Abstract:
A vibratory apparatus comprises an eccentric mass disposed within a housing. A shaft and bushing are received by the eccentric mass and couple the eccentric mass to a crankshaft. An internal conduit extends longitudinally within the shaft. Input and output conduits each communicate with the internal conduit to allow a lubricant to flow through the shaft. A bore extends radially through the bushing. Lubricant flowing through the shaft may further flow through the bore and form a lubricating layer between the bushing and the eccentric mass.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to orbiting mass vibrators, and in particular, to orbiting mass vibrators adapted for use on a rotary-vibratory drills or sonic drills. 
     In conventional orbiting mass vibrators adapted for use on rotary-vibratory drills, vibratory energy is generated by a pair of counter-rotating eccentric masses rotating along confined orbital paths within a housing. The eccentric masses are confined to the orbital paths by a cylindrical bore in the housing. Each eccentric mass is coupled to the housing and delivers vibratory forces to the housing. The housing in turn provides the vibratory output to a drill bit. However, if the eccentric masses and crankshafts are not properly aligned, excess vibratory forces may develop in the crankshafts. These excess vibratory forces may ultimately cause damage to the rotary-vibratory apparatus. It is therefore an objective of the invention to provide a self compensating mechanism which allows the eccentric masses and crankshafts to remain decoupled during the operation of the rotary-vibratory apparatus. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention there is provided a vibratory apparatus. The vibratory apparatus is comprised of a housing, an eccentric mass, a crankshaft, a first member, a second member and an operating mechanism for rotating the crankshaft. The crankshaft is rotatably mounted within the housing and the crankshaft is operatively connected with the eccentric mass. The first member is hollow and open at both ends. The first member also has an inner space and outer surface. The first member is received by the eccentric mass. The second member is received within the inner space of the first member and extends axially from the first member. The second member is connected with the crankshaft and the first member is allowed radial movement about the second member along a first axis. 
     According to another aspect of the invention, there is provided in combination a rotary drive apparatus, a drill string, and a vibratory apparatus. The vibratory apparatus is comprised of a housing, an eccentric mass, a crankshaft, a first member, a second member and an operating mechanism for rotating the crankshaft. The crankshaft is rotatably mounted within the housing and the crankshaft is operatively connected with the eccentric mass. The first member is hollow and open at both ends. The first member also has an inner space and outer surface. The first member is received by the eccentric mass. The second member is received within the inner space of the first member. The second member is connected with the crankshaft and the first member is allowed radial movement about the second member along a first axis. A liquid forms a lubricating layer between the first member and the eccentric mass. 
     This invention provides the advantage of allowing the eccentric mass and crankshaft of the vibratory apparatus to remain decoupled. Therefore despite imperfect machining of the components, machine wear or excess play of the crankshaft, the incidents of malfunction of the vibratory apparatus and damage to the vibratory apparatus are reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In drawings which illustrate embodiments of the invention: 
         FIG. 1  is a fragmentary, partly broken away, isometric view of a rotary-vibratory drill with a vibratory apparatus, according to an embodiment of the invention; 
         FIG. 2  is an elevational, partly broken away view of another rotary-vibratory drill with a vibratory apparatus, according to an embodiment of the invention; 
         FIG. 3  is an elevational, cross-sectional view of an eccentric system of a vibratory apparatus, according to an embodiment of the invention; 
         FIG. 4A  is an elevational side view of the first member of the eccentric system illustrated in  FIG. 3 . 
         FIG. 4B  is an elevational end view thereof; 
         FIG. 5A  is an elevational end view of the second member of the eccentric system illustrated in  FIG. 3 . 
         FIG. 5B  is an elevational side view thereof; and 
         FIG. 6  is a elevation end view illustrating the first member received by the second member. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings and first to  FIG. 1 , this shows this shows a rotary-vibratory drill  10  which is generally similar to a type already known in the art and disclosed in my earlier patents, namely U.S. Pat. No. 5,027,908 and U.S. Pat. No. 5,409,070, which are incorporated herein by reference. 
     The drill  10  is comprised of a vibratory apparatus  20 , a rotary drive apparatus  12 , and a drill string  14 . The drill string  14  is shown in fragment in  FIG. 1 . The vibratory apparatus  20  includes a pair of counter rotating eccentric masses  22  and  24  within a housing  21 . Eccentric mass  22  rotates in the direction indicated by arrow  23  and eccentric mass  24  rotates in the direction indicated by arrow  25 . The eccentric masses  22  and  24  are positioned relative to their axes of rotation such that they coincide at the tops and bottoms of their strokes, but are on opposite sides when midway between the tops and bottoms of their strokes. As a result, the vibrations imparted to the drill  10  by the eccentric masses  22  and  24  are additive in the vertical direction and subtractive in the horizontal direction, the net vibrating forces being in the vertical direction. 
