AU2007234477A1

AU2007234477A1 - Improvements relating to a quick-release coupling for attaching an abrasive disc to a grinding apparatus and an abrasive disc for use with such a coupling

Info

Publication number: AU2007234477A1
Application number: AU2007234477A
Authority: AU
Inventors: Mark Allen
Original assignee: RICHMOND IND Ltd
Current assignee: RICHMOND INDUSTRIES Ltd
Priority date: 2006-11-14
Filing date: 2007-11-14
Publication date: 2008-05-29
Also published as: AU2007100255B4; NZ551304A; AU2007100255A4

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant(s): Richmond Industries Limited Invention Title: Improvements relating to a quick-release coupling for attaching an abrasive disc to a grinding apparatus and an abrasive disc for use with such a coupling The following statement is a full description of this invention, including the best method for performing it known to me/us: 2 O IMPROVEMENTS RELATING TO A QUICK-RELEASE COUPLING FOR ATTACHING AN ABRASIVE DISC TO A GRINDING APPARATUS AND AN O ARBASIVE DISC FOR USE WITH SUCH A COUPLING This invention relates to a quick-release coupling for attaching an abrasive disc to a grinding apparatus. The invention also relates to an abrasive disc that can be attached to a grinding apparatus using such a coupling.

(cN As used throughout the specification, the term "grinding apparatus" is intended to refer to any device in which, (1 during operation, a rotating disc is placed in contact with the surface of an object. The rotating disc will be referred to throughout the specification as an "abrasive disc" but could be a polishing disc. The term "grinding apparatus" includes but is not limited to: bench or pedestal grinders; handheld grinders, including an angle grinder or a straight grinder; portable grinders, including an asphalt grinder or a floor grinder; and stationary grinders, including a cylindrical grinder, surface grinder, a tool and cutter grinder; or a floor polisher.

BACKGROUND TO THE INVENTION Abrasive discs used in a grinding apparatus can require frequent replacement due to wear on the disc as a result of friction between the disc and the workpiece.

Furthermore, the disc must be securely attached to the apparatus to ensure that the disc is not released from the driveshaft during operation of the apparatus.

The time taken to detach a securely attached disc from a grinding apparatus and to securely attach a replacement disc can be lengthy. For example, it is known in the art to use a nut to secure an abrasive disc to a grinding apparatus. However, a nut can be over-tightened and N \Melboume\Cases\Patent\7400-74999\P7480S AUJSpecis\P74805AU GH Sped as fileddoc 14/11/07 3 consequently difficult to remove.

0 Quick-release couplings to attach an abrasive disc to a Zgrinding apparatus are known in the art, for example, United States Patent No. 6,530,828 describes an abrasive disc that has an undercut, spirally shaped edge contour for engagement with a suitable counter-contour on an accommodating carrier.

c, However, there are a number of difficulties and/or O disadvantages associated with the couplings of the prior 1 art, including that the coupling does not allow the abrasive disc to be repositioned when some parts of the disc are more worn than other parts of the disc.

It is an object of the invention to provide a quickrelease coupling for attaching an abrasive disc to a grinding apparatus that will overcome at least some of the abovementioned difficulties and/or disadvantages, or that will at least provide the public with a useful choice.

It is also an object of the invention to provide an abrasive disc for use with such a coupling that will overcome at least some of the abovementioned difficulties and/or disadvantages, or that will at least provide the public with a useful choice.

