Abstract:
A rotating adapter for joining an offset, right angle, or other pulling head to a pulling tool. The adapter allows one-handed positioning of a pulling head that is offset, oriented at an angle relative to the tool, or designed to fit into a relatively tight space. The pulling head can be rotated and/or repositioned repeatedly without changing the stroke length of the pulling tool.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to an adapter for connecting a pulling head and a pulling tool for use to install fasteners, and more particularly to an adapter having parts that are rotatable with respect to each other. 
     BACKGROUND OF THE INVENTION 
     Fasteners used in aircraft and other industrial applications include blind rivets, blind bolts, lock bolts, and similar fasteners. These fasteners normally are inserted through prepared holes in work pieces that are to be joined to each other and installed in a manner that presses the work pieces together to ensure that there is no relative motion between the work pieces after the fasteners are installed. Generally, these fasteners are installed using a hydraulically activated gun or pulling tool that applies a tensile force to one part of the fastener and a compressive force to another part. A pulling head, operative to transmit both the tensile and compressive forces to a particular type and size of fastener, is attached to the gun or tool. 
     Often, a single gun or tool can be used with a variety of pulling heads to install a variety of fasteners. An adapter is used to join the pulling head to the tool or gun. Typically, an adapter is a tube or sleeve and an accompanying shaft, with each having screw threads on one end mateable with threads on the tool or gun and screw threads on the other end mateable with threads on the pulling head. 
     In use, it is often necessary to use an offset head with the pulling axis of the head displaced laterally from but parallel to the pulling axis of the tool, a right angle or other angled head with the pulling axis oriented at an angle other than parallel relative to the tool, or a straight pulling head for special use designed to fit into a relatively tight space. In these cases, the position of the head must be shifted or rotated relative to the tool to place fasteners in different locations, for example, above or below the shoulder of the installer or to one side or the other of the installer. Such repositioning of the pulling head relative to the tool is presently accomplished by loosening the jam nut on the pulling head, then rotating the head, and then locking the jam nut. The threads used to connect the draw bolt of the pulling head to the puller shaft of the adapter usually have a different pitch than the threads used to connect the outer portion of the pulling head to the outer sleeve of the adapter. Thus, each time the head is rotated for use in a different orientation, the positions of the draw bolt and the adapter puller shaft and the positions of the outer portion of the pulling head and the outer sleeve of the adapter are shifted relative to each other along the lengthwise axis of the tool. After a few reorientations, the tool can become inoperative because the relative axial positions of the draw bolt and puller shaft in relation to the axial positions of the outer portion of the head and the outer sleeve of the adapter do not allow the full range of relative axial motion needed to install a fastener. As a result, the pulling head often malfunctions. The position of the draw bold relative to the puller shaft, and the position of the outer portion of the head relative to the outer sleeve of the adapter, usually cannot be detected by looking at the assembled tool and pulling head. If a malfunction occurs, and the tool/head assembly is not damaged, the tool/head assembly must be fully disassembled and then reassembled by the operator, who must insure that all threaded parts are attached properly in accordance with industry standards. 
     The frequent loosening and tightening of the adapter relative to the pulling tool and the pulling head causes excessive wear on the complete assembly, requiring repairs to or replacement of the pulling tool, the pulling head, or the adapter. Further, repositioning the pulling head relative to the tool takes significant time, which reduces productivity. In addition, workers who use the tools and pulling heads are prone to repetitive use injuries from the frequent repositioning of the pulling head relative to the tool. 
     Thus, there is a need for an improved adapter that reduces tool wear, decreases the time required for repositioning the pulling head relative to the tool, and reduces the likelihood of repetitive motion injuries to workers using the tool. 
