Patent Publication Number: US-11035103-B2

Title: Lock for ground engaging tool

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. application Ser. No. 14/959,882, filed Dec. 4, 2015, which claims the benefit of U.S. Provisional Patent Application No. 62/094,693, filed Dec. 19, 2014, both of which are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to a lock for a ground engaging tool and, more particularly, to a lock for removably attaching the ground engaging tool to an earth-working machine. 
     BACKGROUND 
     Earth-working machines, such as, for example, excavators, loaders, hydraulic mining shovels, cable shovels, bucket wheels, bulldozers, and draglines, are generally used for digging or ripping into the earth or rock and/or moving loosened work material from one place to another at a worksite. These earth-working machines include various earth-working implements, such as a bucket or a blade, for excavating or moving the work material. These implements can be subjected to extreme wear from the abrasion and impacts experienced during the earth-working applications. 
     To protect these implements against wear, and thereby prolong the useful life of the implements, various ground engaging tools, such as shrouds, teeth, edge protectors, and other wear members, can be provided on the earth-working implements in the areas where the most damaging abrasions and impacts occur. These ground engaging tools are removably attached to the implements using customized retainer systems, so that worn or damaged ground engaging tools can be readily removed and replaced with new ground engaging tools. 
     Many retainer systems have been proposed and used for removably attaching various ground engaging tools to earth-working implements. One example of such a retainer system is disclosed in U.S. Pat. No. 8,776,408 to Stewart et al. In particular, the &#39;408 patent discloses a protective shroud assembly. The assembly includes a shroud adapted to be fitted to a wear edge having a boss. The assembly also includes a locking means. The locking means includes a cylinder having a cam-like surface extending outwardly from a sidewall of the cylinder. The locking means also includes a compressible member. The cam-like surface is adapted to engage the compressible member as the cylinder is rotatably received in an aperture of the shroud, forcing the compressible member against the boss and retaining the shroud in position with respect to the wear member. 
     The assembly of the &#39;408 patent may provide certain benefits. However, it may have certain drawbacks. For example, material may become lodged between various surfaces of the locking means, making it difficult to remove the shroud from the wear edge. As another example, the locking means itself may be subjected to wear from the abrasion and impacts experienced during earth-working applications. The disclosed embodiments may help solve these and/or other problems known in the art. 
     SUMMARY 
     According to one exemplary aspect, the present disclosure is directed to a lock for a ground engaging tool. The lock may include a body portion including a first diameter. The lock may also include a neck portion, which may include a second diameter smaller than the first diameter. The neck portion may extend from the body portion along a rotational axis of the lock. The lock may also include a head portion, which may extend from the neck portion along the rotational axis. The head portion may include a surface facing the body portion. The lock may be rotationally symmetric about the rotational axis. 
     In another exemplary aspect of the present disclosure, the lock may include a body portion including a first diameter. The lock may also include a neck portion, which may include a second diameter smaller than the first diameter. The neck portion may extend from the body portion. The lock may also include a head portion, which may extend from the neck portion. The head portion may include a bottom surface facing the body portion and a top surface facing away from the body portion. The head portion may also include first and second generally planar end surfaces extending from the bottom surface to the top surface. In addition, the head portion may include first and second cam surfaces extending from the bottom surface to the top surface, and connecting the first and second end surfaces. A portion of the first cam surface adjacent the first generally planar end surface may include a first radius of curvature, and another portion of the first cam surface may include a second radius of curvature larger than the first radius of curvature. 
