The present invention relates to a method of using a disposable pin for the positioning and production of parts made of composite material and glued together used in tools for lamination and gluing of aircraft parts. Document US 2008/0298927 A1
shows an example of a positioning pin.
Tools for production of parts made of composite materials or glued together for aircraft are substantially cradles that contain the various parts of an group during the assembly step of a group itself. Said cradles form seats for precise positioning of the various parts so as to favour proper constraint thereof to the other parts of the group itself resting on the cradle.
It is known that in a cradle in which a part of an aircraft is housed both in the assembly step and for checks for setting-up and routine monitoring of the aircraft, pins are used for positioning and provisionally fixing loose or preassembled parts of the aircraft both during the assembly step and during setting-up of the aircraft itself.
The pins are inserted into purposely provided holes arranged in key points of the parts where a temporary fixing is necessary. During the step of production of parts made of composite materials, the pins create, where they are positioned, holes for future references for the assembly step on subsequent frames for assembly of the aircraft itself.
The pins notoriously comprise two parts: a cylindrical body and a head. According to the known art the aforesaid pins are made of resistant materials of a metal type or a plastic type, for example Teflon, and the process for the production of said pins comprises, amongst other things, a step of turnery of the aforementioned materials.
As known to the person skilled in the art, said step of the process entails very long and costly production times. Furthermore, the use of metal materials for making said pin can damage the structure of the aircraft when the pin is totally inserted into the holes, because of relative movements between the structures of the frame or else on account of an incorrect insertion of the pin into the hole by the operator.
It should moreover be emphasized that said pins are used for fastening materials with different physical characteristics.
During the steps of polymerisation, usually hot polymerisation, with a thermal delta even of 170°C, different degrees of thermal expansion are produced between the various components or between the components of aircraft structures and the polymerisation cradles, according to their own coefficients of thermal expansion, which put said pins to non-negligible forces, due to the relative movements between the parts or between the parts and the equipment.
Said forces can also cause deformation of the engagement hole with consequent deformation also of said pins, making them difficult to extract and no longer further usable.
As in the production of an aircraft said pins are used in a wide range of production steps, the aforementioned problem leads to an increase in the costs caused, very frequently, by the unusability of pins already adopted in the previous steps of production of the component and of the aircraft itself.
Extraction of said pins, once they have been inserted into the reference holes, is complex and can be at times particularly difficult, and in some cases can lead indirectly to damage of the tool itself.
The known art does not provide a satisfactory solution and, it is necessary to rely only upon the experience of the operators for carrying out said operation.
The purpose of the present invention is to overcome said drawbacks by creating a new type of disposable pin made of reinforced thermoplastic material obtained using a die that enables a very fast, reliable, and low-cost production process.
The use of a thermoplastic material moreover enables said pin to undergo deformation according to the deviations of the hole in which it is inserted. The low cost of said pins means that it is no longer necessary to be concerned either upon the possible deformations undergone during its use or upon extraction of the pin itself.
Said new solution moreover enables application of a new method for facilitating extraction of said new pins after their use on frames by creating a hole within said pin.
One aspect of the present invention regards a method of using a pin for positioning of glued parts and composite parts that presents the characteristics specified in claim 1.
Further accessory characteristics are contained in the annexed dependent claims.
The characteristics and advantages of said pin will emerge more clearly and evidently from the ensuing description of an embodiment thereof, with reference to the attached figures, wherein specifically:
- Figure 1 is a perspective view of a pin according to the present invention; and
- Figure 2 shows the pin of Figure 1 in a longitudinal section.
With reference to the aforesaid figures, the present invention regards a disposable pin made of reinforced thermoplastic material, which comprises an elongated, preferably cylindrical, body 1, which is inserted into the holes purposely provided on the parts of the aircraft or of the assembly jig, and a head 2, which limits insertion of the pin in the aforesaid holes.
In the embodiment illustrated, the pin comprises the aforesaid cylindrical body 1 and head 2, made of one and the same material and obtained with a single production process. The pin as a whole is traversed longitudinally by a through hole 4.
Elongated body 1 is adapted to be inserted into the holes for positioning the parts during assemblage of the aircraft.
Provided in the bottom part of elongated body 1 is a tapering 3, for facilitating insertion of the pin within the purposely provided holes.
Head 2 positioned in the top part of body 1 has its ends chamfered so as not to ruin the parts of the aircraft that are to be assembled. In the stage of production of the parts made of composite material, after removal of the cylindrical body, head 2 reinforces the seat of the hole. Through hole 4 is positioned along the vertical axis, centred with respect to the axis of the pin.
Said hole 4 is adapted to facilitate extraction of said pin.
It should be emphasized how the method for production of the pins by turning according to the known art does not enable a hole 4 to be made directly in the pin, other than at sustained costs, unlike the mould method used by the present invention.
The material of which the pin is made is a thermoplastic material or else equivalent materials with which said pin can be obtained with a moulding process, in particular injection moulding.
To render said production process even more advantageous, it may be added for information purposes that it is expedient to use thermoplastic materials adapted for the aforementioned applications but with not excessively high melting points.
The dimensions of the cylindrical body, of the head, and of the hole are dictated by the standards for such a pin according to the parts that are to be provisionally fixed using said pin.
The injection-moulding technique enables creation of a large number of pins simultaneously with a low cost and at a high speed, maintaining the reliability of the pin itself unaltered.
To facilitate extraction of the pin from the hole after its use, the aforesaid through hole 4 is created, but it is possible to obtain an advantage for extraction also from a simple non-through hole.
