ITUD20110111A1 - ROLLER IN THREADED COMPOSITE MATERIAL AND ITS CONSTRUCTION PROCEDURE - Google Patents

Description

Description of the invention having as title:

"ROLL IN COMPOSITE THREADED MATERIAL AND RELATIVE PROCESS OF REALIZATION"

FIELD OF APPLICATION

The present invention refers to a roller, or tube, made of composite material, in particular carbon fiber or glass or glass / carbon produced with the mandrel wrapping or tape winding process, which, suitably threaded near its ends, is associated with nuts, or bushings, also threaded and thus joined also with the use of glues.

STATE OF THE TECHNIQUE

Rollers made of composite material are known which are associated with nuts or bushings made both of composite material and of metal. Said nuts, or bushings, can be associated with the rollers, or tubes, by means of known types of glue, or by screwing if they are threaded.

In the first case, the known art presents some application difficulties. The glues have an optimal seal only if the surfaces are perfectly clean in order to avoid both their parts being glue-free, or having an abundance of it, which would lead to a different resistance of the pieces - to the pressures and / or tractions to which they are subjected - unevenly.

Another problem of this known technique is that on the whole part of the surfaces involved in the coupling, no air bubbles must be present, which entails both an absence of glue and a different cooperation and resistance of the associated materials.

Yet another problem of this known technique, for rollers or tubes with bushings equipped with a cap or shoulder, is that said rollers and said bushings, in the terminal part that abut one with the other, must be cut in such a way that said stop does not have interruptions or jumps, that is to say that they have perfectly orthogonal axes, this in order to optimize the tightness of the coupling and to keep the two elements thus coupled in axis. Despite this expedient of orthogonal cutting of the tube to its axis, the coaxiality between the fiber roller and the metal bushing is not guaranteed.

The second known technique (threading) is currently applied only to rollers produced with the pultruded or filament winding production technique.

Still with reference to this known technique, in all the production processes used to make composite rolls, or tubes and which are mechanically processed to make threads, the threads of the fiber are sheared which - in the production phase - are affixed longitudinally to the axis of the roller or tube or with an angle of the laying of the fiber greater than that of the pitch of the thread itself.

Thus not all the thicknesses, that is the layers of the composite of said rollers, or tubes, can be used for coupling with nuts, or bushings, also made of other material and not only composite, but present the constant problem of weakening structure of the composite pipe in the area where the threads are created, regardless of the thickness of the pipe. The elements defined by the set of tubes and bushings when subjected to different pressures or tractions or stresses which, due to the thickness of the tube itself, could withstand, burst, or in any case break due to the mechanical processing used for threading. Or they require pipes with much greater thicknesses to be used due to the pressure or traction to which it must be subjected, thus imposing at least higher costs, calculations that cannot be controlled for the safety of the final product, larger dimensions.

An object of the present invention is to provide a roller, or tube, in composite material, produced in mandrel wrapping or tape winding with fibers arranged mainly circumferentially with respect to the axis of the tube, in the area involved in mechanical processing, to create threads, which also develop according to a circumferential development, near at least one of its vertex in order to be associated by screwing with a nut, or bush, also made of a material different from the composite one so as to allow the desired seal for any pressure or pull.

Said solution can also be supplemented by suitable gluing of the bushing to the pipe.

In order to obviate the drawbacks of the known art and to obtain this and further objects and advantages, the Applicant has studied, tested and implemented the present invention.

EXPOSURE OF THE FOUND

The present invention is expressed and characterized in the independent claims.

The secondary claims disclose other characteristics of the present invention or variants of the main solution idea.

In accordance with the aforementioned purpose, a roller or tube made of mandrel wrapping or tape winding has been designed and prototyped which, in proximity to at least one area affected by the thread, has fibers arranged mainly circumferentially with respect to the axis of the tube, or roller. , same.

The presence of fibers arranged in this way allows not to interrupt, and therefore increase, the structural seal of the tube, or roller, in the area of the thread since the fibers of the composite material used are no longer engraved due to the mechanical processing necessary to create said thread. .

In particular, the present invention underlies a preferential relationship as specified below in the area of the pipe involved in the thread:

ST = SC SL

where is it :

ST = is the thickness of the tube;

SC = is the thickness of the portion of ST of circumferential fibers composed of SF an additional minimum of 0.2mm of circumferential fibers;

SF = is the thickness of the thread, ranging from a minimum of 0.02 to a maximum of 0.5 times ST; SL = longitudinal fiber thickness;

and where

SC can be equal to ST, which implies the absence or presence in small parts of longitudinal fibers at least in the area involved in the thread.

