EP2339107B1 - Drilling device with telescopic auger, adapter piece and drilling method for drilling - Google Patents

Description

Background of the invention

The invention relates to a drill with telescopic auger, in particular for performing earth bores.

Such a drill is eg off DE 35 21 148 A1 known. It comprises a carrier device, a drill drive and a drill screw, wherein the drill drive is movably mounted on the carrier device and the auger is rotatable about the auger longitudinal axis by means of the auger drive and slidable along the auger longitudinal axis with respect to the auger drive. Such a drill with retractable auger allows the implementation of relatively deep holes even at low free working height above the drilling site.

US 2847188 describes a drilling drive with expanding and contracting auger which has a non-hydraulic rotary operation and for which the drill drive is not movably mounted on the support device. From this document, the features of claim 1 are known, with the exception of the features that the drill drive is hydraulic and that the hydraulic lifting drive is mounted within the shaft. DE 2731170 describes a carriage drilling machine having a telescoping drill drive.

Summary of the invention

The invention has for its object to provide a particularly compact drill drive auger combination, the spatial extent along and transverse to the drilling direction is particularly low.

According to the invention this object is achieved in that a drill is provided, which has elements for transmitting energy for the displacement of the auger along the Bohrschnecken longitudinal axis, wherein the elements for transmitting energy through the drill drive extend and wherein a hydraulic lifting drive within a shaft for Rotary transmission is arranged.

Such an arrangement of the elements within the auger drive saves space and protects the elements for energy transfer from mechanical damage when moving the auger drive. The provision of a hydraulic lift drive within a rotary transmission shaft allows work to be performed on well bores even at low working heights, e.g. must be worked under power lines suspended between masts.

According to the invention, the auger is rotatable by means of a drilling drive and displaceable by means of a hydraulic lifting drive. As a shaft for rotation transmission preferably serves a telescopic assembly having an inner tube and an outer tube, the telescopic members axially displaceable along the telescopic axis and with respect to the telescopic axis are rotatably connected to each other, wherein on the outer telescopic member, the screw lands of the auger are arranged. In a specific embodiment, the elements for transmitting energy are hydraulic hoses filled with hydraulic oil, which extend from a hydraulic pump to the hydraulic lifting drive or a hydraulic cylinder, which is arranged between two telescopic links of the telescopic arrangement and which are connected to one another via the hydraulic lifting drive or hydraulic cylinder are to move the telescopic members relative to each other.

Preferably, a support tube with a support tube longitudinal axis is provided around the auger, which is rotatable about the support tube longitudinal axis by means of the drill drive and displaceable along the support tube longitudinal axis. This support tube can be sunk and sliding without Bohrschecke at the drilling site. Thus, e.g. Samples are taken from the drilling area in the form of a core.

It is particularly advantageous if, in addition to the auger, a support tube surrounding the auger is provided with a longitudinal support axis which is rotatable about the support tube longitudinal axis by means of the auger drive and displaceable along the longitudinal axis of the support tube. The so-supported, or cased, drilling prevents loose material from falling from the inner wall of the bore into the bore. The borehole is thereby stabilized.

In an advantageous embodiment, the drilling rig has a drilling auger adapter piece which is rotatably and tensionably connected or connectable to the auger drive and to the upper end of the auger to permit rotation and / or displacement of the auger. In particular, this may be a support tube adapter piece, which is non-rotatably and tension-tightly connected to the drill drive and with the upper end of the support tube or can be connected to allow the rotation and / or displacement of the support tube. Preferably, the auger longitudinal axis and the support tube longitudinal axis are identical and the drill has a one-piece auger support tube adapter piece which is rotatably and tension-tightly connected or connectable to the auger drive and to the upper end of the auger to facilitate rotation and / or or to allow the displacement of the auger, and which with the drill drive and with the upper end of the support tube rotatably and tensile strength is connected or can be connected to allow the rotation and / or displacement of the support tube. Thus, the drill can be prepared in just a few steps for the aforementioned cased drilling.

The drill may be designed so that the drill drive, the support tube adapter piece and the upper end of the support tube have complementary formations, by means of which a positive connection between the drill drive and the adapter piece on the one hand and between the adapter piece and the support tube on the other hand can be produced.

