Abstract:
A portable rivet setting system is provided with a modular design. The portable rivet setting system includes an electronic control module, a pneumatic control module, a rivet feeder device, an escapement mechanism and an umbilical assembly including a rivet setting tool each modularly designed. The modular design improves the ability to react to diagnosed problems and allows the replacement or substitution of a single module while the faulty module can be repaired. The easy replacement or substitution of a module greatly reduces the down time associated with repairing the rivet setting system and allows a user to remove and replace a module with limited technical capabilities.

Description:
This appln claims benefit of Prov. No. 60/105,074 filed Oct. 21, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     The present invention relates generally to riveting machines, and more particularly to a portable riveting system with an autofeed mechanism for automatically supplying rivets to an application tool and methods for operating the riveting system. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     A blind rivet comprises a tubular rivet body in which is mounted a mandrel having a head portion at the narrow end of the stem so that when the mandrel is pulled back in the rivet, it upsets the rivet. When pulling-back of the mandrel is resisted with a predetermined force, the mandrel breaks off. A riveter that operates with such rivets typically has a housing formed at its front end with an aperture through which the rivet mandrel is engaged. Within the housing is a chuck that engages tightly around the mandrel and an actuating mechanism or pulling head which pulls the chuck backwardly, thereby upsetting the rivet and breaking off the mandrel. 
     In rivet setting machines, the operator sets a rivet held in the nose of the rivet tool by pulling a trigger. The remaining spent mandrel is drawn through the tool and through a collection tube into a collection box. A proximity switch senses the spent mandrel just before it enters the collection box. 
     There are a variety of different types of tools, both manual and powered, that are used to set pull-type blind fasteners. For industrial production, it is desirable to use a power tool that may have an air/hydraulic or electrical power assist to pull the mandrel stem. This facilitates the rivet setting operation. 
     It is known to automate the process of feeding rivets to the riveter tool, as for example shown in U.S. Pat. Nos. 4,754,643 and 4,747,294, commonly assigned. It is also known to automate the mandrel collection process as taught, for example, in U.S. Pat. No. 4,972,985, also commonly assigned. The most common approach to automatic rivet feed and disposal uses hydraulically or pneumatically powered mechanisms for guiding blind rivets to the riveting tool and extracting broken off mandrels therefrom. 
     Common shortcomings of prior art apparatus for autofeeding of rivets to the riveting tool is the failure of such systems to take into account the need for rapid adjustment, improved maintenance, serviceability and rapid change-over capability. In addition, ways are constantly being sought which speed up the reload capabilities as well as speeding up the rivet setting process. 
     In furthering the above and additional objects, the present invention provides a rivet setting tool including an automatic rivet delivery device for transferring a rivet from a rivet passage to a nose piece of the rivet setting tool. The rivet delivery device is air driven to extend forwardly of the nose of the setting jaws, and rotates to present a rivet in front of the jaws and then transfers the rivet into the jaws in known manner. The rivet delivery device extends through the rear of a hand tool so that its angular rotation can be adjusted without disassembling the tool. The stroke length of the rivet delivery device can also be easily adjusted. 
     A further feature of the rivet delivery device is the provision of a double-acting piston driven in both directions by positive air pressure to extend and rotate the delivery device in front of the nose piece and returning the rivet delivery device after rivet transfer. The use of a double-acting piston greatly enhances the speed at which the rivet delivery device can operate. Furthermore, the ability to adjust the stroke length or angular rotation of the rivet delivery device without disassembling the entire tool, greatly increases the ability to rapidly adjust the rivet delivery device in order to change over to different sized rivets or to simply make minor adjustments. 
     The system of the present invention also includes a portable housing and a hand tool connected to the portable housing. The portable housing includes electronic and pneumatic modules for controlling the supply of electric and pneumatic power to a rivet feeding device and to the hand tool. In response to the activation and release of a trigger switch on the hand tool, blind rivets are supplied from a feeder bowl via a track to a reciprocating escapement mechanism which transfers successive rivets from the track to a tube through which they are moved by compressed air to a rivet delivery device located on the hand tool. The different components of the portable autofeed riveting system are designed to be separately detachable from the housing as a modular unit so that the independent modular units can be easily disassembled from the housing and can be replaced by replacement modules so that the rivet setting tool experiences as little down time as necessary. 
