GB2244780A

GB2244780A - A method and system for delivering an expansionary head

Info

Publication number: GB2244780A
Application number: GB9010930A
Authority: GB
Inventors: James Frederick Quirk
Original assignee: PHOENIX INSPECTION SYSTEMS LIM
Current assignee: PHOENIX INSPECTION SYSTEMS LIM
Priority date: 1990-05-16
Filing date: 1990-05-16
Publication date: 1991-12-11
Also published as: GB9010930D0

Abstract

An expansionary head in the form of a probe carrier (2) with spring mounted arms (4) is to be delivered into a bore (18) by a delivery system comprised of a storage tube (6) and guide means (10). The guide means has a guide surface (20) which has an increasing cross-sectional area, and is defined by the internal conical surface of a conical member (8) and the abutting internal surface of a guide tube (12). The guide tube (12) is split such that its peripheral dimensions can be varied. <IMAGE>

Description

A METHOD AND SYSTEM FOR DELIVERING AN EXPANSIONARY HEAD The present invention relates to a method and system for delivering an expansionary head.

It is known to inspect bores in shafts ultrasonically by moving a probe carrier carrying ultrasonic probes along the bore. For accuracy, the probe carrier needs to be centred within the bore irrespective of the size of that bore. This is achieved by providing the probe carrier in the form of an expansionary head. For example, the probe carrier may be provided with pneumatically actuated arms for engagement with the surface of the bore, which arms are extended once the carrier has been placed in the bore.

Alternatively, the probe carrier can be provided with spring loaded arms which are confined against their spring bias for introduction of the carrier into the bore and then engage the surface of the bore to centre the carrier therein.

At present, the probe carrier is delivered into the bore manually. With a spring action probe carrier, this involves confining the probe carrier in a storage tube which is aligned with the end of the bore, and then pushing the carrier out of the storage tube into the bore. To cope with bores with differing diameters, it is generally necessary to provide storage tubes with different diameters for the probe carrier.

According to a first aspect of the present invention there is provided a method of delivering or removing an expansionary head into or out of a recess, the method comprising the steps of providing a tubular storage member for receiving the head, the internal cross-sectional area of said tubular storage member being less than that of said recess, positioning hollow elongate guide means between said storage member and said recess such that an inner surface of said guide means forms a guide surface extending from said storage member to said recess, the guide surface having a first end portion adjacent to, and having substantially the same internal cross-sectional area as, the storage member, a second end portion adjacent to, and having substantially the same internal cross-sectional area as, the recess, and an intermediate portion joining said first and second end portions, the internal cross-sectional area of said intermediate portion progressively increasing from that of said first end portion to that of said second end portion, and propelling said head out of said storage member or recess through said guide means, and into said recess or storage member.

In the method defined above, the head may be propelled by way of push rods and the like. Because the head is being propelled along a guide surface whose area progressively increases, its expansion is controlled.

This enables the method to be used, for example, in an automatic delivery system.

The expansionary head may be a probe carrier. The recess into or out of which the head is to be delivered may comprise a bore, for example provided to extend axially of a shaft.

In this embodiment, the guide surface may be arranged to extend into said bore.

In a preferred embodiment, the cross-sectional area of said second end portion of the guide surface, and hence the maximum cross-sectional area attained by said guide surface, is variable. This enables adjustment of the guide surface to fit varying sizes of recess.

The present invention also extends to a delivery system for use in delivering or removing an expansionary head into or out of a recess by the method defined above.

According to a further aspect of the present invention there is provided a delivery system for an expansionary head comprising a tubular storage member for receiving and confining the head, and guide means co-operable with said storage member and arranged to provide a guide surface which extends away from said storage member and has an increasing cross-sectional area whereby controlled expansion of said expansionary head, is enabled, wherein the maximum cross-sectional area attained by said guide surface is variable.

Because the maximum cross-sectional area attained by said guide surface is variable, the delivery system can be used to controllably deliver an expansionary head into recesses or bores having differing cross-sectional areas.

The provision of a guide surface with a variable maximum cross-sectional area may be achieved in a number of ways. For example, the guide means may comprise a guide member formed of a plurality of interengaged ring members each having an internal cross-sectional area greater than that of an adjacent ring member and arranged to be telescoped one within the other. The ring members may be arranged to be movable from a first end position in which they are telescoped to an extended position defining a generally conical guide surface.

The ring members are also enabled to take up a number of intermediate positions in which the length and maximum cross-sectional area of the conical guide surface differs.

In use, the base end of the conical guide surface may be arranged to abut or engage in the end of a bore into which the expansionary head is to be delivered.

In an alternative embodiment, the guide means may comprise a guide member generally in the form of a cone having an internal, conical guide surface. Slits or other adjustment means may be provided to extend axially of the conical guide surface to enable its overall internal area to be adjusted.

In a preferred embodiment in which an expansionary head is to be delivered into a bore, said guide means comprises a generally conical guide member and a guide tube. The guide tube is arranged to extend within the conical member to define a guide surface therewith. In this respect, an end of the guide tube is arranged to contact the internal surface of said conical guide member to thereby determine the maximum cross-sectional area of the guide surface. This maximum cross-sectional area is varied either by choosing guide tubes with differing diameters or by adjusting the diameter of the guide tube.

