Abstract:
Powered drivers and methods are disclosed, the drivers including a head housing a motor driven drive transfer assembly for operating a rotatable socket engageable at a threaded connector. A reaction unit having a fitting engagement attached to rail guides is movably maintained through the head. A biasing unit is maintained at the head and is operatively associated with the rail guides of the reaction unit to bias the fitting engagement of the reaction unit toward the rotatable socket during tightening rotation of the engaged threaded connector. A probe and switch are associated with different ones of the reaction unit and the head, and are brought into operative association at selected relative locations of the reaction unit and the head during connector rotation to cause motor cessation.

Description:
FIELD OF THE INVENTION 
   This invention relates to drivers for tools, and, more particularly, relates to powered nut drivers. 
   BACKGROUND OF THE INVENTION 
   Powered drivers, both pneumatic and electrical, for manipulation of various types of tools such as sockets for threaded connectors are well known. In many applications, such as manipulation of threaded line fittings (i.e., unions or the like) found in all gas or liquid processing or delivery operations and assemblies, the tightness of the fitting is critical to assure a sound connection and to avoid leakage (which may occur if line fittings are either over or under tightened). 
   Numerous approaches to gauging the correct tightness of such connectors have been heretofore suggested and/or utilized, with varying degrees of success. Torque requirements for driving large and small fasteners varies such that the same driver often can not be employed for different fasteners. Moreover, devices and methods for gauging fitting integrity during fitting installation that are used for pneumatic tools are frequently not applicable for electrical drivers and vice versa. Such heretofore known approaches are often not highly accurate and repeatable, and/or are quite expensive computer-based applications of limited utility in the field. Further improvement of such drivers and driving methods could thus still be utilized. 
   SUMMARY OF THE INVENTION 
   This invention provides improved drivers and methods for manipulating threaded connectors that accommodate repeated precise tightening of threaded connectors based on location specific switching. The driver of this invention is capable of application over a wide variety of fastener types, independent of torque requirements and/or fastener size. The drivers and methods of this invention are appropriate for both pneumatic and electrical applications. Specified fastener tightening using the drivers and methods of this invention is highly accurate and repeatable, while yet maintaining a cost effective tool for both manufacturing and field applications. 
   Correct tightening of a connector (based on manufacturers&#39; specifications typically expressed in either torque or rotations after “finger tight”) is achieved by gauging the distance between two parts of the driver that move in a manner relative to one another correlated to the movement of the fastener, automatic cessation of driver rotation occurring upon achievement of selected relative locations of the two parts corresponding to the specified fastener tightness. 
   The driver includes a head that houses a drive transfer assembly for operating a rotatable socket that is engageable at the threaded connector. A force applying means applies motive force to the drive transfer assembly. A reaction unit movably maintained at the head is engageable at a utility related to the threaded connector (for example, a second part of a line fitting, screwing surface, bolt head, nut or the like), and is biased toward the rotatable socket during tightening rotation of the engaged threaded connector. A switching arrangement includes components associated with both the reaction unit and the head which are brought into operative association at selected relative locations of the reaction unit and the head to decouple the force applying means. 
   The force applying means may be either a pneumatic or electrical motor and related controllers (where present). The reaction unit includes a fitting engagement attached to at least one rail guide movably maintained through the head. At least one biasing unit is maintained at the head and is operatively associated with the rail guide of the reaction unit to bias the fitting engagement of the reaction unit toward the rotatable socket. The switching arrangement preferably includes a probe connected with the reaction unit and a switch operatively associated with the motor and mounted at the head at a position to be contactable by the probe. 
   The method of this invention is particularly directed to reliably repeatable rotation of threaded line fitting nuts to a selected tightness. The method includes steps of engaging the nut at a rotatable socket and rotating the nut in one direction. Another part of the line fitting is engaged at a reaction unit movably maintained adjacent to the socket. The reaction unit is biased toward the socket during rotation of the engaged nut in the one direction. The distance between the reaction unit and the socket is probed during rotation in the one direction, and, responsive to the probing, rotation is ceased when a selected relative location of the reaction unit and the socket is achieved corresponding to selected nut tightness. 
   It is therefore an object of this invention to provide improved drivers and methods for manipulating threaded connectors. 
