Patent Document

TECHNICAL FIELD OF INVENTION 
       [0001]    The present invention relates to a misalignment-compensating bushing system for use in apparatus for subterranean exploration. The present invention may be retrofitted to an existing large scale apparatus, such as the equipment used in connection with oil field operations. In particular, the invention provides misalignment compensation in an apparatus that has several large scale components, such as lugs, mounted side-by-side to a single pin where one lug rotates about the pin while others are immobile on the pin. 
       BACKGROUND OF THE INVENTION 
       [0002]    In engineering machinery, it is often useful to mount components to a common pin, where one rotates relative to other stationary components mounted to the common pin. Such pins are frequently used in heavy engineering structural machines, such as mechanical structures used in exploration for oil, gas and geothermal energy, drilling operations, pipe handling equipment, and the like. In heavy engineering equipment, the alignment of multiple large and heavy components on a single common pin, presents several design issues. For example, it is readily apparent that an angular misalignment at the pin that might be within an expected tolerance, when traced along a length of a structure extending several meters (or feet) from the pin may result in the far end of the component extending several inches out of its intended position. This might be sufficient to interfere with other components aligned on the same pin and may cause excessive wear on mechanical components due to cyclical uneven loads, or may even cause a catastrophic collision with other equipment or workers. 
         [0003]    It is desirable from the standpoint of mechanical reliability to ensure that all heavy mechanical components mounted to a pin are aligned as near perfectly on the pin as possible. One approach to improving alignment is to alter the shape of the pin to use its shape to assist in alignment. However, such multi-shaped pins are more expensive to manufacture with precision, and present additional engineering challenges of their own. More commonly, large cylindrical pins are used as being easier to control dimensionally, and less expensive to make and to inventory. Accordingly, other technologies are needed that may be used with a cylindrical pin. Desirably, these technologies should also minimize or compensate for misalignment of components mounted on the pin. 
         [0004]    In some circumstances, once components are mounted to a load bearing pin, the components and the bushing assembly have to be tightened at both ends of the pin to lock all the component parts together. However, in many situations, one side of the assembly may not be readily accessible. Accordingly, there is a need for a rotatable bushing connection system that permits tightening from one side only and that also minimizes or compensates for any misalignment of components mounted on the pin. Still further, there is a need for a rotatable bushing connection system that does not require any modification to the components being mounted. 
       SUMMARY 
       [0005]    The following is a summary of some aspects and exemplary embodiments of the present technology, of which a more detailed explanation is provided under the Detailed Description section, here below. 
         [0006]    The invention provides a rotary misalignment-compensation bushing connection system that may be used in large scale operation where several components must be mounted side-by-side in alignment on a single pin, and where one of the components rotates about the pin. For example, the misalignment-compensation system may be used in preloaded connection of a male lug rotatably mounted between stationary first and second lugs, on heavy equipment, for example, oil field exploration and production equipment or other heavy machinery. 
         [0007]    In an exemplary embodiment, the misalignment-compensating rotary bushing connection system has a second threaded hole in the second end of the pin. A center spacer is located over the pin and is substantially centered along the length of the pin. The system also includes a pair of sleeve bearings, one located on each side of the center spacer and surrounding at least a portion of the pin. An inner cone bushing is located on each sleeve bearing, and an inner cup bushing is located on each inner cone bushing. The system has a pair of thrust bearings located on the pin, and extending at least partially circumferentially around the pin, each of the thrust bearings positioned adjacent to a sleeve bearing on an outboard side of the inner cone bushings. In addition, the exemplary misalignment-compensating rotary bushing connection system has a pair of outer cone bushings located on and surrounding the pin. The second outer cone bushings are each adjacent to an outboard side of a thrust bearing. An outer cup bushing is located on top of and is located on each outer cone bushing. Further, the connection system includes a first and a second retainer cap, each having an internal side and an external side, and a connecting passage from the internal to the external side. The internal side of each cap has a compression boss, and a relief receivable of one of the ends of the pin. The external side of the cap is configured to engage a fastening tool, and has a radial slot or bore receivable of a locking pin. 
         [0008]    In the above exemplary embodiment, each of the pairs of inner cup bushings and inner cone bushings have a first complementary counter-taper, and each of the pairs of the outer cup bushings and the outer cone bushings have a second complementary counter-taper. Accordingly, when the connection system is assembled, and tightened with a fastening tool, the first and second complementary counter-tapers, respectively, permit sliding engagement and expand the diameter of the exemplary embodiment. As the diameter expands during tightening, the bores of the lugs are engaged, and the lugs are urged into proper alignment. 
         [0009]    In exemplary embodiments, grooves may be applied to outer surfaces of any one or more of the inner cone bushing, the inner cup bushing, the outer cone bushing and the outer cup bushing. Moreover, in other exemplary embodiments, slots shorter than an axial length of the cone bushing may be provided, for example, extending axially through a thickness of the outer cone bushings, and extending from opposite ends of the outer cone bushings. 
