Well drilling tool

A well drilling tool, comprising an elongated body connectible as part of a drill string, said body having relatively rotatable tubular members forming a passageway through which drilling fluid may be circulated and an annular space between the members, bearings within the annular space supporting one member from the other, means sealing between the members within the space to form a lubricant chamber for the bearings, means within the body providing a reservoir for supplying additional lubricant to the chamber, and means responsive to a predetermined decrease in the volume of lubricant within the reservoir for restricting the flow of drilling fluid through the passageway.

A well drilling tool, comprising an elongated body connectible as part of a drill string, said body having relatively rotatable tubular members forming a passageway through which drilling fluid may be circulated and an annular space between the members, bearings within the annular space supporting one member from the other, means sealing between the members within the space to form a lubricant chamber for the bearings, means within the body providing a reservoir from which additional lubricant may be supplied to the chamber, a part releasably supported in the passageway of the body, means for releasing said part in response to a predetermined decrease in the volume of lubricant within the reservoir, and means within the passageway for receiving said part, when so released, in order to restrict the flow of drilling fluid through the passageway.

A well drilling tool, comprising an elongated body connectible as part of a drill string, said body having relatively rotatable tubular members forming a passageway through which drilling fluid may be circulated and an annular space between the members, bearings within the annular space supporting one member from the other, means sealing between the members within the space to form a lubricant chamber for the bearings, means within the body providing a reservoir for supplying additional lubricant to the chamber, a first part movable longitudinally within the passageway means releasably supporting the first part within the bore, a second part movable longitudinally within the reservoir in response to a decrease in the volume of the lubricant, means for releasing the first part when the second part has moved to a predetermined longitudinal position within the reservoir, and means within the passageway for receiving said first part, when so released, in order to restrict the flow of drilling fluid through the passageway.

A well drilling tool, comprising an elongate body connectible as part of a drill string, said body having relatively rotatable tubular members forming a passageway through which drilling fluid may be circulated and an annular space between the members, bearings within the annular space supporting one member from the other, means sealing between said members with the space to form a lubricant chamber for the bearings, means within the body providing a reservoir for supplying additional lubricant to the chamber, a first part movable longitudinally within the passageway, means releasably supporting the first part within the passageway, a piston sealably slidable longitudinally the reservoir, one side of the piston being responsive to the pressure of the drilling fluid so as to force lubricant into said chamber as the piston is moved in one longitudinal direction, means for releasing said part in the passageway when the piston has moved to a predetermined longitudinal position within the reservoir, and means within the passageway for receiving said part, when so released, in order to restrict the flow of drilling fluid through the passageway.

A well drilling tool, comprising an elongated body connectible as part of a drill string, said body having relatively rotatable tubular members forming a passageway through which drilling fluid may be circulated and an annular space between the members, bearings within the annular space supporting one member from the other, means sealing between the members within the space to form a lubricant chamber for the bearings, and means for indicating to an operator at surface level that the volume of said lubricant has decreased a predetermined amount.

A well drilling tool, comprising an elongated body connectible as part of a drill string, said body having relatively rotatable tubular members forming a passageway through which drilling fluid may be circulated and an annular space between the members, bearings within the annular space supporting one member from the other, means sealing between the members within the space to form a lubricant chamber for the bearings, and means responsive to a predetermined decrease in the volume of said lubricant for restricting the flow of drilling fluid through the passageway.

A well drilling tool, comprising an elongated body connectible as part of a drill string, said body having relatively rotatable tubular members forming a passageway through which drilling fluid may be circulated and an annular space between the members, bearings within the annular space supporting one member from the other, means sealing between the members within the space to form a lubricant chamber for the bearings, a part movable within the body from a first position to a second position in which it restricts flow through the passageway to a greater extent than it does in its first position, means for retaining said part in its first position, and means for releasing said retaining means so as to permit said part to move to said second position when the volume of said lubricant has decreased a predetermined amount.