EP3396105A1 - Expansion-shell bolt with lost drill bit - Google Patents

Abstract

The invention relates to a rock anchor (1) for anchoring in a borehole (100), comprising an anchor rod (2), a drill head (3) arranged on the anchor rod (2) for boring the borehole (100) into a mountain (101), wherein an expansion sleeve (4) is arranged on the anchor rod (2), wherein the expansion sleeve (4) is designed to anchor the rock bolt (1) in the drilled hole (100), and a method for anchoring such a rock bolt (1 ).

Description

The invention relates to a rock anchor for anchoring in a borehole, with an anchor rod and an arranged on the anchor rod drill head for drilling the borehole in a mountain range.

From the DE 10 2015 009 399 A1 Such a rock anchor is known. The drill head remains after drilling the borehole in the mountains, so that attachment of the rock anchor in the mountains can be made immediately after drilling the borehole. As a result, the use of a separate drill with a drill head can be saved, which would have to be removed after drilling the well into the mountains only from the well before the rock anchor can be introduced into the well. This results in considerable time savings, so that significantly more rock anchors can be anchored in the mountains in a much shorter time. At the rock anchor disclosed here with drill head a shell mixer is provided, is pressed through the holes for anchoring the rock anchor in the hole adhesive from a glue cartridge. A disadvantage of this rock anchor is that this is due to the use of adhesive only for certain mountain species. In addition, the holding force of such a rock anchor is limited and dependent on the properties of the adhesive, which may also vary over time. In addition, the use of this rock anchor is very expensive.

Against this background, it is an object of the invention to provide an improved rock anchor. In particular, a stable and safer Mountain anchor, which provides reliable and lasting hold in the borehole regardless of the type of mountain.

This object is achieved by the invention starting from a rock anchor of the type mentioned in that an arranged on the anchor rod expansion sleeve is provided, which is adapted to anchor the rock anchor in the drilled hole. The anchoring of the rock anchor by means of expansion sleeve offers the advantage of a reliable and secure anchoring of the rock anchor in the borehole. After drilling the borehole with the drill head arranged on the anchor rod, a reliable anchoring by spreading the expansion sleeve can be achieved by the expansion sleeve arranged on the anchor rod. The drill head on the anchor rod remains in the borehole, so that the expansion sleeve can be spread directly after the drilling process. As a result, considerable time savings in the anchoring of the rock anchor by means of expansion sleeve are possible. The use of glue or mortar is not required. Advantageous embodiments and modifications of the invention will become apparent from the dependent claims.

According to an advantageous embodiment of the invention, it is provided that the expansion sleeve has at least one expansion lever, which in spreading the expansion sleeve from a drilling position, in which the expansion lever rests parallel to the anchor rod, in a spread position, in which the expansion lever protrudes away from the anchor rod, displaced is. Preferably, the expansion sleeve has a plurality of evenly distributed around the sleeve circumference expansion lever, which center the anchor rod evenly when spreading the expansion sleeve in the borehole. The expansion levers ensure in this way for a secure hold in the borehole.

An advantageous embodiment is that an expansion element is provided, wherein the expansion element is adapted to cause a spreading of the expansion sleeve in the borehole. By operating the expansion element, the safe and reliable spreading of the expansion sleeve in the hole is possible.

A preferred embodiment provides that the expansion element is connected to a support element, wherein the support element is adapted to support the expansion element on the borehole wall and to secure against rotation relative to the borehole wall. The support of the expansion element in the borehole allows a spreading of the expansion sleeve by means of an anchor rod induced movement of the expansion element relative to the expansion sleeve without the expansion element moves with the anchor rod.

In a further preferred variant it is provided that the expansion element is screwed on a thread of the anchor rod along the anchor rod in a direction of screwing against the expansion sleeve, wherein the screwing of the expansion element against the expansion sleeve causes a spreading of the expansion sleeve. The screwing of the expansion element against the expansion sleeve provides a simple and secure way to cause the spreading of the expansion sleeve. When screwing the spreading element is guided in the thread on the anchor rod, so that it is moved by the screw rotation along the anchor rod in the direction of expansion sleeve. As a result, a high force is exerted by the expansion element on the expansion sleeve, which thus causes the spreading of the expansion sleeve and allows safe anchoring of the rock anchor in the mountains.

