Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
SUPPORT FRAME OF LEATHERS TO BE DRIED AND/OR CONDITIONED
Document Type and Number:
WIPO Patent Application WO/2017/178987
Kind Code:
A2
Abstract:
A support frame (1) of leathers to be dried (or desiccated) and/or conditioned comprising a load bearing perimetrical structure (2) suitable to slide on air guides and to be folded, a flat metallic mesh (3) of the perforated sheet type, placed in the intermediate space (or room 4) defined by the load bearing perimetrical structure (2) and provided with two side faces (3a, 3b) opposite each other, each of which suitable to support one or more leathers to be dried and/or conditioned blocked to the flat metallic mesh (3) by means of pliers, and coupling means (5), through which the flat metallic mesh (3) is stably coupled with the load bearing perimetrical structure (2). In particular, the coupling means (5) include mechanical rapid hooking/engagement means (6) arranged in correspondence of at least a portion of the outer perimetrical edge (3c) of said flat metallic mesh (3) and of at least a portion of the inner perimetrical edge (2c) of said load bearing perimetrical structure (2).

Inventors:
GALIOTTO, Antonio (Via Bevilacqua, 1/A, Chiampo, 36072, IT)
Application Number:
IB2017/052115
Publication Date:
October 19, 2017
Filing Date:
April 12, 2017
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ERRETRE S.P.A. (Via Ferraretta 1, Arzignano, 36071, IT)
International Classes:
A47B57/16; C14B1/58
Attorney, Agent or Firm:
CONTADIN, Giorgio et al. (Notarbartolo & Gervasi S.P.A, Corso di Porta Vittoria 9, Milano, 35131, IT)
Download PDF:
Claims:
1. Support frame (1) of leathers to be dried and/or conditioned comprising:

- at least one load bearing perimetrical structure (2) suitable to slide on air guides and to' be folded;

- at least one flat metallic mesh (3) of the perforated sheet type, placed in the intermediate space (4) defined by said load bearing perimetrical structure (2) and provided with two side faces (3a, 3b) opposite each other, each of which is suitable to support one or more leathers to be dried and/or conditioned blocked to said flat metallic mesh (3) by means of pliers;

- coupling means (5), through which said flat metallic mesh (3) is stably coupled with said load bearing perimetrical structure (2),

characterized in that said coupling means (5) include mechanical rapid hooking/engagement means (6) arranged in correspondence of at least a portion of the outer perimetrical edge (3c) of said flat metallic mesh (3) and of at least a portion of the inner perimetrical edge (2c) of said load bearing perimetrical structure (2).

2. Frame (1) according to claim 1), characterized in that said mechanical rapid hooking/engagement means (6) substantially affect the entire outer perimetrical edge (3c) of said flat metallic mesh (3) and the entire inner perimetrical edge (2c) of said load bearing perimetrical structure (2).

3· Frame (1) according to claim 2), characterized in that said mechanical rapid hooking/engagement means (6) affect said entire outer perimetrical edge (3c) of said flat metallic mesh (3) and said entire inner perimetrical edge (2c) of said load bearing perimetrical structure (2) with the exception of the comers (7) of said flat metallic mesh (3) and said load bearing perimetrical structure (2).

4. Frame (1) according to any of the preceding claims, characterized in that said mechanical rapid hooking/engagement means (6) couple said flat metallic mesh (3) with said load bearing perimetrical structure (2) in such a way as to define between said flat metallic mesh (3) and said load bearing perimetrical structure (2) an interstitial perimetrical gap (8) and to arrange said outer perimetrical edge (3c) of said flat metallic mesh (3) away from and facing said inner perimetrical edge (2c) of said load bearing perimetrical structure (2).

