U.S. patent application number 14/787308 was filed with the patent office on 2016-03-17 for abrasive tools and methods of making same.
The applicant listed for this patent is REN S.R.L.. Invention is credited to Nicola FIORE.
Application Number | 20160074999 14/787308 |
Document ID | / |
Family ID | 48877358 |
Filed Date | 2016-03-17 |
United States Patent
Application |
20160074999 |
Kind Code |
A1 |
FIORE; Nicola |
March 17, 2016 |
ABRASIVE TOOLS AND METHODS OF MAKING SAME
Abstract
Abrasive tools of the disposable type applicable to many types
of equipment to sand materials of various types are provided. In
particular, the invention relates to devices using rotating
abrasive discs for sanding machines, which include a plurality of
flexible abrasive discs open at a radial cut and arranged in an
overlapping and staggered configuration such as to define an
abrasive, lamellar-like work surface with overlapping flaps,
wherein each flap is formed of a protruding portion of an abrasive
disc. Methods of making such abrasive tools are also provided.
Inventors: |
FIORE; Nicola; (Parabiago,
MILANO, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
REN S.R.L. |
Milano |
|
IT |
|
|
Family ID: |
48877358 |
Appl. No.: |
14/787308 |
Filed: |
July 9, 2013 |
PCT Filed: |
July 9, 2013 |
PCT NO: |
PCT/IB2013/055639 |
371 Date: |
October 27, 2015 |
Current U.S.
Class: |
451/56 ; 451/529;
51/307 |
Current CPC
Class: |
B24D 13/16 20130101;
B24D 18/0045 20130101 |
International
Class: |
B24D 13/16 20060101
B24D013/16; B24D 18/00 20060101 B24D018/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 7, 2013 |
IT |
MI2013A000734 |
Claims
1-14. (canceled)
15. An abrasive tool for sanding machines, comprising a plurality
of flexible abrasive discs open at a radial cut and arranged in an
overlapping and staggered configuration such as to define an
abrasive, lamellar-like work surface with overlapping flaps,
wherein each flap comprises a protruding portion of an abrasive
disc.
16. The abrasive tool of claim 15, wherein each abrasive disc
comprises a central hole from which a plurality of slots extend in
a spoke pattern, so as to form tongues positioned around the
hole.
17. The abrasive tool of claim 15, wherein said radial cut extends
between the peripheral rim of a disc and its central hole.
18. The abrasive tool of claim 15, wherein said flexible abrasive
discs comprise a backing having a binding agent to which a suitable
abrasive powder adheres.
19. The abrasive tool of claim 18, wherein said backing comprises
paper, preferably weighing 70 to 300 g/m.sup.2, or canvas or
canvas/paper; or said backing is made from semi-rigid plastic
material or a thin and flexible sheet of metal, such as
aluminium.
20. The abrasive tool of claim 18, wherein said backing comprises
the male or female element of a velcro fastening system on the
opposite side to the abrasive side, so as to permit its removable
attachment to the polishing pad of a sander comprising the
complementary velcro element.
21. The abrasive tool of claim 20, wherein said abrasive discs are
replaced by half-moon abrasive elements, each abrasive half-moon
element comprising an abrasive surface and an opposite velcro
surface, of the female or male type, such velcro surface being
destined to cling to a velcro surface of the complementary type
attached to the polishing pad of a sander.
22. The abrasive tool of claim 18, wherein said abrasive powder is
selected from the group consisting of: diamond, corundum, quartz,
silica, pumice, sandstone, emery, garnet and any combination
thereof; or a synthetic powder selected from the group consisting
of: aluminium, chrome, iron, zirconium oxides, boron nitride,
silicon carbide, glass, boron carbide, ceramic-coated aluminium
oxide and any combination thereof.
23. The abrasive tool of claim 18, wherein said binding agent is
selected from the group consisting of: natural glues, ureic resins
and phenolic resins.
