COMPOSITE STRUCTURES WINDOW BELT AND METHOD OF MAKING

Abstract: A composite structure window belt (10) has a row of lined, reinforced, diamond-shaped window frames (12) set between honeycomb core sections (14) and covered top and bottom with reinforced plastic covers (16) and (18). The window frames (12) have build-in reinforcements (60) to accept fasteners (74) for securing windows (66) within diamond-shaped openings of the window frames (12).

Description: COMPOSITE STRUCTURES WINDOW BELT AND METHOD OF MAKING BACKGROUND OF THE INVENTION The use of reinforced plastics in composite structures has been increasing rapidly in the aircraft industry due to the high strength to weight ratio of the composite. The composites often must be tied by mechanical fasteners in order to transfer loads from the composite to metallic structures. These fasteners weaken the structure and add weight and increase manu¬ facturing costs. It was found that a composite structure window belt could be made that has all but eliminated the need for fasteners. SUMMARY OF THE INVENTION Reinforced plastic window frames have an es¬ sentially diamond-shaped window opening. The window frame has a flange extending into the opening adjacent the outside of the window and an outwardly extending flange having a series of reinforcements for receiving glass retainers adjacent the inside of the window. The window frames are placed in a line with honeycomb core between and around the frames. A reinforced plastic covering is placed above and below the window frames and the core material and cured into a composite structure window belt. OMPI ■ V - WlJrO DESCRIPTION OF THE DRAWINGS Figure 1 shows a fragmented plan view of a window belt of this invention. Figure 2 shows a section taken along line 2-2 of Figure 1. Figure 3 shows an exploded perspective view of the window frame shown as part of Figure 1. Figure 4 shows a perspective view of the window frame of Figure 1 with the parts joined together, mounted on a mandrel, and filaments being wound around the frame. Figure 5 shows a fragmented perspective view of a section of the window frame with fibers wound around it as in Figure 4. Figure 6 shows a similar fragmented perspective view of a section of the window frame with an additional reinforcement with fibers wound around it. Figure 7 shows a cross section taken along the line 7-7 of Figure 8. Figure 8 shows a cross section taken along the line 8-8 of Figure 1. Figure 9 shows a cross section with window taken along the line 9-9 of Figure 1. Figure 10 shows a perspective view showing the window belt being formed and cured. Figure 11 shows a plan view of a section of window belt with a different embodiment for the window frame. Figure 12 shows a cross section taken along the line 12-12 of Figure 11. Figure 13 shows a cross section taken along the line 13-13 of Figure 11. DETATLED DESCRIPTION A composite structure window belt 10 is made up of a series of reinforced plastic window frames 12, honey¬ comb core material 14, an inner reinforced plastic cover 16 and an outer reinforced plastic cover 18. Each window frame, as is best shown in Figures 3 through 9, is made up of molded reinforced plastic parts 20, 22, 24 and 26. These parts are molded from any of the known reinforced plastics with graphite filaments and epoxy resin the pre- ferred combination. The ends of the parts are formed to mate with each other. See Figures 7 and 8 where over¬ lapping enlargement 28, part 26, mates with end 30 of part 20. This meeting is typical of all the ends of the parts. The parts are mated together, secured on mandrel 32 with fasteners 34, the mandrel rotated and a graphite filament 36 wound around the outer periphery of the window frame and built up into a reinforcing film 38. The fila¬ ment is distributed from a dispenser 40 mounted to move back and forth on a monorail 42. The filament may have a coating of resin, or a resin may be applied to the built-up film. The parts when combined have a diamond- shaped window opening 44. All of the parts have a flange 46 that is tapered inwardly toward the window opening, and all have a pair of legs 48 and 50 that extend outward in a U shape. These legs have recesses 52 and 54 that are sized to accept and mate with ends of a cover plate 56. That cover plate is placed into the ends of the U-shaped legs and a layer of reinforcing filaments 58 in a resin is laid up on the outer surface. On the leg 50, which is furthest from the inwardly directed flange 46, there are a series of reinforcements 60. The formed window frames 12 are spaced apart and placed in a line. Honeycomb core 14 is placed between and around the window frames. This honeycomb may be pre- pared from any of the known honeycomb materials, with a nonmetallic material preferred. A reinforced plastic