Note: Descriptions are shown in the official language in which they were submitted.
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~PtCIFIC~TION
This invention relates to an hydraulically operated
striking apparatus. ~ore particularly, this invcntion tel~es
to a striking apparatus operated by pressure liqu;d, precrably -~
or a rock drill, the said striking apparatus comprising a body
to which the tool can be movably attached, a striking piston
moving to and fro in the cylinder space and a liner type dis~
- tributing valve concentric with the piston, moving to and fro
in the valve space and aimed for chanqing the direction of the
motion of the piston. Pressure liquid from an annular space
O defined by the body of the drill, the piston and the distri~
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~ buting valve, which has been used to operate the valve is
employed to operate an hydraulic rotating motor. -
- Various rock drills have been suggested which are operated ~ :~
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by pressure liquid. One such rock drill is described in copend~
- ing Cdn. patent application Serial ~o. 225,581, filed Oct. 25,
1977, ln the name of P. Salmi and P. Raunio, which rock drill
comprises a body to which a tool can be attached, a strik~ng
-piston moving to and fro in a cylinder space, a distributing ~ ;
valve Iocated in a distributing valve space and an hydraulic
~o motor rotating the tool. The ~iston and the distributing valve ~ ;
are operated by pressure liquid. The object of the distri-
buting valve is to accomplish the motion of the piston to and
~ro.
There are various otber ways to arrange the mutual opera~
tion and placement of the piston and the distributing valve as
oan be seen! for example, from U. 9. patent 3,322,210, and ~ ~
Prench patent 1,431,835. Characteristic of such arrangemFnts ~ ;
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is that the press-lrc liquid causes the distributing valve to
move from one posltion to another, whereafter the peessure
liquid flows into an outlet canal. The pressure liquid neede~
by the rotating motor is conveyed through a separate canal from
a pressure liquid source which serves both the striking appa-
ratus and the rotating motor which rotates the tool. From the
rotating motor the liquid flows into the outlet canal.
The known arrangements described above have various dis-
advantages because the pressure liquid escaping from the
0 distributing valve space does not accomplish any ~urther
useful work. Thus, the economy of the pressure liquid is
poor~
The objects of this invention include the elimination of
the foresaid disadvantages and to provide a striking apparatus,
wherein the total consumption of liquid decreases because the
pressure liquid can be better utilized in the machine, the tube
- for conveying liquid from an outside pump to the rotating motor
can be eliminated, and overloading of the machine due to too
strong resistance to rotate is eliminated.
These and other objects are achieved with the present
invention, which comprises, in a striking apparatus of the
type having body means having an interior space, striking
piston means axially slidable between first and second positions
within said interior space, said piston means and said
body means defining an annular valve space, distributing
valve means slidably disposed in said annular valve space
; and being axially slidable between first and second positions,
and means for supplying fluid under pressure to operate said
piston means and said valve means, the improvement comprising
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means in said body means defining a body out]et m~ans for
conducting fluid under pressure from said body means after
said fluid has actuated said distributing valve means, an
hydraulic rotating motor, and means for conveying said fluid
under pressure from said body outlet means to said hydraulic
~otatiny motor to rotate said motor.
Thus, the present invention eliminates prlor disadvantages
by leading the hydraulic oil, which moved the distributing
valve, to the rotating motor of t~e rock drill for operating
this and thus accomplishing useful work. An apparatus accord-
ing to the invention is possible because it has been proved
that the pressure and amount of the escaping liquid are appro- ~ -
priate to rotate the rotating motor under normal drilling
circumstances. If the resistance of the drill to rotate
increases, for example, in a broken rock, also the pressure
of the oil in the outlet canal increases. When the resistance
to rotate reaches a certain point, the pressure of the oil
in the outlet canal has grown so high that the distributing
valve can no longer move. Thereby also the movement of the
~o piston stops. Thus, a too high resistance to rotate is pre-
vented from overloading the machine.
In order that the manner in which the foregoing and other
objects are attained in accordance with the present invention
can be understood in detail, a particularly advantageous
embodiment thereof will be described with reference to the
accompanying drawings, which form a part of this specifica~
tion, and wherein:
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Fig. 1 is a side elevational vicw oE the striking ~ppa-
ratus of the present invention partly in section, showiny the
piston in its lowest position at the end of a work stroke;
Fig. 2 is a side elevational vicw of the striking appa-
ratus of the present invention partly in section, showing the
piston at the beginning of a work stroke and the communication
between the distributing valve space and the outlet canal; and
Fig. 3 is a sectional view of the apparatus taken along
line 3 3 of Fig. 1 and looking in the direction of the arrows.
(0 In this application, the terms "down", "under" and "lower"
mean that end of the apparatus to which the tool is attached
and "up", "above" and '!upper", the opposite end of the apparatus.
. .
Referring now to Fig. 1, the piston 2, the parts of
which are a rod 12, a flange 13 and an extension 14, is shown
near its second, lower position in the cylinder space of
the body 1 where it slidably moves to and fro. A cylinder
space is present below the flange 13, which space is called .