     In still another exemplary aspect of the present disclosure, a lock for a ground engaging tool may include a body portion. The body portion may include a first section including a first diameter. The body portion may also include a second section, which may include a second diameter smaller than the first diameter. The lock may also include a neck portion, which may include a third diameter smaller than the second diameter, and extend from the second section. The lock may also include a head portion, which may extend from the neck portion. The head portion may include a surface facing the body portion. In addition, the lock may include a biasing component surrounding the second section of the body portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a bucket edge of a bucket having a ground engaging tool attached thereto according to one exemplary embodiment of the present disclosure; 
         FIG. 2  is a cross-sectional side view of the bucket edge and tool of  FIG. 1 ; 
         FIG. 3  is a bottom view of the tool of  FIG. 1 ; 
         FIG. 4  is a cross-sectional side view of the tool of  FIG. 1 ; 
         FIG. 5  is a cutaway perspective view of the tool of  FIG. 1 ; 
         FIG. 6  is a cross-sectional rear view of the tool of  FIG. 1 ; 
         FIGS. 7A, 7B, and 7C  are cross-sectional top views of a ground engaging tool assembly according to one exemplary embodiment of the present disclosure in various states of assembly; 
         FIGS. 8A, 8B, and 8C  are cross-sectional rear views of a ground engaging tool and a lock of the ground engaging tool assembly of  FIGS. 7A, 7B, and 7C  in the various states of assembly of  FIGS. 7A, 7B, and 7C , respectively; 
         FIG. 9  is a perspective view of a lock of the ground engaging tool assembly of  FIGS. 7A, 7B, and 7C  according to one exemplary embodiment of the present disclosure; 
         FIG. 10  is a top view of the lock of  FIG. 9 ; 
         FIG. 11  is a front view of the lock of  FIG. 9 ; 
         FIG. 12  is a bottom view of the lock of  FIG. 9 ; 
         FIG. 13  is a side view of the lock of  FIG. 9 ; 
         FIG. 14  is a cross-sectional side view of the lock of  FIG. 9 ; 
         FIG. 15  is a perspective view of a lock for a ground engaging tool assembly according to another exemplary embodiment of the present disclosure; 
         FIG. 16  is a top view of the lock of  FIG. 15 ; 
         FIG. 17  is a front view of the lock of  FIG. 15 ; 
         FIG. 18  is a bottom view of the lock of  FIG. 15 ; 
         FIG. 19  is a side view of the lock of  FIG. 15 ; and 
         FIG. 20  is a cross-sectional side view of the lock of  FIG. 15 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a bucket edge  10  of a bucket of an earth-working machine, which may be used for excavating or moving work material in a known manner. The bucket may include a variety of ground engaging tool assemblies. For example, the bucket may include a shroud assembly  20 , as a ground engaging tool assembly. Shroud assembly  20  may include a shroud  30 , which may be configured to be removably attached to bucket edge  10 . Shroud  30  may endure the majority of the impact and abrasion caused by engagement with work material, and wear down more quickly and break more frequently than the bucket. Consequently, multiple shrouds  30  may be attached to bucket edge  10 , worn down, and replaced before the bucket needs to be replaced. As described below with respect to  FIGS. 7A, 7B, 7C, 8A, 8B, and 8C , shroud assembly  20  may also include a lock  40  and a compressible component  50  to secure shroud  30  to bucket edge  10 . While various embodiments of the present disclosure will be described in connection with a particular ground engaging tool (e.g., shroud  30 ), it should be understood that the present disclosure may be applied to, or used in connection with, any other type of ground engaging tools or components. Further, it should be understood that one or more features described in connection with one embodiment can be implemented in any of the other disclosed embodiments unless otherwise specifically noted. 
     Referring to  FIGS. 1-6 , shroud  30  may include an engagement end  60  and a mounting end  70  opposite engagement end  60  along a longitudinal axis  80  of shroud  30  (referring to  FIGS. 2-4 ). Engagement end  60  may endure the majority of the impact and abrasion caused by engagement with work material, and may wear down more quickly than mounting end  70 . Engagement end  60  may thus define one or more wear indicators  90  to facilitate timely replacement of shroud  30 . For example, as best shown in  FIGS. 1, 4, and 5 , wear indicators  90  may include blind holes in engagement end  60 , which do not break through a bottom surface  100  of engagement end  60  until bottom surface  100  has worn down enough to expose wear indicators  90  and thereby provide a wear indication. In some embodiments, wear indicators  90  may be full-life wear indicators. In other embodiments, wear indicators  90  may be half-life indicators or other amount-of-life-indicators, or a combination of different amount-of-life-indicators. Referring to  FIG. 4 , it is contemplated that the amount-of-life indicated by wear indicators  90  may be adjusted by adjusting a depth  110  of wear indicators  90  and/or a distance  120  between wear indicators  90  and a front edge  125  of engagement end  60 . For example, the amount of life indicated by wear indicators  90  may be increased by increasing depth  110  and/or distance  120 . Conversely, the amount of life indicated by wear indicators  90  may be decreased by decreasing depth  110  and/or distance  120 . 
