Locking device for a ground engaging tool

Abstract

A locking assembly for releasably attaching a ground engaging tool (GET) to a support member, comprising a body configured to be inserted into a recess formed in the GET, the body comprising: a central body having an end configured to abut with a boss member formed on a surface of the support member, and an internal bore; an actuator screw configured to screwingly engage with the central body so as to be at least partially received within the internal bore of the central body and movable to extend into and out of the internal bore of the central body; and an outer shell configured to extend at least partially over the central body and the actuator screw, the outer shell being mounted with respect to the actuator screw such that movement of the actuator screw in a direction out of the internal bore of the central body causes the outer shell to move with the actuator screw; wherein, to secure the GET to the support member the body is inserted into the recess of the GET such that the end of the central body abuts with the boss member and a reaction plate is inserted within a slot formed in the GET to be positioned behind the body, and wherein the actuator screw is screwingly actuated to extend from the internal bore of the central body to pass through a recess formed in the reaction plate such that the outer shell engages with a surface of the reaction plate to generate a force extending through the body between the boss member and the reaction plate to retain GET in position with respect to the support member.

Description

[0001] LOCKING DEVICE FOR A GROUND ENGAGING TOOL

[0002] FIELD OF INVENTION

[0003] The present invention relates generally to locking device for connecting two components together, and in particular, to a locking device for retaining a ground engaging tool to a piece of equipment for use.

[0004] BACKGROUND OF THE INVENTION

[0005] A ground engaging tool (GET) is a tool that is mounted to an excavation machine, typically to an attachment such as a loader bucket. During use of the machine, the GET protects the attachment from damage to prolong the working life of the attachment. In mining applications, the loader bucket may be used to move dirt and rock from the earth and dump it to a specific location. Thus, during such use, the GET experiences a variety of forces. As a result, a GET is designed to withstand considerable forces during their working life, and is also designed to wear over time, before requiring replacement.

[0006] A common GET is a tool or blade mounted to a lip of a bucket, or attachment thereof, of loader machine. Such tools must be able to withstand considerable forces to contact the ground surface to facilitate removal of rock and the like, and must be mounted to the bucket in a manner that can withstand such forces. Traditionally, such tools were welded to the lip of the bucket and when worn, were cut off and replaced with new tools that were also welded into position. Whilst such a means for attachment provided a degree of strength of attachment, they were time consuming to remove and replace, resulting in machines being off-line for long periods of time when the teeth required replacement, which significantly reduced machine efficiency.

[0007] To address this a variety of different mounting assemblies have been proposed to attach the tools in position for use, with varying degrees of success. Due to the forces acting upon the tools, conventional bolts and fasteners often fail or deform during use, which can require a significant expense to rectify. Other mechanical connection means have been proposed that employ multiple components to facilitate attachment; however, such systems are typically prone to failure due to fine material becoming trapped in the mechanisms as well as rust and corrosion of parts, which cause the connection means to become jammed. This generally requires the use of large hammers and other devices to loosen and / or cut the connection, which has been found to cause damage to the components and significant time delays in replacing the parts, as well as putting the operators at risk of injury.

[0008] Thus, there is a need to provide a connection means for fixing a tool to a device for use, that is capable of withstanding the environmental factors present without causing the components to jam inadvertently and which is simple to use without the need for dedicated tooling.

[0009] The above references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art. In particular, the above prior art discussion does not relate to what is commonly or well known by the person skilled in the art, but assists in the understanding of the inventive step of the present invention of which the identification of pertinent prior art proposals is but one part.

[0010] STATEMENT OF INVENTION

[0011] The invention according to one or more aspects is as defined in the independent claims. Some optional and / or preferred features of the invention are defined in the dependent claims.