The adapter piece of the drill can be an adapter flange, which has a central opening, by means of which it can be arranged around a rotary shaft of the hydraulic rotary drive and rotatably and tensile strength on a projecting from the rotary shaft complementary Drehwellenflansch, and which at its outer edge at least two formations by means of which it is rotatably connected with complementary formations of the upper end of the support tube and tensile strength. The adapter flange can be designed in several parts, in particular in two parts. This facilitates its mounting on the rotary shaft. Preferably, the at least two formations of the adapter flange and the complementary formations of the support tube along the circumferential direction of the adapter flange or along the circumferential direction of the support tube are evenly distributed thereby asymmetric or punctiform too strong force introduction into the adapter flange or in the support tube prevented.

Conveniently, in the drill, the support tube adapter piece with the drill drive rotatably and tensile strength connected and can be connected to the upper end of the support tube rotatably and tensile strength to allow rotation and / or displacement of the support tube. The adapter piece is preassembled on the drill drive or firmly / non-detachably connected to it. Only between support tube and adapter piece an assembly process is required. In particular, the support tube adapter piece can be arranged around a rotary shaft of the hydraulic rotary drive and have protruding from the rotating shaft at least two formations, by means of which it can be connected to complementary formations of the upper end of the support tube rotatably and tensile strength.

Conveniently, in the drill, the support device is movable and / or it has a boom, which may be a hinge arm, which is fastened with its base end to the support device and at the outer end of the drill drive is attached. This allows a demand-oriented optimal positioning of the drill drive with the auger mounted thereon and / or the support tube mounted thereon.

The adapter piece and the rotary shaft of the drill may be integrally formed, wherein the adapter piece and the rotary shaft are preferably welded together. Preferably, the adapter piece and the rotary shaft are made of steel.

Advantageously, a separate adapter piece for a drill of the type described above is provided, which is a support tube adapter piece, which can be connected to the drill drive and with the upper end of the support tube rotatably and tensile strength to the rotation and / or to allow the displacement of the support tube. Preferably, the drill drive, the support tube adapter piece and the upper end of the support tube have complementary formations, by means of which a positive connection between the drill drive and the adapter piece on the one hand and between the adapter piece and the support tube on the other hand can be produced. With such an adapter, a conventional drill can be retrofitted and better adapted for cased drilling.

The adapter piece can be an adapter flange, which has a central opening, by means of which it can be arranged around a rotary shaft of the hydraulic rotary drive and can be flanged on a complementary rotary shaft flange projecting from the rotary shaft in a torque-proof and tension-resistant manner, with the adapter flange at its outer edge being at least has two formations, by means of which it is rotatably connected with complementary formations of the upper end of the support tube and tensile strength. Preferably, the adapter flange is multi-part, in particular two parts, whereby its assembly is facilitated.

Preferably, the at least two formations of the adapter flange and the complementary formations of the support tube are arranged distributed uniformly along the circumferential direction of the adapter flange or along the circumferential direction of the support tube. As a result, asymmetric or punctiform excessive force is prevented in the adapter flange or in the support tube.

Conveniently, the adapter piece and the rotary shaft is made of steel.

Preferably, the adapter piece is a one-piece auger support tube adapter piece which can be connected to the drill drive and with the upper end of the auger rotationally and tensile strength to allow the rotation and / or displacement of the auger, with the drill drive and with the rotationally fixed and tensile strength can be connected to the upper end of the support tube to allow the rotation and / or displacement of the support tube.

Brief description of the drawings

• Fig. 1A, 1B, 1C und 1D eine schematische Darstellung eines erfindungsgemässen Teleskopbohrgeräts und verschiedene Schritte eines erfindungsgemässen Bohrverfahrens darstellen;
• Fig. 2A, 2B und 2C eine schematische Darstellung des erfindungsgemässen Teleskopbohrgeräts in verschiedenen Situationen während des erfindungsgemässen Bohrverfahrens darstellen;
• Fig, 3A und 3B einen wesentlichen Teil einer ersten Ausführung des erfindungsgemässen Teleskopbohrgeräts in einer ersten Stellung bzw. in einer zweiten Stellung darstellen;
• Fig. 4A und 4B einen wesentlichen Teil einer zweiten Ausführung des erfindungsgemässen Teleskopohrgeräts in einer ersten Stellung bzw. in einer zweiten Stellung darstellen;
• Fig. 5 eine schematische Ansicht der Unterseite eines erfindungsgemässen Adapterstücks für ein Stützrohr von Fig. 4A und 4B in der Blickrichtung entlang der Längsachse L1 von unten nach oben darstellt;
• Fig. 6 eine schematische Ansicht der Oberseite des Stützrohrs von Fig. 4A in der Blickrichtung entlang der Längsachse L1 von oben nach unten darstellt.

