Method of making liquid-tight cup

Abstract

A method of forming a liquid-tight up comprising a cup-like body and a sheet member disposed around the peripheral surface of the cup-like body, with the sheet member being corrugated to provide a plurality of concavo-convex flutes, whereby air compartments are provided between the peripheral surface of the cup-like member and the inner surface of the sheet member, comprises forming the sheet member by cutting, from a planar sheet, a planar blank having a width in excess of the peripheral length of the circular bottom of an inner cup member and a length substantially equal to the height of the side wall of the inner cup member. The opposite ends of the planar blank are then united in overlapped relation to form a circular cross-section sleeve constituting an outer member and, after such uniting, the blank is formed with concavo-convex flutes to form a structure whose peripheral surface is corrugated. The inner and outer members are then telescoped to form a composite liquid-tight cup with heat insulating air passages extending upwardly along the outer surface of the side wall of the inner cup member.

Description

BACKGROUND OF THE INVENTION

This invention relates to a method of making a cup for containing liquid, such as, cooling drinks, hot tea, etc, solids, and a combination of liquid and solids. Various kinds of cups made of paper or plastics have been provided heretofore. However, prior cups have been required to have a high heat retaining property or a high thermal insulating property to ensure that a user can handle the cup without feeling the heat of contents therein and being wetted with water drops on the peripheral surface thereof, even when the cup contains a cooling drink, hot tea, etc.

SUMMARY OF THE INVENTION

It is a primary object of this invention to provide a method of making a liquid-tight cup which has enough heat retaining property or enough thermal insulating property so that, even when the vessel contains a cold or hot drink, no water drops are developed on the outer surface of the cup and limited heat is allowed to transfer through the walls of the cup to a user.

It is a further object of this invention to provide a method of making a nearly liquid-tight cup of a plain design which creates an aesthetic feeling through the sense of sight.

It is a still further object of this invention to provide a method of making a liquid-tight cup which is of multi-wall construction providing enough strength for the cup.

These and other objects of this invention are accomplished in accordance with the teachings of this invention by providing a liquid-tight cup comprising an inner hollow bottomed member, and an outer member circumferentially covering at least part of the longitudinal length of the peripheral surface of the inner member, the outer member being formed with a plurality of concavo-convex flutes each extending longitudinally over the length thereof, whereby a plurality of air compartments are provided between the inner and outer members. The air compartments can impart enough heat retaining property and enough thermal insulating property to the cup.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects of this invention will become more apparent when considered in view of the following description and drawings in which:

FIG. 1 is a perspective view of an embodiment of a cup constructed according to the teachings of this invention;

FIGS. 2 to 4 are perspective views explaining different methods of making a corrugated sheet, which is to be disposed around the cup body;

FIGS. 5 and 6 are perspective views of different embodiments of the cup having the corrugated sheet of FIG. 4 attached therearound in different manners;

FIGS. 7 and 8 are perspective views explaining further methods of making a corrugated sheet; and

FIGS. 9 and 10 are perspective views of further different embodiments of the cup.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawings and in particular to FIG. 1, there is shown a typical liquid-tight cup consisting of a hollow bottomed body 1 of a cup-like shape and forming an inner member, and a covering or outer member 2 disposed around the outer surface of the hollow bottomed body 1. The covering member 2 is provided with a plurality of concavo-convex flutes 3 extending along the height of the body 1 so that a plurality of air compartments 4 are provided over the circumference of the hollow body 1 and between the outer surface of the hollow body 1 and the inner surface of the covering member 2. The hollow body and the covering member may be made of suitable materials, such as, water- and oil-resistant paper, plastics, foil metals, or combinations thereof. However, paper is preferably employed as a material for the making of the cup, because a paper cup is inexpensive to manufacture and the disposal of the used cup is carried out with ease.

It is noted that the air compartments 4 impart a suitable heat retaining property and a suitable thermal insulating property to the cup. Therefore, even where the cup contains a cold liquid, no water drops are developed on the outer surface of the cup and the hands of a user don't become wet. In contrast, when the cup contains a hot liquid, he can hold the cup without feeling the heat of the hot liquid.

The disposing of the corrugated covering member 2 around the hollow body 1 can be selectively effected by the following methods. In the first method, the corrugated sheet member 2 is preliminarily formed into a hollow conical frustum or a cylinder with the opposite side ends thereof secured to each other and thereafter the frustumshaped or cylindrical cup body 1 is inserted into the complementary covering member 2. The members 1 and 2 may be preferably stuck together by using a paste or by heat sealing or other means. This method is hereinafter referred to as the "inserting method". Secondly, the disposing of the corrugated covering member 2 is accomplished by directly winding the corrugated covering member 2 around the hollow body 1. In this case, the corrugated covering member 2 may be connected to the hollow body 1 by providing the peripheral surface of the hollow body 1 with a paste in a circumferential line or lines. The second methid is hereinafter referred to as the "winding method".

In FIG. 2, a rectangular base sheet A is shown formed with the plurality of concavo-convex flutes 3 arranged in parallel with each other and with the opposite side ends of the base sheet A. The base sheet A is trimmed by cutting into a rectangular sheet member 2a having such dimensions that the height or the length of the flutes 3 of the sheet member 2a equals the longitudinal length of the hollow body 1 and the width is slightly greater than the circumferential length of the bottom of the hollow body 1. In addition, it is of course necessary that, in the case where the sheet member 2a is to be connected to the hollow body 1 with its opposite side ends overlapped together, the sheet member 2a is to be increased in width by about twice the overlapped length of the opposite side end.

