1.  Field of the Invention
The present invention relates to a vessel having a vessel body formed of metal and including an approximately cylindrical wall, a bottom and a cover, and a plastic ring provided at each of opposite ends of the vessel body and extending radially beyond the vessel body. 
2.  Description of the Prior Art
Such vessels, which are used, e.g., for receiving beverages, have a body formed of a special steel and generally well known.  A vessel of this type is described, e.g., in a British Publication GB-A-2,001,032.  In the vessel described in the British Publication, both the base and the top rings are formed as massive, plastic rings and are rather expensive.  One of the rings (the base ring) serves for supporting the vessel, with the other ring insuring convenient handling of the vessel, being provided to this end with a gripping opening.  On the other hand, the two rings serve for protecting the vessel body from deformation.  The danger of the deformation of the vessel body is particularly large when during loading or transportation of the vessels, the vessel is displaced downwardly along a loading platform in an inclined position and is, therefore, subject to a one-sided shock load.  The forces, which in this case act on the vessel, are so large that they crash the vessel body because of the deformation of the respective ring, and the vessel becomes unusable as the vessel volume is not insured.  The used plastic rings are not capable of withstanding or absorbing the acting forces and transmit them, as a result of their deformation, directly to the vessel body. 
A high resistance of the vessel body to the deformation is achieved in the vessel disclosed in German Publication DE-A-39 37 085.  In the vessel described in the German Publication bottom-side and cover-side rings or rims are formed of a polymer material, and metallic parts are secured at the vessel body ends.  The metallic additional parts have at least one connection surface formed as a ring to which a tooth plate is attached the teeth of which are so inclined toward the ring that the teeth ends extend toward the bottom or the cover and are attached to the bottom or the cover.  This variation of a vessel is characterized by a large expenditure of material and by high manufacturing costs.  In addition, gaps are formed at the free ends of the metallic parts which create, in case of dirt accumulation, a danger of gap corrosion under action of moisture. 
Accordingly, an object of the present invention is to provide a vessel of the above-described type devoid of the above-discussed drawbacks. 
Another object of the present invention is to provide a vessel of the above-described type which insures an improved protection of the vessel body from deformation in case of a fall and/or when the vessel is subjected to a shock load. 
A further object of the present invention is to provide a vessel of the above-described type which can be easily cleaned and can be economically produced. 
These and other objects of the present invention, which will become apparent hereinafter, are achieved by providing a vessel in which at least one of the plastic rings includes a flange ring, an arc-shaped ring abutting a section of the vessel body, and an intermediate ring which connects the flange ring with the shaped ring and has a reduced size waist-like portion.  The present invention proceeds from a premise that the relatively formstable flange region of the vessel body, together with the adjoining ring section, forms a rigid sandwich unit, with the rigid flange ring section, which is connected with the remaining portion of the ring by the intermediate ring section, absorbing the axial or partially axial forces.  The fall energy of the vessel is converted into the deformation energy as a result of the elastic deformation of the intermediate and flange rings, which form sections of the respective plastic ring, without the bond of the shaped ring with the vessel body transmitting deformation to the bottom or cover. 
In this way, damage of the vessel body is prevented.  The bottom ring has a rather compact flange ring, whereas the flange ring of the top ring has an increased length such that the upper edge of the flange ring extends past the inlet nipple, with the height of the tubular extension being such that a gripping opening can be provided, on one hand, and on the other hand, a sufficient surface remains for inscriptions indicating the characteristics of the vessel, ownership, etc. . . .  Because the tubular extension provides for an additional increased stability of the flange ring of the top ring, its wall thickness up to its lower edge, which serves as a snap and stop edge, can be reduced, without reducing the capacity of the top ring to absorb the deformation energy.  The diameters of the flange ring of the base and top rings and their staggering are so adapted to each other that a reliable stacking of the vessels having the same shape is insured.  The reliable stacking is also possible with the vessels having different shapes but the same diameters.  The stacking of vessels of different shapes is also possible by formation of shorter ribs on the inner surface of the base ring.  In order to optimize application of forces to sections of the base and top rings adjacent to the vessel body, it is proposed to form a transition region between the intermediate ring and the shaped ring which is closest to the vehicle body, as an arcuate region. 
Pressure peaks and deformation of the portions of the base and top rings adjacent to the vehicle body, in the region of the bottom and cover caps, which are susceptible to bending, are prevented by having the thickness of the base and top rings reduced in the respective regions of the rings to a minimum, with the rings having in the respective regions an elastic profile.  According to advantageous embodiment of the present invention, the base and top rings are formed of a thermoplastic material.  This material has good shock and tear resistance, is easily recycled, and, e.g., can be easily colored in different colors.  Parts from this material can be easily and economically produced by insection molding.  The base and top rings are secured on the vessel body by an elastic snap engagement of the retaining rings, which are provided on the shaped rings, in the grooves formed on the vessel body.  In order to achieve a very strong rigidity of the connections, it is further proposed to glue the base and top rings to the vessel body. 
In accordance with a further development of the present invention, the top ring is provided with a pocket, which is easily deformable in the axial direction for snap pin connection with a logistic element, e.g., a transponder.