U.S. patent application number 11/017921 was filed with the patent office on 2005-07-14 for tool.
This patent application is currently assigned to August Ruggeberg GmbH & Co. KG. Invention is credited to Huth, Nicolas, Stein, Markus.
Application Number | 20050153640 11/017921 |
Document ID | / |
Family ID | 34585385 |
Filed Date | 2005-07-14 |
United States Patent
Application |
20050153640 |
Kind Code |
A1 |
Stein, Markus ; et
al. |
July 14, 2005 |
Tool
Abstract
In a tool comprising a supporting part and a disk-shaped working
part for machining operation, the supporting part comprises a
supporting face for the working part and a permanent magnet within
the supporting face. The working part comprises a coupling member
of ferromagnetic material which is movable into magnetically
clinging connection with the permanent magnet upon application of a
counterpart supporting face to the supporting face.
Inventors: |
Stein, Markus; (Gummersbach,
DE) ; Huth, Nicolas; (Lindlar, DE) |
Correspondence
Address: |
BROWDY AND NEIMARK, P.L.L.C.
624 NINTH STREET, NW
SUITE 300
WASHINGTON
DC
20001-5303
US
|
Assignee: |
August Ruggeberg GmbH & Co.
KG
Marienheide
DE
|
Family ID: |
34585385 |
Appl. No.: |
11/017921 |
Filed: |
December 22, 2004 |
Current U.S.
Class: |
451/494 |
Current CPC
Class: |
B24D 9/006 20130101;
B24B 45/006 20130101 |
Class at
Publication: |
451/494 |
International
Class: |
B24D 009/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 10, 2004 |
DE |
10 2004 001 546.5 |
Claims
What is claimed is:
1. A tool, comprising a supporting part (1, 1'); a disk-shaped
working part (2, 2') for machining operation; and a common center
line (6); wherein the supporting part (1) has a supporting face (5)
for the working part (2, 2') and, within the supporting face (5),
at least one permanent magnet (14, 14'); wherein the working part
(2, 2') has a counterpart supporting face (15) for the supporting
face (5); and wherein the working part (2, 2') has a coupling
member (19, 19') of ferromagnetic material which is movable into
magnetically clinging connection with the at least one permanent
magnet (14, 14') upon contact of the counterpart supporting face
(15) with the supporting face (5).
2. A tool according to claim 1, wherein the at least one permanent
magnet (14, 14') is disposed in a recess (11, 11') of the
supporting part (1, 1'); and wherein the coupling member (19, 19')
enters into the recess (11, 11').
3. A tool according to claim 2, wherein the recess (11, 11') has a
non-circular cross-sectional shape; and wherein the coupling member
(19, 19') has a non-circular cross-sectional shape that conforms to
the cross-sectional shape of the recess (11, 11').
4. A tool according to claim 3, wherein the recess (11) and the
coupling member (19, 19') have a polygonal cross-sectional
shape.
5. A tool according to claim 4, wherein the recess (11, 11') and
the coupling member (19, 19') have a cross-sectional shape of an
equilateral and equiangular polygon.
6. A tool according to claim 2, wherein the coupling member (19)
has a circular centering shoulder (21) that conforms to the recess
(11).
7. A tool according to claim 1, wherein the supporting part (1, 1')
comprises a supporting casing (3) and a retainer (10, 10') which is
at least sectionally encased by the supporting casing (3).
8. A tool according to claim 7, wherein the supporting casing (3)
consists of plastics.
9. A tool according to claim 7, wherein the retainer (10, 10')
consists of metal.
10. A tool according to claim 1, wherein the supporting part (1,
1') comprises a connection to a rotary drive unit.
11. A tool according to claim 1, wherein the working part (2, 2')
is comprised of abrasive material (16) on a backing (17).
12. A tool according to claim 8, wherein the supporting casing (3)
consists of flexibly resilient material.
13. A tool according to claim 1, wherein
5.ltoreq.D.sub.19/d.sub.19.ltoreq- .100 applies to the ratio that
the greatest diameter (D.sub.19) of the coupling member (19) bears
to the thickness (d.sub.19) thereof.
14. A tool according to claim 1, wherein
1<D.sub.2/D.sub.19.ltoreq.10 applies to the ratio that the
greatest diameter (D.sub.2) of the working part (2) bears to the
greatest diameter (D.sub.19) of the coupling member (19).
