Patent Publication Number: US-6712233-B2

Title: Lid with hinge for plastic pail

Description:
FIELD OF THE INVENTION 
     The present invention relates to a lid for a pail, and especially to a lid for a plastic pail. In particular, the present invention relates to a lid with an integral hinge, and to a pail with such a lid. The lid forms part of the pail and remains attached to the pail after opening. In embodiments, the lid may be placed on the pail in a variety of orientations i.e. the lid does not need to be placed on the pail in a specific orientation. 
     The expression “pail” has been used herein to include containers. The pails may have a variety of sizes, for example sizes in the range of from about 1 L to about 25 L. 
     BACKGROUND TO THE INVENTION 
     Plastic pails are used in the packaging and transportation of a wide variety of materials, including foodstuffs, paints, chemicals, granular materials, dyes and the like. The pails are filled with the material and a lid is placed on the pail for transportation and sale, and retained there until opened for use. At the time of use, the lid of the pail is removed and must be placed somewhere while all or some of the contents of the pail are removed. Typically, the lid is placed on the floor near the pail, or on a near object. The lid, once removed, tends to become misplaced, contaminated, or even cause storage problems. Consequently, the lid may become a tripping hazard and/or be susceptible to contamination by dirt or other materials. If only some of the contents of the pail are removed, the dirty lid contaminates the remaining contents of the pail. 
     In some instances, the pails are of a construction that exhibits evidence of access to the contents of the pail, whether the access is intentional opening of the pail or tampering with the contents of the pail. Such pails are known as tamper-evident pails. These pails are constructed so that removal of the lid requires that a section of the pail be broken in order to remove the lid. This provides physical evidence to the consumer of the opening of or tampering with the pail. 
     Canadian Patent No. 2,019,225 describes a tamper-evident lid and container (pail) combination that shows physical evidence if the lid is removed. In particular, the lid has a peripheral skirt interconnected to a flange peripherally extending from the container to the lower edge of the skirt. The connections of the flange to the skirt are weak and, as such, break when the lid is removed. This provides evidence of opening of the pail. 
     Some containers have hinged lids to overcome these problems. For instance, a hinged lid is described in Japanese Patents Nos. 2000142758 and 2000142762. These patents describe a container having an outer lid with a coupling strap connected to both the lid and container, 
     Lids, and pails with lids, that are not potential tripping hazards and which are less susceptible to contamination would be desirable. It is preferred that such lids also have tamper-evident characteristics, without reducing the effectiveness of the lid for subsequent use. 
     It would also be an advantage to provide a hinged lid that would be less bulky than the coupling strap described in the above Japanese patents, especially with respect to storage and shipping of pails and lids prior to filling. 
     SUMMARY OF THE INVENTION 
     A hinged lid, and a pail having a hinged lid, have now been found, in which the hinge is incorporated into the lid, preferably showing evidence of tampering. 
     Accordingly, one aspect of the present invention provides a plastic lid for a pail having a peripheral rim, said lid having a substantially planar central section integrally formed with a peripheral channel section, said channel section adapted to fit over the rim of the pail to effect closure of the pail, 
     said channel section comprising an edge section that extends exterior to the pail around the periphery of said lid, one section of the edge section forming a hinge section and the remainder of said edge section having a first section, a second section and a third section, each of said first, second and third section extending peripherally around the edge section of the lid, said second section being intermediate said first and third sections and integrally formed with said first and third sections, said second section being tearable from the first and third sections, 
     said hinge section being integral with said first section and having a portion of reduced thickness juxtaposed to said rim, 
     said central section, channel and first section of the lid being rotatable about said portion of reduced thickness after tearing of said second section from said first and third sections, thereby to effect opening of the lid. 
     Another aspect of the present invention provides a plastic lid for a pail having a peripheral rim, said lid comprising an edge section that fits over said rim, a portion of said edge section being a hinge integrally moulded therein and forming part of said lid, said portion of the edge section other than said hinge having a removable tamper-evident tear strip, said lid being openable by rotation about said hinge after removal of the tear strip. 