     SUMMARY OF THE INVENTION 
     To achieve the foregoing and other objects and in accordance with the purpose of the present invention broadly described herein, one embodiment of this invention comprises an adapter for joining a pulling head to a fastener installation tool, wherein the tool includes an outer portion for applying compressive force and a puller shaft slidable axially and reciprocally within the outer portion for applying tensile force, and the pulling head includes an outer portion for applying compressive force to a workpiece and a draw bolt for applying tensile force to a fastener, with the draw bolt slidable axially and reciprocally over a stroke length within the outer portion. The adapter comprises a sleeve assembly having a proximal portion mateable with the outer portion of the fastener installation tool and a distal portion mateable with the outer portion of the pulling head. The adapter also comprises a puller shaft assembly having a proximal portion mateable with the puller shaft of the fastener installation tool and a distal portion mateable with the draw bolt of the pulling head. The sleeve assembly and the puller shaft assembly share an axis, and the puller shaft assembly is slidable reciprocally along the axis within and relative to the sleeve assembly. The distal portion of the sleeve assembly is rotatable relative to the proximal portion of the sleeve assembly about the axis, and the distal portion of the puller shaft assembly is rotatable relative to the proximal portion of the puller shaft about the axis. The distal portions of the sleeve assembly and the puller shaft assembly are simultaneously rotatable about the axis repeatedly without changing the stroke length of the tool. 
     The adapter may further comprise a friction device for providing controlled rotation of the distal portion of the adapter sleeve assembly about the axis. The friction device may selected from single wave spring washers and multiple wave spring washers. The sleeve assembly may be mateable with the outer portion of the tool and/or the outer portion of the pulling head via screw threads. Also, the puller shaft assembly may mateable with the puller shaft of the tool and/or the draw bolt of the pulling head via screw threads. The sleeve assembly may further comprise a cap nut for holding the distal portion of the sleeve assembly adjacent the proximal portion of the sleeve assembly. The sleeve assembly and the puller shaft assembly are preferably operative to transmit forces to the pulling head sufficient for installing metal fasteners to the pulling head. The forces may be compressive and tensile forces up to about 12,000 pounds per square inch. The adapter may include a through hole in the sleeve assembly alignable with an opening in the puller shaft assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where: 
         FIG. 1  is a side view of one embodiment of a rotating adapter in accordance with the present invention; 
         FIG. 2  is a view of the adapter of  FIG. 1  from the end that attaches to a pulling head; 
         FIG. 3  is a side view of the rotating sleeve assembly of the adapter of  FIG. 1 ; 
         FIG. 4  is a side view of the puller shaft assembly of the rotating adapter of  FIG. 1 ; 
         FIG. 5  is a partial cross sectional view of the rotating adapter of  FIG. 1  along line A-A; 
         FIG. 6  is an exploded partial cross sectional view along line A_A of the rotating adapter of  FIG. 1 ; 
         FIG. 7  is a side view of another embodiment of rotating adapter, attached to a pulling tool and a pulling head, in accordance with the present invention; 
         FIG. 8  is a view of the adapter of  FIG. 7  from the end that attaches to a pulling head; 
         FIG. 9  is a side view of the rotating sleeve assembly of the adapter of  FIG. 7 ; and 
         FIG. 10  is a side view of the puller shaft assembly of the rotating adapter of  FIG. 7 . 
     
    
    
     DESCRIPTION 
     The present invention comprises an adapter for joining a pulling head to a fastener installation tool or pulling tool. The adapter has a puller shaft and a sleeve that are rotatable relative to each other about a longitudinal axis, allowing the attached pulling head to be rotated relative to the installation tool without disturbing the axial range of motion of either the pulling tool or the pulling head relative to one another. Both the tool and the pulling head are affected by the range of motion of their component parts. If the threaded components are not in their proper relationship, either the tool, the pulling head, or both will be out of adjustment, thus affecting the range of motion of the assembly. 
     A friction device within the present invention allows a user to rapidly position or reposition the pulling head as desired and then holds the pulling head in that desired position until the fastener installation is complete. The friction device within the present invention is capable of holding the attached pulling head in any position set by the user, without the user having to hold the pulling head in position. As a result, fasteners can be installed using a single hand by the user to operate the pulling tool, while his free hand can hold the work piece, which is often required. The adapter can be used with commercially available and commonly used installation tools, tool extensions, and pulling heads that require rotational positioning relative to the tool. Such heads include offset pulling heads, angled pulling heads, chisel point pulling heads, and other straight pulling heads. 
