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CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/267,893, filed Dec. 15, 2015, which is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to heavy machinery equipment, and more particularly to ripper teeth, tooth adapters, and the fasteners for coupling ripper teeth and tooth adapters to heavy machinery equipment shovels. 
     BACKGROUND OF THE INVENTION 
     Heavy machinery equipment is used in mining, excavation, demolition, construction, and similar activities. The parts of heavy machines which are used for digging are exposed to a great amount of wear in operation. For instance, a ground engaging tool has teeth which continually dig, rip, cut, or lift dirt, rock, concrete, metal, or other heavy and rugged materials, which constantly wear against and abrade the surface of the teeth. 
     Heavy machinery parts are expensive and time-consuming to repair or replace, so many pieces of equipment are applied with wear plates or wear structures which can be replaced more quickly. For instance, on a ripper, the tooth may be a durable cover fitted onto the end of the ripper shank, so that when the tooth wears out, the tooth is removed and replaced without the need to repair the entire ripper shank. By removing and replacing only those parts which directly engage with the ground, considerable time and expense can be saved. 
     However, there are many safety issues with current designs of replacement parts. Current designs generally require that a sledgehammer be used to install pins which secure the replacement parts on the ripper shank. The pins are hammered into the parts, and often a tool is placed against the pin and hammered with the sledgehammer. This can lead to serious injury when the tool moves, is broken, or the sledgehammer misses its mark. The safety organizations which regulate workplace safety, such as MSHA and OSHA, disapprove of pins and replacement parts which require sledgehammers for installation. Further, a sledgehammer is also frequently used to remove the pin, by hammering the pin out of the replacement part. Again, this often leads to serious injury. 
     Many manufacturers of such replacement parts also incorporate unique or proprietary features in the parts that make removal and replacement difficult and expensive. Some manufacturers build replacement parts with special slots that will only accommodate their own tools. Others build parts that will only accept their own replacement parts. For instance, on a shovel, a tooth adapter fit on the shovel may be specially formed to only accept a tooth from the same manufacturer that made the adapter. Similarly, the tooth may have a slot or other engagement feature that requires that a proprietary pin be used to couple the tooth to the end of the adapter, because a slot formed between the adapter and the tooth will only accept those pins. Still further, some manufacturers may create coupling pins that require uniquely-shaped keys or tools to install or remove the pins. These fasteners can be difficult or dangerous to remove, risking bodily harm or even death, and generally incurring enormous opportunity costs while the shovel is prevented from operating. An improved fastening device for coupling heavy equipment parts is needed, as is an improved tooth and adapter assembly for heavy equipment. 
     SUMMARY OF THE INVENTION 
     Several hammerless pin assemblies for coupling pieces of heavy equipment include a pin that uses a detent to engage the pin between the pieces of heavy equipment. In one embodiment, a hammerless tooth adapter pin assembly includes a tooth adapter having a mount with a recess formed into a side of the mount. A lug is carried in the recess, and a tooth with a socket is configured to be fit onto the mount. The tooth includes a wall defining the socket, and a bore is formed through the tooth and along the wall. A pin is sized to be received in the bore and includes an axis, first and second sides opposed about the axis, a major notch corresponding in height to the recess, and a minor notch corresponding in height to the lug. 
     In another embodiment, a universal hammerless pin assembly for internally coupling pieces of heavy machinery includes a pin having a cylindrical sidewall, an internal hollow defined by an inner surface, opposed ends opening into the hollow, and lugs projecting inwardly inside the hollow from the inner surface. The assembly further includes spindles that have an inner end, an outer end, and an outer surface defining a constant diameter between the inner and outer ends. The spindles are snugly received in the hollow, and a groove formed in the outer surface is sized to receive the lugs. 
     In yet another embodiment, a universal hammerless pin assembly for internally coupling pieces of heavy machinery includes a pin having a cylindrical body, a reduced-diameter collar projecting therefrom, and a coaxial cylindrical socket formed into the body from the collar. A cap has a cylindrical head, a reduced-diameter shank projecting therefrom, and a shoulder disposed therebetween. Application of the cap on the body defines an inset circumferential channel formed by the collar of the pin and the shoulder of the cap. A washer is seated in the channel and has an inner diameter sized to encircle and be received in the channel. The washer is prevented from axial movement out of the channel by the body of the pin and the head of the cap. The washer defines an interference configured to be disposed between and prevent relative movement the pieces of heavy machinery. 
