AU2013206569A1 - Improvements to ground engaging tool attachment means - Google Patents

Abstract

A mechanical locking means of a wear member 12 attachment means, the attachment means arranged to releasably attach the wear member to a bucket of earth moving equipment. The attachment means has a rotary fastener 20 operated to releasably attach the wear member to the bucket, the rotary fastener 20 is rotatable to attach the wear member to the bucket and counter-rotatable to enable release of the wear member from the bucket. The locking means includes at least one locking member (e.g. resilient members 32) to engage with the rotary fastener (e.g. ratchet wheel 44) to prevent the counter-rotation of the rotary fastener until the locking member is released. C) mD00 0") CCt) C C:) CD% CV)CC

Description

1 IMPROVEMENTS TO GROUND ENGAGING TOOL ATTACHMENT MEANS FIELD OF THE INVENTION [0001] The present invention relates to improvements to ground engaging tool (GET) wear member attachment means. [0002] In particular, the present invention relates to maintaining attachment of such wear members to surfaces subject to abrasive wear, such as earth moving buckets. BACKGROUND TO THE INVENTION [0003] Buckets for earth moving equipment, such as excavators, are subject to a high degree of abrasive wear. This wear is particularly pronounced at a leading edge of the bucket, where ground engaging tools such as adaptors and teeth are used to penetrate matter being dug. It is also found at bucket corners and heels, although wear in these areas is not as pronounced as at the leading edge. [0004] In order to prolong the working life of a bucket, and to retain structural strength in the face of this wear, it is common practice to fix replaceable wear members to those parts of the bucket most subject to wear. Traditionally wear members such as teeth, wear strips and heel shrouds have been welded into place on a bucket. [0005] Although the welding of wear members to buckets provides a secure means of attachment, it has significant practical difficulties. Replacement of worn members requires the cutting out of the worn member, and the fitting and re welding of a new member in its place. Such metal-working operations require specialised equipment and trained boilermakers.

2 [0006] Where the bucket is being employed remotely, the removal of the bucket, transportation to a suitable workshop, replacement of the worn member and transportation back to the remote location can result in a significant time delay, and thus a loss of production. As excavators are often highly expensive, the underutilisation caused by the need for bucket repairs has a significant economic consequence. [0007] In response to this problem, methods of mechanically attaching ground engaging tools to the leading edge of the bucket have been developed. An example of such a method is disclosed in the international patent application published as number WO 02/12642, in the name of a predecessor of the present applicant. Particular solutions to this problem are disclosed in international patent application number PCT/AU2012/000564, the applicant of which is a related company of the present applicant. The contents of PCT/AU2012/000564 are herein incorporated in their entirety by reference. [0008] Generally, known methods of mechanically attaching ground engaging tools to a bucket leading edge involve providing the ground engaging tool with a channel which locates about the bucket leading edge, and then clamping or bolting the ground engaging tool in a particular position along the bucket edge. [0009] The geometry of this arrangement greatly assists in the attachment of ground engaging tools. The principle forces to which the tools are subjected are shear forces and compressive forces, and generally speaking these forces are transmitted directly to the bucket leading edge, rather than through the clamp or bolt being used. The mechanical attachment is thus only really required to prevent lateral movement of the tool along the bucket edge, or the pulling away of the tool from the bucket edge. [0010] However, a problem has been realised in ground engaging tool attachment systems that utilise a rotary or helical thread fastener as part of the mechanism to retain the wear member to the bucket. When the ground engaging 3 equipment is in use, shear forces, compressive forces and vibration through the wear member from the vehicle or use can cause the fastener (often being one of more bolts) to loosen. This can result in the wear member coming loose and no longer properly transferring forces through to the bucket, whereby the wear member or bucket may become damaged or wear prematurely. Also, the fastener can become damaged, particularly a head of the fastener, which may mean that the fastener cannot be properly operated when the wear member or its attachment means need replacing. [0011] The present invention seeks to provide a mechanical means of ensuring that a wear member attachment means does not loosen. SUMMARY OF THE INVENTION [0012] With the aforementioned in mind, the present invention provides a mechanical locking mechanism of a wear member attachment means, the attachment means arranged to releasably attach the wear member to a bucket of earth moving equipment, the attachment means including a rotary fastener arranged and configured to be operated to releasably attach the wear member to the bucket, the rotary fastener rotatable to enable attachment of the wear member to the bucket and counter-rotatable to enable release of the wear member from the bucket, the locking means including at least one locking member to engage with the rotary fastener and prevent the counter-rotation of the rotary fastener until the locking member is released. [0013] Thus, the locking means prevents loosening of the rotary fastener and thereby helps to maintain attachment of the wear member to the bucket and reduces risk of premature damage to the wear member or its attachment means, or the bucket, or need of early wear member replacement. Preventing unwanted loosening of the rotary fastener also reduces risk of damage to the rotary fastener itself.

