Abstract:
A device and method of removing a rivet which has been installed on a work piece. The method includes clamping a hand held device having springs onto the work piece, engaging a drill with a drill bit of the hand held device, the springs applying a pre-load force to the drill bit, operating the drill, thereby causing the springs to apply an increased load force to the drill bit and causing the drill bit to drill into a button of the rivet, unclamping and removing the hand held device from the work piece, and using a compression tool to remove the rivet from the work piece. The compression tool includes a push out portion configured to push out the rivet, and a recess is disposed generally opposite the push out portion for catching the rivet as the rivet is pushed out.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention generally relates to tools and methods for removing a rivet after it has been installed, and more specifically relates to a rivet removal tool and method which eliminates, or at least substantially reduces, the end load which must be applied to drill out a button and remove a rivet.  
           [0002]    Self-piercing rivets are used in many different applications in order to secure two or more work pieces together. When a self-piercing rivet is installed, it is pushed into engagement with the work pieces such that a portion of the rivet expands and the work pieces deform around the expanded portion of the rivet. The expanded portion of the rivet becomes effectively embedded or encapsulated in the work pieces, thereby securing the work pieces together. The deformation of the work pieces causes a protrusion, often referred to as a “button”, to form on the other side (i.e. the blind side) of the rivet, and the button includes the expanded portion of the rivet therein.  
           [0003]    Sometimes, it is desirable to remove a rivet after it has been installed. One example is when the work pieces have become misaligned, such as during the riveting process. Prior art practices of removing a rivet after it has been installed involve initially grinding off the button. Attempting to remove a rivet by first grinding of the button is undesirable for several reasons. The grinding operation often requires that a relatively substantial end load be applied to the button (i.e. to the grinder which engages the button). This may be very difficult to achieve in light of the position of the rivet and the particular application. Even if it is possible to grind off the rivet, it becomes very difficult to push out the rivet because of the uneven ground surface. Lining up of a push out tool to the ground rivet is done by sight, which may be difficult if the rivet is in a position that is hard to see. This may also distort the hole if not lined up properly making it less likely to put a rivet back in the hole. Additionally, if the grinder slips during the grinding, it may mar the work piece. Finally, the grinding causes dust to spray into the air. This is undesirable and may create a workplace hazard, especially if the dust which sprays into the air is toxic.  
         OBJECTS AND SUMMARY OF THE INVENTION  
         [0004]    A general object of an embodiment of the present invention is to provide a hand held device for drilling into a button, where the hand held device eliminates, or at least substantially reduces, the end load which must be applied to remove a rivet.  
           [0005]    Another object of an embodiment of the present invention is to provide a hand held device for removing a button without an end load being applied by the user.  
           [0006]    Another object of an embodiment of the present invention is to provide a method of removing a rivet, where the method provides that the rivet can be removed without spraying dust into the air.  
           [0007]    Briefly, and in accordance with at least one of the foregoing objects, an embodiment of the present invention provides a hand held device for drilling into a button on a work piece. The hand held device includes a handle which is configured to be actuated to effect clamping of the hand held device onto the work piece. Support structure is connected to the handle, and a drill bit is disposed on the support structure. The drill bit is configured such that the button which is created upon installation of a rivet into the work pieces can be drilled into using the drill bit. Preferably, the hand held device includes a depth adjuster member, such as an adjustable collar, which is disposed on the drill bit such that the depth to which the drill bit drills into the button can be adjusted. The support structure may be generally integral with the handle of the hand held device, or can be provided as separate tooling which is engageable with a conventional hand held clamping device. Preferably, the hand held device is configured to apply an end load to the drill bit, so the user need not do so.  
           [0008]    To remove the rivet from the work piece, the hand held device is clamped onto the work piece, a drill is engaged with a drill bit, and the drill is operated to cause the drill bit to drill a recess into the button. Then, the hand held device is un-clamped and removed from the work piece, and a compression tool is used to remove the rivet from the work piece.  
           [0009]    Specifically, a push out portion of the compression tool is engaged with the recess formed in the work piece to push the rivet out of the work piece and into a recess provided by the compression tool.  
