- 1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant/s: Hilti Aktiengesellschaft Actual Inventor/s: Kohler Oliver Address for Service is: SHELSTON IP 60 Margaret Street Telephone No: (02) 9777 1111 SYDNEY NSW 2000 Facsimile No. (02) 9241 4666 CCN: 3710000352 Attorney Code: SW Invention Title: EXTRUSION DEVICE The following statement is a full description of this invention, including the best method of performing it known to me/us: File: 51488AUP00 -2 BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an extrusion device for forcing out a mass from a self-drilling chemical rock anchor for mine and tunnel constructions. 5 Description of the Prior Art Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. For the stabilization of walls of hollow spaces formed in a rock mass, for 10 example, the walls of tunnels, galleries and the like, rock anchors, extending perpendicular to the walls, are used to secure consecutive rock strata which form the walls. In many cases, the rock strata which are located in an immediate vicinity of the wall and the mechanical properties of which, in particular their loading capacity, are reduced as a result of the formation of the hollow space. Rock anchors secure this rock 15 strata to undamaged rock strata located elsewhere. To set a chemically anchored rock anchor in a rock mass having low to medium hardness, a borehole is formed with a drilling tool into which a to-be-set rock anchor is driven in and a hardenable mass is injected. Finally, an anchor rod is placed into the borehole. The anchor rod is provided with an outer thread on at least the free end region 20 of the anchor rod that extends from the borehole. After the hardenable mass reaches a certain firmness, the rock anchor is secured in the rock mass with a locking nut. Each of the above-mentioned operational steps requires a different tool that must be mounted and dismounted. This leads to an increased time period for setting of each rock anchor. Also, at the start of the safety works, there exists a certain danger for the 25 operator because the operator must typically perform these necessary operational steps in unsecured regions of the hollow space. German Publication DE 197 00 701 Al discloses a power drilling tool for setting a rock anchor and which is capable of performing several steps. The power drilling tool includes a housing, a motor, and motor-driven sleeves rotatably supported in the housing -3 with a possibility of an axial displacement therein. Each sleeve has a first end with an insert opening in which there is provided a receptacle for rotation-imparting means for a rotatably driving a drill or a rock anchor. Each sleeve also has a second end located opposite the first end and having an opening. The drilling tool further includes a feeding 5 nozzle through which rinsing water is delivered during the drilling. The sleeves are exchangeably received in the drilling tool receptacle. After a borehole has been drilled, the sleeve with a drill rod-rotation-imparting means is replaced with an anchor rod rotation imparting means, and the anchor rod is set into the borehole and is tightened. One drawback of the drilling tool of DE 197 00 701 Al is that the exchange of 10 sleeves is expensive, in particular at conditions existing underground. In addition, the free end of the anchor rod extending from the borehole forms a stop that limits the displacement of the drilling tool toward the wall of the borehole. Consequently, at least one separate tool must be used for tightening of the rock anchor. Also, because the portion of the anchor rod that projects from the borehole depends on the setting process, 15 the underground, and the design of the rock anchor, this projecting portion is not constant. In order to further reduce the number of process steps required to set a rock anchor, so-called self-drilling chemical rock anchors were developed. U.S. Patent No. 4,055,051 discloses a self-drilling chemical rock anchor with a tubular element having a 20 drilling head provided at one of its ends and rotation-transmitting means at its opposite end for rotatably driving the anchor. The tubular rock anchor has its interior partially filled with a hardenable mass. Exit openings for the hardenable mass are provided in the drilling head or in the setting direction end region of the tubular element. The self drilling chemical rock anchor is rotatably driven in the ground with a power drilling tool. 25 After reaching a desired borehole depth, the hardenable mass is pressed-out with a piston. As soon as the extruded mass reaches a satisfactory firmness, a locking nut is screwed over the free end for tightening the rock anchor until the rock anchor is locked in the ground. One drawback of the rock anchor of U.S. Patent No. 4,055,051 is that the free 30 end of the anchor rod that projects from the borehole forms a stop that limits the -4 displacement of the drilling tool in the direction of the wall of the borehole. Consequently, a separate tool must be used to tighten the rock anchor. It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. 5 An object of the present invention in at least one preferred form is to provide an extrusion device for setting a self-drilling chemical rock anchor with which setting and, in particular, tightening of a rock anchor which is to-be-anchored in a borehole, is simplified. SUMMARY OF THE INVENTION 10 According to the invention, there is provided an extrusion device for forcing out a mass from a self-drilling chemical rock anchor for mine and tunnel constructions, the extrusion device comprising: a housing; a motor-driven sleeve rotatably supported in the housing without a possibility of 15 an axial displacement therein, the sleeve having a first end with an insert opening in which there is provided a receptacle for rotation-imparting means of the rock anchor, a second end located opposite the first end and having a through-opening, and a receiving space for a free end of the rock anchor extending from the receptacle for the rock anchor rotation-imparting means in a direction toward the second end of the sleeve and having 20 an inner cross-section smaller than a cross-section of the receptacle for the rotation imparting means; and a feeding nozzle extending through the through-opening of the second end of the sleeve for feeding an extruding medium for forcing the mass out of the rock anchor, the feeding nozzle being spaced from an inner profile of the sleeve to provide free space for 25 the free end of the rock anchor. Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".
