Patent Publication Number: US-2016243690-A1

Title: Variable damping system for a power cell of a hydraulic hammer

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to a damping system. More particularly, the present disclosure relates to a variable damping system for a power cell of a hydraulic hammer. 
     BACKGROUND 
     Hydraulic power hammers typically include a power cell enclosed within a housing. Moreover, the hydraulic hammers may employ one or more dampers disposed between the power cell and the housing. For reference, U.S. Pat. No. 5,419,404 relates to a hydraulic impact hammer comprising a protective casing made of two side plates, and provided with attenuation elements for eliminating the noise and vibration caused by the impact hammer. 
     Although the dampers or attenuation elements are provided to attenuate noise and/or vibrations experienced during operation of the hydraulic hammers, the amount of damping accomplished with use of such dampers or attenuation elements is fixed. In many cases, an operator controlling the hydraulic hammer via a control implement may wish to vary this amount of damping depending on how he wishes to feel the responsiveness of the hydraulic hammers in the control implement. Hence, there is a need for a system that provides an operator of a hydraulic hammer with the ability to vary the amount of damping in the hydraulic hammer. 
     SUMMARY OF THE DISCLOSURE 
     In an aspect of the present disclosure, a variable damping system for a power cell of a hydraulic hammer is disclosed. The hydraulic hammer has a housing and a mounting bracket disposed on a top side of the housing. The variable damping system includes an expandable bladder that is positioned between the power cell and an underside of the mounting bracket. The expandable bladder is configured to receive a supply of pressurized fluid and maintain a pre-determined volume of pressurized fluid therein. 
     In another aspect of the present disclosure, a hydraulic hammer includes a housing, a mounting bracket disposed on a top side of the housing, and a power cell disposed within the housing. The hydraulic hammer further includes a variable damping system for damping vibrations during operation of the power cell. The variable damping system includes an expandable bladder that is positioned between the power cell and an underside of the mounting bracket. The expandable bladder is configured to receive a supply of pressurized fluid and maintain a pre-determined volume of pressurized fluid therein. 
     In yet another aspect of the present disclosure, a machine for drilling work surfaces includes a hydraulic hammer, a control implement that is operable to control functions of the hydraulic hammer, and a variable damping system that is configured to damp vibrations from the hydraulic hammer to the control implement in at least one of an underdamped state, a critically damped state, and an overdamped state. 
     The hydraulic hammer has a power cell that is enclosed within a housing. The hydraulic hammer also includes a mounting bracket that is disposed on a top side of the housing. The control implement is coupled to the power cell of the hydraulic hammer. The variable damping system includes an expandable bladder that is positioned between the power cell and an underside of the mounting bracket. The expandable bladder is configured to maintain a pre-determined volume of pressurized fluid therein. The variable damping system further includes a pump that is disposed in fluid communication with the bladder. The pump is configured to supply the pre-determined volume of pressurized fluid to the bladder. 
     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 diagrammatic view of an exemplary machine using a hydraulic hammer in accordance with an embodiment of the present disclosure; 
         FIG. 2  is a schematic view of the hydraulic hammer and a control implement in accordance with an embodiment of the present disclosure; 
         FIG. 3  is an exploded view of the hydraulic hammer in accordance with an embodiment of the present disclosure; and 
         FIG. 4  is an exploded view of the hydraulic hammer in accordance with another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to same or like parts. Moreover, references to various elements described herein are made collectively or individually when there may be more than one element of the same type. However, such references are merely exemplary in nature. It may be noted that any reference to elements in the singular is also to be construed to relate to the plural and vice-versa without limiting the scope of the disclosure to the exact number or type of such elements unless set forth explicitly in the appended claims. 
       FIG. 1  shows a diagrammatic view of an exemplary machine  100 . The machine employs a hydraulic hammer  102  shown in accordance with an embodiment of the present disclosure. The hydraulic hammer  102  includes a pecking tool  104  that is configured to break rocks and penetrate ground surfaces. 
     In the illustrated embodiment of  FIG. 1 , the machine  100  is embodied in the form of a tracked industrial vehicle such as an excavator, wherein the hydraulic hammer  102  is mounted to replace an excavator bucket (not shown) previously associated with the excavator. Consequently, the hydraulic hammer  102  may be beneficially operated by the excavator&#39;s hydraulics. However, it can be optionally contemplated to use other types of machines and carriers to power the hydraulic hammer  102  of the present disclosure. 