     The above provides the reader with a very brief summary of the detailed description presented below, and is not intended to limit or define in any way the scope of the invention or key aspects thereof. Rather, this brief summary merely introduces the reader to some aspects of the invention in preparation for the detailed description that follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring to the drawings: 
         FIG. 1  is a side perspective view of a pin assembly including a tooth adapter, a tooth, and a pin; 
         FIGS. 2 and 3  are side perspective views of the assembly of  FIG. 1 , illustrating the tooth being applied to the tooth adapter; 
         FIGS. 4A, 5A, and 6A  are section views taken along the line  4 - 4  in  FIG. 3  showing steps of rotating the pin of  FIG. 1  between the tooth and tooth adapter; 
         FIGS. 4B, 5B, and 6B  are section views taken along the lines  4 B- 4 B,  5 B- 5 B, and  6 B- 6 B in  FIGS. 4A, 5A, and 6A , respectively showing steps of rotating the pin of  FIG. 1  between the tooth and tooth adapter; 
         FIG. 7  is a side perspective view of a pin assembly including a pin and two spindles; 
         FIG. 8  is a side perspective of one of the spindles of  FIG. 7 ; 
         FIGS. 9A and 10A  are side perspective views of the pin assembly of  FIG. 7  in a contracted and expanded configuration, respectively; 
         FIGS. 9B and 10B  are section views taken along the lines  9 - 9  and  10 - 10  in  FIGS. 9A and 10A , respectively, showing the pin assembly of  FIG. 7  in a contracted and expanded configuration, respectively; 
         FIGS. 11A and 11B  are top perspective and top exploded perspective views, respectively of a pin assembly having a pin, a cap, and a washer; 
         FIG. 12  is an detail view of a portion of  FIG. 11B ; 
         FIGS. 13A, 14A, and 15A  are section views taken along the line  13 - 13  in  FIG. 11A , showing steps of rotating the cap on the pin; and 
         FIGS. 13B, 14B, and 15B  are section views taken along the lines  13 B- 13 B,  14 B- 14 B, and  15 B- 15 B in  FIGS. 13A, 14A, and 15A , respectively, showing steps of rotating the cap on the pin. 
     
    
    
     DETAILED DESCRIPTION 
     Reference now is made to the drawings, in which the same reference characters are used throughout the different figures to designate the same elements.  FIG. 1  illustrates a hammerless tooth adapter pin assembly  10  (“pin assembly  10 ”) for securing a tooth  11  onto a tooth adapter  12  that is secured to a shovel  13  of an earth-working machine. The pin assembly  10  includes the tooth  11 , the tooth adapter  12 , and a pin  14  that binds them. 
     The tooth adapter  12  is mounted to the shovel  13  with a separate retention assembly. The tooth adapter  12  includes upper and lower jaws  15  and  16  at a rear end of the tooth adapter  12  that flank the shovel  13  and attach thereto. The tooth adapter  12  further includes a front end  20  formed with a mount  21 . In  FIG. 1 , the mount  21  is shown as a triangular prism. The mount  21  is set into and extends from a front face  22  of the tooth adapter  12 . The mount  21  has a wide base  23  that tapers to a forward edge  24 , an oblique upper face  25 , an opposed oblique lower face  26 , and two sides  30  and  31 . 
     A recess  32  is formed into each of the sides  30  and  31 . The recesses  32  are identical, and as such, only one will be described herein, with the understanding that the description applies equally to the other. The recess  32  is semi-cylindrical, and extends inwardly into the mount  21  from the side  30 . The recess  32  is located generally intermediately between the base  23  and the forward edge  24  and extends between the upper and lower faces  25  and  26 . The recess  32  is open: it has an open top  33  and an open bottom  34 . A concave or arcuate sidewall  35  extends therebetween. 
     The sidewall  35  has a notch  36 . The notch  36  carries a key or a lug  40 . The lug  40  is releasably applied in the notch  36 , held in a snug fit arrangement. The lug  40  consists of a rigid, hard, and durable front, such as a chunk of metal, carried on an elastomeric backing. The lug  40  is carried in the notch  36  for depression; the elastomeric backing is snug fit into the notch  36  and compresses when a force bears down on the lug  40 , thereby causing the lug  40  to recede into the notch  36 . When the force is released, the elastomeric backing expands and returns to its original condition, causing the lug  40  to project into the recess  32 . 
     The tooth  11  is releasably applied to the mount  12 . Still referring to  FIG. 1 , the tooth  11  shown is highly generalized and not necessarily representative of a ripper tooth that might be used in the industry. Nonetheless, from the disclosure herein and the accompanying drawings, one having ordinary skill in the art will readily appreciate and understand the structure and operation of the tooth  11  herein. The tooth  11 , as shown, includes a body  41  having an outer wear surface  42 . The tooth  11  has opposed front and rear ends  43  and  44 ; at the rear end  44  is a socket  45  formed into the tooth  11 . The socket  45  is in the shape of a triangular prism and includes an upper surface  50 , a lower surface  51 , and opposed walls or sides  52  and  53 . Extending entirely through the tooth  11  from the top of the wear surface  42  through the bottom of the wear surface  42  is a bore  54 . The bore  54  is cylindrical but is aligned along the side  52 , such that as the bore  54  extends through the socket  45 , it defines a semi-cylindrical recess into the side  52 . Further, at the top of the wear surface  42  is a semi-cylindrical groove  55  encircling the half of the bore  54  that overlies the socket  45 . The groove  55  has opposed ends formed with blunt stops. 
