This invention relates to an ultrasound probe carrier for carrying one or more ultrasonic probes through a composite structure, such as a carbon fibre aircraft wing or aileron, to test an internal wall, such as a vertical bulkhead wall, within the structure for potential flaws.

Composite structures are frequently used in aerospace applications, such as wings and ailerons, in view of the engineering qualities, design flexibility and low weight of such structures. However, before such composite structures can be used in critical applications, such as aircraft wings, it is necessary to inspect the structures to identify any flaws, such as cracks, voids or porosity, which could adversely affect the performance of the composite structure.

Non-destructive testing of composite structures can be carried out using ultrasonic probes, which can identify flaws within a composite structure. External surfaces of components can be easily tested using ultrasonic probes. However, greater difficulty arises when it is necessary to test the integrity of internal structures, such as ribs and bulkhead walls, within a complex composite component, such as an aircraft wing or aileron.

Figure 1 shows a section of an aileron of an aircraft wing formed from carbon fibre. The aileron 2 comprises an outer skin 4 defining a hollow body. A plurality of parallel vertical bulkhead walls 6,7,8 are provided extending along the length of the aileron 2 to reinforce the structure. It is desirable to test the integrity of each of said vertical bulkhead walls 6,7,8 before the component is put into service, in particular in relation to the join between each vertical bulkhead wall 6,7,8 and the outer skin 4 of the component. Such testing may be performed by traversing an ultrasonic probe along a face of each bulkhead wall 6,7,8, adjacent its join with the outer skin 4 of the component. However, it can be very difficult to guide an ultrasonic probe over the surface of each bulkhead wall along the full length of the wall, particularly for large components.

According to the present invention there is provided an ultrasonic probe carrier comprising a first part having a contact face adapted to be located against a face of an internal wall of composite structure; a second part adapted to be located against a second face of said internal wall on an opposite side of said internal wall to said first part; said first part having at least one ultrasonic probe provided on said contact face thereof to be placed in contact with said internal wall; said first and second parts being provided with one or more magnets or ferromagnetic elements whereby one or more magnets provided on one of the first and second parts are arranged to attract one or more magnets or ferromagnetic elements provided on the other of the first and second parts to define a magnetic coupling between the first and second parts to retain said at least one ultrasonic probe in contact with said first face of said internal wall; at least one of said first and second parts being provided with a tether whereby the probe carrier can be pulled through a hollow section of a composite structure with said first and second parts in contact with opposite sides of an internal wall of said composite structure.

Said first part may comprise a carrier part having at least one ultrasonic probe mounted thereon, said second part comprising a follower part.

In one embodiment said first part comprises a first section, said first section having a first ultrasonic probe mounted thereon, and a second section pivotally connected to said first section about a pivot axis extending perpendicular to said contact face of said first part, wherein said second section can pivot with respect to said first section between a first position, wherein the first and second sections are substantially coplanar with one another, and a second position, wherein said second section extends at an acute angle to said first section, biasing means being provided for biasing said second section towards its second portion, whereby, in use, said first section abuts a first inner face of said composite structure adjacent a first end of said internal wall and said second section abuts a second inner face of said composite structure adjacent a second end of said internal wall opposite to and facing said first inner face.

Preferably said second section of said first part has a second ultrasonic probe mounted thereon. Said biasing means may comprise a spring or spring loaded plunger. Alternatively said biasing means may comprise a pair of magnets of opposite polarity to provide a magnetic biasing force urging said section to its second position.

Preferably said first section comprising a leading end of said first part, said tether being connected to said first section, said second section of the first part comprising a trailing end of said first part.

Preferably said first part is provided with a further elongate member or leg extending from a side of said first portion of the first part perpendicular to said contact face, said further elongate member being moveable under the action of a biasing means from a retracted position to an extended position to engage, in use, said second inner face of the composite structure. In one embodiment said further elongate member comprises a finger pivotally mounted on the first part to pivot between said retracted and extended positions about an axis perpendicular to said contact face.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:- Figure 2 is a perspective view of an ultrasonic probe carrier in accordance with an embodiment of the present invention being inserted into the aileron of Figure 1 ;

Figure 3 is a plan view of the ultrasonic probe carrier of Figure 2;

Figure 4 is a perspective view of a first part of the ultrasonic probe carrier of Figure 2; Figure 5 is a further perspective view of the first part of the ultrasonic probe carrier of Figure 2; Figure 6 is a further perspective view of the first part of the ultrasonic probe carrier of Figure 2; Figure 7 is a side view of a portion of the first part of the ultrasonic probe carrier of Figure 2; Figure 8 is a further perspective view of the first part of the ultrasonic probe carrier of Figure 2; and

Figure 9 is a perspective view of a second part of the ultrasonic probe carrier of Figure 2.

