WO2005108684A1

WO2005108684A1 - Locking assembly for ground engaging tools

Info

Publication number: WO2005108684A1
Application number: PCT/CA2004/002013
Authority: WO
Inventors: Dwight L. Adamic
Original assignee: Qsf Acquisitions Inc.
Priority date: 2004-05-10
Filing date: 2004-11-23
Publication date: 2005-11-17
Also published as: CA2466768A1

Abstract

The present invention provides a locking assembly for releasably locking a ground engaging wear member to a base structure. The wear member and the base structure both have passages extending through them and positioned to form a contiguous channel having a recessed cavity when the wear member and base structure are operatively assembled. The locking assembly comprises a resilient pin retainer sized for placement in the recessed cavity and having a central passage with a locking element. The central passage is positioned for alignment with the contiguous channel when the pin retainer is placed in the recessed cavity. The locking assembly also comprises a pin, radially sized for passage through the contiguous channel and the central passage. The pin has a complementary locking element for engaging the locking element in the central passage to impede axial motion of the pin through the channel in at least one direction, for engaging the passage of the wear member and base structure to lock the wear member to the base structure.

Description

LOCKING ASSEMBLY FOR GROUND ENGAGING TOOLS

FIELD OF THE INVENTION The present invention relates generally to ground engaging tools. More particularly, the present invention relates to locking mechanisms for retaining ground engaging members onto support structures.

BACKGROUND OF THE INVENTION Ground-engaging tools generally employ replaceable wear members. These wear members are locked to support structures, such as adapters or bases, which attach the wear member to the tool. The wear members frequently need to be replaced during operation of the ground engaging tool, and therefore, the lock mechanism must be easy and simple to use to minimize downtime of the equipment. A ground-engaging tool typically has a support structure attached to its digging lip. Conventionally, support structures are typically locked onto the lips through the use of a weld or a wedge-and-spool device. Most of these support structures have centrally located channels extending through them to correspond to openings in opposing walls of a wear member. This configuration is well suited for older-type locking mechanisms rather than newer locking mechanisms. One such common locking mechanism is the wedge and spool-type lock. This lock is comprised of two pieces that are driven by hammer into a channel through the wear member and the support structure on which it was placed. Several disadvantages arise with this type of lock. The wedge-and-spool components sometimes shatter due to impact during installation or removal, which endangers nearby workers. Additionally, to secure the locking mechanism in place, the components are often spot-welded together to ensure they do not come loose during use of the tool. The use of a spot weld makes removal of ^■ the wear member difficult, requiring extended down time for replacement of wear members. Another common locking mechanism is the pin and retainer-type lock. This lock is comprised of an elongated notched pin and a pin retainer. The pin is driven into a channel through the wear member and the support structure until the pin notch engages the pin retainer, which is held in place by the wear member and/or support structure. Over the years many different shapes have been used for the pin and retainer, but they all share a tendency to provide insecure locking under high digging loads, and for the worn locks to be difficult to remove. Thus there is a need for a modern coupling system to attach new ground-engaging wear members, such as points or adapters, to older-style support structures, without the need to retrofit the support structures for more modern coupling systems. There is also a need for such an assembly which is safe and easy for workers to use.

SUMMARY OF THE INVENTION It is an object of the present invention to obviate or mitigate at least one disadvantage of prior art locking assemblies used to secure wear members to support structures such as adapters or adapter bases. The present invention provides a locking assembly for retaining a first workpiece onto a base or second workpiece. It is preferably used to retain a ground-engaging wear member on to a support structure such as an adapter or an adapter base but it is also suitable for comparable workpieces. In one aspect, the present invention provides a locking assembly for releasably locking a first member to a support structure. The first member and the support structure both have passages extending through them and positioned to form a contiguous channel having a recessed cavity when the first member and support structure are operatively assembled. The locking assembly comprises a resilient pin retainer sized for placement in the recessed cavity and having a central passage with a locking element. The central passage is positioned for alignment with the contiguous channel when the pin retainer is placed in the recessed cavity. The locking assembly also comprises a pin, radially sized for passage through the contiguous channel and the central passage. The pin has a complementary locking element for engaging the locking element in the central passage to impede axial motion of the pin through the channel in at least one direction, for engaging the passage of the first member and support structure to lock the first member to the support structure. Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:

