Probe

The invention relates to a wear base for attachment to an ultrasonic test probe provided for the ultrasonic inspection of bar stock, the ultrasonic test probe comprising a fluid chamber which, in the operational state of the ultrasonic test probe, is filled with a coupling fluid or through which this coupling fluid flows, wherein the wear base is provided for attachment to the fluid chamber as well as for a mechanical contact with the bar stock to be inspected. Further, the invention relates to a method for coupling a US test probe to a bar stock with a cross section that is, for example, round, oval or polygonal, as well as to a use of a wear base.

Various ultrasonic test probes with a fluid chamber - hereinafter referred to as US test probes - are known from the prior art. Replaceable wear bases prevent a direct contact of the US test probe to the test object and additionally ensure a sufficient sealing of the fluid chamber. As a rule, it is actually desired that a certain portion of the coupling fluid escapes between the wear base and the test object so that the friction between the test object and the wear base is reduced. However, the escape of the coupling fluid from the fluid chamber has to take place in a defined manner in order to minimize disturbances during the inspection, to save coupling fluid and to prevent an interruption of the flow of coupling fluid. To this end, for bar stock with round cross sections, for example, a separate wear base is provided in the prior art for each test object radius, which comprises a contact surface that is adapted to this test object radius.

On the one hand, wear bases are known from the prior art that have a concave contact surface whose radius is exactly matched to the radius of the test object. They are pressed onto the test object in a positive manner. What is disadvantageous about this design is that only very limited differences in radii can be covered with these wear bases. For a large number of test objects having different radii, it is necessary to retool the US test probe each time.

Furthermore, wear bases are known which have a contact surface that, in cross section, is prismatic. The prismatic design of the contact surface yields a larger range of radii to be covered; however, depending on the radius of the test object, openings of various sizes form at the end of the prism which have to be closed in each case by constructional measures.

It is the object of the invention to provide an improved wear base. In particular, the object is to avoid retooling the test probe if different test objects, particularly bar stock with different radii, are to be inspected.

The object of the present invention is accomplished by a wear base according to claim 1, a US test probe according to claim 10, a method for the inspection of bar stock according to claim 11 as well as by a use for a wear base according to claim 13. Advantageous embodiments become apparent from the dependent claims, the following description and the Figures. However, the individual features of the embodiments described are not limited thereto, but may be combined with one another and with other features to constitute other embodiments.

A wear base for attachment to a US test probe is proposed, wherein the US test probe is provided for the ultrasonic inspection of bar stock with, for example, a round, oval or polygonal cross section. The US test probe comprises a fluid chamber which, in the operational state of the US test probe, is filled with a coupling fluid or through which this coupling fluid flows. The wear base is provided for attachment to the fluid chamber as well as for a mechanical contact with the bar stock to be inspected and comprises a base block. The base block in turn forms at least one contact surface for a mechanical contact with the bar stock to be inspected, the contact surface having a curved portion. At least one passage opening for the coupling fluid is disposed in the contact surface, the wear base comprising at least one spring member for the adaptive matching of a radius of curvature of the curved portion of the contact surface of the base block to a radius of the bar stock to be inspected.

In inspection systems known from the prior art, the change of the bar stock to be inspected to a different radius requires a change of the wear base at the same time, since that is designed only for a certain radius. The proposed wear base is advantageous in that it covers a broad range of test object radii, thus rendering a retooling process in case of a change of the test object radius superfluous in many cases. By pressing the US test probe with the proposed wear base onto the bar stock, the contact surface of the wear base adapts to the surface over a wide range of test object radii to the bar stock. It is further advantageous that the wear base can be used also in the case of large tolerances of the radius of the bar stock to be inspected. The wear base can be used even in the case of test object radii changing along a bar stock, for example in a transition of the diameter or in the case of a conical test object.

The coupling fluid can be water, an oil, an emulsion or a preferably aqueous solution. The coupling fluid is advantageously fed into the fluid chamber of the US test probe and supplied to the bar stock through the passage opening. Preferably, the passage opening is designed as a cut-out extending through the wear base. The acoustic coupling of US test probes to a test probe by means of a coupling fluid is sufficiently known to the experts, and is therefore not explained in any more detail here.