outer OMPI - cover 18 and inner cover 16 enclose the window frames 12 and the core material 14 and the lay-up is cured into the composite structure window belt. These covers may be pre¬ pared from any of the known reinforced plastics, with graphite filaments impregnated with an epoxy resin pre¬ ferred. Alter the window belt is formed, the inner reinforced plastic cover is cut away on each window frame along the line 62, and the outer reinforced plastic cover is cut away along the line 64 to expose the window opening. However, it is preferred to wait until after the window belt is installed into a composite structure with a cover¬ ing fiber reinforced inner layer 63 and fiber reinforced outerlayer 65, as in Figure 9, and all the layers cut away at 62 and 64 at the same time. Figure 9 shows a typical window mounting in the window frame with window panes 66 and 68 held in spaced relation to each other with a shaped resilient insert 70. The insert is located.to position the outer surface 72 of window pane 66 to follow the contour of the outer surface of the reinforcing cover 65. The window panes and the insert are held in position by a formed clip 72 that is secured to the window frames with a series of fasteners 74 that screw into the rein¬ forcements 60 in the window frame. A spring clip 76 snaps over projection 78 of the formed clip and positions and holds a transparent sheet 80 in the window opening. Figures 11 through 13 show a different embodi¬ ment of a window frame 12A for making up a composite structure window belt. In this window frame the frame is formed in one piece. This frame has an essentially diamond-shaped opening and has a modified Z-shaped cross- section with flange 82 extending inward into the window opening at the outer side of the frame and an outwardly extending flange 84 at the inner side of the frame. A series of reinforcements 86 on the under side of the outwardly extending flange are used to accept a fastener for mounting a window to the window frame. The cross OI Π section of the frame is thickened at top and bottom 88 to add strength. To make up the window belt when using this embodiment, inner reinforcing plastic cover 16A and outer reinforced plastic cover 18A extend over core 14A and the window frames. Figure 10 shows a preferred method of forming a window belt by passing the lay-up through a microwave curing applicator 90 which has a set of internal dies 92. First, a layer of graphite filaments impregnated with an epoxy resin is laid down. Formed window frames 12 are then laid up and surrounded with nonmetallic honeycomb core 14. A layer of graphite filaments impregnated with an epoxy resin is laid over the core with frames and advanced through the microwave applicator to cure the lay-up and continuously form a composite structure window belt. OYxTl

Claims: I claim: 1. A window containing section of a composite structure for fuselage comprising: a row of spaced-apart reinforced plastic window frames, means on the window frames for securing windows within the frames, a layer of reinforcing filaments coated with a resin wound around a periphery of each window frame, a core of honeycomb ex¬ tending between window frames, a reinforcing filament wound resin impregnated inner shell, and a reinforcing filament wound resin impregnated outer shell to make up a shaped composite structural section. 2, A window containing section of a composite structure as in claim 1 wherein the window frames are in sections to be joined by the filaments encircling the periphery. 3. A window containing section of a composite structure as in claim 2, further comprising: the window frames having laterally outwardly extending U-shaped legs, a reinforced plastic cover to mate with the ends of the legs, and a layer of reinforcing filaments coated with a resin wound around the periphery of the mating plastic cover. 4. A window containing section of a composite structure as in claim 1 wherein the window frames are each of a one-piece, essentially Z-shaped construction. 5. An elongated section of a composite structure containing windows, with the structure com¬ prising: a series of spaced-apart, essentially diamond- shaped window frames each made up of parts of reinforced 5 plastic, mating connections where the parts join, laterally outward extending U-shaped legs, a tapered flange to extend laterally inward, a layer of reinforcing filaments coated with a resin wound around the outer periphery of the joined parts, a series of reinforcing enlargements to accept a •10. fastener for retaining a window in the frame with the en¬ largements located along the inner side of the leg that is furthest from the flange, a cover plate of reinforced plastic to extend between the ends of the legs, and a layer of reinforcing filaments coated with a resin wound 15 around the outside of the cover plate; a honeycomb core to extend between and around the window frames; a rein¬ forcing filament wound resin impregnated inner shell; and a reinforcing filament wound resin impregnated outer shell with all the components making up an elongated section of 20 a composite structure containing spaced-apart windows. 