Particularly advantageous is the development that the support element is designed as a spiral spring having an at least partially larger diameter than a drill hole producible by the drill head in an unloaded state. Such a trained spiral spring offers the possibility to support the spreader simple but safe on the borehole wall. During the drilling process, the coil spring is stretched by the rotational movement of the anchor rod in the borehole, so that its diameter is reduced to the borehole diameter compared to the unloaded state. Upon reversal of the rotational motion on the anchor rod, the coil spring is compressed in the borehole so that the coil spring is effectively supported on the borehole wall. As a result, the expansion element can be easily screwed onto the thread of the anchor rod in the direction of the expansion sleeve, without the spreader rotates during the Schraubdrehbewegung. The use of the spiral spring has the advantage that the support element easily Deviations of the borehole diameter can adjust. For this purpose, the diameter of the coil spring in the unloaded state is at least partially greater than the drill hole producible by the drill hole in the mountains, ie larger than the diameter of the drill head itself.

Further advantageous embodiment is that the coil spring surrounds the anchor rod and that the coil spring is connected to the drill head end with the spreader, while the other end of the coil spring against the spring force of the coil spring is displaced. The connection of the borehole end of the coil spring to the expansion element facilitates the stretching of the coil spring during the drilling process. While the free end of the coil spring can be effectively supported on the borehole wall. About this second end of the coil spring, the compression of the coil spring can be effectively initiated upon reversal of the rotational movement of the anchor rod, so that the support of the Abstütztelementes is reinforced at the borehole wall by the compression.

In a further preferred variant, it is provided that the spiral spring has a diameter which increases from the drill head end of the spiral spring. With an increasing from the drill head end of the coil spring diameter can be particularly effectively cause a compression of the coil spring upon reversal of the rotational movement for spreading the expansion sleeve, so that the coil spring allows reliable support of the expansion element against the borehole wall.

A preferred embodiment provides that the expansion element is secured in a direction opposite to the screw rotation direction by a positioning on the anchor rod against rotation, wherein the spreader is formed in the direction of screw rotation by rotation about the anchor rod of the positioning element detachably. Securing the expansion element by means of a positioning element in the direction of rotation opposite the direction of screw rotation allows the expansion element to maintain the intended position on the anchor rod during the drilling process. Turning the anchor rod in the direction of screwdriving then triggers this Spreading element from the positioning, so that the expansion element can initiate a spreading of the expansion sleeve.

In a further preferred variant it is provided that the drill head is designed such that it cuts in a preferred direction of rotation about the anchor rod into the mountains, wherein the drilling direction of rotation is opposite to the direction of screw rotation. Such a trained drill head offers the possibility that the expansion element is screwed onto the thread of the anchor rod in the screw direction against the expansion sleeve, wherein the screw can be initiated by reversing the rotational movement of the anchor rod after the drilling process. This provides an easy way to initiate the spreading of the expansion sleeve by a simple reversal of the rotational movement of the anchor rod and thus anchor the rock anchor safely in the mountains.

Further advantageous is the embodiment that the drill head has an idle in the direction of rotation opposite direction of rotation about the anchor rod. By such an idle (or freewheel) can be ensured that the drill head on reversal of the rotational movement of the anchor rod for spreading the expansion sleeve does not rotate further in the borehole and mountains breaks out, which could hinder the spreading of the expansion sleeve. Such an idle can be most easily formed by two elements that misjudged each other during rotational movement of the anchor rod in the direction of drilling rotation and in the opposite direction of rotation, so the Schraubdrehrichtung solve each other.

