Method and apparatus for restoring tubular upsets
Patent 4676528 Issued on June 30, 1987. Estimated Expiration Date: 
April 29, 2006. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
April 29, 2006. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInventorApplicationNo. 06/856981 filed on 04/29/1986US Classes:285/15, REPAIR285/288.8, Having crack arresting feature285/334Flat crestExaminersPrimary: Kundrat, Andrew V.Assistant: Knight, Anthony Attorney, Agent or FirmInternational ClassesE21B 17/042 (20060101)E21B 17/02 (20060101) AbstractA tubular upset extension apparatus which prolongs the usefulness of upsetted tubing joints used in drilling oil, gas and water well bore holes. The upset extension apparatus is fitted onto hollow bore tubing having shortened and specially threaded box and pin joints and a beveled peripheral shoulder at the inner terminal of the threads. The upset extension apparatus likewise has a hollow bore and specially threaded male and female ends which are rotatably engageable with the shortened tubing upsets. An exterior, non-bore penetrating circumferential groove is defined by the point of intersection of the shoulders of the upset extension and the shortened tubing upset. The circumferential groove receives a cosmetic weld, non-thread and non-bore penetrating weld which rigidly secures the upset extension to the shortened upset and maintains the internal and external integrity of the engaged sections.Other References
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