Abstract:
A dual bushing installation kit includes a first metal bushing and a second metal bushing. The first metal bushing can include a first body having first and second ends. The first and second ends are connected by a first outer surface having a first outer circumference and a first inner surface having a first inner circumference. The second metal bushing is defined by a second body having first and second ends. The first and second ends are connected by a second outer surface having a second outer circumference and a second inner surface having a second inner circumference. The second outer circumference is dimensioned to be substantially conforming with the first inner circumference such that the second bushing is closely receivable by a first opening of the first bushing. Both the second outer circumference and the first inner circumference can be expanded in an outwardly radial direction.

Description:
RELATED APPLICATION 
     This application is a divisional of U.S. patent application Ser. No. 09/603,857, filed on Jun. 26, 2000, now pending, which application is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to the provision and installation of tubular bushings in openings in work members. More particularly, it relates to the provision of bushings having flanges at both ends and to methods of radially expanding tubular portions of the bushings to create a tight interference fit between them and the openings in the work member. 
     BACKGROUND OF THE INVENTION 
     It is known to secure a bushing within an opening in a structural wall by positioning the bushing within the opening, holding it in place, and then forcing an expansion mandrel through the bushing to radially expand the bushing into an interference fit with the opening. 
     U.S. Pat. No. 4,809,420, granted Mar. 7, 1989, to Michael A. Landy, Todd L. Thompson and Larry I. Wiemann, and U.S. Pat. No. 5,433,100, granted Jul. 18, 1995, to Eric T. Easterbrook, Todd L. Thompson and Mark R. Weiss, both disclose the use of a mandrel alone for installing bushings in openings in a work member. 
     U.S. Pat. No. 4,557,033, granted Dec. 10, 1985, to Robert L. Champoux, discloses using a mandrel alone for cold expanding an opening in a work member for the purpose of introducing fatigue life enhancing compressive residual stresses in the work member immediately around the opening in the work member. 
     U.S. Pat. No. 5,103,548, granted Apr. 14, 1992, to Leonard F. Reid and Roger T. Dolstad discloses the use of a mandrel and a split sleeve together for installing a tubular bushing in an opening in a work member and at the same time introducing fatigue life enhancing compressive residual stresses in the work member. 
     The contents of U.S. Pat. Nos. 4,557,033; 4,809,420 and 5,103,548 are hereby incorporated herein by this specific reference. 
     U.S. Pat. No. 3,835,688, granted Sep. 17, 1974, to John O. King, Jr. and U.S. Pat. No. 3,949,535, granted Apr. 13, 1976, also to John O. King, Jr. each discloses a method of both installing a seamless tubular member in openings in two members to be joined and expanding the material immediately surrounding the openings for the purposes of fatigue life enhancement. The seamless tubular members disclosed by these patents have a flange at one end that contacts the side of one of the members from which the tubular member is inserted. U.S. Pat. No. 3,949,535 discloses providing a flare on the end of the sleeve opposite the flange to assist in retaining the sleeve in the opening in the workpiece. This flare is formed by the movement of the mandrel through the sleeve and it requires a particular end construction of the sleeve. 
     Thus, it is known to provide a bushing with a radial flange at one of its ends. There is a need for providing a bushing that has a radial flange at each of its ends. For example, when bushings are used in a lug or clevis, there is a potential of face-to-face contact between the joined parts. Flanges on both ends of the bushing would protect the face-to-fact contact of the parent material in which the bushing has been installed. The flanges could be used to react a load applied to the lug or clevis along a line parallel to the bore of the lug or clevis. For example, in a landing gear lug on an aircraft, the lug might see a load transmitted to the pin through the lug perpendicular to the axis of the bore, due to the weight of the aircraft. However, it could also see an axial load due to the fore and aft loading of the lug. A second flange on a bushing could also be used to provide a surface on which a nut and washer may seat when a threaded pin is used to retain the pin in the joint. The principal object of the present invention is to provide tubular bushings having flanges at both of their ends. Another object is to provide methods of making and installing tubular bushings that have flanges at both ends. 
