Abstract:
A one-piece plastic drum is formed with a top, bottom and sidewall. The top is profiled to form a sump around an access opening so that when the drum is turned upside down, all the liquids are dispensed from the drum.

Description:
BACKGROUND OF THE INVENTION 
     A. Field of Invention 
     This invention relates to a unitary plastic drum for shipping and storing various materials, and more specifically to a plastic drum for liquid materials, which drum has a sloping top with a sump formed about the drum open holes so that all the liquid can be removed out efficiently. 
     B. Description of the Prior Art 
     Plastic drums are used frequently to ship and store various materials. These types of drums are preferred over metal drums because they are simpler and cheaper to make, easier to handle, and weigh less. Frequently, plastic drums are used to ship liquid materials used in agriculture, or the chemical industry which are highly concentrated and therefore, must be diluted. Since these liquids are very expensive, it is important that all the contents of the drum be removed before the drum is discarded or returned, to eliminate waste. Frequently, a plastic drum is emptied by turning it upside down. However, until now plastic drums were shaped so that it was impossible to empty their contents 100%. 
     Hence, there is a great need in the art for a plastic drum which could be emptied efficiently or by turning it upside down. 
     OBJECTIVES AND SUMMARY OF THE INVENTION 
     In view of the above-mentioned disadvantages of the prior art, it is an objective of the present invention to provide a plastic drum which can be efficiently emptied by turning it over. 
     Yet a further objective is to provide a plastic drum which can be made efficiently and economically for example by blow molding. 
     Another objective of the invention is to provide a drum which can be emptied efficiently using standard equipment. 
     Other objectives and advantages of the invention shall become apparent from the following description of the invention. Briefly, a plastic drum constructed in accordance with this invention consists of a substantially cylindrical plastic body having a straight cylindrical side, a top and a bottom. At least one access hole is provided on the top for filling and emptying the drum. The top is profiled or contoured to form a sump which is concentrically disposed around the access hole whereby as the drum is turned over, all the liquid collects in the sump and then it runs out through the access hole. The drum is originally formed with a top and a bottom chime for protection as well as to insure that the drum stands upright or vertical when resting on a horizontal surface, and ease of handling. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows an elevational view of a drum constructed in accordance with this invention; 
     FIG. 2 with a closure caps applied shows a top view of the drum with closure caps removed; 
     FIG. 3 shows a partial cross sectional view of the drum turned upside down taken along lines 3--3 in FIG. 2; and 
     FIG. 4 shows a partial section orthogonal view of one of the openings for inside the drum. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, a drum 10 constructed in accordance with this invention consists of a top 12, a bottom 14 and a substantially cylindrical sidewall 16. Sidewall 16 is formed with two rings 18, 20 provided substantially equidistant from the top 12 and bottom 14 respectively to allow the drum to be rolled on the ground and to reinforce the sidewall 16. At the top 12, the drum 10 is provided with a narrow neck 22 and a chime 24 which permits the handling of the drum by mechanical means such as a parrot-beak, or forklift handling. 
     As seen more clearly in FIG. 2, top 12 is provided with two access holes 26, 28 disposed at a predetermined distance from the longitudinal axis of the drum. The structure of the top surrounding these holes is substantially identical. Except as described below, inner surface 30 of the top 12 is relatively smooth and is pitched toward one of the openings 16, or 18. Starting from chime 24 two raised portions 32, 34 extend toward and join a raised ring 36. A cylindrical relatively thin wall 38 rises straight up from the ring 36 to form a mouth for the drum. The wall 38 has a radial ledge 40 which forms the top of threads 42 (seen in FIG. 3 and 4) disposed helically around the inside of wall 38. 
     As seen more clearly in FIG. 4, when the drum is turned upside down, portions 32, 34 form on the inside surface of the top 12 two corresponding channels 44, 46 separated by a ramp 48. Moreover, the inner surface of the top is profiled under ring 36 with two arcuate zones 50, 52 disposed below the level of the channels and forming with channels 44, 46 a two-tiered sump for the drum. 
     Finally a spine 54 is provided on the inner surface 30 between the two openings for reinforcement. 
     The drum constructed as described above is used as follows; The drum is placed in the upright position shown in FIG. 1, and is filled with a liquid material such as a herbicide or a pesticide through one of the openings, such as 16. The other opening, 18, is left open for venting. After the drum 10 has been filled, both opening are closed by standard caps 38 which may be secured to the respective opening by engaging internal threads 42. 
     In order to dispense the liquid from the drum, its caps 38 are removed and the drum is turned upside down to allow the liquid to flow out through either or both openings 26, 28. Importantly, as the drum empties, drops of the fluid run down inside sidewall 16 and because of the profiled top surface 30, they are collected into the sumps formed therein by the channels 44, 46 and arcuate zones 50, 52 and flow out of the openings. In this manner, and because the drum has no crevices or holes in which the fluid can remain as the drum is in its upside down position, all the fluid can be safetly and economically removed from the drum. The drum can then be returned for reuse as is, or can be melted down and recycled. 
     Preferably the drum is a one piece drum made for example by blow molding. 
     Obviously, numerous modifications may be made to this invention without departing from its scope as defined in the appended claims.