WO2008131748A2 - Portable grinder - Google Patents

Abstract

The invention relates to a portable grinder comprising a grinding head (5) that can be placed against a workpiece (7) in a grinding contact zone (26). According to the invention, a stop (18-21) is disposed at a distance from the grinding contact zone (26). Said stop (18-21) forms an axis of rotation (27) as a swiveling axis for the grinding head (5) and as a pivot relative to at least one handle (2, 3).

Description

 Description:

"Hαndschleifmαschine"

The invention relates to a vertical grinding machine with a grinding head which can be attached to a workpiece in a sliding contact area.

From WO 2005/095052 AI, such hand grinder machines are known, which allow the machine to be arranged in at least one spatial direction in a manner that is stable against tilting against a workpiece. Described is u.a. a grinding machine with a conical grinding head for grinding edges. The machine can be pressed against a workpiece surface which is adjacent to the edge by means of a ring plate concentrically surrounding the grinding head. The hand grinder allows high removal rates. On the other hand, the degrees of freedom for the grinding head movement are limited. In addition, angle grinders are known with unrestricted in its position changeable grinding head.

The invention has for its object to provide a new hand grinder, which combines higher flexibility of the grinding head movement with high removal rate and grinding quality.

The object-solving hand grinder according to the invention is characterized by a arranged at a distance from the sliding contact area stop which forms an axis of rotation as a pivot axis for the grinding head and as a lever rotation axis with respect to at least one handle when abutting against the workpiece. Advantageously, the angular position of the grinding head with respect to the direction of the pivot axis is largely determined by the stop arranged at a distance from the sliding contact region. Changes in this angular position are possible only within the framework of the grinding head infeed, which is approximately vertical to the workpiece surface. The user of the grinding machine can therefore, without tilting the grinding head in the said one direction, ie with high grinding accuracy, a large grinding pressure force and parallel to the workpiece surface exert a large feed force.

In the preferred embodiment, two spaced-apart handles for holding and guiding the machine are provided with both hands, wherein, in projection on the workpiece, the grinding head and / or the stop are arranged between the handles or is.

Preferably, the stopper is designed such that the machine can also be pressed against tilting against the workpiece in the direction of the pivot axis. Thus, the user can concentrate even more on the exercise of appropriate Schleifandruck- and feed forces.

Preferably, the stop is rounded in a plane perpendicular to the pivot axis cutting plane. He can e.g. be formed by a circular cross-section bolt.

In a particularly preferred embodiment of the invention, the stop comprises an insertable against the workpiece role, wherein a plurality of spaced-apart rollers may be provided. Preferably, the distance between the rollers is adjustable.

The rollers may be lockable on a shaft or rotatable on an axis. Preferably, the rollers can be locked at a desired distance from each other on the shaft.

In a further embodiment of the invention, two rollers on opposite sides each have an oblique rolling surface for abutment of the guide stop on workpiece surfaces which are angled at an angle. Such a guide stop with 45 ° beveled rolling surfaces can be applied, for example, to mutually perpendicular surfaces of a workpiece in order to grind a bevel on the edge formed by the meeting surfaces of 45 °. The rolling surfaces can be chamfered differently, for example by 30 ° and the other by 60 °. Then there is a chamfer angle of 30 °.

While as a grinding head e.g. a belt grinding head is contemplated, it is in the preferred embodiment of the invention is a rotating grinding head, wherein the pivot axis formed by the guide stop extends in a tangential direction to the axis of rotation of the grinding head.

Preferably, the pivot axis formed by the guide stop extends parallel to a ground surface through the grinding head.

Preferably, the guide stop is pivotable against the axis of rotation of the grinding head and can be locked in a desired position. The position can be adjusted according to the inclination on a grinding wheel frontally mounted oblique annular grinding surfaces.

In the preferred embodiment of the invention, the machine comprises an elongate housing surrounding a drive motor for the grinding head, the housing preferably projecting at an angle from a drive shaft for the grinding head.

At a distance from the pivot axis, in particular at the longitudinal ends of the housing, in each case a handle can be arranged through which a lever axis large lever length results, which allows to exert large pressure forces on the workpiece and thus also large grinding pressure forces. Suitably, the grinding head near the handle extends in its length parallel to the pivot axis.