In particular, according to advantageous embodiments it can be provided that in said area affected by the thread, the circumferential fibers are at least 50% of the remaining preferential embodiments, in said area, the presence of circumferential fibers is at least 70% of the remaining fibers. In even more preferential embodiments, in said zone, the presence of circumferential fibers is at least 90% of the remaining fibers.

In even more preferential embodiments, only circumferential fibers are present in said zone.

With reference to what has been said above, the remaining fibers can have a substantially longitudinal development along the extension of the roller or they can also extend in further directions.

The thread will therefore have a depth that is always less than the thickness of the tube substantially composed of circumferentially arranged fibers. Said circumferential fibers will be mainly disposed towards the surface, internal or external, of the tube, or roller, which has the thread.

When said circumferential fibers cooperate with the longitudinal fibers - in the area affected by the threading - the latter are placed either above or below the layers of circumferential fibers where the threading takes place.

The fact that a plurality of fibers placed circumferentially in the vicinity of the area affected by the thread, means that the latter does not interrupt the structural seal given by the circumferential fibers - as occurs in the case of longitudinal fibers - and allows the roller, or tube, to couple to the nut or bushing in an appropriate way without the possibility of breakage.

Another advantage of the present invention is that the mechanical processing suitable for creating the thread causes the nut or bush to come into direct contact with the intact or substantially intact fibers, without the interruption represented by the intermediate layer defined by the own resin of all composite materials which, thanks to the thread, is removed and leaves the fibers uncovered. This arrangement means that the resin is not an element of transmission of the traction or pressure to which the tube is concerned, and that said forces are directly discharged at least on the circumferential fibers so as to be better distributed and not to create the known breaks in the products belonging to the state of the art.

Another advantage of the present invention is that the possible application of known glue in the area affected by the thread improves the sealing capacity of the product thus made, it does not limit it as in the known art. In fact, the thread, or rather the screwing of the nut / bushing onto the roller, ensures that the glue is evenly distributed even in direct contact with the intact or substantially intact fibers, at least in the threaded area and also helps to avoid the deflection of the nut / bushing.

Made in this way, the product ensures that the pressure, or traction to which it is subjected is distributed directly at least to the circumferential fibers and is uniformly distributed on the tube itself which in this case - as in the case of the nut screwed onto the roller without glue - does not have interruptions in the its structure.

The thread in the tube can be both external and internal and in this case the nut or bushing will be respectively screwed to the outside or inside of the tube.

As mentioned above, in the case in which the thread is present outside the tube, the circumferential fibers will be arranged near the external surface of the tube, vice versa, in the case in which the thread is present inside the tube. A tube as described is made on a male mandrel according to the known technique, but which is improved in an innovative sense since near the vertices of the tube, or roller - during the coupling phase of the fibers of composite material such as carbon or glass or glass and carbon - some layers are arranged in such a way that the fibers are circumferential with respect to the axis of the tube, or roll.

The depth of the circumferential fibers and / or their presence towards the internal or external surface, or towards both surfaces of the tube, or roller, depends on the thickness of the tube and on the function it is intended for.

For rollers or tubes with bushings equipped with a cap or shoulder and threaded fastening system, the perpendicular cut of the tube to its axis guarantees the coaxial connection between the fiber roller and the metal bush.

ILLUSTRATION OF DRAWINGS

These and other characteristics of the present invention will become clear from the following description of preferential embodiments, provided by way of non-limiting example, with reference to the attached drawings in which:

fig. 1 is a sectional view of a threaded composite material roller according to the present invention;

fig. 2 is a view of a variant of fig.

fig. 3 is an enlarged view of a detail of fig. 2;

fig. 4 is a view of a variant of fig

- fig. 5 is a sectional view of fig. 4 along the IV-IV line.

DESCRIPTION OF SOME PREFERENTIAL FORMS OF REA-

LIZATION OF THE FOUND

With reference to fig. 1, a roller made of threaded composite material is indicated as a whole with the reference number 10, and comprises a tubular body 13, hollow internally to define an external surface 11 and an internal surface 12

The tubular body 13 has an end 15 provided, on the internal surface 12, with a threaded portion 16 which extends to the terminal edge of the tubular body 13.

A threaded element is associated with the threaded portion 16, in this case a bushing 17, of the male type, suitable for supporting any accessory elements, in this case a bearing 18.

In particular, the bush 17 is provided on its external surface with a threaded portion suitable to be screwed into the threaded portion 16 of the bush 17.

The bush 17 is provided with a shoulder 19 which, in use, abuts against the terminal edge of the tubular body 13.

To ensure coaxiality between the tubular body 13 and the bushing 17, the terminal edge of the end 15 of the tubular body 13 must be substantially coplanar with the abutment surface of the shoulder 19 of the bushing 17. This allows to avoid axial misalignments between the tubular body. 13 and bushing 17, and to obtain a balanced roller 10.

