U.S. patent application number 12/035713 was filed with the patent office on 2008-08-28 for abrasive element.
This patent application is currently assigned to SIA ABRASIVES INDUSTRIES AG. Invention is credited to Patrick Muller.
Application Number | 20080207101 12/035713 |
Document ID | / |
Family ID | 38006616 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080207101 |
Kind Code |
A1 |
Muller; Patrick |
August 28, 2008 |
Abrasive Element
Abstract
An abrasive element has a first surface region which coincides
with an enveloping surface of the element, and a second surface
region which does not. When the element is pressed against a planar
surface, part of the second surface region, which is provided with
abrasive material, comes into contact with the surface. Also
disclosed are a system comprising at least two part-elements which
can be connect to form an abrasive element, and methods for making
and using the abrasive element.
Inventors: |
Muller; Patrick; (Huttwilen,
CH) |
Correspondence
Address: |
SHOEMAKER AND MATTARE, LTD
10 POST OFFICE ROAD - SUITE 110
SILVER SPRING
MD
20910
US
|
Assignee: |
SIA ABRASIVES INDUSTRIES AG
Frauenfeld
CH
|
Family ID: |
38006616 |
Appl. No.: |
12/035713 |
Filed: |
February 22, 2008 |
Current U.S.
Class: |
451/539 ;
451/533; 451/66; 451/84 |
Current CPC
Class: |
B24D 18/0072 20130101;
B24D 5/14 20130101; B24D 13/14 20130101; B24D 5/06 20130101; B24D
7/14 20130101 |
Class at
Publication: |
451/539 ; 451/84;
451/66; 451/533 |
International
Class: |
B24D 11/00 20060101
B24D011/00; B24C 3/20 20060101 B24C003/20; B24B 7/00 20060101
B24B007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 22, 2007 |
EP |
07102865.8 |
Claims
1. Abrasive element with at least a first surface region and at
least a second surface region, wherein at least part of said first
surface region coincides with part of an enveloping surface of said
abrasive element, at least part of said second surface region does
not coincide with said enveloping surface of said abrasive element,
at least part of said abrasive element is elastically compressible
in such a way that, when said abrasive element is pressed against a
substantially planar surface, at least part of said second surface
region can be brought into contact with said surface, and at least
a partial region of said second surface region is provided with an
abrasive material.
2. Abrasive element according to claim 1, wherein said first
surface region is substantially planar or comprises substantially
planar partial surfaces and/or said second surface region extends
substantially parallel to said first surface region.
3. Abrasive element according to claim 1, wherein at least parts of
said first surface region are provided with an abrasive
material.
4. Abrasive element according to claim 3, wherein said abrasive
materials on said first surface region and on said second surface
region are different from one another.
5. Abrasive element according to claim 1, wherein it is formed as a
sponge, pad, sheet or belt.
6. Abrasive element according to claim 1, wherein the element is
formed in a substantially disc-shaped or cylindrical manner, said
first surface region comprising surfaces of elevations which
protrude at the outer circumference and said second surface region
comprising depressions in a radial direction.
7. Abrasive element according to claim 6, wherein at least parts of
said elevations have a lower compressibility than the remaining
part of said abrasive element.
8. Abrasive element according to claim 6, wherein at least one of
said elevations has a beveled and/or rounded portion.
9. Abrasive element according to claim 5, wherein said first
surface region is formed by the surfaces of at least one elevation,
which are arranged on said abrasive element, and said second
surface region is partially formed by a base area on which said at
least one elevation is arranged.
10. Abrasive element according to claim 9, wherein at least parts
of said elevations have a lower compressibility than the remaining
part of said abrasive element.
11. Abrasive element according to claim 5, wherein the element
comprises foam.
12. Abrasive element according to claim 11, wherein the element
comprises foam in parts of said elevations.
13. Abrasive element according to claim 5, wherein the element
comprises at least two part-elements that are connected or can be
connected to one another.
14. Abrasive element according to claim 13, wherein at least part
of the surface of a first part-element forms part of said first
surface region and at least part of the surface of a second
part-element forms part of said second surface region.
15. Abrasive element according to claim 13, wherein at least two of
said part-elements are formed from materials that are different
from one another.