The method of extraction used consists in cleaning the hole in which the pin is inserted via a drill of adequate size, without any damage to the parts of the aircraft.
With said method the technical problem of extraction of the pin when it is deformed and cannot be extracted in a simple way is solved.
The function of said hole is hence that of guide for the drill that is to clean said hole and to reduce the amount of material used for the production of the pin, and as the diameter thereof is varied the co-operating section of the pin itself varies accordingly.
The method for cleaning the hole in which the pin is inserted can be obtained with systems equivalent to what has just been described.
Tapering 5 can be more or less accentuated according to the requirements of use of said pin.
The shape of head 3 described is circular in shape but it may have a different shape, for example, in compliance with the standards ISO 261 and ISO 262 for bolts.
A method of using a disposable pin for the production and positioning of parts made of composite material and glued together of an aircraft, said pin being produced by a moulding process and comprising an elongated body (1) and a head integrated in a single body made of a reinforced thermoplastic material in a single molding step, said pin being traversed longitudinally by a through hole along the vertical axis of said pin; said method comprising:
- providing a hole on the parts of the aircraft or of the assembly jig;
- inserting the elongated body (1) of the pin in said hole, so that the head (2) limits the insertion of the pin in the aforesaid hole;
- polymerizing the parts of the aircraft or the assembly jig;
- extracting said pin by cleaning said hole with a drill guided by means of said through hole.
2. Method according to claim 1, wherein the production process is a process of injection moulding.
3. Method according to claim 1, wherein the hole (4) is created during the same process of production of the pin.
4. Method according to claim 1, wherein a tapering (3) is comprised in the bottom part of the elongated body (1).
5. Method according to claim 1, wherein the elongated body is cylindrical.
6. Method according to claim 1, which as a result of the material of which it is made and of the through hole that adjusts the co-operating section thereof, it collapses transversely in the presence of shearing loads, thus safeguarding the structural integrity of the equipment and of the aircraft structure.
Verfahren zur Verwendung eines Einwegstiftes für die Herstellung und Positionierung von Teilen aus Verbundmaterial, die durch einen Formprozess hergestellt und miteinander verklebt werden, wobei der Stift durch einen Urformprozess hergestellt wird und einen länglichen Körper (1) und einen Kopf aufweist, die in einem einteiligen Körper integriert sind, ausgeformt aus einem verstärkten thermoplastischen Material in einem einzelnen Urformschritt, wobei ein Durchgangsloch in Längsrichtung den Stift durchstößt entlang der vertikalen Achse des Stiftes; wobei das Verfahren aufweist:
- Bereitstellen eines Lochs an den Teilen des Flugzeugs oder der Montagevorrichtung;
- Einsetzen des länglichen Körpers (1) des Stiftes in das Loch, so dass der Kopf (2) das Einsetzen des Stiftes in das vorgenannte Loch begrenzt;
- Polymerisieren der Teile des Flugzeugs oder der Montagevorrichtung;
- Herausziehen des Stiftes durch Ausputzen des Lochs mit einem Bohrer, der mittels des Durchgangslochs geführt wird.
2. Verfahren nach Anspruch 1, wobei das Herstellungsverfahren ein Spritzgießverfahren ist.
3. Verfahren nach Anspruch 1, wobei das Loch (4) während des gleichen Prozesses zur Herstellung des Stiftes erzeugt wird.
4. Verfahren nach Anspruch 1, wobei eine Verjüngung (3) im unteren Teil des länglichen Körpers (1) enthalten ist.
5. Verfahren nach Anspruch 1, wobei der längliche Körper zylindrisch ist.
6. Verfahren nach Anspruch 1, welches als ein Ergebnis des Materials aus welchem es hergestellt ist und von dem Durchgangsloch das den zusammenwirkenden Abschnitt davon anpasst, es bei Scherkräften in Querrichtung zusammenbricht, und somit die strukturelle Integrität der Ausrüstung und der Flugzeugstruktur gewährleistet.
Procédé d'utilisation d'une broche jetable pour la production et le positionnement de pièces, constituées d'un matériau composite et collées ensemble, d'un aéronef, ladite broche étant produite par un processus de moulage et comprenant un corps allongé (1) et une tête intégrée dans un corps unique constitué d'un matériau thermoplastique renforcé dans une étape de moulage unique, ladite broche étant traversée longitudinalement par un trou traversant le long de l'axe vertical de ladite broche ; ledit procédé comprenant :
- la fourniture d'un trou sur les pièces de l'aéronef ou du gabarit d'assemblage ;
- l'insertion du corps allongé (1) de la broche dans ledit trou, de sorte que la tête (2) limite l'insertion de la broche dans le trou susmentionné ;
- la polymérisation des pièces de l'aéronef ou du gabarit d'assemblage ;
- l'extraction de ladite broche par le nettoyage dudit trou avec un foret guidé au moyen dudit trou traversant.
2. Procédé selon la revendication 1, dans lequel le processus de production est un processus de moulage par injection.
3. Procédé selon la revendication 1, dans lequel le trou (4) est créé au cours du même processus de production de la broche.
4. Procédé selon la revendication 1, dans lequel un effilement (3) est compris dans la partie inférieure du corps allongé (1).
5. Procédé selon la revendication 1, dans lequel le corps allongé est cylindrique.
6. Procédé selon la revendication 1, dans lequel, sous l'effet du matériau la constituant et du trou traversant qui ajuste la section de coopération de celle-ci, elle s'affaisse transversalement en présence de charges de cisaillement, protégeant ainsi l'intégrité structurelle de l'équipement et de la structure de l'aéronef.