HYBRID ELECTROMECHANICAL TORQUE WRENCH

Abstract

A torque wrench having post-torque rotation setting and measurement function, optionally including auto transition from torque to angle rotation, which may operation with and without batteries, including low profile design, improved visual, audio and haptic feedback, a recesses pawl seat for improved accuracy and longevity and improved handle rotation for torque setting and spring unwinding by virtue of improved torque setting nut design.

Claims

1. An apparatus comprising: a main tube defining an elongated interior compartment; a wrench head including a workpiece engaging portion and a bar extending therefrom, said wrench head being pivotally secured to a first end of said main tube at a pivot joint, said bar extending into said interior compartment and said workpiece engaging portion extending outwardly from said main tube; a hand grip located on a second end of said main tube; a set spring disposed within said interior compartment of said main tube; a pawl disposed between a rear face of said bar and said set spring; a torque setting screw threadably received within said interior compartment of said main tube, such that rotation of said torque setting screw in a first direction drives compresses said set spring and rotation in a second direction allows expansion of said set spring; a set ring positioned adjacent said hand grip, said set ring being operatively connected to said torque setting screw and rotatable relative to said main tube; an accelerometer operatively connected to a microcontroller; an input interface operationally mounted on said torque main tube; an electronic display operationally mounted on said torque main tube; an electronic audio output device operationally mounted on said torque main tube; said microcontroller configured to receive acceleration data from said accelerometer and angle of rotation input data from said input interface, and to output result data to said electronic display, sound instructions to said electronic audio output device, and/or vibration signal to vibration generating motor.

2. A mechanical torque wrench for engaging a workpiece, comprising: a main tube defining an elongated interior compartment; a wrench head including a workpiece engaging portion and a bar extending therefrom, said wrench head being pivotally secured to a first end of said main tube at a pivot joint, said bar extending into said interior compartment and said workpiece engaging portion extending outwardly from said main tube; a hand grip located on a second end of said main tube; a set spring disposed within said interior compartment of said main tube; a pawl disposed between a rear face of said bar and said set spring; a torque setting screw threadably received within said interior compartment of said main tube, such that rotation of said torque setting screw in a first direction compresses said set spring and rotation in a second direction allows expansion of said set spring; a set ring positioned adjacent said hand grip, said set ring being operatively connected to said torque setting screw and rotatable relative to said main tube; a resistive element operatively coupled to said torque setting screw and producing an output signal, said output signal being dependent on a position of said torque setting screw relative to said resistive element; a microcontroller for converting said output signal into an equivalent torque value, said equivalent torque value indicating a preset torque to be applied by said mechanical torque wrench to the workpiece; a user interface including a display for displaying said equivalent preset torque value; said mechanical torque wrench further having physical torque scale markings thereon for presetting of desired torque in the absence of batteries.

3. A mechanical torque wrench for engaging a workpiece, comprising: a main tube defining an elongated interior compartment; a wrench head including a workpiece engaging portion and a bar extending therefrom, said wrench head being pivotally secured to a first end of said main tube at a pivot joint, said bar extending into said interior compartment and said workpiece engaging portion extending outwardly from said main tube; a hand grip located on a second end of said wrench body; a set spring disposed within said interior compartment of said main tube; a tiltable pawl disposed between a rear face of said bar and said set spring; a torque setting screw threadably received within said interior compartment of said main tube, a PCB spacer bar disposed in said main tube between said torque setting screw and said set spring, such that rotation of said torque setting screw in a first direction translationally drives said PCB spacer bar to compress said set spring and rotation in a second direction withdraws said spacer bar and allows expansion of said set spring; a set ring positioned adjacent said hand grip, said set ring being operatively connected to said torque setting screw and rotatable relative to said wrench body; a resistive element operatively coupled to said PCB spacer bar and producing an output signal, said output signal being dependent on a position of said spacer bar relative to said resistive element; a microcontroller for converting said output signal into an equivalent torque value, said equivalent torque value indicating a preset torque to be applied by said mechanical torque wrench to the workpiece; a user interface including a display for displaying said equivalent torque value; said PCB spacer bar having a cross section dimensioned so that said resistive element is recessed at least partially into the main tube.