16. System comprising at least two part-elements, at least one of
which comprises a surface which is at least partially provided with
an abrasive material, wherein at least two of said part-elements
can be connected to one another in such a way that an abrasive
element having a form selected from the group consisting of sponge,
pad, sheet, belt, disc and cylinder is obtained, wherein the
abrasive element has at least a first surface region and at least a
second surface region, wherein at least part of said first surface
region coincides with part of an enveloping surface of said
abrasive element, at least part of said second surface region does
not coincide with said enveloping surface of said abrasive element,
at least part of said abrasive element is elastically compressible
in such a way that, when said abrasive element is pressed against a
substantially planar surface, at least part of said second surface
region can be brought into contact with said surface, and at least
a partial region of said second surface region is provided with an
abrasive material.
17. Method of abrasively treating a working surface with an
abrasive element with an abrasive element according to claim 1,
comprising the following steps: deciding whether a lower or
stronger abrasive effect is to be achieved, and, depending on the
decision: creating a low abrasive effect by pressing said abrasive
element against said working surface while a first pressing force
is applied or creating a stronger abrasive effect by pressing said
abrasive element against said working surface while a second
pressing force is applied, said second pressing force being greater
than said first pressing force.
18. Method according to claim 17, wherein, when said abrasive
element is pressed against said working surface with said second
pressing force, part of said abrasive element is elastically
compressed in such a way that part of a second surface region comes
into contact with said working surface.
19. Method of producing an abrasive element according to claim 1,
comprising the following steps: providing part-elements, in
particular part-elements made of or comprising foam, coating parts
of said surface(s) of said part-element(s) with an adhesive, in
particular with a hot-melt adhesive, applying abrasive material to
said adhesive, and connecting said part-elements to form an
abrasive element.
20. Method of providing an abrasive element, comprising at least
two part-elements of a system according to claim 16, said method
comprising a step of connecting said part-elements to one another.
Description
[0001] The invention relates to an abrasive element, a system
comprising at least two part-elements which can be connected to
form an abrasive element, a method of abrasively treating a working
surface, a method of producing an abrasive element and a method of
providing an abrasive element.
[0002] For the abrasive treatment of working surfaces with abrasive
elements, for instance an abrasive sponge or an abrasive wheel, it
is often desired to use abrasive material with different abrasive
effects. For example, when abrasively removing paint or lacquer
from a surface, it is advantageous to work alternately with a
coarser abrasive grain and a finer abrasive grain, in order in this
way to achieve different abrasive effects. For this purpose, it is
possible to provide a number of abrasive elements that have
different abrasive grains, which can be exchanged as and when
required during work. However, changing the abrasive element is a
laborious and time-consuming affair.
[0003] EP 775 035 has already proposed an abrasive sponge
comprising a foam strip, which has a coating with abrasive material
on several surfaces, it being possible for different abrasive
grains to be applied to different sides. However, as before,
changing over between the different abrasive effects is still
laborious, since the abrasive sponge has to be turned over, which
makes handling more difficult.
[0004] The object of the present invention is therefore to
eliminate the disadvantages of the known art. In particular, it is
intended to provide an abrasive element with which different
abrasive effects can be achieved and with which it is possible to
change between these abrasive effects in an easy way. Furthermore,
it should be possible for the abrasive element to be produced
easily and inexpensively and as flexibly as possible.
[0005] According to the invention, these objects are achieved by an
abrasive element, a system comprising at least two part-elements
which can be connected to form an abrasive element and a method of
abrasively treating a working surface that have the features of the
independent patent claims.
[0006] The abrasive element according to the invention has at least
a first surface region and a second surface region. In this case,
at least part of the first surface region coincides with part of an
enveloping surface of the abrasive element, but at least part of
the second surface region does not coincide with the enveloping
surface of the abrasive element. At least part of the abrasive
element is elastically compressible in such a way that, when the
abrasive element is pressed against a substantially planar surface,
at least part of the second surface region can be brought into
contact with the surface. Furthermore, at least a partial region of
the second surface region is provided with an abrasive
material.
[0007] Here and hereafter, a surface region means part of the outer
surface of the abrasive element. Such a surface region may, in
particular, be substantially planar. Alternatively, it may be
curved, that is to say for instance have the form of part of a
spherical or cylindrical surface. Furthermore, such a surface
region may for its part comprise a number of non-contiguous partial
regions, which are planar or curved. In particular, the second
surface region may extend substantially parallel to the first
surface region.
