EP1964644B1 - Motor-driven grinder - Google Patents

Description

The invention relates to a motor-driven grinder with a grinding head and a handle bar for holding the grinder, wherein the grinding head is arranged pivotable relative to a grinding head facing the handle end portion of the handle bar about at least one pivot axis and the grinding head a suction hood for sucking in the grinding of a Workpiece resulting dust, which is connected via a flexible suction hose with the handle end part, wherein the suction hose projects at a distance from the pivot axis of the grinding head and extends with a curved course a little way around the pivot axis to the handle end part.

Such grinding devices - also called long-neck sander - can be used for grinding of building walls and ceilings. In this case, the abrasive head carrying a corresponding abrasive is held by means of the handle bar against the surface to be ground. The resulting dust during grinding is to keep the environment by suitable Openings, channels or the like in a sanding abrasive pad or the like of the grinding head sucked into the suction hood and from there through the suction hose to the handle end, from where the grinding dust passes through the handle bar to a releasably connected to the handle bar outer suction hose, the a vacuum cleaner leads.

Since the grinding head is pivotally connected to the handle end part, it retains its position during grinding regardless of the current inclination of the handle bar.

Such a grinder is for example from the DE 696 15 879 T2 known.

Proceeding from this, the present invention seeks to provide a grinding device of the type mentioned, in which an uncontrolled swinging back and forth of the grinding head when not in use of the grinding device avoided and thus the grinding head is held in a position as defined as possible relative to the handle end , so that a secure placement on the workpiece is made possible.

This object is achieved in that the bending elastic trained suction hose when not in use of the grinder forms the grinding head in a starting pivotal position with respect to the handle end portion holding member by the suction hood opposite end portion of the suction hose engages around a pivot axis parallel to the hinge axis pivotally connected to the handle end portion pivot member which is spring loaded so that the suction hose is acted upon in the direction away from the grinding head end of the suction hose.

The suction hose presses against the grinding head, so that the grinding head tries to pivot towards the handle end part. On the other hand, the pivoting element exerts on the suction hose an opposite pivoting moment on the grinding head, so that there is a defined output pivotal position for the grinding head, in which the grinding head forces and moments is in equilibrium.

The angular position of the grinding head in the output pivot position is therefore dependent on the size of the force acting on the pivot member spring force and also on the length of the suction hose. This spring force will therefore be chosen to be large enough to obtain a favorable for the handling and storage of the grinder output pivot position of the grinding head.

The output pivot position is further influenced by the bending elasticity or by the rigidity of the suction hose. In this context, it is expediently provided that the suction hose contains a spring wire spiral. In this case, the suction hose is preferably a spiral hose with embedded in the hose wall spring wire spiral.

Further expedient embodiments of the invention are specified in the subclaims.

Figur 1

ein erfindungsgemäßes Schleifgerät mit in seiner Ausgangs-Schwenklage befindlichem Schleifkopf in Seitenansicht, wobei vom Griffstab nur das Griff-Endstück dargestellt ist,

Figur 2

das Schleifgerät nach Figur 1 in Draufsicht gemäß Pfeil II,

Figur 3

das gleiche Schleifgerät in Vorderansicht gemäß Pfeil III in Figur 1,

Figur 4

einen das Schwenkelement enthaltenden Ausschnitt aus Figur 1 in vergrößerter Darstellung, wobei die dem Betrachter zugewandte Halbschale des Schwenkelements entfernt ist,

Figur 5

die Anordnung nach Figur 4 im Schnitt gemäß der Schnittlinie A-A in Figur 4,

Figur 6

das gleiche Schleifgerät in der Figur 1 entsprechender Seitenansicht, wobei der Schleifkopf um eine erste Schwenkachse aus seiner Ausgangs-Schwenklage verschwenkt ist,

Figur 7

das Schleifgerät nach den Figuren 1 bis 6 in der Figur 2 entsprechender Draufsicht, wobei der Schleifkopf um eine zur ersten Schwenkachse rechtwinkelige zweite Schwenkachse verschwenkt ist,

Figur 8

die Anordnung nach Figur 7 in der Figur 3 entsprechender Vorderansicht,

Figur 9

ein abgeschnittenes Absaugschlauchstück in detaillierter gezeichneter Seitenansicht (in den Figuren 1 bis 8 ist der Absaugschlauch nur schematisch gezeichnet) und

Figur 10

das Absaugschlauchstück nach Figur 9 im Längsschnitt in vergrößerter Teildarstellung.

