Abstract:
An electronic torque wrench has a tubular core with elongated apertures therein which respectively removably receive user interface assembly and power assembly modules, the modules being exposed through openings in a surrounding grip sheath. A workpiece-engaging head is coupled to a beam member which may received in a tapered opening in a shim member received in an end of the tube. A sensor on the beam member is connected by wires extending to the user interface assembly, which in turn has a display device producing a bar graph display indicating the proximity of a measured torque value to a preset torque level.

Description:
RELATED APPLICATION 
   This application claims the benefit of the filing date of now abandoned U.S. provisional application No. 60/508,744, filed Oct. 3, 2003. 

   BACKGROUND 
   This application relates to wrenching tools and, specifically, to torque-measuring and recording wrenches. The application relates in particular to an improvement of the electronic torque wrench disclosed in co-pending U.S. patent application Ser. No. 10/293,006, entitled “Electronic Torque Wrench”, filed Nov. 13, 2002, the disclosure of which is incorporated herein by reference. 
   While that prior wrench works well, it is of relatively complex construction, utilizing a plurality of battery cells and an electronic module which is not easily accessible and replaceable. 
   SUMMARY 
   There is disclosed in this application an improved electronic torque wrench which avoids disadvantages of prior wrenches while affording additional structural and operating advantages. 
   In an embodiment an electronic torque wrench comprises a housing assembly including an inner generally tubular core having first and second elongated apertures formed therein, a grip sleeve telescopically received over the core and having first and second openings therein respectively communicating with the first and second apertures, a user interface assembly coupled to the core and including torque measuring apparatus and disposed in the first aperture and the first opening, a power assembly coupled to the core and disposed in the second aperture and the second opening and electrically connected to the user interface assembly; a workpiece-engaging head carried by the core and sensing apparatus carried by the housing assembly and connected to the torque measuring apparatus. 
   In an embodiment, the torque measuring apparatus includes a processor operating under stored program control, and the user interface assembly includes a data input device and display apparatus, the processor program including a routine responsive to the input device for selectively setting or changing a preset torque level, the processor program including a routine for comparing torque values measured by the torque measuring apparatus with the preset torque level and causing the display apparatus to product a bar graph display indicating the proximity of the measured torque value to the preset torque level. 
   In an embodiment, the workpiece-engaging head is part of a head assembly which includes a mounting portion receivable in the core, the wrench further including shim structure receivable in the core between the mounting portion and the core for firmly mounting the head assembly in place. 
   In an embodiment, there is also provided a method of assembling an electronic torque wrench comprising A method of assembling an electronic torque wrench comprising providing a tubular core with first and second apertures therein, mounting a user interface assembly module including a torque measuring apparatus in the first aperture, mounting a power assembly module in the second aperture, mounting a workpiece-engaging head assembly including a sensing apparatus in an end of the core, electrically connecting the sensing apparatus to the torque measuring apparatus, and fixedly securing the head assembly in the tubular core. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For the purpose of facilitating an understanding of the subject matter sought to be protected, there is illustrated in the accompanying drawings an embodiment thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated. 
