JPH06155643A - Panel edge closure material - Google Patents

Abstract

PURPOSE: To enable the mechanical shock protection to damage by covering a peripheral edge and extending a flange part into a core slot from a web part and meshing a closing material with a honeycomb core. CONSTITUTION: A web 40 covers the edges 83, 93 of panel skins 80, 90 to protect them. Further, the meshing arrangement 20 having a projection 21 on the flange 30 of a panel edge closing material 10 is determined corresponding to a core slot 62 so as to obtain close fit at a time of the insertion of the flange 30 into the core slot 62. The core slot 62 has a space predetermined between its upper and lower walls 63, 64 and the width of the flange 30 at the part of the projection 21 is made larger than the space predetermined between the walls of the core slot 62.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a honeycomb panel, and more particularly to an arrangement for closing the edges of a honeycomb panel using a graphite skin.

[0002]

Panels, such as floor panels used in aircraft, were manufactured from panel skins having a honeycomb core material between them. Both graphite and glass panel skins have been used for these types of honeycomb panels. In a panel of the above type, the panel skin has a peripheral edge with the periphery of the honeycomb core located between the peripheral edges of the panel skin. 1 When using honeycomb panels, especially for aircraft flooring
One potential drawback was the inability of the edges of the various layers to be coplanar with each other. further,
The edges need to be protected because it is more certain that the edges will be damaged by the impact compared to the rest of the panel. Such damage can occur during installation, handling and adjustment. The panels can also be damaged when they are removed during aircraft maintenance.
After the panels are attached, their edges may also have a slight gap between them. Thus, this leaves a vulnerable area that is generally exposed to impact. To solve the above problems, it is known to close the edges of the panel, which protects the edges, lays the edges of the panel flush with each other, and strengthens and supports the edges to reduce their vulnerability to scratches. Was there. The current method of closing the edges of the panel is to mechanically remove the depth of one to two cells of the honeycomb core near the entire perimeter of the panel, and then apply a syntactic resin to the next open core area. Including filling with. After the syntactic resin cures, the edges are either machined or sanded by hand and smoothed and flush with the edges of the panel. However, while this type of panel edge closure is expensive and time consuming, it is still practiced on almost all aircraft honeycomb core panels unless the aircraft honeycomb core panel fits into a groove or other edge cover. ing. Moreover, when the honeycomb panels use graphite panel skins, their edges tend to undergo galvanic corrosion upon contact with metal. This can cause problems when, for example, the graphite skin edges of honeycomb panels are used as floor panels in vehicles, such as airplanes, and are attached to aluminum sheet tracks.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved method of closing the edges of honeycomb panels. More specifically, the object of the present invention is to provide an important means of mechanical shock protection against damage, to strengthen the panel edges and to provide a physical separation between the panel members and any adjacent or joining members. To provide an arrangement and method for closing the edges of a honeycomb panel. Furthermore, a special object of the invention is to provide an arrangement and method for separating the edges of the graphite panel skin in a honeycomb panel from any adjacent metal members so as to avoid the occurrence of galvanic corrosion.

[0004]

The above object of the present invention is to provide a honeycomb core between first and second skins having first and second panel skins having a peripheral edge and a peripheral core slot, respectively. And a web portion extending between peripheral edges of the first and second panel skins and covering the peripheral edges, and a flange portion extending from the web portion into the peripheral core slot of the honeycomb core. This is accomplished by providing a panel edge closure arrangement comprising a closure having The flange portion has a meshing arrangement on which the honeycomb core is meshed.

Furthermore, it is preferred that the closure is made of a non-conductive material, especially when the panel skin is made of graphite. The non-conductive material is preferably an extrudable resin. Further, the resin is preferably acrylic resin, ABS, polystyrene, polyethylene, P
The material selected from the group consisting of VC, polycarbonate, acetate, butyrate, propionate, polyurethane and thermosetting materials. Of the above materials, polyurethane is preferred. In accordance with another preferred aspect of the present invention, adhesive may be provided to the surrounding core slots to bond the closures at the surrounding core slots. The adhesive is preferably a syntactic resin, which consists of glass or phenolic resin microballoons, an epoxy resin and a curing agent. The syntactic resin may also consist of polyester resin and glass or phenolic resin microballoons. The first and second panel skins may also be resin impregnated fabric skins. In this case, the purpose of the closure is, as mentioned above, mainly to protect the edges and corners of the laminated skin from damage. The peripheral core slots in the honeycomb core have opposing walls that bound the peripheral core slots therebetween. The opposing walls are spaced apart by a predetermined amount, and the mating arrangement engages at least one of the opposing walls with an interference fit. That is, the flanges are presented at the position of the interlocking arrangement to be wider than the predetermined amount that the opposing walls are spaced apart. The mating members are preferably projections that equally project from both sides of the flange. Also preferably, the flange has a tapered front end that slopes outwardly and rearwardly toward the web to the point of the flange that delimits the protrusion. Further, the flange may have a protrusion on only one side and the other side may be flat and have no protrusion. The flanges may have at least one protrusion on each of their opposing sides that mates with each other by an interference fit. In addition, the flanges also interlock with opposing walls of the core slot with an interference fit,
It may have two such protrusions on each of its opposite sides. The web also provided with two separate flanges for the two separate core slots for use in a sandwich panel with two separate honeycomb cores to be glued together as a double honeycomb core sandwich panel. Good.

