Note: Descriptions are shown in the official language in which they were submitted.
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Drill Supports for a Drill Hammer
The invention relates to a drill support for a drill hammer as per the
preamble of Claim 1. Such a
drill support is designed with a foot for placement on the floor, a holder for
the drill hammer,
and a telescopic, hydraulic cylinder with which the holder can be moved in an
axial direction in
relation to the foot, wherein at least one pressure chamber is placed in the
telescopic hydraulic
cylinder, that allows hydraulic fluid for the deployment of the telescopic
hydraulic cylinder.
Such drill supports, sometimes also described as drill columns, are known for
e.g. from AT
226174. They are used, amongst other things, for the creation of blast holes
in underground
mining and serve the purpose of at least creating a part of the contact
pressure of the drill
hammer and/or of supporting the drill hammer.
There are known pneumatic as well as hydraulic drill supports, especially
those operated by
water hydraulics, whereby the selection of the operational fluid for the drill
supports can
depend on the type of energy used to operate the drill hammer.
Tests have shown that the drilling performance achieved by hydraulically
operated drill
supports, can under certain circumstances, be lower than the drilling
performance of
comparative pneumatically operated drill supports, especially with lower
contact pressures
(wherein under drilling performance the achievable advance per time unit can
be understood).
The function of the invention is to present a drill support with which a
particularly high drilling
performance and high level of reliability can be achieved, even with a
particularly simple design.
The function is solved by means of a drill support as per the invention with
the characteristics of
Claim 1. Preferred designs are given in the attached claims.
A drill support as per the invention is characterized thereby, that it at
least has one spring device
for the axial cushioning of the holder against the foot.
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The basic idea of the invention can be seen therein, that a spring device is
provided in the path
between the holder for the drill hammer and the foot which works together with
the hydraulic
cylinder. This spring device can absorb the elongation of the drill supports
in axial direction,
between the holder and the foot. The invention has recognized that the
increased drilling
performance that is observed with pneumatic drill supports could be based on
the cushioning
effect that takes place with pneumatic drill supports because of the
compressibility of the
gaseous operational fluid. This cushioning effect results in the reaction time
being lower when
compared to that of a hydraulic drill support, which in turn could accompany
higher drilling
performance, especially with lower contact pressures. As against this,
hydraulic drill supports
are often carriers as compared to pneumatic drill supports because of the lack
of compressibility
of the operational fluid and therefore slower with lower contact pressures.
Based on this
knowledge, the invention has planned additionally of providing a spring device
for the hydraulic
drive. Because of this additional spring device, reaction times with hydraulic
drill supports that
correspond to reaction times of pneumatic drill supports can be achieved. As a
result,
particularly high drilling performance can be achieved by the invention,
without having to
abandon the especially tough and reliable hydraulic drive concept.
It is highly preferred that the spring device is provided and/or works in
series with the pressure
chamber. This design adds to the elongation caused by the expansion of the
spring elements
and an elongation caused by the expansion of the pressure chamber. With such
serial
connection, a particularly good reduction in reaction time is achieved.
For example, it can be planned that the spring device has at least one solid
spring, esp. a metal
spring. This can be an advantage with a view on the construction expenses.
Example, the solid
spring can be a metal spring. The solid spring can especially be a coil spring
or a plate spring.
Alternatively or additionally it can be planned, that the spring device has at
least one gas
pressure spring. In the case of such a gas pressure spring, a gas, especially
air is used to prepare
the spring force. Such a gas pressure spring can produce a convenient path.
Moreover a gas
pressure spring can be particularly reliable, especially in long-term
operation.
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As long as a gas pressure spring is provided, it would be helpful to see that
the gas pressure
spring has a spring gas volume that lies outside the hydraulic cylinder and/or
pressure chamber
of the hydraulic cylinder. Accordingly, the gas pressure spring must have
spring housing in which
the spring gas volume is located and which is in fluid connection with the
pressure chamber
through a line link. Such an arrangement is advantageous with regard to
maintenance expenses
because the gas pressure spring and the hydraulic cylinder can be serviced
separately.
Alternatively or additionally it can be planned that the gas pressure spring
has a spring gas
volume which is located in the pressure chamber of the hydraulic cylinder.
This helps in
achieving a highly compact arrangement.
The invention also relates to a drilling device with a drill support as per
the invention, and a
pressure source for impacting the pressure chamber of the hydraulic cylinder
with pressure
fluid. The pressure fluid can preferably be water, but could basically also
just be hydraulic oil.
The hydraulic cylinder is preferably a double-effect cylinder so that it can
be moved in and out
hydraulically.
From the practical point of view, the drilling device has a drill hammer
placed on the holder of
the drill support. The drill hammer can for e.g. have an electro-pneumatic
drive.
The cushioning device is preferably placed on the drill support resulting in a
simple and compact
arrangement.
