WO2010109311A2

WO2010109311A2 - Frame and fabric panel assembly

Info

Publication number: WO2010109311A2
Application number: PCT/IB2010/000667
Authority: WO
Inventors: Stephanus Bekker; Gustav Johann Van Der Merwe
Original assignee: AAT COMPOSITES Pty Ltd
Current assignee: AAT COMPOSITES Pty Ltd
Priority date: 2009-03-26
Filing date: 2010-03-25
Publication date: 2010-09-30
Anticipated expiration: 2011-09-26
Also published as: WO2010109311A3

Abstract

A frame and fabric panel assembly is provided comprising a fibre reinforced synthetic resin frame (1) to which at least one fabric panel (2) is permanently secured. Appropriate areas of the fabric panel are secured to the frame by at least partially embedding such appropriate areas of the fabric in synthetic resin that is chemically bonded to the synthetic resin of the frame in order to form said permanent bond. A process for the production of the assembly is also provided comprising the steps of applying one or more layers (4) of woven or nonwoven fibre reinforcing material and uncured resin to a prepared mould surface (3) to form an uncured fibre reinforced frame having at least a partially exposed outer surface. The fabric panel is tensioned in a position over spaced appropriate areas of the exposed outer surface and the availability of sufficient uncured resin to at least partially embed said appropriate areas of the fabric panel in uncured resin is ensured. The mould cavity is closed and the resin allowed to cure to permanently secure the appropriate areas of the fabric panel to the frame.

Description

FRAME AND FABRIC PANEL ASSEMBLY

FIELD OF THE INVENTION

This invention relates to a frame and fabric panel assembly in which opposite edges or ends of a fabric panel, that may assume the form of webbing, are permanently secured to opposite frame members of a fibre reinforced resin frame that is typically a component of a seat and backrest assembly.

More particularly, but not exclusively, the invention relates to frame and fabric panel assemblies of the general type in which the frame is a thermoset or thermoplastic composite tubular frame that, for example, may be used in the seat of a transport vehicle, especially an aircraft.

The fabric panel typically provides support for a seated person but may also simply close the space between two opposite frame members.

The invention also relates to a process for the production of a fibre reinforced structure having a fabric panel, especially a pre-tensioned fabric panel, permanently secured to it.

BACKGROUND TO THE INVENTION

A substantial number of manufactured thermoset and thermoplastic composite frames having opposite ends or edges of fabric panels permanently secured to opposite frame members are used in vehicle and aircraft seat assemblies, for example. Such fabric panels typically provide lumbar support for mostly ergonomic reasons to provide comfort to a passenger while seated. The fabric panel also reduces the amount of cushioning required on, for example, a backrest. The permanent securing of the ends or edges of a fabric panel to such a frame in an effective manner is, however, problematic in a production facility. It has become common practice to use an aluminium or composite structure in which loop and pile fastener components such as those sold under the trade name VELCRO™ and grooved slots are used to fasten the fabric panel to the frame. This, however, involves more than one production step and the use of various fasteners thereby adding to the cost of labour as well as of components.

OBJECT OF THE INVENTION

It is an object of this invention to provide a fibre reinforced frame and fabric panel assembly of the general type outlined above in which a pre-tensioned fabric panel is permanently attached to the frame.

It is another object of the invention to provide a process for the production of such assemblies, especially, although not necessarily, in a single production process.

SUMMARY OF THE INVENTION

In accordance with one aspect of this invention there is provided a frame and fabric panel assembly comprising a fibre reinforced synthetic resin frame to which at least one fabric panel is permanently secured, the assembly being characterised in that appropriate areas of the fabric panel are secured to the frame by at least partially embedding such appropriate areas of the fabric in synthetic resin that is chemically bonded to the synthetic resin of the frame in order to form said permanent bond.

Further features of this aspect of the invention provide for the fabric panel to be a dry woven type of material, particularly a type that is often referred to as webbing; for the appropriate areas to be at least a pair of opposite edge or end regions of the fabric panel; for the fabric panel to be under a predetermined tension in the installed condition; for the said appropriate areas to be secured to a surface of the frame by resin that bonds to the resin of the frame with the option that the appropriate areas may be sandwiched between such a surface of the frame and a fibre reinforced overlay covering said appropriate areas; for the fabric panel to be secured to surfaces of the frame that are generally coplanar with the panel in the installed condition in which instance a reinforcing strip may be attached to the fabric panel and to another surface of the frame with the attachment of the reinforcing strip to the fabric panel being by way of stitching or adhesive, or preferably both; for the fibres in the fibre reinforced composite structure to be carbon or glass fibres; for the resin to be either a thermosetting resin or a thermoplastic resin; and for the assembly to be a component of a vehicle seat assembly or an aircraft seat assembly, especially a seat or backrest thereof.