     The tooth  11  is secured to the tooth adapter  12  with the pin  14 . With reference still to  FIG. 1 , the pin  14  is a generally cylindrical element having an axis A and two sides (“major side  60 ” and “minor side  61 ”) opposed about the axis A. The pin  14  has a sidewall  62  extending from a top  63  to a bottom  64  which is cylindrical but for two notches formed therein. A first, or major notch  65 , is formed into the major side  60 , and a second, or minor notch  66 , is formed into the minor side  61 . The major and minor notches  65  and  66  are both dados, formed latitudinally, or transversely to the axis A, across the major and minor sides  60  and  61 , respectively. The major notch  65  has an axially tall flat face, while the minor notch  66  has an axially short flat face. Both of the major and minor notches  65  and  66  are disposed generally intermediately between the top  63  and the bottom  64  of the pin  14 . Further, both of the major and minor notches  65  and  66  are open, such that they are not enclosed at their ends, the minor notch  66  includes a ramped entrance  67  (shown in  FIG. 4B ), wherein the entrance to the minor notch  66  is inclined to the flat face. In some embodiments, as shown in  FIG. 1 , the pin  14  includes a radially-projecting stub  70  at the top  63 . The stub  70  is a small, short, integrally-formed projection from the sidewall  62 . Also at the top is a socket  71  coaxially extending into the pin  14 . The socket  71  preferably has a hexagonal cross-section to receive a conventional tool. 
     Turning now to  FIGS. 2-6B , operation of the pin assembly  10  will be discussed.  FIGS. 2-6B  do not illustrate the shovel  13 , but one having ordinary skill in the art will readily appreciate the involvement of the shovel  13  based on his experience and knowledge, and description of the shovel  13  is thus not necessary herein. One having ordinary skill in the art will understand that the operation described below is preferably undertaken after the tooth adapter  12  has been applied to the shovel  13 , but the shovel  13  is removed for clarity of the illustrations.  FIG. 2  illustrates the pin  14  applied to the tooth  11  in a first applied condition. The pin  14  is applied into the first applied condition by aligning and registering the pin  14  with the bore  54 , with the bottom  64  of the pin  14  directed toward the top of the wear surface  42  of the tooth  11 . The pin  14 , so aligned, is then moved downward into the bore  54 . When the pin  14  is partially installed in the bore  54 , the pin  14  is received in the bore  54  for axial rotation, or rotation about its axis A. To place the pin  14  in a second applied condition, also shown in  FIG. 1 , the pin  14  is rotated so that the minor side  61  of the pin  14  is directed outwardly away from the socket  45 , so that the minor notch  66  is disposed against the semi-cylindrical recess  32  into the side  52  and the major notch  65  is directed into the socket  45 . The flat face of the major notch  65  is registered with and flush to the side  52  of the socket  45 . This defines the pin  14  being in the second applied condition. 
     In the second applied condition of the pin  14 , the pin  14  and the tooth  11  together are ready to be applied onto the tooth adapter  12 . The tooth  11  is thus moved over the mount  21  of the tooth adapter  12 . To do so, the sides  52  and  53  of the socket  45  are aligned with the sides  30  and  31  of the mount  21  and the tooth  11  is moved rearwardly along line B in  FIG. 2 , until the rear end  44  of the tooth  11  is flush in contact against the front face  22  of the tooth adapter  12 . The tall flat face of the major notch  65 , registered with the wall  52  of the socket  45 , moves in sliding contact against the side  30  of the mount  21 . 
     When the tooth  11  is applied over the mount  21  in this fashion, the pin  14  is in the third applied condition: the tooth  11  is received on the mount  21 , the pin  14  is received in the bore  54 , and the lug  40  is received in the major notch  65 . The lug  40  slightly spaced apart from the flat face of the major notch  65 , but is disposed in the major notch  65 . However, the major notch  65  has a height which is coextensive to the height of the recess  32 , and so the pin  14  may be rotated through the recess  32 . 
     Rotating the pin  14  axially in the recess  32  moves the pin  14  from the third applied condition to a fourth applied condition, in which the lug is received in the minor notch  66 , as shown in  FIG. 3 . When properly seated in the bore  54  with the stub  70  disposed in the groove  55 , the minor notch  66  is axially aligned with the lug  40 . The pin  14  may be rotated one hundred eighty degrees, limited in further rotation by the interaction of the stub  70  against the blunt end wall of the groove  55 . The pin  14  is rotated, and in doing so, the sidewall  62  bears against the lug  40  to compress the elastomeric backing and urge the lug  40  into the notch  41  until the flat face of the minor notch  66  opposes the notch  36 . When the pin  14  is fully rotated, the lug  40  does contact the end wall of the groove  55 , preventing further rotation, and indicating that the minor notch  66  now directly opposes the lug  40 . The elastomeric backing of the lug  40  expands back to its original condition and presses the metal front of the lug  40  into the minor notch  66 . 
