Drilling needle, drilling resistance measuring device and its use for wood quality assessment

Description

[0001] The invention relates to a drilling needle according to the preamble of claim 1 and its use for examining the condition of wooden objects. Such a drilling needle is known from document DE 10 2009 013069 A1.

[0002] It is known from the state of the art to examine tree trunks and wooden poles – i.e. living and dead wooden objects – for possible defects such as rot or similar. In any case, a minimally invasive examination is desirable, as the examination should not cause any damage. Drilling resistance measuring devices are used for these examinations. One such drilling resistance measuring device is known, for example, from DE 10 2013 001 711 A1. In these drilling resistance measuring devices, thin drilling needles are used for the monitored drilling resistance measurement process. The drilling needle is rotated at high speed and advanced axially, with the power consumption of the needle drive providing a measure of the penetration or drilling resistance, so that a drilling resistance profile can be recorded over the axial feed path of the drilling needle.

[0003] It is known to guide these drilling needles centrally during the drilling process, i.e., to support them against movement perpendicular to the drilling direction. For example, DE 100 31 395 A1 discloses a special cup telescope that guides the drilling needle into openings in the cup bases and can be retracted by the smaller cups moving into the next larger one. The drilling needle, which usually consists of a long shaft with a drilling needle head at the end, which has a drill point or cutting edge, is not described in detail.

[0004] A device for testing wood is also known from DE 41 22 494 B4. This device also features cylindrical telescopic sleeves in which the drilling needle is centrally guided. The head of the drilling needle shown is flattened with a widened drill tip, so that the rotational diameter of the drilling needle head is larger than the shaft diameter.

[0005] A needle that also has a wider head than shaft can also be seen in DE 44 38 383 C2: The needle shaft merges into a wide cutting edge with a pointed spike.

[0006] The needle head of the drilling needle from DE 10 2009 013 069 A1 is intended to ensure a uniform rotation of the needle and move the chipped wood material toward the needle shaft. To this end, the needle head also has a wide cutting edge at the end of a flattened wedge section, whose rotational diameter is larger than the shaft diameter, with the cutting edge running at a right angle to the rotational axis of the drilling needle. The angle spanned by the wedge section with a plane defined by the rotational axis and the edge is smaller than the angle spanned by the cutting surfaces of the cutting edge with the plane.

[0007] The well-known drilling needles are particularly suitable for a penetration angle that is horizontal and perpendicular to the object's axis. However, since rot in wooden masts, whose bases are in the ground, usually occurs approximately 10 cm below ground level, drilling at an angle of 15° to 45° to ground level is essential for mast inspection in order to reach rotting areas with the drilling needle without excavating the mast base. Ground level refers to a virtual average plane of the ground surface in the area where the wooden object stands. Conventional drilling needles tend to drift at penetration angles deviating from 90° to the object's axis, whereby the needle deviates from the intended axial feed direction, resulting in a channel that is not a straight line and may even miss the rotting area.

[0008] Therefore, there is a need to improve a drilling needle so that the insertion of the drilling needle into the object is carried out reliably even at an angle deviating from 90° to the object axis, in order to be able to examine object sections below the earth's level.

[0009] This object is achieved by a drilling needle having the features of claim 1 and by a drilling resistance measuring device having the features of claim 9.

[0010] The features of independent claim 10 disclose a use of the drilling needle or the drilling resistance measuring device for examining the quality of wood.

[0011] Further developments of the drilling needle are set out in the subclaims.