           [0010]    To provide such a compression tool having a push out portion and a recess for catching the rivet, a pair of bits may be provided for engagement with the compression tool, wherein one bit provides the push out portion and the other bit provides the recess for catching the rivet.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The organization and manner of the structure and operation of the invention, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings, wherein like reference numerals identify like elements in which:  
         [0012]    [0012]FIG. 1 is a cross sectional view of a self piercing rivet positioned for installation into a work piece;  
         [0013]    [0013]FIG. 2 is a cross sectional view of an installed rivet;  
         [0014]    [0014]FIG. 3 is a perspective view of a drilling device which is in accordance with an embodiment of the present invention;  
         [0015]    [0015]FIG. 4 is a side-elevational view of the device shown in FIG. 3;  
         [0016]    [0016]FIG. 5 is a front-elevational view of the device shown in FIG. 3;  
         [0017]    [0017]FIG. 6 is a cross-sectional view of the drilling device shown in FIG. 3, taken along line  6 - 6  of FIG. 4;  
         [0018]    [0018]FIG. 7 is a cross-sectional view of the device shown in FIG. 3 along with a cross-sectional view of a rivet installed in a work piece;  
         [0019]    [0019]FIG. 8 is a cross-sectional view of the device shown in FIG. 3 along with a cross-sectional view of an installed rivet at an intermediate stage in the drilling process;  
         [0020]    [0020]FIG. 9 is a cross-sectional view of a portion of the device shown in FIG. 3, along with a cross-sectional view of a rivet installed in a drip rail;  
         [0021]    [0021]FIG. 10 is a cross-sectional view of a portion of the device shown in FIG. 3 along with a cross-sectional view of a rivet installed in a drip rail at a final stage of the drilling process;  
         [0022]    [0022]FIG. 11 is a cross-sectional view of a portion of the compression tool of the present invention along with a cross-sectional view of a rivet upon which the tool can be used;  
         [0023]    [0023]FIG. 12 is a cross-sectional view of a portion of the compression tool along with a cross-sectional view of a rivet to be removed from a work piece shown at an intermediate stage of the compression process; and  
         [0024]    [0024]FIG. 13 is a cross sectional view of a portion of the compression tool along with a cross-sectional view of a rivet which has been removed from a work piece shown at a further stage in the compression process.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    While the present invention may be susceptible to embodiment in different forms, there is shown in the drawings, and herein will be described in detail, an embodiment thereof with the understanding that the present description is to be considered an exemplification of the principles of the invention and is not intended to limit the invention to that as illustrated and described herein.  
         [0026]    The method and apparatus of the present invention is used to remove rivets which have been installed in work pieces. Typically, the method and apparatus of the present invention are used to remove rivets of the self-piercing type. FIG. 1 illustrates a typical self-piercing rivet  10  positioned for installation into a work piece  12 . Although the method and apparatus of the present invention can be used to remove rivets from a variety of work pieces, a particular application will be described herein. The work piece  12  shown in FIG. 1 is a drip rail which is used to divert water away from openings in a vehicle, for example, the opening around a window. The work piece  12  consists of three layers, the first layer or outside drip rail  12   a,  the second layer or inside drip rail  12   b  and the third layer or frame of the vehicle  12   c.  The first layer  12   a  includes an upwardly directed flange  13   a,  the second layer  12   b  includes an upwardly directed flange  13   b,  and the third layer  12   c  includes a downwardly directed flange  13   c.  The rivet  10  includes an enlarged head portion  14  and a stem portion  16 . A cavity  18  is provided within the stem portion  16 . The rear side  20  of work piece  12  abuts an anvil  22  which provides resistance upon installation of the rivet  10 . A recess  24  is provided in the anvil  22 . The recess  24  will receive a deformed portion of the work pieces upon installation of the rivet  10 . Installation of the rivet  10  will begin as the rivet  10  pierces the front side  26  of the work piece  12 .  