         [0010]    In exemplary embodiments, low friction coatings may be applied selectively to certain of the inner and outer bores of the cones and the inner bores of the cups; these coatings, in combination with the utilization of higher friction surfaces on some elements, can be utilized to ensure full makeup of all elements of the assembly without requiring excessive axial force applied through the tightening mechanism. 
         [0011]    In an alternate embodiment, the pin may have a first portion and a second portion. The first portion may be substantially cylindrical, and the second portion may be substantially frusto-conical in shape, with cone diameter increasing with distance from the first portion. The outer surface of the second portion edge is separated from the outer surface of the first portion by a ledge having a radial depth. The frusto-conical second portion replaces one of the outer cone bearings of the embodiment described. Further this embodiment only requires a single retainer cap. 
         [0012]    In other exemplary embodiments, the retainer cap may be configured in a variety of different ways to prevent rotation of the retainer cap relative to the center pin when a fastener is torqued into the threaded bore of the pin. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The foregoing aspects, and many of the attendant advantages, of the present technology will become more readily appreciated by reference to the following Detailed Description, when taken in conjunction with the accompanying simplified drawings of exemplary embodiments. The drawings, briefly described here below, are not to scale, are presented for ease of explanation and do not limit the scope of the inventions recited in the accompanying patent claims. 
           [0014]      FIG. 1  is an illustration depicting a first exemplary embodiment of the misalignment-compensating rotary bushing connection system. 
           [0015]      FIG. 2  is a cross sectional view of the first embodiment. 
           [0016]      FIG. 3  is an exploded view showing detail of the components of the first embodiment. 
           [0017]      FIG. 3A  is an exploded view showing detail of certain components (shown on the right-hand side in  FIG. 3 ) of the first embodiment. 
           [0018]      FIG. 3B  is a cross section through a portion of an exemplary inner cup bushing (shown on the right-hand side in  FIG. 3 ) of the first embodiment showing the internal taper angle. 
           [0019]      FIG. 3C  is an illustration of an exemplary outer cone bushing of the first embodiment showing the external taper angle. 
           [0020]      FIG. 4  is an illustration depicting a second exemplary embodiment of the misalignment-compensating rotary bushing connection system. 
           [0021]      FIG. 5  is a cross sectional view of the second embodiment. 
           [0022]      FIG. 6  is an exploded view showing detail of the components of the second embodiment. 
           [0023]      FIG. 7  is an illustration depicting a third exemplary embodiment of the misalignment-compensating rotary bushing connection system. 
           [0024]      FIG. 8  is a cross sectional view of the third embodiment. 
           [0025]      FIG. 9  is an illustration depicting a fourth exemplary embodiment of the misalignment-compensating rotary bushing connection system. 
           [0026]      FIG. 10  is a cross sectional view of the fourth exemplary embodiment. 
           [0027]      FIGS. 11A-11E  illustrate in more detail the assembly of a retainer cap of the fourth embodiment. 
           [0028]      FIGS. 12A-12D  illustrate in more detail an exemplary embodiment of the misalignment-compensating rotary bushing connection system being inserted from one end of a series of lugs and tightened from one end to affix the embodiment in position. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0029]    The following non-limiting detailed descriptions of examples of embodiments of the invention may refer to appended Figure drawings, but are not limited to the drawings, which are merely presented for enhancing explanations of features and aspects of the inventive technology. In addition, the detailed descriptions may refer to particular terms of art, some of which are defined herein, as appropriate and necessary for clarity. 
         [0030]    In exemplary embodiments of the misalignment-compensating rotary bushing connection system there are generally a pair of inner cup-and-cone bushings that are nested together and are located axially side-by-side, each on a sleeve bearing that is located on either side of a center of the central pin of the connection system. A spacer is also located on the pin, between each set of inner cup-and-cone bushings. The inner cup-and-cone bushings bear on a lug (or pair of lugs) that rotates around the pin, and the inner cup-and-cone bushings (and the sleeve bearings) rotate with the lug around the pin. Accordingly, structure and surfaces are utilized to promote this motion, and to maximize slippage with respect to the pin, for the sake of efficiency. In contrast, the exemplary embodiments also have a pair of outer cone-and-cup bushings (or cup-on flared-pin-end) combinations that bear on lugs that are immobile. Thus, for these components, slippage is minimized between the pin and these components. The non-rotating components are axially separated from the rotating components by a pair of thrust bearings, thus minimizing slippage between the rotating and non-rotating components, i.e., the inner cup-and-cone bushings and the outer cup-and-cone bushings. 