4. An apparatus comprising: a main tube defining an elongated interior compartment; a wrench head including a workpiece engaging portion and a bar extending therefrom, said wrench head being pivotally secured to a first end of said main tube at a pivot joint, said bar extending into said interior compartment and said workpiece engaging portion extending outwardly from said main tube; a hand grip located on a second end of said main tube; a set spring disposed within said interior compartment of said main tube; a tiltable pawl disposed between a rear face of said bar and said set spring; a torque setting screw threadably received within said interior compartment of said main tube, such that rotation of said torque setting screw in a first direction drives compresses said set spring and rotation in a second direction allows expansion of said set spring; a set ring positioned adjacent said hand grip, said set ring being operatively connected to said torque setting screw and rotatable relative to said wrench body; an accelerometer or gyro operatively coupled to a microcontroller; an input interface mounted on said torque main tube; one or more output devices mounted on said torque main tube, said one or more output devices comprising one or more of a visual display output device, an electronic audio output device and a haptic output device; said microcontroller configured to receive inertial/acceleration data from said accelerometer or gyro, and to output visual, sound and/or haptic feedback instructions to said one or more output devices.

5. A mechanical torque wrench for engaging a workpiece, comprising: a main tube defining an elongated interior compartment; a wrench head including a workpiece engaging portion and a bar extending therefrom, said wrench head being pivotally secured to a first end of said main tube at a pivot joint, said bar extending into said interior compartment and said workpiece engaging portion extending outwardly from said main tube; a hand grip located on a second end of said main tube; a set spring disposed within said interior compartment of said main tube; a tiltable pawl disposed in recessed pawl seat between a rear face of said bar and said set spring, said pawl seat having a cross-section that is smaller than said rear face of said bar so that when said torque wrench reaches a preset torque, said pawl seat does not contact an inside surface of said main tube; a torque setting screw threadably received within said interior compartment of said main tube, such that rotation of said torque setting screw in a first direction compresses said set spring and rotation in a second direction allows expansion of said set spring; a set ring positioned adjacent said hand grip, said set ring being operatively connected to said torque setting screw and rotatable relative to said wrench body.

6. A mechanical torque wrench for engaging a workpiece, comprising: a main tube defining an elongated interior compartment; a wrench head including a workpiece engaging portion and a bar extending therefrom, said wrench head being pivotally secured to a first end of said wrench body at a pivot joint, said bar extending into said interior compartment and said workpiece engaging portion extending outwardly from said main tube; a hand grip located on a second end of said main tube; a set spring disposed within said interior compartment of said main tube; a pawl disposed in recessed pawl seat between a rear face of said bar and said set spring, a torque setting screw threadably received within a torque setting nut located at an end face of said wrench body, such that rotation of said torque setting screw in a first direction compresses said set spring and rotation in a second direction allows expansion of said set spring; said torque setting nut having a shoulder portion that extends longitudinally beyond said end face of said wrench body and radially away from a longitudinal axis of said wrench body to contact an inside surface of said hand grip; a set ring positioned adjacent said hand grip, said set ring being operatively connected to said torque setting screw and rotatable relative to said wrench body.

7. A split beam torque wrench comprising: a wrench body; a wrench head including a workpiece engaging portion, said wrench head being pivotally secured to a first end of said wrench body at a pivot joint; a handle located on a second end of said wrench body; said wrench body having a main beam extending from said first end to said handle and an anchor beam extending from said first end and terminating at an end separated from said handle; a catch pivotally connected to said main beam and releasably connected to said anchor beam; a torque setting screw threadably received in said handle such that rotation of said torque setting screw in a first direction biases said main beam away from said anchor beam and rotation in a second direction biases said main beam toward said anchor beam; an accelerometer or gyro operatively connected to a microcontroller; an input interface mounted on said handle; an electronic display operatively connected to said microcontroller; said microcontroller configured to received acceleration data from said accelerometer or gyro and angle of rotation input data from said input interface, and to output result data to said electronic display and sound instructions to said electronic audio output device.

8. A mechanical torque wrench for engaging a workpiece, comprising: a main tube defining an elongated interior compartment; a wrench head including a workpiece engaging portion and a bar extending therefrom, said wrench head being pivotally secured to a first end of said main tube at a pivot joint, said bar extending into said interior compartment and said workpiece engaging portion extending outwardly from said main tube; a hand grip located on a second end of said main tube; a set spring disposed within said interior compartment of said main tube; a tiltable pawl disposed between a rear face of said bar and said set spring; a torque setting screw threadably received within said interior compartment of said main tube, such that rotation of said torque setting screw in a first direction compresses said set spring and rotation in a second direction allows expansion of said set spring; a set ring positioned adjacent said hand grip, said set ring being operatively connected to said torque setting screw and rotatable relative to said main tube; a resistive element operatively coupled to said torque setting screw and producing an output signal, said output signal being dependent on a position of said torque setting screw relative to said resistive element; a microcontroller for converting said output signal into an equivalent torque value, said equivalent torque value indicating a preset torque to be applied by said mechanical torque wrench to the workpiece; a user interface including a display for displaying said equivalent torque value; wherein said display is provided with one or more of the following: vivid colors, real-time dynamically scaled font sizes, and real-time changing background colors to indicate critical steps during use.

