Patent Application
20160024747
The present disclosure relates to a snubber for a machine, and more specifically to the snubber for an implement of the machine.
Machines such as, rope shovels typically include an implement, such as a dipper, for loading and unloading materials. The dipper may include a door that closes a rear of the dipper to hold the materials that are loaded into the dipper. Further, the door is opened to unload the contents of the dipper at a desired location. The door may be typically held closed by a latch mechanism. The latch mechanism may be released to allow the door to swing open under its own weight and the weight of the contents of the dipper. The door may be re-latched as the door rotates back in preparation for its next loading cycle.
During the swinging movement, the door may tend to hit against walls of the dipper or any other proximal component. Sudden opening and closing of the door may also cause wear to components associated with the door. Typically, dippers may be equipped with a braking device on the door linkage to reduce a swing speed as the door swings towards an open and/or closed position.
Conventional dipper door braking devices may utilize dry friction to provide a braking force. As the door swings open or close by virtue of its own weight, the braking device provides friction thereby reducing the swing speed of the door. However, the braking force provided by the braking device tends to reduce as the braking device wears. To maintain the necessary braking force, the braking devices may be subjected to regular maintenance, resulting in machine downtime.
For reference, U.S. Patent Publication No. 2014/007468 (hereinafter the '468 publication) relates to a dipper assembly for a mining shovel. The dipper assembly includes a dipper body and a dipper door that is pivotably coupled to the dipper body, an arm, a housing coupled to one of the body and the door, and a piston. The arm includes a first end pivotably coupled to the body and a second end pivotably coupled to the door. The movement of the door relative to the body drives the arm to pivot relative to the body. The housing includes an inlet in fluid communication with a fluid source, an outlet, and a cylinder. The cylinder partially defines a pump chamber in fluid communication with the inlet and the outlet. The piston is movable within the cylinder and biased in a first direction. The pivoting movement of the arm causes the piston to move in a second direction opposite to the first direction. The movement of the piston changes a volume of the pump chamber.
In one aspect of the present disclosure, a snubber for a machine is provided. The snubber includes a housing, a shaft and a first member. The housing is configured to be mounted on an implement of the machine. The shaft is rotatably received within the housing and operatively coupled to a movable component of the implement. The first member has a plurality of helical splines and is coupled to the shaft. The snubber also includes a cylinder defining a cavity therein, a piston, a second member and a hydraulic device. The cylinder is at least partly disposed within the housing. The piston is slidably received within the cylinder and divides the cavity of the cylinder into a first chamber and a second chamber. The second member has a plurality of helical splines and is coupled to the piston. The helical splines of the second member are configured to engage with the helical splines of the first member to convert a rotation of the shaft into a linear movement of the piston. The hydraulic device is in fluid communication with the cavity of the cylinder. The hydraulic device is configured to control a flow of a fluid between the first chamber and the second chamber to oppose the rotation of the shaft.
In another aspect of the present disclosure, a dipper system for a machine is provided. The dipper system includes a dipper body, a dipper door and a snubber. The dipper door is coupled to the dipper body and is configured to move between an open position and a closed position. The snubber is disposed on the dipper body. Further, the snubber includes a housing, a shaft and a first member. The housing is configured to be mounted on the dipper system of the machine. The shaft is rotatably received within the housing and operatively coupled to the dipper door. The first member has a plurality of helical splines and is coupled to the shaft. The snubber also includes a cylinder defining a cavity therein, a piston, a second member and a hydraulic device. The cylinder is at least partly disposed within the housing. The piston is slidably received within the cylinder and divides the cavity of the cylinder into a first chamber and a second chamber. The second member has a plurality of helical splines and is coupled to the piston. The helical splines of the second member are configured to engage with the helical splines of the first member to convert a rotation of the shaft into a linear movement of the piston. The hydraulic device is in fluid communication with the cavity of the cylinder. The hydraulic device is configured to control a flow of a fluid between the first chamber and the second chamber to oppose the rotation of the shaft.