         [0031]    A first exemplary embodiment  100  of the misalignment-compensating rotary bushing connection system is shown in  FIGS. 1 ,  2 ,  3 , and  3 A-C. The first embodiment is symmetrical about the vertical axis V. Accordingly, the description that follows may focus at times on only one side of V, but applies to the other side as well. In addition, locations closer to the vertical axis V are termed “inboard” relative to those farther from the axis V, which are termed “outboard.” The first embodiment is configured for preloaded connection of a male lug that is rotatably mounted between a first immobile lug and a second immobile lug (also called female lugs). In embodiment  100 , there is a central, substantially-cylindrical pin  10  configured to fit within a bore in a series of male and female lugs, such that the central male lug only rotates about the pin. Pin  10  has a threaded hole  12  in each of its two ends  14 . These threaded holes  12  are off center, in this embodiment, by a distance c, as depicted. The distance c is approximately 3 to 10% of the diameter of pin  10 . The offset c permits the entire assembly  100  to be immobilized from one end to allow a fastener to be screwed into the threaded hole  12 . In addition, the circumferential edges of ends  14  are chamfered, for example, at an angle of about 45 degrees or a larger or smaller angle. 
         [0032]    As best seen in the illustrated embodiment in  FIG. 3 , an annular central spacer  20  is located on the pin  10 . Spacer  20  has a T-shaped cross. In other embodiments, a spacer may be omitted or have a different cross-sectional shape to accommodate the particular bore characteristics of a lug being mounted. Spacer  20  is flanked on each side by a sleeve bearing  30  that is located on the surface of pin  10  and rotates about the pin. An annular inner cone bushing  40 , seen in more detail in  FIG. 3A , is located on the outer surface of each of the sleeve bearings  30 . Referring to  FIG. 3A  (showing components located on the right-hand side of  FIG. 3 ), the inner surface  44  of cone bushing  40  is substantially cylindrical, allowing it to fit in complementary engagement onto the outer cylindrical surface of sleeve bearing  30 . The outer surface  45  of the inner cone bushing  40  is frusto-conical and tapers along its axial length, from the outboard side to the inboard side. Thus, the inner cone bushing  40  has a greater thickness on one side than on the axially opposite side. The taper of cone bushing  40  is α degrees, which may vary from 5 to 25, and desirably 15 degrees, in some embodiments, but may be more or less. Inner cup bushing  50  has a substantially cylindrical outer surface  55  and an inner surface  54  having a taper complementary to that of the outer surface  45  of inner cone bushing  40 . Thus, it has an inner taper of α degrees, and has a complementary counter-taper to the outer surface  55  of inner cup bushing  50 , as seen in  FIGS. 3A and 3B . Outer surface  55  may be equipped with grooves  52  to increase friction with the bore of a lug that is mounted to the first embodiment. During fastening, by torqueing a fastener  90  at each end of the assembly, as explained later, the complementary counter-tapers of inner cone bushing  40  and inner cup bushing  50  are urged into engagement. As they are urged into engagement, the inner cone bushing is forced under the inner cup bushing, thus expanding the diameter of the inner cup bushing, which allows it to grip the bore of an attached lug. Inner cup bushing  50  may further have an expansion joint  57  for this purpose. 
         [0033]    On the outer (outboard) sides of each of the inner cone bushings  40  and inner cup bushings  50  is a thrust bearing  15 , that has a substantially annular shape and that extends around the outer circumference of pin  10 . As seen more clearly in  FIG. 3A , each of the pair of thrust bearings  15  has a notch  17  of depth h that runs all around one of its circular side surfaces, and that is configured and sized to avoid contact with outer cone bushing  70 , thereby minimizing frictional drag on the outer cone-and-cup assembly (discussed below), which is immobile, when the inner cup-and-cone bushing assembly rotates along with sleeve bearing  30  as the male lug rotates. Thrust bearing  15  also interfaces with inner cone bushing  40 , and rotates in concert with it. Accordingly, the face of thrust bearing  15  that contacts inner cone bushing  40  may be treated to increase friction and enhance grip between these two components. Annular outer cone bushing  70  is located on the outer surface of pin  10 , outboard of the sleeve bearing  30  and the thrust bearing  15 , and it is located on the pin&#39;s outer surface. Also, because the thrust bearing  15  only interfaces with the outer cup bearing  60 , thrust loads are transmitted to the female lug through the shortest and stiffest load path, thus reducing the loads transmitted through the remainder of the outboard assembly which would tend to reduce the clamping friction of the outer cone bushing  70  in the outer cup bearing  60 . The outer frusto-conical shaped cone bushing  70  is an annulus that has an inner surface  74  that is cylindrical and sized and configured to fit over the outer surface of pin  10 . The inner surface  74  may be treated to increase friction between it and the pin to prevent pin  10  from rotating freely beneath the inner surface  74 . As shown in more detail in  FIG. 3C , the outer cone bushing  70  has a frusto-conical taper at an angle of β, of between 5 and 25 degrees or more. The outer surface  75  is oriented with the narrow end of the taper inboard from the thicker end of the taper. As shown, the outer cone bushing  70  may include a series of axially extending slots  72 , shorter that the axial length of the bushing  70 , and extending through the thickness of the bushing and alternating by extending axially from one end, then from the other end of the bushing. In addition, the inner surface  74  of the bushing is offset from the outer surface and the outboard (or thicker) edge of the bushing to form a ring-shaped depression  76  that has an (axial) depth d. The depression  76 , of depth d, is sized and configured to receive at least a portion of a leading end  84  of retainer cap  80 . When torqueing the fastener, the leading edge  84  engages within the depression  76 , and the outer cone bushing is locked into place. 