         [0027]    [0027]FIG. 2 illustrates the rivet  10  as installed within the work piece  12 . As shown in FIG. 2, upon installation, the rivet has pierced the front side  26  of the work piece  12 , the first layer  12   a  and the second layer  12   b.  The third layer  12   c  has not been pierced. As a result of the installation process, a button  28  has been formed which protrudes from the rear side  20  of the work piece  12 . Also, upon installation, the cavity  18  of the rivet  10  is filled with material from the work piece  12 .  
         [0028]    As described above, it may become necessary to remove the rivet  10  from the work piece  12 . In such situations, the apparatus and method of the present invention can be used to effectuate the removal of the rivet  10 . The method of the present invention uses two tools to remove the rivet  10  from the work piece  12 . First, a hand held device or drilling tool  30  (shown in FIGS.  3 - 10 ) is used to remove the button  28  of the rivet  10 , and then a compression tool  32  (shown in FIGS.  11 - 13 ) is used to eject the rivet  10  from the work piece  12 .  
         [0029]    As shown in FIG. 3, the drilling tool  30  generally includes a handle portion  34  and tooling or support structure  36 . The handle portion  34  includes a front handle portion  38  and a rear handle portion  40 . A front jaw member  42  extends from the front handle portion  38  and a rear jaw member  44  extends from the rear handle portion  40 . The front and rear handle portions  38 ,  40  and the front and rear jaw members  42 ,  44  can be, for example, of the type used with a hand-held clamping device, such as the hand-held tool commonly called a vise grips.  
         [0030]    A U-shaped front tooth  46  extends from the front jaw member  42  and a U-shaped rear tooth  48  extends from the rear jaw member  44 . The front tooth  46  includes an upper prong  50 , a lower prong  52 , and a recess  54  between the upper prong  50  and the lower prong  52 . The rear tooth  48  includes an upper prong  56 , a lower prong  58 , and a recess  60  between the upper prong  56  and the lower prong  58 . As shown in FIG. 4, the front tooth  46  is aligned with the rear tooth  48  such that the upper prong  50  of the front tooth  46  is aligned with the upper prong  56  of the rear tooth  48  and the lower prong  52  of the front tooth  46  is aligned with the lower prong  58  of the rear tooth  48 . A mouth  62  is provided between the front tooth  46  and the rear tooth  48 . The mouth  62  is enlarged as the front handle portion  38  and the rear handle portion  40  are moved away from each other. The mouth  62  is closed as the front handle portion  38  and the rear handle portion  40  are moved toward each other. A thumb screw  64  is provided for adjusting the drilling tool  30  on the work piece  12 . As the thumb screw  64  is turned in one direction the mouth  62  of the drilling tool becomes smaller and as the thumb screw  64  is turned in the opposite direction, the mouth  62  of the drilling tool becomes larger.  
         [0031]    As shown in FIG. 5, the support structure  36  includes a generally T-shaped first member  70  and a generally U-shaped second member  72 . The first member  70  includes the rear tooth  48 , a first pin support  74  extending from one side of the rear tooth  48 , a second pin support  76  extending from the opposite side of the rear tooth  48 , and a collar platform  78  extending from the rear side of the rear tooth  48 .  
         [0032]    The second member  72  of the support structure  56  includes a base  80 , a first arm  82 , a second arm  84 , a first spring plunger  86  and a second spring plunger  88 . The base  80  is generally parallel to the first and second pin supports  74 ,  76 . The first and second arms  82 ,  84  extend from either end of the base  80  and are generally perpendicular to the base  80 . The first spring plunger  86  is generally perpendicular to the first arm  82  and extends from the opposite end of the first arm  82  as the base  80 . The second spring plunger  88  is generally perpendicular to the second arm  84  and extends from the opposite end of the second arm  84  as the base  80 . In describing the tool  30  the term proximal will be used to describe items closest to the base  80  and the term distal will be used to describe items closest to the first member  70 .  