The invention furthermore relates to a method for anchoring a rock bolt described in more detail above and below, the method comprising the following steps: providing rock bolts and clamping rock bolts in a drill chuck of a drilling machine, drilling borehole into rock with drill head by rotating the anchor rod into a Bohrdrehrichtung and propulsion into the mountains, spreading of expansion sleeve in the borehole by reversing the direction of rotation of the anchor rod and unclamping rock anchor from drill chuck of the drill. The method has the advantage that the rock anchor on the spreading of the expansion quickly and safely in the Drilling hole drilled. After the previously performed drilling is completed, can be started immediately with the spreading of the expansion sleeve without the drill head must be removed from the well and without the drilling tool must be discontinued. As a result, the use of a separate drill with drill head can be saved, which would have to be removed after drilling the well into the mountains only from the well before the rock anchor can be introduced with the expansion sleeve in the hole. By saving this step considerable time savings are possible.

A preferred embodiment of the method provides that the anchored by spreading the expansion sleeve in the borehole rock anchor is additionally braced, i. that the rock anchor is put under tension. For this purpose, preferably arranged on the anchor rod retaining plate is supported on the mountains around the wellbore and screwed by means of a clamping nut on a projecting out of the borehole threaded portion of the anchor rod. Alternatively, the retaining plate can be firmly connected to the anchor rod via the clamping nut.

Figur 1:

erfindungsgemäßer Gebirgsanker mit Spreizhülse in Spreizstellung,

Figur 2:

erfindungsgemäße Ankerstange,

Figur 3:

erfindungsgemäße Ankerstange mit Halteplatte,

Figur 4:

erfindungsgemäßer Gebirgsanker bei Montage,

Figur 5:

7 erfindungsgemäßer Gebirgsanker bei Montage,

Figur 6:

erfindungsgemäßer Gebirgsanker,

Figur 7:

erfindungsgemäßer Gebirgsanker bei Bohrvorgang,

Figur 8:

erfindungsgemäßer Gebirgsanker bei Setzstopp.

Further features, details and advantages of the invention will become apparent from the following description and from the drawings. Embodiments of the invention are shown purely schematically in the following drawings and will be described in more detail below. Corresponding objects or elements are provided in all figures with the same reference numerals. Show it:

FIG. 1:

Rock anchor according to the invention with expansion sleeve in spread position,

FIG. 2:

anchor rod according to the invention,

FIG. 3:

Anchor rod according to the invention with retaining plate,

FIG. 4:

Rock anchor according to the invention during assembly,

FIG. 5:

7 mountain anchor according to the invention during assembly,

FIG. 6:

rock anchor according to the invention,

FIG. 7:

Rock anchor according to the invention during drilling,

FIG. 8:

According to the invention rock anchor at Setzstopp.

In the figures, designated by the reference numeral 1, an inventive rock anchor 1 is shown. The representation according to FIG. 1 shows the rock anchor 1 anchored in the mountains 101, since the expansion lever 5 of the expansion sleeve 4 in spread B and fix the anchor rod 2 in the hole 100. The rock anchor 1 is used for anchoring in the wellbore 100 and for attachment of mountain layers together. For this purpose, the anchor rod 2 bridges the layers pierced with the drill head 3. A holding plate 10, which covers the borehole 100 from the outside and the expansion sleeve 4 ensure a cohesion of the bridged by the anchor rod 2 mountain layers. In this way, as is known, ceilings in cavities can be secured in mining and tunneling. The cohesion of the mountain layers can be further enhanced by the fact that the rock anchor 1 is braced in the wellbore 100. For drilling the borehole 100 in the mountains 101, the drill head 3 is arranged at the tip of the anchor rod 2. Below the drill head 3, the expansion sleeve 4 arranged on the anchor rod 2 can be seen, which anchors the rock anchor 1 in the borehole 100 bored through the drill head 3. In the expansion position B of the expansion lever 5 shown, these projects away from the anchor rod 2, exert pressure on the borehole wall 102 and penetrate into the mountain 100 in order to ensure a secure hold of the rock anchor 1.

