This invention concerns a latched securing ring for holding a lid or similar closure on a container, the ring for example being of the kind having an inwardly facing, circumferentially extending groove arranged to trap a rim of the lid/closure and also trap a peripheral flange or similar radial extension(s) provided around an opening in the container. In this way the lid rim and container flange are locked together.
Where the ring is re-useable, it is typically openable to allow installation over or removal from the flange and rim. Then the ring will usually comprise a circumferential discontinuity which forms a pair of overlappable or opposed ends which are releasably secured together by a latch mechanism. The groove profile will often be tapered, to draw the flange and rim into engagement with each other as the ring is tightened, and optionally to draw the flange and rim into clamping engagement with an interposed sealing gasket. However such clamping and/or sealing functions need not always be present. Optionally, the ring latch mechanism may be provided with an anti-tamper lock pin or similar tamper indicating security seal or tag, to provide some guarantee of the integrity of the container contents. The container and its opening may be of various sizes and shapes, with lids or other closures of a suitable corresponding size and shape. For example the opening and lid may be substantially square, rectangular or other polygonal shape. Typically the lid or closure is round, for fitment to an open-ended cylindrical drum. In the North American market, fibreboard drums with steel end chimes are commonly used together with injection moulded lids. Open-topped blow-moulded plastics drums are also used, again with injection moulded plastics lids. The blow moulded drums predominate in other markets.
Historically the openable securing rings have been made from metal, commonly painted or plated steel. However these are difficult to recycle and are prone to corrosion, or to flaking of the coating. Corrosion or coating particles shed by the ring can contaminate the container contents. There is therefore an increasing use of securing rings made from plastics. U.S. Pat. No. 4,194,772, U.S. Pat. No. 4,678,216, U.S. Pat. No. 5,129,537, U.S. Pat. No. 5,713,482, U.S. Pat. No. 7,243,962 and US2009/0294449 relate to such plastics securing rings. US2006/022395 to Kuzelka discloses a locking belt used to secure a removable lid on a drum. The belt is formed from plastics and comprises a first end to which an arcuate handle is secured by an elongate flexible strap. Together the handle and strap form parts of a latch mechanism which can be used to draw a second end of the belt into overlapping interengagement with the first end. When the latch mechanism is closed, the handle overlies a portion of the belt remote from the interengaged belt ends. In this general layout, Kuzelka's latch mechanism therefore resembles many three-part latched metal securing rings of the prior art. The flexible strap however extends radially outwardly across the interengaged ends when the lever is in the closed position. It then also overlies a pivotable connection, by which the lever is mounted to the belt rearwardly of the second end. This latch mechanism is therefore quite extensive, both radially and circumferentially of the belt. In a conventional three-part metal latch mechanism, the equivalent component to the flexible strap is generally a wire loop which is more compact than the strap, and is able to lie to either side of (rather than radially overlying) the interengaged ring ends and the lever pivot in the closed position, to provide an overcentre, stably closed latch condition. A separate hook, snap-engageable in an aperture formed in the handle, is required in order to secure Kuzelka's handle in its closed position.
To be strong enough to survive normal rough handling of the filled containers, plastics securing rings need to be made with a heavier (thicker) cross-section than a corresponding metal ring. Similarly, the latch mechanism for the openable ring ends tends to be significantly bulkier in a plastics ring compared to a metal ring. This can lead to a number of problems. One group of problems arises when the bulkier latch protrudes radially from the container to a significant degree. This limits the relative orientations in which the containers can be packed closely together side by side during transport or storage. Drums are also often moved short distances by turning them on their side and rolling them, e.g. to move them along the length of a truck trailer during loading and unloading. A highly protruding latch is not only prone to mechanical damage, but will also prevent the drum from rolling in a straight line. Some existing plastics latch designs protrude to an extent which prevents the containers from being rolled along the length of a typical truck trailer without running into, or falling off, the trailer sides. A latch which protrudes excessively in the ring axial direction can also interfere with stable stacking of containers one upon the other, and is prone to axial crushing as a result of such stacking and interference. There is therefore a need to provide a securing ring latch capable of being moulded from plastics material, which is of compact design and yet which is able to withstand the rigours of rough treatment to be expected in normal use.
