Sandvik Ab

Sandvik Intellectual Property Ab

Santrade, Ltd

Sandvik Intellectual Property Aktiebolag

Kenneth L Larsson

Ralf Lehto

Isak Kakai

Bert G Levefelt

Magnus Örtlund

Rainer Beccu

Bengt &angst;sberg

Sven P Liljebrand

Ann-Cathrin Hedlund

Bertil Ederyd

G&ouml;sta Reuter

Rolf Mor&eacute;n

Rolf Moren

A cutting tool, and a loose top therefore, includes two parts detachably connected to each other via a threaded joint in which co-operating male and female threads are included in the form of helicoidal ridges. The profile shape of each helicoidal ridge is defined by a top and two flanks, which delimit a helicoidal groove having a bottom. The first flank is inclined in relation to a center axis of the tool at a first angle that is smaller than a second angle of the second flank in relation to the center axis. Accordingly, the thread ridge is reinforced in comparison with thread ridges having a symmetrical profile shape, whereby larger tensile forces than compressive forces can be applied to the threaded joint while avoiding damage to the thread ridges.

Tool for chip removing machining as well as a part and threaded joint therefor

A drill rod for percussive rock drilling includes a first rod part and an additional second rod part. The first rod part includes first and second ends, an inner duct, and an external thread disposed adjacent the first end, wherein the external thread is at least partly hardened by heat treatment. The additional rod part includes first and second ends, an inner duct, and an internally thread disposed adjacent the first end thereof, wherein the internal thread is at least partly hardened by heat treatment. The first ends of the respective first and second rod parts are threadedly secured to one another, and the second ends of the respective first and second rod parts are welded together to define a weld zone having a substantially martensitic structure. If there is further provided an intermediate hollow rod part, then the second ends of the respective first and second rod parts would be welded to respective ends of the intermediate hollow part to define weld zones having a substantially martensitic structure.

Drill rod and method of manufacture thereof

Portion of a drill bit

Two components used in a percussive drill string include a spigot and a sleeve, respectively. The spigot includes a male thread connected to a female thread of the sleeve to form a thread joint. The male and female threads are dimensioned such that axially inner and outer end areas of the female thread are in non-engagement with the male thread when the thread joint is in a tightened state. The spigot includes axially inner and outer conical guiding surfaces facing toward respective axially outer and inner conical guiding surfaces, respectively. Each conical guiding surface forms an angle with a centerline of the sleeve, the angle lying in the range 1 to 20 degrees, to prevent the spigot and the sleeve from being welded together by frictional heat during a drilling operation.

Thread joint and threaded components for percussive drilling components

A guide tube for use in a rock drill string includes a main portion, a sleeve disposed at a first end of the main portion, and a male thread portion disposed at a second end of the main portion. The sleeve forms a recess having a female thread. A flush channel extends through the guide tube. The main portion includes a section of reduced cross-section disposed adjacent the sleeve for defining a generally radially extending shoulder between the waist and the sleeve. The shoulder serves to support the guide tube on a rig as percussion is applied to the guide tube for loosening a threaded joint between the guide tube and another member.

Guide tube of a drill string configured to facilitate unscrewing thereof from a member of the drill string

A percussive drill for extension drilling includes a drill bit, a tube having a male screw thread attached to a female screw thread of the drill bit, and a rod having a male screw thread attached to a female screw thread of the tube. Central passages of the rod and tube are aligned with one another to conduct flushing fluid to the drill bit. The drill bit drills a hole whose diameter is from 60-170 mm and at least twice the outer diameter of the rod. A total area of a cross-sectional surface of the tube is within 100-125% of a total area of a cross sectional surface of the rod.

Percussive drilling apparatus

A rock drill bit for percussive drilling, especially top hammer drilling, includes a bit head provided with front rock crushing buttons and a skirt. The bit head is provided with a number of grooves formed in the outside of the skirt and extending in the axial direction of the drill bit. Protruding lands are defined between the grooves, which likewise extend in the axial direction. Axially rearward ends of at least some of the lands are formed with retrac teeth. Each retrac tooth has a cutting edge extending along an outer circumference of the skirt.

Rock drill bit having retrac teeth and method for its manufacturing

Rock drilling tool, drill bit and a method of transferring percussive

The invention relates to a tool for breaking or excavating of hard material, such as asphalt. The tool comprises a cutting insert (11) secured to a tool body (10). For purposes maintaining the required cutting force low while ensuring that the risk is low that the cutting insert (11) will get loose the cutting insert (11) is provided with a concave portion (17.sup.1) between the tip portion (12) of the cutting insert and a rear shoulder (13) thereon.

Excavating tool cutting insert

A drill string element for use in top hammer percussive drilling comprises first and second tubes coupled together by a cylindrical thread, and at least one impact-transmitting ord slidably disposed in the tubes. The rod(s) includes abutments which engage restrictions formed at remote ends of the tubes whereby the rod(s) can be removed only by unscrewing the tubes from one another. Remote ends of the tubes define male and female conical threads which enable the element to be connected to similar elements in the forming of a drill string. The conical threads are easier to unscrew than the cylindrical threads to avoid an accidental separation of the tubes of each element when that element is being unscrewed from another element.

Drill string element

The invention relates to a tool for breaking or excavating hard material, such as asphalt. The tool comprises a cutting insert (11) secured to a tool body (10). For purposes of maintaining the required cutting force low while ensuring that the risk is low that the cutting insert (11) will get loose the cutting insert (11) is provided with a concave portion (17.sup.1) between the tip portion (12) of the cutting insert and a rear shoulder (13) thereon.

A threaded coupling for a high frequency percussion drill assembly comprises a rod and a sleeve having external and internal threads, respectively. The threads are of the asymmetrical type and make contact along opposing shoulder portions disposed on only one side of each crown portion. The threads have a maximum diameter from 30 to 40 mm, a pitch of 7 to 11 mm, and a height from 1.2 to 1.6 mm. The parts of the root and crown portions located immediate adjacent the contacting shoulder portions have radii from 3 to 5 mm.

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Sandviken, Sweden

Kenneth L Larsson