An embodiment of the invention will be explained with reference to the drawing. Show it:

FIG. 1

a grinder according to the invention with a grinding head located in its starting pivoting position in side view, wherein only the handle end piece is shown by the gripping rod,

FIG. 2

the grinder after FIG. 1 in plan view according to arrow II,

FIG. 3

the same grinder in front view according to arrow III in FIG. 1 .

FIG. 4

a section containing the pivot element FIG. 1 in an enlarged view, wherein the observer facing half-shell of the pivoting element is removed,

FIG. 5

the arrangement after FIG. 4 in section along the section line AA in FIG. 4 .

FIG. 6

the same grinder in the FIG. 1 corresponding side view, wherein the grinding head is pivoted about a first pivot axis from its output pivot position,

FIG. 7

the grinder after the FIGS. 1 to 6 in the FIG. 2 corresponding top view, wherein the grinding head is pivoted about a second pivot axis perpendicular to the first pivot axis,

FIG. 8

the arrangement after FIG. 7 in the FIG. 3 corresponding front view,

FIG. 9

a cut Absaugschlauchstück in detail drawn side view (in the FIGS. 1 to 8 the suction hose is drawn only schematically) and

FIG. 10

the suction hose piece after FIG. 9 in longitudinal section in an enlarged partial view.

From the drawing, a grinder 1 held by hand during use is shown in the form of a so-called long-necked grinder, which can be used for grinding building ceilings and walls.

The grinder 1 has a grinding head 2, which is arranged at the end of a handle bar, on which the grinder 1 is held, so that grinding work can be performed in height. Of the handle bar only the grinding head 2 facing handle end part 3 is shown. The otherwise omitted handle bar extends in extension of the handle end part. 3

The grinding head 2 has a sanding pad 4, which is driven during operation by a device motor 5 to a rotational movement about the rotation axis 6. At the handle end portion 3 opposite bottom 7 of the grinding plate 4 is or an abrasive, for example in the form of an abrasive sheet attached, which is held during grinding against the surface to be ground.

The grinding head 2 is arranged pivotable relative to the handle end part 3 about a first pivot axis 8, so that itself the sanding pad 4 can create regardless of the inclination of the handle bar to the surface to be ground. Conveniently, the grinding head 2 is also arranged pivotable about a perpendicular to the first pivot axis 8 extending second pivot axis 9 relative to the handle end part 3, so that the grinding head 2 is hinged gimbal so to speak on the handle end part. The handle end portion 3 has two the grinding head 2 a piece far on both sides cross-holding arms 10, 11, at the ends of the first pivot axis 8 is arranged. At the grinding head section 12, which is mounted so as to be pivotable at the first pivot axis 8, the sanding plate section 13 containing the sanding pad 4 is pivotably mounted about the second pivot axis 9.

On the grinding head 2 and thereby on the underside of the grinding head 2 forming grinding head section 13, a suction hood 14 is arranged for sucking the resulting in the grinding of a workpiece dust at the top of the grinding plate 4. The suction hood 14 is connected via a flexible suction hose 15 with the handle end part 3, wherein the suction hose 15 at a distance from the first pivot axis 8 from the grinding head 2 and thereby of the lower grinding head section 13 stands up and with a curved course a distance to the first pivot axis eighth around the handle end part 3 runs. On the grinding head 2 are a suitable connection piece 16 and a cap sleeve 17 arranged for connecting and securing the facing hose end. The connection of the opposite end of the suction hose 15 with the handle end part 3 will be explained below.