     As shown in  FIG. 1 , the machine  100  includes a frame  106 ; one or more linkages  108 ,  109 ; and a mounting bracket  110  that pivotally connects the hydraulic hammer  102  to the linkage  109 . The linkages  108 ,  109  may be articulated relative to the frame  106  in order to change an orientation and/or position of the hydraulic hammer  102  with respect to a ground surface. The machine  100  includes a control implement  112  that may be located within a cab  114 . The control implement  112  may be used by an operator to control functions of the hydraulic hammer  102 . 
     Referring to  FIG. 2 , a schematic view of the hydraulic hammer  102  and the control implement  112  is rendered in accordance with an embodiment of the present disclosure. The hydraulic hammer  102  includes a housing  116  that is configured to enclose a power cell  118  therein. Moreover, the mounting bracket  110  is disposed on a top side  120  of the housing  116 . The power cell  118  is configured to drive the pecking tool  104  of the hydraulic hammer  102  so that the pecking tool  104  may perform functions that are consistent with the present disclosure. The present disclosure relates to a variable damping system  122  that is provided for damping vibrations during operation of the hydraulic hammer  102 . 
     As shown in  FIG. 2 , the variable damping system  122  includes an expandable bladder  124  that is positioned between the power cell  118  and an underside  126  of the mounting bracket  110 . The expandable bladder  124  is configured to maintain a pre-determined volume of pressurized fluid therein. In one embodiment, the pressurized fluid may be air. In another embodiment, the pressurized fluid may be a gas, for e.g., nitrogen. In an alternative embodiment, the pressurized fluid may be a liquid, for e.g., oil having suitable characteristics and/or of a specific grade for the required application. Optionally, the pressurized fluid disclosed herein, may also be a mixture containing air, gases, and/or liquids. For example, in one application, it may be helpful to use a mixture of nitrogen and a specific type of oil as the pressurized fluid. 
     In various embodiments disclosed herein, it may be noted that the exact specifications of the pressurized fluid may vary from one type and/or configuration of hydraulic hammer to another, and/or from one application to another depending on specific requirements of the associated application. Therefore, any type of fluid may be used to form the pressurized fluid disclosed herein without deviating from the scope of the present disclosure. 
     The variable damping system  122  may further include a pump  128 . In an embodiment, the pump  128  may be disposed in fluid communication with the bladder  124 . In another embodiment, an operator may fluidly couple the pump  128  to the bladder  124  when needed. The pump  128  is configured to supply the pre-determined volume of pressurized fluid to the bladder  124 . As the pressurized fluid may include any type of fluid therein, a type of pump employed in the variable damping system  122  is suitably selected to correspond with the type of fluid being used in the bladder  124  of the hydraulic hammer  102 . In an embodiment, the pump  128  may be configured to pressurize liquid phase alone. In another embodiment, the pump  128  may be configured to pressurize gaseous phase alone. In an alternative embodiment, the pump  128  may be of a type that is adapted to pressurize a mixture of liquid phase and gaseous phase. 
     In an embodiment as shown in  FIG. 2 , the variable damping system  122  may, optionally or additionally, include a pressure gauge  130 . This pressure gauge  130  may be disposed between the pump  128  and the bladder  124  to display a pressure of the fluid being supplied to the bladder  124 . Such information may assist the operator in operating the hydraulic hammer  102  with a desired amount of pressurized fluid in the bladder  124 . 
     It is hereby envisioned that the pressurized fluid maintained in the bladder  124  will allow the bladder  124  to damp vibrations from the power cell  118  of the hydraulic hammer  102 . This way, the vibrations from the power cell  118  may be prevented from entering into the control implement  112  (See  FIG. 1 ) that is used by the operator to control functions of the hydraulic hammer  102 . 
     Moreover, the expandable bladder  124  may be beneficially made from an elastomeric material such as Neoprene, Rubber, and other types of elastomers commonly known to one skilled in the art. The expandable nature of the bladder  124  may allow the operator to selectively switch the pump  128  “ON” or “OFF” and vary the amount of pressurized fluid in the bladder  124 . 