Further advantages, features and applications of the invention will become apparent from the following non-limiting description of an embodiment of the drill, the adapter piece and the method according to the invention with reference to the drawing, wherein:

• Figs. 1A, 1B, 1C and 1D represent a schematic representation of a telescopic drill according to the invention and various steps of a drilling method according to the invention;
• Figs. 2A, 2B and 2C a schematic representation of the inventive telescopic drill in different situations during the drilling process according to the invention represent;
• FIGS. 3A and 3B represent an essential part of a first embodiment of the inventive telescopic drill in a first position or in a second position;
• FIGS. 4A and 4B represent an essential part of a second embodiment of the telescopic ear device according to the invention in a first position or in a second position;
• Fig. 5 a schematic view of the underside of an inventive adapter piece for a support tube of FIGS. 4A and 4B in the viewing direction along the longitudinal axis L1 from bottom to top;
• Fig. 6 a schematic view of the top of the support tube of Fig. 4A in the viewing direction along the longitudinal axis L1 from top to bottom represents.

Detailed description of the preferred embodiment

In Figs. 1A, 1B, 1C and 1D a telescopic ear device according to the invention is shown in various snapshots of a drilling method according to the invention. The telescopic drill 1 includes a support device 2 (only schematically indicated), a boom 3, a drill drive 4 and a drill screw 8. The support device 2 may be movable. The boom 3 is movably mounted with its base end 3a on the support device. The drill drive 4 is movably mounted on the outer end 3b of the boom. The drill drive allows rotation of the auger 8 about its longitudinal axis. The necessary for the propulsion of the auger 8 in the soil 19 lifting movement takes place via a movement of the boom 3 with respect to the support device. 2 In order to ensure vertical alignment of the telescopic auger 8 during the entire drilling process, the support device 2 must be moved in the horizontal direction towards or away from the wellbore 20 with respect to the wellbore 20. These horizontal correction movements of the support device are complicated and error-prone, especially when, instead of or in addition to a pure horizontal method, the support device 2 is corrected by means of a multi-limbed cantilever (not shown). These correction movements by means of the support device 2 and, if necessary. By means of a multi-unit boom are unnecessary in the above-mentioned drill whose retractable and auger auger allows the implementation of relatively deep holes even at low free working height H above the drilling site. In Fig. 1A the drill 1 is shown above the soil 19 at the beginning of a first partial bore. In Fig. 1B the drill 1 is shown after completion of this first drill section, the depth of which substantially corresponds to the length of the auger 8. In Fig. 1C the drill 1 is shown with a mounted between the drill drive 4 and the auger 8 telescopic rod 13 at the beginning of a second partial bore. In Fig. 1D the drill 1 is shown after completion of this second drill section, the depth of which substantially corresponds to the length of the telescopic rod 13. The depth C of the overall bore corresponds to the sum of the length of the auger 8 and the length of the telescopic rod 13.

In Figs. 2A, 2B and 2C the telescopic drilling device according to the invention is shown in various situations during the drilling process according to the invention. Fig. 2A shows the drill 1 with a drill bit of length A before the start of drilling above the soil 19th Fig. 2B shows the drill 1 after completion of the first drilling section after the first part of the bore hole whose depth corresponds approximately to the length A of the auger 8, wherein the telescopic rod 13 is already provided for further drilling. Fig. 2C shows the drill 1 after completion of the second drilling section after the second part of the bore hole whose depth corresponds approximately to the length B of the telescopic rod 13. The depth C of the total well is about A + B.

