Hose and capsule system

Abstract

The present invention is concerned with a system for installing fasteners in an aircraft structure. The system comprises a feeding station 2 comprising one or more fasteners 8, each fastener arranged

Description

FIELD AND BACKGROUND

[0001] The present invention relates particularly, but not exclusively, to an improved robot system for placement and installation of fasteners in aircraft structures. The robots may be light industrial robots, larger robots or collaborative robots, 'cobots'. Known cobots move at slow speed due to power and force limitations and for safety reasons. Furthermore, they can only move a small payload, for similar reasons. A significant portion of the total process time is spent by the whole cobot moving to pick up a fastener and then moving back in front of the product to install the fastener. This movement is repeated for each individual fastener. Since it is often necessary to install multiple fasteners in aircraft structures, this process takes a significant amount of time. Light industrial robots typically move faster than cobots, however they can only move a small payload and still take a significant portion of the total process time to pick up a fastener. Throughout the rest of the application, the term 'robot' is used to cover all of these types of robot, including cobots.

[0002] Additionally, in existing fastener installing robots, fasteners are delivered to an end effector without sealant, using pneumatic tubes. Once the fastener has been received by the end effector, sealant needs to be applied to the fastener before it is installed. This slows down the installation process. Additionally the process requires there to be multiple tubes, one for each fastener type and diameter, and a further component at the robot end effector to apply the sealant to the fastener, increasing weight, volume and complexity of the end effector. There is therefore a desire to speed up the installation of fasteners in applications such as aircraft structures.

[0003] The inventors have discovered a novel way of supplying the fasteners to the robot for placement and installation in the aircraft structure. The new apparatus and method developed by the inventors is estimated to approximately halve the process time for installing fasteners. Although the invention relates to a robot for placement and installation of fasteners in aircraft structures, as would be understood by the skilled person, the robot is useable in other applications where it is desirable to place and install small parts such as fasteners. For example, the invention could be used in non-aircraft related applications. As another example, the system could be used with a hand tool operated by a person. SUMMARY

[0004] Particular aspects and embodiments are set out in the appended claims.

[0005] Viewed from a first aspect, there is provided a system for installing fasteners in an aircraft structure. The system comprises a feeding station comprising one or more fasteners, each fastener arranged in a capsule, wherein at least part of each fastener is coated with sealant. The system further comprises an end effector station, a first tube configured to connect to the feeding station at a first end and to the end effector station at a second end and configured to transport capsules comprising the one or more fasteners coated with sealant from the feeding station to the end effector station. Further, the system comprises a second tube configured to connect to the feeding station at a first end and to an air supply and extraction system at a second end.

[0006] The robot end effector is attached to a robot arm. By transporting the fasteners with the sealant already attached, it is not necessary to have a sealant applying module on the robot end effector itself. This therefore reduces the weight of the end effector and the hoses attached to the robot arm. Therefore, the robot arm is more moveable. Furthermore, since the fastener is delivered directly to the end effector, the fasteners can be installed much quicker than if the end effector was required to itself collect the fasteners one by one from a feeding station. The first tube may be connected to the end effector station via a capsule receiving portion. The air supply system is able to supply air into the second tube and consequently into the first tube and also extract air from the first and second tubes. Although the system is typically used for installing fasteners in aircraft applications, it may also be used in non-aircraft based applications.

[0007] Each capsule may comprise a first holding mechanism for releasably attaching to a tip of the fastener. The first holding mechanism may be a compliant mechanism formed of a flexible material. By holding just a tip of the fastener, the sealant can be applied to the other end of the fastener so that the fastener can be transported with the sealant already coated on it. This also prevents the capsule itself being contaminated with sealant so that it can be reused. Furthermore, the fastener can be added to and removed from the capsule without removing the sealant. Since the first holding mechanism is formed of a flexible material, it is able to flex to receive or release the fastener. In other examples, rather than holding the tip of the fastener, the capsule may hold any part which is not coated in sealant.

[0008] Each capsule may additionally comprise a second holding mechanism configured to hold the fastener within the capsule as the capsule is transported along the first tube. The second holding mechanism may be inserted into the capsule after the fastener has been attached to the first holding mechanism.

[0009] The air supply and extraction system may comprise a compressed air and suction system configured to move a capsule of the one or more capsules comprising a fastener from the feeding station to the end effector station and configured to move the capsule back to the feeding station. The suction force may be applied by an existing air extraction device.

[0010] Specifically, a compressed air supply may be used to propel the capsule along the first tube so that it can be transported with the fastener coated with sealant to the end effector station. Once the fastener has been removed at the end effector station, the capsule is sucked back along the first tube using the suction system. For example, a partial vacuum pulls the capsule back to the feeding station.

[0011] The term 'compressed air and suction system' may also include: using compressed from a connector in the factory (possibly using pressure and flow regulators) or filling a reservoir with compressed air (e.g. with air from the factory) and then (through and actuated valve) letting this air flow into the hose to deliver the capsules. Alternative air supply systems can be used if no compressed air or air suction system is available or if connecting the system to a compressed air supply or air suction system is deemed impractical, for example when the system is mobile and a constant need for a connection to a fixed system would hamper mobility.

