GB2370033A

GB2370033A - Container corner connectors

Info

Publication number: GB2370033A
Application number: GB0026506A
Authority: GB
Inventors: Freidlander Uri
Original assignee: TWINPLAST Ltd
Current assignee: TWINPLAST Ltd
Priority date: 2000-10-30
Filing date: 2000-10-30
Publication date: 2002-06-19
Also published as: GB0026506D0

Abstract

An open topped flat pack container, with or without a lid, is formed from a blank having a central base portion and flanking side wall portions and end wall portions that are folded upwardly to form the walls of the container. Each corner of the container is held together in the assembled state by a respective corner connector (24a-24d), wherein each corner connector comprises a pair of arms, the arms subtending an angle therebetween corresponding to the angle of the corner. Each arm has a channel extending therealong, the channel being internally stepped so that it has a relatively broad first part of its depth to fit over a relatively thick container wall and has a narrower second part to its depth, approaching the bottom of the channel, to more closely accommodate a narrower container wall. The connector can therefore engage over edges of inner flaps of the container which are spaced below the top edge of the corresponding wall.

Description

IMPROVEMENTS TO FLAT PACK CONTAINERS

Field of the Invention The present invention concerns improvements in and relating to flat pack containers and especially open topped (or lidded) flat pack containers.

Background to the Invention Open topped flat pack containers which may alternatively be referred to as trays (but without any implied limitation on the relative height of the side/end walls) are used for storage, transportation and/or display of a wide range of goods from electrical and mechanical components or appliances through to food products such as fruit and vegetables.

The flat pack open top containers/trays with or without a lid traditionally have been constructed from a card board blank folding along pre-defined lines to form the side walls and end walls around the central portion of the blank that serves as the base of the container. An example blank for a container is illustrated in Figure 1 and comprises a central base portion 1 flanked on either side by side wall portions 2a, 2b and at each end by end wall portions 3a, 3b. In the illustrated conventional example it will be noted that the side wall portions 2a, 2b each have a secondary end wall portion 2c, 2d, 2e, 2f at each end that is adapted to be folded to lap with one of the endwalls 3a, 3b.

For most trays made of corrugated cardboard the side walls and end walls are, once folded to their upright configuration, normally secured together by the secondary end walls on each side wall being stapled in place to the corresponding end wall 5. Where the trays are intended to be stacked one atop another, the comers of the tray would normally be re-inforced by a respective wooden post in each one or by additional portions of repeatedly folded card board that alternatively serve as posts.

In recent years the development and mass manufacture of corrugated plastics boards has greatly increased the diversity and capabilities of flat pack trays.

Corrugated plastics boards have the substantial benefit of greatly improved structural rigidity over corrugated cardboards and are now used quite commonly in the construction of flat pack trays that are stackable once assembled.

Taking a blank of corrugated plastics board having generally the same shape as illustrated in Figure 1 and folding the side walls 2a, b and secondary end walls 2c, 2d, 2e, 2f and end walls 3a, b to their upright configuration, the side walls and end walls are conventionally secured together not by stapling the secondary endwalls 2c-f to the endwalls 3a, b but instead by the use of special corner connector moulding 4 such as illustrated in Figure 2. These corner connectors 4 have two arms 5a, 5b at right angles to each other to define a right angled corner.

The arms 5a, b each comprise a respective base plate portion 6a, 6b having a respective ledge 7a, 7b that projects inwardly, i. e. into the interior of the assembled tray, and then downwardly to define a channel 8a, 8b into which the upper most edge of the end wall 3a, b or side wall 2a, b, as the case may be, fits.

Generally, the corner connector 4 will not be fitted directly to the corrugated plastics upper edge of the end wall 3a, b or side wall 2a, b. Instead, the upper edge of the end wall 3a, b or side wall 2a, b is normally capped with a rigid extruded plastics rail 9 which would normally be riveted to the respective end wall/side wall or otherwise fastened in place. The rail 9 has a uniform"U"-shaped cross-section.

