Patent Publication Number: US-8117885-B2

Title: Mandrel with retention sleeve and methods of using the same

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 11/824,559 filed Jun. 29, 2007, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 60/818,133 filed Jun. 29, 2006. Each of these applications is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     1. Field of the Disclosure 
     This disclosure generally relates to self-aligning tools with mandrels and methods of using the same for installing and positioning expandable members, such as expandable bushings. 
     2. Description of the Related Art 
     Conventional installation tools are used to install bushings in openings within workpieces. These installation tools often have an expansion mandrel sized to fit within an opening of the bushing. Expansion mandrels are often formed of a hard metal, such as tool steel. After the bushing is slid over the expansion mandrel, the bushing and mandrel are simultaneously inserted into the opening of the workpiece. Unfortunately, an installer may have to manually hold the bushing at a desired position along the mandrel because the bushing may otherwise slide along the mandrel. This may cause complications during the installation process and increase the installation time. 
     After the bushing and corresponding mandrel are placed in the opening, the mandrel is pushed or pulled through the opening of the bushing to expand the bushing. The bushing is expanded until an interference fit is formed between the bushing and workpiece. During the expansion process, the installation tool must be adequately aligned with the opening in the workpiece in order to reduce side loads applied to the mandrel. For example, if a longitudinally-extending axis of the mandrel is misaligned with a longitudinally-extending axis of the opening, undesirable side loads may be applied to the mandrel. These side loads may cause excessive wear, high localized stresses (e.g., stresses in the workpiece, expandable member, mandrel, etc.), and improper positioning of the bushing. The excess wear can result in frequent part replacement. The high stresses can lead to part failure, such as breaking of the mandrel and/or damage to the workpiece, which can cause manufacturing delays. Thus, side loads can undesirably increase the costs for replacing and maintaining tools, frequency and length of manufacturing delays, and reduce the quality of the installed bushings. 
     Bushings are often installed in longitudinally-extending holes positioned along angled surfaces of workpieces. That is, the longitudinal axes of the holes are not orthogonal to the surfaces of the workpieces. An installation tool having an angled nose cap may be used to install bushings in these types of holes. The angled nose cap is a unitary structure fixedly coupled to a pull gun. A front face of the nose cap is angled so as to align the mandrel with the longitudinally-extending axis of the hole in the workpiece. 
     When the angled surface of the nose cap is placed against the surface of the workpiece adjacent the opening, the mandrel can pass through the nose cap and the bushing located in the workpiece. Unfortunately, the user has to select an appropriately angled nose cap for aligning the mandrel with the hole. A single angled nose cap is only suitable for use with a rather narrow range of angles. To select an appropriate angled nose cap, an installer measures the angle defined by the longitudinally-extending axis of the hole in the workpiece and the working surface of the workpiece. An angled nose cap is then selected corresponding to the measured angle. The angled nose caps are often indexed for various surface angles. 
     Many indexing tools require a minimum surface size for properly taking angle measurements. Unfortunately, the surface angle of the workpiece may be difficult to measure because the area of the surface surrounding the through-hole in the workpiece may be relatively small. Indexing tools may also be unable to measure adequately the curvature of the workpiece&#39;s curved surfaces. Additionally, it may be difficult to find any suitable “square” features or edges of the workpiece which are used for orienting the handpiece and associated mandrel. Thus, proper installation of expandable members may be difficult and require complicated measuring equipment. 
     Additionally, in order to install bushings at different locations, a user may be required to select and use different angled nose caps for use with a single installation tool. Because the installer has to remove and couple various angled nose caps, the installation time can be undesirably long. 
     In an alternative method, a spacer is used to align a mandrel of an installation tool with a hole in a workpiece. The spacer provides a surface that is perpendicular to a longitudinal axis of the hole. Similar to the angled nose caps, the angle of the workpiece&#39;s surface has to be determined before selecting an appropriately sized spacer. Additionally, multiple spacers are often needed for properly installing bushings at different locations. 
     Consequently, conventional installation tools may not adequately meet certain quality and installation needs. 
     BRIEF SUMMARY 
     In some embodiments, an apparatus for installing an expandable member in an opening of a work piece comprises an expansion mandrel sized to fit within a passageway of the expandable member such that the expandable member radically expands when the mandrel moves through the passageway and an installation tool having a distal portion and a drive system. The mandrel moves along a predetermined path when the drive system is activated. A self-aligning nose cap assembly has an opening surrounding the expansion mandrel. The apparatus further includes a joint retractably coupling the self-aligning nose cap assembly and the installation tool such that the self-aligning nose cap assembly moves relative to the distal portion of the installation tool and the mandrel. 
     In some embodiments, the self-aligning nose cap assembly has an outer surface for engaging the work piece and an opposing curved surface for sliding along a complementary curved outer surface of the distal portion. The nose cap assembly has a partially spherical surface that slid ably engages a complementary partially spherical surface of the distal portion. 
     In some embodiments, a nose cap assembly for use with a puller device, which actuates an elongated mandrel, comprises an outer housing dimensioned for retractably coupling to a distal portion of the puller device and an engagement portion physically connected to the outer housing. The engagement portion defines a first surface, a second surface opposite the first surface, and an aperture extending between the first surface and the second surface. The aperture is sized to receive the elongated mandrel. The second surface is curved to slid ably engage a curved outer surface of the puller device in response to the first surface being pressed against a work piece. 
     In some embodiments, an axial cross-section of the aperture is sufficiently large to permit the engagement portion to rest securely against a surface of the work piece. The surface of the work piece is angled to a substantially linear path of travel of the mandrel. In some embodiments, the surface of the work piece and the linear path of travel of the mandrel define an angle less than about, for example, 15 degrees. In some embodiments, the surface of the workpiece and the linear path of travel of the mandrel define an angle of at least 3 degrees. In other embodiments, the surface of the workpiece and the linear path of travel of the mandrel define an angle of at least 2 degrees. In yet other embodiments, the surface of the workpiece and the linear path of travel of the mandrel define an angle of at least 1 degree. In some embodiments, at least a portion of the curved second surface of the engagement portion has substantially the same curvature as at least a portion of the curved outer surface of the puller device. In one embodiment, the second surface of the engagement portion forms a generally partially spherical surface. 
     In some embodiments, a method of installing a member into a workpiece comprises positioning a mandrel through an opening in the workpiece. The opening defines a longitudinal axis that is not perpendicular to a surface of the workpiece surrounding the opening. A nose cap assembly is pushed against the surface of the workpiece causing rotation of the nose cap assembly relative to the mandrel while the mandrel extends through the opening in the workpiece. The nose cap assembly is rotated a sufficient distance to generally align the mandrel with the longitudinal axis of the opening in response to the pushing. 
     In some embodiments, the surface of the workpiece and an imaginary plane orthogonal to the longitudinal axis define an angle greater than about 1 degree. In other embodiments, the surface of the workpiece and an imaginary plane orthogonal to the longitudinal axis define an angle greater than about 2 degrees. In other embodiments, the surface of the workpiece and an imaginary plane orthogonal to the longitudinal axis define an angle greater than about 3 degrees. In some embodiments, the method further comprises expanding a member a sufficient amount to form an interference fit between the member and the opening of the workpiece after aligning the mandrel with the longitudinal axis of the opening. 