At the handle end part 3, the suction hose 15 is followed by a suction channel 18 arranged in the handle end section 3, which continues in the further handle bar up to a connection point at which a suction hose leading to a vacuum cleaner can be connected. In operation, the resulting on the workpiece grinding dust is sucked through suitable openings in the abrasive and sanding pad 4 into the suction hood 14 and from there through the suction hose 15, the handle bar and the outer suction hose to the vacuum cleaner. The air duct in the handle bar interested in this case no further. It could also take place along the outside of the handle bar by means of a further suction hose extending along the handle bar. The suction tube 15 is flexurally elastic and expediently contains an in FIG. 1 only schematically indicated spring wire spiral 19, expediently in that the suction hose 15 is a spiral hose, in which the spring wire spiral 19 is embedded in the hose wall. In the FIGS. 1 to 8 the suction tube 15 is drawn for simplicity's sake only as a simple tube. Its design as a spiral hose with spring wire spiral goes out of the FIGS. 9 and 10 out.

The suction hose 15 forms a non-use of the grinding device 1, the grinding head 2 in a starting pivotal position with respect to the handle end part 3 holding holding element. In the illustrated embodiment, the arrangement is such that the from the FIGS. 1 to 3 resulting pivotal position is the output pivotal position from which the grinding head 2 can be pivoted in both directions, such as in the FIG. 6 prominent pivotal position. In this way, the sanding pad 4 can always create the entire surface of the sanding surface during grinding, regardless of the inclination of the handle bar held by the user. If you take the grinding head 2 away from the surface to be ground, it automatically returns to its original pivot position.

Contributes to this, that the suction hose 15 so to speak forms a spiral spring. Furthermore, engages on the suction hood 14 opposite end portion 20 of the suction hose 15 to a pivot member 21 which is pivotally connected to a first pivot axis 8 to the hinge axis 22 pivotally connected to the handle end part 3. The pivoting element 21 is spring-loaded so that it is the suction hose 15 in from the sanding head end of the suction hose 15 directed away 24 direction.

Due to the bending elasticity and rigidity of the suction hose 15, the suction hose 15 presses from above against the exhaust hood 14 having the lower grinding head section 13 and thus against the grinding head 2, so that the grinding head 2 in FIG. 1 wants to pivot counterclockwise about the first pivot axis 8. However, this pivoting counteracts the spring-loaded pivoting element 21, which keeps the associated suction hose end portion 20 so to speak in the direction of the grinding head 2 and thus pulls the suction hose 15 and with this the grinding head 2 in the clockwise direction. Thus, two mutually opposite pivoting moments occur on the grinding head 2, which cancel each other out in the output pivoting position. If the grinding head 2 is pivoted out of the output pivot position during the grinding process, the two pivoting moments no longer cancel each other, so that a restoring torque corresponding to the difference of the pivoting moments occurs, which returns the grinding head 2 to its original position when it is removed from the surface to be ground. Swing back pivot position.

The force acting on the pivot member 21 spring force is chosen so as to obtain the desired output pivot position.

The suction hose 15 extends in the output pivot position in a transverse to the first pivot axis 8 level, as in particular FIG. 2 is apparent. The handle of the grinder extends in the same plane.

The suction hose 15 is connected to the grinding head 2 facing away from the top of the handle end part 3 to this. In this case, the suction hose end portion 20 with the then bent to the first pivot axis 8 extending holding arms 10, 11 in side view forms an acute angle, such as from FIG. 1 is apparent. The suction hose 15 extends in front of the holding arms 10, 11 with a curved course down to the grinding head. 2

As already mentioned, the device motor 5 is seated on the grinding head 2 and thereby on its grinding head section 13 containing the sanding pad 4. The device motor 5 is eccentrically with respect to the sanding pad 4 and thus in side view FIG. 1 arranged next to the first pivot axis 8. Conveniently, it is located in the output pivot position of the grinding head 2 below the handle end part 3. Therefore, the gravitational force of the device motor 5 exerts a pivoting moment on the grinding head 2.

The pivot axis 8 is between the junction of the suction hose 15 with the grinding head 2 and the Schleifgerätemotor 5, that is, the force exerted by the suction hose 15 and the device motor 5 on the grinding head 2 forces attack on both sides of the first pivot axis 8 on the grinding head 2. It has been described above that the suction hose 15 holds the grinding head 2 in the starting pivoting position with the aid of the pivoting element 21. It is understood that these parts and the force acting on the pivot member 21 spring force are designed so that the force exerted by the device motor 5 pivoting moment is compensated.