-5 Advantageously, the extrusion device according to at least one embodiment of the present invention substantially simplifies the setting process of a self-drilling chemical rock anchor. The rock anchor is drilled in, the mass is extruded, and the rock anchor is tightened with one device. Therefore, no retrofitting is necessary. A 5 satisfactory process path is provided in the extrusion device for tightening the rock anchor in the borehole by the arrangement of the feeding nozzle and shaping of the receiving space. The rock anchor projects from the borehole and is provided with an outer thread. The locking nut is displaced along the free end of the rock anchor and is rotatably driven during the entire tightening process. 10 During the drilling process, rinsing medium in form of rinsing water is fed to the rock anchor through the feeding nozzle or in its vicinity. Finally, for extruding the hardenable mass stored in the rock anchor, water under high pressure, for example, is fed to the rock anchor as an extrusion medium. Advantageously, the extrusion device according to at least one embodiment of the invention is characterized by simplified 15 design with few movable parts, which ensures a high process reliability even at the conditions existing underground. Advantageously, in addition to chemically anchorable anchors, mechanically anchorable anchors are easily set and tightened. The inner profile of the receptacle is advantageously formed such that both the rotation-imparting means for rotatably driving the anchor and the locking nut can be 20 received. In this way, all of the process steps for setting the rock anchor are carried out with one sleeve. The rotation-imparting means preferably has a sleeve-shaped section that is provided with a predetermined break point and that, at least regionwise, surrounds the free end of the rock anchor. In addition, the sleeve-shaped section of the rotation 25 imparting means has an open bottom section through which the feeding nozzle is extendable. As soon as the mortar mass, which has been forced out of the rock anchor, has reached a satisfactory firmness, the motor is actuated again, whereby the sleeve shaped section of the rotation-imparting means breaks in the area of the break point, and the portion of the rotation-imparting means that has the imparting profile is displaced 30 along the outer thread of the rock anchor in a direction toward the wall of the borehole for tightening the rock anchor, as a locking nut. Alternatively, the rotation-imparting -6 means for rotatably driving the rock anchor is formed as a locking screw that is temporarily secured in the free region, for example, by soldering or welding points. When the rock anchor has been tightened, the temporarily securing means are lifted off, for example, by mechanical forces and the rock anchor is tightened by the locking nut. 5 Preferably, the receiving space has a cross-section that is between two and four times greater than a cross-section of the feeding nozzle. Thereby, with reference to the sleeve axis, sufficient receiving space is provided in the radial direction for the free end of the rock anchor. Advantageously, in this embodiment, the free end of the rock anchor cannot contact or damage the feeding nozzle during tightening of the rock anchor and 10 displacement of the device in the direction of the borehole wall. Preferably, the receiving space has an axial extent along a sleeve axis that is between two and five times greater than a mean dimension of the sleeve inner cross section. This advantageously provides a sufficient travel path for the extrusion device for tightening of the rock anchor. 15 Preferably, the extrusion device comprises a shank for securing the extrusion device in a chuck of a rock drill, the shank being operatively connected with the sleeve. This advantageously ensures that the extrusion device can be mounted on any conventional drill. In a preferred embodiment, the shank is formed directly on the sleeve to advantageously provide a one-piece component. 20 According to a further advantageous embodiment of the present invention, the sleeve is provided on its outer sides with a drive profile that provides for driving the sleeve directly by the motor directly or indirectly, via a drive unit. The drive profile is formed, for example, by toothing, that cooperates with the motor for the transmission of a torque. 25 Preferably, the extrusion device comprises a multi-channel feeding unit for feeding of the cleansing water and/or the extruding medium to the rock anchor. During the drilling process, cleansing water is fed to the rock anchor. When the desired depth has been reached, the feeding of the cleansing water is interrupted, and the feeding unit delivers the extruding medium to the rock anchor. This results in the hardenable mass 30 that fills the rock anchor being forced out. In order to be able to perform this step, the -7 feeding of the corresponding medium should be changed only once, without readjusting of the extrusion device. The invention, both as to its construction and its mode of operation, together with additional advantages thereof, will be best understood from the following detailed 5 description of preferred embodiments, when read with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS: The drawings show: Fig. 1 a cross-sectional view of a first embodiment of an extrusion device 10 according to the present invention; Fig. 2 a cross-sectional view of the extrusion device shown in Fig. I during the drilling process of a connection anchor; Fig. 3 a cross-sectional view of the extrusion device shown in Fig. I after completion of the setting process of the connection anchor; and 15 Fig. 4 a cross-sectional view of a rock drill with an integrated extrusion device according to a second embodiment of the present invention. In the drawings, the same parts are shown with the same reference numerals. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An extrusion device 11 for extruding a mass 2 out of a self-drilling, chemical 20 rock anchor 1 for mine and tunnel constructions, which is shown in Figs. I through 3, includes a housing 12, a motor-driven sleeve 21 rotatably supported in the housing 12 without a possibility of axial displacement, and a feeding nozzle 31 through which a medium is fed to the rock anchor 1. The sleeve 21 has a first end 22 with an insert opening 23 that is provided with a receptacle 24 for the rotation-imparting means 3 of 25 the rock anchor 1. A second end 25 is located opposite the first end 22 and provided with a through-opening 26. The sleeve also has a sleeve axis 27.