     The portable rivet setting system of the present invention is also provided with an escapement mechanism which includes a nesting block slidably received by a housing and including a recessed portion for receiving and supporting a fastener therein. The nesting block can be easily changed in just a few seconds in order to accommodate a different sized rivet. The ability to rapidly change the nesting block reduces the amount of time required for change over, and thereby increases the efficiency of the overall riveting system. 
     The rivet setting tool of the present invention is provided with a pulling head which employs air pressure to return the piston to its full forward position and is connected to a remote intensifier via a hydraulic hose. The remote intensifier includes an air piston disposed in a piston chamber and a hydraulic ram connected to the air piston and extending into a hydraulic passage connected to the hydraulic hose. The air piston has a larger cross-sectional area than the hydraulic ram which allows the intensifier to generate a large hydraulic pressure from a relatively small air pressure. A first supply of pressurized gas communicates with a first end of the piston chamber and a second supply of pressurized gas communicates with a second end of the piston chamber. The second end of the piston chamber is vented to atmosphere around a piston chamber sleeve. The second supply of pressurized gas is utilized to provide a low pressure bubble of air on top of the air piston in order to assist the return of the piston of the pulling head to a retracted position while increasing the speed of the piston&#39;s return. The speed at which the air piston returns to its retracted position is directly related to the speed at which the rivet setting tool is reset in order to receive and set another rivet. 
     The rivet setting tool of the present invention is also provided with a control strategy whereby when a trigger is depressed, a controller instructs the remote pulling head back in order to set a rivet. The jaws engage the rivet mandrel and start the setting process. As hydraulic pressure builds, a high and a low pressure switch witness the increase in pressure as setting occurs, and set a latch. When the high pressure switch drops low again, the controller deduces that the rivet has set. Activation pressure to the remote intensifier is then stopped and return air is started causing the tools pulling head to return concurrently. The controller starts a mandrel collection window to monitor the collection of the mandrel. As the tool jaws open, the mandrel is released and a vacuum draws the mandrel past a mandrel sensor and into the collection bin. As the mandrel passes the mandrel sensor, the mandrel collection window is reset. The rivet delivery device loads a new rivet into the nose piece of a tool as the tool returns full forward. Since the high setting/loading speed makes it possible to have as many as two mandrels in the collection path at once, two separate mandrel collection windows are required, with the first becoming available for the third rivet as soon as the first mandrel passes the mandrel sensor. These two timers (windows) are continuously reused again and again throughout the process. If a jam were to inhibit collection of the mandrels as witnessed by the window timing out before the mandrel sensor detects a mandrel&#39;s passage, the system will shut down. 
     The pressure switches allow the system of the present invention to determine if there is a rivet loaded in the nose of the tool since no sensor is provided in the nose of the tool. During the setting process, the system confirms that a rivet has been loaded by monitoring the pressure switches. If the switches detect pressure within a short period of time, i.e., within an amount of time for the pulling head to travel almost fully back, it knows a rivet was presented and proceeds as above. If there were no rivet in the nose of the rivet setting tool, when the trigger is activated, the switches would see no build-up of pressure within the setting window and would not start a mandrel collection window, but would rather initiate the rivet delivery device reloading sequence. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is perspective view of an operator using the portable autofeed riveting system of the present invention; 
     FIG. 2 is perspective view of the portable autofeed riveting system of the present invention, illustrating the different modular components of the system according to the principles of the present invention; 
     FIG. 3 is a schematic view of each of the modules of autofeed riveting system of the present invention and showing the connections therebetween; 
     FIG. 4 is a perspective view from the right side of the rivet setting tool according to the principles of the present invention; 
     FIG. 5 is a perspective view from the left side of the rivet setting tool according to the principles of the present invention; 
     FIGS. 6-8 each provide a right side perspective view of a rivet setting tool according to the principles of the present invention with the rivet delivery device in three different operating positions, respectively; 
     FIGS. 9-11 are left side perspective views illustrating the rivet delivery device in three different operating positions, respectively; 
