Abstract:
Apparatus for installing a rivet nut or the like having an intentionally threaded shaft wherein said apparatus includes a hydraulically geared power tool having an inner hydraulic fluid containing a chamber and a screw adapted to engage the threaded shaft of the nut wherein said power tool rotates said screw when actuated. A fluid outlet is coupled to the chamber and is coupled to a gauge controlled power supply, the power supply being fluidly coupled to the power tool whereby the power supply includes torque predetermining means for determining when a predetermined torque is placed on the screw, this stopping rotation thereof and resuming rotation in an opposite direction to withdraw the screw from the nut.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to power tool apparatus; and, more particularly, to a hydraulically actuated power tool and related apparatus used to install a rivet nut in a panel or the like.  
         [0003]     2. Related Art  
         [0004]     Power tools have been used for years to install rivet nuts in panel assemblies. The Aro Corporation of City of Industry, California manufactures and sells power installation tools for installing threaded inserts, such as rivet nuts, in panels or the like.  
         [0005]     Convention power tools rotate to install such nuts but break off the shafts of such nuts during installation. Other such tools require measurement of the shaft of the nut during installation, then adjustment of the power tool.  
         [0006]     There is a need for apparatus to install rivet nuts wherein, when a predetermined torque is reached during installation, the rotating tip of the power tool stops, then reverses rotation to unscrew the tip from the nut.  
       SUMMARY OF THE INVENTION  
       [0007]     It is an object of this invention to provide spin pressure power tool apparatus for installing rivet nuts.  
         [0008]     It is a further object of this invention to provide such apparatus wherein a predetermined pressure can be set and the tip of the tool stops when such pressure is reached.  
         [0009]     These and other objects are preferably accomplished by providing apparatus for installing a rivet nut or the like having a threaded shaft.  
         [0010]     The apparatus includes a hydraulic geared power tool having an inner hydraulic fluid containing chamber and a screw adapted to engage the threaded shaft of the nut wherein the power tool rotates the screw when actuated. A fluid outlet is coupled to the chamber and coupled to a gauge controlled power supply, the power supply being fluidly coupled to the power tool whereby the power supply determines when a predetermined torque is placed on the screw. Rotation of the screw is stopped, then thereof and resumes rotation in an opposite direction to withdraw the screw from the nut.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is an elevational view, partly in section, of the installation tool of the total assembly;  
         [0012]      FIG. 2  is an elevational view of the spin pressure power tool apparatus of the invention;  
         [0013]      FIG. 3  is an elevational view of a portion of the apparatus of  FIG. 2  showing the interior of the power pack assembly with the top plate removed for convenience of illustration;  
         [0014]      FIGS. 4 through 9  are detailed view of portions of the apparatus;  
         [0015]      FIG. 10  is an elevational view of a modification of the apparatus of  FIG. 3  showing the modification in a cutaway view;  
         [0016]      FIGS. 11 and 12  are views showing a portion of the tool of  FIG. 1  used to install a conventional rivet nut, shown partly in cross-section, using the apparatus of the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]     Referring now to  FIG. 1  of the drawing, a power tool  10  is shown which forms part of the apparatus of the invention. Tool  10  includes a handle portion encompassed by housing  111  which internally includes components manufactured and sold by Aro Corp., of Bryan, Ohio. Tool  10  is adapted from the air motor operated tools made by Aro Corp. Two such tools are Aro Model No. 8519 (pistol grip shown in  FIG. 1 ) and Aro Model no. 7359E1 (lever style to be discussed further hereinbelow). Thus, housing  11 , except as herein discussed, internally houses components made by Aro Corp. to pneumatically rotate head cap screw  12  of tool  10 . Such internal equipment in housing  11  includes the head section, motor section, and gearing section of tool  10  and forms no part of the invention other than as modified herein and in the environment set forth.  
         [0018]     Thus, again referring to  FIG. 1 , a threaded hole  13  is tapped into the interior of housing  11  providing fluid communication with hydraulic fluid chamber  11 ′, a conventional part of Aro housing  11 , and shown in dotted lines. A conventional pneumatic fitting  15  is threaded into hole  15  coupled to a trigger signal line  16  which, as will be discussed, is coupled to fitting  100  ( FIG. 2 ).  
