Deep well drilling jar

Claim 2

In a deep well drilling jar, the combination of: internal and external tubular mandrels telescopically related; means for connecting the top end of one mandrel to a drill string and the bottom end of the other mandrel to a drill; a jarring device embodied within said mandrels including delayed action means for striking an upward blow on the mandrel connected to said drill, said means also limiting said telescopic movement; a spline device embodied within said mandrels including male splines formed oN said internal mandrel and intermeshing female splines formed on said external mandrel; and a spline retraction device embodied with said mandrels, said device being powered hydraulically from drilling liquid transmitted to said drill through said jar and automatically axially contracting the elements of said jar while said drill is being operated under a high liquid pressure to give said spline device maximum effectiveness in transmitting torque to said drill.

Claim 3

A combination as recited in claim 1, wherein said spline retraction device includes an annular hydraulic cylinder formed between said mandrels the two ends of which comprise cylinder heads formed by said outer mandrel and are in slideable sealed relation with said inner mandrel; an annular piston fixed on said inner mandrel and slideable in said cylinder between said cylinder heads, said piston making a sealing fit with said outer mandrel, and wherein aperture means are provided in said inner mandrel just below said piston to admit drilling liquid from said inner mandrel into said cylinder between said piston and said lower head to lift said piston, and wherein aperture means are provided in said outer mandrel just below said upper head to maintain ambient liquid pressure in said cylinder above said piston.

Claim 4

A combination as recited in claim 2 wherein said external mandrel connects upwardly to said drill string; said internal mandrel connects downwardly to said drill, and wherein said retraction device is located in the top end portion of the tool; said spline device is located in the bottom end portion of the tool, and said jarring device is located between the other two devices.

Claim 5

A combination as recited in claim 3 wherein said jarring device is of the hydraulic, sleeve valve tripping type, the parts of which including an operating lubricant occupying an annular lubricant chamber provided between a lower seal fixed on said external mandrel and slideably engaging said internal mandrel, and an upper seal slideably sealingly engaging both mandrels, an ambient pressure chamber being formed between said upper seal and said lower cylinder head, and wherein aperture means are provided in said external mandrel giving access of well liquid to said ambient pressure chamber.

Claim 6

A combination as recited in claim 1 wherein said spline device includes a split wear and retainer sleeve; and a spline device assembly collar screwing onto the lower end of said external mandrel to enclose and trap said retainer sleeve with said retainer sleeve in axially abutting relation with said male splines, to keep said spline device from coming apart should the internal mandrel part at a point above said male splines.

Claim 7

A combination as recited in claim 5 wherein said spline device includes: upper and lower annular packers at the upper and lower ends of said device to provide an annular lubricant chamber between said mandrels exclusively for confining said spline device in a lubricant; and means for trapping said lower annular packer within a lower portion of said assembly collar to make sealing engagement between said collar and said internal mandrel.

Claim 8

In a deep well tool, thhe combination of: internal and external tubular mandrels telescopically related; means for connecting the top end of one mandrel to a drill string and the bottom end of the other mandrel to a drill bit or the like; a spline device including: a male spline sub embodied with said internal mandrel and having an outer end portion thereof extending slideably outwardly from within the free end portion of said external mandrel; an inner end portion of said male spline sub slideably fitting within an adjacent portion of said external mandrel; male spline means provided on a middle portion of the external surface of said male spline sub; female spline means provided on said external mandrel and extending inwardly in splined relation with said male splIne means; and means limiting telescopic movement between said mandrels to maintain said male and female spline means in constantly meshed relation, a spline device assembly collar which screws onto said free end of said external mandrel, said collar having an annular internal recess; a split retaining sleeve fitting within said collar against the free end of said external mandrel and having an annular external flange which fits within said internal recess of said collar, said male spline sub outer end portion beyond said male spline means making a sliding fit with said split retaining sleeve, said spline device thus being held together by said collar and split sleeve, allowing said device to be recovered in the event of said inner mandrel parting inwardly from said male spline means.

Claim 9

In a deep well tool, thhe combination of: internal and external tubular mandrels telescopically related; means for connecting the top end of one mandrel to a drill string and the bottom end of the other mandrel to a drill bit or the like; a spline device including: a male spline sub embodied with said internal mandrel and having an outer end portion thereof extending slideably outwardly from within the free end portion of said external mandrel; an inner end portion of said male spline sub slideably fitting within an adjacent portion of said external mandrel; male spline means provided on a middle portion of the external surface of said male spline sub; female spline means provided on said external mandrel and extending inwardly in splined relation with said male splIne means; and means limiting telescopic movement between said mandrels to maintain said male and female spline means in constantly meshed relation, a spline device assembly collar which screws onto said free end of said external mandrel, said collar having an annular internal recess; a split retaining sleeve fitting within said collar against the free end of said external mandrel and having an annular external flange which fits within said internal recess of said collar, said male spline sub outer end portion beyond said male spline means making a sliding fit with said split retaining sleeve, said spline device thus being held together by said collar and split sleeve, allowing said device to be recovered in the event of said inner mandrel parting inwardly from said male spline means.