     FIG. 12 is a cross-sectional view of the rivet delivery device according to the principles of the present invention; 
     FIG. 13 is a partial sectional view of the cam sleeve of the rivet delivery device according to the principles of the present invention; 
     FIG. 14 is a cross-sectional view taken along line  14 — 14  of FIG. 12; 
     FIG. 15 is an end view of the piston of the rivet delivery device according to the principles of the present invention; 
     FIG. 16 is a side view of a rivet delivery device adjustment tool according to the principles of the present invention; 
     FIG. 17 is a perspective view of a feeder bowl and escapement mechanism according to the principles of the present invention; 
     FIG. 18 is a perspective view from a different angle of the feeder bowl and escapement mechanism shown in FIG. 17; 
     FIG. 19 is a perspective view of the escapement mechanism of the present invention with the top plate removed; 
     FIG. 20 is a perspective view of the escapement mechanism shown in FIG. 19 with the top plate disposed in its assembled position; 
     FIG. 21 is a top view of the rivet guide track and escapement mechanism according to the principles of the present invention; 
     FIG. 22 is a side view of the escapement mechanism according to the principles of the present invention illustrating the thumb screw for securing the top plate in its assembled position; 
     FIG. 23 is a perspective view of the nesting block of the escapement mechanism according to the principles of the present invention; 
     FIG. 24 is a side view of the nesting block shown in FIG. 23, illustrating the slot which receives the head of the driver rod according to the principles of the present invention; 
     FIG. 25 is a cross-sectional view of the remote intensifier according to the principles of the present invention; 
     FIG. 26 is a perspective view of the portable autofeed riveting system according to the principles of the present invention, illustrating the connections of the umbilical assembly of the present invention; 
     FIG. 27 is an illustration of a typical rivet set signature with the hydraulic pressure plotted over time and illustrating the window during which the detection of a mandrel is sensed. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIGS. 1-27, a detailed description of the portable autofeed riveting system  10  of the present invention will be described. The portable autofeed riveting system  10  includes a rivet setting tool  12  connected via an umbilical  14  to a portable housing  16  which houses a rivet feeder bowl  18  preferably of the vibratory type. The rivet feeder bowl  18 , best shown in FIGS. 17 and 18, is automatically fed rivets in bulk by a rivet hopper  20  which is disposed in a top portion of the housing  16  and is covered by a pivotally mounted cover  22 . Rivets delivered from the bulk supply in the vibratory bowl are stacked in an inclined feed track  24 , which accumulates a supply of rivets for escapement mechanism  26 . The rivet escapement mechanism  26 , which will be described in greater detail herein, includes a reciprocating nesting block  28  (see FIGS. 17-24) which periodically advances a rivet to a rivet delivery tube  30 . The rivet delivery tube  30  extends through umbilical  14  and delivers rivets, via pneumatic pressure, to the rivet setting tool  12  which will be described in greater detail herein. 
     The portable autofeed riveting system  10  also includes an electrical panel/module  34  to which are mounted key electrical components of the riveting system. Electrical control module  34  is connected to an external power source  35 . A pneumatic panel/module  36  is provided which supports key pneumatic components of the riveting system. The pneumatic control module  36  is connected to a main source of pressurized air  37  such as a compressor. The electrical panel  34  and pneumatic panel  36  are both supported by slots disposed in the bottom and top of the housing  16 . Electrical panel  34  includes a plurality of terminals which are engaged by electrical connectors which connect to the remaining components and modules of the riveting system  10 . A remote intensifier module  40  is provided in the housing  16  and provides hydraulic pressure through a hydraulic hose  42  which is disposed in the umbilical  14  and is connected to an installation tool including a pulling head  43  which engages a jaw case  44  for setting a rivet. 
     A barrier  46  is provided in the housing  16  for partitioning the housing  16  into two separate enclosed portions. The first enclosed portion houses the electrical and pneumatic panels  34 ,  36 , while the second portion houses the rivet feeder bowl  18  escapement mechanism  26 , rivet hopper  20 , remote intensifier  40 , and mandrel collection system  47 . The mandrel collection system  47  includes a collection bin  48  and a mandrel return tube  49  which is connected to the rivet setting tool  12  and receives a mandrel which is released by the jaw case of the rivet setting tool  12 . A mandrel sensor  50  is provided adjacent to the mandrel return line  49  for sensing the return of a mandrel into the mandrel collection system  47 . 
