Hand grinder for grinding wall surfaces at corners between two walls

Abstract

The invention relates to a hand grinder for grinding wall surfaces at corners between two walls, comprising two plates, which have two adjoining edges and in each case a planar front side for applying a grinding disk, a joint, via which the two plates are connected for pivoting about an axis running along the two adjoining edges, a fixing device for fixing the two plates in a set pivoting position, and a handle which is arranged on the rear side of the two plates and is connected thereto in order to displace the two plates along the surfaces to be ground.

Description

[0001] Hand sander for sanding wall surfaces at corners between two walls

[0002] The invention relates to a hand sander for sanding wall surfaces at corners between two walls.

[0003] Hand sanders are sanding tools used to smooth plasterboard or interior plaster to prepare it for the application of interior paint, wallpaper, or other wall coverings. For sanding the interior surfaces of walls or ceilings, hand sanders consist of a board with a flat front and a handle on the back. Sandpaper (e.g., a sanding disc) is attached to the front, folded over at the outer edges of the board, and secured to the back using hook-and-loop fasteners or clamps.

[0004] Furthermore, long-reach sanders (also called "Giraffe" - a registered trademark of the company Flex) are known, which have a telescopic arm with a disc-shaped working head at the front end and a handle at the rear. The working head includes a drive motor and a sanding disc on one side and is mounted on a swiveling bearing to adapt to the wall surface being sanded.

[0005] One problem when sanding plaster and drywall surfaces is the corners between a knee wall (or a sloping wall) and a roof slope, between a roof slope and an intermediate floor, and between two roof slopes in the gable area.

[0006] Using a hand sander or long-reach sander, you must work on the corners from different sides. Working from different sides can lead to uneven smoothing of the interior wall surfaces in the corner area.

[0007] Hand sanders with a 90° angled pad (also known as "90° inside corner sanders") are already familiar. While these hand sanders facilitate the even smoothing of wall surfaces, they are only suitable for inside corners with a 90° angle. However, the angles between roof slopes and adjacent walls deviate from a right angle and can vary considerably from house to house.

[0008] Based on this, the invention aims to provide a grinding device that facilitates the uniform smoothing of wall surfaces at corners between two walls, regardless of the angle between the wall surfaces.

[0009] The problem is solved by a hand grinder according to claim 1. Advantageous embodiments of the hand grinder according to the invention are specified in the dependent claims and in the description.

[0010] The hand sander according to the invention for sanding wall surfaces at corners between two walls comprises

[0011] • two plates, each having two adjacent edges and a flat front surface for mounting a grinding wheel,

[0012] • a joint by which the two plates are pivotably connected about an axis running along the two adjacent edges,

[0013] • a locking device for locking the two plates in a set swivel position and • a handle located on the back of the two plates and connected to them, to move the two plates along the surfaces to be sanded.

[0014] The hand sander according to the invention has two plates connected to each other via a joint with adjustable angular alignment to adapt to the respective angle of a corner between two walls. The hand sander also has a locking device to fix a set pivot position of the two plates, preventing them from changing during the processing of a corner area. Advantageously, the hand sander can be adjusted to any desired corner angle, allowing it to be used for smoothing wall areas at variable corners between a roof slope and a knee wall (or a soffit wall), an intermediate floor, or another roof slope (collectively referred to as an "adjacent wall"). The hand sander can also be used for smoothing wall areas at 90° corners between two walls or between a wall and a ceiling.By precisely aligning the plates of the hand sander according to the invention to the respective angle, a uniform smoothing of the wall surfaces in the corner area can be easily achieved by placing the hand sander at the corner and moving it along the corner. Adjusting the hand sander to the respective angle can be done quickly and easily. The hand sander can be designed to be suitable for use on corners with significantly different angles. The adjustable angle can be set, in particular, within a range from above 90° to 90° and, if necessary, down to below 90°.

