Patent Publication Number: US-7909236-B2

Title: End caps for tubes and shipping containers formed therefrom

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation-in-part of U.S. Ser. No. 11/079,739, filed Mar. 14, 2005, which is a continuation-in-part of U.S. Ser. No. 10/801,786, filed Mar. 16, 2004. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to an end caps that can be releasably secured to tubes, and shipping containers formed therefrom. 
     2. Description of Related Art 
     In co-pending U.S. Ser. Nos. 10/801,786 and 11/079,739, both of which are hereby incorporated by reference in their entirety, the applicant herein disclosed several embodiments of end caps that were adapted to releasably secure to tubes to form shipping containers. In one such embodiment, the end cap included a sidewall that was adapted to be received within an open end of the tube such that an inner side of the tube was surrounded the sidewall of the end cap. The sidewall of the end cap included at least one projection biased on a deflectable tab portion of the sidewall to extend away from the sidewall into a mounting opening formed in the tube proximal to the open end. This arrangement advantageously inhibits the end cap from inadvertently becoming dislodged from the tube. It also allows the end cap to be removed simply by rotating the end cap relative to the tube until the projection is no longer extending into the mounting opening and then withdrawing the end cap from the tube. 
     Although the various embodiments of end caps and shipping containers disclosed in co-pending U.S. Ser. Nos. 10/801,786 and 11/079,739 provide many advantages over the prior art, there is still additional room for improvement. For example, in the embodiment previously described above, the outer diameter of the sidewall must be smaller than (or about the same as) the inner diameter of the tube because the sidewall of the end cap must be received within the open end of the tube such that the inner side of the tube is surrounded the sidewall of the end cap. This means that there may be gaps between the outer side of the sidewall and the inner side of the tube that can allow air and moisture to infiltrate the shipping container. 
     SUMMARY OF THE INVENTION 
     The present invention provides end caps that are adapted to releasably secure to a first open end of a tube, and shipping containers therefrom. The end caps according to the invention include a deformable sealing element becomes deformed against an inner side of the tube when the end cap is disposed within the tube. The sealing element forms a circumferential seal between the end cap and the tube such that the end cap completely plugs a passageway through the tube. The circumferential seal between the end cap and the tube substantially inhibits air and water infiltration into and out of the shipping container. 
     More particularly, an end cap according to the present invention comprises a base, a sidewall surrounding and extending from the base, at least one movable projection biased to extend beyond the outer side of the sidewall, and a deformable sealing element extending from a perimeter of the base and/or from the outer side of the sidewall. When the end cap is secured to the tube, an inner side of tube surrounds the outer side of the sidewall of the end cap, the movable projection extends into a mounting opening formed in the tube proximal to the first open end, and the sealing element is deformed against the inner side of the tube to form a circumferential seal between the end cap and the tube such that the end cap completely plugs a passageway through the tube. 
     The foregoing and other features of the invention are hereinafter more fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the present invention may be employed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a portion of a tube showing mounting openings formed proximal to an open end. 
         FIG. 2  is a previously disclosed embodiment of an end cap for releasable engagement with the paper tube shown in  FIG. 1 . 
         FIG. 3  is a detailed perspective view of a portion of the end cap shown in  FIG. 2 . 
         FIG. 4  is a perspective view of the end cap shown in  FIG. 2  secured to the tube shown in  FIG. 1  to form a shipping container. 
         FIG. 5  is a detailed perspective view of a portion of the shipping container shown in  FIG. 4 . 
         FIG. 6  is a perspective view of one embodiment of an end cap according to the present invention. 
         FIG. 7  is a detailed perspective view of a portion of the end cap shown in  FIG. 6 . 
         FIG. 8  is a detailed perspective view of a portion of another embodiment of an end cap according to the present invention. 
         FIG. 9  is a detailed perspective view of a portion of yet another embodiment of an end cap according to the present invention. 
         FIG. 10  is a detailed perspective view of a portion of yet another embodiment of an end cap according to the present invention. 
         FIG. 11  is a detailed perspective view of a portion of the end cap shown in  FIG. 10  with the O-ring removed. 
         FIG. 12  is a detailed perspective view of a portion of yet another embodiment of an end cap according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A perspective view of a portion of a tube  10  is shown in  FIG. 1 . The tube  10  comprises a cylindrical body  20  having at least one open end  30 . At least one or, more preferably, a plurality of mounting opening  40  are formed in the cylindrical body  20  adjacent to the open end  30 . The mounting openings can have any shape. Preferably, a plurality of mounting openings  40  are spaced an equal distance apart radially about the cylindrical body  20  adjacent to the open end  30 . The tube  10  can be of any size and can be provided with as many or as few mounting openings  40  as desired. Tubes  10  having an inner diameter of about four inches or less are preferably provided with at least two, and more preferably, three or more mounting openings  40 . 