In FIGS. 3A and 3B is an essential part of a first embodiment of the drilling device 1 according to the invention in a first position ( Fig. 3A ) or in one second position ( Fig. 3B ). Fig. 3A shows a portion of the boom 3 (see. Fig. 1A to 1D ), at the outer end 3b a hydraulic rotary drive 4 and a rotationally driven by this auger 8 are suspended. The hydraulic rotary drive 4 drives a rotary shaft 4a and a rotatably connected thereto Drehwellenflansch 4b. The auger 8 is extendable. For this purpose, a telescopic arrangement 7 is provided which has an inner telescopic tube or inner tube 7a and an outer telescopic tube or outer tube 7b. The inner tube 7a is rotatably connected to the rotary shaft 4a of the rotary drive 4. This rotationally fixed connection can be a welded connection, a positive connection (plug connection, screw connection, bayonet connection) or a frictional connection (slip clutch, etc.). In the embodiment shown, the inner tube 7a is flange-mounted on the rotary shaft 4a in a rotationally fixed manner via the rotary shaft flange 4b. The rotary shaft flange 4b thus assumes the function of a Bohrschnecken adapter piece 14. The outer tube 7b is axially displaceable on the inner tube 7a but rotatably mounted. On the outer tube 7b screw webs 8a are fixed, preferably welded, which together with the telescopic arrangement 7 form the extendable auger 8. Between the inner tube 7a and the outer tube 7b of the telescopic assembly, a hydraulic lifting drive 6 is arranged in the form of a hydraulic cylinder whose shell / housing is rigidly connected to the inner tube 7a and whose reciprocating piston is rigidly connected to the outer tube 7b, as in FIGS. 3A and 3B shown, or vice versa. At the lower end of the extendable and extendable auger 8 a drill bit 9 is attached.

The hydraulic lifting drive 6 is integrated via hydraulic lines 10a and 10b into a hydraulic circuit which contains a hydraulic pressure source (not shown). The hydraulic lines 10a and 10b have the function of elements 10 for transmitting energy for the displacement and the linear reciprocation of the telescopic auger 8 with respect to the hydraulic rotary drive 4 along the auger longitudinal axis L1. These energy transmission elements 10 pass through the drill drive 4, 6. Such an arrangement of the elements 10 within the auger drive saves space and protects these elements 10 from mechanical damage when moving the auger drive. An element for Energy supply 5 is provided. It includes a hydraulic control block 5a and a rotary union 5b fixed to the frame.

In Flg. 3A, the auger 8 is shown in its retracted position, ie at its shortest length. In Fig. 3B the auger 8 is shown in its extended position, ie with a greater length.

In FIGS. 4A and 4B is an essential part of a second embodiment of the drilling device 1 according to the invention in a first position ( Fig. 4A ) or in a second position ( Fig. 4B ). The difference between the first version ( FIGS. 3A and 3B ) and this second embodiment is that here an additional support tube 12 is attached by means of a support tube adapter piece 16 to the drill 1. Otherwise, this second embodiment also contains all In Flg. 3A and Fig. 3B shown elements of the first embodiment. The statements made with regard to the first embodiment also apply correspondingly to the second embodiment.

The support tube adapter piece 16 is a flange-like structure 16 which is mounted non-rotatably on the rotary shaft 4 a and / or on the rotary shaft flange 4 b of the hydraulic rotary drive 4. These non-rotatable connection can be a welded connection, a positive connection (plug connection, screw connection, bayonet connection) or a frictional connection (slip clutch, etc.). In the embodiment shown, the underside of the support tube adapter piece 16 at least two formations F1, F2, which corresponding complementary formations F1 ', F2' at the upper end (front end) 12a of the support tube 12 are assigned. These formations F1, F2 and F1 ', F2', which are only shown schematically here, permit a positive and / or non-positive releasable connection between the hydraulic rotary drive 4 and the support tube 12.

Instead of the rotationally fixed attachment of the support tube 12 to the rotary shaft 4a and / or on the Drehwellenflansch 4b, the support tube 12 can be mounted non-rotatably at the upper end of the outer tube 7b of the telescopic assembly 7. The support tube adapter piece 16 would then have its formations F1, F2 and (not shown) complementary formations on the upper end (front end) of the outer tube rotatably mounted, while the connection with the Support tube 12 and in the preceding paragraph or in a similar manner would take place.

Particularly advantageous is an adapter that combines the function of the aforementioned auger adapter 14 or support tube adapter piece 16 in a single adapter piece, By means of such (not shown) Bohrschnecken support tube adapter piece then the support tube 12 would also be on the rotary shaft 4a the drill drive 4 or at the upper end of the outer tube 7b of the telescopic assembly 7 rotatably attach. Also this auger support tube adapter piece would then have to be mounted rotatably over formations on Adaperstück and complementary formations on the rotary shaft 4a and at the upper end (front end) of the outer tube.

