Patent ID: 7685714

Claim:
A process for producing catalytic converters for an internal combustion engine exhaust system, the converter having interior and exterior surfaces, using a transfer press capable of being repetitively operated in press cycles comprising a stroke and a transfer interval, each said catalytic converter comprising: a. a single-piece, seamless metallic housing formed from a preform having a first end and a second end; b. a tubulated gas inlet port in said housing through which exhaust gas is introduced; c. a tubulated gas outlet port in said housing through which said exhaust gas is discharged; d. a tubulated intermediate section of said housing connecting said gas inlet port and said gas outlet port; e. an inlet transition section connecting said inlet port and said inlet end of said intermediate section; f. an outlet transition section connecting said outlet end of said intermediate section and said outlet port; and g. at least one catalytic element contained within said intermediate section and through which said exhaust gas passes when flowing between said gas inlet port and said gas outlet port; the interior surfaces of said inlet and outlet transition sections and said gas inlet and outlet ports having been swaged and being substantially free from ridges thereon; and said transfer press comprising an ordered sequence of swaging stations sequentially enumerated from “1” to n, having a value of at least 2, each of said swaging stations comprising a die set, and said die sets being adapted to a carry out in sequence a plurality of “n” graduated swaging steps that collectively swage each of said preforms at said first end to form said gas inlet port and said inlet transition section and at said second end to form said gas outlet port and said outlet transition section such that there is created in said perform a reduced diameter section, and wherein said process comprises: inserting at least one catalytic element into each of said preforms; an initiation operation wherein one of said preforms with said at least one catalytic element is disposed in each of said swaging stations to prepare said press to be activated to simultaneously carry out said swaging steps in all of said swaging stations, and thereafter repetitively operating said press in said press cycles such that, during each said stroke is accomplished the step of: i. actuating said transfer press to simultaneously carry out said swaging steps in all of said swaging stations, and during each said transfer interval are accomplished the steps of: ii. providing one of said seamless metallic tube preforms having said at least one catalytic element inserted therein; iii. situating said preform in said first swaging station; iv. removing a finished converter from said final swaging station; and v. transferring a partially swaged preform from each of said stations “1” to “n−1” to the succeeding swaging station.