The present invention relates to a sawblade having a plurality of wave-shaped teeth which are formed on a continuous base section of the sawblade, the teeth each having an associated tooth base with a tooth base upper face and having a hard metal blade arranged thereon. The invention also relates to a hole saw.
A sawblade having a plurality of wave-shaped teeth which are formed on a continuous base section of the sawblade, the teeth each having a hard metal blade, is known from the prior art. For example, EP 0 054 885 A2 describes a sawblade in the form of a band sawblade which is equipped with hard metal plates. This band sawblade is supposed to have a long service life and a high permissible step speed and be suitable for cutting very hard materials, such as metals or stones. For this purpose, the band sawblade is unset, and the hard metal plates are fastened to seat surfaces which are perpendicular or inclined only slightly forward relative to the sawblade longitudinal extension. The hard metal plates have a height between ⅓ to ⅘ of a relevant tooth height and protrude on both sides beyond the sawblade thickness with undercut clearance widened portions.
The invention relates to a sawblade having a plurality of wave-shaped teeth which are formed on a continuous base section of the sawblade, the teeth each having an associated tooth base with a tooth base upper face and having a hard metal blade arranged thereon. Each tooth base adjoins the hard metal blade arranged thereon in a flush manner on both sides along a longitudinal axis of the base section, and each hard metal blade and each tooth base upper face has two bevels and/or convexly rounded areas extending substantially along the longitudinal axis of the base section, the teeth being unset and/or set.
This results in comparatively smooth saw cuts combined with an increased cutting efficiency. In addition, a higher sawing speed is possible with improved service life of the sawblade. The hard metal blades end flush with the relevant tooth base of the tooth on both sides and are thus supported in a stable and particularly robust manner. Due to the complete support of the hard metal blades, a particularly long service life of the hard metal blades fastened to the teeth is obtained. The tooth base in turn preferably adjoins the base section of the sawblade in a flush manner. A tooth base upper face, formed by the relevant tooth base and the hard metal blade embedded in a flush manner in the upper side thereof, is planar and descends in a straight line from a tooth tip to the tooth back. In the context of the present description, the term “set” defines the bending, preferably in opposite directions, of directly successive teeth out of a central plane defined by the rectangular base section of the sawblade. All teeth of the sawblade preferably have the same height regardless of the presence of a set. The geometry of the teeth of the sawblade according to the invention preferably approximates the so-called K-shape in side view (cf., inter alia, Brockhaus, “Naturwissenschaften und Technik”; volume 4; page 224; 1989).
Preferably, the bevels of each hard metal blade have substantially the same width.
This results, inter alia, in reduced cutting forces and self-centering of the sawblade in the kerf in the material to be cut. The bevels increase the crack resistance and the impact resistance. In the context of the present description, the term “bevel” is understood to mean a planar or prismatic slant of a workpiece edge.
In one embodiment, the bevels of each tooth have a different width.
As a result, even more effective self-centering within the kerf is ensured.
Preferably, the convex rounded areas have substantially the same radius.
As a result, mechanical stresses in the region of the cut faces can be further reduced.
According to a technically favorable development, two directly successive teeth along the longitudinal axis are in each case set in opposite directions to one another.
Due to the clearance of the sawblade realized thereby, the cutting forces occurring in the sawing process can be reduced further.
Preferably, at least one tooth is unset, and the two teeth which directly follow said tooth along the longitudinal axis are set in opposite directions to one another, and this set sequence is repeated along the longitudinal axis over all the teeth of the sawblade.
This periodic set sequence results in a wider kerf.
In one development, it is provided that at least one tooth is unset, and two further teeth which directly follow said tooth along the longitudinal axis are set in opposite directions to one another at a first set angle, and two further teeth which directly follow the teeth set in opposite directions at the first set angle along the longitudinal axis are set in opposite directions to one another at a second set angle, and this set sequence is repeated along the longitudinal axis over all the teeth of the sawblade.
As a result, any tendency of the sawblade to jam in the workpiece can be reduced further. The width of the bevels, their bevel angle and/or the radii of the convex rounded areas can vary individually depending on the set angles.
The first set angle is preferably smaller than the second set angle.
As a result, the angles of the sets increase in the cutting direction.
The hard metal blades preferably form a tooth tip above a concave chip space, pointing in the cutting direction, of each tooth.
As a result, a high cutting or sawing performance is provided. A tooth back is substantially rectilinear.
Preferably, the hard metal blades are fixedly connected to the tooth base of the teeth, in particular joined thermally thereto.
This results in a particularly robust, easy to manufacture connection between the hard metal blades and the tooth base of the teeth bearing said blades.
Preferably, the base section of the sawblade is formed with a tempered steel, and the hard metal blades are preferably formed with a tungsten carbide-cobalt hard metal.
This ensures sufficient flexibility of the sawblade. Furthermore, an excellent cutting performance combined with a long service life of the sawblade is realizable.
The invention also relates to a hole saw. This hole saw is formed with a sawblade which is bent substantially into a ring and is preferably designed as described above.
As a result, a hole saw or a drill bit with a considerably improved cutting performance in relation to previously known solutions can be realized.
The invention is explained in more detail in the following description with reference to exemplary embodiments shown in the drawings, in which:
For the sake of simplicity, structurally substantially identical elements having the same or comparable function are provided with the same reference signs throughout the drawings and are only described in detail once.
The sawblade 100 having the base section 102 illustratively has a central plane M in which a longitudinal axis 120 runs. A preferred cutting direction 198 of the sawblade 100 is indicated by an arrow 198.
Each of the teeth Z1,2 preferably has an assigned, solid tooth base 140, 142 or a tooth shaft having a tooth base upper face 150, 152 and a hard metal blade 114, 116 arranged thereon. Illustratively, the hard metal blades 114, 116 each form a tooth tip 158, 160 above a chip space 154, 156, pointing in the cutting direction 198, of each tooth Z1,2. The tooth base upper faces 150, 152 and upper faces 170, 172 of the hard metal blades 114, 116 embedded in the relevant tooth base 140, 142 adjoin one another in a flush manner and in each case form a tooth upper face 180, 182 which is substantially flat except for the continuous bevels (cf. in particular
The hard metal blades 114, 116 are preferably fixedly connected to the relevant tooth base 140, 142 of the respectively assigned tooth Z1,2, in particular thermally fixedly joined thereto. The thermal joining between the tooth bases 140, 142 of the teeth Z1,2 and the hard metal blades 114, 116 can be made, for example, by brazing or welding. The base section 102 of the sawblade 100 is preferably formed with a (highly) tempered steel, and the hard metal blades 114, 116 can be realized, for example, with a tungsten carbide-cobalt hard metal.
Preferably, each tooth base 140, 142 of each tooth Z1,2 in each case adjoins the hard metal blade 114, 116 arranged thereon in a flush manner on both sides along the longitudinal axis 120 of the base section 102. Furthermore, each hard metal blade 114, 116 and each tooth base upper face 150, 152 of the teeth Z1,2 preferably have in each case two continuous planar bevels F1, . . . , 4 or so-called slants extending substantially along the longitudinal axis 120 of the base section 102, i.e. in this case extending approximately perpendicular to the drawing plane. The tooth upper faces 150, 152 of the teeth Z1,2 lie behind the hard metal blades 114, 116 or the upper faces 170, 172 thereof in relation to the drawing plane.
The teeth Z1,2 can either be set or unset, as shown in the drawings here. In the first embodiment of the sawblade 100 shown here, the bevels F1, . . . , 4 preferably each have approximately the same width, wherein, for the sake of better clarity, only the widths B1,2 of the bevels F1, 4 on the outside relative to the central plane M are indicated.
In contrast to the first embodiment of the sawblade 100 according to
In contrast to the first two embodiments of the sawblades 100, 200 of
The convexly rounded areas K1, . . . 4 formed on both sides on the hard metal blades 274, 276 and on the tooth bases 260, 262 or the tooth base upper faces 264, 266 of the teeth Z5,6 preferably run at least approximately parallel to the longitudinal axis 120. The hard metal blades 274, 276 preferably in turn each adjoin the respective tooth bases 260, 262 of the teeth Z5,6 in a flush manner on both sides.
The convexly rounded areas K1,K4 on the outside relative to the central plane M preferably have the same radii R1,2. The same applies to the radii of the inside convexly rounded areas K2,3 of the teeth Z5,6, which radii are not indicated for the sake of better clarity. Deviating from this, the radii R1, . . . , 4 of the convexly rounded areas K1, . . . , 4 can all be the same size or can optionally differ by tooth or individually by tooth.
In contrast to the embodiments of the sawblades described in
The bevels F9, . . . , 12 provided on both sides on the hard metal blades 324, 326 and on the tooth bases 310, 312 or the tooth base upper faces 314, 316 of the teeth Z7,8 preferably run approximately parallel to the longitudinal axis 120. The hard metal blades 324, 326 preferably in each case terminate flush with the respective tooth bases 310, 312 of the teeth Z7,8 on both sides, resulting in, among other things, their high mechanical robustness and durability.
In contrast to the embodiments described in
Owing to the design of the teeth Z9, . . . , 11 according to the invention, a sawing channel bottom 392 is preferably largely smooth and burr-free and thereby stress-free. As a result, inter alia, the crack formation tendency in the sawing channel S and thus within the workpiece W can be significantly reduced.
The sawblade 400 having the base section 402 has the central plane M with the longitudinal axis 120 lying therein. The sawblade 400 is guided in the cutting direction 198 through the workpiece to be cut, which is not shown here.
In contrast to the fifth embodiment of the sawblade 350 according to
The shape of the teeth Z12, . . . 16 and their relevant structural design correspond only by way of example to the teeth of the first embodiment of the sawblade 100 according to
The width B4 of the bevel F10 of the tooth Z7 of the sawblade 300 is preferably selected to be larger than the width B3 of the bevel F9 of the tooth Z7. In this case, the bevel angle γ4 of the bevel F10 is preferably not smaller than the bevel angle γ3 of the bevel F9. The dimensional ratios explained in the context of the description of
The six embodiments of the sawblades 100, 200, 250, 300, 350, 400 described above are preferably provided for use in power saws or hand saws of all types. With the aid of the sawblades 100, 200, 250, 300, 350, 400, a workpiece formed with plastics material, with wood, a mineral material or with metal can be cut. The sawblades 100, 200, 250, 300, 350, 400 can be used, for example, in a straight form. In such a configuration, the sawblades 100, 200, 250, 300, 350, 400 can be used, for example, in motor-driven jigsaws, hacksaws, straight backed saws, veneer saws or the like. Furthermore, the sawblades 100, 200, 250, 300, 350, 400 can also be used in a circular configuration with radially outwardly oriented teeth in motor-driven table saws or hand-held circular saws.
Furthermore, it is possible to bring the sawblades 100, 200, 250, 300, 350, 400 into a hollow cylindrical shape, wherein in such a configuration free ends of the sawblade are fixedly connected to one another in a suitable manner in order to create the continuous geometry. In this way, for example, a high-efficiency so-called hole saw (circular or annular cutter) can be provided, but is not shown in the figures. Furthermore, the sawblades 100, 200, 250, 300, 350, 400 can be used for example in a motorized band saw.
Number | Date | Country | Kind |
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10 2020 211 809.4 | Sep 2020 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2021/074472 | 9/6/2021 | WO |