     Referring to  FIG. 2 , mounting end  70  may include mounting legs  130 ,  140 , which may define a recess  150  for receiving bucket edge  10 . As shown, legs  130 ,  140  may include opposing mounting surfaces  160 ,  170  (i.e., surfaces that face each other) for stabilizing shroud  30  relative to bucket edge  10 . Referring to  FIGS. 3-6 , leg  140  may define a lock cavity  180  in shroud  30  for receiving lock  40  and compressible component  50 , as discussed below with respect to  FIGS. 7A, 7B, 7C, 8A, 8B, and 8C . 
     Referring to  FIG. 4 , lock cavity  180  may be accessible only through an opening  190  in surface  170 , allowing rear and top surfaces  200 ,  210  to wear down without exposing lock cavity  180  to any work material which could damage and/or inhibit movement of lock  40  and/or compressible component  50 . As best shown in  FIGS. 3 and 5 , opening  190  may be at least partially rectangle-shaped to facilitate insertion of a rectangular compressible component  50  in lock cavity  180 . 
     Referring to  FIGS. 4-6 , leg  140  may also define a flange  220 , which may extend into cavity  180  along longitudinal axis  80 , away from engagement end  60 . Flange  220  may be adjacent surface  170 , and may be engaged by lock  40  to secure shroud  30  to bucket edge  10 , as discussed below with respect to  FIGS. 7A, 7B, 7C, 8A, 8B, and 8C . As best shown in  FIG. 6 , flange  220  may include a flange surface  230 , which may extend generally parallel to surface  170 . Flange  220  may also include a flange surface  240 , which may slope away from flange surface  230 , toward surface  170 , at an angle  250  relative to surface  170 . In addition, flange  220  may include a flange surface  260 , which may slope away from flange surface  240 , toward surface  170 , at an angle  270  relative to surface  170 . Angle  250  may be less than 90 degrees, and angle  270  may be smaller than angle  250 . 
     Referring to  FIGS. 7A and 8A , compressible component  50  and lock  40  may be configured to be positioned in lock cavity  180 . For example, compressible component  50  may be inserted into cavity  180  before shroud  30  is placed on bucket edge  10 . As shown, compressible component  50  may include an elastomeric material  280  (e.g., rubber, foam, or another type of elastomeric material) and an inelastic material  290  (e.g., metal). Elastomeric material  280  may act as a spring, and inelastic material  290  may distribute forces along elastomeric material  280  to ensure reactive forces provided by elastomeric material  280  are directed approximately along longitudinal axis  80 . Alternatively, compressible component  50  may include only elastomeric material  280 , not inelastic material  290 . In yet another alternative, compressible component  50  may include a compressible material other than elastomeric material  280 . For example, compressible component  50  may include one or more coil springs, leaf springs, and/or other types of springs. 
     Lock  40  may be inserted into cavity  180  after shroud  30  is placed on bucket edge  10 . In particular, a head portion  300  and neck portion  310  of lock  40  may be inserted into cavity  180  through a bore  320  and a counterbore  330  of bucket edge  10 . Since other portions of lock  40  may remain in bore  320  and counterbore  330 , cavity  180  (and leg  140 ) may thus be shorter than lock  40 , minimizing the profile of shroud  30  and allowing shroud  30  to more easily penetrate work material. Once a biasing component  340  of lock  40  engages a planar surface  350  of counterbore  330 , lock  40  may be rotated about rotational axis  360  to secure shroud  30  to bucket edge  10 . 