In case where the rectangular sheet member 2a of FIG. 2 is to be disposed around the hollow body 1 of a conical frustum shape by the inserting method, the sheet member 2a is first deformed into a cylinder with the opposite side ends stuck together and then the hollow body 1 is inserted into the thus formed cylinder of the sheet member 2a. Since the circumferential length of the upper portion of the hollow body 1 is greater than the width of the sheet member 2a before the deformation, the upper portion of the cylinder 2a is expanded when the hollow body 1 is inserted thereinto whereas the lower portion of the cylinder 2a is shrunk by the influence of the expansion of the upper cylinder portion, allowing the cylinder 2a to be snugly fitted onto the hollow body 1. However, to precisely cut the once corrugated base sheet A into a given size of covering member 2a is very difficult because of the flexibility and the elasticity of the corrugated base sheet A. Also, there occurs a difficulty in that, when sticking the opposite side ends of the covering member 2a together, it is required to coincide the convex or concave surface of one of the opposite side ends of the covering member 2a with the concave or convex surface of the other side end.

In order to eliminate the above difficulty, it is preferable to previously form a base sheet, initially without concavo-convex flutes, into a corrugated cylinder in a manner as follows. In FIG. 3, a smooth base sheet B.sub.1 is cut to form a smooth rectangular sheet B.sub.2 which is, in turn, easily connected together at the opposite side ends thereof into a smooth cylinder B.sub.3 on which a plurality of parallel concavo-convex flutes are marked in a suitable manner, thus forming a corrugated cylinder 2a'. The cup is completed, in the inserting method, by inserting the hollow body 1 into the corrugated cylinder 2a' or vice versa.

FIG. 4 shows a modified covering member 2b of a sector shape which may be formed by stamping out of the corrugated base sheet A. The covering member 2b has a plurality of concavo-convex flutes 3 parallel with one another and with a radial center line of the sector 2b passing through a common center of curvature of the sector arcs.

FIGS. 5 and 6 show cups obtained by using the sector 2b of FIG. 4. It is noted that the cup of FIG. 5 having the sector 2b disposed therearound with the opposite side ends of the sector overlapped is bulky since the direction of inclination of each flute of one of the opposite side ends reverses with respect to that of each flute of the other opposite side end at the connection of the sector. Therefore, the making of the cup is preferably performed by the winding method, in which the sector 2b is wound around the hollow body 1 without sticking the opposite side ends thereof with each other, as shown in FIG. 6.

FIG. 7 shows a further modified covering member 2c of a sector shape which may be formed by stamping, out of the smooth base sheet B.sub.1 of FIG. 3, a smooth sector sheet B.sub.4 and marking a plurality of radially extending concavo-convex flutes 3 on the sector sheet B.sub.4. With the covering member 2c having the radially extending concavo-convex flutes 3, the flutes at the opposite side ends are made parallel to each other when disposed around the hollow body 1, providing a good figure of liquid-tight cup as shown in FIG. 1.

FIG. 8 shows a laminated covering member 2d, which is a modification of the sector 2b shown in FIG. 4. The modified sheet 2d is formed by stamping out a sector from a sheet C, which sheet C is a lamination of the smooth base sheet or film B.sub.1 and the corrugated base sheet A. The thus produced covering member 2d is preferably disposed around the conical body 1 in the manner as mentioned regarding the sector sheet 2b of FIG. 3, with placing of the smooth surface of the covering member 2d outside the vessel. The covering member 2d, however, may be disposed around the conical body with the corrugated surface out.

FIGS. 9 and 10 show different embodiments, in which a corrugated sheet is disposed around only part of the conical body 1.

It is stated again that the hereinbefore described cup members can be made of any of such materials as paper, plastics, foil metals and combinations thereof. Particularly, paper is preferably employed in view of the low manufacturing cost and the easiness of used cup disposal. It is also stated that when the plastics are employed the cup may be of one-piece integral formation.

From the foregoing, it will be understood that the cup according to the invention has the air compartments formed therein along the length of a cup so that the thermal insulating property or a heat retaining property are imparted to the cup, with the resultant advantages that the user feels no heat of the contents in the cup and no water drops are developed on the peripheral surface of the cup even when it contains a cold liquid, a solid, or a combination thereof. It is a further advantage of this invention that the cup has sufficient strength since it is of multi-wall construction.

Although various specific embodiments have been described above, it will be readily understood by those skilled in the art that various modifications and changes in the details of constructions may be accomplished without departing from the spirit and scope of the invention. For example, the cross section of the flutes of the corrugated sheet may be of any shape such, for example, as U- or V-shape. It is also possible to further provide the peripheral surfaces of the cups shown in FIGS. 1, 5, 6, 9 and 10 with a smooth sheet, instead of using the laminated sheet 2d.

Claims

What I claim is:

1. A method of forming a liquid-tight heat-insulated cup comprising the steps of providing a smooth surface inner cup member having a circular bottom and a circular cross-section side wall in liquid-tight relation with said bottom and extending upwardly therefrom; cutting, from a smooth planar sheet, a smooth planar blank, as a starting material, having a width in excess of the peripheral length of said circular bottom and a length substantially equal to the height of said side wall; then uniting the laterally opposite ends of said smooth planar blank in overlapped relation to form a circular cross-section, initially smooth surface, sleeve constituting an outer cup member; after such uniting, thereafter forming parallel, longitudinally extending concavo-convex flutes in said outer cup member to form a structure whose peripheral surface is corrugated longitudinally of said sleeve; and then telescoping said inner cup member into said outer cup member to form a composite liquid-tight cup with heat insulating air passages extending upwardly along the outer surface of the smooth side wall of said inner cup member.