P/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Invention Title: Cup Assembly The following statement is a full description of this invention, including the best method of performing it known to me: 2316353vl Cup Assembly BACKGROUND OF INVENTION 1. FIELD OF INVENTION The present invention relates to a paper cup and, more particularly, to a 5 cup assembly including a paper cup located in a paper sleeve, with an insulating space defined between the paper cup and the paper sleeve. 2. RELATED PRIOR ART Many drinks such as coffee, juice and tea are contained in disposable containers and sold. In consideration of convenience and cost, many drinks 10 are contained in paper cups. Paper cups are however poor in insulating and actually not good for containing hot drinks. That is, heat is easily transferred to a user's hand from a hot drink via a paper cup. Thus, a user feels hot in his or her hand and might get burnt in the worst scenario. Moreover, heat is easily transferred to the environment from a hot drink via a paper cup. Thus, 15 the drink gets cold easily. On the other hand, heat is easily transferred to a cold drink from the environment through a paper cup. Thus, the cold drink gets hot easily. As discussed above, the drink, hot or cold, loses its favor soon after it is contained in the paper cup. Moreover, paper cups are weak generally and could be deformed easily. In that case, a hot or cold drink could 20 be spilt or leaked easily. A spilt hot drink could burn a user in the hand. To overcome the foregoing problems, there has been devised at least one cup assembly including a paper cup located in a paper sleeve, with an insulating space defined between the paper cup and the paper sleeve. The paper cup includes a tubular body attached to a bottom element by adhesion. 25 The paper sleeve includes an internally retroflex lower edge. Thus, transfer of heat is not easy because of the insulating space. Moreover, the paper cup is reinforced by the paper sleeve. The use of the conventional cup assembly is however not without any problem. An upper edge of the paper sleeve is in contact with an upper edge of the paper cup. In fact, an upper portion of the paper sleeve is located very close to an upper portion of the paper cup so that 5 the insulating space is thin near the upper portion of the paper sleeve. Hence, the insulating effect of the insulating space is poor near the upper portion of the paper sleeve. However, the user tends to hold the upper portion of the paper sleeve while drinking the hot drink from the cup assembly and feels hot or might get burnt in the worst scenario. Moreover, heat is transferred to the 10 environment from the hot drink or transferred to the cold drink from the environment at a considerable rate. A paper cup includes an upper edge that is rolled, pressed and then coated with a plastic layer. Thus, the upper edge of the paper cup is made with a multi-layered configuration for providing an adequate rigidity. The 15 processing of the upper edge of the paper cup is however complicated and therefore expensive. The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art. SUMMARY OF INVENTION 20 It is the primary objective of the present invention to provide an inexpensive, insulating cup assembly. To achieve the foregoing objective, the cup assembly includes two sleeves, a bottom element, a ring and bosses. The sleeves are made of paper while the ring and bosses are made of a plastic material. The first sleeve is made 25 with a lower edge and an upper edge. The bottom element is attached to the lower edge of the first sleeve. The ring is formed on the upper edge of the 2 first sleeve. The bosses are formed on the first sleeve against the ring. The second sleeve is made of paper with a lower edge and an upper edge. The lower edge of the second sleeve is located against the bosses as the second sleeve is provided around the first sleeve. Thus, an adequate insulating 5 space is defined between the first and second sleeves. In an aspect, the first sleeve is made of PE-coated paper. In another aspect, the mouthpiece and the bosses are provided on the upper edge of the first sleeve by injection molding. In another aspect, the mouthpiece and the bosses are made of a 10 conventional plastic material, a biodegradable plastic material or a bio-plastic material. In another aspect, the bottom element is made of paper. The lower edge of the first sleeve is an internally retroflex edge engaged with an edge of the bottom element. 