     In this way, the lug  40  acts as a key in the minor notch  66 , allowing or preventing movement. When the lug  40  is received in the minor notch  66  in the fourth applied condition of the pin  14 , the semi-cylindrical sidewall  62  is snug fit into the semi-cylindrical sidewall  35  of the recess  32 . These two sidewalls  62  and  35  are complementary; the convex sidewall  62  is in full contact against the concave sidewall  35 . This prevents lateral movement of the tooth  11  with respect to the tooth adapter  12 . Movement along either direction on the line B of  FIG. 2  is prevented by interaction of the sidewall  62  against the sidewall  35 . Further, vertical movement of the pin  14  is prevented, because the minor notch  66  closely receives the expanded lug  40  therein. In this arrangement, the only way to remove the tooth  11  from the tooth adapter  12  is to rotate the pin  14  back to the third applied condition, where the lug  40  is received in the major notch  65  rather than the minor notch  66 . 
       FIGS. 4A-6B  show section views, some taken along the line  4 - 4  in different applied conditions of the pin  14 , which illustrate the interaction of the tooth  11 , the tooth adapter  12 , and the pin  14 .  FIG. 4A  shows the pin  14  in the third applied condition. There, the tooth  11  is received on the mount  21 . The pin  14  is within the bore  54 . The pin  14  is mounted for rotation and may be rotated in either direction. However,  FIG. 4A  does show the pin  14  with the major face  65  directed toward the lug  40 . The lug  40  is just spaced apart from the major face  65 . It is seen clearly here that the height of the major notch  65  and the height of the recess  32  correspond to each other, thereby allowing the pin  14  to be rotated through the recess  32 .  FIG. 4B  illustrates  FIG. 4A  from a top section view. 
       FIG. 6A  shows a step in this rotation. The pin  14  has been partially rotated, approximately ninety degrees, so that the sidewall  62  of the pin  14  bears against the lug  40  and compresses it.  FIG. 6B  shows the lug  40  slightly compressed as well. 
       FIGS. 5A and 5B  show the pin  14  in the fourth applied condition, in which the pin  14  is secured in the mount  21 , and the tooth  11  is securely captured on the tooth adapter  12 . There, the lug  40  is snugly received in the minor notch  66 , and the pin  14  is clearly prevented from upward and downward axial movement. 
       FIGS. 7-10B  illustrate a universal hammerless pin assembly  80  for coupling pieces of heavy machinery. The pin assembly  80  includes a pin  81  and two opposed, identical spindles  82  and  83 . The pin assembly  80  is useful for internally coupling those pieces of heavy machinery at a hole, a pivot, or a joint, and is useful for doing so without the need for special or proprietary tools and without engaging with special or proprietary features in the heavy machinery. The pin assembly  80  couples pieces of heavy machinery by engaging securely with itself, rather than with interfaces, slots, sockets, or other features in the heavy machinery, to form an engagement between the heavy machinery which will not release accidentally and which will not bind, corrode, or deteriorate with use. The pin  81  receives and holds the spindles  82  and  83 , which move out of and into the pin  81  to place the pin assembly  80  in an expanded and contracted configuration, respectively, as will be described, so as to engage and couple the pieces of heavy machinery. 
     Referring first to  FIG. 7 , the pin  81  is an elongate member including a cylindrical sidewall  84  extending from a first end  85  to a second end  86  along an axis. The sidewall  84  includes an outer surface  90  and an inner surface  91 . The inner surface  91  is generally smooth and featureless, except as described below, and bounds and defines an internal hollow  92 . The internal hollow  92  is long and cylindrical, extending entirely from the first end  85  to the second end  86 , such that the pin  81  is open at both the first and second ends  85  and  86 . An axial ridge  93  extends entirely along the pin  81  at the outer surface  90  and projects upwardly with a generally rectangular cross-section at the outer surface  90  of the sidewall  84 . The pin  81  is preferably formed from a single, unitary piece of rigid, hard, durable, and rugged material, such as steel or iron. 
     Referring now to  FIGS. 7 and 9B , two bores  94  and  95  are formed in the pin  81 , extending radially from the ridge  93  entirely through the sidewall  84  and the inner surface  91  of the pin  81 . The bores  94  and  95  are threaded proximate to the outer surface  90  and unthreaded proximate to the inner surface  91 , and receive lugs  100  and  101 , respectively. The lugs  100  and  101  are detents, which are catches that prevent motion with respect to the detents until the detents are released, compressed, or acted upon. The lugs  100  and  101  are identical. Each includes a threaded plug  102 , a rigid and hard head  103 , and a helical coil spring  104  compressed between the plug  102  and the head  103 . Each plug  102  has external threading and is threadably engaged with the threaded portion of the bores  94  and  95 . The plug  102  is engaged to a depth such that the back of the plug  102  is flush with the outer surface  90  at the ridge  93 . When so positioned, the head  103  just protrudes the bore  94  or the bore  95 . The spring  104  is a very rugged spring having a very thick gauge for compressing under high force. The spring  104  is captured in a socket  105  in the back of the head  103  and a socket at the leading end of the plug  102 , such that the lug  100  is held together. The heads  103  of the lugs  100  project inwardly inside the internal hollow  92  of the pin  81  to engage with the spindles  82  and  83  and secure the spindles  82  and  83  in expanded and contracted conditions. 
