Sandvik Mining and Construction Tools Ab

Sandvik Intellectual Property Ab

Anders Nordberg

Tomas Sh Jansson

Rasmus Hemph

Andreas Norman

Conny Kraft

Tomas Jansson

A shank adapter, forming part of a drilling assembly, has a main body extending axially between a first end and a second end, an externally threaded male spigot portion provided at the second end, and a non-threaded shank positioned axially intermediate the main body and the threaded section. A radially projecting shoulder is positioned axially between the main body and the male spigot portion. The shank has a transition section positioned adjacent to the shoulder at the second end having an outside diameter that increases in a direction from the spigot portion to the shoulder. A cross-sectional shape profile of the outer surface of the transition section has a segment of an ellipse having a semi-major axis (a), a semi-minor axis (b) and an exponential factor (n) according to the equation: A ratio of the semi-major to semi-minor axes (a:b) is within the range 2b<a<8b.

Elliptical design for shank adapters

A drill string rod is arranged to form part of an assembly of connected drill string rods. The drill string rod includes an elongate central rod portion extending axially between a male and female end. The central rod portion is a hollow-cylindrical defined by an inner first diameter (d) and an outer second diameter (D). The male end includes a spigot having a base projecting axially from a shoulder that axially separates the spigot and the central rod portion. The female end includes a sleeve portion configured to fit to the spigot. The base has an outer thread and the sleeve portion has an inner thread, the inner thread corresponding to the outer thread such that the inner thread of the sleeve portion is attachable to the outer thread of the base of the spigot of a further drill string rod of the assembly.

Drill string joint design

A drill string including an elongate hollow main length section and a male spigot portion provided at the second end and having an externally threaded section and a non-threaded shank positioned axially intermediate the main length section and the threaded section. The shank includes a transition section positioned adjacent the main length section or a radially projecting shoulder at the second end. The transition section has an outside diameter that increases in a direction from the male spigot portion to the main length section or the shoulder. The cross-sectional shape profile of the outer surface of the transition section in the plane of the longitudinal axis has a segment of an ellipse having semi-major axis (a) and a semi-minor axis (b), wherein the ratio of the semi-major to semi-minor axes (a:b) is within the range 2b<a<8b.

Growing community of inventors

Sandviken, Sweden

Anders Nordberg