TOOL HAVING A ROTATING PROCESSING UNIT

Abstract

A tool with a rotating processing unit with tool elements, preferably an abrading or polishing tool, and with a motor including a drive shaft for driving the processing unit is provided. The drive shaft is drivingly connected with a drive plate disposed at right angles to the drive shaft and provided with first connecting device releasably interacting with corresponding second connecting device which are connected with a base plate for the processing unit. The processing unit will thus be driven by the engagement of the first and second connecting device. The tool elements are fixed in the base plate. By this design it is possible for a user to replace the processing unit rapidly and in a simple way without needing to replace the individual tool elements.

Description

FIELD OF THE INVENTION

The present invention concerns a tool with rotating processing unit with tool elements, preferably an abrading or polishing tool, and with a motor including a drive shaft for driving the processing unit, wherein the drive shaft is drivingly connected with a drive plate disposed at right angles to the drive shaft. The tool is preferably a handheld tool. However, the invention may as well be applied to a stationary tool.

BACKGROUND OF THE INVENTION

The area of the invention is within tools for abrading and polishing and therefore provided with tool elements in the form of abrasive elements. However, the invention may also be used with other processing units, such as e.g. buff wheels.

Rotating abrasive or polishing tools provided with abrasive elements are known. Such tools are used extensively in the woodworking industry and within the metalworking industry. Similarly, the tools can be used within industries for working other materials, as e.g. glass fibre constructions.

By surface treatment, as e.g. sanding or polishing, of various items, it is known to use abrading and polishing members which are mounted on a processing unit in the form of an abrading/grinding head. Such an abrading head can be disc-shaped wherein the abrasive elements are mounted on a side face of the disc or built up as combination of disc-shaped and cylindrical parts. However, it is typical of these abrading heads that they are provided with a kind of dovetail grooves in which a number of abrasive and/or brush members are mounted. These members may include abrasive elements in the form of abrasive paper, brushes of fibre, hair, steel or other metals and combinations of these, e.g. in the form of retainer brushes supporting the abrasive paper during use. The abrasive paper can e.g. be sandpaper for buffing wood, metal and the like, cloth and/or fabric for polishing, or leather. Brushes, support brushes and/or retainer brushes may e.g. be steel brushes, plastic brushes or other types of brushes.

In the following, these members are designated by a common term as tool elements.

Such tool elements can be made of a plastic material in which abrasive paper and brushes are embedded by moulding a plastic member around abrasive paper and brush. Alternatively, brushes and/or abrasive paper can be fixed in a metal rail by squeezing the latter around the brushes and/or the abrasive paper of which the tool member in question is to be made, or in other suitable ways.

On a typical abrading head are arranged as an average between 8 and 50 tool elements which are to be replaced regularly by industrial use. Such a replacement typically occurs by pulling them out of the dovetail grooves in which they are seated and replacing them with new tool elements.

The drawback of the different types of abrading heads, and for that matter also of the different types of tool elements for use in these abrading heads, is that the different tool elements do not fit all types of abrading heads.

Therefore, it is often necessary to acquire many different types of abrading heads and/or tool elements in order to perform different tasks, obviously entailing increased use of time for changing a tool or a machine on which the abrading head is applied, as well as a greater investment in abrading heads.

In particular when grinding profiled work pieces in the wood industry, it is important to have a rotating processing head with variable speed which can be used in connection with various forms of processing heads for abrading, trimming and polishing.

From industrial works, preferably in the wood industry, abrading tools are known having variable speed and in the form of pneumatic tools with abrading heads mounted thereon. It is also known with hand tools with abrading heads driven by an electric motor with variable speed.

In spite of a long-standing need for hand tool which can also be used by do-it-yourself users who need rapid and simple replacement of the processing unit in order to have various tool elements available for different processing operation, such a hand tool with a processing unit which is easy to replace and which is intended for abrading, trimming and polishing has not previously existed.

An apparatus of the type mentioned in the introduction is known from US 2008171495. This tool comprises a drive plate where tool elements are mounted in a replaceable way. However, this does not solve the problem of easy replacement and change between different types of tool elements by replacing the entire processing unit.