9. A mechanical torque wrench for engaging a workpiece, comprising: a main tube defining an elongated interior compartment; a wrench head including a workpiece engaging portion and a bar extending therefrom, said wrench head being pivotally secured to a first end of said main tube at a pivot joint, said bar extending into said interior compartment and said workpiece engaging portion extending outwardly from said main tube; a hand grip located on a second end of said main tube; a set spring disposed within said interior compartment of said wrench body; a tiltable pawl disposed between a rear face of said bar and said set spring; a torque setting screw threadably received within said interior compartment of said main tube, such that rotation of said torque setting screw in a first direction compresses said set spring and rotation in a second direction allows expansion of said set spring; a set ring positioned adjacent said hand grip, said set ring being operatively connected to said torque setting screw and rotatable relative to said main tube; a resistive element operatively coupled to said torque setting screw and producing an output signal, said output signal being dependent on a position of said torque setting screw relative to said resistive element; a microcontroller for converting said output signal into an equivalent torque value, said equivalent torque value indicating a preset torque to be applied by said mechanical torque wrench to the workpiece; a user interface including an electronic display for displaying said equivalent torque value; an accelerometer or gyro operatively connected to a microcontroller; an input interface mounted on said torque main tube; an electronic audio output device coupled to said torque main tube; said microcontroller configured to received acceleration data from said accelerometer and angle of rotation input data from said input interface, and to output result data to said electronic display; said microcontroller further configured to automatically transition from torque mode to angle of rotation mode during use without interruption or additional user input.

10. An apparatus according to claim 1, wherein said torque wrench body has analog torque scale indicators printed, stamped, embossed, painted, engraved or otherwise marked thereon.

11. An apparatus according to claim 1, comprising a recessed resistive element for converting rotational or translational movement of PCB spacer to torque setting and application.

12. An apparatus according to claim 1, comprising enhanced visual audio, visual and/or haptic feedback.

13. An apparatus according to claim 1, comprising a recessed pawl seat.

14. A split beam torque wrench according to claim 7 further comprising a rotary resistive element coupled to said microcontroller for converting.

15. An apparatus according to claim 1, comprising a torque setting nut with a shoulder portion that is dimensioned to match an inside diameter of the hand grip.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The foregoing summary, as well as the following detailed description of the preferred invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings various embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

[0034] FIG. 1A is a cutaway perspective view of an electromechanical Click-to-Angle according to an embodiment of the invention.

[0035] FIG. 1B is a cutaway view of the electromechanical Click-to-Angle of FIG. 1A.

[0036] FIG. 1C is an exploded view of an electromechanical Click-to-Angle according to an embodiment of the invention.

[0037] FIG. 2 is a block diagram representation of an electronic controller for an electromechanical Click-to-Angle according to an embodiment of the invention.

[0038] FIG. 3 is a representation of a dual Digital Display 8 and mechanical scale 11 according to an embodiment of the invention.

[0039] FIG. 4 is a close-up cross sectional view of a low profile embodiment of the invention including PCB spacer and PCBA. This close up cross-sectional view shows PCB Spacer 20, main tube 5, high viz dynamic color TFT display 8, operating keys 10, and tracer/nub of displacement sensor 25. The tracer 25 rests in an annular groove of spacer 20 and translates as the torque setting screw 22 is rotated to set target torque.

[0040] FIG. 5 is a schematic drawing showing a configuration of electronic controller hardware according to an embodiment of the invention including audio output device (e.g., buzzer) 7, display 8, inertial sensor (e.g., gyro, accelerometer) 26, LED indicator light 27 and haptic feedback device (e.g., vibration motor) 28.

[0041] FIG. 6 is a flow chart for a click detection and alert algorithm according to an embodiment of the invention.

[0042] FIG. 7 shows acceleration in x, y and z axes just before, during and after the preset torque has been reached according to an embodiment of the invention. This data is analyzed to detect the exact moment “click” occurs.