[0008] The enveloping surface of the abrasive element refers to the
entirety of all the points of the surface that may come into
contact with an imaginary, infinitely large, planar working surface
when the abrasive element makes contact without any forces acting.
This enveloping surface corresponds to the surface of a cloth
stretched around the abrasive element. According to the invention,
part of the surface that does not coincide with part of the
enveloping surface is provided with abrasive material.
[0009] With preference, the elastically compressible part of the
abrasive element can be assigned to part of the first surface
region. In particular, this elastically compressible part is
located at least partially in the vicinity of or underneath the
part of the first surface region. With preference, the elastically
compressible part is compressible in a direction that lies
substantially perpendicular to part of the first surface region to
which the elastically compressible part can be assigned.
[0010] The aforementioned features according to the invention make
it possible when abrasively treating a working surface only to
bring the abrasive material on the partial region of the second
surface region into contact with the working surface when an
adequate pressing force is exerted. Since part of the abrasive
element is elastically compressible, the abrasive element returns
to its original form as soon as the pressing force is reduced.
Consequently, the abrasive material of the second surface region no
longer acts on the working surface as soon as the pressing force
has dropped below a certain value. In this way, it is surprisingly
easy to influence the abrasive effect by adapting the pressing
force, without the abrasive element having to be turned, or even
exchanged, to do so.
[0011] The planarity of the parts of the first surface region has
the effect that a large part of the first surface region can come
into contact with a planar working surface even when there is only
a low pressing force of the abrasive element. With particular
preference, at least two of the non-contiguous partial regions of
the first surface region lie in one plane.
[0012] All materials that have an abrasive effect, such as for
instance aluminium oxide, zirconium corundum, ceramic corundum,
diamond or silicon carbide, may be used as the abrasive material.
The abrasive material is provided on the abrasive element in a way
known per se to a person skilled in the art. For example, it may be
applied with the aid of a binder, such as phenolic resin or
melamine resin, or a hotmelt adhesive.
[0013] According to a preferred embodiment, at least parts of the
first surface region as well are provided with an abrasive
material. With preference, these parts of the first surface region
coincide with an enveloping surface of the abrasive element. In
this way, part of the abrasive material can come into contact with
a planar working surface even when the abrasive element is in
contact with the said working surface without any forces acting.
Consequently, a certain abrasive effect is achieved even without
any pressing force or with only low pressing force. When there is
sufficiently high pressing force, the abrasive material on the
second surface region additionally comes into contact with the
working surface, which can lead to a stronger abrasive effect.
[0014] In a particularly preferred embodiment, the abrasive
materials on the first surface region and on the second surface
region differ from one another. The abrasive materials are also
referred to here as "different" if they merely have different grain
sizes, but do not differ in their basic material. With particular
preference, the abrasive material on the partial region of the
second surface region has a coarser abrasive effect than the
abrasive material on the partial region of the first surface
region. When there is low pressing force of the abrasive element on
a working surface, consequently only the abrasive material with the
finer abrasive effect is used. When there is stronger pressing
force, the compression of part of the abrasive element has the
result that the abrasive material with the coarser abrasive effect
also comes into contact with the working surface. This allows
surprisingly easy control of the desired abrasive effect.
[0015] It goes without saying that the abrasive element may also
have more than two surface regions that can successively be brought
into contact with a working surface as the pressing force
increases. When there are a number of different abrasive materials,
consequently more than two different abrasive effects can also be
achieved.
[0016] In a further preferred embodiment, the abrasive element is
formed as a sponge, pad, sheet or belt. Such sponges are suitable
for instance for preliminary or initial abrasive treatment, in
particular for removing lacquer or paint from surfaces.
[0017] According to a further embodiment, the abrasive element
according to the invention may be formed in a substantially
disc-shaped or cylindrical manner, the first surface region
comprising the surfaces of elevations which protrude at the outer
circumference, and the second surface region comprising depressions
in the radial direction. The elevations consequently form the parts
of the abrasive element that can be assigned to the parts of the
first surface region. In particular, these parts are elastically
compressible in the radial direction.
[0018] Such an abrasive element may be formed for instance as an
abrasive wheel or abrasive cylinder, which can be connected to a
rotating drive. The abrasive element is provided with abrasive
material, at least in the depressions. The construction according
to the invention makes it possible when carrying out abrasive
treatment with the outer circumference of the abrasive element only
to bring the abrasive material that is on the partial region of the
second surface region into contact with the working surface when at
least a predetermined, minimum pressing force is exerted.
