WO2007110075A1

WO2007110075A1 - Sanding plate part with hard metal grains for replaceable mounting on sanding tools

Info

Publication number: WO2007110075A1
Application number: PCT/DK2007/000141
Authority: WO
Inventors: Svend Jonny Nielsen
Original assignee: Svend Jonny Nielsen
Priority date: 2006-03-24
Filing date: 2007-03-21
Publication date: 2007-10-04
Also published as: DK200600422A

Abstract

There is disclosed a sanding-plate part (4) for mounting on a tool with a number of suction openings (2), typically at least six, for removal of sanding dust, where a metal plate (5) is coated on its front side (3) with a sanding material in the form of grains of hard metal, and on the rear side there is secured a light support plate (6), e.g. of aluminium or fibre-reinforced plastic. On the support plate (6) there are mounted at least two securing elements (7) which extend into the suction openings (2) in the tool, where these openings (2) are substantially cylindrical holes, and the securing elements (7) enter into engagement with the inner walls of the holes (2), so that at least some of the transverse forces from the sanding surface (3) and the reciprocating movement of the sanding-plate part (4) are transferred to the tool's sanding-plate support part (1) in which the suction openings (2) are provided.

Description

SANDING PLATE PART WITH HARD METAL GRAINS FOR REPLACEABLE

MOUNTING ON SANDING TOOLS

The present invention relates to a sanding plate part with a sanding surface to which a sanding coating in the form of grains of hard metal is applied, for replaceable mounting on a tool for the sanding of surfaces, mainly a hand tool, said tool having a sanding-plate support part with a number of suction holes for removal of sanding dust.

BACKGROUND OF THE INVENTION

Sanding-plate parts for replaceable mounting on sanding tools, especially electrical hand tools such as delta-sanders/triangular sanders, orbital Sanders, random orbit sanders, etc., are well-known, where the sanding-plate parts have a rear side of Velcro which cooperates with a corresponding Velcro coating on the tool's sanding- plate support part for fastening the sanding-plate parts and the transfer of forces between the sanding-plate part and the sanding-plate support part in the plane of the sanding surface, i.e. transverse forces which arise when the sanding surface grains are in sanding engagement with a surface.

A second type of coupling between the sanding-plate part and the tool's sanding- plate support part is described in European patent application no. EP 1 607 181, where the sanding-plate part is provided with a number of tongue-shaped fixing elements which are led around the edge of the sanding-pale support part and are secured on the rear of said support part. Such a coupling requires that at least a part of the sanding-plate part is configured in an elastic material.

A sanding coating of hard metal grains soldered on a steel plate is very durable, i.e. it has a very much longer lifetime that a corresponding coating of other sanding grains, but precisely for the reason that the coating is durable and maintains a good sanding ability and that the steel plate is heavy, the transverse forces which shall be transferred between the sanding-plate part and the sanding-plate support part are great, and in practice it has shown that a velcro connection between the two is not sufficiently strong and is worn to pieces.

Alternative sanding-plate parts with hard metal grains are known where the sanding- plate part comprises a coupling to the tool, and the normal sanding-plate support part is dismounted. Different configurations of such sanding-plate parts are described in European patent application no. EP 0 280 786.

With the present invention, the object is to provide an alternative to the necessity of having to replace the normal sanding-plate support part.

BRIEF DESCRIPTION OF THE INVENTION

The present invention solves the above-mentioned problem by providing a sanding- plate part for mounting on a tool with a number of suction openings, typically at least six, for the removal of sanding dust, where a metal plate provided with a sanding coating in the form of hard metal grains on the front and the rear is secured to a light support plate, e.g. of aluminium or fibre reinforced plastic. On the support plate there is mounted at least two securing elements which extend into the suction openings in the tool, these openings being substantially cylindrical holes, and the elements enter into engagement with the inner walls of the holes, so that at least some of the transverse forces from the sanding surface and the reciprocating movement of the sanding-plate part are transferred to the tool's sanding-plate support part in which the suction holes are provided.

It is hereby achieved to provide a replaceable sanding-plate part which can be mounted on the tool's normal sanding-plate support part with suction openings, and which in practice can be used without a Velcro connection getting worm to pieces. Moreover, the metal plate on which the hard metal grains are secured can be a very thin and herewith light plate, where the support plate maintains the plane form of the sanding surface.