In a preferred embodiment the tubular storage member, and the guide surface are substantially circular in cross-section.

In a preferred embodiment, the conical guide member of said guide means is affixed to, or formed in one piece with, said tubular storage member.

The diameter of said guide tube is preferably adjustable, for example by providing one or more axial splits therein.

In a preferred embodiment the guide tube is provided with external engagement means for engagement with an end of a member in which said bore or recess is provided. For example, a bore into which the head is to be delivered by the delivery system may extend axially of a shaft.

Preferably, the expansionary head comprises a probe carrier for a number of ultrasonic probes. Outwardly biased spring arms may be provided on said probe carrier.

In an embodiment, the delivery system is provided in an automatic machine for the ultrasonic testing of workpieces.

The invention also extends to an automatic testing machine comprising a delivery system as defined above.

Embodiments of the present invention will hereinafter be described with reference to the accompanying drawing, in which: Figure 1 shows a longitudinal section through a delivery system of the invention arranged to deliver a probe carrier into the bore of a shaft, and Figure 2 shows an end view of a guide tube of the delivery system of Figure 1.

It is convenient to inspect bores in shafts, or in other workpieces, for cracks and other imperfections by ultrasonic means. In this respect, ultrasonic probes are moved through the bore to perform the testing. For accuracy, the probes are carried on a probe carrier which is arranged to be centred within the bore. A delivery system for such a probe carrier is illustrated in Figure 1.

In the embodiment illustrated the probe carrier 2 is provided with a number of spring mounted arms 4 biased outwardly whereby the probe carrier 2 may be centred within a bore. Probes (not shown) are carried by the probe carrier 2. Initially the probe carrier 2 is confined- within a tubular storage member 6 of substantially circular cross-section, whose internal diameter is less than that of a bore 18 of a shaft 1, into which bore 18 the probe carrier 2 is to be delivered. The storage tube 6 therefore pushes the arms 4 towards the carrier 2 against the action of the springs. The storage tube 6 is fixed at one end to a substantially circular cross-section conical member 8 of guide means generally referenced 10. The guide means 10 also includes a guide tube 12.It will be seen that the guide tube 12 has a part circular periphery which is split axially as is indicated at 14. The guide tube 12 is preferably a thin walled metal tube having a diameter which is approximately that of the bore 18. However, because the tube 12 is split at 14, it can be inserted into the bore 18 and its periphery adjusted to fit exactly within the bore 18. The axial extent of the guide tube 12 within the bore 18 is determined by engagement means in the form of radially extending lugs 16 formed externally of said tube 12 and arranged to abut the end of the shaft 1.

The storage tube 6 and the attached conical member 8 form a delivery system for the probe carrier which is mounted on a machine bed (not shown). The shaft 1 is also supported on the machine bed, and supports (not shown) are adjusted such that the tube 6 and the conical member 8 are generally axially aligned with the bore 18 in the shaft 1. The probe carrier 2 is positioned within the storage tube 6. The delivery system is spaced from the bore 18 so that the guide tube 12 may be engaged within its end such that its lugs 16 abut the end of the shaft 1. The tube storage 6 and the conical member 8 are then moved axially towards the tube 12 until the free end of the tube 12 contacts the inner surface of the conical member 8 whereby further axial movement of the delivery system is not possible.It will be appreciated that at this position the internal conical surface of the member 8 and the abutting internal surface of the guide tube 12 together define a guide surface indicated at 20 for the probe carrier 2.

Push rods (not shown) are then used to push the probe carrier 2 axially through the guide means 10 and into the bore 18.

It will be seen that the probe carrier 2 is moved along a guide surface 20 which has an increasing cross-sectional area, through the rest of the guide tube 12 and into the bore 18. This enables the spring mounted arms 4 to move outwardly under the action of the springs such that controlled expansion of the cross-sectional area of the probe carrier 2 is enabled.

It will be appreciated that the controlled expansion of the probe carrier 2 takes place without the probe carrier having to negotiate any step changes in diameter.

The guide surface 20 for the probe carrier 2 is defined within said guide means 10 by a first end portion of the conical member 8 which is adjacent to and has the same internal diameter as the storage tube 6.

The guide surface 20 also has a second end portion provided by the internal surface of the guide tube 12 which is adjacent to and of the same internal diameter as the end of the bore 18. Intermediate the first and second end portions, the internal diameter of the guide surface 20 progessively increases from that of the storage tube 6 to that of the guide tube 12.

It will be appreciated that the delivery system shown in Figure 1 can be utilised to deliver the probe carrier 2 into bores 18 of differing cross-sections. In this respect, a single guide tube 12 could be provided and enabled to take up different internal diameters in dependence upon the diameter of the bore 18. It will be appreciated that the diameter of the guide tube 12 determines the axial extent to which the guide tube 12 can extend into the conical member 8 and thereby determines the maximum diameter defined by the guide surface 20. Alternatively, a series of guide tubes 12 of differing diameters may be provided to enable the controlled delivery of the probe carrier 2 into bores of differing diameter.