Thus there is an unsatisfied demand for a hand tool which can be used by the professional user as well as the do-it-yourself user, and where instead of replacing the abrading tool the entire processing unit is replaced.

By making the processing tool as a disposable unit which is replaced when worn, there is a need for a construction which is more reasonably priced than the hitherto known, wherein the holder for abrading tools of the processing unit is made by milling grooves in the holder, which e.g. can be a cup head or a drum. This is particularly significant to hand tools for the do-it-yourself user.

OBJECT OF THE INVENTION

It is the object of the present invention to indicate a tool in which different types of tool elements are mounted on different processing units, and where the processing units are easy to replace in order to change between different processing units and in order to replace the unit by wear. Furthermore, it is an object to indicate a processing unit which is suited for disposable use by being a cheap design.

DESCRIPTION OF THE INVENTION

According to the present invention, this object is achieved by a tool of the kind mentioned in the introduction which is peculiar in that the drive plate is provided with first connecting means releasably interacting with corresponding second connecting means which are connected with a base plate for the processing unit such that the processing unit is driven by engagement of the first and second means, and that the tool elements are fixedly mounted in the base plate.

By establishing the interacting connection means on the base plate of the processing unit and the drive plate of the drive shaft, a suitable choice of connecting means can be performed so that they can be released quickly. Suitable choices will typically be Velcro connections and bayonet connections which can readily be engaged or disengaged. The user can hereby readily replace the processing unit.

The processing unit can be replaced by a corresponding processing unit in case of wear or by another type of processing unit when different tasks are to be performed in continuation of each other. The drive shaft is usually a rigid shaft but it is also possible that the drive shaft of the tool is a flexible shaft.

By the tool according to the invention it is thus possible for a user to apply the same motor unit to different processing units which can be replaced without using tools in a simple way. The motor unit can be a pneumatic motor with variable speed or an electric motor. An electric motor can also have variable speed.

The tool elements will be fixedly mounted in the base plate of the processing unit. It is therefore not intended that individual tool elements are to be replaced as is the case with prior art tools. Thus there is no need that a do-it-yourself user has to keep track of the various tool elements for the tool. When the tool elements are worn, the user can simply replace the processing unit. In other words, it can be said that the invention operates with disposable processing units.

By using a tool according to the invention with rapid mounting and dismounting of the processing unit, it is possible in a tool to use a plurality of processing units which are mutually replaced, depending on the processes to be performed. The various processing units fit into the tool as modular elements.

According to a further embodiment, the tool according to the present invention is peculiar in that the base plate of the processing units in the form of top plate, bottom plate and spacer housing are made by casting. As opposed to the machined parts of prior art processing units, this will enable a cheap construction. The production costs can hereby be reduced to a level that makes the processing units suited for disposable use.

According to a further embodiment, the tool according to the invention is peculiar in that first and second connecting means are selected among Velcro connections and bayonet connections.

The applied first and second connecting means are to have a design such that they can transmit the torque required for using the tool. If a bayonet socket is used, the engagement of the bayonet will be adapted such that by rotation in the peripheral direction of the tool there is established a locking engagement in the bayonet socket.

If using Velcro connections, by the present-day Velcro connections it will be possible to transmit torques with a magnitude as applied by rotary hand tools.

In that connection it is remarked that the tools can typically be expected to be hand tools with a motor capacity in the magnitude up to about 3500 W.

As mentioned above, Velcro connections and bayonet connections will be very simple as tools are not required when mounting and dismounting a processing unit from the drive plate of the tool.

According to a further embodiment, the tool according to the invention is peculiar in that the drive plate and the processing unit are enclosed by a housing which is fixed in relation to the motor and which is provided with a connection for exhausting material removed by the use of the tool elements of the processing unit, as the drive plate and the processing unit are provided with openings for passage of the material.

As the tools are typically used for abrading or trimming tasks, it is essential that the dust formed by abrasion/trimming can be removed in a safe way. Therefore it is preferred that the processing unit is enclosed by a housing such that only the tool elements are exposed. In the base plate of the processing unit, openings are provided between the tool elements. These openings communicate with corresponding openings in the drive plate. Dust can hereby be sucked into the housing through these openings and be remove via the exhaust connection.