In yet another aspect of the present disclosure, a method of damping a movement of a dipper door is provided. The method includes receiving a shaft rotatably within a housing. The shaft is operatively coupled to the dipper door. The method also includes coupling a first member having a plurality of helical splines to the shaft and providing a piston slidably within a cavity of a cylinder. The piston divides the cavity of the cylinder into a first chamber and the second chamber. The method further includes coupling a second member having a plurality of helical splines to the piston and transmitting the movement of the dipper door to the shaft. The method includes engaging the helical splines of the first member with the helical splines of the second member to convert a rotation of the shaft into a linear movement of the piston. The method further includes controlling a flow of a fluid from the first chamber of the cylinder to the second chamber of the cylinder to oppose the rotation of the shaft in a first direction. The method also includes controlling a flow of the fluid from the second chamber of the cylinder to the first chamber of the cylinder to oppose the rotation of the shaft in a second direction that is opposite to the first direction.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. Referring to
The machine 100 includes a frame 102 that is configured to mount and/or support various components of the machine 100. The frame 102 is rotatably supported on a set of ground engaging members, for example, tracks 104 that are configured to propel the machine 100 forward or backward on ground. The tracks 104 may also be configured to turn the machine 100 by varying a speed and/or a direction of each of the tracks 104 relative to each other. Further, the machine 100 may be configured to move between a loading position 106 and an unloading position 108 for receiving and dumping the material respectively as the frame 102 swings relative to the tracks 104.
The machine 100 may also include a boom 114 extending upwardly and outwardly from the frame 102. The machine 100 may also includes a crowd mechanism 116 and a hoist mechanism 120 provided on the boom 114. The crowd mechanism 116 includes a handle 117 that is configured to slidably move with respect to the boom 114. The hoist mechanism 120 may include a winch (not shown), a pulley 122 and a hoist cable 124. The hoist cable 124 is connected to the winch at one end.
Referring now to
Further, an other end of the hoist cable 124 extends over the pulley 122 and is connected to the dipper system 200. Based on a rotation of the winch, the cable retracts or extends relative to the winch. Accordingly, the hoist mechanism 120 is configured to raise or lower the dipper system 200 relative to the frame 102. Moreover, the dipper system 200 may extend or retract relative to the frame 102 based on the sliding movement of the handle 117.
The machine 100 may include a dipper trip mechanism 126 that is coupled to the dipper door 204. The dipper trip mechanism 126 may be configured to operate the dipper door 204. The dipper trip mechanism 126 may include a trip motor 134 and a trip cable 136 extending between the trip motor 134 and the dipper door 204. More specifically, the trip cable 136 may be coupled to a locking mechanism (not shown) of the dipper door 204. The locking mechanism may be configured to selectively lock the dipper door 204 to the dipper body 202. The locking mechanism may be any locking mechanism known in the art, such as a latch bar and lever arrangement, and so on. Based on an operation of the trip motor 134, the trip cable 136 retracts and actuates the locking mechanism. Based on an actuation of the locking mechanism, the dipper door 204 may be unlocked to dump the material at the unloading position 108.
Referring to
The dipper door 204 may be pivotally connected to the dipper body 202 and abuts the rearward edges 214 of the dipper walls 208, 210, 212 to close a bottom portion 222 of the dipper body 202. The dipper door 204 is configured to move between an open position and a closed position. In the illustrated embodiment, the dipper door 204 is configured to pivot about a pin joint 228 to swing between the open position and the closed position. The dipper door 204 in the open position may be rotated in a direction R1 (shown in
The machine 100 includes a snubber 300 that may be configured to dampen a swinging motion of a movable component of an implement. In the illustrated embodiment, the snubber 300 may be configured to dampen a swinging motion of the dipper door 204, as the dipper door 204 swings between the open and closed positions. In the illustrated embodiment, two of the snubbers 300 are coupled to the dipper system 200. Moreover, the snubbers 300 are mounted on opposing ends of the rearward edges 214. Therefore, the snubbers 300 may dampen the swinging motion at respective ends of the dipper door 204. Although two snubbers 300 is shown coupled to the dipper system 200, it may be envisioned to use any number of snubbers that may coupled to the dipper system 200 by suitable linkages.
