Abstract:
An improved drive pin retention system for mining chains is disclosed, including several embodiments. The drive pin retention system further decreases the chance that the chain can break due to sheared dowel pins.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/172,835 filed Jun. 9, 2015, and U.S. Provisional Application 62/277,550 filed Jan. 12, 2016, which are incorporated herein by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to an apparatus for securing mining chain links. 
       BACKGROUND OF THE INVENTION 
       [0003]    Cutting chains are frequently found in mining operations, including in continuous longwall miners. These chains have tool bits mounted to them that act as picks to repeatedly break apart the surface being mined as the chain is driven around a sprocket. 
         [0004]    Although these mining chains are well known in the prior art, previously known mining chains are prone to failure due to breakage rather than normal wear. 
         [0005]    One frequent area for failure of the mining chain occurs in the connection between links. The links of a mining chain are connected together by drive pins.  FIG. 1 ,  FIG. 2 , and  FIG. 3  depict commonly found mining chains of the prior art. Newer designs of mining chain links, such as that shown in  FIG. 4  of applicant&#39;s own design, also employ drive pins. Previously known retention systems for the drive pin use dowel pins that can shear or break from lateral force or contact with the mining material. When this occurs, the chain breaks and the miner fails. 
         [0006]    The breakage of the chains results in significant downtime and loss of productivity as the continuous longwall miner can no longer function until the chains are repaired or replaced. We disclose herein a drive pin retention mechanism that does not suffer from the problems of the prior art. 
       SUMMARY OF THE INVENTION 
       [0007]    We disclose herein a new drive pin retention system for use in mining chains and other chains comprising: a drive pin having a pin, with retainer cap and various locking mechanisms for securing the retainer cap to the drive pin. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Further advantages of the invention will become apparent by reference to the detailed description of preferred embodiments when considered in conjunction with the drawings: 
           [0009]      FIG. 1  depicts a portion of a mining chain of the prior art. 
           [0010]      FIG. 2  depicts a cutting link of the mining chain of the prior art. 
           [0011]      FIG. 3  depicts a cutting link of the mining chain of the prior art. 
           [0012]      FIG. 4  depicts a cutting link of a mining chain of applicant&#39;s own design. 
           [0013]      FIG. 5  depicts a perspective view of the presently disclosed drive pin with retention mechanism attached using a rubber sandwich pin. 
           [0014]      FIG. 6A and 6B  depict a diagram of a drive pin and retainer used with a perpendicular rubber sandwich pin. Individually,  FIG. 6A  depicts a drive pin, and  FIG. 6B  depicts a retainer. 
           [0015]      FIG. 7A-7E  depicts a rubber sandwich pin to be used with the drive pin of  FIG. 6 . Individually,  FIG. 7A  depicts a perspective view of the rubber sandwich pin.  FIG. 7B  depicts a side elevational view of  FIG. 7A .  FIG. 7C  depicts a cross section along plane A-A of  FIG. 7A .  FIG. 7D  depicts a side elevational view of the rubber sandwich pin.  FIG. 7E  depicts a cross section along plane B-B of  FIG. 7D . 
           [0016]      FIG. 8  depicts a drive pin and retainer secured with a rubber sandwich pin oriented in line with the drive pin. 
           [0017]      FIG. 9A-9E  depicts a D-shaped drive pin and retainer secured with a steel spring pin. Individually,  FIG. 9A  depicts a D-shaped drive pin and retainer secured with a steel spring pin.  FIG. 9B  depicts a D-shaped drive pin.  FIG. 9C  depicts a retainer.  FIG. 9D  depicts a perspective view of a steel spring pin.  FIG. 9E  depicts a side elevational view of the steel spring pin. 
           [0018]      FIG. 10  depicts a threaded drive pin with retainer secured with a rubber sandwich pin oriented in line with the drive pin. 
           [0019]      FIG. 11  depicts a perspective view of a pivot pin. 
           [0020]      FIG. 12  depicts a perspective view of the presently disclosed chain pin. 
           [0021]      FIG. 13  depicts a perspective view of another embodiment of the presently disclosed mining pin. 
           [0022]      FIG. 14  depicts a perspective view of the presently disclosed mining pin retainer. 
           [0023]      FIG. 15A-D  depicts a perspective view of the one embodiment disclosed mining pin with retainer. Individually,  FIG. 15A  depicts a drive pin retention system.  FIG. 15B  depicts a retainer ring.  FIG. 15C  depicts a plastic seal.  FIG. 15D  depicts a dowel pin. 
           [0024]      FIG. 16A-B  depicts a perspective view of the one embodiment disclosed mining pin with retaining cap and bolt. Individually,  FIG. 16A  depicts a drive pin retention system.  FIG. 16B  depicts a retaining cap. 
