. Moreover, all the details can be replaced with other technically equivalent details, without departi ng from the protective scope of the present invention.