Abstract: The invention relates to a drill drive for a drilling rig with a motor, by which a drive shaft is rotationally driven which is supported in a rotatable manner in a housing with a bearing arrangement having at least a radial bearing, a first axial bearing and a second axial bearing, wherein on the first axial bearing a first force measuring device is arranged for determining a first axial force on the first axial bearing and on the second axial bearing a second force measuring device is arranged for determining a second axial force on the second axial bearing. Furthermore, the invention relates to a drilling rig, in particular for oil or gas drilling, with a drill mast, along which a drill string with a drilling tool is arranged, wherein on the drill mast a drill drive according to the invention is supported in a displaceable manner for rotationally driving the drill string.

Abstract: There is provided a system and method for coupling with a shaft. In particular, there is provided a friction shaft coupler that includes a center plate and a plurality of outer plates, wherein the outer plates are configured to abut the center plate. The center plate and the plurality of outer plates each include a shaft bore configured to receive a shaft and a plurality of stub bores. The friction shaft coupler also includes a plurality of stubs, wherein each stub is configured to fit inside one of the plurality of stub bores, the plurality of stubs comprising a plurality of apertures that are perpendicular to a longitudinal axis of the stubs. Additionally, the friction shaft coupler includes a plurality of set screws configured to fit inside the apertures of the stubs, wherein the set screws are accessible for adjustment via access holes in the plurality of outer plates.

Abstract: In accordance with the present invention, a chain driven reciprocating hammer is disclosed. The chain driven reciprocating hammer includes a chain system for lifting a ram to a drop point. The chain system includes a plurality of sprockets and a chain with at least one mesh link to mesh with the ram. Additionally, the chain driven reciprocating hammer includes an adjustable tandem release sprocket mechanism. Also, the chain driven reciprocating hammer includes a center and clamping mechanism configured to secure a work input.

Abstract: An apparatus for automatically calculating the fall height of the ram of a pile driver is disclosed. The apparatus includes a device for converting the sound created by each blow of the pile driver ram into an electrical signal, a first circuit for converting signal into a pulse and a second circuit for converting the time elapsed between the pulses for consecutive blows into a digital output representing the fall height of the ram for the blow corresponding to the latter pulse. The digital electronic circuit may also include circuitry for counting the number of blows in a sequence of blows and circuitry for determining the average fall height for the blows occurring during the sequence.

Abstract: An apparatus for automatically calculating the fall height of the ram of a pile driver is disclosed. The apparatus includes a device for converting the sound created by each blow of the pile driver ram into an electrical signal, a first circuit for converting signal into a pulse and a second circuit for converting the time elapsed between the pulses for consecutive blows into a digital output representing the fall height of the ram for the blow corresponding to the latter pulse. The digital electronic circuit may also include circuitry for counting the number of blows in a sequence of blows and circuitry for determining the average fall height for the blows occurring during the sequence.