     The tube  10  can be formed of plastic or paper using conventional tube manufacturing techniques. The mounting holes  40  can be formed by cutting, punching or by other forming means. When the tube is made of paper, the wall thickness of the cylindrical body  20  is preferably within the range of from about 0.050 inches to about 0.250 inches, with wall thicknesses of 0.070 inches to about 0.125 inches being most preferred. The cylindrical body  20  can be of any desired length. 
     A perspective view of one embodiment of an end cap  50  such as previously disclosed in applicant&#39;s co-pending applications is shown in  FIG. 2 . In this embodiment, the end cap  50  comprises a sidewall  60  and at least one or, more preferably, a plurality of projections  70  that extend or project outwardly away from the sidewall  60 . 
     With reference to  FIG. 3 , which shows a detailed perspective view of a portion of the end cap  50  shown in  FIG. 2 , each projection  70  is preferably formed on a deflectable tab portion  80  of the sidewall  60 . The shape and orientation of the deflectable tab portion  80  is not critical, and a variety of shapes or configurations can be used. However, the deflectable tab portion  80  should be sized and configured to facilitate sufficient inward deflection of the tab portion  80  that a top edge portion  90  of the projection  70  does not extend beyond the sidewall  60  of the end cap  50 . This is necessary in order to facilitate removal of the end cap  50  from the tube  10 . 
     As is shown in  FIG. 3 , the projection  70  also preferably comprises a bottom ramp portion  100  arranged on a side opposite the top edge portion  90 . The bottom ramp portion  100  preferably provides a gradual or angled approach from the sidewall  60  to a tip  110  or farthest point of the projection  70 . The bottom ramp portion  100  promotes inward deflection of the deflectable tab portion  80  when the end cap  50  is pressed into the open end  30  of the tube  10 . 
     The projection  70  also preferably comprises a side ramp portion  120  that is arranged on or both sides of the projection  70  between the top edge portion  90  and the bottom ramp portion  100 . Like the bottom ramp portion  100 , the side ramp portion  120  provides a gradual or angled approach from the sidewall  60  to a tip  110  or farthest point of the projection  70 . 
     It will be appreciated that the shape of the projection  70  is not per se critical, and that rounded “bumps” with a generally flat top edge portion  90  or other shapes could be used. It will also be appreciated that the deflectable tab portion  80  and the projection  70  can be coextensive. It is important, however, that the top edge portion  90  of the projection  70  be able to contact the top peripheral edge  180  (see  FIG. 5 ) of the mounting opening  40  to prevent the removal of the end cap  50  from the tube  10 , and that the projection  70  be able to be positioned (by rotation) such that it no longer projects into the mounting opening  40 . 
     The end cap  50  also preferably comprises a peripheral rim portion  130  that extends beyond the sidewall  60 . The peripheral rim portion  130  extending beyond the sidewall  60  will contact a perimeter edge of the open end  30  of the tube  10  thus limiting the extent to which the end cap  50  can be received within the open end  30  of the tube  10 . This advantageously prevents the end cap  50  from being pushed too far into the tube  10 , past the point where the projection(s)  70  would be aligned with the mounting opening(s)  40 . 
     The end cap  50  also comprises a base  140  that is surrounded by and extends between the sidewall  60 . The base  140  can extend between the sidewall  60  at any point (i.e., at the bottom or at the top or at any point in between), but is preferably nearer to a lower or bottom portion  150  of the sidewall  60  below the deflectable tab portion  80 . In  FIG. 2 , the base  140  extends from the lower or bottom portion  150  of the sidewall  60 . 
     Preferably, the base  140  further comprises a handle portion  160  for facilitating rotation of the end cap  50  relative to the tube  10 . The shape and configuration of the handle portion  160  is not critical, but should provide a comfortable gripping surface for one&#39;s fingers. 
     The end cap is preferably formed of a plastic material such as polystyrene, polyethylene, polypropylene, nylon and/or one or more other thermoplastic or thermosetting polymers. The end cap can be formed using conventional molding or fabricating processes and equipment. 
       FIG. 4  shows a perspective view of a shipping container  170  that can be formed by joining a tube  10  such as shown in  FIG. 1  and an end cap  50  such as shown in  FIG. 2  together. As shown in FIG.  4 ., the end cap  50  closes off the open end  30  of the tube  10 . The end cap  50  is received within the open end  30  of the tube  10  such that the cylindrical body  20  radially surrounds the sidewall  60  of the end cap  50 . At least one projection  70  extends away from the sidewall  60  and into a mounting opening  40  so as to releasably secure the end cap  50  to the tube  10 . 
