Abstract:
A nut driver is provided in which a torque is delivered to a fastener while a bolt is rotationally maintained in a fixed position thereby tightening the fastener onto the bolt. The nut driver also removably attaches to pulse gun and includes a planetary gear arrangement. The nut driver is interchangeable with a variety of pulse guns. Although, conventional devices provide a torque to rotationally couple a nut to a bolt, the feature of interchangeability which allows utilization of different pulse guns is not available. The ability to interchange pulse guns allows the nut driver to easily be used with a variety of drive devices or pulse guns. Furthermore, the nut driver converts the variety of pulse guns into useful driving tools for fastening nut and bolts or other fastener pairs together.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a nut driver apparatus and more particularly to a nut driver attachment for use with a pulse gun which provides a drive torque to the attachment. 
     The tightening of a fastener or nut to a bolt often requires the application of a torque to the fastener while the bolt remains fixed. Drivers in popular use today are often combined as a unitary tool including a motor. Selection of different types of impact wrenches and hammer drills is therefore not possible without substituting the entire unit. Furthermore, conventional nut drivers that are configured for attachment to a drive spindle or power tool are limited in that they are integral with limited types of air impact wrenches and hammer drills. Consequently, there is a need for a nut driver which removably couples to a pulse gun. 
     Furthermore, traditional drivers often apply a torque to the fastener of a fastener and bolt assembly but do not control the position and movement of the bolt. The bolt is often freely positioned in a hole in which it rests. As a result the bolt may move or the torque may not efficiently tighten the nut to the bolt. This lack of control is detrimental in an environment in which it is desired to quickly tighten the fastener to the bolt. Consequently, there is a need for a nut driver which maintains control of the bolt as well as apply an adequate torque to the nut. Moreover, most conventional torque wrenches and drivers provide an undesirably strong “jerk” or sudden rotational force to the user during use. 
     SUMMARY OF THE INVENTION 
     In accordance with the teachings of the present invention, a nut driver is provided. In another aspect of the present invention, a torque is delivered to a fastener while a bolt is rotationally maintained in a fixed position thereby tightening the fastener onto the bolt. Yet another feature of the nut driver is that it removably attaches to pulse gun. In still another aspect of the present invention, the nut driver includes a planetary gear arrangement. 
     The nut driver allows a smooth rotation of the nut while significantly reducing “jerk-like” motions. The nut driver is also interchangeable with a variety of pulse guns. Although, conventional devices provide a torque to rotationally couple a nut to a bolt, the feature of interchangeability which allows utilization of different pulse guns is not available. The ability to interchange pulse guns allows the nut driver to easily be used with a variety of drive devices or pulse guns. Furthermore, the nut driver converts the variety of pulse guns into useful driving tools for fastening nut and bolts or other fastener pairs together. 
     Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 s a side elevational view showing the preferred embodiment of a nut driver of the present invention attached to a pulse gun; 
     FIG. 2 is an exploded perspective view, taken along line  2 — 2  of FIG. 1, showing the preferred embodiment nut driver; 
     FIG. 3 is a sectional view, taken along line  3 — 3  of FIG. 2, showing the preferred embodiment nut driver; 
     FIG. 4 is a cross-sectional view, taken along line  4 — 4  of FIG. 3, showing a drive gear and associated idler gears in an engaging arrangement along with a center socket employed in the preferred embodiment nut driver; 
     FIG. 5 is a cross-sectional view, taken along line  5 — 5  of FIG. 3, showing the preferred embodiment nut driver; and 
     FIG. 6 is a cross-sectional view, taken along line  6 — 6  of FIG. 3, showing an output gear and associated idler gears in an engaging arrangement, employed in the preferred embodiment nut driver. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 2, the preferred embodiment of a nut driver apparatus  10  of the present invention is interchangeably coupled to a pulse gun  14  which provides a pulse input torque to nut driver apparatus  10 . Nut driver apparatus  10  includes an input end  16  and an output end  18 . Input end  16  is coupled to pulse gun  14  via a gun coupler  20 . At the opposite end of nut driver apparatus  10 , output end  18  is coupled to a nut  26  via socket  22 . In this configuration, a threaded bolt  24  is engaged with a threaded nut  26 . 