           [0025]      FIG. 17A-B  depicts a cross-sectional view of one embodiment of the disclosed mining pin and retaining cap and bolt. Individually,  FIG. 17A  depicts a drive pin retention system.  FIG. 17B  depicts a bolt secured by a nylon insert lock nut, also known as a nyloc nut. 
           [0026]      FIG. 18  depicts a cross-sectional view of one embodiment of the disclosed mining pin and retaining cap with fully threaded bolt. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    The following detailed description is presented to enable any person skilled in the art to make and use the invention. For purposes of explanation, specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that these specific details are not required to practice the invention. Descriptions of specific applications are provided only as representative examples. Various modifications to the preferred embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the invention. The present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest possible scope consistent with the principles and features disclosed herein. 
         [0028]    A common point of failure in mining chains of the prior art is in the retention mechanism that holds the drive pins  840  (also known as pivot pins) in place. The drive pin  840  is a generally cylindrically-shaped pin that passes through the transverse bores  410  of the mining chain links. It has a pin head  842  on one end and a fastener end  844  at the opposite end. 
         [0029]    Often, in the prior art, the drive pin  840  was held in place by a retainer  850  that surrounds the fastener end  844  of the drive pin  840 . A dowel pin was driven through a hole in the retainer  850 , and through the drive pin hole  848  in the side of the drive pin  840 . The dowel pin protruded through the retainer  850 , and could easily shear or break from the lateral force or contact with the mining material. When this occurs, the mining chain would break, and the miner fails. Some prior art roller links had protective rings surrounding the retainer that were intended to contain the dowel pin in its location. However, this protective ring could break off, and because there is no positive retention holding the dowel pin in, it could slide out. 
         [0030]    In the presently disclosed invention, the drive pin has a retainer  850  held on by dowel pins that are substantially flush with the retainer. In one embodiment, such as depicted in  FIGS. 5, 6, 7 and 9 , a rubber sandwich pin  860  is used. The rubber sandwich pin  860 , as shown in  FIG. 7A-E , is constructed of two pieces of elongated metal  864  with a rubber center  862  between them. The rubber center  862  is typically injected into the mold between the elongated metal pieces  864 , causing it to adhere to the two elongated metal pieces  864 . As can be seen from  FIG. 7A  and  FIG. 7B , the elongated metal pieces  864  are angled inwards toward the ends, with a middle section that is narrower. As the rubber sandwich pin  860  is driven into the drive pin hole  848 , it is compressed, and re-expands as it exits the other side of the drive pin  840 . This positive retention prevents the rubber sandwich pin  860  from sliding out of the drive pin hole  848 . 
         [0031]    In another embodiment, as shown in  FIG. 9A-9E , a steel spring pin  870  is used. The steel spring  870  depicted in  FIGS. 9D and 9E  has three prongs and a handle  872 . As the steel spring  870  is pushed into the drive pin hole  848  of the drive pin shown in  FIG. 9B , the outer prongs  874  extend outward as they pass into the interior of the drive pin hole  848 . Because of the spring force of the outer prongs  874  against the retainer  850  shown in  FIG. 9C , the steel spring does not easily come out from the drive pin hole  848 . Once again, this positive retention keeps the steel spring pin from sliding out of the drive pin hole. 
         [0032]    Because this rubber sandwich pin  860  or steel spring pin  870  does not substantially protrude past the retainer  850 , there is a significantly reduced chance that either pin will become damaged resulting in the retainer  850  separating from the drive pin  840 . 
         [0033]    Other potential retainers and dowel pins are shown in  FIGS. 11 to 18 . In another embodiment, a Hendrix pin or threaded steel pin with a castle nut is used. The castle nut can be held in place using a cotter pin. This is an excellent solution for repairs. 
         [0034]    The presently disclosed drive pin retention system can be used with any shaped retainer  850  that fits over the fastener end  844  of the drive pin  840 . In one embodiment as shown in  FIGS. 13 and 14 , a D-shaped retainer is used in applications where the drive pin  840  has at least one flat surface cut into the curved sidewall of the drive pin. In another embodiment, such as that shown in  FIG. 10 , the drive pin  840  can be threaded such that the retainer  850  screws into place. Once the holes in the retainer  850  and the drive pin hole  848  are aligned, a rubber sandwich pin or steel spring pin can be placed into the hole. 
