BACKGROUND OF THE INVENTION

THIS invention relates to an accessory for a fastener. More specifically, the invention relates to an accessar for a fastener in the form of a frangible, quick release washer interposafole between a bolt-iike fastener (i.e. bolts, studs, shanks, shafts) and a nut for in use, enabling the controlled release of tension acting between the bolt-like fastener d t e nut for the purposes of quickly loosening the nut.

It is envisaged that one or many applications of th invention is for use in conjunction with rotary power tools, such an angle grinder, typically comprising a shank on which a cutting disc is seeurable by a nut.

In use, th nut becomes overly tightened by the rotary action of the power tool, making the loosening of the nut very difficult, Typically, the nut comprises a formation by whic it may be engaged b a wrench for the purposes of loosening and/or tightening,

However, ove time these formations wear allowing slip between the wrench and the nut making loosening of the nut very difficult. Where the nut simply cannot be loosened wit the wrench, users tend to turn to methods that tend to damage the nut and/or power tool, i.e. a chisel and hammer.

In an attempt to address the damaging and time-consuming problems of the above described wrench loosening method, many types of quick release nuts have been developed. One such quick release nut is described in US patent application no. 2009/169336. Although quick release nuts appear to solve aforementioned problems, they tend to be overly engineered devices that are very expensive. ft is therefore an object of the present invention to provide a cheap, disposable quick release washer type accessory for a fastener that addresses the disadvantages of the prior art methods and device set out above. ^■ SUMMARY OF THE INVENTION

According to the invention there is provided an accessory for a fastener including: a pair of load-bearing members; a spacer member interposed between the load-hearing members, the spacer member having one or more frangible zones defined thereon; and an extraction member connected to the spacer member for, on application of a force on the extraction member, fragmenting the spacer member at the frangible zones and extracting the fragmented spacer member from between the load-bearing members, thereby enabling displacement of t e Soad-bearing members toward one another:

Typically, the load-bearing members are annular washers defining central apertures through which a bolt-like fastener is receivable, the load-bearing washers each comprising ©perative!y outer load-beanng surfaces for in use and in the alternate, bearing against an object or a fastening nut Ihreadabiy engageabie with the boit-iike fastener thereby to secure the accessory thereon in a sandwiched configuration between the object and the fastening hut.

Generally, one or more of the load-bearing members comprise locating formations for locating the respective load-bearing member relative to the other load-bearing member and/or to the space member. Preferably, .the locating formation extends axial fy from an operatively inner surface of the load-bearing member.

Furthermore, one of the load-bearing members may comprise a. guide stem extending axiaify there from, the guide stem being engageabie with th aperture .of the other load- bearing member to in use, and on extraction of the spacer member, guide the axial displacement of the load-bearing members relative to one another.

In one particularly preferred embodiment, the accessory ma include a means for releasably securing the load-bearing members to one another, and/or individually or joirsi!y to th spacer member, the releasable securing means being configured to release the load-bearing members and/or the spacer member from one another on extraction of the spacer member from the load-bearing members.

Typically, the reieasabSe securing means is one or more adhesive zones for temporarily securing the load-bearing members and/or the spacer rnerrsber to on© another,

Preferably, the spacer member is an annular spacer member having an inner edge with a diameter smaller than the diameter of outer edges of the load-bearing members, the inner edge of the annular spacer member being correspondingly iocatab!e with the locating formations on the one or more load-bearing members.

Generally, the annuiar spacer member comprises an outer edge having a diameter reater than the diameter of the outer edges of the load-bearing members such that the outer edge of the annular spacer member extends beyond the outer edges of the load- bearing members.

The outer edge of the annular space member may be a¾a raised thereby to engag the outer edges of the load-bearing members to provide a secondary means of locating the load-bearin members and the annuiar spacer member relative to one another. in anothe preferred embodiment of the invention, the annular spacer member may comprise one or more flexure zones for enabling portions of the annular spacer member to. bend relative to one another, for In use aiding extraction of the annular spacer member from between the load-bearing members. Generally, the flexure zones are a .plurality of cut-outs defined in the annular spacer member, the cut-out being cut radially outwardly from the inner edge of the annular spacer member or radially inwardly from the outer edge thereof.

Typically, the extraction member is an extracting pull ring having an inner edge with a diameter greater than the outer edge of the annular spacer member, the extracting pull ring being connected to the annular spacer member at a connection zone and angularly displaceable about the connection zone. Preferably, the extracting pull ring is angularly disp!aceabie about the connection zone between a first position and a second position. In the firs position, the extracting pull ring and trie annular spacer member may lie substantially concentrically and coptanar wth one another.

In the second position, the extracting pull ring may be capable of being puffed up and over the connection zone thereby in us enabling a radially outwardly puis force to be applied to the annuiar spacer member to caus fragmentation of the annular spacer member at the frangible zones and the extraction thereof from between the ioad- bearing members.

