Abstract:
A rivet setting tool having a remote intensifier and autofill/recharge system is disclosed. The rivet setting tool has a hydraulic pulling head which is coupled to an intensifier. The intensifier has a means for providing hydraulic pressure to the hydraulic rivet head to set a rivet tool. The intensifier further has a mechanism for refilling/recharging the hydraulic system of the rivet setting head.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/422,555, filed on Oct. 29, 2002. The disclosure of the above application is incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    One field of the present invention relates generally to riveting machines and, more particularly, to a riveting system having a hydraulic remote intensifier with an auto-fill/recharge system and methods for operating the riveting system.  
         BACKGROUND OF THE INVENTION  
         [0003]    The present invention relates to a blind rivet comprising 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.  
           [0004]    In rivet setting machines, the operator sets a rivet held in the nose of the rivet tool by pulling a trigger. The remaining spend 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.  
           [0005]    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.  
           [0006]    It is known to automate the process of feeding rivets to the riveter tool, as for example shown in U.S. Pat. Nos. 6,240,613, 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.  
           [0007]    Common shortcomings of prior art apparatus for auto-feeding of rivets to the riveting tool is the potential of such systems to leak hydraulic fluid during maintenance, service and change-over. In addition, ways are constantly being sought which speed up the set-up capabilities as well as speeding up the rivet setting process.  
         SUMMARY OF THE INVENTION  
         [0008]    It is an object of the present invention to overcome the deficiencies described above. As such, what is disclosed is a rivet setting tool having a hydraulically driven pulling head for engaging a mandrel of a rivet and upon actuation, resetting the rivet. The rivet setting tool has a hydraulic pressure source coupled to the riveting head and an intensifier operably coupled to the hydraulic pressure source. A hydraulic refill system is coupled to the hydraulic pressure source which is configured to apply pressure to the hydraulic pressure source to cause the charging of the hydraulic system upon maintenance or refilling of the rivet setting head of the hydraulic system.  
           [0009]    In one embodiment of the present invention, a rivet setting tool is provided having a pulling head which has a hydraulic piston coupled to a rivet engaging jaw. A pneumatic intensifier defining a hydraulic pressure source is coupled to a hydraulic passage which is in turn coupled to the hydraulic piston. The hydraulic pressure source has a pneumatically actuated piston which is coupled to a rod which is slidably received within a ram housing. The ram housing is fluidly coupled to the hydraulic passage. The intensifier further has a baffle which divides an intensifier cavity into a hydraulic fluid source and a first cavity. The hydraulic fluid source is fluidly coupled to the ram housing when the rod is in a fill position and substantially fluidly sealed from the ram housing when the rod is in an actuation position within the ram housing. Application of air pressure to a first side of the piston causes hydraulic pressure to be applied to the hydraulic piston. Application of air pressure to a second side of the piston allows the rod to move from the actuation position to a filled position.  
           [0010]    In another embodiment of the invention, a rivet setting tool having a pulling head including a hydraulic piston is provided. An intensifier having a hydraulic pressure source is coupled to the hydraulic piston. The intensifier has a refilling mechanism which when actuated fluidly couples a source of hydraulic fluid to the hydraulic piston. The intensifier further has a means for applying hydraulic pressure to the hydraulic passage to actuate a rivet setting mechanism.  
           [0011]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0013]    [0013]FIG. 1 represents a system overview of the rivet setting system according to the teachings of the present invention;  
         [0014]    [0014]FIG. 2 represents a subassembly of the rivet setting system in its actuation position;  
         [0015]    [0015]FIG. 3 represents a view of the rivet setting system shown in FIG. 1 in its fill position; and  
         [0016]    [0016]FIG. 4 represents the recharging or filling of the hydraulic system. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0018]    With reference to FIG. 1, the fastening system  10  according to the present invention is shown. Shown is a rivet setting tool  12  operably coupled to an electronic controller  14 , hydraulic controller  16 , a pneumatic controller  18 , a rivet feeder  20 , a remote hydraulic intensifier  22 , and a mandrel collection system  24 .  
         [0019]    The rivet setting tool  12  includes a pulling head  44  which includes a hydraulic piston  46  within a machined aluminum housing  48 . The hydraulic piston  46  is connected to jaw case  50  via a coupling so that during activation, i.e., hydraulic pressure supplied by a hydraulic hose  52  on the face of the hydraulic piston  46 , the jaws  51  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  44  employs air pressure via pneumatic tube  54  on the opposite side of the hydraulic piston  46  to return the hydraulic piston  46  to its full forward position once hydraulic pressure is removed.  