         [0034]    An annular outer cup bushing  60  is located on the outer cone bushing  70  and interfaces with the thrust bearing  15 . As shown, in the example, the outer cup bushing  60  has a tapered inner surface  64  at an angle β, selected to match the taper of the outer surface  75  of the outer cone bushing  70 . Thus, as in the case of inner bushings  40  and  50 , the tapers are complementary and serve the same function of correcting any misalignment as they are urged into engagement by torqueing fastener  90  during assembly. The outer surface  65  of outer cup bushing  60  may include a series of grooves  62 , both axial and circumferential, to minimize slippage the bore of a lug. Outer cup bushing  60  may further have an expansion joint  67  to allow for it to expand in diameter and engage the bore of an attached lug. 
         [0035]    A retainer cap  80  is fitted onto each of the ends  14  of pin  10 . Referring back to  FIG. 2 , retainer caps  80  are substantially cylindrical and each has an internal surface  82  that is sized and configured to receive one end  14  of the pin  10 . Leading edges  84  of cap  80  extend beyond edges  14  of pin  10 . Thus, retainer cap  80  receives and encapsulates ends  14  of pin  10 . The outer surface  85  of cap  80  includes a through bore  86  forming a connecting passage from the internal to the external side. The through bore  86  has a countersunk head  87  at the outboard end to receive the head of a fastener  90 . Moreover, in the example shown, the outer surface  85  is configured to engage a tool, while the fastener  90  is being torqued, to prevent rotation of the entire assembly  100  and permit threadingly driving the fastener  90  into the threaded bore  12  of pin  10  and thereby urging all components into aligned position. Thus, for example, the outer surface  85  has a pair of spaced apart flats  88  that can be gripped by a wrench so that the retainer cap is held immobile, while the fastener  90  is driven by another tool inserted into its socket  96  so that its threaded shank  92  enters the threaded bore  12  of the pin, and the head  94  enters the countersunk portion  87 . During torqueing, the inner surface  84  of cap  80  functions as a compression boss urging all the components of the bushing connection system  100  axially. The urging drives the inner cone-and-cup bushings into complementary counter-tapered engagement, and the outer cone-and-cup bushings into complementary counter-tapered engagement. As the cone-and-cup bushings are urged into alignment, their external diameters increase thereby gripping the bores of the lugs that are being mounted. Torqueing (and urging) is continued until the rotary bushing connection system is fully aligned and secured in place. At that stage, a locking pin  95  is inserted through a radially extending bore in cap  80  (not shown) and through a bore  98  in fastener  90 , when these bores are lined up into registration with each other. 
         [0036]    A second exemplary embodiment  200  of the misalignment-compensating rotary bushing connection system, one having only a single retainer cap, and thus allowing use in situations where both sides of the assembly cannot be reached, is shown in  FIGS. 4 ,  5 , and  6 . In the second embodiment  200 , a central rotatable lug or lugs may be mounted to surfaces  255 , while immobile lugs may be mounted to surfaces  265 . The second embodiment  200  has a pin  210  that has a threaded bore  212  at only one end  214 . The pin  210  has a substantially cylindrical first section  216  and a second section  218  that is substantially frusto-conical. The second section  218  has a cross sectional diameter increasing with distance from the first section  216 . The taper angle of the outer surface γ may be from 5 to 25 degrees, and preferably 15 degrees, but may be greater or less. And, the second section  218  is separated from the first section  216  by a ledge having a radial depth r. The radial depth r, in the example shown, approximates the thickness of the sleeve bearings  230 . The outer surface of the second section  218  may be supplied with grooves  219 . The end  214  of the first section  216  has a threaded bore  212  that may be off-center by an amount c as shown. In addition, the circumferential edges at end  214  of pin  210  are chamfered, for example, at an angle of about 45 degrees, or a larger or smaller angle. 