Generally, the connection zone on the annular spacer member is located near a recessed zone of reduced axial thickness so as to enable the connection zone to wist consequently enabling angular displacement of the extracting puii ring thereabout.

^' Typically, the extracting puii ring is releasabfy retained i the first position relative to the annular spacer member by one or more frangible posts extending radially between the outer edge of the annuiar spacer member and the inner edge of the extracting pull ring, the frangible posts being frangible in us on angular displacement of th extracting pull ring from the first position to the second position.

Preferably, the extracting pull ring comprises a lifting tab, located diametrically opposite the connection zone, for providing finger access to a user to in use raise the extracting pull ring from the first position, ore preferably, the extracting pull hng and the annuiar spacer member are integral with one another.

According to a second aspect of the Invention, the accessory is securab!e to a cutting disc According to a third aspect of the Invention, there is provided a cutting disc with an accessory for a fastener secured thereto, the accessor for a fastener including: a pair of load-bearing members; a spacer member interposed between the ioad-beahng members, the spacer member having one or more frangible zones defined thereon; and an extraction member connected to the spacer member for, on application of a force on the extraction member, fragmenting the spacer member at the frangible zones and extracting the fragmented spacer member from between the ioad-bearing members, thereby enabling displacement of the load-bearing members toward one another.

BRIEF DESC IPTiaM Of THE RA WINGS-

The inventio will new foe described in more detail, by way of example only, with reference to the accompanying drawings in which;

Figure 1 is a perspective exploded view Pi an accessory for a fastener relative

to a rotary power tool onto which the accessory is In use seeurable;

Figure 2 Is a perspective view of the accessor of figure- secured onto the rotary power tool;

Figure 3 is a perspective exploded view of the accessor in accordance with the present invention;

Figures 4A-4E are a series of perspective views illustrating siep-by-sfep how ^' the accessory is employed In use; and

Figure 5 is a perspective view of an accessory for a fastener in accordance with the invention, with the accessory secured to and/or Integra! with a Gutting disc. DETAILED DESCRIPTION OF THE DRAWI GS

An. accessory for a fastener according to a preferred embodiment of the invention is designated generally in the accompanying figures with reference numeral 10. With reference now to figure 4, the accessory for a fastener 10 includes a pair of load- bearing members 12, 14, a spacer member 16 and an extraction member 18.

Refernng now to figur 1 and figure 2, it is envisaged that one of many possible applications of the accessory 10 is acting as a disposable, quick release washer for a rotary fool, suc as an angle grinder 2QQ, Typically, a cutting disc 21.0 is secured to a shank 22 of the angle grinder 2GG by a n u 230, ge ne rally tightened onto the shank with a wrench (not shown).

In use, and as a result of the rotar torque experienced by the nut 230 during operation, the nut 230 becomes overly tightened, making the loosening of the nu 230 very difficult and time consuming. By interposing the accessory 10 between the cutting disc 210 and the nut 21G, this shortcoming ca be addressed as will be described in this specification. Although the invention will be described in this specification with reference to the shank 220 of an angle grinder, it will fee appreciated thai the accessory 10 niay _. be used in any application on any similar bolt-like fastener including bolts, shafts, threaded bar, etc.

The load-bearing members, typically in the form of ioad-beanng annular washers 12, 14, each define a centra! aperture 20, 22 through which the shank 22G is receivable to In use enable the accessory 10 to be mounted on the shank 220. Each of the annular load-bearing washers 12, 14 comprise of operative^ outer load-bearing surfaces 24, 26 for in use bearing against the nut 230 and the cutting disc 210 respectively, The load-bearing annular washers 12, 14 include formations 28. 3Q projecting axially from operafively inner surfaces 28, 30 thereof. The formation 28 projecting axially from the operativefy inner surface 28 of the load-bearing annular washer 12 is a locating formation 28 for locating one or both of the load-bearing annular washers 12, 14 with an inner edge 16A of the spacer member 16. The formation 30 projecting axialiy from the operallvely inner surface 30 of the load- bearing annular washer 14 is a guide stem 30, the guide stem being engageabie with the aperture 20 of the load-bearing annular washer 12 to in use, and on extraction of the spacer member 16 from between tne load-hearing annular washers 12, 14, guide axial displacement of the load-bearing annular washers 12, 14 relative to one another.