Bearing in mind that it is common to construct corrugated plastics board flat pack trays with a blank substantially as illustrated in Figure 1, i. e. having double thickness end walls 3a, b and single thickness side walls 2a, b, the corner connector 4 generally has to be formed with asymmetry about the corner axis since the channel 8a that fits over the side wall needs to be narrower than the channel 8b that fits over the double thickness end wall. The net consequence of this asymmetry is

that the connectors 4 must generally be supplied in both"left-handed"and"righthanded"forms in order to suit the different corners of the tray. Furthermore, the rails 9 must also usually be supplied in two forms-wide channel for the double thickness end walls and narrower channel for the sidewalls. For the manufacturers this means needing to have additional moulds for the different respective corner moulding and rail extrusions and for the tray assembler there is the inconvenience of having to maintain stocks of two different types of corner connector for each tray and two different types of rail.

It is a general objective of the present invention to address this problem, amongst others, of the prior art.

Summary of the Invention According to a first aspect of the present invention there is provided an open topped flat pack container, with or without a lid, which is formed from a blank of a sheet of board material having a central base portion and flanking side wall portions and end wall portions that are folded upwardly to form the walls of the container, each corner of the container being held together in the assembled state by a respective corner connector, wherein each corner connector comprises a pair of arms, the arms subtending an angle therebetween corresponding to the angle of the corner, each arm having a channel extending therealong, the channel being internally stepped so that it has a relatively broad first part of its depth to fit over a relatively thick container wall and has a narrower second part to its depth, approaching the bottom of the channel, to more closely accommodate a narrower container wall.

Preferably the first channel part is approximately twice as broad as the second channel part so that it may accommodate a double thickness wall of the container while the second channel part accommodates relatively closely a single thickness wall of the container.

Ultimately, by giving the channel a stepped profile to accommodate differing thicknesses of wall, it is possible to form the connector to be substantially symmetrical about the corner axis or, more specifically, to have the respective arms with substantially the same channel profile, thereby avoiding the need for righthanded and lefthanded corner connectors and the connector can accommodate a single stepped profile of rail rather than different width channel rails.

Particularly preferably, the corner connector is formed so that the channel walls have a degree of resilience to slightly resiliently close toward each other to grip a container wall fitted therein.

One or more lug means are suitably provided within the channel and preferably in the first part of the channel to grip the container wall and, preferably to slot into a corresponding slot formed in the the container wall. By this means it is possible to firmly secure the connector in place and, for that matter, to secure any rail (s) in place without need for rivetting or other separate fastening means.

Preferably the arms of the connector comprise a pair of base plate portions subtending an angle therebetween corresponding to the angle of the corner, each base plate portion having a ledge projecting inwardly (i. e. towards the interior of the container) therefrom and which then extends as a retaining wall downwardly to define between it and the base plate portion a channel part having a first width and which then extends in a step inwardly again and then downwardly again to define a channel part of greater width than said first width channel part whereby the comer connector at each corner of the tray fits over the container side wall with the side wall extending into the first width part of the channel and over the container end wall with the end wall extending into the wider part of the channel.

According to a second aspect of the present invention there is provided a kit of parts for a flat pack open top container and which comprises a blank sheet of board material having a central base portion and flanking side wall portions and end

wall portions that can be folded upwardly to form the walls of the container, each corner of the container being able to be held together in the assembled state by a respective corner connector, the kit having a plurality of corner connectors wherein each corner connector comprises a pair of arms, the arms subtending an angle therebetween corresponding to the angle of the corner, each arm having a channel extending therealong, the channel being internally stepped so that it has a relatively broad first part of its depth to fit over a relatively thick container wall and has a narrower second part to its depth, approaching the bottom of the channel, to more closely accommodate a narrower container wall.

Preferably the kit further comprises a plurality of rails to fit over the top edge, in use, of the side and/or end walls of the container, respectively, and which will fit into the channel of the connectors. These rails are particlarly preferably shaped to have a similar stepped profile to the corner connector channel to be able to fit closely to the corner connector whereby the rails are held firmly in place with no need for alternative fastening means and whereby the rails for the side walls may be the same as the rails for the end walls.