SUMMARY OF THE INVENTION According to a first aspect of the invention, there is provided a coupling for attaching an abrasive disc to a grinding apparatus and adapted for rotation about a central axis, the coupling comprising a first major face which will engage a drive means and a second major face which comprises a mounting surface to cooperate with a contact surface of the disc, the coupling being adapted to engage the disc along a mounting plane at the interface N:\Mclboumc\Cs\atent\74OO-74999\P7485.AU\Specis\P74805AU GH Speci as fileddoc 14/11/07 4 O between the mounting surface and the contact surface, the mounting surface having one or more drive elements that are O each sized to cooperate with a corresponding drive element on the mounting surface and to position the disc on the coupling, the first drive element in each cooperating pair being a protrusion from one of the surfaces and the second drive element in each cooperating pair being a recess in the other surface, the protrusion capable of being received Sand retained in the recess, the or each drive element on the mounting surface having a driving face substantially Sperpendicular to the mounting plane and the or each drive (1 element on the contact surface having a drivable face substantially perpendicular to the mounting plane, whereby when the disc is mounted on the coupling at least a substantial portion of the or each driving face contacts at least a substantial portion of the corresponding drivable face to provide a driving force in the direction of rotation.

Expediently the mounting surface has two drive elements that are generally diametrically opposite on the surface and equally spaced from the central axis.

In one preferred embodiment, the driving faces of the drive elements on the mounting surface are generally parallel and equally offset from the diameter of the coupling and the drivable faces of the drive elements on the contact surface are generally parallel and equally offset from the diameter of the disc.

The pair of drive elements or each pair of drive elements may consist of a shaped protrusion and a correspondingly shaped recess, for example, a fin-shaped protrusion and a correspondingly fin-shaped recess.

In one preferred embodiment, the second major face is substantially parallel to the first major face.

N:\Melboum\Cus'\Patcnt\4000-74999\P74805 AU\Specis\P74805.AU GH Speci as filed.doc 14/11/07 Preferably the coupling includes an aperture that passes O between the centre of the first major face and the centre of the second major face. More preferably the aperture is cylindrical.

The coupling may include a centrally located extension from the second major face of the coupling. Preferably Sthe extension is cylindrical. In a further preferred embodiment, the extension is a collar around the aperture 8 that passes between the centre of the first major face and c1 the centre of the second major face.

Preferably the shape of the first major face and the second major face is annular, circular, square, or a regular polygon. More preferably the shape of the first major face and the second major face is annular.

According to a second aspect of the invention, there is provided an abrasive disc mountable on the drive coupling of a grinding apparatus and adapted for rotation about a central axis, the disc comprising a rear face and an operative front face, the rear face presenting a contact surface to cooperate with a mounting surface of the coupling, the disc being adapted to engage the coupling along a mounting plane at the interface between the contact surface and the mounting surface, the contact surface having one or more drive elements that are each sized to cooperate with a corresponding drive element on the mounting surface and to position the disc on the coupling, the first drive element in each cooperating pair being a protrusion from one of the surfaces and the second drive element in each cooperating pair being a recess in the other surface, the protrusion capable of being received and retained in the recess, the or each drive element on the mounting surface having a driving face substantially perpendicular to the mounting plane and the or each drive N:\Meloume\Cases\Paent74OOO-74999\P748S AU'Specis\P74SOS.AU GH Spei as lileddoc 14/11/07 6 O element on the contact surface having a drivable face substantially perpendicular to the mounting plane, whereby O when the disc is mounted on the coupling at least a substantial portion of the or each driving face contacts at least a substantial portion of the corresponding drivable face to provide a driving force in the direction of rotation.

SExpediently the contact surface has two drive elements that are generally diametrically opposite on the surface and Sequally spaced from the central axis.

In one preferred embodiment, the drivable faces of the drive elements on the contact surface are generally parallel and equally offset from the diameter of the disc and the driving faces of the drive elements on the mounting surface are generally parallel and equally offset from the diameter of the coupling.

In one preferred embodiment, the rear face is substantially parallel to the front face.

Preferably the abrasive disc includes an aperture that passes between the centre of the front face and the centre of the rear face. More preferably the aperture is cylindrical.

Preferably the shape of the front face and the rear face is annular, circular, square, or a regular polygon. More preferably the shape of the front face and the rear face is annular.