     An operator interface  56  is optionally mounted to the housing  16 , or if used in special applications such as with a workbench, can be pulled away from the housing  16  with a tether-like electrical cord  58 , as best shown in phantom in FIG.  2 . The operator interface  56  can be provided with a magnetized backing, a hook and loop-type fastener, or other known fastening systems, for supporting the operator interface to the housing  16  or to other surfaces such as a workbench or a cabinet. 
     The rivet setting tool  12  includes a rivet delivery device  60  as shown in FIGS. 3-12. The rivet delivery device  60  is mounted within a handheld housing  62  which includes a handle portion  64  with a trigger switch  66 . A grip strap  68  is mounted to the handle portion  64  and is adjustable in order to assist an operator in holding onto the rivet setting tool  12 . The grip strap  68  can be mounted on either side of the housing  62  as illustrated in FIGS. 4 and 5. 
     As best shown in FIG. 12, the rivet delivery device  60  includes a body tube  70  which receives a rod  72  which supports a delivery arm  74 . The rod  72  of rivet delivery device  60  is connected to a piston  76  which reciprocates within body tube  70 . The rod  72  has a threaded end portion  78  which is threadedly attached to an internally threaded portion  80  of the piston  76 . A piston stop member (cam actuator)  82  is provided with internal threads which engage threaded portion  78  of rod  72 . The rod  72  has a main body portion provided with a generally round cross-section with dual opposing flats (best shown in the cross-section view of FIG. 14) and is slidably received within a corresponding opening  86  which has a generally round cross section with dual opposing flats in a cam follower  88 . Cam follower  88  supports a pair of dowel pins  90  on opposite sides thereof which engage a cam slot  92  disposed in a radially outwardly disposed concentric cam sleeve  94 . Cam sleeve  94  includes an internal shoulder portion  96  which provides a seat portion for a coil spring  98  which is disposed between cam follower  88  and shoulder portion  96 . Spring  98  biases the cam follower  88  in the direction of arrow A as shown in FIG. 12 so that dowel pins  90  each engage an end of cam slots  92 . 
     The rivet delivery device  60  includes a rear cylinder cap  100  which is provided with a first fitting  102  which communicates with a piston chamber  104  through passage  106  for providing pressurized gas to the chamber  104  and thereby driving piston  76  in the direction of arrow B. A second fitting  108  is provided in the cylinder cap  100  which communicates via a passage  109  with a tube  110  which extends into a central passage  112  in rod  72 . An O-ring  113  is provided between the tube  110  and central passage  112 . A pair of pneumatic tubes  115   a,    115   b  (shown in FIG. 3) are connected to first and second fittings  102 ,  108 , respectively, for controllably operating the rivet delivery device  60 . As pressurized air is delivered through pneumatic tube  115   a  and first fitting  102 , the piston  76  is driven in the direction of arrow B whereby rod  72  extends out of the body tube  70 . As the piston stop  82  engages cam follower  88 , cam follower  88  presses against the bias of the spring  98 . As the dowel pins  90  follow the generally helical profile of the cam slots  92 , the cam follower  88 , and thus the rod  72  are caused to rotate. 
     With reference to FIGS. 6 and 9, the rod  72  and delivery arm  74  of rivet delivery device  60  are in the retracted position such as shown in the cross-sectional view of FIG.  12 . In the retracted position, a transfer bushing  114  which is provided in the end of delivery arm  74  is disposed opposite the receiver bushing  116  of the rivet delivery tube  30 . A suction pressure is applied through pneumatic tube  115   b  and second fitting  108  which provides a suction through central passage  112  in rod  72  which communicates with a passage  118  in delivery arm  74  which in turn communicates with a central passage  120  in transfer bushing  114 . The suction force retains the rivet R after the rivet is transported from the escapement mechanism  26  by the rivet delivery tube  30 . At this time, the suction force through second fitting  108  is maintained while pressurized gas is provided through first fitting  102  to cause piston  76  to slide along body tube  70  until piston stop  82  engages cam follower  88 . FIGS. 7 and 10 illustrate the orientation of the rod  72  and delivery arm  74  just as the piston stop  82  engages the cam follower  88 . At this time, piston stop  82  causes cam follower  88  to move relative to cam sleeve  94  against the biasing force of spring  98  so that the dowel pins  90  travel along generally helical cam slots  92  causing cam follower  88  and rod  72  to rotate relative to cam sleeve  94 , so that rod  72  and delivery arm  74  are oriented as illustrated in FIGS. 8 and 11. As the piston  76  reaches its fullest extended position, the rod  72  is fully extended and delivery arm  74  is rotated to be aligned with the nose piece  124  of the pulling adapter and jaw case mechanism  43 / 44 . A positive pressure is then induced through second fitting  108  to blow the rivet R across the gap into the nose piece  124  of the installation tool  43 / 44  where it is held in place by vacuum. 