[0012] The air supply system may comprise two air pumps each configured to pump air in one direction, wherein the first air pump may be configured to move a capsule of the one or more capsules comprising a fastener from the feeding station to the end effector station and a second air pump may be configured to move the capsule back to the feeding station; or a single air pump configured to pump air in both directions to move the capsule from the feeding station to the end effector station and back again.

[0013] The capsule may comprise a first and second end, wherein one or both ends of the capsule comprises an external groove, wherein a polymer ring may be arranged in the groove(s). The first end may be the end in which the fastener is inserted and removed. Both rings reduce friction of the capsule against the wall of the hose, therefore accelerating delivery and retrieval of the capsule along the first tube. The bottom ring also makes the sealing of the tube more reliable which is beneficial when air is being used to move the capsule along the tube.

[0014] Each capsule may be arranged in a capsule holder in the feeding station. This prevents contamination of the capsules before they are transported along the first tube and provides a modular system.

[0015] An O-ring may be located within the capsule holder between the capsule holder and the second end of the capsule. This reduces the impact force between the capsule and the capsule holder when the capsule is returned to the capsule holder. This therefore minimizes risk of damage to the capsule so that it can be refilled with a fastener and used again.

[0016] The first and second tubes ends and capsule holder may be connected air tightly to enable the capsule to be moved through the hose by air pressure. The connection may also allow relative movement between the first and second tube and the capsule holder to be able to align the first and second tube with any capsule holder in the feeding station and to be able to fill the capsule holder with a new capsule or the capsule in the capsule holder with a new fastener. In order to achieve this the capsule holder may comprise a first end connectable to the first end of the first tube and a second end connectable to the first end of the second tube. The first and second tubes may be configured to be moved from a first open positon wherein the first ends of the first and second tubes are spaced from the first and second ends of the capsule holder to a second closed position wherein the first ends of the first and second tubes are in contact with the first and second ends of the capsule holder. This results in a single feeding station being able to transfer any capsule from or into any of the capsule holders and to fill the capsule holders with capsules and fasteners. This makes the system more flexible and results in a compact system that can operate with multiple capsules in quick succession.

[0017] The term 'connectable to the first end of the first / second tube' may mean that the capsule holder is connected via a separate component. For example, the first and second tubes may each have connecting portions which are configured to interface with the capsule holder. One of the functions of the connecting portions may be to create a tighter seal between the tubes and the capsule holder.

[0018] The first and second tubes and capsule holder may be moved relative to each other using actuators. Actuators may also be utilized to open and close the gap between the first and second tubes and the capsule holder. The actuators may be used to move moveable portions connected to the first and second tubes along a rail. Alternatively, the actuators may be pneumatic. Thus a compact system may be provided which can be automated.

[0019] The pressure in the first and second tubes may be monitored using one or more pressure sensors and the force applied by the actuators varied based on the pressure in the tubes. This ensures that enough force is applied by the actuators to keep the tubes in airtight contact with the capsule holder even when air is forced down the tubes.

[0020] The first end of the first and second tubes may be configured to be received by first and second ends of the capsule holder. In some examples, the first end of the first and second tubes may comprise funnel shaped portions for interfacing with first and second ends of the capsule holder. The funnel shaped portions may be part of the connecting portions. By having the first end of the first and second tubes being received by the first and second ends of the capsule holder, the system is tolerant to small assembly misalignments between the first and second tubes and the capsule holder. Furthermore, a tighter seal can be formed between the tubes and the capsule holder, which is beneficial when air is being used to move the capsule along the first tube.

[0021] The first tube may additionally comprise a pressure relief valve. The pressure relief valve may enable air to escape from the first tube if the pressure exceeds a particular level.

[0022] The capsule holder may comprise a seal, for instance an O-ring, at each end for interfacing with the first ends of the first and second tubes. In this way, air tightness is ensured.

[0023] The capsule holders may be arranged on the feeding station in a circular arrangement. The circular arrangement of the capsule holders provides a compact footprint and better scalability than other shaped stations.

[0024] The feeding station may comprise a rotary actuator, for example an electric rotary actuator. In this way, the actuator can be used to rotate the capsule holders so that once a capsule has been returned to the feeding station without the fastener, the capsule holders can be rotated so that another capsule holder with a capsule comprising a fastener inside can be lined up with the first and second tubes and a new fastener can be filled in the returned capsule.

[0025] Alternatively, the capsule holders may be arranged in the feeding station in a linear arrangement. This arrangement may be chosen based on the available space. The feeding station or the first end of the first and second tubes may be arranged on a rail along which the capsule holders or the first ends of the first and second tube are moveable in a linear direction. Movement of the linear feeding station arrangement or the first end of the first and second tubes along the rail may be automated.

[0026] The first tube may be a flexible hose. The hose may be flexible enough to not only comply with the movements of the robot arm, but also to apply negligible forces to the robot end effector, so that force and compliance control functions of the robot are not affected. On the other hand, the stiffness of the hose may be high enough to 1) force large enough radii of curvature of the hose, for the capsule to freely move through the hose and 2) make the amplitude of the vibrations of the hose negligible when the capsule is moving through the hose.

[0027] The first tube or the feeding station may comprise a sensor for detecting passing of a capsule. This may be beneficial for determining when a capsule has left the base station and also determining when the capsule has been returned to the base station. Once the capsule has returned into one of the capsule holders, the suction force can be switched off, the first end of the first and second tubes may be moved away from the capsule holder, after which the capsule holder arrangement may be rotated / moved to align the next capsule holder with the first and second tubes. This enables the process to be sped up.