[0012] A first embodiment of the drilling needle according to the invention relates to a drilling needle with a drilling needle head having, at one end of a drilling needle shaft, a flattened wedge section with two diametrical wedge surfaces and a cutting section with two cutting surfaces, each of which adjoins one of the wedge surfaces and borders one another at a head edge that runs at a right angle to a rotational axis A of the drilling needle shaft. Furthermore, the wedge section has two diametrical flank segments that adjoin the wedge surfaces laterally and are rounded. According to the invention, the drilling needle head has a relief surface laterally adjacent to each of the two cutting surfaces, the design of which is coordinated with a rotational direction of the drilling needle.Thus, each of the two relief grinding surfaces forms, with one of the cutting surfaces, a leading cutting edge in relation to the direction of rotation, which extends from a head corner on the head edge to a cutting edge corner on the wedge surface. Correspondingly, each of the two relief grinding surfaces forms, with the other of the cutting surfaces, a trailing secondary edge in relation to the direction of rotation, which extends from the respective head corner on the head edge to a secondary edge corner on the wedge surface. A relief grinding angle α, which is spanned by a virtual straight line running through the cutting edge corner and the secondary edge corner with a plane extending through the rotation axis A perpendicular to the head edge, lies in a range of 6° to 10°. The trailing secondary edge is therefore shorter than the leading cutting edge.Therefore, the relief grinding surface has the shape of an irregular quadrilateral with one side rounded due to the rounded flank segment, where the four corners are the head corner, cutting edge corner, minor edge corner and another corner adjacent to the minor edge corner at the edge between the wedge surface and the flank segment.

[0013] According to a further embodiment of the drilling needle according to the invention, the clearance angle α can be 8°.

[0014] When using the drilling needle according to the invention with the specific drilling needle head geometry, drifting or non-straightening of the drilling needle during penetration, especially at a penetration angle deviating from 90° to the object axis, is minimized, since the cutting edge with the undercut relief surface prevents the drilling needle from first touching the annual rings with its head edge when penetrating at an angle deviating from 90° to the object axis. Thus, the drilling needle according to the invention enables reliable straight drilling, especially at an angle of 15° to 45° to the earth's surface.

[0015] According to a further embodiment of the drilling needle according to the invention, a cutting angle γ which the cutting edge spans with respect to the axis of rotation or with respect to a plane which runs perpendicular to the head edge through the axis of rotation can be in a range of 25° to 35°, preferably it is 30°.

[0016] Further embodiments of the drilling needle according to the invention can provide that the head edge has a width which provides a first rotational diameter which is wider than a diameter of the drilling needle shank, so that the chips can be displaced in the direction of the shank. In this case, the drilling needle head can preferably additionally have a second rotational diameter in a transition region of the wedge section with the cutting section, i.e. in the region of the rounded side of the relief surface on the flank segment, which is larger than the first rotational diameter, since the relief surface ensures chip removal. Alternatively or additionally, for uniform rotation of the drilling needle, an angle δ between the two wedge surfaces can be smaller than a head edge angle β between the two cutting surfaces.

[0017] The head edge angle β can be in a range from 85° to 95° and preferably 90°, while the angle δ between the two wedge surfaces can be in a range from 10° to 20° and can be, for example, 15°.

[0018] According to a further embodiment of a drilling needle according to the invention, it can be provided that the drilling needle head or the entire drilling needle is made of a steel which can be surface-hardened or through-hardened, wherein at least the drilling needle head, preferably the entire drilling needle, has a surface coating.

[0019] According to a further embodiment of a drilling needle according to the invention, a suitable surface coating can be formed by hard chrome plating. Alternatively, the coating can comprise nickel or polytetrafluoroethylene. The coating can advantageously have a layer thickness in the range of 8 to 12 µm. Alternatively, the drilling needle, at least its cutting end, can also be hardened by nitriding.

[0020] According to an exemplary embodiment of a drilling needle according to the invention, the width of the head edge can be in a range from 2.00 to 2.50 mm and is preferably 2.20 mm. The drilling needle head has a maximum width in a transition region of the wedge section with the cutting section in the region of the rounding of the relief surface between the cutting edge corner and the secondary edge corner, wherein this maximum width of the drilling needle head can be in a range from 2.25 to 3.00 mm and is preferably 2.75 mm. The height of the cutting section belonging to this exemplary embodiment, which is defined by the axial distance of the head edge to the wedge section edge, which extends between the cutting surface and the wedge surface from the cutting edge corner to the secondary edge corner, can be in a range from 0.30 to 0.40 mm and is preferably 0.35 mm.

[0021] In general, all wooden materials can be worked with the same needle; for particularly hard woods, a drilling needle with a hardened cutting edge can be advantageous.

[0022] In a first embodiment, a drilling resistance measuring device according to the invention comprises a drilling needle and a handheld device having at least one drive device with a drill chuck in which the drilling needle is clamped, which is a drilling needle according to the invention. Further embodiments of the drilling resistance measuring device according to the invention relate to the fact that the handheld device can have a guide device for guided insertion of the drilling needle into a wooden object to be examined and / or a drilling resistance detection device.