The snubber 300 may be coupled to the dipper system 200 by a linkage assembly 230. In the illustrated embodiment of
It should be noted that the linkage assembly 230 illustrated is exemplary in nature and hence non-limiting of this disclosure. Therefore it may envisioned to use any other appropriate linkage configurations to transmit an opening/closing movement of the dipper door 204 to a rotation of the shaft 302.
The snubber 300 includes a housing 304 that is configured to be mounted on the dipper system 200. The housing 304 may be mounted on the dipper system by using bolts, welding or other suitable methods known in the art. The shaft 302 is rotatably received within the housing 304 and may be operatively coupled to the dipper door 204 via the linkage assembly 230. In an embodiment, a bearing 232 may be disposed between the housing 304 and the shaft 302. The bearing 232 may enable rotation of the shaft 302 relative to the housing 304. In an example, the bearing 232 may be a roller bearing.
Referring now to
The snubber 300 also includes a cylinder 310 that is at least partly disposed within the housing 304. The cylinder 310 defines a central axis that is substantially parallel to the axis A-A′ of the shaft 302. The cylinder 310 also defines a cavity 312 that is configured to slidably receive a piston 314 therein. The piston 314 is configured to divide the cavity 312 into a first chamber 316 and a second chamber 318. The cylinder 310 further defines a first port 320 that is in fluid communication with the first chamber 316 and a second port 322 that is in fluid communication with the second chamber 318. Volumes V1, V2 of the first and second chambers 316, 318 may depend on a position of the piston 314 with respect to the cylinder 310. The piston 314 may also define an opening 324 to receive the first member 308 therein.
The snubber 300 further includes a second member 326 that is coupled to the piston 314. The second member 326 may be disposed in the housing 304 such that an axis of the second member 326 is substantially parallel to the axis A-A′. Further, the second member 326 includes multiple helical splines 329 that are configured to engage with the helical splines 309 of the first member 308. The second member 326 may be a tubular shaft that has the helical splines 329 disposed on an interior surface thereof. In an embodiment, the second member 326 may be provided on an interior surface 327 of the piston 314. Alternatively, the second member 326 may be integral with the piston 314 and the helical splines 329 may be disposed on the interior surface 327 of the piston 314.
The piston 314 may be positioned in the housing 304 such that the second member 326 may face the first member 308. Moreover, the helical splines 329 of the second member 326 engage with the helical splines 309 of the first member 308 such that a rotational movement of the shaft 302 is converted to a linear movement of the piston 314. Further, as the shaft 302 rotates about the axis A-A′, the piston 314 may also rotate about the axis A-A′ and simultaneously translate along the axis A-A′.
As illustrated in
In an embodiment, the piston 314 may include multiple teeth 330 that are disposed on an outer surface 332 of the piston 314. The teeth 330 may be configured to engage with corresponding teeth 334 provided on an inner surface 336 of the cylinder 310. The teeth 330, 334 may extend to a sufficient length such that at least one or more of the teeth 330, 334 may remain engaged with each other during linear movement of the piston 314. The engagement between the teeth 330, 334 may support rotation and translation of the piston 314 relative to the cylinder 310.
Therefore, as the piston 314 moves in the directions L1, L2 based on the rotational movement of the shaft 302, volumes V1, V2 of the corresponding first chamber and the second chamber 316, 318 may vary. Moreover, a fluid may tend to flow between the first chamber 316 to the second chamber 318 through the respective first and second ports 320, 322 based on changes in the volumes V1 and V2 of the first chamber 316 and the second chamber 318. For example, the volume V1 of the first chamber 316 may decrease as the piston 314 moves in the direction L1 and the fluid may tend to flow from the first chamber 316 to the second chamber 318 through the respective first and second ports 320, 322. The flow of the fluid between the first chamber 316 and the second chamber 318 may be controlled so as to oppose the rotation of the shaft 302 in the first and second directions D1, D2.