N \Mclboumc\Cascs\Patent\74000-74999\P74805 ALNSpecis\P7480S.AU GH Speci as fileddoc 14/11/07 7 SAccording to a third aspect of the invention, there is provided a method of mounting the abovementioned abrasive O disc to the abovementioned coupling wherein the provision of cooperating drive elements facilitates mounting of the disc in a desired position on the coupling.

In a preferred embodiment, more than one pair of cooperating drive elements are spread equally apart to Sallow mounting in more than one selected position.

SIn one embodiment, an axially mounted locking nut is used C( to secure the abrasive disc in position on the coupling.

The cooperation of the protrusion with the corresponding recess in each pair of drive elements preventing rotation of the abrasive disc relative to the coupling. In some circumstances, it may be necessary to supplement the axially mounted locking nut with a number of radially dispersed mounting bolts.

According to a fourth aspect of the invention, there is provided a grinding apparatus including the abovementioned coupling. The abovementioned abrasive disc may be attached to the coupling.

DETAILED DESCRIPTION OF THE INVENTION A preferred embodiment of the quick-release coupling and the abrasive disc will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of the second major face of the coupling.

Figure 2 is a plan view of the second major face of the coupling.

Figure 3 is a side view of the coupling.

Figure 4 is a plan view of the rear face of the abrasive N:\Melbourne\CLses\Patent\74000-7499\P7480S.A\Specis\P748O5.AU GH Speci as filed doc 14/11/07 8 disc.

Figure 5 is a plan view of the operative front face of the O abrasive disc Figure 6 is an exploded side view of the coupling, a drive means, the abrasive disc, a locking nut, and a spanner.

The quick-release coupling 1 is designed to allow the abrasive disc 2 to be quickly and securely attached to or Sdetached from a drive means 3 in a grinding apparatus.

SAs used throughout the specification, the term "drive N means" is intended to refer to any device in a grinding apparatus that can be rotated by an engine or motor. In the preferred embodiment, the drive means 3 comprises a driveshaft 4 and a flexible coupling 5 to which the quickrelease coupling 1 can be attached. However, in another embodiment the quick-release coupling can be formed integrally with the drive means.

The quick-release coupling 1 is adapted for rotation about a central axis 9. The abrasive disc 2 is also adapted for rotation about a central axis 11.

The quick-release coupling 1 has two major faces. The first major face 6 is engaged with and is rotationally driven by the drive means 3. The second major face 7 is substantially parallel to the first major face 6 and comprises a mounting surface 7 to cooperate with a contact surface 31 for the abrasive disc 2.

The abrasive disc 2 has a rear face and an operative front face, the rear face of which presents a contact surface 31 for the quick-release coupling 1.

The quick-release coupling 1 is adapted to engage the abrasive disc 2 along a mounting plane at the interface between the mounting surface 7 and the contact surface 31.

N \Melboure\Cajes\Patent74OOO-74999\P748OS AU\Specis\P74805.AU GH Spoci as fileddoc 14/11/07 9 The quick-release coupling 1 includes a cylindrical O aperture 9 that passes between the centre of the first major face 6 and the centre of the second major face 7 of the quick-release coupling i. The aperture 9 is designed to engage with a cylindrical extension 8 from the flexible coupling 5 to assist in mounting the quick-release coupling 1 to the flexible coupling (Ni The quick-release coupling 1 also includes a centrally O located cylindrical collar 10 around the circumference of (1 the aperture 9 on the second major face 7. The collar is designed to engage with a centrally located cylindrical aperture 11 in the abrasive disc 2 to assist in mounting the abrasive disc 2 to the quick-release coupling 1. The collar 10 has an external screw thread that enables a locking nut 25 with an internal screw thread to be screwed onto the collar 10 with a spanner 26. The locking nut attaches the abrasive disc 2 to the quick-release coupling 1.

The quick-release coupling 1 has three bolt holes 16, 17, 18 that pass through the quick-release coupling 1 between the first major face 6 and the second major face 7.