     In some embodiments, a mandrel for expanding a member in a workpiece is provided. The mandrel comprises a main body having a tapered portion, a mounting portion, and a coupling portion. The mounting portion is interposed between the tapered portion and the coupling portion. The tapered portion is configured to radially expand the member when the tapered portion is moved through a passageway extending through the member. A retention sleeve is received by the mounting portion of the main body. The retention sleeve is positioned axially along the main body such that the sleeve engages at least a portion of the member when the coupling portion of the main body is coupled to an installation tool. The retention sleeve is generally more compressible than the tapered portion of the main body. 
     In some embodiments, the retention sleeve is made of a first material having a first modulus of elasticity. The tapered portion is made of a second material having a second modulus of elasticity. The first modulus of elasticity is substantially less than the second modulus of elasticity. The retention sleeve can be comprised of steel (e.g., spring steel), plastics, polymers, wear resistant materials (e.g., nylon), and the like. In some embodiments, the main body comprises mostly metal and the retention sleeve comprises mostly plastic. In some embodiments, the main body is formed mostly of steel and the retention sleeve is formed mostly of rubber. 
     In yet another embodiment, a method of installing an expandable member comprises placing an expandable member on an expansion mandrel such that at least a portion of the expansion member is held by a retention sleeve of the mandrel. At least a portion of the expandable member is positioned in an opening of a workpiece while the expandable member is held by the retention sleeve. At least a portion of the mandrel is moved through a through-hole in the expandable member to disengage the expandable member and the retention sleeve. The expandable member is expanded by moving a tapered portion of the expansion mandrel through the through-hole of the expandable member. The expandable member is expanded an amount sufficient to form an interference fit with the workpiece. At least a portion of the retention sleeve is more compliant than at least a portion of the tapered portion of the mandrel. In some variations, at least a portion of the retention sleeve is substantially more compliant than one or more portions of the tapered portion. In some variations, at least a portion of the retention sleeve is more compliant than a portion of the expandable member defining the through-hole. 
     In yet other embodiments, a device for expanding an expandable member comprises means for expanding the expandable member from a first configuration to a second configuration when the means for expanding is moved through an opening in the expandable member, and means for retaining the expandable member in the first configuration on the means for expanding. The means for retaining is coupled to the means for expanding. In some variations, the means for retaining is more compressible than a portion of the means for expanding that expands the expandable member. In one variation, the means for retaining is substantially more compressible than a portion of the means for expanding that expands the expandable member. In some variations, the means for retaining tightly surrounds the means for expanding. 
     In yet other embodiments, a seating assembly for moving an installed member in a workpiece comprises a seat backing having a first surface and an opposing second surface, an elongated rod sized to fit within a passageway of the member. The elongated rod comprises a first end, a second end, and a body extending between the first end and the second end. The first end of the elongated rod is configured to be coupled to the seat backing. A seat base has an aperture dimensioned to receive the elongated rod, a first surface for engaging the workpiece, and a second surface. The second surface of the seat base and the second surface of the seat backing configured to form a joint which rotatably connects the seat backing and the seat base such that the elongated rod moves with respect to the seat base when the first surface of the seat base engages the workpiece and the rod extends through the aperture of the seat base and the passageway of the member. 
     In some embodiments, a method of moving a member installed in a workpiece comprises inserting a coupling end of an elongated rod through a through-hole of the member. The coupling end of the elongated rod is coupled to a puller tool such that the member and workpiece are at least partially sandwiched between a seat base surrounding the rod and the puller tool. The elongated rod is rotated about a joint formed by a seat backing and the seat base. The elongated rod is rotated an amount sufficient to align the elongated rod with a longitudinal axis of the through-hole. The elongated rod is pulled towards the puller tool with sufficient force to move the member relative to the workpiece. 
     In some embodiments, a system for positioning a member installed in a workpiece is provided. The system comprises a seat backing, a rod, and a seat base. The rod extends from the seat backing. The rod has a coupling end and a main body extending between the seat backing and the coupling end. The coupling end is coupleable to a puller device. The seat base has an opening configured to receive the main body of the rod. The seat base and seat backing cooperate to allow the rod to move laterally in a through-hole in a member installed in a workpiece when the seat base is pulled against the workpiece. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn, are not intended to convey any information regarding the actual shape of the particular elements, and have been solely selected for ease of recognition in the drawings. 
         FIG. 1A  is a side elevational view of an installation system having a self-aligning nose cap assembly attached to an installation tool and an expansion mandrel for expanding an expandable member, according to one illustrated embodiment. 
         FIG. 1B  is a side elevational view of the installation system of  FIG. 1A  where the self-aligning nose cap assembly engages a workpiece and is rotated to a raised position. 
         FIG. 1C  is a side elevational view of the installation system of  FIG. 1A  where the self-aligning nose cap assembly engages a workpiece and is rotated to a lowered position. 
         FIG. 2  is a side elevational view of the installation system of  FIG. 1A  where the self-aligning nose cap assembly has been removed. 
         FIG. 3A  is a side elevational view of a portion of the installation system of  FIG. 1A  engaging a workpiece during an installation process. 
         FIG. 3B  is a cross-sectional view of the portion of the installation system and workpiece of  FIG. 3A  where the mandrel extends through an expandable member positioned within the workpiece. 
         FIG. 3C  is an enlarged cross-sectional view of a portion of a distal tip of an installation system and a portion of an engagement portion of the nose cap assembly. 
         FIG. 4A  is a top elevational view of the distal tip of the installation system of  FIG. 1A . 
         FIG. 4B  is a cross-sectional view of the distal tip of  FIG. 4A  taken along a line  4 B- 4 B. 
         FIG. 5  is a side elevational view of a mandrel having a retention sleeve disposed around a main body, according to one illustrated embodiment. 
         FIG. 6  is a side elevational view of the main body of  FIG. 5 . 
         FIG. 7  is a side elevational view of the retention sleeve of  FIG. 5 . 
         FIG. 8  is a top elevational view of the retention sleeve of  FIG. 5 . 
         FIG. 9A  is a cross-sectional view of the retention sleeve of  FIG. 7  taken along a line  9 A- 9 A. 
         FIG. 9B  is a cross-sectional view of a retention sleeve, according to another illustrated embodiment. 
         FIG. 10  is a side elevational view of a retention sleeve, according to another illustrated embodiment. 
         FIG. 11  is a side elevational view of a retention sleeve, according to yet another illustrated embodiment. 
         FIG. 12  is a flowchart showing a method of installing an expandable member according to one embodiment. 
         FIG. 13  is a side elevational view of a seating apparatus having a seating assembly and an installation system where an expandable member and workpiece are sandwiched between the seating assembly and installation system, according to one illustrated embodiment. 
         FIG. 14  is a partial cross-sectional view of the seating assembly, workpiece, and expandable member of  FIG. 13 . 
         FIG. 15  is a front elevational view of a seat backing of the seating assembly of  FIG. 13 . 
         FIG. 16  is a cross-sectional view of the seat backing of  FIG. 15  taken along a line  16 - 16 . 
         FIG. 17  is a side elevational view of a seat base of the seating assembly of  FIG. 13 . 
         FIG. 18  is a front elevational view of the seat base of  FIG. 17 . 
         FIG. 19  is a cross-sectional view of the seat base of  FIG. 17  taken along a line  19 - 19  of  FIG. 17 . 
