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. Nos. 4,194,772, 4,678,216, 5,129,537, 5,713,482, 7,243,962 and US2009/0294449 relate to such plastics securing rings.
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.
The present invention provides a securing ring for holding a lid or similar closure on a container, the securing ring comprising:
a ring end having a radially outer surface;
a latch lever having a latch lever end, and
a pivotable connection by which the latch lever end is mounted to the radially outer surface, the radially outer surface being recessed so as to at least partially accommodate the pivotable connection. Because the pivotable connection is at least partially accommodated in the recessed radially outer surface of the ring end, the overall radial height (radial size) of the lever and ring end assembly is reduced. The ring end and latch lever assembly may similarly form parts of a securing ring latch mechanism of reduced radial dimension.
The pivotable connection may comprise a pivot shaft receivable in a bearing recess, preferably as a snap fit for ease of assembly. The pivot shaft may be mounted to the latch lever end, for example by a centre web and by two end webs, one said end web being disposed respectively on either side of the centre web. This provides a robust mounting which is not significantly weakened by moulding knit lines.
The bearing recess may comprise at least one hook shaped formation upstanding from a depression which forms the recessed radially outer surface of the ring end. In this way, a snap-fit bearing for the pivot shaft is conveniently produced which is readily formed with an optimally low profile.
For strength and compactness, the latch lever may comprise a top wall and a pair of side walls which define a channel within which the ring end may be at least partially received when the lever is in a closed condition.
The ring may comprise a further ring end to which the lever is mounted by a further pivotable connection.
The ring end, further ring end and lever may form at least part of a latch mechanism having a radially inner portion of reduced axial external thickness so as to provide relief for stable stacking of a first container on top of a second container when the securing ring is attached to the second container.
The lever may comprise:
an elongate top wall which, with the lever in a closed position, lies radially outward of said ring end and extends generally circumferentially of the ring, and
a pair of opposed side walls, co-extensive with the top wall and lying axially to either side of said ring end, so as to form, together with the top wall, a channel in which said ring end is at least partially received.
With the lever in the closed position, a radially inner edge of at least one of the lever side walls preferably lies radially outward of the inner diameter of said ring end to define at least part of the radially inner portion of reduced axial external thickness.
The further ring end may comprise an opposed pair of further walls lying axially to either side of the ring and between which the lever is mounted by the further pivotable connection, and,
with the lever in the closed position, a radially inner edge of at least one of the further walls lies at least as far radially outward as the at least one lever side wall radially inner edge, to define at least part of the radially inner portion of reduced axial external thickness.
The securing ring may comprise a main part having a profile which is extended into said further ring end between said further side walls.
The further pivotable connection may comprise a further pivot shaft cantilevered from the further ring end. This provides a tough pivotable connection which may be easily assembled with the lever and which may be readily formed without weaknesses arising from moulding knit lines.
For compactness and ease of assembly, the further ring end may comprise a yoke from which the further pivot shaft is cantilevered.
The further pivot shaft may comprise an enlarged free end. This strengthens the pivot assembly and assists in retaining the further pivot shaft in its bearing by providing a mechanical key.
To further assist in reducing the radial dimension of the ring end and lever assembly, the radially outer surface of said ring end and/or the latch lever top wall may comprise one or more further recesses which accommodate a portion of the enlarged free end.
Some or all of the recess and further recess(es) may be blind-ended. In this way a continuous and, if desired, smooth, outer surface of the ring can be maintained. The continuous surface presents a neat appearance and is hygienic by minimising crevices where dirt and contaminants may accumulate.
The further pivot shaft may be slidable in a slot in one of the side walls of the lever. This eases assembly and can allow the ring to open or expand circumferentially to a greater extent than otherwise possible.
The ring end may comprise a tip having an radially outwardly projecting detent with an engagement surface facing circumferentially rearward of the ring end and the further ring end may comprise a radially inwardly projecting detent with an engagement surface facing circumferentially rearward of the further ring end, the engagement surfaces being mutually engageable for the transfer of hoop stress between the ring end and further ring end. Locating the outwardly projecting detent at the ring end tip reduces the overlap between the interengaged ring end and further ring end and thereby increases the angle through which the lever may be pivoted. This in turn increases the amount by which the ring may be expanded and contracted.
For additional security, the lever and ring end may comprise a snap-fit interlock which is engaged when the lever is in a closed position over the ring end, and which is manually disengaged as the lever is raised from the closed position by pivoting about said pivotable connection.
