This invention builds up on technical features and on the industry experience with the use of Merlin™ family connectors. In addition to friction, structural means utilized to transfer high torsional loads include interlocked thread systems and may also include: dog-clutch teeth, shear pins, keys and splines, all used in isolation or in arbitrary combinations. Static and fatigue bending load capacities of the connectors remain high, while the axial load capacities may or may not be high, depending on the design requirements. Connectors according to this invention can be built as new, carefully optimized designs. In some cases upgrading existing Merlin™ family connector designs to increase they torque transfer capacities may be also feasible.

Threaded tubular connection comprising a tubular female end extending from a main body of a first tubular member, and a tubular male end extending from a main body of a second tubular member, such that the tubular female end comprises a machined outer cylindrical surface close to the female free end having a first outer diameter and a second machined outer cylindrical surface above a threaded portion of the female end, a second outer diameter of the second outer cylindrical surface being bigger than the first outer diameter.

A sealing system connecting first and second tubular members includes a first curvilinear sealing surface on the first tubular member and a second curvilinear sealing surface on the second tubular member. Both the first and second curvilinear sealing surfaces are disposed between two sets of threading on the respective first and second tubular members. When the first and second tubular members are in a connected configuration, the first and second curvilinear sealing surfaces contact and interfere to form an annular curvilinear center seal. A relief pocket may be disposed adjacent to the first and/or second curvilinear sealing surfaces to contain excess lubricant between the first and second tubular members.

An axial linkage acting between the main body and the gripping assembly of a tool for gripping tubular workpieces includes a drive cam body that coaxially engages an intermediate cam body via a drive thread, with the intermediate cam body coaxially engaging a driven cam body via a driven thread, and with the drive thread and the driven thread having opposite orientations. The linkage includes a latch mechanism for preventing relative axial displacement of the drive cam body and the driven cam body. In operation while unlatched, the linkage converts bi-directional relative rotation into relative axial movement of the drive cam body and the driven cam body, thus increasing or decreasing the overall length of the linkage according to the rotational direction. The linkage can be re-latched using any of multiple operational sequences.

This invention builds up on technical features and on the industry experience with the use of Merlin™ family connectors. In addition to friction, structural means utilized to transfer high torsional loads include interlocked thread systems and may also include: dog-clutch teeth, shear pins, keys and splines, all used in isolation or in arbitrary combinations. Static and fatigue bending load capacities of the connectors remain high, while the axial load capacities may or may not be high, depending on the design requirements. Connectors according to this invention can be built as new, carefully optimized designs. In some cases upgrading existing Merlin™ family connector designs to increase they torque transfer capacities may be also feasible.

This invention builds up on technical features and on the industry experience with the use of Merlin™ family connectors. In addition to friction, structural means utilized to transfer high torsional loads include keys and may also include: interlocked thread systems, shear pins, dog-clutch teeth and splines, all used in isolation or in arbitrary combinations. Static and fatigue bending load capacities of the connectors remain high, while the axial load capacities may or may not be high, depending on the design requirements. Connectors according to this invention can be built as new, carefully optimized designs. In some cases upgrading existing Merlin™ family connector designs to increase they torque transfer capacities may be also feasible.

This invention builds up on technical features and on the industry experience with the use of MerlinTM family connectors. In addition to friction, structural means utilized to transfer high torsional loads include shear pins and may also include: interlocked thread systems, dog-clutch teeth, keys and splines, all used in isolation or in arbitrary combinations. Static and fatigue bending load capacities of the connectors remain high, while the axial load capacities may or may not be high, depending on the design requirements. Connectors according to this invention can be built as new, carefully optimized designs. In some cases upgrading existing Merlin™ family connector designs to increase they torque transfer capacities may be also feasible.

This invention builds up on technical features and on the industry experience with the use of Merlin™ family connectors. In addition to friction, structural means utilized in order to transfer high torsional loads include: dog-clutch teeth, shear pins, keys, splines and interlocked thread systems, all used in isolation or in arbitrary combinations. Static and fatigue bending load capacities of the connectors remain high, while the axial load capacities may or may not be high, depending on the design requirements. Connectors according to this invention can be built as new, carefully optimized designs. In some cases upgrading existing Merlin™ family connector designs to increase they torque transfer capacities may be also feasible.

Threaded tubular connection for the casing of hydrocarbon wells obtained by makeup of a male tool joint with a female tool joint, the connection includes in order from a free edge of the male tool joint: an inner metal-metal seal, a first threaded portion, an intermediate abutment, an intermediate metal-metal seal and a second threaded portion, the free edge being at a non-zero axial distance from the female tool joint, the threaded portions each comprising a helix equipped with a load flank, a thread crest, a stabbing flank, a thread root, such that a pitch of the load flank and a pitch of the stabbing flank of the first threaded portion, and respectively a pitch of the load flank and a pitch of the stabbing flank of the second threaded portion fulfil the following condition: SFLb1=LFLb1=SFLb2=LFLb2=SFLp1=SLFLp2=LFLp2.

Threaded tubular connection for the casing of hydrocarbon wells obtained by makeup of a male tool joint with a female tool joint, the connection comprising a threaded portion (16a, 18a), such that the male and respectively female threaded portions each comprise a helix provided with a load flank, a thread crest, a stabbing flank, a thread root, such that a pitch of the load flank (LFLp, LFLb) and a pitch of the stabbing flank (SFLp, SFLb) fulfils the following condition: [Math 22] SFL.sub.b=LFL.sub.b=SFL.sub.p=LFL.sub.p=k, A tooth width (Wtp) of the male helix and a tooth width of the female helix (Wtb) are such that [Math 23] or [Math 24] and [Math 25] Wtp+Wtb<k