     The eccentric masses are rotated on crankshafts, such as a crankshaft  30 . 1  shown in  FIG. 2  for eccentric mass  22 . 1 . Parts in  FIG. 2  have like numbers to those in  FIG. 1  with the additional numerical designation “1”. The crankshaft  30 . 1  is mounted at both ends within the housing  21 . 1  of the vibratory apparatus  20 . 1 . There is a splined socket  36  at the one end of the crankshaft  30 . 1 . The eccentric mass  22 . 1  is mounted on a crankpin  31 . 1 . The crankshaft  30 . 1  is rotated by a hydraulic motor  120  coupled to a first shaft  126  by gears  122  and  124 . A second shaft  40  operatively connects the crankshaft  30 . 1  to the first shaft  126 . The first shaft  126  has a splined socket  128 . The second shaft  40  has a first splined ball  42  which is received by the splined socket  128  on the first shaft  126 . The second shaft  40  has a second splined ball (not shown), similar to ball  42 , which is received by the splined socket  36  of the crankshaft  30 . 1 . The splined balls and sockets allow for vertical movement of the second shaft  40  as the vibratory apparatus vibrates. 
     In a preferred embodiment of the invention, each eccentric mass is part of its own eccentric system. The eccentric systems are generally equivalent notwithstanding the direction in which the eccentric mass rotates. Therefore, although the following disclosure is limited to a single eccentric system in a preferred embodiment of the invention, it is also applicable to the complementary counter-rotating eccentric system. 
     An eccentric system  11  of a preferred embodiment of the invention is best shown in  FIG. 3 . The eccentric mass  22 . 2  is a roller having a longitudinal bore extending therethrough. A first member  50  is received within the bore of the eccentric mass  22 . 2 . The first member  50  is a hollow elongated member which is open at both ends. In this embodiment of the invention the first member  50  is a bushing. A second member  70  is received within an inner space  54  of the first member  50  as seen in  FIGS. 3 and 6 . In this embodiment of the invention, the second member  70  is a shaft having a first end  71  and a second end  72 . The first end  71  and second end  72  of the second member  70  extend axially and outwardly from the first member  50  and the eccentric mass  22 . 2 . As seen in  FIG. 3 , the second member  70  is secured to a crankshaft  30 . 2  and brackets  61  and  62  by bolts  64  and  66 . Additional bolts are typically used as well but are not shown. 
     Rotation of the crankshaft  30 . 2  causes the eccentric mass  22 . 2  to rotate along an orbital path, thereby imparting vibratory forces to housing  21 . 1 , shown in  FIG. 2 , which in turn provides the vibratory output to a drill bit. 
     The first member  50 , according to the preferred embodiment of the invention, is shown in better detail in  FIGS. 4A and 4B . The first member  50  is a hollow elongated member having an open first end  51  and an open second end  52 . The inner space  54  extends the entire length of the first member and is rectangular in section, in this example. An outer surface  56  of the first member  50  is generally rounded and smooth. There is an annular recess  58  on the outer surface  54  of the first member  50  approximately midway between the first end  51  and the second end  52 . The recess  58  extends about a circumference of the outer surface  56 . There is a bore  59  located within the recess  58 . The bore  59  extends through the first member  50  from the outer surface  56  to the inner space  54  in a direction generally perpendicular to a longitudinal axis  55  of the first member. 
     The second member  70 , according to the preferred embodiment of the invention, is shown in better detail in  FIGS. 5A and 5B . The second member  70  is an elongated member comprised of a rectangular prism portion  84  flanked by a first cylindrical portion  80  at the first end  71  and a second cylindrical portion  82  at the second end  72 . There is an internal conduit  77  extending within the second member  70 . The internal conduit  77  is generally parallel to a longitudinal axis  89  of the second member  70 , as best shown in  FIGS. 3 and 5B . 
     Referring now specifically to  FIG. 5B , there is an input conduit  73 . The input conduit  73  extends into the second member  70  and communicates with internal conduit  77 , thereby allowing a liquid to flow into the internal conduit. In this example, the input conduit  73  extends into the first cylindrical portion  82  of the second member and is generally perpendicular to the longitudinal axis  89  of the second member  70 . 