     Referring to  FIGS. 7B and 8B , lock  40  and shroud  30  may be configured such that at least some rotation of lock  40  in cavity  180  about rotational axis  360  in a first direction compresses compressible component  50  and translates lock  40  along rotational axis  360  away from leg  130 . For example, head portion  300  of lock  40  may include a cam surface  370 , which may engage inelastic material  290  to compress elastomeric material  280  as lock  40  is rotated, thereby pulling shroud  30  onto bucket edge  10 . In addition, head portion  300  may include a bottom surface  380 , which may engage and ride up flange surface  260  to translate lock  40  along rotational axis  360  away from leg  130 , as lock  40  is rotated. Such translation may also compress biasing component  340  of lock  40  against planar surface  350  of counterbore  330 , drawing bucket edge  10  closer to leg  140  and preventing work material from entering cavity  180  through bore  320  and counterbore  330 . 
     Referring to  FIGS. 7C and 8C , lock  40  and shroud  30  may also be configured such that further rotation of lock  40  in cavity  180  (i.e., rotation beyond that shown in  FIGS. 7B and 8B ), about rotational axis  360  in the first direction, allows decompression of compressible component  50  and further translates lock  40 , along rotational axis  360 , away from leg  130 . For example, head portion  300  may include a generally planar end surface  390  positioned relative to cam surface  370  such that when end surface  390  contacts inelastic material  290 , it allows decompression of compressible component  50  as lock  40  is rotated. Bottom surface  380  of head portion  300 , however, may continue to ride up flange surface  260  to further translate lock  40 , along rotational axis  360 , away from leg  130 , as lock  40  is rotated. As shown in  FIGS. 7C and 8C , such translation and rotation may be stopped when a cam surface  400  of head portion  300  contacts flange surface  240 , securing lock  40  in a locked position with end surface  390  contacting inelastic material  290  and bottom surface  380  contacting flange surface  260 . Lock  40  and shroud  30  may thus be configured to prevent further rotation of lock  40  in cavity  180  (i.e., beyond that shown in  FIGS. 7C and 8C ), about rotational axis  360  in the first direction, once rotation of lock  40 , in the first direction, has compressed compressible component  50  and then allowed decompression of compressible component  50 . Rotation about rotational axis  360  in a second direction opposite the first direction, however, may still be possible to unlock and remove shroud  30  from bucket edge  10 . Specifically, such rotation may be possible until a portion of cam surface  400  adjacent end surface  390  contacts a surface  680  of flange  220 . This contact may disturb any work material packed between components of shroud assembly  20  and/or bucket edge  10 , easing removal of shroud  30  from bucket edge  10 . 
     As shown in  FIGS. 9-14  and discussed above, lock  40  may include a head portion  300 , a neck portion  310 , and a biasing component  340 . In addition, lock  40  may include a body portion  410 , which may include a plurality of tool interfaces. For example, body portion  410  may include tool interfaces  420 ,  440 , and/or  460 . 
     Referring to  FIGS. 12 and 14 , tool interface  420  may be configured to receive torque to rotate lock  40  about rotational axis  360 . As shown, tool interface  420  may include a generally square-shaped recess extending into body portion  410  from a bottom surface  430  of body portion  410 . Alternatively, tool interface  420  may include other features configured to be engaged by a tool for applying torque to lock  40  about rotational axis  360 . 
     Referring to  FIG. 14 , tool interface  440  may be configured to receive force to translate lock  40  along rotational axis  360 . As shown, tool interface  440  may include a threaded bore extending into body portion  410  from a top surface  450  of tool interface  420 . Alternatively, tool interface  440  may include other features configured to be engaged by a tool for applying force to lock  40  along rotational axis  360 . 
