Patent Application
20150013197
The present disclosure relates generally to a tool retention system and, more particularly, to a wear collar for a tool retention system.
Earth-working machines, such as cable shovels, excavators, wheel loaders, draglines, and front shovels, include implements generally used for digging into, ripping, or otherwise moving earthen material. These implements are subjected to extreme abrasion and impacts that causes them to wear. To prolong the useful life of the implements, various ground engaging tools can be connected to the earth-working implements at areas experiencing the most wear. These ground engaging tools are replaceably connected to the implements using a retention system.
An exemplary system for retaining a ground engaging tool connected to an implement is disclosed in U.S. Pat. No. 8,468,724 of Leslie et al. that issued on Jun. 25, 2013 (“the '724 patent”). Specifically, the '724 patent discloses a retaining pin assembly having opposable locating members, each with a shank portion able to be slidably inserted into opposing sides of a wear member and into a mounting nose of an excavator bucket. Each locating member also has an enlarged wedge portion adjacent a normally-outer end. A bolt extends between the locating members from one side of the retaining pin assembly. When tension is applied to the bolt, relative contraction of the locating members occurs. This contraction urges the wear member into engagement with the mounting nose by engagement of each of the wedge portions with a rear wall of respective retaining pin apertures.
Although acceptable for some applications, the retaining pin assembly of the '724 patent may be less than optimal. In particular, over time, the retaining pin apertures and/or the wedge portions can wear, resulting in loosening of the wear member from the mounting nose. Although additional tensioning of the bolt may re-tighten this engagement, eventually enough wear may occur such that additional tensioning is not possible. When this occurs, the retaining pin assembly and/or the wear member or mounting nose must be replaced. This replacement can be time consuming and costly.
The disclosed wear collar and tool retention system are directed to overcoming one or more of the problems set forth above.
According to one exemplary aspect, the present disclosure is directed to a wear collar for a tool retention system having a locating member with a wedge portion. The wear collar may include a hollow body at least partially forming an inner surface configured to mate against an external surface of the locating member at the wedge portion, and an outer surface offset from the inner surface. The outer surface may have a profile generally matching a profile of the inner surface. The hollow body may be configured to receive and annularly surround the locating member.
According to another exemplary aspect, the present disclosure is directed to a wear collar kit for a tool retention system having a locating member with a wedge portion. The wear collar kit may include at least a first wear collar connectable to the wedge portion of the locating member and being configured to limit relative movement between a tool adapter and a mounting nose of a work implement by a first amount. The wear collar kit may also include at least a second wear collar connectable to the wedge portion of the locating member and being configured to limit relative movement between a tool adapter and the mounting nose of the work implement by a second amount greater than the first amount.
According to another exemplary aspect, the present disclosure is directed to a tool retention system. The tool retention system may include at least one locating member having a wedge portion and a shank portion extending from the wedge portion. The shank portion may be configured to be slidably inserted into a side of an adapter and into a mounting nose of a work implement. The tool retention system may also include a bolt configured to engage an end of the shank portion opposite the wedge portion. Tension of the bolt may cause the wedge portion to urge the adapter into further engagement with the mounting nose. The tool retention system may further include at least one wear collar having a first axial end, an opposing second axial end, and an inner surface extending from the first axial end to the second axial end. The inner surface may be configured to mate against an external surface of the at least one locating member at the wedge portion. The tool retention system may additionally include an outer surface offset from the inner surface and having a profile generally matching a profile of the inner surface. The inner surface of the wear collar may receive and annularly surround the at least one locating member, and the wear collar may extend in an axial direction a majority length of the wedge portion. The inner surface at the first axial end may be generally elliptical, and the inner surface at the second axial end may be generally circular.
According to another exemplary aspect, the present disclosure is directed to a method of servicing a tool retention system. The method may include removing tension from a bolt to release a locating member connecting an adapter to a mounting nose of a work implement, and removing the locating member from corresponding apertures in the adapter and the mounting nose of the work implement. The method may also include installing a wear collar over a wedge portion of the locating member, and inserting the locating member and the wear collar back through the corresponding apertures. The method may further include re-tensioning the bolt to increase engagement of the adapter to the mounting nose of the work implement.
Work implement 12 may embody any device used to perform a particular task such as, for example, a bucket (shown in
Work implement 12 may be equipped with one or more ground engaging tools (GET) 14 located at a cutting edge 16. For example, the disclosed bucket could be provided with multiple similar tooth assemblies that are spaced apart along a length of cutting edge 16. While shown as single-point, sharpened tooth assemblies, it is contemplated that GET 14 could take any other form known in the art, for example a fork (i.e., multi-point) configuration, a chisel configuration, or a blunt-end configuration.
GET 14 may be a conventional multi-piece component that is removably connected to work implement 12. In the embodiment shown in
Adapter 20 may be a generally hollow structural member having a base end 28 located opposite nose end 26. Base end 28 may be configured to receive mounting nose 22 of work implement 12, while nose end 26 may be received within tip 18. A pair of aligned apertures 30 (only one shown in
Retention system 24 may include components that interact to clamp an associated GET 14 in a removable manner to mounting nose 22 at cutting edge 16 of work implement 12. Specifically, retention system 24 may include one or more locating members 37, a bolt 38, and a wear collar 40. In the embodiment of
As shown in
Wedge portion 44 may have a single axially-oriented plane of symmetry 58, which passes through a center of outer surface 52. This configuration of locating member 37 may allow for insertion within apertures 30, 34 in only a single orientation, and help to inhibit rotation of locating member 37 after assembly and during operation.
