Patent Publication Number: US-11660604-B2

Title: Milling machine

Description:
TECHNICAL FIELD 
     The present disclosure relates to a milling machine. More particularly, the present disclosure relates to a scraper door associated with the milling machine. 
     BACKGROUND 
     Milling machines typically include a scraper door and a milling drum disposed within a chamber. After conclusion of a milling operation, a work surface on which the milling operation is performed needs to be cleaned. The scraper door is used to clean the work surface behind the milling drum of the milling machine. Further, the scraper door also assists in retention of material in the chamber which is then conveyed out of the opposite side of the chamber to a conveyor system. 
     The scraper door is typically raised and lowered by one or more hydraulic actuators. When the scraper door is in operation, a weight of the scraper door and the hydraulic actuators may apply a pressure on the work surface. Further, excessive pressure on the work surface may damage the work surface. In some cases, while leaving thin amounts of road unmilled, the heavy weight of the scraper door and the pressure from the hydraulic actuators may cause damage to the work surface, which is not desirable. 
     U.S. Pat. No. 6,923,508 describes a stripping means for milling rolls of a construction machine. The stripping means comprises at least one stripping blade arranged behind the milling roll in traveling direction so as to be adjustable in height, which is able to glide over the surface milled or to be milled by the at least one milling roll, it is provided that the stripping blade covers the maximum milling width, and that a mounting means adjustable in height relative to the stripping blade is arranged for at least one lower stripper portion adapted to the respectively used milling roll or milling rolls, the lower stripper portion being able to be positioned, by means of the mounting means, in a position corresponding to the milling roll within the width of the stripping blade. 
     SUMMARY OF THE DISCLOSURE 
     In an aspect of the present disclosure, a milling machine is provided. The milling machine includes a scraper door. The milling machine also includes a control system adapted to control a movement of the scraper door. The control system includes at least one actuator coupled with the scraper door. An extension of the at least one actuator allows lowering of the scraper door and a retraction of the at least one actuator allows raising of the scraper door. The control system also includes a first valve in fluid communication with the at least one actuator. The first valve is operable in a first position for the extension of the at least one actuator and a second position for the retraction of the at least one actuator. The control system further includes a second valve in fluid communication with the first valve. The second valve is adapted to control an amount of fluid pressure being directed towards the at least one actuator via the first valve. The control system includes a control module communicably coupled with the first valve and the second valve. The control module is configured to receive an input signal for raising the scraper door. The control module is also configured to transmit a first signal for operating the first valve in the second position and a second signal for controlling an amount of opening of the second valve for the retraction of the at least one actuator in order to raise the scraper door. 
     In another aspect of the present disclosure, a milling machine is provided. The milling machine includes a scraper door. The milling machine also includes a control system adapted to control a movement of the scraper door. The control system includes a pair of actuators coupled with the scraper door. An extension of each of the pair of actuators allows lowering of the scraper door and a retraction of each of the pair of actuators allows raising of the scraper door. The control system also includes a first valve in fluid communication with the pair of actuators. The first valve is operable in a first position for the extension of the pair of actuators and a second position for the retraction of the pair of actuators. The control system further includes a second valve in fluid communication with the first valve. The second valve is adapted to control an amount of fluid pressure being directed towards the pair of actuators via the first valve. The control system includes a control module communicably coupled with the first valve and the second valve. The control module is configured to receive an input signal for raising the scraper door. The control module is also configured to transmit a first signal for operating the first valve in the second position and a second signal for controlling an amount of opening of the second valve for the retraction of the pair of actuators in order to raise the scraper door. 
     In yet another aspect of the present disclosure, a control system adapted to control a movement of a scraper door associated with a machine is provided. The control system includes at least one actuator coupled with the scraper door. An extension of the at least one actuator allows lowering of the scraper door and a retraction of the at least one actuator allows raising of the scraper door. The control system also includes a first valve in fluid communication with the at least one actuator. The first valve is operable in a first position for the extension of the at least one actuator and a second position for the retraction of the at least one actuator. The control system further includes a second valve in fluid communication with the first valve. The second valve is adapted to control an amount of fluid pressure being directed towards the at least one actuator via the first valve. The control system includes a control module communicably coupled with the first valve and the second valve. The control module is configured to receive an input signal for raising the scraper door. The control module is also configured to transmit a first signal for operating the first valve in the second position and a second signal for controlling an amount of opening of the second valve for the retraction of the at least one actuator in order to raise the scraper door. 
     Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a milling machine, according to one embodiment of the present disclosure; 
         FIG.  2    illustrates a scraper door associated with the milling machine shown in  FIG.  1   , according to one embodiment of the present disclosure; 
         FIG.  3    is a block diagram illustrating a control system for controlling a movement of the scraper door of  FIG.  2   ; and 
         FIGS.  4  and  5    illustrate a hydraulic section of the control system of  FIG.  2   . 