[0023] An inventive use of a drilling resistance measuring device according to the invention with a drilling needle according to the invention for examining the condition of a wooden object such as a mast or tree trunk provides that when the drilling needle is inserted into the wooden object in an axial feed direction, which can be freely selected with respect to an object axis or a ground level, a rectilinear drilling channel is created in the axial feed direction. Preferably, the wooden object can have a section below the ground level, and the drilling channel can extend from a penetration point above the ground level into the section below the ground level, wherein a penetration angle ε between the axial feed direction and the ground level can be in a range of 15° to 45°.

[0024] When using a drilling needle according to the invention, it is thus possible in particular to examine sections of the wooden objects below ground level, which require a penetration angle of 15° to 45° when drilling above ground level, whereby, unlike with conventional drilling needles, a precise, straight-line drilling channel is created with the drilling needle according to the invention.

[0025] Further embodiments, as well as some of the advantages associated with these and other embodiments, will become clearer and more easily understood from the following detailed description with reference to the accompanying figures. Items or parts thereof that are substantially the same or similar may be provided with the same reference numerals. The figures are merely a schematic representation of one embodiment of the invention.

[0026] Showing: Fig.1 a perspective view of the drilling needle head of a drilling needle in an embodiment according to the invention, Fig. 2 a top view of the drill needle head Fig. 1 , Fig. 3 a first side view of the drilling needle Fig. 1 , Fig. 4 a second side view of the drilling needle Fig. 1 , Fig. 5 a schematic view of a wooden object to be examined with a drilling resistance measuring device according to the invention.

[0027] The Fig. 1 to 4 The example shown shows as a device according to the invention a drilling needle 10 with a specifically shaped drilling needle head 1, which is particularly suitable for drilling resistance measurements by means of a drilling resistance measuring device 12, as in Fig. 5indicated, is suitable for use in a wooden object O at a penetration angle ε deviating from 90° to the object axis H. The invention also relates to a drilling resistance measuring device 12 with a drilling needle 10 according to the invention and its use for examining the properties of wooden objects O.

[0028] The specific shape of the drilling needle head 1 of a drilling needle 10 according to the invention, as shown in Figures 1 to 4can be seen, is based on a flattened wedge section K with an adjoining cutting section S at one end of the cylindrical drilling needle shaft 2. The wedge section K is defined by two wedge surfaces 3 lying in opposite directions, which are supplemented laterally by two corresponding rounded flank segments 3.1. The cutting section S consists of two cutting surfaces 8 adjacent to a head edge 4, which are connected to the wedge surfaces 3 and each form a wedge section edge 9 with these. The head edge 4 runs at a right angle to an axis of rotation A of the drilling needle shaft 2 and allows the definition of a first reference plane E1, which is defined by the head edge 4 and the axis of rotation A. A second reference plane E2 runs perpendicular, i.e. at a right angle, to the head edge 4 and also through the axis of rotation A.

[0029] In the cutting section S, the drilling needle head 1 has a free grinding surface 7 adjacent to the two cutting surfaces 8, which - as can be seen particularly well in the plan view in Fig. 2as can be seen - with each of the cutting surfaces 8 forms a cutting edge 5 which leads in the direction of rotation r and extends from a head corner 4.1 on the head edge 4 to a cutting edge corner 5.1 on the wedge surface 3. With the other of the cutting surfaces 8, each free-grinding surface 7 forms a secondary edge 6 which trails in the direction of rotation r and extends from the head corner 4.1 on the head edge 4 to a secondary edge corner 6.1 on the wedge surface 3. Both the two cutting edges 5 and the two secondary edges 6 and the clearance surfaces 7 delimited thereby can be mapped into one another by rotation through 180° around the rotation axis A and are thus point-symmetrical in plan view with respect to the rotation axis. The free-grinding angle α, which is formed by the virtual straight line h which passes through the cutting edge corner 5.1 and the secondary edge corner 6.1, spanning the plane E2, which extends through the rotation axis A perpendicular to the head edge 4, is 8° in the example shown and can, according to the invention, be in a range from 6° to 10°. The trailing secondary edge 6 is therefore shorter than the leading cutting edge 5, so that the relief surface 7 has the shape of an irregular quadrilateral with a rounded side that corresponds to the edge of the rounded flank segment 3.1. In addition to the head corner 4.1, the cutting edge corner 5.1 and the secondary edge corner 6.1, the relief surface 7 has a further corner (not labeled) that is adjacent to the secondary edge corner 6.1 on the edge between the wedge surface 3 and the flank segment 3.1.