Similarly, the abrasive disc 2 has six bolt holes 19, 21, 22, 23, 24 that pass through the abrasive disc 2 between the operative front face and the rear face. It will be clear that both the quick-release coupling 1 and the abrasive disc 2 could contain a different number of bolt holes from those of the preferred embodiment.

However, it is preferred that the abrasive disc 2 contains more bolt holes than the quick-release coupling i.

Depending upon loading and use, a high speed quick-release coupling 1 may use only the collar 10 to retain the abrasive disc 2 onto the quick-release coupling i, the cooperating fin-shaped projections 12, 13 and recesses 14, N \Mlcboumc\Cases\Patenit7400-74999\P74805.ALPSpecis\P7485 AU GH Spcci as filed doc 14/11/07 0 O 15 described below restraining the abrasive disc 2 from rotation relative to the quick-release coupling 1. In O this alternative embodiment, bolts do not pass between the bolt holes 16, 17, 18 in the quick-release coupling 1 and the bolt holes 19, 20, 21, 22, 23, 24 in the abrasive disc 2 and, as such, the bolt holes 19, 20, 21, 22, 23, 24 in the abrasive disc 2 need not be present.

SThe mounting surface on the second major face 7 of the quick-release coupling 1 comprises two drive elements, namely two fin-shaped projections 12, 13 that each extend (1 from diametrically opposite sides of the collar 10 and are equally spaced from the central axis 9. The two finshaped projections 12, 13 are each sized to cooperate with two corresponding drive elements to position the disc on the coupling, namely, two fin-shaped recesses 14, 15 that each extend from diametrically opposite sides of the aperture 11 in the contact surface of the abrasive disc 2 and are equally spaced from the central axis 11. The protrusions 12, 13 are capable of being received and retained in the recesses 14, When the fin-shaped projections 12, 13 are engaged with the fin-shaped recesses 14, 15, the three bolt holes 16, 17, 18 in the quick-release coupling 1 are aligned with three of the six bolt holes 19, 20, 21, 22, 23, 24 in the abrasive disc 2. Bolts that are inserted into the aligned bolt holes are also able to be inserted into bolt holes in the flexible coupling 5 and therefore attach the quickrelease coupling 1 and the abrasive disc 2 to the flexible coupling When the operator changes the abrasive disc 2, he or she can align the bolt holes in the abrasive disc 2 and the quick-release coupling 1 by simply rotating the abrasive disc 2 about the quick-release coupling 1 until the finshaped projections 12, 13 are engaged with the N \AMelboume\Caes\Paen\74DDD-74999\P748O ALASpccis\P74805 AU GH Speci s fileddoc 14/11/07 11 O corresponding fin-shaped recesses 14, 15. This is much easier for the operator to do in the often hot and dusty O environment in which a grinding apparatus is used than spending time aligning the bolt holes by sight.

A consequence of operating a grinding apparatus is that some parts of an abrasive disc 2 can be more worn than other parts of the same disc.

An advantage of positioning the fin-shaped projections 12, S13 on diametrically opposite sides of the collar 10 on the C( quick-release coupling 1 and the fin-shaped recesses 14, on diametrically opposite sides of the aperture 9 on the abrasive disc 2 is that rather than replacing the abrasive disc 2 when one half of the disc is more worn than the other half, the abrasive disc 2 can be removed from the quick-release coupling 1, rotated 180 degrees, and reattached to the quick-release coupling i. This can increase the useful life of the abrasive disc 2.

Although in the preferred embodiment the projections 12, 13 on the quick-release coupling 1 and the recesses 14, on the abrasive disc 2 are fin-shaped, a number of other shapes could also be used, for example, circles, rectangles, or triangles. However, it is advantageous if the drive elements 12, 13 on the mounting surface 7 each have a driving face 27, 28 that is substantially perpendicular to the mounting plane and the drive elements 14, 15 on the contact surface 31 each have a drivable face 29, 30 that is substantially perpendicular to the mounting plane.