In another embodiment (fig. 2), the threaded portion is indicated with the reference number 116 and instead of being formed on the internal surface 12 of the tubular body 13 it is formed on the external surface 11.

The threaded portion 116 is adapted to allow the connection of a threaded element, in this case a nut 170 substantially shaped like a cap which closes the end 15 defining with the internal surface 12 a substantially closed cavity.

The tubular body 13 (Fig. 3) is made of a composite material selected from a group comprising glass fibers, carbon fibers, glass and carbon fibers or the like.

The threaded elements, that is the bushing 17 (fig. 1) or the nut 170 (fig. 2) can also be made with composite material or with metallic materials such as steel, aluminum, titanium or similar and similar materials.

The tubular body 13 has a thickness ST which determines the mechanical resistance of the roller 10 to loads of pressure, traction to which it will be subjected. The threaded portion 116 has a profile of the thread 23 having a height, or thickness of the thread SF, which is a function of the external diameter of the tubular body 13, and of the type of thread to be made.

It is also advantageous to provide that the thickness of the threads SF is between about 0.02 and about 0.5 times the thickness of the tube ST, that is:

0.02 ST <SF <0.5 ST

At least the end 15 of the tubular body 13 is provided with at least a first zone 21 arranged in proximity to the aforementioned threaded portion 116, more external provided with a plurality of fibers which extend / wind along a circumferential direction C (fig. 5), of the tubular body 13 and hereinafter referred to as circumferential fibers 25, and of at least a second zone 22 (fig. 3), more internal than the first zone 21, provided with a plurality of fibers which develop along a longitudinal direction (L) , hereinafter referred to as longitudinal fibers 26.

The first zone 21 and the second zone 22 have, in this case, a circular crown shape and have respectively a thickness SC and a thickness SL.

In particular, in the section between the threaded portion 116, the relation is expected to be valid:

ST = SC SL

The thickness SC of the first zone 21 is greater than the thickness of the thread SF by at least one additional thickness SA.

The additional thickness SA is at least greater than 0.2 mm, preferably greater than the thickness of the circumferential fibers 25.

Consequently, the relationship is valid:

SC = SF SA

In advantageous embodiments (Figs. 4 and 5), the second zone 22 can be provided with both longitudinal fibers 25 and circumferential fibers 26; in this way it is possible to give the tubular body 13 greater mechanical strength.

In still other embodiments, it can be envisaged that in the second zone 22, in addition to circumferential fibers and longitudinal fibers, there are fibers which extend in other directions.

Similarly, the first zone can also present, in addition to the circumferential fibers 25, also fibers which extend in other directions, for example longitudinal. The fibers arranged in a non-circumferential direction in this case act as a filling with the other fibers, and even if they are interrupted during the threading phase, the resistance of the latter is guaranteed by the presence of the circumferential fibers 25.

In this case it is however advantageous to provide that at least 50%, preferably 70%, even more preferably 90%, are circumferential fibers 25, with respect to the total fibers. It is evident that a dual arrangement of the first 21 and of the second zone 22 is also provided for the case shown in fig. 1, or providing that the first zone 21 is arranged substantially in proximity to the internal surface 12 of the tubular body 13, at least where the threaded portion 16 is present, and the second zone extends from the first zone 21 towards the external surface 11 of the tubular body 13.

Between the threaded portion 16 or 116 of the end 15 of the tubular body 13 and the threaded portion of the threaded element, or of the bush 17 or of the nut 170, when they are assembled together, a gap 28 is defined, at least between the ridges and the bottom of each thread, which are filled with a layer of glue 29 to prevent unwanted loosening of the threaded connection.

The present invention also relates to the related manufacturing process of the threaded composite material roller 10.

In particular, a first step is envisaged for manufacturing the tubular body 13 by means of techniques comprising at least mandrel wrapping and tape winding. During this phase, the material with which the tubular body 13 is made is arranged in a known way on a male mandrel defining both the first 21 and the second zone 22, that is, arranging both the circumferential fibers 25 and the radial ones 26 according to the methods described above.

The fibers 25, 26 are embedded in a polymeric material, or in thermosetting resins, which keep them linked together.

The tubular body 13 thus obtained is devoid of the threaded portion 15, and can also be subjected to treatments in a vacuum chamber to stabilize the polymerization of polymeric materials or thermosetting resins.

Subsequently, a second step is envisaged for producing the threaded portion 16, 116, near the end 15, by means of machining by removing material. During this phase the tool defines the profile of each thread by removing material from the first zone 21 for a thickness equal to the thickness SF.