The present invention provides a securing ring for holding a lid or similar closure on a container, the securing ring comprising:
a first end;
a second end;
a latch lever movable between an open position in which the first and second ends are separated and a closed position in which the first and second ends are drawn closer together, and
a flexible connection by which the latch lever is connected to the first end;
the latch lever being at least partially overlappingly received against the first end in the closed position.
The securing ring is therefore able to be formed from plastics or similar mouldable materials, with the flexible connection allowing the latch lever to be formed together with the remainder of the ring as a single piece. At the same time, the overlapping configuration of the latch lever and the first end of the ring can be made compact, despite the heavier sections necessary in securing rings made from plastics as compared to those formed from metal.
The flexible connection may take various forms. For example, the flexible connection may comprise a so-called “living hinge”, i.e. a flexure bearing formed from the same material as, and continuous with, the first end of the ring and the latch lever. The living hinge preferably comprises a short span, flexible web extending along the hinge axis and spanning between the first end of the ring and the latch lever. Such a living hinge may be readily and cheaply formed together with the latch lever and remainder of the ring in a single moulding operation. By suitable design and choice of materials well known to those skilled in the art, a living hinge can operate over many thousands of cycles without fatigue failure, and provides a compact, low profile, low friction, no wear, flexible connection between the latch lever and ring first end. Alternatively, the flexible connection may comprise at least one flexible strap. For example the flexible strap may comprise a ligament integrally moulded so as to be of the same material as, and continuous with, the first end of the ring and the latch lever. Alternatively, the flexible strap may comprise a ligament insert moulded so as to interconnect the first end of the ring and the latch lever.
The flexible connection may be provided at a distal end of a circumferential extension of the first end of the ring. For example, the ring may comprise a radially outer wall and a pair of side walls which define between them a radially inwardly open, circumferential groove. The circumferential extension may form a continuation of the radially outer wall at the first end of the ring. Alternatively, the circumferential extension may form a continuation of the pair of side walls at the first end of the ring. By making the securing ring and latch lever as a single piece, manufacturing costs can be reduced in comparison to those for a two-piece lockband. Secondary capital is reduced for the tooling or processing for a separate latch lever. Direct labour costs are reduced by eliminating the post-moulding assembly operation of mounting the latch lever to the ring first end. The number of overlapping layers in the region of the latch lever when in its closed position may also be minimised, thereby reducing the bulk of the securing ring latch mechanism, in the ring radial direction, and/or in the ring axial direction.
Preferably the flexible connection allows angular movement of the latch lever through at least 120 degrees, more preferably at least 140 degrees, with respect to the first end. This results in a correspondingly greater range of expansion of the securing ring as the latch lever is moved towards the open position, allowing the securing ring to be more easily installed or removed from around a container opening and container lid, in comparison to a more restricted range of angular movement of the lever, e.g. of 90 degrees or less.
The latch lever may be pivotally connected to the second end of the ring, for example by a pivot connection comprising a pivot shaft rotationally received in a pivot bearing. The pivot bearing may comprise a hook-shaped formation formed on a radially outer surface of the second end of the ring. Advantageously, with the lever in the closed position, the pivotal connection between the latch lever and the second end of the ring lies radially outwardly of the flexible connection, whereby the line of action of hoop stress induced tensile force in the flexible connection extends radially inward of the pivotal connection, and the latch lever operates with an overcentre action.
Alternatively, the latch lever may be pivotally connected to the second end of the ring by any other suitable form of pivotable connection, for example by a knife-edge bearing or a curled lip receivable in a curved slot.