Figure 1 is a perspective view of a model of the pin of the present invention; Figure 2 is a perspective view of a model of the pin retainer of the present invention;

Figure 3 A shows a side perspective view of a ground-engaging wear member;

Figure 3B shows an end perspective view of a ground-engaging wear member;

Figure 4 is a perspective view of a model of the present invention assembled with a ground-engaging wear member and adapter; Figure 5 is a side schematic view of the pin of the present invention;

Figure 6 is an end view of the pin of Figure 5;

Figure 7 is a cross-sectional view taken at line A- A in Figure 5;

Figure 8 is a further side view of the pin of Figure 5 showing the side which is adapted to hold a resilient member; Figure 9 is an enlarged section of view B-B from Figure 8;

Figure 10 is a side view of the pin retainer shown in Figure 2;

Figure 11 is a top view of the pin retainer shown in Figure 10;

Figure 12 is a side cross-sectional view of the pin retainer of Figure 10;

Figure 13 is a cross-sectional view of a wear member and adapter assembly utilizing the pin and retainer of the present invention;

Figure 14 is an enlarged view taken at section H in Figure 13; and

Figure 15 is a top view of a further embodiment of the pin retainer.

DETAILED DESCRIPTION Generally, the present invention provides a method and system for locking a wear member to a support structure. With reference to the Figures, the lock assembly of one embodiment of the present invention comprises a pin 1, pin retainer 3, and resilient locking member 5 as are shown in Figures 1 and 2. The lock assembly is preferably used with ground-engaging tools having wear members mounted on to adapters to act as sheathes covering the adapters. It may however be used for other assemblies requiring the locking of any first work piece to a support structure or second work piece. An example of a wear member 7 and an adapter 9 are shown in Figures 3A, 3B and 4. The wear member 7 has an end W which engages the ground and an end A having a cavity fitting over the nose of an adapter. Near the end A, the wear member has two openings 8 forming passages, on opposing sides. In at least one of these passages, the wear member 7 has a cavity 10 in its inner surface for receiving the pin retainer 3 (shown in position in Figure 3B). In an alternative embodiment, the pin retainer-receiving cavity is on the adapter nose rather than the inner surface of the wear member. The adapter 9 has a passage aligned with the passages 8 in the wear member. This alignment forms a locking channel that receives a locking assembly to hold the wear member 7 to the adapter 9. The wear member 7 thus sheathes the adapter 9 to prevent undue wear of the adapter 9. When assembled as is shown in Figure 4, the pin extends through these passages in the wear member 7 and the adapter 9, and through the pin retainer 3 to retain the wear member in locking engagement with the adapter. The pin is shown in more detail in Figures 1, and 5-9. The pin is generally elongated along longitudinal axis CL as shown in Figures 5 and 8. It is preferably non- circular, with a rectangular, octagonal, or similar cross-section, to prevent it from rotating in the passage. As shown in Figure 1, each end of the pin is preferably substantially flat in a plane substantially perpendicular to the longitudinal axis. It is intended that the ends of the pin will be flush with, or recessed from, the outer surface of the wear member when fully inserted into the locking channel. In a presently preferred embodiment, the pin will not extend beyond the outer surfaces of the wear member when inserted into the locking channel. One end of the pin is preferably tapered having a generally frusticonical shape. Such a shape allows for easy insertion of the pin through the passages in the wear member and adapter. At the opposing end, the pin optionally has a recess in the flat surface to allow a worker to insert a tool to aid in the insertion and removal of the pin. This recess is shown in more detail in Figures 6 and 8. The recess is provided to help hold a tool, such as a punch, in place while a worker hammers on the end of the tool to force the pin into position or to force the pin through the passages to remove it. As shown in Figures 1, 5, 7 and 8, the pin preferably has a recess extending along one side in the longitudinal direction CL. This recess houses the resilient locking member. The resilient locking member is preferably inserted into the recess so that its ends extend into channels at either end of the recess, as shown in Figure 8. The engagement of the ends of the resilient locking member and the channels hold the resilient locking member in position. One skilled in the art will appreciate that there are a number of other mechanisms, known in the art, for securing the resilient locking member to the pin that do not depart from the scope of the present invention. A portion of the resilient lock member extends outward from the pin. The resilient locking member is deformed as the pin progresses through the locking channel. When the pin is secured in the locking channel, the locking member provides additional frictional engagement with adapter 9. Near the second end C of the pin are slots extending across the pin in a lateral direction. The embodiment shown in Figures 2, 8 and 9, has a set of locking elements or slots extending across two opposing sides of the pin with the resilient locking member on a side of the pin between these slots. Although three slots on each side are shown in the Figures, any number may be used. As well, these slots may continue around the perimeter of the pin. In one embodiment, these slots extend into the pin body at about a 45° angle as is shown in more detail in Figure 