[0028] When the sensor is located in the first tube, the first tube may be transparent and wherein the sensor may be a photoelectric sensor. In this way, the photoelectric sensor can detect when the capsule travels down the tube past the sensor. When the sensor is located in the feeding station, it may be a micro-switch or a capacitive proximity sensor.

[0029] The capsule holders may comprise a sensor for detecting retrieval of the capsule. In this way, it is possible to tell when capsules have been removed from the feeding station or returned to it. Thus, the feeding station can rotated / moved if required. The sensor may be a micro-switch or a capacitive proximity sensor.

[0030] The system may additionally comprise an end effector and wherein the end effector station comprises a capsule receiving portion, wherein the capsule receiving portion may be configured to receive the capsule from the first tube. The end effector may comprise a nose piece moveable between a first positon inside the capsule receiving portion and a second position outside the capsule receiving portion. The nose piece is configured to attach to the fastener to remove it from the capsule.

[0031] By being able to move the nose piece and capsule receiving portion between the first and second positions, it is possible for the capsule receiving portion to be moved out of the way so that it does not interfere with the nose piece installing the fastener in, for example, an aircraft.

[0032] The nose piece of the end effector may be moveable between the first and second positons using a robot arm. This can be controlled automatically so that when sensors in the system confirms a fastener has been attached and the capsule has been removed, the nose piece may be moved to the second position.

[0033] Additionally, the end effector station may be moveable with respect to the nose piece of the end effector using an end effector station actuator. Specifically, after the nose piece has been rotated into the first position, the end effector station may be rotated by the end effector station actuator to ensure that the nose piece is fully inside the end effector station. This ensures that the nose piece can be fully aligned with the capsule. The end effector station actuator may be a pneumatic actuator. This can be controlled automatically both when the nose piece is in the first position, so that alignment between nose piece and capsule receiving portion is ensured, and when the nose piece is in the second position, so that the end effector station is firmly held at distance from the nose piece and does not interfere with the fastening process. Additionally, compressed air may be removed from the pneumatic actuator during the movement of the nose piece between the first and second position; in this case the end effector station may be held in position by gravity while the nose piece moves inside and outside the capsule receiving portion of the end effector station.

[0034] The system may further comprise a capsule receiving portion actuation system wherein the capsule receiving portion actuation system may comprise a nose piece fork configured to abut the capsule. In this way, the nose piece fork can remove the fastener from the capsule before the capsule is returned to the feeding station.

[0035] For example, when the capsule enters the capsule receiving portion, the first end of the capsule may come into contact with the nose piece fork. As the capsule moves further into the capsule receiving portion, the fork may be forced along a rail in a first direction. The capsule receiving portion actuation system may comprise a nose piece fork actuator configured to move the nose piece fork in a second direction, opposite the first direction in order to remove the capsule from the fastener. The nose piece fork is moved in a second direction when the nose piece has attached to the fastener. The nose piece fork therefore enables the capsule to be removed from the capsule receiving portion towards the second hose. A suction is applied which draws the capsule back along the first tube to the capsule holder. The suction may be applied once the nose piece has removed the fastener from the capsule or whilst it is being removed.

[0036] In another example, a spring maybe used instead of the nose piece fork actuator. When the capsule is received in the capsule receiving portion and subsequently the fastener is inserted in the nose piece, the spring is loaded or extended. As soon as compressed air is discontinued, the force of the spring removes the capsule from the fastener so it can be returned along the first tube.

[0037] The capsule receiving portion actuation system may additionally comprise a sensor to measure the position of the fastener. For example, the sensor may comprise a linear potentiometer. The linear potentiometer may be fixed to the nose piece fork and may measure indirectly the position of the capsule and therefore, also indirectly, the position of the fastener. Since the nose piece fork abuts the capsule and the fastener is held in the capsule, the position of the capsule and of the fastener can be determined. Therefore, it is possible to establish whether and when the pin of the fastener is inside the nose piece for a sufficient length. If a sufficient length of the fastener is not inside the nose piece, the capsule may be forced further into the capsule (for example by continuing to input air through the first tube) until the sensor detects that a sufficient length of the fastener is inside the nose piece. If the capsule was removed before the fastener was sufficiently received by the nose piece, this could lead to the nose piece dropping the fastener.

[0038] Viewed from a second aspect, there is provided a method for installing fasteners in an aircraft. The method comprises positioning one or more capsules in capsule holders of a feeding station, wherein each capsule comprises a fastener wherein at least part of each fastener is coated with sealant, aligning a capsule of the one or more capsules with a first tube located above the capsule holder; aligning the capsule holder with a second tube located below the capsule holder; closing a gap between the capsule holder and the first and second tube; applying compressed air to the capsule holder through the second tube causing the capsule comprising the fastener to travel along the second tube towards an end effector station; removing the fastener from the capsule in the end effector station and applying air extraction to the second tube, wherein the air extraction draws the capsule without the fastener along the first tube and into the capsule holder.

[0039] The capsule holders each comprising a capsule may be provided already positioned in the feeding station. At this point, the fasteners with sealant may be added to each of the capsules.

