Rotary jar

Claim 2

A rotary jar for an oil well tool which comprises a tubular housing having one end attachable to a well tool, a mandrel extending into said housing and having an end portion externally of said housing attachable to a drill string, said mandrel having a splined connection with said housing permitting non-rotative reciprocating movement of said mandrel relative to said housing, said housing having an internal annular shoulder constituting an anvil, said mandrel having an annular shoulder confronting said internal annular shoulder and constituting a knocker, means forming a substantially confined annular chamber between said mandrel and housing for reception of a working fluid, a piston in said chamber slidingly mounted on said mandrel, said mandrel having stop means limiting sliding movement of said piston on said mandrel and operable to apply reciprocating movement to said piston with said mandrel, said piston having a restricted fluid passage extending therethrough, control valve means in said passage and sleeve means in said housing and engagable by said piston to provide a fluid passage around said piston.

Claim 3

A rotary jar for an oil well tool which comprises a tubular housing having one end attachable to a well tool, a mandrel extending into said housing and having an end portion externally of said housing attachable to a drill string, said mandrel having a splined connection with said housing permitting non-rotative reciprocating movement of said mandrel relative to said housing, said housing having an internal annular shoulder constituting an anvil, said mandrel having an annular shoulder confronting said internal annular shoulder and constituting a knocker, means forming a substantially confined annular chamber between said mandrel and housing for reception of a working fluid, a piston in said chamber slidingly mounted on said mandrel, said mandrel having stop means limiting sliding movement of said piston on said mandrel and operable to apply reciprocating movement to said piston with said mandrel, said piston having a restricted fluid passage extending therethrough, control valve means in said passage and sleeve means in said housing and engagable by said piston to provide a fluid passage around said piston.

Claim 4

A rotary jar for an oil well tool which comprises a tubular housing having one end attachable to a well tool, a mandrel extending into said housing and having an end portion externally of said housing attachable to a drill string, said mandrel having a splined connection with said housing permitting non-rotative reciprocating movement of said mandrel relative to said housing, said housing having an internal annular shoulder constituting an anvil, said mandrel having an annular shoulder confronting said internal annular shoulder and constituting a knocker, means forming a substantially confined annular chamber between said mandrel and housing for reception of a working fluid, a piston in said chamber slidingly mounted on said mandrel, said mandrel having stop means limiting sliding movement of said piston on said mandrel and operable to apply reciprocating movement to said piston with said mandrel, said piston having a restricted fluid passage extending therethrough, control valve means in said passage and sleeve means in said housing and engagable by said piston to provide a fluid passage around said piston.

Claim 5

A rotary jar according to claim 1 wherein said control valve is a porous metallic cartridge.

Claim 6

A rotary jar according to claim 1 wherein said piston includes an annular ring slidably mounted on said mandrel and within said chamber, and wherein said stop means includes an annular rim on said mandrel located between said ring and said sealing means adjacent said knocker and an annular piston seat on said mandrel and within said chamber.

Claim 7

A rotary jar according to claim 3 wherein said control valve means includes an annular resilient piston cup within said chamber, having an inner diameter greater than the outside diameter of said mandrel but less than that of said rim and located between said piston and said rim, a small diameter bore through said cup in a direction longitudinal of said mandrel and between said mandrel and housing, a counterbore in said piston and having a diameter greater than the diameter of said bore to receive said porous cartridge, a second small diameter bore in said piston axially aligned with said bore and communicating said counter bore with said chamber, and a third small diameter bore through said piston seat and axially aligned with said second bore.

Claim 8

A rotary jar according to claim 1 wherein said knocker is a collar extending radially outwards from said mandrel into proximity with said housing and said anvil is a collar extending radially inwards from said housing into proximity with said mandrel.

Claim 9

A rotary jar according to claim 4 wherein said splined connection comprises radially extending longitudinal splines on said mandrel and extending from said knocker away from said chamber, and longitudinal grooves in said collar for cooperation with said splines to prevent turning of said housing relative to said mandrel.

Claim 10

A rotary jar according to claim 5 wherein said cartridge is porous brass or bronze.

Claim 11

A rotary jar for an oil well tool including an inner mandrel adapted for attachment to a drill string, an outer housing mutually extensible with said mandrel and adapted for attachment to a well tool, spline means between said mandrel and housing permitting non-rotative mutual extension of said mandrel and housing, annular knocker means on said mandrel, annular anvil means in said housing for coaction with said knocker, annular seal means in said housing, said seals being in sealing contact with said mandrel, being spaced apart longitudinally in said housing in one direction from said knocker and anvil, and defining a chamber therebetween in an annular cavity between said mandrel and housing, said chamber adapted to receive a working fluid which exhibits only small viscosity changes with large temperature changes, piston means slidable on said mandrel and located in said chamber, means forming a valve combination within said chamber whereby said valve combination includes a porous cartridge adapted to permit minute quantities of a working fluid therethrough during mutual extension of said mandrel and housing and means forming a by-pass to said porous cartridge adapted to permit large quantities of a working fluid to pass therethrough during mutual contraction of said mandrel and housing, and means forming a recess in said housing within said chamber adjacent the seal nearest said knocker and anvil for receiving annular sleeve means such that when said valve combination and piston are moved adjacent said sleeve during mutual extension of said mandrel and housing, the sleeve will move with said valve combination and piston to permit rapid flow of a working fluid around said valve combination and piston effectively bypassing said porous cartridge to permit said knocker and anvil to come into jarring contact.

Claim 12

A rotary jar for an oil well tool including an inner mandrel adapted for attachment to a drill string, an outer housing mutually extensible with said mandrel and adapted for attachment to a well tool, spline means between said mandrel and housing permitting non-rotative mutual extension of said mandrel and housing, annular knocker means on said mandrel, annular anvil means in said housing for coaction with said knocker, annular seal means in said housing, said seals being in sealing contact with said mandrel, being spaced apart longitudinally in said housing in one direction from said knocker and anvil, and defining a chamber therebetween in an annular cavity between said mandrel and housing, said chamber adapted to receive a working fluid which exhibits only small viscosity changes with large temperature changes, piston means slidable on said mandrel and located in said chamber, means forming a valve combination within said chamber whereby said valve combination includes a porous cartridge adapted to permit minute quantities of a working fluid therethrough during mutual extension of said mandrel and housing and means forming a by-pass to said porous cartridge adapted to permit large quantities of a working fluid to pass therethrough during mutual contraction of said mandrel and housing, and means forming a recess in said housing within said chamber adjacent the seal nearest said knocker and anvil for receiving annular sleeve means such that when said valve combination and piston are moved adjacent said sleeve during mutual extension of said mandrel and housing, the sleeve will move with said valve combination and piston to permit rapid flow of a working fluid around said valve combination and piston effectively bypassing said porous cartridge to permit said knocker and anvil to come into jarring contact.

Claim 13

A rotary jar according to claim 3 wherein said sealing means are contained in radially inwardly extending portions of said housing at each end of the chamber so defined and are comprised of packing glands held in place by gland nuts, each gland nut being annular in shape and having an external thread for coaction with an internal thread in said housing adjacent said packing gland.