referring to the accompanying drawings , where like numerals identify like elements , and initially to fig1 , and 10 , there is shown one form of a drinking vessel according to the present invention , in the form of a cup identified generally by reference numeral 20 . the cup 20 has a body 22 and a cap 24 with a spout 26 . a receptacle 28 for dry material is clipped onto the bottom of the cup . throughout this specification , terms such as “ top ”, “ bottom ,” and “ vertical ” are used in the interest of clarity with reference to an orientation of the cup 20 in a typical resting position , standing on a level surface with the spout 22 uppermost , as shown in fig1 . it is not required that the cup be maintained exactly in this orientation . in use , it will usually be necessary to tip the cup in order to drink from it . also , when empty , the cup , or its separate parts if it is dismantled , may be stored and transported in any convenient orientation . in one embodiment , the body 22 is asymmetrical in plan view . as best seen in fig2 , the body 22 has a rounded bottom 30 bounded by a groove 32 that serves for the receptacle 28 to clip onto , and has a main side wall that narrows gradually towards the top , ending in a neck or inwardly - projecting shoulder 36 above which the body 22 widens to an externally screw - threaded mouth 38 . the cap 24 has an internally screw - threaded skirt 40 that threads onto the mouth 38 of the cup body 22 . the spout 26 has one or more holes or other openings 42 in its tip through which a user can drink liquid from the cup 20 . below the spout , there is a tubular seat 44 . the interior of the tubular seat 44 is substantially cylindrical . a valve unit indicated generally by the reference numeral 50 consists of a valve holder 52 , shown in fig5 and 6 , a valve retainer 54 , shown in fig7 , and a valve member 56 , shown in fig8 and 9 . the valve holder 52 has a base plate 60 , which in the position shown in fig1 is generally horizontal , and a downwardly projecting grip 62 . projecting upwards from the base plate 60 is a tube 64 , the inside of which opens through the base plate 60 and the outside of which is inserted , when the cup is assembled , into the seat 44 . as best seen in fig4 , the outside surface of the tube 64 is a gently tapering truncated conical surface , narrowest at the open top end , and widest at the bottom end , where it joins the base plate 60 . the tube 64 and the seat 44 are dimensioned to produce a snug , stable fit between the outside of the tube and the inside of the seat . the upper end of the tube 64 has an internal seat 66 for the valve member 56 , and above the internal seat an internal groove 68 into which the retaining ring 54 is a snap fit . the retaining ring 54 has an undersurface 70 that cooperates with the seat 66 to hold the valve member 56 , an external rib 72 that is a snap fit into the groove 68 and , above the rib 72 , a shoulder 74 that seats onto the upper rim of the tube 64 . as may be seen from fig4 , the outside diameter of the retaining ring 54 is less than that of the tube 64 , so that the retaining ring 54 does not foul the seat 44 . in one embodiment , retaining ring 54 is sonic welded to tube 64 . sonic welding can be done so that the retaining ring 54 and valve member 56 are not removable from the valve unit 50 in normal use . the valve member 56 consists of a soft , flexible material such as silicone rubber , with one or more slits or holes 58 that open or close as the valve member 56 is distorted by external forces . the valve member 56 may be of any suitable design that will permit liquid to drain from the spout 26 back into the cup body 22 when the cup is standing upright , will not leak to any appreciable extent if the cup is overturned , and will permit liquid to be sucked from the cup without great effort . thus , the valve member 56 has an opening force of at least 6 ″ ( 15 cm ) water gauge , but preferably not much more , for flow towards the spout 26 , but leaks slightly for even minimal head of liquid in the opposite direction . a suitable design of valve member 56 is shown in u . s . pat . nos . 5 , 409 , 144 ( brown ) and 5 , 439 , 143 ( brown et al . ), both assigned to liquid molding systems , inc ., of midland , mich ., which are herein incorporated by reference in their entirety . as is best seen in fig4 , the valve holder 52 is dimensioned so that , with the tube 64 inserted into the seat 44 and the cap 24 screwed onto the body 22 , the edge 76 of the base plate 60 lies just above the internal shoulder 36 on the cup body 22 , at least at the part of the edge 76 that is nearest to the tube 64 . in this position , the shoulder 36 prevents the valve unit 50 from moving downwards far enough for the tube 64 to disengage from the seat 44 . the risk that the unit 50 will separate from the cap 24 , leaving the spout 26 unprotected against spillage , is thus greatly reduced . the shoulder 36 and the neck below it also make the cup 20 easier for a child to grip securely , because even if the child &# 39 ; s grip is loose , the shoulder can rest on the child &# 39 ; s hand or hands and prevent the cup from slipping out of the child &# 39 ; s grasp . referring now to fig2 , the receptacle 28 comprises a lid 80 and a