24. The abrasive tool of claim 15, wherein said abrasive disc or
said half-moon abrasive element comprises a plurality of through
holes on its surface.
25. The abrasive tool of claim 15, wherein the abrasive discs or
abrasive half-moon elements have a different grain, preferably
increasing or decreasing in succession.
26. The abrasive tool of claim 15, wherein the abrasive discs the
same or different from each other, have an abrasive surface which
has separate portions of a different grain.
27. A Method of making an abrasive tool comprising the following
steps: providing a plurality of flexible abrasive discs having a
central hole and a radial cut which extends from the peripheral rim
of a disc and its central hole, said radial cut having a first and
a second rim; stacking said abrasive discs, aligning the respective
radial cuts; bending said abrasive discs together so as to bring
the first rims, destined to form the working rims of the tool, into
an offset position from the opposite second rims; rotating the
lowest disc in the stack around an axis perpendicular to the disc
and passing through the centre, then in succession rotating all the
other discs from the bottom to the top, so as to achieve a
staggered configuration which gives rise to the lamellar-like
abrasive work surface.
28. A method of renewing the worn abrasive work surface of an
abrasive tool, comprising the following steps: removing the worn
flaps or just the portion thereof comprising the edge; and if
necessary, rotating the lowest disc in the stack around an axis
perpendicular to the disc and passing through the centre, then in
succession rotating all the other discs from the bottom to the top,
so as to achieve a staggered configuration.
Description
[0001] The present invention relates to an abrasive tool of the
disposable type applicable to equipment, both professional,
industrial and for hobbies, to sand materials of various types
having rough surfaces. In particular, the invention relates to a
device using rotating abrasive discs.
[0002] The sanding of rough or in any case uneven surfaces is a
procedure widely applied throughout various sectors, both crafts
and industrial, such as construction, carpentry, and the processing
of hard materials. Depending on the extension of the surface to be
sanded, manual or portable roller sanders are used. The latter are
normally used to sand floors, while the former are used to sand
small surfaces and often for private use (hobbies). Vice versa,
large bench sanders are used to sand untreated manufactured goods
for example made from stone, resin or lacquered.
[0003] The abrasive surfaces used for sanding are of different
types, both natural and synthetic. For example diamond, corundum,
silica, quartz, pumice, sandstone or various synthetic oxides such
as aluminium, chrome, iron, glass oxides and so forth are used. In
all cases the chosen material is ground so as to obtain a
predefined grain size which also depends on the type of sanding
desired, it is then combined with a binding agent to make it adhere
to a backing or modelled, with or without the binding agent, to
form the tool, to mention just some of the more conventional
methods.
[0004] The sanding of an untreated surface is usually conducted in
a series of stages. Levelling and roughing are usually the first
steps, followed by finishing and polishing after filling in any
cracks or pores. For each of these steps an abrasive surface having
a different grain is used, that is to say in which abrasive powder
material has a specific grain size: the biggest grain is used to
roughly sand the surface, in that it permits removal of the excess
material more easily but is unable to provide a surface finish; the
finer grain instead makes it possible to achieve a good finish as
far as sanding the surface but cannot be used for the first rough
sanding step. For certain types of material, in particular stone
materials, there may be as many as ten subsequent steps starting
from an abrasive surface with a coarser grain and gradually moving
to a finer grain.
[0005] One type of abrasive tool used in particular for manual
sanders is that of the so-called abrasive flap or lamellar discs.
An abrasive disc of this type, shown by way of example in FIG. 1,
is composed of a disc-shaped backing in essentially rigid material
such as plastic or aluminium, onto which a plurality of abrasive
fins of the desired grain are glued. The fins are arranged so as to
partially overlap each other like roof tiles, which allows them to
expose a sharp edge contributing greatly to the sanding action,
this being the point in which the greater pressure is exerted by
the operator during use. Lamellar flap discs have various
advantages compared to traditional abrasive discs composed of a
single disc of abrasive material, such as longer duration and high
quality performance, but have the drawback of being expensive,
having a rigid structure and entailing an excessive waste of
material at the moment of their disposal, especially of the rigid
support to which the lamellar flaps are glued.
