Coupling a top drive to tools. A drive unit includes a drive stem having torque gear profile, threaded load coupling, torque sleeve movable between first position and second position, a sleeve gear profile engaging the torque gear profile when in second position; or spindle unit and annular motor coupled to the spindle unit; or drive stem having first friction surfaces; transmission unit having second friction surfaces parallel to first friction surfaces; and transmission selector movable to an on or an off position. A method may include rotating a drive stem of drive unit, threading coupling with a tool stem of tool adapter; moving a torque sleeve of drive unit to engage a torque gear profile of the drive stem and a stem gear profile of the tool stem; or rotating a spindle unit relative to drive stem to contact a counter nut of spindle unit with the tool stem.

A torque limiting coupling has a shaft, a shear plate fixedly connected to the shaft, and a coaxially disposed coupling ring. The coupling ring has a lateral surface in contact with the shaft and a double-walled section with an internal annular pressure fluid chamber. When the fluid chamber is filled with pressurized fluid, the radial thickness increases and increases the pressure and friction forces for a torque transfer between the coupling ring and the shaft. A shear tube closes the pressurized fluid chamber. A shear plate is configured to cut off a tip of the shear tube in order to open the pressure fluid chamber when the first shaft slips relative to the coupling ring. A central bolt affixes the shear plate to the shaft by pressing a conical bushing of the shear plate onto a conical connector of the shaft.

A wind turbine (101) comprising a torque transmitting coupling (1) between a first rotatable part (2, 3) and a second rotatable part (2, 3) of the wind turbine (101), e.g. in the form of a hub (2) and a shaft (3), is disclosed. The torque transmitting coupling (1) comprises a form- fitted coupling and a compression means (5, 8, 9, 12, 13). The form-fitted coupling defines a plurality of drive flanks formed on the first rotatable part (2, 3) and a plurality of driven flanks formed on the second rotatable part (2, 3). The compression means (5, 8, 9, 12, 13) is arranged on an internal or external perimeter of the form-fitted coupling, and the compression means (5, 8, 9, 12, 13) provides a frictional coupling between the first rotatable part (2, 3) and the second rotatable part (2, 3). The torque transmitting coupling (1) is capable of locking up to six degrees of freedom between the first rotatable part (2, 3) and the second rotatable part (2, 3), while allowing the first rotatable part (2, 3) and the second rotatable part (2, 3) to be easily dissembled.

A wind turbine (101) comprising a torque transmitting coupling (1) between a first rotatable part (2, 3) and a second rotatable part (2, 3) of the wind turbine (101), e.g. in the form of a hub (2) and a shaft (3), is disclosed. The torque transmitting coupling (1) comprises a form- fitted coupling and a compression means (5, 8, 9, 12, 13). The form-fitted coupling defines a plurality of drive flanks formed on the first rotatable part (2, 3) and a plurality of driven flanks formed on the second rotatable part (2, 3). The compression means (5, 8, 9, 12, 13) is arranged on an internal or external perimeter of the form-fitted coupling, and the compression means (5, 8, 9, 12, 13) provides a frictional coupling between the first rotatable part (2, 3) and the second rotatable part (2, 3). The torque transmitting coupling (1) is capable of locking up to six degrees of freedom between the first rotatable part (2, 3) and the second rotatable part (2, 3), while allowing the first rotatable part (2, 3) and the second rotatable part (2, 3) to be easily dissembled.

An axle assembly having a countershaft. The countershaft may be disposed in an axle housing. An axle shaft may be disposed in the countershaft. A first clutch may control rotation of the countershaft with respect to the axle shaft. A second clutch may control rotation of the countershaft with respect to the axle housing.

A composite shaft with an end fitting mounted on an interface region on at least one end of said shaft, and a preload structure arranged to provide a biasing force to bias the composite shaft against the end fitting; wherein the preload structure is in an interference fit with the composite shaft. The preload structure is applied to the composite shaft in a subsequent operation to the mounting of the end fitting to the shaft.

A composite shaft with an end fitting mounted on an interface region on at least one end of said shaft, and a preload structure arranged to provide a biasing force to bias the composite shaft against the end fitting; wherein the preload structure is in an interference fit with the composite shaft. The preload structure is applied to the composite shaft in a subsequent operation to the mounting of the end fitting to the shaft.

Coupling a top drive to tools. A drive unit includes a drive stem having torque gear profile, threaded load coupling, torque sleeve movable between first position and second position, a sleeve gear profile engaging the torque gear profile when in second position; or spindle unit and annular motor coupled to the spindle unit; or drive stem having first friction surfaces; transmission unit having second friction surfaces parallel to first friction surfaces; and transmission selector movable to an on or an off position. A method may include rotating a drive stem of drive unit, threading coupling with a tool stem of tool adapter; moving a torque sleeve of drive unit to engage a torque gear profile of the drive stem and a stem gear profile of the tool stem; or rotating a spindle unit relative to drive stem to contact a counter nut of spindle unit with the tool stem.

Coupling a top drive to tools. A drive unit includes a drive stem having torque gear profile, threaded load coupling, torque sleeve movable between first position and second position, a sleeve gear profile engaging the torque gear profile when in second position; or spindle unit and annular motor coupled to the spindle unit; or drive stem having first friction surfaces; transmission unit having second friction surfaces parallel to first friction surfaces; and transmission selector movable to an on or an off position. A method may include rotating a drive stem of drive unit, threading coupling with a tool stem of tool adapter; moving a torque sleeve of drive unit to engage a torque gear profile of the drive stem and a stem gear profile of the tool stem; or rotating a spindle unit relative to drive stem to contact a counter nut of spindle unit with the tool stem.

A drive unit includes a drive stem having first friction surfaces and a load coupling, wherein the load coupling is a threaded coupling. The drive unit also includes a transmission unit having second friction surfaces parallel to the first friction surfaces; and shoulders proximate a bottom of the transmission unit. The drive unit further includes a transmission selector movable to an on position or an off position, wherein the drive stem moves synchronously with the transmission unit when the transmission selector is in the on position.