4 [0014] The locking means may include a ratchet mechanism, whereby a ratchet allows rotation of the rotary fastener to tighten the attachment means, but prevents or restricts counter-rotation of the rotary fastener to prevent loosening or removal of the wear member. [0015] The ratchet mechanism may include a knurled or toothed portion around a portion of the rotary fastener, and arranged to engage with one or more resilient members. This may be provided as a ratchet gear, sleeve or wheel. [0016] Alternatively, the one or more resilient members may be provided on the rotary fastener and the knurled or toothed portion on another part of the attachment means or on the wear member. [0017] The one or more resilient members may include one or more pawls. The one or more resilient members engaging with the knurled or toothed portion to provide a one way ratchet mechanism. [0018] The one or more resilient members may be integrally formed with a part of the locking means or may be separately formed and subsequently attached. [0019] The one or more resilient members may be formed of plastic, such as a polyurethane material, acetal or nylon. [0020] Alternatively, the resilient member(s) may be formed of metal, such as one or more biased member(s) e.g. spring loaded pawls. [0021] The one or more resilient members may be provided as an insert for insertion into a component of the locking means or attachment means, such as a spacer. [0022] The spacer may include an aperture to receive a resilient member insert.

5 [0023] The locking means may be arranged such that destruction or disablement is required in order to release the lock and allow release of the rotary fastener and thereby of the attachment means. The locking means may be sacrificial in that, in order to release the locking means, the locking means is damaged and must be replaced. Therefore, destruction or disablement of the locking means may include forcing the one or more resilient members beyond a point at which a counter-rotation force can be resisted, such as by applying a pneumatically or electrically powered rotary driver to the rotary fastener. Thus, replacement or refitting of the wear member may include replacement of the locking means or part thereof, such as a component bearing the resilient member(s), which may be a consumable item. [0024] The at least one resilient member may be incorporated into a spacer of the attachment means. The spacer may include an aperture arranged to receive therethrough a portion of the rotary fastener. The spacer may be provided to act between fixed and movable portions of the attachment means, such as shown and described in international patent application PCT/AU2012/000564. [0025] The at least one resilient member may be provided on an insert that is inserted into an opening in a front face of the wear member. For example, wear member may be mounted to the bucket, and retained in place by the attachment means by rotation of the rotary fastener. The insert may then be inserted into an opening in the front face of the wear member so that the at least one resilient member engages with a ratchet wheel around the rotary fastener to prevent counter-rotation of the rotary fastener and thereby prevent loosening of the attachment means, and thus prevent loosening of the wear member. [0026] The at least one resilient member may form part of the insert or the insert may be provided as a retainer to hold the resilient member(s) in place. for example, the insert may act as a retainer.

6 [0027] The ratchet gear or wheel may be formed as part of the rotary fastener or added as a discrete item, such as by press fit onto a shaft of the rotary fastener. [0028] At least one embodiment of the rotary fastener may include the ratchet wheel mounted adjacent or at a distal end thereof, the distal end arranged to contact a face of the attachment means, such as a boss formed on the wear member. [0029] The ratchet wheel may be provided as a proximal end of the rotary fastener adjacent or at a drive portion that arranged to receive a drive member of a tool to rotate the rotary fastener. The drive portion may include a hexagonal internal or external drive head. [0030] Alternatively, the ratchet wheel may be integrally formed on the rotary fastener, such as by machining or casting. For example, channels or grooves may be formed along a portion of a shaft of the rotary fastener, the grooves or channels form crests therebetween i.e. effectively a toothed gear. [0031] The wear member attachment means may include a plurality of said rotary fasteners and a said locking means associated with each said rotary fastener. Thus, where the wear member is attached by multiple fasteners, such as a twin bolt and moveable engaging means system, multiple locking means may be employed. BRIEF DESCRIPTION OF THE DRAWINGS [0032] Figures 1 to 4 show a wear member and wear member attachment means with a locking mechanism according to a first embodiment of the present invention.