Moreover, the surrounding housing will constitute a safeguard as the rotating periphery of the processing unit is not exposed. The risk of injury is reduced thereby.

According to a further embodiment, the tool according to the present invention is peculiar in that that the tool elements of the processing unit includes means for abrading, trimming, polishing, or similar tasks.

As mentioned above, a tool according to the present invention will primarily find application for abrading and polishing tasks. The tool elements will therefore be means for abrading, trimming, polishing, or similar tasks. Such tool elements can be chosen with a design which is known per se from the previously mentioned industrial machines with replaceable tool elements.

According to a further embodiment, the tool according to the present invention is peculiar in that the base plate of the processing unit is a circular disc rotating about a central axis and having a surface to which edge parts of a number of pieces of abrasive paper, which are slit inwardly against the surface, are fitted orientated largely perpendicularly out from the surface. The pieces of abrasive paper are preferably disposed radially.

As an alternative to an orientation largely at right angles to the surface, the tool elements can be disposed at an angle which deviate from right angles relative to the surface. Also, it will be possible to dispose the tool elements with an orientation which is not completely radial but at an angle to a radial orientation.

By an inclining mounting of the tool elements it is possible to change the processing properties of the tool.

By such a construction there is established an abrasive member where the use of slit abrasive paper pieces is particularly suited for abrading profiled surfaces. The slit abrasive paper pieces on the face of a circular disc are known per se from previous apparatuses where replaceable tool elements are used.

According to a further embodiment, the tool according to the present invention is peculiar by also including support brushes supporting the pieces of abrasive paper as the pieces of abrasive paper and the support brushes are secured in a common foot piece which is mounted in the base plate of the processing unit.

The application of support brushes provides a particularly efficient abrading action.

According to a further embodiment, the tool according to the present invention is peculiar in that the pieces of abrasive paper and the support brushes are mounted in foot pieces, that the base plate includes a bottom plate and a top plate provided with mounting apertures for the foot pieces, that the foot pieces ore oversized at their bottoms compared with the mounting apertures such that the foot pieces are secured in the mounting apertures when joining the bottom plate and the top plate. The mounting apertures are formed as openings that surround the foot pieces.

By using foot pieces which at their bottom are oversized in relation to mounting apertures in the top plate it is possible to insert the individual tool elements from the back side of the top plate. After insertion of the tool elements in the apertures, the bottom plate and the top plate are joined with the bottom of the foot pieces located between the top plate and the bottom plate. The bottom plate will hereby press the foot pieces into secure engagement in the mounting apertures. Bottom plate and top plate can be interconnected in various known ways, e.g. by gluing, welding or by mechanical clamping.

The tool elements will then project from the top side of the top plate of the base plate. The connecting means are disposed at the side of the bottom plate of the base plate facing the drive plate of the drive shaft.

According to a further embodiment, the tool according to the present invention is peculiar in that the processing unit includes a circular disc or wheel rotating about a central axis and having a surface upon which is mounted a disc-shaped piece of abrasive paper.

The processing unit will preferably include a circular disc. Alternatively, discs with an edged or other shape can be used. The applied disc will rotate about a central axis. A rotationally symmetric tool is hereby achieved. On the circular disc there is a plane surface upon which there can be fitted a disc-shaped abrasive paper piece, alternatively a polishing means.

By using the tool there will thus be abrading with a plane tool unit. The tool element can be mounted on a soft and yielding base for adapting to various surface contours when abrading.

According to a further embodiment, the tool according to the invention is peculiar in that the processing unit and the drive plate are aligned for rotation about a common central axis.

By a common central axis for processing unit and drive plate there is achieved a simple design of the abrading tool, and there is no risk of adverse effects occurring by shaking and vibrations, as known e.g. from eccentric grinders.

According to a further embodiment, the tool according to the invention is peculiar by including several processing units adapted for mutual substitution for application to different processing operations. Each processing unit has second connecting means that interact releasably with the first connecting means.