15. A tool according to claim 4, wherein the recess (11') and the
coupling member (19') have flanks (12', 20') that are bent
inwards.
16. A tool according to claim 15, wherein respectively adjacent
flanks (12') of the recess (11') and respectively adjacent flanks
(20') of the coupling member (19') are joined to each other by
rounded corners (22, 23).
17. A tool according to claim 15, wherein the flanks (12') of the
recess (11') incline towards each other from the supporting face
(5) into the supporting part (1').
18. A tool according to claim 1, wherein several permanent magnets
(14') are disposed in the supporting part (1').
19. A tool according to claim 18, wherein the permanent magnets
(14') are disposed at equal angular distances and at a distance
from the center line (6).
20. A tool according to claim 11, wherein the working part (2, 2')
is pliable.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a tool comprising a supporting part
and a disk-shaped working part for machining operation.
[0003] 2. Background Art
[0004] Tools of the generic type come in the most various designs,
having a supporting part or base member that is joined to a working
part which is a wearing part. These working parts are for instance
abrasives on a backing, polishing wheels, cleaning wheels which
consist of abrasive embedded in needled nonwoven or felt wheels.
The supporting part and the working part are regularly driven in
rotation. In known designs, a coupling member is mounted on the
side that faces away from the working side, having a female thread
that is screwed on a thread of the supporting part. Attaching the
working part to, and detaching it from, the supporting part is
regularly rather difficult or needs very accurate implementation,
which is in particular stressed by the fact that these working
parts must be replaced frequently after a very short time of use.
Especially in these cases, great stacking heights of the working
parts are occasioned by the considerable height of the coupling
member and female thread.
[0005] EP 1 007 282 B1 teaches to attach abrasive sheet material to
a magnetizable support. To this end, the abrasive material includes
a ferromagnetic metal film. This is not suitable for tools of the
above type.
SUMMARY OF THE INVENTION
[0006] It is an object of the invention to embody a tool of the
generic type in such a way that producing and releasing the
connection between the supporting part and the working part can be
implemented easily and very rapidly.
[0007] According to the invention, this object is attained by the
features wherein the supporting part has a supporting face for the
working part and, within the supporting face, at least one
permanent magnet; wherein the working part has a counterpart
supporting face for the supporting face; and wherein the working
part has a coupling member of ferromagnetic material which is
movable into magnetically clinging connection with the at least one
permanent magnet upon contact of the counterpart supporting face
with the supporting face. The gist of the invention resides in that
the working part includes a coupling member that clings to the
supporting member by magnetic forces. Advantageously, the at least
one permanent magnet is disposed in a recess of the supporting part
and the coupling member enters into the recess.
[0008] In keeping with further embodiments an additional
possibility of positive-fit torque transmission and centering is
created, these embodiments consisting in that the recess has a
non-circular cross-sectional shape; in that the coupling member has
a non-circular cross-sectional shape that conforms to the
cross-sectional shape of the recess; in that the recess and the
coupling member have a polygonal cross-sectional shape; in that the
recess and the coupling member have a cross-sectional shape of an
equilateral and equiangular polygon; in that the coupling member
has a circular centering shoulder that conforms to the recess; in
that the recess and the coupling member have flanks that are bent
inwards; in that respectively adjacent flanks of the recess and
respectively adjacent flanks of the coupling member are joined to
each other by rounded corners; and in that the flanks of the recess
incline towards each other from the supporting face into the
supporting part.
[0009] In keeping with preferred embodiments wherein the supporting
casing consists of flexibly resilient material; and wherein
5.ltoreq.D.sub.19/d.sub.19.ltoreq.100 applies to the ratio that the
greatest diameter D.sub.19 of the coupling member bears to the
thickness d.sub.19 thereof; and wherein
1<D.sub.2/D.sub.19.ltoreq.10 applies to the ratio that the
greatest diameter D.sub.2 of the working part bears to the greatest
diameter D.sub.19 of the coupling member, large-surface,
tensile-strength connection is produced between the coupling member
and permanent magnet without however the working-part stacking
height being substantially affected by the coupling member.
[0010] Further features, advantages and details of the invention
will become apparent from the ensuing description of exemplary
embodiments, taken in conjunction with the drawing.