The probe carrier 2 illustrated is a particular form of spring action carrier designed for carrying ultrasonic probes. However, it will be appreciated that the delivery system illustrated may be employed to deliver any expansionary head into any recess or bore in a controlled manner. The delivery system provides a smooth guide surface 20 enabling the controlled expansion of the head without any step changes. Not only does the delivery system thereby enable the smooth delivery of the head into the recess or bore, but it also enables the head to be moved out of the recess or bore and back into its storage member. The expansionary head may be propelled into and out of the recess or bore by any suitable means. In the embodiment illustrated, push rods are preferred. These may be arranged to extend along the split 14 of the guide tube 12, and this split also enables nylon supports (not shown) to be provided on the rods and accommodated within the split 14.

It will be appreciated that further modifications and alterations may be made to the present invention within the scope of this application.

Claims

1. A method of delivering or removing an expansionary head into or out of a recess, the method comprising the steps of providing a tubular storage member for receiving the head, the internal cross-sectional area of said tubular storage member being less than that of said recess, positioning hollow elongate guide means between said storage member and said recess such that an inner surface of said guide means forms a guide surface extending from said storage member to said recess, the guide surface having a first end portion adjacent to, and having substantially the same internal cross-sectional area as, the storage member, a second end portion adjacent to, and having substantially the same internal cross-sectional area as, the recess, and an intermediate portion joining said first and second end portions, the internal cross-sectional area of said intermediate portion progressively increasing from that of said first end portion to that of said second end portion, and propelling said head out of said storage member or recess through said guide means, and into said recess or storage member.

2. A method as claimed in Claim 1, wherein said head is propelled by way of push rods.

3. A method as claimed in Claim 1 or 2, wherein said expansionary head is a probe carrier, and said recess into or out of which the head is to be delivered comprises a bore.

4. A method as claimed in Claim 3, wherein said guide surface is arranged to extend into said bore.

5. A method as claimed in any preceding claim, wherein the cross-sectional area of said second end portion of the guide surface is variable, and further comprising adjusting the guide surface to fit the size of the recess.

6. A delivery system for use in delivering or removing an expansionary head into or out of a recess by the method as claimed in any preceding claim.

7. A delivery system for an expansionary head comprising a tubular storage member for receiving and confining the head, and guide means co-operable with said storage member and arranged to provide a guide surface which extends away from said storage member and has an increasing crosssectional area whereby controlled expansion of said expansionary head is enabled, wherein the maximum crosssectional area attained by said guide surface is variable.

8. A delivery system as claimed in claim 7, wherein said guide means comprises a guide member formed of a plurality of interengaged ring members each having an internal crosssectional area greater than that of an adjacent ring member and arranged to be telescoped one within the other, the ring members being movable between a first end position in which they are telescoped and an extended position defining a generally conical guide surface.

9. A delivery system as claimed in Claim 7, wherein said guide means comprises a guide member generally in the form of a cone having an internal, conical guide surface.

10. A delivery system as claimed in Claim 9, wherein slits or other adjustment means are provided to extend axially of the conical guide surface to enable its overall internal area to be adjusted.

11. A delivery system as claimed in claim 7, wherein said guide means comprises a generally conical guide member and a guide tube, the guide tube being arranged to extend within the conical member to define a guide surface therewith.

12. A delivery system as claimed in claim 11, wherein an end of the guide tube is arranged to contact the internal surface of said conical guide member to determine the maximum cross-sectional area of the guide surface.

13. A delivery system as claimed in Claim 11 or 12, wherein the maximum cross-sectional area of said guide surface is varied either by using guide tubes with differing diameters or by adjusting the diameter of the guide tube.

14. A delivery system as claimed in any of Claims 9 to 13, wherein the conical guide member of said guide means is affixed to, or formed in one piece with, said tubular storage member.

15. A delivery system as claimed in any of Claims 11 to 14, wherein the diameter of said guide tube is adjustable.

16. A delivery system as claimed in any of Claims 11 to 15, wherein the guide tube is provided with external engagement means for engagement with an end of a member in which said bore or recess is provided.

17. A delivery system as claimed in any of claims 7 to 16, wherein the tubular storage member, and the guide surface are substantially circular in cross-section.

18. A delivery system as claimed in any one of Claims 7 to 17, wherein the expansionary head comprises a probe carrier for a number of probes.

19. A delivery system as claimed in Claim 18, wherein said probes are ultrasonic.

20. An automatic machine for the testing of workpieces incorporating a delivery system as claimed in any of Claims 7 to 19.

21. A method of delivering or removing an expansionary head into or out of a recess substantially as hereinbefore described with reference to the accompanying drawing.

22. A delivery system for an expansionary head substantially as hereinbefore described with reference to the accompanying drawing.

23. An automatic machine for the testing of workpieces substantially as hereinbefore described with reference to the accompanying drawing.