The FIG. 2 shows an anchor rod 2 of the rock anchor 1. The anchor rod 2 has in the upper part, starting from the top of the anchor rod 2, an external thread 8. At the lower end of the anchor rod 2, a fixedly arranged on the anchor rod 2 clamping nut 11 is shown, with which the Rock anchor 1 can be fixed for example in the drill chuck of a drill.

FIG. 3 also shows the anchor rod 2 of the rock anchor 1. At the lower end of the anchor rod 2, a circular retaining plate 10 is arranged, which surrounds the anchor rod 2 by a hole formed in the support plate 10. Below the retaining plate 10, a clamping nut 11 is provided, which is bolted to a threaded portion of the anchor rod 2, not shown. About the screwing of the clamping nut 11 to the anchor rod 2, the rock anchor 1 can be clamped to the support plate 10 in the wellbore 100.

The FIG. 4 shows the mounting of the rock anchor 1. On the anchor rod 2, a positioning element 9 is arranged, which secures a spreading element 6 in a rotational direction against rotation, wherein the expansion element 6 is detachably formed in the opposite direction of rotation about the anchor rod 2 of the positioning element 9. The expansion element 6 is screwed during assembly in Aufschraubdrehrichtung E along the anchor rod 2 on the thread 8 in the screwing F until it is secured by the positioning element 9 against further rotation in Aufschraubdrehrichtung E. With the expansion element 6 designed as a spiral spring support member 7 is connected. The support element 7 serves to support the expansion element 6 on the borehole wall 102 and to secure against rotation with respect to the borehole wall 102. In the unloaded state, the coil spring 7 has a diameter which is larger than the borehole 100 produced by the boring head 3. In this way, the spiral spring 7 can securely support the expansion element 6 against the borehole wall 102. The coil spring 7 is for this purpose at its drill head end 7a connected to the expansion element 6. From this connection point, the spiral spring 7 has an increasing diameter, which increases to the free end 7 b of the spiral spring 7.

Out FIG. 5 a further assembly step in the production of the rock anchor 1 shows. Here, the expansion sleeve 4 is mounted with its expansion lever 5 in the mounting direction G on the anchor rod 2. The expansion lever 5 of the expansion sleeve 4 are aligned in the mounted state in the drilling position A, that is, that the expansion lever 5 substantially parallel to the anchor rod 2 on the Spread sleeve 4 rest. As a result, the expansion sleeve 4 can be easily inserted into the borehole 100 during the drilling process.

The FIG. 6 shows a rock anchor 1 according to the invention in the fully assembled state. The arranged at the top of the anchor rod 2 drill head 3 has been screwed in the last assembly step on the thread 8 of the anchor rod 2 in Aufschraubdrehrichtung E until the drill head 3 in Aufschraubrichtung F, the expansion sleeve 4 contacted. In the exemplary embodiment, the drill head 3 has two drill head cutting edges 3a, 3b, which rotate about the armature rod 2 about its own axis in the direction of rotation D ( Fig. 7 ) into the mountains 101. In opposite to the direction of rotation D direction of rotation about the anchor rod 2, the drill head 3 has an idle, so that the Bohrkopfschneiden 3a, 3b do not intersect in this opposite direction of rotation in the mountains 101. In order to save time in the tension of the rock anchor 1 in the borehole 100, the holding plate 10 and the clamping nut 11 is already arranged on the anchor rod 2 for this purpose.

In FIG. 7 a rock anchor 1 according to the invention is shown during drilling of the borehole 100 into the mountains 101. The drill head 3 with the Bohrkopfschneiden 3a, 3b cuts through the rotation of the anchor rod 2 in the direction of rotation D and the propulsion H in the mountains 101. For the drilling operation of the rock anchor 1 is clamped in a not shown drill chuck of a drill, not shown. The rotation in the rotational direction of rotation D and the propulsion H stretches the coil spring 7 abutting the borehole wall 102 in the borehole 100 and cuts a type of borehole thread 103 into the borehole wall 102. This helps to support the expansion element 6 against the borehole wall 102 and against rotation to secure against the borehole wall 102 at the later anchorage. The expansion lever 5 of the expansion sleeve 4 are located during the drilling operation in a Bohrstellung A, in which the expansion lever 5 rest parallel to the anchor rod 2 on the expansion sleeve 4 and so do not hinder the drilling process by means of the drill head 3.

