this is the ORIGINAL "BUTTERBALL" PATENT APPLICATION by Ada Walker in 1939 from whom Leo Peters bought the rights to the name & used for his BOUTIQUE BUTTER (which is also used by McDonalds for the hotcake breakfast) .
Butterball Farms in Grand Rapids MI continues to sell the butter and uses the name Butterball, but it is more commonly associated with the Butterball Turkey who purchased the rights to use the name from Leo Peters, but a deal was made that Peters could continue forever to use the name with his butter.
see attached or see
http://tsdr.uspto.gov/documentviewer?caseId=sn71423319&docId=ORC20051101235008#docIndex=0&page=1 