         [0033]    The first member  70  is connected to the second member  72 , through a first pin  90  and a second pin  92 . The first pin  90  extends through an aperture in the first spring plunger  86  and through an aperture in the first pin support  74 . The second pin  92  extends through an aperture in the second spring plunger.  88  and through an aperture in the second pin support  76 . Threads are provided on the surface of the apertures in the first and second pin support members  74 ,  76  which engage with threads on the surface of one end of each pin  90 ,  92 . Enlarged portions  91 ,  93  are provided on the opposite ends of each of the pins  90 ,  92  respectively. A first spring  94  is mounted around the first pin  90  and is seated between the the first spring plunger  86  and the enlarged portion of  91  of the first pin  90 . A second spring  96  is mounted around the second pin  92  and is seated between the second spring plunger  88  and the enlarged portion  93  of the second pin  92 .  
         [0034]    As shown in FIG. 6, an aperture  98  is provided in the center of the base portion  80  of the second member  72  of the support structure  36 . An aperture  100  is also provided through the collar platform  78  and the rear tooth  48  of the first member  70 . The aperture  98  is aligned with the aperture  100 . A sleeve  101  is positioned within the aperture  100  and has an enlarged portion  103  which extends beyond the aperture in the collar platform  78 . A drill bit  102  is mounted through the apertures  98 ,  100  and through the sleeve  101  such that the rear end of the drill bit  102  extends proximally through the aperture  98  and the cutting end of the drill bit  102  extends distally through the aperture  100 . A conical tip  108  is provided on the cutting end of the drill bit  102 . The diameter of the drill bit  102  is slightly larger than the diameter of the button  28  on the rear side  20  of the work piece  12  and the diameter of the apertures  98 ,  100  and the aperture through the sleeve  101  are slightly larger than the diameter of the drill bit  102 .  
         [0035]    A collar or depth adjuster  104  is mounted on the drill bit  102  between the base  80  of the first member  70  and the sleeve  101 . The collar  104  is designed to slide axially along the drill bit  102  between the sleeve  101  which abuts the collar platform  78  of the first member  70  and the base  80  of the second member  72 . The collar  104  can be, for example, a common split sleeve fastener. Once the collar  104  has been correctly positioned, the collar  104  is locked in place by tightening the split sleeve fastener. The collar  104  is used to adjust the distance the drill bit  102  can travel and therefore the depth of the hole to be drilled as will be described herein.  
         [0036]    The cutting end and conical tip  108  of the drill bit  102  extends through the aperture  100  in the rear tooth  48 . A chip removal slot  106  is provided in the rear tooth  48  for the removal of the drilling debris. The rear end of the drill bit  102  extends beyond the second member  72  of the support  36 .  
         [0037]    Use of the tool  30  begins by the setting a depth L to which the drill bit  102  will cut into the rivet  10 . The collar  104  is loosened to allow the drill bit  102  to be positioned within the drilling tool  30 . The distance the conical tip  108  of the drill bit  102  is positioned beyond the rear tooth  48  will determine the depth L to which the drill bit  102  will cut into the rivet  10 . Typically the drill bit  102  is positioned so that the button  28  is removed to a depth which leaves the button  28  generally flush with the rear side  20  of the work piece  12 .  
         [0038]    After the depth L is set, the collar  104  and the drill bit  102  are forced down to sleeve  101  by a pre-load spring force from springs  94 ,  96 . The pre-load spring force of springs  94 ,  96  further forces base  80  down against the collar  104  which, in turn, is forced down against the sleeve  101 , thus creating a positive stop between the collar  104  and the enlarged portion  103  of the sleeve  101 . The tool  30  thus generates a pre-load as the springs  94 ,  96  have a built in spring force which is present at each step of the rivet removal process, such that users do not have to supply an end load to the tool  30  to get the drill bit  102  to move forward.  
         [0039]    The jaw members  42 ,  44  of the drilling tool  30  are opened by opening the front and rear handle portions  38 ,  40 . The front jaw member  42  is positioned near the front side  26  of the work piece  12  and the rear jaw member  44  is placed near the rear side  20  of the work piece  12 . The drilling tool  30  is positioned so that button  28  created upon installation of the rivet  10  is positioned centrally within the aperture  100  and the drill bit  102  is centrally aligned with the button  28 .  
