"Method and apparatus for the realization of integral elastic supports for the human body"

DESCRIPTION Field of application

This invention is generally applicable to the field of processing plastic materials and refers in particular to a method and an apparatus for the production of integral elastic supports for the human body, in particular for the forming of seat structures such as a frame for a saddle or for vehicle seats.

State of the Art

Known supports for the human body, in particular saddles for bicycles or motorcycles, seats for vehicles and seats generally, are built of a bearing frame with a matrix formed by one or more layers of plastic material with which a strengthening element in fibrous material is permanently associated.

The latter is generally sunken within the matrix itself or is fixed, mechanically or by gluing, to one or more of the layers forming the matrix, in order to guarantee greater mechanical characteristics as well as relative lightness to the support.

Typically, the fibres of the strengthening element are distributed and oriented, according to a general project design, in pre-set directions along which the values of maximum tension are imagined to be concentrated.

A clear drawback of these known solutions is constituted by the fact that, in order to guarantee that the fibres are correctly oriented, they are distributed in a substantially uniform manner even in the areas or points in which this is not strictly necessary.

The less than optimal distribution of fibres according to the specific desired result therefore produces a useless increase in the overall weight of the support as well as increased production costs.

To avoid these drawbacks, W09300621 makes available a method for the production of mechanical elements comprising a strengthening layer in fibrous material sunken into a plastic matrix in which the quantity and orientation of each fibre is pre-set following a computerised calculation which presents as an input data the status of the effective tension of the mechanical element in the condition of maximum stress.

The fibrous strengthening element made according to the distribution diagram calculated in this way is then sunken within the resinous matrix in order to obtain a semifinished product that constitutes the structure of the support or the support itself.

This solution, while assuring the optimal distribution of the fibres, with consequent savings on material and the reduced weight of the finished product, is however not free from drawbacks.

In fact, the forming phase of the plastic matrix is carried out without previously establishing either the strictly necessary quantity of resinous material to be used nor its optimal distribution to minimise consumption and avoid areas in which the concentration of resin is more or less than needed.

Furthermore, the distribution of the fibres is done following a diagram that reproduces the condition of estimated maximum tension for the mechanical element during use in a typical situation, without considering the anatomy of the specific user.

Presentation of the invention

The object of this invention is to overcome the above-described drawbacks, providing a method and an apparatus for the production of integral elastic supports for the human body that present characteristics of high efficiency and relative low costs.

A specific object is to provide a method and an apparatus for the production of elastic supports that offer high mechanical resistance and relatively low weight in order to minimise the production costs of the support.

A further object is to provide a method and an apparatus for the production of elastic supports that are extremely customisable according to the anatomic characteristics of the specific end user.

These objects, as well as others which will become clearer hereafter, have been achieved by a method, in accordance with claim 1, comprising the following phases: measurement of the tensional state exerted by the user sitting on a counter surface corresponding to the upper surface of the support to be made in order to generate a first set of signals, translation of said first set of signals in a first set of data in order to provide a map of said tensional state, processing of said first set of data to generate a second set of data defining the spatial distribution of isostress lines corresponding to said tensional state,

distribution of a plurality of filiform strengthening elements along said isostress lines, forming of a substantially continuous resinous matrix comprising said filiform strengthening elements to define a finished support with pre-defined mechanical characteristics and weight.

According to the invention, the deposition phase is assured by coupling said plurality of filiform strengthening elements to a laminar element in order to form a semifinished product with a surface extension at least equal to the finished support, each filiform strengthening element being selected from those comprising a bundle of natural or synthetic fibres in which a plurality of non-polymerised resinous elements are distributed destined to define, once polymerised, said resinous matrix.

Furthermore a processing phase is provided for the second set of data and the calculation of a third set of data that defines the strictly needed quantity of resinous elements to be associated with said strengthening elements to form the finished support with the pre-defined characteristics.

It should be noted that in this text the term "isostress lines" refers to the directions along which the maximum tensional stress is produced on an elastic support under given load conditions.

Thanks to this particular configuration, the method according to the invention assures the customised production of the elastic support, allowing its mechanical characteristics to be adapted to the specific stress transmitted by each individual user.

Furthermore, the quantity of resin used will be only that which is strictly necessary, allowing the production of a particularly light and relatively cheap elastic support.

According to a further aspect of the invention, an apparatus is provided for the production of elastic supports for the human body according to claim 12.