7 [0033] Figures 5-9 show a wear member and wear member attachment means with a locking mechanism according to a second embodiment of the present invention. [0034] Figures 10 to 13 show a wear member and wear member attachment means with a locking mechanism according to a third embodiment of the present invention. [0035] Figures 14 to 17 show a wear member and wear member attachment means with a locking mechanism according to fourth embodiment of the present invention. DESCRIPTION OF PREFERRED EMBODIMENT [0036] Various embodiments of the present invention will hereinafter be described with reference to the drawings. The drawings depict four alternative embodiments of the present invention. It will, however, be appreciated that the inventive concept is not to be taken as being limited to only those embodiments. The scope of the present invention is defined by the description and claims. [0037] Embodiments of the present invention incorporate a ratchet arrangement to unwanted release of the fastening system used to retain the wear member to the bucket. Thus, the ratchet arrangement provides a locking system or mechanism of the wear member attachment means. [0038] An aim of this ratchet arrangement is to prevent premature release or loosening of a bolt type attachment means for wear members, such as heel shrouds. [0039] The following embodiments utilise a pawl mechanism and a spacer or insert allowing the bolt to rotate for tightening but preventing the bolt couter rotating and loosening.

8 [0040] Embodiment 1 - see figures 1 to 4: e A ratchet gear is attached to the bolt: o Note, the ratchet gear may be formed as part of the bolt (ratchet gear feature and bolt thread formed on the same bolt) or as a separately attached ratchet gear. o In figure 1 the ratchet wheel is formed of a ring of acetal and applied to the shaft of the bolt. e A spacer with one or multiple pawls, preferably formed by two materials where the pawl(s) is/are metal and embedded into or mounted to a plastic spacer. Alternatively, the spacer may be of metal. e Preferably the spacer and pawl(s) are formed in plastic. [0041] Embodiment 2 - see figures 5 to 9 e A ratchet gear is attached to end of bolt o The ratchet gear feature may be formed as part of the bolt (gear and bolt threads are formed on the same part) e A spacer with one or multiple pawls, preferably formed by two materials where the pawl(s) is/are metal and embedded into or mounted to a plastic spacer. Alternatively, the spacer may be metal. e Preferably the spacer and pawl(s) are formed in plastic. [0042] Embodiment 3 - see figures 10 to 13: e A ratchet gear is provided between the hex drive portion and the thread of bolt. * An additional part - insert with multiple pawls. * Tightening options: o Bolt will be partially tightened and then a pawl insert will be inserted. The bolt will then be finally tightened.