[0012] Accordingly, in one aspect of the invention there is provided a locking assembly for releasably attaching a ground engaging tool (GET) to a support member, comprising a body configured to be inserted into a recess formed in the GET, the body comprising: a central body having an end configured to abut with a boss member formed on a surface of the support member, and an internal bore; an actuator screw configured screwingly engage with the central body so as to be at least partially received within the internal bore of the central body and movable to extend into and out of the internal bore of the central body; and an outer shell configured to extend at least partially over the central body and the actuator screw, the outer shell being mounted with respect to the actuator screw such that movement of the actuator screw in a direction out of the internal bore of the central body causes the outer shell to move with the actuator screw; wherein, to secure the GET to the support member the body is inserted into the recess of the GET such that the end of the central body abuts with the boss member and a reaction plate is inserted within a slot formed in the GET to be positioned behind the body, and wherein the actuator screw is screwingly actuated to extend from the internal bore of the central body to pass through a recess formed in the reaction plate such that the outer shell engages with a surface of the reaction plate to generate a force extending through the body between the boss member and the reaction plate to retain the GET in position with respect to the support member.

[0013] In order to release the GET from the support member the actuator screw may be screwingly actuated to retract into internal bore of the central body to remove the force extending through the body between the boss member and the reaction plate.

[0014] The outer shell may sealingly engage with the central body and the actuator screw.

[0015] The outer shell may sealingly engage with the central body and the actuator screw by way of one or more O-rings to form a sealed environment about the actuator screw.

[0016] The central body may be attached to the outer shell to prevent rotational movement of the central body with respect to the outer shell.

[0017] The central body may be attached to the outer shell by a key member extending at least partially through a wall of the outer shell to be received in a longitudinally extending groove formed in an outer surface of the central body.

[0018] The outer shell may be open at opposing ends thereof to accommodate movement of the central body and the actuator screw out of the opposing ends thereof.

[0019] The body may be inserted into a longitudinally extending recess formed in the GET.

[0020] The body may be slidably inserted into the longitudinally extending recess.

[0021] When the actuator screw passes through the recess formed in the reaction plate, the reaction plate may be locked in position with respect to the GET.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention may be better understood from the following non-limiting description of preferred embodiments, in which:

[0024] Fig. 1 is a perspective view of lip plate assembly with a GET affixed thereto in accordance with an embodiment of the present invention; Fig. 2 is an enlarged view of the GET attached to the lip plate of Fig. 1;

[0025] Fig. 3 is a partially removed perspective view of a lock assembly in accordance with an embodiment of the present invention;

[0026] Fig. 4 is a sectional view of the lock assembly of Fig. 3;

[0027] Fig. 5 is an end view of the lock assembly of Fig. 3;

[0028] Figs. 6 - 8 show sectional views of the system of the present invention used to attach a GET to a lip plate; and

[0029] Figs. 9 - 11 show sectional views of the system of the present invention used to detach a GET from a lip plate.

[0030] DETAIEED DESCRIPTION OF THE DRAWINGS

[0031] Preferred features of the present invention will now be described with particular reference to the accompanying drawings. However, it is to be understood that the features illustrated in and described with reference to the drawings are not to be construed as limiting on the scope of the invention.

[0032] The present invention will be described below in relation to a ground engaging tool (GET) in the form of a wear tooth that is attachable to a lip plate of a loader bucket. For reasons of retaining clarity, in the embodiment of the invention depicted, only one GET is shown attached to the lip plate; however, it will be appreciated that there may be multiple GETs attached along the edge of the lip plate assembly 12 as will be appreciated by those skilled in the art. Further, whilst the present invention is depicted as securing a wear tooth to a lip plate of an loader bucket, the present invention could be used to secure any type of GET or other device to a tool holding device, as will be appreciated by those skilled in the art.

[0033] Referring to Fig. 1 and Fig. 2, a lip plate assembly 12 of a loader device is depicted in isolation. The lip plate assembly 12 comprises a front plate 13 formed from a bevelled upper face 13a and substantially horizontally extending lower face 13b, such that the upper face 13a and lower face 13b form a substantially pointed edge upon which the GET 10 is mounted. In this arrangement, the GET 10 extends beyond a front edge of the plate 13 and has a tooth-like configuration to engage with a ground surface in a manner well known in the art. A plurality of boss members 14 are provided upon an upper surface of the lip plate assembly 12, so as to be spaced across the lip plate assembly 12 as shown. Each boss member 14 is fixed, typically welded, to the upper surface of the lip plate assembly 12 and has a head portion 14a located adjacent the front edge of the plate 13 and a tail portion 14b extending away from the head portion 14a. The tail portion 14b terminating in a substantially upright end face 14c, as will be described in more detail below.