8. However, any number of slots and appropriate angle corresponding to the number and angle of matching slots on the pin retainer may be used. A pin retainer of the present invention is shown in Figures 2, 10 to 12. It is a removable retainer which is inserted into the cavity in the inner surface of the wear member. The pin retainer is shown inserted into the cavity in the wear, or sheathing, member in Figures 3B, 4, 13 and 14. Alternatively, it may be placed in a cavity in the adapter. It is preferably made from a resilient material. In the illustrated embodiment, the retainer has a generally rectangular outer shape. This prevents it from rotating in its retaining cavity. In other embodiments, the retainer can have any suitable shape to fit the retaining cavity. Preferably, the shape is non-circular to prevent rotation within the cavity. The retainer shown in Figures 2, 10 and 14 has an optional lip extending along its lower edge. This lip is received into a corresponding recess at the opening of the cavity in the wear member to help place the retainer in the cavity and hold it in position. Other protrusions may also extend from the outer surface of the retainer to hold the retainer in place in the wear member prior to placement of the wear member on the adapter. An example is shown in Figure 15. In this example, the semi-circumferential lip on the retainer has been removed. Instead, this retainer has a wedge-shaped protrusion 21 on the outer surface of each side of the retainer. The retainer cavity in the wear member would have similar wedge-shaped recesses to hold the retainer in place. The positioning of the wear member onto the working end of the adapter will position the outer, lower surface of the retainer against the outer surface of the adapter. The walls of the cavity in the wear member as well as the outer surface of the adapter will therefore hold the pin retainer in position during use. The retainer has complementary locking elements on its inner surface to correspond to the locking elements on the pin. These complementary locking elements are shown in more detail in Figure 12. These complementary locking elements are formed from protrusions on the inner surface of the retainer extending into the passage in the retainer. They correspond to and fit into the slots on the pin. These locking elements slope toward the adapter in a "downward" direction. One skilled in the art will appreciate that at least one of either the locking elements on the pin, or the complementary locking elements in the retainer, should be resilient, so that the pin can be inserted under pressure, but further movement is impeded in one direction, and preferably prevented in the other axial direction. To lock a wear member to an adapter, the pin retainer is placed into the retaining cavity on the inner surface of the wear member. The wear member is placed over the working end of adapter. The pin retainer is now held in position and the openings in the wear member align with the passage through the adapter to form the locking channel. The resilient lock member is preferably placed into the longitudinal recess in the pin body. The tapered end of the pin is placed into the opening in the wear member adjacent the pin retainer. The pin is forced into the locking channel. As it moves through the locking channel, the resilient lock member will pass though the pin retainer and into the passage in the adapter. The complementary sets of locking elements on the pin and on the inner surface of the pin retainer will engage each other. Because the complementary sets of locking elements are preferably designed to prevent movement of the pin in one axial direction, the pin cannot be removed from the adapter through the same opening into which it is inserted. Removal of the pin is accomplished by applying pressure on the pin in the same axial direction that the pin entered the locking channel. The pin passes completely through the locking channel for removal. When the second, flat end C of the pin is flush with the outer surface of the wear member or slightly recessed within the opening in the wear member, the sets of complementary locking elements on the pin and in the pin retainer are fully engaged. The resilient lock member is positioned within the passage in the adapter and helps to keep the pin in position by frictional engagement with the adapter in the locking channel. The wear member is now releasably locked to the adapter. During use of the ground-engaging wear member, the forces acting on the wear member to remove it from the adapter will be applied to the pin. The pin retainer does not receive a significant amount of these forces and therefore it may be made of a resilient material, though this is merely preferable and not essential. If the retainer is made to be resilient in its entirety, the pin absorbs the ground-engaging wear member - removal forces since, when forces are applied to the pin, the locking member will be compressed, and the pin will move against the walls of the passage in the adapter. When the ground-engaging wear member is ready to be replaced, the pin is driven through the passages in the wear member and the adapter by application of force at its second, flat end. This force is generally applied by workers using hammers. As the force is applied to the end of the pin, the pin will continue to move through the passage in the same direction it was inserted. The complementary sets of locking elements on the pin and the pin retainer will disengage when they are subjected to sufficient axial force. The above-described embodiments of the present invention are intended to be examples only. Alterations, modifications and variations may be effected to the particular embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto.