Now is given an explanation in detail of special tool elements in the form of slit abrasive paper for use in the tool.

The lamellae of the abrasive element are formed by cutting an abrasive paper transversely of its longitudinal direction so that strips or lamellae appear which at one end are interconnected by means of an unbroken strip of abrasive paper secured to the U-shaped profile. The free end thus consists of a number of parallel lamellae of abrasive paper extending largely at right angles to the longitudinal direction of the profile. In a plane parallel with the abrasive lamellae, support brushes will be disposed in immediate vicinity of the lamellae such that they support the lamellae by grinding.

The abrasive or polishing effect is obtained as a result of the action of the lamellae as they sweep a work piece during rotation of the tool. The support brushes, as indicated by the word, have a function of supporting the abrasive lamellae. However, the support brushes can also be produced from a material such that they contribute to the abrasive or polishing effect. The support brushes are placed right behind the abrasive paper pieces so that they support the abrasive paper pieces and thereby hold the abrasive part of the abrasive paper pieces against the surface to be abraded.

Furthermore, the support brushes provide that the abrasive paper items will never bend around the foot and lie back across the surface of the abrading wheel. It is an advantage that there is a certain distance from the surface of the abrading wheel and down to the surface to be abraded such that abraded material can be conveyed away and for reducing the risk of the surface of the abrading wheel coming into contact with the abraded surface.

The number of rows of support brushes may be different, depending on how much support the abrasive paper pieces are to have. This entails that e.g. there may be three rows of support brushes behind each individual abrasive paper piece.

By the abrasive paper pieces being mounted mainly perpendicularly on the surface of the wheel, it is possible to utilise the abrasive part of the abrasive paper pieces better than in the case with abrasive paper pieces that are placed intentionally with large overlaps. An abrading wheel according to the present invention has thus a longer service life than the commonly known flat or annular grinding wheels.

With an interspace between the abrasive paper pieces is furthermore achieved a better grinding effect as the interspaces contribute to transport abraded material away from the abrasive paper pieces, whereby the abrasive parts of the abrasive paper pieces are provided a better abrasive effect because they are not filled up with abraded material. Also, exhaust of abraded material from the interspaces can easily be effected.

Instead of mounting the abrasive paper pieces so that they have a radial extension over the greater part of the radius of the surface, the abrasive paper pieces can be mounted in relation to the direction of rotation in a rearwards curved arrangement.

As it appears from the above explanation, a tool according to the invention can be regarded as a modular tool where individual modules used in the processing units can be reused with various tool elements. This makes the tool suited for do-it-yourself users who only need a motor unit in order to have a number of different processing units available.

Change between individual processing units is easily performed due to the releasable connecting means. For example, a user who is about to trim a surface with a processing unit with abrasive lamellae will encounter an area with large irregularities or burrs that are difficult to remove with a trimming unit. The user can then readily change the trimming unit with a plane grinding unit and remove the irregularities, and then mount the trimming unit in the tool again. This reduces the need for the number of tools which are to be available for the user.

DESCRIPTION OF THE DRAWING

In the following, the invention will be explained in more detail with reference to the enclosed drawing wherein:

FIG. 1 shows an exploded view of a tool according to the invention, illustrated with three interchangeable processing units;

FIG. 2 shows different views of a first of the processing units in FIG. 1 in the form of an abrading head with abrasive strips mounted at right angles to the base plate of the processing unit and with radial orientation;

FIG. 3 shows different views of a top plate for the base plate shown in FIG. 2;

FIG. 4 shows different views of a bottom plate for the base plate shown in FIG. 2;

FIG. 5 shows different views of a second of the processing units shown in FIG. 1 in the form of an abrading head with abrasive strips mounted obliquely to the base plate of the processing unit and with a non-radial orientation;

FIG. 6 shows different views of a top plate for the base plate shown in FIG. 5;

FIG. 7 shows different views of a bottom plate for the base plate shown in FIG. 5;

FIG. 8 shows different views of a third of the processing units in FIG. 1 in the form of a grinding wheel with a face at which a disc-shaped abrasive paper is mounted;