BRIEF DESCRIPTION OF THE DRAWING
[0011] FIG. 1 is a plan view of the supporting face of a supporting
part of a tool according to the invention;
[0012] FIG. 2 is an explosive cross-sectional view of a tool
according to the invention;
[0013] FIG. 3 is a plan view of the counterpart supporting face of
the working part of the tool;
[0014] FIG. 4 is a sectional explosive view of a coupling member
including a permanent magnet.
[0015] FIG. 5 is a plan view of the supporting face of a supporting
part of another embodiment;
[0016] FIG. 6 is a cross-sectional exploded view of the tool
according to the further embodiment; and
[0017] FIG. 7 is a plan view of the counterpart supporting face of
the working part of the further embodiment.
BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS
[0018] As seen in the drawing, the tool in its fundamental
structure comprises a supporting part 1 in the form of a supporting
plate, and a working part 2. The supporting part 1 has a supporting
casing 3 of flexible plastics which includes an annular supporting
face 5. On the side turned away from the supporting face 5, the
supporting part 1 comprises a threaded hole 7 which is concentric
of the center line 6 and into which to insert a drive shaft 8 of a
tool-actuating unit (not shown) by a corresponding external thread
9. These kinds of tool drive units can be so-called right angle
grinders or spur wheel grinders.
[0019] In the supporting casing 3 on the side of the supporting
face 5, provision is made for a retainer 10 which includes the
threaded hole 7 and, concentrically of the center line 6, a flat
recess 11 of polygonal cross-sectional shape. In the present case,
the recess 11 is formed by flanks 12 of an equilateral and
equiangular polygon, for example a hexagon. A cutout 13 is provided
at each intersection of two adjacent flanks 12.
[0020] A permanent magnet 14 in the form of a flat circular disk is
disposed in the recess 11; it is countersunk as compared to the
supporting face 5 and fixed to the retainer 10 for example by
gluing. Suitably the retainer 10 consists of non-magnetizable
material, but it may also consist of ferromagnetic material or
partially ferromagnetic material, for example in the form of
composite material.
[0021] The real working part 2 also has the shape of a circular
disk, including a counterpart supporting face 15 which comes to
bear against the supporting face 5 upon attachment of the working
part 2 to the supporting part 1. The working part 2 possesses
approximately the diameter or the circumference of the supporting
part 1. In the present case, the working part 2 is comprised of
abrasive material 16 on a backing 17, with the counterpart
supporting face 15 being on the side of the backing 17 that faces
away from the abrasive material 16. Those abrasive materials 16 on
a backing 17 are customarily pliable i.e., flexibly resilient.
[0022] A coupling member 19 of ferromagnetic material is mounted on
the counterpart supporting face 15 concentrically of the center
line 18 of the working part 2. It has the shape of a polygon,
corresponding substantially to that of the recess 11 i.e., in the
present case, it is an equilateral and equiangular hexagon, the
flanks 20 of which, upon placement into the recess 11, bear against
the flanks 12 of the recess 11, this producing a non-rotary
connection between the working part 2 and the supporting part 1.
The coupling member 19 consisting of ferromagnetic material, it is
retained tightly in the recess 11 through magnetic attraction by
the permanent magnet 14. The magnetic forces act in the direction
of the center lines 6, 18. With working parts 2 of the species,
such as abrasive material 16 on a backing 17 or polishing wheels or
cleaning wheels, being set at an angle to the surface that is
worked, the center lines 6, 18 not being perpendicular to the
surface worked, the working parts 2, inclusive of the flexible
supporting casing 3, are bent upon machining operation, which
produces forces that act between the coupling member 19 and the
magnet 14, tending to lift the coupling member 19 off the magnet
14. The magnet 14 must be sufficiently strong to muster these
forces. So it does not only serve to prevent the working part 2
from coming off the supporting part 1.
[0023] On its side turned away from the counterpart supporting face
15, the coupling member 19 comprises a flat, projecting, circular
centering shoulder 21 which is tangent to the six flanks 20 of the
coupling member 19. Upon attachment of the working part 2 to the
supporting part 1, this centering shoulder 21 is inserted first
into the recess 11, thereby producing the centering. Then the
working part 2, together with the coupling member 19, can be
rotated to such an extent that the flanks 20 and the flanks 12
coincide so that the coupling member 19 then bears against the
permanent magnet 14 or is close thereto with only a small air gap
remaining, and the counterpart supporting face 15 bears against the
supporting face 5. The quick-fixing system that acts between the
supporting part 1 and the working part 2 has three jobs, namely:
axial mounting of the working part 2 and attachment thereof to the
supporting part 1 by magnetic forces during a machining operation;
positive-fit torque transmission between the flanks 12 and 20; and
centering upon assembly by the centering shoulder 21 being
insertable between the flanks 12.