[0015] According to one embodiment of the invention, the joint has at least one pair of curved guides, each with a curved elongated hole, wherein one curved guide of the pair is fixed to the back of one plate and the other

[0016] .. / 4 The curved guide of the pair is firmly connected to the back of the other plate, the centers of the radii of curvature of the curved slots of the two curved guides fall into the adjacent edges of the two plates, an axle is inserted through the two curved slots, which is connected at both ends to projections that can be clamped to the outer surfaces of the two curved guides via a clamping device in order to lock them in the set pivot position. In this design, the locking device is integrated into the joint, since the axis of the joint is also used to clamp the two curved guides in the set pivot position by means of the clamping device.

[0017] In an alternative design, the locking device is separate from the joint. For example, the locking device could be a threaded clamp connected to the two plates at its ends.

[0018] The joint can also be designed in ways other than by means of two curved guides. For example, as with a rod hinge or a band hinge, the joint can be formed directly at the adjoining edges of the two plates. In this case, the hand slider may be slightly wider at the adjoining edges of the two plates than with a joint design using curved guides, where the adjoining edges do not form a joint.

[0019] In another embodiment, the joint has two pairs of curved guides, with the two pairs connected to the two plates at a distance from each other, and the axis extending through the curved elongated holes of the two pairs. This results in a particularly stable joint that can hold the plates precisely in the set pivot position. Furthermore, this embodiment allows the axis between the two pairs of curved guides to be gripped and used as a handle.

[0020] In another embodiment, the curved guides are each formed by an arc segment that has a curved elongated hole and is rigidly connected at one end to one of the two plates. This results in a particularly simple design.

[0021] In another embodiment, each plate is integrally connected to each associated curved section. This is advantageous for the production, assembly, and strength of the hand grinder.

[0022] According to another embodiment, the clamping device comprises a rod arranged between the two pairs of cam guides, at the ends of which the opposing cam guides of the two pairs bear against each other, threaded bolts protruding from both ends of the rod, each of which is inserted through the elongated holes of the two cam guides of one pair, and screw heads firmly connected to the threaded bolts or nuts screwed onto the threaded bolts, which bear against the opposing cam guides of the two pairs. By tightening the screw heads or nuts, the two cam guides of the pairs can be clamped together, so that the pivot joint is clamped in the set pivot position. If the threaded bolts are firmly connected to screw heads, the rod has internal threads into which the threaded bolts can be screwed.When nuts are screwed onto the threaded bolts, the threaded bolts are firmly connected to the ends of the rod.

[0023] ...16 According to one embodiment, each threaded bolt is inserted through a central through-hole of an adjusting washer, which has a hexagonal recess on one end face with its center on the middle of the through-hole. The through-hole and the recess are designed such that the threaded bolt can be inserted through the through-hole and the bolt head or nut can be positively engaged in the recess, so that the bolt head or nut can be adjusted by turning the adjusting washer. The adjusting washer, which has a larger diameter than the bolt head or nut, facilitates the manual tightening and loosening of the joint. According to another embodiment, the adjusting washer has knurling on its outer circumference, which facilitates turning the adjusting washer by hand.

[0024] In another design, a handle projects radially outwards from the rod. The handle can be positioned between the plates as needed. This radially projecting handle allows for a particularly secure grip on the hand sander and enables the necessary pressure to be applied across the surfaces to be sanded.

[0025] The handle can also be designed separately from the joint. For example, a bow handle can be permanently attached to only one of the two plates.

[0026] In another version, the plates have chamfers on the back sides at the adjacent edges. These chamfers create sharp edges, allowing the two plates to be pivoted tightly around their adjacent edges. This enables particularly precise sanding of the corners. In yet another version, the plates have further chamfers on the back sides at the edges facing away from each other. These additional chamfers facilitate wrapping the edges of sandpaper around the opposite edges of the plates and securing the sandpaper to the back sides.