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the lower space 5 and the cylinder space above the flkange
13 is called the upper space 15. At the upper end of the
20 extension, there is flange 16. While moving to and fro,
the piston 2 strikes on the tool 17. If the tool 17 is not
in place, the piston 2 stops in the absorber spac e 21 which -
is closed by the flange 13 when it is in its lowermost position
whereby the pressure in the absorber space rises high enough
to stop the motion o~ the piston. As seen in Fig. 2, the
space 13 for the flange 16 of the extension 14 connects the
upper space 15 with the inlet canal 20 through the canal
~6 when the piston 2 is coming close to its upper turning
point. A flushing tube 24 leads from nipple 23 through
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the striking apparatus ~or conveying a flushing liquid, such
as watee, into the bore of the tool or drill steel. For
this purpose a water hose may be attached to nipple 23.
The pressure plpe conveying the pressure liquid into the
apparat~s can be connected to the nipple 22, and correspondinyly,
the outlet pipe to the nipple 25. From the nipple 22 in
the body of the apparatus begins the inlet canal 20 which
leads to the lower space 5, the upper space 15 and the pressure
accumulator 21. The flows of the liquid and the changes
lo in pressure are balanced by the accumulator 21.
The inlet canal 20 is connected with the lower space 5
and through the distributing valve with the upper space 15.
Differences in diameter of the piston 2 are such that the lower
surface of the flange which is continuously under pressure is
smaller than the upper surface, the pressure against which is
either cut off or opened by the distributing valve 3 and the
extension 14 of the piston. When the upper space 15 is under
pressure, the piston 2 moves down. Correspondingly, when the
upper space 15 is connected to the outlet canal 27, the piston
moves up.
The liner type distributing valve 3 moves in the space 6
which is in the body 1 immediately around the part of the
cylinder spaces 5 and 15 in which the flange 13 of the piston
moves. Between the lower space 5 and the distributing valve
space 6, there is an inwardly protruding annular member 2S, the
cylindrical inner surface of which forms part of the cylin
drical wall of the cylinder spaces 5 and 15 around the flange
of the piston.
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The part of ~he space 6 which is below the distributing
valve 3 i5 connected with the lower space 5 by the canals 4 in
the piston when the piston'2 has moved down enough. In the
distributing valve 3, there are also openings 29 and 30 which
are opposite to the outlet canals 9 and 9a from time to time.
When the distributing valve 3 is high enough, as ln Fig. l,
the liquid can flow from the upper space 15 through the open-
ing 30 in the distri~uting valve 3 into the outlet canal 9a.
The sizes of the upper and lower ends 8 and 7 of the distri- ,,
buting valve 3 are such that when the distributing valve
space 6 in the lower end of the distributlng valve 3 is
connected through the canals 4 with the lower space 5 under
pressure, the force caused by the pressure,against the lower
surface 7 of the distributing valve 3 moves the valve up. The
reason,for this is that the upper surface 8 of the distri-
.
~ buting valve is smaller than the lower surface 7 and the
-~ pressure against both surfaces is the same.
; .
Fig. 1 presents a situation where the piston 2 has just
struck and is now starting its return movement. The distri-
~o buting valve 3 is in its uppermost position stopped by theabsorber 31. The pressure from the inlet canal 20 into the
upper space 15 is completely closed and the escape through the
hole 30 into the outlet canal 9a is open. The pressure in the
lower space 5 forces the piston 2 to move up. The distributing
valve space 6 is connected with the lower space 5 by the canals
4 in the piston 2.
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After the piston has struck tool 2, its return movement
begins. The retu~n movement of the piston is at ~irst acceler-
ated while the liquid of the upper space 15 escapes through
the canal 9a into the outlet canal 27. The acceleration
decreases and finally the movement of the piston starts to
slow down while the upper end 32 of the flange of the piston
starts to cholce the flow into the outlet canal 9a, whereby
the pressure in the upper space 15 starts to rise. In order
to prevent it from rising far ove~ the average pressure in
~o the pressure network of the striking apparatus, the flange
16 of the extension 14 of the piston opens the connection
26 from the upper space 15 into the inlet canal 20 a little
before the flange of the piston has completely closed the
connection into the canal 9a. The liquid displaced by the
piston while it is moving flows through the canal 26 into
the inlet canal 20 and is stored in the accumulator 21.
The said connection into the inlet canal is opened when the
lower end 33 of the ~lange 16 of the extension 14 of the
piston 2 has passed the lower edge 34 of the canal 26 and
2O the said connection to the canal 9a is closed when the upper
end 32 of the flange 13 of the piston 2 reaches the upper
edge 35 of the opening 30. When the canal 9a is closed,
the outlet phase into the outlet canal 27 has come to the
end and the speed of the movement of the piston decreases.
