Arrangement in a drilling apparatus The invention relates to an arrangement in a drilling apparatus, at the drilling end of which there is a drilling device, that includes at least drilling means and hammering means as well as preferably flushing means, to drill a hole by means of the drilling means, preferably assisted by a flushing medium, lead to the flushing means from the flushing medium system of the drilling apparatus and made functional by a transmis- sion arrangement situated at the driving end of the drilling apparatus, by using a feeding motion along the longitudinal axis of the drilling device and rotational motion around the longitudinal axis as well as hydraulic fluid being led to the hammering means from the hydraulic system of the drilling apparatus to achieve a to-and-fro or a like hammering motion. The drilling device has jointing means for attachment of a drill rod removably to the same for increasing the drilling depth of the drilling apparatus, which drill rod comprises a casing structure equipped with corres- ponding jointing means, at least partly inside of which there has been arranged a flow assembly to lead hydraulic fluid and/or flushing medium, and whereby in connection with the jointing means there has been arranged coupling means for connecting the flow assembly of a component being treated at the moment, such as of a drilling apparatus or of a drill rod, to a corresponding flow assembly existing in the drilling device and/or in a second drill rod and/or at the driving end of the drilling apparatus. The coupling means include locking means, that while detaching/at- taching the component by influence of pressurized medium, essentially self-powered close/open at least the flow openings transmitting hydraulic fluid.

Drilling apparatuses such as described above, in which the hammering means operated by compressed air, are

placed advantageously at the drilling head of a down- the hole drill, have already been known for a long time and they have also been widely used in mineral industry. In this case an advantage of the hammering means being placed in the hole is, that the strokes of the same are aimed directly to the drill bit, whereby it is possible to increase energy loss and unnecessary wearing of components belonging to the arrangement to lower level than in solutions, in which the hammering means are placed in the rear end of the drill rods. In connection with pneumatic drilling machines compressed air is usually used to flush drilling waste, also.

However, it is not benefical to use the drilling machine with compressed air, because a very high power of the compress unit is thus needed. In addition to that the efficiency of a pneumatic system is clearly lower than the same of a hydraulic system.

On the other hand use of hydraulic drilling machine is known previously from e.g. the applicants Finnish Patent Applications, the numbers of which are 921777 and 933024. The former application is directed parti- cularly to a hydraulic oil to be used as a pressurized medium for the hammering means of the drilling device, that is organic and based on natural biological metabolism. In the application in question there has been presented on the other hand certain technical constructions, also, which may particularly well be adapted in the purpose in question. In the parts belonging to the drilling apparatus there has been arranged in this case coupling arrangements, which while detaching successive parts of the drilling apparatus close at least the flow openings of the ducts transmitting pressurized medium, that are being opened. In this case, when detaching parts from each other, hydraulic fluid remains inside the loosened parts, which in this case act in principle as reser- voirs. When connecting the parts again, hydraulic

fluid inside the same is thanks to this immediately ready for use and it is not needed to feed compensa- ting hydraulic fluid for this reason. In the presented construction the coupling arrangements are carried out by spring loaded locking arrangements being placed in the couplers of the parts, which move independently in relation to each other during installation measures.

The drilling apparatus being represented in the latter application (933024) is based for its part on the fact, that the drilling device has a valve and control flow assembly to achieve the hammering motion, that controls the flow of hydraulic fluid in the hammering means, and a piston assembly carrying out the said hammering motion by influence of the above as well as an accumulator assembly storing hydraulic fluid, that has been arranged in the longitudinal direction in connection with the hammering means, such as centri- cally in the same longitudinal axis between the piston assembly and the valve and control flow assembly.

Use of the new pressure medium being represented in the application 921777 has gained remarkable intrest as well as footing in the markets, though very exten- sive research and development activities have been taken for the part of the structures being represented in the application in question. Particularly the coupling arrangements above, which have been found very useful in practical solutions, have thus been under particular examination. This is first of all because of the fact, that when a usual threading has been used as the jointing arrangement between the drill rods certain constructive problems are caused concerning the leading of hydraulic fluid and flushing medium from one part to another. Slowness of instal- lation measures is caused as well, because the drill rods must be "screwed" several rounds in relation to each other. On the other hand in the Finnish Patent Application mentioned above there has been presented

a solution, also, that is functional in principle particularly from the point of view of the coupling arrangements as well, which is, however, based on constructions, that are built-in with e.g. the drill rods, that is why manufacturing costs of the parts in question are disproportionately high. Because of complicated structures maintenance of the parts is not very profitable either economically, in addition to which, when the drill rods or the threadings or coup- ling arrangements belonging to the same e.g. get partly broken, the drill rod must be replaced in a traditional way with a new one as a whole.

To avoid the problems above the Finnish Patent Appli- cation No. 944291 discloses furthermore one new solution, which is based on that, that e.g. the drilling device and each drill rod comprises end parts, that are attached removably to the same remova- ble by means of quick-locking principle, and in connection with which there has been arranged at least part of the jointing means, coupling means and/or the flow arrangements. Furthermore by adapting particular- ly a two-ended threading advantageously within the jointing means as quick as possible coupling of the drill rods with each other may be achieved, when compared to conventional traditional jointing solu- tions.