Depending on the type of adapter piece used, the support tube 12 can thus be driven into the ground 19 before, during or after drilling with the auger 8 to the borehole inner wall 21 (see Fig. 2C ) of the borehole 20 to stabilize and stabilize.

In Fig. 5 Is the underside of an inventive adapter piece 16 for a support tube of FIGS. 4A and 4B in the viewing direction along the longitudinal axis L1 from bottom to top. The adapter piece 16 is a flange-like structure with a central circular opening 16a. Along the outer edge 16b of the adapter piece 16 are eight formations F1, F2, ..., F8, which are, for example, cylindrical depressions, distributed along the circumferential direction at uniform angular intervals. The cross symbol in Fig. 5 should indicate the deepening of the respective formation.

In Fig. 6 is the top of the upper end 12 a of the support tube 12 of Fig. 4A in the viewing direction along the longitudinal axis L1 from top to bottom represents.

The upper end 12a of the support tube 12 is widened in a flange. Along the annular end face 12a of the support tube 12 are eight formations F1 ', F2', ..., F8 ', which are, for example, cylindrical elevations, distributed along the circumferential direction at equal angular intervals. The dot symbol in Fig. 6 should indicate the increase of the respective formation.

The described complementary formations on the adapter piece 16 and the support tube 12 provide a rotationally fixed connection between the support tube and the adapter piece. This non-rotatable connection is e.g. by means of screws (not shown), bolts or splints, etc. axially fixed or secured. The adapter piece 16 is arranged by similar complementary formations (not shown) on the Drehwellenflansch 4 b of the hydraulic rotary drive 4 and on the underside of the adapter piece 16 rotatably.

The adapter piece 16 may be designed to facilitate its assembly in two parts or more parts. Preferably, it consists of two equal halves along the dashed adapter half-line L3 of the Fig. 5 can be joined together. In order to minimize the risk of injury to persons or objects in the vicinity of the drilling point, the outer edge 16b of the adapter piece 16 preferably forms a smooth circular line without radial projections.

Benefits, benefits and solutions mentioned in this document are not to be construed as critical, required or essential features or components of any claim or claims.

As used herein, the terms "comprises,""comprising," or any variety thereof, are intended to refer to a non-exclusive listing of elements such that any process, product, composition, or device of the invention, including any of the foregoing or that includes a list of elements, not only includes these listed elements, but may also contain other elements that are described in this patent. The use of the term "consisting" or "consisting of" or "consisting essentially of" is not intended to limit the scope of the invention to the enumerated elements recited thereafter unless otherwise specified.

Further properties and modes of action of the invention are described in the claims listed in the appendix.

Claims (14)