The snap-fit interlock may be positioned whereby, when the lever is closed, components of the interlock are accommodated between the pivotable connection and the further pivotable connection. This improves the mechanical advantage when manually disengaging the interlock as the lever is raised.
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 is an enlarged view of a portion of
A first embodiment of the present invention is shown in
The radially outer surface 22 of the top wall 23 extends into the securing ring end 14 and is recessed at 26 to partially accommodate a pivot shaft 28 mounted to one end of a latch lever 30 by a centre web 32 and a pair of end webs 34. The pivot shaft 28 is snap-fittable into a pair of bearing recesses 36 defined by a pair of hook shaped formations 38 upstanding from the outer surface recess 26. For clarity and simplicity, only one of the hook shaped formations 38 is shown in the half-sectional view of
In a modification, the recess 26 may extend all the way through the top wall 22a, to form a window in which the pivot shaft 28 is partially accommodated. However, the pivot shaft preferably does not intrude significantly into the groove 24, so as not to interfere with the securing ring's installation about a container and lid. It is preferred that at least a thin web of top wall material remains at the bottom of the recess 26, to better confine the pivot shaft 28 in the bearing recess 36 and to act a barrier against ingress of contaminants into the groove 24.
The discontinuity 12 defines a further ring end 16, which comprises a yoke 46 having a pair of opposed, generally parallel arms 48. Each arm 48 is a continuation of one of the ring side walls 18 and carries an inwardly extending cantilevered pivot shaft 50. The two pivot shafts 50 are co-axially opposed and each has a button-shaped, enlarged free end 52 (only one such end 52 being visible in
To further assist in reducing the radial profile of the overlapping ring ends 14, 16, the radially outer surface 22 of the ring end 14 preferably comprises two further recesses 60 which each accommodate a portion of one of the enlarged free ends 52 of the cantilevered pivot shafts 50.
The lever interior 44 is preferably further provided with a transverse web 64, to which the centre web 32 is also attached. With the lever 30 in its closed position, a forward surface of the web 64, lying closest to the pivot shaft 28, rests against a pair of pegs 66. These pegs are integrally moulded with the ring end 14 to stand up from the top wall radially outer surface 22. Contact between the pegs 66 and the transverse web 64 transmits tensile hoop stress in the ring end 14 into the lever 30 as compressive stress, thereby sharing and partially relieving the stress burden on the pivotable connection 28/36. The transverse web 66, together with further lever interior walls 65 also help to confine and constrain the button-shaped enlarged ends 52 of the further pivot shafts 50, thereby strengthening the pivotable connection 50/58 when the pivot shafts 50 are engaged with the bearing surfaces 58.
Similarly, the hook shaped formations 38 preferably each comprise a hind portion 68 extending towards the tip 70 of the ring end 14. The top wall 23 of the ring 10 extends forwardly between the arms 48 of the yoke 46 to form a web portion 72 which overlies the hook shaped formations 38 when the ring end 14 and further ring end 16 are brought together. A further web portion 74 depends from the web portion 72 and is attached between the web portion 72 and the ring side walls 18/yoke arms 48. The further web portion 74 engages in complementary slots formed in the hind portions 68 of the hook shaped formations 38 when the ring ends 14, 16 are brought together (see
A pair of ears 76 is integrally moulded with the ring end 14 so as to protrude radially from the ring top wall 23 into the interior space 44 when the lever 30 is in its closed position. In that position, axially aligned through holes 78 in the ears 76 also align with the slots 54 for reception of a security tag, tamper indicating lock pin, or the like. Thus the lever 30 cannot be moved to its open position without removing or breaking the tag etc.
A second embodiment of the invention is shown in
The section plane of
Comparing with
Adopting the design features shown in
Moving the hook shaped formations closer to the tip 70 of the ring end 14 as in
The extra distance between the pivotable connections 28/36 and 50/58, due to the ring curvature, also maintains the overcentre action of the lever mechanism, despite the decreased lever radial projection. The lever mechanism will therefore remain stably closed (i.e. hold the ring ends together in a circumferentially contracted state) even without the assistance of the snap fit interlock features 82/88.
Referring to
Number | Date | Country | Kind |
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61600443 | Feb 2012 | US | national |
61661282 | Jun 2012 | US | national |
61661296 | Jun 2012 | US | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2013/053131 | 2/15/2013 | WO | 00 |