     
    
    
     DETAILED DESCRIPTION 
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.  FIG.  1    is a perspective view of a milling machine  100 , according to one embodiment of the present disclosure. The milling machine  100  is embodied as a cold planer herein, without limiting the scope of the present disclosure. The milling machine  100  operates on a ground surface  102  for performing a milling operation on the ground surface  102 . The milling machine  100  includes a frame  104  and an engine enclosure  106  attached to the frame  104 . The engine enclosure  106  houses an engine (not shown). The engine is generally an internal combustion engine that provides propulsion power to the milling machine  100  and also powers various components of the milling machine  100 . 
     The milling machine  100  defines a front end  108  and a rear end  110 . A pair of front tracks  112  are defined proximate to the front end  108  of the milling machine  100 . Further, a pair of rear tracks  114  are defined proximate to the rear end  110  of the milling machine  100 . Alternatively, the milling machine  100  may include wheels (not shown) instead of the tracks  112 ,  114 . The milling machine  100  has an operator platform  116 . When the milling machine  100  is embodied as a manual or semi-autonomous machine, an operator of the milling machine  100  may sit or stand at the operator platform  116  to operate the milling machine  100 . The operator platform may include various input devices, such as an input device  118 . The input device  118  is embodied as a user interface that allows the operator or a maintenance/servicing personnel to provide inputs for performing one or more machine tasks. Further, the first input device  110  may also provide various notifications to the operator or personnel to assist in improved handling of the milling machine  100 . 
     The milling machine  100  also includes a rotor chamber  120  defined between the front and rear tracks  112 ,  114 . The rotor chamber  120  is an enclosed space. The rotor chamber  120  is enclosed by a first plate  122  and a second plate (not shown) at either sides of the milling machine  100 . Further, a rotor (not shown) that is rotatably coupled to the frame  104  lies within the rotor chamber  120 . The rotor includes a generally cylindrical member and a number of cutting assemblies disposed on the cylindrical member. A portion of the cutting assemblies contact the ground surface  102  for removing material therefrom. 
     Further, the milling machine  100  includes a conveyor system  124 . The conveyor system  124  may be pivotally connected to the frame  104  and is used to transport material away from the rotor chamber  120  and into a receptacle (not shown). The conveyor system  124  includes one or more conveyors for transportation of material. Further, the milling machine  100  includes a scraper door  126 . The scraper door  126  generally extends between the first plate  122  and the second plate. Further, the scraper door  126  is generally rectangular in shape. A size of the scraper door  126  is based on a size of the rotor. 
     The scraper door  126  is used to clean a portion of the ground surface  102  that is milled by the milling machine  100 . More particularly, the scraper door  126  glides over a milled surface to clean the milled surface from remaining milled-off material. In some examples, the scraper door  126  is arranged in a height-adjustable manner. Further, the milled-off material is collected in the rotor chamber  120  and is carried away from the rotor chamber  120  by the conveyor system  124 . In some examples, the scraper door  126  is embodied as a molded cardboard door. 
     Referring now to  FIG.  2   , the milling machine  100  includes a control system  200  to control a movement of the scraper door  126 . More particularly, the scraper door  126  may be raised or lowered based on an operation of the control system  200 . The control system  200  includes one or more actuators  202 ,  204  coupled with the scraper door  126 . In the illustrated example, the control system  200  includes a pair of actuators  202 ,  204 . The actuators  202 ,  204  are embodied as hydraulic actuators. The actuators  204  includes a cylinder  203  and a rod  205 . Further, a piston (not show) and the rod  205  reciprocates within the cylinder  203 . The actuator  204  includes a cylinder  207  and a rod  209 . Further, a piston (not show) and the rod  209  reciprocates within the cylinder  207  The actuators  202 ,  204  include a head end  206 ,  208  coupled with the frame  104  of the milling machine  100  and a rod end  210 ,  212  coupled with the scraper door  126 . The rod ends  210 ,  212  of the actuators  202 ,  204  are coupled proximate to a lower portion  128  of the scraper door  126 . 
     Further, an extension of the actuators  202 ,  204  allow lowering of the scraper door  126  and a retraction of the actuators  202 ,  204  allow raising of the scraper door  126 . More particularly, in order to lower the scraper door  126  fluid pressure is directed towards the head ends  206 ,  208  of the respective actuators  202 ,  204 . Whereas, in order to raise the scraper door  126  fluid pressure is directed towards the rod ends  210 ,  212  of the respective actuators  202 ,  204 . A fluid, such as a hydraulic fluid, may flow in and out of the actuators  202 ,  204  to facilitate movement of the actuators  202 ,  204 . The fluid is received by the head ends  206 ,  208  or the rod ends  210 ,  212  from a pressurized fluid source  214  associated with the control system  200 , such as an accumulator. Further, the fluid exiting the head ends  206 ,  208  or the rod ends  210 ,  212  is directed towards a tank  216  associated with the control system  200 . Moreover, the actuators  202 ,  204  may include position sensors (not shown) that generate signals indicative of a position of the actuators  202 ,  204 . 