As can also be seen in
Like locating member 37, wear collar 40 may have a single plane of symmetry configured to align with plane 58 once assembled, such that once locating member 37 is inserted into wear collar 40, the singular-symmetry of these components may help to resist relative rotation therebetween. Plane 58 may pass through inner surface 62 at two spaced apart locations. At a first of these locations (lower-left location shown in
Body 60 of wear collar 40 may also include a first or outer axial end 66 located at chamfered edge 54, and an opposing second or inner axial end 68 located at transition 50. In the disclosed embodiment, inner surface 62 at first axial end 66 has a shape that is generally elliptical, while inner surface 62 at second axial end 68 has a shape that is generally circular. It is contemplated, however, that inner surface 62 at both of first and second ends 66, 68 could alternatively be elliptically shaped, if desired. In either configuration, inner surface 62 at first axial end 66 may have a small diameter D1 that is about equal to a small diameter d1 of inner surface 62 at second axial end 68, and a large diameter D2 that is about 10-30% larger than a large diameter d2 of inner surface 62 at second axial end 68. This geometrical relationship may provide a thickness to inner diameter ratio of about 1:3-4 at second axial end 68 and a thickness to axial length ratio of about 1:2.5-3.5, which may help ensure adequate strength and proper fit within worn apertures 30, 34. Wear collar 40 may be made from a material that is substantially identical to a material from which locating member 37 is fabricated, such that wear collar 40 may wear and provide support in a substantially identical manner as locating member 37. In other embodiments, wear collar 40 may be made from a material that is different than the material from which locating member 37 is fabricated, so that the wear collar 40 provides improved wear resistance as compared to the locating member 37 absent a wear collar.
After a period of operation, different components of work implement 12, GET 14, and/or retention system 24 may wear. As will be described in more detail below, wear collars 40 may be selectively assembled around worn locating members 37 to accommodate this wear and help ensure the appropriate engagement conditions between GET 14 and work implement 12. It may be possible, however, for the wear to be more severe in some applications than in others, and/or for the wear to be dependent on an age or usage period of machine 10. To accommodate the different applications and/or worksite conditions, a wear collar kit may be created having multiple different wear collars 40. This kit may include multiple sets of two wear collars 40 each, each set having a different thickness t configured to limit relative movement between adapter 20 and mounting nose 22 by different amounts (e.g., a first collar for initial wear and a second collar that is about 10% thicker for accommodating more severe wear). In addition, the kit may include instructions for removing locating members 37 and/or existing wear collars 40, and for assembling replacement wear collars 40 having a different thickness. The kit may have a single part number, meaning that the kit can be ordered and distributed as a single sales item to consumers. In some embodiments, a replacement bolt 38 and/or seals (not shown) may also be included in the kit, if desired.
An alternative retention system 70 is shown in
As shown in
Wear collar 78 of
The disclosed wear collar and tool retention system may be applicable to various earth-working machines, such as cable shovels, wheel loaders, excavators, front shovels, dredges, and bulldozers. When used to removably connect ground engaging tools to the work implements of these machines, the work implements may be protected against wear in areas experiencing damaging abrasions and impacts. Accordingly, the disclosed tool retention system may help to prolong the useful life of the implements and the machines. Use of tool retention system 24 to improve connection of GET 14 to work implement 12 after a period of operation and wear will now be described in detail.
After a period of operation, the engagement between work implement 12 and GET 14 may become loose due to abrasive wear. If unaccounted for, continued use under these conditions could result in costly damage of these components. Accordingly, a service technician may periodically check the engagement between work implement 12 and GET 14. When significant movement between work implement 12 and GET 14 is observed (i.e., an amount about a threshold level), the service technician may remove and service retention system 24.
The service technician may remove retention system 24 by releasing tension within bolt 38. In some embodiments, a plug (not shown) may need to be removed to gain access to a head end of bolt 38. Once the tension of bolt 38 is released, one or both of locating members 37 may be removed from (i.e., knocked out of) apertures 30, 34. Depending on the amount of wear that has occurred, the service technician may select for use one or more wear collars 40 (from the kit described above) that have a corresponding thickness. Wear collar(s) 40 may then be installed over the removed and worn locating member(s) 37, and then the locating member(s) 37 and wear collar(s) 40 may be inserted back through the corresponding apertures 30, 34. Bolt 38 may then be re-tensioned to increase the engagement of adapter 20 with mounting nose 22 of work implement 12.
After another period of wear, the previously installed wear collar(s) 40 may need to be replaced with different wear collar(s) 40 from the kit having a greater thickness. This process may be completed in much the same way described above. In particular, tension in bolt 38 may be released, the corresponding locating member(s) 37 removed, the previously installed wear collar(s) 40 removed from locating member(s) 37, the thicker wear collar(s) 40 installed, and everything put back together. It is contemplated, however, that in some embodiments, rather than removing a worn wear collar 40, an additional wear collar 40 may simply be installed over the existing worn wear collar 40, if desired. Servicing of retention system 70 may be performed in the same manner as described above.
The disclosed retention system(s) may be relatively simple and low-cost. Specifically, because worn components may continue to be used, augmented with wear collars 40, the operating cost of machine 10 may be low. In addition, because excessive wear can be absorbed with wear collars 40, damage to more expensive components of machine 10 may be avoided.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed wear collar and retention systems. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed wear collar and retention systems. For example, although wear collars 40 and 78 are described as being used only after other components of GET 14 and/or retention system 24 have worn, it is contemplated that wear collars 40, 78 could alternatively be used in a new configuration and then replaced as they themselves wear out. In this manner, other components of GET 14 and/or retention system 24 may experience less initial wear. It is further contemplated that wear collars 40, 78 could be made of softer materials, allowing a majority of wear to occur therein as opposed to within other mating components. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.