[0019] A particularly preferred embodiment provides that at least
parts of the elevations have a lower compressibility than the
remaining part of the abrasive element. In particular, the pressing
force necessary as a minimum to make the abrasive material on the
partial region of the second surface region come into contact with
the working region can be specifically set by choosing the
compressibilities.
[0020] According to another preferred embodiment, the abrasive
element comprises elastically compressible materials, such as for
instance vulcanized or unvulcanized rubber, at least in the region
of the elevations.
[0021] According to a preferred embodiment, at least one of the
elevations may have a bevelled and/or rounded portion. This has the
effect that, during rotating operation of the abrasive element,
impact of the elevation with a working surface that is being worked
is prevented from causing unsteady running or an irregular abrasive
pattern.
[0022] According to a further embodiment, the abrasive element
according to the invention may be formed substantially in a
disc-shaped manner and have at least one substantially circular
base area. The first surface region comprises the surface at least
of an elevation which protrudes from the base area, and the second
surface region is formed partially by the base area. The elevations
consequently form the parts of the abrasive element that can be
assigned to the parts of the first surface region. With preference,
the base area extends substantially in a plane to which parts of
the first surface region are parallel. In particular, the
elevations are elastically compressible perpendicularly to the base
area. Furthermore, the base area may both be contiguous and
comprise regions that are separate from one another.
[0023] In one possible embodiment, the abrasive element comprises
foam, in particular an open-cell foam. When an open-cell foam is
used, it is possible to suck abrasive dust that occurs away through
the abrasive element. With preference, the abrasive element may
have additional extraction openings in the axial direction, through
which abrasive dust can likewise be sucked away.
[0024] According to another preferred embodiment, the abrasive
element comprises elastically compressible materials, such as for
instance vulcanized or unvulcanized rubber, at least in the region
of the elevations.
[0025] Furthermore, it is preferred to provide the side of the
abrasive element that lies opposite the side provided with abrasive
material with means for mechanically connecting the abrasive
element to a drive, for instance part of a Velcro.RTM.-type
fastener system, for example an arrangement of loops and/or hooks.
This makes it possible for the abrasive element to be exchanged
quickly.
[0026] According to a further preferred embodiment of an abrasive
element according to the invention, formed as a sponge, pad or
sheet, the first surface region is formed by the surfaces of at
least one elevation, in particular by prongs or nubs, which are
arranged on the abrasive element; the second surface region is
partially formed by a base area on which the at least one elevation
is arranged. The elevations consequently form the parts of the
abrasive element that can be assigned to the parts of the first
surface region. With preference, the base area extends
substantially in a plane to which parts of the first surface region
are parallel. In particular, the elevations are elastically
compressible perpendicularly to the base area. Furthermore, the
base area may both be contiguous and comprise regions that are
separate from one another.
[0027] It is similarly conceivable for the abrasive element to have
elevations on more than one side, for instance on two opposite
sides. In this case, both the forms and dimensions of these
elevations and the abrasive materials may be different on the
opposite sides.
[0028] According to a further preferred embodiment, the abrasive
element comprises foam. This foam may for instance contain
polyurethane, ethyl vinyl acetate (EVA) or polystyrene and be
open-cell or closed-cell. Such a foam can be produced inexpensively
and can be easily dimensioned and can have an elastic
compressibility that can be predetermined as desired within wide
ranges. It is in this case conceivable for the abrasive element to
comprise foam only in the part in which it is elastically
compressible, in particular in part of the abrasive element that
can be assigned to part of the first surface region.
[0029] According to another preferred embodiment, the abrasive
element comprises elastically compressible materials, such as for
instance vulcanized or unvulcanized rubber, at least in the region
of the elevations.
[0030] According to a further preferred embodiment, the abrasive
element comprises at least two part-elements. These part-elements
may be connected to one another solidly, for instance by adhesive
bonding, or releasably, for instance by inserting and/or pushing
one into the other. With preference, the part-elements are formed
in such a way that they are in contact with one another or can be
brought into contact with one another with positive engagement.
