Improvements in Percussion Borers.
Year: 1893

page_text: Date of Application, 16th Sept., 1893
Complete Specification Left, 13th Feb., 1894-Accepted, 17th Mar., 1894
Improvements in Percussion Borers.
A communication by CAMILLE BORNET, of 10, Rue St. Ferdinand, Paris, in the
Republic of France, Engineer.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool and 6, Bank Street,
Manchester, both in the County of Lancaster and 323 High Holborn in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this
invention to be as follows:-
This invention relates to improvements in percussion borers, and has for its object
to allow of the injection, at the bottom of the bore hole and at each stroke of the
borer, of a certain quantity of water under pressure intended to ensure the
continuous removal of the particles of rock detached by the drill, the useful effect
of which is increased to a very considerable extent.
The invention consists in an arrangement for supplying water to the end of the
borer, in combination with the use of a hollow boring rod and of a drill perforated
along its entire length, which drill directs the water under pressure to the bottom
of the bore hole where it penetrates by successive injections, and produces at each
stroke the perfect cleansing of this hole.
For this object, the head of the borer is terminated by a screwed part on which
the arrangement for supplying the water under pressure is fitted, such water after-
wards traversing the hollow boring rod.
This part for supplying the water is hollowed out internally so as to form a
circular chamber through the centre of which the boring rod passes, and stuffing
boxes arranged on both sides of this chamber prevent any escape of the water
to the outside.
On the other hand, the boring rod is perforated with a longitudinal central bole
which connects at the rear, by means of an oblique passage, with the water supply
chamber, and, in the same way, the drill which is fitted on the end of the boring
rod is perforated along its whole length so as to allow the water under pressure to
be discharged quite close to its extremity or cutting point.
By taking care to make the water supply chamber considerably shorter than the
stroke of the boring rod, and by arranging the above mentioned oblique passage
in such a way that it only communicates with this chamber at the moment when the
boring rod has reached the end of its stroke, the result is that the injection of
water under pressure will only take place at that moment, which has the double
advantage of effecting a very considerable economy in the quantity of water
consumed, and of preventing the hollow part of the drill near the cutting point
from becoming filled with the debris of rock at the moment of the impact of the
drill.
By varying the length of the water supply chamber, the duration of this
injection of water under pressure may be varied, and it has been found that, by
supplying the water only at the end of the forward stroke of the drill and at the
commencement of its retrograde movement, the best conditions are realised for
arriving at the desired object.
In order that no escape of water may take place at the point where the boring
rod receives the hollow drill, a special tool holder employed, which is provided,
in addition to the pressure screw acting on a gripping block, with a stuffing box
adapted to prevent any escape of the liquid.

page_text: Finally, in order to avoid any obstruction of the hole for discharging the water
at the end of the drill, the central passage for supplying the water is made to
discharge preferably at the side of and a little behind the cutting point of
such drill.
In case the borer is operated by means of compressed air, and water under
pressure for producing the injection is not at disposal, low pressure water may be
supplied to the chamber hereinbefore mentioned, and the oblique passage formed
in the rear of the boring rod may be arranged in such a way that it penetrates at
each stroke to a certain extent into the interior of the cylinder of the borer; in
this manner, the pressure of the compressed air which is produced behind the
piston after each stroke. of the drill will act on the water which may have been
introduced therein at the moment of its passage into the chamber, and will force it
to flow through the boring rod and the drill, and to be forcibly discharged at the
bottom of the bore hole in order to ensure the instantaneous cleansing of the latter.
In all the cases, the shaft of the drill may be made in one piece along its entire
length, or be made in two parts; in the latter case, the larger part of this shaft
may be made in such a way as to have at its end a screwed part on which the
actual tool is fitted, which may be thus very rapidly removed and replaced; the
direction of the screw thread being arranged in such a way that the rotation of
the drill tends to constantly tighten it whilst working.
Dated this 15th day of September 1893.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
Improvements in Percussion Borers.
A communication by CAMILLE BORNET, of 10, Rue St. Ferdinand, Paris, in the
Republic of France, Engineer.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors 6 Lord Street, Liverpool and 6 Bank Street, Manchester, both
in the County of Lancaster and 323 High Holborn, in the County of Middlesex,
Civil Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
This invention relates to improvements in percussion borers, and has for its object
to allow of the injection, at the bottom of the bore hole and at each stroke of the
borer, of a certain quantity of water under pressure intended to ensure the
continuous removal of the particles of rock detached by the drill, the useful effect
of which is increased to a very considerable extent.
The invention consists in an arrangement for supplying water to the end of the
borer, in combination with the use of a hollow boring rod and of a drill perforated
along its entire length, which drill directs the water under pressure to the bottom
of the bore hole where it penetrates by successive injections, and produces at each
stroke the perfect cleansing of this hole.
The injection of water under pressure has already been employed with the same
object, such water being supplied by means of a tube placed laterally to the drill,
and penetrating more or less deeply into the bore hole, but the amount of water
used is considerable, and the result obtained is imperfect, the particles of rock at
the bottom of the hollow not being removed after each stroke of the drill and
consequently impairing its action at the time of the subsequent stroke.
The invention will now be described in detail, reference being made to the
accompanying drawing, on which,
Figure 1 is a longitudinal section of the apparatus ;

