Publication Date: 2004-Feb-24
The IP.com Prior Art Database
Nigel Roberts: CONTACT [+2]
A drilling rod for use in a rock drill has a shank adapter portion and the rod itself all formed as a single, integral component. A drill bit can be fitted at the outer end of the rod.
This invention relates to a drilling rod, particularly for
use in rock drills, and particularly for use in rock drills
which operate with a percussive/rotary drilling action.
Such rock drills have a chuck to which a rock drill is
Conventional rock drills are made up of a number of
components connected by screw threaded joints. Typically
these components are (a) a shank adapter which fits in the
chuck of the rock drill, (b) an elongated drill rod, (c) an
internally threaded coupling sleeve which connects the
shank adapter and the drilling rod, and (d) a drill bit
which is threaded onto the remote end of the drilling rod.
In this construction, both the shank adapter and the
adjacent end of the drilling rod have male threaded ends.
It is however also known to form the drill rod end with a
female threaded end so that the drilling rod can screw
directly onto the shank adapter, or vice versa.
However, the use of multiple threaded connections leads to
losses in the energy and forces transmitted from the rock
drill to the bit, and also introduces a source of wear
which can be damaging to the service life of the components
involved. Threaded connections are also a source of metal
fatigue which can lead to premature failure.
According to the present invention, there is provided a
drilling rod for use in a rock drill, the rod comprising a
single component having at one end a drive portion for
directly engaging in a chuck of a rock drill, at the other
end a thread for receiving a bit, and a rod portion between
the ends, the rod having an internal passage for flushing
medium which leads from a region of the rod portion
adjacent the drive portion, through to said other end of
the rod, with said region of the rod portion being
cylindrical and having a radial passage through the rod
wall communicating with the internal passage.
Preferably the drive portion has splines to engage in a
rock drill chuck, and the splines have an external diameter
greater than that of the rod portion.
The rod can be manufactured from two lengths of bar stock
which are originally friction welded together and then
The thread portion at said other end may be a male thread,
or a box with an internal female thread.
Preferably the rod portion is at least four times longer
than the drive portion. Typically, the rod will have a
length of between two and six metres, with an average
length being in the order of five metres.
The rod portion preferably has a radial hole for the entry
of flushing fluid, in a manner know per se for shank
The invention will now be further described, by way of
example, with reference to the accompanying drawing, in
Figure 1 shows a drill rod according to the
invention, with the central portion (of
variable length) omitted; and
Figure 2 shows a friction welded blank from which the
rod can be made.
In Figure 1, the rod 10 has a drive portion 12, a rod
portion 14 and a thread 16. The drive portion 12 is formed
with splines, and the precis...