     U.S. Pat. Nos. 3,835,688 and 3,949,535, and the other above-identified patents should be carefully considered for the purpose of putting the present invention into proper prospective relative to the prior art. 
     BRIEF SUMMARY OF THE INVENTION 
     According to the present invention, a workpiece is provided that includes first and second sides and a cylindrical opening extending through it between the two sides. A bushing is provided that includes a tubular center portion that is placed within the cylindrical opening. A first radial flange is connected to the tubular center portion of the bushing on the first side of the work member. This flange extends radially outwardly from the tubular center portion of the bushing, in contact with the first side of the work member. A second radial flange is connected to the tubular center portion of the bushing on the second side of the work member. This second radial bushing extends radially outwardly from the tubular center portion of the bushing, in contact with the second side of the work member. The tubular center portion of the bushing is radially expanded in the cylindrical opening to such an extend that it makes a tight interference fit within the opening and connects the bushing to the work member. 
     According to one aspect of the invention, the tubular center portion of the bushing is a single continuous tubular member that is connected at one end to the first flange and which includes a second end portion that extends axially outwardly beyond the second side of the work member. The second flange is a radial member having a center opening in which the projecting end portion of the tubular member is received. The tubular member is radially expanded in the center opening of the second flange to such an extent that it makes a tight interference fit with the opening in the second flange and connects the second flange to the tubular member. 
     According to another aspect of the invention, the bushing is composed of a first bushing part that includes the first flange and a first tubular member that is connected to the first flange, and a second bushing part that includes the second flange and a second tubular member that is connected to the second flange. The two tubular members together form at least a part of the central portion of the bushing. The first tubular member may extend substantially completely through the opening and the second tubular member may be positioned in the first tubular member and extends substantially completely through it. The two tubular members are concentric. The radial expansion connects the first tubular member to the sidewall of the opening and connects the second tubular member to the first tubular member. 
     According to another aspect of the invention, the first tubular member extends axially from a first flange into and partially through the cylindrical opening in the work member. The second tubular member extends from the second flange into and partially through the opening in the work member, coaxial with the first tubular member. The outside diameters of the tubular members may be close in size to the inside diameter of the opening, so that when radially expanded, the two tubular members make a tight interference fit with the opening in the work member. Or, the first and second tubular members may be surrounded by a third tubular member, in which case the radial expansion connects the first tubular member to the sidewall of the opening in the work member and connects the second and third tubular members of the bushing parts to the first tubular member. That is, the third tubular member makes a tight interference fit with the cylindrical opening in the work member and the second and third tubular members make tight interference fits with the first tubular member. 
     The present invention also includes methods for installing double flanged bushings in openings in work members. According to a first method aspect of the invention, a work member is provided that has a first side and an opposite second side. A cylindrical through opening is provided in the work member, extending from the first side to the second side. A first bushing part is provided that has a tubular section and a radial flange section at one end of the tubular section. The tubular section has an outside diameter substantially corresponding to the diameter of the through opening in the work member. The tubular section of the first bushing part is inserted into and through the opening in the work member, from the first side of the work member. The first bushing part is moved axially to place its flanged section against the first side of the work member. The tubular section of the first bushing part is of such a length that when the flange section is against the first side of the work member, the tubular section has an end portion opposite the flanged section that projects axially outwardly of the opening, beyond the second side of the work member. A second bushing part includes a center opening that is sized to receive the projecting end portion of the tubular section of the first bushing part. The second busing part extends radially outwardly from this center opening. The second bushing part is positioned on the projecting end portion of the tubular section of the first bushing part and is moved substantially against the second side of the work member. Then, the tubular section of the first bushing member is radially and circumferentially expanded an amount sufficient to provide a tight interference fit between it and the through opening in the work member and between its projecting end portion and the opening in the second bushing part. This connects the first bushing part to the work member and connects the second bushing part to the projecting end portion of the tubular section of the first bushing part, such that the second bushing part functions as a second flange at the end of the first bushing part that is opposite the flange section of the first bushing part. 
