AU701387B2 - A method of fixing a panel to a frame - Google Patents

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

II t Name of Applicant: REES OPERATIONS PTY LTD a pe Amethod of performing it known to us.

i e A M a i P cua neno:Jme eneCoa method of performing it known to us. -C C,- This invention relates to an improved composite panel construction and also to a method of fixing a panel to a frame, more particularly the fixing of in-fill panels to square or rectangular frames.

This invention will find numerous applications in various fields, but for ease of description, the invention will be described in relation to the fixing of a solid in-fill panel to a peripheral metal frame. However, it will be realised that the scope of the invention will not be restricted to this particular application.

There are numerous examples where panels, particularly planar panels, need to be fixed to a peripheral frame or frame members. An example can be found in the construction of transportable collapsible containers. Side walls or gates normally comprise a metal frame pivotally attached to a pallet base. Four separate pivotal 1 gates are secured to the base to form the required container.

In some cases, it is necessary for a storage container to hold fine particulate material, or small articles. In such cases, it is a requirement for the side walls of the container to be solid rather than comprising conventional mesh material.

Such solid walls would also be required in the case where the storage containers hold fluid. In this case, a bladder or plastic membrane is planed within the container so that it is fluid tight. A common technique to form the walls of a container is to fabricate a rectangular frame from tubular or angle section metal. A panel, which m y comprise a polycarbonate sheet is then affixed to one side of the frame, normally with the use of rivets. In this case, apertures are drilled through the polycarbonate sheet and into the tubular steel. The polycarbonate sheet is then held in place by pop rivets.

One serious disadvantage with this method is that there is a significant difference between the co-efficient of expansion of the metal frame and the polycarbonate sheet.

4o Even though sufficient clearance is provided between the rivet and the polycarbonate sheet by drilling an oversize hole, this is still not sufficient to prevent 4)P I J, distortion of the polycarbonate sheet. A common problem is expansion of the polycarbonate sheet between rivets so that there is an outward bowing of the sheet around the frame edges. This produces an unsightly appearance.

In addition, the constant expansion and contraction of the polycarbonate sheet against the rivet fixings result in cracking of the sheet around the rivet holes. The drilling of the polycarbonate sheet results in a rough surface which in itself is a stress raiser and allows propagation of cracks.

Cracking of the polycarbonate sheet is at its worst when containers are used in freezer storage applications. The polycarbonate sheet loses its elasticity in colder S: L conditions, and the plastic sheet is prone to cracking under tensile loading which results from contraction in cold conditions.

15 Therefore, it is an object of this invention to overcome the abovementioned problems and to also provide a means of fixing a panel to a frame that is cheap, cost effective and simple to manufacture.

In its broadest form, the invention is directed to a method of fixing a plastics sheet in- 20 fill panel to an outer frame having a plurality of elongate metal outer frame members, the method comprising the steps of: rigidly securing elongate metal channel members, each having spaced apart flanges defining a channel opening therebetween, to respective said outer frame members with their channel openings facing inwardly, locating peripheral edge portions of said panel into respective said channel openings, and pressing the flanges of the said channel members together so as to close against opposite wall surfaces of said panel so that the panel is clamped between the flanges and is thereby fixed within the outer frame.

The invention may comprise a single elongate frame member having means for securing one edge of a panel thereto. Preferably, the invention is utilised with a square or rectangular metal frame having four interconnected elongate metal frame members, with a channel member secured to each of the outer frame members.

Preferably, each of the chamel members has a substantially V-shaped cross-section with the apex of the channel being secured to a respective frame member so that it extends longitudinally thereof. The channel may be simply tack welded into place, but can, however, be secured by using other fixing means.

Preferably, the channels are affixed to the outer frame members so that the panel lies approximately co-planar with the plane of the outer frame. Alternatively, the channels may be secured to outside surfaces of the frame members so that when the panel is clamped in place, the panel lies in a plane displaced from the plane of the outer frame.