base 82 . the lid 80 has a downward skirt 84 , with an internal screw thread , and an upward skirt 86 . the upward skirt 86 is shaped to fit closely round the curved bottom 30 of the cup body 22 , and has at its rim an internal bead 88 that snaps into the groove 32 . inwardly of the skirts 84 and 86 , the lid 80 has an opening 89 that can be closed by a shutter 90 that rotates about a pivot 92 that snaps into a hole at the center of the lid . the base 82 of the receptacle 28 , which serves as a base for the cup 20 to stand on , has an external screw threaded mouth 94 , which screws into the downward skirt 84 of the lid 80 , and has a bottom 96 that is slightly concave , to reduce the risk of the cup 20 wobbling when resting on the bottom 96 . if the receptacle 28 is removed , the cup 20 may rest on the bottom 30 of the cup body 22 , which is also slightly concave . referring to fig3 , alternatively , a separate standing base 100 may be clipped on in place of the receptacle 28 . the base 100 shown in fig3 has an upper part 102 similar in shape to the upper part of the upward skirt 86 of the lid 80 shown in fig2 , including a bead 88 that snaps into the groove 32 in the body 22 of the cup 20 . a lower part 104 of the base 100 follows loosely the shape of the bottom 30 of the cup body 22 . the lower part 104 has downward bulges 106 that act as feet when the cup 20 is standing on the base 100 . there may be four bulges 106 evenly spaced round the base 100 . the right half of fig3 shows a section through a bulge 106 . the left half of fig3 shows a section between bulges 106 . the standing base 100 may be of soft , rubbery material , with less tendency to slide on smooth surfaces than the bottom 30 , which may be fairly hard and stiff for the structural integrity of the cup body 22 . drainage holes 108 may be provided in the bottoms of the bulges 106 . as is also shown in fig3 , the externally screw - threaded mouth 38 of the cup body 22 may be tilted relative to the bottom 30 , 96 , or 100 on which the cup 20 stands . in the arrangement shown in fig3 , the screw threads on the mouth 38 and the skirt 40 of the cap 24 are single - start threads , aligned so that with the lid 24 screwed tightly onto the body 22 the spout 26 is at the highest point of the mouth 38 . this may improve the drinking function of the cup 20 , because with the spout 26 at a convenient angle for drinking from the cup body 22 is then tipped higher . referring now to fig1 , an alternative form of the receptacle 128 comprises a lid 80 and a base 130 . the lid 80 of the receptacle 128 may be identical to the lid 80 of the receptacle 28 shown in fig2 and , in the interests of conciseness , description of the lid is not repeated . the base 130 of the receptacle 128 has an externally screw threaded mouth 94 , which screws into the downward skirt 84 of the lid 80 , and has a bottom 132 that is similar in shape to the bottom 30 of the cup body 22 , bounded by a groove 134 similar to the groove 32 . thus , the lid 80 of the receptacle 128 may clip either onto the bottom 30 of the body 22 of the cup 20 , or onto the bottom 132 of another similar receptacle 128 . the cup 20 may have a neck 36 and mouth 38 ( not shown in fig1 ) as shown in fig2 or fig3 . onto the bottom 132 of the receptacle 128 may be clipped either the standing base 100 shown in fig3 or the lid 80 of another similar receptacle 128 . as shown in fig1 , a stack may be formed by clipping together a cup 20 , one or more containers 128 , and a standing base 100 . alternatively , a stack of containers 128 without a cup 20 and / or without a standing base 100 may be formed , or a single receptacle 128 may be stacked with a cup 20 and / or with a standing base 100 . however , because the bottom 132 of the receptacle 128 is more rounded than the bottom 30 of the receptacle 28 , it may be preferred to use a standing base 100 to increase the stability of tall stacks . alternatively , the bottom of a stack may be a container lid 80 that does not have a container body screwed into it , or a container body 82 . the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and , accordingly , reference should be made to the appended claims , rather than to the foregoing specification , as indicating the scope of the invention . other variations are contemplated and will be understood by those in the art .
a drinking vessel comprising a container having a mouth and an internal shoulder ; a cap for closing the mouth of the container and having an outlet for liquid ; and a valve unit removably mountable on the cap and arranged to control flow of liquid to the outlet ; the valve unit being so arranged that the shoulder prevents the valve unit from being separated from the cap while the cap is mounted on the container . also , a drinking vessel comprising a container having an outlet for liquid ; and a receptacle removably attachable to an end of the container remote from the outlet of the container ; wherein the receptacle comprises parts relatively movable between a substantially closed position and a position providing an orifice for releasing objects from within the receptacle ; wherein the receptacle is arranged to be attached to the container in such a position that the container closes off the orifice .