Abstract:
A tool for installing a helical coil insert in a tapped hole formed in a workpiece includes a tubular body having a bore extending along its axis, a mandrel coaxially disposed in the bore of the tubular body, a motor for rotating the mandrel, and an air cylinder for applying an axial force to the mandrel. The tubular body includes a recess at one end for carrying a helical coil insert in alignment with the bore. An opening in the tubular body allows a user access to the recess. The tubular body is moveable to position the helical coil into selective engagement with the mandrel, whereby rotation of the mandrel installs the helical coil insert a selected depth in the tapped hole of the workpiece. In addition, the mandrel slides axially within the bore of the tubular body to remove the tang from the helical coil insert upon installation of the helical coil insert in the tapped hole.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates generally to tools for installing helical coil inserts into tapped holes and, more particularly, to such power installation tools having the ability to break off a tang of the helical coil insert.  
         BACKGROUND OF THE INVENTION  
         [0002]    Helical coil inserts are commonly installed into tapped holes of a workpiece so that threaded fasteners such as screws can be held more securely. These inserts are frequently used to improve the gripping of threaded fasteners made of relatively hard materials, such as various steel alloys, when installed in relatively soft parent materials, such as aluminum. Helical coil inserts typically include a diametrical tang used as a grip by a mandrel of the installation tool for screwing the helical coil insert into the tapped hole.  
           [0003]    Helical coil inserts of this kind are usually installed by pre-winding them to reduce their diameter, and then rotatably threading them into a tapped hole. Once installed, the inserts expand from their contracted diameters and press radially outwardly against the walls defining the tapped holes, whereby the insert is securely held in place. Power tools for installing inserts are typically driven by an air motor and include a tubular body having a threaded bore extending along its axis and an opening at one end of the body for placing an insert in the bore. A mandrel is rotated by the motor within the threaded bore into engagement with the insert. Advancement of the mandrel forces the insert through a pre-winder, which reduces the insert&#39;s diameter, and from there into a tapped hole in an adjacent workpiece.  
           [0004]    Once the insert is installed at the correct depth in the bore of the workpiece, the mandrel is reversed until it is removed from the insert. In many instances, particularly if a through-going hole is lined with an insert, the tang must be removed after installation as otherwise it would interfere with a bolt engaging the insert. To facilitate removal of the tang, a notch is conventionally provided in the wire near the point where the diametrical tang joins the adjacent coil convolution. Thus, after using a conventional power tool to install the insert, the installer uses a second tool to break the tang at the notch.  
           [0005]    This two-tool process is time consuming and inefficient, particularly when many bores must be lined with helical coil inserts, such as in a manufacturing setting. Great efficiencies and cost savings would be realized by combining and simplifying the helical coil insert installation and tang removal process.  
         SUMMARY OF THE INVENTION  
         [0006]    A single tool for installing a helical coil insert in a tapped hole formed in a workpiece and removing a tang from a leading coil convolution simplifies the helical coil insert installation process. The power installation tool according to the invention includes a tubular body having a bore extending along its axis. A recess preferably provided at one end of the tubular body carries a helical coil insert in alignment with the bore. An opening in the tubular body allows access to the recess for placing the insert in the recess. A mandrel is coaxially disposed in the bore of the tubular body to engage and rotate the helical coil insert for installation. More specifically, a hook on the leading end of the mandrel engages a tang on the helical coil insert for winding the helical coil insert prior to installation of the coil in the tapped hole of the workpiece. Further, the mandrel serves as a punch, movable to sever the tang from the helical coil insert upon full installation of the insert in the tapped hole of the workpiece. A motor rotates the mandrel to insert the helical coil insert a predetermined distance in the tapped hole. An air cylinder applies an axial force to the mandral to move it from a retracted position to an extended position where it removes the tang.  
           [0007]    In one embodiment, the air motor is offset axially from the tubular body and is connected to the mandrel by a gear train, whereby rotation of the motor shaft rotates the mandrel. It is preferred to include a drive sleeve in the tubular body for connecting the gear train to the mandrel.  
