Abstract
A magnetic base for an electric power tool, the magnetic base having a base body in which at least one first magnet is accommodated, whose magnetic force is switchable between a maximum resulting holding force and a minimum resulting holding force. A first side is adapted to be coupled with the electric power tool, and a second side is formed opposite the first side, the second side is adapted to be mounted on a workpiece to be processed. At least one wear indicator is arranged on the second side.
Claims
1. A magnetic base for an electric power tool, the magnetic base comprising: a base body in which at least one first magnet is accommodated, whose magnetic force is switchable between a maximum resulting holding force and a minimum resulting holding force; a first side, which is adapted to be coupled with the electric power tool; and a second side opposite the first side, the second side being adapted to be mounted on a workpiece to be processed; and at least one wear indicator arranged on the second side.
2. The magnetic base according to claim 1, wherein the at least one wear indicator is provided multiple times.
3. The magnetic base according to claim 1, wherein the number of wear indicators is 2 or more, 4 or more or 6 or more, and 14 or fewer, 12 or fewer, 10 or fewer or 8.
4. The magnetic base according to claim 1, wherein the at least one wear indicator has a wear resistance which is equal to or less than the wear resistance of the second side of the magnetic base, which may be placed on the workpiece.
5. The magnetic base according to claim 1, wherein the at least one wear indicator is designed as an indentation.
6. The magnetic base according to claim 5, wherein the indentation is cast.
7. The magnetic base according to claim 1, wherein a shape of the wear indicator is a ring, a line, a circular area, and/or an ellipse.
8. The magnetic base according to claim 1, wherein the at least one wear indicator is arranged in an edge region of the magnetic base.
9. The magnetic base according to claim 1, wherein the at least one wear indicator is formed on a wear plate, which is detachably fastened to the base body.
10. The magnetic base according to claim 9, wherein the wear plate is screwed to the base body.
11. The magnetic base according to claim 10, wherein the screwing takes place from the first side of the magnetic base.
12. The magnetic base according to claim 9, wherein a side of the wear plate facing away from the base body has an essentially planar surface.
13. The magnetic base according to claim 9, wherein a groove is formed in the side of the wear plate facing away from the base body.
14. The magnetic base according to claim 13, wherein the groove has a prismatic shape.
15. The magnetic base according to claim 13, wherein the groove is oriented symmetrically to a longitudinal axis of the base body.
16. The magnetic base according to claim 1, wherein the at least one wear indicator is formed as a sensor element, which is accommodated in the magnetic base.
17. The magnetic base according to claim 16, wherein a shutoff device is provided, which deactivates the electric power tool if a predefined wear limit is exceeded.
18. An electric power tool comprising a magnetic base according to claim 1.
19. The magnetic base according to claim 1, wherein the electric power tool is a magnetic core drilling machine.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:
[0024] FIG. 1 shows a perspective view from below of a first specific embodiment of a magnetic base;
[0025] FIG. 2 shows a perspective view from below of a second specific embodiment of a magnetic base, including a wear plate;
[0026] FIG. 3 shows a perspective view from below of a third specific embodiment of a magnetic base, including a groove;
[0027] FIG. 4 shows a detailed view of a first variant of the wear indicators;
[0028] FIG. 5 shows a detailed view of a second variant of the wear indicators;
[0029] FIG. 6 shows a detailed view of a third variant of the wear indicators;
[0030] FIG. 7 shows a detailed view of a fourth variant of the wear indicators;
[0031] FIG. 8 shows a detailed view of a fifth variant of the wear indicators; and
[0032] FIG. 9 shows a sectional view along a cross-section of a further specific embodiment of the magnetic base.