     FIGS. 2 through 6 show nut driver apparatus  10  in further detail. Nut driver apparatus  10  may be used with any configuration in which it is desirable to torque or forcibly rotate a nut such that it fastens to a bolt. Nut driver apparatus  10  includes a housing  12 , gear system  42  and center socket assembly  74 . Housing  12  includes an input end cap  30 , housing body  32  and output end cap  34 . Input end cap  30  and output end cap  34  are coupled to housing body  32 . Input end cap  30  and output end cap  34  form input opening  38  and output opening  40 , respectively. Input opening  38  and output opening  40  are sized and shaped to rotatably support gears of gear system  42 . Housing  12  has a housing adapter  31 , for attaching to the pulse gun, but which prevents the housing from rotating. 
     Gear system  42  is disposed within housing  12 . Gear system  42  includes a drive gear  44 , idler gears  46 ,  48 ,and  50 , and an output gear  52 . Drive gear  44 , idler gears  46 ,  48  and  50 , and output gear  52  form a planetary gear system. Drive gear  44  includes a drive gear outer&#39;shaft  54 , drive gear teeth  56 , drive gear inner shaft  58  and drive coupling  59 . Drive gear outer shaft  54  forms a drive gear channel  55 . Drive gear teeth  56  are disposed between drive gear inner shaft  58  and drive gear outer shaft  54 . Drive gear teeth  56  engage with two of the idler gears at a time. Drive coupling  59  is coupled to drive gear inner shaft  58 . Drive coupling  59  is sized and shaped to couple with the pulse gun in a manner such that drive coupling  59  transmits an input torque to drive gear  44 . Needle bearings  60  and  62  are disposed on drive gear inner shaft  58  and drive gear outer shaft  54 . Drive gear  44  rotates within housing  12  through needle bearings  60  and  62 . Thrust bearing  64  is disposed between drive gear inner shaft  58  and input end cap  30  and thrust bearing  65  is disposed on drive gear outer shaft  54  to permit movement of drive gear  44 . Drive gear  44  transfers a pulsating torque to the gear system  42  from the pulse gun  14 . 
     Idler gears  46 ,  48  and  50  are substantially similar such that idler gear  46  will be described in detail. Idler gear  46  includes input idler gear  66 , output idler gear  68 , idler gear shaft  70  and idler gear spindle  72 . Input idler gear  66  and output idler gear  68  are coupled at a length provided by idler gear shaft  70 . Input idler gear  66  and output idler gear  68  are supported on opposite ends of idler gear shaft  70 . Idler gear shaft  70  forms a channel within which idler gear spindle  72  is disposed. Idler gear spindle  72  is rotatably supported at a first end within input end cap  30  and at a second end within output end cap  34 . Needle bearings  77  and  79  are coupled, at a first location, between input idler gear  66  and idler gear spindle  72  and, at a second location, between output idler gear  68  and idler gear spindle  72 . Output idler gear  68  mesh with output gear teeth  84  of output gear  52 . When input idler gear  66  selectively meshes with drive gear teeth  56  of drive gear  44 , idler gear shaft  70 , and thus output idler gear  68  rotates about needle bearings  77  and  79 . Thrust bearings  73  and  75  are disposed on either ends of idler gear spindle  72  to assist in distributing force. Idler gears  46 ,  48  and  50  transfer input drive plower to output gear  52 . 
     Output gear  52  includes an output gear outer shaft  76 , output gear teeth  84 , input gear inner shaft  80 , and output gear coupling  82 . Output gear outer shaft  76 , input gear inner shaft  80  and output gear coupling  82  form an output gear channel  86 . Output gear teeth  84  are supported between output gear inner shaft  80  and output gear outer shaft  76 . In the preferred embodiment, output gear teeth  84  engage with two of the idler gears at a time. Output gear coupling  82  is coupled to output gear inner shaft  80 . Output gear coupling  82  is sized and shaped to couple with socket  22  in a manner such that output gear coupling  82  provides an output torque to socket  22 , and therefore provides torque to nut  26  which fastens onto bolt  24 . Needle bearings  92  and  88  are disposed on output gear inner shaft  80  and output gear outer shaft  76 . Output gear  52  rotates within housing  12  through needle bearings  88  and  92 . Output gear  52  may be rotated in a clockwise or counter clockwise direction. Thrust bearings  90  and  91  are disposed on output gear inner shaft  80  and output gear outer shaft  76 , respectively. Output gear teeth  84  selectively mesh with at least two of idler gears  46 ,  48  and  50 . The selective meshing between at least two idler gears  46 ,  48  and  50  can best be seen in FIGS. 4 and 6. 