     Further, the control system  200  includes a first valve  218 . The first valve  218  is in fluid communication with the actuators  202 ,  204 . The first valve  218  is in fluid communication with the actuators  202 ,  204  via a fluid line  230 . Further, the first  218  is in fluid communication with the tank  214  via a fluid line  232 . The first valve  218  is operable in a first position for the extension of the actuators  202 ,  204  and a second position for the retraction of the actuators  202 ,  204 . More particularly, when the first valve  218  is in the first position, the first valve  218  is in fluid communication with the head ends  206 ,  208  of the respective actuators  202 ,  204 . Further, when the first valve  218  is in the second position, the first valve  218  is in fluid communication with the rod ends  210 ,  212  of the respective actuators  202 ,  204 . The first valve  218  switches between the first and second positions based on signals received from a control module  220 . The first valve  218  is embodied as a solenoid controlled valve. 
     Further, the control system  200  includes a third valve  222 . The third valve  222  is disposed between the first valve  218  and the rod ends  210 ,  212  of the respective actuators  202 ,  204 . The third valve  222  is in fluid communication with the rod ends  210 ,  212  via a fluid line  234 . Further, the third valve  222  is in fluid communication with the first valve  218  via a fluid line  236 . The third valve  222  is embodied as a float lock valve. When actuated, the third valve  222  allows free flow of fluid therethrough. However, when the third valve  222  is de-actuated, the third valve  222  allows locking of the scraper door  126  in a desired position by restricting fluid flow from the rod ends  210 ,  212  of the respective actuators  202 ,  204 . The third valve  222  includes a check valve such that the third valve  222  restricts any fluid flow from the rod ends  210 ,  212  towards the tank  216  to lock the scraper door  126  in the desired position. 
     Further, the control system  200  includes a second valve  224  in fluid communication with the first valve  218 . The second valve  224  is in fluid communication with the first valve  218  via a fluid line  238 . The second valve  224  is in fluid communication with the pressurized fluid source  214  via a fluid line  240 . The second valve  224  controls an amount of fluid pressure being directed towards the actuators  202 ,  204  via the first valve  218 . The second valve  224  includes a proportional pressure reducing valve. It should be noted that an amount of opening of the second valve  224  is based on an input signal. More particularly, the second valve  224  may open partially or fully based on the input signal. The amount of opening of the second valve  224  is based on a desired fluid pressure to which the head ends  206 ,  208  or the rod ends  210 ,  212  of the respective actuators  202 ,  204  need to be subjected. It should be noted that the input signal is provided by an operator of the milling machine  100 . In some examples, the input device  118  may be used to provide the input signal. The second valve  224  is embodied as a solenoid controlled valve. 
     Further, the control system  200  includes a fourth valve  226  and a fifth valve  228 . The fourth valve  226  generally allows free flow of fluid therethrough, however, when the fourth valve  226  is actuated, the fourth valve  226  checks the flow so that fluid can flow through the fifth valve  228 . The fourth valve  226  includes a check valve and the fifth valve  228  is embodied as a pressure relief valve. The fourth and fifth valves  226 ,  228  are actuated only when the scraper door  126  is to be fully raised. More particularly, when the scraper door  126  is to be fully raised, the fourth and fifth valves  226 ,  228  provide a pressure spike for fully raising the scraper door  126 . 
     When the scraper door  126  is to be raised or lowered, pressurized fluid from the pressurized fluid source  214  flows through the second valve  224 . The pressurized fluid is then directed towards the head ends  206 ,  208  or the rods ends  210 ,  212  via the first valve  218 . The pressurized fluid causes the pistons and the rods  205 ,  209  to move towards the head ends  206 ,  208  or the rods ends  210 ,  212 , based on application requirements. Further, fluid exiting the head ends  206 ,  208  or the rods ends  210 ,  212  flows through the third valve  222  and the first valve  218  to return to the tank  216 . 
     The control system  200  includes the control module  220  communicably coupled with the first valve  218  and the second valve  224 . Further, the control module  220  is also communicably coupled with the third valve  226 . When the scraper door  126  is to be lowered, the operator of the milling machine  100  may use the input device  118  to send an input signal to the control module  220  for initiating the lowering of the scraper door  126 . The control module  220  in turn sends a signal to operate the first valve  218  in the first position. 