       FIG. 1  is a top plan view of an electronic torque wrench; 
       FIG. 2  is a sectional view taken generally along the line  2 — 2  in  FIG. 1 ; 
       FIG. 3  is a front elevational view of the torque wrench of  FIG. 1 ; 
       FIG. 4  is a sectional view taken generally along the line  4 — 4  in  FIG. 3 ; 
       FIG. 5  is a reduced, exploded, perspective view of the torque wrench of  FIG. 1 ; 
       FIG. 5A  is a view similar to  FIG. 5  of an alternative embodiment of an electronic torque wrench; 
       FIG. 6  is a top plan view of the handle core of the torque wrench of  FIG. 1 ; 
       FIG. 7  is a sectional view taken generally along the line  7 — 7  in  FIG. 6 ; 
       FIG. 8  is a front elevational view of the handle core of  FIG. 6 ; 
       FIG. 9  is a bottom plan view of the handle core of  FIG. 6 ; 
       FIG. 10  is an enlarged side elevational view of the sensor beam of the torque wrench of  FIG. 1 ; 
       FIG. 11  is a left end elevational view of the sensor beam of  FIG. 10 ; 
       FIG. 12  is a right end elevational view of the sensor beam of  FIG. 10 ; 
       FIG. 13  is a bottom plan view of the sensor beam of  FIG. 10 , rotated 90° clockwise; 
       FIG. 14  is an enlarged top plan view of the sensor beam shim for the torque wrench of  FIG. 1 ; 
       FIG. 15  is a right side elevational view of the shim of  FIG. 14 , rotated 90° clockwise; 
       FIG. 16  is a sectional view taken along the line  16 — 16  in  FIG. 15 ; 
       FIG. 17  is a left end elevational view of the shim of  FIG. 15 ; 
       FIG. 18  is a right end elevational view of the shim of  FIG. 15 ; 
       FIG. 19  is a functional block diagrammatic view of the electronic circuitry of the torque wrench of  FIG. 1 ; and 
       FIG. 20  is a schematic diagram of a type of display which may be used in the torque wrench of  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   Referring to the drawings, there is illustrated an electronic torque wrench, generally designated by the numeral  20  ( FIG. 1 ) of the bending beam type. The torque wrench  20  has a handle assembly which includes a handle core  21 , the rear portion of which is telescopically received within a grip sleeve  30 . Referring in particular to  FIGS. 6–9 , the handle core  21  is an elongated, hollow, tubular body substantially oval in transverse cross-sectional shape, having an elongated, generally rectangular aperture  22  in the top thereof, generally longitudinally centrally thereof, and another generally rectangular aperture  23  formed in the bottom thereof adjacent to the rear end thereof, the aperture  23  extending part way up along the sides of the core. Also formed through the core  21  are two relatively large circular holes  24  adjacent to the forward end of the aperture  22 , two pairs of medium-sized circular holes  25 , with one pair immediately adjacent to the rear end of the aperture  22  and another pair adjacent to the rear end of the core  21 , and a pair of small circular holes  26  (see  FIGS. 2 and 4 ) formed in the bottom of the core  21  adjacent to the forward end thereof and aligned longitudinally centrally thereof. An oval collar  27  is adapted to fit against the front end of the core  21 , and has a generally rectangular opening  28  therethrough provided with an enlarged circular counterbore  29  (see  FIGS. 2 ,  4  and  5 ). 
   Referring in particular to  FIGS. 1–5 , the grip sleeve  30  is also substantially oval in transverse cross section and is adapted to be fitted over the rear end of the core  21 , the sleeve having an elongated, generally rectangular opening  31  formed in the top thereof and extending along most of the length thereof, and a generally rectangular bottom opening  32  substantially congruent with the top opening  31 . The rear portion of the grip sleeve  30  forms a thickened grip portion  33  provided in the outer surface thereof with a plurality of longitudinally spaced finger recesses  34  along each side thereof. The rear end of the grip sleeve  30  is closed by an end cap  35  which is provided with an oblong aperture  36  therethrough, which could be utilized for hanging the torque wrench  20  or could receive a tether cord or the like. When the grip sleeve  30  is fitted over the tubular core  21 , the elongated aperture  22  in the core  21  is substantially congruent with the forward portion of the top opening  31  in the grip sleeve  30 , while the rectangular aperture  23  in the bottom of the core  21  communicates with the rear portion of the bottom opening  32  of the grip sleeve  30 . 
