A WALL COUPLING

Abstract: A wall coupling restrains adjacent walls 2 and 3 from displacement over each other. The two walls have co-­ incident apertures 12 and 16. A flexible moulded plastics retaining strip 5 is carried by the wall 2 on its side remote from the wall 3. The strip 5 overlies the aperture 12 and has an end 8 which is secured relative to the wall 2 and an end 7 which is slidable along tracks on the wall 2 in a direction towards and from the end 8. A mid-length region 6 of the strip 5 between its ends 7 and 8 has integral hinges 13 to 15 so that during displacement of the strip end 7 towards the end 8, the region 6 doubles to project through the apertures 12 and 16 and thereby couple the walls 2 and 3 to restrain them from relative displacement. Stop/catch means can be provided to temporarily retain the strip end 7 in a position where the mid-length region 6 of the strip is in either a folded or an unfolded condition. The invention is suitable for coupling a container lid which carries the retaining strip 5 to a wall of a container body.

Description: TECHNICAL FIELD & BACKGROUND ART The present invention relates to a wall coupling and is particularly concerned with such a coupling which restrains two adjacent wall parts in overlying relationship from relative displacement over each other. Typically one wall part may be on a container lid while the other wall part is on the container body so that the coupling provides a means for retaining the lid in its closed condition. Alternatively one wall part may be coupled merely to form an extension of a component (such as a lid) having the other wall part. Numerous devices have been proposed for coupling together wall parts as aforementioned such as latches, strapping, removable pegs and snap engaging lock devices. An example of such a device is disclosed in the Specification of DE-U-8704686. This latter disclosure, which forms the basis of the preamble to claim 1 herein, is for a spring clip having generally parallel legs which are displaceable relatively towards and away from each other. The legs extend through co-inciding openings in two overlying wall parts and the clip is spring biased to urge flanges and barbs on the legs to engage over the wall parts to retain them together; by displacing the legs together against the spring biasing, the barbs can be disengaged to release the wall parts from each other. It is often considered that known devices are relatively expensive to manufacture and/or assemble, are inconvenient to operate (either or both for coupling or uncoupling of the wall parts), that they form a relatively obtrusive part or projection on the wall parts (either when those parts are uncoupled or coupled together) or that they have a means of coupling that may be mislaid. It is an object of the present invention to provide a wall coupling which is relatively simple and inexpensive to manufacture and assemble, is easy and convenient to operate, that may form a relatively unobtrusive feature of a wall part, and which is unlikely to be accidentally damaged or mislaid. STATEMENT OF INVENTION & ADVANTAGES According to the present invention there is provided a wall coupling comprising a first wall part having a first opening and which is to be positioned adjacent to a second wall part having a second opening with the first and second openings co-inciding; a retaining strip carried by the first wall part on the side thereof which is, or is to be, remote from the second wall part, said retaining strip overlying the first opening and having opposite end regions mounted to be displaceable relatively towards and away from each other and a mid-length region which is foldable and unfoldable respectively in response to said relative displacement of the end regions whereby, during displacement of the end regions relatively towards each other on the first wall part, the mid-length region is folded to, or towards, a doubled condition in which it extends through the first opening for entering the second opening to couple the two wall parts and to restrain them from displacement over each other. Further according to the present invention there is provided an assembly of a component having a wall coupling as specified in the immediately preceding paragraph and a further component having a second wall part which is, or is intended to be, coupled to the first wall part by the retaining strip. By the present invention it is envisaged that the retaining strip will be carried by the first wall part so that its end regions are displaceable towards each other in a sense whereby the mid-length region of the strip is folded to project through the opening in the first wall part and into a coincident opening of the second wall part which is positioned adjacent and conveniently (but not essentially) in face-to-face contact with the first wall part. Desirably the folded strip is a relatively close fit in both the first and second openings to alleviate relative displacement between the two wall parts. By way of example, the first wall part may be on a closure member such as a lid or similar component which is to be coupled to a second wall part of a container body (or of an extension to the closure member). With this in mind the second wall part will have the second opening appropriately located to coincide with the first opening and to receive the folded retaining strip when the coupling is effected. The first opening will usually be in the form of a slotted aperture in the first wall part. The second opening may also be in the form of an aperture which extends through the second wall part or may be in the form of a recess in the second wall part within which recess the folded retaining strip is received. Where the second opening is an aperture in the second wall part it is possible for the folded retaining strip to extend through both the first and second openings to be received in a co-inciding third opening in a third wall part which third wall part is fixed relative to (conveniently being integral with) the first wall part. By this latter proposal the second wall part may be received between the first and third wall parts and coupled thereto by the folded retaining strip. With such an arrangement the