[0040] Once the capsule has been returned to the capsule holder, the method may comprise moving the feeding station (either by rotation or translation) so that the first and second tubes are aligned with a different capsule comprising a fastener. This method may be repeated until all capsules comprising fasteners in the feeding station have been transported to the end effector station. Alternatively, the capsules may be repeatedly filled with fasteners. Each capsule holder may have a different internal geometry to accommodate: fasteners of a different type, fasteners with another diameter or fasteners in another grip length range. The fasteners that remain in the nose piece after the capsule is returned to the capsule holder may be installed in an aircraft structure.

[0041] Other aspects will also become apparent upon review of the present disclosure, in particular upon review of the Brief Description of the Drawings, Detailed Description and Claims sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Examples of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0043] Figure 1 shows a system for installing fasteners in an aircraft;

[0044] Figures 2A shows a fastener, figures 2B to 2F show a capsule containing a fastener and figures 2G and 2H show a holding ring for locating inside the capsule.

[0045] Figures 3Aand 3B showa zoomed in portion of a feeding station of the system according to a first teaching and figure 3C shows a zoomed in portion of a feeding station of the system according to a second teaching;

[0046] Figure 4 shows an air supply system according to the invention;

[0047] Figures 5A and 5B show zoomed in portions of the capsule and a first and second tube;

[0048] Figures 6A to 6C show an end effector, end effector station and capsule receiving portion and figures 6D and 6E show end effector of the system in first and second rotational positions;

[0049] Figures 7A and 7B show a capsule receiving portion of the system with a nose piece inside receiving the capsule;

[0050] Figures 8A and 8B show a capsule receiving portion actuation system; and

[0051] Figures 9A and 9B show the capsule receiving portion actuation system in a resting and activated position and figure 9C shows an alternative arrangement of the capsule receiving portion actuation system.

[0052] While the disclosure is susceptible to various modifications and alternative forms, specific example approaches are shown by way of example in the drawings and are herein described in detail. It should be understood however that the drawings and detailed description attached hereto are not intended to limit the disclosure to the particular form disclosed but rather the disclosure is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the claimed invention.

[0053] As used in this specification, the words "comprises", "comprising", and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean "including, but not limited to".

[0054] It will be recognised that the features of the above-described examples of the disclosure can conveniently and interchangeably be used in any suitable combination. It will also be recognised that the invention covers not only individual embodiments but also combinations of the embodiments that have been discussed herein. DETAILED DESCRIPTION

[0055] The present teaching relates particularly, but not exclusively, to a system for installing fasteners in an aircraft. It will be recognised from the disclosure herein that the system could be used for installing fasteners in other applications, for example any assembly requiring fasteners.

[0056] Figure 1 shows a system 1 for installing fasteners in an aircraft. The system 1 comprises a feeding station 2. Each feeding station 2 comprises a plurality of capsules holders 4. The capsule holders 4 are configured to hold capsules (not shown) which are themselves configured to hold fasteners. At least part of each fastener may be coated with sealant. The system additionally comprises an end effector 18. The end effector 18 comprises a nose piece 17 and is rotatably attached to an end effector station 3 comprising a capsule receiving portion 6.

[0057] A first tube 5 links the feeding station 2 at a first end with the capsule receiving portion 6 at a second end. The end effector 18 is rotatable between a first position where the nose piece 17 is located inside the capsule receiving portion 6 and a second position (shown in figure 1) where the nose piece is located outside the capsule receiving portion 6. This will be discussed further later (see for example figure 6A).

[0058] Part of the first tube 5 is held in place by a balancer pole 7 with a hook 7a. Alternatively the first tube 5 may be attached to the robot itself. Capsules (not shown in this figure) are configured to travel one at a time from a capsule holder 4, along the first tube 5 to the capsule receiving portion 6. The fastener inside the capsule is then transferred to the nose piece 17 when the end effector 18 is in the first position. The end effector 18 is then rotated to the second position (shown in figure 1) with the fastener attached to the nose piece. The fastener can then be installed in the aircraft.

[0059] Figures 2A to 2F show the fastener 8 and capsule 9. Figure 2A shows the fastener 8 outside the capsule 9. The fastener 8 comprises a threaded fastener pin 8a and an anvil 8c. Figure 2B shows a perspective view of the capsule 9 with the fastener 8 installed inside. Figure 2C shows a cross-sectional view of the capsule 9 with the fastener 8 installed inside. The capsule 9 comprises a compliant mechanism 9b acting as a first holding mechanism and configured to hold a tip 8b of the fastener 8. Specifically, the compliant mechanism 9a may be formed of a flexible material so that the fastener may be forced into or extracted from the mechanism if enough force is applied through elastic body deformation of the mechanism. Thus, the fastener 8 is releasably attached to the capsule 9.

[0060] As can be seen from figure 2C, a first end (shown at the top of figures 2B to 2D) of the capsule 9 is open in order to receive / release the fastener 8. A space exists between the end of the fastener pin 8a and the first end of the capsule. Thus, the capsule 9 can be used to carry a longer fastener than that shown in this figure. Thus the capsules can be used for a number of different fastener types and lengths. Furthermore, the space is used to align the capsule with a nose piece of an end effector (discussed later) before the fastener pin is inserted in the nose piece. That makes the system less sensitive to misalignments between the nose piece with the end effector station. The capsules 9 are usually formed by 3D printing or injection moulding. The second end (shown at the bottom of figures 2B to 2D) of the capsule 9 is closed. The system is configured to function with a particular sized capsule. In this way, the capsules are compatible with the first tube and the stations.