           [0008]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0010]    [0010]FIG. 1 is a perspective view of the power installation tool according to the invention;  
         [0011]    [0011]FIG. 2 is a partial sectional view of the power installation tool of FIG. 1;  
         [0012]    [0012]FIG. 3 is a partial sectional view of a helical coil insert carried by a recess in a bore of the power installation tool of FIGS. 1 and 2 prior to installation of the insert;  
         [0013]    [0013]FIG. 4 is a partial sectional view of the mandrel of the power installation tool of FIGS. 1 and 2 pre-winding a helical coil insert prior to installation of the insert in a bore of a workpiece;  
         [0014]    [0014]FIG. 5 is a partial sectional view of a gear train for driving a mandrel by a motor of the power installation tool of FIGS. 1 and 2;  
         [0015]    [0015]FIG. 6 is an exploded view of the mandrel, drive sleeve, and punch of the power installation tool of FIGS. 1 and 2;  
         [0016]    [0016]FIG. 6A is a more detailed view of the punch of FIG. 6;  
         [0017]    [0017]FIG. 7 is a partial sectional view of the mandrel of FIG. 6 driving the helical coil insert into the bore of the workpiece;  
         [0018]    [0018]FIG. 8 is a partial sectional view of the power installation tool with the mandrel extended to remove a tang of the helical coil insert;  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0020]    With reference to the drawings, a power installation tool  10  for installing helical coil inserts  12  having a tang  14  is shown. As shown best in FIG. 1, the power installation tool  10  according to the invention generally includes a gear housing  16  mounting an air cylinder  18 , an air motor  20 , and an adapter body  22 . With reference to FIGS. 2, 3, and  4 , a mandrel  24  for driving the helical coil insert  12  into a bore  26  of a workpiece  28  is received in a bore  30  extending axially through the entire length of the adapter body  22 .  
         [0021]    The mandrel  24  is rotated within the adapter body  22  by the air motor  20  through an air motor shaft  32  and a gear train as best shown in FIG. 5. Because the air motor  20  is offset relative to the axial bore  30  of the adapter body  22 , the gear train interconnects the shaft  32  and the mandrel  24 . The gear train includes a drive gear  34  rotated directly by the shaft  32  of the motor  20  and supported by a bushing  36 . More specifically, the shaft  32  rotates the spline  38  and the spline adaptor  40 , which coaxially mount the drive gear  34 . The spline adapter  40  includes an axially extending portion journalled in bushing  36  and a slot  42  aligned with a slot  44  on an inner diameter surface of gear  34 . A key  46  disposed in the aligned slots  42 ,  44  fix the drive gear  34  for rotation with the spline adapter  40 , and thus with the motor shaft  32 . The drive gear  34  includes teeth  48  to drive teeth  50  of an intermediate gear  52 , which is supported via a fixed axle  54 . A bushing  56  surrounds the fixed axle  54 , which is preferably press fit in the gear housing  16  and then secured by cover  58 , and permits the gear  52  to freely rotate about the axle  54  while its gear teeth  50  mesh with teeth  48  of the drive gear  34  and teeth  60  of the drive sleeve gear  62 , thereby transferring rotation from the drive gear  34  to the drive sleeve gear  62 . More specifically, gear  62  drives a drive sleeve  64 , which extends the length of the drive housing  66  of the adaptor  22 . An inner diameter surface of gear  62  is fixed to rotate with the drive sleeve  64  through a key  68  registering aligned slots  70 ,  72  of the drive sleeve  64  and gear  62 , respectively. Finally, gear washers  74  disposed coaxially on opposite sides of each gear  34 ,  52 ,  62  center the gear train in the gear housing  16  and ensure proper meshing of the gears  34 ,  52 ,  62 .  