As shown in Figures 2 to 9, an ultrasonic probe carrier in accordance with an embodiment of the present invention comprises a carrier part 10 having a substantially planar contact face 12 (see Figure 5) in which a pair of ultrasonic probes 30,40 are mounted, said contact face 12 being adapted to be located against a first face of a vertical bulkhead wall 6,7,8 of an aileron on a first side of said bulkhead wall so that the ultrasonic probes are placed in contact with said face of the bulkhead wall, and a follower part 20 adapted to be located against a second face of said bulkhead wall on an opposite side of said bulkhead wall to said first part 10. Magnets (14, Figure 5) are mounted in each of the carrier and follower parts 10,20 wherein the magnets of the carrier part 10 are arranged to attract the magnets of the follower part 20 to define a magnetic coupling between the parts 10,20 to retain said carrier 10 and follower 20 on either side of bulkhead wall with the ultrasonic probes 30,40 in contact with said first face of the bulkhead wall. The magnets are preferably permanent magnets, such as a neodymium magnets, inserted into recesses in the body of the carrier and follower parts 10,20.

A tether 16 is connected to a leading end of the carrier part 10 whereby the probe carrier can be pulled through a hollow section A of the aileron with carrier part 10 and follower part 20 in respective contact with opposite sides of a bulkhead wall 6 of the aileron 2.

The carrier part 10 comprises an elongate leading section 50, said leading section 50 having a first ultrasonic probe 30 mounted thereon, said trailing section 55 being pivotally connected to said leading section 50 about a pivot axis 52 extending perpendicular to said contact face 12 of the carrier part 10, wherein said trailing section 55 can pivot with respect to said leading section 50 between a first position, wherein the leading and trailing sections 50,55 are substantially coplanar with one another, and a second position, wherein the trailing section 55 extends at an acute angle to the leading section 50. A biasing mean, such as a spring, is provided for biasing the trailing section 55 towards its second portion, whereby, in use, a lower side of the leading section 50 abuts a lower wall of the aileron section A into which the carrier part 10 is inserted, adjacent a lower end of the bulkhead wall 6 to be tested and a trailing upper end of the trailing section 55 is biased against the upper wall of the aileron section A adjacent an upper end of the bulkhead wall 6 so that the first ultrasonic probe 30 is located against the bulkhead wall 6 adjacent the lower wall of the aileron section and the second ultrasonic probe 40 is located against the bulkhead wall 6 adjacent the upper wall of the aileron section.

The leading section 50 of the carrier part 10 is provided with a laterally projecting finger 60 extending from a side of said leading section 50 perpendicular to said contact face 12. The finger 60 is pivotally moveable about a pivot axis 62 perpendicular to said contact face 12 between a retracted position, shown in Figure 8, and an extended position, shown in Figure 7, the finger 60 being biased towards its extended position by means of a spring loaded plunger 64such that the finger 60 engages, in use, an upper wall of the aileron section A, adjacent said bulkhead wall 6, when the carrier is inserted into the aileron section A. The finger 60 maintains a forward end of the leading section 50 of the carrier part 10 in contact with the lower wall of the aileron section A. The carrier and follower parts 10,20 of the carrier may be made from nylon, although any plastic or non ferrous metal could be utilised. As described above, the carrier part 10 is made in two sections, a leading section 50 and a trailing section 55 hinged together in the vertical plane for pivotal movement about an axis 52 perpendicular to said vertical plane, in each of the sections 50,55 a recess is machined to house the respective probe 30,40.

The contact face 12 of the carrier part 10 and the corresponding contact face of the follower part 20 may be provided with a central recess 18 between upper and lower guide tracks or ridges 22,24 (see Figure 5) to reduce the surface area of the contact faces of the carrier part 10 and follower part 20 in contact with the respective sides of the bulkhead wall 6 to reduce the friction between said contact faces and the bulkhead wall 6.

The leading section 50 of the carrier part 10 is designed to run along the bottom of the aileron section A adjacent the bulkhead wall 6 being scanned with its contact face 12 against the bulkhead wall 6. The carrier is held in place, with the carrier part 10 and follower parts on opposite sides of the bulkhead wall 6, by means of the magnets 14. The magnetic attraction of the respective magnets 14 holds both the carrier part 10 and the follower part 20 in contact with the bulkhead wall 6.

The carrier is then pulled through the component via the tether 16, for example using an electric winch, the follower part 20, held against the bulkhead wall 6 by the magnets 14, follows the carrier part 10, holding it in place all the way through the aileron section A. If the internal wall being tested is not of a uniform height, as is the case in almost all occasions, especially in the aircraft industry, the hinged trailing section 55 of the carrier is adapted to compensate for varying heights of the bulkhead wall. The trailing section 55, carrying the second probe, is biased (for example spring loaded) to always rise up to the roof or upper wall of the component, keeping the probe 40 provided on said trailer section 55, always in the highest position in the wall 6.

The biasing action between the leading and trailing parts of the carrier part 10 may be achieved by coil springs. Alternatively, the biasing action may be provided by the repelling actions of similar polarity abutting faces of permanent magnets to achieve the same effect as the coil springs. The use of magnets may be a particularly preferred option when operating underwater.

In a modified embodiment the follower part may also be formed from leading and trailing sections pivotally connected to one another in a similar manner to the carrier part, such that the trailing section of the follower part can pivot with respect to the leading section thereof to remain opposite the trailing section of the carrier part, the trailing sections of the carrier part and follower part both being provided with cooperating magnets for holding the trailing section of the carrier part in contact with the bulkhead wall.

The invention is not limited to the embodiment(s) described herein but can be

amended or modified without departing from the scope of the present invention.