Accordingly, the snubber 300 includes a hydraulic device 344 that may be configured to control the flow of fluid between the first chamber 316 and the second chamber 318. The hydraulic device 344 may include a manifold 348. In an embodiment, the manifold may be releasably coupled to the housing 304 of the snubber 300.
The hydraulic device 344 may be in fluid communication with the cavity 312 of the cylinder 310. Therefore, as the volume V1 of the first chamber 316 or the volume V2 of the second chamber 318 decreases, the fluid may flow to the hydraulic device 344. The fluid flow may be controlled so as to increase pressure inside one of the first and second chambers 316, 318. Such increased pressure may provide necessary torque to oppose the rotation of the shaft 302, and thereby dampen the movement of the dipper door 204.
For example, during opening of the door, the shaft 302 may rotate in the first direction D1 causing the piston 314 to move linearly in the direction L1. As such, the volume V1 of the first chamber 316 decreases and the fluid may flow from the first chamber 316 to the hydraulic device 344. The hydraulic device 344 may control the flow of the fluid to the second chamber 318 thereby increasing a pressure inside the first chamber 316. Such increased pressure may exert force on the piston 314 that converts to an opposing torque on the shaft 302. The torque may oppose the rotation of the shaft 302 in the first direction D1. Similarly, during closing of the dipper door 204, the fluid flow from the second chamber 318 to the first chamber 316 may be controlled so as to oppose rotation of the shaft 302 in the second direction D2. Such opposition to the rotation of the shaft 302 may be transmitted to the dipper door 204 through the linkage assembly 230 thereby opposing rotation of the dipper door 204.
Referring to
The first flow control module 502 may be configured to control a flow from the first chamber 316 to the second chamber 318 to oppose the rotation of the shaft 302 in the first direction D1, while the second flow control module 504 is configured to control a flow from the second chamber 318 to the first chamber 316 to oppose the rotation of the shaft 302 in the second direction D2.
The first flow control module 502 may include a first flow control valve 506 and a first check valve 508. The first flow control valve 506 is in fluid communication with the first chamber 316 of the cylinder 316 and is configured to restrict a flow of the fluid therethrough. Therefore, as the fluid flows from the first chamber 316 to the first flow control module 502, the first flow control valve 506 allows only a portion of the fluid to flow therethrough.
The first check valve 508 is in fluid communication with the first flow control valve 506 and is configured to allow a unidirectional flow from the first flow control valve 506 to the second chamber 318. In the illustrated embodiment, the first check valve 508 is configured to allow the flow in a direction from the first flow control valve 506 to the first chamber 316 and restricts flow in an opposite direction thereof.
The first flow control module 502 may also include a first pressure relief valve 510 that may be disposed in parallel to the first flow control valve 506 and the first check valve 508. As shown in
Due to the increase in pressure to the first predetermined threshold, the fluid exerts a force on the piston 314 such that the movement of the piston 314 in the direction L1 is opposed. The force translates to a torque on the shaft 302. The torque is in a direction opposite to the first direction D1 of the shaft 302, and hence the rotational speed of the shaft 302 decreases. The linkage assembly 230 may communicate such decreased speed to the dipper door 204, thereby decreasing the swinging speed of the dipper door 204.
Similarly, when the dipper door 204 is moving in the direction R2, the shaft 302 may rotate in the second direction D2. Accordingly, the piston 314 moves in the direction L2 thereby decreasing the volume V2 of the second chamber 318. Therefore the fluid may tend to flow from the second chamber 318 to the first chamber 316 through the respective second and first ports 322, 320. The second flow control module 504 may be configured to control a flow of fluid from the second chamber 318 to the first chamber 316 thereby increasing the pressure inside the second chamber 318. Such increased pressure may exert force on the piston 314 that converts to an opposing torque on the shaft 302. The torque may oppose the rotation of the shaft 302 in the second direction D2.
The second flow control module 504 may be substantially similar to the first flow control module 502. However, the first flow control module 502 may be operable to control the flow from the first chamber 316 to the second chamber 318 to oppose the rotation of the shaft 302 in the first direction D1, while the second flow control module 504 may be operable to control the flow from the second chamber 318 to the first chamber 316 so as to oppose the rotation of the shaft 302 in the second direction D2.