         [0022]    With reference to FIGS.  2 - 4 , the drive sleeve  64  is coaxially mounted for rotation within the drive housing  66  and extends nearly the length thereof. At each end of the drive sleeve  64 , at an outer portion thereof, a needle bearing  76  spaces the drive sleeve  64  from the drive housing  66  and allows relative rotation thereof. Thus, when gear  62  rotates due to actuation of the air motor shaft  32 , the drive sleeve  64  similarly rotates within the drive housing  66 . The drive sleeve  64  also includes a longitudinal slot  78  formed along an interior surface for reception of a spline  80  of the mandrel  24 , as shown best in FIGS. 2 and 5. In this way, rotation of the drive sleeve  64  causes rotation of the mandrel  24 . Further, slot  78  permits the mandrel  24  to slide axially within the drive sleeve  64  while rotating as the mandrel  24  moves relative to the adapter body  22  for installation of the helical coil insert  12  and for removal of the tang  14  as will be discussed in more detail herein below.  
         [0023]    As illustrated in FIGS. 2 and 6, the mandrel  24  extends generally the length of the adaptor body  22  through bore  30  and includes first, second, and third cylindrical sections  82 , 84 , 86 . The first cylindrical section  82  includes a tip  88  for engaging the tang  14  of helical coil insert  12 . The tip  88  includes a central recess  90  for engagement of the tang  14  having a width generally equivalent to the wire thickness of the particular helical coil insert  12  as best shown in FIG. 6. The central recess  90  engages the tang  14  for installation of the helical coil insert  12  and generally serves to prevent the tang  14  from rotating relative to the mandrel  24 . Specifically, as the mandrel  24  is caused to rotate, the tang  14  is held in frictional engagement with the recess  90  and causes the helical coil insert  12  to rotate therewith.  
         [0024]    The tip  88  includes a first and second ramped portion  92 ,  93  for use in breaking the tang  14  from the helical coil insert  12  after insertion of the helical coil insert  12  into a workpiece  28 . The first ramped portion  92  includes a first surface  95  disposed in a general angular relationship to the longitudinal axis of the mandrel  24  while concurrently sloping down from a central axis of the mandrel  24  towards an outer diameter of the third cylindrical section  86 . In this manner, the first surface  95  slopes from a high point W across the body of the mandrel  24  and along the recess  90  to a low point X. In addition, the first surface  95  slopes from a point Y disposed generally along the edge of the recess  90  to a point Z disposed on the outer diameter of the third cylindrical section  86 , as best shown in FIG. 6.  
         [0025]    The second ramped portion  93  includes a second surface  97  disposed at an angular relationship to the longitudinal axis of the mandrel  24  while concurrently sloping down from the central axis of the mandrel  24  generally towards the outer diameter of the third cylindrical section  86 . In this manner, the first surface  95  slopes from a high point W′ across the body of the mandrel  24  and along the recess  90  to a low point X′. In addition, the first surface  95  slopes from a point Y′ disposed generally along the edge of the recess  90  to a point Z′ disposed on the outer diameter of the third cylindrical section  86 , as best shown in FIG. 6.  
         [0026]    The angular relationship of the second surface  97  to the longitudinal axis of the mandrel  24  is generally opposite to the angular relationship of the first surface  95  to the longitudinal axis of the mandrel  24 . Specifically, the high point W of the first surface  95  is disposed across the recess  90  from the low point X′ of the second surface  97  while the high point W′ of the second surface  97  is disposed across the recess  90  from the low point X of the first surface  95 , as best shown in FIG. 6A.  
         [0027]    The second cylindrical section  84  is disposed adjacent the first cylindrical section  82  and includes a larger diameter than that of the first cylindrical section  82  such that the intersection of the first and second cylindrical sections  82 , 84  creates a first annular shoulder  94  as best shown in FIG. 3. The third cylindrical section  86  is disposed adjacent the second cylindrical section  84  and includes a larger diameter than that of the second cylindrical section  84 . As such, the junction of the second and third cylindrical sections  84 , 86  creates a second annular shoulder  96 . The third cylindrical section  86  further includes the spline  80  disposed generally opposite the second annular shoulder  96 . Spline  80  provides for the mandrel  24  to rotate with the drive sleeve  64  relative to the housing  66  as will be discussed further below.  