     In the following discussion, the terms “proximal” and “distal” are used with reference to the pulling tool to which the adapter would be attached. “Proximal” refers to the portion of the adapter or adapter component closest to the tool, and “distal” refers to the portion of the adapter or adapter component farthest from the tool. 
     Referring to  FIGS. 1-6 , one embodiment of the rotating adapter  100  comprises an outer rotating sleeve assembly  102  ( FIG. 3 ) and a puller shaft assembly  104  ( FIG. 4 ) disposed within and concentric with the sleeve about a longitudinal axis. Rotating sleeve  102  has a base  110  with a proximal end  112  with external screw threads  114  for joining the sleeve to the outer portion of a pulling tool (not shown). The distal end  116  ( FIGS. 5 &amp; 6 ) also has external screw threads  118 . A base flange  120  is between the screw threads  114  and  118 . The interior portion  120  has a smaller inner diameter portion  124  adjacent the proximal end  112  and a larger inner diameter portion  126  adjacent the distal end  116 , with a shoulder  128  between the narrower and wider portions  124  and  126 . Adapter  100  is suitable for use with CherryMax® pulling tools and heads. 
     Rotating adapter sleeve  130  has a proximal end  132  with an outer diameter sized to fit inside the distal end portion  126  of the outer sleeve base  110 , a distal end  134  with a smaller internal diameter, and a shoulder  136  stepping the internal diameter between the proximal and distal ends. Shoulder  136  has a reduced inside diameter to accommodate the threads on Cherry Max pulling heads that are attached to the distal end  134  of the sleeve assembly. External flange  138  is positioned between proximal end  132  and distal end  134 . Distal end  134  has internal screw threads  140  for engagement with the outer sleeve of a Cherry Max pulling head (not shown). Sleeve  130  also has flat portions  142  on its exterior surface to provide for engagement with a wrench or similar tool to install the pulling head onto the sleeve assembly. 
     A friction device  150  fits around the distal exterior of sleeve  130  and is positioned against external flange  138 , located between proximal end  132  and distal end  134  of the sleeve. The friction device  150  is preferably a multiple wave washer. More preferably, the friction device is a 3-wave washer having a load rate sufficient for the friction requirement. 
     Rotating adapter cap nut  160  has a proximal end  162  and a distal end  164 , with a shoulder  166  stepping between a larger inner diameter adjacent proximal end  162  and a smaller inner diameter adjacent distal end  164 . Internal screw threads  168  adjacent proximal end  162  are mateable with external screw threads  118  on the base  110 . With screw threads  168  and  118  mated, adapter sleeve is held between base  110  and cap nut  160 , and wave washer is held between shoulder  166  and flange  138 . 
     Puller shaft holder  170  has a proximal end  172  and a distal end  174 . Internal screw threads  176  adjacent proximal end  172  mate with a puller shaft of a pulling tool (not shown). Shaft holder  170  also has a flange  178 , sized to fit within the wider internal diameter proximal portion of adapter sleeve  130 , and an internal shoulder  180 . 
     Puller shaft  190  is slidable axially relative to shaft holder  170 . Shaft  190  has a proximal end  192  sized to slide axially within shaft holder  170 , with the motion stopped distally by internal shoulder  180 . A central portion  194  extends distally outward from shaft holder  170  and terminates in an externally threaded portion  196 . Threaded portion  196  is mateable with a pulling head drawbolt (not shown). Axial motion of puller shaft  190  relative to shaft holder  170  in the distal direction is limited when flange  198  adjacent proximal end  192  contacts shoulder  180  of the puller shaft holder  170 . 
     To utilize rotating adapter  100 , the puller shaft assembly  104  is first assembled. The distal end of puller shaft  190  is inserted into the proximal end of the puller shaft holder  170 , such that the threaded portion  196  extends beyond the distal end  174  of the puller shaft holder  170 . The combined puller shaft holder  170  and puller shaft  190  together make the puller shaft assembly  104 , and are attached to the puller shaft of a pulling tool. 
     The sleeve assembly  102  is assembled by inserting the proximal end  132  of sleeve  130  into the distal end  116  of sleeve base  110 , and then wave washer  150  is positioned over the distal end  134  of sleeve  130  and slid down against the distal face of flange  138  of sleeve  130 . The adapter cap nut  160  can now be positioned over the distal end  134  of sleeve  130  and slid down toward wave washer  150 , covering the washer with the larger inner diameter at the proximal end  162  until the shoulder  166  contacts the wave washer  150 . At the same time, the internal threads  168  of the cap nut  160  will contact the external threads  118  at the distal end of sleeve base  110 , and upon threading, the cap nut  160  will compress wave washer  150  against the distal face of flange  138  creating the desired friction for the designed operation of the rotating adapter assembly  100 . Preferably, a commercially available thread locking formulation is used in securing the threads of cap nut  160  to the threads of sleeve base  110 . 
     The sleeve assembly  102  is then placed over the puller shaft assembly  104  and threaded onto the exterior portion of the pulling tool. The resultant relationship between the distal end  196  of the puller shaft assembly  104  and the distal end  134  of the sleeve assembly  102  is dependent upon the design characteristics of the pulling head used in the completed assembly. Different pulling tools and different pulling heads being utilized with this present invention will determine the actual specifications required for each rotating adapter. 
     To attach a pulling head to the distal end of the adapter  100 , the screw threads on the end of the draw bolt of the pulling head are mated with threaded portion  196  of puller shaft  190 . Then the screw threads on the sleeve assembly of the pulling head are mated with screw threads  140  of rotating adapter sleeve  130 , using a wrench to engage flat portions  142  of the sleeve  130 . Both connections must be sufficiently tight that more force will be required to overcome friction for the connections to loosen than the force required to overcome friction caused by the wave washer  150 . 
     The rotating adapter of the present invention allows a user to lock both the draw bolt and the external portion of a pulling head to the puller shaft and external portion of a pulling tool via the rotating adapter assembly, so that the stroke length of the pulling head and the pulling tool are adjusted optimally for fastener installation. During use, both the sleeve  130  and the puller shaft  190  are rotatable with one hand about the longitudinal axis without any motion at the mated screw threads, thus maintaining the stroke length. The friction device  150  maintains the pulling head orientation in whatever position it is set to. During use, the distal face of flange  138  and friction device  150  are held tightly together by the cap nut  160  being threaded tightly to threads  118  on the distal end  116  of sleeve base  110 . A space between distal end  116  of sleeve base  110  and the proximal face of flange  138  is created because the length of the sleeve portion between the proximal face of flange  138  and the proximal end  132  of sleeve  130  is longer than larger diameter portion  126  at the distal end  116  of sleeve base  110 . This feature allows for compressive forces applied to the assembly during operation to travel down the sleeve  130  and be transmitted to the sleeve base  110 , and thus to the exterior portion of the pulling tool, without applying those forces to either the flange  138  or the friction device  150 , which are not exposed to the forces required to install fasteners. 
     Adapter sleeve  130 , by design of the present invention, is rotatable about the central axis to position any attached pulling head as desired relative to the tool, with friction device  150  preventing additional, undesired rotation in either direction. When puller shaft holder  170  is screwed onto the puller shaft of the pulling tool, puller shaft flange  198  is held against internal lip  180  of the shaft holder. The puller shaft assembly  104  slides axially within the adapter sleeve assembly  102  with the tool puller shaft, when the tool is actuated by the user. As the attached pulling head is positioned by the user, puller shaft  190  rotates about the axis relative to shaft holder  170  at the same rate that the adapter sleeve  130  rotates about the axis relative to the sleeve base  110 . 
     Another embodiment of a rotating adapter  200  is shown in  FIGS. 7-10 . Adapter  200  is similar to adapter  100 , except that it is suitable for use with Huck® pulling heads, such as pulling head  201  shown in dashed lines in  FIG. 7 , and pulling tools, such as pulling tool  203  shown in dashed lines in  FIG. 7 . Adapter  200  includes an outer sleeve assembly  202  and a puller shaft assembly  204 . 
     Outer rotating sleeve assembly  202  includes a sleeve base  210 , with an internally threaded proximal end  212  and an externally threaded distal end  216 . Jam nut  222  adjacent distal end  216  is knurled to aid in securing a pulling head  201  to the sleeve assembly  200 . Through hole  223  in rotating adapter sleeve  230  accommodates the end of a screw driver or other tool during attachment to a pulling tool or attachment of a pulling head. Flat portions  242  on adapter sleeve  230  accommodate a wrench or other tool. 
     Cap nut  260  secures sleeve  230  onto sleeve base  210 . Puller shaft  290  is slidable axially inside puller shaft holder  270 , like puller shaft  190  and puller shaft holder  170  in adapter  100 . Distal end  296  of puller shaft  290  is internally threaded and mateable with the draw bolt  291  of pulling head  201 . Proximal end  272  of shaft holder  270  is internally threaded for mating with the outer portion of a-pulling tool  203 . Flange  278  on puller shaft holder  270  includes an opening  282  that is alignable with opening  223  in adapter sleeve  230 . 
     Rotating adapter  200  can be assembled and mounted onto a pulling tool, such as tool  203 , in the same manner as rotating adapter  100 . To mount a pulling head, such as pulling head  201 , onto the adapter, the outer portion of the pulling head is screwed onto the externally threaded distal end  216  of adapter sleeve  230 . Puller shaft  290  is positioned so that holes  223  and  282  are aligned, and a screw driver, rivet stem, or other elongated tool is inserted into the holes to prevent relative rotation of the puller shaft and the adapter sleeve while the draw bolt  291  of the pulling head is screwed onto the internally threaded distal end  296  of puller shaft  290 . The screw driver or other tool is removed, and the assembled pulling tool  203 , adapter  200 , and head  201  are ready for use to install fasteners. 
     Repositioning pulling heads on pulling tools is a constant requirement in aircraft production and maintenance. Because the present invention prevents the stroke length from changing during use of an installation tool and pulling head, an aircraft mechanic or artisan using the adapter can focus on the work that needs to be done, for example, aircraft assembly or maintenance, and does not need to develop expertise in or spend time maintaining installation tools or removing improperly installed fasteners. The rotating adapter in accordance with the present invention makes aircraft construction and maintenance operations more efficient, because the tools operate reliably without becoming damaged, and the fasteners are installed properly. In addition, workers who use the tools and pulling heads are less prone to repetitive use injuries from the frequent repositioning of the pulling head relative to the tool, because the workers don&#39;t constantly loosen and tighten parts. 
     The rotating adapter of the present invention can be used with any combination of pulling tool and pulling head, as long as the proximal and distal ends of the sleeve and pulling assemblies are adapted for the specific tool and pulling head. The adapter can also be used with or incorporated into any extension for increasing the distance between the pulling tool and the pulling head. 
     The adapter may be formed from any material having suitable properties for formability, operation, and durability. Preferably, the material is an alloy suited to the design parameters. The outer sleeve assembly and the puller shaft assembly should be operative under forces commonly used to install fasteners used in aircraft and other industrial applications. Preferably, the adapter is able to transfer compressive and tensile forces up to about 12,000 pounds per square inch. 
     All threaded connections must be sufficiently tight that more force will be required to overcome friction for the connections to loosen than the force required to overcome friction caused by the wave washer or other friction device retained between the sleeve and the cap nut. 
     The foregoing description is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and process shown and described above. Accordingly, all suitable modifications and equivalents may be resorted to falling within the scope of the invention.