   It is another object of this invention to provide drivers and methods for manipulating threaded connectors that accommodate repeated precise tightening of threaded connectors based on location specific switching. 
   It is still another object of this invention to provide correct tightening of a threaded connector by gauging the distance between two parts of a driver that move in a manner relative to one another correlated to the movement of the fastener during tightening. 
   It is yet another object of this invention to provide powered nut drivers and methods that provide automatic cessation of driver rotation upon achievement of selected relative locations of two movable parts of the driver corresponding to correct nut tightness. 
   It is another object of this invention to provide a powered tool driver capable of application with a wide variety of connector and fastener types, torque requirements and/or size, that is adaptable for both pneumatic and electrical applications, and that can achieve specified connector tightening in a highly accurate and repeatable manner. 
   It is yet another object of this invention to provide a powered driver for rotating a threaded connector, the driver including a head housing a drive transfer assembly operating a rotatable socket engageable at the threaded connector, means for applying motive force to the drive transfer assembly, a reaction unit engageable at a utility related to the threaded connector, the reaction unit movably maintained at the head and biased toward the rotatable socket at least during rotation of an engaged threaded connector in one direction, and switching with components associated with both the reaction unit and the head that are operatively associated to provide triggering at selected relative locations of the reaction unit and the head to decouple the means for applying motive force. 
   It is still another object of this invention to provide a powered driver for line fittings that includes a head housing a rotatable socket, a motor operatively associated with the rotatable socket, a reaction unit including a fitting engagement attached to rail guides movably maintained through the head, a biasing unit maintained at the head and operatively associated with the rail guides of the reaction unit to bias the fitting engagement of the reaction unit toward the rotatable socket, a probe connected with the reaction unit, and a switch operatively associated with the motor and mounted at the head at a position to be contactable by the probe. 
   It is another object of this invention to provide a method for reliably repeatable rotation of threaded line fitting nuts to a selected tightness that includes the steps of engaging the nut at a rotatable socket and rotating the nut in one direction, engaging another part of the line fitting at a reaction unit movably maintained adjacent to the socket and biasing the reaction unit toward the socket during rotation of the engaged nut in the one direction, gauging relative locations of the reaction unit and the socket during rotation in the one direction, and, responsive to the gauging, causing cessation of rotation when a selected relative location of the reaction unit and the socket is achieved corresponding to selected nut tightness. 
   With these and other objects in view, which will become apparent to one skilled in the art as the description proceeds, this invention resides in the novel construction, combination, and arrangement of parts and method substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that changes in the precise embodiment of the herein disclosed invention are meant to be included as come within the scope of the claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings illustrate a complete embodiment of the invention according to the best mode so far devised for the practical application of the principles thereof, and in which: 
       FIG. 1  is a perspective view showing the tool driver of this invention; 
       FIG. 2  is a reverse perspective view of the driver of  FIG. 1 ; 
       FIG. 3  is a partial exploded view of the housing and components of the driver of this invention; 
       FIG. 4  a detailed exploded view of housed drive train elements not shown in  FIG. 3 ; 
       FIG. 5  is a partial exploded view of the driver head of the driver of this invention; 
       FIG. 6  is a second partial exploded view of the head of the driver of this invention; 
       FIG. 7  an elevation view of the head of the driver of this invention with the top cover removed; 
       FIG. 8  is a sectional view taken along section lines  8 - 8  of  FIG. 3 ; 
       FIG. 9  is a sectional view taken along section lines  9 - 9  of  FIG. 7 ; 
       FIG. 10  is a sectional view taken along section lines  10 - 10  of  FIG. 7  but with the top cover and reaction unit in place; 
       FIG. 11  is a partially exploded perspective view showing additional features which may accompany the driver of this invention; 
       FIG. 12  is a perspective view illustrating still other additional features which may accompany the driver of this invention; and 
       FIGS. 13 through 15  are schematic diagrams showing the electronics of the driver of this invention. 