         [0028]    The adaptor body  22  includes the housing  66  coaxially aligned with a pre-winder sleeve  98  and a pre-winder  100 . Bore  30  extends coaxially through all three portions. Housing  66  is a generally cylindrical member having bore  30  formed therethrough and includes a first series of threads  102  for attachment to the gear housing  16  and a second series of threads  104  to assist in fixedly attaching the housing  66  to the pre-winder sleeve  98 . The housing  66  further includes a pair of recesses  108  on an inner surface of bore  30  for receiving the needle bearings  76  as best shown in FIG. 5. The needle bearings  76  assist in rotation of the drive sleeve  64  and ultimately the mandrel  24  relative to the housing  66 .  
         [0029]    The pre-winder sleeve  98  is a generally cylindrical member having bore  30  extending axially therethrough and includes a first end abutting the housing  66 , a second end for slidably receiving the pre-winder  100 , and a slot  110  disposed generally between the first and second ends. The first end of the pre-winder sleeve  98  includes an axial flange  112  and an extension  114 , whereby the extension  114  is disposed generally at the base of the axial flange  112  and extends therefrom. In this manner, the intersection of the axial flange  112  and the extension  114  creates a recess  116  for receiving the housing  66 . A pre-winder retainer  118  is provided and axially surrounds the housing  66  and the pre-winder sleeve  98  at their intersection to fixedly maintain the housing  66  in contact with the recess  116 .  
         [0030]    The pre-winder retainer  118  includes a series of threads  120  and an extension  122  generally defining a recess  124  as best shown in FIG. 2. The threads  120  matingly receive the threads  104  of the housing  66  while the recess  124  receives the axial extension  114  of the pre-winder sleeve  98 . In this manner, as the threads  120  engage the threads  104  of the housing  66  and the recess  124  receives the extension  114  of the pre-winder sleeve  98 , the housing  66  and pre-winder sleeve  98  are held in a fixed relationship.  
         [0031]    The pre-winder sleeve  98  further includes a series of threads  126  for threadably receiving a stop  128 . The stop  128  is a cylindrical collar having a series of threads  132  disposed on an inner surface for mating engagement with the threads  126  of the pre-winder sleeve  98 . The stop  128  is axially adjustable relative to the pre-winder sleeve  98  by turning the stop  128  and allowing the threads  132  of the stop  128  to move relative to and on the threads  126  of the pre-winder sleeve  98 . Specifically, as the stop  128  is caused to rotate relative to the pre-winder sleeve  98 , the engagement of the threads  126 , 132  causes the stop  128  to axially move towards or away from the gear housing  16  depending on the direction of rotation. Once the desired position of the stop  128  is achieved, a stop washer  130  is provided to hold the stop  128  in the desired position relative to the pre-winder sleeve  98 . Adjustment of the stop  128  relative to the pre-winder sleeve  98  sets the depth that the pre-winder  100  is permitted to axially travel within the pre-winder sleeve  98  as will be discussed herein below.  
         [0032]    The pre-winder  100  is an elongate cylindrical member having bore  30  formed therethrough and includes a first end, a second end, and a foot portion  134 . The first end of the pre-winder sleeve  100  is slidably received by the second end of the pre-winder sleeve  98  such that the pre-winder  100  is allowed to slide within the pre-winder sleeve  98 . In addition, the first end of the pre-winder  100  includes a set screw  136  and an accompanying washer  138 . The set screw  136  and washer  138  extend from an outer diameter of the pre-winder  100  through the slot  110  of the pre-winder sleeve  98 . The set screw  136  and washer  138  are held in a fixed relationship to the pre-winder  100  and are permitted to slide relative to the pre-winder sleeve  98  in slot  110 . In this manner, the pre-winder  100  is allowed to axially slide relative to the pre-winder sleeve  98  but relative rotation therebetween is restricted by the set screw  136  and washer  138  in slot  110 .  