     The spindle  82  is shown in  FIG. 8 . The spindles  82  and  83  are identical in every respect but for application to the pin  81 , and as such, the following description will be of the spindle  82  only, with the understanding that the description applies equally to the spindle  83 . All reference characters used to identify the various structural elements and features of the spindle  82  are also used to identify identical structural elements and features of the spindle  83 , but are marked with a prime symbol (“′”) so as to designate and distinguish them from those of the spindle  82 . The spindle  82  has as a solid, cylindrical body  110 . The spindle  82  extends from a first end  111  to a second end  112  and has an outer surface  113  with several features configured for engaging with the pin  81 . The spindle  82  has a constant diameter between the first and second ends  111  and  112 . 
     Proximate to the second end  112  of the spindle  82 , a groove  114  is formed into the outer surface  113  of the spindle  82 , extending from just inboard from the second end  112  to a location generally intermediate between the first and second ends  111  and  112 . The groove  114  wraps helically around the outer surface  113  and is shallow. The groove  114  includes an elongate, flat groove face  115  and opposed first and second catches  116  and  117 . The first and second catches  116  and  117  are both circular and deep; they both extend deeper radially into the body  110  of the spindle  82  than the groove face  115  does, and the first catch  116  preferably extends into the body  110  the same depth as the second catch  117 . The first and second catches  116  and  117  thus define capture spots in the groove  114  for the lugs  100  and  101 . The first catch  117  is proximate to the second end  112  of the spindle  82 , while the second catch  116  is opposed, intermediately located to the first and second ends  111  and  112 . The groove  114 , including the face  115  and the first and second catches  116  and  117  are sized to receive the heads  103  of the lugs  100  and  101  therein. 
     Between the groove  114  and the second end  111 , or, in other words, distal to the groove  114 , two spaced-apart, parallel, continuous annular channels  120  and  121  extend radially into the body  110  of the spindle  82 . The channels  120  and  121  in  FIG. 8  are shown empty for clarity; however, in  FIG. 7 ,  FIG. 9B , and  FIG. 10B , the channels  120  and  121  hold gaskets  122  and  123 , as they normally would in operation. 
     A socket  124  is formed into the first end  111 . The socket  124  is preferably a square socket, but in other embodiments has a hexagonal or other shape, so as to accept a common and ubiquitous tool around a mining or construction site. The first end  111 , and the second end  112 , are both flat and perpendicular to the axis of the spindle  82 , so that when the spindle  82  is applied to the pin  81 , the first end  111  is flat and flush with the flat first end  85  of the pin  81 . The spindle  82  is preferably formed from a single, unitary piece of rigid, hard, durable, and rugged material, such as steel or iron. 
     In operation, the pin assembly  80  is useful for engaging two pieces of heavy equipment about a hole, bore, slot or like coupling point. The pin assembly  80  moves between the contracted configuration, shown in  FIGS. 9A and 9B , and the expanded configuration, shown in  FIGS. 10A and 10B , to couple the two pieces of heavy equipment. To prepare the pin assembly  80  for such use, the lugs  100  and  101  are first slightly backed out of the bores  94  and  95 , respectively, so that the heads  103  of the lugs  100  and  101  are flush with or inboard of inner surface  91 . The spindles  82  and  83  are initially in a free condition in which they are free of the pin  81 . The spindles  82  and  83  are then applied to the pin  81 , or placed into an applied condition. 
     Turning to  FIG. 7 , the spindle  82  is applied to the pin  81  by registered the second end  112  of the spindle  82  with the internal hollow  92  (discussion will continue with reference to the spindle  82  alone, with the understanding that identical application and operation of the spindle  83  is clear in light of the description of the spindle  82 ). The spindle  82  is aligned with the internal hollow  92 , such that the pin  81  and the spindle  82  are coaxially aligned. The outer diameter of the spindle  82  is just less than the inner diameter of the pin  81 , and the spindle  82  is applied into the internal hollow  92  by moving the spindle  82  axially forward along arrowed line C. 
     The spindle  82  is moved axially forward along line C until the first end  111  of the spindle  82  is flush with the first end  85  of the pin  81 . The lugs  100  and  101  are then slightly advanced by rotating them. This causes the lug  100  to either come into contact with the outer surface  113  of the spindle  82  or to slip into the first catch  116 . The user is able to feel whether the lug  100  is against the outer surface  113  or in the first catch  116 . If the lug  100  is against the outer surface  113 , the user merely needs to rotate the spindle  82  until the first catch  116  of the groove  114  is aligned with the lug  100 , at which point the lug  100  will pop into the first catch  116 , which extends radially deeper into the spindle  82  than does the face  115  of the groove  114 . Using a square wrench can be helpful in applying and rotating the spindle  82  in this manner. Once the spindle  82  is properly seated axially to the correct axial depth and the spindle  82  is rotated so that the lug  100  is aligned with the first catch  116 , the user then continues to turn the threaded plug  102  of the lug  100  until the back of the plug  102  is flush with the outer surface  90  at the ridge  93 , thereby ensures that the lug  100  is properly radially seated in the bore  94 . In this manner, the lug  100  exerts a sufficient bias on the groove  114  to prevent the spindle from accidentally rotating or moving axially.  FIGS. 9A and 9B  illustrate this arrangement. 