     A third fitting  128  is provided in the rivet delivery device  60  and is connected to a pneumatic tube  130  (see FIG.  3 ). Third fitting  128  communicates with a second end of piston chamber  104  for providing pressurized gas to the second side of the piston  76  to force the piston  76  to its retracted position whereby the delivery arm  74  is again aligned with the receiver bushing  116  of rivet delivery tube  30  for beginning a reload cycle. 
     The rear cylinder cap  100  is provided with an O-ring  132  for sealing a first end of piston chamber  104 . The cam sleeve  94  is provided with a pair of O-rings  134  which sealingly close off the second end of piston chamber  104 . A front end cap  136  is provided in an open end of cam sleeve  94 . A TEFLON washer  138  and seal/seal sleeve assembly  140  are provided around the rod  72  within the open end of cam sleeve  94 . Piston  76  is provided with a magnetic ring  142  which works in combination with an external sensor (not shown) which senses the position of piston  76 . As the piston  76  returns to the retracted position, the external sensor sends a signal to the controller which then activates the escapement mechanism  26  to send another rivet to the tool. 
     The piston  76  is provided with a pair of bores  146 , as shown in FIG.  15 . The bores  146  are adapted to be engaged by a rivet delivery device adjustment tool  150  as shown in FIG.  16 . Adjustment tool  150  includes a cylindrical main body  152  and a handle  154  mounted to the main body  152  by a cap screw  156 . A pair of dowel pins  158  are inset in an end portion of main body  152 . In order to adjust the angular travel of rod  72 , cylinder cap  100  is removed from body tube  70  and adjustment tool  150  is inserted into the body tube  70  so that dowel pins  158  engage bores  146  of piston  76 . By rotating piston  76  relative to rod  72  via the adjustment tool  150 , the threaded engagement of the piston  76  to the rod  72  causes piston  76  to adjust the distance between piston stop  82  and piston  76 . The distance between piston stop  82  and piston  76  determines the angular travel of rod  72  and delivery arm  74 . Thus, the angular orientation of the delivery arm  74 , in the fully extended position, can be easily adjusted by simply removing cylinder cap  100  and adjusting the piston  76  using adjustment tool  150 . 
     In order to adjust the “throw” or distance of travel for the rod  72 , the piston stop  82  can be adjusted relative to rod  72 . In other words, by adjusting the threaded engagement between piston stop  82  and rod  72 , the distance between piston stop  82  and cam follower  88  is adjusted. This determines the “throw” of rod  72  and delivery arm  74 . Accordingly, in order to utilize the rivet delivery device  60  of the present invention with different sized rivets having different length mandrels, the “throw” of the rivet delivery device can be easily adjusted by pulling the cam sleeve  94  along with rod  72 , delivery arm  74  and piston  76  out from body tube  70  so that the piston stop  82  can be rotatably adjusted relative to the threaded portion  78  of rod  72 . The “throw” of the rivet delivery device  60  is adjusted when a changeover to a different sized rivet is required. Adjustment of the angular movement of the rod  72  and delivery arm  74  may be necessary if transfer bushing  114  of delivery arm  74  is not properly aligned with the nose piece  124  of the installation tool  126  in the fully extended rivet delivery position. It is anticipated that the rivet delivery device could be modified so that the “throw” could be adjusted in the manner that the angular travel is adjusted and the angular travel could be adjusted in a similar manner that the “throw” is adjusted in the embodiment as discussed above. 