DETAILED DESCRIPTION
[0033] FIG. 1 shows a perspective view from below of a first specific embodiment of a magnetic base 1, which is fastened to an electric power tool 15, namely to a magnetic core drilling machine 2. Magnetic base 1 comprises a base body 3, in which, in the illustrated exemplary embodiment, two magnets 16 are accommodated, which are designed as solenoid coils 4 and which each form an electric magnet. Due to the applied voltage, the magnetic force thereof may be switched between a maximum resulting holding force and a minimum resulting holding force. Solenoid coils 4 are each in an annular recess 5, which is formed in base body 3, and cast with a casting compound 6. Magnetic base 1 has a first side 7, which is coupled with magnetic core drilling machine 2, and an oppositely situated second side 8, which may be placed on a workpiece to be processed. Multiple wear indicators 9, which indicate the wear on magnetic base 1, are formed on this second side 8. In the illustrated exemplary embodiment, the number of these wear indicators 9 is exactly 6. Within the scope of the invention, however, the number is advantageously 2 or more, preferably 4 or more and particularly preferably 6 or more and further advantageously 14 or fewer, preferably 12 or fewer and particularly preferably 10 or fewer and exceptionally preferably 8. Wear indicators 9 are formed as indentations 10 and have a circular shape. To prevent a penetration of chips into wear indicators 9, indentations 10 are cast. The material used for the casting has a wear resistance which is equal to or less than the wear resistance of second side 8 of magnetic base 1, which may be placed on the workpiece. This then achieves the fact that the wear on wear indicators 9 is at least as great as the wear on second side 8 of magnetic base 1, which is placed on the workpiece to be processed. As is further apparent from FIG. 1, wear indicators 9 are arranged in the edge region of magnetic base 1. since according to experience the wear is the greatest in this region. In the illustrated exemplary embodiment, the distance of wear indicators 9 from the edge of the magnetic base is approximately 5% of the length of magnetic base 1. If the user now determines that wear indicators 9 have worn down, he must subsequently present magnetic base 1 or entire magnetic core drilling machine 2 for servicing.
[0034] FIG. 2 also shows a perspective view from below of a second specific embodiment of magnetic base 1 according to the invention. In this specific embodiment, the total of eight wear indicators 9 are formed in a wear plate 11, which is detachably screwed to base body 3. The screwing takes place from first side 7 of magnetic base 1, i.e. from the side on which magnetic core drilling machine 2 is fastenable. The side of wear plate 11 facing away from base body 3 has an essentially planar surface and is therefore particularly suitable for fastening magnetic base 1 to an equally planar workpiece. Wear plate 11 is designed in such a way that recesses 5 accommodating solenoid coils 4. which are cast with casting compound 6, are partially covered by webs 18. It is furthermore apparent from FIG. 2 that an electric plug connector 19, illustrated in an interrupted manner, is formed on first side 7 of magnetic base 1, with the aid of which it is possible to couple the magnetic base with the controller of a magnetic core drilling machine 2.
[0035] In the perspective view from below of the third specific embodiment of magnetic base 1 illustrated in FIG. 3, it is apparent that, in this example as well, wear indicators 9 are mounted on a wear plate 11 screwed to base body 3. In this specific embodiment, a groove 12 is formed in the side of wear plate 11 facing away from base body 3. In the illustrated exemplary embodiment, this groove 12 has a prismatic shape, which makes it possible to fasten magnetic base 1 to workpieces which do not have a planar surface, for example to pipes. Wear indicators 9 are also formed within this groove 12. This groove 12 is oriented symmetrically to a longitudinal axis 13 of base body 3. Due to the ability to screw wear plate 11, it is possible for the user to adapt magnetic base 1 to different surface contours.
[0036] FIGS. 4 through 8 show detailed views of different shapes of wear indicators 9. which differ from each other with respect to their design. Wear indicators 9 illustrated in FIG. 4 have a circular disk-shaped design, while wear indicators 9 illustrated in FIG. 5 each have a triangular shape. Wear indicators 9 illustrated in FIG. 6, on the other hand, are each formed from concentric rings having different radii. Wear indicators 9 used in FIG. 7 are each multiple parallel lines, while wear indicators 9 in the specific embodiment according to FIG. 8 are finally designed as lines arranged perpendicularly with respect to each other.
[0037] FIG. 9 shows a sectional view of a cross-section of magnetic base 1. This sectional view shows, in particular, that at least one of wear indicators 9 in the illustrated exemplary embodiment is formed as a sensor element 14. The latter is inserted from second side 8 into a corresponding receptacle 17 in base body 3 of magnetic base 1. If a predefined wear limit is exceeded, this makes it possible to deactivate magnetic core drilling machine 2 with the aid of a shutoff device, which is connected to the controller of magnetic core drilling machine 2. Receptacle 17 is closed by wear plate 11 from second side 8 of base body 3. Screw receptacles 20 are also apparent in FIG. 9, win which screws may be accommodated for the purpose of screwing base body 3 to wear plate 11.
[0038] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.