5. Frame (1) according to any of the preceding claims, characterized in that said mechanical rapid hooking/engagement means (6) comprise: - a plurality of shaped teeth (9), each of which protruding from said outer perimetrical edge (3c) of said flat metallic mesh (3) in such a way as to define with said flat metallic mesh (3) a hooking undercut (10) communicating with the outside;

- a plurality of as many through holes (11) made in a tubular body (12) which forms said load bearing perimetrical structure (2), each of which faces one of said shaped teeth (9), in such a way that said shaped teeth (9) are stably housed in said through holes (11) by engagement and subsequent sliding inside said tubular body (12) until:

• a first inner side wall (13) of each of said shaped teeth (9), which is orthogonal to said outer perimetrical edge (3c) of said flat metallic mesh (3) and separates from said outer perimetrical edge (3c) of said flat metallic mesh (3) a second inner wall (14), orthogonal to said first inner side wall (13), of each one of said shaped teeth (9), positions close to an edge (15) of said flat metallic mesh (3) defining each of said through holes (11);

• a pre-established portion (16) of said tubular body (12) is housed inside said hooking undercut (10);

· said second inner wall (14) of each of said shaped teeth (9), that one turned towards said hooking undercut (10), positions close to the inner surface (12a) of said tubular body (12) of said load bearing perimetrical structure (2).

6. Frame (1) according to claim 5), characterized in that, in front view, each of said shaped teeth (9) presents a profile substantially in the shape of an inverted L.

7. Frame (1) according to claim 5) or 6), characterized in that each of said shaped teeth (9) presents a width development lower than the width development of each of said through holes (ll).

8. Frame (1) according to any of the claims 5) to 7), characterized in that a first plurality of said shaped teeth (9) located in a first perimetrical portion (17) of said flat metallic mesh (3) is arranged symmetrically with respect to a second plurality of said shaped teeth (9) located in a second perimetrical portion (18) of said flat metallic mesh (3), opposite to said first perimetrical portion (17) along a first longitudinal axis (X) or along a second longitudinal axis 00, orthogonal to said first axis (X), of said flat metallic mesh (3).

9. Frame (1) according to any of the claims 5) to 8), characterized in that a first series of said shaped teeth (9) arranged at the smaller side (19) of said flat metallic mesh (3) presents orientation identical only to that one of a second series of said shaped teeth (9) arranged at the larger side (20) consecutive to said smaller side (19) of said flat metallic mesh (3).

10. Frame according to any of the preceding claims, characterized in that it includes a first load bearing perimetrical structure and a second load bearing perimetrical structure, telescopically coupled with said first load bearing perimetrical structure, each of said first and second load bearing perimetrical structure defining said intermediate space,

Description:
SUPPORT FRAME OF LEATHERS TO BE DRIED AND/OR CONDITIONED

DESCRIPTION

The mvention disclosed herein refers to a support frame of leathers or similar laminar surfaces to be dried (or desiccated) and/or conditioned, especially tannery leathers typically but not exclusively wet leathers just undergone to retanning, dyeing and greasing for example in a tannery machine known as "drum" or still partly dampened with humidity leathers that must be stabilized by a treatment known in the tannery industry as ''conditioning", or dry leathers (which however always contain a value of humidity ranging between 5% and 15%) to which certain features are attributed thanks to the tensioning and simultaneous conditioning-

As it is well known in the tanning industry, the drying (or desiccation or exsiccation) of the leathers is a basic working which is typically carried out in the middle part of the entire tanning process, in which leathers already take the connotation of seirri-firushed products, and whose aim is to dry the leathers from the water excess accumulated in the previous workings.

When they have to undergo drying, the leathers, indeed, have been already subjected to at least the typical chemical and mechanical workings of the tar.ning industry, such as soaking, calcination, fleshing, splitting, de-calcination, degreasing, tanning, retanning, shaving, dyeing and greasing, in their proper and well-established operating sequence, and appear as wet semi-finished products.

The drying process is currently carried out with various plant solutions, depending on the type of leathers and final destination of the finished product: in this respect, drying for suspension, drying for nailing (in which leathers are coupled with support frames), drying for "pasting", vacuum drying are cited in this occasion, by way of example.

Prior patent document EP0838530 A2 shows a support frame of the metallic mesh type used in vacuum dryers, in which it is firstly highlighted that leather is supported exclusively and only by a heated work surface.

Such a support frame for vacuum dryers further comprises a first frame and a second frame, both of which are centrally provided with a metallic mesh and are firmly coupled each other, on one side, through moving means, for instance hinges, and on the opposite side through rapid engagement means that allow reciprocal fast hooking and release of these two frames. Therefore, the metallic rriesh doesn't support the leather and only contacts it to press it, while it rests on the work surface, and only when the lower frame closes on the upper frame so that the outer fine-gauge metallic mesh of the lower frame is in contact with the leather.