[0031] It is particularly preferred if at least part of the surface
of a first part-element forms part of the first surface region and
at least part of the surface of a second part-elements forms part
of the second surface region. In particular, elevations, such as
for instance nubs or prongs, may be formed by part of only one of
the part-elements. This construction makes a particularly easy
method of production possible for the abrasive element according to
the invention (see below).
[0032] According to a particularly preferred embodiment, at least
two of the part-elements are formed from materials that are
different from one another. In particular, these materials may have
different compressibilities. For example, a first part-element, the
surface of which forms part of the first surface region of the
abrasive element, may have a lower compressibility than a second
part-element, the surface of which forms part of the second surface
region of the abrasive element. When pressing the abrasive element,
consequently only parts of the first part-element are compressed,
whereas the higher compressibility of the second part-element
ensures greater stability of the abrasive element as a whole.
[0033] Furthermore, it is conceivable for the first part-element to
be elastically compressible for instance only in one direction. In
this case, it is preferred that it is elastically compressible in a
direction that extends perpendicularly to the parts of the first
surface region.
[0034] A further aspect of the invention relates to a system
comprising at least two part-elements, at least one of which
comprises a surface which is at least partially provided with an
abrasive material. The system is characterized in that at least two
of the part-elements can be connected to one another, in particular
releasably, in such a way that an abrasive element according to the
invention is obtained. With preference, the part-elements are
formed in such a way that they can be brought into contact with one
another with positive engagement.
[0035] Such a system makes it possible for the user to connect two
or more part-elements to one another according to requirements,
each having the basic materials, dimensions and abrasive materials
that correspond to the application.
[0036] A further aspect of the invention relates to a method of
abrasively treating a working surface with an abrasive element, in
particular with an abrasive element according to the invention. In
the method according to the invention, it is first decided whether
a low abrasive effect or a stronger abrasive effect is to be
achieved. Depending on this decision, a lower abrasive effect is
subsequently achieved by pressing the abrasive element onto the
working surface while a first pressing force is applied, or a
stronger abrasive effect is subsequently achieved by pressing the
abrasive element onto the working surface while a second pressing
force is applied, the second pressing force being greater than the
first pressing force.
[0037] With preference, the method is characterized in that, when
the abrasive element is pressed against the working surface with
the second pressing force, part of the abrasive element is
elastically compressed in such a way that part of a second surface
region comes into contact with the working surface.
[0038] A further aspect of the invention relates to a method of
producing an abrasive element, in particular an abrasive element
according to the invention. The method comprises the following
steps: [0039] providing part-elements, in particular part-elements
made of or comprising foam, coating parts of the surfaces of the
part-elements with an adhesive, in particular with a hotmelt
adhesive, [0040] applying abrasive material to the adhesive, [0041]
connecting the part-elements to form an abrasive element.
[0042] The method according to the invention makes inexpensive and
easy production of an abrasive element according to the invention
possible. With particular preference, only at most one type of
abrasive material is respectively applied to each of the
part-elements. Adhesives, such as for instance hotmelt adhesives,
adhesive films or mechanical connections, such as for instance a
Velcro.RTM.-type fastener system, may be used for example for
connecting the part-elements.
[0043] Furthermore, the invention relates to a method of providing
an abrasive element, in particular one according to the invention.
In particular, the abrasive element comprises at least two
part-elements, in particular part-elements of a system according to
the invention. The method according to the invention comprises
connecting the part-elements, in particular in a releasable
manner.
[0044] The invention is explained in more detail below in exemplary
embodiments and on the basis of the drawings, without restricting
the subject matter of the invention to the embodiments represented.
In the drawings:
[0045] FIG. 1 shows an exploded representation of an abrasive
element according to the invention, comprising two
part-elements,
[0046] FIG. 2 shows an abrasive element according to the invention,
made up of two part-elements,
[0047] FIG. 3a shows a sectional drawing of an abrasive element
according to the invention during the working of a working surface
with low pressing force,
[0048] FIG. 3b shows a sectional drawing of an abrasive element
according to the invention during the working of a working surface
with higher pressing force,
[0049] FIG. 4 shows an abrasive element according to the invention
that is formed in one piece,
[0050] FIG. 5a shows a disc-shaped abrasive element according to
the invention during the working of a working surface with lower
pressing force,
[0051] FIG. 5b shows a disc-shaped abrasive element according to
the invention during the working of a working surface with higher
pressing force,
[0052] FIG. 6 shows a disc-shaped abrasive element according to the
invention with elevations on a circular base area.