         [0019]     Housing  11  also includes a conventional pneumatic fitting  17 ,  FIG. 1 , communicating with the interior of housing  11 , coupled to hydraulic tubing  18  which, as will be discussed, is coupled to fitting  98  ( FIG. 2 ). Housing  11  also includes a conventional exhaust stem  19  ( FIG. 1 ) coupled to exhaust tubing  20 . Both fitting  17  and stem  19  are mounted in apertures  21 ,  22 , respectively, in a mounting plate  23  and retained thereto by a retaining ring  24 .  
         [0020]     Tool  10  is trigger operated by a rocker trigger  25  internally coupled to the valve stems (not shown) operatively coupled to the internal motor (not shown) of tool  10  within housing  11 . If desired, the internal mechanism of housing  11  may be lever operated as provided in Aro Corp.&#39;s lever-style power installation tool Model No. 7359E1. Rocker trigger  25  may rotate the cap screw  12  in a forward or clockwise direction when in one position, as the “up” position, and rotate cap screw  12  in the reverse or counterclockwise direction when in the other or “down” position, as will be discussed.  
         [0021]     Cylindrical housing  26  is mounted to rear housing  11  and includes an internal chamber  27 . A piston  28  is reciprocally mounted within chamber  27 . A spring  29  is disposed between piston  28  and a stop  40  mounted in chamber  27 . A washer  30  is mounted within chamber  27  between stop  40  and shoulder  31 . Washer  30  is stopped in its rearward direction by abutment with a shoulder  31 . A shaft  32  extends through the middle of piston  28  rearwardly through a washer  33  retained to shaft  32  by a roll pin  34  then rearwardly to a hex portion  35  mounted in extension  36  having a reduced neck portion  37  rotatably mounted in the rotatable portion  38  of thrust bearing assembly  39 . A stop  40  is provided in chamber  27  abutting at its forward end against a shoulder  41  on the inner wall of chamber  27  and at its rear abutting against an adapter  42  at the terminal end of housing  26  retained therein by groove pins  43 ,  44 . A spring  93  is encircles shaft  32  abutting at one end against washer  33  and at the other end against hex portion  35 .  
         [0022]     Piston  28  has a cavity  45  with a spring  46  mounted in cavity  45  surrounding shaft  32  and abutting at its rear end against shoulder  31 .  
         [0023]     An outer tube  47  is mounted to mounting plate  23  by means of an apertured guide  48  extending into an opening  49  in plate  23  receiving tube  47  thereon. A groove pin  50  retains tube  47  to guide  48  angled portion  52  having a conventional quick release hydraulic fitting  53  at the terminal end thereof coupled to fitting  96  ( FIG. 2 ). Tubes  47  and  51 , extending through outer tube  47 , are coupled ( FIG. 1 ) to housing  26  by means of an elbow  54  having a spring biased portion  55  mounted inside of the upper end of tube  47  receiving tube  51  therethrough. tube  51  has an elbow  54  is threaably mounted at its upper end  56  in a threaded opening  57  in housing  26 . Tube  51  has an angled upper portion  58  coupled thereto mounted in end  56  opening into communication with a fluid inlet  59  communicating with the interior of chamber  27 . A conventional O-ring  60  surrounds piston  28  mounted in an annular groove  61  therein.  
         [0024]     Piston  28  has a forward reduced neck portion  63  extending to and through a forward housing  64  detachably mounted to housing  26  as will be discussed. A pair of grooves  65 ,  66  are provided in the inner wall  67  of housing  26  surrounding piston portion  63 . A conventional O-ring  68  is mounted in groove  65  and a conventional backing ring  69  is mounted in groove  66 , both encircling piston neck portion  63 .  
         [0025]     A set screw  68 ′ having a slotted head  69 ′ is mounted in a stepped opening  70  in housing  26 . A conventional O-ring  71  surrounds the reduced neck portion  72  of screw  68 ′.  
