Patent Publication Number: US-2017350092-A1

Title: Snubber for a dipper door

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to a snubber for a dipper door. More particularly, the present disclosure relates to a snubber for a dipper having a body and a movable door coupled to the body. 
     BACKGROUND 
     Many industrial machines such as rope shovels, diggers, excavators, and the like employ dippers to dig, haul, and transport materials in a given job site. Each of these machines may employ a specific configuration or type of dipper to meet the particular requirements of an application. In the case of a rope shovel, the dipper may typically be configured to have a body and a door that is pivotally coupled to the body so as to allow a swinging movement of the door in relation to the body. If the door is allowed to swing freely it can slam into the body which has a deleterious effect on the working life of the dipper. 
     Numerous designs and mechanisms of linkages have been developed by various manufacturers of such industrial machines to allow the swinging movement of the door for accomplishing an opening and closing of the door with respect to the body of the bucket. 
     U.S. Pat. No. 6,467,202 discloses a dipper door that is pivotally mounted to a dipper. In one embodiment the door is pivotally mounted to the dipper by a pin, and the door is controlled by a linkage actuated by a linear actuator to control the opening and closing of the door. 
     SUMMARY OF THE DISCLOSURE 
     In one aspect of the present disclosure, a snubber for a dipper door is provided. The snubber comprises a five bar linkage including a linear actuator, the linear actuator being configured to provide resistive force to the dipper door via the linkage assembly when the door is closing. 
     In yet another aspect of the present disclosure, a linkage assembly for a door coupled to a body at a pivot mount is provided. The linkage assembly comprising a first link, a second link, and a linear actuator. The first link is pivotally coupled to the body spaced from the pivot mount. The second link is pivotally coupled to the door spaced from the pivot mount, and the first and second links pivotally coupled together at a link pivot. The linear actuator is provided between the pivot mount and the first link. 
     In yet another aspect of the present disclosure, a method of controlling angular movement of a door relative to a body to which the door is coupled at a pivot mount is provided. The method includes pivotally coupling a first link to the body, pivotally coupling a second link to the door, and pivotally coupling the first and second links together. A resistive force is provided to the first link remote from where the first link is pivotally coupled to the body. 
     Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference numbers indicate identical or functionally similar elements. 
         FIG. 1  is a side view of an exemplary machine showing a bucket in which embodiments of the present disclosure can be implemented; 
         FIG. 2  is a perspective view of the bucket showing a linkage assembly, in accordance with embodiments of the present disclosure; 
         FIG. 3  is a side view of the bucket from  FIG. 2  showing the linkage assembly, in accordance with embodiments of the present disclosure; 
         FIG. 4  is a schematic of a 5-bar linkage mechanism formed using components of the linkage assembly from  FIG. 3  in accordance with embodiments of the present disclosure; 
         FIG. 5  is a graph depicting a comparison between resistive forces and torques required by a conventional 3-bar linkage mechanism, a conventional 4-bar linkage mechanism with friction brake therein, and the 5-bar linkage mechanism of the present disclosure for preventing a slamming of the door against the body when the door is positioned at various angles in relation to the body of the bucket, in accordance with an exemplary embodiment of this disclosure; and 
         FIG. 6  is a flowchart depicting a method of controlling angular movement of the door relative to the body, in accordance with an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description of exemplary embodiments of the disclosure herein makes reference to the accompanying drawings and figures, which show the exemplary embodiments by way of illustration only. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical and mechanical changes may be made without departing from the spirit and scope of the disclosure. It will be apparent to a person skilled in the pertinent art that this disclosure can also be employed in a variety of other applications. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. 
     With reference to  FIG. 1 , an exemplary machine  100  is depicted, in which embodiments of the present disclosure may be implemented. As shown, the machine  100  is embodied in the form of an electric rope shovel (ERS) and is shown located on a job site  102 . The machine  100  may be used in a variety of applications including mining, quarrying, road construction, construction site preparation, etc. For example, the ERS shown in  FIG. 1  may be employed for hauling earth materials such as ore, soil, debris, or other naturally occurring deposits from the job site  102 ; and for dumping such earth materials at a designated location for e.g., within a container of a truck, or at another designated location on the job site  102 . 
