Improved Grab for Lifting the Cores Formed by Tubular Rock- drills, or Broken or Detached Drill-rods or Boring Tools from Bore-holes.
Year: 1894

page_text: Date of Application, 2nd June, 1894-Accepted, 14th July, 1894
5
COMPLETE SPECIFICA
n Improved Grab for Lifting the Cores Formed by Tubular Rock-
drills, or Broken or Detached Drill-rods or Boring Tools from
Bore-holes.
I, PER ANTON CRELIUS, of Smedjebacken, in the Kingdom of Sweden,
Engineer, do hereby declare the nature of this invention and in what manner the
ame is to be performed, to be particularly described and ascertained in and by
he following statement :-
My invention relates to a grab for lifting the cores formed by tubular rock-drills
from bore-holes, the grab being also applicable for lifting broken or detached drill-
rods from such holes.
The grab can be used in conjunction with a tubular drill for lifting the core
formed thereby, or it can be used for lifting the core from a bore-hole formed by
an independent drill-rod.
In the accompanying drawing,-
Figure 1 is a vertical section shewing my grab as used in conjunction with a
tubular drill; and,
Figure 2 is a similar view shewing the grab as used independently of a
drill-rod.
The grab consists of a socket A adapted to be screwed on to the lower end
of a boring rod and having formed therein holes or channels B extending from
the upper and outer edge of the socket downwards and inwards, the number of
which holes or channels in the example shewn in the drawing would be three.
These channels form on the inner surface of the socket openings, the greatest
width of which is less than the diameter of the channel. In each hole is a
ball C of steel or other hard material which when it rests on the bottom of the
Rollers may be used instead of balls.
hole partly projects into the socket.
These balls offer no obstacle to the lowering of the tube to which the grab is
attached as they are then actuated by the core and can rise in the upper parts
When on the other
of the holes B and at the same time recede from the core.
hand the tube is lifted the balls will descend and be clamped between the socket A
and the core so that the latter can be lifted.
As shewn in Figure 1 the grab is represented as arranged in conjunction with a
tubular drill, the said grab being provided with a screw-threaded socket to
receive the drill. When the grab is used independently the lower edge of the
socket is bevelled on the inside, as shewn in Figure 2, in order that the grab
may be easily brought over a core in the boring hole. When this has taken
place and the socket is lifted the core follows for the reason described above.
It will be easily understood that (the grab being of sufficient width) it can
The holes or channels B
be passed over the drill-rod and serve to lift the same.
can obviously be arranged directly in the drill-rod or in the tubular drill or bit.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
0 claim is:-
1. A grab for lifting the cores formed by tubular rock-drills, or broken or
detached drill-rods or boring tools from bore holes consisting of a socket or tube
having one or more holes or channels passing obliquely downwards and inwards to
the inside of the socket or tube, each of such holes or passages containing a bal
15 or roller which in its lowest position projects through the inner opening so that the
balls when the socket or tube is lifted will be clamped and lift the core, or the

page_text: drill-rod, but when the socket or tube is lowered the said balls will be pushed
upwards in the holes or channels, substantially as herein before described.
2. The improved grab for lifting the cores formed by tubular rock-drills or
broken or detached drill-rods or boring-tools from bore-holes hereinbefore described
and illustrated in the accompanying drawing.
Dated this 2nd day of June 1894.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.