When the piston 2 has moved almost to its upper turning point
while the distributing valve 3 is in its upper position,
the canals 4, which are shown in cross-section in Fig. 3,
in the flange 13 connect the distributing valve space 6 through
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the openings 29 in the distributing valve 3 with the outlet
canal 9. Be~ore this the flange 13 has closed the connection
between the lower space 5 and the distributing valve space
6 with the aid of the neck 28 in the body 1, which neck is
located between the lower space 5 and the distributing valve
space 6. When the distributing valve space 6 is connected
with the outlet canal 9, the pressure in the distributing
valve space 6 decreases and the inlet pressure towards the
upper surface 8 of the distributi~g valve 3 makes the distribut-
ing valve 3 move down. .
When the flange 13 of the piston 2 closes the above-
mentioned connection and the canal 4 connects the space 6
through opening 29 with the outlet canal 9, the liquid from
the space 6 flows into canal 9 which communicates fluid under
pressure to hydraulic rotating motor 10 of the rock drill, :
which motor can be positioned either in the front or back
end-o~ the machine. In the accompanying drawings this motor
is only shown schematically. Because the liquid under pressure
is conducted from space 6 to the motor in interrupted fashion,
it is desixable to provide a pressure accumulator 11 connected
to the canal 9 between opening 29 and motor 10. The flow
of pressured liquid from space 6 into canal 9 through which
it is conducted to motor 10, causes rotation of that motor
and rotation of the tool, the pressure fluctuation being
~omewhat smoothed by accumulator 11. The dotted spaces in
accumulators 11 and 21 are pressurized gas, below which is
a membrance and below the membrane is the hydraulic liquid,
i.e., oil. The purpose of the pressure accamulator is to
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equali~e the p~essure variations in the oil system and to make
the operation of the drill smoother.
When the piston 2 is moving upwards, the oil must
always have free outlet of the upper space 15. Thus, when using
the conventional piston construction, the distributing valve 3
should Always start to move downwards a little before the opening
30 is closed while the valve is in its upper position. It is -
very difficult to synchronize these operations when the conven-
tional piston construction is uséd. When using the extension 14
0 of the piston in the above manner, this difficulty is eliminated.
Now the valve 3 can stand still when the flow from the upper
space 15 through the canals 26 and 20 into- the pressure accumu-
lator 21 begins a little before the flow from the upper space 15
nto the canal lla ends.
When the distributing valve 3 is in its upper position,
the distance between the upper end 32 of the flange 13 of the ;~;
piston 2 and the lower end 33 of the flange 16 of the exten-
sion 14 of the piston is longer than the distance between the
upper edge 35 of the outlet opening 30, which is in the dis
2 tributing valve 3 outlet from the upper cylinder space 15, and
the lower edge of the canal 26 leading from the space 15 of the
extensin 14 of the piston 2 into the inlet canal 20 of the
pressure liquid, whereby the connection from the upper cylin-
der space 15 through the space 19 of the extension 14 and the
said canal 26 into the inlet canal 20 of the pressure liquid
opens before the flange 13 of the piston closes the opening
30 in the distributing valve 3, which leads into the outlet
canal 9a.
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In Fig. 2 the piston 2 is ready to start its down stroke.
At first the upper space 15 is filled through the canal 26 and
the space 19 of the extension of the piston and simultaneously
through the circular canal opened by the distributing valve 3.
When the piston 2 has moved down enough, the lower end 33 of
the flange 16 of the extension 14 of the piston closes the
connection from the upper space 15 through the canal 26 into
the inlet canal 20. The distributing valve 3 is stopped in
its lower position by the absorber. When the piston 2 is
moving down, it opens the connection between the lower space 5 `~
into the distributing valve space 6 through the canals 4
slightlyf be~ore the piston 2 strikes at the tool 17. The
pressure in the distributing valve space 6 rises and moves the -~
distributing value 3 up. The connection from the inlet canal
:- ~.
20~into the upper space 15 is closed and the opening 30 comes ; ~-
opposite to the outlet canal 9a. The distributing valve 3 is
stcpped by the absorber 31 in the position shown in Fig. 1.
The striking apparatus thus described offers many
advantages in that it is simple in design, which results in
the least possible amount of movement and wear of parts. In
addition to certain advantages described`in aforementioned
application Serial No. 2Z5,581, the present invention provides
the following~
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1. Total consu~ptlon of liquid decreases because the
pressure liquid can be better utilized in the machine.
2. The pressure canal from the space 6 to the rotating
motor can be drilled into the body of the machine and thus
no tube is needed for conveying liquid from an outside
pump to the rotating motor.
3. Overloading of the machine due to too strong resistance
to rotate is eliminated.
The invention is not limited to the rock drill
~o arrangement which has been described as an example in this
application, but it can be used in all hydraulic drill
arrangements which comprise a striking piston, a pressure
liquid-operated distributing valve guiding the piston and a
hydraulic rotating motor.
While one advantageous embodiment has been chosen
to iliustrate the invention, it will be understood by those
skilled in the art that various changes and modifications
can be made therein without departing from the scope of the
invention as defined in the appended claims.
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