In addition it is good to at least plan one valve with which the flow of
pressure fluid between the
pressure source and the pressure chamber can be influenced. Through such a
valve the drawing
out of the drill support can be controlled in a simple manner. Here it is
preferred that the spring
device has at
least one gas pressure spring, wherein the valve is placed between the gas
pressure spring and
the pressure source. In such an arrangement, the gas pressure spring can also
be effective when
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the valve is controlled shut or is greatly reduced in its profile. It is also
practical if the valve is
placed between the gas pressure spring and/or the pressure chamber in the line
link.
The invention is explained in detail as follows with the help of preferred
sample designs, which
are shown in the attached diagrams. The diagrams show:
Fig. 1: A partly cut profile of an initial design of a drilling device with a
drill support as per the
invention; and
Fig. 2: A partly cut profile of a second design of a drilling device with a
drill support as per the
invention.
A first design of a drilling device as per the invention is shown in Figure 1.
The drilling device
just shows a drill hammer 3 as well as a drill support 1 on which the drill
hammer is fixed and
which can brace the drill hammer 3 and support a drive of the drill hammer 3.
The drill support 1 has, on one end, an eye-like holder 22 on which the drill
hammer 3 is fixed in
a hinged manner. At its other end the drill support has a foot 11 which is
standing on the floor
8. The drill support 1 further has a hydraulic cylinder 20 which is placed
between the holder 22
and the foot 11, and with which the holder 22 can be adjusted in an axial
direction 6, relative to
the foot 11. Accordingly, on drawing out of the hydraulic cylinder 20, the
drill hammer 3 is
moved away from the floor 8.
The hydraulic cylinder 20 has a cylinder housing 29 and a piston 28 that can
be moved within. In
the sample design presented, the holder 22 on the cylinder housing 29 and the
foot 11 are
arranged on the piston 28. Basically, however, a reverse arrangement is also
possible in which
the holder is attached to the piston and the foot to the cylinder housing. The
piston can be
made in multiple parts and/or telescopic.
The hydraulic cylinder 20 is designed as a double-effect cylinder and
therefore shows a first
pressure chamber 25 that has pressure fluid 40 for pulling out of the
hydraulic cylinder 20, and
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a second pressure chamber 35 with pressure fluid 40 meant for driving in of
the hydraulic
cylinder 20. A pressure source 60 is connected to the hydraulic cylinder 20
with which pressure
fluid 40, especially water, can be introduced into the pressure chamber 25 or
35 for targeted
pulling out or driving in of the hydraulic cylinder. In the line link 66 which
runs between the
pressure source 60 and the pressure chamber 25, a valve 65 is placed to
influence the fluid
exchange between the pressure source 60 and the pressure chamber 25. This
valve 65 can be
built as a directional valve or as a combination of directional and control
valve.
In order to make it clearer in the diagrams, the pressure fluid 40 is shown
only in the first
pressure chamber 25. In a double-effect hydraulic cylinder 20, however,
pressure fluid would
normally be found also in pressure chamber 35.
In order to reduce the reaction time of the drill support 1 and thereby to
improve the drilling
performance, a spring device 50 is considered which in the design sample in
Figure 1 is a gas
pressure spring 54. In the design sample of Figure 1, the gas pressure spring
54 is arranged
outside the cylinder housing 30 and/or the pressure chamber 25. It shows a
spring housing 56
the inner chamber of which is connected with the pressure chamber 25 in a line
link. On the
inside of the spring housing 56 is spring gas volume 55, especially air, which
creates the desired
resilience. The gas pressure spring 54 of Figurel is therefore made like a
bubble storage.
In another design variation not presented here, the gas pressure spring can
also be formed in a
way that the spring gas volume is placed within the pressure chamber 25, thus
doing away with
the external spring housing 56 and the line link 57.
A further design sample of a drilling device as per the invention is presented
in Figure 2. The
design sample of Figure 2 varies from that of Figure 1 only with regard to the
arrangement and
placement of the spring device. For the other remaining elements one can
therefore refer to
the above description of Figure 1.
In the design sample of Figure 2, the spring device 50' is a solid spring 52,
for e.g. a coil spring.
In the design sample presented, the spring device 50 is placed in the course
of the piston 28 i.e.
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between the pressure chamber 25 and the foot 11. The spring device could also
be placed for
e.g. between the holder 22 and the pressure chamber 25.
In both design samples of Figure 1 and Figure 2, the spring devices 50 and 50'
work in series with
the pressure chamber i.e. the spring devices 50 and 50' can accept elongations
between holder
22 and foot 11 without having the pressure fluid from the pressure chamber 60
lead into or out
of the pressure chamber 25. Therefore if during operation of the drilling
device crushes arise in
the axial direction 6 from the drill hammer 3 and/or holder 22 towards the
foot 11, these can be
cushioned by the respective spring devices 50 and 50'.