         FIG. 20  is a cross-sectional view of an expandable member positioned within an opening of a workpiece. 
         FIGS. 20A-20E  are cross-sectional views of expandable members positioned within openings of workpieces. 
         FIG. 21  is a side elevational view of a seating assembly spaced from the expandable member and workpiece of  FIG. 20 . 
         FIG. 22  is a side elevational view of the seating assembly of  FIG. 21  having a pull rod extending through the expandable member. 
         FIG. 23  is a cross-sectional view of the seating assembly, expandable member, and workpiece of  FIG. 22  taken along a line  23 - 23 . 
         FIG. 24  is a side elevational view of a seating assembly engaging an expandable member which is positioned in a workpiece. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the art will understand that the disclosed embodiments may be practiced without these details. 
     Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is as “including, but not limited to.” 
     The headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed embodiments. The following description relates to expandable members and installation systems, such as self-aligning installation systems and seating apparatuses for installing the expandable members. For purposes of this description and for clarity, a self-aligning installation system will be described and then a description of its components will follow. Another self-aligning system, namely a seating apparatus for repositioning an installed expandable member, is then described. The terms “proximal” and “distal” are used to describe the illustrated embodiments and are used consistently with the description of non-limiting exemplary applications. The terms proximal and distally are used in reference to the user&#39;s body when the user operates an installation system, unless the context clearly indicates otherwise. 
     Overview of Installation System 
       FIG. 1A  shows an installation system  100  including an installation tool  104 , a self-aligning nose cap assembly  110 , and an expansion mandrel  120  extending outwardly from the nose cap assembly  110 . Generally, the installation system  100  can be used to install an expandable member in a hole in a workpiece. The nose cap assembly  110  can move relative to the installation tool  104  and/or mandrel  120  in order to align the mandrel  120  with the expandable member. Proper alignment of the mandrel  120  may reduce, limit, or prevent off-axis loads (e.g., side loads) applied to the mandrel  120  before, during, and/or after an expansion process, as discussed in more detail below. Thus, the installation system  100  can install an expandable member in a hole. 
     The installation tool  104  includes a main body  124  that is coupled to a grip  128 . The user can manually grasp the grip  128  for comfortably holding and accurately positioning the installation system  100 . The illustrated grip  128  is a pistol grip. However, other types of grips can be utilized. 
     The installation tool  104  can be driven electrically, hydraulically, pneumatically, or by any other suitable drive means. In some embodiments, the main body  124  houses a drive system (as described in connection with  FIG. 4B ) that can drive the mandrel  120 , preferably along a predetermined path  127  (e.g., a line of action) in a proximal direction and/or distal direction. A pair of fluid lines  130 ,  132  provides pressurized fluid (e.g., pressurized gas, liquid, or combinations thereof) to a piston drive system that actuates the mandrel  120 . One of ordinary skill in the art can select the type of drive system used to achieve the desired motion of the mandrel  120 . 
     The cap assembly  110  allows expandable members to be installed in holes that may or may not be perpendicular to a surface of a workpiece. For example, the cap assembly  110  can move to accommodate an angled or curved surface of a workpiece in order to install an expandable member in a hole which is at an oblique angle relative to the surface of the workpiece. To accommodate angled surfaces, the cap assembly  110  can be substantially rotationally unrestrained. As shown in  FIG. 1B , the cap assembly  110  can be rotated upwardly (indicated by an arrow  125 ) to a raised position when engaging a workpiece  131  (shown in phantom). As shown in  FIG. 1C , the cap assembly  110  can be rotated downwardly (indicated by an arrow  126 ) to a lowered position. 
     One or more joints can be formed between the cap assembly  110  and installation tool  104 . As used herein, the term “joint” is a broad term that includes, but is not limited to, the region of contact between two elements that permits relative movement between the two elements. Joints can permit rotational and/or axial movement. In some embodiments, the joint is a structure that physically connects two elements while permitting relative movement between the elements. The term “rotational joint” is a broad term that includes, without limitation, a joint that has at least one rotational degree of freedom with substantially no axial movement in at least one direction. For example, a rotational joint can be in the form of a swivel joint or pivot joint. A pivot joint includes, without limitation, a joint that is generally rotationally unrestrained in at least two rotational degrees of freedom. In some embodiments, a pivot joint is rotationally unrestrained in three rotational degrees of freedom. Joints can have some amount of joint friction and joint elasticity depending on the desired play and movement. 
     The cap assembly  110  of  FIG. 1A  is slidably coupled to a distal tip or portion  140  (see  FIG. 2 ) of the installation tool  104 . The illustrated installation tool  104  is in the form of a handpiece tool. In some embodiments, the cap assembly  110  has three rotational degrees of freedom to provide movement like a ball and socket joint. As shown in  FIGS. 1B and 1C , the cap assembly  110  rotates with respect to the mandrel  120  and installation tool  104 . During installation of the expandable member, the cap assembly  110  can continuously align the mandrel  120  with the expansion member to ensure proper installation of the expansion member. 
     The mandrel  120  comprises an elongated body configured to radially expand the expandable member when the mandrel  120  is moved axially through a through-hole in the expandable member. As used herein, the term “mandrel” is a broad term and includes, but is not limited to, an elongated member having at least one tapered portion or expanded portion used to expand an expandable member. In some embodiments, a gradually tapered portion of a mandrel can be used to radially expand the expandable member so as to produce an interference fit between the expandable member and workpiece. Mandrels can have a one-piece or multi-piece construction. In some embodiments, the mandrels have a unitary body. In other embodiments, the mandrels have a multi-piece construction. For example, a mandrel can be a split mandrel and/or may have one or more sleeves, such as the retention sleeves discussed below. 
     As used herein, the term “expandable member” is a broad term and includes, but is not limited to, a bushing, washer, sleeve (including a split sleeve), fitting, fastener, nut plate, structural expandable member (e.g., expandable members that are incorporated into structural workpieces), and other structures that are suitable for coupling to a workpiece. The expandable member can be expanded from a first configuration to a second configuration. In some embodiments, for example, the expandable member is a bushing that can be radially expanded in order to form an interference fit with a through-hole in a workpiece. Expandable member refers to a member in a pre-expanded state and post-expanded state unless the context clearly dictates otherwise. Various types of expansion processes can be employed to expand the expandable members. In a cold expansion process, for example, the expandable member is radially expanded without appreciably raising the temperature of the expandable member to produce residual stresses in the workpiece and/or expandable member to enhance fatigue performance. The residual stresses are preferably compressive stresses that can minimize, limit, inhibit, or prevent crack initiation and/or crack propagation. 
     An expandable member can be installed in various types of workpieces. As used herein, the term “workpiece” is broadly construed to include, without limitation, a parent structure having at least one hole or opening suitable for receiving an expandable member. The opening can be a through-hole, blind hole, or other type of hole. In some embodiments, the expandable member can be installed in a structural workpiece, such as a bulkhead, fuselage, engine or other structural member of an aircraft. The expandable members can also be installed in other transportation vehicles (e.g., automobiles, trains, watercraft, and the like), rails such as railroad track rails, medical devices (e.g., implants), bridges (e.g., suspension bridges, beam bridges, truss bridges, etc.), and the like. The workpiece preferably has sufficient mechanical properties such that the installation system  100  can install the expandable member while the member is positioned within the hole of the workpiece. The user may or may not have backside access to the workpiece. 