[0034] The GET 10 has a blade portion 18 that defines the portion of the GET 10 that projects from the front edge of the plate 13 and a tail portion 19 that extends from a rear of the blade portion 18 to be located on the surface of the lip plate assembly 12, as shown more clearly in Fig. 2. The blade portion 18 has an internal groove 17 formed therein to receive the front edge of the lip plate assembly 12, such that the GET 10 is fittingly located on the front edge of the lip plate assembly 12.

[0035] In the manner as shown in Fig. 2, the GET 10 is positioned on the lip plate assembly 12 such that the tail portion 19 is located over the boss member 14. The end of the tail portion 19 has an opening 16 formed therein that accesses a recess that extends through the tail portion 19 and terminates at the end of the blade portion 18. In this regard, the boss member 14 is received in this recess, as will be discussed in more detail below. The upper surface of the tail portion 19 has a slotted opening 15 formed therein, which will also be described in more detail below.

[0036] A lock assembly 20 for securely locating the GET 10 to the lip plate assembly 12 is depicted in isolation in Figs. 3 - 5. The lock assembly 20 is in the form of a substantially rectangular body that is configured to be received within the opening 16 formed in the tail portion 19 of the GET 10. As is shown in Fig. 3, the lock assembly 20 may be configured with a chamfer formed on a leading edge thereof to provide clearance on a weld on the boss member 14 when in the assembled position, as is discussed below. It will be appreciated that the shape of the lock assembly 20 may vary and will be dependent upon the shape of the opening 16 and central recess formed in the tail portion 19 of the GET 10 to permit a snug fit of the lock assembly 20 therein. The lock assembly 20 comprises a central body 21 having an internal bore 22 that is open at a proximal end and has an internal thread formed therein. The distal end of the central body 21 has a substantially flat end surface that is configured to abut with the end face An actuator screw 24 engages with the central body 21, the actuator screw 24 has an integral shaft portion 25 that extends from a head portion 26. The shaft portion 25 is configured to be received within the internal bore 22 of the central actuator 21 and has an external thread formed thereon to screwingly engage with the internal thread of the internal bore 22. As will be discussed in more detail below, the actuator screw 24 is able to move into and out of the internal bore 22 of the central body 21 by applying a rotational motion to the head portion 26 of the actuator screw 24. The head portion 26 has a lip portion 28 that has a diameter greater than the diameter of the shaft portion 25, such that the lip portion 28 is able to abut with the proximal end of the central body 21 to stop further movement of the actuator screw into the internal bore 22 of the central body 21. The end of the head portion 26 has a central recess 27 formed therein to receive a tool for applying rotational motion to the actuator screw to facilitate the movement of the shaft portion 25 into and out of the internal bore 22 of the central body 21. In the embodiment as shown the central recess 27 has a hexagonal configuration, however the central recess may take a variety of forms for use with a variety of different drive tools as required.

[0037] An outer shell 29 is positioned around the actuator screw 24 and the central body 21, as shown more clearly in Fig. 5. As is shown in Fig. 4, the outer shell 29 has an internal bore 30 that receives the central body 21 and the lip portion 28 of the head portion 26 of the actuator screw 24. The internal bore 30 of the outer shell 29 has an angled step 31 formed therein to reduce the diameter of the internal bore 30 at the proximal end thereof. The angled step 31 has an angle that is the same as the angled front surface of the lip portion 28 of the head portion 26 of the actuator screw 24. As such, any retracting movement of the actuator screw 24 out of the internal bore 22 of the central body 21 will cause the angled front surface of the lip portion 28 of the actuator screw 24 to act against the angled step 31 of the outer shell 29, thereby causing the outer shell 29 to move with the actuator screw 24, with respect to the central body 21. In this regard, the internal bore 30 of the outer shell 29 is free to slide over the outer surface of the central body 21. To maintain this sliding motion of the outer shell 29 with respect to the central body 21, a first seal 32 is provided in a groove formed in the outer surface of the central body 21 adjacent the proximal end thereof. The seal 32 is preferably in the form of an o-ring, although other types of sealing members are also envisaged. A second seal 33 is provided between the inner surface of the outer shell 29 and the head portion 26 of the actuator screw 24 at a point immediately preceding the angled front surface of the lip portion 28. The provision of the first and second seals 32, 33 isolates the internal parts of the lock assembly 20 to ensures that the actuator screw 24 and the central body 21 can freely move within the outer shell 29 without being jammed by the presence of dirt or other particulate matter entering the sealed environment.