   

   DESCRIPTION OF THE INVENTION 
   Powered driver  21  of this invention, for rotating tools such as sockets or the like to manipulate threaded connectors, is illustrated in  FIGS. 1 through 3 . Driver  21  includes driver head  23 , motor module  25  (any means of applying motive force could be used including electrical, pneumatic or fluid drive motors), electronics module  26 , reaction unit  27 , housing  29 , and battery pack  30 . Torque amplification drive train modules  32  and  33  provide a drive train capable of staged increase of torque from a motor  25  rating of about 0.18 ft.lbs. to over 35 ft.lbs., thereby accommodating connector manipulation in a wide variety of size and torque application categories (torque amplification is adaptable to requirements). Housing  29  is hollow at both barrel portion  35  and handle portion  37  thus providing the required space and protection for driver electrical components as hereinafter discussed. Battery pack  30  is of standard configuration and includes a standard conductive slide connector  39  (with mating unit  41  at handle portion  35 ) providing both connectivity and security of batteries in pack  30 . 
   As shown in  FIGS. 3 and 4 , torque amplification modules  32  and  33  include discrete gear sets in separate housings to accommodate different torque output requirements in different tool configurations. The final output stage  33  includes primary drive output shaft and bevel gear  45  receivable through opening  47  at head  23  (see  FIG. 5 ). 
   Operational switches, lights and ports are readily accessible, including main on/off switch  51 , main operational running switch/trigger  53 , forward and reverse jog rocker switch  55  (for advancing or retreating rotation by one to five degree increments), and lights switch  57  (operating white light  59  and red, night light  61 ). USB port  63  provides communication and data download capabilities (from onboard controller memory) as discussed hereinafter. Control lights  65 ,  67 ,  69  and  71  are provided to indicate tool on/off status (yellow— 65 ) and socket status ( 67 —green indicating socket  73  centering at jaw opening  75  and safety switch  77  tripped by placement of a line and fitting  79  (see  FIG. 2 )). Light  69  blinks (red) at each full rotation of socket  73 , and thus a fitting engaged thereat, and light  71  indicates (blue) when the correct connector tightness (nut to fitting body gap, for example) has been achieved. 
   Housing  29  is preferably a split housing (as shown) held by common fastener techniques, with the housing, when assembled, capturing head  23  at mounting bracket  80 . Modules  25 ,  26 ,  32  and  33  are affixed to one another and to head  23  utilizing standard screw type fasteners  82 . 
   Turning now to  FIGS. 5 through 10 , head  23  and reaction unit  27  will be described in greater detail. Head  23  includes main body  83  and top cover  85  held together using screws  87 . Gapped jaw  75  is utilized in this embodiment of the driver to accommodate use of a split socket tool  73  (a hex socket, for example) used to manipulate line fittings ( 79 , as shown in  FIG. 2 ). Drive translate assembly  89  includes stacked gears  91  and  93  on shaft  95  and bearing set  97  pressed into main body mounting  99 , bevel gear  93  engaged by primary drive output gear  45  of final output stage  33  of torque amplification modules  32  and  33 . The opposite end  101  of shaft  95  is rotatably fitted into mount  103  in cover  85 . 
   Drive transfer gear assembly  107 , including main drive gear  109  and idler gears  111  and  113 , complete the drive train. Main drive gear  109  engages gear  91  of translate assembly  89  and is mounted on shaft  115  of main body  83 . Idler gears  111 / 113  are used in split socket applications, providing constant drive application to socket  73 , and are mounted on bearing shoulders  117  in housing detents  119  and cover openings  121 . Socket  73  is mounted on bearing shoulder  123  in housing detent  125  and cover opening  127 . Main drive gear  109  and socket  73  preferably are the same size and have the same gear tooth count, so that rotation thereof is one to one. Cam surface  131  is provided at gear  109  and follower  133 , the roller of roller switch  135 , is mounted at main body  83  adjacent thereto using screws  137 . This arrangement provides indication of socket  73  rotation at light  69  as well as socket location (in degrees) and rotation counting in onboard controller software or firmware. 
   Reaction unit  27  includes fitting engagement  141  (gapped for receipt of line fittings as shown in this embodiment) for engaging a utility related to the connector being manipulated (for example, a line fitting body, the second part of a line fitting assembly not including the nut). Engagement  141  in this embodiment, for example, includes a sized slot  143  having surfaces configured to receive and securely hold a hexagonal fitting body. Rail guides  145  and  147  (a single guide could be utilized in some embodiments of the driver of this invention) are received at reduced diameter threaded ends  149  through openings  151  of engagement  141  and are held thereat by cap nuts  153 . 