[0061] Figures 2D and 2E show an alternative design for the capsule 9. In this, the capsule additionally comprises a holding ring 26. This is shown enlarged in figures 2G and 2H. Specifically, figure 2G shows an upper perspective view of the holding ring 26 and figure 2H shows a lower perspective view of the holding ring 26. The holding ring 26 is located inside the capsule and functions as a second holding mechanism which is configured to hold the fastener 8 in place in the capsule 9. The holding ring 26 is inserted into the capsule 9 after insertion of the fastener. The friction between the fastener 8 and the holding ring 26 is lower than the friction between the holding ring 26 and the inside of the capsule 9. Thus, when in the end effector station, the capsule 9 is removed from the fastener 8, the holding ring 26 stays inside the capsule 9 and is returned to the feeding station with the capsule 9. Before the capsule is loaded with the new fastener at the base station, the holding ring 26 is removed from the capsule.

[0062] As can be seen from figure 2G, the holding ring 26 may comprise an integrated cover 26a. This prevents leakage of the sealant in the hose or in other elements of the system, during transport of the fastener 8.

[0063] Figure 2F shows an alternative design for the capsule 9 with the same size as the capsule shown in figures 2B to 2E. The capsule 9 comprises a groove (not shown) at each of the first and second ends, in which is placed an O-ring 9a. The O-rings 9a may be formed of a polymer such as Teflon or plastic.

[0064] Figure 3A to 3B show the feeding station 2 in more detail. In this example, the feeding station 2 comprises three capsule holders 4 arranged on a circular capsule holder plate 10 in a circular arrangement. As well as the first tube 5 which is located above the circular capsule holder plate 10, a second tube 12 is located below the circular capsule holder plate 10. The first and second tubes 5, 12 are moveable between a first open position (shown in figure 3A) where the first end of each of the hoses is spaced from a top / bottom of the capsule holder 4 to a second closed position (shown in figure 3B) where the second end of each of the hoses abuts with a top / bottom of the capsule holder 4. The first and second tubes are flexible hoses.

[0065] The first and second tubes 5,12 are moved between the first and second positions using actuators 13 attached to a rail 27. In other examples, pneumatic actuators 13 may be used to move the tubes between the first and second positions. This is shown in figure 3C where pneumatic actuators 13 rotate the first and second tubes 5, 12 between the first and second positions. For example, a pressure in the first and second tubes 5,12 may be monitored using one or more pressure sensors (not shown) and the force applied by the actuators varied based on the pressure in the tubes. Specifically, the force applied by the actuators may be controlled to ensure that the first and second tubes 5,12 are held in the closed position when desired even when the pressure in the first and second tubes 5, 12 increases.

[0066] The second tube 12 is connected to an air supply and extraction system (not shown). In one example, the air supply system may comprise a compressed air and suction system. When it is desired to move a capsule 9 containing a fastener 8 from the feeding station 2 to the end effector station 3 (shown in figure 6), the first and second tubes 5, 12 are moved into the closed position (see figure 3B) and a compressed air is applied through the second tube 12. This causes the capsule 9 to leave the capsule holder 4 and travel along the first tube 5 to the end effector station 3. At the end effector station 3, the fastener 8 is removed from the capsule (as will be discussed further later). A suction or vacuum is applied from the air supply and extraction system which causes the capsule 9 to be drawn back along the first tube 5 into the feeding station 2.

[0067] Turning to figure 4, in another example, the air supply and extraction system may comprise an air pump based air supply system 14. The air pump based air supply and extraction system 14 comprises two air pumps: a first air pump 14a configured to blow air into the second tube 12 and move a capsule 9 of the one or more capsules from the feeding station 2 to the end effector station 3 and a second air pump 14b configured to suck air out of the hose to pull the capsule 9 back to the feeding station 2, while the fastener remains in the nose piece. Only one air pump must be switched on at a certain time, depending on the direction the capsule has to move.

[0068] The circular capsule holder plate 10 is attached to a rotary actuator 11. The rotary actuator 11 is able to rotate the circular capsule holder plate 10 so that the first and second tubes 5, 12 are aligned with a different capsule holder 4. The circular capsule holder plate 10 is rotated when the first and second tubes 5, 12 are in the open position (figure 3A).

[0069] Instead of a circular capsule holder plate 10 with the capsule holders 4 arranged in a circular arrangement, the capsule holders 4 may be arranged in the feeding station 2 in a linear arrangement. For example, the capsule holders 4 may be arranged in a line on a plate which is arranged on a rail along which it is moveable in a linear direction. In this way, the plate linearly moves positions in order to align any capsule holder 4 with the first and second tubes 5, 12.

[0070] Figures 5A and 5B show zoomed in portions of the first and second tubes 5, 12 in the closed position (figure 5A) abutting with a capsule holder 4 and the open position (figure 5B) spaced from the capsule holder 4. An O-ring 25 is located within the capsule holder at the second end of the capsule 9 when it is located inside the capsule holder.

[0071] The first ends of the first and second tubes 5, 12 comprise connecting portions 5b, 12b for interfacing with first and second ends of the capsule holder. The capsule holder 4 comprises an O-ring 15 at each end for interfacing with the first ends of the first and second tubes. This to ensure a tight fit when the first and second tubes 5, 12 are in the closed position.