Basically, a typical drying and/or conditioning system of nailed leathers of known type comprises an operating tunnel that mainly develops according to a longitudinal direction and is provided with air conditioning devices (for example, axial fans) and/or traction organs (for instance pneumatic organs installed in the operating tunnel), suitable to act on the leathers in such a way as to dry them and/or stretch them respectively according to predetermined treatment and/or tensioning cycles and values.

A drying and/or conditioning plant of known type also includes a plurality of support frames, of the type provided with a metallic mesh made of perforated sheet supported by a perimetrical body and to which the present invention is specifically directed, each of which receives at least one leathers (fixed to it by means of special pliers applied to the perforated sheet where they keep it stretched).

A known drying and/or conditioning plant also includes moving means operatively connected with the support frames for conveying them along the aforesaid longitudinal direction according to a predefined speed inside the operating tunnel, to allow drying and/or the tensioning of the leathers, and outside the operating tunnel itself to allow the discharge of these leathers dried and/or tensioned in a given working cycle and the load of other leathers to be dried and/or tensioned in the next working cycle.

Nailing of the leathers on the perforated sheet of the respective support frames by said means aforesaid pliers is performed by an operator but much more often by at least one pair of operators in order to make the operation effective and efficient.

It should be noted at this stage that the metallic mesh of the prior document EP0838530 A2, particularly that one which contacts the leather, is a fine-gauge mesh, obviously different from a perforated sheet such as that one provided by the support frames of leathers which are of interest for the present invention and for which such a fine-gauge metallic mesh is totally unsuitable and unusable.

In addition, the fine-gauge metallic mesh described in EP0838530 A2 is not subject to any effort but needs to be replaced for wear during the periodic maintenance of the machine.

Once the application by nailing of the leathers on the support frames is finished, the latter are conveyed one at a time or by groups inside the operating tunnel of the plant where drying (or conditioning) of the leathers takes place by properly varying and modulating, depending on the selected settings (mostly determined by the type of the supported leather), the inner temperature and humidity conditions along the longitudinal development of the operating runnel.

Typically, a prior art support frame, used in drying and/or conditioning plants of leathers and specific object of the present invention, comprises a load bearing perimetrical structure suitable to slide on aerial guides and to be folded to allow operators load and stable application, by means of the nailing pliers, of the leathers to be dried and/or conditioned on both opposite side faces of a flat metallic mesh (also known as perforated sheet, in the tannery industry), disposed in the intermediate space defined by the load bearing perimetrical structure and on which the leathers are then properly but temporarily fixed. A of support frame of known type also includes coupling means through which the flat metallic mesh is firmly coupled with the load bearing perimetrical structure: typically, as foreseen by the notoriously most advanced and effective technological solutions, widespread and long-lasting in the field of the leathers tanning machinery, these known coupling means include a plurality of perimetrical elements of interconnection which are distinct and generally regularly spaced apart (or evenly distributed along the perimeter of the metallic mesh) each other which are coupled by welding both with the load bearing perimetrical structure and with the flat metallic mesh to which they are also firmly bound and secured by fastening means passing through the thickness of each perimetrical element and the metallic mesh (see in this connection the accompanying figure 1 showing a typical support frame of known type, in which the coupling means are indicated by A, the fastening means by Έ, the flat perimetrical mesh with R and the load bearing perimetrical structure with 5).

Clearly, this coupling system between flat metallic mesh and load bearing perimetrical structure, despite its operative effectiveness and in the knowledge that - at the expense of some older and less evolved constructive solutions of support frame - is the only one currently used, for many years, in the leather tanning industry for its reliability, presents some recognized drawbacks, the main one of which is constituted by the fact that its production involves rather articulate, laborious, relatively complex and rime<onsuming expensive workings, thus little quick certainly improvable in terms of efficiency.

All this negatively reflects in production costs that, without considering the cost of labor and raw materials, is excessively high or in any case certainly improvable and not optimal. A second drawback suffered by the prior art support frames derives from the fact that the welding with which the perimetrical inteTCOnnection elements are securely bound to the metallic mesh and to the load bearing perimetrical structure is notoriously a coupling system subjected to time to lose efficiency and retention capacity, with ail the obvious disadvantages that this involves ranging from the need for restoration interventions of the welding points up to the need to replace the perimetrical interconnection elements damaged by the welding loosening, if not, sometimes, the metallic mesh.