[0006] The purpose of the present invention is therefore to make
available an abrasive tool for sanding machines which resolves the
drawbacks of the prior art and in particular which is flexible,
lasting, of limited cost and which permits high quality
performance.
[0007] Such problem is resolved by an abrasive tool as delineated
in the appended claims, the definitions of which form an integral
part of this description.
[0008] One object of the invention is therefore a flexible abrasive
tool of the lamellar-like type re-adaptable according to the wear
of the abrasive surface.
[0009] Another object of the invention is a constructionally simple
abrasive tool of the lamellar-like type of a contained cost.
[0010] One further object of the invention is therefore a flexible
abrasive tool of the lamellar-like type having a variable grain
abrasive work surface.
[0011] Further characteristics and advantages of the present
invention will be more clearly comprehensible from the description
given below of as preferred and non-limiting embodiment with
reference to the appended drawings, wherein:
[0012] FIG. 1 is a plan view of an abrasive lamellar flap disc
according to the prior art;
[0013] FIG. 2 is a perspective transparent view of an abrasive tool
according to the invention;
[0014] FIG. 3 is a plan view of an abrasive disc of the tool
according to the invention;
[0015] FIG. 4 is a plan view of the abrasive disc in FIG. 3
according to a different embodiment of the invention;
[0016] FIG. 5 is an exploded side view of the abrasive tool of the
invention fitted onto a manual sander;
[0017] FIGS. 6A and 6B show the sequence of operations needed to
predispose the abrasive tool according to the invention;
[0018] FIG. 7 is a perspective transparent view of an abrasive tool
according to a different embodiment of the invention.
[0019] With reference to the figures, the abrasive tool which the
invention relates to, globally denoted by reference numeral 1,
comprises a plurality of flexible abrasive discs 2, open at a
radial cut 3 and arranged in an overlapping and staggered
configuration such as to define an abrasive, lamellar-like work
surface 4 with overlapping flaps, wherein each flap 5 is formed of
a protruding portion of an abrasive disc 2.
[0020] The term "abrasive disc" is understood to mean both a
correctly named disc of a circular shape and any other disc, even
of a polygonal shape, suitable for use in sanding machines with
rotating elements.
[0021] The term "lamellar-like" means a configuration in which a
plurality of flaps 5 are positioned so as to create a partially
overlapping lamellar structure, typical of the abrasive lamellar
discs shown by way of example in FIG. 1.
[0022] As shown in FIG. 3, each abrasive disc 2 of the plurality of
discs comprises a central hole 7 from which a plurality of slots
arranged in a spoke pattern depart, so as to form flaps 9
positioned around the hole 7.
[0023] The abrasive disc 2 further comprises said radial cut 3
which extends from the peripheral rim 6 of the disc to the central
hole 7.
[0024] The abrasive disc 2 is flexible. An abrasive disc suitable
for the purposes of the present invention is any one of the
conventional flexible abrasive discs.
[0025] The flexible abrasive discs are characterised by a backing
to which a suitable abrasive powder adheres by means of a binding
agent.
[0026] For example, a disc having a paper backing, typically
weighing from 70 to 300 g/m.sup.2 or a canvas or canvas/paper
backing may be used. Alternatively the backing may be made from
semi-rigid plastic material or even a thin and flexible sheet of
metal, such as aluminium. In certain embodiments, the backing
comprises the male or female element of a velcro fastening system
on the opposite side to the abrasive side, so as to permit its
removable attachment to the polishing pad of a sander which will in
turn comprise the complementary velcro element.
