Patent ID: 8418758
Filing Date: 2013-04-16
Classification: E21B,Y10T

Abstract:
1. A jarring tool comprising: a segment of sub housing containing an upper stop proximate a first end thereof; an outer latch piece connected to an upper end of the lower shaft inside the sub housing; an upper shaft passing through the stop and connecting on a first end thereof to an inner latch piece; a cap on a second end of the upper shaft retaining a washer stack against the upper stop; and a two-piece retainer inside the sub housing, the retainer having a first piece providing a restraining region and an open region and a second piece attached to the sub housing and to the first piece; wherein the retainer retains the inner and outer latch pieces in a latched position in the restraining region until the latch pieces are displaced toward the second end of the sub housing through the retainer to the open region as a result of a tensile force on the outer latch piece.