         [0026]     A quick release sleeve  73  encircles a reduced diameter end  74  of housing  26  retained thereto by groove pin  75 . A ball bearing assembly  76  is provided in groove  77 , the ball thereof engaging the interior of sleeve  23 . An O-ring  91  is provided between sleeve  73  and shoulder  92  of housing  26 .  
         [0027]     Housing  64  tapers forwardly to terminal end  77 ′. Shaft  32  abuts against a shaft portion  78  extending into a hex-shaped nut  79  terminating in a hex head  80 . A roll pin  81  retains shaft portion  78  to nut  79 .  
         [0028]     Nut  79  is disposed in a cavity  82  formed in a cover  83 . A cap screw  12  extends through opening  85  in cover  83  with washer  86  surrounding the same. A hex-shaped end  87  closes off the forward end of housing  64 , head cap screw  12  extending therethrough. An insert  88  is disposed between hex nose piece  87  and screw  12  encircling screw  12 . Set screw  89  extends through a hole  90  in end  77 ′ of housing  64  securing nose piece  87  thereto.  
         [0029]     Referring now to  FIG. 2 , the tool  10  is coupled to a power pack  94 . Fitting  53  ( FIG. 1 ) is coupled, via tubing  95  to a quick connect fitting  96  in fluid communication with the interior of power pack  94  as well be discussed. Tubing  20  is coupled to a conventional muffler  20 ′. Tubing  18  extends to quick connect fitting  98  in fluid communication with the interior of power pack  94 . Tubing  16  extends to quick connect fitting  100  in fluid communication with the interior of power pack  94 . Suitable control dials  271 ,  256  to be discussed, are provided on the exterior of housing  106  of power pack  94 . Also, a pair of hooks  293 ,  294  may also be provided connected to housing  106  of power pack  94 .  
         [0030]     The interior of power pack  94  is shown in  FIG. 3 . Power pack  94  includes a rear cover  201  and a front cover  202  with interconnecting side plates  203 ,  204 . A pair of spaced internal partition walls  205 ,  206  are spaced from side walls  203 ,  204  respectively. Partition walls  205 ,  206  abut against and are supported at top and bottom by spaced hinges  207 ,  208 , respectively, curving upwardly at the sides of partition walls  205 ,  206 , as seen in  FIG. 3 . Hinges  207 ,  208  are bolted to cover  202  by suitable screws  209  and nuts  210 .  
         [0031]     Bushings  211 ,  212  interconnect partition wall  205  to side wall  203  whereas bushings  213 ,  214  interconnect partition wall  206  to side wall  204 . Screws  215  secure the bushings to their respective side walls.  
         [0032]     Bushing  211  extends through a hook spacer  216  with nut  217  on bushing  211  securing the spacer  216  in position. A like hook spacer  218  on the opposite side is secured in position by bushing  213  with nut  219  on bushing  213  holding spacer  218  in position. A pair of chest handles  220  are pivotally mounted on each side wall  203 ,  204  to hinges  221  fixed to their respective side walls by screws  222 . Handles  220  pivot outwardly to enable one to carry power pack  94 .  
         [0033]     Lower bushings  223 ,  224  are provided between side walls  203 ,  204  respectively and their respective partition walls secured in place by threaded inserts  225 .  
         [0034]     A support member  226  extends along the pack  94  between walls  203 ,  204  spaced from front wall  202  and secured to side walls  203 ,  204 , at each end respectively by screws  227 .  
         [0035]     It is to be understood that power pack  94  in  FIG. 3  may be normally closed by a top plate (not shown) extending between rear cover  201 , front cover  202 , and side walls  203 ,  204 . A back wall  228  closes off the back of power pack  94 .  
         [0036]     A conventional power booster  229  is mounted internally of power pack  94  connected to partition wall  205  by suitable nuts and bolts  200 .  
         [0037]     A conventional four-way valve  230  is also mounted internally of power pack  94  with a hollow tube  231  fluidly communicating at one end with valve  230  and at the other end with the space between partition wall  205  and side wall  203 .  