     A further aspect of the present invention provides a pail and lid, said pail having a peripheral rim, said lid having a substantially planar central section integrally formed with a peripheral channel section, said channel section adapted to fit over the rim of the pail to effect closure of the pail, 
     said channel section of the lid comprising an edge section that extends exterior to the pail around the periphery of said lid, one section of the edge section forming a hinge section and the remainder of said edge section having a first section, a second section and a third section, each of said first, second and third section extending peripherally around the edge section of the lid, said second section being intermediate said first and third sections and integrally formed with said first and third sections, said second section being tearable from the first and third sections, 
     said hinge section being integral with said first section and having a portion of reduced thickness juxtaposed to said rim, 
     said central section, channel and first section of the lid being rotatable about said portion of reduced thickness after tearing of said second section from said first and third sections, thereby to effect opening of the lid. 
     In another aspect, the present invention provides a plastic lid for a pail having a peripheral rim, said lid having a substantially planar central section integrally formed with a peripheral channel section, said channel section adapted to fit over the rim of the pail to effect closure of the pail, 
     said channel section comprising an edge section that extends exterior to the pail around the periphery of said lid, one section of the edge section forming a hinge section and the remainder of said edge section having a first section and a second section, each of said first and second section extending peripherally around the edge section of the lid, said second section being distal to the periphery and integrally formed with said first section, said second section being tearable from the first section, 
     said hinge section having a portion of reduced thickness juxtaposed to said rim, 
     said central section, channel and first section of the lid being rotatable about said portion of reduced thickness after tearing of said second section from said first section, thereby to effect opening of the lid. 
     In a preferred embodiment, said hinge section has means to lock the lid onto a pail. 
     In a still further aspect, the present invention provides a plastic lid for a pail having a peripheral rim, said lid having a substantially planar central section integrally formed with a peripheral channel section, said channel section adapted to fit over the rim of the pail to effect closure of the pail, 
     said channel section comprising an edge section that extends exterior to the pail around the periphery of said lid, said edge section having a first section, a second section and a third section, each of said first, second and third section extending peripherally around the edge section of the lid, said second section being intermediate said first and third sections and integrally formed with said first and third sections, said second section being tearable from the first and third sections, thereby to effect opening of the lid. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is illustrated by the embodiments shown in the drawings, in which: 
     FIG. 1 is a schematic representation of a side view of a pail, partly in section; 
     FIG. 2 is a schematic representation of a cross-section of a pail, with a lid being shown in a closed and open position; 
     FIG. 3 is a schematic representation of a plan view of a pail, without a lid; 
     FIG. 4 is a schematic representation of a plan view of a lid; 
     FIG. 4A is a schematic representation of a side view of the lid of FIG. 4, from position A; 
     FIG. 4B is a schematic representation of a side view of the lid of FIG. 4, from position B; 
     FIG. 4C is a schematic representation of a side view of the lid of FIG. 4, from position C; 
     FIG. 4D is a schematic representation of a side view of the lid of FIG. 4, from position D; 
     FIG. 5 is a schematic representation of the pull tab of section E of the lid of FIG. 4; 
     FIG. 6 is a schematic representation of a cross-section of the lid of FIG. 4, through F—F; 
     FIG. 7 is a schematic representation of the rim of section G of the lid of FIG. 6; 
     FIG. 8 is a schematic representation of the rim of section H of the lid of FIG. 6; 
     FIG. 9 is a schematic representation, in part, of the rim of section I of the lid of FIG. 2; and 
     FIG. 10 is a schematic representation of a side view of a section of a pail, showing the base of a handle. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a plastic pail partially in section and generally indicated by  10 . Pail  10  is preferably an injection moulded plastic pail, and may be formed from a variety of polymers, especially high-density polyethylene or polypropylene. Pail  10  is suitable for holding and transporting a wide variety of products or materials. Pail  10  may be made in a variety of sizes, for example sizes in the range of from about 1 L to about 25 L. In embodiments, pail  10  is a 15 L or 16 L pail. As discussed herein, pail  10  may be of any convenient cross-sectional shape, but circular, square and rectangular shapes are preferred. The invention is particularly described herein with reference to a pail with a square cross-section, which is a preferred shape. 
