The present invention relates generally to the manufacture of metallic containers, and more particularly to an integrated machine station for forming cans from metallic blanks and trimming and cleaning them.
Many different methods and apparatus for manufacturing metallic containers such as cans have long been known. In past years cans were typically of the "three piece" variety, i.e., a sidewall, and two separate end members. Such cans were formed by rolling flat stock into a hollow cylinder, forming and sealing an axial seam, applying and seaming a bottom end, then filling the container and applying a top. In recent years more and more cans of the drawn and ironed variety have been produced. Cans of this type are formed by drawing a disk-like blank into a shallow cup, then forcing the cup through a set of annular dies of decreasing diameter so that the cup is stretched and deepened to form a can. The lip about the open end of the can is typically irregular and ragged, and accordingly must be trimmed to form a regular upper edge, simultaneously sizing the height of the can. Finally, metal particles, lubricants and other foreign matter must be removed from the cans before printing or filling, and accordingly such cans are typically transported through elongate chambers where they are washed, rinsed with deionized water or the like, then dried and finally printed.
Despite advances in apparatus for forming the cans, such as for instance the draw-and-ironing machine disclosed in U.S. Pat. No. 4,007,620 issued Feb. 15, 1977, transportation of cans from one stage to another has continued to be a problem. In fact, more cans are damaged during transfer than during the actual processing or manufacturing operations. Although conveyors per se have been improved and newer forms thereof introduced, the basic approach to transporting numerous small articles, such as cans, has remained substantially the same. Cans produced by one stage are accumulated upon a conveyor, and fed to a subsequent stage. Each conveyor commonly provided buffering areas wherein cans could be accumulated in the event that a preceding stage produced more than could be accommodated by a succeeding stage. Such buffering areas absorb valuable floor space, necessarily increasing the overall size of the requisite manufacturing areas and moreover increasing the likelihood of damage to the cans.
Further, the apparatus used for cleaning newly-manufactured cans has typically taken the form of a tunnel-like flow through system wherein cans are transported through an elongate zone wherein they are progressively washed, and then dried. Conveyors having buffering areas are typically associated with either or both ends of the cleaning stage, further adding to the amount of space occupied by the apparatus.
From the foregoing, it will be understood that it would be highly advantageous to provide a unitized system for manufacturing cans, which eliminates the deficiencies of the usual prior art arrangements.
It is accordingly an object of the present invention to provide a unitized work station for manufacturing drawn and ironed can bodies.
Another object is to provide means for manufacturing cans, which occupies significantly less floor space than prior art apparatus.
Still another object is to provide a compact washer-dryer stage which may be used in direct juxtaposition with other manufacturing apparatus.
Another object is to provide a unitized can manufacturing station including a cleaning stage arranged in vertical tiers.
Yet another object is to provide a method of manufacturing metal cans which optimizes available floor space.