Production of an assembly defined above may be achieved by securing the appropriate areas of a fabric panel to a fibre reinforced synthetic resin frame after the latter has been manufactured.

However, it is preferred that the securing of the appropriate areas of the fabric panel to a fibre reinforced synthetic resin frame be carried out during production of the frame itself.

Thus, in accordance with a second aspect of the invention there is provided a process for the production of a fibre reinforced frame and fabric panel assembly, the process comprising the steps of applying one or more layers of woven or nonwoven fibre reinforcing material and uncured resin to a prepared mould surface to form an uncured fibre reinforced frame having at least a partially exposed outer surface; the process being characterised in that a fabric panel is tensioned in a position over spaced appropriate areas to be attached to the frame that form part of the partially exposed outer surface; ensuring the provision of sufficient uncured resin to at least partially embed said appropriate areas of the fabric panel in uncured resin; closing the mould cavity; causing or allowing the resin to cure to thereby cause the frame to cure whilst permanently securing the appropriate areas of the fabric panel to the frame; and opening the mould and removing the moulded fibre reinforced frame therefrom together with the permanently attached fabric panel.

Further features of this aspect of the invention provide for the frame to be of tubular shape in which instance said one or more layers of fibre reinforcing material and uncured resin are closed to form a tubular configuration around an inflatable bladder; for the mould to be partially closed by clamping top and bottom parts of a mould together to simultaneously clamp the fabric panel to the mould in a tensioned condition, preferably by engaging the fabric panel on the inside of the relevant frame member in which instance excess fabric of the fabric panel can be trimmed away followed by final closing of the mould and inflating of any bladder that may be present preparatory to curing of the resin; for the exact tensioning of the fabric panel to be carried out with the aim of providing optimum comfort and support; for curing to be effected at an elevated temperature; and for additional pressure to be applied either to the internal or external surfaces of the composite lay up.

Still further features of the invention provide for a plurality of different fabric panels to be secured to a frame to span different areas of the frame with each fabric panel optionally being differently tensioned; for the fibre reinforcing material and uncured resin to be in the form of sheets of fabric reinforcing made of reinforcing fibres that are pre-impregnated with the necessary resin, typically epoxy or phenolic resin, that is sufficient to form the fibre reinforced composite simply by heating whilst applying pressure; and for the fabric panels to be positioned and fixed in such a way as to prevent resin from reaching specific areas of the fabric panel. The order that the invention may be more fully understood one embodiment thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:-

Figure 1 illustrates schematically an example of a fibre reinforced composite frame such as is used as an airline seat backrest, the frame having a plurality of fabric panels permanently secured to it;

Figure 2 illustrates schematically an open mould with the exposed mould surfaces;

Figure 3 illustrates schematically the assembly of the mould sides to completely enclose the fibre reinforced matrix after fibre placement and prior to pressurisation;

Figure 4 illustrates schematically the assembled mould;

Figure 5 is a schematic section taken through one alternative in which the fabric panel is simply secured on top of one of the surfaces of the tubular composite frame.

Figure 6 is the same as Figure 5 but showing additional layers of woven or nonwoven fibre reinforcing material placed as an overlay on top of the edge of the fabric panel to sandwich it between the overlay and appropriate areas of the tubular frame as well as an optional reinforcing strip; Figure 7 illustrates schematically the initial step in the production of an assembly such as is illustrated in Figure 6;

Figure 8 illustrates, in lesser detail, an intermediate step in the production of the assembly illustrated in Figure 6; and,

Figure 9 illustrates the final step in which the mould is finally closed and without specifically illustrating the reinforcing strip.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

In one embodiment of the invention a typical inverted U-shaped tubular fibre reinforced article in the form of a tubular composite frame (1), illustrated in Figure 1 , is made using the preferred method of the invention, the frame being that of a backrest of an aircraft or other transport vehicle seat. Such a tubular frame generally follows an ergonomic contour, insofar as its general plane is concerned, and may vary along its length in its cross-sectional size and shape according to well-developed designs. However, for the purposes of simplicity in describing the present invention, the cross-sectional shape is illustrated as being a simple rectangular shape.

As provided by the present invention, the lumbar region of the frame has a fabric panel (2) secured to opposite sides of the frame and, as indicated above, this fabric panel is secured to the tubular composite frame during the manufacture thereof. The fabric panel may be a single fabric panel but in this embodiment of the invention is a plurality of different juxtaposed fabric panels located one above the other in which instance they may be tensioned differently according to particular designs and requirements. Also, as the manufacture of the tubular composite frames takes place according to applicant's own technology, the manufacture of the frame itself is also described below for purposes of completeness. In this particular instance the composite frame is produced utilising sheets of fabric reinforcing made of reinforcing fibres that are pre-impregnated with the necessary resin, typically epoxy or phenolic resin, that is sufficient to form the fibre reinforced composite simply by heating whilst applying pressure, as will be described further below. Such pre-impregnated sheets are often referred to in the industry as prepregs and have the advantage that exactly the correct quantity of resin is pre-applied to the sheets of reinforcing fibres at factory level where control is much easier than in an on-site application where layering takes place without serious control of the amount of resin used. Using pre-impregnated sheets therefore avoids the use of too little or too much resin.