   The torque wrench  20  includes an electronic module which forms a user interface assembly  40 . The assembly  40  includes an elongated upper panel  41  shaped and dimensioned to mateably fit over and close the top opening  31  of the grip sleeve  30 . Formed through the upper panel  41  adjacent to the forward end thereof is an elongated rectangular aperture  42  ( FIG. 5 ). Also formed through the upper panel  41  are a plurality of key holes  43 , a circular array of annunciator holes  44  and a pair of LED holes  45 . Depending from the inner surface of the upper panel  41  is a plurality of internally threaded cylindrical bosses  46 , the forward ones of which fit downwardly through the forward end of the aperture  22  in the core  21 , and the rear four of which respectively fit into the medium-sized holes  25  in the core  21 . The interface assembly  40  also includes a keypad  47  including four generally triangular keys  48  and two somewhat oblong keys  49  adapted to respectively fit through the key holes  43  in the upper panel  41 . 
   The keypad  47  is fixedly secured to a printed circuit board (PCB)  50 , which carries an LCD display panel  51  provided with an associated lens  52  adapted to fit in the aperture  42  in the upper panel  41 . Also mounted on the PCB  50  is an audible annunciator, which may be in the form of a buzzer  53 , positioned so as to be disposed immediately beneath the annunciator holes  44  in the upper panel  41 . Two LEDs  54  on the PCB  50  are disposed to fit respectively in the LED holes  45  in the upper panel  41 . The PCB  50  is provided with holes  56  therethrough for respectively receiving two of the bosses  46  of the upper panel  41 . The PCB  50  is also provided with two pairs of small holes  57  therethrough, respectively adjacent to the forward and rearward ends thereof, for respectively receiving suitable fasteners for threaded engagement in bosses  58  depending from the upper panel  41 , for fixedly securing the PCB  50  to the upper panel  41  (see  FIGS. 2 and 5 ). 
   The interface assembly  40  also includes a lower panel  60  which is similar in shape to the upper panel  41  and is disposed for mateably being received in and covering the bottom opening  32  of the grip sleeve  30 . The lower panel  60  carries on its inner surface adjacent to the rear end thereof a power assembly, including an open-bottom, box-like battery receptacle  61  adapted to receive a battery  62 , such as a 9-volt battery. It will be appreciated that the receptacle  61  is provided with suitable terminals (not shown) for mateably connecting with the terminals of the battery  62  and which are connected by suitable conductors (not shown) to the circuitry on the PCB  50 . The open bottom of the receptacle  61  communicates with a rectangular aperture in the rear portion of the lower panel  60 , which is covered by a cover  63 , having a tab  64  adapted to fit against the inner surface of the lower panel  60  and a hole  65  for receiving a suitable fastener for threaded engagement in an internally-threaded boss  67  on the receptacle  61 . Three pairs of tubular bosses  68  communicate with holes through the lower panel  60  and project upwardly therefrom, respectively adjacent to the forward and rearward ends thereof and approximately midway between the ends thereof, respectively fitting through the holes  24  and  25  in the tubular core  21 , for respective alignment with the bosses  46  of the upper panel  41 . Suitable fasteners (not shown) are received through the bosses  68  and threadedly engaged in the bosses  46  for securing the upper and lower panels  41  and  60  together and to the tubular core  21 , the upper and lower panels  41  and  60  cooperating to retain the grip sleeve  30  in place. 
   The torque wrench  20  also includes a head assembly including a head  70  provided with a drive lug  71  which may be square in transverse cross section. Projecting from the head  70  is a neck  72  with a hole therethrough in a known manner. The head  70  is of known construction and may be a ratchet head providing for ratcheting rotation of the drive lug  71  relative to the frame of the head and, in that case, the ratchet mechanism may be reversible and may be provided with a suitable reversing lever, all in a known manner. The head  70  is adapted to be pivotally mounted on a sensor beam assembly  75  ( FIG. 4 ). 