The present invention herewith relates to a sanding-plate part for replaceable mounting on a tool for the sanding of surfaces, said tool having a sanding-plate support part with a support surface in which three or more suction holes are provided for the removal of sanding dust, said sanding-plate part comprising a metal plate, preferably of steel, with a sanding surface on which there is applied a sanding coating in the form of grains of hard metal, a support plate with substantially the same extent as the metal plate, where the metal plate is secured to the front of the support plate, and at least two securing elements which are mounted on the support plate and extend away from the rear of said support plate, in that when the sanding-plate part is mounted on the tool, the securing elements extend into corresponding suction openings, and by engagement with the side walls of these openings enable a transfer offerees in the plane of the metal plate between the support plate and the tool's sanding-plate support part.

It is preferred that a plurality of through-going openings are provided in both the metal plate and the support plate, such as at least three or four, and which substantially coincide with the suction openings in the tool's support surface, so that during the use of the tool with the sanding-plate part mounted the sanding dust can be sucked out through the openings in the metal plate.

In a special embodiment, at least one of the securing elements comprises engagement means which can be activated when the securing elements are introduced into the suction openings for achieving engagement between the relevant at least one securing element and the side wall of the corresponding suction opening. This activation can, for example, be that the securing element is moved away from or closer to a second securing element for clamping together around the sanding-plate support part, or the securing element can comprise a flexible bush which by activation is clamped together in the longitudinal direction of the suction opening and which hereby becomes thicker and engages with the side wall of the opening.

In a further embodiment, at least one of the securing means consists of a screw which can possibly be moulded in aluminium, and which has a very large and strong thread with which it can be fastened by engagement in the side wall in the opening in the tool's support plate part, which is made from a flexible material.

In all embodiments in which a screw forms part, the side of the screw head can be provided with narrow ribs which correspond to a series of grooves in a countersinking in the support plate, so that a click effect is achieved when the screw is fastened and it will not be shaken loose during use.

In the following, some examples of different embodiments of the securing elements are described with reference to the accompanying drawings.

At least one of the securing elements can be mounted on the support plate in such a manner that it is displaceable in the plane of the support plate, i.e. in the contact plane between the support plate and the tool's sanding-plate support part, and thus so that it can be adjusted to different distances between the suction openings, in that the positioning and diameters of the openings will typically vary between tools of different manufacturers, and sometimes also between the individual manufacturers' models.

The sanding coating comprises grains of hard metal which are fastened on the metal plate. The fastening is carried out mainly by soldering of the grains to the metal plate, but also brazing, welding and gluing are among the known methods which can be used for fastening the grains on the metal plate. The metal plate is preferably secured to the support plate by adhesion, but the support plate can instead e.g. be moulded directly on the metal plate, or the two plates can be joined together in other ways.

In a preferred embodiment, the thickness of the metal plate is between 0.1 mm and 1 mm, preferably between 0.3 and 0.7 mm.

In preferred embodiments, the area of the sanding surface is between 30 cm² and 500 cm², preferably between 40 cm² and 300 cm².

The outer edge of the metal plate can be bent over away from its sanding surface so that a sharp cutting edge of the metal plate is avoided, the reason being that such an edge can cause damage when sanding close to inside corners etc.

Moreover, it is preferred that between the metal plate and the support plate there is arranged a layer of a flexible material, whereby a certain flexibility of the sanding surface is achieved, especially when the metal plate is thin, i.e. between 0.3 mm and 0.7 mm. The flexible material can be a natural or artificial rubber, and the so-called foam rubber is particularly suitable. The preferred thickness of the layer of flexible material is from 1 mm to 6 mm, preferably from 2 mm to 4 mm.

The support plate can be moulded in a plastic material, preferably with added fibres for reinforcement of the material, preferably in a weight ratio of 10-40% of the total weight of the plastic material. The fibres can be glass fibres or natural fibres such as sisal, hemp, coconut or cellulose fibres, but carbon fibres can also be used.

As a second alternative embodiment, the support plate can be made of aluminium or a metal alloy with a major content of aluminium. The thickness of the support plate is preferred to be between 1 mm and 8 mm, preferably between 2 mm and 5 mm.