The base block within the sense of the invention is that part of the wear base which undergoes a shape change during the adaptive matching of the contact surface to the radius of the bar stock.

The contact surface placed on the bar stock is preferably wetted with the coupling fluid, i.e. friction between the contact surface and the bar stock is reduced by the coupling fluid. Nevertheless, a direct mechanical contact between the contact surface and the bar stock can occur, particularly due to bumps or due to an interruption of the lubricating film formed by the coupling fluid. Depending on the geometry of the bar stock and the geometry of the contact surface, the contact surface comes into contact with the bar stock only with some sections, in particular only with at least one part of the curved portion.

The spring member can be configured as a leaf spring, spiral spring or other spring- elastic member. Advantageously, at least one spring member configured as a leaf spring is embedded in the base block. In another embodiment, it is provided that several spring members are disposed on or in the base block. In an exemplary embodiment, it is provided that the base block is divided into discrete portions and a spring member is allocated at least to each portion. Preferably, the portions can be moved independently of one another. In one embodiment, it is provided that the wear base comprises a preferably separately formed frame, in particular for mechanical attachment to the US test probe.

It is provided in another embodiment that the spring member is coupled to the frame. Preferably, the spring member is welded to the frame. It is moreover advantageous if the spring member is screwed or glued to the frame. In another variant, it is provided that at least the spring member and the frame are surrounded by a further material connecting the frame and the spring member. It is provided in another embodiment that the spring member does not touch the frame.

In one embodiment, it is provided that the base block comprises at least one wear member. In one embodiment, the wear member is a rod-shaped member which extends longitudinally through the base block, preferably in the direction in which the bar stock is passed through under the US test probe. Particularly preferably, at least a portion of the wear member protrudes over the contact surface. Further preferably, it is provided that the wear member ends flush with the contact surface, preferably, the contact surface encloses a part of the surface of the wear member.

The wear member prevents the contact surface from wearing down too quickly.

Particularly preferably, the wear member comprises a more abrasion-resistant material than the material of the base block or the contact surface surrounding the wear member. In one embodiment, it is provided that the wear member comprises a metallic material. Preferably, the wear member comprises at least one material selected from a group comprising steel, ceramics and hard metal. The material is preferably selected depending on the test object.

It is provided in a preferred embodiment that the wear member is mechanically attached to the spring member. Preferably, the wear member is caulked, welded or glued to the spring member. The attachment of the wear element to the spring member is advantageous in that a continuous contact at least between the test object and the wear element is ensured. Particularly preferably, the base block comprises two, three or more than three wear members. It is provided in a further embodiment that the wear member and the spring member are formed as a single piece. In a preferred embodiment, it is provided that the base block comprises contact wings. Preferably, the contact wings extend away from the frame, starting at a frame-side base block portion. In particular, it is provided that the contact wings are disposed symmetrically on the frame-side base block portion, seen in a cross section perpendicular to the longitudinal axis of the wear element. The contact wings are connected to the frame-side base block portion. Preferably, the contact wings are integrally connected to the base block. In another embodiment, the contact wings are connected to the base block in a substance-to-substance connection.

Furthermore, it is provided in one variant that the contact wings comprise at least one material different from the rest of the base block.

Within the sense of the invention, the longitudinal axis of the wear member is that axis in whose direction the bar stock is moved under the US test probe during an inspection, or in which the US test probe is moved over the bar stock.

At least partially, the contact wings can be moved independently of the frame-side base block portion. Preferably, notches extend along the base block between the frame-side base block portion and the contact wings. The notches allow for a freedom of movement of the contact wings towards the frame-side base block portion.

In a preferred embodiment, it is provided that the spring member is at least partially disposed in the contact wings, or extends into the contact wings. Preferably, the spring member biases the contact wings.

The contact wings comprise at least a part of the contact surface on the side facing away from the US test probe. Preferably, the contact wings comprise at least a part of the curved portion of the contact surface. Particularly preferably, the radius of curvature of the curved portion is bent in the unloaded state to the minimally provided radius of curvature, or smaller, by the bias of the spring member. For example, the contact wings - particularly the outer edges of the contact wings - in an unloaded operational state are "bent away" from the frame-side base block portion by the spring member in such a way that the curved portion has a radius of curvature which matches the smallest radius of the bar stock for which the wear base is provided.