         [0033]    As best shown in FIGS. 4 and 7, the range of travel of the pre-winder  100  relative to the pre-winder sleeve  98  is governed by the placement of the stop  128 . The range of axial movement of the pre-winder  100  is governed by the distance between the end of the slot  110  and the location of the stop  128  as best seen in FIG. 7. Specifically, the distance the set screw  136  is permitted to move within slot  110  between the end of slot  110  and stop  128  defines the amount the pre-winder  100  is permitted to axially slide within the pre-winder sleeve  98 . As the stop  128  is moved toward the gear housing  16  the range of motion of the pre-winder  100  relative to the pre-winder sleeve  98  is increased. Conversely, as the stop  128  is rotated about the threads  126  of the pre-winder sleeve  98  away from the gear housing  16  the range of axial motion of the pre-winder  100  relative to the pre-winder sleeve  98  is reduced.  
         [0034]    In one embodiment, the foot portion  134  reacts against a surface of the workpiece  28  causing the pre-winder  100  to slide within the pre-winder sleeve  98  towards the gear housing  16 . As the pre-winder  100  travels closer to the gear housing  16 , the mandrel  24  extends outwardly from the foot portion  134  and deeper into the bore  26  of the workpiece  28 . The overall travel of the mandrel  24  through the foot portion  134  and into the workpiece  28  is governed by the amount the pre-winder  100  is permitted to slide relative to the pre-winder sleeve  98 . The distance the mandrel  24  travels determines the depth that the helical coil insert  12  may be inserted into the workpiece  28 . Adjustment of the stop  128  relative to the pre-winder sleeve  98  thus sets the depth that the mandrel  24  is permitted to travel into the bore  26  of the workpiece  28  and ultimately governs the placement of the helical coil insert  12 .  
         [0035]    The foot portion  134  includes bore  30  extending therethrough and a recess  140  for inserting a helical coil insert  12  therein. The foot portion  134  is disposed at a predetermined distance from the second end of the pre-winder  100 , whereby the offset distance or recess  140  between the foot portion  134  and the second end of the pre-winder  100  is governed by the overall length of the helical coil insert  12  as best shown in FIG. 3. The second end of the pre-winder  100  further includes a tapered edge  142  for facilitating insertion of the helical coil insert  12  in the recess  140 . With continued reference to FIG. 3, the foot portion  134  includes a reduced diameter bore  144  having threads  146  for engagement with the helical coil insert  12 . In this manner, the diameter of the helical coil insert  12  is reduced as the helical coil insert  12  is caused to rotate through the reduced diameter bore  144 . While the present invention discloses a reduced diameter bore  144  having threads  146  it should be understood that the reduced diameter bore  144  may be provided with other suitable means for constricting and securely holding the helical coil insert  12  and should be considered within the scope of the present invention.  
         [0036]    As previously mentioned, the pre-winder  100  is received by the pre-winder sleeve  98  and permitted to slide relative thereto with the travel of the pre-winder  100  governed by the position of the set screw  136  in slot  110 . In addition to the set screw  136 , the movement of the pre-winder  100  is further influenced by a spring  148 . Spring  148  is disposed between the first end of the pre-winder  100  and a spacer  150  as best shown in FIGS. 3 and 4. In this manner, the pre-winder  100  is biased in a first axial direction generally away from the gear housing  16 . Specifically, as the pre-winder  100  is caused to axially move in a second axial direction generally towards to the gear housing  16 , the spring  148  is compressed between the first end of the pre-winder  100  and the spacer  150 , thereby biasing the pre-winder  100  in the first axial direction. The pre-winder  100  is caused to axially travel along bore  30  in the second direction due to an external force applied to the foot portion  134  of the pre-winder  100 . In one embodiment, the force applied to the foot portion  134  is due to the foot portion  134  contacting a surface of the workpiece  28  as will be discussed in more detail below.  
