Abstract:
Low-friction, abrasion resistant systems of replaceable bearing surfaces and methods of using the system are disclosed. The system comprises a device having at least one recess, each recess having a groove in an inner wall of the recess; a plurality of replaceable bearing surfaces adapted to be inserted into and removed from the at least one recess without damaging the device; and at least one snap ring adapted to engage the groove in each recess and secure a replaceable bearing surface within the recess.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. Non-Provisional application Ser. No. 14/746,119, filed Jun. 22, 2015, and entitled “LOW-FRICTION, ABRASION RESISTANT REPLACEABLE BEARING SURFACE,” which is a continuation-in-part of U.S. Non-Provisional application Ser. No. 14/018,066, filed Sep. 4, 2013, and entitled “LOW-FRICTION, ABRASION RESISTANT REPLACEABLE BEARING SURFACE,” which claims priority to provisional application U.S. Provisional Application Ser. No. 61/696,738, filed Sep. 4, 2012, and entitled “LOW-FRICTION, ABRASION RESISTANT REPLACEABLE BEARING SURFACE,” all of which are specifically and entirely incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The invention is directed to friction reducing devices. In particular, the invention is directed to low-friction, abrasion resistant replaceable friction reducing bearing surfaces. 
         [0004]    2. Background of the Invention 
         [0005]    Many industries, including but not limited to oil well drilling, machining, mining, quarrying, and transportation, use mechanisms that need to work under high pressure and high temperature conditions. Furthermore, parts of the mechanisms often rub against each other or external surfaces and, therefore, a low friction, abrasion resistant surface in these parts is desired. 
         [0006]    One solution, for example, is a bearing surface comprised of Polycrystalline Diamond Compact (PDC), a synthetic diamond that performs under harsh conditions. PDC is diamond grit that has been fused together under high-pressure, high-temperature conditions in the presence of a catalytic metal. The extreme hardness, wear resistance, and thermal conductivity of diamond make it an ideal material for bearings. Individual diamond crystals cleave quite easily when struck parallel to certain planes (the process used to facet diamond gemstones takes advantage of these relatively weak planes). Diamond sintering overcomes the problem of weak planes in diamond gemstones by bonding a mass of small diamond particles onto a larger, coherent structure. Sintered diamond provides greater toughness and durability than single crystals because the individual crystals in a sintered body are randomly oriented. This prevents cracks from propagating along the weak planes where traditional diamond crystals cleave most easily. Sintered diamonds also provide more uniform wear than a single crystal, while maintaining similar thermal conductivity and hardness properties. All of these factors combine to make sintered diamond the ideal material for many bearing applications. 
         [0007]    However, overtime, PDC bearings do wear out and can become damaged from intensive use. The PDC bearings are usually embedded into the device by welding and, therefore, in order to replace the PDC bearings, the parts must be removed from operation and transported to a specialized facility that is able to remove the worn out PDC bearings and replace them with new bearings. The process is both costly and time consuming. Furthermore, the repeated heating and cooling needed to replace the bearings causes excessive stress on the devices. Additionally, the welded or brazed bearing pads currently used during refurbishment cannot maintain precision tolerances, especially after multiple replacements. Therefore, it is desirable to have a replaceable low-friction, abrasion resistant bearing surface capable of being replace quickly on-site. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention overcomes the problems and disadvantages associated with current strategies and designs and provides new tools and methods of providing replaceable low-friction, abrasion resistant bearing surfaces. 
         [0009]    One embodiment of the invention is directed to a replaceable bearing surface. The replaceable bearing surface comprises an outer housing and a low-friction, abrasion resistant button secured within the outer housing. The outer housing is adapted to be inserted into and removed from a device without damaging the device. 
         [0010]    In the preferred embodiment, the button is comprised of Polycrystalline Diamond Compact (PDC). Preferably, the outer housing is comprised of 41/30 steel. The button is preferably press fit into the outer housing. Preferably, the outer housing has a notched grip portion and the outer housing has a threaded portion. The threaded portion of the outer housing is preferably adapted to mate with a threaded recess in the device. 
         [0011]    In the preferred embodiment, the button is hemispherical. Preferably, the outer surface of the button extends beyond at least one surface of the outer housing. Preferably, when installed, button extends beyond an exterior surface of the device. 
         [0012]    Another embodiment of the invention is directed to a low-friction, abrasion resistant system. The system comprises a device having at least one recess, a plurality of replaceable bearing surfaces adapted to be inserted into and removed from the at least one recess without damaging the device, each replaceable bearing surface comprising an outer housing, and a low-friction, abrasion resistant button secured within the outer housing. 
         [0013]    Preferably, the button is comprised of Polycrystalline Diamond Compact (PDC). In the preferred embodiment, the outer housing is comprised of 41/30 steel. Preferably, the button is press fit into the outer housing. In the preferred embodiment, the outer housing has a notched grip portion and a threaded portion. Preferably, the threaded portion of the outer housing is adapted to mate with a threaded recess in the device. 