By a press or other means, one or both of the flanges of the channel members are •squeezed together or closed and forced against opposite sides of the panel.

o 15 Preferably, the panel comprises a material which is slightly compressible, and by applying sufficient force, effective sealing between the panel and the channel flanges can be obtained, even though there is some slight opening or rebounding of the channel due to elasticity of the channel material.

20 In order to assist in holding the panel in position, an adhesive material may be located on the interior surface(s) of each of the channel members. This will inhibit any movement or rattling of the panel within its frame. The use of the adhesive, particularly an adhesive which has the required creep characteristics, will permit thermal expansion of the polycarbonate sheet with respect to the frame. Therefore, the polycarbonate sheet is able to readily contract or expand while at all times being securely held to the inside surface of the channel member. In this regard, the panel is sized to provide ample clearance for expansion around its periphery with respect to the base of the channel.

Preferably, the adhesive material is double-sided tape. The double-sided tape, together with its removable cover strip, can be located readily on one or both of the inside surfaces of the flanges of the channel. The panel can then be inserted and

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located in place, and the tape cover strip removed, whereupon the panel will adhere to the tape.

Preferably, the adhesive material is placed on the inside surface of the channel member on the side against which the panel is normally forced. Therefore, in a loaded pallet container, where the panel is always forced outwardly, then the adhesive material is placed on the inside surface of the outer flange of the channel member.

Preferably, the channel member is welded to its frame member so that the plane of one of the flanges of the channel member is parallel to the plane formed by the outer frame, the other flange being disposed obliquely to said plane. This canting of the channel with respect to the frame provides a greater opening for location of the panel therein. In fact, it is possible to cut the panel to the exact size so that it matches the 15 dimensions of the opening defined by the free edges of the canted sides of the channel members. In this case, the panel will simply drop in place, and the pressing operation will deform the canted sides of the four channel members against the panel so that the panel edges are clamped between the flanges of the channel members, whereby the panel is firmly held along its four sides with respect to the outer frame.

The free edges of the flanges of each of the channel members are preferably kicked inwardly so that an edge portion of each side of the channel is at an angle with respect to the remaining side of the channel. This slight kick-in, by approximately 10-15', results in a more positive sealing effect when the flanges of the channel are pressed against the panel. In the pressing operation, there is a slight flattening of the kick-in, and this feature, combined with the compressibility of the panel material, will enhance the sealing effect. It also means that, where adhesive is used, the panel will not fully come into contact with the adhesive material until the final pressing operation is complete. This will allow some movement of the panel prior to the pressing operation to allow final adjustment of its position. In addition, the "kickedin" edges of the flanges reduces the likelihood of a person's fingers being "caught" on the free edges of the channel members. No sharp edges will be presented.

I r I~ I i In order that the invention may be fully understood, a preferred embodiment will now be described, with reference to the accompanying drawings in which: Fig 1 is a plan view of a composite metal/plastics panel assembly for use in a collapsible container, made in accordance with the method of the present invention; Fig 2(a) shows the cross-sectional view of a frame member, channel and panel prior to the pressing operation, Fig 2(b) shows, in cross-section, a frame member, channel and panel after the pressing operation; while Fig 3 is a view similar to Fig 2(b) of a panel assembly where adhesive is used inside 15 of the channel member to assist in holding the panel in place.

Referring to Figs 12(a) and 2(b) of the drawings, a composite panel assembly comprises an outer frame 11 comprised of four elongate tubular metal outer frame members 12,13, a plastics sheet in-fill panel 14, and four inner metal channel 20 members 15, 16 which are respectively secured to the outer frame members 12, 13 and clampingly retain the panel 14 to the outer frame 11.

In this embodiment, each of the channel members 15, 16 is rigidly fixed to its corresponding frame member 12,13 by tack welding at intervals along its length, withl the closed side of each channel member being joined to inner end wall 17 of its associated outer frame member 12,13.

In this embodiment, each panel assembly 10 is rectangularly shaped and is designed to be attached to a pallet base (not drawn) in order to form the sides of a container.