[0038] As is shown more clearly in Fig. 3, in order to prevent the central body 21 from rotating with the actuator screw 24 when rotational motion is applied thereto, a key member 40 is provided. The key member 40 may be in the form of a screw or dowel, or other similar component, that extends through the outer shell 29 and is received in a longitudinally extending groove 42 formed in the outer surface of the central body 21. This allows the central body 21 to slide in a longitudinal direction within the outer shell 29 but prevents the central body 21 from moving in a rotational manner within the outer shell 29, such that rotational motion applied to the screw actuator 24 can cause the central body 21 to move in a longitudinal direction, as will be more apparent below.

[0039] The manner in which the lock assembly 20 functions to lock the GET 10 to the lip plate 12 will be described below in reference to Figs. 6 - 8.

[0040] As shown in Fig. 6, to install the GET 10, the GET 10 is pushed on to the front edge of the lip plate assembly 12, such that the boss member 14 is received within the recess formed in the tail portion 19 of the GET 10. The lock assembly 20 is then inserted into the opening 16 formed in a rear face of the tail portion 19 of the GET such that it can be pushed into the recess formed in the tail portion 19 until the distal end of the central actuator 21 of the lock assembly abuts the rear face of the boss member 14, as shown.

[0041] As is shown in Fig. 7, in this position, a reaction plate 35 is inserted through the slotted opening 15 formed in the upper surface of the tail portion 19 of the GET 10. The reaction plate 35 has a substantially rectangular shape with a central recess formed therein to accommodate the proximal end of the head portion 26 of the actuator screw 24. When initially positioned in place in the manner as depicted in Fig. 7, the reaction plate is located behind the lock assembly 20.

[0042] To secure the GET 10 in position, the actuator screw 24 is then rotated in a clockwise direction such that it is caused to extend from the central body 21, in the manner as shown in Fig. 8. As the actuator screw 24 extends from the internal bore 22 of the central body 21, it draws the outer shell 29 back towards the reaction plate 35, due to the interaction between the angled front surface of the lip portion 28 and the angled step 31 formed in the bore of the outer shell 29. As the actuator screw 24 continues to retract from the internal bore 22 of the central body 21, the head portion 26 of the actuator screw 24 is received within the central recess of the reaction plate 35, thereby locking the reaction plate 35 in position and preventing the reaction plate 35 from being removed from the GET

[0043] 10. Continual retraction of the actuator screw 24 from the central body 21 will move the outer shell 29 to contact the surface of the reaction plate 35 and apply a force against the reaction plate 35. As the distal end of the central body 21 comes into contact with the end face 14c of the boss member 24, a force is generated between the boss member 24 and the reaction plate 25 by way of the actuator screw 24 and the central body 21. This force is sufficient to retain the GET 10 in a working position on the front edge 13 of the lip plate 12.

[0044] To replace the GET 10 following wear or failure, reference is made to Figs. 9 -

[0045] 11.

[0046] In Fig. 9, the actuator screw 24 is rotated in a counter-clockwise direction to retract the actuator screw 24 back into the internal bore 22 of the central body 21, as shown. This causes the head portion 26 of the screw actuator to pass back through the central recess in the reaction plate 35 and the outer shell 29 to lose pressure contact with the reaction plate 35, thereby removing the retaining force holding the GET in position. The reaction plate 35 can then be removed through the slotted opening 15 formed in the upper surface of the tail portion 19 of the GET 10, as shown in Fig. 10. A lever, such as a jimmy bar, can be inserted into the opening 15 to assist in removing the reaction plate 35.