         [0037]    The spacer  150  is disposed generally at the intersection of the housing  66  and the pre-winder sleeve  98  and includes a central cylindrical section  150  and an axial flange  154  having bore  30  extending through both central cylindrical section  152  and axial flange,  154 . The central cylindrical section  152  provides a surface  156  against which the spring  148  reacts while the axial flange  154  receives extension  114  of the pre-winder sleeve  98  to prevent axial movement of the spacer  150  within bore  30  as best shown in FIG. 3. In one embodiment, the spacer  150  is removable to adjust the spacing between the spring  148  and the first end of the pre-winder  100 .  
         [0038]    As previously discussed, the mandrel  24  serves to rotate the helical coil insert  12  into a workpiece  28 . In addition, the mandrel  24  further acts to break off the tang  14  on the helical coil insert  12  after sufficient insertion of the helical coil insert  12  into the bore  26  of the workpiece  28 . In this manner, a punch  160  is provided and reacts against the third cylindrical section  86  of the mandrel  24  to cause the mandrel  24  to move in the first axial direction away from the gear housing  16 . The punch  160  is disposed between the third cylindrical section  86  of the mandrel  24  and a port  162  of the air cylinder  18 . The punch  160  is an elongate body extending through bore  30  of the adapter body  22  having a connector  163  at one end and a punch foot  165  at an opposite end. The connector  163  is preferably a threaded male connector for reception in a threaded female connector at one end of a shaft  167  extending into an air cylinder  18 . The opposite end of the shaft  167  is coupled to a piston  169 , which reciprocates under the force of air pressure within the air cylinder  18 . The piston  169 , and thus the punch  160 , is biased to a retracted position by a compression spring  164  positioned coaxially about the shaft  167  between an end of the air cylinder  18  and the piston  169 . The punch  160  is free to move outwardly from the third cylindrical section  86  of the mandrel  24  against the bias of the spring  164 , which returns the punch  160  to its retracted position in the absence of the force of air pressure causing the piston  169  to compress the spring  164  within the air cylinder  18 .  
         [0039]    In one embodiment, the air cylinder  18  is remotely activated by an operator once the helical coil insert  12  has been fully installed into the workpiece  28 . Specifically, once the helical coil insert  12  is fully installed in the workpiece  28 , an operator activates the air cylinder  18  causing a rush of air to react against the piston  169  causing the piston  169  to reciprocate and move against the bias of spring  164 . Sufficient movement of the piston  169  in the first direction causes the shaft  167  to move in the first direction away from the gear housing  16  and cause the punch  160  to contact the third section  86  of the mandrel  24 . Due to the force exerted by the punch  160 , the mandrel  24  rapidly accelerates in the first axial direction causing the tip  88  to sever the tang  14  from the helical coil insert  12 .  
         [0040]    In another embodiment, the air cylinder  18  is automatically activated once the pre-winder  100  has fully traveled to a point where the set screw  136  has contacted the stop  128  and begins to move in the first direction under the bias of spring  148 . In this manner, as the pre-winder  100  begins to move in the first axial direction away from the gear housing  16 , the air cylinder  18  is activated by a sensor (not shown) disposed on the stop  128 . Specifically, once the set screw  136  of the pre-winder  100  contacts the stop  128 , the sensor is activated and sends a signal to actuate the air cylinder  18  once the set screw  136  disengages the stop  128 . While a sensor is disclosed it should be understood that any method of communication between the pre-winder  100  and the air cylinder  18  such as an electro-mechanical relationship is anticipated and should be considered within the scope of the present invention.  
         [0041]    In either embodiment, the mandrel  24  includes a spring  158  disposed adjacent to the axial flange  154  of the spacer  150  and the second annular shoulder  96  of the mandrel  24  to bias the mandrel  24  in the second axial direction or towards the gear housing  16  to return the mandrel  24  to a retracted position once the tang  14  is severed from the coil  12 . Specifically, when the punch  160  contacts the mandrel  24  and causes the mandrel  24  to move in the first direction the spring  158  is compressed and thus acts to bias the mandrel  24  in the second axial direction once pressure in the air cylinder  18  is released and the tang  14  is properly severed from the coil  12 . Return of the mandrel  24  to the retracted position enables another helical coil insert  12  to be inserted into the recess  140  of the adaptor body  22  and subsequently into a another bore  26  of workpiece  28 .  