Although the individual components 1.2, 1,4, 18 may be separate, loose components, it is preferable and more convenient that a releasabie securing means temporarily hoists the components 12, _. 14, 16 to form a temporary one piece accessory 10. Typically, the reSeasable securing means is an adhesive applied at one or more adhesive zones for temporarily bonding the load-bearing annular washers 12, 14 to each other, snd sr individually or jointly to the spacer member 16,

Th spacer member 18 is preferably In the form of an annular spacer member 16, wiifr the inner edge 18A thereof having a diameter smaller than the diameter of outer edges 12A... 14A of the load-bearing annular washers 12, 14, the inner edge ISA of the annular spacer member 1© being correspondingly loca!able with the locating formation 28 on the load-bearing annular washer 12. The annular spacer member 16 comprises an outer edg 168 having a diameter greater than the diameter of the outer edges 12A, 14A of the load-bearing annular washers 12, 14 such that the outer edge 16B of the annular spacer member 16 extends beyond the outer edges 12A, 14Ά of the load-bearing annular washers 12, 14. The outer edge 16B of the annular spacer member 16 is axialiy raised thereby to engage the outer edges 12A, 14A of th load-bearing annular washers 12, 14 to provide a secondary means of locating the load-bearing annular washers 12, 1 and the annular spacer member 16 relative to one another. The annular spacer member 18 comprises a frangible zone, in the form of a frangible lin 32 along with the annular spacer member 16 is capable of fragmenting on application of a sufficient force applied thereon. Th annular spacer member 16 further comprises one or more flexure zones, In the form of radial cut-outs 34 cut radially outwardly into the annular spacer member 16, for enabling portions of the annular spacer member 16 to bend relative to one another for in use aiding extraction of the annular spacer membe 18 from between the load- bearing annular washers 12, 14.

The extraction member 18 is typically In the form of an extracting pull ring 18 having an inner edge 18A wit a diameter greater than the outer edge 18B of the annular spacer member 16. The extracting pull ring 18 is connected te the annular spacer member 16 at a connection zone 36, about which th extracting pull ring 18 is angularly displaceabie.

The extracting pu\\ ring 18 is angularly displaceable about the connection zone 36 between a first position (as illustrated in figure 4A) and a second position (as substantially illustrated In figure 40). In the first position, the extracting pull ring 1 S and the annular spacer member 16 lie substantially concentrically and coplartar with one another..

In the second position, the extracting pull ring 18 pulled up and over the connection zone 36 thereby In use enabling a radially outwardly pull force "F" to be applied to the annular spacer member 16 to cause fragmentation of ^' the annular spacer member 16 at the frangible zone 32 (as illustrated in figure 4D).

The connection zone 36 is located near a recessed zone 38 on the annular spacer member 18, the recessed zone 38 being a zone of reduced axial thickness so as to enable the connection zon ^' 36 to twist, consequently enabling angular displacement of the extracting pull ring 18 there about.

The extracting pull ring 18 is releasably retained in the first position relative to the annular spacer member 16 by one or more frangible posts 40 extending radially between the outer edge 168 of the annular spacer member 16 and the inner edge ISA of the extracting pull ring 18, the frangible posts 40 being frangible in use on angular displacement of the extracting pull ring from the first _. osition to the second position. The extracting pull ring 16 further comprises a lifting tab 42, iocated diametrically opposite the connexion zone 36, for providing finger access to a user to In use raise the extracting puil ring 18 from the first position. Preferably, the extracting pull ring 18 and the annular spacer member 16 are integral with one another.

Figures 4A to 4E illustrate how the accessory 1.0 is used to quickly release the nut 230 from the shank 220 of the angle grinder 200. In use, the accessory 10 is in the first position with th extracting pull ring 18 and th annular space membe 16 lying substantially concentrically and copfanar wit one another as illustrated in figure 4.A.

To remove the cutting disc 210 from the angle grinder 200, a user with his finger(s) grips the lifting tab 42 to raise and angularl displace the etfttactirig pull ring 18 relative to the annular spacer member 16, thereby causing the extracting pull ring 18 to break from the annular spacer member 16 at the frangible posts 40 as illustrated in figure 4 .

With reference ho to figure 4C, as the extracting pull ring 18 continues to angularly displace about the connection zone 36, the extracting pull ring 18 and mor specifically the pull tab 42, move upwardly and over the nut 230 substantiall into the second position.

With a radially outwardly pull force "F ^" exerted by ^' the user on the extracting pull ring 18, the annular spacer member 16 fragments along the frangible line 32 as is illustrated in figure 4D. As the extracting pull ring 18 is continually pulled by the user, the extracting pull ring 18 and th fragmented annular spacer member 16 is removed from between the load-bearing washers 12, 14 such that the load-bearing washers 12, 14 become axiaily dispiaceabte relative to one another. it will be appreciated that the axial displacement of the load-bearing; washers 12, 14 towards one another releases the tension between the shank 220 and the nut 230, consequently enabling the nut 230 to be quickly and easily loosened from the shank 220.

Although the invention has been described above with reference to preferred embodiments, It will be appreciated that man modifications or variations of the inventlon are possible without departing from the spirit or scope of the invention. For example, and with reference to figure 5, the accessory 10 may be secured and/or integral with the cutting disc 210 instead of being a separate component as heresn described.