[0053] According to FIG. 1, the abrasive element comprises
part-elements 1, 2. The first part-element 1 is formed in a
substantially right-parallelepipedal manner and has on one of its
surfaces 7 a plurality of non-contiguous elevations 3, which are
likewise formed in a right-parallelepipedal manner. At least parts
of the planar surfaces 4 of the elevations 3 may be provided with
an abrasive material, for instance with aluminium oxide. For the
purposes of the invention, the elevations 3 can consequently be
assigned to the surfaces 4. In the depressions between the
elevations 3 there is a planar bearing surface 7, which is formed
parallel to the surfaces 4 of the elevations 3.
[0054] The second part-element 2 is likewise formed in a
substantially right-parallelepipedal manner and has a plurality of
holes 6, which connect two opposite sides 5, 8 to one another. One
side 5 is provided with an abrasive material, which with preference
is coarser than the abrasive material on the surfaces 4 of the
elevations 3. The dimensions of the holes 6 have been made to match
the dimensions of the elevations 3 in such a way that the
part-elements 1, 2 can be connected to one another with positive
engagement (cf. FIG. 2). In particular, the thickness d of the
second part-element is less than the height h of the elevations
3.
[0055] Both part-elements 1, 2 consist of foam, with preference of
polyurethane, ethyl vinyl acetate (EVA) or polystyrene. At least
the elevations 3 of the first part-element 1 are formed in an
elastically compressible manner. With further preference, the
part-elements 1, 2 are respectively formed in one piece and can be
produced by means of known techniques, for [0056] instance by
foaming into a mould. It is possible by methods known per se to set
a compressibility that can be predetermined as desired within wide
ranges. In particular, it is possible to impart inhomogeneous
compressibility to the foam during foaming, so that it has for
instance higher compressibility in the region of the elevations 3.
Alternatively, the part-elements may be produced by cutting or
milling from a foam blank. The abrasive material, which may for
instance be aluminium oxide, is applied to the part-elements 1, 2
with the aid of an adhesive, it being possible for instance for a
hot-melt adhesive to be used.
[0057] With preference, the abrasive element has such dimensions
that it can be comfortably held in one hand. The base areas of the
elevations 3 may have side lengths in the range from a few
millimetres to the total length of the bearing surface 7. In
particular, more than the five elevations 3 that are represented in
FIG. 1 may be present. The surfaces 4 may make up a proportion of
the total bearing surface 7 of between 20% and 80%. The height h of
the elevations 3 may be between a few millimetres and a few
centimetres.
[0058] FIG. 2 shows the put-together abrasive element from FIG. 1.
The side 8 of the second part-element 2 rests on the bearing
surface 7 with positive engagement. The elevations 3 pass through
the holes 6 in the second part-element 2, the dimensions of the
holes 6 having been made to match the dimensions of the elevations
3 in such a way that the side faces 10 of the holes 6 are connected
to the side faces 9 of the elevations 3 with positive engagement.
The surfaces 4 of the elevations 3 protrude beyond the side 5 and
consequently form part of a first surface region which coincides
with an enveloping surface of the overall abrasive element. The
side 5 that is provided with abrasive material forms part of a
second surface region which does not coincide with an enveloping
surface of the overall abrasive element. At least the regions of
the side 5 between the elevations 3 consequently do not come into
contact with a substantially planar surface when the abrasive
element is pressed with a low pressing force. It would likewise be
possible also to provide elevations 3 on the outer edge of the side
5.
[0059] According to one embodiment, the two part-elements 1, 2 are
connected to one another solidly, for instance by adhesive bonding.
Hotmelt adhesives or adhesive films may be used here for instance
as the adhesive means.
[0060] Alternatively, it is possible to provide a system comprising
at least a first part-element 1 and at least a second part-element
2. It is conceivable in this case for instance for the elevations 3
of different first part-elements 1 to have different heights h
and/or the surfaces 4 of different first part-elements 1 to be
provided with different abrasive materials. Such a system makes it
possible for the user to select a first part-element 1 and a second
part-element 2 according to requirements and connect them to one
another in a releasable manner. If the requirements change, one of
the part-elements 1, 2 or both part-elements 1, 2 can therefore be
exchanged. With particular advantage, the releasable connection may
be strengthened by mechanical fastening means, such as for instance
by a Velcro.RTM.-type fastener system.