When the driving faces 27, 28 on the projections 12, 13 are pushed into contact with the drivable faces 29, 30 on the recesses 14, 15 by the rotation of the drive element 3, the rotational force transferred by the quick-release coupling 1 to the abrasive disc 2 is greater. This is N:Melburne\Cases\Ptent\74D0074999\P74805.AU\Spcvi\P74805.AU Gil Sped as Oled.doc 14/11/07 12 O enhanced when the driving faces 27, 28 of the drive elements 12, 13 on the mounting surface 7 are generally O parallel and equally offset from the diameter of the Z quick-release coupling 1 and the drivable faces 29, 30 of the drive elements 14, 15 on the contact surface 31 are generally parallel and equally offset from the diameter of the abrasive disc 2.

SIt will be clear that there can be more or less than two projections 12, 13 on the mounting surface of the quickrelease coupling 1 and more or less than two recesses 14, 15 on the mounting surface of the abrasive disc 2.

Alternatively or additionally, there can be one or more recesses on the mounting surface of the quick-release coupling 1 and one or more corresponding projections on the mounting surface of the abrasive disc 2.

In the preferred embodiment the shapes of the first major face 6 and the second major face 7 of the quick-release coupling 1 are annular. However, the shapes could be any geometrically symmetrical shape, for example, a circle, square, or regular polygon.

While some preferred aspects of the invention have been described by way of example, it should be appreciated that modifications and/or improvements can occur without departing from the scope of the invention as set out in this specification.

The terms comprise, comprises, comprising, or comprised, if and when used herein, should be interpreted nonexclusively, that is, as conveying "consisting of or including".

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the N \lbo.re\Case\Paten t\74000-7499\P748OS AtASpecisP74805 AU GH Sp~i as fileddoc 14/11/07 -13 common general knowledge in the art, in Australia or any other country.

N \Melbou.me\Cues\Patenr\74000.74999\P74805.A1JSpecis\P74805.AU GH SPC-Ci A3 fiWedac 14/11/07

