GB2402641A - A sanding plate for a motor driven hand-held sanding tool - Google Patents

Abstract

A sanding plate 4 for a motor driven hand held sanding tool comprises two sanding regions 1 and 2 and an interconnecting region 3 there between. The two sanding regions 1 and 2 are identically configured and are arranged symmetrically to one another with respect to an axis of symmetry S running through the connecting region 3. The sanding regions 1 and 2 are preferably both equilateral triangular in shape with outwardly curving edges (delta sanding surfaces), with the edge of one region 13 facing the edge of the other 23. Each sanding region 1 and 2 comprises a plurality of dust extraction openings 17 and 27 arranged in a circle. Dust extraction openings 31 are also located at the external edges of the interconnecting region 3.

Description

SANDING PLATE FOR A MOTOR-DRIVEN HAND-HELD SANDING TOOL

The invention takes as its starting point a sanding plate for a motordriven hand-held sanding tool, having the generic features of Claim 1.

Hand-held sanding machines which have sanding plates of rectangular shape with a 1/2, l/3 or 1/4 sheet are known. Moreover, such rectangular sanding plates of x 133 mm size are known. Although these hand-held sanding machines allow very good sanding of surfaces, they are suitable only to a limited degree for corner or edge sanding.

To sand corners or edges, so-called delta sanders, which have a sanding plate with an equilateral, triangular base area and arcuately outwardly curved outer sides, are known.

The corner regions thereby formed allow very good corner sanding to be achieved and the arcuately outwardly curved outer sides also enable very good edge sanding.

However, these delta sanders are not suitable for surface sanding, since they only have a small sanding area and the sanding sheet quickly becomes clogged with sanding dust when sanding larger surfaces.

To achieve not only good corner and edge sanding but also good surface sanding, hand-held sanding machines whose sanding plates have the shape of a smoothing iron are known. At the tip of the smoothing iron good corner sanding is possible, in the region of the lateral edges good edge sanding can be effected and owing to the large sanding area adequate surface sanding can be effected, without the sanding sheet quickly becoming clogged with sanding dust. The problem with such smoothing-iron- shaped hand-held sanding machines, however, lies in the fact that the sanding sheet becomes completely unusable in the event of partial wear, which occurs regularly especially at the front corner or the edges, and thus has to be disposed of. This results in both high costs for the user of the hand-held sanding machine and a high ecological load.

A sanding plate according to the invention for a motor-driven hand-held sanding tool, having the features of Claim 1, has, in contrast, the advantage that two identical sanding sheets can be used for the two identically equipped sanding regions. When the sanding sheet arranged at the front tip shows signs of wear, the two sanding sheets can be exchanged between the first sanding region and the second sanding region. Compared with a known sanding plate in the shape of a smoothing iron with a sanding area of equal size, twice as long a service life can thereby be achieved.

The sanding plate is preferably designed such that both the first sanding region and the second sanding region each has an equilateral, triangular base area with arcuately outwardly curved edges. Consequently, an even longer service life of the sanding sheets is achieved, since the first sanding sheet, which is arranged on the first sanding region, can be rotated twice through 120 if the wear occurs at the tip of the sanding plate. Since the second sanding sheet, which is arranged on the second sanding region, serves merely for surface sanding, hardly any wear at all occurs thereon. Thus, even if the first sanding sheet has signs of wear at its three corners, the first sanding sheet can be exchanged with the second sanding sheet. The second sanding sheet can then be rotated twice through 120 , analogously to the first sanding sheet, if the front corner shows signs of wear.

The sanding plate is preferably designed such that both the first sanding region and the second sanding region each have a plurality of extraction openings, which are in each case arranged in particular on a circle. It is thereby avoided that neither the first sanding sheet on the first sanding region nor the second sanding sheet on the second sanding region becomes clogged with sanding dust. By this means, too, the service life is again considerably increased.

The sanding plate is preferably designed such that a plurality of extraction ducts are formed in the connecting region. This leads to a further increase in the service life, since even more sanding dust, in particular from the region of the sanding plate, is extracted and the two sanding sheets therefore become clogged even more slowly with sanding dust than they would without these extraction ducts.

Further advantageous refinements of the invention are provided in the subclaims.