     There is a circular indentation  86  located on a first side  85  of the rectangular prism portion  84  of the second member  70 . The first circular indentation  86  is approximately midway between the first end  71  and the second end  72  of the second member  70 . There is a ring shaped indentation  88  circumambient to, and concentric with, the circular indentation  86 . An output conduit  79  communicates with the internal conduit  77  and extends from the internal conduit to the circular indentation  86 , thereby allowing a liquid to be discharged from the internal conduit  77  to an outside environment. The output conduit  79  is concentric with the first circular indentation  86  and is generally perpendicular to the longitudinal axis  89  of the second member  70 . 
     The preferred embodiment of the invention, the eccentric system  11  is used to impart a vibratory output to a drill bit of a rotary-vibratory drill, or sonic drill. The eccentric system  11  operates as follows: 
     The second member  70  is received within the inner space  54  of the first member  50 , as shown in  FIGS. 3 and 6 . The rectangular prism portion  84  of the second member  70  is encompassed by the first member  50 . The cylindrical portions  80  and  82  of the second member  70  extend axially and outwardly from the first member  50 . As best shown in  FIG. 6 , a first extent or side  150  of the rectangular prism portion  84  of the second member  70  is generally equal to a first extent or side  152  of the inner space  54  of the first member  50 . A second extent or side  154  of the rectangular prism portion of the second member  70  is relatively shorter than a second extend or side  156  of the inner space  54  of the first member  50 . The second extents  154  and  156  are generally perpendicular to their corresponding first extents  150  and  152 . This arrangement allows radial movement of the first member  50  relative to the second member  70  in the direction generally indicated by arrows  115 . Movement of the first member relative to the second member in other directions is restricted. When the eccentric system is operational, the combination of the first member  50  and second member  70  are rotated by a crankshaft in the direction generally indicated by arrow  117 . 
     Referring back to  FIG. 3 , brackets  61  and  62 , held in place by bolts  64  and  66 , clamp the first and second cylindrical portions  80  and  82  of the second member  70  to the crankshaft  30 . 2 . The second member  70  is therefore coupled to the crankshaft  30 . 2 . The first member  50  is allowed similar radial movement, relative the second member  70 , and is therefore similarly decoupled from the crankshaft  30 . 2 . The eccentric mass  22 . 2  is also allowed radial movement, relative the second member  70 , and is similarly decoupled from the crankshaft  30 . 2 . The first member  50  and eccentric mass  22 . 2  are allowed movement along a first axis  110  in a direction indicated generally by arrows  130 . The first axis  110  is generally perpendicular to the longitudinal axis  89  of the second member  70 . 
     Rotation of the crankshaft  30 . 2  causes the eccentric mass  22 . 2  to rotate along an orbital path. The rotating eccentric mass  22 . 2  imparts vibratory forces to a housing, such as housing  21 . 1  shown in  FIG. 2 . The housing in turn provides the vibratory output to a drill bit (not shown). In known rotary-vibratory drills, or sonic drills, imperfections in the tolerances between adjacent parts may cause stress on a crankshaft when the crankshaft is rotating an eccentric mass. However, in eccentric system  11  the eccentric mass  22 . 2  and the crankshaft  30 . 2  are decoupled. As such, the eccentric mass  22 . 2  and the crankshaft  30 . 2  are able to self-align and compensate for any imperfections in tolerances. The eccentric mass  22 . 2  can therefore be rotated within a housing, such as housing  21 . 1  shown in  FIG. 2 , without stressing the crankshaft  30 . 2 . The net result being that only the eccentric mass  22 . 2  transmits radial forces to the housing. 
     An additional feature of the preferred embodiment of the invention is that a liquid may be introduced to the eccentric system  11 . As best shown in  FIG. 3 , the liquid is pumped by a pump  143  from a reservoir  145 , along a supply conduit  140 , to the crankshaft  30 . 2 . The supply conduit  140  is in communication with a first end of a crankshaft conduit  147 . The crankshaft conduit  147  extends through the crankshaft  30 . 2 . A second end of the crankshaft conduit  147  is in communication with the input conduit  73  of the second member  70 . The liquid flows through the crankshaft  30 . 2  along the crankshaft conduit  147  and into the second member  70 . The liquid flows through the second member  70  and is discharged through the output conduit  79  of the second member and through the radially extending bore  59  of the first member  50 . The liquid flows over the outer surface  56  of the first member  50 , as indicated generally by arrows  161  and  163  in  FIG. 4A , acting as lubricant between the first member  50  and the eccentric mass  22 . 2 . In this embodiment of the invention the liquid is an oil. 
     It will be understood by someone skilled in the art that many of the details provided here are by way of example only and can be varied or deleted without departing from the scope of the of the invention as set out in the following claims.