With respect to this solution there has been found to be further developement possibilities as well particu- larly for the part of the coupling means, that may cause a certain risk for the operating reliability of the drilling apparatus, when being carried out merely mechanically. On the other hand there has not been success in carrying out advantageously enough in practice the coupling means operating by pressurized medium because of certain problems, one of the reasons for which is the fact, that movement of the mechanical

coupling parts belonging to the coupling means re- quires a displacement space arrangements so, that movement of the actuator in question could be enabled by influence of a displacement volume flow, when the pressure rises. This may naturally be carried out by displacement volumes placed in each drill rod, but this has not been found profitable enough from the economical or technical point of view.

The arrangement according to this invention belonging to a drilling apparatus is aimed to achieve a decisive improvement in the problems described above and thus to raise essentially the prior art. To achieve this aim the arrangement according to the invention is primarily characterized by, that the coupling means are arranged to operate by means of hydraulic fluid in a way, that the flow openings leading hydraulic fluid between the hammering means and the hydraulic system of the drilling apparatus and being placed one after another in the longitudinal direction get open essen- tially simultaneously, by placing a displacement space enabling functioning of the coupling means to the drilling device.

The most important advantages of the arrangement according to the invention are the simplicity, re- liability and convenience of its construction and use, which matters are crucial conditions for both techni- cally advantageous and favourable working. The arran- gement according to the invention is very simple to use first of all thanks to that, that the coupling means start to operate automatically when hydraulic fluid is been fed to the hammering means, whereby no extra installation measures are required. As an advantageous embodiment the displacement space in question enabling movement of the moving parts belon- ging to the coupling means are formed of the accumula- tor assembly storing hydraulic fluid that is of a high

pressure accumulator and a low pressure accumulator belonging to the same, whereby the displacement flow occurring to which is arranged to take place by means of feed flow and return flow assemblies being arranged between the accumulator assembly and a frame part surrounding the same.

Advantageous embodiments of the arrangement according to the invention are presented in the dependent claims.

In the following description, the invention is illu- strated in detail with reference to the appended drawings, in which Fig. 1 shows a typical use of the arrangement accor- ding to the invention as a side view, Fig. 2 shows an advantageous arrangement according to the invention at the male end of a loo- sened drilling device as a longitudinal section, Fig. 3 shows an advantageous arrangement at the female end e.g. of a drill rod being loosened as a longitudinal section, Fig. 4 shows successive components of the drilling apparatus being connected to each other, when the coupling means are in a rest position, as a longitudinal section and Fig. 5 shows a corresponding view as shown in fig.

4, when the coupling means are in an opera- tional position.

The invention relates to an arrangement in a drilling apparatus, at the drilling end I of which there is a

drilling device 1, that includes at least drilling means 2 and hammering means 5 as well as preferably flushing means 10, to drill a hole by means of the drilling means 2, preferably assisted by flushing medium led to the flushing means 10 from the flushing medium system of the drilling apparatus and made functional by a transmission arrangement situated at the driving end II of the drilling apparatus. Drilling occurs by using a feeding motion along the longitu- dinal axis s of the drilling device 1 and a rotational motion w around the longitudinal axis s as well as hydraulic fluid being led to the hammering means 5 from the hydraulic system of the drilling apparatus to achieve a to-and-for or a like hammering motion t. The drilling device 1 has jointing means 3 for attachment of a drill rod 4 removably to the same for increasing the drilling depth of the drilling apparatus. The drill rod 4 comprises a casing structure 4a equipped with corresponding jointing means 3, at least partly inside of which there has been arranged a flow assem- bly 7 to lead hydraulic fluid and/or flushing medium.

In connection with the jointing means 3 there has been arranged coupling means 6 for connecting the flow assembly 7 of the drilling apparatus 1 or of the drill rod 4, to a corresponding flow assembly 7 existing in the drilling device 1 and/or in a second drill rod 4 and/or at the driving end II of the drilling appara- tus. The coupling means include locking means 6dl, 6d2, that while detaching/attaching the component being treated at the moment by influence of pressuri- zed medium, essentially self-powered close/open at least the flow openings transmitting hydraulic fluid.

The coupling means 6 are arranged to operate by means of hydraulic fluid in a way, that the flow openings leading hydraulic fluid between the hammering means 5 and the hydraulic system of the drilling apparatus and being placed one after another in the longitudinal direction s get open essentially simultaneously, by

placing a displacement space x for hydraulic fluid enabling functioning of the coupling means 6 to the drilling device 1.