6, An elongated section of a composite structure containing windows, with the structure comprising: a series of spaced-apart, essentially diamond-shaped window frames each made up of reinforced plastic and having a modified 5 Z-shaped cross section; a series of reinforcing enlarge¬ ments to accept a fastener for joining a window to the frame with the enlargement located along the inner side of an outer leg of the modified Z-shape; a honeycomb core to extend between and around the window frames? a. rein- 0 forcing filament wound resin impregnated inner shell; and a reinforcing filament wound resin impregnated outer shell with the components making up an elongated section of a composite structure containing windows. 7. An elongated section of a composite structure containing windows as in claim 6, further com¬ prising: a layer of reinforcing filaments coated with a resin wound around the outer side of each window frame. 8. A method of preparing an elongated section of a composite structure window belt, with steps com¬ prising: preparing fiber reinforced plastics for a window frame with an essentially diamond-shaped opening, 5 extending a tapered flange into the opening adjacent the outside of the window frame, extending a flange away from the opening adjacent the inside of the window frame and providing reinforcements along the flange for fastening a window to the frame, winding a reinforcing filament into •10 a coating impregnated with resin around the back side of the window frame, placing the window frame in a spaced- apart line, locating honeycomb core in the area between and around the window frames, covering the window frames and the core with an inner layer and an outer layer of 5 reinforcing filaments impregnated with a resin, and curing into a composite structure. 9. A method of preparing an elongated section of a composite structure as in claim 8 with the further step of winding a reinforcing filament into a coating impreg¬ nated with resin around the back side of each window frame. 10. A method of preparing an elongated section of a composite structure as in claim 8 with further steps comprising: extending a flange on each window frame away from the opening adjacent the outside of the window frame, preparing each window frame in sections, using matching ends on the sections, winding a reinforcing filament into a coating impregnated with resin around the back side of each window frame, locating a cover plate for extending between the ends of the outwardly extending flanges, and winding a reinforcing filament into a coating impregnated with resin around the outside of the cover plate. 11. A method of preparing an elongated section of a composite structure window belt, with steps com¬ prising: preparing fiber reinforced plastics for a window frame with an essentially diamond-shaped opening, extending a flange into the opening adjacent the outside of the window frame, extending a flange away from the opening adjacent the inside of the window frame and providing reinforcements along the flange for fastening a window to the frame, placing the window frame in a spaced-apart line, locating honeycomb core material around and between the window frames, covering the window frames and core material above and below with a layer of resin impregnated reinforcing filaments, and passing the covered unit through the dies of a microwave curing applicator for curing into a composite structure window belt. 12. A method of preparing an elongated section of a composite structure as in claim 11 with the further step of winding a reinforcing filament into a coating im¬ pregnated with resin around the back side of each window rame. lS. A method of preparing an elongated section of a composite structure as in claim 11 with further steps comprising: extending a flange on each window frame away from the opening adjacent the outside of the window frame, preparing each window frame in sections, using matching ends on the sections, winding a reinforcing filament into a coating impregnated with resin around the back side of each window frame, locating a cover plate for extending between the ends of the outwardly extending flanges, and winding a reinforcing filament into a coating impregnated with resin around the outside of the cover plate.

Inventors: WHITENER PHILIP CHARLES, WHITENER, PHILIP, CHARLES
Applicants: BOEING CO, THE BOEING COMPANY
Application year: 1981
Main classification: B64C1
IPC codes: B64C1