Accordingly, the second flow control module 504 may include a second flow control valve 512 and a second check valve 514. The second flow control valve 512 is in fluid communication with the second chamber 318 and is configured to restrict a flow of the fluid therethrough. Therefore, as the fluid flows from the second chamber 318 to the second flow control module 504, the second flow control valve 512 allows only a portion of the fluid to flow therethrough.
The second check valve 514 is in fluid communication with the second flow control valve 512 and is configured to allow a unidirectional flow from the second flow control valve 512 to the first chamber 316. In the illustrated embodiment, the second check valve 514 is configured to allow the flow in a direction from the second flow control valve 512 to the second chamber 318 and restricts flow in an opposite direction.
The second flow control module 504 may also include a second pressure relief valve 516 that may be disposed in parallel to the second flow control valve 512 and the second check valve 514. As shown in
It may be apparent to a person ordinarily skilled in the art that the second flow control module 504 may not function when the piston 314 moves in the direction L1. The second check valve 514 may prevent flow of the fluid to the second check valve 514 from the first chamber 316. Further, the second pressure relief valve 516 may not allow flow from the first chamber 316 to the second chamber 318. Similarly, the first flow control module 502 may not function when the piston 314 moves in the direction L2.
In an embodiment, the hydraulic device 344 may include one or more accumulators (not shown) that are configured to maintain the fluid at a predetermined pressure. Each of the accumulators may be in fluid communication with the hydraulic circuit 500, and one of the first and second chambers 316, 318. The accumulator may receive a fluid from the corresponding first and second chambers 316, 318 when a volume of the fluid increases. The accumulator may include a pressurized gas (for example, nitrogen) that may be used to maintain a predetermined pressure therein.
It should be noted that the hydraulic circuit 500 illustrated in
The present disclosure relates to the dipper system 200 including the snubbers 300 and a method 600 of damping a movement of the dipper door 204. At step 602, the method 600 includes receiving the shaft 302 rotatably within the housing 304. The shaft 302 is operatively coupled to the dipper door 204. At step 604, the method 600 includes coupling the first member 308 to the shaft 302. The first member includes multiple splines 309. At step 606, the method 600 includes receiving the piston 314 slidably within the cavity 312 of the cylinder 310. The piston 314 divides the cavity 312 into the first chamber 316 and the second chamber 318.
At step 608, the method 600 includes coupling the second member 326 to the piston 314. The second member 326 includes multiple splines 329. At step 610, the method 600 includes transmitting the movement of the dipper door 204 to the shaft 302. At step 612, the method 600 includes engaging the helical splines 309 of the first member 308 with the helical splines 329 of the second member 326 to convert a rotation of the shaft 302 into a linear movement of the piston 314.
At step 614, the method 600 includes controlling the flow of a fluid from the first chamber 316 to the second chamber 318 to oppose the rotation of the shaft 302 in the first direction D1. At step 616, the method 600 includes controlling the flow of the fluid from the second chamber 318 to the first chamber 316 to oppose the rotation of the shaft 302 in the second direction D2 that is opposite to the first direction D1.
The snubber 300 according to the present disclosure, may be retrofitted onto any rope shovel or other machines having an implement with a movable door. The snubber 300 may reduce the swinging speed of the dipper door 204 by opposing the rotation of the shaft 302 that is operatively coupled to the dipper door 204.
The first and second predetermined thresholds for the first and second pressure relief valves 510, 516 may be selected to provide a desired pressure inside the first chamber 316 or the second chamber 318, and the corresponding torque to the shaft 302. Further, using the helical splines 309, 329 to convert the rotation of the shaft 302 to the linear movement of the piston 314 may enable a simple and robust design of the snubber 300.
Additionally, use of the hydraulic device 344 may minimize mechanical couplings and/or friction that may result in wear. Therefore, the snubber 300 may have reduced maintenance costs. The snubber 300 may also have reduced frequency of maintenance, thereby decreasing machine downtime and associated costs. Moreover, the snubber 300 may have an increased service life and reliability.
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.
File: 14-0737