The above and other preferred features and advantages of the invention are further described below with reference to illustrative embodiments of the invention shown in the drawings.
a and 2b correspond to
a and 14b are scrap views showing a portion of
a is a scrap view showing an alternative form of latch lever end, and
Referring initially to
As best seen in
As shown in
The side walls 50 of the latch lever 44 extend at 51 forwardly of the living hinge towards the very tip of the ring second end 42 when the latch lever is in the closed position. A pivot shaft 52 (whose end position is indicated schematically in dotted lines in
As best seen in
Compared to the living hinge 46, the ring first end extension 54 is relatively stiff and will maintain its curvature even under quite substantial tensile loads. This curvature also ensures that the pivotal connection between the latch lever and the second end of the ring (in this case formed by the pivot shaft 52 and bearing surface 64) lies radially outwardly of the flexible connection (in this case the living hinge), whereby the line of action of hoop stress induced tensile force in the flexible connection extends radially inward of the pivotal connection. That is, the line of action of the tensile force transmitted through the living hinge 46 passes radially inwardly of the axis of the pivot shaft 52. The latch lever 44 therefore operates with an overcentre action and will remain stably in the closed position under ring tensile hoop stress imposed loading. No additional measures are required to hold the latch lever 44 in its nested position over the second ring end 42. However an eye 70 may be provided on the ring second end 42 radially outer surface 20 and apertures 72 may be provided in the lever side walls 50. The eye 70 and apertures 72 are brought into registration when the lever is in its closed position, for reception of a tamper indicating security pin, security tag or the like (not shown), in a manner familiar to those skilled in the art. For stress transfer directly between the interengaged ring ends 40, 42, a transverse wall 80 is provided, upstanding radially from the very tip of the second ring end 42, and engageable behind a radially depending web 82 which spans between the side walls 22, 24 inside the first ring end 20.
The latch mechanism shown in
The latch lever side wall extensions 51 are linked by a radially outer web 53 which is a continuation of the latch lever top wall 48 beneath the living hinge 46, and lies directly underneath the first ring end extension 54 when the latch mechanism 32 is closed. The web 53 terminates in an upwardly curled lip 55 (see
For hoop stress transmission from the first ring end 40 directly to the second ring end 42 when the latch mechanism is closed (thereby relieving stress on the other latch mechanism components, such as the latch lever 44, first ring end extension 54 and pivot connection 55/57), the top wall 20 of the ring first end 40 is provided with a post 65 which depends into the channel 18 through the ring first end 40. The post 65 has a cruciform slot which divides its distal end into four resilient legs, each with a radially protruding foot, which are snap-fittable through an aperture 67 formed in the outer wall 20 of the ring second end 42 as the two ring ends 40, 42 are levered into close proximity by the latch lever 44. The ring outer wall is preferably countersunk for reception of the feet on the post 65, so that these feet do not protrude into the ring groove 18 where they might interfere with the lid rim, container end flange or like components secured by the ring 10. See in particular
In the latch mechanism 32 shown in
As best shown in
In a variant (not shown), the end of the latch lever containing the notches 68 is shortened so as to terminate short of or adjacent to the ring first end 40 when the latch lever 44 is in its closed position. In this way the maximum number of overlapping layers in the closed latch mechanism is reduced from three to two; the ring second end 42 being received directly in the ring first end 40 without any intervening latch lever layer. The post 65 may therefore engage directly with the aperture 67, without passing through the latch lever 44. To match the shortened latch lever 44, the trunnions 66 are moved further back from the tip of the ring second end 42, so that the ring second end 42 projects from the channel-shaped latch lever 44 and is received within the channel-shaped ring first end 40 when the latch lever 44 is in the closed position. The end of the top wall 48 of the latch lever 44 adjacent to the notches 68 may be relieved at 49 (see
In
The invention is not limited to the embodiments described above and may be carried into effect within the scope of the claims in many other ways. Any individual element or feature of any of the embodiments described above may be combined with or substituted for any other suitable element or feature of any other described embodiment.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2013/053130 | 2/15/2013 | WO | 00 |
Number | Date | Country | |
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61600443 | Feb 2012 | US | |
61661282 | Jun 2012 | US | |
61661296 | Jun 2012 | US |