         [0037]    In the illustrated embodiment, an annular central spacer  220  is located on the first section  216  of pin  210 , and is located on the circumference of pin  210 . Spacer  220  is flanked on each side by an annular sleeve bearing  230  that is located on the surface of pin  210 , and is located on the circumference of pin  210 . Annular sleeve bearing  230  rotates about the pin  210 . An annular inner cone bushing  240  is located on the outer surface of each of the sleeve bearings  230 , and fits snugly on the outer surface of the sleeve bearings  230 . The inner surface  244  of cone bushing  240  is substantially cylindrical to fit tightly onto the outer cylindrical surface of sleeve bearing  230 . But, the outer surface  245  of the inner cone bushing  240  tapers from the outboard side of the annular shape to the inboard side, so that the inner cone bushing  240  has a greater thickness on one side than on the axially opposite side. The taper of cone bushing  240  is α degrees, which may vary from 5 to 25, and desirably 15 degrees, in some examples, but may be more or less. Inner cup bushing  250  is substantially annular in shape and has an inner surface  254  that has a taper complementary to that of inner cone bushing  240 . Thus, it has an inner taper of α degrees. The outer surface  245  of inner cup bushing  240  is substantially cylindrical in shape and may be equipped with axial and circumferential grooves  242  to increase friction with an attached lug. During fastening, by torqueing a fastener  290 , the complementary counter-tapers of the inner cone and inner cup bushings are urged into engagement and this engagement facilitates correcting for any misalignment by re-aligning components. Inner cup bushing  250  may further have an expansion joint  257  to allow its diameter to expand and engage the bore of an attached lug during assembly. 
         [0038]    On each side of the inner cone bushings  240  and inner cup bushings  250  is a thrust bearing  215  that has a substantially annular shape that extends around the outer circumference of the first section  216  of pin  210 . Each thrust bearing has a notch that runs all around one of its circular side surfaces, and that is configured to avoid contact with outer cone bushing  260  or the second section  218  of pin  210 , thereby minimizing frictional drag on the outer assemblies, which are immobile, when the inner cup-and-cone bushing assembly rotates along with sleeve bearing  230  about the pin. Thrust bearing  215  also interfaces with inner cone bushing  240 , and rotates in concert with it. Accordingly, the interface of thrust bearing  215  with inner cone bushing  240  may be treated to increase friction and enhance grip between these two components. Similarly, the interface between thrust bearings  215  and outer cup bushings  260  may be treated to reduce friction and increase slippage to reduce drag from the rotating components. Also, because the thrust bearing  215  only interfaces with the outer cup bearing  260 , thrust loads are transmitted to the female lug through the shortest and stiffest load path, thus reducing the loads transmitted through the remainder of the outboard assembly which would tend to reduce the clamping friction of the outer cone bushing  270  in the outer cup bearing  260 . 
         [0039]    Unlike the first embodiment  100 , the second embodiment  200  only requires a single annular outer cone bearing  270  because the frusto-conical section  218  of pin  210  performs the function of a second outer cone bearing. As such, only a single outer cone bushing  270  is located on the outboard side of the thrust bearing  215  that is farthest from section  218 . Outer cone bushing  270  is located on the pin&#39;s outer surface and may be treated to maximize friction with the pin&#39;s surface to prevent the pin from sliding freely, so that an attached lug remains immobile. The outer cone bushing  270  is a frusto-conical-shaped annulus that has an inner surface  274  that is cylindrical and sized and configured to fit over the outer surface of pin  210 . The outer surface  275  of outer cone bushing  270  has a taper at an angle of β, of between 5 and 25 degrees or more. The outer surface  275  is oriented with the thicker end of the taper nearer to the end  214  of pin  210 . As shown, the outer cone bushing  270  may include a series of slots  272  extending through the thickness of the bushing and alternating by extending axially from one end, then from the other end of the bushing. The slots  272  are shorter than the axial length of the bushing  270 . In addition, the inner surface  274  of the bushing is offset from the outer surface  275  at the thicker edge of the bushing by a circumferentially extending ring-shaped depression  276  that has an (axial) depth d. The depression  276  of depth d is sized and configured to receive at least a portion of a leading end  284  of retainer cap  280 . When torqueing the fastener  290 , the leading edge  284  engages within the depression  276 . 
         [0040]    On the side of the inner cone bushing  240  that is located farthest from end  214  of the pin, and nearest to the second section  218  of the pin, as indicated above, is a thrust bearing  215 , which is separated from the ledge that separates the first section  216  from the second section  218  of pin  210 . The second section  218  of pin  210  has an outer surface that tapers at an angle γ and it is surrounded by an annular outer cup bushing  260  that has an inner surface  264  tapered at a like angle. The outer surface  265  of the outer cup bushing  260  may be cylindrical, and may be supplied with grooves  262  to increase friction with the bore of a lug. The inner surface  264  of the outer cup bushing may also be treated to increase friction and decrease slippage. Outer cup bushing  260  may further have an expansion joint  267  to allow for it to expand in diameter and engage the bore of an attached lug. 