   Referring now also to  FIGS. 10–13 , the sensor beam assembly  75  includes an elongated sensor beam  80  provided at its forward end with a cylindrical yoke  81  having a pair of forwardly projecting arms  82  spaced apart for receiving the head neck  72  therebetween. Aligned holes  83  are respectively formed through the arms  82  for alignment with the hole and the head neck  72  to receive a suitable pivot pin for pivotally mounting the head  70  on the yoke  81 . The sensor beam  80  is provided intermediate its ends with four flats  84  arranged in a substantially square configuration, two opposed ones of the flats being further recessed to define deep flats  85 . The rear end of the sensor beam  80  has a tapered, generally frustoconical portion  86 , the forward end of which terminates at a shoulder  87 . Formed in the rear end of the tapered end  86  is an axial bore  88 , and formed radially therein are two longitudinally spaced, circular tapped holes  89  which communicate with the bore  88 . 
   Referring now also to  FIGS. 14–18 , the sensor beam assembly  75  also includes a shim  90  in a nature of a block which is substantially oval in transverse cross-sectional shape and is provided with an axial bore  91  longitudinally therethrough, one end of which is provided with a tapered, frustoconical counterbore  92 . Longitudinally spaced circular fastener holes  93  are formed in the bottom of the shim  90  and communicate with the counterbore  92 . Formed longitudinally through the shim  90 , respectively on opposite sides of the counterbore  92 , are oval tapered side passages  94 , which taper from a relatively wide front end to a relatively narrow rear end. Formed in the upper and lower surfaces of the shim  90  are two pairs of tapered grooves  95 , with each pair of grooves being laterally spaced-apart and each groove tapering from a relatively wide rear end to a relatively narrow front end. 
   In assembly, the tapered end  86  of the sensor beam  80  is mateably receivable in the tapered counterbore  92  of the shim  90 , with the forward end of the shim  90  stopping against the sensor beam shoulder  87 . The shim  90  is dimensioned to be mateably received in the forward end of the tubular core  21 , the passages  94  and grooves  95  affording a limited resilient flexibility so as to permit a snug fit of the shim  90  in the core  21 . The parts are arranged so that fasteners  98  (see  FIG. 2 ) may be received through the core openings  26  and the shim holes  93  and to be threadedly engaged in the tapped holes  89  of the sensor beam  80  for fixedly securing the shim  90  to the sensor beam  80  and securing the sensor beam assembly  75  in place in the core  21 . Before such assembly, the collar  27  is fitted over the rear end of the sensor beam  80 , being stopped against the rear end of the yoke  81  at the forward ends of the flats  84  (see  FIGS. 2 and 4 ), so that when the sensor beam assembly  75  is mounted in place, the collar  27  seats against the forward end of the core  21 . 
   Referring now to  FIG. 19 , the torque measuring apparatus may be more readily understood.  FIG. 19  illustrates a functional block diagram of an electronic circuit  100 , most of which may be disposed on the PCB  50  for controlling the operation of the torque wrench  10 . The circuit  100 , as part of the torque measuring apparatus, includes a processor  101 , which may be in the nature of a suitable microcontroller, which may have a crystal-controlled clock speed. The processor  101  operates under control of a program, which may be stored within the processor. An EEPROM  102  may be provided to store set up, preset and calibration parameters. A strain gauge bridge  103  may be provided with its output applied to the processor  101  through an analog-to digital converter (ADC)  104 . The strain gauge bridge  103  may be physically located on the deep flats  85  of the sensor beam  80  (see  FIG. 4 ) and may be connected to the remainder of the circuitry on the PCB  50  by suitable wires extending through the side passages  94  of the shim  90 . The keypad  47  forms a data input device which is coupled to the processor  101 . The keypad  47  forms a part of the user interface, which also includes the buzzer  53 , the LCD display  51  and the LEDs  54 , all of which are also coupled to the processor  101 . The battery  62  may be coupled to a suitable power supply  105 , which is also coupled to the processor  101 . The power supply  105  may include suitable voltage regulators and produce regulated DC supply voltages V+ and V++, which can be provided to the other components of the electronic circuit  100 , as needed. 