15 In an alternative aspect, the bottom element is made of a plastic material. The bottom element is made of a conventional plastic material, a biodegradable plastic material or a bio-plastic material. The bottom element includes two annular grooves for receiving the first and second sleeves so that the insulating space is adequate and constant from top to bottom. 20 In another aspect, the cup assembly further includes a ring made of plastic between the first and second sleeves near the lower edges so that the insulating space is adequate and constant from top to bottom. In another aspect, the lower edge of the second sleeve is an internally retroflex edge in contact with the first sleeve so that the insulating space is 25 adequate and constant from top to bottom. In another aspect, the cup assembly further includes an annular lip 3 extending from the mouthpiece so that an annular gap is defined between the annular lip and the bosses for receiving the upper edge of the second sleeve. In another aspect, the mouthpiece, the bosses and the annular lip are provided on the upper edge of the first sleeve via injection molding. 5 In another aspect, the mouthpiece, the bosses and the annular lip are made of a conventional plastic material, a biodegradable plastic material or a bio-plastic material. In another aspect, the cup assembly further includes a thermal foaming layer provided between the first and second sleeves. 10 Other objectives, advantages and features of the present invention will be apparent from the following description referring to the attached drawings. BRIEF DESCRIPTION OF DRAWINGS The present invention will be described via detailed illustration of six embodiments referring to the drawings wherein: 15 FIG. 1 is a perspective view of a cup assembly in accordance with the first embodiment of the present invention; FIG. 2 is an exploded view of the cup assembly shown in FIG. 1; FIG. 3 is a cross-sectional view of the cup assembly shown in FIG. 1; FIG. 4 is a cross-sectional view of a cup assembly in accordance with the 20 second embodiment of the present invention; FIG. 5 is a cross-sectional view of a cup assembly in accordance with the third embodiment of the present invention; FIG. 6 is a cross-sectional view of a cup assembly in accordance with the fourth embodiment of the present invention; 25 FIG. 7 is a cross-sectional view of a cup assembly in accordance with the fifth embodiment of the present invention; and 4 FIG. 8 is a cross-sectional view of a cup assembly in accordance with the sixth embodiment of the present invention. DETAILED DESCRIPTION OF EMBODIMENTS Referring to FIGS. 1 through 3, there is shown a cup assembly in 5 accordance with a first embodiment of the present invention. The cup assembly includes a paper sleeve 10 located in a paper sleeve 2. The paper sleeve 10 may be made of PE-coated paper. The paper sleeve 10 includes a paper sleeve 10 and a paper bottom element 18. The paper sleeve 10 is formed with a lower edge 11 and an upper edge 12. The 10 lower edge 11 of the paper sleeve 10 is an internally retroflex edge engaged with a bent edge of the paper bottom element 18, thus securing the paper sleeve 10 to the paper bottom element 18. A plastic mouthpiece 13 is provided on the upper edge 12 of the paper sleeve 10. The plastic mouthpiece 13 is directly provided on the upper edge 15 12 of the paper sleeve 10 without having to roll the upper edge 12 of the paper sleeve 10 beforehand. Several plastic bosses 14 are formed on the paper sleeve 10 near the upper edge 12. The plastic mouthpiece 13 and the plastic bosses 14 may be made of a conventional plastic material, a biodegradable plastic material or a bio-plastic material. The plastic mouthpiece 13 and the 20 plastic bosses 14 are provided on the paper sleeve 10 by plastic injection molding, hot pressing, high-frequency waves or ultrasonic waves. The plastic mouthpiece 13 and the plastic bosses 14 are preferably made one. The paper sleeve 2 is made with a lower edge 23 and an upper edge 25. The paper sleeve 2 is provided around the paper sleeve 10, with an insulating 25 space 21 defined between the paper sleeve 2 and the paper sleeve 10. An upper portion of an internal side of the paper sleeve 2 is in contact with the 5 plastic bosses 14. Thus, the thickness of the plastic bosses 14 becomes the thickness of the upper portion of the insulating space 21. Therefore, the thickness of the insulating space 21 is adequate near the upper edge 12 of the paper sleeve 10 and the upper edge 25 of the paper sleeve 2. The insulating 5 effect of the insulating space 21 is good. Moreover, the rigidity of the paper assembly is good. Referring to FIG. 4, there is shown a cup assembly in accordance with a second embodiment of the present invention. The second embodiment is identical to the first embodiment except providing