         [0014]    Preferably, the button is hemispherical. Preferably, the outer surface of the button extends beyond at least one surface of the outer housing. In the preferred embodiment, when installed, button extends beyond an exterior surface of the device. The device is preferably one of a drill bit, a reamer, a cam shaft, a bearing, or an axle. 
         [0015]    Another embodiment of the invention is directed to a method of installing and removing a replaceable bearing surface without damaging the device. 
         [0016]    Other embodiments and advantages of the invention are set forth in part in the description, which follows, and in part, may be obvious from this description, or may be learned from the practice of the invention. 
     
    
     
       DESCRIPTION OF THE DRAWING 
         [0017]    The invention is described in greater detail by way of example only and with reference to the attached drawing, in which: 
           [0018]      FIG. 1  is an isometric view of an embodiment of the bearing surface of the invention. 
           [0019]      FIG. 2  is a top view of an embodiment of the bearing surface of the invention. 
           [0020]      FIG. 3  is a cut-away view of an embodiment of the bearing surface of the invention. 
           [0021]      FIG. 4  is a side view of an embodiment of the bearing surface installed in a device. 
           [0022]      FIGS. 5A-B  depict a top and cutaway side view of an embodiment of recess in a device adapted to receive bearing surfaces. 
           [0023]      FIGS. 6A-B  depict a top and cutaway side view of an embodiment of a bearing surface placed within the recess depicted in  FIGS. 5A-B .  FIGS. 7A-B  depict a top and cutaway side view of another embodiment of a bearing surface placed within the recess depicted in  FIGS. 5A-B . 
           [0024]      FIGS. 8A-B  depict a top and side view of the embodiment of the bearing surface depicted in  FIGS. 7A-B . 
           [0025]      FIG. 9  depicts a cutaway side view of another embodiment of a bearing surface of the invention. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0026]    As embodied and broadly described herein, the disclosures herein provide detailed embodiments of the invention. However, the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. Therefore, there is no intent that specific structural and functional details should be limiting, but rather the intention is that they provide a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention. 
         [0027]    A problem in the art capable of being solved by the embodiments of the present invention is replacing worn out bearing surfaces quickly and on-site. It has been surprisingly discovered that providing a replaceable low-friction, abrasion and impact resistant bearing surface allows technicians to replace worn out bearing surfaces themselves without transporting the device to a specialty facility. 
         [0028]      FIG. 1  depicts an isometric view of a preferred embodiment of the replaceable bearing surface  100 . Bearing surface  100  is comprised of an outer housing  105  and a slider button  110 . While one slider button  110  is shown, another number of slider buttons can be used, for example, two or four slider buttons can be used. Preferably, the slider button  110  is a PDC, which has a lower coefficient of friction that carbide or hardened steels. The low coefficient of friction reduces drag during use of the device and thus reduces torque, for example, during drilling of lateral well bores. However, other materials, such as aluminum oxide, silicon carbide, or cubic boron nitride can be used. In the preferred embodiment, slider button  110  is semi-spherical, however other shapes (for example, rectangular, triangular, or semi-ovoidal) can be implemented. Additionally, slider button  110  can be a combination of shapes. Slider button  110  is preferably press fit into outer housing  105 . However, slider button  110  can be coupled to outer housing  105 , for example, with bolts, screws, adhesive, other fastening devices, or screwed into outer housing  105 . 
         [0029]    Preferably, outer housing  105  is comprised of 41/30 steel, however other steels or other materials can be used for outer housing  105 . For example, nylon, other metals, plastics, carbon-fiber, or other naturally occurring or manmade materials. As can be seen in  FIG. 2 , outer housing  105  is preferably cylindrical, having an outer diameter of about one inch. However, outer housing  105  can have other dimensions depending on the device into which bearing surface  100  is installed. For example, outer housing  105  can have a diameter of ½ an inch, 2 inches, or 3 inches. Outer housing  105  preferably has a notched portion  115  on the outer diameter, adjacent to slider button  110 . Notched portion  115  is preferably adapted to be griped by a wrench, pliers, or a person&#39;s fingers. Notched portion  115  preferably aids in installing and uninstalling bearing surface  110  by providing a grippable surface. Outer housing  105  can additionally have other gripping surfaces or a smooth surface. For example, outer housing  105  can have raised knurling, a rubberized grip, or other high friction surfaces. 
         [0030]      FIG. 3  depicts a cut-away side view of bearing surface  100 . Outer housing  105  additionally preferably comprises a threaded portion  120 . Threaded portion  120  preferably is able to mate with a threaded socket in the apparatus into which bearing surface  100  is to be installed. In other embodiments, instead of or in addition to treaded portion  120 , outer housing  105  may have a spring biased cam, a friction increasing device, a pin, adhesive, or another fastening device to keep bearing surface  100  from unintentionally coming out of the apparatus. Preferably, the coupling device is capable of maintaining the outer housing  105  within the apparatus during use of the apparatus and under high stress and high heat conditions. 
         [0031]    As shown in  FIG. 4 , bearing surface  100  is couplable with a device or apparatus. In the preferred embodiment the bearing surface  100  is counter sunk into the device so that only a portion of the bearing surface  100  extends beyond the exterior or the device. For example, only the slider button  110  may extend beyond the exterior of the device. The device can be a drill bit, a reamer, a cam shaft, a bearing, an axle, another machine part, or any other device requiring a low-friction surface. Preferably, the device has a recess with threaded sides that mates with threaded portion  120  of outer housing  105 . In embodiments where outer housing  105  has another fixation device, the recess may have other mating devices. Preferably, the bearing surface  100  can be replaced at the location of use of the device with common tools (for example wrenches, pliers, or screw drivers). Preferably, the bearing surface  100  can be replaced without heating and/or cooling the device, thereby reducing the stress on the device caused during the refurbishment techniques used previously. Additionally, the precision tolerances of the devices can be maintained and repeated during replacement of the bearing surface  100 . Since the bearing surface  100  can preferably be replaced on-site, a transportation cost savings is realized by reducing the number of trips to repair centers. Furthermore, redundant inventory can be reduced since the time previously necessary for shipping and repair is eliminated. 
         [0032]      FIGS. 5A-B ,  6 A-B,  7 A-B, and  8 A-B depict embodiments of the bearing surface using a snap ring retention device.  FIG. 5A  is a top view of a recess  550  in a device  555  and  FIG. 5B  is the cutaway side view thereof. Device  555  can be drill bit, a reamer, a cam shaft, a bearing, an axle, another machine part, or any other device requiring a low-friction surface. Preferably, recess  550  has a cylindrical shape with a flared opening  560 . However, recess  550  can have another shape. For example, recess  550  can be semispherical, pyramidal, cubical, or conical. Preferably, a portion of the inner surface of recess  550  is grooved  565 . Preferably, groove  565  extends into the body of device  555 . In a preferred embodiment, the flared opening  560  of recess  550  may extend further into the body of device  555  than the groove  565  extends. However, in other embodiments the flared opening  560  may be smaller or equal in size to groove  565 . Preferably, groove  565  is positioned within the outer third of recess  565 . However, groove  565  can have another positioning. 
         [0033]      FIG. 6A  is a top view of recess  550  with bearing surface  600  placed therein and  FIG. 6B  is a cutaway side view thereof. Bearing surface  600  may be a PDC, an impact resistant steel, or another material with a low coefficient of friction. Preferably, the coefficient of friction of bearing surface  600  is lower than the coefficient of friction of the material of device  555 . Preferably bearing surface  600  is cylindrical in shape with a domed outer surface. However, bearing surface  600  can have another shape, for example spherical, semispherical, cubical, conical, or another shape. Furthermore, bearing surface may have a flat, chamfered, beveled, or other shaped outer surface. Preferably, bearing surface  600  is contained within a collar  670 . Collar  670  can be of the same material as bearing surface  600 , the same material as device  555 , or of another material. Preferably, bearing surface  600  is press fit into collar  670 . However, baring surface  600  and collar  670  can be coupled using a different method, for example, adhesive, welding, a threaded coupling, pins, screws, bolts, or another fastening device. Preferably, the outer diameter of collar  670  is slightly smaller than the inner diameter of recess  550  so that when collar  670  and bearing surface  600  are placed within recess  550  they do not move freely. Preferably, once placed within recess  550 , bearing surface  600  extends beyond the outer surface of device  555 . Preferably, collar  670  extends a portion of the way up bearing surface  650 . Preferably, the height of collar  670  is equal to the height of groove  565  such that when collar  670  and bearing surface  600  are placed within recess  550  the upper surface of collar  670  is adjacent to groove  565 . 
         [0034]    A snap ring  675  is preferably inserted over collar  670  and into groove  565  to retain collar  670  and bearing surface  600  in recess  550 . Snap ring (or retaining ring)  675  is preferably a removable device that can be squeezed into recess  550  and then extend into groove  565  such that a portion of snap ring  675  is within groove  565  and a portion of snap ring  675  extends over collar  670 . In other embodiments, collar  670  can be held into recess  550  by a spring loaded cam, a pin, a screw, adhesive, a clevis, or another fastening device. Additionally recess  550  may have an opening  580  by which snap ring  675  can be squeezed for insertion and removal. In the preferred embodiment, to replace bearing surface  600 , snap ring  675  is removed, the broken or used bearing surface  600  and collar  670  are then removed. A new bearing surface  600  and collar  670  are inserted into recess  550  and snap ring  675  (either the original or a replacement) is inserted into groove  565 . 
         [0035]      FIG. 7A  is a top view of recess  550  with bearing surface  700  placed therein and  FIG. 7B  is a cutaway side view thereof.  FIGS. 8A and 8B  are top and side views of bearing surface  700 . Bearing surface  700  may be a PDC, an impact resistant steel, or another material with a low coefficient of friction. Preferably, the coefficient of friction of bearing surface  700  is lower than the coefficient of friction of the material of device  555 . Preferably, bearing surface  700  is a single unit that is cylindrical in shape with an upper portion  780  has a smaller radius than the lower portion  785 . Preferably, the outer surface of upper portion  780  is domed. However, bearing surface  600  can have another shape, for example spherical, semispherical, cubical, conical, a combination thereof, or another shape. Furthermore, bearing surface may have a flat, chamfered, beveled, or other shaped outer surface. Preferably, there is a transition zone  790  between the upper portion  780  and the lower portion  785 . Preferably, the outer diameter of lower portion  785  is slightly smaller than the inner diameter of recess  550  so that when bearing surface  700  is placed within recess  550  it does not move freely. Preferably, once placed within recess  550 , bearing surface  700  extends beyond the outer surface of device  555 . Preferably, the height of lower portion  785  is equal to the height of groove  565  such that when bearing surface  700  is placed within recess  550  the upper surface of lower portion  785  is adjacent to groove  565 . In a preferred embodiment, upper portion  780  is milled from lower portion  785 . However, upper portion  780  and lower portion  785  can be formed in different methods, for example, 3D printed, molded, etched, lathed, or a different technique. 
         [0036]    A snap ring  775  is preferably inserted over lower portion  785  and into groove  565  to retain bearing surface  700  in recess  550 . Snap ring (or retaining ring)  775  is preferably a removable device that can be squeezed into recess  550  and then extend into groove  565  such that a portion of snap ring  775  is within groove  565  and a portion of snap ring  775  extends over lower portion  785 . In other embodiments, lower portion  785  can be held into recess  550  by a spring loaded cam, a pin, a screw, adhesive, a clevis, or another fastening device. Additionally, recess  550  may have an opening  580  by which snap ring  775  can be squeezed for insertion and removal. In the preferred embodiment, to replace bearing surface  700 , snap ring  775  is removed, the broken or used bearing surface  700  is then removed. A new bearing surface  700  is inserted into recess  550  and snap ring  775  (either the original or a replacement) is inserted into groove  565 . 
         [0037]      FIG. 9  depicts another embodiment of a bearing surface  900  held into recess  950  in device  955  with a cross-pin  992 . Device  955  can be drill bit, a reamer, a cam shaft, a bearing, an axle, another machine part, or any other device requiring a low-friction surface. Preferably, recess  950  has a cylindrical shape with a flared opening  960 . However, recess  950  can have another shape. For example, recess  950  can be semispherical, pyramidal, cubical, or conical. In the preferred embodiment, after bearing surface  900  is placed within recess  950 , cross-pin  992  is threaded through a hole  993  in the side of device  955  that is perpendicular to recess  950 , through a corresponding hole  994  in bearing surface  900 , and into a cavity  991  in the wall of recess  950 . Preferably, cross-pin  992  slides in and out of holes  993  and  994  and is radially sprung so that cross-pin  992  maintains engagement to the holes with friction. Preferably, cross-pin  992  is removed in order to replace bearing surface  900 . In other embodiments, cross-pin  992  may be kept in place with threading, adhesive, or another fixture. 
         [0038]    Additionally, within recess  950  may be placed a Belleville (or conical spring) washer  995  to help absorb the impacts experienced by bearing surface  900 . While a Belleville washer is shown, other impact absorbing devices may be used. For example, springs, fabrics, foams, or another deformable medium. Preferably washer  995  is placed within recess  950  prior to baring surface  900  being inserted. Additionally, guards  996  and  997  may be placed within recess  950  prior to insertion of bearing surface  900 . Preferably guard  996  is position in the bottom of recess  950  and guard  997  is positioned around the interior surface of recess  950 . Preferably, guards  996  and  997  protect device  955  from wear during use and replacement of bearing surface  900 . Preferably guards  996  and  997  are metal, however they can be made of another material, such as fabric, plastic, or a combination thereof. 
         [0039]    Other embodiments and uses of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. All references cited herein, including all publications, U.S. and foreign patents and patent applications, are specifically and entirely incorporated by reference. It is intended that the specification and examples be considered exemplary only with the true scope and spirit of the invention indicated by the following claims. Furthermore, the term “comprising of” includes the terms “consisting of” and “consisting essentially of.”