[0027] In another design, the adjacent edges of the two plates are longer than the edges facing away from each other. This allows the hand sander, when placed against a corner with its adjacent edges, to be positioned closer to the corner ends.

[0028] According to another design, the side edges of the two plates are beveled or curved, which further facilitates pushing them towards the ends of the corners.

[0029] In another embodiment, the two plates each have a hook-and-loop fastener on their backs for forming a hook-and-loop connection with a strip of sandpaper, which can be attached to the fronts of the two plates and folded around the edges of the plates facing away from each other. Alternatively, instead of hook-and-loop fasteners, the two plates have clips on their backs for fixing the edges of the sandpaper folded around the edges of the plates.

[0030] According to another embodiment, the hand grinder consists of plastic and / or metal.

[0031] ,.. / 8 The invention is explained in more detail below with reference to the accompanying drawings of exemplary embodiments. The drawings show:

[0032] Fig. 1 shows a hand grinder according to the invention in a perspective view of the front;

[0033] Fig. 2 shows the same hand grinder in a perspective view of the back;

[0034] Fig. 3 shows the two plates of the same hand grinder in a perspective view of the back;

[0035] Fig. 4a-c Rod with handle of the same hand grinder in a front view (Fig. 4a), in a bottom view (Fig. 4b) and in a side view (Fig. 4c);

[0036] Fig. 5a, b Adjustment disc of the same hand grinder in a front view (Fig. 5a) and in a top view (Fig. 5b);

[0037] Fig. 6 shows the two plates of a second embodiment of the inventive hand grinder in a perspective view of the back.

[0038] According to Figs. 1 and 2, a hand grinder 1 has two plates 3, 4 aligned at an angle 2 to each other, which have two adjacent edges 5, 6 and each a flat front surface 7, 8.

[0039] The two plates 3, 4 are pivotally connected to each other via a joint 9. The axis 10 of the joint 9, about which the two plates 3, 4 can pivot, runs along the two adjacent edges 5, 6 of the two plates 3, 4.

[0040] Furthermore, a locking device 11 is provided, which serves to lock the two plates 3, 4 in their respective set pivot positions.

[0041] ...19 Finally, the hand sander 1 has a handle 12, which is arranged on and connected to the backs 13, 14 of the two plates 3, 4. The handle 12 serves to move the two plates 3, 4, which are set in a specific pivot position, along the surfaces to be sanded at a corner of a room.

[0042] As can be seen more clearly in Fig. 3, the joint 9 has two pairs 15, 16 curved guides 17, 18, 19, 20, the two pairs of curved guides being connected to the two plates 3, 4 at a distance from each other. Each curved guide 17, 18, 19, 20 has a curved slot 21, 22, 23, 24, the centers of the radii of curvature of the curved slots of the two curved guides falling on the adjacent edges 5, 6 of the two plates 3, 4.

[0043] The curved guides 17, 18, 19, 20 are each formed by an arc segment 25, 26, 27, 28, which has the curved elongated slot 21, 22, 23, 24 and is rigidly connected at one end to one of the two plates 3, 4. The adjacent edges 5, 6 of the two plates 3, 4 are longer than the opposite edges 29, 30 of the two plates 3, 4. The lateral edges 31, 32 of the two plates 3, 4 are curved in an arc.

[0044] The arc pieces 26, 27 on the plate 4 are closer to each other than the arc pieces 25, 28 on the plate 3, so that the first-mentioned plate 4 with its arc pieces 26, 27 can be pivoted between the arc pieces 25, 28 of the second-mentioned plate 3.

[0045] The adjacent edges 5, 6 have a chamfer 33, 34 on the back 13, 14 of the plates 3, 4, so that these edges 5, 6 are shaped like cutting edges. On the opposite edges 29, 30, the plates 3, 4 have a further chamfer 35, 36 on their reverse sides 13, 14, so that these edges 29, 30 are also shaped like cutting edges. Hook and loop fastener strips 37, 38 of a hook and loop fastener 39 are glued to the opposite edges 29, 30 on the reverse sides 13, 14 of the two plates 3, 4.

