| US4786612A | 1988-11-22 | |||
| US4678148A | 1987-07-07 | |||
| GB1522724A | 1978-08-31 |
| 1. | projection conforming in its external shape and alignment. |
| 2. | ith, and being of such size as to be insertable into and. |
| 3. | fit within the end of one of said paβsagways in one of said. |
| 4. | tubular elements, whereby said connector means, when brought. |
| 5. | into coaxial abutment with the end of each tubular element β and with each of its projections coaligned with one of the 7 passageways in said element, when each said elements and 8 said connector means are pushed together axially, all said 9 projections are inserted into and βlideably fitted within 0 the correspondingly aligned passageways in the respective 1 element to bring said short tubular section of the connector means into abutment with the ends of the tubular elements, thereby to connect both tubular elements through said connector means. |
| 6. | 2 A high strength thin walled plastic tube and connector combination, said combination comprising: A. A thin walled tubular element comprised of a high strength linear aromatic polymer, said element having a predetermined external diameter, and a matrix of walls extending internally for the length of the element, each wall of the matrix extending radially inwardly from a predetermined'line along the inside of the tubular element wall and joined with the other matrix walls along the element axis, thereby to provide internal support for the tubular element against bending, said matrix walls and the ,9 P projections coaligned with one of the passageways in said element, when said element and said connector means are pushed together axially, all said projections are inserted into and slideably fitted within the correspondingly aligned passageways to bring said short tubular section of the connector means into abutment with the end of the tubular element. |
| 7. | 3 The combination as described in Claim l wherein the end of the section from which inner portions of the tube will extend to form, with the matrix wall extensions, said 4 In combination: A. A thin walled tubular element comprised of a high strength linear aromatic polymer, said element having a predetermined external diameter, and a matrix of walls extending internally for the length of the element, each wall of the matrix extending radially inwardly from a predetermined line 'along the inside of the tubular element wall and joined with the other matrix walls along the element axis, thereby to provide internal support for the tubular element against bending, said matrix walls and the inside of the tube element defining a plurality of similar passageways within the tubular element; B. A member to which said tubular element is to be fixedly secured; and C* Means to secure said tubular element to said member, caid means comprising a plurality of parallel projections extending from said member, each of said projections in crosssection comprising a circular sector, with the external walls of all said projections being encompassed by a common circle, said circle being slightly less in diameter than the diameter of the inside wall of th tubular element and each of said projections being spaced from each other and of such size and configuration as to be slideably insertable into one of said passageways in the tubular element, whereby when all said projections are so inserted into the passageways in said tubular element, the latter becomes fixedly secured to said member. |
| 8. | 5 The combination as described in Claim 4 wherein adhesive is applied to the outsides of said projections prior to their being inserted into the passageways. |
| 9. | The combination as described in Claim 2 wherein th tubular element and connector means are so dimensioned that when brought together with the projections inserted in the passageways, the cylindrical section of the connector means and the wall of the tubular element are brought into flush abutment. \6. |
DESCRIPTION FIE D.-OF THE TUVENTIOM
This invention relates broadly to the field of structural elements, and particularly to tubular elements comprised of extrusions of short carbon fiber resins and connectors injection molded of similar resins.
BAGKCROΌKD OF THE IWVEMTIQW
Considerable attention has been devoted by industry in general to utilizing recently developed high strength plastics, such as polyetheretherketone (PEEK) , a short carbon-fiber resin with surface hardness and elongation percentage surpassing quality steel performance modulus, as a substitute for metals, such as steel and aluminium, in various parts and items produced by the aircraft/aerospace industry. While plastics composites have been recognized as tttilisable to produce substitutes for metal parts, the manner in which such plastics have been employed has not been- such as properly to utilize a potential of such recently developed short carbon fiber resins.
Th s, tubes employed in structural elements for bicycles, airfraraβs and the like, generally have been fabricated by applying a malleable resin impregnated fabric in wires to a mandril or form for shaping. Such a process has been time consuming and has not produced the most
sectors spaced apart from each other by the thickness of the radial walls of the matrix in the tube with the diameter of the circle in which lie the outer walls of said sectors, being sufficiently smaller than the inside diameter of the tubular element to enable the extensions from the circular section to be pushed in into the tube when properly aligned so that the radial matrix walls may pass into the spacing between the adjacent sectors,
Where two tubular elements are to be joined, auch projections may extend from each end of the tubular section of the connector. However, where a tubular element is to be connected to a joint, a wall or some other member, the latter desirably will have cast or molded into it a short cylindrical section with the sector extensions similarly formed, as described above, so that the end of the tubular element to be attached may be slipped over said sector projections to effect the desired joinder of the tubular element with the remainder of the structure carrying the tubular section and its projections. It would be possible, however, to eliminate the tubular section portion altogether from the member and instead, have the desired projections molded to extend directly form the member so that the tubular element when slipped over the projections would abut preferrably an annular area of the member.
Each connection may be secured against withdrawal of the projections by the application to the outside of at least a portion of each projection of a light coating of a
2.1 str
described, it is preferably injection molded of the same PEEK or other similar resin. The is formed with a short cylindrical section 34, desirably having a wall 35 which may be twice as thick as the walls 24 of the tubes 18 and 20. Extending from each end of the short cylindrical βection34 are a plurality of projections 36a, 36b and 36c, each of which in erosβ-section is aleo in the conf guration of a circular sector, but sufficiently smaller than the passageways 32a, 32b and 320 to be insertable therein respectively in a close fit. In order to be so insertable, each of the projections 32a, 32b and 32c must be laterally spaced from its adjacent projections by a distance slightly greater than the thickness of the walls 28a, 28b and 28c respectively. Desirably the circular shoulder 38 formed at each end of the cylinder section 34 around the bases of the projections 36a, 36b and 36c, is of the same height as the thickness of the wall 24 of each tube 18 and 20. Thereby, when the ends of tubes 18 and 20 are brought into axial alignment with the ends of the connector 22 and the projections 36a, 36b and 36c are pushed into the passageways 32a, 32b and 32c respectively, the outside of the wall 35 of the connector will be flush with the outside of the wall 24 of each tube 18, 20, as best shown in Fig. 3. It may also be observed from Fig. 3 that while normally the greatest weakness in a connected tube occurs at its connected end, beoauβe of the manner in which the tubes 18, 20 are
i
projections may be integrally cast or injection molded with either an anchoring portion 46 of the terminal 40, or the remainder 48 of the joint 42 as shown in Fig. 6.
Because of the strength and light weight of the tubing, it may also have application as bone replacement as shown in Pig. 7. Where used with a plastic joint 50, the projections 52a, 52b, 52c as may be cast or injection molded either as a part of a joint 50 or with a connector end 54 of the type shown in Figures 4, 5 and 6, as illustrated in Fig. 7. Similarly at the opposite end of the bone replacement tube 56, a connector end 58 may be molded or cast: to effect a connection.
From the foregoing it may be seen that tubing fabricated in accordance with the present invention may have many uses, and wide applications, particularly when employed in combinations ith connectors or terminal ends having the projections insertable into the ends of the passageways in the tubing. The tubing itself desirably may be extruded, but the connectors, because of their slotting between the projections, desirably should be injection molded, although they could also be extruded and then machined to the configuration shown in Fig. 4, or to any required con iguration.