FIG. 9 shows a various views of a housing for the tool shown in FIG. 1;

FIG. 10 shows a various views of a drive plate for the tool shown in FIG. 1;

FIG. 11 shows connecting means in the form of a Velcro male part for the tool shown in FIG. 1;

FIG. 12 shows connecting means in the form of a Velcro female part for the tool shown in FIG. 1; and

FIG. 13 shows different views of connecting means in the form of a bayonet connection shown together with a processing unit corresponding to the one shown in FIG. 5.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the different figures on the drawings identical or corresponding elements will be indicated with the same reference number and a specific explanation to each single figure will therefore not be given.

In FIG. 1 is shown a tool 1, including a motor 2 with a drive shaft 3, a housing 4, a drive plate 5 and three different processing units 6, 7 and 8. The motor 2 is a pneumatic motor with three handles 9 and a connection 9′ for connecting air in one of the handles.

FIG. 2 shows details of the first processing unit 6. It includes a base plate 10 formed by a top plate 11 and an interacting bottom plate 12. There are eight radially oriented mounting apertures 13 for receiving eight tool elements in the form of abrasive elements 14, and eight exhaust openings 15 provided there between. Each abrasive element 14 includes a foot piece 16 in the form of a plastic strip in which is embedded slit abrasive paper pieces 17 as well as support brushes 18. Exhaust openings 24 aligned with the exhaust openings 15 are formed in the bottom plate 12.

The foot pieces 16 are designed with increased thickness such that they have a bottom 19 which is wider than their top 20. Hereby, they can be mounted in the mounting openings 13 from a back side 21 of the top plate 11 such that the abrasive paper pieces 17 project from the front side 22 of the top plate 11, disposed largely at right angles to the front side 22 as the foot pieces 16 are welded to perpendicularly collared edge parts 23 on the mounting apertures 13. The bottom plate 12 is glued on the top plate 11 such that there is formed a jointed base plate 10 with fixed abrasive elements 14.

The top plate 11 is shown in several views in FIG. 3, and the bottom plate 12 is shown in several views in FIG. 4.

The processing unit 6 is provided with a glued Velcro female part 25 which at its peripheral edge 26 has finger-like cutouts 27 that facilitate separation from a corresponding Velcro male part 28 (see FIG. 11) which is glued on the drive plate 5. The Velcro female part 25 and the Velcro male part 28 have aligned exhaust openings 29 and 30, respectively.

FIG. 5 shows a second processing unit 7 differing from the one shown in FIG. 2 in that the abrasive elements 14 are mounted in the top plate 11′ in mounting openings 13′ which are non-radially oriented and have obliquely collared edge parts 23′ for receiving the abrasive elements 14 at an angle of 60° relative to the front side 22. In the bottom plate 12′, opposite each abrasive element 14, there are a series of outwardly bent extensions 31 supporting the bottom 20 of the foot piece 16 in order to ensure the oblique orientation.

The top plate 11′ is shown in several views in FIG. 6, and the bottom plate 12′ is shown in several views in FIG. 7.

FIG. 8 shows a second processing unit 8. This processing unit is a surface grinder and includes a cylindrical spacer housing 32 on which is glued a Velcro female part (not shown in FIG. 8) intended for interaction with a Velcro male part 28 which is glued to the drive plate (not shown in FIG. 8). Exhaust openings 36 are formed in the spacer housing 32. On the spacer housing 32 is mounted an elastic intermediate piece 33 with finger-like cutouts 34 and exhaust openings 35. On the intermediate piece 33 is glued a Velcro female part 25 which interacts with a Velcro male part (not shown in FIG. 8) glued to a round, disc-shaped abrasive paper piece 46 provided with exhaust openings 35. All exhaust openings are aligned.

FIG. 9 shows the housing 4 for surrounding the drive plate 5 and a processing unit 6, 7 or 8. The housing includes a bottom 37 with an exhaust connection 38 intended for connecting with an exhaust system (not shown). The housing 4 furthermore includes a mounting ring 39 for use when fastening the housing on the motor 2. The housing includes a cylindrical ring 40 constituting a cylindrical jacket on the housing. A brush ring 41 is fitted on the cylindrical ring. The brush ring 41 can be made with different heights, e.g. 5 mm, 10 mm and 15 mm, such that it will contribute to defining the pressure which will be exerted by abrasive elements in the housing 4 on a base.

