The only Alfons Jacober I know of is the brother of my grandfather who was born in Alsace in 1877 (Alsace was part of Germany at that time)and died in Germany in 1915 during the first world war. He was a sculptor and cutter of stones in Altkirch (Alsace). He didn't go to the US but his son René did. The Alfons Jacober you are looking for is probably issued from another branch of the family whose origins are in Switzerland. However some members of the family migrated to Germany in the 17th and 18th centuries. If I happen to get more about your ancestor I'll let you know.