The upper and lower frame members 12 are butt welded to the ends of the vertical side frame members 13 to form the frame 11. Each of the frame members 12 has i welded thereto a long channel member 15 while each of the frame members 13 has C- welded thereto a relatively short channel member 16, the lengths of the channel members 15, 16 being selected so that the inner corner regions of the frame 11 are left open. If desired, the channel members can extend into the corner regions and be joined together by means of mitred joints so as to provide a neat appearance.

As seen in Fig 2(a) each of the channels 15, 16, prior to the pressing operation, has a substantially V-shaped cross-section. Each channel 15, 16 has opposed flanges or legs 21 and a rounded apex or bridging portion 23. The edges of the side walls 20, 21 are formed to produce in-turned lips 24 which are at an angle of approximately 15' with respect to the planes of their associated flanges 20, 21.

Fig 2(a) shows the panel 14 having an edge portion positioned within the recess of the channel 15 prior to the pressing operation. The channel 15 is attached to the frame member 12 so that its flange or leg 20 lies in a plane approximately parallel to o 15 the plane of the outer frame 11. This results in the free edge of flange 21 being higher with respect to the free edge of flange 20 when viewed from the side. Provided the polycarbonate panel 14 is dimensioned correctly, it can be simply dropped into place, with the peripheral edges of the panel 14 clearing the free edges of the flanges 21, and the edge portions of the panel 14 locating against the flanges Once the panel 14 is in position, a pressing operation is carried out to close the flanges 20, 21 of the channels 15, 16 around the sides of the panel 14 so that the panel 14 is permanently clamped in position by the channels 15, 16. The result after the pressing operation is illustrated in Fig In the pressing operation, sufficient force is applied on either side of each of the channels 15,16 to cause flattening of their inturned lips 24. It is desirable that the pressing operation closes the channels 15, 16 sufficiently so that when the pressing force is released, there will be very little clearance between the inner surfaces of the flanges 20, 21 and the panel 14. In addition, the edges of the lips 24 will tend to "dig" into the surface of the slightly compressible polycarbonate sheet thereby providing an additional amount of i Ssealing.

71 CL-- IIL I However, the degree of sealing will still be surface contact equivalent to an interference fit of the panel 18 within the channel 11. This will not prevent the panel 14 from moving with respect to the channel 11 when thermal expansion or contraction occurs.

In a variation to the abovedescribed embodiment, which is shown in Fig 3, doublesided adhesive tape 28 is attached to the inside surface of the flange 20. Prior to the installation of the panel 14, the cover strip on the tape 28 is left in place. The cover strip can be removed once the panel 14 is located in position. As soon as the cover strip is removed, the tape 28 will adhere to an edge portion of the panel 14. The panel 14 will initially rest on the kicked-in lips 14 so that only the peripheral edges of the panel 14 will initially be in contact with the tape 28. However, this will be sufficient to provide an initial fixing of the panel 14.

Desirably, the tape 28 is adhered to the outer flanges only of the channels 15, 16 so that, when in use, load which is applied to the inner side of the panel 14, will tend to force the panel 14 against the adhesive tape 28 thereby ensuring continual contact and adhesion.

As seen in Fig there is sufficient clearance between the outer edge of panel 14, and the base or rounded apex 23 of the channel 15, so that the panel is reasonably free to move when undergoing expansion or contraction. In addition, the rounded apex 23 of the channel 15 is dimensioned so that the panel 14 will comfortably fit within the channmel 15 after the pressing operation, with its flanges 20, 21 converging slightly inwards. This, along with the in-turned lips 24, reduces the likelihood of any "sharp" edges of the channels being exposed.

As mentioned above, the channels 15, 16 are tack welded to the frame members 12, 13 and it is convenient to carry out any plating operations or corrosion protection applications prior to location of the panel 14 and tape 28.

Claims (17)

1. A method of fixing a plastics sheet in-fill panel to an outer frame having a plurality of elongate metal outer frame members, the method comprising the steps of: securing metal channel members, each having spaced apart flanges defining a channel opening therebetween, to respective said outer frame members with their channel openings facing inwardly, positioning the panel with its peripheral edge portions projecting into respective said channel openings, and pressing the flanges of each said channel member so as to close same against i ""opposite wall surfaces of said panel so that the edge portions of the panel are clamped between the flanges of said channel members to thereby fixedly hold the panel within said outer frame. o.