     Although the exemplary machine  100  is embodied as an ERS in the illustrated embodiment of  FIG. 1 , it will be appreciated that the other types of machines such as, for e.g., but not limited to, diggers, hydraulic excavators, and the like can be optionally used in lieu of the ERS disclosed herein to implement the embodiments of the present disclosure. Moreover, the machine  100  may be a manually operated machine, an autonomous machine, or a machine that is operable in both manual and autonomous mode i.e., a semi-autonomous mode. Therefore, notwithstanding any particular configuration of machine disclosed in this document, it may be noted that embodiments disclosed herein can be similarly applied to various other types and configurations of machines without deviating from the spirit of the present disclosure. 
     Referring to  FIG. 1 , the machine  100  may include a frame  106  for supporting thereon—a drive system  108 , an articulation system  110 , a dipper  112 , and multiple ground engaging members which are shown as tracks  114  in  FIG. 1 . The drive system  108  may include one or more engines (not shown), electric motors for e.g., traction motors (not shown), or both depending on specific requirements of an application. The drive system  108  is configured to produce and transmit output power to the tracks  114  for propelling the machine  100  on the job site  102  and may also be used to transmit output power to the articulation system  110  for performing certain desired functions for e.g., digging, dumping, hauling etc., using the dipper  112  of the machine  100 . 
     In the illustrated embodiment of  FIG. 1 , the articulation system  110  includes a boom  116 , a dipper arm  118 , and a saddle  120 . As shown, the boom  116  is disposed on the frame  106  while the dipper arm  118  is pivotally and slidably coupled to the boom  116  with the help of the saddle  120 . The saddle  120  may allow the dipper arm  118  to be axially displaceable and pivotable along a longitudinal plane AA′ of the machine  100 . Moreover, the dipper  112  is coupled to an end  118   a  of the dipper arm  118 . 
     Additionally, the articulation system  110  may further include a hoist assembly  122  having cables  124  as shown in the illustrated embodiment of  FIG. 1 . In the illustrated embodiment of  FIG. 1 , the cables  124  may be mechanically linked to form endless links, independently or in combination, with one or more pulleys  126  associated with the frame  106 , the boom  116 , the dipper arm  118 , and the dipper  112 . Such configuration of the hoist assembly  122  may be generally representative of one or more block and tackle arrangements known to persons skilled in the art. The hoist assembly  122  may then be operated using drive power from the drive system  108  for co-operatively displacing the dipper arm  118  and the dipper  112  axially and/or pivotally with respect to the boom  116 . 
     In alternative embodiments of this disclosure, it is contemplated that the hoist assembly  122  may be implemented using links, ropes or any other structures or mechanisms known to persons skilled in the art. For example, in an alternative configuration, the hoist assembly  122  may be implemented using hydraulic actuators in conjunction with other types of link structures and mechanisms known to one skilled in the art for performing functions that are consistent with the present disclosure. 
     Further, as shown in the illustrated embodiment of  FIG. 2 , the dipper  112  includes a body  128 , and a door  130  pivotally coupled to the body  128 . The door  130  may include at least one mount arm  136  angularly extending therefrom. Two mount arms  136  are shown in the illustrated embodiment of  FIG. 2 . Each mount arm  136  is pivotally coupled to the body  128  at a first pivot mount  132  as shown in  FIG. 2 , the first pivot mount  132  being disposed on a top side  128   a  of the body  128 . The first pivot mount  132  may therefore facilitate angular movement of the door  130  about the body  128  for accomplishing an opening and closing of the door  130  relative to the body  128  of the dipper  112 . 