     Referring to  FIGS. 9, 11, 12, and 14 , tool interfaces  460  may also be configured to receive force to translate lock  40  along rotational axis  360 . As shown in  FIG. 14 , each tool interface  460  may be a slot  470  with top and bottom portions  480 ,  490 , and may extend into body portion  410  from a circumferential surface  500  of body portion  410 , adjacent bottom surface  430 . Top portion  480  may extend further into body portion  410  than bottom portion  490 , so that a top surface  510  of bottom portion  490  can be used to pry lock  40  out of cavity  180  along rotational axis  360 . Although lock  40  is illustrated as having two tool interfaces  460 , lock  40  may alternatively have fewer or more than two tool interfaces  460 . It should be understood, however, that altering the number of tool interfaces  460  could impact the usability of lock  40 . In particular, lock  40 , as illustrated, is rotationally symmetric about rotational axis  360 , meaning that it can be rotated a certain amount about rotational axis  360  and still function in exactly the same way. Specifically, lock  40 , as illustrated, is second order rotationally symmetric about rotational axis  360 . This means that lock  40  can be rotated 180 degrees about rotational axis  360  and still function in exactly the same way, allowing it to be inserted into lock cavity  180  in either of two configurations, 180 degrees apart from each other about rotational axis  360 . 
     As shown in  FIGS. 9-11, 13, and 14 , body portion  410  may include a generally cylindrical lower section  520  and a generally cylindrical upper section  530 . Referring to  FIG. 10 , lower section  520  may have a diameter  540 , and upper section  530  may have a diameter  550 , which may be smaller than diameter  540 . In some embodiments and as best shown in  FIG. 14 , lower section  520  may define a groove  560  extending circumferentially around lower section  520 , which may be configured to receive an O-ring  570  to seal lower section  520  against counterbore  330  of bucket edge  10  (referring to  FIGS. 8A, 8B, and 8C ). Alternatively, body portion  410  may be generally frustum-shaped, and may or may not define a groove extending circumferentially around itself. In such embodiments, the smallest diameter of body portion  410  may be equivalent to diameter  550 . 
     Referring to  FIGS. 9, 11, and 13 , neck portion  310  may be generally cylindrical, and may have a diameter  580 , which may be smaller than diameter  550 . Alternatively, neck portion  310  may be generally frustum-shaped. Neck portion  310  may extend from body portion  410  along rotational axis  360 . For example, neck portion  310  may extend from upper section  530 . 
     As best shown in  FIGS. 9, 10, and 13 , head portion  300  may extend from neck portion  310  along rotational axis  360 . As discussed above, head portion  300  may include bottom surface  380 . Bottom surface  380  may be generally planar, and may face body portion  410 . Head portion  300  may also include a top surface  590 , which may be generally planar. Top surface  590  may face away from body portion  410 , and may be approximately parallel to bottom surface  380 . Head portion  300  may also include generally planar end surfaces  390 ,  600 , which may extend from bottom surface  380  to top surface  590 , and which may be approximately perpendicular to surfaces  380 ,  590 . 
     Referring to  FIGS. 9 and 10 , and as discussed above, head portion  300  may include cam surfaces  370 ,  400 , which may extend from bottom surface  380  to top surface  590 , and which may connect end surfaces  390 ,  600 . Cam surfaces  370 ,  400  may be approximately perpendicular to surfaces  380 ,  590 . As shown, radii of the curves of cam surfaces  370 ,  400  may change between end surfaces  390 ,  600 . For example, in some embodiments, a portion of cam surface  370  not adjacent end surface  390  may have a larger radius of curvature than a portion of cam surface  370  adjacent end surface  390 . By minimizing the radius of curvature of cam surface  370  near end surface  390 , the amount of force applied to compressible component  50  by this portion of cam surface  390  may be maximized for a given amount of torque applied to lock  40  to rotate lock  40  about rotational axis  360 . Such maximization of the force may be desirable, since the portion of cam surface  370  adjacent end surface  390  may apply force to compressible component  50  when compressible component  50  has already been partially compressed and is thus exerting a greater reactive force than in its uncompressed state. Like cam surface  370 , in some embodiments, a portion of cam surface  400  not adjacent end surface  600  may have a larger radius of curvature than a portion of cam surface  400  adjacent end surface  600 . Alternatively, one or both of cam surfaces  370 ,  400  may be otherwise shaped to apply different forces to compressible component  50  depending on a spring constant associated with compressible component  50 . 
