A COMPOUND MEMBER AND METHOD OF DEPLOYMENT

Abstract: A compound member (2) is formed from at least two extendible, coilable members (2a) each of which is reversibly configurable between a coiled form and an extended form. The extendible, coilable members (2a) are arranged such on deployment from their coiled form to their extended form, they join or can be joined to form the compound member (2).

Description: A COMPOUND MEMBER AND METHOD OF DEPLOYMENT The present invention relates to a compound member and a method of deployment . In WO-A-88/08620 and WO-A-97/35706 , the entire disclosures of which are incorporated herein by reference, there are disclosed extendible, coilable members which are reversibly configurable between a coiled form and an extended form. A perspective view of an example of such a member 1 is shown in Fig. 1 in part coiled form la and part extended form lb. In the extended form, the member typically has a circular or near circular cross-section. Now, a circular or near circular cross-section is good for supporting or carrying anisotropic loads, but is not particularly good for supporting or carrying isotropic loads. Further, at the region of the transition between the coiled and extended forms, a relatively large amount of bending of the material of the member is required, which limits the rigidity of the material that can be used to form the member and also subjects the member to significant stress during deployment from the coiled to the extended form and vice versa. According to a first aspect of the present invention there is provided a compound member, the compound member being formed from at least two extendible, coilable members each of which is reversibly configurable between a coiled form and an extended form and which are arranged such on deployment from their coiled form to their extended form, said extendible, coilable members join or can be joined to form the compound member. The compound member can have a cross-sectional shape which is other than circular, so that, when arranged appropriately, the compound member can support or carry greater isotropic loads than an equivalent extendible, coilable member of circular cross-section in its extended form. The individual extendible, coilable members themselves need not have a circular cross-section. This in turn means that at the region of the transition between the coiled and extended forms, a relatively small amount of bending of the material of the member is required. This means that materials or greater rigidity can be used to form the member and also means that the member is subjected to less stress during deployment from the coiled to the extended form and vice versa. The extendible, coilable members are preferably arranged to join or be joined at or towards their respective edges. The extendible, coilable members may be provided with joining means at their edges to join the extendible, coilable members on deployment from their coiled form to their extended form. Said joining means may comprise complementary parts of a zip such that adjacent edges of the extendible, coilable members zip together on deployment of the extendible, coilable members from their coiled form to their extended form. According to a second aspect of the present invention, there is provided in combination, a compound member as described above and a drive mechanism for driving at least one of the extendible, coilable members from its coiled form to its extended form. The drive mechanism may comprise a worm gear and said at least one extendible, coilable member may have a rack for engagement by the worm gear. According to a third aspect of the present invention, there is provided a method of forming a compound member from at least two extendible, coilable members each of which is reversibly configurable between a coiled form and an extended form, comprising the steps of: deploying the extendible, coilable members from their coiled form to their extended form; and, joining the extendible, coilable members to form a compound member. The extendible, coilable members may join automatically on deployment from their coiled form to their extended form. The extendible, coilable members may be arranged such as to be deployed synchronously from two or more coils with provision to reversibly or permanently join said extendible, coilable members as they extend so as to form a compound member . The extendible, coilable members may be joined by means which include, but which are not be limited to, the attachment of zip fasteners along the edges of said members, the provision of protrusions, cavities or holes in said members such as to interlock with each other upon extension or the provision of separate locking devices such as clips or rivets, or the use of means such as welding or adhesive bonding to create a permanent joint between said members . The drive means mentioned above may be unidirectional, or reversible such that the compound member may be both extended and retracted by said means. Such means may include, but not be limited to, the provision of a rotating drum inside the coil, friction drives bearing on some part of the extended member or the provision of protrusions, cavities or holes on the surface of said member, into or onto which gears may engage to provide said means of extension or retraction. The means of joining said extendible, coilable members such as to form a compound member may be provided along a line removed from the point of natural tangential contact of said extendible, coilable members such as- to place the extendible, coilable members of the compound member in radial stress when in the extended state. One or more of the desired joints between the extendible, coilable members of such a compound member may be provided in the form of some type of hinge such that the hinged extendible, coilable members roll side by side into a single coil but upon extension articulate about the hinged edges in such a manner as to allow permanent or reversible joining along one or more of the seams to form the compound member. An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of an example of an extendible, coilable member which is reversibly configurable between a coiled form and an extended form, showing the member in part coiled form and part extended form; Fig. 2 is a cross-section through an example of a compound member according to the present invention; Fig. 3 is a section through raised blocks of the example of Fig. 1 showing them interlocking in the manner of a zip fastener; Fig. 4 is a side elevation of one member of the compound member of Fig. 2 and a drive mechanism for reversibly extending said member; Fig. 5 is an end view of a second example of a compound member according to the present invention; and, Fig. 6 is an end elevation showing an example of a compound member according to the present invention being formed from three coiled members. Referring to Fig. 2, there is shown a compound member 2 according to the present invention formed from three joined members 2a. Each of the members 2a may be manufactured and constructed in accordance with the teachings of WO-A-88/08620 or WO-A-97/35706 or may be of any other suitable form. The individual members 2a are joined at their edges by any suitable means which, preferably, allow the individual members 2a to be detached again. In the example shown, the individual members 2a are joined by means of raised blocks 2b provided at lines of tangent contact of each of the members, the blocks 2b being shown in more detail in Fig. 3. The blocks 2b interlock along the line of transition between the coiled and extended forms of each of the individual members 2a such that, when in the extended state, the individual members 2a are locked together in the manner of a zip fastener so as to form a compound member 2. The raised blocks 2b may be formed in such a manner as to interlock so as to prevent slippage in the plane of tangent contact at right angles to the axis of extension. Referring briefly to Fig. 6, the coils 6a formed by the individual members 2a in their coiled form are arranged about a suitable supporting structure (not shown) such that, when the individual members 2a are extended, the extended parts 6b of the individual members 2a come together to join at their edges to form the compound member 2. To assist m extension of the individual members 2a, at least one of the individual members 2a can be provided with a set of raised blocks 4b along its centre line as shown in Fig. 4. Preferably, all of the individual members 2a are provided with such raised blocks 4b along their respective centre lines. These raised blocks 4b provide a rack onto which a worm screw 4a can bear. For the sake of clarity, Fig. 4 shows only one of the individual members 2a, the others being equiangularly arranged around the worm screw 4a to engage therewith such that a compound member 2 is created upon extension of all of the individual members 2a. Any desired number of individual members 2a may be combined in any manner to create a compound strut 2 suitable for a given purpose. It should be noted that each of the members 2a may be manufactured and constructed in accordance with the teachings of WO-A-88/08620 or WO-A-97/35706 or may be of any other suitable form. As shown m Fig. 5, as an alternative to the joining of the individual members 2a at their edges, one or more flexible webs 5c may be provided at the edges of the individual members 2a to allow the joining of members other than at points of tangent or edge contact. The flexible webs 5c may have zips 5b along their free edges, the other edges of the webs 5c being attached to or integrally formed with the edges of the members 2a, such that closure of the zips forms the compound member 2 and places each individual member 2a under radial stress. It is expected that such compound members 2 will prove of utility in any area of engineering where it is desirable to provide long reach actuation from a relatively small package. Such areas include, but are not limited to, plant inspection and maintenance, the inspection and maintenance of pipelines, wells and bore holes, the clearing of blocked pipelines and the provision of linear actuators in robotic or positioning mechanisms. Any number of such compound members could be combined to form space frames or other temporary or permanent structures as desired for any given purpose . An embodiment of the present invention has been described with particular reference to the examples illustrated. However, it will be appreciated that variations and modifications may be made to the examples described within the scope of the present invention.