[0027] The abrasive powder may be selected from among those
commonly used in the sector depending on the type of surface to be
sanded and the desired finish. For example a natural abrasive
powder of diamond, corundum, quartz silica, pumice, sandstone,
emery, garnet or a synthetic powder of aluminium, chrome, iron,
zirconium oxides, boron nitride, silicon carbide, glass, boron
carbide, ceramic-coated aluminium oxide may be used. The grain may
be chosen from among those commonly used for the varying degrees of
finish required, for example for artificial corundum and for
silicon carbide this may be between 8 and 240 degrees, as defined
in the UNI table 3898. A small number corresponds to a coarse
grain, suitable for rough sanding, while the higher numbers
identify an increasingly finer grain.
[0028] The binding agent may be chosen from among those widely used
in the sector, such as natural glues, ureic resins and phenolic
resins.
[0029] The abrasive powder on the backing may have a closed
coating, that is to say with a high density of abrasive granules,
suitable for hard materials and for a high quality finish; or an
open coating namely with a low density of abrasive granules,
suitable for ensuring high resistance to clogging. In addition, the
abrasive disc may comprise additives, such as anti-clogging
additives (zinc stearate) or anti-static products.
[0030] In certain embodiments, as shown in FIG. 4, the abrasive
disc 102 comprises a plurality of through holes 10 on its surface,
the function of which is to assist the removal of the dust formed
during sanding.
[0031] FIGS. 6A and 6B show the sequence in which the abrasive tool
1 is assembled starting from a plurality of abrasive discs 2, 102.
First of all, the discs are stacked, aligning the respective radial
cuts 3. The discs are then bent together so as to bring the rims
11, destined to form the working rims of the tool, into a position
offset from the opposite rims 12, which instead remain hidden under
the abrasive surface 4 (FIG. 6A). At this point, the bottom disc of
the stack is rotated in the direction of the arrow, around an axis
perpendicular to the disc and passing through the centre, then in
succession all the other discs from the bottom to the top, so as to
achieve a staggered configuration which gives rise to the
lamellar-like abrasive work surface 4 (FIG. 6b).
[0032] The number of abrasive discs 2 composing the abrasive tool 1
may vary from a minimum of two discs to a dozen or more. By
increasing the number of discs, the flap 5, that is the portion of
disc emerging and thus exposed to globally form the abrasive work
surface 4, becomes increasingly smaller. In addition, as the number
of disks increases, the lamellar-like configuration of the tool
will comprise a large number of flaps 5, each of which presenting a
sharp edge 11 which constitutes the part of greatest friction and
which during use works harder and is therefore subject to greatest
wear.
[0033] The abrasive tool 1 may then be mounted on a polishing pad
13 of a sander 14 (shown schematically in FIG. 5) by means of a
suitable stop screw 15. The pad 13 typically has a central
depressed area 16 with a hole. The stop screw 15 passes through the
central hole 7 of the abrasive tool and through the hole of the pad
13 before screwing onto the rotating plate 17 of the sander 14.
This way, the head of the stop screw 15 is positioned under the
abrasive surface 4 which is instead supported by the outer portion
of the pad 13, and does not therefore interfere with the surface to
be sanded. This type of attachment of the tool to the sander is
permitted by the flexibility of the material with which the
abrasive tool 2 is made and by the presence of the slots 8 which
form the tongues 9 suitable to be bent downward and clamped between
the head of the stop screw 15 and the surface of the central
depressed area 16 of the polishing pad 13.
[0034] Other methods of attachment of the abrasive tool according
to the invention to the sander may however also be provided for.
For example the velcro system described above makes it possible to
rapidly and effectively attach the abrasive tool to a pad 13.
[0035] When the abrasive surface 4, and in particular the rims 11
of the discs 2, 102 are worn, it is possible to remove, for example
by cutting with scissors or another cutting tool, the worn flaps 5
or just the portion thereof comprising the edge 11, and if
necessary repeating the operation of rotating the single discs
shown in FIG. 6B, maintaining the initial staggering. This way, new
portions of disc which will form the new flaps 5 are uncovered. It
is thus possible to exploit to the most the abrasive surface of
each disc 2, 102, gradually renewing the abrasive work surface 4.