     Nose Cap Assembly 
       FIGS. 3A and 3B  show the nose cap assembly  110  engaging an angled surface  170  of a workpiece  152 . Generally, the nose cap assembly  110  includes an outer housing  212 , which surrounds at least a portion of the distal tip  140  and a biasing member  320 . As shown in  FIG. 3B , the outer housing  212  includes an engagement portion  210 , a tapered portion  300 , and a sidewall  302 . The engagement portion  210  contacts the surface  170  of the workpiece  152  and preferably defines an aperture  230  sized to receive the mandrel  120 . The tapered portion  300  extends between the engagement portion  210  and sidewall  302 . The sidewall  302  is a generally cylindrical body that extends rearwardly from the tapered portion  300  to a mounting portion  310 . The biasing member  320  is interposed between a seating portion  322  of the distal tip  140  and a seating portion  330  of the mounting portion  310 . 
     With continued reference to  FIG. 3B , the engagement portion  210  is a thickened portion of the housing  212  and defines a first surface  220  for contacting the workpiece  152  and an opposing second surface  222  for slidably engaging the distal tip  140  of the installation tool  104 . The aperture  230  extends between the first surface  220  and second surface  222 . 
     The first surface  220  can be a generally flat surface extending continuously and uninterruptedly about the aperture  230 . As shown in  FIG. 3B , the first surface  220  can rest securely against the surface  170 . It is contemplated that the first surface  220  can have other configurations suitable for engaging the workpiece  152 . 
     The illustrated second surface  222  is a concave surface that mates with the convex surface  250  of the distal tip  140 . In some embodiments, at least a portion of the second surface  222  has substantially the same curvature as at least a portion of the outer surface  250 . The second surface  222  is preferably a partially spherical surface shaped to generally match the partially spherical surface  250  of the distal tip  140 . As shown in  FIG. 3C , for example, the radius R 1  of the arcuate surface  222  can be generally equal to or slightly greater than the radius R 2  of the arcuate surface  250 . The surfaces  222 ,  250  can have other configurations to achieve the desired movement of the nose cap assembly  110 . For example, the surfaces  222 ,  250  may or may not be true geometric spherical surfaces. In some embodiments, the surfaces  222 ,  250  may be partially ovoid. One of ordinary skill in the art can select the shape of the surfaces  222 ,  250  to achieve the desired movement between the nose cap assembly  110  and installation tool  104 . 
     When the engagement portion  210  contacts the workpiece  152 , the second surface  222  can slide along the outer surface  250  of the distal tip  140  until the mandrel  120  is properly aligned with the expandable member  144 . The frictional forces between the surfaces  222 ,  250  can be reduced or increased to reduce or increase, respectively, the force required to pivot the nose cap assembly  110 . In some embodiments, the second surface  222  and outer surface  250  are generally smooth surfaces for reduced frictional forces. For example, the surfaces  222 ,  250  can be polished surfaces (e.g., highly polished surfaces). In some embodiments, the surfaces  222 ,  250  are coated with a material, such as a lubricious material. Thus, various types of surface treatments or fabrication techniques can be used to achieve the desired frictional interaction. 
     The illustrated surface  222  and/or surface  250  can be formed of a polymer, such as synthetic resins like polytetrafluoroethylene (PTFE), TEFLON®, nylon, NEDOX® CR+, blends, mixtures, etc. The entire outer housing  212  can be made of a polymer, such as nylon. Alternatively, the polymer may form a layer that defines the surface  222 . 
     With reference again to  FIG. 3B , the tapered portion  300  of the outer housing  212  extends outwardly and rearwardly from the engagement portion  210  to the sidewall  302 . In the illustrated embodiment, the tapered portion  300  extends outwardly a sufficient distance to accommodate a positioning system  400  which is described in connection with  FIG. 4B . 
     The sidewall  302  surrounds and protects the distal tip  140  of the installation tool  104 . The proximal end of the sidewall  302  forms the mounting portion  310 . In the illustrated embodiment, the seating portion  330  extends inwardly from the mounting portion  310  and engages one end of the biasing member  320 . The other end of the biasing member  320  engages the seating portion  322 . As such, the biasing member  320  is constrained between the seating portions  320 ,  322 . 
     The illustrated biasing member  320  is a spring in a generally compressed state that applies a proximally directed force to the mounting portion  310 , thereby pushing the outer housing  212  in the proximal direction to maintain contact between the nose cap assembly  110  and distal tip  140 . The biasing member  320  can provide tactile feedback to the user to facilitate positioning of the installation tool  104 . The resistance provided by the biasing member  320  can help a user to controllably align the mandrel  120 . Additionally, the biasing member  320  can bias the nose cap assembly  110  to a neutral position (see  FIG. 1A ). When the nose cap assembly  110  is in the neutral position, a longitudinal axis  260  ( FIG. 3A ) of the nose cap assembly  110  is generally aligned with a longitudinal axis of the installation tool  104 . 
     To accommodate angled surfaces of workpieces, the nose cap assembly  110  can be configured to rotate an angle β. In some embodiments, the line of action  127  and longitudinal axis  260  of the nose cap assembly  110  defines the angle β. The line of action  127  preferably is a generally linear path. The angle β can be equal to or less than about 1 degree. In some embodiments, the nose cap assembly  110  can be configured to rotate an angle β which is equal to or less than about 2 degrees. In some embodiments, the nose cap assembly  110  can be configured to rotate an angle β which is equal to or less than about 3 degrees. In some embodiments, the nose cap assembly  110  can be configured to rotate an angle β which is equal to or less than about 4 degrees. In some embodiments, the nose cap assembly  110  can be configured to rotate an angle β, which is equal to or less than about 5 degrees, 7.5 degrees, 10 degrees, and 15 degrees. Additionally, other types of mounting arrangements can be used for pivotally mounting the nose cap assembly  110  to the installation tool  104 . The range of motion of the nose cap assembly  110  can be selected based on the size and type of expandable members, geometry of the workpiece, and skill level of the installer. 
     As noted above, the workpiece  152  defines the angled surface  170 , i.e., the surface  170  is not perpendicular to a hole or opening  191  in the workpiece  152 . The portion of the first surface  170  surrounding the opening  191  and an imaginary plane  171  ( FIG. 3A ) define an angle α. The imaginary plane  171  is approximately orthogonal to the longitudinal axis of a passageway or through-hole  164  of the expandable member  144  and/or the longitudinal axis of the opening  191  in the workpiece  152 . In the illustrated embodiment of  FIG. 3B , a longitudinal axis  180  of the passageway  164  of the expandable member  144  and a longitudinal axis  200  of the opening  191  in the workpiece  152  are generally collinear. As shown in  FIGS. 3A and 3B , the angle β is preferably equal to the angle α so that the nose cap assembly  110  rests stably against the workpiece  152 . 