page_text: supplying water;
Figure 3 is a side elevation of this modification;
Figure 4 is an end view;
Figure 5 is a longitudinal section of a hollow drill in two parts.
In the arrangement shown in Figure 1, the head A of the borer is terminated
by a screwed part on which the arrangement B for supplying the water under
pressure is fitted, this part B being held by a counter-nut G and provided with a
regulating tap C.
This part B for supplying the water is hollowed out internally so as to form a
circular chamber D through the centre of which the boring rod T passes, and
stuffing boxes E E' arranged on both sides of this chamber prevent any escape of
the water to the outside.
On the other hand, the boring rod T is perforated with a longitudinal central
bolet which has at the rear an oblique passage t¹ which connects at each stroke of
the borer with the water supply chamber, and, in the same way, the drill F which
is fitted on the end of the boring rod T is perforated along its whole length with a
hole so as to allow the water under pressure to be discharged at a point e quite
close to its extremity or cutting point N in order not to be obstructed by the
fragments of rock detached by this cutting point.
By taking care to make the water supply chamber D considerably shorter than
the stroke of the boring rod, and by arranging the above mentioned oblique
passage in such a way that it only communicates with this chamber at the
moment when the boring rod has reached the end of its stroke, the result is that.
the injection of water under pressure will only take place at that moment, as may
be seen in Figure 1, in which the boring rod T is shown at the end of its forward
course. This arrangement has the double advantage of effecting a very considerable
economy in the quantity of water consumed, and of preventing the hollow part e of
the drill near the cutting point from becoming filled with the debris of rock at the
moment of impact of the drill.
By varying the length of the water supply chamber D, the duration of this
injection of water under pressure may be varied in the same proportion.
In order that no escape of water may take place at the point where the boring
rod T receives the hollow drill F, a special tool holder H is employed, which is
provided, in addition to the pressure screw L acting on a gripping block K, with a
stuffing box adapted to prevent any escape of the liquid.
Finally, in order to avoid any obstruction of the hole for discharging the water
at the end of the drill, the central passage for supplying the water is made to
discharge preferably at the side of and a little behind the cutting point of such
drill.
In case it be desired to alter at will the course of the boring rod, the oblique
passage t' of this rod is arranged in such a way that it connects with, or passes
through, the chamber D once during the forward stroke of this rod, and a second
time during the retrograde movement. The modification of the apparatus which is
shown in Figures 2, 3, 4, shows the application of this arrangement.
In this modification, the water supply arrangement B, together with its tap C,
is fitted to the head A of the burer by means of bolts, and it is also provided with
two stuffing boxes E E¹.
In Figure 2, the passage passes into the water supply chamber D during its
forward movement, and passes beyond this chamber in order to reach 9, for instance,
then during the return of the boring rod T, this passage comes a second time into
the chamber D in order to return to the position shown on the drawing. There
are thus produced in this case, two injections of water per stroke, one taking place
a little before contact of the tool with the rock, and the other a little after this
contact, the complete cleaning of the bore hole being obtained in the manner
previously described.
In case the borer is operated by means of compressed air, and water under

page_text: pressure for producing the injection is not at disposal, low pressure water may be
supplied to the chamber D hereinbefore mentioned, and the oblique passage t
formed in the rear of the boring rod may be arranged in such a way that it
penetrates at each stroke to a certain extent into the interior of the cylinder of
the borer; in this manner, the pressure of the compressed air which is produced
behind the piston after each stroke of the drill will act on the water which may
have been introduced into the passage at the monent of its passage into the
chamber D, and will force it to flow through the boring rod and the drill, and to
be forcibly discharged at the bottom of the bore hole in order to ensure the
instantaneous cleansing of the latter. In all the cases, the shaft of the drill may
be made in one piece along its entire length, or be made in two parts, as shown in
Figure 5; in the latter case, the hollow part F of this shaft may be made in such
a way as to have at its end a screwed part on which the actual tool is fitted, which
may be thus very rapidly removed and replaced; the direction of the screw thread
being arranged in such a way that the rotation of the drill tends to constantly
tighten it whilst working.
By this means, an important loss of expensive metal is avoided, when, consequent
on wear and tear, the tool is no longer of sufficient length, and has to be thrown
away.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :-
1. In a percussion borer, a chamber for supplying water under pressure, attached
to the head of the borer, in combination with a hollow boring rod, and a drill
perforated along its entire length, with the object of producing at the bottom of
the bore hole and at each stroke of the drill one or two automatic injections of
water in order to ensure the perfect cleansing of the bore hole substantially as
.hereinbefore described.
2. In a percussion borer, the combination with a circular chamber such as D
for supplying water under pressure, and with a hollow drill such as F, of a boring
rod T, the internal perforation of which is placed in communication with the said
chamber D by means of an oblique passage t' arranged in such a way that at cach
stroke of the drill a single central injection of water is produced at the end of the
stroke of the drill or two successive injections one during the forward and the
other during the retrograde movement of the above drill substantially as herein-
before described.
3. Ju a percussion borer operating by means of compressed air, and containing a
chamber D for supplying water under pressure, a hollow boring rod T and a hollow
drill F an oblique passage t' placing the water supply chamber D in communica-
tion with the boring rod T, which passage is arranged in such a way as to penetrate
at each stroke into the body of the borer in order to allow the compressed air
contained therein, to energetically inject to the bottom of the bore hole the water
which has penetrated into the hollow boring rod at each stroke of the drill
substantially as herein before described.
4. In combination with a borer provided with a tubular boring rod receiving
water under pressure, a drill formed of a steel bar perforated along its entire
length, and capable of being made in one or two pieces substantially as hereinbefore
-described.
Dated this 12th day of February 1894
WM. P. THOMPSON & Co.,
Agents.