         [0040]    As shown in FIG. 7, the mouth  62  of the tool  30  is placed around the work piece  12  and the rear tooth  48  contacts the rear side  20  of the work piece  12  and the conical tip  108  of the drill bit  102  contacts an indentation in the button  28  to assist centering of the tool  30 . Pre-loading of the drill bit  102  generated by the springs  94 ,  96 , assists and maintains the centering of the drill bit  102  to the button  28  of the rivet  10 . As the drilling tool  30  is fastened on to the work piece  12 , the button  28  of the rivet  10  contacts the conical tip  108  of the drill bit  102  and the drill bit  102  is forced proximally. As the drill bit  102  is forced toward the user, the collar  104  pushes against the base  80  of the second member  72 , and first and second spring plungers  86 ,  88  compress the springs  94 ,  96 . Upon compression of the springs  94 ,  96  a gap  107  is provided between the collar  104  and the sleeve  101 . The compression of the springs  94 ,  96  provides an increased force to be released, over the pre-load force provided by the springs  94 ,  96 , which eliminates the need for an end load to be applied by the user.  
         [0041]    A drill  109  (a portion of which is shown in FIG. 7) is mounted to the rear end of the drill bit  102 . Preferably, the point of the drill bit  102  is sized to a diameter D 1 , which is slightly larger than the rivet body diameter which reduces the push out forces. When power is supplied to the drill  109 , the drill bit  102  will begin to rotate. As shown in FIG. 8, the conical tip  108  of the drill bit  102  contacts the button  28 , and the button  28  is removed from the remainder of the work piece  12  by the drilling action of the drill bit  102 . Debris from the drilling action exits through the chip removal slot  106  (see FIG. 5). As the drill bit  102  advances within the work piece  12 , the increased spring force of the springs  94 ,  96  is released and the second member  72  moves toward the first member  70 . The drill bit  102  and the collar  104  move with second member  72  as it advances toward the first member  70 , closing the gap  107  between the collar  104  and the sleeve  101 . The drill bit  102 , collar  104  and second member  72  will continue to advance until the gap  107  has been eliminated and the collar  104  contacts the sleeve  101 , which acts as a positive stop such that no further material can be removed from the rivet  10 . As a result of the drilling action, the conical tip  108  of the drill bit  102  forms a concave recess  110  in the work piece  12 .  
         [0042]    As shown in FIG. 9, when the drilling tool  30  is used in connection with a drip rail, the flange  13   a  is positioned within the recess  54 , and flanges  13   b  and  13   c  remain outside of the mouth  62  of the drilling tool  30 . The relative dimensions of the recess  54 , the upper prong  50  of the front tooth  46 , the upper prong  56  of the rear tooth  48  and the work piece  12  allow upper prong  50  to contact the front side  26  of the work piece  12  as the flange  13   a  is positioned within the recess  54 .  
         [0043]    The drilling tool  30  provides precise alignment of the drill bit  102  with the button  28  and provides for stabilization of the drill bit  102  with respect to the work piece  12 . The spring force provided by springs  94 ,  96  eliminates the need for end force to be applied by the user. This also reduces the risk of the drill bit  102  slipping off the button  28  and marring the work piece  12 . In addition, unlike the grinding process, the drilling process does not cause dust to spray into the air and therefore eliminates the risk of the user inhaling toxic dust particles.  
         [0044]    Preferably, the drill bit  102  will be positioned within the collar  104  so that upon release of the increased spring force and completion of the drilling process, the button  28  is flush with the rear side  20  of the work piece  12  as shown in FIG. 10. The diameter D 1  of the conical tip  108  is smaller than a flare diameter D 2  of the rivet  10  at the drilled depth. Upon completion of drilling, the stem  16  of the rivet  10  will be exposed and the concave recess  110  will be centrally located in the cavity  18  of the rivet  10 . This concave recess  110  will assist in aligning the compression tool  32  as will be described below. The drilling tool  30  is released from the work piece  12  by releasing the front handle portion  38  and the rear handle portion  40 .  
         [0045]    The compression tool  32  used to eject the rivet  10  from the work piece  12  will now be described. The compression tool  32  utilizes a conventional tool such as a compression riveter. For example, the compression/squeeze riveter (model number US114TA) sold by United States Industrial Tool &amp; Supply Company can be used along with the bits  130 ,  132  to be described below, to eject the rivet  10  from the work piece  12 . Additional information about the squeeze riveter sold by United States Industrial Tool &amp; Supply Company can be found at www.ustool.com.  