         [0042]    With particular reference to FIGS. 2, 7, and  8  the operation of the power installation tool  10  will be described in detail. In use, helical coil insert  12  is placed in recess  140 , and aligned with bore  30  in adapter body  22 . To accommodate loading of the helical coil insert  12 , the pre-winder  100  is fully extended in the first direction due to the bias of spring  148  as shown in FIG. 3 such that the mandrel  24  does not extend into recess  140 . To begin the installation of the helical coil insert  12 , the installer places the power installation tool  10  against the workpiece  28  such that the bore  30  is coaxially aligned with the bore  26  of the workpiece  28 .  
         [0043]    Once the power installation tool  10  is properly aligned with the bore  26  of the workpiece  28 , the installer applies a force to the power installation tool  10  and concurrently actuates an air motor  20  to cause rotation of drive sleeve  64  through interconnection of gears  34 ,  52 ,  62  and shaft  32  of air motor  20 , as explained above. Drive sleeve  64  rotates mandrel  24  through connection of mandrel spline  80  in drive sleeve slot  78 . The tip  88  of mandrel  24  rotates in bore  30  while the pre-winder  100  abuts the workpiece  28 . When sufficient force is applied to the power installation tool  10 , the workpiece  28  will exert a reaction force on the pre-winder  100  causing the pre-winder  100  to slide within the pre-winder sleeve  98  in the opposite (second) direction. Once the pre-winder  100  has traveled sufficiently in the opposite direction against the bias of spring  148 , the tip  88  engages the helical coil insert  12  in recess  140 . Specifically, the tip  88  slides through helical coil insert  26  until the central recess  90  grabs tang  14  to rotate helical coil insert  12 . Mandrel  24  then rotates insert  12  into reduced diameter bore  144  to pre-wind insert  12  by contracting insert  12  through engagement of threads  146  of the reduced diameter bore  144 , as best shown in FIG. 4.  
         [0044]    Continued advancement of pre-winder sleeve  98  in the second direction further compresses spring  148  and causes pre-wound insert  12  to pass from reduced diameter bore  144  and into bore  26  of workpiece  28 . The pre-winder  100  will continue to advance until the set screw  136  contacts the stop  128  on the per-winder sleeve  98  as previously discussed and as shown in FIG. 7.  
         [0045]    Once the helical coil insert  12  reaches the desired depth within the bore  26  of the workpiece  28 , the air cylinder  18  is activated by either an external operation or an automatic control as previously discussed. In either case, once the air cylinder  18  is activated, a rush of air from the air cylinder  18  causes the piston  169  to move in the first direction against the bias of spring  164 . Sufficient movement of the piston  169  in the first direction causes the shaft  167 , and subsequently the punch  160 , to contact the mandrel  24 . Movement of the punch  160  concurrently causes the mandrel  24  to slide in the first direction against the bias of spring  164  and axially slide within bore  30  due to the interaction of the punch foot  165  and the third cylindrical section  86  of the mandrel  24 .  
         [0046]    Sufficient movement of the mandrel  24  in the first direction causes the ramped portion  92  of the tip  88  to sever the tang  14  from the helical coil insert  12 . Once the tang  14  is properly severed from the helical coil insert  12 , the mandrel  24  is caused to move in the second direction due to the bias imparted by spring  158  and back to its retracted position while the punch similarly moves in the second direction due to the bias of spring  164  on the piston  169 . At this point, the force exerted on the power installation tool  10  can be released, thereby allowing the pre-winder  100  to move in the first axial direction and back to a position whereat another helical coil insert  12  may be placed in recess  140 .  
         [0047]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.