     The arrangement of idler gears  46 ,  48  and  50  are out-of-line relative to the axis of rotation A, and is desirable because rotation of gear system  42 , including output gear  52  (socket  22  and rotated nut  26 ) via drive gear  44 , occurs while the center socket  110  (and supported bolt  24 ), arranged in-line with the axis of rotation A, remains stationary to maintain the position of the nut  26 . Thus, a pulse gun  14  may deliver the appropriate input torque to the gear system  42  for tightening the nut  26 , while center socket assembly  74  retains the bolt  24 . As a result, the pulse gun  14  can be used to efficiently and quickly fasten bolts and nuts together. 
     With idler gears  46 ,  48  and  50  arranged out-of-line with the axis of rotation A about which drive gear  44  and output gear  52  rotate, center socket assembly  74  extends from drive gear  44  to output gear  52  and is positioned in-line with the axis of rotation A. Center socket assembly  74  includes a spring  114 , a stem holder guide  116  and a center socket  110 . Spring  114  is adjustably supported within stem holder guide  116 . Spring  114  provides a reaction force to the center socket  110  if a longitudinal force is applied along the axis of rotation A. This reaction force allows longitudinal movement of the socket during rotating conditions. Spring  114  also is maintained in an extended position when not under a load during tightening of a nut  26 . In the preferred embodiment, stem holder guide  116  has two keys  113  and  115  disposed on the outer diameter to prevent rotation when positioned. Holder guide  116  has a multifaceted bore  111  which mates to multifaceted shaft portion  120  of center socket  110 . In the preferred embodiment, bore  111  has a hex-shaped cross-section within the housing. Center socket  110  is adjustably supported against spring  114  at a first end  118 . First end  118  includes the multifaceted shaft portion  120 . In the preferred embodiment, multifaceted shaft portion  120  has a hex-shaped cross-section. Center socket  110  has a length which extends out of housing  12 , output end cap  34  and output gear  52 . A second end  122  of center socket  110  is formed as a bolt cavity  124  which is sized and shaped to support the end of a standard bolt such that when the fastener associated with a bolt is torqued, bolt cavity  124  seizes the bolt  24 , the bolt  24  remains immobile, and thereby allows nut  26  to be tightened onto bolt  24 . Multifaceted shaft portion  120  is fixably supported at at least one face by a support pin  126 . Support pin  126  fixably rests against one facet of multifaceted shaft portion  120 , and is otherwise fixably supported within housing  12  by a channel  128 . 
     Gear system  42  is coupled at the input end to drive coupling  59  which is rotatably supported within gun coupler  20 . Gun coupler  20  attaches to a standard pulse drive mechanism, for example, an Acra-Pulse® series pulse gun which can be purchased from AIMCO Corp. of Portland, Oreg. It should be appreciated that any standard pulse gun with an attachment mechanism and which provides a pulsed torque can be used. The benefit, of this interchangeability between standard commercially available pulse guns allows the functional advantages of nut driver apparatus  10  to be available with any existing equipment. 
     Gear system  42  is further coupled to a socket  22 . Output gear coupling  82  of output gear  52  supports socket  22  such that socket  22  rotates in response to the torque output provided by output gear  52 . Socket  22  is coupled, at an end opposite of output gear  52 , to a nut  26 . Accordingly, rotation of nut  26  occurs as socket  22  is rotated or torqued. 
     Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. For example, the center socket and socket of the present invention may be formed to torque many different types of fastener pairs. Fastener pairs that are securely coupled by applying a torque may be used by the present invention. 
     Still further, the gear system of the present invention may be modified to provide the torque output to the socket. For example, a planetary gear system with more than three gears can be used to deliver an output torque. Additionally, the present invention may be integrally formed with a pulse gun to provide a one-unit piece. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon studying of the drawings, specification, and the following claims: