GB2108573A - Corner clip - Google Patents

Abstract

A corner clip for fitting to the corner of an open top box or tray retains the corner of the tray erected and is retained in position by one of more protuberances 10 which engage the inner vertex of the corner of the box or tray. The clip is formed with two pairs of inner (3) and outer (2) wall portions adapted to slide over the adjacent walls of the tray corner with a support platform 1 lying substantially parallel to the base of the trays. <IMAGE>

Description

SPECIFICATION Corner clip This invention relates to improvements in or relating to a corner clip for fitting to the corners of an open box or tray folded from a flat blank of cardboard, fibreboard or like material to provide a stacking surface so that a number of such boxes or trays may be stacked upon each other.

To minimise the risk of a corner clip being misplaced various constructions of corner clip have been proposed whereby the clip is secured in position on the corner of the box or tray. For example it has been proposed to provide a corner clip in which two mutually perpendicular outer wall members depend downwardly from the stacking or support platform of the clip to contact the outside of the tray corner and three clamping plates, also depending from the support platform, have smooth edges which engage edgewise with the inside of the tray corner, two of the clamping plates being perpendicular to respective walls and one directed to the intersection of the walls at an angle of 450 to the walls.In order to obtain adequate grip of the clip to the tray the clearance between the smooth clamping edges of the clamping plates and the outer wall members has to be such that the clips can be difficult to apply, particularly when bulking of the tray material occurs on the inside vertex of the corner of the tray.

It has also been proposed to provide a corner clip having a support platform from which depend two outer wall portions ar right angles to one another and two inner wall portions inwardly spaced from respective outer wall portions. The spacing between the inner and outer wall portions is such as to allow the clip to be fitted over the corner of a box or tray. To retain such clips in position there can be provided spaced tray gripping surfaces on the inner and outer wall portions which deform the tray material out of the plane of the tray wall to resist subsequent movement of the clip. The more rigid the tray material is the more difficult it is to apply such a clip to a tray.

Other proposals have been made to provide a protuberance on either the inner or outer wall portions of the clip which protuberance engages a downwardly facing ledge formed by a slit, slot or aperture in the tray or by a turned over edge of the wall of the tray. Unless the tray is accurately made this allows a degree of freedom of movement of the clip relative to the tray before the protuberance engages the ledge on the tray.

Yet another proposal is to provide a series of protuberances having upwardly facing gripping edges parallel to the support platform on both the inner wall portions of the clip together with further such gripping edges extending diagonally across the intersection of the inner wall portions inwardly spaced from the intersection.

According to the present invention there is provided a corner clip for fitting to a corner of a tray folded from a blank of cardboard comprising a support platform, two pairs of inner and outer wall portions each of said pair being adapted to slide over one of the adjacent walls of the tray corner with the support platform substantially parallel to the base of the tray, and at least one board engaging protuberance terminating in a point lying substantially along the line of intersection of the planes of the two inner wall portions.

When fibreboard is creased and folded to form a corner there is a bulking of the fibreboard along the inner vertex of the corner. This bulking tends to cause a certain amount of delamination at the corner which enables the point of the protuberance on the clip according to the present invention to obtain a much more positive grip with the bulked material than with the flat material.

Thus the grip of the clip is more secure than in the previously proposed constructions which grip the flat material and the clip can nevertheless be applied to the tray without having to use undue force. It has been found that no other board gripping means need be provided to retain the clip in position. One or both of each pair of the inner and outer wall portions can be resiliently movable with respect to the other of the pair to enable the clip to be used with trays of different caliper of board material thereby avoiding any undue multiplicity of clips for different board material and the attendant expense and risk of confusion of different clips of similar appearance.

Conveniently the two inner wall portions are interconnected to increase the rigidity of the clip and the board engaging protuberance is formed at their interconnection.

The board engaging protuberance is.

advantageously barb-like with a lower surface, facing away from the support platform, inclined to the line of intersection of the planes of the two inner wall portions to facilitate the application of the clip to a corner of a tray. Preferably the lower surface of the barb is formed by two inclined surfaces which meet to form an intersection line lying in a plane intersecting the planes of the two inner wall portions at an angle of 450 and extending from the point of the barb to lie inclined to the line of intersection of said planes.

The intersection line of the two lower surfaces of the barb form a line contact between the barb and the inner corner of the tray as the clip is being fitted thereby minimising the force required to apply the clip.

More than one such protuberance can be provided to further enhance the grip.

The invention also provides an open top box or tray having a base member, side walls upwardly folded from the base member to surround the base member, adjacent side walls meeting one another at right angles and each sidle wall at each corner having an extension flap extending in contact with the adjacent side wall and a corner clip at each corner comprising a support platform, inner and outer wall portions spaced apart to receive the side walls and extension flaps, and a board engaging protuberance adapted to engage with the inner vertex of the corner. The corner clips hold the two extension flaps at each corner folded around so preventing the tray from unfolding.Nevertheless because the clip is retained in position by engagement of the clip with the inner vertex of the corner the width between the inner and outer wall portions of the tray is not critical with respect to the thickness of the board since the board does not have to be clamped therebetween in order to retain the clip in position. Even if the distance between the inner and outer wall portions of the clip is slightly greater than the combined thickness of the side wall and extension flap the clip will satisfactorily grip the inner vertex of the corner. The outer wall portions of the clip can be resilient to accommodate varying thicknesses of board.