     The tubular section of the bushing part may be radially expanded an amount sufficient to also introduce fatigue life enhancing compressive residual stresses in the work member immediately around the opening in the work member. 
     The cold expansion of the tubular section, both for connecting it to the work member and the second bushing part, and for introducing fatigue life enhancing compressive residual stresses in the work member, may be accomplished by moving a tapered mandrel axially through the first bushing part, and providing the mandrel with a large diameter end portion that is sized such that when it moves through the tubular section of the first bushing part it will radially expand the tubular section of the first bushing part to the extent needed. 
     According to another aspect of the invention, a first bushing part is provided that has a tubular section and a radial flange section at one end of its tubular section. The tubular section of the first bushing part is provided with an outside diameter substantially corresponding to the diameter of the opening in the work member. The second bushing part is provided that has a tubular section and a radial flange section at one end of its tubular section. The tubular section of the second bushing part is provided with an outside diameter substantially corresponding to the inside diameter of the tubular section of the first bushing part. The tubular section of the first bushing part is moved into and through the opening in the work member, from the first side of the work member. It is moved axially until its flange section is substantially against the first side of the work member. Then, the tubular section of the second bushing part is inserted into the tubular section of the first bushing part, from the second side of the work member. The second bushing part is then moved axially to place its flange section substantially against the second side of the work member. The tubular sections of the first and second bushing parts are radially and circumferentially expanded together, an amount sufficient to provide a tight interference fit of the tubular section of the second bushing part in the tubular section of the first bushing part, and a tight interference fit of the tubular section of the first bushing part in the opening in the work member. They also may be radially and circumferentially expanded an amount sufficient to also introduce fatigue life enhancing compressive residual stresses in the work member immediately around the opening in the work member. 
     According to a further aspect of the invention, a first bushing part is provided that has a tubular section and a radial flange at one end of the tubular section. The tubular section has an outside diameter substantially corresponding to the diameter of the opening in the work member and a length that is only a portion of the length of the opening in the work member. A second bushing part is provided that has a tubular section and a radial flange at one end of the tubular section. This tubular section also has an outside diameter substantially corresponding to the diameter of the opening in the work member and a length that is less than the length of the opening in the work member. The tubular section of the first bushing part is inserted into the opening in the work member, from the first side of the work member, and is moved axially to place the flange section of the first bushing part against the first side of the work member. The tubular section of the second bushing part is inserted into the opening in the work member, from the second side of the work member, and is moved axially until the flange section of the second bushing part is against the second side of the work member. Then, the two tubular sections are radially and circumferentially expanded an amount sufficient to provide a tight interference fit between them and the opening in the work member, for connecting the first and second bushing parts to the work member. The cold expansion may also be sufficient to introduce fatigue life enhancing compressive residual stresses in the work member immediately around a through opening in the work member. 
     According to yet another aspect of the invention, a tubular first bushing part is provided that has an outside diameter substantially corresponding to the diameter of the opening in the work member and a length substantially corresponding to the length of the opening in the work member. A second bushing part is provided that has a tubular section and a radial flange section at one end of the tubular section. The tubular section of the second bushing part has an outside diameter substantially corresponding to the inside diameter of the first bushing part and a length that is a portion of the length of the first bushing part. A third bushing part is provided. It has a tubular section and a radial flange section at one end of the tubular section. The tubular section of the third bushing part also has an outside diameter substantially conforming to the inside diameter of the first bushing part and a length that is a portion of the length of the first bushing part. The first bushing part is inserted into the opening in the work member. Then, the tubular section of the second bushing part is inserted into the first bushing part, from the first side of the work member. The second bushing part is moved axially until its flange section is against the first side of the work member. Next, the tubular section of the third bushing part is inserted into the first bushing part, from the second side of the work member. The third bushing part is moved axially until its flange section is against the second side of the work member. Then, the first bushing part and the tubular sections of the second and third bushing parts are radially expanded together an amount sufficient to provide a tight interference fit between the first bushing part and the opening in the work member and between the tubular sections of the second and third bushing parts and the first bushing part. The bushing parts are expanded circumferentially an amount sufficient to connect the second and third bushing parts to the first bushing part and connect the first bushing part to the work member. They also may be radially expanded an amount sufficient to introduce fatigue life enhancing compressive residual stresses in the work member substantially surrounding the through opening in the work member. 
     Other objects, advantages and features of the invention will become apparent from the description of the best mode set forth below, from the drawings, from the claims and from the principles that are embodied in the specific structures that are illustrated and described. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       Like reference numerals are used to designate like parts throughout the several views of the drawing, and: 
         FIG. 1  is an exploded pictorial view of prior art tooling for installing a tubular bushing in an opening in a work member; 
         FIG. 2  is a pictorial view in longitudinal section of two flanged bushing that forms a part of the present invention; 
         FIG. 3  is a view like  FIG. 2 , showing a second two flanged bushing that is a part of the present invention; 
         FIG. 4  is a view like  FIGS. 2 and 3 , showing a third two flanged bushing that is a part of the invention; 
         FIG. 5  is a view like  FIGS. 2-4  showing a fourth two flanged bushing that is a part of the present invention; 
         FIG. 6  is a fragmentary sectional view showing the tooling of  FIG. 1  being used to install a bushing of the type shown by  FIG. 2 , such view showing a first bushing part having a tubular portion that is in an opening in the wall and a radial flange at one end that is against a first side of the wall, and a second bushing part in the form of an annular member surrounding an end part of the tubular portion of the first bushing part that projects outwardly of the opening, beyond the second side of the work member, and such view showing a mandrel in an extended position within the tubular portion of the first bushing part; 
         FIG. 7  is a view like  FIG. 6  but showing the mandrel being retracted and showing an enlarged end portion of the mandrel radially expanding the tubular portion of the first bushing part as it moves through it; 
         FIG. 8  is a view like  FIGS. 6 and 7 , showing the mandrel in a retracted position and the nose piece of the puller tool being moved away from the installed bushing; 
         FIG. 9  is a view like  FIG. 7 , but showing the tooling being used to install a bushing of the type shown by  FIG. 3 ; 
         FIG. 10  is a view like  FIGS. 7 and 9 , but showing the tooling being used to install a bushing of the type shown by  FIG. 4 ; 
         FIG. 11  is a view like  FIGS. 7 ,  9  and  10  but showing the tooling being used to install a bushing of the type shown by  FIG. 5 ; 
         FIG. 12  is a longitudinal sectional view showing a bushing of the type shown in  FIG. 2  installed in an opening in a work member; 
         FIG. 13  is a view like  FIG. 12 , but showing a bushing of the type shown by  FIG. 3 ; 
         FIG. 14  is a view like  FIGS. 12 and 13 , but showing a bushing of a type shown by  FIG. 4 ; 
         FIG. 15  is a view like  FIGS. 12-14 , but showing a bushing of the type shown by  FIG. 5 ; 
         FIG. 16  is an enlarged scale fragmentary view of an upper central portion of  FIG. 15 , such view showing that the bushing end parts may have concentric lapping portions where they meet; and 
         FIG. 17  is a view like  FIG. 16 , but of the upper central region of  FIG. 14 , such view showing that the end parts of the bushing can have concentric lapping portions where they meet, the same as shown in  FIG. 16 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows prior art tooling for installing a prior art bushing  10 . The tooling includes a puller  12  that includes a nose piece  14  having a forward end surface  16  and a mandrel receiving opening  18 . In this system, the mandrel M includes a small diameter inner end portion  20  that extends into the puller  12  via the opening  18 . It further includes a bushing receiving central portion  22  and an enlarged end portion  24 . In this system, it is necessary to slide the bushing  10  onto the mandrel from the smaller end of the mandrel M and then insert the mandrel into the puller and connect it to a piston that is inside the puller  12 . This installation of the mandrel M is shown by the aforementioned U.S. Pat. Nos. 4,809,420 and 5,433,100. Reference is made to U.S. Pat. No. 5,433,100 for a more complete description and disclosure of the mandrel and puller assembly. 
       FIGS. 2 ,  6 - 8  and  12  disclose a first embodiment of the double flanged bushings of the present invention. This bushing  25  is composed of a first bushing part  26  and a second bushing part  28 . Bushing part  26  comprises a tubular section  30  and a radial flange section  32 . Flange section  32  is connected to one end of the tubular section  30 . Tubular section  26  extends axially and radial flange section  32  extends radially. Bushing part  28  is a radial member  34  that includes a center opening  36 . Preferably, but not necessarily, the radial length of member  34  substantially equals the radial length of flange section  32  measured from the outside diameter of the tubular section  30 . 
     A through opening  38  is provided in a work member  40  to receive the bushing  25 . An initial opening  38  is formed by use of a drill. The drilled opening is then reamed to provide a desired starting diameter. After reaming, the starting diameter is verified by use of a hole-diameter gauge. If the opening  38  is oversized, it must be reworked to provide it with a proper slightly larger diameter. An appropriate primer may be applied to the opening  38 . 
       FIGS. 6-8  show the bushing  28  in the process of being installed into the opening  38  in a work member  40 , shown in the form of a structural wall  40 . The tubular section  30  of bushing part  26  has an outside diameter substantially corresponding to the diameter of opening  38 . Tubular section  30  has a length that is slightly longer than the length of the opening  38 , so as to provide it with an end portion  42  that projects axially outwardly from the second wall  44  of the member  40  when the flange  32  is against the first wall  46  of the member  40 . The opening  36  in member  34  has a diameter substantially corresponding to the outside diameter of end part tubular section  30 . End portion  42  has a length substantially corresponding to the thickness of the member  34 . 
     As shown by  FIG. 6 , the tubular section  30  of member  26  is inserted into the opening  38 , from the first side of the member  40 . It is moved axially through the opening  38  until the radial flange  32  contacts sidewall  48 . When this happens, the end portion  42  of tubular section  30  projects axially outwardly of the opening  30 , beyond the second surface  44 . It may be desirable to apply a sealant to the inwardly side of the flange  32 . Next, the second bushing part  28  is installed on this end portion  42 . Bushing part  28  is moved towards the end portion  42  until the end portion  42  is inside the opening  36 . It might be desirable to apply a sealant to the inward surface of bushing part  28 . Then, the mandrel M is inserted through the tubular section  30 , from the first side of the member  40 . Its inner end portion  20  is connected to a piston inside of the puller  12 , such as is disclosed in U.S. Pat. No. 5,433,100, with reference to FIGS. 20 and 21 of that patent. Following connection of the mandrel M to the puller  12 , mandrel section  22  is inside the tubular section  30  and the enlarged end portion  24  of the mandrel M is spaced from the first side  46  of member  40 . The surface  16  on nose piece  14  is positioned against member  34  such that member  34  is clamped between surface  16  and surface  44 . Then, the puller  12  is operated to retract the mandrel M and pull it through the tubular section  30 . 
       FIG. 7  shows the mandrel M in the process of being retracted and shows its enlarged end portion  24  in the process of stretching and enlarging tubular section  30  both radially and circumferentially as it moves through tubular section  30 . During this movement, the drag of the mandrel head  24  on the tubular section  30  pulls the flange  32  of bushing part  26  tight against surface  26 . A reaction to the pulling force moves the nose piece  14  forwardly to place its forward surface  16  into tight contact with the radial member  34 . Thus, movement of the mandrel M pulls flange  32  into tight contact with surface  46  and pushes the member  34  into tight contact with surface  44 . At the same time, the tubular section  30  is expanded to make a tight interference fit with the sidewall of opening  38 . As the enlarged portion  22  of the mandrel M moves through the end portion  42  of tubular section  38 , it radially and circumferentially expands the end portion  42 , causing a tight interference fit between it and the sidewall of opening  36  in member  34 . 
       FIG. 8  shows the mandrel M fully retracted within the nose piece  14  of the puller  12 . The end portion  25  of the mandrel M has been moved entirely through the tubular section  30 . As a result, the puller  12  and mandrel M are freely movable away from the installed bushing  26 ,  28 .  FIG. 8  shows an axial space  48  starting to form between side surface  44  of member  40  and end surface  16  of nose piece  14 . It further shows the bushing parts  26 ,  28  installed within the opening  18 . The installed bushing parts  26 ,  28 , are also shown in  FIG. 12 , with the puller  12  having been moved away from the work member  40 . 
     Following its installation, the inside surface of the tubular section  30  might be slightly tapered. In that case the opening in tubular section  30  may be reamed to a desired inside diameter and to remove lubricant residual. The lubricant residual may be present because it is common practice to use a lubricant between a mandrel M and a bushing through which the mandrel M is moved. 
     Movement of the mandrel M through the bushing  25  expands the tubular section  30  beyond elastic expansion and into plastic expansion. That is, the material is expanded a sufficient amount that it will assume and retain a new diameter. 
       FIGS. 3 ,  9  and  13  show another form of two part bushing  50 . A first bushing part  52  has a tubular section  54  and a radial flange section  56  at one end of the tubular section  54 . As shown by  FIGS. 9 and 13 , the tubular section  54  has an outside diameter substantially conforming to the opening  38  in the work member  40 . Tubular section  54  has a length measured from the inside of flange section  56  to its opposite end that substantially corresponds to the length of the opening  38 . Bushing part  58  has a tubular section  60  and a radial flange section  62  connected to one end of the tubular section  60 . Tubular section  60  has an outside diameter substantially conforming to the inside diameter of tubular section  54 . It has a length substantially conforming to the length of the opening in tubular section  54 . 
     The opening  38  is formed and prepared in the manner described above. Primer may be applied to the inside of the opening  38 . Sealant may be applied to the inside surfaces of the flanges  56 ,  62  of the bushing  50 . The bushing  50  is installed in the following manner. The tubular section  54  of bushing part  52  is inserted into the opening  38  in the work member  40 , from the first side of the work member  40 . It is then pushed axially inwardly until the inner surface of flange section  56  contacts the side surface  46  on the work member  40 . Then, the tubular section  60  of the bushing part  58  is installed into the opening in bushing section  54 , from the second side of the work member. It is moved inwardly until the inner surface of flange section  62  contacts the sidewall  44  of work member  40 . Next, as shown by  FIG. 9 , the mandrel M and puller  12  are used to radially and circumferentially expand the two tubular sections  54 ,  60 . The mandrel M is installed in the manner described above in connection with  FIGS. 6-8  and a lubricant is used between it and the bushing  50 . It is then pulled axially into the puller  12  so as to move its enlarged end portion  24  axially through tubular section  60 , as shown in  FIG. 9 . As it moves, the mandrel head  24  radially and circumferentially expands both tubular section  60  and tubular section  54 . This expansion makes a tight interference fit between tubular section  54  and the sidewall of opening  38  and makes a tight interference fit of tubular section  60  within tubular section  54 . This connects tubular portion  54  to the sidewall of opening  38  and connects tubular portion  60  to tubular portion  54 . As can be seen from  FIG. 9 , movement of the mandrel M through the tubular section  54  applies a drag force on the bushing part  52  that pulls the flange section  56  into tight contact with the wall  46  of work member  40 . The end surface  16  of nose piece  14  is pressed by reaction forces tightly against flange section  62 , moving flange section  62  into tight engagement with sidewall  44  of work member  40 . 
       FIGS. 4 ,  10  and  14  disclose a third embodiment of the bushing. This bushing  66  has three parts. A tubular first bushing part  68  has an outside diameter and a length that correspond to the diameter and length of opening  38  in work member  40 . The second bushing part  70  has a tubular section  72  and a radial flange section  74  at one end of the tubular section  72 . It has an outside diameter substantially conforming to the inside diameter of bushing part  68 . It has a length that is shorter than the opening  38  in work member  40 . The third bushing part  76  has a tubular section  78  and a radial flange section  80  at one end of the tubular section  78 . Preferably, bushing parts  70 ,  76  are alike. Preferably also, the tubular sections  72 ,  78  are substantially the length of tubular section  68  and the opening  38  in the work member  40 . 
     Bushing  66  is installed in the following manner. Firstly, bushing part  68  is placed in the opening  38  in work member  40 . Then, tubular section  72  of bushing part  70  is inserted into the bushing part  68  from the first side of the work member  40 . Bushing part  76  is inserted into the bushing part  68  from the opposite side of the work member. The bushing parts  70 ,  76  are moved toward each other until radial flange  74  is substantially against side surface  46  and radial flange  80  is substantially against side surface  44 . Then, the mandrel M and the puller  12  are used in a manner described above in connection with the first two embodiments. Axial movement of the enlarged end portion  24  of the mandrel M through the bushing parts  68 ,  70  radially and circumferentially expands tubular sections  72 ,  78 ,  68 . As a result, bushing part  68  is moved into a tight interference fit with the sidewall of opening  38 . Tubular sections  72 ,  78  and bushing part  70 ,  78  are moved into a tight interference fit with bushing part  68 . Flange section  74  is pulled into tight contact with side surface  46  and flange section  80  is pushed into tight contact with side surface  44 . The expansion connects bushing part  68  to the side surface of opening  38  and connects tubular sections  72 ,  78  of bushing parts  70 ,  76  to bushing part  68 . Tubular sections  72 ,  78  may have concentric overlapping portions where they meet. This is shown by  FIG. 17 . End portion  72 ′ is shown to concentrically surround end portion  78 ′. 
       FIGS. 5 ,  8  and  15  show a fourth embodiment of the bushing. This bushing  86  is composed of two bushing parts  88 ,  90  which are preferably identical in construction. Bushing part  88  has a tubular section  92  and a radial flange section  94  that is connected to one end of the tubular section  92 . Bushing part  90  has a tubular section  96  and a radial flange section  98  that is connected to one end of the tubular section  96 . The outside diameters of the tubular sections  92 ,  98  substantially conform to the diameter of the opening  38  in the work member  40 . The tubular sections  92 ,  96  are both shorter than the opening  38  but, preferably, their combined lengths substantially equal the length of the opening  38  ( FIG. 15 ). The tubular sections  92 ,  96  may have concentric end portions that form a lap joint where they meet. End part  92 ′ concentrically surrounds end part  96 ′. 
     The bushing  86  is installed in the following manner. The tubular sections  92 ,  96  are either installed separately or together into the opening  38  from opposite sides of the work member. The bushing parts  86 ,  90  are moved axially together until flange section  94  substantially contacts sidewall  46  and flange section  98  substantially contacts side surface  44 . Then, the mandrel  20  and the puller  12  are used in the manner described above for radially and circumferentially expanding the tubular sections  92 ,  98  in the opening  38 . As previously described, axial movement of the mandrel  20  through the tubular sections of the bushing acts to pull flange section  94  against sidewall  46  and push flange section  98  against sidewall  44 . 
     Preferably, the installation of bushings  50 ,  66 ,  86  includes radially and circumferentially expanding the tubular sections of the bushing parts an amount sufficient to introduce fatigue life enhancing compressive residual stresses in the work member immediately around the opening  38  in the work member  40 . 
     The various bushing parts that have been described can be made from any suitable metal that has to date been used for making bushings and from new materials that might be developed for use in making bushings, or for use in making other structures but suitable for use in making bushings. Typical examples are bronze, bronze alloys, brass, brass alloys, aluminum, aluminum-nickel-bronze, copper beryllium, stainless steels and Inconel and other high temperature engine alloys, alloys, and carbon steels, etc. The work member  40  may be a structural wall or it may be some other structural member. It may be made from metal or composite materials. 
     The illustrated embodiments are only examples of the present invention and, therefore, are non-limitive. It is to be understood that many changes in the particular structure, materials and features of the invention may be made without departing from the spirit and scope of the invention. Therefore, it is my intention that my patent rights not be limited by the particular embodiments illustrated and described herein, but rather determined by the following claims, interpreted according to accepted doctrines of claim interpretation, including use of the doctrine of equivalents and reversal of parts.