Starting from the awareness of the abovementioned drawbacks of the current state of art, the present invention seeks to fully remedy to them.

In particular, main purpose of the invention is to provide a support frame of leathers to be dried (or desiccated) and/or conditioned which can be assembled in a simpler, immediate and quicker way than known type support frames.

Within the scope of such a purpose, it is task of the present invention to provide a support frame of leathers to be dried and/oi conditioned which, cost of labor and raw materials used being equal, presents a lower production cost than the support frames of the prior art-

It is another purpose of the invention to design a support frame of leathers to be dried and/or conditioned which can be assembled also by personnel who are not necessarily skilled or with irrinimal experience in carrying out this type of operations in the construction of machines for the tanning industry.

Always in the cognitive sphere of the aforesaid main purpose, it is ' a further task of the invention to more quickly meet the demands of the tanning market, in particular of the industrial machines for the processing and treatment of the leathers dearly identifiable in it. It is a second purpose of the invention to implement a support frame of leathers to be dried and/or conditioned in which the coupling means which make the flat metallic mesh and the load bearing perimetrical structure integral each other able to keep unchanged their own structural and functional integrity for a much longer time than what is allowed by equivalent frames of known type.

It is therefore a purpose of the invention to give substance to a support frame of leathers to be dried and/or conditioned which, compared to the known art, reduces the maintenance and/or repair interventions of the aforesaid coupling means if not even complete replacement interventions of relevant parts of the support frame such as the flat metallic mesh itself. It is a last but not least purpose of the present invention to indicate a support frame of leathers to be dried and/or conditioned which can be produced without the provision of special machinery specifically designed and constructed for the intended use.

Said purposes are achieved by means of a support frame of leathers to be dried and/or conditioned according to claim 1, as hereinafter referred for the shortness of exposure.

Further constructive details of the support frame of the invention are given in the corresponding dependent claims.

The aforementioned claims, hereinafter specifically and concretely defined, are integral part of the present description.

Advantageously, the support frame of leathers to be dried and/or conditioned can be assembled more quickly and easily than the equivalent frames of the known art, to the point that the assembling can be performed also by personnel not so skilled in this kind of operations.

This is due to the fact that in the support frame of the invention, the coupling means firmly connecting the flat metallic mesh to the load bearing perimetrical structure properly include, instead of conventional and known perimetrical elements of interconnection welded to these components, mechanical rapid hooking/engagement means arranged at the outer perimetrical edge of the flat metallic mesh and at the inner perimetrical edge of the load bearing perimetrical structure.

This constructive design, in the support frame of the invention, represents a remarkable improvement in the technological development of this kind of applications of the tanning industry, for years anchored to the constructive concepts of the known art described above: in this respect, the support frame of the invention appears to be a revolutionary innovation to which no operator in the tanning industry had ever thought till now.

Still advantageously, the advantage just described also allows to provide support frames of leathers to be dried and/or conditioned which present a lower production costs and a more competitive selling price than the known art support frames.

Equally advantageously, the coupling means between the flat metallic mesh and the load bearing perimetrical structure provided in the support frame of leathers to be dried and/or conditioned of the invention are able to keep unchanged their own constructive and functional features for a longer time than analogous frames of the prior art, with all the induced advantages that this determines. In advantageous manner, furthermore, the support frame of leathers to be dried and/or conditioned of the invention can be delivered to customers faster than what it happens at present, to all the benefit of the satisfaction of the customers themselves increasingly needy in terms of delivery times.

Said purposes and advantages, as well as other significant Ones that will emerge later, will become more evident from the following description, relating to a preferred embodiment of the stipport frame of leathers to be dried and/or conditioned of the invention, given by indicative and illustrative, but not limitative, way with reference to the appended drawings in which:

- figure 1 is, as already highlighted, a front view of a support frame as it is currently conceived according to the prior art;

figure 2 is a front view of a first possible embodiment of the invention support frame;

- figures 3, 4 and 5 represent three distinct details of the mutually consecutive coupling steps of the flat metallic mesh to the load bearing perimetrical structure.

The support frame of leathers, in particular tannery leathers, to be dried and/or conditioned of the present invention is in particular of the so-called "nailing" type and is shown in figure 2, where it is globally numbered with 1.