Claims

2. A coupling according to claim i, wherein the mounting surface has two drive elements that are generally diametrically opposite on the surface and equally spaced from the central axis.
3. A coupling according to claim 2, wherein the driving faces of the drive elements on the mounting surface are generally parallel and equally offset from the diameter of N:\Melboume\Cases\Patent\740DO-74999\P74805.AL\Spccis\P748OSAU GH Speci as filddoc 14/11/07 15 O the coupling and the drivable faces of the drive elements on the contact surface are generally parallel and equally O offset from the diameter of the disc.
4. A coupling according to any one of the preceding claims, wherein the or each pair of drive elements consists of a shaped protrusion and a correspondingly shaped recess. A coupling according to claim 4, wherein the or each pair of drive elements consists of a fin-shaped protrusion Sand a correspondingly fin-shaped recess.
6. A coupling according to any one of the preceding claims, wherein the second major face is substantially parallel to the first major face.
7. A coupling according to any one of the preceding claims, wherein the coupling includes an aperture that passes between the centre of the first major face and the centre of the second major face.
8. A coupling according to claim 7, wherein the aperture is cylindrical.
9. A coupling according to any one of the preceding claims, wherein the coupling includes a centrally located extension from the second major face. A coupling according to claim 9, wherein the extension is cylindrical.
11. A coupling according to claim 9 or 10, wherein the extension is a collar around the aperture.
12. A coupling according to any one of the preceding claims, wherein the shape of the first major face and the second major face is annular, circular, square, or a N \Melbourne\Cases\Patenr\74000-74999\P748O5AtPSpecis\P74SSAU GH Speci as fileddoc 14/11/07 16 Q)regular polygon. O 13. A coupling according to claim 12, wherein the shape of the first major face and the second major face is annular.
14. A coupling according to any one of the previous claims, wherein the coupling is formed integrally with the drive means of the grinding apparatus. (Ni
15. An abrasive disc mountable on the drive coupling of a O grinding apparatus and adapted for rotation about a central (Ni axis, the disc comprising a rear face and an operative front face, the rear face presenting a contact surface to cooperate with a mounting surface of the coupling, the disc being adapted to engage the coupling along a mounting plane at the interface between the contact surface and the mounting surface, the contact surface having one or more drive elements that are each sized to cooperate with a corresponding drive element on the mounting surface and to position the disc on the coupling, the first drive element in each cooperating pair being a protrusion from one of the surfaces and the second drive element in each cooperating pair being a recess in the other surface, the protrusion capable of being received and retained in the recess, the or each drive element on the mounting surface having a driving face substantially perpendicular to the mounting plane and the or each drive element on the contact surface having a drivable face substantially perpendicular to the mounting plane, whereby when the disc is mounted on the coupling at least a substantial portion of the or each driving face contacts at least a substantial portion of the corresponding drivable face to provide a driving force in the direction of rotation.
16. An abrasive disc according to claim 15, wherein the contact surface has two drive elements that are generally diametrically opposite on the surface and equally spaced N \Melboure\Cases\Patent\74000-74999\P74OS AL\Specis\P74805.AU GH Speci as fileddoc 14/11/07 17 from the central axis. O 17. An abrasive disc according to claim 16, wherein the Z drivable faces of the drive elements on the contact surface are generally parallel and equally offset from the diameter of the disc and the driving faces of the drive elements on the mounting surface are generally parallel and equally offset from the diameter of the coupling. (Ni
18. An abrasive disc according to any one of claims 15-17, Swherein the or each pair of drive elements consists of a (1 shaped protrusion and a correspondingly shaped recess.
19. An abrasive disc according to claim 18, wherein the or each pair of drive elements consists of a fin-shaped protrusion and a correspondingly fin-shaped recess. An abrasive disc according to any one of claims 15-19, wherein the rear face is substantially parallel to the front face.
21. An abrasive disc according to any one of claims 15-20, wherein the disc includes an aperture that passes between the centre of the front face and the centre of the rear face.
22. An abrasive disc according to claim 21, wherein the aperture is cylindrical.
23. An abrasive disc according to any one of claims 15-22, wherein the shape of the front face and the rear face is annular, circular, square, or a regular polygon.
24. An abrasive disc according to claim 23, wherein the shape of the front face and the rear face is annular. A method of mounting an abrasive disc according to any N.\Meiboune\Cases\Patent\74000-74999\P74805 AU\Specis\P74805AU GH Speci as filcd.doc 14/1107 18 Sone of claims 15-24 to a grinding apparatus using a coupling according to any one of claims 1-14, wherein the z provision of cooperating drive elements facilitates mounting of the disc in a desired position on the coupling.
26. The method according to claim 25, wherein more than one pair of cooperating drive elements are spread equally apart to allow mounting in more than one selected position. (cN 10 27. The method according to claim 25 or 26, wherein an Saxially mounted locking nut is used to secure the disc in c position on the coupling.
28. The method according to any one of claims 25-27, wherein a number of radially dispersed mounting bolts are used to secure the disc in position on the coupling.
29. A grinding apparatus including a coupling according to any one of claims 1-14. A grinding apparatus according to claim 28, wherein an abrasive disc according to any one of claims 15-24 is attached to the coupling.
31. A coupling substantially as herein described or exemplified, with reference to the accompanying drawings.
32. An abrasive disc substantially as herein described or exemplified, with reference to the accompanying drawings.
33. A coupling and disc arrangement substantially as herein described or exemplified, with reference to the accompanying drawings. N:\Mclboume\Cases\Patent\74000-74999\P7480.AY\Spcis\P74805.AU GH Spcci as fllod.doc 14/11/07