Since the first zone 21 has only circumferential fibers 25, which are wound substantially in a manner coordinated with the development of the thread, the longitudinal fibers 25 are not interrupted by altering their structural strength. This results in a greater resistance of the threaded connection to both pressure and tensile loads to which the roller 10 can be subjected during use.

A third step is then provided in which the threaded element, bushing 17 or nut 170, are screwed into the threaded portion 16 respectively 116 to make their mutual connection.

During this third phase it is possible to provide that, before the mutual connection between the threaded element 17, 170 and the tubular body 13, a layer of glue 29 is spread on their portions to be joined.

In this way, during screwing in and after drying of the glue, their stable connection to each other is achieved.

It is also clear that, although the present invention has been described with reference to some specific examples, a person skilled in the art will certainly be able to realize many other equivalent shapes, having the characteristics expressed in the claims and therefore all falling within the scope of protection from they defined.

For example, it is possible to provide that, in embodiments, the portion of the tube close to the external surface 11, or internal 12 and arranged in the vicinity of the first zone 21 consisting of circumferential fibers 25, has an arrangement of the fibers different from the circumferential development, for example fibers arranged substantially longitudinally.

In this way, in fact, only the portion of the tube which is affected by the thread is provided with the first zone with circumferential fibers, while the remaining part can have fibers arranged in such a way as to optimize the mechanical characteristics of the roller 10 in these zones.

In other embodiments, the tubular body 13 is provided at both its ends with threaded portions obtained on respective first areas having the characteristics described above.

In this case it is advantageous to provide that the thread obtained at one end is opposite to the thread obtained at the other end, for example by providing a right-hand thread on one side and a left-hand thread on the other. In this way, the threaded elements which are screwed at both ends when rotated determine a self-locking of the threaded connection.

Claims (12)

CLAIMS 1. Roller in threaded composite material comprising at least one tubular body (13) made with techniques such as mandrel wrapping or tape winding and provided, near at least one of its ends (15), with a threaded portion (16; 116) obtained on the surface external (11) or internal (12) of said tubular body (13) and on which at least one threaded element (17; 170) is suitable to be screwed, characterized in that said end (15), at least in proximity to a first the area (21) affected by the thread comprises a plurality of circumferential fibers (25) which extend along a circumferential direction (C) of the tubular body (13). 2. Roller as in claim 1, characterized in that said first zone (21) is substantially shaped like a circular crown and has a thickness (SC) at least greater than the thickness (SF) of the profile of said threaded portion (16; 116) . 3. Roller as in claim 2, characterized in that said thickness (SC) of the first zone (21) is at least 0.2 mm greater than said thickness (SF) of the profile of said threaded portion (16; 116). 4. Roller as in claim 2 or 3, characterized in that said thickness (SF) of the profile of said threaded portion (16; 116) is comprised between about 0.02 and 0.5 times the thickness (ST) of said tubular body (13) . 5. Roller as in any one of the preceding claims, characterized in that said first zone (21) extends longitudinally substantially for the length of said threaded portion (16; 116). 6. Roller as in any one of the preceding claims, characterized in that in said first zone (21) said circumferential fibers (25) are at least 50%, preferably 70%, more preferably 90%, even more preferably 100 % of total fibers. 7. Roller as in any one of the preceding claims, characterized in that said fibers (25, 26) are selected from a group comprising glass fibers, carbon fibers or glass and carbon fibers. 8. Roller as in any one of the preceding claims, characterized in that between the threaded portion (16; 116) of said end (15) of the tubular body (13) and said threaded element (17; 170) a layer of glue (29) to join together said tubular body (13) and said threaded element (17; 170). 9. Roller as in any one of the preceding claims, characterized in that it further comprises at least a second zone (22) adjacent to the first zone (21) and provided with fibers extending mainly in the longitudinal direction and possibly in further directions. 10. Process for manufacturing a roller (10) in threaded composite material, comprising at least a first step of manufacturing a tubular body (13) by means of techniques such as mandrel wrapping or tape winding, a second step during which, at least in proximity of an end (15) of said tubular body (13), on its external (11) or internal (12) surface, a threaded portion (16, 116) and a third phase during which a threaded element (17 ; 170) is screwed into said threaded portion (16; 116), characterized in that in said second phase, at least in proximity to a first area (21) affected by the thread, a plurality of circumferential fibers (25) are arranged which extend along a circumferential direction (C) of said tubular body (13). 11. Process as in claim 10, characterized in that said threaded portion (16; 116) is made by removing material. 12. Process as in claim 10, or 11, characterized in that before said third step a layer of glue (29) is placed on said threaded portion (16; 116) and / or on said threaded element (17; 170) to make said tubular body (13) and said threaded element (17; 170) integral with each other.