AU2007100255A4 - 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 - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION Innovation Patent Applicant: 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 us: 2 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 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.

As used throughout the specification, the term "grinding apparatus" is intended to refer to any device in which, 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 consequently difficult to remove.

N\Mclborn\Caws\Patent\71000-71999\P71 776ALPSpccs\P7I 7?6AU Specification 2007-3-28 doc 28/03/07 3 ;Quick-release couplings to attach an abrasive disc to a Sgrinding apparatus are known in the art, for example, United States Patent No. 6,530,828 describes an abrasive C s disc that has an undercut, spirally shaped edge contour for engagement with a suitable counter-contour on an Saccommodating carrier.

In However, there are a number of difficulties and/or disadvantages associated with the couplings of the prior art, including that the coupling does not allow the (I 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, the coupling comprising a first major face which will engage a drive means and a second major face which comprises a mounting surface for an abrasive disc, the mounting surface comprising one or more mounting means selected from the group consisting of: a protrusion sized and shaped to engage a corresponding recess in an abrasive disc; and a recess sized and shaped to engage a corresponding protrusion from an N \Mclboumc\Cases\Pateni\7 000-71999\P7 j776AU\Specis\P71776 AU Specification 2007.3-2g8doc 28/03107 4 abrasive disc.

Expediently the second major face is substantially parallel to the first major face.

In one embodiment, the coupling includes an aperture that passes between the centre of the first major face and the centre of the second major face. Preferably the aperture is cylindrical.

In another embodiment, the coupling includes a centrally located protrusion from the second major face of the coupling. Preferably the protrusion is cylindrical. In a further embodiment, the protrusion is a collar around the aperture that passes between the centre of the first major face and the centre of the second major face.

Expediently, the mounting means or each mounting means extends from the centre of the second major face of the coupling. Preferably where there are two or more mounting means, each mounting means is on the opposite side of the centre of the second major face from another mounting means.

Preferably the mounting means includes a straight edge that extends from the centre of the second major face.

Preferably the corresponding recess in or protrusion from the abrasive disc includes a straight edge that extends from the centre of the abrasive disc.

In one embodiment, the shape of the mounting means or each mounting means is fin-shaped. Preferably the shape of the corresponding recess in or protrusion from the abrasive disc is also fin-shaped.

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

N \Melbou ne\Cases\Patent\71000.71999\P71776 AU\Specis\P7]776AU Specificaion 2007-3-28doc 28/03/07 5 Q)The engagement of the mounting means with the c-I ;corresponding recess in or protrusion from the abrasive Sdisc preventing rotation of the abrasive disc relative to the coupling. In some circumstances, it may be necessary C 5 to supplement the axially mounted locking nut with a number of radially dispersed mounting bolts.

In C Preferably the shape of the first major face and the second major face of the coupling is annular, circular, square, or a regular polygon. Expediently the shape of Sthe first major face and the second major face of the C coupling is annular.

According to a second aspect of the invention, there is provided an abrasive disc comprising an operative face and a rear face, the rear face of which comprises a contact surface for a coupling with a mounting surface, the contact surface comprising one or more contacting means selected from the group consisting of: a protrusion sized and shaped to engage a corresponding recess in the mounting surface of the coupling; and a recess sized and shaped to engage a corresponding protrusion in the mounting surface of the coupling.

In one embodiment, the contact surface comprises at least one pair of contacting means, with each contacting means in the pair or in each pair extending from the opposite side of the centre of the disc from the other contacting means in the pair or in each pair.

In another embodiment, the contacting means or each of the contacting means is fin-shaped with a substantially straight edge extending from the centre of the disc.

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 N \elboume\Cams\Paen\7 1000-71999\P71 776.ALASpecis\P7]776 AU Spccificalton 2007-3-28doc 2810307 6 only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of the quick-release coupling.

Figure 2 is a plan view of the quick-release coupling.

Figure 3 is a side view of the quick-release coupling.

