Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA724568A
Inventor
E. Severson Donald
S. Gleason David
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STATE UNIVERSITY AND SCHOOL OF MINES
Great Northern Railways Co
University of North Dakota UND
Original Assignee
STATE UNIVERSITY AND SCHOOL OF MINES
Great Northern Railways Co
University of North Dakota UND
Publication date
Application grantedgrantedCritical
Publication of CA724568ApublicationCriticalpatent/CA724568A/en