[0043] FIG. 8 shows an example of acceleration data processing that enables click detection (reaching pre-set torque) according to an embodiment of the invention. One preferred method of detection is to use summation of acceleration in x, y and z axes just before, during and after the preset torque has been reached, followed by determining when the slope over a moving window crosses a preset threshold value The time at which the threshold is reached is considered as a “click” and alert signals are output to audio, visual and haptic signal generators.

[0044] FIG. 9A is a perspective view of a typical split beam torque wrench.

[0045] FIG. 9B is a closeup view of a split beam torque wrench which includes electronic torque and angle setting and detection according to an embodiment of the invention.

[0046] FIG. 10 is a partial cutaway view of a prior art click wrench showing how the pawl seat hits the main tube at the click point.

[0047] FIG. 11 is a partial cross sectional view of an embodiment of the invention in which the pawl seat is recessed behind the hinge in order to protect alignment of the pawl seat with the cam.

[0048] FIG. 12 is a partial cross-sectional view of a prior art mechanical torque wrench in which the main tube and the rotary scale tube share a length of frictional engagement.

[0049] FIG. 13 shows an improved nut according to an embodiment of the invention having a shoulder portion of the torque setting nut with shoulder contacting the main tube.

[0050] FIG. 14 is a partial cross sectional view of a torque wrench having a torque setting nut with shoulder and showing the two points of contact between the main tube and scale tube according to an embodiment of the invention.

[0051] Features in the attached drawings are numbered with the following reference numerals:

TABLE-US-00001 1-Flex Head 4-Rubber Seal 2-Hinge 5-Main Tube 3-Hinge Pin 6-Plastic Housing Assembly 7-Buzzer 28-Vibration motor 8-Color TFT Display 101-Split Beam Flex Head 9-Battery Compartment 102- Split Beam Torque Tube 10-Input Keys 103- Split Beam Torque Indicator 11-Mechanical Linear Scale 104- Split Beam Torque Scale 12-Rotary Scale 105- Split Beam Handle 13-Lock Collar 106- Split Beam Rotary Torque Setting Knob 14-Handle 14-Knurled Handle press fit over Scale Tube 107- Split Beam Knob Enclosure 15-Ratchet Gear Pawl Reversing Lever 108- Split Beam Electronic Controller Housing 16-Tilting Pawl 17-Pawl Seat 109- Split Beam TGT Display with Dynamic Color 18-Cam 19-Torque Spring 110- Split Beam Unit Key 20-PCB Spacer 111- Split Beam Main Beam 21-Electronic Controller PCB 112- Split Beam Mode Key 22-Torque Setting Screw 113- Split Beam Scroll Up Key 23-Torque Setting Nut with shoulder 114- Split Beam Scroll Down Key 24-Scale Tube 115- Split Beam Power Button 25-Displacement Sensor Tracer 116-Split Beam Anchor Beam 26-Acceleration Sensor 117-Split Beam Catch 27-LED 118-Potentiometer

DETAILED DESCRIPTION OF THE INVENTION

[0052] The invention described herein presents for the first time a single tool that provides both a mechanical torque wrench or “clicker” function and the ability to set a desired post-torque angle of rotation and notify the user when the set post-torque angle of rotation has been achieved. Furthermore, this invention enhances the haptic (click) feedback by detecting the click electronically and generating additional visual and audio signals. This invention consolidates two tools into one, improving efficiency and productivity. The inventors have coined the term “Click-to-Angle” for this hybrid electromechanical torque wrench with post-torque set-angle rotation.

[0053] According to various embodiments of the Click-to-Angle invention, an electronic controller is integrated into a typical mechanical torque wrench or “clicker” to result in a hybrid device that can also be used to set a desired post-torque angle of rotation and notify the user when the set post-torque angle of rotation has been achieved. In addition to standard mechanical torque wrench functions, the Click-to-Angle tool of the invention may include: [0054] a novel angle measurement function; [0055] high-visibility digital display of set torque and angle (in monochrome and/or multiple color); [0056] visual feedback showing real-time angle during rotation; [0057] haptic feedback to signal when the specified angle is reached; [0058] audible sounds to signal when the specified angle is reached; [0059] storage for multiple angle measurements; [0060] communication to external devices, and [0061] enhance the traditional haptic feedback due to “clicking” by additionally generating visual and audio feedback when click occurs (this feature improves usage of the device in especially noisy environments); as well as other supporting functions.