In a particularly preferred embodiment, the guide device is part of a grinding unit comprehensive, can be coupled to the housing assembly. Thus, e.g. the housing of a commercial angle grinder used and the angle grinder be converted to device according to the invention.

In one embodiment of the invention, the grinding head has a flap grinding wheel, in particular with a wire plate underlay, in order to be able to absorb higher pressure forces. Appropriately, such grinding machines, for example, by a hexagonal socket, secured against the use of normal grinding heads. The invention will be explained in more detail with reference to embodiments and the accompanying drawings relating to these embodiments. Show it:

1 shows a first embodiment of a hand grinder according to the invention in a perspective view, Figure 2, the hand grinder of Fig. 1 in a to the view of Fig. 1 to

3 shows a detail of the hand grinding machine of FIG. 1, FIG. 4 shows a perspective exploded view of the hand grinding machine of FIG. 1, which comprises an assembly which can be coupled to a commercial angle grinder,

5 is a detail view of the assembly of Figure 4 in a sectional side view, Fig. 6 is a partial perspective view of the assembly of Figure 4, and

7 to 9 another embodiment of a hand grinder according to the invention in various perspective intentions.

A hand grinder has an elongate housing 1 with a handle 2 at one end and a handle 3 formed as a bracket at the opposite end.

From the housing 1 there projects laterally a drive shaft 4 (FIG. 4) which is in driving connection with a motor / gear assembly (not shown) accommodated in the housing 1.

The drive shaft 4 drives a grinding head 5 with a grinding wheel 6. The grinding wheel 6 has, on its side facing a workpiece 7, an annular surface 8 (FIG. 3) inclined to the disk plane, which is in sliding contact with the workpiece 7.

The grinding head 5 is part of a separately shown in Fig. 4 illustrated assembly 9, which comprises a cylindrical connector 10 for clamping connection with a lug 1 1 on the housing 1. With the production of the clamping connection, the drive shaft 4 is brought into drive connection with the grinding head 5. The cylindrical connector 10 of the assembly 9 is attached to a U-shaped holding part 12 with U-legs 13 and 14. At the U-legs a U-shaped sheet metal part 15 is hinged via screw. At a distance from the screw connections, in each case a further screw connection is provided, with bolts each passing through a slot 16 in the U leg of the sheet metal part 15. On one side of the U-shaped sheet metal part 15, a spark arrester 22 is screwed.

Between the U-legs of the sheet metal part 15, the base leg has a preferably covered with Plexiglas opening 17, a rotatably supported by shaft bearings 21 on the U-legs shaft 18 on the two by clamping screws rotatably connected to the shaft rollers 19 and 20 sit , Instead of the shaft, a rigidly connected to the U-shaped plate member 15 axle bolts could be provided on which the rollers can rotate independently.

As is apparent from FIGS. 5 and 6, a rotatable member 26, which can be connected to the grinding wheel 6, of the grinding head 5 is rotatably mounted in a bushing part 28 via a ball bearing 27. The female part 28 is coupled to the connector 10. The drive shaft 4 engages in a bore 29 in the rotary member 26, wherein a coupling 30 produces a drive connection to the rotary member 26.

For grinding the flat surface of the workpiece 7, for example for grinding a protruding weld seam 23 (FIG. 2), the grinding machine is pressed by means of both handles 2 and 3 in a sliding contact region 26 and via the rollers 19, 20 to the workpiece 7, wherein in particular by suitable distribution of the load a desired grinding pressure or feed is generated both perpendicular to the workpiece surface and in the longitudinal direction of the weld 23. The axis of rotation of the shaft 18 forms a lever rotation axis for the handles and a pivot axis 27 for the grinding head 5. The distance of the axis to the handle 2 is about 300 mm, the handle 3 about 150 mm. When feeding along the weld 23, the rollers or wheels 19 and 20 roll on the workpiece surface. Due to the distance between the rollers, which is adjustable, the grinding machine can not tilt in the direction of the axis of rotation of the shaft 18, ie perpendicular to the feed direction. The grinding machine sits on the surface of the workpiece 7 corresponding to a three-point bearing. The guide through the shaft 18 with the rollers 19 and 20 allows the user of the grinder to fully enjoy himself focus on exercising the right pressure and feed forces. Furthermore, the rollers 19 and 20, which are fixed against rotation on the shaft 18, facilitate the straight-line guidance of the grinding machine along the weld seam 23.

Instead of the rollers between which the weld lies, a shaft with a suitable profiling could also be used.