9 o After the bolt is tightened, the insert is inserted into the adapter opening. * The pawl insert will engage with the ratchet/knurling portion of the bolt. [0043] Embodiment 4 - see figures 14 to 17: e A ratchet gear is provided at the end of the hexagonal drive portion of the bolt. e A cap with the pawl(s) is inserted after the bolt is tightened. The pawl(s) engage with the ratchet/knurled gear. [0044] Figure 1 shows an exploded view of a wear member, adaptor plate and attachment means with locking means. Figure 2 shows the components of the locking means, including a spacer 28 with multiple resilient members 32, each formed integral to the spacer and having teeth 46 that engage with the ratchet gear/wheel 44 as the respective resilient member resiliently biases outward. Rotation of the threaded bolt 20 to tighten attachment causes the ratchet gear/wheel to rotate and thereby force the resilient members to ride over the teeth of the ratchet gear/wheel. Counter-rotation of the bolt causes the resilient members to flex outward and positively engage into the grooves/channels. [0045] Figure 3 shows features of the spacer with the resilient members that bias into engagement with the ratchet gear/wheel. Figure 4 shows the wear member attached to the adaptor plate. [0046] Referring to figures 1 to 4, an adaptor plate 10 is mounted onto a lip or edge of a bucket (not shown). A wear member attachment means releasably mounts the wear member 12 to the adaptor plate. The wear member includes a boss 14 with a contact face 15 arranged to engage against a face 16 formed in an aperture 18 of the adaptor plate. The attachment means includes a rotary 10 fastener (bolt) 20 with a threaded portion 20a. The rotary fastener passes through an aperture 22 in the front face 24 of the wear member, through and in threaded engagement with a movable engaging member 26, and through a spacer 28. The rotary fastener in this embodiment is a type of bolt with a hexagonal drive proximal end 30. The spacer has multiple resilient members 32. In use, the spacer sits between the fixed boss on the wear member and the moveable engaging member. Rotation of the rotary fastener (bolt) 20 causes a contact face 34 of the moveable engaging member to engage against a face 42 of the adaptor plate. The distal end 38 of the bolt impinges against the rear face 40 of the fixed boss. Thus tightening rotation of the bolt causes the contact face 15 of the boss 4 and the contact face 34 of the moveable engaging member 26 to apply opposite forces against the respective faces 16 and 42 of the adaptor plate, thereby retaining the wear member in place. The resilient members 32 in the spacer engage with a ratchet gear or wheel 44 on the distal end of the bolt 20. Cooperation between the ratchet gear/wheel and the resilient members allows the resilient members to flex and allow the bolt to rotate, but prevent counter-rotation of the bolt by engaging into grooves or channels of the ratchet gear/wheel. [0047] Figures 5 to 9 show an alternative embodiment. Reference numerals for common components are consistent with figures 1 to 4. However, in this embodiment the locking means includes an insert 46 in an aperture 48 of the spacer. Also, the bolt 20 has a machined or cast ratchet gear/wheel on the distal end 38. Operation is nevertheless the same as in the previous embodiment. The spacer 28 may be formed of different material to that of the insert. For example, in a preferred embodiment the spacer is a metal plate and the insert is of moulded plastic with the resilient members either integrally moulded or separately attached. [0048] However, whilst the spacer can be of metal and the resilient members can be formed of plastic, other combinations of these materials fall within alternative embodiments of the present invention. For example, the spacer can be of plastic and the resilient members of metal, or both the spacer and the 11 resilient members can be of the same type of material (metal or plastic) though of different forms of each, or can both be of exactly the same type of plastic or metal. [0049] Figure 7 shows the insert 46 in close up. The insert has integrally formed resilient members 32. These are arms or fingers 50 with teeth 52 at a distal end of each member. The teeth 52 engage with the teeth of the ratchet gear/wheel 44. [0050] Figure 9 as in figure 4 shows the assembled components without the spacer in place in order to show the position of the ratchet gear/wheel 44 in those embodiments. It will, however, be appreciated that the spacer would be in place between the moveable engaging member 26 and the fixed boss 14 if the locking means was being employed. [0051] If a locking function is not required, the spacer may be omitted, or preferably a spacer used having a plain aperture with no resilient members provided the aperture was sufficiently large to allow passage of the bolt therethrough. [0052] The embodiment shown in figures 10 to 13 show similar components to those of the previous two embodiments. However, the ratchet gear/wheel 44 is provided more towards a proximal end 54 of the rotary fastener 20. In this embodiment, the ratchet gear/wheel 44 is between a hexagonal driving head 30 and the threaded shaft 20a. Attachment of the wear member 12 to the adapter plate 10 is as before; however, the locking means includes an insert 56 arranged to be inserted into the aperture 22 in the front face 24 of the wear member and be retained in a recess 58 in a front edge 60 of the adapter plate 10. The insert has the resilient members 32. The insert 56 includes projections 62a,62b that prevent it rotating in the recess 58 in the front face of the adaptor plate 10 when the bolt 20 is rotated.

12 [0053] Figure 13 shows close up detail of the insert 56 in the recess 58 of the adaptor plate 10. The resilient members 32 are shown in engagement with the ratchet gear/wheel 44. It will be appreciated that the resilient members are, in this embodiment, formed as finger like projections biased at an angle a towards a particular direction. That directional bias allows the resilient members to flex and ride over the crests 64a of the ratchet gear/wheel to allow the ratchet gear/wheel to rotate one way, but to positively engage with the valleys 64b when the bolt is rotated in the opposite direction. The insert may be formed as a one piece injection moulding of plastics material. [0054] Figures 14 to 17 show an alternative embodiment of the present invention. Attachment of the wear member 12 to the adaptor plate 10 is as in previously described embodiments, and reference numerals for like components are carried over. [0055] The locking means includes a ratchet gear/wheel 44 at the distal end 54 of the rotary fastener 20. The ratchet gear/wheel is provided adjacent the hexagonal driving head 30 of the fastener. An alternative form of insert 66 is arranged to be inserted into and retained in an aperture 22 in the front of the wear member. [0056] Figures 15 and 17 shows the insert 66 in detail. The insert has a boss portion 68 with the resilient members 32. The resilient members are biased into engagement with the teeth on the ratchet gear/wheel. The resilient members are angled at an angle P such that they allow one way rotation of the rotary fastener 20. [0057] It will be appreciated that the rotary fastener may be tightened up to positively retain the wear member on the adaptor plate and thereby on the bucket of the earth moving equipment, and then the insert 66 can be inserted, or the insert can first be inserted in the aperture in the front of the wear member and then the rotary fastener tightened.