The contact wings enable a simpler adaptation of the contact surface of the base block to the test object. If the wear base is placed on a bar stock with a larger radius, the wings bend in the direction of the frame, and the radius of curvature of the curved portions becomes larger. When the curved portion, or the contact wings, are "bent open", then, for example, an angle of the notch between the contact wings and the frame-side base block portion becomes smaller.

The contact wings are not an absolute requirement for designing the wear base to be adaptable to different radii. However, an embodiment with contact wings makes a broad range of test object radii possible to which the wear base can be adapted. In an embodiment without contact wings, the adaptability, i.e. the range of test object radii, is primarily determined, for example, by the deformability of the base block material.

In one embodiment, it is provided that the base block comprises a rubber-elastic material. Preferably, a material is selected which ensures a high degree of toughness with an elastic deformability at the same time. Particularly preferably, the base block comprises at least one material selected from a group comprising

poly(organo)siloxanes and thermoplastic materials.

Furthermore, a US test probe for the inspection of bar stock is proposed, wherein the US test probe comprises at least one US transducer and a fluid chamber for a fluid couplant, wherein an above-described wear base can be replaceably attached to the fluid chamber in such a way that the fluid chamber and the passage opening of the wear base are connected in a communicating way.

The attachment of a wear base according to the invention to the US test probe reduces the wear on the US test probe. Moreover, the proposed wear base shortens the retooling times in a series of inspection runs because the wear base only needs to be replaced if completely worn out. If the bar stock is exchanged for one with a new or other radius, retooling is completely superfluous.

Furthermore, a method is proposed for coupling a US test probe to a cylindrical bar stock, comprising the following steps:

Providing a US test probe, which comprises at least a transmitting element, a receiving element and a fluid chamber for a fluid couplant, wherein an above- described wear base is attached to the fluid chamber in such a way that the fluid chamber and the passage opening of the wear base are connected in a communicating way;

Bringing the curved portion of the contact surface of the wear base of the US test probe into contact with the bar stock, wherein the wear base is pressed onto the bar stock in such a way that the radius of the contact surface of the wear base is adapted to the radius of the bar stock by means of the spring member in the base block of the wear base.

In one embodiment, it is provided that the fluid chamber of the US test probe is filled with the couplant or that this couplant flows through it.

Furthermore, it is proposed to use the above-described wear base for an adaptation of a test probe to bar stock with different radii. For example, the wear base can also be used for test objects that have a radius that changes over their length.

In particular, it is provided that the wear base is used for providing a seal between a fluid chamber of a US test probe and a bar stock. In contrast to wear bases known from the prior art, the proposed wear base ensures an optimal seal of the fluid chamber even in the case of a variable radius of the bar stock to be inspected or of large tolerances. The intended escape of the coupling fluid between the wear base and the bar stock can be controlled and preferably regulated via the contact pressure of the US test probe against the bar stock.

Furthermore, a method for producing a wear member as described above is proposed : a skeleton is formed which comprises at least one frame, preferably consisting of metal, preferably of stainless steel. The frame is configured in such a way that, preferably, it can be directly connected to the fluid chamber of a US test probe. Spring members, preferably leaf springs, are fastened to this frame. These leaf springs are preferably fastened in such a way that they bias the base block, preferably the contact wings, in such a way that the curved portion of the contact surface in the unloaded state has a radius of curvature which is equal to or less than that of the smallest radius of the bar stock to be inspected. Wear members are attached to these leaf springs. These wear members are preferably manufactured from a material with a Brinell hardness of at least about 200 HB, preferably about 200 HB to about 400 HB.

Where the term "about" is used in the present invention, this specifies a tolerance range which is common in the present field. In particular, the term "about" is to be understood to mean a tolerance range of up to +/- 20%, preferably up to +/-10%.

The skeleton is inserted into a die. In the die, the skeleton is encased with a plastic material at least to a large extent. Almost all primary forming processes known from the prior art today are suitable processes. Injection molding or also conventional casting, for example, should be mentioned by name. In this case, the design of the die according to the prior art allows for the primary forming process.