Turning now more particularly to the production of the frame described above, and with particular reference to Figures 2 and 7 of the accompanying drawings, accurate placement of the sheets of reinforcing fibres can be achieved by designing the mould such that the main mould surfaces (3) are exposed in the open condition of the mould and are therefore accessible for the placement of pre-cut pre-impregnated sheets (4) in the required positions directly on the prepared mould surfaces.

The placement of the pre-cut, preimpregnated sheets is illustrated schematically in Figure 7 from which it can be seen that the open mould, for the purposes of placement of the sheets of reinforcing material, is of generally outwardly directed angle shape. In order to enable a closed tubular frame to be produced the edges of the sheets project outwards from the mould surfaces sufficiently to enable them to be folded over in order to close the tubular configuration of the frame with a tubular inflatable bladder (5) enveloped in the uncured tubular frame.

The mould, in this instance, consists of a main bottom part (6), a top part (7), and removable sides (8). The top part and bottom part together form an outwardly directed channel shape of the mould when they are engaged with each other as illustrated in Figure 8 and the removable sides close the entire mould cavity as illustrated in Figure 9.

Referring now more particularly to Figure 7, the fabric panel (2) or individual parts thereof, is or are stretched to the required tension across the bottom part of the mould, with the uncured frame already prepared. The top part of the mould is then clamped onto the bottom part in order to hold the fabric panel in tension. A somewhat resilient clamping bead (9) is provided in the top mould part to ensure effective clamping and retention of the required tension in the fabric panel. The clamping bead also serves to prevent resin from reaching areas of the fabric panel between the frame members that may create a hard and uncomfortable feel to parts of the fabric panel.

The top part of the mould also has a rebate (10) to accommodate an overlay (11) of pre-cut pre-impregnated sheets of reinforcing material in order to sandwich the appropriate areas of the fabric panel between the surface of the frame and the overlay.

It will be understood that the fabric panel, in this instance, is secured to surfaces of the frame that are generally coplanar with the panel in the installed condition. In such an instance, and as shown especially in Figures

6 and 7, a reinforcing strip (15) may be attached to the fabric panel so that it becomes located adjacent the frame in the installed condition and passes through a right angle in section so that approximately one half of the width of the reinforcing strip is attached to the side surface (16) of the frame, this attachment being by way of the resin in the manner described above.

However, attachment of the other half to the reinforcing strip to the fabric panel is preferably by way of both adhesive indicated by numeral (17) and at least one line of stitching indicated by numeral (18). In this instance, the adhesive may be different from the resin and may be somewhat flexible so that it can act as a seal between the surfaces of the mould to positively prevent any resin from permeating along the fabric panel. In such an instance the clamping bead (9) may prove to be unnecessary. In the installed condition of the reinforcing strip, the reinforcing strip serves to inhibit the fabric panel from pulling away from the frame in a direction at right angles to the plane of the panel.

Once the fabric panel have been clamped in position in the mould, the outwardly projecting excess of the length of the fabric panel can be trimmed away as will be appreciated from a comparison between Figure 7 and Figure 8.

At this stage, the sides (8) of the mould are then positioned and secured in place in such a fashion as to resist internal pressure applied to the material by the bladder when it is inflated and to define a closed passage enabling a tubular shape to be moulded against the composite duct shaped mould surface defined by the main bottom part, top part and removable sides.

Typically, inlet nozzles (12) (see Figure 2) are provided for supplying compressed air to the bladder (5) in order to inflate it and maintain it in an inflated condition whilst the synthetic resin cures under elevated temperature. The bladder, in operation, is thus pressurized, as is well known in the art, to form and compact the material onto the mould surface and hold it there during the curing process. Accordingly, the bladder together with positive pressure holds the layers firmly in position in the mould during the curing process and assists in ply compaction. Curing may be aided or induced in any manner that is appropriate to the particular resin being used but would typically involve the use of heat.

During the curing procedure, resin penetrates the thickness of the appropriate areas of the fabric panel and becomes fully cured to bond the fabric panel permanently to the moulded frame. It is to be noted that the uncured resin acts as a strong adhesive to bond the fabric panel to the composite material preparatory to and during the curing process. If it is required, of course, additional resin can be added to appropriate areas of the fabric in order to ensure that the fabric becomes properly embedded in resin that becomes one continuous mass with the resin of the frame itself and that of the overlay.