FIG. 8 shows the rock anchor 1 at the set stop. Here, the holding plate 10 already contacted the mountains 101 and the drill head 3 has cut into the formation of the borehole 100 in the mountains 101. This as a coil spring 7 trained support member 7 is now stretched and is due to the larger diameter in the relaxed state at the narrower borehole wall 102 under tension. As a result, the support element 7 supports the expansion element 6 against the borehole wall 102 and secures it against rotation with respect to the borehole wall 102. In this situation, the expansion levers 5 of the expansion sleeve 4 are still in the drilling position A parallel to the anchor rod 2 on the expansion sleeve 4. The drill head 3 has fulfilled its task after drilling the borehole 100 and merely serves as a bearing of the anchor rod 2 in the bore 100.

After the setting stop, the spreading of the expansion sleeve 4 begins to anchor the rock anchor 1. For further explanation of this process is again on the FIG. 1 directed. When spreading the expansion sleeve 4, the expansion lever 5 of the expansion sleeve 4 are displaced so that they protrude away from the anchor rod 2, as in FIG. 1 is shown. In the spread position B shown here, the expansion lever 5 is supported on the borehole wall 102 and pressed against the mountains 101 to anchor the rock anchor 1 in the mountains. The spreading of the expansion sleeve 4 in the borehole 100 is effected by the expansion element 6. The expansion element 6 is connected to the trained as a spiral spring 7 supporting element 7, which secures the expansion element 6 against rotation relative to the borehole wall 102. The arranged on the thread 8 of the anchor rod 2 expansion element 6 can be screwed against the expansion sleeve 4 by rotation of the anchor rod 2 in the direction of screw rotation C, ie against the rotational direction of rotation D. The screwing of the expansion element 6 against the expansion sleeve 4 causes a spreading of the expansion sleeve 4, so a displacement of the expansion lever 5 in spread B. B. The expansion element 6 is designed as a cone and exerts on the expansion lever 5 from a leverage. The rotation of the anchor rod 2 in the screwing direction C causes the coil spring 7 is compressed in the wellbore 100, so that the coil spring 7 is firmly supported on the borehole wall 102. This ensures that a torque is generated by the rotation of the anchor rod 2 in the direction of screw C, through which the expansion element 6 is screwed onto the thread 8 of the anchor rod 2 along the anchor rod 2 in the direction of expansion sleeve 4. The free end of the coil spring 7 and the then increasing diameter of the coil spring. 7 causes a reliable support of the coil spring 7 in the borehole 100 upon rotation of the anchor rod 2 in Schraubdrehrichtung C. By means of rotation in the direction of screw C and by securing the expansion element 6 against rotation relative to the borehole wall 102 by the support element 7, the expansion element 6 dissolves in the direction of screw rotation C. from the positioning element 9, where it was secured during the drilling process, and travels along the anchor rod 2 on the thread 8 in the direction of the expansion sleeve 4. During rotation of the anchor rod 2 in the screwing direction C, the drill head 3 does not turn further, as it is in the direction of Bohrdrehrichtung D opposite direction of rotation around the anchor rod 2 has an idle. After spreading the expansion sleeve 4 of the rock anchor 1 must be stretched only from the drill chuck of the machine. After spreading the expansion sleeve 4, the rock anchor 1 in the wellbore 100 can be braced. For this purpose, arranged at the lower end of the anchor rod 2 clamping nut 11 is screwed on a thread, not shown, in the direction of the expansion sleeve 4. As a result, the holding plate 10 sets firmly against the mountains 101 and ensures a corresponding bias in the anchor rod. 2