     Further, the control module  220  also controls the amount of opening of the second valve  224  based on the input signal. The amount of opening of the second valve  224  is based on a desired fluid pressure to be applied at the head ends  206 ,  208  of the respective actuators  202 ,  204 . The desired fluid pressure may be selected by the operator from a number of pressure values. For example, the operator may select if the head ends  206 ,  208  need be subjected to 10% of a maximum allowable pressure, 20% of the maximum allowable pressure, and so on. Based on the selection made by the operator, the control module  220  controls the amount of opening of the second valve  224  for lowering the scraper door  126 . 
     Further, when the scraper door  126  is to be fully raised, the operator of the milling machine  100  may use the input device  118  to send an input signal to the control module  220  for initiating the raising of the scraper door  126 . The control module  220  in turn sends a signal to operate the first valve  218  in the second position. Further, the control module  220  also controls the amount of opening of the second valve  224  based on the input signal. Moreover, in order to fully raise the scraper door  126 , high fluid pressure is directed towards the rod ends  210 ,  212 . For this purpose, the fourth valve  226  blocks a tank line from the second valve  224 , such that high pressure fluid flows over the fifth valve  228  to provide a spike in pressure. Thus, in such a situation, the fourth valve  226  is checked to restrict any fluid flow therethrough. 
     Further, in some situations, a weight of the scraper door  126  in addition to a force applied by the actuators  202 ,  204  may damage a portion of the ground surface  102 , and more particularly, the recently milled surface. The present disclosure is related to a technique wherein the actuators  202 ,  204  are retracted by a small amount in order to apply a lifting force on the scraper door  126  to reduce the weight acting on the ground surface  102  from the scraper door  126 . For this purpose, the control module  220  controls the first and second valves  218 ,  224  in order to allow retraction of the actuators  202 ,  204 . More particularly, the control module  220  receives the input signal for raising the scraper door  126 . 
     The input signal is provided by the operator using the input device  118 . The input signal is indicative of a desired fluid pressure to be applied at the rod ends  210 ,  212  of the respective actuators  202 ,  204 . The desired fluid pressure may be selected by the operator from a number of pressure values. For example, the operator may select if the rod ends  210 ,  212  need be subjected to 10% of a maximum allowable pressure, 20% of the maximum allowable pressure, and so on. It should be noted that the desired fluid pressure selected by the operator may correspond to a small amount of fluid pressure that is sufficient to lift the scraper door  126  so that the weight of the scraper door  126  acting on the ground surface  102  may decrease. 
     Further, the control module  220  transmits a first signal for operating the first valve  218  in the second position and a second signal for controlling an amount of opening of the second valve  224  for the retraction of the actuators  202 ,  204  in order to raise the scraper door  126 . Further, the second valve  224  opens by an amount such that the desired fluid pressure can be applied at the rod ends  210 ,  212 . It should be noted that the control module  220  controls the amount of opening of the second valve  224  based on the input signal. More particularly, based on the input signal from the operator, the control module  220  may in turn control the amount of opening of the second valve  224  for raising the scraper door  126 . 
     Moreover, as the first valve  218  is switched to the second position, the fluid pressure is directed towards the rod ends  210 ,  212  of the respective actuators  202 ,  204  to allow raising of the scraper door  126 . The fluid pressure causes movement of the piston and the rods  205 ,  209  towards the head ends  206 ,  208  which in turn causes raising of the scraper door  126 . 
     The control module  220  may embody a single microprocessor or multiple microprocessors for receiving signals from various components of the milling machine  100 . Numerous commercially available microprocessors may be configured to perform the functions of the control module  220 . It should be appreciated that the control module  220  may embody a machine microprocessor capable of controlling numerous machine functions. A person of ordinary skill in the art will appreciate that the control module  220  may additionally include other components and may also perform other functions not described herein. 
     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 
     The control system  200  associated with the milling machine  100  described herein provides a simple, effective, and cost-efficient solution for slightly lifting the scraper door  126  in order to reduce the weight acting on milled surfaces by the scraper door  126 . More particularly, the control system  200  includes the valves  218 ,  222 ,  224 ,  226 ,  228  and the control module  220  that controls the valves  218 ,  222 ,  224 ,  226 ,  228  for retraction of the actuators  202 ,  204  to lift the scraper door  126 . 
     The control system  200  described herein eliminates any possibility of damage to milled surfaces due to the weight of the scraper door  126 . The low lifting force applied by the actuators  202 ,  204  reduce the pressure applied by the scraper door  126  on the ground surface  102 . However, the retraction of the actuators  202 ,  204  is not high enough to create a clearance between the scraper door  126  and the ground surface  102 , thus the scraper door  128  still performs the intended cleaning function. 
     The control system  200  makes use of components, such as the control module  220  and the valves  218 ,  222 ,  224 ,  226 ,  228 , that are already present on the milling machine  100  which in turn reduces complexity and costs. The control system  200  may be easily retrofitted on any milling machine  100  with limited software modifications, in turn, providing flexibility and compatibility. 
     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 the disclosure. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof