Abstract:
A thrust ring is provided that includes: an annularly shaped body defining an interior hole having a diameter; an annularly shaped insert defining an exterior diameter sized similarly to the interior hole diameter; a top surface located on the body, the top surface located adjacent to the interior hole; and an insert surface defined by the insert, the insert surface being annularly shaped; and an interior chamfered surface on the insert intersecting the insert surface. A method of making a thrust ring is provided. The method includes: forming an insert pocket, the insert pocket having an interior diameter in an annular body; forming an annular insert to have an outer diameter slightly larger than the interior diameter of the insert pocket; cooling the insert; and pressing the insert into the insert pocket.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates generally to a thrust ring for a hydraulic hammer. More particularly, the present disclosure relates to manufacturing and/or refurbishing a thrust ring. 
       BACKGROUND 
       [0002]    Hydraulic impact hammers are heavy equipment used in mining, construction, demolition, roadwork, quarrying, and similar applications. These hammers are used to break up concrete, rock, ore, and the like. They are also sometimes used to remove surface portions from an underlying substrate. 
         [0003]    Hydraulic impact hammers generally comprise a housing having a central cylinder. A piston is contained within the cylinder. The top end of the cylinder communicates with or forms part of a gas chamber. The bottom end of the cylinder communicates with a bore in a tool holder which is connected to the housing. The tool holder contains a tool, such as a chisel point, which will strike an object the tool is contacting such as concrete, rock, ore or whatever is being worked by the hammer. The hydraulic fluid forces the piston up compressing the gas in the gas chamber. When the piston reaches a certain height, the hydraulic fluid is allowed to exit the portion of the cylinder below a piston seal and the piston is brought down forcefully to strike the tool. The tool is thus sharply hammered and, in turn, impacts upon the object desired to be impacted. The piston reciprocates rapidly resulting in numerous forceful blows against the tool. 
         [0004]    One feature developed to compensate for the difficult environment described and the intrusion of particles into the lower end of the hammer is the use of a thrust ring. The tool holder, holding the tool in place at the bottom of the hammer does not bear directly against the tool. Rather, a cylindrical thrust ring is fitted into a recess in the bottom end of the tool holder and surrounds the tool. The tool moves within the thrust ring. Wear occurs between the tool and the tool thrust ring. The operator may periodically check the tool and thrust ring for wear, or at regular intervals, the hammer will be disassembled and overhauled. During overhauls, is typically normal to replace the thrust ring. It can be expensive to repeatedly be replacing the thrust ring, particularly when only portions of the thrust ring exhibit signs of wear. 
         [0005]    One patent, U.S. Pat. No. 6,510,904 describes an input bushing for a heavy-duty hydraulic hammer. This patent describes a polymeric bushing protected by a steel ring below the polymeric bushing to prevent foreign objects from impacting on the polymeric bushing. However, the steel ring insert is designed to protect the polymeric bushing from foreign objects from impacting the polymeric bushing and the ring and bushing are made of different materials, rather than wear from the tool and/or piston. 
         [0006]    Accordingly, it is desirable to provide a method and apparatus that allows for a thrust ring to be refurbished when worn in order to avoid the waste of getting rid of an entire thrust ring when only a portion of the thrust bearing exhibits signs of wear. 
       SUMMARY 
       [0007]    The present disclosure provides a thrust ring that includes: an annularly shaped body defining an interior hole having a diameter; an annularly shaped insert defining an exterior diameter sized similarly to the interior hole diameter; a top surface located on the body, the top surface located adjacent to the interior hole; an insert surface defined by the insert, the insert surface being annularly shaped; and an interior chamfered surface on the insert intersecting the insert surface. 
         [0008]    The present disclosure also describes, an insert for a thrust ring includes: an annularly shaped body defining an interior hole having a longitudinal axis; an insert surface defined by the body and located at one end of the body; an underside surface located at an opposite end of the body than the insert surface, the underside surface being more narrow than the insert surface; a ring shaped portion located in an interior of the insert, the ring shaped portion defines a cross-section of the interior hole taken parallel to the longitudinal axis, and the ring shaped portion defines converging and diverging surfaces; and a chamfered surface located on the insert surface and the chamfered surface encompasses the interior hole. 