The sanding-plate part according to the present invention can be used for sanding surfaces with large grains, i.e. a low grade or grit, in that high transverse forces can be transferred. The grade of the sanding surface is preferably greater than 120, and it is preferred that it is between 80 and 14, the grade being a standardised measure for the number of grains per square inch.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are shown in the accompanying drawing, where

Figs. 1-5 show sanding-plate support parts for different tools,

Figs. 6 and 6a show a first embodiment for the invention seen respectively from below and in an exploded view seen from the side,

Figs 7, 7a and 7b show a second embodiment for the invention seen respectively from below and in an exploded view seen from the side,

Figs 8 and 8a show a third embodiment for the invention seen respectively from below and in an exploded view seen from the side,

Figs 9 and 9a show a fourth embodiment for the invention seen respectively from below and in an exploded view seen from the side, and

Figs. 10, 10a and 10b show a fifth embodiment for the invention seen respectively from below and in an exploded view seen from the side. Fig. 11 shows sixth embodiment for the invention seen in an exploded view from the side.

Figs 12 and 12a show a seventh embodiment for the invention seen respectively from the side and from above.

The shown embodiments are used as illustrations of the invention and shall not be considered to limit the protective extent as disclosed by the accompanying claims.

DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION

Figs. 1-5 show sanding-plate support parts 1 for different tools, where suction openings 2 are provided in the sanding-plate support parts 1 so that sanding dust can be sucked from the sanding surface 3 of the sanding-plate part 4 through corresponding holes in said sanding plate part. The tools are chiefly hand tools and they are preferably electrically driven, but the present invention can also be used with manually-driven tools such as a rasp with suction openings.

Figs. 6 and 6a show a first embodiment for a sanding-plate part 4. The sanding-plate part 4 consists of a 0.5 mm thick steel plate 5 with grains of hard metal soldered on the sanding surface 3. The rear of the steel plate is fastened to a stiff, fibre-reinforced plastic support plate 6 on which there are mounted two spigots 7 which constitute the securing elements 7, and which shall enter into engagement with suction openings 2 in the sanding-plate support part 1. Between the steel plate 3 and the support plate 6 there is placed a flexible intermediate layer 8 of foam rubber, and the three parts 3, 6, 8 are fastened to one another by gluing, so that they form a single unit.

In this embodiment, the spigots 7 consist of two tubes which pass down in corresponding suction openings 2, and the suction from the sanding surface 3 can take place through these tubes 7 via corresponding openings in the steel plate 3 and the flexible intermediate layer 8. In order to secure the sanding-plate part, there can also be provided a Velcro surface on that side of the support plate 6 which faces towards the sanding-plate support part 1, which is provided with a corresponding Velcro surface.

Figs. 7, 7a and 7b show a second embodiment for the invention, where the securing elements 7 comprise a screw 9, an elastic ring of rubber 10 and an end plate 11. Alternatively, the elastic ring 10 can be replaced by an elastic cone 12 as shown in fig. 7b. By tightening the screw 9 via corresponding openings in the steel plate 3 and the flexible intermediate layer 8, the end plate 11 is drawn up against the support plate 6 and the elastic ring 10 or cone 12 expands and clamps against the sides of the suction holes 2, whereby the sanding-plate part 4 is held in place during use.

Figs. 8 and 8a show a third embodiment for the invention, where the securing elements 7 have an eccentric opening for a screw 9, so that the elements 7 can be displaced for adjustment of their distance to the actual distance between the suction openings 2 in the sanding-plate support part 1 on which the sanding-plate part 4 shall be placed, and when the securing elements 7 are placed in the openings 2 they can be displaced so that they clamp firmly against the side walls of the openings 2 for the securing of the sanding-plate part 4.

Figs. 9 and 9a show a fourth embodiment for the invention, where the securing elements 7 can be displaced in slots 13 in the support plate 6, and thereafter fastened by tightening the screws 9, whereby both an adjustment and a clamping-fast can take place.

Figs 10, 10a and 10b show a fifth embodiment for the invention, where the securing elements 7 comprise pins 14 with a head 15 (fig. 10a) or pins 14 with threads 16, transverse slots or the like, where the pins 14 can be mounted with flexible bushes 17 e.g. of rubber. The sanding-plate 4 can form part of a set with several bushes 17 of several different outer diameters, so that the securing elements 7 can be adjusted for suction openings 2 of different inside diameters.

Fig. 11 shows a sixth embodiment for the invention, where a securing element 7 consists of a screw 18 which is preferably moulded in aluminium, and which has a very large and strong thread 19 with which it can be secured by engagement with the side wall in the opening 2 in the tool's support plate part 1, which consists of a flexible material. In the embodiment shown, the screw is placed in a countersinking 20 in the support plate 6.