Once the frame has been moulded, both the sides and top of the mould are removed in order to facilitate removal of the moulded frame together with its permanently attached fabric panel. Also, as may be possible or practical, the bladder is removed from the interior of the tubular frame in the usual manner.

It will be understood that numerous variations may be made to the embodiment of the invention described above without departing from the scope hereof. In particular, numerous variations may be made to the process described as would be quite apparent to somebody skilled in the art. Simply by way of example, it is mentioned that a resilient bladder as is indicated above can be replaced by a tubular plastic film that is often referred to as bagging film. Such bagging film, being a relatively lightweight plastic film, is generally not removed following moulding.

Also, the cross-sectional shape of the frame may vary widely and the frame may not be tubular but could be of some other suitable cross-section such as a channel shape, an angle shape, or even that of a solid cross-section such as a bar or rod. In such an instance the use of any bladder or bagging film is obviated.

Numerous other variations may be made to the product and process described above by way of example without departing from the scope of the invention as will be quite apparent to those skilled in the art.

Claims

CLAIMS:

1. A frame and fabric panel assembly comprising a fibre reinforced synthetic resin frame (1) to which at least one fabric panel (2) is permanently secured, the assembly being characterised in that appropriate areas of the fabric panel are secured to the frame by at least partially embedding such appropriate areas of the fabric in synthetic resin that is chemically bonded to the synthetic resin of the frame in order to form said permanent bond.

2. A frame and fabric panel assembly as claimed in claim 1 the appropriate areas are at least a pair of opposite edge or end regions of the fabric panel.

3. A frame and fabric panel assembly as claimed in either one of claims 1 or 2 in which the fabric panel is under a predetermined tension in the installed condition.

4. A frame and fabric panel assembly as claimed in any one of the preceding claims in which the said appropriate areas are secured to a surface of the frame by resin that bonds to resin of the frame.

5. A frame and fabric panel assembly as claimed in claim 4 in which the appropriate areas are sandwiched between the surface of the frame and a fibre reinforced overlay (10) covering said appropriate areas.

6. A frame and fabric panel assembly as claimed in any one of the preceding claims in which the fabric panel is secured to surfaces of the frame that are generally coplanar with the panel in the installed condition in which instance a reinforcing strip is optionally attached to the fabric panel and to another surface of the frame with the attachment of the reinforcing strip to the fabric panel being by way of stitching or adhesive, or both.

7. A frame and fabric panel assembly as claimed in any one of the preceding claims in which the assembly is a component of a vehicle seat assembly or an aircraft seat assembly.

8. A process for the production of a fibre reinforced frame and fabric panel assembly comprising the steps of applying one or more layers (4) of woven or nonwoven fibre reinforcing material and uncured resin to a prepared mould surface (3) to form an uncured fibre reinforced frame having at least a partially exposed outer surface; the process being characterised in that a fabric panel (2) is tensioned in a position over spaced appropriate areas to be attached to the frame that form part of the partially exposed outer surface; ensuring the provision of sufficient uncured resin to at least partially embed said appropriate areas of the fabric panel in uncured resin; closing the mould cavity; causing or allowing the resin to cure to thereby cause the frame to cure whilst permanently securing the appropriate areas of the fabric panel to the frame; and opening the mould and removing the moulded fibre reinforced frame therefrom together with the permanently attached fabric panel.

9. A process as claimed in claim 8 in which the frame is of tubular shape in which instance said one or more layers of fibre reinforcing material and uncured resin are closed to form a tubular configuration around an inflatable bladder (5).

10. A process as claimed in either one of claims 8 or 9 in which the mould is partially closed by clamping top and bottom parts of a mould together to simultaneously clamp the fabric panel to the mould in a tensioned condition.

1 1. A process as claimed in claim 10 in which the fabric panel is clamped to the mould by engaging the fabric panel on the inside of the relevant frame member in which instance excess fabric of the fabric panel is trimmed away prior to final closing of the mould and inflating of any bladder that may be present preparatory to curing of the resin.

12. A process as claimed in any one of claims 8 to 1 1 in which a plurality of different fabric panels are secured to a frame to span different areas of the frame with each fabric panel being tensioned to the same or a different tension.

13. A process as claimed in any one of claims 8 to 12 in which the fibre reinforcing material and uncured resin are in the form of sheets of fabric reinforcing made of reinforcing fibres that are pre-impregnated with the necessary resin that is sufficient to form the fibre reinforced composite simply by heating whilst applying pressure.

14. A process as claimed in any one of claims 8 to 13 in which the fabric panels are positioned and fixed in the mould in such a way as to prevent resin from reaching specific areas of the fabric panel.