     Pail  10  has side wall  12  that extends between rim  18 , at open end  20 , and bottom edge  13  at bottom  14 . Bottom  14  is shown as being slightly recessed from bottom edge  13 , especially at gate  16 , which is centrally located on bottom  14 . It will be noted that side wall  12  is tapered, as is known, so that a pail  10  may be stacked with another pail  10  during transportation of empty pails. 
     Side wall  12  has two circumferential reinforcing ribs,  22  and  24 , that are in a juxtaposed but spaced apart position on side wall  12 . Ribs  22  and  24  are spaced from rim  18 . Ribs  22  and  24  are moulded integrally with side wall  12 . Rib  22  has latch projection  19  thereon, in a central location along the side of pail  10 . Latch projection  19  projects from rib  22 , and is intended to engage with a corresponding latch slot in the lid of the pail, as described below. Side wall  12  also has circumferential skirt  26  that is spaced from rib  24  and distal to rim  18 . Skirt  26  is moulded integrally with side wall  12 . 
     As discussed below, latch projection  19  in a latch slot retains the lid on the pail during transportation and storage i.e. until such time as pail  10  is to be opened. After opening, latch projection  19  in a latch slot retains the lid on the pail and provides support for the hinge. 
     FIG. 2 shows a cross-section of pail  10  in combination with lid  28 . In addition, FIG. 2 shows a part of a second pail  10 A nesting on top of lid  28 , as well as showing lid  28  in an open position, as indicated by  28 A. Lid  28  is preferably an injection moulded plastic lid, which may be formed from the same polymer or a different polymer from that of pail  10 . A preferred polymer is polyethylene. 
     Lid  28  covers open end  20  of pail  10 . Lid  28  has a central generally planar section,  30 , which extends substantially across the width of lid  28 . Central planar section  30  terminates in groove  32 , which in turn is connected to lid rim  36 . Lid rim  36  extends upwards from groove  32 , and is an inverted U-shape to fit over rim  18  of pail  10 . Lid rim  36  has an internal rib  37  within the inverted U-shape, which extends downward and is intended to be in contact with the interior surface of side wall  12 , as further illustrated in FIG.  9 . Internal rib  37  forms part of the seal of lid  28  with pail  10 , to retain the contents of pail  10  within the pail during transportation and storage. 
     Central planar section  30  is recessed with respect to lid rim  36 . In addition, lid  28  is shown with centre portion  39  that is slightly recessed with respect to the remainder of central planar section  30 . Recessed centre portion  39  is optional and may be replaced with other shapes or omitted. It is intended that recessed centre portion  39  will facilitate stacking of another pail on lid  28 , as discussed below. Centre portion  39  would normally be the location of the gate used in injection moulding of lid  28 . 
     The periphery of lid  28  extends downwards from lid rim  36 , and down the exterior of pail  10 . The periphery of lid  28  forms lid edge  38 , which is described in more detail below. It will be noted that lid edge  38  contacts both of reinforcing ribs  22  and  24 , which will also be discussed below. 
     It will be noted that bottom edge  13 A of pail  10 A fits into groove  32  of lid  28 . Bottom edge  13 A is conveniently adjacent to the upwardly extending wall  34  of lid rim  36 , to provide stability in the stacking of pails. 
     FIG. 2 also shows lid  28  on pail  10  in an open position, as indicated by  28 A. Lid  28 A is retained on rim  18  by hinge  50 , which is discussed in greater detail below. 
     FIG. 3 shows a plan view of pail  10 , without a lid. Thus, pail  10  has open end  20 . Side wall  12 , which is tapered, extends downwards to bottom  14 , with gate  16  being shown. Rib  22  extends around rim  18  and is located below rim  18 , as shown in FIGS. 1 and 2. Handle bases  17 A and  17 B extends outwards from pail  10 ; handle bases are further illustrated in FIG.  10 . It is understood, however, that a variety of handle bases and associated handles may be used on the pail, including handles that are integrally moulded with pail  10 . Pail  10  also has grips  21  that extend outwards from side wall  14 . 