     The dipper  112  also includes a snubber in the form of a linkage assembly, shown and generally indicated by numeral  138 . The linkage assembly  138  is disposed between the body  128  of the dipper  112  and the door  130 . The linkage assembly  138  includes a first link  140  and a second link  142 . The first link  140  is pivotally coupled to the body  128  and disposed in a spaced-apart relation to the first pivot mount  132 . As shown in the illustrated embodiments of  FIGS. 2 and 3 , a second pivot mount  146  is provided on the top side  128   a  of the body  128  and disposed in a spaced-apart relation to the first pivot mount  132  for accomplishing a pivotal coupling of the first link  140  to the body  128  of the dipper  112 . 
     The first link  140  and the second link  142  are pivotally connected at a link pivot  144 . As shown in the illustrated embodiment of  FIGS. 2 and 3 , the link pivot  144  may be embodied in the form of a dowel pin  148  received in a pair of apertures (not shown) defined by each of the first and second links  140 ,  142 . In alternative embodiments, the link pivot  144  disclosed herein may include other structures known to persons skilled in the art for establishing a pivotal connection between the first and second links  140 ,  142 . 
     An end  142   a  of the second link  142  is pivotally coupled to the door  130  at a third pivot mount  150  as shown in  FIGS. 2 and 3 , the third pivot mount  150  being disposed on a top side  136   a  of the mount arm  136 . The third pivot mount  150  may therefore facilitate angular movement of the second link  142  about the door  130  for accomplishing an opening and closing of the door  130  relative to the body  128  of the dipper  112 . A pair of third pivot mounts  150  are depicted in the illustrated embodiment of  FIG. 2  to correspond with the pair of mount arms  136  and the pair of linkage assemblies  138 . 
     Each linkage assembly  138  further includes a linear actuator  152  disposed between the first pivot mount  132  and the first link  140 . In one embodiment the linear actuator  152  extends between the first pivot mount  132  and the first link  140  at the link pivot  144 . In other embodiments only one linkage assembly  138  may be provided. In a further embodiment the linkage assembly  138  may be provided centrally between the pivot mounts  132 . 
     In the illustrated embodiment of  FIGS. 2 and 3 , the linear actuator  152  is embodied in the form a hydraulic cylinder having a head end and a rod end. However, in alternative embodiments, the linear actuator  152  may be embodied in the form of other structures known to persons skilled in the art, wherein such other structures are configured to perform functions consistent with embodiments of the present disclosure. Some examples of such structures could include, but is not limited to, a leadscrew or ball screw. 
     It is hereby envisioned that the door  130  should be held closed while the dipper  112  is being loaded and also while the load in the dipper  112  is swung to a deposit point. At that point, the door  130  should be opened to allow the contents of the dipper  112  to fall out. As such, it may be noted here that while loading, hauling and transporting the load, the door  130  and the body  128  of the dipper  112  are configured to co-operatively prevent the contents in the dipper  112  from falling out of the dipper  112 . 
     The linear actuator  152  of the linkage assembly  138  is configured to operatively resist an angular movement of the door  130  relative to the body  128  vis-à-vis the first and second links  140 ,  142 . As shown in the schematic representation of the linkage assembly  138  in  FIG. 4 , the first link  140  is pivotally coupled to the second pivot mount  146 , the second link  142  is pivotally coupled to the first link  140  with the help of the link pivot  144  while the end  142   a  of the second link  142  is pivotally coupled to the third pivot mount  150 . Also, the linear actuator  152  is pivotally coupled to the first pivot mount  132  and the first link  140  at the link pivot  144 . 
     In embodiments disclosed herein, it is envisioned that the first link  140  has a length L which is a multiple of a distance D by which the first link&#39;s pivotal coupling to the body  128  i.e., the second pivot mount  146  is spaced from the first pivot mount  132 , said multiple being in the range of about 0.5 to 1.5. In an example, length L may be 0.7 times the distance D i.e., L=0.7*D. It is envisioned that the length L, being maintained as a multiple of the distance D, also allows control of the angle θ between the linear actuator  152  and the first link  140  while the linear actuator  152  is connected to the first link  140  at the link pivot  144 . The length L may therefore, be selected to provide maximum mechanical advantage to the linear actuator  152  for providing resistive force to the first link  140  as angle θ approaches 90 degrees corresponding to the door  130  approaching a closing position with respect to the body  128 . 
     Moreover, in a further embodiment of this disclosure, it may be additionally or optionally contemplated to shape the second link  142  in a way such that the second link  142  provides a clearance between the second link  142  and the linear actuator  152 . As shown in the illustrated embodiments of  FIGS. 2 and 3 , the second link  142  may be formed to exhibit an arcuate shape as shown in  FIGS. 2 and 3  so that the second link  142  is configured to provide clearance between the second link  142  and the linear actuator  152 . The clearance disclosed herein may aid in preventing an interference between the second link  142  and the co-located linear actuator  152  during an operation of the linkage assembly  138  and hence, facilitate an unobstructed movement of the second link  142  in relation to the linear actuator  152 . 
     Referring again to  FIG. 3 , it is hereby envisioned that the first link  140 , the second link  142 , the door  130 , the body  128  and the linear actuator  152  define a 5-bar linkage mechanism. Specifically, as shown in the schematic of  FIG. 4 , the first link  140 , the second link  142 , the mount arm  136  of the door  130  and the linear actuator  152  together with the first pivot mount  132 , the second pivot mount  146 , the third pivot mount  150 , and the link pivot  144  define a 5-bar linkage mechanism. Hence, for the purposes of this disclosure, it may be noted that the linkage assembly  138  disclosed herein is representative of a 5-bar linkage mechanism. 
     As disclosed earlier herein, an angular motion of the door  130 , the second link  142 , and the first link  140  relative to the second pivot mount  146  may be restricted by the linear actuator  152  while the door  130  is closing in on the body  128  of the dipper  112 . In an embodiment herein, the linear actuator  152  is configured to provide resistive force when a closing angle α between the door and the body is preferably in the range of about 0 to 30 degrees. It will be appreciated by those skilled in the art that the snubber disclosed herein is beneficially configured to provide the resistive force to the door  130  as the door  130  is nearing the body  128  of the dipper  112  to prevent or at least reduce slamming of the door and such resistive force from the snubber may be easily facilitated by providing the first and second links  140 ,  142  and by virtue of the first and second links  140 ,  142  being able to pivot about the link pivot  144 . 
     Moreover, in embodiments disclosed herein, it is envisioned that when the door  130  is in a closed position, an angle θ between the linear actuator  152  and the first link  140  is in the range of about 60 to 90 degrees depending on a configuration of the given linkage assembly  138 . For example, in one exemplary configuration of the linkage assembly  138 , the angle θ between the linear actuator  152  and the first link  140  may be 70 degrees when the door  130  is in the closed position. In another exemplary configuration of the linkage assembly  138 , the angle θ between the linear actuator  152  and the first link  140  may be 80 degrees when the door  130  is in the closed position. In a preferred embodiment, the linear actuator  152  would be configured in a substantially perpendicular position (i.e., approx. or equal to 90 degrees) with respect to the first link  140  when the door  130  is in a closed position. 
     Referring to  FIG. 5 , a graph  500  depicting a comparison between resistive forces and torques typically required by a conventional 3-bar linkage mechanism (not shown), a conventional 4-bar linkage mechanism with a friction brake (not shown), and the 5-bar linkage mechanism of the present disclosure (i.e., the linkage assembly  138  disclosed herein) for preventing a slamming of the door  130  against the body  128  when the door  130  is positioned at various angles in relation to the body  128  of the dipper  112 , in accordance with an exemplary embodiment of this disclosure. 