   Guide  145  includes second reduced diameter end  155  engageable (pressed into) opening  157  of piston  159 . Guide  145  also includes intermediate annular slot  161  for capture and retention of reaction unit  27  by clip  163  at cover  85  (during fitting loading, reaction unit  27  must be held in an opened, disengaged position, since, as will be appreciated, the entire unit  27  is spring biased). Guides  145  and  147  are receivable through openings  121  in cover  85 , through openings  164  of idler gears  111  and  113 , and the openings into body  83  through threaded shoulders  165 . 
   Clip  163  is mounted at the end of spring biased latch body  166  held in latch mount  167  attached to cover  85 . Spring  169  is held in mount  167  between body  166  and mount  167  and biases body  166  so that clip  163  is urged toward and across one opening  121  of cover  85  and into engagement with rail guide  145 . Release grip  171  protrudes from body  166  allowing user access for movement of latch body  166 . Sliding movement of reaction unit  27  on guides  145  and  147  (against unit bias as discussed hereinafter) away from head  23  eventually results in movement of clip  163  into engagement at annular slot  161  thus allowing cocked retention of reaction unit  27  at this position. Once a fitting is correctly positioned at the driver, retraction of latch body  166  using release grip  171  by a user frees clip  163  from slot  161  allowing movement of unit  27  toward head  23  and into correspondence with a connector utility at engagement  141 . 
   Probe component  175  of switching assembly  177  is threadably received through opening  179  of engagement  141 , probe reach being adjustable by extent of threaded engagement. Probe end  181  is receivable through openings  183  and  185  in cover  85  and body  83 , respectively. Switch component  187  of assembly  177  (a roller switch, for example) is attached by screws  189  to a mounting block  191  (as shown in  FIG. 11 ) on body  83  to position the roller of roller switch  187  over opening  185  and thus in the path of probe end  181 . Switch component  187  is operatively linked (through controls as shown hereinafter) with the main motor of the driver to decouple motive force when tripped by probe end  181 . 
   Engagement  141  of reaction unit  27  is biased toward driver head  23  (and particularly toward socket  73 ) by springs  195  in closed ended retainers  197  and  199  threadably engaged at shoulders  165 . Springs  195  are maintained between shoulders  165  and piston  159  at retainer  197  and slide  201  at retainer  199  thus biasing the piston and the slide (and so guides  145  and  147  and the rest of reaction unit  27 ) toward the closed ends of the retainers  197  and  199 . Slide  201  is retained at the end of guide  147  by manually releasable spring clip  203  received through slide slot  205 , threaded opening  207  in slide  201  and annular slot  209  at guide  147 . When spring clip  203  is retracted from slot  209  thus releasing guide  147 , reaction unit  27  may be fully withdrawn from head  23 . 
   As may be appreciated, as a fitting nut is tightened on a fitting body using the driver of this invention, engagement  141  of reaction unit  27  in contact with the fitting body is biased toward socket  73  at the same rate as the nut moves toward the fitting body. At the same time, probe end  181  is proceeding at this rate toward switch component  187 . By virtue of probe length and/or geometry selection (either factory selected for particular operations, threadably adjustable, or by selection and installation of one of a variety of probe components having different selected lengths for different fitting specifications), switch contact occurs when correct connector or fitting (nut to body gap) tightness is achieved thereby causing cessation of socket rotation. Such operations are highly predictable and thus repeatable. Since most motor and drive trains have overrun (i.e., a few degrees of continued rotation due to system momentum), the driver is programmed with an automatic reverse rotation at the end of the tightening cycle corresponding to estimated system overrun to relieve system tension without changing nut torque. Use of the jogging function can provide further tightening or loosening as desired. After disengagement from a tightened fitting, split socket  73  is run to the gap centered position relative to jaw opening  75  (for example, in a fully automated mode, by a subsequent press of trigger switch  53  after release thereby running socket  73  to the centered position—indicated by light  67 —and resetting the driver for a new connector driving cycle). 