13 [0058] Advantageously, the aforementioned embodiments of the present invention provide positive locking of the rotary fastener to prevent the attachment means loosening through the rotary fastener counter-rotating because of loads through the assembly when in use. [0059] The attachment means can be further tightened if the wear member starts to loosen because of gradual wear through use, whilst the locking means prevents the attachment means coming undone until required.

Claims (21)

1. A mechanical locking means of a wear member attachment means, the attachment means arranged to releasably attach the wear member to a bucket of earth moving equipment, the attachment means including a rotary fastener arranged and configured to be operated to releasably attach the wear member to the bucket, the rotary fastener rotatable to enable attachment of the wear member to the bucket and counter-rotatable to enable release of the wear member from the bucket, the locking means including at least one locking member to engage with the rotary fastener and prevent the counter-rotation of the rotary fastener until the locking member is released.

2. A locking means as claimed in claim 1, including a ratchet mechanism, whereby a ratchet allows rotation of the rotary fastener to tighten the attachment means, and prevents or restricts counter-rotation of the rotary fastener to prevent or restrict loosening or removal of the wear member.

3. A locking means as claimed in claim 2, wherein the ratchet mechanism includes a knurled or toothed portion around a portion of the rotary fastener and arranged to engage with one or more resilient members.

4. A locking means as claimed in claim 2, wherein one or more resilient members is/are provided on the rotary fastener, and a knurled or toothed portion is provided on another part of the attachment means or on the wear member.

5. A locking means as claimed in claim 3 or 4, the one or more resilient members including one or more pawls.

6. A locking means as claimed in claim 3 or 4, the one or more resilient members integrally formed with a part of the locking means or separately formed and subsequently attached to a part of the locking means. 15

7. A locking means as claimed in any one of claims 3 to 6, the one or more resilient members formed of plastic.

8. A locking means as claimed in claim 7, the plastic including polyurethane, acetal or nylon.

9. A locking means as claimed in any one of claims 3 to 9, the one or more resilient members provided as part of an insert for insertion into a component of the locking means or attachment means.

10. A locking means as claimed in claim 9, the insert being a spacer.

11.A locking means as claimed in claim 10, the spacer including an aperture to receive a resilient member insert.

12.A locking means as claimed in any one of the preceding claims, wherein destruction or disablement releases the locking and allows release of the rotary fastener and thereby release of the attachment means.

13.A locking means as claimed in claim 12, wherein the locking means is designed to fail when a force applying counter-rotation to the rotary fastener exceeds a predetermined threshold.

14.A locking means as claimed in any one of claims 3 to 13, the resilient member(s) provided on an insert to be inserted into an opening in a front face of the wear member, and the one or more resilient members is/are arranged to engage with a ratchet portion on a proximal portion of the rotary fastener adjacent a front face of the wear member.

15.A locking means as claimed in any one of claims 2 to 15, the ratchet mechanism including a ratchet wheel formed as part of the rotary fastener or added as a discrete item. 16

16.A locking means as claimed in claim 15, the ratchet wheel attached to the rotary fastener by press fit or interference fit onto a shaft of the rotary fastener, or integrally formed on the rotary fastener, or attached by a retaining fastener, or adhered to the rotary fastener, or retained by a pin into the rotary fastener.

17.A locking means as claimed in claim 15, the ratchet wheel formed by machining or casting on the rotary fastener.

18.A wear member attachment means including a locking means according to any one of claims 1 to 17.

19.A wear member attachment means as claimed in claim 18, including a plurality of said rotary fasteners and a said locking means associated with each said rotary fastener.

20.A wear member assembly including a wear member attachment means for attaching the wear member to a bucket of earth moving equipment, the wear member assembly including a locking means as claimed in any one of claims 1 to 17 arranged to prevent loosening of the wear member.

21.A wear member assembly as claimed in claim 20, the wear member attachment means including the locking means. SANDVIK INTELLECTUAL PROPERTY AB WATERMARK PATENT AND TRADE MARKS ATTORNEYS P35904AU00