       FIGS. 9A and 9B  illustrate the contracted configuration of the pin assembly  80 . The spindles  82  and  83  themselves are in a contracted condition, wherein the spindle  82  is disposed in the internal hollow  92  of the pin  81 , the lug  100  is received in the groove  114 , and the first end  111  of the spindle is inside the internal hollow  92 . The spindle  82  does not project axially beyond the pin  81  and thus does not create an engagement or abutment beyond the pin  81 . Arranging the pin assembly  80  into the expanded configuration, in which the spindles  82  and  83  are in expanded conditions, does cause the spindle  82  to project axially beyond the pin  81  thereby creating an engagement or abutment beyond the pin  81 . Such an arrangement is shown in  FIGS. 10A and 10B . 
     Before the pin assembly  80  is placed into the expanded configuration, the pin assembly  80  is applied to a hole, bore, or slot defined between two pieces of heavy machinery. The pin assembly  80  occupies the bore in a space corresponding to one of the pieces of heavy machinery when in the contracted configuration. The heavy machinery pieces can be separated and are not coupled or secured to each other. To couple them, the pin assembly  80  must be moved to the expanded configuration. 
     Referring now to  FIGS. 10A and 10B , the pin assembly  80  is shown in the expanded configuration. To move the pin assembly  80  from the contracted configuration to the expanded configuration, the user takes up a square wrench and inserts it into the socket  124  of the spindle  82  and rotates the spindle  82  clockwise with respect to the pin  80  (as shown by the arcuate arrowed line D in  FIGS. 10A and 10B ). The user must place a sufficient amount of force on the spindle  82  to overcome the spring bias of the sprung head  103  in the first catch  116  of the groove  114 . When a sufficient amount of force is applied, the head  103  of the lug  100  moves rearward toward the bore  94  in interaction against the face  115  of the groove  114 , thereby compressing the lug  100 . The compressed lug  100  guides movement of the spindle  82 ; as the user rotates the spindle  82  clockwise, the lug  100  remains in and tracks the groove  114 , causing the spindle  82  to move axially out of the internal hollow  92  along the arrowed line E in  FIG. 10B . Rotation, and corresponding outward axial movement, is continued until the head  103  of the lug  100  pops into the second catch  117 , which extends radially deeper into the body  110  of the spindle  82  than does the face  115  of the groove  114 . 
     When the head  103  of the lug  100  is received in the second catch  117 , the channel  120  is located just inboard of the first end  85  of the pin  81 . The gasket  122  carried in the channel  120  thus provides a seal between the pin  81  and the spindle  82  to prevent the intrusion of dirt, dust, and debris, and the gasket  123  provides a redundant seal inboard of the gasket  122 . The first end  111  of the spindle  82  projects axially beyond the pin  81  and creates an engagement or abutment beyond the pin  81 . A piece of heavy machinery, received on another piece of heavy machinery in which the pin assembly  80  is carried, is now coupled to the other piece of heavy machinery: it cannot be moved laterally against the abutment of the projecting spindle  82 , and the spindle  82  is locked with the head  103  of the lug  100  in the second catch  116  and thus prevented from accidental movement. In this way, the pin assembly  80  is useful for coupling two pieces of heavy machinery. 
     A pin assembly  130  is illustrated in  FIGS. 11A-15B . The pin assembly  130  includes a pin  131 , a washer  132 , and a cap  133 . The pin assembly  130  is useful for internally coupling pieces of heavy machinery together at a hole or pivot joint, and is useful for doing so without the need for special or proprietary tools and without engaging with special or proprietary features in the heavy machinery. The pin assembly  130  couples pieces of heavy machinery by engaging securely with itself, rather than with interfaces, slots, sockets, or other features in the heavy machinery, to form an engagement between the heavy machinery which will not release accidentally and which will not bind, corrode, or deteriorate with use. 
     Referring primarily to  FIGS. 11A and 11B , the pin  131  has a cylindrical solid body  134  extending from a top  135  to a bottom  136 . The body  134  has a diameter which tapers from the bottom  136  to the top  135 , so that the diameter is largest at the bottom  136  and smallest proximate to the top  135 . The body  134  has an outer surface  140  which is generally smooth and featureless. 
     Proximate to the top  135 , a collar  141  projects upwardly from the body  134 . The collar  141  is a reduced-diameter, cylindrical extension integrally and monolithically formed with the body  134 . The body  134  and the collar  141  are coaxial. The collar  141 , because it has a smaller diameter than the body  134 , is inset from the outer surface  140  of the body  134 , and thus defines an annular shoulder  142  between the body  134  and the collar  141 . The shoulder  142  has a diameter equal to the diameter of the collar  141 . The collar  141  terminates in a flat, annular face  143 , which encircles an opening into a socket  144 . 