The pivoting element 21 expediently has a swiveling sleeve 25 enclosing the suction hose end region 20. Further, the pivot member 21 has two on both sides of the suction hose from the pivot sleeve 25 projecting bearing leg 26, 27 which are pivotally mounted on the handle end part about the hinge axis 22. The two bearing legs 26, 27 are in the direction of the suction hose end portion 20 from the pivot sleeve 25 to the handle end part 3 down from. The two bearing legs 26, 27 are each mounted on a protruding from the handle end part 3 bearing projection 28, 29. In this case, the two bearing projections 28, 29 each have a pivot pin 22 forming the bearing pin 30, 31, on which the associated bearing projection 28, 29 of the pivot member 21 is mounted.

The pivoting element 21 is formed in the embodiment of two half-shell elements 32, 33 which abut from opposite sides of the suction hose end portion 20 and are detachably connected to each other. In this case, each half-shell part 32, 33 forms one half of the pivot sleeve 25 and the facing bearing legs 26, 27. In FIG. 4 the viewer facing half-shell element 32 is removed.

The two half-shell parts 32, 33 can be screwed together.

Out FIG. 4 are two receiving holes 34, 35 on the half-shell part 33 for receiving connecting screws can be seen. At the other half-shell part 32 are corresponding receiving holes.

The end region 20 of the suction tube 15 extends through the pivot sleeve 25 and has an exit from the pivot sleeve 25, extending to the handle end part 3 end portion 36. In this case, the suction tube end portion 20 is separated within the pivot sleeve 25, so that the emerging from the pivot sleeve 25 end portion 36 is formed by a separate from the other suction hose end portion 20 tube portion 37.

In particular from FIG. 4 It can be seen that the cut-off, the end portion 36 forming the tube part and this frontally opposite other suction hose end portion within the pivot sleeve 25 are connected by a plugged into both pipe sockets 38 with each other.

The emerging from the pivot sleeve 25 end portion 36 of the suction tube 15 extends between the bearing legs 26, 27 and bearing projections 28, 29 through to the handle end part 3, in particular from the Figures 2 and 5 is apparent.

The spring force acting on the pivoting element 21 is applied by a torsion spring 39. This is expediently a torsion coil spring, which is arranged around the hinge axis 22 between one of the bearing legs (bearing leg 26) of the pivot member 21 and the associated bearing projection 28 of the handle end part 3 and is supported on this.

The two bearing legs 26, 27 are inserted in the axial direction of the hinge axis 22 respectively on the associated bearing projection 28, 29, wherein each of a bearing leg and a bearing projection formed pair one about the respective bearing pin 30, 31 and mounted on this bearing part of the associated bearing projection 28, 29 extending around annular space 40, 41 forms. In one of these annuli (annulus 40), the torsion spring 39 is housed, the spring ends 42, 43 are supported on the respective bearing leg 26 and the associated bearing projection 28.

As already described, the grinding head 2 is pivotable not only about the first pivot axis 8 but also about the second pivot axis 9, which runs at right angles to the first pivot axis 8 and to the axis of rotation 6. In the FIGS. 7 and 8th the grinding head 2 is shown pivoted about the second pivot axis 9. Both pivoting possibilities about the first pivot axis 8 and the second pivot axis 9 result in a gimbal suspension of the grinding head 2, so that the sanding pad 4 can invest in any inclined position of the grinding head 2 to the wall to be ground. Also, a pivoting about the second pivot axis 9 grinding head moves when it is removed from the wall, in the output pivot position according to the FIGS. 1 to 3 back.

However, it is also possible to give the grinding head 2 a rotated about the second pivot axis 9 output pivot position. For this purpose, at least one of the end regions of the suction tube 15 can be rotatably connected to the suction hood 14 or the handle end section 3, in such a way that the respective suction hose end region automatically holds or can be detected in the set rotational position is. By twisting the suction tube 15 is so to speak twisted in itself, so that its level is no longer level. The suction hose then runs correspondingly wound, as for example in FIG. 8 is shown.