1. A telescoping auger (1) for performing drilling or production of boreholes (20), in particular subsurface drilling, comprising a carrier device (2), an auger drive (4), and a drilling auger (8) having a drilling auger longitudinal axis (L1), wherein the auger drive (4) is movably mounted on the carrier device (2), and the drilling auger (8) is rotatable about the drilling auger longitudinal axis (L1) by means of the auger drive (4) and is displaceable with respect to the auger drive (4) along the drilling auger longitudinal axis (L1), wherein the auger drive (4) is hydraulic, and the auger has elements (10) for energy transfer for displacing the drilling auger (8) along the drilling auger longitudinal axis (L1), wherein the elements (10) for energy transfer extend through the auger drive (4); and a hydraulic lift drive (6) for rotary transmission within a shaft (7) at which the drilling auger (8) is fastened, mounted, and connected to the elements (10) .
2. The telescoping auger according to Claim 1, characterized in that the drilling auger (8) is displaceable by means of a hydraulic lift drive (6), and comprises a telescoping assembly (7) with an inner tube (7a) and an outer tube (7b) acting as a shaft (7) for rotary transmission, and whose telescoping members (7a, 7b) are axially displaceable relative to one another along the telescopic axis and connected to one another so as to be rotatably fixed with respect to the telescopic axis, wherein the screw flights (8a) of the drilling auger (8) are disposed on the outer telescoping member (7b).
3. The telescoping auger according to Claim 2, characterized in that the elements (10) for energy transfer are hydraulic hoses (10a, 10b), filled with hydraulic fluid, that extend from a hydraulic pump to the hydraulic lift drive (6), or to a hydraulic cylinder disposed between two telescoping members (7a, 7b) of the telescoping assembly, and that are connected to one another via the hydraulic lift drive (6) or hydraulic cylinder in order to displace the telescoping members (7a, 7b) relative to one another.
4. The telescoping auger according to one of Claims 1 to 3, characterized in that in addition to the drilling auger (8), a support tube (12) that has a support tube longitudinal axis (L2) and that encloses the drilling auger is provided, which, by means of the auger drive (4), is rotatable back and forth about the support tube longitudinal axis (L2) and displaceable back and forth along the support tube longitudinal axis (L2).
5. The telescoping auger according to Claim 4, characterized in that the telescoping auger has a drilling auger adapter piece (14) that is connected or can be connected to the auger drive (4) and to the upper end of the drilling auger (8) in a rotationally fixed and tension-resistant manner to allow the rotation and/or the displacement of the drilling auger (8).
6. The telescoping auger according to one of Claims 4 and 5, characterized in that the telescoping auger has a support tube adapter piece (16) that is connected or can be connected to the auger drive (4) and to the upper end (12a) of the support tube (12) in a rotationally fixed and tension-resistant manner to allow the rotation and/or the displacement of the support tube (12).
7. The telescoping auger according to Claim 6, characterized in that the drilling auger longitudinal axis (L1) and the support tube longitudinal axis (L2) are identical, and that the auger has a one-piece drilling auger support tube adapter piece (14, 16) that is connected or can be connected to the auger drive (4) and to the upper end of the drilling auger (8) in a rotationally fixed and tension-resistant manner to allow the rotation and/or the displacement of the drilling auger (8), and that is connected or can be connected to the auger drive (4) and to the upper end (12a) of the support tube (12) in a rotationally fixed and tension-resistant manner to allow the rotation and/or the displacement of the support tube (12).
8. The telescoping auger according to Claim 6 or 7, characterized in that the auger drive (4), the support tube adapter piece (16), and the upper end (12a) of the support tube (12) have complementary formations by means of which a form-fit connection between the auger drive (4) and the adapter piece (16) on the one hand and between the adapter piece (16) and the support tube (12) on the other hand can be established.
9. The telescoping auger according to Claim 8, characterized in that the adapter piece is an adapter flange (16) which has a central opening (16a) by means of which the adapter flange can be disposed around a rotary shaft (4a) of the hydraulic rotary drive (4) and can be flanged to a complementary rotary shaft flange (4b), protruding from the rotary shaft (4a), in a rotationally fixed and tension-resistant manner, and which on its outer edge (16b) has at least two formations (F1, F2) by means of which it is connectable to complementary formations (F1', F2') of the upper end (12a) of the support tube (12) in a rotationally fixed and tension-resistant manner.
10. The telescoping auger according to Claim 9, characterized in that the adapter flange (16) has a multi-part, in particular two-part, form.
11. The telescoping auger according to Claim 9 or 10, characterized in that the at least two formations (F1, F2) of the adapter flange (16) and the complementary formations (F1', F2') of the support tube (12) are uniformly distributed along the circumferential direction of the adapter flange (16) and/or along the circumferential direction of the support tube (12), respectively.
12. The telescoping auger according to Claim 6, characterized in that the support tube adapter piece (16) is connected to the auger drive (4) in a rotationally fixed and tension-resistant manner, and can be connected to the upper end (12a) of the support tube (12) in a rotationally fixed and tension-resistant manner to allow the rotation and/or the displacement of the support tube (12).
13. The telescoping auger according to Claim 12, characterized in that the support tube adapter piece (16) is disposed around a rotary shaft (4a) of the hydraulic rotary drive (4), and has at least two formations (F1, F2), protruding from the rotary shaft (4a), by means of which the support tube adapter piece is connectable to complementary formations (F1', F2') of the upper end (12a) of the support tube (12) in a rotationally fixed and tension-resistant manner.
14. The telescoping auger according to one of Claims 1 to 13, characterized in that the carrier device (2) is movable and/or has a boom (3), in particular an articulated boom, which at its base end (3a) is fastened to the carrier device (2), and which at its outer end (3b) is fastened to the auger drive (4).

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