     FIG. 4 shows a plan view of lid  28 . In the embodiment shown, lid  28  is a square lid, although the lid may be of other shapes. The hinge, which is not shown in FIG. 4, is integral with lid  28 . Consequently, with the square lid of FIG. 4, the lid may be placed on a pail  10  in a number of orientations i.e. the lid may be rotated through 90°, 180° or 270° from the position shown and still placed directly onto pail  10 . With a rectangular lid and pail, the lid could be rotated through 180°, and with a circular lid and pail, the lid could be placed on the pail at any orientation, subject to provision of latch projections. It will be appreciated that the ability to place the lid on the pail at any of the orientations that are obvious for a particular shape of lid is of substantial convenience to persons involved in the filling of pails, and is an important feature of embodiments of the present invention. 
     FIG. 4 shows lid  28  as having a central planar section  30 . In the embodiment shown, lid  28  has centre section  39 , which is optional but is typically the located of the injection moulding gate. Groove  32  extends around the periphery of central planar section  30 . Groove  32  is smoothly contoured into wall  34  of lid rim  36 . 
     FIGS. 4A-4D show edge views of lid  28 , from positions A-D shown in FIG.  4 . FIG. 4A shows the position of the hinge in lid  28 . 
     FIG. 4A shows the edge of lid  28  that has the hinge section, generally indicated by  50 . As shown in FIGS. 4B-4D, lid edge  38  is formed of three sections viz. first section  41 , second section  42  and third section  43 , with second section  42  being a breakaway section. However, at hinge section  50  shown in FIG. 4A, third section  43  extends to lid rim  36  i.e. there is no breakaway section at hinge  50 . Third section  43  forms a continuous section with hinge base  47 . 
     Latch slot  35  is centrally located in third section  43 . Latch slot  35  is cooperatively located with respect to latch projection  19  on rib  22  of pail  10 , to engage latch projection  19  when lid  28  is placed on pail  10  after the filling of pail  10 . Moreover, it is intended that latch projection  19  be retained in latch slot  35  and only removable therefrom with excessive force. This is not necessary during normal use, because lid  28  is rendered removable from pail  10  by tearing away second section (breakaway section)  42 , as discussed herein. 
     On the opposed sides of hinge base  47  are pull tabs  46 A and  46 B, with their respective finger slots  48 A and  48 B. Tear lines  44  and  45  extend from pull tab  46 A and extend around the circumference of lid  28  to pull tab  46 B. Each of pull tabs  46 A and  46 B is integrally connected to breakaway (second) section  42 . 
     FIG. 4B shows a side view of lid  28 . Lid edge  38  extends downwards from lid rim  36 , and is formed of three sections viz. first section  41 , second section  42  and third section  43 . First section  41 , which is the upper section, is smoothly contoured with lid rim  36 . First section  41  is integrally connected to second section  42  along tear line  44 . Similarly, second section  42  is integrally connected to third section  43  along tear line  45 . The breakaway section (second section  42 ) is shown as tapering in width at taper  40 . As discussed below, second section  42  is a breakaway section that may be separated from first section  41  and third section  43  by tearing along tear lines  44  and  45 . This occurs during the opening of pail  10  for discharge of its contents. 
     First section  41  is of a narrower width along the side that has the hinge section (see FIG.  4 A), to permit opening of lid  28 . However, first section  41  is preferably of greater width along the remaining three sides of lid  28  so that a more effective re-closure of lid  28  may be obtained after pail  10  has been opened (see FIGS.  4 B- 4 D). 
     FIG. 4B also shows latch slot  35  centrally located along lid edge  38 , in third section  43  of lid edge  38 . 
