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
Inventor
A. Doster Henry
D. Swartz Alden
Zelnick Charles
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.)
Lufkin Rule Co
Original Assignee
Lufkin Rule Co
Publication date
Application grantedgrantedCritical
Publication of CA721905ApublicationCriticalpatent/CA721905A/en