   Reaction unit  27  may be manually reset for a new cycle (“cocked” as described above) or may be reset by pneumatic means as shown herein. Pneumatic fitting  211  is threaded at opening  213  of retainer  197  and connected by line  215  with valve  217  and pressurized gas cylinder  219 . After a fitting is tightened, triggering valve  217  causes a burst of gas to enter retainer  197  through opening  213  forcing piston  159  against spring bias to move guide  149  (and thus unit  27 , releasing and resetting switch component  187 ) until slot  161  captures spring biased retaining clip  163 . 
   Turning to  FIGS. 11 and 12 , several additional driver features may be provided to enhance safety and utility. Safety switch assembly  225  includes switch  77  pivotably biased to a position closing gapped jaw  75 . When forced open by a line or other fitting  79 , switch  77  geometry causes engagement at roller switch  227  attached to head  23  thereby electrically enabling driver operation. A second pneumatic fitting  229  is positioned for access to the interior of retainer  197 . Line  231  connected with fitting  229  is received at port  233  of a test fixture  235  to thereby receive continuously aspirated samples from the fitting\connector union area through retainer  197  and bore hole  236  through guide  145  (see  FIG. 5 ). Leak detection at a fitting may thus be accommodated. 
   Test fixture  235  may be belt mounted, as shown, and may include a USB input  239  (for communication through the USB port at the driver or with a base computer). BLUE TOOTH and/or radio communication may be provided for data download from the driver or upload from a base station. Cellular technology may also be accommodated for the user, with a speaker  241  and microphone  243  positioned at housing  29  or any of the driver modules. Real time video may be provided at video unit  245  (and downloaded or stored with appropriate in-situ memory), allowing remote review of operations and/or a record of completed tasks. 
     FIGS. 13 through 15  illustrate the electronic implementation of driver  21  of this invention, the boards described hereinafter housed in module  26 . Main control board  247  ( FIG. 13 ) is connected with switching board  249  ( FIG. 14 ) at port connectors  251 . Board  249  is connected with the two one-half h-bridge circuits  253  and  255  at connectors  257  and  259  ( FIG. 15 ), the h-bridge circuits driving motor  261  (housed at module  25 ) in a conventional arrangement. Main board  247  includes a smart highside current power switch arrangement  263  (for example, a PROFET BTS660P by INFINEON TECHNOLOGIES) and a Flash USB ready microcontroller  265  (for example, a PIC18F2455/2550/4455/4550 series 28/40/44 pin microprocessor by MICROCHIP TECHNOLOGY, INC.) connected with clock oscillator  266 . USB signals are accommodated at the connector to USB port  63 . 
   Programming/reset circuits  267  are provided for programming and trouble shooting with programming switch  269  (modes may include everything from fully manual to fully automated), and voltage regulation is provided by regulator circuit  270 . Momentary rocker switch  55  with center off provides for input to controller  265  of jog functions, and trigger switch  53  inputs running commands. Safety gate switch  227  inputs run ready signals, and rotation counter switch  135  inputs socket rotation count/location data. 
   Connectors  281  and  283  at switching board  249  are connected with lights  61  and  59 , respectively, for operations responsive to switch  57  actuation. Switch  285  is a mode selection switch (manual or auto). On/off switch  51  signals are input through, and motor control signals are output through, board  249 . H-bridge circuits  253  and  255  include integrated motor drivers  287  and  289 , respectively (for example, VNH2SP30-E drivers from ST). 
   As may be appreciated, this invention provides a highly adaptable driver for precise manipulation of threaded connectors that employs location specific switching to accomplish reliable connector tightening. The gap probing techniques discussed herein (their particular location and the triggering embodiments shown in the FIGURES) are illustrative, it being understood that a variety of probing means and relative positions of switches and triggering related to location specific on/off switching could be utilized. By way of example, switch location could be anywhere along a mechanical probe or at either end, and probing could be conducted mechanically (as shown), electronically, magnetically or optically. Switches, likewise, could be mechanical (as shown) or sensory (optical, magnetic, electronic, etc.), or embodied in software. One particularly useful alternative replaces limit switch  187 / 177  with a linear resistor to regulate motor speed (to regulate nut to body gap closure speed at different stages of the traversed distance) as well as motor shut off.