[0072] In some examples, the first tube 5 comprises a sensor (not shown) for detecting passing of a capsule. For example, the first tube 5 may be transparent and the sensor may be a photoelectric sensor. In this way, the sensor can sense when the solid capsule 9 passes along the transparent tube 5 due to the change in light. In other examples, a sensor is present in the capsule holder 4 to detect presence of the capsule 9. For example a micro-switch or a capacitive sensor may be used.

[0073] Figure 6A shows the robot end effector, figure 6B shows the end effector station 3 comprising the capsule receiving portion 6, and figure 6C shows the capsule receiving portion 6.

[0074] Figures 6D and 6E show the end effector station 3 assembled with the capsule receiving portion 6. Figure 6D shows the end effector 18 in the second rotational position where the nose piece 17 is located outside the capsule receiving portion 6. Figure 6E shows the end effector 18 in the first rotational position where the nose piece 17 is located inside the capsule receiving portion 6. The end effector 18 is rotated between the first rotational position (shown in figure 6E) and the second rotational position (shown in figure 1 and 6D) by the robot.

[0075] Once the end effector 18 has been rotated into the first rotational position as shown in figure 6E, an actuator 19 is activated or extended. This activation of the actuator 19 causes the end effector station 3 to be rotated so that the nose piece 17 is aligned with the capsule receiving portion 6 and the nose piece is pressed against the end effector station 3. This ensures alignment between the capsule 9 and the nose piece 17. When the actuator 19 is retracted, the end effector station 3 is rotated with respect to the nose piece 17. Next, the end effector 18 is rotated by the robot to the second position shown in figure 6D such that the nose piece 17 is located fully outside of the capsule receiving portion 6 . This prevents interference of the capsule receiving portion 6 in the fastening process. The capsule receiving portion 6 comprises a funnel 6a to receive the capsule and align it with the nose piece. The end effector station 3 further comprises brackets 28 with a capsule arrival detection subsystem (discussed further later).

[0076] Although figures 6D and 6E show a single end effector 18 coupled with the end effector station 3, in some examples, multiple end effectors may be used. Each of these may be connected separately by a separate tube to the feeding station or by the same tube. The system may further include a tool changer to switch between end effectors. This enables different capsules carrying different size fasteners to be transported to previously chosen end effectors.

[0077] Figures 7A and 7B show the nose piece 17 of the end effector 18 in the first rotational position, i.e. with the nose piece 17 inside the capsule receiving portion 6. The end effector station 3 has also been rotated with respect to the nose piece by the actuator 19 as discussed above to ensure the nose piece 17 aligns with the capsule 9. As can be seen from these cross-sectional views, when the capsule 9 is inside the capsule receiving portion 6, the nose piece 17 is inserted into one end of the capsule 9. A centrally located hole in the nose piece 17 connects with the fastener 8 and holds it firm whilst the capsule is removed. In this way, the capsule 9 is detached from the fastener 8. The nose piece 17 may comprise grippers to hold the fastener 8 (not shown).

[0078] Figure 7A shows the capsule 9 holding a longer fastener 8 than is shown in figure 7B. The capsule 9 itself is the same size in both figures. When a shorter fastener 8 is being transported by the system (see figure 7B), the nose piece 17 travels further into the capsule 9 to reach the fastener until the ends of the capsule abut a stepped portion on the outside of the nose piece 17. This stepped portion and the abutment between the nose piece 17 and the capsule 9 is shown by the circular annotations on figure 7B. Therefore, any given capsule can transport fasteners of a range of lengths. The capsule may be made by 3D printing or injection moulding.

[0079] Figures 8A and 8B show zoomed views of the capsule receiving portion 6 along with a capsule receiving portion actuation system. The capsule receiving portion actuation system comprises a nose piece fork 20, a nose piece fork actuator 21, a linear potentiometer 22, a rail 23 along which the nose piece fork 20 is configured to slide and actuator brackets 24 which connect the linear potentiometer 22 with the nose piece fork actuator 21. When the capsule 9 enters the capsule receiving portion 6, the top of the capsule 9 comes into contact with the nose piece fork 20 which causes the fork to slide upwards. The capsule 9 stops moving when the fastener's anvil 8c stops against the nose piece 17.

[0080] The linear potentiometer 22 fixed to the nose piece fork 20 measures indirectly the position of the capsule 9 and therefore, also indirectly, the position of the fastener 8. Since the nose piece fork 22 rests against the capsule 9 and the fastener 8 is held in the capsule 9, the position of the capsule 9 and of the fastener 8 can be determined. Therefore, it is possible to establish whether and when the pin 8a of the fastener 8 is inside the nose piece 17 for a sufficient length. Additionally, malfunctions of the system can be detected, e.g.: the nose piece fork 20 is too far from the end effector 3: the pin 8a of the fastener 8 is not sufficiently inside the nose piece 17, or that the pin 8a has not entered the nose piece 17. the nose piece fork 20 is too close to the end effector 3: it might be that the fastener is missing from the capsule, or that the end effector 3 is not at all aligned with the nose piece 17.

[0081] Figures 8A and 8B show how the positioning of the parts of the actuation system vary based on the size of the fastener 8 inside the capsule 9. When a shorter fastener 8 is inside the capsule 9 (as shown in figure 8A), the capsule 9 moves further into the capsule receiving portion 6 before the fastener's anvil 8c abuts the nose piece 17. Figure 8B shows the positioning of the capsule when a longer fastener 8 is inside the capsule 9.