a plastic ring 22 between the 10 paper sleeves 10 and 2 near the lower edges 11 and 23 of the paper sleeves 10 and 2. Thus, the thickness of the plastic ring 22 becomes the thickness of the lower portion of the insulating space 21. That is, the thickness of the lower portion of the insulating space 21 is adequate. As described above, the thickness of the upper portion of the insulating space 21 is adequate. Hence, 15 the thickness of the insulating space 21 is adequate and constant from top to bottom. The plastic ring 22 is provided by adhesion or hot melting. Referring to FIG. 5, there is shown a cup assembly in accordance with a third embodiment of the present invention. The third embodiment is like the first embodiment except that the lower edge 23 of the paper sleeve 2 is an 20 internally retroflex edge. The lower edge 23 of the paper sleeve 2 is in contact with the paper sleeve 10. Thus, the thickness of the lower portion of the insulating space 21 is adequate. As described above, the thickness of the upper portion of the insulating space 21 is adequate. Hence, the thickness of the insulating space 21 is adequate and constant from top to bottom. 25 Referring to FIG. 6, there is shown a cup assembly in accordance with a fourth embodiment of the present invention. The fourth embodiment is like 6 the first embodiment except two things. At first, the lower edge 11 of the paper sleeve 10 is a straight edge, not an internally retroflex edge. Hence, the paper sleeve 10 is like the paper sleeve 2 but smaller. Secondly, there is provided a plastic bottom element 19 instead of the paper bottom element 18. 5 The plastic bottom element 19 includes two annular grooves 15 defined in an upper face. The lower edge 11 of the paper sleeve 10 is fit in one of the annular grooves 15 while the lower edge 23 of the paper sleeve 2 is fit in the other annular groove 15. Thus, the thickness of the lower portion of the insulating space 21 is adequate. As described above, the thickness of the 10 upper portion of the insulating space 21 is adequate. Therefore, the thickness of the insulating space 21 is adequate and constant from top to bottom. The plastic bottom element 19 is connected to the paper sleeves 10 and 2 by injection molding of a conventional plastic material, a biodegradable plastic material or a bio-plastic material. 15 Referring to FIG. 7, there is shown a cup assembly in accordance with a fifth embodiment of the present invention. The fifth embodiment is identical to the first embodiment except including an annular plastic lip 16 extending from the plastic mouthpiece 13. The annular plastic lip 16 is separated from the plastic bosses 14 by an annular gap 17 for receiving the upper edge 25 of the 20 paper sleeve 2. The plastic mouthpiece 13, the plastic bosses 14 and the annular plastic 16 may be provided on the upper edges 12 and 25 of the paper sleeves 10 and 2 by injection molding, hot pressing, high frequency waves or ultrasonic waves. The plastic mouthpiece 13, the plastic bosses 14 and the annular plastic 16 may be made of a conventional plastic material, a 25 biodegradable plastic material or a bio-plastic material. The plastic mouthpiece 13, the plastic bosses 14 and the annular lip 16 are preferably 7 made one. Referring to FIG. 8, there is shown a cup assembly in accordance with a sixth embodiment of the present invention. The sixth embodiment is like the embodiment except including a thermal foaming layer 24 sandwiched between 5 the paper sleeves 10 and 2. When a hot drink is contained in the paper cup 1, heat is transferred to the thermal foaming layer 24 from the paper sleeve 10 so that the thermal foaming layer 24 foams to improve the insulating effect. The thermal foaming layer 24 does not affect or blur any pattern provided on an external side of the paper sleeve 2 because the thermal foaming layer 24 is not 10 in contact with the external side of the paper sleeve 2. As discussed above, the cup assembly exhibits several advantages. At first, the cup assembly provides a good insulating effect since the thickness of at least the upper portion of the insulating space 21 is adequate. Secondly, the cup assembly is inexpensive because the plastic mouthpiece 13 is 15 provided on the upper edge 12 of the paper sleeve 10 by injection molding, hot pressing, high frequency waves or ultrasonic waves. The present invention has been described via the detailed illustration of the embodiments. Those skilled in the art can derive variations from the embodiments without departing from the scope of the present invention. 20 Therefore, the embodiments shall not limit the scope of the present invention defined in the claims. 8