A bottom-hole feeding mechanism comprising: a cylinder (1), a screw spindle (2) engaging with the cylinder (1) by means of a non-stopping splined screw pair (3), a first piston (6) received within the cylinder (1) and coupled with the screw spindle (2) and a hollow rod (8), an axial spindle (4) arranged along the cylinder (1) axis and engaging the cylinder (1) by means of an axial splined pair (5), a second piston (7) rigidly coupled with the axial spindle (4) and engaging the inner surface of the cylinder (1) and the outer surface of the hollow rod (8), wherein the hollow rod (8), the first piston (6), the second piston (7) and the cylinder (1) form a closed chamber (9) comprising a throttle (10), hydraulic channels (11) on the body of a valve (21), and a float (12).

A sound absorber mountable between a drilling apparatus and a drill bit. The sound absorber defines an absorber axis therealong. The sound absorber includes a sleeve defining a chamber extending axially therealong, the chamber defining axially opposed chamber proximal and distal ends, the chamber being delimited by a chamber peripheral wall extending between the chamber proximal and distal ends and a chamber distal end wall provided at the chamber distal end, the sleeve defining a sleeve aperture leading to the chamber at the chamber proximal end. A piston is mounted to the sleeve so that at least part of the piston is in the chamber, the piston being reciprocatingly movable substantially axially along the sleeve, the piston defining axially opposed piston proximal and distal ends An absorbing system includes a first resilient element provided in the chamber between the piston distal end and the chamber distal end.

An assembly for inclusion between a drill bit and a drill string, the assembly having an overrunning clutch mechanism that disengages the drill bit from the drill string during the slip portion of a stick-slip cycle to allow the drill bit to freely rotate faster than the drill string. The assembly further includes a rotational vibration dampener operatively connected between the overrunning clutch and the drill bit. The vibration dampener may include a fluid chamber with viscous fluid or restrictions to fluid flow to effect dampening. During normal operation, the one-way overrunning clutch remains engaged to transfer torque between the drill string and bit, while the torsional damper is in its maximum displaced position to transfer the load. During slip, the drill bit is disengaged until its speed is lower than the drill string speed. Torsional vibration dampener dampens sudden impulse force of the overrunning clutch re-engaging.

A quick release down-the-hole (DTH) hammer drill bit assembly includes a drill bit releaseably retained at a drive transmission component (drive sub) via a retaining sleeve and respective retaining formations to axially couple and lock the drill bit at the assembly. In particular, the drill bit is retained exclusively at the assembly via retaining formations at the drive sub, the sleeve and the drill bit, without a requirement for additional retaining rings that would otherwise axially lock the drill bit at the drive sub.

The present invention relates to a drill bit assembly for fluid-operated percussion drill tools. The drill bit assembly comprises a percussion bit having a head portion formed with an axially extending shank, a first plurality of axially extending splines on the shank slideably engageable with a first plurality of complementary splines formed internally of a drive chuck whereby rotational drive from the chuck may be transmitted to the shank. The assembly also comprises engagement means on the chuck adapted for connecting the chuck to a drive means of the fluid-operated percussion drill tool. During drilling, the bit and the chuck are held in a first relative orientation in which the bit is retained in the chuck, and the bit is moveable axially relative to the chuck to a bit removal position, in which the bit is rotatable relative to the chuck to a second relative orientation in which the bit is removable from the chuck. The bit is moveable to the bit removal position while the chuck is fully engaged with the drive means.

A method for assembling a down-the-hole drilling apparatus including a drilling device including a casing and a drilling unit arranged during drilling in connection with the casing. The drilling unit includes a drilling head including a drilling arrangement including a first drilling member for drilling a center hole and a second drilling member for reaming the center hole. The drilling members are mutually power transmittingly coupled during drilling to cooperate for rotational, feeding and/or hammering, and removably coupled to enable removal of the first drilling member from a hole. The casing is arranged to be pulled into the hole through a shoulder arranged at an end of the casing. At an opposite end of the drilling arrangement with respect to a drilling surface, is arranged a skirt including a radial internal shoulder for pulling the casing into the hole by cooperation of the internal shoulder and an external shoulder at the end of the casing.

A petroleum drill-string shock absorber includes a drill collar nipple, a driving unit, an outer shell, a helical guideway, a drill bit base, a woven metal ring and a vibration-absorbing composite beam, the vibration-absorbing composite beam consists of a sheet metal and a flexible material gasket bonded by an adhesive; the drill collar nipple is connected with the helical guideway; the helical guideway is connected with the drill bit base; the driving unit rotates on the helical guideway; the outer shell is connected with the drill bit base; a metal seal ring is configured to seal a space formed between the outer shell and the drill collar nipple, a sealed space is formed among the drill collar nipple, the outer shell and the drill bit base; the woven metal ring is placed between the helical guideway and the drill bit base configured to absorb an axial impact vibration.

An apparatus and method for alleviating spiraling in boreholes is disclosed. The apparatus includes a sub, which adjusts the length of the bottom-hole assembly in response to tension/compression, flexural bending and/or torque measurements made above and below the reamer so that the drill bit and the reamer cut at the same depth rate. The sub is connected between the drill bit and the reamer. The apparatus further includes measurement devices disposed on the bottom-hole assembly above and below the reamer, which are capable of measuring the tension/compression, flexural bending and torque in the bottom-hole assembly. The method includes use of a data processor, which determines which operational output signals to supply to the sub in order to adjust its length and thereby accomplish the desired drilling rates.

An oscillation reduction tool configured to prevent or reduce high frequency torsional oscillation by torsionally decoupling a rotary steerable system from a bottom hole assembly, which includes a drilling motor. The tool may convert high frequency torsional oscillation into an internal axial movement without axial displacement of the tool's outer housing. The oscillation reduction tool may flatten an amplitude of high frequency torsional oscillation spikes throughout a spring arrangement. The mechanical energy associated with the internal axial movement is reduced through an internal shock absorbing mechanism, such as fluid movement through a nozzle or annular space. The oscillation reduction tool functions to reduce high frequency torsional oscillation independent of the weight on the bit of the drill string.

A sub-assembly, rock drilling rig and method of absorbing vibrations in rotary and DTH drilling. The sub-assembly is for transmitting torque and axial forces between a rotating head and a drilling tool. There is an axial floating arrangement for providing an allowed limited axial relative movement between coupling elements of the sub-assembly. The arrangement comprises several axial drive pins for transmitting the torque. First ends of the drive pins are mounted immovably and second ends are mounted with clearances, whereby the drive pins can bend under torsional shocks. Thus, the drive pins serve as torsional dampening elements.