[0082] Compressed air is constantly supplied in the nose piece fork actuator 21 connected to the nose piece fork 20. This ensures that the nose piece fork 20 is in front of the nose piece before the capsule is received and so that it remains in contact with the front of the capsule when the capsule is received. Low pressure levels are used (typically 1 or 2 bars) so that the capsule doesn't meet too much resistance when being delivered.

[0083] As shown in these figures, there may be a tube adaptor 29 connecting the first tube 5 to the capsule receiving portion 6. Once the capsule 9 is inside the capsule receiving portion 6 as shown in figures 8Aand 8B, the base of the capsule 9 fills the capsule receiving portion 6 and therefore seals off the first tube 5. As a consequence, pressures builds up in the hose. This provides additional force to push the capsule forward as the resistance to insert the pin of the fastener 8 inside the nose piece 17 is overcome. Typically the pressure in the first tube 5 becomes 1 to 2 bar. In other examples, the pressure may reach 0.5 to 1 bar.

[0084] Once the fastener pin 8a is located inside the nose piece 17, it is pulled out of the compliant mechanism 9b of the capsule 9. For certain pull-type fasteners, the design of the nose piece 17 is such that, once the fastener pin 8a is inside the nose piece 17, the pulling force required to retrieve the fastener is much higher than the force required to slide the capsule 9 out of the fastener 8. Alternatively, for other fastener types, a device (e.g. a small gripper, scissors..) or system (e.g. a vacuum system) is added to the nose piece 17 in order to retain the fastener while the capsule is being retrieved.

[0085] To remove the capsule 9 from the capsule receiving portion 6, compressed air with higher pressure (for example approximately 6 bar) is provided to the nose piece fork actuator 21, such that the nose piece fork 20 pushes with force against the capsule 9. As the capsule 9 is pushed towards the first tube 5, the fastener 8 remains in the nose piece. At the same time, an air suction is applied in the first tube 5 using the air supply system, so that the capsule 9 is retrieved. In some examples, only air suction is applied to retrieve the capsule, although that may be less reliable.

[0086] Figures 9A and 9B show movement of the different parts of the capsule receiving portion actuation system as the capsule 9 enters the actuation system. As can be seen in figure 9A, before the capsule 9 enters the actuation system, the nose piece fork 20 is located at a first position with respect to the nose piece 17. When the capsule 9 comprising the fastener 8 enters the capsule receiving portion 6, the nose piece fork 20 moves up the nose piece 17 until the fastener's anvil 8c abuts the nose piece 17.

[0087] Figure 9C shows an alternative arrangement of the capsule receiving portion actuation system. In this system, instead of having an actuator connected to the nose piece fork 20, a spring 30 is used. The spring 30 both ensures that the fork 20 remains in contact with the first end of the capsule 9 (to measure its position) and applies some force to it in order to facilitate its retrieval once the pressure in the first tube reduces.

[0088] A method for installing fasteners 8 in an aircraft will now be described. Fasteners 8 are coated with sealant. The fasteners 9 are each placed in the capsules 9. The capsules 9 are positioned in in the capsule holder 4 of the feeding station 2. One of the capsules 9 is aligned with the first tube 5 located above the capsule holder 4 and the second tube 12 located below the capsule holder 4. The fasteners 8 may be automatically placed in the capsules for example using a Cartesian robot.

[0089] Compressed air is driven through the second tube 12 causing the capsule 9 comprising the fastener 8 to travel along the second tube 12 towards the end effector station 3. The capsule 9 enters the capsule receiving portion 6. The fastener 8 is removed from the capsule 9 as discussed above. The fastener may then be installed in an aircraft or other application. Meanwhile, the capsule 9 is then removed from the capsule receiving portion 6 by applying air extraction to the second tube 12, wherein the air extraction draws the capsule without the fastener along the first tube 5 and into the capsule holder 4. A sensor (e.g. a capacitive proximity sensor or a micro-switch) may be located in the capsule holder 4 and may confirm the capsule has returned to the capsule holder 4 in the feeding station. The air extraction in the first tube 5 is then stopped.

[0090] The capsule holder holding plate 4 is then rotated (if a circular arrangement of capsule holders is used) or translated (if a linear arrangement of capsule holder is used) and a new capsule is aligned with the first tube 5 located above the capsule holder 4 and the second tube 12 located below the capsule holder 4. The method is repeated for each capsule 9 in the capsule holder 4. Additionally, the capsule holders are reloaded with further capsules 9. This may be done by a further end effector. Each capsule holder 4 may have a different capsule for different fastener diameters or a different range of grip length. Therefore, it is necessary to ensure the capsules are loaded into the appropriate capsule in order to be sent. This information may be provided to the end effector for loading the capsule holders 4.

[0091] The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and / or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and / or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the spirit and scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc., other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.

Claims

1. A system for installing fasteners in an aircraft structure, the system comprising:a feeding station comprising one or more fasteners, each fastener arranged in a capsule, wherein at least part of each fastener is coated with sealant;an end effector station;a first tube configured to connect to the feeding station at a first end and to the end effector station at a second end and configured to transport capsules comprising the one or more fasteners coated with sealant from the feeding station to the end effector station; anda second tube configured to connect to the feeding station at a first end and to an air supply and extraction system at a second end.