         [0038]     A male connector fitting  232  fluidly connects valve  230  to a pipe union  233  which is in turn fluidly connected to air filter, regulator and water separator apparatus  234 .  
         [0039]     A nipple  235  is fluidly connected to apparatus  234  fluidly coupled to elbow  236  which is fluidly coupled to ferrule  239  ( FIG. 4 ) coupled to the hose barb  237  via air house  238 . Hose barb  237  extends from regulator  240  and a nipple  241  fluidly couples regulator  240  to an elbow  242  fluidly coupled to a nipple  243 .  
         [0040]     Nipple  243  is in turn fluidly coupled to a cross fitting  244  (see also  FIG. 5 ) with bushing  245  ( FIG. 4 ) disposed between fitting  244  and elbow  242 .  
         [0041]     Cross fitting  244  ( FIG. 5 ) has a nipple  247  extending from one fluid outlet coupled to reducer adapter  246 . A swivel elbow  248  is fluidly coupled to another outlet of fitting  233  having tubing  249  fluidly coupled thereto. A third fluid outlet has nipple  250  fluidly coupled to a tee  251  having one outlet coupled to elbow  252  with tubing  253  in fluid communication therewith. A second outlet of tee  251  is fluidly coupled to a safety valve  254 . As seen in  FIG. 6 , cross fitting  244  is coupled to an elbow  255  of the hydraulic fluid reservoir  238 ′.  
         [0042]     The apparatus  234  ( FIG. 3 ) includes a liquid filled gauge  256  fluidly coupled thereto. Gauge  256  is coupled to power booster  229  ( FIG. 7 ) by an hydraulic tubing  257  extending at one end through a connector  258  to gauge  256  and at the other end to a tee  259  having one outlet  260  coupled to power booster  229  and the other outlet  261  coupled to an hydraulic tube  262 .  
         [0043]     The apparatus  234  includes a trigger valve  263  ( FIG. 7 ) coupled to a manifold  264 . Tubing  265  (see also  FIG. 8 ) is fluidly coupled to a connector  266  in fluid engagement with manifold  264 . A second tubing  267  is fluidly coupled to connector  258  ( FIG. 7 ) fluidly coupled to manifold  264 . A swivel elbow  269  ( FIG. 8 ) is fluidly coupled via tubing  270  to connector  266 .  
         [0044]     A gauge  271  ( FIG. 9 ) is coupled to apparatus  234  via a connector  272  fluidly connected at one end to apparatus  234  and at its other end coupled to tubing  273  extending to a connector  274  fluidly coupled to air gauge  271 .  
         [0045]     Air hose tubing  238  ( FIG. 4 ) extends from regulator  240  through an opening  275  in cover  202  to a quick connect/disconnect hose nipple  276  ( FIG. 3 ).  
         [0046]     A muffler  277  is coupled to an elbow  278  having a nipple  279  fluidly coupled to apparatus  234 . A keeper  280  is secured to back cover  228  by suitable screw and nut assemblies  281 ,  282 . A latch knob  283  extends from keeper  280  accessible from the exterior of front cover  202 . Rotation of knob  283 , coupled to front cover  202  via nut  285 , releases button  284  allowing removal of cover  202 .  
         [0047]     Tubing  262  is coupled via swivel elbow  286  to a manifold  287 . A like swivel elbow  289  couples tubing  267  to manifold  287 . Elbow  288 , coupled to tubing, is in fluid communication with a quick connect/disconnect pneumatic coupler  98  extending out of the front cover  202  of pack  94 . Elbow  289  is in fluid communication with a quick connect/disconnect pneumatic nipple fitting  100  extending out of the front cover  202  of pack  94 . Connection  286  is in fluid communication with a quick connect/disconnect hydraulic fitting nipple  96  extending out of the front cover  202  of pack  94 .  
         [0048]     Although a pair of carrying handles  220 ,  221  have been disclosed, as seen in  FIG. 10 , a pair of hooks  293 ,  294  may be provided for hanging power pack  200  on a supporting structure. Thus, each hook  293 ,  294  is pivotally connected via hex screw  295  and hex nut  296  between their respective outer side wall and an internal L-shaped flange  297  so that each hook  293 ,  294  may be pivoted to the position shown in  FIG. 10  for hooking the pack  94  on a supporting structure, then pivot the same back into pack  94  as seen in the dotted line position  294 ′.  