In the embodiment of Figs. 5-7 identical or equivalent parts are designated by the same reference number as in the preceding embodiment, the relevant reference number is attached to the letter a.

The exemplary embodiment according to FIGS. 5-7 differs from the preceding exemplary embodiment in that, on a shaft 18a, rollers 19a and 20a, which are seated against rotation relative to one another, have an annular surface 24 or 25 inclined by 45 ° relative to the shaft axis.

The hand grinder according to FIGS. 5-7 is therefore attachable to mutually perpendicular surfaces of a workpiece 7a and thus can be used as a bevel grinding machine. The machine can not tilt perpendicular to the chamfer longitudinal direction. The grinding flat chamfers is thereby additionally facilitated.

The assembly 9 or 9a of the bevel grinding machine described above can be locked to the rotation axis of the grinding head 5 in desired positions, this position being dependent on the inclination of the annular surface 8 on the grinding wheel 7. The setting is made so that the surface line of the annular surface 8 in the feed direction in each case runs parallel to the workpiece surface.

In certain applications, it may be advantageous to place only an axis or shaft directly on an edge. The shaft can be profiled so that it does not slip sideways. The roles can be moved in such cases completely outward and arrest there.

Claims

claims: 1. Hand grinder with a in a sliding contact region (26) to a Workpiece (7) attachable grinding head (5), characterized by a spaced from the sliding contact region (26) arranged stop (18-21), which upon contact against the workpiece (7) has a rotation axis (27) as a pivot axis for the grinding head ( 5) and forms as a lever rotation axis with respect to at least one handle (2,3). 2. Hand grinder according to claim 1, characterized in that two spaced-apart handles (2,3) are provided for holding and guiding the machine with both hands. 3. Hand grinder according to claim 2, characterized in that, in projection on the workpiece, the grinding head (5) and / or the stop (18-21) between the handles (2,3) are arranged or is. 4. Hand grinder according to one of claims 1 to 3, characterized in that the stop is a guide stop (18-21), a in the direction of Swivel axis tilt-stable pressing the machine to the workpiece (7) allows. 5. Hand grinder according to one of claims 1 to 4, characterized in that the stop (18-21) is rounded at least on its the workpiece (7) facing side in a plane perpendicular to the pivot axis cutting plane. 6. Hand grinder according to one of claims 1 to 5, characterized in that the stop (18-21) against the workpiece (7) can be applied roller (19,20). 7. Hαndschleifmαschine according to claim 6, characterized in that a plurality of spaced-apart rollers (19,20) are provided. 8. hand grinder according to claim 7, characterized in that the distance between the rollers (19,20) is adjustable. 9. hand grinder according to claim 7 or 8, characterized in that the rollers (19,20) on a shaft (18) are lockable or rotatable on an axis. 10. Hand grinding machine according to one of claims 7 to 9, characterized in that two rollers (19,20) on opposite sides of an inclined rolling surface (24,25) for abutment of the guide stop on each other at an angle workpiece surfaces. 11. Hand grinder according to one of claims 1 to 10, characterized in that extending through the stop (18-21) formed pivot axis in a tangential direction to a rotation axis of the grinding head (5). 12. Hand grinder according to one of claims 1 to 1 1, characterized in that extending through the stop (18-21) formed pivot axis parallel to a ground by the grinding head (5) surface. 13. Hand grinder according to claim 1 1 or 12, characterized in that the stop (18-21) against the axis of rotation of the grinding head (5) is pivotable and lockable in a desired pivot position. 14. Hand grinder according to one of claims 1 to 13, characterized in that the machine has an elongate housing (1) surrounding the drive motor for the grinding head (5), a drive shaft (4) projecting from the housing (1), preferably at an angle, for the grinding head (5). 15. Hand grinder according to claim 14, characterized in that the stop is part of a grinding head (5) comprehensive, to the housing (1) coupled to the unit (9). 16. Hand grinder according to one of claims 1 to 15, characterized in that the grinding head near the handle (3) preferably extends in its length parallel to the pivot axis. 17. Hand grinder according to one of claims 1 to 16, characterized in that the grinding head a flap grinding wheel, preferably with a steel plate base comprises. 18. Hand grinding machine according to one of claims 15 to 17, characterized in that the structural unit (9) comprises a socket part (28), in which the grinding head (5) is rotatably mounted.