The above object of the present invention is further achieved by providing a method of closing the edges of a panel having two panel skins having peripheral edges and a honeycomb core therebetween. The method includes first providing a closure having a web portion and a flange portion extending from the web portion. The flange portion has a mating arrangement thereon. The peripheral core slots are then cut in the honeycomb core and the flange portions are inserted into the peripheral core slots to engage the mating members with the honeycomb core by an interference fit and cover the peripheral edges of the panel skin with the web portion. The method according to the invention further comprises the step of supplying an adhesive to the surrounding core slot prior to inserting the flange portion so as to couple the flange location to the surrounding core slot.

[0007]

Other objects, aspects and advantages of the present invention include:
It will be apparent to those skilled in the art from the following detailed description of the preferred embodiments of the invention when taken in conjunction with the accompanying drawings. A first embodiment of the invention is shown in FIGS. FIG. 1 shows a panel edge closure 10, and FIG. 2 shows a panel edge closure 10 mated with a honeycomb panel structure 50. Panel edge closure 1
0 includes a web 40 that acts as an edge shield to shield the edges of the panel skin of the honeycomb panel. Flange 30 is integral with web 40 and extends from one side thereof. Flange 30 has a distal end 33 that is inserted into the honeycomb panel. Flange 30
Also has an interlocking arrangement 20 on one side thereof, the interlocking arrangement comprising a projection 21 projecting from one side of the flange 30. The panel edge closing material 10 is made of acrylic resin, ABS, polystyrene, polyethylene, PVC,
It may be manufactured from polycarbonate, acetate, butyrate, propionate, polyurethane or thermosetting materials such as phenolic resins, melamine resins, epoxy resins and glass-reinforced materials. However, polyurethanes are generally preferred because they have good resistance to most liquids and solvents and are formulated to be self-extinguishing. In addition, polyurethane meets FAA performance requirements for flame retardancy in aircraft interiors. However, thermoset materials, such as those pultruded out of glass and phenolic resins, are particularly preferred in applications requiring nonflammable materials. Further possible extruded materials include polyetherimides, polysulfones, polyethersulfones, polyphenylsulfones and polycarbonates.