According to a fourth aspect of the present invention there is provided a corner connector for use to hold together an edge wall and side wall of an open topped flat pack container, which comer connector comprises a pair of arms, the arms subtending an angle therebetween corresponding to the angle of the comer, each arm having a channel extending therealong, the channel being internally stepped so that it has a relatively broad first part of its depth to fit over a relatively thick container wall and has a narrower second part to its depth, approaching the bottom of the channel, to more closely accommodate a narrower container wall.

Preferably the comer connector is provided with one or more lugs that project into the channel and particularly preferably these project from the base plate into the wider part of the channel.

Brief Description of the Drawings Figure 1 is a plan view of a blank for an open topped container, being of conventional design.

Figure 2 is a perspective view of a conventional comer connector.

A preferred embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, wherein Figure 3 is a perspective view of the corner connector of the preferred embodiment; Figures 4 and 5 are respectively a plan view of the preferred embodiment of connector of Figure 3; Figure 6 is an end elevation view of the preferred embodiment of connector; Figure 7 is an end elevation view of a stepped rail for use with the corner connector of the present invention; Figure 8 is an"exploded"perspective view of a flat pack open top container embodying the invention; Figure 9 is a perspective view of the container of Figure 8 fully assembled; and Figure 10 is a plan view of a blank for the container of Figures 8 and 9.

Description of the Preferred Embodiment Referring to Figure 3, the preferred embodiment of corner connector shares in common with the prior art connector of Figure 2, the general construction comprising a pair of arms 5a, 5b each having a base plate portions 10a, 1 Ob the arms 5a, 5b substending an angle between them of 900 to suit a right angled tray corner. A ledge 11 projects inwardly (i. e. toward the tray interior) from the base plates 10a, b and then downwardly to serve as a retaining wall 13. In contrast to the

connector of Figure 2, however the ledge 11 is the same width for both arms 5a, 5b of the connector being a width to suit a single thickness endwall, and the lowermost portion of the retaining wall 13 extending downwardly from the ledge projects inwadly again to form a second ledge 12 before extending downwardly again.

As will be appreciated, and as can be readily seen from Figures 4 to 6, the corner connector is substantially symmetrical about the comer axis having the same profile for each of the two arms 5a, 5b. Of particular significance is the fact that the profile defines a stepped channel that is the same for each of the arms 5a, 5b of the connector 4.

The upper part of the retaining wall 13 depending from the upper ledge 11 defines a relatively narrow single thickness channel portion 20a whereas the lower part of the retaining wall 13 depending from the second ledge 12 defines a channel portion 20b of substantially double the width suitable to accommodate the double thickness end wall 3a, b of a tray. By the simple further expedient of slightly shortening the height of the secondary end wall portions 2 c-f of the end wall 3 relative to the side wall 2 this universal corner connector can be used for any corner of the container (See Figure 8).

In further contrast to the prior art corner connector 4, the corner connector of the present invention as illustrated in Figures 3 to 6 is provided with apertures 21 in the first ledge 11 of its juncture with the base plate 5a, b. These are essentially a feature of the moulding process but may allow some extra resilient flexure of the retaining wall 13 relative to the base plate 5a, b. Flexure of the retaining wall 13 relative to the base plate 5a, b enables the connector 4 to resiliently grip the side wall and/or end wall of the tray and any rail 9'on the side wall and/or end wall.

Further important enhancement of the grip is provided by a number of lugs 22 protruding from the inner face of the base plates 5a, b as can best be seen in Figures 3 and 6.

The lugs 22 co-operatively engage with elongate slots 31 in the side and end walls of the container locking the connector 4 to the side/end walls 2, 3 and trapping the rails 9'in place.

As will be seen from Figure 7, the rails 9'used with the connector 4 are similarly stepped in profile to the stepped channel 20 of the connector 4 and seat within the channel 20, nesting in the channel 20, and with the outer wall of the rail 9' shorter than the inner wall of the rail 9'resting on and trapped above the lugs 22.

Turning to Figures 8 and 9 the"universal"stepped corner connectors 4 and corresponding universal stepped rails 9'of the present invention assemble neatly together with the container body 29 (comprising the erected blank with bare sidewalls 2 and endwalls 3). The illustrated completed container has four substantially identical corner connectors 4 (24a-d in Figure 8) and rails 9 (30a-d in Figure 8). Additional features include a separate lid 23, partition elements 25 and supports therefor 26 and handle/label holder mouldings 27a, b at each end of the container.