Other advantageous embodiments become apparent from the following drawings. However, the developments depicted therein are not to be construed to be limiting; rather, the features described therein can be combined with one another and with the above-described features to constitute further embodiments. Furthermore, it should be noted that reference numerals indicated in the description of the Figures do not limit the scope of protection of the present invention but merely refer to the exemplary embodiments shown in the Figures. Identical parts or parts that have the same function have the same reference numerals below. In the Figures:

Fig. 1 : shows a schematic view of a wear base;

Fig. 2: shows a section through the wear base according to Fig. 1; and

Fig. 3 : shows a sectional view of another embodiment of a wear base.

Fig. 1 shows a schematic view of a wear base 1. The wear base 1 is attached to a US test probe 2. With the wear base 1, the US test probe 2 is pressed onto a cylindrical bar stock 3.1, 3.2 to be inspected. As is schematically indicated, the wear base 1 is able to adapt to different test object diameters.

The US test probe 2 comprises at east one ultrasonic transducer 9 which enables the transmission and reception of ultrasound. The ultrasound is coupled into the bar stock 3 via a coupling fluid, which is not shown here and which is fed into a fluid chamber 10. For this purpose, the wear base 1 comprises a passage opening 5 for the coupling fluid. Advantageously, the coupling fluid exits with a defined flow between the wear base 1 and the bar stock 3 in order to reduce the friction between the wear base 1 and the bar stock 3 and/or to cool the wear base 1 during an inspection.

Furthermore, a base block 6 consisting of a rubber-elastic thermoplastic material is apparent from Fig. 1, which comprises a frame-side base block portion 13 as well as contact wings 12. The contact wings 12 are integrally connected to the frame-side base block portion 13.

The frame-side base block portion 13 is provided to be mechanically fixed to the US test probe 2, with this connection preferably being configured to be fluid-tight. For this purpose, the frame-side base block portion 13 preferably comprises a high degree of dimensional stability which can be obtained, for example, by reinforcement by means of a metallic frame 4 apparent from Fig. 2, which is embedded into the material of the frame-side base block portion 13. Such a frame 4 preferably has a rectangular basic shape and is configured to be plane, for example. For example, metallic round stock (e.g. wire with a sufficient diameter) or flat stock has proved itself for forming the frame 4. In this case, the frame 4 preferably encloses the passage opening 5, which is apparent from Fig. 1 and which is formed in the wear base 1.

In order to illustrate the geometry of the contact wings 12, which are also included in the wear base 1, it shall be assumed, with reference to Fig. 2, that the wear base 1 was configured as a rectangular block in which the passage opening 5 extends in the direction of the Y axis indicated in Figs. 1 and 2. In the direction of the Z axis, which is also indicated and which is collinear with the axis of symmetry of the bar stock 3 to be inspected, a partially cylindrical cut-out is incorporated into the block, so that the wear base forms a surface portion with a constant radius of curvature R that extends in the direction of the Z axis over the entire length of the block. This surface portion 7.1 is in that case provided for a mechanical contact with the bar stock to be inspected and thus constitutes the contact surface 7 of the wear base 1. This is explained once again below with reference to Figure 2.

The contact wings 12, which also extend in the direction of the Z axis in the Figures 1 and 2, preferably consist of the same material as the frame-side base block portion 13 and are mechanically connected therewith. Between the contact wings 12 and the frame-side base block portion 13, notches 14 preferably having a triangular cross section are incorporated into the long sides of the "block" that extend over its entire length in the Z direction. This results in an elastic deformability of the contact wings 12 in the direction of the Y axis in the Figures 1 and 2. If the contact wings 12 are deformed in the direction of the Y axis, the radius of curvature R of the contact surface 7 is increased at the same time, whereby the contact surface 7 is able to adapt to the geometry of the bar stock to be inspected.

As was already mentioned, the base block 6, and particularly the contact wings 12, comprise a contact surface 7 on the side facing away from the US test probe. The contact surface 7 comprises a curved portion 7.1 which rests on the bar stock 3 largely with its entire surface. In the case of larger test object radii, the contact wings 12 are deformed in the direction of the US test probe 2 and the radius of curvature of the curved portion 7.1 is increased.

Fig. 2 shows a schematic cross-sectional view of the wear base 1 from Fig. 1.