As shown in FIG. 2, the honeycomb panel 5
0 is the first panel skin 80 and the second panel skin 90
And the first panel skin 80 and the second panel skin 9
The honeycomb core 60 is sandwiched between 0 and 0. The first and second panel skins have first and second edges 83.
And 93, the edges being aligned with each other.
The honeycomb core 60 may be Nomex or glass. First and second panel skin 80
And 90 may be reinforced laminates such as glass or graphite / phenolic resin or epoxy resin panel skins. Honeycomb panel 50 is generally similar to the honeycomb panel described in commonly distributed US Pat. No. 4,956,217, which is incorporated herein by reference. According to the present invention, the honeycomb core 60
There is a core slot 62 around the perimeter of the honeycomb that extends along a perimeter parallel to the panel skins 80 and 90 and that opens to the peripheral edge of the honeycomb panel 50.
The core slot 62 has upper and lower walls 63 and 64. The flange 30 of the panel edge closure 10 is inserted into the core slot 62 and is provided with a projection 21 that fits into one of the upper and lower walls 63 and 64 by an interference fit to provide the panel edge closure 10 to the peripheral edge of the honeycomb panel 50. Hold. The dimensions of the panel edge closure 10 are determined so that the web 40 covers and protects the edges 83 and 93 of the panel skins 80 and 90, as shown in FIG. Further, the dimensions of the mating arrangement 20 with the protrusions 21 on the flanges 30 of the panel edge closure 10 depend on the core slots 62 so that an interference fit is obtained when the flanges 30 are inserted into the cores 62. It is determined. That is, the core slot 62
Has a predetermined space between the upper and lower walls 63 and 64, and the width of the flange 30 in the portion of the protrusion 21 is selected to be wider than the predetermined space between the walls of the core slot 62. To be done. In accordance with any aspect of the present invention, the syntactic foam adhesive 70 comprises a flange 3
It is supplied to the core slot 62 before the insertion of 0. Once the flange 30 is inserted into the core slot 62, the syntactic adhesive 70 is transferred around the flange 30 and into the adjacent core cells of the honeycomb core 60. Once the adhesive has hardened, an intermeshing mechanical bond with the protrusions 21 is formed to help retain the protrusions 21 within the core slots 62. The syntactic adhesive 70 also provides for the first and second panel edges 83 and 9 during flexing and impact.
It may help to increase the mechanical strength of 3. Syntactic adhesives are dense and non-flowing, which can cause spillage,
It is noted that gravity has a lower tendency to stay on the lower panel skin 80 as compared to liquid adhesives. Preferred syntactic adhesives include syntactic resins consisting of glass microballoons, epoxy resins and hardeners. Polyester or epoxy resins may be used with phenolic resin microballoons if non-flammability requirements are not required. It should be emphasized that the syntactic resin 70 is optional. The interference fit of the protrusions 21 may be sufficient to secure the panel edge closure 10 in place.

The panel edge closing member according to the present invention is formed as follows. First, the honeycomb panel 50 has a panel skin 8 of glass-graphite / epoxy resin or glass-graphite / phenol resin panel skin.
Nomex or glass honeycomb core 60 between 0 and 90 is laminated using an epoxy adhesive film for assembling the honeycomb panel 50. The panel assembly is cured at 50 psi and 260 ° F for 1 hour. Then on the edge around the cured panel,
A tool with a centering guide and a saw blade is used to make an elongated depression in the desired depth and width of slot 62. After indenting to the correct depth, the pneumatic seal gun 91 is loaded with syntactic foam 70, as shown in FIG. The seal gun 91 is equipped with a tip 92 that can fit into the core slot 62. The syntactic foam 70 is then injected into the slot 62 so that the foam fills the core slot 62. The panel edge closure 10, which is formed as an extrudate, is then mated, for example, in place within the slot 62 and the web 40 is pressed to be flush with the edges 83 and 93. Protrusion 2
The interlocking arrangement with 1 is fully inserted into core slot 62 and syntactic foam 70. By pushing the flange 30 into the core slot 62, the syntactic foam 70 is transferred into adjacent core cells above and below the core slot 62. The flange 30 is then surrounded by a syntactic foam 70, integrating the syntactic foam, the honeycomb core 60 and the panel edge closure 10. The assembly is left to cure at room temperature for 8-10 hours, after which an interlocking mechanical bond holding the interlocking arrangement 20 is formed.

As shown in FIG. 8, the honeycomb panel 5
The zero corner can be bent by the panel edge closure 10 by simply cutting a notch, for example, a notch with two 47-50 cuts through the flange 30 but not the web 40. The web 40 can then be bent around the corners as shown in FIG. After bending, the corners may be heated for a short time to stress release the web.

Also, as shown in FIG. 9, other edge shapes may be formed by the panel edge closure 10. In the embodiment shown in FIG. 9, an annular hole is formed in the honeycomb panel 50 and a flange 30 cut at multiple locations is provided to allow the web 40 to be bent annularly as shown. By having a panel edge closure, it closes the peripheral edges inside the honeycomb panel 50.

As described above, the adhesive 70 is used to bond the panel edge closure 10 to the peripheral edges of the honeycomb panel 50 and the core slots 62. However, it is not necessary to use an adhesive. The core slot 62 may be machined small enough so that the interference press fit of the protrusions 21 of the mating arrangement 20 will remain in place within the core slot 62 without adhesive. For example, the width of the flange 30 at the portion of the protrusion 21 may be 0.104 "and the core slot may then be about 0.060" wide. However,
Generally, the core slot 62 is machined to 0.010 "to 0.030" which is narrower than the minimum width of the flange 30 at the portion of the mating arrangement 20. In one example, the core slot is 0.090 "+/- 0. Machined to a width of 0.005 "and the extrudate has a width of 0.104" +/- 0.002 ". This gives a minimum of 0.007" and a maximum of 0.0.
A 21 "interference fit is obtained. Generally, the core slot 6
2 should be at least 0.04 "deeper than the length of the flange 30. Thus, an important dimension of the panel edge closure 10 of the present invention is the protrusion 21 portion of the flange 30 relative to the width of the core slot 62. There must be sufficient interference fit to hold the panel edge closure 10 in place while the syntactic adhesive 70 cures, with a minimum of 0.0 from the protrusion 21 to the adjacent wall of the flange 30.
2 "is present, and preferably the flange 30 has a minimum thickness of 0.050". These preferred dimensions are primarily related only to the need to extrude the panel edge closure 10 and to the proper flow of material during closure manufacture, and not to the performance of the panel edge closure 10. .