         [0009]    The present disclosure also describes, a method of making a thrust ring is provided. The method includes: forming an insert pocket, the insert pocket having an interior diameter in an annular body; forming an annular insert to have an outer diameter slightly larger than the interior diameter of the insert pocket; cooling the insert; and pressing the insert into the insert pocket. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a view illustrating a machine equipped with a hydraulic hammer according to a preferred embodiment of the invention. 
           [0011]      FIG. 2  is an isometric, cross-sectional view of a hydraulic hammer including a thrust ring. 
           [0012]      FIG. 3  is a isometric view of a thrust ring. 
           [0013]      FIG. 4  is a bottom, isometric view of an insert for the thrust ring. 
           [0014]      FIG. 5  is a cross-sectional view of a thrust ring configured to accept an insert and the insert is installed in the thrust ring. 
           [0015]      FIG. 6  is a top view of an insert installed in a thrust ring. 
           [0016]      FIG. 7  is a side view of an insert installed in a thrust ring. 
           [0017]      FIG. 8  is a flowchart illustrating steps for installing an insert in a thrust ring. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. An embodiment in accordance with the present invention provides a machine  10  set upon the ground  12 . The machine  10  includes moving elements  14  which, as shown in  FIG. 1  are tracks  14 . In other embodiments, other moving elements such as wheels or any other suitable moving elements  14  may also be used. 
         [0019]    The machine  10  may include an actuator arm  16 . A hammer  18  such as, for example a hydraulic hammer  18 , is mounted to the end of the arm  16 . The hammer  18  actuates a tool bit  20  which may rapidly move up and down in order to pound and/or chisel the various objects such as rock, concrete, pavement, or other objects desired to be fractured. The machine  10  may be an excavator  10 , as shown, or any other type of machine  10  adaptable to actuating and controlling a hammer  18 . 
         [0020]      FIG. 2  is a partial cross-sectional view of a hammer  18  such as the one illustrated in  FIG. 1 . The hammer  18  includes a hammer housing  26  which houses a piston  28 . The piston  28  may be hydraulically (or otherwise) actuated to strike the tool bit  20  through the thrust ring  22 . The striking of the tool bit  20  by the piston  28  causes the tool bit  20  to move up and down and provides a pounding motion the tool bit  20  imparts upon an object such as a rock, concrete, pavement, or any other substance desired to be pounded. 
         [0021]    The hammer housing  26  may also protect other internal parts to the hammer  18  which are either well known or not relevant to the present disclosure. As result, the other elements  30  will not be discussed further. 
         [0022]    As would be apparent to one of ordinary skill in the art after reviewing this disclosure, the thrust ring  22  receives a tremendous amount of repeated force. As result, over time, the thrust ring  22  may exhibit signs of wear or other undesirable fatigue. From time to time it may be desirable to replace or refurbish the thrust ring  22  so that the hammer  18  will continue to operate properly and efficiently. 
         [0023]      FIG. 3  illustrates a typical thrust ring  22 . The thrust ring  22  includes a body  36  having an upper surface  32 , an external chamfer  33  and an internal chamfer  34  encompassing a through hole  35 . The body  36  may also include an exterior ridge  38 . In some embodiments, the exterior ridge  38  may help to secure the thrust ring  22  in position within a hammer  18 . 
         [0024]    During use, the portions of the thrust ring  22  that experience wear include the upper surface  32  and the internal chamfer  34  located around the through hole  35 . In some embodiments, rather than getting rid of the entire thrust ring  22  when it is worn, the thrust ring  22  may be refurbished. An insert  40  as shown in  FIG. 4  may be prepared for insertion into the thrust ring  22 . 
         [0025]    The insert  40  may be made of the same material as the thrust ring  22 . In some embodiments, the material is steel. 
         [0026]      FIG. 4  illustrates the insert  40  viewed from the bottom. The insert  40  may include a body  40  having a side portion  42  which, in some embodiments, defines the insert  40  to be generally cylindrical. The insert  40  may include an underside surface  44 , a ring shaped portion or ledge surface  46 . The insert  40  may define a through hole  35  defined by the ring shaped portion or ledge  46 . The ledge  46  may define a chamfered surface  47  at the through hole  35 . 