     FIG. 4D shows a view that is identical to the view of FIG. 4B, but in reverse image. However, FIG. 4C shows a view that differs from that of FIGS. 4B and 4D in that tear lines  44  and  45  are linear across the entire width of lid  28 . 
     In operation, lid  28  is placed on pail  10  after the pail has been filled. Lid  28  is snapped closed, such that each latch projection  19  is inserted into and retained in a corresponding latch slot  35 . The pail may then be shipped for sale. After sale, the pail is opened by pulling on each of pull tabs  46 A and  46 B, and tearing the breakaway section (section  42 ) away from the first and third sections (sections  41  and  43 ). The entire breakaway section is removed. The remaining part of lid  28  may be lifted into an open position using hinge  50 . Third section  43  remains on pail  10 , and forms a strap to hold hinge  50  on the pail, being anchored in position using latch projections  19  and latch slots 35 . Further details of the structure and operation of the hinge and breakaway section are given below. 
     FIG. 5 shows an enlarged view of the area identified as E in FIG.  4 A. Pull tab  46 A is attached to second or breakaway section  42 , and is adapted to tear from the lid along tab tear line  49 , and then along tear lines  44  and  45 . Finger slot  48 A is provided so that a finger (or an instrument) may be inserted under pull tab  46 A for the purpose of removal. In addition, pull tab  46 A has a plurality of ridges  66 , to facilitate gripping of pull tab  46 A for removal thereof. Finger slot  48 A has a contoured edge, at  51 , for ease of entry into the slot. Pull tab  46 A is separated from hinge base  47  at channel  52 , for ease of opening of the lid. Channel  52  terminates at first section  41 , and thus first section  41  extends into hinge  50 . 
     FIG. 6 shows a cross-section of lid  28 , along line F—F of FIG.  4 . Lid  28  has central planar section  30  with center portion  39 . Central planar portion  30  terminates at groove  32 . Wall  34  of lid rim  36  extends from groove  32  on the side opposed to central planar portion  30 . Detail of the edge of lid rim  36  in the area identified as “G” is discussed below. 
     Lid rim  36  is smoothly contoured into lid edge  38 . The construction of lid edge  38  is discussed below, with reference to “H”. 
     FIG. 7 shows groove  32  contouring into wall  34 , which in turn contours into lid rim  36 . Lid rim  36  extends into lid edge  38 , and forms hinge  50  in doing so. Hinge  50  is characterized by a section of reduced thickness at junction  54  between lid rim  36  and lid edge  38 . The thickness of lid edge  38  at junction  54  must be such that the portion of lid with groove  32  and central planar section  30  (not shown) may be rotated about junction  54  of hinge  50 , to open pail  10 . When lid  28  moves upwards, lid edge  38  remains in position as it is in contact with ribs  22  and  24  as shown below. In addition to the ability to hinge at junction  54 , junction  54  must be of sufficient thickness to provide strength so that lid  28  remains connected to and part of lid edge  38 . 
     In FIG. 7, junction  54  is shown to be a planar section at an angle of 45° to the plane of lid rim  36 . It is to be understood, however, that such angle may be varied e.g. through a range of 35-60° and moreover that it may be a non-planar section. 
     FIG. 8 shows the section identified as “H” in FIG.  6 . Lid  28  has groove  32  that extends into wall  34  and to lid rim  36 . Internal rib  37  extends downwards from lid rim  36  and is connected to spacer  56 , which is intended to facilitate separation of lids when stacked. Lid rim  36  is contoured smoothly through edge  58  into lid edge  38 . Lid edge  38  has first section  41 , second (or breakaway) section  42  and third section  43 . First section  41  is separated from second section  42  by notch  60 , and second section  42  is separated from third section  43  by notch  62 . Notches  60  and  62  correspond with tear lines  44  and  45  described above. 