-8 Between the first end 22 and the second end 25 of the sleeve 21, there is provided a space 28 for receiving a free end 4 of the rock anchor 1. The space 28 extends from the receptacle 24 for the rotation-imparting means 3 in a direction of the second end 25 of the sleeve 21. The space 28 has a smaller cross-section than the cross-section of the 5 receptacle 24 for the rotation-imparting means 3. The feeding nozzle 31 projects through the through-opening 26 of the sleeve 21 and into the receiving space 28. The feeding nozzle 31 is spaced from the inner surface 29 of the sleeve 21 to provide a free space for the free end 4 of the rock anchor 1. An extrusion medium, such as water under high pressure, is fed to the rock anchor I through the feeding nozzle 31 for extruding the 10 mass 2 from the anchor 1. The receiving space 28 has a cross-section that is 2.5 times greater than the cross section of the feeding nozzle 31. The receiving space 28 has an axial extent L along the sleeve axis 27 and which is three times greater than the average dimension of the inner profile of the sleeve 21. 15 The sleeve 21 has a shank 36 formed thereon for mounting the extrusion device 11 in a chuck of a power drill (not shown in Figs. 1-3). A setting process of the rock anchor with the extrusion device 11 is described below with reference to Figs. 2-3. The rotation-imparting means 3 of the rock anchor I includes a sleeve-shaped 20 section 6 that is provided with a predetermined break point 7 and circumferentially engages the free end 4 of the rock anchor 1. The sleeve shaped section 6 has an open bottom section 8 through which the feeding nozzle 31 projects into the rock anchor 1. During the drilling process (see Fig. 2), the free end 4 of the rock anchor 1, which projects through the insert opening 23 into the receiving space 28, is spaced, by a 25 distance A from the end of the receiving space 28 adjacent to the second end 25 of the sleeve 21. During the drilling process, cleansing water that forms the cleansing medium is fed through the cleansing water conduit 32 and channels 33 to the rock anchor 1. As soon as the necessary hole depth is reached, feeding of the cleansing water is temporarily interrupted. The cleansing water is then fed to the rock anchor I over a 30 separate conduit 34 through a feeding channel 35 under high pressure as an extruding -9 medium, whereby the hardenable mass 2, which is located in the rock anchor 1, is forced out. As soon as the mass 2 exits the hole mouth 10, the user recognizes that the clearance between the rock anchor I and the hole wall has been filled, and stops delivery of the extruding medium. 5 When the forced-out mass 2 reaches a satisfactory firmness, the motor is again actuated, whereby the sleeve section 6 of the rotation-imparting means 3 is broken in the region of the predetermined breaking point 7. The section of the rotation-imparting means 3 that remains in the receptacle 24 of the sleeve 21 is displaced along an outer thread 9 of the rock anchor 1 in the direction of the hole wall 5, analogous to a locking 10 nut for tightening the rock anchor. As shown in Fig. 3, the free end 4 of the rock anchor 1 can penetrate into the receiving space 28 until the bottom section 8 of the sleeve shaped section 6 abuts the end of the receiving space 28 adjacent to the second end 25 of the sleeve 21. The distance A between the free end 4 of the rock anchor I and the end of the receiving space 4 is selected so that it provides a necessary travel path of the 15 extrusion device 11 for tightening the rock anchor 1. In the embodiment shown in Fig. 4, the extrusion device 51, having a receiving space 58, is integrated in a rock drill 41. The extrusion device 51 also has a sleeve 56, similar to the sleeve 21 of the extrusion device 11 shown in Figs. 1-3. The sleeve 56 differs from the sleeve 21 in that the sleeve 56 is provided on its outer side 57 with a 20 drive profile 59 in form of toothing that cooperates with the toothing of a gear wheel 43 driven by a motor 42, whereby the sleeve 56 is set in rotation. On the housing 44 of the drill 41, there is provided a multi-channel feeding unit 61 that provides for feeding of both cleansing water and extruding medium for forcing the hardenable mass 47 out of the rock anchor 46. The setting process and the function of separate components of this 25 embodiment of the invention are substantially the same as those of the extrusion device 11 described with reference to Figs. 1-3. Though the present invention was shown and described with references to the preferred embodiments, such are merely illustrative of the present invention and are not to be construed as a limitation thereof and various modifications of the present invention 30 will be apparent to those skilled in the art. It is therefore not intended that the present invention be limited to the disclosed embodiments or details thereof, and the present -10 invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims.