DK174530B1 - Circular sawblade, especially for angle grinder, contains radial and axial debris removal holes and is provided with radially offset hard metal blades - Google Patents

Abstract

The sawblade (2) is provided with both radial and axial holes (8, 16) for removing debris and is also provided with radially offset hard metal blades (4, 6). A circular sawblade for a hand-held machine saw with a guard around the sawblade mouth, preferably an angle grinder, has a constant external diameter and contains inspection holes for the user to monitor sawing work during use. The sawblade is provided with both radial and axial holes for removing debris and is also provided with radially offset hard metal blades. An Independent claim is also included for a hand-held machine saw fitted with this sawblade, the guard being mounted at the head of the saw in a threaded hole opposite to the threaded hole in which the side handle is mounted, the guard extending in a downwards direction relative to the sawblade, towards the standard saw guard.

Description

DK 174530 B1 i

The present invention relates to a circular cutting disc for handheld tool with a protective shield at the outlet of the cutting disc, preferably an angular grinder where the cutting disc is chip-bearing, having a permanent outer diameter and with inspection openings through which the user can monitor the work using the cutting disc. The invention further relates to a handheld tool having such a circular cutting disc as well as the use of the mentioned tool.

It is generally known to use cutting and grinding wheels for machining various materials such as plastics, metals, stones and other natural materials. Many of the 10 known types of cutting and grinding discs are of the type worn during use by minimizing the diameter and / or thickness of the disc. These types of slices can be collectively referred to as '' non-chip ''.

Furthermore, chip-type types of cutting discs are also known for use on angle grinders. For example, a cutting disc is disclosed in US 4,776,402, which is intended for the care of grazing animals' hoofs. This cutting disc is chip-proof but cannot be re-grinded in an economically sound manner and its inspection openings are not optimal in terms of location and size. Furthermore, the disc is not suitable for purposes other than the above and does not have sufficient opening for chip removal.

20

From DE 44 19 026, another chip cutting tool is known for mounting on an angle grinder. This disc is intended for use in wood and is a comparatively complicated tool with interchangeable plates at the periphery and with a design resembling a "cup", and does not otherwise have inspection openings or chip exits as such.

25

Further, DE 31 46 648 discloses a chip cutting disc for the care of clefts, but this cutting disc is exclusively for cleft care and is also not carried out with inspection openings and with axial chip outlets. Furthermore, the cutting disc according to DE 31 46 648 is made with a disc geometry which is highly expensive on the 30 cutting disc and any grinding of the tool will not be cheap, especially because the geometry of the cutters is complicated.

DK 174530 B1 2

SUMMARY OF THE INVENTION It is an object of the invention to provide a circular cutting disc for a handheld tool as well as such an angular grinder-type tool, with a rotating and shaving cutting disc with associated protective screen, which has a wide application and which can be manufactured and reshaped in an economically sound manner , 5 and which gives the user optimal visual feeling with the work done. Furthermore, the purpose is to indicate one tool that can replace up to several other tools and that does not unnecessarily load the tool's engine and gear with large rotating masses.

The invention discloses a circular cutting disc which differs from the prior art 10 in that the cutting disc is of radial as well as with axial openings for chip exits, that the cutting disc has radially offset cemented carbide inserts.

Further, the invention discloses a handheld tool having such a circular cutting disc and which differs from the prior art in that the guard is mounted at the head of the angle grinder in an opposite threaded hole to the side hole of the angle grinder, wherein the guard screen relative to the cutting disc has a downwardly extending and extending down to the standard angle grinder shield.

In addition, the use of a circular cutting disc according to the invention is indicated for machining clefts, aluminum, plexiglass, PVC, iron, stone, wood and for tearing off tires prior to reunification.

With a tool with such a cutting disc, a stable and easily manageable tool is obtained for machining virtually all different material groups. The disc is made of 25 with radial chip exits extending from a center region to the periphery of the disc. Immediately behind the cutting insert located at the trailing edge of the radial chip outlet, there are inspection openings which have the additional function of acting as axial chip outputs. Together, the radial and axial chip yields ensure optimum removal of chips from the machined area and at the same time reduce the weight of the 30 cutting disc. The reduced weight has the lucky effect that the angle grinder is not so heavily loaded at start-up and also has the effect that the gyro effect in the cutting disc is minimized, which results in a significantly easier handling of the tool.

3 DK 174530 B1

A cutting disc according to the invention typically has six or more inserts. These inserts are radially offset in such a way that some inserts are positioned at the periphery of the cutting disc and machining an outer annular region and other inserts are located closer to the center of the cutting disc, and as a result, one or more annular regions work closer to the cutting disc units. In this way, the load on the angle grinder is further minimized as each cutting does not take a full width chip.

Another important parameter for different material groups is the radial approach of the cutters to the material, which can have either a positive or a negative approach angle. A positive approach is where the outer end of the cutter strikes the material first, thereby removing material in an inward motion. This approach is suitable for soft materials where the blades can easily penetrate the material. A negative approach is where the inner end of the cutter strikes the material first and removes the material in an outward motion. This approach is particularly suitable for hard materials or where the surface of the material is uneven.

A tool according to the invention also includes a protective shield which is designed to be mounted on a standard angle grinder. The function of this screen is to protect the user from being hit by chips from the cutting disc. This protection 20 is obtained by placing an appropriate shield on the side of the angle grinder where the disc has its outlet.

A cutting disc according to the invention can be used for machining many different materials, among other things for caring for hoofs on livestock, eg on cows, for machining light metals such as aluminum, and for plastic types such as plexiglass, PVC and other plastic materials. The disc can also be used with great advantage for sharpening metal parts, for example steel parts prior to welding and for finishing weld seams after welding and of course for ordinary machining of different metals. Another material where the cutting disc is useful is wood, where the cutting disc is particularly attractive in connection with the fitting of timber and the like at construction sites and in workshops. Materials such as stone, be it natural stone, brick or beech can also be machined with the cutting disc, and finally it should be emphasized that the cutting disc is extremely suitable for tearing off tires before retreading.

Several of the materials mentioned have the property of being deposited in and on known cutting and grinding tools. The cutting disc according to the invention has the surprising advantage that due to its very "open" disc design, an optimal removal of chips and an optimal cooling of the cutting process itself takes place. In this way, it is possible to process materials such as special aluminum and PVC - among others. others - without the tool heating up the workpiece, resulting in poor surface quality.

In one embodiment of a cutting disc according to the invention, the cutting disc is formed on its periphery with a guide bar behind each cutting, which forms a fixed edge around an axial chip clearance and which also forms one side in a radial chip clearance. In this way, a strong cutting disc is obtained, which can withstand minor blows without any distortion of the disc. The maximum size of the axial chip outputs and inspection openings is reached at the same time.

In another embodiment of the cutting disc, it is provided on its periphery with a guide bracket behind each cutting forming a fixed peripheral, interrupted by the radial chips, where an axial chip and a radial chip output are in open communication with each other. This solution provides the widest possible open area on the cutting disc, thus providing the best opportunity to "peek" through the disc as it works, and this variant also gives the chips the best opportunity to get away.

In a particular variant, a cutting disc may be designed such that the radial chip outlets 25 with cutters pulled away from the peripheral edge and towards the center of the cutting disc have a recess in front of the tooth. This recess allows easier access with grinding tools when the disc's cutting edge needs to be reshaped.

The cutting disc will normally be designed to be tapered on at least one side and preferably plane on another side, and usually the cutters will be mounted on the tapered side of the cutting disc, but may of course be mounted on a flat side of the cutting disc. Alternatively, inserts may be mounted on both sides of the cutting disc. On 5 DK 174530 B1 cutting discs with inserts on both sides these will often be designed so that they are opposite to the opposite. Understanding that if the cutter on one side sits at the periphery of the cutting disc then the cutter on the opposite side will be located closer to the center of the cutting disc.

5

With these alternatives, a cutting disc according to the invention can be made with different properties. Particular attention should be paid to the advantages of mounting the inserts on a tapered side of the cutting disc. Namely, this location has the advantage that only a small area of the cutting disc is in '' engagement '' with the material being machined, and in this way it becomes easier to perform precise work with a tool mounted with a cutting disc according to the invention. However, there may be various tasks where other of the aforementioned placement options may be more optimal, for example mention can be made of wood milling or the like.