An exemplary embodiment of the invention is explained in more detai] in the following description with reference to the associated drawings: Figure 1 shows a schematic plan view of a sanding plate according to the invention; Figure 2 shows a vertical section through the sanding plate from Figure 1 along the line A-A with a sanding sheet attached; and Figure 3 shows the plan view of a sanding sheet.

A schematic plan view of a sanding plate 4 according to the invention is illustrated in Figure 1. The two sanding sheets 8 (see Figures 2 and 3) are attached to the illustrated surface, when the sanding plate is used on a motor-driven hand-held sanding tool (not shown). The sanding plate 4 is connected to the motor- driven hand- held sanding tool (not shown) via connecting means (not illustrated). However, since this connection does not form part of the subject-matter of the invention and is known to the expert from the prior art, it is not illustrated nor is it described in more detail hereinbelow.

The sanding plate 4 has three regions, which are easily distinguishable from one another. Formed at the top is a first sanding region l, which is connected via a connecting region 3 to a second sanding region 2 at the lower end of the sanding plate 1. The two sanding regions 1, 2 are identically equipped and each arranged symmetrically to a longitudinal axis L, so that only the configuration of the first sanding region 1 is described hereinbelow.

The first sanding region l has an equilateral, triangular base area. This base area is bounded by three arcuately outwardly curved edges 11, 12, 13. The three corners 14, 15, 16 enclosed by the three edges] l, 12, 13 each have an angle of about 90 . It goes without saying that, with other radii of curvature of the three edges 11, 12, 13, other angles for the three corner regions 14, 15, 16 can be obtained.

The first sanding region 1 is arranged in such a way with respect to the longitudinal axis L that its first corner 14 points upwards. In the installed state, this first corner 14 forms the tip of the hand-held sanding tool. Formed in the first sanding region 1 are a total of six extraction openings 17, which lie on a common circle about the centre of the base area. Besides this configuration with six extraction openings 17, any other number of extraction openings 17 is also possible, and they may also be arranged in any geometrical patterns within the first sanding region 1.

The second sanding region 2, which is configured identically to the first sanding region l, is arranged symmetrically to an axis of symmetry S. The axis of symmetry S runs through the connecting region 3 and is perpendicular to the longitudinal axis L. Consequently, the third edge 13 of the first sanding region and the third edge 23 of the second sanding region lie mutually opposite. The first corner 24 of the second sanding region 2 thus forms the rear end of the sanding plate 4 in the installed state.

The first sanding region l thus serves, in the region of the first corner 14, for sanding corners and, in the region of its first edge 11 and second edge 12, for sanding edges.

In contrast, the second sanding region 2 serves for sanding surfaces. In the connecting region 3, a total of four extraction ducts 31 are arranged both symmetrically to the longitudinal axis L and to the axis of symmetry S. These four extraction ducts 31 are arranged in the border region of the sanding plate 4. It goes without saying that, besides the specifically illustrated form of the extraction ducts, both in terms of geometry and number, any other possible configurations of these extraction ducts 31 are also possible.

Both the extraction ducts 31 and the extraction openings 17, 27 serve for extracting sanding dust which is abraded by the sanding sheets 8 (see Figures 2 and 3) during sanding operation and would otherwise clog the sanding sheets 8.

A vertical section through the second sanding region 2 is illustrated in Figure 2. The layered structure of the entire sanding plate 4 is clearly evident here. On the machine side there is arranged first of all a backing plate 5, which is formed from a torsionally rigid material, for example polyamide. The centring and locking devices (not shown) for connection to the hand-held sanding tool are injection-moulded on this backing plate. Adjoining the torsionally rigid backing plate 5 is a soft intermediate plate 6 made of polyurethane or cellular rubber. This plate is foamed on or adhesively bonded to the backing plate 5. Beneath the soft intermediate plate 6, a hook and loop fabric 7 is firmly connected to the soft intermediate plate 6. A sanding sheet 8 is attached to the hook and loop fabric 7. This sanding sheet 8 can be easily detached from the sanding plate 4 by simply pulling it off from the hook and loop fabric 7.

As shown in Figure 3, the sanding sheet 8 is identically constructed, in terms of its shape, to the two sanding regions 1 and 2. The sanding sheet 8 is therefore not described in detail hereinbelow, and you are referred instead to what was stated with regard to the first sanding region 1. As is clearly apparent from Figure 2, the sanding sheet 8 protrudes, however, by 1 - 2 mm beyond the outer contour of the respective sanding region 1, 2.

