초록

A composite prepreg laminate such as a hat type-stringer is formed on a contoured mandrel using a combination of mechanical sweeping and vacuum forming.

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1. An apparatus for forming a composite prepreg structure, comprising: a mandrel having a contoured surface on which a prepreg ply may be placed;a forming head configured to sweep the prepreg ply onto a first portion of the contoured surface of the mandrel, wherein the forming head includes a tube h

1. An apparatus for forming a composite prepreg structure, comprising: a mandrel having a contoured surface on which a prepreg ply may be placed;a forming head configured to sweep the prepreg ply onto a first portion of the contoured surface of the mandrel, wherein the forming head includes a tube having a plurality of slots therein, and a plurality of fingers defined between the slots, wherein the fingers are configured to slidably engage and press the prepreg ply against the first portion of the contoured surface of the mandrel; anda flexible diaphragm covering the prepreg ply and configured to vacuum form the prepreg ply onto a second portion of contoured surface of the mandrel. 2. The apparatus of claim 1, wherein the fingers are flexible and include fingertips for individually engaging the prepreg ply. 3. The apparatus of claim 1, wherein: the forming head further includes a ram for displacing the forming head. 4. The apparatus of claim 3, wherein the mandrel is elongate and the tube extends along substantially the entire length of the mandrel and includes compliance for conforming the tube to the contoured surface of the mandrel. 5. The apparatus of claim 3, further comprising: a plurality of the forming heads, each of the heads being configured to sweep the prepreg ply, andwherein the tube is held on the forming heads. 6. The apparatus of claim 1, wherein the forming head further includes a device for spreading the fingers. 7. The apparatus of claim 6, wherein the device for spreading the fingers is a plate adjustably mounted on the forming head and contacting the fingers. 8. The apparatus of claim 6, wherein the device for spreading the fingers is an inflatable bladder. 9. The apparatus of claim 1, wherein the head includes a cam mechanism coupled with the fingers for controlling operation of the fingers. 10. The apparatus of claim 1, wherein the plurality of fingers includes: opposed flexible fingers each having a fingertip, anda forming element on each of the fingertips for engaging the flexible diaphragm covering the prepreg ply and forcing the prepreg ply to conform to the mandrel. 11. The apparatus of claim 1, wherein the diaphragm is sealed around its periphery and forms a chamber capable of being evacuated. 12. The apparatus of claim 1, wherein the diaphragm is a flexible vacuum bag surrounding the prepreg ply and is capable of being evacuated. 13. The apparatus of claim 1, wherein the forming head includes a device for securing a portion of the prepreg ply against a section of the mandrel. 14. An apparatus for forming a contoured composite laminate stringer having a hat cross-section and a pair of flanges, comprising: a contoured elongate mandrel on which at least one composite prepreg ply may be placed, the mandrel having a cap section, a pair of web sections and a pair of flange sections; anda plurality of former modules, each of the former modules including a forming head, wherein each of the forming heads includes a tube having a plurality of slots therein and forming fingers located between the slots configured to secure and sweep the prepreg ply onto the cap and web sections of the mandrel. 15. The apparatus of claim 14, further comprising: a flexible diaphragm configured to be sealed around its periphery for vacuum forming the prepreg ply against the flange sections of the mandrel. 16. The apparatus of claim 15, wherein the flexible diaphragm comprises latex stretchable substantially only in one direction. 17. The apparatus of claim 15, wherein the tubes are linked together. 18. The apparatus of claim 15, wherein the tube extends along substantially the entire length of the contoured elongate mandrel and is held by the forming heads. 19. The apparatus of claim 14, wherein the fingers are flexible and are arranged in opposing sets of fingers. 20. The apparatus of claim 19, wherein each of the forming heads includes a mechanism for adjusting a distance between the opposing sets of fingers. 21. The apparatus of claim 14, wherein each of the former modules has an orientation that is adjustable. 22. The apparatus of claim 14, further comprising: at least one mechanism for aligning the forming head with local sections of the mandrel. 23. The apparatus of claim 14, further comprising: mechanisms for adjusting roll, pitch and yaw of the forming head. 24. The apparatus of claim 14, further comprising: at least one support beam, andwherein each of the former modules is mounted on the support beam. 25. The apparatus of claim 24, including a mechanism for adjusting a position of each of the former modules on the support beam. 26. The apparatus of claim 14, further comprising a drive for driving the forming fingers to sweep the prepreg ply onto the flange sections of the mandrel. 27. The apparatus of claim 26, wherein the drive includes a pneumatic cylinder for displacing the forming fingers. 28. The apparatus of claim 26, wherein the drive includes a flexible diaphragm configured to be sealed around its periphery for displacing the forming fingers. 29. The apparatus of claim 14, wherein: each of the former modules includes a frame, andthe mandrel is mounted on the frame of each of the former modules. 30. The apparatus of claim 14, further comprising: a plurality of mobile carts, andeach of the former modules is mounted on one of the mobile carts. 31. The apparatus of claim 14, further comprising: a plurality of mobile carts on which the mandrel may be removably mounted; anda forming station having each of the former modules mounted thereon and adapted to receive mobile carts. 32. An apparatus for forming a contoured composite prepreg laminate, comprising: a contoured mandrel on which at least one composite prepreg ply may be formed;a plurality of former modules arranged side-by-side for respectively forming the prepreg ply on the mandrel, each of the former modules including a forming head associated with a section of the mandrel for forming the prepreg ply on the associated section of the mandrel, wherein each forming head includes a tube having a plurality of slots therein, and a plurality of fingers defined between the slots, wherein the fingers are configured to slidably engage and press the prepreg ply against the first portion of the contoured surface of the mandrel; anda mechanism for aligning each of the forming heads with the contour of the associated section of the mandrel. 33. The apparatus of claim 32, wherein the mechanism is capable of adjusting roll, pitch and yaw of the forming head. 34. The apparatus of claim 32, wherein: each of the former modules includes a frame having a forming head mounted thereon, andthe mechanism includes slides for adjusting alignment of the frame.