3-6 show another embodiment of the present invention. Although they have different shapes, they are operated in the same manner in principle as the above. Moreover, features similar to those shown in FIGS. 1 and 2 are labeled with the same reference numbers in FIGS. 3-6. 3 and 4 show a second embodiment according to the present invention. The main difference in this embodiment is that the panel edge closure 110 engages two protrusions 21 and 22 extending from opposite sides thereof to engage both the lower and upper walls 63 and 64 of the core slot 62. Having an arrangement 20. The distal end 33 of the flange 30 tapers outwardly and rearwardly therefrom toward the protrusions 21 and 22. FIG. 4 shows the panel edge closure 110 in place within the honeycomb panel 50. 5 and 6 show four projections 21, 22, 23 and 2 in the mating arrangement 20 for further mating with the lower and upper walls 63 and 64 of the honeycomb panel 50.
4 shows a panel edge closure 210 using 4. A protrusion for retaining the panel edge closure in the core slot 62,
Instead of using, for example, the protrusion 21, a groove may be provided in the core slot 62 that mates with the hardened syntactic adhesive 70 to retain the panel edge closure.

10 and 11 show a single web 40 for use in a double honeycomb sandwich panel 50.
3 shows a panel edge closure 310 with two flanges 30 extending from it. Each flange 30 has a mating arrangement 20 thereon, which comprises a protrusion 21 that slopes toward the distal end 33 as shown. The main difference between this fourth embodiment of the invention and the other above embodiments is that this embodiment is used in a double honeycomb sandwich panel 50 as shown in FIG. In this honeycomb panel 50, two separate honeycomb cores 60a and 60b have a partition wall 61 between them.
It is used in the form of being laminated by being sandwiched and bonded together. The panel edge closure 310 is used similarly to the edge closure of the previous embodiment, but for the two core slots 62 in each honeycomb core 60a and 60b. In addition to achieving the above effects, the panel edge closure 310 also includes two honeycomb cores 6.
It may help to secure 0a and 60b together.
In one example of this fourth embodiment, the web 40 is 1 "from top to bottom as shown in the figure and is 0.060" thick. The flange is also 0.6
0 "and 0.17 from each end of web 40
0 "apart. The mating arrangement 20 projects about 0.60" from its flange 30 and is about 0.420 "apart. The mating arrangement 20 further extends from the projection 21 to the distal end 33. , Extends about 0.25 "along the end of flange 30. The material may be opaque brown or natural color ULTEM 9065.

As explained above, the present invention provides a simple, low cost closure system, and facilitates honeycomb panels to strengthen and protect the edges of the panel and prevent galvanic corrosion. , And a panel edge closure arrangement that can be safely formed and a method of forming the arrangement can be provided. Various modifications of the above panel edge closure arrangements and methods will occur to those skilled in the art without departing from the scope of the invention as defined by the following claims, which are present in the present invention. Should be considered part of the invention.

[Brief description of drawings]

1 is a cross-sectional view of a panel edge closure according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a honeycomb panel using the panel edge closing material shown in FIG.

FIG. 3 is a cross sectional view of a panel edge closure according to a second embodiment of the present invention.

[Fig. 4] Fig. 4 is a cross-sectional view of a honeycomb panel using the panel edge closing member shown in Fig. 3.

FIG. 5 is a cross sectional view of a panel edge closure according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a honeycomb panel using the panel edge closing material shown in FIG.

FIG. 7 is a perspective view of a honeycomb panel having a peripheral core slot to which an adhesive has been applied.

FIG. 8 is a partial plan view of a panel edge closure according to the present invention using closed slot geometry to create 90 ° bends for low residual stress 90 ° bends.