     FIG. 9 shows a lid  28  on a pail  10 , in cross section. The cross section is the area indicated as “I” in FIG.  2 . Lid  28  fits over rim  18  of pail  10 , with internal rib  37  against the part of side wall  12  adjacent to rim  18 . Side wall  12  has ribs  22  and  24  extending therefrom. Rib  22  is shown with latch projection  19  thereon. Lid edge  38  is shown with hinge base  47  that extends downwards on the outside of side wall  12  of pail  10  past rib  22  to a position that is juxtaposed to rib  24 . Latch projection  19  on rib  22  extends through latch slot  35 . Latch projection  19  in latch slot  35  serves to anchor hinge base  47  on pail  10 , so that it remains in position during and after opening of lid  28 . 
     FIG. 10 shows a section of a pail  10 , with rim  18 , ribs  22  and  24  and skirt  26 . Skirt  26  is shown as having handle connector  64  therein. Handle connector  64  has handle base  17  and handle slot  65 . It is understood that a handle with cooperating sections would be fitted into handle connector  64 . Such a handle is described in greater detail in U.S. Pat. No. 5,816,439. As discussed herein, any suitable handle may be attached to pail  10 , and that any such handle would normally be attached into skirt  26 . An appropriate connector, or entire handle, would be located as required. 
     In use, pail  10  is filled with the material to be packaged. Lid  28  is then applied to pail  10 . As discussed above, the lid of the present invention and may be applied to a square container in any of the four possible orientations. For a rectangular container, there are two possible orientations, and for a circular container there could be a multitude of orientations. The lid is snapped closed, so that latch projections  19  enter latch slots  35  and preferably lock therein. This latches the lid to the pail, and preferably does so in a manner that prevents the lid from being removed without showing evidence of such removal. Thus, in preferred embodiments, the lid of the invention also acts as a tamper-proof and a tamper-evident lid. In such embodiments, the lid acts to provide both a hinge and evidence of tampering. For removal of the lid e.g. after transportation and sale of the filled pail, a finger or a device is inserted into one or both of finger slots  48  and the pull tab is pulled. This effects tearing of the breakaway section from the lid for the full circumference of the container except that portion where the hinge is located. Some or all of the contents of the pail may then be removed. The pail may be closed merely by closing the lid. 
     The lid is always conveniently located, as it remains attached to the pail. Moreover, the lid remains substantially free of contamination. For instance, the lid is not removed from the pail and placed on the floor or other object where it might be walked on, dislodged, contact dust, dirt or other contamination or misplaced. The lid is also of a construction such that it will remain closed, or at least substantially closed, after opening and re-closure. 
     After opening, third section  43  remains attached to the pail, and extends for the full circumference of the pail. This anchors the hinge in place, and provides stability during opening and closing of the lid. It also prevents the lid from being removed from the pail. 
     The invention has been described herein with reference to the lid having first section  41 , second section  42  and third section  43 . In an alternate embodiment of the invention, third section  43  is omitted from the lid. Thus, the lid would have first section  41  and second section  42 , the latter being a breakaway section as described herein. After removal of second section  42 , the lid would have first section  41  but the third section described previously and which retains the lid on the pail would be absent. Alternate means of attachment of first section  41  to the pail may be required e.g. ratchet systems, hooks, interlocking curved sections or other locking systems. Such locking systems would preferably be integrally moulded into the lid and/or pail. Thus, in use second section  42  would show evidence of opening of the pail i.e. evidence of tampering, and the lid would normally be retained on the pail after opening. 
     In a further embodiment, second section  42  could be a breakaway section around the entire circumference of the lid. In this embodiment, second section  42  would be a breakaway section through the hinge section described above. Consequently, the lid would be detachable from the pail, being no longer a hinged lid. Third section  43  would remain on the pail, and would be evidence of tampering with the pail. In this embodiment, the hinge section described above could be omitted. The lid after removal of second section  42  would be a replaceable lid. The lid and pail would be a tamper evident combination, but without a hinged lid. 
     The hinged lid of the present invention, the pail and the pail with lid are capable of being stacked and shipped, both filled and prior to filling. Thus, the lid and pails are convenient for storage, easily assembled after filling of the pail, are stackable for shipping either separately or filled and show evidence of any tampering or opening. The alternate embodiments further provide lids and pails that show evidence of tampering.