     With reference to  FIG. 5 , which shows a detailed perspective view of a portion of the shipping container  170  shown in  FIG. 4 , the top edge portion  90  of the projection  70  is arranged to contact against a top peripheral portion  180  of the mounting opening  40  to thereby prevent withdrawal of the end cap  50  from the tube  10 . Rotation of the end cap  50  relative to the tube  10 , however, causes the side ramp portion  120  to contact a side peripheral portion  190  of the mounting opening  40 , which causes inward deflection of the deflectable tab portion  80  sufficient to prevent engagement or contact between the top edge portion  90  and the top peripheral portion  180  of the mounting opening  40 . Once the projection  70  is no longer aligned with and extending into the mounting opening  40 , the end cap  50  can simply be withdrawn or pulled from the open end  30  of the tube  10 . 
     With reference to  FIGS. 6-12 , end caps  50  according to the present invention comprise a base  140 , a sidewall  60  surrounding and extending from the base  140 , at least one movable projection  70  biased to extend beyond the outer side of the sidewall  60 , and a deformable sealing element  200  that extends from a perimeter of the base  140  and/or from the outer side of the sidewall  60 . When the end cap  50  according to the present invention is secured to the tube  10 , an inner side of tube  10  surrounds the outer side of the sidewall  60  of the end cap  50 , the movable projection  70  extends into a mounting opening  40  formed in the tube  10  proximal to the first open end  30 , and the sealing element  200  is deformed against an inner side of the tube  10  to form a circumferential seal between the end cap  50  and the tube  10  such that the end cap  50  completely plugs a passageway through the tube  10 . 
     In the embodiment of the end cap according to the invention shown in  FIGS. 6 and 7 , the sealing element  200  comprises a fin  210  that extends from the perimeter of the base  140  at or very near where the outer side of the sidewall  60  meets the base  140 . It will be appreciated that the sealing element  200  can extend from the base  140  and/or from the outer side of the sidewall  60 . The fin  210  can extend generally perpendicular from the sidewall  60  or generally parallel to the base  140 , or it can extend away from the base  140  and/or sidewall  60  at an angle. The fin  210  shown in  FIGS. 6 and 7  is angled toward the rim portion  130  of the end cap  50 .  FIG. 8  shows an alternative embodiment in which the fin  210  is angled away from the rim portion  130  of the end cap  50 . 
     The sealing element must extend beyond the outer side of the sidewall  60  of the end cap  50  a distance sufficient that it can make contact with the inner side or surface of the tube  10  when the end cap  50  is pressed into the tube  10 , base  140  first. The outer peripheral portion of the sealing element  200  is preferably circular in shape, but may have a shape other than that of a circle provided it can deform to form a seal against the inner side of the tube  10 . 
       FIG. 9  shows another embodiment of an end cap  50  according to the invention in which the sealing element  200  comprises two spaced apart fins  210   a  and  210   b , one ( 210   a ) extending from the outer side of the sidewall  60  and one ( 210   b ) extending from the perimeter of the base  140 . It will be appreciated that the sealing element  200  can include a plurality of fins  210 , which may extend from the outer side of the sidewall  60  and/or the base  140  at any angle. 
     In the embodiments of end caps  50  according to the invention shown in  FIGS. 6-9 , the fin  210  or fins  210   a ,  210   b  are formed integrally with the base  140  and/or sidewall  60  of the end cap  50  from which the fin  210  or fins  210   a ,  210   b  extend. The end caps  50  are preferably formed of a plastic material, and thus in these embodiments, the fin  210  or fins  210   a ,  210   b  are also preferably formed of plastic. In order to allow the fin  210  or fins  210   a ,  210   b  to deform and form a good seal between the end cap  50  and the inner side of the tube  10 , it may be necessary for the fin  210  or fins  210   a ,  210   b  to have a tapered cross section, with the thickest dimension being proximal to the outer side of the sidewall and/or base, and the thinnest dimension being distal to thereto. 
       FIGS. 10 and 11  show an end cap  50  according to yet another embodiment of the present invention. In the embodiment illustrated in  FIGS. 10 and 11 , the deformable sealing element  200  comprises an elastomeric O-ring  220  that is received in a groove  230  or a channel formed on the outer side of the sidewall  60 . The elastomeric O-ring  220  is preferably formed of natural rubber or a synthetic elastomer material. When an end cap  50  such as shown in  FIGS. 10 and 11  is inserted into a tube  10 , base  140  first, the O-ring  220  is compressed against the inner side of the tube  10  an thus forms a circumferential seal between the end cap  50  and tube  10  that inhibits the infiltration of air and water into or out of the tube  10  around the end cap  50 . 