     As best shown in  FIGS. 9, 11, 13, and 14 , biasing component  340  may surround upper section  530  of body portion  410 . Biasing component  340  may include an elastomeric material  610  (e.g., rubber, foam, or another type of elastomeric material). In addition, biasing component  340  may include a metal material  620 , which may separate material  610  from lower section  520  of body portion  410 . Metal material  620  may reduce friction between biasing component  340  and lower section  520 , allowing lock  40  to rotate more easily about rotational axis  360 . 
     Ground engaging tools and the associated assemblies of the present disclosure are not limited to the exemplary configurations described above. Certain exemplary aspects of the present disclosure may provide various alternative and/or additional configurations of assemblies for removably attaching ground engaging tools to an implement. For example, further modifications to a lock may be possible without impacting the performance of the lock. In one particular example, illustrated in  FIGS. 15-20 , a lock  640  may be similar to lock  40  but differ in certain ways. For example, like lock  40 , lock  640  may include a head portion  650 , a neck portion  660 , and a body portion  670 , which may be identical to head portion  300 , neck portion  310 , and body portion  410 , respectively. Instead of including biasing component  340 , however, lock  640  may include a biasing component  630 . As shown, biasing component  630  may include a metal coned-disc spring, sometimes referred to as a Belleville washer. Alternatively, biasing component  630  may include one or more coil springs, leaf springs, and/or other types of springs, and may include another type of material (e.g., plastic). In any case, biasing component  630  may function similarly to biasing component  340 , but may be more or less desirable in certain applications. 
     INDUSTRIAL APPLICABILITY 
     The disclosed ground engaging tool assemblies may be applicable to various earth-working machines, such as, for example, excavators, loaders, hydraulic mining shovels, cable shovels, bucket wheels, bulldozers, and draglines. When installed, ground engaging tools of the disclosed ground engaging tool assemblies may protect various implements associated with the earth-working machines against wear in the areas where the most damaging abrasions and impacts occur and, thereby, prolong the useful life of the implements. 
     The disclosed configurations of various components may provide secure and reliable attachment and detachment of ground engaging tools to various earth-working implements, and may have various advantages over previous retainer systems. For example, since lock cavity  180  may be accessible only through opening  190  in surface  170 , rear and top surfaces  200 ,  210  of shroud  30  may wear down without exposing lock cavity  180  to any work material which could damage and/or inhibit movement of lock  40  and/or compressible component  50 . Additionally, since lock  40  may be positioned within cavity  180 , bore  320 , and counterbore  330 , lock  40  may be protected from the abrasion and impacts experienced by shroud  30  during earth-working applications. The operation of the disclosed components will now be described. 
     First, the disclosed compressible component  50  may be inserted into cavity  180  of shroud  30 . Then, after shroud  30  is placed on bucket edge  10 , the disclosed lock  40  may be inserted into cavity  180 . In particular, head portion  300  and neck portion  310  of lock  40  may be inserted into cavity  180  through bore  320  and counterbore  330  of bucket edge  10 . Once biasing component  340  of lock  40  engages planar surface  350  of counterbore  330 , lock  40  may be rotated about rotational axis  360  to secure shroud  30  to bucket edge  10 . Such rotation may cause bottom surface  380  of lock  40  to engage and ride up flange surface  260  to translate lock  40  along rotational axis  360 , compressing biasing component  340  of lock  40  against planar surface  350  of counterbore  330  and drawing bucket edge  10  closer to leg  140  to stabilize shroud  30  and prevent work material from entering cavity  180  through bore  320  and counterbore  330 . The rotation may also cause cam surface  370  of lock  40  to engage inelastic material  290  to compress elastomeric material  280 , thereby pulling shroud  30  onto bucket edge  10 . The rotation may continue until it is stopped by cam surface  400  of lock  40  contacting flange surface  240 , securing lock  40  in a locked position with end surface  390  contacting inelastic material  290  and bottom surface  380  contacting flange surface  260 . In some embodiments, before the rotation is stopped, the rotation may allow decompression of compressible component  50 . Such decompression may prevent lock  40  from leaving the locked position by opposing any loosening of lock  40 . It may, however, still be possible to remove lock  40  (and shroud  30 ) by overcoming this opposition with outside torque applied to lock  40  using tool interface  420 . 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed assemblies. 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.