A torque limiting assembly is disclosed comprising: an input shaft; an output shaft; and spring having a first end coupled to the input shaft and a second end coupled with the output shaft. In a low torque mode, when the input shaft is rotated the spring is compressed by a low amount and transmits a force to drive rotation of the output shaft, whereas in a high torque mode the spring is compressed by a high amount such that the input shaft rotates relative to the output shaft. This relative rotation moves or urges an engagement member so as to either: disconnect the input shaft from the output shaft; or engage a housing to prevent or inhibit rotation of the input shaft relative to the housing.

A clutch includes balls, an axle, a socket and a cylinder. The axle includes a circular section formed with alternate cavities and ridges. The socket includes a circular bore for receiving the circular section of the axle and apertures for receiving the balls. The cylinder includes an annular recess made in an internal face. The socket is movable in the cylinder between two positions. When the socket is the first position, the internal face of the cylinder abuts the external portions of balls to engage the internal portions of the balls with the ridges to cause the axle to rotate the socket via the balls. When the socket is in the second position, the annular recess receives the external portions of the balls to allow disengagement of the internal portions of balls from the ridges to allow the axle to rotate relative to the socket.

A clutch includes balls, an axle, a socket and a cylinder. The axle includes a circular section formed with alternate cavities and ridges. The socket includes a circular bore for receiving the circular section of the axle and apertures for receiving the balls. The cylinder includes an annular recess made in an internal face. The socket is movable in the cylinder between two positions. When the socket is the first position, the internal face of the cylinder abuts the external portions of balls to engage the internal portions of the balls with the ridges to cause the axle to rotate the socket via the balls. When the socket is in the second position, the annular recess receives the external portions of the balls to allow disengagement of the internal portions of balls from the ridges to allow the axle to rotate relative to the socket.

There is disclosed a torque transfer apparatus for a mineral drilling tool used in a downhole assembly of a drill string. The drilling tool has a downhole drill bit and one or more uphole drill bits spaced apart from the downhole drill bit, with the torque transfer apparatus being located between them. The apparatus has an axial bore therethrough for fluid flow and comprises first and second members being rotatably joined to each other. The apparatus rotationally couples and transfers torque between the first and second members when a torque difference between torque on the downhole drill bit and torque on the uphole drill bit is below a threshold torque value. The apparatus disengages the rotational coupling while the torque difference exceeds the threshold torque value. The flow rate of drilling fluid flowing through the axial bore is altered when the apparatus engages and disengages the coupling.

There is disclosed a torque transfer apparatus for a mineral drilling tool used in a downhole assembly of a drill string. The drilling tool has a downhole drill bit and one or more uphole drill bits spaced apart from the downhole drill bit, with the torque transfer apparatus being located between them. The apparatus has an axial bore therethrough for fluid flow and comprises first and second members being rotatably joined to each other. The apparatus rotationally couples and transfers torque between the first and second members when a torque difference between torque on the downhole drill bit and torque on the uphole drill bit is below a threshold torque value. The apparatus disengages the rotational coupling while the torque difference exceeds the threshold torque value. The flow rate of drilling fluid flowing through the axial bore is altered when the apparatus engages and disengages the coupling.

One embodiment of the present invention provides an actuator comprising: a housing having a mounting space part formed therein; a motor part provided inside the housing and generating power; a reduction gear part of which a plurality of gears respectively having an internal gear and an external gear sequentially engage with each other so as to transmit the power generated in the motor part; and a rod part engaging with the gear disposed at the last position, and linearly moving according to the rotation of the gear, wherein one of the plurality of gears is formed such that the internal gear and the external gear can rotate together or rotate independently.

One embodiment of the present invention provides an actuator comprising: a housing having a mounting space part formed therein; a motor part provided inside the housing and generating power; a reduction gear part of which a plurality of gears respectively having an internal gear and an external gear sequentially engage with each other so as to transmit the power generated in the motor part; and a rod part engaging with the gear disposed at the last position, and linearly moving according to the rotation of the gear, wherein one of the plurality of gears is formed such that the internal gear and the external gear can rotate together or rotate independently.

A torque limiting assembly is disclosed comprising: an input shaft; an output shaft; and spring having a first end coupled to the input shaft and a second end coupled with the output shaft. In a low torque mode, when the input shaft is rotated the spring is compressed by a low amount and transmits a force to drive rotation of the output shaft, whereas in a high torque mode the spring is compressed by a high amount such that the input shaft rotates relative to the output shaft. This relative rotation moves or urges an engagement member so as to either: disconnect the input shaft from the output shaft; or engage a housing to prevent or inhibit rotation of the input shaft relative to the housing.

A torque limiting assembly is disclosed comprising: an input shaft; an output shaft; and spring having a first end coupled to the input shaft and a second end coupled with the output shaft. In a low torque mode, when the input shaft is rotated the spring is compressed by a low amount and transmits a force to drive rotation of the output shaft, whereas in a high torque mode the spring is compressed by a high amount such that the input shaft rotates relative to the output shaft. This relative rotation moves or urges an engagement member so as to either: disconnect the input shaft from the output shaft; or engage a housing to prevent or inhibit rotation of the input shaft relative to the housing.

A torque limiting device comprises rotationally mounted input and output shafts, an intermediate drive element rotationally coupled to the input shaft and a plurality of jammer elements mounted between the intermediate drive element and the output shaft. A spring mechanism is connected between the input shaft and the intermediate drive element for aligning the intermediate drive element and the input shaft in a driving configuration in which rotation of the input shaft at a torque below a predetermined threshold is transmitted to the output shaft via the jammer element, but in which torque above the predetermined threshold moves the input shaft rotationally relative to the intermediate drive element against the force of the spring mechanism so as to disengage that jammer elements from driving engagement with the output shaft.