[0046] As shown in Fig. 4, the eyelet-shaped handle 12 is connected radially to a cylindrical rod 41 via a lateral web 40. The rod 41 has bore holes 42, 43 at both ends, in which internal threads 44, 45 are arranged.

[0047] As shown in Figures 1 and 2, the two plates 3, 4 are pivoted slightly together about the axis 10, which runs along their adjacent edges 5, 6, so that the curved sections 27, 28 of one plate 4 engage between the curved sections 25, 26 of the other plate 3 and the curved slots 21, 22 and 22, 24 partially overlap each other. The rod 41 is positioned between the two inner curved sections 27, 28, so that the boreholes 42, 43 at its two ends are aligned with the slots 21, 22, 23, 24. Screws 46, 47 are inserted with their screw bolts 48, 49 from the outside of the arc pieces 25, 26 through the overlapping sections of the elongated holes 21, 22, 23, 24 and screwed into the internal threads 44, 45 in the boreholes 42, 43.

[0048] To facilitate clamping the arc pieces 25, 26, 27, 28, the screws 46, 47 have adjusting washers 50, 51 at their ends with knurling 52, 53 on their outer circumference (see Fig. 5). The screws 46, 47 are inserted with their bolts 48, 49 through central bores 54, 55 of the adjusting washers 50, 51 and their screw heads 55, 56 engage positively in hexagonal recesses 57, 58 on the end faces of the adjusting washers 50, 51. By tightening the Screws 46, 47 clamp the overlapping arc pieces 25, 26, 27, 28 between the rod 41 and the screw heads 55, 56, thereby fixing the hand grinder 1 in the set pivot position of the two plates 3, 4.

[0049] Sandpaper (e.g., a sanding disc) is applied to the front surfaces 7, 8 of the two plates 3, 4 and its edges are wrapped around the opposite edges 29, 30 of the two plates 3, 4. The wrapped ends of the sandpaper have hook-and-loop fasteners that are connected to the hook-and-loop fasteners 37, 38 on the back surfaces 13, 14 of the two plates 3, 4 to secure the sandpaper to the plates 3, 4.

[0050] Afterwards, the hand sander 1 can be used for sanding in the area of ​​a corner between two walls, to which the angle between the two plates 3, 4 is set.

[0051] To change the pivot position of the two plates 3, 4, the two screws 46, 47 can be loosened, the plates 3, 4 readjusted and then the set pivot position secured again by tightening the screws 46, 47.

[0052] The hand sander 1 described above allows the angle between plates 3 and 4 to be adjusted within a range of 120° to 85°. With respect to the front surfaces of plates 3 and 4, this corresponds to an angle range of 240° to 275°. This hand sander 1 can be used in particular for sanding corners between a sloping roof and a knee wall or intermediate floor, or between two walls at a 90° angle. The plates 3, 4 according to Fig. 6 differ from the plates of the previously described hand grinder 1 in that the arc sections 25, 26, 27, 28 are shorter. Consequently, the two plates 3, 4 are pivoted closer together around the adjacent edges 5, 6 when the elongated holes 21, 22, 23, 24 in the arc sections 25, 26, 27, 28 of the different plates 3, 4 overlap.