       FIG. 12  shows yet another embodiment of an end cap  50  according to the invention. In the embodiment shown in  FIG. 12 , the elastomeric O-ring  220  comprises a plurality of spaced apart circumferential beads  240   a ,  240   b . The beads  240   a ,  240   b  compress and/or otherwise deform against the inner side of the tube  10  when the end cap  50  is inserted, base  140  first, into the tube  10 . An O-ring  220  having a pair (or more than a pair) of spaced apart circumferential beads  240   a ,  240   b  is believed to form a better seal between the end cap  50  and the tube  10  than an O-ring  220  having no bead  240  or only one bead  240 . 
     End caps according to the present invention may include the same features and elements (e.g., lock members, polygonal peripheral rim portions etc.) as the end caps disclosed in applicant&#39;s co-pending U.S. Ser. Nos. 10/801,786 and 11/079,739, which have been incorporated by reference in their entirety. In the presently most preferred embodiment of the invention, an end cap according to the invention comprises a plurality of movable projections biased to extend beyond the outer side of the sidewall such that when the end cap is secured to a tube, each one of the plurality of movable projections extends into one of a plurality of mounting openings spaced radially about the tube proximal to the first open end. Preferably, each of the plurality of projections extends from a deflectable tab portion of the sidewall. Furthermore, for the reasons explained in the co-pending applications, each of the plurality of projections preferably comprises a side ramp portion for contacting an edge of the mounting opening into which the projection extends when the end cap is rotated relative to the tube to promote inward deflection of the tab portion until the projection no longer extends into the mounting opening thus allowing the end cap to be removed from the tube. 
     The end caps according to the present invention are particularly useful for closing an open end of a tube that is to be used a shipping container. An end cap according to the invention can be securely attached to a tube quickly and without the need for special tooling, and can be removed by hand with relative ease. The end caps of shipping tubes formed in accordance with the invention are significantly more difficult to unintentionally dislodge from an open end of a tube as compared to conventional plastic plugs or other tube end closures. 
     A shipping container according to the invention thus comprises a tube and at least one end cap according to the invention. It will be appreciated that an end cap according to the invention can be applied to both ends of the tube or simply one end. The tube of the shipping container according to the invention comprises a cylindrical body having an inner side and an inner diameter D 1 , a first open end, and at least one mounting opening formed in the cylindrical body proximal to the first open end. The end cap of the shipping container according to the invention, as noted above, is removably securable to the tube and comprises a base, a sidewall surrounding and extending from the base, the sidewall having an outer side having an outer diameter D 2  that is less than or equal to the inner diameter D 1  of the cylindrical body of the tube, at least one movable projection biased to extend beyond the outer side of the sidewall, and a deformable sealing element extending from a perimeter of the base and/or from the outer side of the sidewall. When the end cap is secured to the tube, the inner side of the cylindrical body surrounds the outer side of the sidewall of the end cap, the movable projection extends into the mounting opening formed in the cylindrical body of the tube proximal to the first open end, and the sealing element is deformed against the inner side of the tube to form a circumferential seal between the end cap and the tube such that the end cap completely plugs a passageway through the tube. 
     In one preferred embodiment, a shipping container according to the invention comprises an end cap made of plastic and a tube made of paper. In another preferred embodiment, a shipping container according to the invention comprises an end cap made of plastic and a tube that is also made of plastic. The plastic used to manufacture the end cap and/or the tube can be opaque, translucent or transparent. Semi-transparent plastic tubes with opaque plastic end caps make excellent shipping containers. The semi-transparent plastic tubes allow one to rapidly visually determine whether an object is stored within the tube or not. Furthermore, the end caps can be color coded to help identify the contents of the container. 
     The peripheral edge portion of the rim portion of the end caps used in shipping containers according to the invention preferably define a polygonal shape, such as a triangle, which makes tube less likely to roll. This helps keep the tube on conveyor belting used in package distribution centers. 
     The sealing element is preferably disposed nearer the base than the deflectable tab portion of the sidewall of the end cap. Thus, when the end cap is pressed into a tube, the circumferential seal formed between the end cap and the inner side or wall of the tube together with the base (and a portion of the sidewall below the sealing element, if the sealing element extends from the sidewall) form a plug that inhibits the infiltration of water and air into and out of the container. This seal is particularly strong when the sealing element is formed of an elastomeric material and the tube is formed of plastic. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and illustrative examples shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.