FIG. 9 is a partial plan view of a honeycomb panel using a panel edge closure according to the present invention to close an annular edge of a hole in the panel.

FIG. 10 is a cross sectional view of a panel edge closure according to a fourth embodiment of the present invention.

11 is a cross-sectional view of a honeycomb panel using the panel edge closing material shown in FIG.

[Explanation of symbols]

 10, 110, 210, 310 Closing material 20 Engaging means 30 Flange 40 Web 50 Honeycomb panel 60 Honeycomb core 62 Honeycomb core slot 80, 90 Panel skin 83, 93 Panel edge

Claims (21)

[Claims] 1. A first and a second panel skin each having a peripheral edge; having a peripheral core slot,
A honeycomb core between the first and second skins; and a closure having a web portion, a flange portion and a meshing means, wherein the web portion is between the peripheral edges of the first and second panel skins. And covers the peripheral edge, the flange portion extends from the web portion into the peripheral core slot of the honeycomb core, and the engaging means engages the closure with the honeycomb core. Panel edge closure arrangement made of material. 2. The panel edge closure arrangement of claim 1, wherein the panel skin is graphite and the closure is made of a non-conductive material. 3. The panel edge closure arrangement according to claim 2, wherein the electrically non-conductive material is an extrudable resin. 4. The extrudable resin is acrylic resin, A
BS, polystyrene, polyethylene, PVC, polycarbonate, acetate, butyrate, propionate,
The panel edge closure arrangement according to claim 3, wherein the panel edge closure arrangement is a material selected from the group consisting of polyurethane and thermosetting materials. 5. The panel edge closure arrangement of claim 3 wherein the extrudable resin is polyurethane. 6. The panel edge closure arrangement of claim 1, wherein the mating means further comprises an adhesive in the peripheral core slot that bonds the closure at the peripheral core slot. 7. The panel edge closure arrangement according to claim 6, wherein the adhesive comprises a syntactic resin. 8. The panel edge closed arrangement according to claim 7, wherein the syntactic resin comprises glass microballoons, an epoxy resin and a curing agent. 9. The panel edge closed arrangement according to claim 7, wherein the syntactic resin comprises an epoxy or polyester resin and a phenolic resin microballoon. 10. The panel edge closure arrangement of claim 1, wherein the first and second panel skins are glass skins. 11. The peripheral core slots in the honeycomb core have opposing walls defining the peripheral core slots therebetween; the opposing walls being spaced apart by a predetermined amount; and The panel edge closure arrangement of claim 1, wherein the interlocking means engages the flange with at least one of the opposing walls by an interference fit. 12. The panel edge closure arrangement according to claim 11, wherein said flange is wider at the position of said interlocking means compared to a predetermined amount by which said opposing walls are spaced apart. 13. The panel edge closure arrangement according to claim 11, wherein said interlocking means comprises a protrusion protruding from one side of said flange. 14. The flange faces the web,
14. The panel edge closure arrangement of claim 13 having a tapered front end sloping outward and rearward to the point of the flange defining the protrusion. 15. The panel edge closure arrangement of claim 13 wherein said flanges have at least one said protrusion on each of its opposing sides that engages each of said opposing walls by an interference fit. 16. The panel edge closure arrangement according to claim 15, wherein said flange has two said projections on each of its opposite sides which engage said opposed walls by an interference fit. 17. A method of closing an edge of a panel having two panel skins having a peripheral edge and a honey-comb core in between, the following steps: a web portion and extending from the web portion and above the web portion. And a flange portion having a protrusion on the honeycomb core; cutting a peripheral core slot in the honeycomb core; and inserting the flange portion into the peripheral core slot, and tightening the honeycomb core with the protrusion. Mating by fitting, and covering the peripheral edge of the panel skin with the web portion. 18. The method of claim 17, further comprising the step of applying an adhesive to the peripheral core slot prior to inserting the flange portion. 19. Between the first and second skins,
A second honeycomb core having a second peripheral core slot; a partition between the first honeycomb core and the second honeycomb core; and the web of the closure to the second peripheral core. The panel edge closure arrangement of claim 1 further comprising a second flange portion extending into the slot and having second interlocking means for interlocking the closure with the second honeycomb core. 20. The non-conductive material is phenol resin,
A panel edge closure arrangement according to claim 2 which is a thermosetting material selected from the group consisting of melamine resins, epoxy resins and glass reinforced materials. 21. The panel edge closure arrangement of claim 20, wherein the thermosetting material is pultruded from glass and phenolic resin.