Abstract
A rod section of a ground drilling rod configured at its end to form at least one plug connection and having at one end (a) a connecting plug with an outer contour; or (b) a connecting socket with an inner contour, the outer contour or the inner contour being essentially sinusoidal in cross section.
Claims
1. A rod section of a ground drilling rod, the rod section comprising an end that is configured to form at least one plug connection and wherein the end comprises (a) a connecting plug having an outer contour; or (b) a connecting socket having an inner contour; wherein the outer contour or the inner contour is essentially sinusoidal in cross section, wherein the outer contour and the inner contour have straight lines.
2. The rod section according to claim 1, wherein the inner contour comprises arc-shaped inwardly and outwardly curved sections, wherein the arc-shaped inwardly and outwardly curved sections have a radius, wherein the outer contour comprises arc-shaped outwardly curved sections having a radius and arc-shaped inwardly curved sections having a radius, wherein the radius of the arc-shaped inwardly and outwardly curved sections of the inner contour is larger than the radius of the arc-shaped outwardly curved sections of the outer contour and smaller than the radius of the inwardly curved sections of the outer contour.
3. The rod section according to claim 1, wherein the straight lines have an angle to a centerline (X-X) of the cross-section of the rod section that is the same for adjacent straight lines.
4. The rod section according to claim 1, wherein the outer contour or the inner contour extends over a length of 10 millimeters (mm) to 120 mm in longitudinal extension of the rod section.
5. The rod section according to one of claim 1, wherein the end of the rod section is a chamfered end.
6. The rod section according to claim 1, wherein the inner contour comprises arc-shaped outwardly curved sections.
7. The rod section according to claim 1, wherein the outer contour comprises arc-shaped outwardly curved sections.
8. The rod section according to claim 1, wherein the inner contour comprises arc-shaped inwardly curved sections.
9. The rod section according to claim 1, wherein the outer contour comprises arc-shaped inwardly curved sections.
10. A drive element for impact driving a ground drilling rod into the soil, wherein the drive element engages with a rod section and wherein the rod section comprises an end that is configured (a) as a connecting plug or (b) as a connecting socket; wherein the connecting plug has an outer contour in cross section or the connecting socket has an inner contour in cross section, wherein said outer contour cross section or said inner contour cross section are essentially sinusoidal, wherein the outer contour cross section and the inner contour cross section have straight lines.
11. A rod section system of a ground drilling device, the rod section system comprising two or more rod sections, wherein at least one of the rod sections has a connecting plug comprising an outer contour in cross section, and at least another one of the rod sections has a connecting socket comprising an inner contour in cross section, and wherein each one of the outer contour and the inner contour are essentially sinusoidal in cross section and each having straight lines, wherein an angle (β) of the straight line of the outer contour to a centerline (X-X) of the cross section is greater than an angle (α) of the straight line of the inner contour to the centerline (X-X) of the cross section.
12. A ground drilling device comprising the drive element according to claim 10.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1) The invention is clarified below with reference to the exemplary embodiment shown in the figures.
(2) The figures show:
(3) FIG. 1 a schematic view of a ground drilling device with a drill rod;
(4) FIG. 2 a schematic view of a section of a ground drilling rod, in particular a rod section in a sectional view from the side;
(5) FIG. 3 an (inner) rod section of a dual tube rod;
(6) FIG. 4 a cross section A-A through a connecting plug of the rod section according to FIG. 3;
(7) FIG. 5 a cross section B-B through a connecting socket of the rod section according to FIG. 3;
(8) FIG. 6 a cross section through a connected plug connection of a connecting socket and a connecting plug, not under torque; and
(9) FIG. 7 a cross section through a connected plug connection of a connecting socket and a connecting plug, under torque.
DETAILED DESCRIPTION
(10) FIG. 1 shows a schematic of a ground drilling device 1 for trenchless laying of lines such as water, wastewater, power, or data lines during pilot borehole creation. The ground drilling device 1 is equipped with a rotary drive 2 and a feed drive 3 to move a drilling head 4 or a reaming tool, which is not shown, forward or backward through the soil 5.
(11) The drilling head 4, which is designed asymmetrically for executing controlled drilling paths, is located at a front end of a drill string 7, which is composed of individual drill rod sections 6.
(12) FIG. 2 shows a drill rod section 6, or rod section, in the form of a dual tube rod section. The drill rod section 6 has an outer tube 8, or an (outer) rod section. The outer tube 8 has a conical external thread at one end and a conical internal thread at the other end, so that at the ends, two outer tubes 8 of a drill rod section 6 can be screwed together. Within the outer tube 8 of a drill rod section 6 or a dual tube rod section, an inner tube 9, or (inner) rod section, is mounted such that it is movable. The inner tube 9 is fixed to the outer tube 8, the inner tube 9 being fixed in the outer tube 8 by means of a threaded ring 10 screwed into the outer tube 8. The inner tube 9 is accepted by the threaded ring 10 such that it can move longitudinally. To secure the inner tube 9 against sliding out of the outer tube 8, a stop ring 11 is slid onto the inner tube 9. The stop ring 11 is secured against axial displacement by a retaining ring 12.
(13) FIG. 3 shows an inner tube 9 as removed from the system (i.e., without the outer tube 8 of the dual tube rod section 6). The inner tube 9 has a bore 13 for the passage of drilling fluid, through which data or other energy lines (not shown) can also be passed. In order to ensure axial play of the inner tube 9 in the outer tube 8, each inner tube 9 has a sliding surface 14, which ends with a groove 15 for the retaining ring 12. On the side of the sliding surface 14 opposite the groove 15, there is a stop edge 16 to limit the axial movement of the inner tube 9 relative to the outer tube 8. The connection of the inner tubes 9 is designed as a plug connection, wherein they slide onto one other when the outer tubes 8 are screwed together.
(14) FIG. 4 shows a section A-A through a connecting plug 17 of the inner tube 9 of FIG. 3. FIG. 4 shows the outer contour 30 of the connecting plug 17 in cross section. FIG. 5 shows the inner contour 31 of the connecting socket 18 in cross section.
(15) FIG. 5 shows a section B-B through a connecting socket 18 of an inner tube 9 according to FIG. 3. The outer and inner contours 30, 31 in the cross section of connecting plug 17 and connecting socket 18 are shown in FIGS. 6 and 7 as a section of two connected inner tubes 9. The connection thereby of two adjacent drill rod sections 6 occurs as follows: Outer tubes 8 and inner tubes 9 of a dual tube rod section 6 to be newly connected are rotated independently of each other by the rotary drive 2 (in this case a double rotary drive). Now this new dual tube rod section 6 is brought up to another dual tube rod section 6 located in front of it. The plug connection of the inner tubes 9 has a (insertion) chamfer 19, 20 on both the connecting plug 17 and on the connecting socket 18. As soon as the inner contour 31 of the connecting socket 18 of an inner tube 9 that has been set in rotation is more or less aligned with the outer contour 30 of a connecting plug 17 of an adjacent or front inner tube 9, the inner tube 9 that is in the rear or to be connected slips into the inner tube 9 in front of it, which now rotates with it. During continued screwing of the outer tubes 8, the connecting socket 18 slides further onto the connecting plug 17 until the screwing process of the outer tubes 8 is completed. To compensate for length tolerances in the inner tubes 9 and the outer tubes 8, the inner tubes 9 are axially movable in the threaded rings 10 via sliding surfaces 14.
(16) FIGS. 4 to 7 show in detail a possible embodiment of the outer contour 30 of the cross section of the connecting plug 17 or the inner contour 31 of the cross section of the connecting socket 18.
(17) FIG. 6 shows a section through the connected plug connection without torque load. The outer contour 30 of the connecting plug 17 and the inner contour 31 of the connecting socket 18 are composed of inwardly and outwardly curved sections 21, 22 and of inwardly and outwardly curved sections 21′, 22′. The outwardly curved sections 22′ of the inner contour 31 have a radius R1′ and the inwardly curved sections 21′ of the inner contour 31 have a radius R2′. The inwardly curved sections 22 of the outer contour 30 have a radius R1 and the outwardly curved sections 21 of the outer contour 30 have a radius R2. R1′=R2′; R2<R1′ and R1>R1′.
(18) Between an outwardly curved section 21 of the outer contour 30 and an adjacent inwardly curved section 22 of the outer contour 30, there is a section that is in the form of a straight line 23. The outer contour 30 has twice as many straight lines 23 as outwardly or inwardly curved sections 21, 22. Between an inwardly curved section 21′ of the inner contour 31 and an adjacent outwardly curved section 22′ of the inner contour 31, there is a section that is in the form of a straight line 24. The inner contour 31 has twice as many straight lines 24 as outwardly or inwardly curved sections 21′, 22′.
(19) In the no-torque condition, as shown in FIG. 6, connecting plug 17 and connecting socket 18 are more or less concentrically aligned, wherein there is a small amount of play between connecting plug 17 and connecting socket 18. The straight lines 23, 24 of the contours of connecting plug 17 and connecting socket 18 have different angles to the centerline X-X, or S1 (example shown). In addition to the centerline S1, the centerline S2 running perpendicular thereto is also illustrated.
(20) The straight lines 23 of the connecting plug 17 are executed at the angle β to the centerline X-X. The straight lines 24 of the connecting socket 18 are executed at the angle α to the centerline X-X. Angle β is greater than angle α. All straight lines of the respective contours have a similar or identical design with respect to the angle to a corresponding center axis, which symmetrically divides a wave crest or wave trough.
(21) When a torque is applied to the connecting socket 18 or to the connecting plug 17, as shown in FIG. 7, there is a relative rotation between the connecting socket 18 and the connecting plug 17 by the angle Y, wherein the angle Y is calculated by subtracting the angle α from the angle β: Y=β−α.
(22) In the position shown in FIG. 7, the surfaces of straight lines 23, 24 of the connecting plug 17 and connecting socket 18 make contact, the loaded surfaces being based on the direction of rotation. Thus, the surface pressure between connecting plug 17 and connecting socket 18 is kept very low so that axial displacement between connecting plug 17 and connecting socket 18 is easily possible even under high torque. Due to the long lengths of the dual tube rod sections 6 (e.g., 3 to 6 m) and the associated length tolerances of the outer tubes 8 and the inner tubes 9 of the dual tube rod section 6, relative axial displacement of the inner tubes 9 with respect to each other is required. The positions as well as the lengths of the connecting plug 17 and connecting socket 18 are therefore designed appropriately.