     Depending on the amount of pressurized fluid maintained in the bladder  124 , vibrations from the power cell  118  may be underdamped, critically damped, or overdamped. As such, an operator of the machine may pre-determine the amount of pressurized fluid that is to be maintained in the bladder  124  depending on the responsiveness of the hydraulic hammer  102  at the control implement  112  to the operator. For example, if the operator wishes to feel a significantly higher amount of vibrations when operating the control implement  112 , he may choose to fill the bladder  124  with more fluid so as to underdamp the vibrations during operation of the hydraulic hammer  102 . However, if the operator wishes to feel a moderate amount of vibrations at the control implement  112 , he may choose to fill the bladder  124  with lesser fluid for a softer response to the vibrations. This way, the vibrations from the hydraulic hammer  102  may be critically damped or over damped and therefore, little or no vibrations may be experienced by the operator when operating the control implement  112 . 
     In an embodiment as shown in  FIG. 3 , the variable damping system  122  may further include a retainer  132  that is associated with the bladder  124 . The retainer  132  may be configured to retain a form and fit of the expandable bladder  124  within the housing  116  of the hydraulic hammer  102 . As shown, the retainer  132  is in the shape of an annular rim. In an example, the retainer  132  may be made of metal. In other examples, the retainer  132  may be made of other materials such as fibre glass to suit a specific requirement of the application. 
     The retainer  132  includes at least one port  134  that is disposed in fluid communication with the expandable bladder  124 . In the illustrated embodiment, the retainer  132  includes one port  134 . The port  134  may be configured to receive a supply of the pressurized fluid and discharge the pressurized fluid into the bladder  124 . The port  134  may be fluidly coupled to the pump  128  to receive the supply of the pressurized fluid. The port  134  may also be configured to allow a discharge of the pressurized fluid from the bladder  124 . 
     Further, as shown in the illustrated embodiment of  FIG. 3 , the bladder  124  includes a top portion  138  and a bottom portion  140 . The top portion  138  has a first rimmed end  142  that is configured to engage with a top side  144  of the retainer  132  while the bottom portion  140  has a second rimmed end  146  that is configured to engage with a bottom side  148  of the retainer  132 . Each of the top portion  138  and the bottom portion  140  of the bladder  124  is annular in shape to conform to the annular shape of the retainer  132 . In such a case, the retainer  132  may further include at least one vent port  136  to allow a passage of the pressurized fluid received via the port  134  to both the top portion  138  and the bottom portion  140  of the bladder. 
     In another embodiment as shown in  FIG. 4 , the retainer  132  may be configured such that the port  134  is located on an inner surface  150  similar to that shown in the illustrated embodiment of  FIG. 3 . Moreover, as shown in the illustrated embodiment of  FIG. 4 , the top portion  138  of the bladder  124  and the bottom portion  140  of the bladder  124  may be integral with one another so as to impart a unitary construction to the bladder  124 . 
     Various embodiments disclosed herein are to be taken in the illustrative and explanatory sense, and should in no way be construed as unduly limiting of the present disclosure. All directional references (e.g., above, below, upper, lower, top, bottom, vertical, horizontal, inward, outward, radial, upward, downward, left, right, leftward, rightward, clockwise, and counter-clockwise) are only used for identification purposes to aid the reader&#39;s understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Joinder references (e.g., attached, affixed, coupled, engaged, connected, and the like) are to be construed broadly. Moreover, such joinder references do not necessarily infer that two elements are directly connected to each other. 
     Additionally, 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 
     The variable damping system  122  of the present disclosure has applicability in damping vibrations experienced during operation of hydraulic hammers. 
     In an aspect of the present disclosure, the bladder  124  of the present disclosure is configured to maintain varying amounts of pressurized fluid therein so as to accomplish a varying amount of damping i.e., underdamping, overdamping, and critically damping, to the vibrations from the hydraulic damper. This ability to adjust i.e., increase or decrease the amount of damping to the vibrations allows an operator of a machine with improved flexibility to choose the amount of vibrations experienced at the control implement  112 . This way, the control implement  112  may be imparted with an operator-desired amount of vibration that allows for better handling of the control implement  112  by the operator. 
     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.