         [0020]    The hydraulic supply hose  52  is connected to the remote intensifier  22 . As shown in FIG. 2, the remote intensifier  22  includes an intensifier chamber  56  which is defined within an intensifier chamber body  58 . An air piston  60  is slidably received in the intensifier chamber  56  and is provided with a seal  62  which engages intensifier chamber body  58 . A rod  64  is attached to air piston  60  and extends through a sealed cylindrical opening aperture defined through an intensifier chamber intermediate baffle  66  and into a cylindrical opening defined in a ram housing  68  which is filled with hydraulic oil  70 . A seal  72  is further provided between the rod  64  and the ram housing  68  which substantially fluidly separates the intensifier chamber  56  from a bore  67  defined by the ram housing  68 . A source of pressurized air in the form of pneumatic tube  74  is connected to a valve  76  which is connected to a first quick dump exhaust valve  78  which communicates with a first end of intensifier chamber  56 . A second supply of pressurized air in the form of a second pneumatic tube  80  is provided in communication with a second end  84  of intensifier chamber  56 . A second quick dump exhaust valve  82  is provided in communication through line  104  with the second portion  84  of intensifier chamber  56 . The ram housing  68  is connected to the hydraulic hose  52  by a plurality of fittings.  
         [0021]    Air pressure applied to the air piston  60  forces the rod  64  to displace a column of hydraulic oil  70  with a smaller cross-sectional area. The volume of air acting on the area of the piston forces the air piston  60  and rod  70  upward. The differential in area between the air piston  60  and the top of the rod  70  allows the generation of a high hydraulic pressure from a low air pressure. As the air piston  60  moves upward, first exhaust dump valve  78  opens to vent air building up on top of air piston  60 . The high pressure column of oil  70  flows through the hydraulic hose  52 , and forces the pulling head hydraulic piston  46  of pulling head  44  back, thus setting the rivet. During operation, should the fluid level become low, fluid flows through open hydraulic system port  59  to replenish the fluid supply within bore  67 .  
         [0022]    Upon mandrel break, the controller  16  stops activating the valve  76 , and starts activating a remote valve (not shown) supplying a regulated supply of air through quick dump exhaust valve  82  and on top of air piston  60 . The combination of the air behind the pulling head piston  46  of the pulling head  44  disposed within the rivet setting tool  12 , and the air bubble on top of the air piston  66  quickly returns the pulling head  44  and jaw case  50  to the retracted position. The venting of the second portion  84  of the intensifier chamber  56  to atmosphere limits that possibility by limiting pressure build up. Air supply to the top of the air piston  60  is controlled by the riveting system controller  14  and shuts off after approximately one second.  
         [0023]    [0023]FIG. 3 represents the system  10  of the present invention in its automatic refill mode. Upon actuation of the refill feature by an operator, the electronic controller  14  functions to prompt the operator to open the bleed screw  100 . After confirmation that a bleed screw  100  has been opened, the electronic controller  14  functions to send a signal to the pneumatic controller  18  to begin the refill process. Pneumatic pressure is now directly applied to a top surface  102  of the air piston  60  through pneumatic line  104 . In this regard, air pressure is supplied by a pneumatic line  104  to a first cavity  106  formed between the air piston  60  and the baffle  66 . Air pressure is applied so as to retract the rod  64  to a refill position  108 , so as to allow the fluid coupling of a hydraulic source  110  with the ram housing  68 .  
         [0024]    As shown, a check valve  88  is fluidly positioned between the hydraulic fluid source  110  and the bore  67  of the ram housing  68 . The check valve  88  is positioned at a proximal end  114  of the ram housing  68 . Additionally, the ram housing can define a second aperture (not shown) to fluidly couple the hydraulic fluid source  110  to the ram housing  68 . The second aperture can optionally have a check valve which allows the flow of hydraulic fluid from the fluid source  110  into the bore  67 , while closing the fluidly coupling between the ram housing bore  67  to the hydraulic source when the rivets are being set. The rod  64  and intermediate baffle seal  72  fluidly separate the first cavity  106  from the hydraulic fluid source chamber  112 .  
         [0025]    As seen in FIG. 4, once the bore  67  defined by the ram housing  68  is fluidly coupled to a source of hydraulic fluid  70 , air pressure is supplied directly through pneumatic line  80  by the pneumatic controller  18  so as to supply hydraulic oil  70  through the ram housing  68  and into the hydraulically actuated rivet setting tool  12  to charge the hydraulic lines. Differential pressure opens check valve  88  to fluidly couple the hydraulic fluid source  110  with the bore  67 . Specifically, pneumatic pressure is applied into the hydraulic fluid source chamber  112 , between an upper surface of the hydraulic fluid  70  and the top surface  116  of the hydraulic source chamber  112 . This pressure forces the hydraulic fluid through the check valve  88  located at the proximal end  114  of the ram housing  68  into the bore  67 .  
         [0026]    After sufficient hydraulic fluid  70  has escaped through the bleeder screw  100 , the operator stops the recharging cycle by pressing a button on the electronic controller  14 . The system  10  then applies pneumatic pressure to a bottom surface  120  of the air piston  60  through a pneumatic line  122  coupled to the bottom of the remote intensifier  22 . This returns the air piston  60  to its actuation position  122 , thus resetting the rod  64  into the ram housing  68  as shown in FIG. 2.  
         [0027]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.