FIG. 10 shows the drive plate 5. The drive plate 5 is formed by a plate 42 and a Velcro male part 28. These two parts are glued together. By means of lock nut 43, the drive plate 5 is screwed on a hub 44 which is mounted on the drive shaft 3 of the motor. The plate 42 is provided with exhaust openings 45 that are aligned with the exhaust openings 29 on the Velcro male part 28.

FIG. 11 and FIG. 12 show the Velcro male part 28 and the Velcro female part 25, respectively.

FIG. 13 shows the first and second connecting means in the form of a bayonet connection 47, 48 which include collared flanges 47 spaced along the periphery of an annular wall 49 rising at right angles from a disc-shaped plate 50 along the periphery 51 of the latter such that a bowl-shaped drive plate 5′ is formed. The drive plate 5 is provided with exhaust openings 45.

The bayonet connection 47, 48 furthermore includes projecting flanges 48 which are distributed along the peripheral edge 52 of a circular base plate 11″, which between the flanges 48 have notches 53 distributed along the peripheral edge so that the base plate 11″ can be placed within the bowl-shaped drive plate 5′ when the notches 53 are aligned with the collared flanges 47. The base plate 11 can then be rotated such that the projecting flanges 48 are brought to engage under the collared flanges 47.

The bayonet connection is shown on a processing unit corresponding to the one shown in FIG. 5, with mounting apertures 13″ for abrasive elements 14 and with exhaust openings 15. However, corresponding bayonet connections can be provided in connection with the other two types of processing units such that rapid replacement and change between different processing units are possible.

Claims

1. A tool with rotating processing unit with tool elements, preferably an abrading or polishing tool, and with a motor including a drive shaft for driving the processing unit, wherein the drive shaft is drivingly connected with a drive plate disposed at right angles to the drive shaft, wherein the drive plate is provided with first connecting means releasably interacting with corresponding second connecting means which are connected with a base plate for the processing unit such that the processing unit is driven by engagement of the first and second means, and that the tool elements are fixedly mounted in the base plate.

2. The tool according to claim 1, wherein the first and second connecting means are chosen among hook and loop connections and bayonet connections.

3. The tool according to claim 1 wherein the drive plate and the processing unit are enclosed by a housing which is fixed in relation to the motor and which is provided with a connection for exhausting material removed by the use of the tool elements of the processing unit, as the drive plate and the processing unit are provided with openings for passage of the material.

4. The tool according to claim 1, wherein the tool elements of the processing unit include means for abrading, trimming, polishing, or similar tasks.

5. The tool according to claim 1, wherein the base plate of the processing unit is a circular disc rotating about a central axis and having a surface to which edge parts of a number of pieces of abrasive paper, which are slit inwardly against the surface, are fitted orientated largely perpendicularly out from the surface.

6. The tool according to claim 5, wherein support brushes supporting the pieces of abrasive paper as the pieces of abrasive paper and the support brushes are secured in a common foot which is mounted in the base plate of the processing unit.

7. The tool according to claim 5 wherein the pieces of abrasive paper and the support brushes are mounted in foot pieces, that the base plate includes a bottom plate and a top plate provided with mounting apertures for the foot pieces, that the foot pieces are oversized at their bottoms compared with the mounting apertures such that the foot pieces are secured in the mounting apertures when joining the bottom plate and the top plate.

8. The tool according to claim 1, wherein the processing unit includes a circular disc rotating about a central axis and having a surface upon which is mounted a disc-shaped piece of abrasive paper.

9. The tool according claim 1, wherein the processing unit and the drive plate are aligned for rotation about a common central axis.

10. The tool according to claim 1, wherein several processing units are adapted for mutual substitution for application to different processing operations.

11. The tool according to claim 1, wherein the base plate of the processing unit is made by casting.