         [0041]    A retainer cap  280 , like that described for the above exemplary embodiment, or one of a different design, may be fitted onto end  214  of pin  210 . During torqueing, the inner surface  284  of cap  280  functions as a compression boss urging all the components of the bushing assembly  200  axially toward the farther end of second section  218 . The urging forces the inner cone-and-cup bushings into complementary tapered engagement, and the outer cone-and-cup bushings into complementary tapered engagement. This causes the cone-and-cup bushings&#39; diameters to increase. Torqueing (and urging) is continued until the rotary bushing assembly is fully aligned and secured in place. At that stage, a locking pin  295  is inserted through a radially extending bore in cap  280  (not shown) and through a bore  298  in fastener  290 , when these bores are lined up into registration with each other. 
         [0042]    A third exemplary two-ended embodiment  300  of the misalignment-compensating rotary bushing connection system is illustrated in  FIGS. 7 and 8 . The embodiment is symmetrical about a central vertical axis V. In this exemplary embodiment of the rotary misalignment-compensation bushing connection system  300 , a central pin  310  passes through a first outer lug A, and a second outer lug B, as well as a central lug C, that is equipped with a bearing  330 , in this example shown as a spherical bearing. The exemplary embodiment compensates for any misalignment and provides appropriate alignment between the three lugs, A, B and C. Lugs A and B are immobile relative to the pin, while lug C moves about the pin. The central cylindrical pin  310  has a pair of ends  314 , that each has a chamfered circumferential edge, and a threaded off-center hole  312  for receiving a threaded shank of a fastener  390 . The bearing  330  is centered along the axis of pin  310  and is flanked by annular spacers  320  located on the pin  310 . Each of the spacers  320  is in turn flanked on the outboard side by an axially-tapered annular cone bushing  370 . The cone bushings  370  have tapered exterior surfaces. Interior surfaces of the cone bushings  370  may be treated to increase friction and prevent slippage with the surface of the pin such that the pin rotates in concert with the attached lugs A and B. The cone bushings  370  are oriented with the thicker end of the taper inboard. The thicker end has a circumferentially extending notch  372  that is configured and sized to receive a portion of spacer  320  when the bushing connection system is assembled, but is able to slip over the surface of spacer  320 . An annular cup bushing  360  is located on each of the cone bushings  370 . The cup bushings  360  have interior surfaces that are tapered at a counter-taper to that of the outer surfaces of the cone bushings  370 . During torqueing of the fastener  390 , as in other embodiments described above, the surface  384  of cap  380  functions as a compression boss urging all the components of the bushing assembly  300  axially together such that the complimentary counter-tapers of the cone and cup bushings  360  and  370  become engaged and thereby correct for any component misalignment. The cup bushing (similar to the above described outer cup bushings) may have an expansion joint to allow its diameter to expand during assembly and thereby urge against the bore of an attached lug. The angle of taper a of the bushings may range from 5 to 25, and desirably 15 degrees, but may be more or less. The outer surface  365  of each cup bushing  360  may be provided with grooves  362 , depicted as axial and radial grooves in this example. A pair of outer spacers  326  are located outboard of each of the cup bearings  360 . These annular spacers  326  have an inner diameter less than that of the compression boss  384 , but greater than that of pin  310  such that it does not interface with cone bearing  370 . As such, the spacer  326  is sized and configured to receive the leading edge  384  of the retainer cap  380 , when the assembly  300  is urged together by torqueing the fastener  390 , and to transfer forces axially along the assembly of components. 
         [0043]    A retainer cap  380 , like that described for the above exemplary embodiment, or one of a different design, may be fitted onto ends  314  of pin  310 . During torqueing, the inner surfaces  384  of caps  380  function as a compression boss urging all the components of the bushing assembly  300  axially toward the axis V. As explained above, the retainer cap  380  may be gripped by a wrench or other tool at opposed flats  388  such that a fastener  390  can be threaded into end hole  312  and the head  394  of the fastener is drawn into the countersunk bore  387  of the retainer cap. The offset c in the threaded bore  312  permits the bushing assembly  300  to be immobilized in such a manner. Torqueing (and urging) is continued until the rotary bushing assembly  300  is fully aligned and secure in place. At that stage, a locking pin  395  is inserted through a radially extending bore in cap  380  (not shown) and through a bore  398  in fastener  390 , when these bores are lined up into registration with each other. 
         [0044]    A fourth exemplary embodiment  400  of the misalignment-compensating rotary bushing connection system is illustrated in  FIGS. 9 ,  10 , and  11 A- 11 E. Reference to “inboard” and “outboard” with regard to this embodiment refers to proximity to the spacer  420 . 