Claims: CLAIMS 1. A compound member, the compound member being formed from at least two extendible, coilable members each of which is reversibly configurable between a coiled form and an extended form and which are arranged such on deployment from their coiled form to their extended form, said extendible, coilable members join or can be joined to form the compound member. 2. A compound member according to claim 1, wherein the extendible, coilable members are arranged to join or are joined at or towards their respective edges. 3. A compound member according to claim 2, wherein the extendible, coilable members are provided with joining means at their edges to join the extendible, coilable members on deployment from their coiled form to their extended form. 4. A compound member according to claim 3 , wherein said joining means comprise complementary parts of a zip such that adjacent edges of the extendible, coilable members zip together on deployment of the extendible, coilable members from their coiled form to their extended form. 5. In combination, a compound member according to any of claims 1 to 4 and a drive mechanism for driving at least one of the extendible, coilable members from its coiled form to its extended form. 6. A combination according to claim 5, wherein the drive mechanism comprises a worm gear and said at least one extendible, coilable member has a rack for engagement by the worm gear. 7. A method of forming a compound member from at least two extendible, coilable members each of which is reversibly configurable between a coiled form and an extended form, comprising the steps of : deploying the extendible, coilable members from their coiled form to their extended form; and, joining the extendible, coilable members to form a compound member . 8. A method according to claim 7, wherein the extendible, coilable members join automatically on deployment from their coiled form to their extended form.

Inventors: DATON-LOVETT ANDREW JAMES, DATON-LOVETT, ANDREW, JAMES
Applicants: DATON LOVETT ANDREW JAMES, ROLATUBE TECHNOLOGY LIMITED, DATON-LOVETT, ANDREW, JAMES
Application year: 1999
Main classification: B65H75
IPC codes: B65H75, H01Q1