         [0049]     It is to be understood that air hose connector  276  ( FIG. 3 ) is adapted to be coupled to a suitable source of air (not shown).  
         [0050]     In operation, as seen in  FIG. 11 , the air motor (not shown) in tool  10  thus stalls or stops turning when flange  184  hits nose piece  87 . The trigger signal line  16  detects the stall of the air motor due to an increase in air pressure. That is, the air pressure goes up due to the trigger valve  263  ( FIG. 3 ) coupled to fitting  100  via line  267  (and, thus, to trigger line  16 ). A signal is sent from trigger valve  263  ( FIG. 8 ) via line  270  to main four-way valve  230 . Main valve  230  turns on and sends air to the air cylinder (not shown) via line  231 . This moves the piston (not shown) inside of power booster  229  forwardly, the rod of the piston moving to the left in  FIG. 3  or forwardly thus raising the pressure of the hydraulic cylinder  264  which raises the pressure in cylinder  264 . At the same time, hydraulic fluid from reservoir  238 ′ to hydraulic cylinder  264  and raises the pressure. The fluid flows out through fitting  96  via line  95  to fitting  53  to tool  10 . This moves the piston  28  in tool  10  rearwardly (backward) in  FIG. 1  which pulls the fastener  181  ( FIG. 11 ) backwards collapsing the same as seen in  FIG. 12 . This of course all occurs when trigger  25  is pressed in the “up” position. Trigger  25  is now pressed in the “down” position which threads cap screw  12  out of threaded engagement with fastener  181  shutting off the main valve  230 . This causes the piston inside of power booster  229  to move backwardly or the right in  FIG. 3  to its original position. This release the hydraulic pressure inside of cylinder  264  and the hydraulic fluid returns to reservoir  238 ′. This causes the return springs  29 ,  93  inside of tool  10  to push the piston  28  forwardly or to the left in  FIG. 1  when the pressure is released. When the trigger  25  is pushed at bottom, this creates a gap between flange  184  and the nose piece  87  reversing the screw  12  so it unthreads from fastener  181  ( FIG. 11 ).  
         [0051]     The operation of the air motor (not shown) in the tool  10  is conventional and the air supply via line  18  activated when the trigger  25  is pressed runs the air motor in forward and reverse directions as is well known in the pneumatic tool art.  
         [0052]     In operation, regulator gauge assembly  240  ( FIG. 3 ) is preset to the predetermined hydraulic pressure to be placed on the head cap screw  12  of the tool  10  of  FIG. 1  when installing a nut, such as the rivet nut  181  shown in  FIGS. 11 and 12 . That is, nut  181  is inserted into a hole  182  in a panel  183 , the enlarged head  184  thereof abutting against the outer surface  185  of panel  183 . Screw  12  is disposed in threading engagement with the inner threaded shank  186  of nut  181 . A predetermined torque on screw  12 , when installing nut  181 , will tell the operator that the nut  181  is properly installed as shown in  FIG. 12 . That is, the exterior surface  187  bulges up when a predetermined torque is reached when flange  184  hits nose piece  87  forming bulge  188  which deforms up against the panel  183  thus locking nut  181  to panel  183 . This torque is preset using regulator gauge  240 .  
         [0053]     Trigger  25  is thus pressed in the up position actuating the hydraulical gearing mechanism of pistol  10  thereby rotating screw  12 . Screw  12  will spin clockwise within nut  181  until it seizes up and the fluid pressure changes internally within pistol  10 . The nut shank  186  bulges up against the panel  183  to hold the rivet nut  181  to panel  183 . Trigger  25  is now pressed, in the down position, to rotate in a counterclockwise direction to remove the same from nut  181  (see  FIG. 12 ).  
         [0054]     Although a particular embodiment of the invention is disclosed, variations thereof may occur to an artisan and the scope of the invention should only be limited by the scope of the appended claims.