[0030] Fig. 4shows the cutting angle γ of a drilling needle 10 according to the invention in an exemplary embodiment. The cutting angle γ is defined between the cutting edge 5 and the rotation axis A or the plane E2 and is 30° in the example shown, but can deviate from this in a range of 25° to 35°. Furthermore, Fig. 4 It can be seen from the dotted lines that the head edge 4 provides a rotation diameter which is wider than a diameter of the drilling needle shaft 2, but smaller than the rotation diameter which the drilling needle head 1 has in the transition region of the wedge section K with the cutting section S, ie in the region of the rounded edge of the free-grinding surface 7 to the flank segment 3.1.

[0031] In the example shown by Fig. 1 to 4The head edge 4 has a width of 2.20 mm, while the maximum width of the drill needle head 1 in the area of the rounded edge of the relief surface 7 to the flank segment 3.1 at the transition area of the wedge section K with the cutting section S is 2.75 mm. The height of the cutting section S in the axial direction between the head edge 4 and the wedge section edge 9 is 0.35 mm here.

[0032] Deviating from these preferred dimensions, a drilling needle 10 according to the invention can have a width of the head edge 4 in a range of 2.00 to 2.50 mm, wherein the maximum width of the drilling needle head 1 in the region of the rounded edge of the relief surface 7 to the flank segment 3.1 can be in a range of 2.25 to 3.00 mm, provided that the width of the head edge 4 is smaller than the maximum width. The height of the cutting section S can be in a range of 0.30 to 0.40 mm.

[0033] In the Fig. 3The side view shown shows the angle δ between the two wedge surfaces 3 and the head edge angle β between the two cutting surfaces 8, wherein it can be seen that the angle δ between the two wedge surfaces 3, which here at 15° lies within the inventive range of 10° to 20°, is significantly smaller than the head edge angle β, which in the example shown is 90°, but according to the invention can basically lie in a range of 85° to 95°.

[0034] According to a preferred embodiment, the drilling needle 10 can be made of a steel and have a hard chrome plating as a surface coating with a layer thickness in a range of 8 to 12 µm.

[0035] In Fig. 5are indicated a drilling resistance measuring device 12 according to the invention and its use for examining the condition of a wooden object O. The drilling resistance measuring device 12 has a drilling needle 10 according to the invention, for example the one shown in Fig. 1 to 4 illustrated drilling needle 10, and a hand-held device 11, the details of which are not shown and labelled, but which has at least one drive device with a drill chuck in which the drilling needle 10 is clamped, and optionally a guide device for the guided insertion of the drilling needle 10 into the wooden object O to be examined and / or a drilling resistance detection device.

[0036] This drilling resistance measuring device 12, which has a drilling needle 10 according to the invention, can be used to examine the condition of a wooden object O. When the drilling needle 10 is inserted into the wooden object O in an axial feed direction e, which can be selected as desired with respect to an object axis H or a ground plane G, a rectilinear drilling channel is created in the axial feed direction e, in that drifting of the drilling needle 10 is prevented by the specific design of the drilling needle head 1. Preferably, the wooden object O can have a section below the ground plane G, which is to be examined with the drilling resistance measuring device 12. For this purpose, the drilling channel can extend from a penetration point above the ground plane G into the section below the ground plane G, in that a penetration angle ε between the axial feed direction e and the ground plane G can be in a range of 15° to 45°.The penetration angle ε to reach an area of the object O to be inspected below the earth's level G depends not only on the height of the penetration point into the object O above the earth's level G, but also on the diameter of the object O to be inspected. LIST OF REFERENCE SYMBOLS