[0047] To remove some of the operational induced retention forces created by fine particles present between the outer shell 29 and the inner surface of the tail portion 19 of the GET 10, the actuator screw 24 may be rotated in a clockwise direction to cause the actuator screw 24 to extend out from the internal bore 22 of the central body 21. This will result in the outer shell 29 extending out towards the rear of the tail portion 19 of the GET 10, thus breaking some of the operational induced retention forces that may have built up between the outer shell 29 and the GET 10. Slide hammers and other such tools can also be used to grip the screw 24 to facilitate removal of the lock assembly. The lock assembly 20 can then be removed as shown in Fig. 11 and the GET 10 can be removed from the front of the lip plate 12 in a reverse process to its fitment, for replacement as necessary.

[0048] It will be appreciated that the lock assembly of the present invention provides for a simple device that can be inserted into a GET and which can at least partially pull itself from within the cavity of the GET, thus breaking any frictional forces that may generate within the system and making items easier to remove in the field.

[0049] Further to this, the system of the present invention is configured to isolate the moving parts of the device to form a contaminant free environment for the parts to operate in a simple and effective two-piece locking assembly. Throughout the specification and claims the word “comprise” and its derivatives are intended to have an inclusive rather than exclusive meaning unless the contrary is expressly stated or the context requires otherwise. That is, the word “comprise” and its derivatives will be taken to indicate the inclusion of not only the listed components, steps or features that it directly references, but also other components, steps or features not specifically listed, unless the contrary is expressly stated or the context requires otherwise.

[0050] It will be appreciated by those skilled in the art that many modifications and variations may be made to the methods of the invention described herein without departing from the spirit and scope of the invention.

Claims

The claims defining the invention are as follows:

1. A locking assembly for releasably attaching a ground engaging tool (GET) to a support member, comprising a body configured to be inserted into a recess formed in the GET, the body comprising: a central body having an end configured to abut with a boss member formed on a surface of the support member, and an internal bore; an actuator screw configured to screwingly engage with the central body so as to be at least partially received within the internal bore of the central body and movable to extend into and out of the internal bore of the central body; and an outer shell configured to extend at least partially over the central body and the actuator screw, the outer shell being mounted with respect to the actuator screw such that movement of the actuator screw in a direction out of the internal bore of the central body causes the outer shell to move with the actuator screw; wherein, to secure the GET to the support member the body is inserted into the recess of the GET such that the end of the central body abuts with the boss member and a reaction plate is inserted within a slot formed in the GET to be positioned behind the body, and wherein the actuator screw is screwingly actuated to extend from the internal bore of the central body to pass through a recess formed in the reaction plate such that the outer shell engages with a surface of the reaction plate to generate a force extending through the body between the boss member and the reaction plate to retain GET in position with respect to the support member.

2. A locking assembly according to claim 1, wherein to release the GET from the support member the actuator screw is screwingly actuated to retract into internal bore of the central body to remove the force extending through the body between the boss member and the reaction plate.

3. A locking assembly according to claim 1 or claim 2, wherein the outer shell sealingly engages with the central body and the actuator screw.

4. A locking assembly according to claim 3, wherein the outer shell sealingly engages with the central body and the actuator screw by way of one or more O-rings to form a sealed environment about the actuator screw.

5. A locking assembly according to any one of the preceding claims, wherein the central body is attached to the outer shell to prevent rotational movement of the central body with respect to the outer shell.

6. A locking assembly according to claim 5, wherein the central body is attached to the outer shell by a key member extending at least partially through a wall of the outer shell to be received in a longitudinally extending groove formed in an outer surface of the central body.

7. A locking assembly according to claim 1, wherein the outer shell is open at opposing ends thereof to accommodate movement of the central body and the actuator screw out of the opposing ends thereof.

8. A locking assembly according to claim 1, wherein the body is inserted into a longitudinally extending recess formed in the GET.

9. A locking assembly according to claim 8, wherein the body is slidably inserted into the longitudinally extending recess.

10. A locking assembly according to claim 1, wherein when the actuator screw passes through the recess formed in the reaction plate, the reaction plate is locked in position with respect to the GET.

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