Sandvik Ab

Sandvik Intellectual Property Ab

Urban Olsson

Per-Olof Liljebrand

Rainer Beccu

Jan-Erik Sundstrom

Monica Olsson, Legal Representative

Rune Sand&eacute;n

A thread joint for transmitting percussive forces includes a male thread on a male member and a female thread on a female member. The male member includes a first portion including an outer surface having a maximum first outer cross section, a second portion having a second maximum outer dimension, and a third portion having the male thread formed thereon. The second portion is disposed axially between the first and third portions. The male thread includes a thread start and a thread end. The third portion terminates in an axially facing first end surface. The female member has a recess in which the female thread is formed, the female thread having a mouth defined by a ring-shaped second end surface. The recess includes a cylindrical inner surface disposed between the second end surface and the female thread. The inner surface faces the cylindrical center portion of the male member. The inner surface has a diameter at least as large as the second maximum outer cross-sectional dimension, and smaller than the first maximum cross section. A first imaginary cylinder constituting an axial extension of the inner surface intersects the first portion of the male member, and a second imaginary cylinder constituting an axial extension of an outermost surface of the female member extends outside of the first portion of the male member.

Thread joint

A rock-crushing rotary drill bit includes a body having a rock-crushing roller rotatably mounted thereon by bearings. The body includes a first flushing channel for conducting flushing fluid to flush the bearings, and a second flushing channel for discharging flushing medium outside of the bit body to flush away cuttings. The second flushing channel terminates in a discharge recess which defines a linear center axis. A nozzle is disposed at a downstream end of the discharge recess, and a valve element is disposed at an upstream end of the discharge recess. The valve element is spring-biased for closing the discharge recess, the valve element being openable against the spring bias in response to a sufficient pressure build-up of flushing medium within the second flushing channel. The valve element includes a guide structure for guiding the valve element for linear movement along the center axis of the discharge recess.

Rock drill bit and a check valve therefor

A thread joint for percussive drilling equipment includes first and second percussive drill string components, the first component including a spigot. An external thread is formed on the spigot, and an internal thread is formed on the second component. Each of the internal and external threads includes an end section gradually transforming into a full thread section. The end section includes a pair of flanks, and the full thread section also includes a pair of flanks. Both flanks of the end section have a different profile than the corresponding flanks of the full thread section.

Thread joint percussive drilling equipment

Method, drilling tool and rock drill bit for transferring impact energy

Growing community of inventors

Forsbacka, Sweden

Urban Olsson