A handheld tool according to the invention, with the positioning and downward extension of the protective screen, will provide an optimal derivation of chips from the workpiece being processed, thus securing the user's hands against contact with them. The chips from the cutting disc can be hot, sharp or simply of a size that hits hard when they strike a hand or other body part.

The invention will now be described with reference to the accompanying drawings, which, without limitation, show a preferred embodiment of a hand tool with a cutting disc and a protective shield according to the invention, in which: 1 shows a cutting disc with cutting edges on the conical side and with a positive approach angle; FIG. 2 as FIG. 1 but viewed from the side, FIG. 3 as FIG. 1 and 2 but viewed from the user's point of view; 4 shows a cutting disc with a negative approach angle; FIG. 5 shows a disc with contiguous chip exits / inspection openings; FIG. 6 shows a double conical cutting disc with cutting edges on both sides; FIG. 7 as FIG. 6, but seen from the side, DK 174530 B1 6 fig. 8 shows a tapered cutting disc, the cutter having a positive angle; FIG. 9 shows a tapered cutting disc, the cutter having a negative angle; FIG. 10 shows a tapered cutting disc where the cutting is at an angle of 0 °, and fig. 11 shows an angle grinder with cutting disc and with mounted guard.

5 In FIG. 1, 2 and 3, the same cutting disc 2 is seen from different sides. The disc 2 has six offset cutters 4.6, where at the radial chip exits 8 at the inner cutters 4 a recess 10 is made in front of the cutter 4. As mentioned above, this recess 10 causes the sharpening of the cutter 4 to be considerably facilitated. On this disc 2, every other cutter 6 is placed 10 at the periphery 12 and the other 4 are located closer to the center 14 of the disc.

The disc 2 shown also has axial chip outputs 16, and with a positive approach angle for the inserts 4, 6, where the outer end of the insert 4, 6 strikes the material first, thereby removing material in an inward movement. This approach is suitable for 15 soft materials where the cutters 4.6 can easily penetrate the material.

On the disc 2 shown, the axial chip outputs 16 are surrounded by guide brackets 18. These guide brackets 18 are instrumental in ensuring that the cutting edge 4, 6 does not take too large a chip and at the same time gives the disk 2 stability. The disc 2 has a central hole 14 for mounting on a 20 angle shaft 24 (see Fig. 11). The center part of the disc is in the shown embodiment with a recess 20 so that the weight of the disc is partly reduced and partly to enable mounting on a standard angle grinder 26, on which only discs with a thickness of up to approx. 5 - 6 mm. The disc 2 shown has a maximum thickness of approx. 12 mm on the tapered part and has a thickness of approx. 4 mm at the periphery 12. At the center hole 14 which 25 has a diameter of approx. 23 mm, the recess 20 is made with a diameter of approx. 50 mm and the center thickness is approx. 6 mm. Finally, the disc 2 shown has a diameter of approx. 100 mm. Moreover, it is clear to anyone with insight in this area that such a disc 2 can be easily carried out with dimensions other than those specified here.

FIG. 4 shows a cutting disc 2 made with a negative approach angle, the inner end of the cutting 4, 6 hitting the material first and removing the material in one outward movement. This approach is particularly suitable for hard materials or where the surface of the material is uneven, for example, such a disc will often be used for machining stone materials.

DK 174530 B1 7

FIG. 5 shows a variant of the cutting disc 2, wherein the guide bracket 18 is constituted by a broken peripheral edge extending between the cutting edge 4, 6 and to the subsequent radial chip exit 8. On this disc 2 there is open connection 22 between the radial chip exit 8 and the axial chip clearance 16 and the guide bracket 18 are shown with the same dimension as in FIG. 1. Depending on the area of application of the cutting disc, the guide bracket 18 can be dimensioned to obtain the required strength. The cutting disc 2 in FIG. 4, like the disc 20 of FIG. 1-3 six inserts 4, 6 continued in two positions, but the inserts 4, 6 could easily have been positioned in three or more positions, and the number of inserts 4, 6 could have been higher or lower.

