Hydraulic jar lock
AssigneeNational-Oilwell, L.P.
InventorsJames R. Streater, Donald L. Leach
Life of this patent
Estimating the term…
Abstract
An internal, positive engagement lock that locks a tool, such as a hydraulic drilling jar, in the fully open position when the tool is racked back and when tripping in and out of the hole close to the surface. The lock mechanism is spring biased into a locked position that provides a positive engagement between two axially translatable components, thus preventing any actuation of the tool. As the tool is run in the hole, increasing hydrostatic pressure within the tool will cause the locking mechanism to shift to a disengaged position and the tool will operate normally. The spring-biased locking mechanism will return to the locked position as hydrostatic pressure decreases as the tool is retrieved to the surface.
Claims30
A locking apparatus comprising:
- an outer body;
- a sleeve slidably disposed within said outer body;
- a annular cavity formed between said outer body and said sleeve;
- a piston sealingly engaging said cavity;
- a plurality of lock segments connected to said piston, wherein said lock segments have a first position preventing said sleeve from axially translating in at least one direction relative to said outer body and a second position allowing axial translation;
- and
- a spring disposed within said cavity so as to bias said piston and lock segments to the first position, wherein said lock segments are moved to the second position by pressure within said outer body.
A downhole tool comprising:
- a body:
- a sleeve disposed within said body and axially translatable relative to said body:
- a locking mechanism having a locked position preventing axial translation of said sleeve relative to said body, wherein said locking mechanism comprises a piston disposed in a cavity formed by said body and said sleeve, and wherein said piston sealingly engages the cavity and the cavity is maintained at ambient pressure;
- and
- a spring biasing said locking mechanism to the locked position, wherein said locking mechanism is unlocked by hydrostatic pressure within said tool.
A downhole tool comprising:
- a body:
- a sleeve disposed within said body and axially translatable relative to said body;
- a locking mechanism having a locked position preventing axial translation of said sleeve relative to said body, wherein said locking mechanism comprises a piston disposed in a cavity formed by said body and said sleeve, and wherein said locking mechanism comprises a plurality of lock segments connected to said piston;
- and
- a spring biasing said locking mechanism to the locked position, wherein said locking mechanism is unlocked by hydrostatic pressure within said tool.
A downhole tool comprising:
- a body:
- a sleeve disposed within said body and axially translatable relative to said body;
- a locking mechanism having a locked position preventing axial translation of said sleeve relative to said body;
- and
- a spring biasing said locking mechanism to the locked position, wherein said spring comprises a plurality of belleville springs, and wherein said locking mechanism is unlocked by hydrostatic pressure within said tool.
A tool comprising:
- a drilling jar comprising an outer body and an inner sleeve that translates axially relative to the outer body;
- and
- a locking mechanism disposed on said drilling jar and having a locked position preventing the axial translation of the inner sleeve in at least one direction and an unlocked position where axial translation is allowed, wherein said locking mechanism comprises a spring that biases said locking mechanism to the locked position and a piston that moves said locking mechanism to the unlocked position in response to pressure within said drilling jar.
A drilling jar comprising:
- a cylindrical body having and inner surface;
- a sleeve slidably disposed within said cylindrical body and having an outer surface;
- an annular chamber formed by the inner surface of said cylindrical body and the outer surface of said sleeve;
- a piston slidably disposed in said annular chamber and sealingly engaging the inner surface of said cylindrical body and the outer surface of said sleeve, wherein said piston has first and second ends;
- a plurality of apertures in said piston and including openings to the second end;
- a plurality of lock segments having an interface portion adapted to engage said apertures and an extending portion comprising a locking head;
- a spring disposed within said chamber and adapted to provide a force to the first end of said piston so as to bias said piston to a locked position wherein the locking heads of said plurality of lock segments prevent said sleeve from sliding relative to said body in one direction.
Dependencies are inferred from the claim text.