As it can be seen, such a support frame 1 comprises:

- a load bearing perimetrical structure 2 suitable to slide on aerial guides (not shown in the drawings that follow for the sake of exposure simplicity) and to be folded by proper mechanical movements (also not shown) managed by a central processing or control unit (such as a PLC);

- a flat metallic mesh 3 of the perforated sheet type, placed in the intermediate space 4 and still contained in the encumbrance defined by the load bearing perimetrical structure 2 and provided with two side faces 3a, 3b opposite each other, each of which is suitable to support one or more leathers to be dried and/or conditioned (not shown for brevity) blocked to the flat metallic mesh 3 by the≤o»caIIed "nailing", i.e. by pliers (also not shown);

- coupling means, as a whole numbered with 5, through which the flat metallic mesh 3 is stably coupled with the load bearing perimetrical structure 2,

According to the invention, the coupling means 5 include mechanical rapid hooking/engagement means, generally numbered with 6, arranged at the outer perimetrical edge 3c of the flat metallic mesh 3 and at the inner perimetrical edge 2c of the load bearing perimetrical structure 2.

It is stated precisely from the outset that the one shown in figure 2 is a minimal support frame 1, having a single mesh and a single load bearing perimetrical structure, commonly used for leathers worked in the tanning industry, such as snake leathers and similar, having more reduced size or dimensions.

In particular, in this particular case, the mechanical rapid hooking/engagement means 6 are arranged substantially on the entire outer perimetrical edge 3c of the flat metallic mesh 3 and on the entire inner perimetrical edge 2c of the load bearing perimetrical structure 2.

It should be understood that in other embodiments of the support frame of the invention, not shown in the following, the mechanical rapid hooking/engagement means could be arranged in correspondence only of a predefined portion of the outer perimetrical edge of the flat metallic mesh and of a predetermined portion of the inner perimetrical edge of the load bearing perimetrical structure, without thus affecting the entire length of these perimetrical edges.

More in detail, the mechanical rapid hooking/engagement means 6 are arranged on the entire outer perimetrical edge 3c of such a flat metallic mesh 3 and on the entire inner perimetrical edge 2c of the load bearing perimetrical structure 2, with the exception of the angles 7 of the flat metallic mesh 3 and the load bearing perimetrical structure 2 itself.

In an apposite and advantageous way also to ease the mutual assembling phases, the mechanical rapid hooking/engagement means 6 couple the flat metallic mesh 3 with the load bearing perimetrical structure 2 defining between these components an interstitial perimetrical gap 8 and arranging the outer perimetrical edge 3c of the flat metallic mesh 3 away from and facing the inner perimetrical edge 2c of the load bearing perimetrical structure 2.

According to the preferred embodiment of the invention, the mechanical rapid hooking/engagement means 6 comprise:

- a plurality of shaped teeth 9, each of which protruding from the outer perimetrical edge 3c of the flat metallic mesh 3 in such a way as to define with the flat metallic mesh 3 itself a hooking undercut 10 communicating with the outside;

- a plurality of as many through holes 11 made in a tubular body 12 which forms the load bearing perimetrical structure 2, each of which faces one of the aforesaid shaped teeth 9, in such a way mat, as it can be derived by observing the details of figures 3, 4 and 5, the shaped teeth 9 are stably housed in the through holes 11 by engagement and subsequent Sliding inside the tubular body 12 until:

• a first inner side wall 13 of each of the shaped teeth 9 - which is orthogonal to the outer perimetrical edge 3c of the flat metallic mesh 3 and separates from the latter a second inner wall 14, orthogonal to the first inner side wall 13, of each of the shaped teeth 9 - positions close to an edge 15 of the flat metallic mesh 3 defining each of the through holes 11;

• a pre-established portion 16 of the tubular body 12 is housed inside the hooking undercut 10;

• the aforesaid second inner wall 14 of each of the shaped teeth 9, that one turned towards the hooking undercut 10, positions close to the inner surface 12a of the tubular body 12 of the load bearing perimetrical structure 2.

It follows that, also considering this constructive design, each of the shaped teeth 9 presents, in frontal view, preferably, a substantially L-inverted shaped profile.

In addition, each of the shaped teeth 9 conveniently presents a width development lower than the width development of each of the through holes 11, in order to allow the correct, easy, effective and simultaneous introduction by precision of all the shaped teeth 9 into the respective through holes 11.