Figure 4 is a plan view of the rear face of the abrasive disc.

Figure 5 is a plan view of the operative face of the abrasive disc Figure 6 is an exploded side view of the quick-release 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 detached from a drive means 3 in a grinding apparatus.

As used throughout the specification, the term "drive 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.

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 for the abrasive disc 2.

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

The quick-release coupling 1 includes a cylindrical N \Mlbourne\Cases\Paen\7 000-71999\P71 776ALASpccis\P7 776 AU Specificaion 2007-3-28doc 28103/07 7 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 1. The aperture 9 is designed to engage with a cylindrical projection 8 from the flexible coupling 5 to assist in mounting the quickrelease coupling 1 to the flexible coupling The quick-release coupling 1 also includes a centrally located cylindrical collar 10 around the circumference of io 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 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 1.

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 1, the cooperating fin-shaped projections 12, 13 and recesses 14, described below restraining the abrasive disc 2 from rotation relative to the quick-release coupling 1. In N \Melboume\Case\Patent\7 1000-71999\P7 1776AU\Specis\P71 776AU Specificauion 2007-3-28doc 28/03/07 8 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.

The mounting surface on the second major face 7 of the quick-release coupling 1 comprises two fin-shaped projections 12, 13 that each extend from opposite sides of the collar 10. The two fin-shaped projections 12, 13 are sized and shaped to engage with two corresponding finshaped recesses 14, 15 that each extend from opposite sides of the aperture 11 in the contact surface of the abrasive disc 2.

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 corresponding fin-shaped recesses 14, 15. This is much easier for the operator to do in the often hot and dusty 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 N Alelbourn\Cases\PatcnRk7lOOO-71999\P7I776AU\Specis\P71776 AU Spccificaion 2007.3-28doc 28/03/07 9 other parts of the same disc.

An advantage of positioning the fin-shaped projections 12, 13 on opposite sides of the collar 10 on the quick-release coupling 1 and the fin-shaped recesses 14, 15 on 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 i, 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 shape used has a straight edge 27, 28, 29, 30 that extends from the centre of the quick-release coupling 1 or abrasive disc 2. When the straight edges 27, 28 on the projections 12, 13 are pushed into contact with the straight edges 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.

It 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, on the mounting surface of the abrasive disc 2.

Alternatively or additionally, there can be one or more recesses 14, 15 on the mounting surface of the quickrelease coupling 1 and one or more corresponding projections 12, 13 on the mounting surface of the abrasive disc 2.

N.\Mclbourne\Cass\Patent\71 000-71 999\P71 776AU\Spcis\P7] 776AU Specification 2007-3-2gdoc 28/03/07 10 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".

N \Melbourne\Cascs\Paini\7 I000.71999\P71776 AU\Spccis\P7 776AU Specificaion 2007-3-28.doc 28/03/07

Claims (4)

1. An abrasive disc comprising an operative face and a rear face, the rear face of which comprises a contact s surface for a coupling with a mounting surface, the contact surface comprising one or more contacting means selected from the group consisting of: a protrusion sized and shaped to engage a corresponding recess in the mounting surface of the coupling; and a recess sized and shaped to engage a corresponding protrusion in the mounting surface of the coupling.

2. An abrasive disc according to claim 1, wherein the contact surface comprises at least one pair of contacting means, with each contacting means in the pair or in each pair extending from the opposite side of the centre of the disc from the other contacting means in the pair or in each pair.

3. An abrasive disc according to claim 1 or 2, wherein the contacting means or each of the contacting means is fin-shaped with a substantially straight edge extending from the centre of the disc.

4. An abrasive disc substantially as herein described or exemplified, with reference to the accompanying drawings. A coupling and disc arrangement substantially as herein described or exemplified, with reference to the accompanying drawings. N \Mclboure\Cases\Patent\71000-7199\'P71776AU\SpccisTP7776 AU Specificaton 2007-3-28doc 28/03/07