         [0027]      FIG. 5  illustrates a cross-section of a thrust ring  50  configured to receive an insert  40  and the insert  40  located in the thrust ring  50 . In this disclosure, the thrust ring not yet having a receiving hole  52  is referred to by reference character  22  and a thrust ring having a receiving hole is referred to by reference character  50 . In some embodiments, an existing thrust ring  22  (which may originally had been a unitary piece such as that shown in  FIG. 3 ) may be machined or otherwise modified to include an insert receiving socket  52  (sometimes referred to as a pocket  52  or hole  52 ). Forming the insert receiving socket or hole  52  includes removing the chamfered surface  34  and a portion of the upper surface  32  shown in  FIG. 3 . The operation of forming the receiving hole  52  may be done by cutting out the hole  52  as the thrust ring  22  turns on a lathe, by drilling out the hole  52  or enlarging a portion of the through hole  35  or any other suitable way of machining or modifying the thrust ring  22 . 
         [0028]    In some embodiments, the thrust ring  50  may be originally manufactured to include the insert receiving hole  52 . In such instances the body  36  of the thrust ring  50  may have the insert receiving hole  52  manufactured into the body  36  during the original fabrication of the thrust ring  50  rather than forming the insert receiving hole  52  and an existing thrust ring  22  as is done in cases of refurbishment of thrust rings  22  not yet having a socket or hole  52 . 
         [0029]      FIGS. 5 ,  6 , and  7  illustrate an embodiment of a thrust ring  50  including and an insert  40  installed into the thrust ring  50 . The thrust ring  50  has the insert  40  placed in the insert receiving socket, pocket, or hole  52 . The insert  40  has a top surface  48  of the ledge or ring portion  46  where the top surface  48  is substantially contiguous with the upper surface  32  of the body  36 . The chamfered surface  33  is located adjacent to the upper surface  32  of the body  36 . The insert  40  also has a chamfered surface  51  encompassing the through hole  35 . The chamfered surface  51  is similar in dimension and shape to the chamfered surface  34  shown in the embodiment of  FIG. 3 . As shown in  FIGS. 5 through 7 , the thrust ring  50 , may include the exterior ridge  38 . In some embodiments, the thrust ring  50  together with an installed insert  40  has the same or very similar overall dimensions, shape, and size as the thrust ring  22  of  FIG. 3 . 
         [0030]    The body  36  of the thrust ring  50  may also include a side portion  53  of the receiving hole  52  and a bottom or a stop portion  54  of the receiving hole  52  as shown in  FIG. 7 . In some embodiments, the undersurface  44  of the insert  40  may contact a stop surface  54  of the body  36  when the insert  40  is fully inserted into the insert receiving socket or hole  52 . The stop surface  54  may be considered as the bottom of the receiving socket or hole  52 . The stop surface  54  may prevent the insert  40  from being pressed too far into the thrust ring  50 . The sides  53  of the receiving hole  52  can help secure and locate the insert  40  within the receiving hole  52 . The side  53  of the receiving hole  52  and the side surface  42  of the insert  40  may be dimensioned and configured so that when the adapter  40  is fully located in the receiving hole or socket  52 , the side  53  of the receiving hole  52  and the side surface  42  to form a contact region such that the upper surface  32  of the thrust ring  50  and the top surface  48  of the insert  40  insert form a contiguous surface. 
         [0031]    As best shown in  FIGS. 5 and 7 , the interior contours  56  of the insert  40  may define a converging and diverging profile as the through hole  35  is initially wide and then narrows at the ring or ledge portion  46  and then widened out again as the interior contours  56  move along axis A-A. The converging and diverging profile may assist in the function of the thrust ring  50 . 
         [0032]    In some embodiments, the thrust rings  22 ,  50  may include fastener holes  58  which allow the thrust ring  22 ,  50  to be secured within the hammer  18 . 
         [0033]      FIG. 8  illustrates a flow diagram of a process that may be used in manufacturing and/or refurbishing a thrust ring  22 ,  50 .  FIG. 8  is a flow chart and, as such, does not have reference characters referencing specific machine parts. The reference characters used after specific machine parts are recited in the following text describing the steps of  FIG. 8  can be seen in  FIGS. 1-7 . As shown in step  51 , the thrust ring  22 ,  50  may be cleaned using any suitable cleaner and/or solvent used in the art for cleaning materials such as steel. The cleaning step  51  may be useful when refurbishing worn thrust rings  22 ,  50  to remove dirt, grease, grime or any other undesired materials located on the thrust ring  22 ,  50  that may have accumulated during use. In embodiments where the thrust ring  22 ,  50  is being newly manufactured to include the insert pocket  52 , the cleaning of the thrust ring  22 ,  50  may aid in removing any unwanted debris or other materials that may have accumulated on the thrust ring  22 ,  50  during its fabrication. 