     With continued reference to  FIG. 3B , the mandrel  120  extends through the aperture  230  of the housing  212 . The aperture  230  has an axial cross-section sufficiently large to permit the engagement portion  210  to rest securely against the surface  170  which is angled to a substantially linear path of travel  127  of the mandrel  120 . The size of the aperture  230  can be increased or decreased to increase or decrease, respectively, the rotational travel of the nose cap assembly  110 . The aperture  230  has a diameter that is generally about at least 3 times the diameter of the portion of the mandrel  120  positioned therein. In other embodiments, the aperture  230  has a width at least about 2.5 times, 2 times, 1.5 times, 1.25 times, or 1.1 times the width of the mandrel  120 . The illustrated aperture  230  is a generally circular opening; however, the aperture  230  can have other shapes. For example, the axial cross-section of the aperture  230  can be generally polygonal (including rounded polygonal), elliptical, or other suitable shape for surrounding the mandrel  120 . 
     Distal Tip of the Installation Tool 
       FIGS. 4A and 4B  show the distal tip  140  including a main body  350  defining an opening  410  for receiving the mandrel  120  and the distal surface  250 . As shown in  FIG. 4B , the main body  350  houses an actuating or drive system  352 . A main chamber  348  of the main body  350  can be dimensioned so as to closely receive the actuating system  352  and an alignment disk  360 . The main body  350  can also form a portion of the positioning system  400  described further below. 
     The actuating system  352  is spring-loaded and selectively actuates the mandrel  120  along the line of action  127  when activated. The illustrated actuating system  352  includes a retaining member  370  that grips a coupling end  363  of the mandrel  120 . The retaining member  370  bears against a follower  371 . An actuating system biasing member  364  engages the retaining member  370 . A piston assembly can drive the retaining member  370 . 
     The alignment disk  360  can facilitate proper alignment of the mandrel  120 . For example, the alignment disk  360  can be sized to receive and surround at least a portion of the mandrel  120  to inhibit, minimize, or substantially prevent lateral movement of the mandrel  120 . As the mandrel  120  is actuated, the alignment disk  360  can thus hold and guide the mandrel  120  along the desired predetermined path. In some embodiments, the mandrel  120  can displace the alignment disk  360  as the mandrel  120  moves axially through the housing  212 . Various types of collars, annular members, and the like can be used as an alignment disk  360 . Thus, the mandrel  120  can carry the disk  360  through the housing  212 . 
     In the illustrated embodiment of  FIG. 4B , the mandrel  120  extends through a passageway  380  of the alignment disk  360 . The passageway  380  is preferably sized for closely receiving at least a portion of the mandrel  120 . For example, the passageway  380  can have a width that is slightly greater than the width of the mandrel  120  disposed therein. In some embodiments, the width of the passageway  380  is less than about 0.0005 inches (0.013 mm) greater than the width of the portion of the mandrel  120  positioned therein. In other embodiments, the width of the passageway  380  is less than about 0.001 inches (0.025 mm), 0.003 inches (0.076 mm), 0.005 inches (0.127 mm), or 0.01 inches (0.25 mm) greater than the width of the portion of the mandrel  120  positioned therein. In some embodiments, the width of the passageway  380  is less than about 0.5%, 1%, 3%, 5%, or 7% greater than the width of the portion of the mandrel  120  positioned therein. The tolerancing of the passageway  380  and the outside surface of the mandrel  120  can be selected to achieve the desired mandrel alignment and frictional interaction. 
     The alignment disk  360  can be retained between the actuating system  352  and opening  411 . As illustrated in  FIG. 4B , the alignment disk  360  is positioned near the opening  411 , thereby ensuring proper positioning of the mandrel  120  with respect to an expandable member proximate the opening  411 . The alignment disk  360  can be axially retained by the positioning system  400 . If the nose cap assembly  110  is separated from the installation tool  104 , the system  400  ensures that the disk  360  remains properly positioned within a disk passageway  401 . Accordingly, the system  400  can act as a stop that limits the travel of the disk  360  in the proximal direction. 
     The positioning system  400  can comprise one or more positioning members  402  for controlling movement of the alignment disk  360  relative to the main body  350 . In the illustrated embodiment of  FIG. 4B , for example, a pair of diametrically opposed pins  402  are axially movable within corresponding through-holes  411  formed in the main body  350 . 
     The pins  402  can be spring-loaded so that they bias inwardly to engage the disk  360 . The ends of the pins  402  can protrude into the disk passageway  401  and contact the proximal end of the disk  360 . Alternatively, each pin  402  can have an externally threaded surface configured to threadably mate with internal threads of a corresponding through-hole  411 . Each pin  402  can be rotated about its longitudinal axis for axial movement along its corresponding through-hole  411 . Each pin  402  can be moved independently inwardly and/or outwardly to adjust the position of the alignment disk  360 . For example, the pins  402  can be rotated to laterally displace the alignment disk  360 . 
     To install different types or sizes of expandable members, for example, the illustrated mandrel  120  of  FIGS. 4A and 4B  may be replaced with another mandrel having a different geometry (e.g., a smaller or larger diameter). The illustrated alignment disk  360  may not be suitable for use with the new mandrel. Accordingly, the alignment disk  360  can likewise be replaced so that there is a tight tolerance between the passageway of the alignment disk and an outer surface  414  of the mandrel. The pins  402  can be positioned to accommodate alignment disks of different sizes. The new alignment disk can properly align the new mandrel. Thus, a variety of mandrels and alignment disks can be used with a single installation tool  104  thereby reducing the overall number of components required to install expandable members of different sizes. 
     Additionally or alternatively, the positioning system  400  of  FIG. 4B  can be used to adjust the pressure applied by the alignment disk  360  to the outer surface  414  of the mandrel  120 . For example, the alignment disk  360  can be a split disk that can be compressed inwardly or expanded outwardly to increase or decrease, respectively, the pressure applied to the outer surface  414  of the mandrel  120 . As such, the friction between the alignment disk  360  and mandrel  120  can be selectively adjusted as desired. Further, the split alignment disk  360  can advantageously be used with mandrels having different diameters. The size and type of alignment disks can be selected based on the desired installation procedure and mandrel configuration. 
     In alternative embodiments, the distal tip  140  is formed by an intermediate component configured to receive the nose cap assembly  110 . The intermediate component can be connector, adapter, or other structure of the installation tool  104  for removably or permanently coupling to the nose cap assembly. 
     Mandrel 
       FIG. 5  shows the mandrel  120  including a main mandrel body  500  and a retention sleeve  510 . The retention sleeve  510  can be used to engage at least a portion of an expandable member to inhibit or minimize movement of the expandable member before the expansion process. When the mandrel  120  extends through the expandable member  144 , as shown in  FIG. 3B , the retention sleeve  510  can extend at least partially through the passageway  164  of the expandable member  144 . 
       FIG. 6  shows the main body  500  including an expansion section  523 , the coupling portion  363 , and a mounting portion  517  therebetween for engaging the retention sleeve  510  (see  FIG. 5 ). The installation tool  104  can temporarily or permanently receive the coupling section  363 . The illustrated coupling section  363  has an enlarged proximal end  519  that can be received by the retaining member  370 , as shown in  FIG. 4B ; however, the coupling section  363  can have other configurations. 
     The mounting portion  517  is configured to receive at least a portion of the retention sleeve  510 . The illustrated mounting portion  517  of  FIG. 6  includes a circumferential recess  514  sized to receive a substantial portion of the retention sleeve  510 , as shown in  FIG. 4B . The depth and length of the recess  514  can be selected based on the thickness and length of the retention sleeve  510 . 
     The retention sleeve  510  is preferably securely retained in the recess  514  when the expandable member is slid on and off of the sleeve  510 . In some embodiments, the retention sleeve  510  tightly surrounds the mounting section  517 . Adhesives, bonding agents, fasteners, and the like can permanently couple the retention sleeve  510  to the main body  500 . In some embodiments, however, the retention sleeve  510  is removably coupled to the main body  500 . 
     As shown in  FIGS. 7 to 9A , the retention sleeve  510  can be a generally tubular body. An inner profile  538  of the retention sleeve  510  defines a first inner perimeter  542 , a second inner perimeter  544  greater than the first inner perimeter  542 , and a transition perimeter  546  extending therebetween. In the illustrated embodiment, the retention sleeve  510  has a somewhat frusta conical shape. However, the sleeve  510  can have a generally uniform cross-section.  FIG. 9B , for example, illustrates a tubular sleeve  510  having a substantially constant axial cross-section along its length. 
     The retention sleeve  510  of  FIG. 3B  can be configured to retain the expandable member  144  on the mandrel  120  during the entire installation process. The main body  500  causes most or all of the radial expansion of the expandable member  144 . Thus, the hands of the operator are free to perform other tasks. The expandable member  144  in a pre-expanded state can be coupled to the retention sleeve  510 . The expandable member  144  and mandrel  120  can then be inserted into the opening  191  of the workpiece  152 . In the illustrated embodiment of FIG.  4 B, the mandrel  120  is positioned such that the upper portion  560  of the retention sleeve  510  engages the alignment disk  360 . A lower section  562  of the sleeve  510  can engage at least a portion of the passageway  164  of the expandable member  144 . In some embodiments, the expandable member  144  can be captured between the mandrel  120  (e.g., the expansion section  523  of the mandrel  120 ) and the nose cap assembly  110 . The retention sleeve  510  can engage the housing  212 , alignment disk  360 , or other component of the nose cap assembly  110 . The sections  560 ,  562  can enhance the fit between the alignment disk  360  and expandable member  144 , respectively, to improve the overall alignment out of the mandrel  120  and expandable member  144 . 
     The illustrated retention sleeve  510  of  FIGS. 7 to 9A  includes a plurality of segmented portions  550 ,  552 ,  554 . The segmented portions  550 ,  552 ,  554  are separate annular bodies that can be moved relative to one another. For example, the segmented portions  550 ,  552 ,  554  can slide axially along the circumferential recess  514  of the mandrel  120 ; however, a retention sleeve may have a one-piece construction.  FIGS. 10 and 11  show retention sleeves  561  and  563 , respectively, that each has a continuous and uninterrupted tubular body. 
     The retention sleeve  510  can be made of polymers, plastics, rubbers, metals, combinations thereof, or other materials suitable for engaging and holding an expandable member. In some embodiments, the retention sleeve  510  comprises a compliant material. When compressed, the retention sleeve  510  can deform and bulge out around the expandable member  144 , as shown in  FIG. 3B . The compliant material can thus deform and promote a snug fit for expandable members of different sizes. In some embodiments, the sleeve  510  is made mostly of non-metal, e.g., a polymer material (e.g., nylon, polyurethane, etc.). The retention sleeve  510  can also be constructed from other types of synthetic or natural materials with suitable characteristics. One of ordinary skill in the art can determine the appropriate combination of material type, thickness, and sleeve shape to achieve the desired interaction between the retention sleeve  510  and the expandable member. 
     With reference again to  FIG. 5 , the retention sleeve  510  is spaced from a distal end  530  of the mandrel  120 . The expansion section  523  of the mandrel  120  extends distally from the retention sleeve  510  and preferably comprises a high wear material, such as metal (e.g., stainless steel, tool steel, titanium), ceramics, and the like. The high wear material can produce most or substantially all of the expansions of the member  144 , thereby limiting wear of the mandrel  120 . 
     In some embodiments, the main body  500  can be formed of first material and the retention sleeve  510  can be formed of a second material. The second material can have a modulus of elasticity that is less than the modulus of elasticity of the first material. In some embodiments, the second material can have a modulus of elasticity that is substantially less than the modulus of elasticity of the first material. In one embodiment, for example, the first material comprises mostly metal (e.g., steel, such as tool steel) and the second material comprises mostly plastic (including rubber). Accordingly, the retention sleeve  510  can be substantially more compliant than the main body  500 . 
     A retention sleeve can have a uniform or varying wall thickness. The retention sleeve  561  of  FIG. 10  has a wall thickness that gradually increases from a first end  565  to a second end  567 .  FIG. 11  shows the retention sleeve  563  having a generally uniform wall thickness along its length. 
     When the retention sleeve  510  is positioned in the expandable member  144 , the expandable member  144  can compress the sleeve  510 . The compressed sleeve  510  preferably exerts an outwardly directed reactive force against the passageway  164  to ensure that the expandable member  144  is securely retained on the mandrel  120  before, during, and after the expandable member  144  is placed in the opening  191  of the workpiece  152 . To expand the expandable member  144 , the mandrel  120  can be displaced to dislodge the retention sleeve  510  as discussed below. 
     Methods of Installing an Expandable Member 
       FIG. 12  is a flowchart showing a method of installing an expandable member according to one embodiment. At  700 , the expandable member  144  is positioned on the mandrel  120  by inserting the coupling end  363  of the mandrel  120  into the passageway  164  of the expandable member  144  in a pre-expanded state. The expandable member  144  is slid distally over the mandrel  120  until at least a portion of the expandable member  144  is fit snuggly around the retention sleeve  510 . 
     At  704 , the mandrel  120  and expandable member  144 , positioned on the distal side of the workpiece  152 , are inserted into the workpiece. At  706 , the coupling end  363  of the mandrel  120  protruding outwardly from the workpiece  152  is coupled to the installation tool  104  by inserting the coupling end  363  through the aperture  230  of the nose cap assembly  110 . The mandrel  120  is then advanced through the opening  410  of the distal tip  140  until the coupling end  363  is positioned to be coupled to the actuating system  352 . When the actuating system  352  is retracted, arms  513 ,  515  (see  FIG. 3B ) are moved proximally thereby pushing inwardly the engaging members  517 ,  519 , respectively, against the mandrel  120 . In this manner, the actuating system  352  selectively grips the mandrel  120 . 
     After the mandrel  120  is coupled to the installation tool  104 , the mandrel  120  and associated expandable member  144  can be aligned with the opening  191  in the workpiece  152 . At  706 , the mandrel  120  is inserted and advanced through the opening  191  to position at least a portion of the expandable member  144  therein. The opening  191  can closely receive the expandable member  144  to reduce the amount of expansion required to install the expandable member  144 , thereby reducing installation time. 
     At  707 , the nose cap assembly  110  can pivot when the front face  220  of the nose cap assembly  110  contacts the workpiece  152 . As shown in  FIGS. 3A and 3B , at least a portion of the expandable member  144  is within the opening  191  of the workpiece  152  while the expandable member  144  is held securely by the retention sleeve  510 . The mandrel  120  and installation tool  104  can be generally aligned with the longitudinal axis  200  of the opening  191  independent of the surface geometry of the workpiece  152 . 
     At  708 , the actuating system  352  retracts the mandrel  120  and the alignment disk  360  surrounding the mandrel  360 . During the retraction process, the nose cap assembly  110  can remain in generally continuous contact with the workpiece  152 . The mandrel  120  is drawn proximally through the expandable member  144  and cap assembly  110  so that the retention sleeve  510  moves proximally out of the expandable member  144 . 
     At  709 , the tapered distal expansion section  523  of the mandrel  120  is forcibly pulled through the passageway  164  causing radial expansion of the expandable member  144 . During this expansion process, the nose cap assembly  110  is pulled against the workpiece  152  and can rotate to minimize, limit, or prevent non-axial loading of the mandrel  120 . The mandrel  120  can thus be in uniaxial tension. If the mandrel  120  is misaligned, for example, the installation tool  104  and mandrel  120  may rotate with respect to the stationary nose cap assembly  110  until the mandrel  120  is brought into proper alignment. Accordingly, the mandrel  120  may be moved into alignment by the forces generated during the expansion process. If side loading occurs, the nose cap assembly  110  can move to minimize or eliminate the side loads. In this manner, stress levels in the installation tool  104 , workpiece  152 , and expandable member  144  may be minimized, thus reducing wear. The reduced stresses can reduce the frequency of part failure including, but not limited to, braking of the mandrel, damage to the workpiece, and the like. Moreover, the proper orientation of the mandrel  120  may ensure proper positioning of the installed expandable member  144 . 
     The material of the expandable member  144  can be radially displaced into the material of the workpiece  152  that defines the opening  191 . Cold working of the expandable member  144  may also cold work the material of the structural workpiece  152  to provide a fatigue benefit by creating compressive, residual stresses in the material surrounding and/or adjacent to the opening  191 . 
     The expandable member  144  is preferably expanded a sufficient amount to secure the expandable member  144  in the opening  191 . In some embodiments, an interference fit is formed between the expandable member  144  and workpiece  152 ; however, other types of fits are also possible. 
     At  710 , the mandrel  120  is removed from the installation tool  104 . Optionally, the installation tool  104  or mandrel  120 , or both, can be used to install another expandable member. To install different types or sizes of expandable members that require different mandrels, the alignment disk and/or nose cap assembly can be replaced. The installation tool  104  can thus install various types of expandable members in workpieces, which have complex surfaces, such as angled or non-angled surfaces, without requiring indexing or measuring of surface geometries. It is contemplated that the installation system  100  can be used to install expandable members in openings with or without backside access. 
     Overview of Seating Apparatus 
       FIG. 13  illustrates a seating apparatus  780  for adjusting the position of an installed expandable member  820 . The seating apparatus  780  includes an installation tool or puller tool  800  removably coupled to a self-aligning seating assembly  810 . One or more gaps can be formed between the expandable member  820  and a workpiece  822 . These gaps can often lead to undesirable movement between the expandable member  820  and workpiece  822 , thereby reducing fatigue performance of the assembled structure or inducing other problems in load transfer or corrosion. The seating apparatus  780  can reposition the installed expandable member  820  (e.g., an expandable member in a post-expanded position) to reduce the size or eliminate one or more of these gaps. Generally, the seating assembly  780  and puller tool  800  are drawn together to apply compressive forces to the expandable member  820  and workpiece  822  in order to reposition the expandable member  820  with respect to the workpiece  822 . 
     The seating apparatus  780  can reposition one or more expandable members that have been dislodged or otherwise moved over time. If the expandable member has moved an undesirable amount, the seating apparatus  780  can move the member to a desired location. An expandable member may be repositioned numerous times during its useful lifetime. 
     In some embodiments, including the illustrated embodiment of  FIG. 14 , the expandable member  820  is moved after it has been expanded so as to form a strong interference fit with the workpiece  822 . The seating apparatus  780  can also be used to reposition other types of members (including non-expandable members), fitting, and the like in workpieces. The seating assembly  810  and puller tool  800  are discussed separately below. 
     Seating Assembly 
       FIGS. 13 and 14  show the seating assembly  810  including a seat base  840 , a seat backing  842 , and a pull rod  841  extending from the seat backing  842  through the seat base  840 . A joint  861  is formed between the seat backing  842  and seat base  840 . The seat backing  842  slidably engages the seat base  840  such that the pull rod  841  can be pivoted or rotated with respect to the workpiece  822 . 
     With reference to  FIGS. 15 and 16 , the seat backing  842  is somewhat disk-shaped having an engagement surface  856 , a back surface  857  opposing the engagement surface  856 , and a passageway  865  extending between the surfaces  856 ,  857 . The passageway  865  is a longitudinally extending passageway sized to receive at least a portion of the rod  841 . 
     As shown in  FIGS. 17 to 19 , the seat base  840  is an annular member defining a surface  854  that engages the engagement surface  856  of the seat backing  842 . The surfaces  854 ,  856  can be generally similar to the surfaces  250 ,  222  described above in connection with  FIG. 3B . In some embodiments, for example, the surfaces  854 ,  856  are generally partially spherical surfaces that have similar radii. The surfaces  854 ,  856  can also have other configurations. 
     When the pull rod  841  is pulled proximally (as indicated by the arrow  812  of  FIG. 13 ), the rod  841  can move (e.g., rotate as indicated by the arrows  862 ,  864  and/or translate) to minimize, limit, or eliminate side loads on the pull rod  841 . If the expandable member  820  is installed into a workpiece having a non-uniform thickness, the position of the pull rod  841  can be independent of the geometry (e.g., the surface angle) of the workpiece. 
     With reference again to  FIG. 14 , the pull rod  841  includes a seating base end  850 , a puller tool end  853 , and a main body  855  extending therebetween. The puller tool end  853  is configured for engagement with the puller tool  800 . 
     The seating base end  850  is fixedly coupled to the seat backing  842  by threads, adhesives, fasteners (e.g., mechanical fasteners), or other suitable coupling means. Accordingly, the pull rod  841  and seat backing  842  form a multi-piece structure that can rotate together about the joint  861 . Alternatively, the pull rod  841  and seat backing  842  can have a one-piece construction. For example, the pull rod  841  and seat backing  842  can be monolithically formed through a molding and/or machining process. 
     As shown in  FIGS. 17-19 , the seat base  840  has a front face  870  for engaging the workpiece  822 , the surface  854 , and an aperture  872  for receiving the pull rod  841 . The size of the aperture  872  can be increased or decreased to increase or decrease, respectively, the travel of the pull rod  841 . The aperture  872  can be generally circular, non-circular, polygonal (including rounded polygonal), elliptical or any other shape for the desired range of movement of the pull rod  841 . 
     Puller Tool 
     The puller tool  800  of  FIGS. 13 and 14  can apply a proximally directed force to the rod  841 . Various types of puller tools can be used in combination with the seating assembly  810 . For example, the puller tool can be the installation tool  104  illustrated in  FIGS. 1A-1C . In alternative embodiments, the puller tool can be a pull apparatus as described in U.S. Pat. No. 4,187,708, which is hereby incorporated by reference in its entirety. Other known puller tools can be selected based on the forces required to reposition the expandable members. 
     Method of Using Seating Apparatus 
       FIGS. 13 ,  14 , and  20 - 23  illustrate a method of using the seating assembly  810  according to one embodiment.  FIG. 20  shows the expandable member  820  installed in the workpiece  822 . The expandable member  820  can be press fit, shrink fit, interference fit, or otherwise coupled to an opening or hole  902  extending through the workpiece  822 . The installation system  100  of  FIG. 1A  can be used to install the expandable member  820 . Of course, other types of tools can also be used to install the member  820 . 