By the measures provided in the corner connector of the present invention not only is it easier, simpler and cheaper to make and assemble the flat pack tray by virtue of the universality of the corner connector, the features which assist grip by the corner connector help to obviate the need for rivetting of any rail to the side walls 2, for example.

Claims

1. An open-topped flat pack container, with or without a lid, which is formed from a blank of a sheet of board material having a central base portion and flanking side wall portions and end wall portions that are folded upwardly to form the walls of the container, each comer of the container being held together in the assembled state by a respective corner connector, wherein each corner connector comprises a pair of arms, the arms subtending an angle therebetween corresponding to the angle of the corner, each arm having a channel extending therealong, the channel being internally stepped so that it has a relatively broad first part of its depth to fit over a relatively thick container wall and has a narrower second part to its depth, approaching the bottom of the channel, to more closely accommodate a narrower container wall.

2. An open-topped flat pack container as claimed in Claim 1, wherein the first channel part is approximately twice as broad as the second channel part so that it may accommodate a double thickness wall of the container while the second channel part accommodates relatively closely a single thickness wall of the container.

3. An open-topped flat pack container as claimed in Claim 1 or Claim 2 wherein the corner connector is formed so that the channel walls have a degree of resilience to slightly resiliently close toward each other to grip a container wall fitted therein.

4. An open-topped flat pack container as claimed in Claim 1,2 or 3, wherein one or more lug means are provided within the channel and preferably in the first part of the channel to grip the container wall.

5. An open-topped flat pack container as claimed in Claim 4 wherein the one or more lug means each slot into a corresponding slot formed in the the container wall.

6. An open-topped flat pack container as claimed in any preceding Claim,

wherein the arms of the connector comprise a pair of base plate portions subtending an angle therebetween corresponding to the angle of the corner, each base plate portion having a ledge projecting inwardly (i. e. towards the interior of the container) therefrom and which then extends as a retaining wall downwardly to define between it and the base plate portion a channel part having a first width and which then extends in a step inwardly again and then downwardly again to define a channel part of greater width than said first width channel part whereby the corner connector at each corner of the tray fits over the container side wall with the side wall extending into the first width part of the channel and over the container end wall with the end wall extending into the wider part of the channel.

7. A kit of parts for a flat pack open top container and which comprises a blank sheet of board material having a central base portion and flanking side wall portions and end wall portions that can be folded upwardly to form the walls of the container, each corner of the container being able to be held together in the assembled state by a respective corner connector, the kit having a plurality of corner connectors wherein each corner connector comprises a pair of arms, the arms subtending an angle therebetween corresponding to the angle of the corner, each arm having a channel extending therealong, the channel being internally stepped so that it has a relatively broad first part of its depth to fit over a relatively thick container wall and has a narrower second part to its depth, approaching the bottom of the channel, to more closely accommodate a narrower container wall.

8. A kit as claimed in Claim 7 wherein the kit further comprises a plurality of rails to fit over the top edge, in use, of the side and/or end walls of the container, respectively, and which will fit into the channel of the connectors.

9. A kit as claimed in Claim 8 wherein the rails are shaped to have a similar stepped profile to the corner connector channel to be able to fit closely to the corner connector whereby the rails are held firmly in place with no need for alternative

fastening means and whereby the rails for the side walls may be the same as the rails for the end walls.

10. A comer connector for use to hold together an edge wall and side wall of an open topped flat pack container, which corner connector comprises a pair of arms, the arms subtending an angle therebetween corresponding to the angle of the corner, each arm having a channel extending therealong, the channel being internally stepped so that it has a relatively broad first part of its depth to fit over a relatively thick container wall and has a narrower second part to its depth, approaching the bottom of the channel, to more closely accommodate a narrower container wall.

11. A corner connector as claimed in Claim 10 wherein the comer connector is provided with one or more lugs that project into the channel.

12. A corner connector as claimed in Claim 11, wherein the lugs project from the base plate into the wider part of the channel.