Consequently, the edges 81, 82, 83 of the sanding sheet 8 lie parallel to the respective edges 11, 12, 13; 21, 22, 23 of the respective sanding region 1; 2.

Furthermore, the corners 84, 85, 86 of the sanding sheet 8 each lie over the respective corners 14, 15, 16; 24, 25, 26 of the respective sanding regions 1; 2. The same applies to the extraction openings 87 of the sanding sheet 8 with respect to the respective extraction openings 17; 27 of the two sanding regions 1; 2.

During the operation of the hand-held sanding tool with the sanding plate 4 according to the invention and two sanding sheets 8 arranged thereon, the sanding sheet 8 which is arranged on the first sanding region 1 is subjected to particularly high stress in the region of its first corner 84. This applies particularly when sanding corners. Moreover, the first edge 81 and the second edge 82 of the sanding sheet 8 which is arranged on the first sanding region 1 are likewise subjected to relatively high stress, and this is so particularly when sanding edges. In contrast, the entire sanding sheet 8 which is arranged on the second sanding region 2 is hardly worn at all in this region, owing to the surface sanding. The same applies to the other regions of the sanding sheet 8 which is arranged on the first sanding region 1.

If the sanding sheet 8 which is arranged on the first sanding region 1 is worn in the region of its first corner 84, it can be simply pulled off from the hook and loop fabric 7, rotated through 120 and pressed onto the hook and loop fabric 7 again. In the case of clockwise rotation through 120 , the third corner 86 is thus arranged at the tip of the first sanding region 1. Now this third corner 86 is subjected to the highest stress.

As soon as this third corner 86 shows signs of wear, the procedure just described involving rotation through 120 can be repeated. Consequently, the sanding sheet 8 which is arranged on the first sanding region 1 can be used about three times as long as a conventional sanding sheet on a hand-held sanding tool according to the prior art.

The service life of the two sanding sheets 8 on the two sanding regions 1, 2 is, however, increased even further compared with the prior art, since, when all three corners 84, 85, 86 of the sanding sheet 8 on the first sanding region 1 are worn, the two sanding sheets 8 are simply exchanged for one another. Thereafter, the sanding sheet 8 which was previously arranged on the second sanding region 2 can in turn be used three times as long - by rotation through 120 in each case - as is possible by

the prior art.

A sanding plate 4 according to the invention thus makes it possible to extend the service life of the sanding sheet 8 considerably - by almost a factor of 6 - compared with the known hand-held sanding tools. Moreover, it is also possible, besides the excellent corner and edge sanding, to produce very good surface sanding.

In the case illustrated, the two sanding areas], 2 together are about 105 cm2 in size.

This corresponds roughly to the size of the rectangular area of the sanding plate base area of a hand-held sanding tool with edge lengths of 80 x 133 mm. In summary, therefore, it can be said that both ecologically and economically, the above-described invention achieves a considerable advance compared with the prior art.

Claims (8)

1. CLAIMS: 1. Sanding plate for a motor-driven hand-held sanding tool, having

   a first sanding region, having a second sanding region and having a connecting region between the first sanding region and the second sanding region, characterised in that the first sanding region and the second sanding region are identically configured and are arranged symmetrically to one another with respect to an axis of symmetry running through the connecting region.
2. 2. Sanding plate according to Claim 1, characterised in that both the first sanding region and the second sanding region each has an equilateral, triangular base area with arcuately outwardly curved edges.
3. 3. Sanding plate according to one of the preceding claims, characterised in that the third edge of the first sanding region lies opposite the third edge of the second sanding region.
4. 4. Sanding plate according to one of the preceding claims, characterised in that it is designed symmetrically with respect to its longitudinal axis.
5. 5. Sanding plate according to one of the preceding claims, characterised in that both the first sanding region and the second sanding region each have a plurality of extraction openings, which are in each case arranged in particular on a circle.
6. 6. Sanding plate according to one of the preceding claims, characterised in that a plurality of extraction ducts are formed in the connecting region.
7. 7. Sanding plate according to Claim 6, characterised in that the extraction ducts are arranged in the border region of the sanding plate.
8. 8. Sanding plate for a motor-driven hand-held sanding tool substantially as herein described with reference to the accompanying drawings.