With reference to fig. 2 the drilling device 1 has a valve and control flow assembly controlling the flow of hydraulic fluid in the hammering means 5, to achieve the hammering motion t and a piston assembly 5b for carrying out the said hammering motion by influence of the above as well as an accumulator assembly Sc for storing hydraulic fluid, that has been arranged advantageously in connection with the hamme- ring means 5, e.g. according to fig. 2 centrically in the same longitudinal axis s between the piston assembly 5b and the valve and control flow assembly 5a. In this case the displacement space x is formed of the accumulator assembly Sc storing hydraulic fluid or in other words of a low pressure accumulator 5c2 and/or a high pressure accumulator 5cl belonging to the same.

With reference to fig. 1 the drilling device 1 has been arranged at least partly inside a protecting tube SP or a like. The hammering means 5 are arranged after the drilling means 2, such as one or several drilling bits or like at the drilling end I of the drilling device 1, whereby the flow assembly 7c for leading flushing medium is led preferably centrically through the piston assembly 5b and the accumulator assembly Sc placed after the above and, whereby a feed flow assem- bly 7a transmitting hydraulic fluid and a return flow assembly 7b of the same are led externally with respect to the piston assembly 5b. In this connection the displacement flow v of hydraulic fluid in the drilling device 1 is arranged to go to the accumulator assembly Sc by means of the feed flow and return flow assemblies 7a, 7b being arranged between the accumula- tor assembly Sc and the frame part 5d surrounding the

same. This principle may be found particularly from fig. 2 according to which the displacement flow v under a residual pressure of the drilling device 1, that is lower than the preliminary feed pressure of the high pressure accumulator 5cl, is arranged to take place to the low pressure accumulator 5c2 and under a higher residual pressure of the same in addition to the low pressure accumulator 5c2 to the high pressure accumulator 5cl, also.

Furthermore with reference particularly to figs 3 and 4, inside the casing structure 4a of each drill rod 4 there has been arranged correspondingly a feed flow way 7a to lead hydraulic fluid to the hammering means 5 and a return flow way 7b for returning of the same from the hammering means 5 as well as advantageously a flushing flow way 7c for transmitting of flushing medium between the flushing means 10 and the driving end II of the drilling apparatus. At the first end of the drill rod 4 there has been arranged according to fig. 3 a first end part 4al, that is to be attached advantageously removably to the casing structure 4a.

The first organs 6a of the coupling means, such as a female coupler has been placed furthermore removably to the end part in question, e.g. inside an extension part 4al', that is attached e.g. by means of a thread joint. Correspondingly at the other end of the drill rod 4 or the drilling device 1 there has been arranged a second end part 4a2, that has the second organs 6b of the coupling means, such as a male coupler, that has an external threading for forming of the said jointing means 3, and into which the internal threa- ding of the extension part 4al' of the female end may be attached.

The locking means 6dl, 6d2 being placed at both ends of e.g. the drill rod 4, that close/open the flow openings transmitting hydraulic fluid include sleeves

or like, that slide essentially in the longitudinal direction s and that are kept closed preferably by spring power 6cl, 6c2. Furthermore particularly with reference to figs 3 and 4 the drilling apparatus has a pressure space xl, that is arranged at the end of each drill rod 4 between a fixed frame part 4b, that is placed at the end of the drill rod 4, and the corresponding locking means 6dl, that may be pressuri- zed from the feed flow conduit 7a by means of a perforation R of the frame part 4b.

Furthermore as an advantageous embodiment the drilling apparatus includes a flow-through opening x2 being arranged to a fixed frame part 4b, lb, that is placed at the other end of the drilling device 1 or the drill rod 4, to connect the feed flow assembly 7a for hyd- raulic fluid, that is placed inside the frame part, to the return flow assembly 7b surrounding the same during the unlocked position of the corresponding locking means 6d2. This appears particularly from figs 2 and 4 as well as from fig. 5 in such respect, that during an operational situation shown in fig. 5 the opening in question is naturally closed so, that a "short circuit" flow balancing the internal pressures of the component in question may not happen.

With reference to fig. 5 since the displacement flow v of hydraulic fluid to the displacement place x has taken place, the said pressure space xl, when being expanded, is arranged to connect the feed flow assem- blies 7a for hydraulic fluid, that exist centrically inside the fixed frame parts 4b, lb placed at the ends of two successive components, such as two drill rods 4 or a drill rod 4 and a drilling device 1, to each other to lead hydraulic fluid further to the hammering means 5.

It is obvious, that the invention is not limited to the embodiments presented or described above instead it can be modified to a great extent within the basic idea. For one thing it is thus possible to construct the drill rod so, that e.g. the second end of the same and the middle part are integrated, in which case the drill rod is mountable through one end of the same only. Accordingly it is possible to construct both the coupling means and the flow arrangements in most heterogeneous ways. In addition to that, the joints between parts belonging to the drill rod may be in certain connections formed of e.g. shrink or bayonet joints. Thus the presented constructions are only examples of certain advantageous embodiments, which is why the basic idea of the invention concerning gaskets and the like technical matters may be adapted in practice in most heterogeneous ways. Moreover it is possible to form the flow arrangement of the flushing means of two conduits, whereby feeding of flushing medium takes place through the first conduit and suction of flushing medium takes place through the second conduit e.g. through interiors of the drilling device and the drill rods.