   The operation of the torque wrench  20  is similar to that described in the aforementioned copending application Ser. No. 10/293,006, and will not be described in detail here. However, the LCD display  51  may be operated to provide display indications of low battery  110 , clockwise/counterclockwise operation  111 , percent tolerance, memory, and selected units of measure  112 . The user may input a pre-programmed selectable torque value and the wrench may provide visual and audible alerts at preset, tolerance and overload coincidence. The wrench may be operated in combined torque tracking and peak capture display modes. While a six-button keypad  47  is illustrated, it will be appreciated that a four-button arrangement could also be utilized, as is explained in greater detail in the aforementioned copending application. 
   The display  51  may be operated to provide a bar graphic to give a user an approximation of the approach to or achievement of a predetermined torque setting. Referring to  FIG. 20 , such a graphic is illustrated at  115 , and may be an advancing or ascending graphic with a total window length corresponding to the predetermined torque value, with progressively greater portions of the window being “filled in” or illuminated as the predetermined torque value is approached so that the percentage of the bar illuminated is proportional to the ratio of the measured torque to the preset torque value. An LED or LCD multi-segment display  117  may provide a display of the preset torque value and/or the measured torque value. 
   The grip portion  33  of the grip sleeve  30  may be formed of a suitable flexible and resilient and frictional gripping material, such as a suitable elastomeric material, to provide a good grip. Also, the oval shape of the torque wrench core  21 , together with the design of the grip sleeve  30 , provides an improved ergonomic feel. It can be seen that the design permits easy removal or replacement of the interface assembly  40 , by simply removing a few screws. While a pivoting head  70  is illustrated, it will be appreciated that the pivot arrangement could also be one of an indexing nature or, alternatively, a fixed head could be provided. The arrangement described affords a very rugged and durable construction, while being relatively easy to assemble. 
   Referring to  FIG. 5A , there is illustrated an alternative embodiment of torque wrench, generally designated by the numeral  20 A, which is substantially similar to the torque wrench  20 , described above. Parts of the wrench  20 A which correspond to parts of the wrench  20  have the same reference numerals with the suffix “A”, and only so much of the wrench  20 A will be described herein as is necessary to explain the significant differences from the wrench  20 . 
   The wrench  20 A has a handle core  21 A which is substantially circular in transverse cross-sectional shape and has a rectangular aperture  22 A therein which is substantially longer and deeper than the corresponding aperture in the wrench  20 . The collar  27  of the wrench  20  is omitted in the wrench  20 A. The wrench  20 A has a grip sleeve  30 A, the forward end of which is circular in transverse cross section. The wrench  20 A has a user interface assembly  40 A which includes a keypad board  47 A having a pair of generally triangular keys  48 A and a pair of substantially square keys  49 A adapted to respectively fit through keyholes  43 A in an upper panel  41 A. The keypad board  47 A overlies a printed circuit board  50 A which carries an LCD display panel  51 A provided with an associated lens  52 A, the panel  51 A being raised sufficiently to allow the board  47 A to fit therebeneath. Three LED&#39;s  54 A are disposed to fit through an oblong aperture in the keypad board  47 A and may be covered with a suitable lens  55 A. 
   The interface assembly  40 A also includes a lower panel  60 A which has a pair of spaced angle brackets  61 A which cooperate to form a receptacle adapted to receive a pair of batteries  62 A, such as Lithium batteries, the forward end of which may be received in the rear end of a cradle member  66 A and may be urged against suitable contacts (not shown) by a spring member  69 A. A finger (not shown) on the upper panel  41 A engages the forward end of the cradle  66 A to limit forward movement of the cradle and the batteries. 
   A sensor beam assembly  75 A includes an elongated sensor beam  80 A with a yoke  81 A at its forward end separated by an annular shoulder  84 A from the flats of the sensor beam. The sensor beam  80 A has a cylindrical rear end  86 A adapted to be telescopically fit within the forward end of the handle core  21 A, with the shoulder  84 A seated against an O-ring  90 A which, in turn, seats against the forward end of the core  21 A. The sensor beam  80 A is held in place by suitable screws. Thus, the shim  90  of the wrench  20  is omitted. 
   The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of applicants&#39; contribution.