[0061] FIGS. 3a and 3b illustrate on the basis of sectional
drawings a method of abrasively treating a working surface with an
abrasive element according to the invention. When a first pressing
force of the abrasive element is applied to a working surface 11,
according to FIG. 3a only the surfaces 4 of the elevations 3 come
into contact with the working surface 11. Consequently, only the
low abrasive effect of the surface 4 comes to bear. In the case of
an uncoated surface 4, the abrasive effect may be induced by the
basic material of the first part-element 1 alone, or it may be
induced by an abrasive material applied to it.
[0062] When a second pressing force, which is greater than the
first pressing force, is applied, the elevations 3 according to
FIG. 3b are elastically compressed. In addition to the surfaces 4,
the side 5 that is provided with coarser abrasive material then
also comes into contact with the working surface 11, which results
in a stronger abrasive effect.
[0063] The abrasive element 20 represented in FIG. 4 is formed in
one piece and can be produced by methods known per se, such as for
instance by direct foaming into a mould or by cutting or milling an
already solidified foam. The elevations 3 are formed here as nubs.
For the purposes of the invention, the elevations 3 can
consequently be assigned to the surfaces 4. In the depressions
between the elevations 3 there is a base area 19, which is formed
parallel to the surfaces 4 of the elevations 3.
[0064] At least parts of the base area 19 are provided with an
abrasive material, for instance with aluminium oxide, which may be
applied with the aid of an adhesive, for instance a hotmelt
adhesive. The selective spatial arrangement of the abrasive
materials may be achieved for instance with the aid of
templates.
[0065] In FIGS. 5a and 5b, an abrasive element 12 according to the
invention that is formed substantially in a disc-shaped manner is
represented. Protruding in the radial direction from the outer
circumference 13 are a plurality of elevations 14, the outer faces
15 of which represent a first surface region 4. For the purposes of
the invention, the elevations 14 can consequently be assigned to
the outer faces 15. The depressions 16 located between the
elevations 14 represent a second surface region 5. The depressions
consequently do not coincide with an enveloping surface of the
abrasive element that corresponds to the fully circular outer
circumference 13.
[0066] The outer faces 15 are optionally provided with a fine
abrasive material. The elevations 14 have rounded portions 17. The
depressions 16 are provided with a coarser abrasive material.
[0067] Such an abrasive element 12 consists with preference of
foam, such as for instance polyurethane, ethyl vinyl acetate (EVA)
or polystyrene and can be produced by methods known per se, such as
for instance by direct foaming into a mould or by cutting, milling
or turning an already solidified foam. At least the elevations 14
consist of an elastically compressible material. In particular, the
elevations 14 are elastically compressible in the radial
direction.
[0068] When carrying out abrasive treatment with low pressing
force, according to FIG. 5a only the outer faces 15 come into
contact with a working surface 11 and consequently create a low
abrasive effect. The direction of rotation is denoted here by D. If
the pressing force is increased, the elevations 14 are elastically
compressed according to FIG. 5b. In this way, the depressions 16
likewise come into contact with the working surface 11, so that a
stronger abrasive effect occurs.
[0069] In FIG. 6, a disc-shaped abrasive element 18 according to
the invention, with elevations 3 on a circular base area 19, is
represented. The first surface region is formed by surfaces 4 of
elevations 3. For the purposes of the invention, the elevations 3
can consequently be assigned to the surfaces 4. The second surface
region 5 is formed by the base area 19 and does not coincide with
an enveloping surface of the abrasive element. The base area 19 is
provided with an abrasive material. The surfaces 4 are optionally
provided with a finer abrasive material. The rear side 21 of the
abrasive element is provided with hooks, which form part of a
Velcro.RTM.-type fastener system. With the aid of these hooks, the
abrasive element can be releasably connected to a drive that is not
represented here, on which corresponding loops are located.
Alternatively, loops could also be provided on the rear side 21 of
the abrasive element 18.
[0070] With preference, the abrasive element comprises open-cell
foam. This makes it possible to suck abrasive dust that occurs away
through the abrasive element 18 by means of an extracting device
provided on the drive but not represented here.
[0071] Finally, further embodiments that are not represented here
are possible. For example, the abrasive element according to the
invention may also be formed as abrasive paper or an abrasive
belt.
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