Brief description of the drawings

Further characteristics and advantages of this invention will become clearer in the light of the detailed description of a form of preferred, but not exclusive, embodiment of a method and an apparatus for the production of elastic supports for the human body according to the invention, illustrated by, merely as an example and not limited to, the attached drawings in which:

FIG. 1 is a block diagram of a method according to the invention;

FIG. 2 is a schematic illustration of an apparatus according to the invention. Detailed description of an example of preferred embodiment

Referring to the aforementioned figures, the method and the apparatus according to the invention will be particularly useful for the production of integral elastic supports for the human body of the type constituted by a substantially continuous resinous matrix with which a plurality of strengthening fibres are associated.

In particular, the method and the apparatus according to the invention can be used to produce seat structures such as frames for bicycle or motorcycle saddles or bearing structures for chairs or vehicle seats.

As illustrated in the block diagram in Fig. 1, the method according to the invention comprises, not necessarily in a sequential manner, a phase a) to measure the tensional state exerted by the user sitting on a counter surface 10 corresponding to the upper surface of the support E to be produced in order to generate a set of signals S, a phase b) to translate the set of signals S in a first set of data D ₁ , to provide a map of the tensional state transmitted by the user's body to the counter surface 10 and which will substantially correspond to the tensional state of the finished elastic support E in one or more load conditions.

The method also comprises a phase c) to process the first set of data D ₁ , to generate a second set of data D ₂ defining the final geometry of the elastic support E and the spatial distribution of the isostress lines associated with the measured tensional state.

There is also a phase d) to stably deposit a plurality of filiform strengthening elements, not illustrated, and a phase e) to form a substantially continuous resinous matrix comprising the filiform strengthening elements in order to produce a finished support E with pre-defined, optimised mechanical and weight characteristics depending on the tensional state transmitted by the specific user for whom the support E is being intended to.

According to a particular characteristic of this invention, the phase d) to stably deposit the filiform strengthening elements is done by coupling the latter to a laminar element made of flexible material in order to form a semi-finished product 17 with a surface extension that is at least equal to that of the finished elastic support E.

Furthermore, each filiform strengthening element is selected from those comprising a bundle of natural or synthetic fibres in which a plurality of non-polymerised resinous elements is distributed in order to define, once polymerised, the resinous matrix.

To this end, a phase f) is also provided to process the second set of data D ₂ and calculate a third set of data D ₃ defining the quantity of filiform strengthening elements to be arranged and the strictly required quantity of resinous elements to be associated with the strengthening elements to form the finished elastic support E with the pre-defined characteristics.

In this way the produced elastic support E will present customised mechanical and weight characteristics to suit the real needs of the end user.

Therefore, the finished elastic support E will be of a notably lesser weight as it will not have been necessary to use a greater quantity of resin than that which was effectively needed to assure the required mechanical characteristics.

In fact, the arrangement of a quantity of strengthening elements as well as the controlled distribution of the resin will avoid the use of excess quantities of material.

Furthermore, the need to inject the resin into a mould in a quantity that is generally greater than the amount strictly needed will be avoided, to assure that the resin is full spread around the strengthening fibres even in the central area of the mould.

Advantageously, the phase a) could be done using a first electronic processor 11 configured to generate the set of signals S while the phase b) for the translation and c) processing can be done using a second electronic processor 13 connected to the first processor 11 by way of a telematic data transmission network 12 of the type of the internet, intranet or the like.

According to a preferred embodiment of this invention, the resin may be a thermoplastic resin in the form of particles or filaments in the solid state selected with an average diameter of between 1 μm and 10 μm and distributed among the strengthening fibres in a substantially uniform manner.

In turn the strengthening fibres could be of either synthetic or natural materials, such as fibreglass, kevlar, carbon, or fibres in natural fabric and may have an average diameter of between 1 μm and 10 μm.

Preferably, the bundle of fibres associated with the resin particles and/or filaments may be inserted in a flexible tubular sheath, also made preferably of thermoplastic resin, with a substantially constant diameter of between 1 and 100 μm.

Therefore, the strengthening fibres may define a single bundle inserted in the sheath and inside which the resin particles or filaments are distributed.

The material forming the resinous elements and the sheath may be a polymer resin selected from the group comprising polyethylene, polyurethane, polypropylene, polyvinyl or similar resins. Furthermore, the resinous elements may be formed of a material that does not necessarily coincide with the sheath material.