[0053] The plates 3, 4 according to Fig. 6 can be used with the same rod 41 with handle 12 and with the same screws 46, 47 and adjusting washers 50, 51 as the plates 3, 4 according to Fig. 3. In this embodiment, the plates 3, 4 can be pivoted relative to each other in a range of 85° to 60°, which corresponds to an angle between the front faces of the plates 3, 4 of 275° to 300°. This hand sander can be used in particular for sanding corners in the gable area between adjacent roof slopes. Reference list Hand sander Angle, 4 Plate, 6 Edge, 8 Flat front Joint 0 Axis 1 Locking device 2 Handle 3, 14 Back 5, 16 Two pairs 7-20 Curved guide 1-24 Slotted hole 5-28 Arc piece 9, 30 Edges 1, 32 Side edge 3, 34 Chamfer 5, 36 Chamfer 7, 38 Hook and loop strip 9 Hook and loop fastener 0 Side bar 1 Rod 2, 43 Borehole 4, 45 Internal thread 6, 47 Screw 8, 49 Screw bolt

[0054] ,.. / 14 , 51 Adjustment disc , 53 Grooving , 55 Central bore , 56 Screw head , 58 Recess , 60 Hook and loop strip

Claims

Claims:

1. Hand sander for sanding wall surfaces at corners between two walls, including • two plates, each having two adjacent edges and a flat front surface for mounting a grinding wheel, • a joint by which the two plates are pivotably connected about an axis running along the two adjacent edges, • a locking device for locking the two plates in a set swivel position and • a handle located on the back of the two plates and connected to them, to move the two plates along the surfaces to be sanded.

2. Hand grinder according to claim 1, wherein the joint has at least one pair of curved guides, each with a curved elongated hole, wherein one curved guide of the pair is fixedly connected to the back of one plate and the other curved guide of the pair is fixedly connected to the back of the other plate, the centers of the radii of curvature of the curved elongated holes of the two curved guides fall into the adjacent edges of the two plates, and an axle is inserted through the two curved elongated holes, the axle being connected at both ends to projections which can be clamped to the outer surfaces of the two curved guides via a clamping device in order to clamp them in the set pivot position.

3. Hand grinder according to claim 2, wherein the joint has two pairs of curved guides, the two pairs being connected to the two plates at a distance from each other and the axis extending through the curved elongated holes of both pairs.

4. Hand grinder according to claim 2 or 3, wherein the curve guides are each formed by an arc piece having a curved elongated hole and being connected at one end to one of the two plates.

5. Hand grinder according to one of claims 2 to 4, wherein each plate is integrally connected to each associated curved guide.

6. Hand grinder according to one of claims 2 to 5, wherein the clamping device comprises the following features: A clamping device between the two pairs A rod arranged in curve guides, at the ends of which the opposing curve guides of the two pairs rest, threaded bolts protruding from the two ends of the rod, each of which is inserted through the elongated holes of the two curve guides of a pair, and screw heads connected to the threaded bolts or nuts screwed onto the threaded bolts, which rest against the opposing curve guides of the two pairs.

7. Hand grinder according to claim 6, in which each threaded bolt is inserted through a central through-hole of an adjusting washer, which has on one end face a hexagonal recess with its center on the middle of the through-hole, which is designed to be complementary to the screw head or nut, such that the recess is aligned with the inserted The screw head or the inserted nut forms a positive locking connection.

8. Hand grinder according to claim 7, wherein the discs have a knurling on the outer circumference.

9. Hand grinder according to one of claims 6 to 8, wherein a handle projects radially outwards from the rod.

10. Hand grinder according to one of claims 1 to 9, wherein the two plates have chamfers on the back sides at the adjoining edges.

11. Hand grinder according to one of claims 1 to 10, wherein the plates have further chamfers on the rear sides at the edges facing away from each other.

12. Hand grinder according to one of claims 1 to 11, wherein the adjacent edges of the two plates are longer than the edges of the two plates facing away from each other.

13. Hand grinder according to one of claims 1 to 12, wherein the side edges of the two plates are beveled or curved.

14. Hand sander according to one of claims 1 to 13, wherein the two plates each have a hook and loop fastener on their back sides for forming a hook and loop connection with a hook and loop fastener on a sanding disc, which can be applied to the front sides of the two plates and folded around the edges of the two plates facing away from each other.

15. Hand grinder of any one of claims 1 to 14, made of plastic and / or metal.

Images