The single discs 2, 102 may also have radial weakening lines or in
any case radial lines traced on them to facilitate the removal of
the worn segment and keep a straight edge 11.
[0036] In some embodiments the discs 2, 102 which form the abrasive
tool 1 have the same grain.
[0037] In other embodiments, abrasive discs of a different grain 2,
102 are used, in particular arranging the different discs in
succession with an increasing (or decreasing) grain. This way it is
possible to obtain the sanding and finishing of a surface in
drastically shorter times than with the conventional technology
which provides for subsequent passages with disks of an
increasingly finer grain.
[0038] In yet other embodiments, the abrasive discs 2, 102, the
same or different from each other, have a so-called multi-abrasive
surface, as disclosed in the prior Italian patent application no.
MI2011A000850 (filed on 16 May 2011) by the same applicant.
"Multi-abrasive surface" means an abrasive surface which has
separate portions having a different grain. The arrangement of such
portions on the surface of the disc may be according to various
criteria but in particular those of creating a path in which the
grain gradually increases or decreases. Arrangements in spots,
concentric circles or spirals are for example possible. Reference
is in any case made to the aforementioned patent application for a
clearer understanding of the structure of such discs utilisable for
the purposes of the present invention.
[0039] In a different embodiment, shown in FIG. 7, the abrasive
tool 201 comprises a plurality of half-moon abrasive elements 202
in place of the abrasive discs 2, 102. Such half-moon element 202
may be made from the abrasive discs 2, 102 by cutting along the
entire diameter of the disc.
[0040] Each half-moon element 202 comprises an abrasive surface 204
and an opposite velcro surface 240, of the female or male type,
such surface 240 being destined to cling to a velcro surface of the
complementary type attached to the polishing pad 13 of a sander 14.
The plurality of half-moon abrasive elements 202 are arranged so
that the single elements are staggered as shown in FIG. 7 (only
three abrasive elements 202 have been shown for sake of clarity),
revealing the flaps 205, and the assembly thus composed is applied
to the velcro on the polishing pad 13.
[0041] This embodiment has the advantage of making the fitting of
the tool more practical in that the underside, that is to say the
velcro surface, would make the reciprocal sliding of the whole
discs difficult.
[0042] The abrasive tool 1 according to the present invention has
many advantages.
[0043] First of all the abrasive tool according to the invention
makes it possible to create a lamellar-like configuration by means
of a simple and economical process. It is not in fact necessary to
predispose the rigid backing in plastic or metal to which the flaps
of conventional lamellar discs are glued. This translates not only
into reduced production costs, but also into a reduced quantity of
waste material at the end of the tool's life.
[0044] Moreover, the tool according to the invention combines the
flexibility of conventional flexible discs with the typical
characteristics of a lamellar configuration, something which is
instead absent in the flap discs of the prior art.
[0045] The possibility of reciprocally rotating the various
abrasive discs composing the tool makes it possible to remove the
worn abrasive surface, increasing the life of the tool and making
it possible to practically use almost the entire surface of each
disc.
[0046] The abrasive discs composing the tool may have a different
grain from one another or have a variable grain surface, as said
above, which reduces the number of sanding cycles when operations
are in progress.
[0047] It is evident that only one particular embodiment of the
present invention has been described, so that a person skilled in
the art may make all the changes needed to adapt it to specific
conditions. The abrasive tool 1 according to the invention may be
fitted onto various types of sanders, such as rotary sanders,
orbital sanders, roto-orbital, planetary, if necessary after
suitable adjustments either structural or dimensional of the
various types of machine used, adaptations which fall within the
normal skills of a person skilled in the art and which do not
depart from the object of the present invention as defined in the
appended claims.
* * * * *