         [0034]    At step S 2 , the pocket, socket or insert hole  52  is prepared for receiving the insert  40  in the thrust ring  50 . In embodiments where a worn thrust ring  22  is being refurbished, preparing the pocket  52  for the insert  40  may include machining the pocket  52  in the thrust ring  22 . In embodiments where the thrust ring  50  is being newly manufactured to receive the insert  40 , preparing the pocket  52  for the insert  40  may simply include forming the pocket  52 . In some instances, preparing the pocket  52  for the insert  40  may also include heating the pocket  52  area of the thrust ring  50  or the entire thrust ring  50  in order to expand the thrust ring  50  so it may more easily receive the insert  40 . 
         [0035]    At step S 3 , the insert  40  is prepared for being inserted into the pocket  52 . This preparation may include, but is not limited to, cleaning the insert  40  and performing a machining or other operation on the insert  40  to bring the side surface  42  of the insert  40  to a desired dimension. 
         [0036]    At step S 3 , the insert may be cooled prior to being fit into the thrust ring. In some embodiments, the insert  40  may be cooled to a temperature less than negative 30° F. and, in some embodiments, cooled to a temperature of less than negative 40° F. In some embodiments, the insert  40  is cooled to a temperature warmer than negative 100° F. At step S 5  the insert is pressed into the receiving hole or socket  52  in the thrust ring  50 . As can be appreciated by one of ordinary skill the art after reviewing this disclosure, the insert  40  may be press fit (sometimes referred to as an interference fit) into the thrust ring  50 . Cooling the insert  40  may cause the insert  40  to shrink and thereby allowing the insert  40  to more easily be placed into the thrust ring  50 . Once the thrust ring  50  and insert  40  warm to typical ambient temperatures, the insert  40  will expand to form even a tighter fit within the thrust ring  50 . 
         [0037]    Optionally, and as described above, the thrust ring  50  may be heated in order to expand the insert hole or pocket  52  to more easily allow the insert  40  to be placed with in the thrust ring hole or socket  52 . Once the thrust ring  50  returns to a more typical ambient temperature, the thrust ring  50  may shrink thereby grip the insert  40  more tightly. Optionally, fasteners, threads, an epoxy, adhesive, or any other suitable bonding agent may also be used to attach the insert  40  to the thrust ring  50 . 
         [0038]    In some embodiments, once the insert  40  has been fitted into the thrust ring  50 , the thrust ring  50  and insert  40  combination may be proof loaded at step S 6 . The proof loading step S 6  may include subjecting the insert  40  and thrust ring  50  combination to greater forces that would normally be anticipated to be placed on the thrust ring  50  and insert  40  combination and inspecting and/or measuring the thrust ring  50  and insert  40  for any displacement or other abnormality. Once the thrust ring  50  and insert  40  have successfully been proof loaded and inspected, the thrust ring  50  and insert  40  combination may be used in a hammer  18  as described above. 
         [0039]    In some embodiments, the thrust ring  50  and insert  40  combination may again become worn and be in need of refurbishment. In such an instance, the insert  40  may be removed from the thrust ring  50  and the method set forth in  FIG. 8  and described above may be repeated to place a new insert  40  in the thrust ring  50 . Removal of the insert  40  from the thrust ring  50  may be accomplished by using any suitable means. 
       INDUSTRIAL APPLICABILITY 
       [0040]    The apparatus and methods described herein are useful for providing thrust rings for hydraulic hammers. The thrust ring may be provided to the hydraulic hammer when hydraulic hammer is being manufactured or when the hydraulic hammer is undergoing periodic maintenance. Often during periodic maintenance of a hammer, the thrust ring shows signs of wear and needs to be replaced or refurbished. The method and apparatus described herein will provide a method for refurbishing a thrust ring or a source of new or refurbished thrust rings for hydraulic hammers. 
         [0041]    The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.