     The illustrated workpiece  822  has a first surface  910  and opposing second surface  912  that are non-parallel. The second surface  912  is also not perpendicular with a longitudinal axis  958  (see  FIG. 20 ) of the opening  902 . A gap or space  830  is formed between the expandable member  820  and the workpiece  822 . The gap  830  is formed between an outwardly or radially extending flange  832  of the expandable member  820  and the first surface  910 , although any number of gaps can be present.  FIGS. 20A ,  20 B, and  20 C illustrate different types of gaps  830  (e.g., closing angle, open angle, or uniform gap, respectively) that can be formed between the flange  832  and workpiece  822 . Additionally, one or more gaps  830  can be formed between a generally tubular body  900  of the member  820  and the opening  902 , as shown in  FIGS. 20D and 20E . 
       FIG. 21  shows a first operation of using the seating assembly  810  to reposition the expandable member  820 . The seating assembly  810  is spaced from the expandable member  820  and the workpiece  822 . The pull rod  841  can be advanced proximally (indicated by the arrow  920 ) through a through-hole  930  of the expandable member  820 . The pull rod  841  is then advanced proximally such that the front face  870  of the seat base  840  contacts the surface  912  of the workpiece  822 . 
     As shown in  FIG. 22 , when the seat base  840  abuts against the workpiece  822 , the pull rod  841  can have a longitudinal axis  950  that is generally collinear with the longitudinal axis  956  (see  FIG. 20 ) of the through-hole  930  and/or the longitudinal axis  958  of the opening  902  in the workpiece  822 . In the illustrated embodiment of  FIG. 20 , the longitudinal axes  956 ,  958  are generally collinear. The longitudinal axes  956 ,  958  can also be at other orientations with respect to each other. 
     After positioning the seat assembly  810  through the expandable member  820 , the puller tool end  853  of the rod  841  can be inserted into a puller tool  800 . The workpiece  822  and member  820  are thus sandwiched between the seat base  840  and puller tool  800 , as shown in  FIGS. 22 and 23 . 
     As shown in  FIG. 13 , when the puller tool  800  applies a proximally directed force  812  to the rod  841 , a distal tip  960  of the tool  800  can engage the first surface  910  of the workpiece  822  such that the workpiece  822  remains generally stationary with respect to the tool  800 . In other embodiments, the distal tip  960  of the tool  800  can engage the flange  832  to properly seat the flange against the first surface  910  of the workpiece  822 . The puller tool  800  and seat assembly  810  are pulled together compressing the expandable member  820  and workpiece  822  therebetween. The compression forces can close any gaps between the member  820  and workpiece  822 . 
     During the compression process, side loads applied to the rod  841  may cause self-centering of the assembly  810 . If sufficient side loading occurs, the seat backing  842  can slide with respect to the seat base  840  to minimize or eliminate the side loads. During the compression process, the seating assembly  810  may self align to minimize, limit, or substantially eliminate side loads on the rod  841 . 
     The seating apparatus  780  can be used to reseat expandable members having a flange of other structure on a backside of a workpiece. For example, the seating apparatus  780  of  FIG. 13  can reposition the expandable member  820  wherein the flange  832  of the member  820  is adjacent the surface  912  of the workpiece  822 . 
       FIG. 24  shows another embodiment of a seating apparatus  998  including a seating assembly  1000  and an installation tool  1010 . The seating assembly  1000  is generally similar to the seating assembly  810 , except as detailed below. 
     The seating assembly  1000  has a seat backing  1020  disposed between a seat base  1030  and a cover  1040 . A biasing member  1050  extends between and engages the cover  1040  and seat base  1030 . A rod  1060  extends through an opening  1064  in the seat base  1030  and an opposing opening  1066  in the seat backing  1020 . A joint  1070  is formed between the seat backing  1020  and seat base  1030 . 
     The seat backing  1020  has a main body backing  1072  and an elongate member  1074  extending therefrom. The illustrated elongate member  1074  is a generally tubular member that defines a passageway  1076  sized to receive the end of the rod  1060 . When assembled, the elongate member  1074  extends through an opening  1078  in the cover  1040 . 
     The illustrated rod  1060  is threadably coupled to the seat backing  1020 . External threads  1080  on the rod  1060  can mate with internal threads  1082  on a passageway  1076 . In this manner, the rod  1060  can be rigidly coupled to the seat backing  1020 . Other coupling arrangements can be also be used. 
     The cover  1040  can be temporarily or permanently coupled to the seat base  1030 . The cover  1040  and seat base  1030  are sized to form a chamber  1041  suitable for accommodating the seat backing  1020  and rod  1020 , even when the seating backing  1020  and rod  1020  are moved. 
     The biasing member  1050  can press the seat backing  1020  against the seat base  1030 , thus ensuring that a surface  1043  of the seat backing  1020  bears properly against a surface  1045  of the seat base  1030 . Once the seating system  1000  is separated from the workpiece  1003 , the biasing member  1050  can move the seat backing  1020  and rod  1060  to a centered or neutral position. 
     All patents and publications mentioned herein are hereby incorporated by reference in their entireties. Except as described herein, the embodiments, features, systems, devices, materials, methods and techniques described herein may, in some embodiments, be similar to any one or more of the embodiments, features, systems, devices, materials, methods and techniques described in U.S. Pat. Nos. 3,566,662; 3,892,121; 4,187,708; 4,423,619; 4,425,780; 4,471,643; 4,524,600; 4,557,033; 4,809,420; 4,885,829; 4,934,170; 5,083,363; 5,096,349; 5,405,228; 5,245,743; 5,103,548; 5,127,254; 5,305,627; 5,341,559; 5,380,136; 5,433,100; U.S. patent application Ser. Nos. 09/603,857; 10/726,809; 10/619,226; 10/633,294; 11/824,559; and U.S. Provisional Patent Application No. 60/818,133, which are incorporated herein by reference in their entireties. In addition, the embodiments, features, systems, devices, materials, methods and techniques described herein may, in certain embodiments, be applied to or used in connection with any one or more of the embodiments, features, systems, devices, materials, methods and techniques disclosed in the incorporated U.S. patents and patent applications. 
     The articles disclosed herein may be formed through any suitable means. For example, the articles can be formed through injection molding, machining, and other methods disclosed herein. The various methods and techniques described above provide a number of ways to carry out the invention. Of course, it is to be understood that not necessarily all objectives or advantages described may be achieved in accordance with any particular embodiment described herein. 
     Furthermore, the skilled artisan will recognize the interchangeability of various features from different embodiments disclosed herein. Similarly, the various features and steps discussed above, as well as other known equivalents for each such feature or step, can be mixed and matched by one of ordinary skill in this art to perform methods in accordance with principles described herein. Additionally, the methods which are described and illustrated herein are not limited to the exact sequence of acts described, nor are they necessarily limited to the practice of all of the acts set forth. Other sequences of events or acts, or less than all of the events, or simultaneous occurrence of the events, may be utilized in practicing the disclosed embodiments. 
     Although the invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and obvious modifications and equivalents thereof. Accordingly, it is not intended that the invention be limited, except as by the appended claims.