     The socket  144  of the pin  131  is a cylindrical recess formed coaxially into the body  134  from the face  143  of the collar  141 . The socket  144  extends axially approximately halfway into the pin  131 , includes a sidewall  145 , and terminates in an endwall  146 . The endwall  146  is featureless; the sidewall  145  is featureless but for a lug  150  that projects radially inward. The lug  150  is formed monolithically and integrally to the body  134  of the pin  131 . The lug  150  has a generally elongate shape, oriented along the axis of the pin  131 . 
     Still referring to  FIGS. 11A and 11B , the washer  132  is an annular ring with a front face  151  and an opposed rear face  152  (shown in  FIG. 2C ), an inner sidewall  153  defining a diameter G, and an outer sidewall  154 . It should be noted that “front” and “rear” are used only to identify and distinguish the front and rear faces  151  and  152  with common and easily understood modifiers, and not to indicate directionality of the pin assembly  130  or for any other such reason. The washer  132  is preferably constructed from a single, unitary piece of rigid, hard, durable, and rugged material, such as steel or iron. 
     The cap  133  includes a head  160  and a coaxial shank  161  projecting therefrom. The head  160  has a cylindrical outer surface  162  extending from a top  163  to a bottom  164 . The top  163  of the head  160  is flat and formed with a square socket  165  to receive a tool therein. The head  160  has a slightly tapering diameter from the bottom  164  to the top  163 , such that the top  163  is just slightly narrower than the bottom  164 . 
     The shank  161  projects from a shoulder  170  below the bottom  164  of the head  160 . The shoulder  170  steps the diameter of the head  160  at the bottom  164  of the head  160  down to the reduced diameter of the shank  161 . The shoulder  170  is an upstanding, coaxial, cylindrical projection on the head  160  and has an annular bottom surface  171  and a sidewall  172 . The head  160 , shoulder  170 , and shank  161  are preferably constructed integrally and monolithically from a rigid, hard, durable, and rugged material, such as steel or iron. 
     The shank  161  is a solid, cylindrical, and coaxial extension from below the shoulder  170 . The shank  161  has a diameter which is approximately half the diameter of the head  160  proximate to the bottom  164  of the head  160 . The diameter of the shank  161  is constant from a top  173  of the shank  161  to a bottom  174  of the shank  161 . An outer surface  175  of the shank  161  is featureless but for a groove  180  extending helically from the bottom  174  of the shank  161 . 
       FIG. 12  shows the groove  180  more clearly. The groove  180  extends from an open end  181  (shown in  FIGS. 13A, 14A , and  15 A) to a closed end  182 . The groove  180  wraps helically around the outer surface  175  of the shank  161  between the open end  181  and the closed end  182 , which is disposed approximately halfway between the top  173  and the bottom  174  of the shank  161 . The groove  180  includes an elongate, flat groove face  183  at the open end  181  and along the length of the groove  180 . The groove  180  terminates in a hold  184  proximate to the closed end  182 , but between the open and closed ends  181  and  182 . The hold  184  is an oblong recess formed radially into the body of the shank  161 , deeper than the flat groove face  183  and the open and closed ends  181  and  182 . The hold  184  is axially centered with respect to the closed end  182 , but is longer than the width of the groove  180  in the axial direction. 
     A detent  185  is carried in the hold  184 . Referring to both  FIGS. 12 and 14A , the detent  185  is snug fit into the hold  184  and includes an elastomeric backing  190  having a flat base  191 , and a rigid, hard, and durable front  192  with a rounded exterior  193 . The front  192  is preferably constructed from a slug of metal, such as a steel or iron. Two latitudinal ridges  194  and  195  are on the front  192 , extending latitudinally or transversely across the detent  185 . These ridges  194  and  195  are axially spaced apart by a distance corresponding to the width of the groove  180 . The detent  185  is carried in the hold  184  for depression; the elastomeric backing  190  is snug fit into the hold  184  both of which are flat, and compresses when a force bears down on the front  192  of the detent  185 , thereby causing the detent  185  to recede into the hold  184 . The elastomeric backing continuously exerts a bias directed radially outward from the shank  161 , however. When the force is released, the elastomeric backing  190  expands and returns to its original condition, causing the detent  185  to resume its original posture. 
     The pin assembly  130  is structured to be easily assembled and disassembled. The pin  131 , washer  132 , and cap  133  are coaxial and are constructed to quickly fit onto each other. The pin assembly  130  moves between a disassembled condition, shown in  FIG. 11B , and an assembled condition, shown in  FIG. 11A . In the assembled condition, the pin assembly  130  moves between an applied condition, shown in  FIGS. 15A and 15B , and an installed condition, shown in  FIGS. 13A and 13B .  FIGS. 13A-15B  show steps of moving the pin assembly  130  between the applied and installed conditions, in the assembled condition, as would be undergone when using the pin assembly  130  for internally coupling pieces of heavy machinery. 