         [0046]    As shown in FIGS.  11 - 13 , the compression tool  32  includes a body  33 , a generally U-shaped first arm  112  and a generally U-shaped second arm  114 . The body  33  contains the components necessary to activate the first arm  112  and the second arm  114 . The first arm  112  includes a first end  116  and a second end  118 . The second arm  114  includes a first end  120  and a second end  122 . The first end  116  of the first arm  112  is joined to the first end  120  of the second arm  114  by a pin  124  which allows the arms  112 ,  114  to rotate relative to one another.  
         [0047]    As shown in FIG. 11, a pushing bit  130  is mounted to the first arm  112 . The pushing bit  130  includes an elongated mounting portion  134  and an elongated pushing end  136 . A conically shaped tip  138  extends from the pushing end  136 . The conically shaped tip  138  matches the recess  110  of the work piece  12  due to the conical tip  108  of the drill bit  102  which formed the recess  110 . The matching of the conically shaped tip  138  and the recess  110  assists and maintains the centering of the compression tool  32  so that the rivet  10  can be removed with little or no distortion to the hole in the work piece  12 . A passageway  126  is provided in the second end  118  of the first arm  112 . The mounting portion  134  is positioned within the passageway  126  and a spring is placed within a groove  140  on the mounting portion  134  and retains the pushing bit  130  within the passageway  126 .  
         [0048]    A catching bit  132  is mounted to the second end  122  of the second arm  114 . The catching bit  132  includes an elongated mounting portion  142  and an enlarged cup shaped catching end  144 . A catching recess  146  is provided within the catching end  144 . A passageway  128  is provided in the second end  122  of the second arm  114 . The mounting portion  142  is positioned within the passageway  128  and a spring is placed within a groove  148  on the mounting portion  142  and retains the catching bit  132  within the passageway  128 .  
         [0049]    To remove the rivet  10  from the work piece  12 , the work piece  12  is placed between the pushing bit  130  and the catching bit  132 . The work piece  12  is aligned such that the front side  26  of the work piece  12  is proximate to the catching bit  132  and the rear side  20  of the work piece  12  is proximate to the pushing bit  130 .  
         [0050]    As shown in FIG. 12, the tip  138  of the pushing bit  130  is placed within the recess  110  of the work piece  12  and the catching bit  132  is aligned such that the head  14  of the rivet  10  is aligned with the recess  146  of the catching bit  132 . As shown in FIG. 13, when the compression tool  32  is activated, the second end  118  of the arm  112  is driven toward the second end  122  of the second arm  114 . The pushing end  136  of the pushing bit  130  is then driven through the layers  12   c,    12   b,    12   a  of the work piece  12  and the rivet  10  is ejected from the work piece  12 . The ejected rivet  10  is captured within the recess  146  of the catching end  144 . As the rivet  10  is pushed out of the work piece  12 , an extremely high amount of energy is built up due to the fit between the rivet  10  and the work piece  12 , such that when the rivet  10  starts to move, the stored up energy is released and the rivet  10  is ejected from the work piece  12  with a great amount of force. Thus, it is important that the rivet  10  is captured within the recess  146  to prevent injury to the user or another individual standing by.  
         [0051]    Ejection of the rivet  10  from the work piece  12  using the compression tool  32  allows for efficient removal of the rivet without damage to the surfaces of the work piece  12 . Upon removal of the rivet  10 , the work pieces can be properly aligned and a new rivet can be installed.  
         [0052]    While an embodiment of the present invention is shown and described, it is envisioned that those skilled in the art may devise various modifications of the present invention without departing from the spirit and scope of the appended claims. For example, it is to be understood that the present invention can be used with a work piece with any number of layers or with a variety of shaped work pieces including simply flat work pieces. As shown in FIGS. 9 and 10 for example, the dimensions of the front tooth  46  and the rear tooth  48  can be modified to accept these various shaped work pieces. Also, for example the drilling tool  30  and the compression tool  32  could be adapted for automation rather than hand activated.