     It may be seen that an amount of resistive force needed with use of the present linkage assembly  138  is significantly lower than the resistive force needed with use of the conventional 3-bar linkage mechanism when the door is positioned at relatively small angles α with respect to the body  128  of the dipper  112 , wherein such small angles α 0  lie in the range of 0 to 30 degrees as shown in  FIG. 5  and disclosed in a preferred embodiment earlier herein. Such lesser force requirements associated with the 5-bar linkage mechanism i.e., the linkage assembly  138  may help in prolonging a service life of components in the linkage assembly  138 , and more specifically, help prolong a service life of the linear actuator  152  disclosed herein. 
     Various embodiments disclosed herein are to be taken in the illustrative and explanatory sense, and should in no way be construed as limiting of the present disclosure. All numerical terms, such as, but not limited to, “first”, “second”, “third”, or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader&#39;s understanding of the various embodiments, variations, components, and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any embodiment, variation, component and/or modification relative to, or over, another embodiment, variation, component and/or modification. 
     It is to be understood that individual features shown or described for one embodiment may be combined with individual features shown or described for another embodiment. The above described implementation does not in any way limit the scope of the present disclosure. Therefore, it is to be understood although some features are shown or described to illustrate the use of the present disclosure in the context of functional segments, such features may be omitted from the scope of the present disclosure without departing from the spirit of the present disclosure as defined in the appended claims. 
     INDUSTRIAL APPLICABILITY 
       FIG. 6  is a flowchart illustrating a method  600  for controlling an angular movement of the door  130  relative to the body  128  while the door  130  remains coupled to the body  128  at the first pivot mount  132 . At step  602 , the method  600  includes pivotally coupling the first link  140  to the body  128 . At step  604 , the method  600  further includes pivotally coupling the second link  142  to the door  130 . 
     At step  606 , the method  600  further includes pivotally coupling the first and second links  140 ,  142  together at the link pivot  144 . At step  608 , the method further includes providing resistive force to the first link  140  remote from where the first link  140  is pivotally coupled to the body  128 . As disclosed earlier herein, each of the second pivot mount  146  and the link pivot  144  are spaced apart from the first pivot mount  132  at which the first link  140  is pivotally coupled to the body  128 . 
     As disclosed in embodiments herein, the linear actuator  152  is configured to offer resistive force to a closing movement of the door when a closing angle α between the door  130  and the body  128  is in the range of about 0 to 30 degrees. Moreover, such resistive force is provided by the linear actuator  152  when the snubber is substantially perpendicularly to the first link. In a preferred embodiment, the linear actuator  152  would be configured to remain in a substantially perpendicular position (i.e., approx. or equal to 90 degrees) with respect to the first link  140  when the door  130  is in a closed position. 
     Embodiments of the present disclosure have applicability for use and implementation in controlling an angular movement of the door  130  relative to the body  128  of the dipper  112 . Although embodiments of the present disclosure are implemented in conjunction with the dipper  112  of the exemplary machine  100  i.e., the ERS, buckets typically used on other types of machines such as, but not limited to, diggers, hydraulic excavators, and the like may be optionally used to implement the embodiments herein. 
     With implementation of embodiments disclosed herein, the angular movement of the door  130  may be controlled using a reduced or minimal amount of force and/or torque from the linear actuator  152 , due at least in part, to the configuration of the first and second links  140 ,  142  present in the linkage assembly  138  disclosed herein. As the linkage assembly  138  is configured to represent a 5-bar linkage mechanism and by virtue of the first and second links  140 ,  142  being pivotally operable about the link pivot  144 , a length of travel i.e., compression executed by the linear actuator  152  when the door  130  is in the range of 30 degrees or lesser with respect to the body  128  beneficially helps the linear actuator  152  to offer resistive force to the door  130  when the door  130  is nearing the body  128  and hence, decelerate a movement of the door  130  as the door  130  is closing in on the body  128 . Therefore, embodiments disclosed herein can beneficially help in preventing the door  130  from slamming against the body  128  of the dipper  112  after a dumping operation is completed or prior to initiation of a digging cycle. 
     While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.