     Turning to  FIG. 13A  first, the pin assembly  130  is shown in the assembled condition, and the installed condition thereof. In this arrangement, the pin assembly  130  binds two pieces of heavy machinery (not shown) together, preventing them from inadvertently decoupling.  FIG. 13A  is a section view taken along the line  13 - 13  of  FIG. 11A ;  FIG. 13B  is a section view taken along the line  13 B- 13 B of  FIG. 13A . The cap  133  is applied to the pin  131  with the washer  132  disposed therebetween. In this assembled condition, the collar  141  of the pin  131  and the shoulder  170  of the cap  133  cooperate to define a circumferential channel  200  in the pin assembly  130 , which extends slightly into the pin assembly  130  relative the outer surface  140  of the pin  131 . The channel  200  is an inset band in the pin assembly  10 , and has an inner diameter equal to the diameters of the collar  141  and the shoulder  170 . Thus, the channel  200  tightly receives the washer  132  thereon. The sides of the channel  200 , formed by the sidewall  172  and the collar  141 , prevent the washer  132  from moving axially out of the channel  200 . The collar  141  and the shoulder  170 , when brought proximate to each other in the assembled condition of the pin assembly  130 , form this engagement assembly, which lock the washer  132 , preventing axial movement of the washer  132  with respect to the pin  131  and the cap  133 . 
       FIGS. 13A and 13B  show the lug  150  captured in the closed end  182 , and thus, the pin assembly  130  in the installed condition. The lug  150  is kept in the groove  180  between the detent  185  and the closed end  182 . The lug  150  encounters laterally the closed end  182  on one side and the detent  185  on the other side, and thus is prevented from rotational movement. Because the lug  150  is formed integrally to the body  134  of the pin  131 , the pin  131  and cap  133  are thus also prevented from relative rotational movement. The lug  150  will not inadvertently move out of its kept position between the detent  185  and the closed end  182 , and thus the cap  133  is securely installed and carried on the pin  131 . In this configuration, the pin assembly  130  is effective at coupling pieces of heavy machinery. 
     To decouple the pieces of heavy machinery, the pin assembly  130  must be disassembled. The cap  133  must first move from the installed condition to the merely applied condition thereof, shown in  FIGS. 15A and 15B . To arrange the cap  133  that way, the cap  133  must be rotated in the pin  131 . A user takes up a wrench, such as a square wrench, and inserts it into the socket  165 . The user rotates the wrench in the socket  165  to rotate the cap  133  in the pin  131 . As shown in  FIG. 14A , the lug  150  encounters the detent  185 , forcing the detent  185  into compression within the hold  184 . The lug  150  is disposed axially between the ridges  194  and  195 ; this prevents the lug  150  from slipping. Further, the flat base  191  of the elastomeric backing  190 , compressed against the flat bottom of the hold  184 , prevents the detent  185  from rotating, flipping, or otherwise turning; the flat base  191  maintains the detent  185  in its proper arrangement with the front  192  presented radially outward. 
       FIGS. 14A and 14B  show the detent  185  compressed. The user continues to rotate the cap  133  in the pin  131 , causing the lug  150  to pop over the detent  185  into the groove  180  just opposite the closed end  182 . Released from the closed end  182 , the lug  150  can now move freely through the remainder of the groove  180 . Thus, in the applied condition shown in  FIGS. 15A and 15B , the user can continue to rotate the cap  133  with respect to the pin  131 . Because the groove  180  is helical, rotation of the cap  133  with respect to the pin  131  causes axial movement of the cap  133  out of the pin  131 . The lug  150  guides movement of the cap  133 ; as the user rotates the cap  133  clockwise, the lug  150  remains in and tracks the groove  180 , causing the cap  133  to move out of the socket  144  along the arrowed line F in  FIG. 15A . Rotation, and corresponding outward axial movement, is continued until the shank  161  is completely free of the pin  131 . At this point, the cap  133  is removed from the hole, bore, or slot that the pin assembly  130  is within, the overlying piece of heavy equipment is removed from the underlying piece, and the washer  132  and pin  131  are removed and replaced. 
     A preferred embodiment is fully and clearly described above so as to enable one having skill in the art to understand, make, and use the same. Those skilled in the art will recognize that modifications may be made to the described embodiment without departing from the spirit of the invention. To the extent that such modifications do not depart from the spirit of the invention, they are intended to be included within the scope thereof.

Summary:
Several hammerless pin assemblies for coupling pieces of heavy equipment include a pin that uses a detent to engage the pin between the pieces of heavy equipment. In one embodiment, a pin is inserted between a tooth adapter and a tooth, and rotates between a disengaged position in which the tooth can be applied and removed from the tooth adapter, and an engaged position in which the pin locks the tooth on the tooth adapter. In another embodiment, a pin receives two spindles which slide into and out of an internal hollow in the pin to present or hide an abutment for coupling the two pieces of heavy equipment. In yet another embodiment, a pin and a cap cooperate to capture a washer which prevents removal of the pin from between the heavy equipment and thereby couples the pieces of heavy equipment to each other.