folded retaining strip is not cantilevered in its coupling between the second wall part and the third wall part and thereby the retaining strip is relieved of shear forces to which it may be subjected from its coupling to the second wall part. Preferably the relative displacement between the end regions of the retaining strip is in a plane which is parallel and adjacent to the first wall part. The aforementioned displacement may be along track means on the first wall part. The track means conveniently retains the retaining strip on the first wall part substantially unobtrusively when the retaining strip is in its unfolded condition and substantially unobtrusively on the side of the first wall part from which the folded retaining strip enters the first opening. It is not necessary for both end regions of the retaining strip to be displaceable on the first wall part. Usually one end region will be secured relative to the first wall part while the other end region is slidably displaceable (conveniently along the track means as aforementioned) relative to the first wall part to effect the folding and unfolding of the mid-length region of the retaining strip. For convenience of displacing an end region of the retaining strip, such end region may have a handle or a finger/thumb recess, ridge or the like which is intended to facilitate its manual engagement. To alleviate inadvertent unfolding of the retaining strip it is preferred that stop/catch means is provided for temporarily retaining the strip in its folded condition. Stop/catch means may also be provided for temporarily retaining the strip in its unfolded condition (for example to alleviate the mid-length region of the retaining strip from inadvertently passing through the first opening where it could possibly interfere with the location of the second wall part adjacent to the first wall part). The stop/catch means conveniently comprises co-operating recesses or dimples and complementary projections which inter-engage between the strip and first wall part to provide interference which temporarily restrains the strip from sliding displacement along the aforementioned track means. The retaining strip may be provided with one or more hinge regions which facilitate the folding and unfolding of the strip and may determine the locations on the strip at which folding is to be effected. Generally three such locations will be provided, one location being within the mid-length region of the strip and the other two locations being one at each end of the mid-length region between that mid-length region and the adjacent end region of the strip. The hinge regions may serve to determine the direction in which the mid-length region is displaced when the end regions of the strip are moved relatively towards each other (to ensure that as the mid-length region is folded to, or towards the doubled condition, a folded portion of the strip will pass through the first opening). Conveniently the hinge regions are formed integral with the retaining strip, for example by relatively thin walled sections of the retaining strip. The retaining strip will usually be formed as a one piece plastics moulding. It is envisaged that the first wall part and the component of which it forms part will also be formed as a plastics moulding to which the retaining strip is fitted. Although the second wall part and such component of which that wall part forms part may also be of plastics, it is envisaged that this wall part is likely to be of any material such as cardboard or metal sheet. It will be appreciated that a component may have several wall couplings in accordance with the present invention for coupling that component to one or more second wall parts. DRAWINGS One embodiment of a component having a wall coupling constructed in accordance with the present invention and an assembly of such component with a second wall part will now be described, by way of example only, with reference to the accompanying illustrative drawings in which:- Figure 1 is a side elevation of a wall part of the component and shows the retaining strip; Figure 2 is a section on the line II - II of Figure 1; Figure 3 shows the retaining strip incorporated in the wall coupling; Figure 4 is a section on the line IV - IV of the wall coupling in Figure 1 with the wall part positioned adjacent to the second wall part for coupling thereto; Figure 5 is a similar section to that shown in Figure 4 and illustrates an assembly of the two wall parts coupled together by the retaining strip; Figure 6 is a perspective view of the coupling shown in Figure 5, and Figure 7 shows, in part section, a modification to the wall coupling. DETAILED DESCRIPTION OF DRAWINGS For convenience, the present example will be considered for coupling a closure member in the form of a plastics moulded lid 1 having a peripheral skirt 2 to a container body (or to an extension skirt for the lid) provided by a wall 3 which is received within a boundary presented by the skirt 2 and substantially in face-to-face contact therewith. The wall 3 will often be of plastics although it will be appreciated that other materials will be suitable for that wall. Integrally moulded with the exterior of the skirt 2 are external ribs within which are formed opposed parallel tracks 4 (see Figures 1 and 2). A retaining strip 5 is captured between the tracks 4. The strip 5 comprises a longitudinally extending mid-length region 6 and opposed end regions 7 and 8. The retaining strip 5 is formed as a one piece injection moulding in plastics. Conveniently the end region 7 is of circular profile with the longitudinal extent of the strip region 6 extending radially therefrom. The end region 8 is in the form of a bar extending perpendicularly relative to the longitudinal extent of the strip region 6. The circular end region 7 has diametrically opposed external flanges 9 while the opposite ends of the bar region 8 are profiled as flanges 10. The tracks 4 are in the form of longitudinally extending recesses and the flanges 9 and 10 are received within the opposed recesses 4 (as shown in Figure 2) to retain the strip 5 on the skirt wall part 2. The tracks 4 are parallel with the longitudinal extent of the strip mid-length region 6 