The invention will now be more particularly described with reference to the accompanying diagrammatic drawings in which: Figure 1 is a perspective view from below of a corner clip according to the invention; Figure 2 is a side elevation of the clip of Figure 1; Figure 3 is an underneath plan view of the clip; Figure 4 is a plan view from above of the clip; Figure 5 is a plan view of a blank for forming a tray; Figure 6 is an enlarged plan view from above of one corner of a tray erected from the blank of Figure 5; and Figure 7 is a view of part of the clip as shown in Figure 1 on an enlarged scale.

Referring to Figures 1 to 4 and 7 there is shown a corner clip which is moulded from plastics material such as polypropylene and having a substantially triangular support platform 1 from which extend two outer wall portions 2 and two inner wall portions 3. The inner wall portions are of such a length that the bottom edges 4 thereof can contact the base of a tray to which the clip is fitted.

The inner wall portions are interconnected by an interconnecting strip 5 extending diagonally to the two inner wall portions. The outer members 2 can flex in the region 6 so as to be resiliently spaced from the inner wall portions. Respective inner and outer wall portions each form a pair of wall portions which are adapted to slide over the side walls at a corner of an open top tray or box.

Extending from the support platform 1 in the direction opposite to the wall portions 2 and 3 are shoulders 7, 8 which assist in locating the bottom corner of a box or tray stacked upon the support platform of the clip.

To maintain the clip in position two barb-like board engaging protuberances 9 are formed on the strip 5. The protuberances terminate in points 10 lying substantially along the line of intersection of the planes of the two inner wall portions and each have two lower surfaces 11 which face away from the support platform inclined to the line of intersection of the planes of the inner wall portions. The lower surfaces 11 meet to form an intersection line 11 a extending from the point 10.

The intersection lines 11 a are inclined to the aforesaid line of intersection of the planes of the two inner wall portions and lie in a plane intersecting those planes at an angle of 450.

Referring now to Figure 5 there is shown a blank of solid fibreboard having a base member 12 having side wall panels 13 foldably connected to each of the edges thereof. The side wall panels 13 have extension flaps 14 at each end which when the side walls are erected fold around to contact the adjacent side wall panels. To maintain the tray erected the corner clip of Figures 1 to 4 is slid upon the corners of the tray so that the extension flaps are retained in position by the pairs of inner and outer wall portions 2 and 3.

Figure 6 shows an enlarged fragmentary corner of a tray. The creasing and folding of the fibreboard results in the fold between the innermost side wall panel 13 and its extension flap forming a bulk of fibreboard 1 5 inside the vertex of the corner. This bulk of fibreboard tends to be somewhat delaminated by this folding and creasing. The fold between the outermost side wall panel and its extension flap 14 connected thereto follows a larger radius of curvature and bulking of the inner corner of this fold is to some extent at least prevented by the inner fold.

When the clip of Figures 1 to 4 is being fitted to the corner the inclined intersection line 11 a forms a line contact with the inner vertex of the tray to facilitate the clip being slid into position. Once in position the points 10 of the protuberances engage the bulk of fibreboard material at the vertex of the tray corner and minimise the risk of the clip being accidentally displaced.

The spacing between the pairs of inner and outer wall portions 2 and 3 of the clip is preferably such that the outer wall portions are urged outwardly by a small distance when the clip is fitted. Firm retention of the clip is however assured even when the spacing between the pairs of inner and outer wall portions is slightly greater than twice the thickness of the fibreboard material since the bulking 1 5 will nevertheless still be present and the tendency of the flaps 14 to spring back and align with their respective wall panels tends to force the inner vertex of the corner into engagement with the barbs.

Thus the clip can be very easily applied without the need for excessive force and a single design of clip can be used for a greater variety of board thicknesses than hitherto. The necessity for die cut tray blanks as are required for some of the hitherto proposed clips is also avoided.

Claims (8)

1. A corner clip for fitting to a corner of a tray folded from a blank of cardboard comprising a support platform, two pairs of inner and outer wall portions each of said pair being adapted to slide over one of the adjacent walls of the tray corner with the support platform substantially parallel to the base of the tray, and at least one board engaging protuberance terminating in a point lying substantially along the line of intersection of the planes of the two inner wall portions.

2. A clip according to Claim 1 in which one or both of each pair of the inner and outer wall portions are resiliently movable with respect to the other of the pair.

3. A clip according to Claim 1 or Claim 2 in which the two inner wall portions are interconnected and the board engaging protuberance is formed at their interconnection.

4. A clip according to any one of the preceding claims in which the board engaging protuberance is barb-like with a lower surface, facing away from the support platform, inclined to the line of intersection of the planes of the two inner wall portions.

5. A clip according to Claim 4 in which the lower surface of the barb is formed by two inclined surfaces which meet to form an intersection line lying in a plane intersecting the planes of the two inner wall portions at an angle of 450 and extending from the point of the barb to lie inclined to the line of intersection of said planes.

6. An open top box or tray having a base member, side walls upwardly folded from the base member to surround the base member, adjacent side walls meeting one another at right angles and each side wall at each corner having an extension flap extending in contact with the adjacent side wall and a corner clip at each corner comprising a support platform, inner and outer wall portions spaced apart to receive the side walls and extension flaps, and a board engaging protuberance adapted to engage with the inner vertex of the corner.

7. A corner clip for fitting to a tray folded from a blank of carboard substantially as hereinbefore described with reference to the drawings.

8. An open top box or tray and a corner clip at each corner substantially as hereinbefore described with reference to the drawings.