However, it will be possible to use any other resinous material of a known type, possibly even of a thermo-hardening type, depending on the characteristics to be obtained.

In addition, the non-polymerised resinous elements may be distributed among the strengthening fibres in the bundle according to a spatial distribution calculated in a further phase g) to process the second set of data D ₂ .

In this way, the forming phase e) can be done by the localised deposition of resin that is not yet polymerised on the laminar element and near the plurality of strengthening fibres, according to the distribution calculated in the phase g).

According to a preferred by not exclusive embodiment of the method described in this invention, the phase g) of the localised deposition of resin may be done at the same time as the phase d) to couple the strengthening fibres to the laminar element.

In this way it will be possible to further reduce the production times and at the same time guarantee greater penetration of the resin into the spaces defined between each strengthening fibre.

Whatever the method used for the application of the filiform strengthening elements on the laminar element, these may comprise one or more fibres or threads in an electrically conductive and/or shape-memorising polymer, e.g. of the polyurethane based type.

In this way, by connecting the elastic support E to a heat source, such as an electrical resistance, it is possible to modify the properties of the fibres in order to change

as required the mechanical characteristics of the whole support E adapting them on a case- by-case basis to a specific situation or operational condition.

Before the forming phase e), it is also possible to have a pre-shaping phase e') of the laminar element associated with the plurality of strengthening fibres in order to obtain a semi-finished product 17 with an external profile that is substantially close to the profile of the finished elastic support E.

For this purpose, the laminar element will preferably be in extremely lightweight flexible material for which no specific mechanical properties are required, as its purpose is simply to assure the mechanical distribution of the strengthening fibres.

For example, the laminar element may be made of paper, fabric or the like or in thermoplastic polymeric material that contributes to forming the matrix.

Advantageously, the phase d) to stably deposit the filiform strengthening elements on the laminar element may be done by sewing, gluing or any other type of known mechanical coupling.

According to a preferred embodiment of the invention, the continuous matrix forming phase e) may comprise an initial phase C ₁ ) to prepare a mould 19 with a central closed cavity 25 of a form that substantially corresponds to the form of the finished elastic support E and a following phase ei) to insert the semi-finished product 17, which may have been pre-shaped, into this cavity 25.

Preferably, but not exclusively, the insertion of the semi -finished product 17 into the mould 19 will be done in such a way that the surface destined to face the user comes into contact with the bottom of cavity 25.

The forming phase e) will be completed with a phase e$) to close the mould 19 which will in turn be followed by a resin polymerisation phase e ₄ ), e.g. through the

controlled heating of the mould 19 in order to determine the fusion of the resin and its spread throughout the strengthening fibres.

For this purpose, the use of a thermoplastic resin will offer the further advantage of requiring relatively low temperatures and shorter polymerisation times.

The method may also comprise one or more further phases of a known type for the production, starting with the finished support E, of a complete seat.

Fig. 2 illustrates an apparatus according to the invention, indicated overall with reference 1, for the execution of the above-described method, comprising a first computerised logic unit 2, on which a first programme 3 is installed, configured to acquire a set of input signals S relative to a tensional state intended for a finished elastic support E and to generate a first set of output data Di, and a second computerised logic unit 4 connected to the first unit 2 and on which a second programme 5 is installed for the processing of the first set of data Di, and the generation of a second set of data D ₂ defining the final geometry of the elastic support E and the quantity of filiform strengthening elements to be distributed on the laminar element, not illustrated.

The second logic unit 4 is connected electronically to an automated work station 6 configured to distribute the filiform strengthening elements in the calculated quantity on the laminar element according to the defined distribution map.

According to a particular characteristic of the invention, on the second computerised logic unit 4 a third programme 7 is installed that is configured to process the first set of data D ₁ , and calculate the minimum quantity of strengthening fibres to be distributed together with the strengthening elements and the quantity of resin to be associated with the filiform strengthening elements in order to obtain a support E with preset mechanical characteristics, minimising the consumption of resin at the same time.

According to a preferred, but not exclusive, embodiment of the invention, the apparatus 1 may comprise a measuring station 8 to measure the estimated tensional stress that may be exerted on the finished elastic support E in one or more operational conditions.

In one possible operational situation, the measuring station 8 may be used to measure the map of the directions along which the maximum tensional stress is produced

by a specific user in one or more conditions of use, generally under the heaviest load conditions.