[0037] 1Drill needle head 2Shaft 3Wedge surface 3.1Flank segment 4Head edge 4.1Head corner 5Cutting edge 5.1Cutting edge corner 6Secondary edge 6.1Secondary edge corner 7Relief surface 8Cutting surface 9Wedge section edge 10Drill needle 11Handheld device 12Drilling resistance measuring device ARotation axis E1Plane through rotation axis and through head edge E2Plane through rotation axis and perpendicular to head edge GEarth HObject axis KFlattened wedge section OWood object SCutting section eFeed direction hVirtual straight line rRotation direction αRelief angle βHead edge angle γCutting angle δWedge surface angle εPenetration angle

Claims

1. A drilling needle (10) with a drilling needle head (1) that, at one end of a drilling needle shank (2), has a flattened wedge portion (K) with two wedge faces (3) and a cutter portion (S) with two cutting faces (8), which in each case adjoin one of the wedge faces (3) and adjoin one another at a top edge (4) that runs at a right angle to an axis of rotation (A) of the drilling needle shank (2), characterized in that the drilling needle head (1) has, on the side adjoining the two cutting faces (8), in each case a relief face (7) that - with in each case one of the cutting faces (8), forms a cutting edge (5) that leads with respect to a direction of rotation (r) and that extends from a top corner (4.1) at the top edge (4) to a cutting edge corner (5.1) at the wedge face (3), and - with the respective other one of the cutting faces (8), forms a secondary edge (6) that trails with respect to the direction of rotation (r), which extends from the top corner (4.1) at the top edge (4) to a secondary edge corner (6.1) on the wedge face (3), wherein a relief angle (α), which a virtual straight line (h) that runs through the cutting edge corner (5.1) and the secondary edge corner (6.1) spans with a plane (E2) that extends through the axis of rotation (A) perpendicular to the top edge (4), lies in a range from 6° to 10°.

2. The drilling needle (10) according to claim 1, characterized in that a cutting edge angle (γ), which the cutting edge (5) spans with respect to the axis of rotation (a), lies in a range from 25° to 35° and is preferably 30°.

3. The drilling needle (10) according to claim 1 or 2, characterized in that the top edge (4) provides a first diameter of rotation which is wider than a diameter of the drilling needle shank (2), wherein preferably the drilling needle head (1) in a transition region of the wedge portion (K) with the cutter portion (S) has a second rotation diameter that is larger than the first diameter of rotation; and / or an angle (δ) between the two wedge faces (3) is smaller than a top edge angle (β) between the two cutting faces (8).

4. The drilling needle (10) according to claim 3, characterized in that the top edge angle (β) lies in a range from 85° to 95° and is preferably 90°.

5. The drilling needle (10) according to at least any one of the claims 1 to 4, characterized in that the relief angle (α) is 8°.

6. The drilling needle (10) according to at least any one of the claims 1 to 5, characterized in that the drilling needle (10) is made of a steel and at least the drilling needle head (1) has a surface coating.

7. The drilling needle (10) according to claim 6, characterized in that the surface coating is a hard chrome plating, preferably with a layer thickness in a range of 8 to 12 µm.

8. The drilling needle (10) according to at least any one of the claims 1 to 7, characterized in that - a width of the top edge (4) lies in a range of 2.00 to 2.50 mm and is preferably 2.20 mm; and - a width of the drilling needle head (1) in a transition region of the wedge portion (K) with the cutter portion (S) lies in a range of 2.25 to 3.00 mm and is preferably 2.75 mm; and - a height of the cutter portion (S) lies in a range of 0.30 to 0.40 mm and is preferably 0.35 mm.

9. A drilling resistance measuring device (12) that has a drilling needle (10) and a hand-held device (11) that has a drive device with a drill chuck in which the drilling needle (10) is clamped, and optionally a guide device for guided insertion of the drilling needle (10) into a wooden object (O) to be examined and / or a drilling resistance detection device, characterized in that the drilling needle (10) is a drilling needle (10) according at least any one of the claims 1 to 8.

10. A use of a drilling resistance measuring device (12) according to claim 9 with a drilling needle (10) according at least one of the claims 1 to 8 for examining properties of a wooden object (O), wherein when the drilling needle (10) is inserted into the wooden object (O) in an axial feed direction (e), which can be selected as desired with respect to an object axis (H), a straight-line drilling channel is created in the axial feed direction (e).