[0024] As for the ratio that the diameter D.sub.2 of the working
part 2 bears to the greatest diameter D.sub.19 of the coupling
member 19, the following applies: 1<D.sub.2/D.sub.19.ltoreq.10,
the small value of this ratio applying to particularly small
diameters D.sub.2 of the working part 2 of for instance
approximately 20 mm, whereas the great ratio applies to great
values of D.sub.2, for example in the range of 200 mm or more. As
regards the diameter D.sub.2 found in practice, 20
mm.ltoreq.D.sub.2.ltoreq.250 mm applies.
[0025] Although the described quick-action assembly of the working
part 2 and supporting part 1 is primarily used in rotarily drivable
working parts, it may just as well be used in primarily linearly
drivable working parts, for example in vibrating grinders. With
only a coupling available in this case, the described design serves
as a safeguard against undesired rotation of the working part in
relation to the supporting part.
[0026] As further seen in FIG. 4, the following applies to the
ratio that the greatest diameter D.sub.19 of the coupling member 19
bears to the axial thickness d.sub.19 of the coupling member 19:
5.ltoreq.D.sub.19/d.sub.19.ltoreq.100 and preferably
10.ltoreq.D.sub.19/d.sub.19.ltoreq.30. As regards the ratio that
the greatest diameter D.sub.19 of the coupling member 19 bears to
the diameter D.sub.14 of the permanent magnet,
1<D.sub.19/D.sub.14.ltoreq.- 2 applies.
[0027] The details specified above show that the coupling member 19
is extraordinarily flat as regards its diameter D.sub.19 and its
thickness d.sub.19 on the one hand, and the diameter D.sub.2 of the
working part 2 on the other. Consequently, the stacking height of
the working parts 2 as wearing parts and replacements is affected
by the coupling member 19 only to some minor extent.
[0028] The embodiment according to FIGS. 5 to 7 differs from the
foregoing embodiment only in some details. Therefore, the same
reference numerals are used for identical parts without any renewed
explanation. As far as functionally identical parts are involved
that differ constructionally, the same reference numerals are used,
however provided with a prime.
[0029] Several permanent magnets 14' are provided--six in the
actual case--which are disposed at equal angular distances around
the threaded hole 7 in the retainer 10'. The threaded hole 7 is
open towards the supporting face 5.
[0030] The recess 11' is defined by flanks 12' that form an
approximately equilateral polygon, with the individual flanks 12'
being bent in a direction towards the center line 6 and the meeting
points or intersections where the flanks 12' meet being shaped into
rounded corners 22.
[0031] By adaptation to the modified supporting part 1', the
working part 2' comprises a coupling member 19', the all-round
flanks 20' of which correspond in shape and size to the flanks 12'
of the recess 11' so that, upon snap-engagement of the coupling
member 19' with the recess 11', the flanks 20' rest on the flanks
12'. The flanks 20' too join each other by rounded corners 23 that
match the rounded corners 22. The flanks 12' of the recess 111'
incline towards each other away from the supporting face 5 into the
retainer 10'. The flanks 20' of the coupling member 19' incline
towards each other in the same way so that, upon insertion of the
coupling member 19' into the recess 11', there is not only
non-rotary engagement by positive fit, but also a centering effect
towards the center line 6. A hole 24 is provided in the coupling
member 19', corresponding in size and position to the threaded hole
7, so that the drive shaft 8 of the first exemplary embodiment may
possibly project through the tool--given corresponding conditions
on the side of the tool-actuation unit. As regards the ratios of
diameter and thickness, the explanations of the first embodiment
apply.
[0032] Of course, a number of for instance four permanent magnets
can be provided instead of six permanent magnets 14'. The
supporting face 5 may be a continuous flat surface, however it may
just as well be defined by a plurality of ribs which, not being of
decisive importance, are not shown in detail.
* * * * *