and the end region bar 8 abuts an external rib 11 at an end of the tracks 4. The flanges 9 are received in the recesses 4 to be slidable along the tracks. The end bar 8 is welded, adhesively secured or otherwise bonded to firmly retain it adjacent to the rib 11. Alternatively the end bar 8 may be mechanically retained, for example by snap engagement or an interference fit, in the position shown in Figure 1 adjacent to the rib 11. Formed through the wall thickness of the skirt 2 is an elongated or slotted aperture 12 the longitudinal extent of which is parallel with that of the mid-length region 6 of the retaining strip. The strip 5 generally overlies the aperture 12 as shown in Figure 1. The plastics retaining strip 5 is moulded with relatively thin wall portions which provide three integral and longitudinally spaced hinge regions 13, 14 and 15. Hinge region 13 is located generally at the centre length position of the mid-length region 6, the hinge region 14 is located between the end region 7 and the centre length region 6 and the hinge region 15 is located between the end region 8 and the mid-length region 6. The circular end region 7 is displaceable longitudinally towards and from the end region 8 by sliding movement of the flanges 9 along the tracks 4 and in a plane which is adjacent to and substantially parallel with the skirt wall 2. Conveniently the circular region 7 is provided with a concentric annular flange 7a to facilitate engagement of that region with thumb or finger for its manual displacement along the tracks 4. The plastics of the retaining strip 6 is flexible so that, in response to displacement of the end region 7 in a direction towards the end region 8, the strip folds at the hinge regions 13 to 15 from what may be regarded as an unfolded condition (shown in Figure 4) to a folded condition shown in Figure 5 where the mid-length region 6 is doubled and projects through the aperture 12 of the wall 2. It will be noted from Figures 4 and 5 that the reduced wall thickness which forms the hinge regions 13 to 15 of the plastics retaining strip is offset towards one or the opposite broad faces of the mid-length region 6 as appropriate to ensure that the displacement exhibited by the retaining strip in moving from its unfolded to its folded condition is in the required direction for the doubled mid-length region to project through the aperture 12. It will also be noted that in its folded condition the mid-length region 6 of the retaining strip is received closely between the opposed side edges of the elongated aperture 12 so that those side edges can restrain the folded mid-length region of the retaining strip from substantial lateral displacement. The wall 3 is provided with an elongated aperture or slot 16 which is arranged to coincide with the slot 12 when the walls 2 and 3 are in the position at which they are required to be coupled (for example with the lid 1 correctly fitted to close the container body). In this latter position it will be apparent that the folding of the mid-length region 6 of the retaining strip from the condition shown in Figure 4 to that shown in Figures 5 and 6 will cause the retaining strip to project through both apertures 12 and 16. Similarly to the slot 12, the folded region 6 is closely received between the laterally opposed side edges of the slot 16 so that the wall 2 is restrained from displacement relative to the wall 3 in a direction which extends perpendicularly to the plane of the drawing in Figure 5. It will, of course, be appreciated that relative displacement between the walls 2 and 3 in the plane of the drawing in Figure 5 may be restrained by appropriately reducing the longitudinal extent of the slots 12 and 16 (so that in its doubled condition the mid-length region 6 of the retaining strip is received as a relatively close fit within the two apertures both in the plane of the drawing in Figure 5 and in the plane perpendicular thereto). It is likely that the plastics of the retaining strip will have a resilient nature or memory with a tendency for the strip to revert from its folded condition of Figure 5 to its relatively unfolded condition of Figure 4. To alleviate this and also to alleviate the likelihood of the retaining strip being inadvertently displaced from its folded to its unfolded condition, it is preferred that a stop 17A is provided on each of the tracks 4 with which the flanges 9 can engage when the end region 7 is displaced to fold/double the mid-length region 6. The stops 17A conveniently comprise studs or recesses on the track which snap engage or otherwise interfere or catch with complementary recesses or studs respectively on the flanges 9. Similar stops 17 can be provided on the tracks 4 with which the flanges 9 can engage when the mid-length region of the strip is in its unfolded condition shown in Figure 4; this is to alleviate the likelihood of the retaining strip 6 projecting through the aperture 12 prior to the wall 3 being positioned adjacent to the skirt wall 2 and thereby the retaining strip from interfering with the positioning of the wall 3. The flanges 9 will, of course, be readily disengageable from either the stops 17A or the stops 17 by manual pressure applied to displace the end region 7 along the tracks 4. In the modification shown in Figure 7 the lid 1 is provided with an internal flange 18 which extends substantially parallel to and spaced from the skirt wall 2. The flange 18 has an elongated aperture 19 which coincides with the aperture 12 in the wall 2 and may be similarly sized. The wall 3 is positioned between the wall 2 and flange 18 so that its aperture 16 coincides with the apertures 12 and 19. When the end region 7 is displaced towards the end region 8 for the mid-length region 6 of the retaining strip to be folded, the doubled retaining strip projects through the three apertures 12, 16 and 19 and may be closely received therein. Consequently the wall 3 is captured between the walls 2 and 18 to which it is coupled by the retaining strip while such shear forces to which the retaining strip may be subjected from the wall 3 are supported by both the flange 18 and wall 2 (unlike the cantilevered support for the doubled retaining strip shown in Figure 6).