     With reference to FIGS. 17-24, the improved escapement mechanism  26  of the present invention will now be described. Escapement mechanism  26  includes an escapement housing  170  which is mounted at a bottom portion of track  24 . A rivet nesting block  28  is slidably received in the escapement housing  170  and includes a recessed portion  172  for receiving and supporting a rivet R. Nesting block  28  is connected to a drive rod  174  which is connected to a piston (not shown) which is disposed in a pneumatic cylinder  176 . Drive rod  174  includes an end fitting  178  having a head portion which is received in an elongated slot  180  disposed in a side of the nesting block  28 . Slot  180  has a T-shaped cross section for receiving the head portion of end fitting  178 . Recessed rivet receiving slot  172  has a shoulder portion  182 , as shown in FIG. 23 on which the rivet flange rests, and a mandrel receiving slot portion  184  which receives a mandrel therein. The rivet receiving slot  172  and mandrel receiving slot  184  are each provided with a beveled edge portion  172   a,    184   a,  respectively. The beveled edge portions  172   a,    184   a  provide a camming surface to roll the second rivet in line out of the way and push it back up the track  24  as the nesting block  28  moves to a delivery position, thus preventing a jam in the escapement mechanism  26 . The nesting block  28  is removable from the escapement housing  170  as shown in FIG. 19 simply by lifting upward on the nesting block  28  so that the end fitting  178  of drive rod  174  is slid free of slot  180 . During a changeover, in order to utilize the escapement mechanism  26  of the present invention with different sized rivets, nesting blocks  28  having different sized rivet receiving slots  172  can be quickly and easily changed and connected to the end fitting  178  of drive rod  174 . 
     Nesting block  28  is secured within escapement housing  170  by placing a top plate  190  over escapement housing  170 . Top plate  190  includes a pair of holes  192  which receive locating pins  194  which extend upward from escapement housing  170 . Locating pins  194  hold top plate  190  in place as a thumb screw assembly  196  secures the top plate  190  to the escapement housing  170 . Thumb screw assembly  196  includes a swing bolt  197  pivotally mounted to the escapement housing  170  by a pivot pin  198 . Swing bolt  197  is received within a slot  200  disposed in a side of the top plate  190  and the thumb nut  202  is tightened downwardly onto the top surface of top plate  190 . 
     A clamp ring  204  is provided on the top plate  190  and surrounds an escapement guide tube  206 . The rivet delivery tube  30  is attached to the escapement guide tube  206  and held in place with clamp ring  204 . A source of pressurized air in the form of pneumatic tube  208  is provided in the bottom of escapement housing  170  which forces a rivet R which is in the rivet receiving slot  172  through rivet delivery tube  30 . The nesting block  28  is movable from a first loading position, wherein a rivet is received from track  24  and supported in the rivet receiving slot  172  of nesting block  28 . Cylinder  176  is then pressurized via pneumatic tube  210  (see FIG. 3) to force the drive rod  174  to move the nesting block  28  to a second, rivet delivery position, wherein the rivet receiving slot  172  communicates with the pneumatic tube  208  and the escapement guide tube  26  disposed on top plate  190  so that rivet R is delivered through rivet delivery tube  30 . Another source of pressurized gas communicates with cylinder  176  via pneumatic tube  211  (see FIG. 3) for returning the drive rod  174  and nesting block  28  to the hose or loading position. 
     During a changeover to a different sized rivet, or during cleaning or maintenance, the top plate  190  can be easily removed from escapement housing  170  by loosening thumb nut  202  and pivoting the swing bolt  197  away from the top plate  190  so the top plate  190  can be picked up off of escapement housing  170 . At this time, nesting block  28  can be removed by simply lifting upward on the nesting block  28  to disengage the nesting block  28  from the end fitting  178  of drive rod  174  as fitting  178  slides out of slot  180 . The rapid changeover, cleaning and maintenance capabilities which are provided by the improved escapement mechanism  26  enhances the efficiency of the riveting system of the present invention. 