Claims (17)

1. Motor-driven grinder with a grinding wheel head and a handle bar to hold the grinder, wherein the grinding wheel head is mounted so as to be pivotable around at least one pivot axis relative to a handle end-section of the handle bar facing the grinding wheel head, and the grinding wheel head has an extraction hood to suck up the dust occurring during grinding of the workpiece and which is connected to the handle end-section via a flexible suction hose, wherein the suction hose extends outwards from the grinding wheel head with clearance from the pivot axis, and runs in a curved path around and a short distance from the pivot axis to the handle end-section, characterised in that the suction hose (15) which is flexible in bending forms a holding element holding the grinding wheel head (2) in an initial pivot position relative to the handle end-section (3) when the grinder is not in use, by means of a pivoting element (21) connected to the handle end-section (3) and pivotable around a hinged axis (22) parallel to the pivot axis (8) which acts on the end area (20) of the suction hose (15) opposite the extraction hood (14) and is spring-loaded so that the suction hose (15) is biased in the direction away from the grinding wheel head side of the suction hose (15).
2. Grinder according to claim 1,characterised in that the suction hose (15) contains a wire spring spiral (19).
3. Grinder according to claim 2, characterised in that the suction hose (15) is a spiral hose with a wire spring spiral (19) embedded in the hose wall.
4. Grinder according to any of claims 1 to 3 characterised in that, in the initial pivot position, the suction hose (15) runs in a plane at right-angles to the pivot axis (8).
5. Grinder according to any of claims 1 to 4, characterised in that the grinder motor (5) is located on the grinding wheel head (2) and the pivot axis (8) is arranged between the connection point of the suction hose (15) to the grinding wheel head (2) and the grinder motor (5).
6. Grinder according to any of claims 1 to 5, characterised in that the pivoting element (21) has a pivoting sleeve (25) encompassing the suction hose (15).
7. Grinder according to claim 6, characterised in that the pivoting element (21) has two bearing arms (26, 27) extending from the pivoting sleeve (25) either side of the suction hose (15) and pivotably mounted on the handle end-section (3) around the hinged axis (22).
8. Grinder according to claim 6 or 7, characterised in that the pivoting element (21) is formed by two half-shell sections (32, 33).
9. Grinder according to claim 7 or 8, characterised in that each of the two bearing arms (26, 27) is mounted on a bearing projection (28, 29) extending outwards from the handle end-section (3).
10. Grinder according to any of claims 5 to 9, characterised in that the end area (20) of the suction hose (15) runs through the pivoting sleeve (25) and has an end section coming out of the pivoting sleeve (25) and running towards the handle end-section (3).
11. Grinder according to claim 10, characterised in that the end area (20) of the suction hose (15) is split inside the pivoting sleeve (25), so that the end section (36) coming out of the pivoting sleeve (25) is formed by a hose part (37) separate from the rest of the suction hose end area.
12. Grinder according to claim 11, characterised in that the separate hose part (37) and the remainder of the suction hose end area (20) within the pivoting sleeve (25) are joined together by a pipe connection (38) inserted into each part.
13. Grinder according to any of claims 9 to 12, characterised in that the end section (36) of the suction hose (15) coming from the pivoting sleeve (25) runs through between the bearing arms (26, 27) and the bearing projections (28, 29) to the handle end-section (3).
14. Grinder according to any of claims 1 to 13, characterised in that the pivoting element (21) is spring-loaded by a torsion spring (39).
15. Grinder according to claim 14, characterised in that the torsion spring (39) is a helical torsion spring fitted around the hinged axis (22) between one of the bearing arms (26) of the pivoting element (21) and the bearing projection (28) of the handle end-section (3) assigned to it, and resting on the latter.
16. Grinder according to any of claims 1 to 15, characterised in that the grinding wheel head (2) is mounted so as to be pivotable relative to the handle end-section (3) around two pivot axes (8, 9) arranged at right-angles to each other.
17. Grinder according to any of claims 1 to 16, characterised in that at least one of the end areas of the suction hose (15) is connected rotatably to the extraction hood (14) or the handle end-section (3) in such a way that, in the respectively set rotary position, the end area concerned is held or may be fixed automatically.

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