Claims

CLAIMS:

1. A locking assembly for releasably locking a first member to a support structure, the first member and the support structure both having passages therethrough positioned to form a contiguous channel, having a recessed cavity extending at least partially around the perimeter of the channel, when the first member and support structure are operatively assembled, the locking assembly comprising: a resilient pin retainer sized for placement in the recessed cavity and having a central passage with a locking element, the central passage positioned for alignment with the contiguous channel when the pin retainer is placed in the recessed cavity; and a pin, radially sized for passage through the contiguous channel and the central passage, having a complementary locking element for engaging the locking element in the central passage to impede axial motion of the pin through the channel in at least one direction, for locking the first member to the support structure.

2. The locking assembly of claim 1 wherein the pin has an axial length less than or substantially equal to the length of the contiguous channel.

3. The locking assembly of claim 1 wherein the locking element in the central passage and the complementary locking element of the pin include an interlocking set of tongues and grooves.

4. The locking assembly of claim 1 further comprising a resilient lock member for attachment to the pin and for frictional engagement with at least one of the first member and the support structure upon insertion of the pin into the contiguous channel.

5. The locking assembly of claim 4 wherein the pin has an opening in its surface extending axially, and wherein the lock member is sized to extend radially upon insertion in the opening in the pin, the radially extending portion of the lock member for frictional engagement with at least one of the first member and the support structure upon insertion of the pin into the contiguous channel.

6. The locking assembly of claim 1 where the pin retainer is non-rotatable within the recessed cavity.

7. The locking assembly of claim 1 wherein the recessed cavity is in the first member.

8. The locking assembly of claim 1 wherein a head end of the pin has an impression sized for receiving a tool used to insert the pin into the channel.

9. The locking assembly of claim 1 wherein the pin is frustoconical.

10. A locking assembly for holding a sheathing member to a support structure in releasable locking engagement, the sheathing member and support structure defining a locking channel having a recessed cavity, when aligned for releasable locking engagement, the assembly comprising: a pin retainer for engagement with the recessed cavity having a central passage positioned for alignment with the locking channel upon engagement of the retainer with the recessed cavity, the pin retainer having a first complementary locking element disposed within the locking channel; and a pin, radially sized for passage through the locking channel, having a second complementary locking element for engaging with the first complementary locking element to prevent movement of the pin in at least one axial direction, and for engaging both the sheathing member and the support structure in the locking channel to releasably lock the sheathing member to the base.

11. The locking assembly of claim 10 further comprising a resilient lock member for attachment to the pin for frictional engagement with at least one of the sheathing member and the support structure upon insertion of the pin into the locking channel.

12. The locking assembly of claim 11 wherein the pin has an opening in its surface extending axially, and wherein the lock member is sized to extend radially upon insertion in the opening in the pin, the radially extending portion of the lock member for frictional engagement with at least one of the sheathing member and the support structure upon insertion of the pin into the locking channel.

13. The locking assembly of claim 10 wherein the first and second complementary locking elements are interlocking set of tongues and grooves.

14. A ground engaging wear member for use with a pin retainer, comprising: an internal surface and an external surface defining at least one wall; an opening extending through said wall; a cavity extending at least partially around said opening for receiving the pin retainer wherein, when the pin retainer is inserted in the cavity, an opening in the pin retainer aligns with the opening in the wear member wall; engaging means to retain the pin retainer in the cavity prior to engagement of the wear member with the support structure.

15. The wear member of claim 14 wherein said engaging means comprises a groove extending circumferentially around the cavity for receiving a corresponding band on the pin retainer.

16. The wear member of claim 15 wherein said engaging means comprises at least one wedge-shaped recess in a wall of the cavity for receiving a corresponding wedge-shaped protrusion on the pin retainer.