     With reference to FIG. 3, the rivet setting tool  12  includes a pulling head  43  which includes a hydraulic piston  43   a  within a machined aluminum housing  43   b.  The piston is connected to jaw case  44  via a coupling so that during activation, i.e., hydraulic pressure supplied by a hydraulic hose  212  on the face of the hydraulic piston  43   a,  the jaws  44  ramp off a nose piece, and engage the rivet mandrel. Continued travel provides enough force and stroke to effectively set the average rivet. The pulling head  43  employs air pressure via pneumatic tube  214  on the opposite side of the hydraulic piston  43   a  to return the piston  43   a  to its full forward position once hydraulic pressure is removed. 
     The hydraulic supply hose  212  is connected to the remote intensifier  40 . As shown in FIG. 25, the remote intensifier  40  includes an intensifier chamber  220  which is provided with an intensifier chamber sleeve  222 . An air piston  224  is slidably received in the intensifier chamber  220  and is provided with a seal  226  which engages intensifier chamber sleeve  222 . A rod  228  is attached to air piston  224  and extends into a sealed cylindrical opening in a ram housing  230  which is filled with hydraulic oil  232 . A seal  233  is provided between the rod  228  and the housing  230 . A source of pressurized air in the form of pneumatic tube  234  is connected to a valve  236  which is connected to a quick dump exhaust valve  238  which communicates with a first end of intensifier chamber  220 . A second supply of pressurized air in the form of pneumatic tube  240  is provided in communication with a second end  242  of intensifier chamber  220 . A quick dump exhaust valve  244  is provided in communication with the second end  242  of intensifier chamber  220 . The ram housing  230  is connected to the hydraulic hose  212  by a plurality of fittings. 
     A high pressure hydraulic pressure switch  250  and a low pressure hydraulic pressure switch  252  are provided in communication with the hydraulic fluid passage  212 . Air pressure applied to the air piston  224  forces the rod  228  to displace a column of hydraulic oil  232  with a smaller cross-sectional area. The volume of air acting on the area of the piston forces the piston  224  and rod  228  upward. The differential in area between the air piston  224  and the top of the rod  228  allows the generation of a high hydraulic pressure from a low air pressure. 
     As the air piston  224  moves upward, exhaust dump valve  244  opens to vent air building up on top of the piston  224 . The high pressure column of oil  232  flows through the hydraulic hose  212 , and forces the hydraulic piston  43   a  of pulling head  43  back, thus setting the rivet. 
     Upon mandrel break, as detected by hydraulic switches  250  and  252  as described herein, the controller  34  stops activating the valve  236 , and starts activating a remote valve (not shown) supplying a regulated supply of air through quick dump exhaust valve  244  and on top of air piston  224 . The combination of the air behind the piston  43   a  of the pulling head  43  disposed within the rivet setting tool  12 , and the air bubble on top of the air piston  224  quickly returns the pulling head  43  and jaw case  44  to the retracted position. Return air on top of the air piston  224  cannot build up in pressure since the top or second end  242  of the chamber  220  is vented out around the intensifier chamber sleeve  222  and out to atmosphere. The sleeve  227  is provided with a plurality of recess portions  222   a  at an upper edge thereof forming vent passages. The chamber  220  is provided with a plurality of vent holes  220   a  in a lower portion thereof. The differential in the air flow entering the top of the chamber  220 , versus its ability to leak out past the sleeve  222  is what assists the air piston  224  in returning. Without venting the air in the upper portion of intensifier chamber  220 , it would be possible to supply too much pressure to the top of the air piston  224  which could draw the rod  228  out too fast, and force the introduction of air into the hydraulic passage past the seal  233 . The venting of the top portion  242  of the intensifier chamber  220  to atmosphere limits that possibility by limiting pressure build up. Air supply to the top of the air piston  224  is controlled by the riveting system controller  34  and shuts off after approximately one second. 
     In order to achieve a rapid loading and setting cycle, the remote intensifier design of the present invention provides a low pressure bubble of air on top of the intensifier piston  224  to assist the return of the entire system, and cut the return speed of the pulling head  43  of the installation tool  126 . By utilizing the intensifier  40  of the present invention, the return speed has been cut approximately in half in comparison to simply utilizing air pressure on the back of the piston of the pulling head  43  forcing the oil in front of the piston of the pulling head  43  back through the hose  212  and pressing air piston  224  back to its beginning position. 