2. A method according to claim 1 wherein said metal channel members are secured to respective said outer frame members by welding.

3. A method according to either claim 1 or claim 2 wherein said metl3 channel o 20 members are secured to inner surfaces of said outer frame members and extend longitudinally thereof.

4. A method according to any one of the preceding claims wherein each said channel member, prior to tile pressing step, has a substantially V-shaped cross- section and is secured to its associated said outer frame member with one of its flanges disposed approximately at right angles to the longitudinal axis of said associated frame member, its other flange extending obliquely with respect to said axis.

5. A method according to any one of the preceding claims wherein the flanges of each said channel member terminate in slightly in-turned planar lips which, during the pressing step are substantially flattened. L

6. A method according to any one of the preceding claims further comprising the step of applying adhesive material to the inner surface of one or both of the flanges of each of the chamnnel members prior to the step of positioning said panel whereby, when the panel is thus located and the flanges duly pressed together, edge portions of the panel adhere to the adhesive material.

7. A method according to any one of the preceding claims wherein said plastics in-fill panel is formed from polycarbonate sheet.

8. A composite metal/plastics panel assembly produced by the method I according to any one of claims 1 to 7. t 0 I

9. A composite panel assembly comprising: 15 an outer peripheral frame formed by a pl arality of elongate metal outer frame members, a in-fill panel of plastics sheet material, a plurality of metal channel members secured to said outer frame members so as to extend around the inner periphery of said outer frame, each said channel member having spaced apart flanges defining an inwardly facing panel receiving channel opening, S. wherein edge portions of said panel are clampingly retained between the flanges of said channel members, said panel being fixed within said outer frame by placing edge portions of the panel into said channel openings and thereafter closing the flanges of each said channel member against opposite wall surfaces of the panel.

A composite panel assembly according to claim 9 wherein said metal channel members are secured to their associated said outer frame members by weld means.

11. A composite panel assembly according to either claim 9 or claim 10 wherein said panel is sized so that a clearance exists between its periphery and the base or closed end of each of the channel members. 1 n 1_

12. A composite panel assembly according to any one of claims 9 to 11, wherein said panel is square or rectangular in shape and its four sides are clampingly retained by four said channel members which extend longitudinally of their associated said outer frame members.

13. A composite panel assembly according to any one of the preceding claims wherein said panel is formed of polycarbonate sheet material.

14. A composite panel assembly according to any one of the preceding clal wherein said outer frame members are formed of metal tube, which is rectangular or square in cross-section. i S

15. A composite panel assembly according to any one of the preceding claims .0 o 15 further comprising adhesive material located on the inner surface of one or both of the flanges of each said channel member, said edge portions of the panel adhering to adhesive material so as to inhibit vibrational or rattling movement of the panel within its channel members.

16. A method of fixing a plastics sheet in-fill panel to an outer peripheral frame substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

17. A composite panel assembly substantially as hereinbefore described with reference to and as illustrated in the accompany drawings. Dated this 3rd day of October, 1996. REES OPERATIONS PTY LTD By its Patent Attorneys MADDERNS ;1 e~Mc ABSTRACT The invention provides an improved method of fixing a plastics sheet in-fill panel (14) to an outer frame (11) in order to form a composite panel assembly The panel (14) is secured around its periphery by means of metal channel members 16) which are respectively secured to the outer frame members (12, 13) of the outer frame The flanges (20, 21) of the channel members (15, 16) are squeezed together by means of a pressing operation in order to clamp the peripheral edge portions, "f the panel (14) therebetween. The flanges of each of the channel members 16) are, prior to the pressing operation, widely spaced apart at their free ends so as to allow the panel (14) to be located in position with its edge portions respectively located partly within the channel openings of the channel members (15, 16). t S 'i i. lr t C c