Preferably but not necessarily, in the present invention, a first plurality of shaped teeth 9 located in a first perimetrical portion 17 of the flat metallic mesh 3 is arranged symmetrically with respect to a second plurality of shaped teeth 9 located in a second perimetrical portion 18 of the flat metallic mesh 3, opposite to the first perimetrical portion 17 along a first longitudinal axis Y or along a second longitudinal axis X, orthogonal to the aforesaid first axis Y, of the flat metallic mesh 3.

Moreover, a first series of shaped teeth 9 arranged at the smaller side 19 of the flat metallic mesh 3 presents orientation identical only to that one of a second series of shaped teeth 9 arranged at the larger side 20 consecutive side to the smaller side 19 of the flat metallic mesh 3.

Further constructive solutions of the current invention, not shown in the accompanying drawing tables, could provide that the support frame comprises a first load bearing perimetrical structure and a second load bearing perimetrical structure, telescopically coupled with the first load bearing perimetrical structure: each of these first and second load bearing perimetrical structure will thus define an intermediate space in which a respective flat metallic mesh is received.

In such a case, in the tannery industry, it is commonly referred to as expansion frame intended foi the support of animal leathers of greater size or dimensions, such as bovine leathers; which, as it is well known, represent as a whole the more relevant portion of leathers worked in the tannery industry.

Operatively, the operator (as already said, a person not necessarily of proven experience in this kind of operation) takes the flat metallic mesh 3 from the storage position at factory and makes it united to the load bearing perimetrical structure 2, while it is appropriately raised form the paving of the factory and supported by special trestles used in the industrial reference circle (tannery industry machinery) by means of the mechanical rapid hooking/engagement means 6 which, as said, distinguish the invention from the prior art. The operating sequence with which the coupling is carried out is shown in detail in the attached figures 3, 4 and 5, whereby the full insertion of the shaped tooth 9 into the respective through hole 11 of the tubular body 12 of the load bearing perimetrical structure 2 and the subsequent lateral sliding of the flat metallic mesh 3 as long as the edge 15 contrasts with the first side wall 13 and the portion 16 of the tubular body 12 is housed inside the hocking undercut 10 defined by the shaped tooth 9 (position shown particularly in figure 5) is firstly highlighted .

According to the description just provided, it is, therefore, understood that the support frame of leathers to be dried and/or conditioned, of the nailing or expansion type, which is the object of the present invention, achieves the purposes and reaches the advantages mentioned above.

However, another advantage of the invention is highlighted, consisting in the possibility of coupling the flat metallic mesh with the load bearing perimetrical structure not necessarily at the factory where the support frame is produced, but also for example at the using customer's factory.

This also reflects in obvious logistical advantages ~ of storage, especially for the manufacturer, and of moving and transport, since the flat metallic mesh can be stored and moved separately from the load bearing perimetrical structure, while remaining easily coupled with it quickly, for example in presence of a formal customer order. In the invention, furthermore, the provision of a support frame comprising a metallic mesh of the perforated sheet type coupled through mechanical rapid hooking/engagement means with the load bearing perimetrical structure is to the benefit of the constructor.

Contrary to the fine-gauge metallic mesh of the prior art document EP083S530 A2, the metallic mesh of the perforated sheet type of the support frame of the invention is not replaced during periodic and scheduled maintenance at factory: in the rare case where it is ruined, the resulting damage is very particular, as minimum, and moreover this event rarely leads to the replacement of the entire support frame (or in any case to the disassembly of such a support frame from the machine - drying and/or conditioning plant).

Upon execution, changes could be made to the support frame of leathers to be dried and/or conditioned of the invention, consisting, for instance, in mechanical rapid hooking/engagement means other than those ones shown in the appended figures and previously described with reference to the preferred embodiment of the invention.

It is, finally, clear that several other changes could be made to the support frame concerned, without departing from the principle of novelty intrinsic in the inventive idea expressed herein, as it is clear that, in the practical implementation of the invention, materials, shapes and sizes of the illustrated details could be changed, as needed, and replaced with others technically equivalent.

Where the constructive features and techniques mentioned in the following claims are followed by reference numbers or signs, those reference signs have been introduced with the sole objective of increasing the intelligibility of the claims themselves and therefore they have no limiting effect on the interpretation of each element identified, by way of example only, by these reference signs.