Bezuaszeichenliste

• 1 mountain anchor
• 2 anchor rod
• 3 drill head, 3a drill head cutting edge
• 4 expansion sleeve
• 5 spreading lever
• 6 expansion element
• 7 supporting element, 7a first spiral spring end, 7b second spiral spring end
• 8 threads
• 9 positioning element
• 10 holding plate
• 11 clamping nut
• 100 borehole
• 101 mountains
• 102 borehole wall
• 103 borehole threads
• A drilling position
• B spread position
• C screwing direction
• D drilling direction
• E screw-on direction of rotation
• F screw-on direction
• G mounting direction
• H propulsion

Claims (13)

Rock anchor (1) for anchoring in a borehole (100), with an anchor rod (2), a drill head (3) arranged on the anchor rod (2) for boring the borehole (100) into a mountain (101), characterized by an expansion sleeve (4) disposed on the anchor rod (2) and adapted to anchor the rock bolt (1) in the drilled borehole (100). Rock anchor (1) according to claim 1, characterized in that the expansion sleeve (4) has at least one expansion lever (5) which, upon spreading of the expansion sleeve (4) from a drilling position (A), in which the expansion lever (5) parallel to the anchor rod (2) abuts, in a spread position (B), in which the expansion lever (5) from the anchor rod (2) projects away, is displaced. Rock anchor (1) according to claim 1 or 2, characterized by an expansion element (6), wherein the expansion element (6) is adapted to cause a spreading of the expansion sleeve (3) in the borehole (100). Rock anchor (1) according to claim 3, characterized in that the expansion element (6) with a support element (7) is connected, wherein the support element (7) is adapted to support the expansion element (6) on the borehole wall (102) and against to secure a twist against the borehole wall (102). Rock anchor (1) according to claim 3 or 4, characterized in that the expansion element (6) on a thread (8) of the anchor rod (2) along the anchor rod (2) in a screwing direction (C) against the expansion sleeve (4) screwed is, wherein the screwing of the expansion element (6) against the expansion sleeve (4) causes a spreading of the expansion sleeve (4). Rock anchor (1) according to claim 4 or 5, characterized in that the support element (7) is designed as a spiral spring which in an unloaded state has an at least partially larger diameter than a drill hole (101) producible by the drill head (3). Rock anchor (1) according to claim 6, characterized in that the spiral spring (7) surrounds the anchor rod (2) and that the spiral spring (7) at the drill head end (7a) with the expansion element (6) is connected, while the other, free End (7 b) of the coil spring (7) against the spring force of the coil spring (7) is displaceable. Rock anchor (1) according to Claim 7, characterized in that the spiral spring (7) has a diameter which increases from the drill head end (7a) of the spiral spring (7). Rock anchor (1) according to one of claims 5 to 8, characterized in that the expansion element (6) is secured in a direction opposite to the screw rotation by a positioning element (9) on the anchor rod (2) against rotation, wherein the expansion element (6) in Screwing direction (C) by rotation about the anchor rod (2) of the positioning element (9) is detachably formed. Rock anchor (1) according to one of claims 5 to 9, characterized in that the drill head (3) is designed such that it cuts in a preferred direction of rotation (D) around the anchor rod (2) in the mountains (101), said Drilling direction (D) opposite to the screwing direction (C) is opposite. Rock anchor (1) according to claim 10, characterized in that the drill head (3) in the direction of rotation (D) opposite direction of rotation about the anchor rod (2) has an idle. Method for anchoring a rock anchor (1) according to one of the preceding claims comprising the following steps: Provision of rock anchors (1) and clamping of rock anchors (1) into a drill chuck of a drilling machine, - Drilling of borehole (100) in mountains (101) with drill head (3) by rotation of the anchor rod (2) in a Bohrdrehrichtung (D) and propulsion (H) in the mountains (101), - Spreading of expansion sleeve (3) in the borehole (100) by reversing the direction of rotation of the anchor rod (2) and, - Unclamping rock anchor (1) from drill chuck of the drill. The method of claim 12, wherein the anchored by spreading the expansion sleeve in the borehole rock anchor is braced in the borehole.

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