Claims: A wall coupling comprising a first wall part (2) having a first opening (12) and which is to be positioned adjacent to a second wall part (3) having a second opening (16) with the first and second openings co-inciding; a retaining strip (5) carried by the first wall part (2) on the side thereof which is, or is to be, remote from the second wall part (3), said retaining strip overlying the first opening (12) and having opposite end regions (7, 8) mounted to be displaceable relatively towards and away from each other and a mid-length region (6) which is foldable and unfoldable respectively in response to said relative displacement between the end regions (7, 8) CHARACTERISED IN THAT during displacement of the end regions (7, 8) relatively towards each other on the first wall part (2), the mid-length region (6) is folded to, or towards, a doubled condition in which it extends through the first opening (12) for entering the second opening (16) to couple the two wall parts (2, 3) and restrain them from displacement over each other. A coupling as claimed in claim 1 in which at least one end region (7) of the retaining strip (5) is displaceable along track means (4) on the first wall part (2). A coupling as claimed in either claim 1 or claim 2 in which one end region (8) of the retaining strip (5) is secured relative to the first wall part (2). A coupling as claimed in any one of the preceding claims in which said relative displacement between the end regions (7, 8) of the retaining strip (5) is in a plane substantially parallel with and adjacent to the first wall part (2). A coupling as claimed in any one of the preceding claims and comprising stop/catch means (17A) for temporarily retaining the retaining strip (5) in its folded condition. A coupling as claimed in any one of the preceding claims and comprising stop/catch means (17) or further stop/catch means (17) for temporarily retaining the retaining strip (5) in its unfolded condition. A coupling as claimed in either claim 5 or claim 6 in which the stop/catch means (17) or further stop/catch means (17A) comprises a recess and a projection which co-operate and provide interference which restrains relative displacement between the retaining strip (5) and the first wall part (2). A coupling as claimed in any one of the preceding claims in which the retaining strip (5) comprises at least one hinge region (13, 14, 15) which facilitates the folding and unfolding of the strip and determines at least one location on the strip (5) at which folding is to be effected. A coupling as claimed in any one of the preceding claims in which the retaining strip (5) comprises the, or at least one, hinge region (13, 14, 15) which determines the direction in which the mid-length region (6) of the strip is displaced when the end regions (7, 8) of the strip are moved relatively towards each other. A coupling as claimed in either claim 8 or claim 9 in which the retaining strip (5) has three hinge regions (13, 14, 15), one hinge region (13) being located within the mid-length region (6) of the strip and the other two hinge regions (14, 15) being located one at each end of the midlength region (6) of the strip between that mid-length region (6) and the adjacent end region (7, 8) of the strip. A coupling as claimed in any one of claims 8 to 10 in which the or a hinge region (13, 14, 15) is formed integral with the retaining strip (5). A coupling as claimed in claim 11 in which the hinge region (13, 14, 15) is formed by a relatively thin walled section of the retaining strip (5). A coupling as claimed in any one of the preceding claims in which the retaining strip (5) is formed as a one piece plastics moulding. A coupling as claimed in any one of the preceding claims and comprising a third wall part (18) which is secured relative to the first wall part (2) and is spaced therefrom, the third wall part (18) having a third opening (19) which co-incides with the first opening (12) in the first wall part (2), said first and third wall parts (2, 18) being arranged so that the second wall part (3) can be received between the first and third wall parts (2, 18) and coupled thereto by the retaining strip (5) when in its folded condition which extends through both the first and second openings (12, 16) to be received within the third opening (19). An assembly of a component (1) having a wall coupling as claimed in any one of the preceding claims and a further component having a second wall part (3) which is, or is intended to be, coupled to the first wall part by the retaining strip (5). An assembly as claimed in claim 15 in which the first said component comprises a closure member (1) and the first wall part is provided by a skirt (2) of the closure member and the further component comprises a container body to which the closure member (1) is to be fitted or an extension wall to the closure member (1). An assembly as claimed in claim 16 when appendant to claim 14 in which the third wall part (18) comprises an internal flange of the closure member (1) which internal flange is substantially parallel to and spaced from the skirt (2).

Inventors: WILLIAMS, DAVID ARTHUR
Applicants: LIN PAC MOULDINGS LIMITED
Application year: 1989
Main classification: B65D43
IPC codes: B65D43