2. The system of claim 1, wherein each capsule comprises a first holding mechanism for releasably attaching to a tip of the fastener.

3. The system of claim 2, wherein each capsule additionally comprises a second holding mechanism configured to hold the fastener within the capsule as the capsule is transported along the first tube.

4. The system of any of claims 1 to 3, wherein the air supply and extraction system comprises a compressed air and suction system configured to move a capsule of the one or more capsules comprising a fastener from the feeding station to the end effector station and configured to move the capsule back to the feeding station.

5. The system of any of claims 1 to 3, wherein the air supply system comprises:two air pumps each configured to pump air in one direction, wherein the first air pump is configured to move a capsule of the one or more capsules comprising a fastener from the feeding station to the end effector station and a second air pump configured to move the capsule back to the feeding station; ora single air pump configured to pump air in both directions to move the capsule from the feeding station to the end effector docking station and back again.

6. The system of any preceding claim, wherein the capsule comprises a first and second end, wherein one or both ends of the capsule comprises an external groove, wherein a polymer ring is arranged in the groove(s).

7. The system of any preceding claim, wherein each capsule is arranged in a capsule holder in the feeding station.

8. The system of claim 7, wherein an O-ring is located within the capsule holder between the capsule holder and the capsule.

9. The system of claim 7 or 8, wherein the capsule holder comprises a first end connectable to the first end of the first tube and a second end connectableto the first end of the second tube, wherein the first and second tubes are configured to be moved from a first open positon wherein the first ends of the first and second tubes are spaced from the first and second ends of the capsule holder to a second closed position wherein the first ends of the first and second tubes are in contact with the first and second ends of the capsule holder.

10. The system of claim 9, wherein the first and second tubes are moved between the first and second positions using actuators.

11. The system of claim 10, wherein a pressure in the first and second tubes is monitored using one or more pressure sensors and the force applied by the actuators varied based on the pressure in the tubes.

12. The system of any preceding claim, wherein the first tube additionally comprises a pressure relief valve.

13. The system of any of claims 7 to 11, wherein the first end of the first and second tubes are configured to be received by first and second ends of the capsule holder.

14. The system of any of claims 7 to 13, wherein the capsule holder comprises a seal at each end for interfacing with the first ends of the first and second tubes.

15. The system of any of claims 7 to 14, wherein the capsule holders are arranged on the feeding station in a circular arrangement.

16. The system of claim 15, wherein the feeding station comprises a rotary actuator.

17. The system of any of claims 7 to 14, wherein the capsule holders are arranged in the feedingstation in a linear arrangement.

18. The system of claim 17, wherein the feeding station or the first end of the first and secondtubes is / are arranged on a rail along which the capsule holders or the first ends of the first and second tube are moveable in a linear direction19. The system of any preceding claim, wherein the first tube is a flexible hose.

20. The system of any preceding claim, wherein the first tube or the feeding station comprises asensor for detecting passing of a capsule.

21. The system of claim 20, wherein the first tube is transparent and wherein the sensor is a photoelectric sensor.

22. The system of any of claims 7 to 18, wherein the capsule holders comprise a sensor for detecting retrieval of the capsule.

23. The system of claim 22, wherein the sensor is a micro-switch or a capacitive proximity sensor.

24. The system of any preceding claim, additionally comprising an end effector and wherein theend effector station comprises a capsule receiving portion, wherein the capsule receiving portion is configured to receive the capsule from the first tube, wherein the end effector comprises a nose piece moveable between a first positon inside the capsule receiving portion and a second position outside the capsule receiving portion.

25. The system of claim 24, wherein the end effector station is moveable with respect to the nose piece using an end effector station actuator.

26. The system of any preceding claim, additionally comprising a capsule receiving portion actuation system, wherein the capsule receiving portion actuation system comprises a nose piece fork configured to abut the capsule.

27. The system of claim 26, wherein when the capsule enters the capsule receiving portion, the abutment of the capsule with the fork causes movement of the nose piece fork in a first direction and wherein the capsule receiving portion actuation system comprises a nose piece fork actuator configured to move the nose piece fork in a second direction, opposite the first direction in order to remove the capsule from the fastener.

28. The system of claim 26, wherein when the capsule enters the capsule receiving portion, the abutment of the capsule with the fork causes movement of the nose piece fork in a first direction and wherein the capsule receiving portion actuation system comprises a spring configured to move the nose piece fork in a second direction, opposite the first direction in order to remove the capsule from the fastener.

29. The system of any of claims 26 to 28, wherein the capsule receiving portion actuation system additionally comprises a sensor to measure the position of the fastener.

30. A method for installing fasteners in an aircraft, the method comprising:positioning one or more capsules in capsule holders of a feeding station, wherein each capsule comprises a fastener wherein at least part of each fastener is coated with sealant;aligning a capsule holder of the one or more capsule holders with a first tube located above the capsule holder and a second tube located below the capsule holder;closing a gap between the capsule holder and the first and second tube;applying compressed air to the capsule holder through the second tube causing the capsule comprising the fastener to travel along the second tube towards an end effector station;applying air extraction to the second tube, wherein the air extraction draws the capsule without the fastener along the first tube and into the capsule holder.s

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