Fig. 12 shows a seventh embodiment for the invention, where the securing element 7 consists of a screw 18 as shown in Fig.l 1. In the embodiment shown, the head of the screw 18 is provided with a series of ribs 21 which correspond to a series of grooves 22 in the countersinking 20 in the support plate 6, so that a click effect is achieved when the screw is tightened and it is not shaken loose during use of the tool. In Fig. 12a the countersinking 20 with grooves 22 in the support plate 6 is shown from above. The countersinking 20, ribs 21 and grooves 22 can be used in connection with all embodiments which involve screws in the securing elements 7.

It will be obvious to persons skilled in the art that the different embodiments shown have characteristics which can be combined in achieving several embodiments, all of which fall within the scope of the invention.

Moreover, it is general for all embodiments that through-going openings (not shown) are provided in the steel plates 5, the flexible intermediate layer and the support plates 6, where these openings conform with corresponding suction openings 2 in the support plate part 1, so that sanding dust can be sucked away from the sanding surface 3.

Claims

PATENT CLAIMS

1. Sanding-plate part (4) for replaceable mounting on a tool for the sanding of surfaces, said tool having a sanding-plate support part (1) with a support surface in which three or more suction openings (2) are provided for the removal of sanding dust, said sanding-plate (4) comprising a metal plate (5), preferably a steel plate (5), with a sanding surface (3) on which there is applied a sanding coating in the form of grains of hard metal and a support plate (6) with substantially the same extent as the metal plate (5), the metal plate (5) being secured to the front of the support plate (6),

c h a r a c t e r i s e d in that

the sanding-plate part (4) further comprises at least two securing elements (7) which are mounted on the support plate (6) and extend away from its rear side, and in that the securing elements (7), when the sanding-plate part (4) is mounted on the tool, extend into corresponding suction openings (2), and by engagement with the side walls of these openings enable forces in the plane of the metal plate (5) to be transferred between the support plate (6) and the tool's sanding-plate part (1).

2. Sanding-plate part (4) according to claim 1, where at least one of the securing elements (7) comprises engagement means (9-22) which can be activated when the securing elements (7) are introduced into the suction openings (2) for achieving engagement between the relevant at least one securing element (7) and the side wall of the corresponding suction opening (2).

3. Sanding-plate part (4) according to claim 1 or 2, where at least one of the securing elements (7) is mounted on the support plate (6) in a manner in which it is displaceable in the plane of the support plate (6), thus enabling it to be adjusted for different distances between the suction openings (2).

4. Sanding-plate part (4) according to any of the preceding claims, where the grains of hard metal are fastened to the metal plate (5) by soldering.

5. Sanding-plate part (4) according to any of the preceding claims, where the metal plate (5) is fastened to the support plate (6) by gluing.

6. Sanding-plate part (4) according to any of the preceding claims, where the thickness of the metal plate (5) is between 0.1 mm and 1 mm, preferably between 0.3 mm and 0.7 mm.

7. Sanding-plate part (4) according to any of the preceding claims, where the area of the sanding surface (3) is between 30 cm² and 500 cm², preferably between 40 cm² and 300 cm².

8. Sanding-plate part (4) according to any of the preceding claims, where the outer edge of the metal plate (5) is bent over away from its sanding surface.

9. Sanding-plate part (4) according to any of the preceding claims, where between the metal plate (5) and the support plate (6) a layer (8) of a flexible material is arranged.

10. Sanding-plate part (4) according to claim 9, where the thickness of said layer (8) is from 1 mm to 6 mm, preferably from 2 mm to 4 mm.

11. Sanding-plate part (4) according to any of the preceding claims, where the support plate (6) is moulded in plastic material.

12. Sanding-plate part (4) according to claim 11, where fibres are added to the plastic material for reinforcement of the material, preferably in the weight ratio of 10-40% of the total weight of the plastic material .

13. Sanding-plate part (4) according to any of the claims 1-10, where the support plate (6) is made from aluminium or a metal alloy with a major content of aluminium.

14. Sanding-plate part (4) according to any of the preceding claims, where the thickness of the support plate (6) is between 1 mm and 8 mm, preferably between 2 mm and 5 mm.

15. Sanding-plate part (4) according to any of the preceding claims, where the grade of the sanding surface (3) is greater than 120, preferably between 80 and 14.

16. Sanding-plate part (4) according to any of the preceding claims, where in both the metal plate (5) and the support plate (6) there is provided a plurality of through- going openings which correspond substantially to the suction openings (2) in the tool's support surface, so that during use of the tool with the sanding-plate part (4) mounted the sanding dust can be sucked out through the openings in the metal plate (5).