Different bar stocks 3.1 and 3.2 with different radii Ri and R ₂ are indicated. The wear base 1 is pressed onto the bar stock 3 with a force F. The contact wings 12 are elastically deformed by the force F or the corresponding counter force of the bar stock 3, until the contact surface 7, particularly its curved portion 7.1, rests on the bar stock 3 largely with its entire surface. In this case, the elasticity, which is inherent to the elastic material from which the base block 6 is made and from which a restoring force in the undeformed rest position results, acts as the spring member. In the example shown here, the wear base 1 is pressed onto the bar stock 3 in such a way that the radius of curvature R of the curved portion 7.1 largely adopts the radius RI of the bar stock 3.1. In a preferred development shown in Figure 2, the base block 6, which is preferably configured as a single piece, comprises at least one, but preferably several spring members 8 embedded into the contact wings 12. They can be configured as curved metallic single- or multi-part leaf springs and consist, for example, of a spring steel. In particular, the curvature of the spring members 8 can be adapted to the radius of curvature of the curved surface portion 7.1 of the contact surface 7. The at least one spring member 8 is biased and, in the unloaded state of the base block 8, forces the curved portion 7.1 of the contact surface 7 into a minimum radius of curvature R. If the US test probe 2 is pressed onto the surface of the bar stock 3 to be inspected, the separately formed at least one spring member 8 produces an additional restoring force which causes a good positive fit between the curved surface portion 7.1 of the contact surface 7 and the surface of the bar stock 3. In this way, the optional at least one spring member 8 improves the seal of the fluid chamber 10 of the test probe 2 against the bar stock 3 to be inspected.

Particularly preferably, at least two spring members 8 are provided which are connected to form a frame by means of at least two preferably metallic

reinforcements that substantially extend in the direction of the Z axis and have, for example, the form of round or flat steels. This frame is embedded into the material of the contact wings 12 as well as, optionally, of the frame-side base block portion 13 of the base block 6 and encloses the passage opening 5 for the coupling fluid formed in the base block 6. Such a frame, which is to be considered optional, provides for mechanical stiffening of the contact wings 12, in particular in their middle area, relative to the Z axis. This results in an even more improved seal of the passage opening 5 when the US test probe 2 is placed on the surface of the bar stock 3 to be inspected.

Furthermore, it can be seen that in the exemplary embodiment according to Figure 2, the contact wings 12 each comprise at least one, but preferably several optional metallic wear members 11. In this example, the wear members 11 are mechanically connected to the spring member 8, e.g. by positive or substance-to-substance fit. However, an embedment of the wear members 11 into the material of the contact wings 12 can possibly be sufficient. It can also be clearly seen that those wear members 11 that end flush with the contact surface 7 are pressed against the bar stock 3. In the embodiment shown in Fig. 2, the frame 4 is embedded in the frame-side base block portion 13. The frame 4 provides for sufficient stability of the base block 1 and, by means of coupling elements 15, furthermore enables an attachment of the base block 1 to the US test probe 2. The frame 4 and the spring member 8 are not directly interconnected in this case. Rather, it can be seen that the plane frame 4 and the spring members 8 are embedded, spaced apart, into the thermoplastic material from which the base block 6 is formed in one piece.

Fig. 3 shows another embodiment of a wear base 1 in a sectional view. The contact wings 12, in the direction of the X axis, are each divided into three wing portions 12.1, 12.2 and 12.3. They are mounted, for example, next to one another via a tongue-and-groove connection in such a way that they can be moved largely independently of each other in the direction of the Y axis. Spring members 15 that can be configured as spiral springs are respectively disposed between the frame 4 and the wing portions 12.1, 12.2 and 12.3. The spring members 15 are partially embedded into the rubber-elastic material of the base block 6 and brace themselves against the frame 4. If the wear base 1 is pressed against the bar stock 3.2 with the force F, the spring members 15 cause a discrete adaptation of the curved portion 7.1 of the contact surface 7 by an individual deflection of the discrete wing portions 12.1, 12.2 and 12.3 to the test object radius R2.

Furthermore, it can be seen in the embodiment shown in Fig. 3 that the wing portions 12.1 and 12.2 each have one ceramic wear member 11 per side. The spring members 15 press the wear members 11 indirectly, via the rubber-elastic material of the base block 6, onto the bar stock 3.2. In an embodiment which is not shown here, the spring members 15 are mechanically connected to the wear members 11.