In particular, the measuring station 8 may comprise a test elastic support 9 with a counter surface 10 defining a seat for the body of a user in various operational conditions.

A number of sensors, not illustrated, are distributed over the counter surface 10, intended to measure the tensional state transmitted by a user to the test support 9 and connected to a series of transducers, also not illustrated, as these are of common production.

The latter are connected to a first processor 11 which is an integral part of the measuring station 8 and adapted to generate the first set of data Di.

Thanks to the latter characteristic, it will be possible to obtain an elastic support E configured to match the anatomy and particular methods of use of each user, in an extremely customisable manner.

The measuring station 8 may be connected to the first computerised logic unit 2 through a telematic network 12 for exchanging data, such as the internet, intranet or the like, either by cable or in wireless mode.

Therefore, the measuring station 8 may also be located remotely to the rest of the apparatus 1 to which it may be connected through the telematic network 12, in the same way the apparatus 1 may be remotely connected to a potentially infinite number of measuring stations 8, 8', 8", ...

Furthermore, the first and second logic units 2, 4 may reside on the same electronic processor 13 connected to the measuring station 8 through the telematic network 12.

The work station 6 may comprise a computerised control unit 14, on which a fourth programme 15 is installed to process the second and third sets of data D ₂ , D ₃ and a mechanical operational unit 16 managed by the control unit 14.

The second computerised logic unit 4 will be connected to the control unit 14 of the work station 6, e.g. an appropriately programmed ordinary PLC configured to guide the mechanical operational unit 16 according to the spatial distribution of the filiform strengthening elements calculated by the second logic unit 4 on the basis of the data acquired and transmitted by the measuring station 8.

In an advantageous embodiment, not illustrated in detail, the mechanical operational unit 16 may also comprise a support surface for the laminar element and a plurality of sewing heads placed above the support surface and controlled by the control logic unit 14 that is appropriately programmed to distribute the plurality of strengthening elements on the laminar element.

The mechanical operational unit 16 may be equipped with suitable cutting means, not illustrated as of a known type, to carry out the pre-shaping phase e') of the semifinished product 17 composed of the laminar element coupled to the strengthening elements, in such a way as to present a profile which, apart from an edge portion 18, if any, will be substantially similar to the profile of the finished elastic support E.

Furthermore, the apparatus 1 may comprise a mould 19 which has a female element 20 with an open central cavity 21 of a shape that substantially coincides with the final shape of the elastic support E and with which, in a manner that is per se known, heating means 22 may be associated that are suitable for promoting the fusion and polymerisation of the resin distributed among the fibres.

Furthermore, the mould 19 may comprise a male element 23 which has a central protrusion 24 of a shape that is substantially complementary to that of the central cavity 21 of the female element 20 in such a way as to interact with it and define the closed cavity 25 destined to contain the semi-finished product 17.

Preferably, the protrusion 24 of the male element 23 may be at least partially made in a highly malleable material selected from the group comprising silicon materials and the like. In particular, the portion in silicon material may correspond to at least the surface 26 of the protrusion destined to come into contact with the semi-finished product 17.

In this way the male element 23 of the mould 19 will maintain the distribution of fibres substantially unaltered and furthermore the mould 19 will be notably cheaper.

The apparatus 1 may be integrated within a production line, e.g. a line of the carousel type described in European patent EP 0653279 131 and therefore not illustrated, which may comprise a plurality of moulds 19, not necessarily all similar.

In this way it will be possible to carry out, in an automated and continuous manner, all the phases required for the production of seats for the human body, including saddles,

chairs and seats, comprising an elastic support E produced using the apparatus and/or in accordance with the method described in this invention.

For example, the semi-finished product 17 may be inserted in the mould 19 to be processed according to the method described in order to produce the finished support E and to which if required further padding may later be associated, in foam material, gel or the like, and a cover or any other element required to complete the seat.

From the above description it appears evident that the invention achieves the set objects and in particular that of providing a method and an apparatus for the production of highly customisable elastic supports for the human body with greatly reduced weights and production costs.

The method and the apparatus according to the invention are susceptible to numerous modifications and variants, all of which fall within the concepts of the invention expressed in the attached claims. All the details may be replaced by other technically equivalent elements and the materials may differ according to need, without falling outside the scope of this invention.

Although the method and the apparatus are described with particular reference to the enclosed figures, the reference numbers used in the description and the claims are used to improve the understanding of the invention and shall not constitute any limitation in the field of the protected claim.