         [0045]    The fourth embodiment  400  compensates for any misalignment and provides appropriate alignment between the three lugs, A, B and C. Lugs A and B are immobile with respect to pin  410 , while lug C rotates about pin  410 . The central pin  410  has a first section  416  and a second section  418 . Section  416  is cylindrical, and section  418  is frusto-conical, tapered at an angle β, with a larger diameter end being outboard. At the intersection of the first and second sections  416  and  418  is a ledge of radial depth l. As a result of the depth l of the ledge, thrust bearing  415  avoids contact with pin  410  at that point, as explained later. At the opposite end to end  415  of pin  410 , there is a central boss  414  of smaller diameter than pin section  416 , and that has external threading. In this embodiment, the central boss  414  of the pin extends farther out than the peripheral ends  412  of the pin. However, in alternate embodiments, the peripheral ends  412  may extend beyond the central boss  414  or to the same length as the central boss  414 . The threaded boss  414  is used in assembling the connection system, as explained here below. 
         [0046]    Approximately at the axial center of the exemplary embodiment is a spacer  420 . The spacer is flanked by a pair of sleeve bearings  430  that are located on the pin  410  and that rotate about the pin. 
         [0047]    An annular inner cone bushing  440  is located on the outer surface of each of the sleeve bearings  430 , and moves with the sleeve bearing. The inner surface of cone bushing  440  is substantially cylindrical allowing it to fit in complementary engagement onto the outer cylindrical surface of sleeve bearing  430 , such that the two move in concert. The outer surface of the inner cone bushing  440  is frusto-conical and tapers along its axial length, from one side to the other side. Thus, the inner cone bushing  440  has a greater thickness on one side than on the axially opposite side. Inner cone bushing  440  has a taper of α degrees, which may vary from 5 to 25, and desirably 15 degrees, in some examples, but may be more or less. Inner cup bushing  450  has a cylindrical outer surface  455  and an inner surface having a taper complementary to that of the outer surface of inner cone bushing  440 . Thus, it has an inner taper of α degrees. Outer surface  455  may be equipped with grooves  452  to minimize slippage across the surface. During assembly, as explained later, the complementary counter-tapers of inner cone bushing  440  and inner cup bushing  450  are urged into engagement and the outer diameter expands and urges against the bore of attached lug C. Thereby, this engagement facilitates correcting for any misalignment by re-aligning components. 
         [0048]    On each of the outboard sides of the inner cone bushings  440  is a thrust bearing  415 , that has a substantially annular shape and that extends around the outer circumference of the first section  416  of pin  410 . Each thrust bearing has a notch that runs all around one of its circular side surfaces, and that is configured and sized to receive therein a tapered end of an outer cone bushing  470 , and such that a smooth outboard face of the bearing slides against outer cup bushings  460  and  460 ′. 
         [0049]    An annular frusto-conical outer cone bushing  470  is located on the outer surface of the first section  416  of pin  410 , and has an inner surface that may maximize friction and prevent slippage with the pin. The outer cone bushing  470  has an inner surface that is cylindrical and sized and configured to fit onto the outer surface of pin  410 . The outer surface of outer cone bushing  470  has a taper at an angle of β, of between 5 and 25 degrees, desirably 15 degrees, but may be more or less. The outer surface  475  is oriented with the thicker end of the taper outboard. The outer cone bushing  470  may include a series of slots extending through the thickness of the bushing and alternating by extending axially from one end, then from the other end of the bushing. The slots are shorter than the axial length of the bushing. 
         [0050]    An annular outer cup bushing  460  is located on the outer cone bushing  470 . The outer cup bushing  460  has a cylindrical outer surface  450  and an inner surface that tapers at an angle α that is complementary to the outer surface taper of outer cone bushing  470 . The outer cup bushing  460  may have an expansion joint to permit its diameter to expand during assembly. 
         [0051]    Another annular outer cup bushing  460 ′ is located on the outer surface of section  418  of the pin  410 . The outer surface of pin section  418  may be grooved, and is tapered at an angle α. The inner surface of outer cup bushing  460 ′ matches that taper angle such that the two surfaces are in complementary engagement when the cup bushing  460 ′ is located on the pin section  418 . Taper angle β may vary from 5 to 25 degrees, desirably 15 degrees, but may be more or less. The outer surface  465 ′ of the cup bushing  460 ′ may be provided with grooves  462 ′, as illustrated, to minimize slippage with an attached lug. The outer cup bushing  460 ′ may have an expansion joint to permit its diameter to expand during assembly. 