In FIG. 6 and 7, a cutting disc 2 is seen which is tapered on both sides and which is furthermore 15 with offset cutting edges 4, 6 on both sides of the cutting disc 2. In particular, it is seen in FIG. 7 how the inserts 4, 6 are positioned not only offset on one side, but also offset relative to the other side of the cutting disc 2. This type of cutting disc 2 can as well as a disc 2 which is tapered on one side and flat on a second side being with "broken" guide bracket 18 as shown in FIG. 5th

20

Finally, FIG. 8,9 and 10 are various designs of the carbide cutter 4, 6, the three figures all showing a cutting disc 2 with an enlarged detail regarding the angle of the cutter. The angle referred to herein is called the chip angle and is shown in FIG. 8 as a positive angle, in FIG. 9 as a negative angle and finally in FIG. 10 with an angle of 25 degrees to the axial center line of the cutting disc. This different design of the cutting angle of the insert is well known to those skilled in the art of manufacturing and grinding cutting tools.

FIG. 11 shows a hand-held angle grinder 24, with side handles 26, where a cutting disc 2 30 is mounted and where the standard standard shield 28 is supplemented by a protective shield 30 according to the invention. This guard 30 is mounted in a threaded hole on the side of the angle grinder head 32. This additional guard 30 DK 174530 B1 8 provides an improved shielding against chips being thrown out and away from the working area.

In FIG. 11, it also appears that the abutment face of a cutting blade is not a flat surface but a tapered surface, which provides a sufficient area of engagement, but at the same time achieves a very important minimal heat development - due to friction - at the workplace. This minimal heat development in combination with the very open design on the cutting disc 2 ensures good machining results in many metals and plastics materials, which usually cannot be processed without problems.

Claims (10)

9 DK 174530 B1 l. Circular cutting disc (2) for handheld tool (24) with protective shield (30) at the cutout outlet, preferably an angle grinder where the cutting disc is chip-bearing, with a permanent outer diameter, where the cutting disc is with inspection openings (16) , through which the user can monitor the work using the cutting disc, characterized in that the cutting disc (2) has radial as well as axial openings (8,16) for chip outputs, that the cutting disc has radially set carbide inserts (4,6). Circular cutting disc according to claim 1, characterized in that the cutting disc on its periphery is provided with a guide bracket (18) behind each cutting insert (4,6) which forms a fixed edge around an axial chip clearance (16) and which also forms one side in a radial chip exit (8). Circular cutting disc according to claim 1, characterized in that the cutting disc on its periphery 15 is provided with a guide bracket (18) behind each cutting insert (6) forming a fixed peripheral, interrupted by the radial chip outputs (8), chip exit (16) and a radial chip exit (8) are in open communication (22) with each other. Circular cutting disc according to any one of claims 1 to 3, characterized in that the radial chip outlets (8) with cutters pulled away from the circumferential edge towards the center of the cutting disc have a recess (10) in front of the cutter (4). ). Circular cutting disc according to any one of claims 1 to 4, characterized in that the cutting disc (2) is tapered on at least one side and preferably plane on another side. 25 Circular cutting disc according to any one of claims 1 to 5, characterized in that the cutters (4,6) are mounted on a conical side of the cutting disc (2). Circular cutting disc according to any one of claims 1 to 5, characterized in that the cutters (4,6) are mounted on a flat side of the cutting disc (2). 10 DK 174530 B1 Circular cutting disc according to any one of claims 1 to 5, characterized in that inserts (4,6) are mounted on both sides of the cutting disc (2). Handheld tool (24) with a circular cutting disc (2) according to any of claims 1 to 8, characterized in that the protective shield (30) is mounted at the angle grinder head (32) in an opposite threaded hole for the threaded angle grinder side handles (26) are mounted in which the guard (30) with respect to the cutting disc (2) has a downward extension and extends down to the standard guard of the angle grinder (28). 10 Use of a circular cutting disc (2) in a handheld tool (24) with a protective shield (30), preferably an angle grinder, according to claims 1 - 9, for machining clefts, aluminum, plexiglass, PVC, iron, stone, wood and for tire removal prior to retreading.