         [0035]      FIG. 15A  shows another embodiment of a drive pin retention system. In this embodiment, the retainer  850  is placed over the fastener end  844  of the drive pin  840  (as numbered similarly to  FIG. 10 ). However, in this embodiment, the retainer  850  has two holes that pass all the way through the sidewalls of the retainer along the diameter of the retainer. The drive pin  840  similarly has a drive pin hole  848  that passes through the drive pin  840 .  FIG. 15D  depicts a dowel pin  880  having two notched sections in the surface of the dowel pin such that the diameter at the notched sections is smaller than the diameter of the rest of the dowel pin  880 . The dowel pin  880  is intended to pass through the retainer  850  and the drive pin  840 .  FIG. 15B  depicts a retainer ring  882  having an interior diameter slightly larger than the diameter of the notched section, but smaller than the diameter at the unnotched section. The retainer ring  882  is able to open up slightly under pressure to accommodate the wider sections of the dowel pin  880 . This is accomplished by having the retainer ring  882  be C-shaped so that it can be forced to open wider. Alternatively, the retainer ring  882  can be made of a flexible material that allows it to open wider.  FIG. 15C  depicts a plastic seal  884  that is used to hold the retainer ring  882  in place in the holes of the drive pin  840 . The plastic seal  884  also helps prevent the steel pieces from weakening as they rub against each other. A plastic seal  884  and retainer ring  882  are used on each side of the drive pin  840  to keep the dowel pin  880  in place. 
         [0036]    As will be appreciated from  FIG. 15A-D , the notched dowel pin  880  is held in place by two retainer rings  882  located in the holes of the drive pin  840 . Each of the two retainer rings  882  acts individually as a lock to keep the dowel pin  880  in place. The double locking mechanism ensures that the dowel pin  880  stays in place, even if one retainer ring  882  fails. 
         [0037]    To operate this drive pin retention system, the retainer  850  is placed over the end of the drive pin  840  such that the holes of the retainer  850  line up with the holes of the drive pin  840 . The dowel pin  880  is then hammered through the first hole of the retainer  850  and to the first hole of drive pin  840  which has a retainer ring  882  against its opening, held in place by the plastic seal  884 . The hammering of the dowel pin  880  causes the retainer ring  882  to open up as the dowel pin  880  is squeezed through. As the hammering continues, the dowel pin  880  will then pass through the second retainer ring  882  causing it to open up. As the leading notch of the dowel pin  880  passes through the second retainer ring  882 , the retainer  850  closes around the leading dowel pin notch. The first retainer ring  882  will then also close around the trailing notch. Thus, each retaining ring  882  will be wrapped tightly in a closed position around the notches of the dowel pin  880 . 
         [0038]      FIG. 16A  shows another embodiment of a drive pin retention system. In this embodiment, the retainer  850  is placed over the fastener end  844  of the drive pin  840  (as numbered similarly to  FIGS. 10 and 15A ). However, in this embodiment, the retainer  850  has two holes that pass all the way through the sidewalls of the retainer  850  along the diameter of the retainer  850  as shown in  FIG. 16B .  FIG. 17A  depicts a bolt  886  which is passed into the interior of the drive pin hole  848  and secured by a nyloc nut  888  as shown in  FIG. 17B . The nylon component of the nyloc nut  888  has a smaller inside diameter than the actual nut, thereby acting to lock the nut in place by squeezing the nylon firmly around the bolt when tightened. Unlike a standard locking washer, the nyloc nut  888  prevents the nut from loosening under vibration as the nylon is tightly wedged into the bolt thread and provides resistance to turning once tightened. 
         [0039]    In other potential embodiments of a drive pin retention system, a socket head style bolt can be used. Alternatively a fully threaded bolt as shown in  FIG. 18  is passed into the interior of the drive pin hole  848  and secured by a nyloc nut  888  to strengthen the retention system and ensure the drive pin  840  does not loosen due to vibration. 
         [0040]    It should be appreciated that the cutting link  400  and the pin retention mechanism does not require a whole new mining chain, but instead can be employed by replacing specific links or the retainer cap. Furthermore, although the invention has been described for use with mining, it can be used in other applications, such as trencher chains. The pin retention system can also be used in any chain application. 
         [0041]    The terms “comprising,” “including,” and “having,” as used in the claims and specification herein, shall be considered as indicating an open group that may include other elements not specified. The terms “a,” “an,” and the singular forms of words shall be taken to include the plural form of the same words, such that the terms mean that one or more of something is provided. The term “one” or “single” may be used to indicate that one and only one of something is intended. Similarly, other specific integer values, such as “two,” may be used when a specific number of things is intended. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention. 
         [0042]    The invention has been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the invention. It will be apparent to one of ordinary skill in the art that methods, devices, device elements, materials, procedures and techniques other than those specifically described herein can be applied to the practice of the invention as broadly disclosed herein without resort to undue experimentation. All art-known functional equivalents of methods, devices, device elements, materials, procedures and techniques described herein are intended to be encompassed by this invention. Whenever a range is disclosed, all subranges and individual values are intended to be encompassed. This invention is not to be limited by the embodiments disclosed, including any shown in the drawings or exemplified in the specification, which are given by way of example and not of limitation. 
         [0043]    While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims. 
         [0044]    All references throughout this application, for example patent documents including issued or granted patents or equivalents, patent application publications, and non-patent literature documents or other source material, are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference, to the extent each reference is at least partially not inconsistent with the disclosure in the present application (for example, a reference that is partially inconsistent is incorporated by reference except for the partially inconsistent portion of the reference).