         [0052]      FIGS. 11A-11E  illustrate in more detail the steps of assembling the fourth embodiment  400 , in particular assembly of retainer cap  480 . First, inboard components are located onto pin  410  starting with the outer cup busing  460 ′ and ending with outer cup bushing  460  and outer cone bushing  470  as shown in  FIG. 10 ). These inboard components have been omitted from  FIGS. 11A-E  for clarity. Next, a cotter pin  495  is inserted into a bore  490  in the central boss  414  of pin  410  as shown by the arrow in  FIG. 11A . The ends of the cotter pin  495  are bent at a 90 degree angle as shown in  FIG. 11B  by the arrows. Alternatively, the inboard components may be located onto the pin after the cotter pin has been bent. Next, a retainer cap  480  having an inner-threaded, central-through hole is threaded onto the central boss  414  of pin  410  (see  FIG. 11C ). The pair of ends of the cotter pin  495  extends outward through the central hole in retainer cap  380 . 
         [0053]    During assembly, the retainer cap  480  is initially partially-threaded onto the boss  414  as is explained in more detail below. This can be done by hand. Then, the untightened, misalignment-compensation system  400  may be inserted into lugs A, B, and C. Then retainer cap  480  may be fully tightened by inserting a fastening tool into socket  498  of central boss  414  of the pin to torque pin  410  while retainer cap  480  may be gripped immovably using a tool (e.g., a spanner wrench) that inserts into holes  482  (see  FIG. 11D ). Alternatively, pin  410  may be gripped immovably while retainer cap  480  is torqued. During this torqueing, the peripheral inner surface  486  of the retainer cap  480  acts as a compression boss to push axially against outer cone bushing  470  (see  FIG. 10 ). This axial pushing urges the complementary tapers of the assembled cone-and-cup bushings into alignment, which cause their exterior diameters to expand and urge against the bores of the lugs A, B, and C. Once embodiment has been torqued such that the assembly is complete, the ends of cotter pin  495  are bent backward at 90 degrees to fit within any pair of opposed slots  487  on the exterior surface of retainer cap  480  as shown by the arrow in  FIG. 11E . Thus, retainer cap  480 , which is threaded to central boss  414  of the pin, is secured and neither can rotate independently of the other. That is, retainer cap  480  is threaded to pin  410  and cannot be removed from the pin without first straightening the ends of cotter pin  495  and unthreading retainer cap  480 . 
         [0054]      FIGS. 12A-12D  depict an exemplary method for assembling an exemplary embodiment  800  of the rotary misalignment-compensation bushing connection system. Exemplary embodiment  800  depicted in  FIGS. 12A-12D  is substantially identical to the second embodiment  200  disclosed above. A fastening tool  850  is inserted into socket  825  of exemplary embodiment  800  and is used to partially fasten the exemplary embodiment (see  FIG. 12A ). In this position, the components of exemplary embodiment  800  are loosely engaged and have their smallest exterior diameter. It is clear that the largest diameter of embodiment  800  (when not fully-fastened) must be less than the smallest bore of the lugs when the exemplary embodiment  800  is being inserted. Next, the partially-tightened embodiment  800  is inserted into a series of lugs, A, B, and C, as illustrated in  FIG. 12B . Once embodiment  800  is approximately in place, it may be fully-torqued from one side using a fastening tool  850  to torque the socket  825  while another tool (e.g., a wrench) engages the pair of spaced flats  827  of the retainer cap of the exemplary embodiment  800  (see  FIG. 12C ). Alternatively, in lieu of partially-tightening and inserting, the pin of embodiment  800  may first be inserted into the bore of the lugs, then the components may be placed on to the pin, and then the embodiment may be fully-tightened. Because the threaded hole of the pin of exemplary embodiment  800  is offset from center by a distance c (see  FIG. 2 ), the pin may be rotationally immobilized by immobilizing the retainer cap using a tool as shown in  FIG. 12C . As exemplary embodiment  800  is torqued, small errors in the alignment of the lugs (even up to ⅛ th  inches in assemblies with pin diameters up to 4 inches, and more in larger sizes) are corrected as the various components are urged into their proper locations. During torqueing of the socket, the components of exemplary embodiment  800  are urged together and the diameter of the embodiment  800  expands slightly, as axial components are brought into overlapping alignment and complementary tapers are engaged. This radial expansion is sufficient for the appropriate surfaces of embodiment  800  to engage the surfaces of the bores of the lugs and prevent the exemplary embodiment and the lugs from disengaging. Finally, a locking pin  895  may be inserted to lock the embodiment (see  FIG. 12D ). Similarly, the other embodiments of the rotary misalignment-compensation bushing connection system disclosed and claimed herein may be assembled and engaged as is apparent to one of ordinary skill in the art. 
         [0055]    While examples of embodiments of the rotary misalignment-compensation bushing connection system have been presented and described in text and, in some examples, also by way of illustration, it will be appreciated that various changes and modifications may be made in the described rotary misalignment-compensation bushing connection system and its components without departing from the scope of the invention, which is set forth in, and only limited by, the scope of the appended patent claims, as properly interpreted and construed.

Technology Category: 4