     The rivet setting and mandrel collecting sequence of events is described with reference to FIG.  3 . When trigger  66  is depressed, the controller  34  activates the remote intensifier  40  to supply hydraulic fluid to the pulling head  43  to drive the pulling head  43  back. At the time the trigger  66  is depressed, the controller  34  starts a “rivet setting” window or time period. The jaw case  44  then engages the rivet mandrel and starts the setting process. As hydraulic pressure builds, the high and low pressure switches  250 ,  252 , respectively, witness the increase in pressure as setting occurs, and set a latch. When the high pressure switch  250  drops low again, the controller deduces that the rivet has been set. 
     FIG. 27 shows a typical rivet set signature wherein at time to activation of the trigger  66  begins a rivet setting sequence and a rivet setting window is started. At time t 1 , the mandrel is engaged by the jaws  44  and the hydraulic pressure begins to build low pressure. Low pressure switch  252  senses the hydraulic pressure rising above the low pressure limit P L  at time t 2  while the high pressure sensor  250  senses the hydraulic pressure climbing above the high pressure limit P H  at time t 3 . At time t 4 , the mandrel breaks and the hydraulic pressure rapidly drops and at time t 5 , the pressure drops below the high pressure limit P H  and is sensed by the high pressure switch  250  and the controller  34  deduces that the rivet has set. At this time, activation pressure to the remote intensifier  40  stops and return air is started, causing the tools pulling head  43  to return concurrently. The controller  34  starts a mandrel collection window to monitor the collection of the mandrel M. The time interval can be set, for example, at twenty-fifty percent longer than the nominal time for the mandrel to be fully released and collected (for example approximately three seconds for a typical mandrel collection time of two seconds). The tool jaws  44  open as the pulling head  43  returns and the mandrel M is released and a vacuum pressure draws the mandrel past the mandrel sensor  50  and into the collection bin  44 . As the mandrel passes the mandrel sensor  50 , the mandrel collection window is reset. The rivet delivery device  60  loads a new rivet into the nose piece  124  of the tool as the tool returns full forward. Since the high setting/loading speed makes it possible to have as many as two mandrels in the collection path at once, two (or sometimes more) separate mandrel collection windows are required. With two mandrel collection windows, the first mandrel collection window becomes available for a third rivet as soon as the first mandrel passes the mandrel sensor  50 . These two timers (or windows) are continuously reused again and again throughout the process. If a jam were to inhibit collection of the mandrels, this would be witnessed by the mandrel collection window timing out before the mandrel sensor  50  detects a mandrel&#39;s passage. With two mandrel collection windows, there could be as many as two mandrels in the path, but no more since this fault inhibits all setting functions until cleared and reset. 
     The rivet setting tool  12  uses no sensor to determine if there is a rivet loaded in the tool. The control system assumes the rivet device achieves loading on every attempt. It is during the setting process that this is proven true, or not, by monitoring the pressure switches  250 ,  252 . If the switches  250 ,  252  detect pressure within the riveting setting window, i.e., within an amount of time for the pulling head  43  to travel almost fully back (for example 40 ms), it knows a rivet was present and proceeds as above. If there were no rivet in the nose piece  124  when the trigger  66  is activated, the switches  250 ,  252  would see no build-up of pressure within the rivet setting window and would not start a mandrel collection window, but would rather initiate the rivet delivery device  60  reloading sequence. As compared with prior automated rivet setting systems which utilize a mandrel collection system, the control sequence of the present invention improves the speed of operation of the rivet setting system. With previous systems, the rivet setting tool was not allowed to reload until the previously spent mandrel is received past the mandrel sensor. However, with the present invention, it is possible to set a first rivet and to subsequently set a second rivet prior to the mandrel reaching the mandrel sensor associated with the mandrel collection system. Thus, the operator does not have to wait for the mandrel to be sensed before applying a second rivet. 
     Furthermore, with the control system of the present invention, once a mandrel break is detected, the supply of hydraulic pressure to the pulling head can be halted so that the pulling head can be immediately returned to its starting position, ready to begin another rivet setting sequence. Thus, the speed of operation of the rivet setting tool of the present invention is increased since the system does not have to wait any longer than necessary to reset itself after mandrel break is detected. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.