[0062] FIG. 1A shows a Perspective view of one preferred embodiment of the new Hybrid Electromechanical Torque Wrench. Flex Head is a sub assembly of high strength steel subassembly consisting of drive gear, pawl, Reversing Lever, etc. Similarly Plastic Housing Assembly consists of two or more plastic parts that accommodates electronic Control PCB, Batteries, haptic actuator in the form of an unbalanced mass motor, and fasteners. FIG. 1B shows the cross-sectional view showing how all the parts are arranged inside the Main Tube and Plastic Housing. FIG. 1C shows a closeup view of printed/stamped/etc. analog linear scale and rotary scale.

[0063] FIG. 2 is a block diagram representation of the electronic controller of an Click-to-Angle according to an embodiment of the invention. As the user turns the torque setting screw to set desired torque, the position sensor mounted on the translating PCB spacer generates an electrical signal which is then converted to a digital signal by the microcontroller. The microcontroller collects this information and displays it on the LCD via I2C/SPI communication. Alternatively, the user can select the desired torque unit (N.m, ft-lb, in-lb, kg.cm, etc) using the keyboard. The battery level is also monitored so the user is notified when it is low. Once desired torque is set, the operator can set the target angle on the LCD panel through key input. The user can now apply torque by rotating the Click-to-Angle Torque Wrench. When the desired torque is reached, in addition to the traditional mechanical “click” sound and a sudden release of resisting torque, this Click-to-Angle will enhance the occurrence of “click” by notifying the user by LEDs, audible devices, and/or haptic actuator. The user may then continue rotation of the Click-to-Angle toward the desired post-torque angle of rotation. The angle sensor, for example a MEMS gyro IC chip, will read the gyro rate and acceleration rate in x, y, and z directions, as well as the temperature data (accurate angle calculation requires the temperature at which the gyro is operating), which is then displayed on the LCD. When the preset angle is reached, the operator is notified by LEDs, audible devices, and/or haptic actuator. Additionally, the electronic controller can communicate with external devices via USB port, which facilitates data uploads and downloads.

[0064] Additionally the angle sensor/on-board MEMS gyro IC may record and save the accelerometer output in X, Y, and Z directions. This can be used to detect if the unit has been dropped or not. From the service point of view, this information is very valuable.

[0065] According to preferred embodiments of the invention, a color TFT LCD may be used as a display device to provides not only high contrast display, but also enable functions such as (i) significantly improved sunlight readability, (ii) color coded easy to grasp information, (iii) user specific customizable icon display, (iv) programmable LED icons in variety of colors eliminating the need for specialized LED hardware, (v) off-site product updates with new icons, (vi) display of progression bars instead of additional LEDs on the PCB, (vi) ability to display any characters/icons, etc.

[0066] According to another embodiment of the invention, the Angle-Clicker may be functional with or without batteries by providing both a digital display and an analog scale printed on the body of the instrument as shown in FIGS. 1C and 3. With this invention, the user may use the easy-to-read digital display under normal circumstances, but if the batteries run out, the Click-to-Angle is still fully functional through use of the analog scale. Unlike other mechanical torque wrenches with digital display that are limited by battery life, the present invention is functional with or without batteries, essentially providing continuous usage.

[0067] According to another embodiment of the invention, a low-profile design is provided that increases the availability of the tool for use in tight spaces. According to this embodiment, and referring to FIG. 4, the outer tube is cut/segmented, and a narrow-diameter PCB spacer 20 (for example, a tube, rod or bar) is placed between the torque spring 19 and torque setting screw 22 to house the displacement sensor/potentiometer 118. In this fashion, the potentiometer 118, display bezel 8, and PCB 21, can be positioned closer to the central axis of the tool so that the projection of the display bezel from the top of the tube can be significantly reduced thus making available for use in tight spaces.

[0068] In the preferred configuration shown in the previous disclosure, the torque wrench operates as follows: [0069] 1. Power on the electronic controller. [0070] 2. Select Angle mode using mode button [0071] 3. Using up down buttons set the target Angle in degrees [0072] 4. Change to Torque mode using mode button [0073] 5. Select unit of display (ft-lb, in-lb, N-m, Kg-cm) [0074] 6. Rotate the handle to set target torque value and digitally display the target toque value and units [0075] 7. Start applying torque on the fastener until the unit clicks that is sensed tactically (a sudden drop of resistive force) and also hearing the metal to metal click sound. [0076] 8. Keeping the unit in place, change to angle mode and target angle will be displayed [0077] 9. Rotate the wrench until the progressive LED lights go from Green to RED, real-time angle display reaches the target angle, the buzzer goes on, and the tactile sensing of vibration produced by a motor.

[0078] With this, the application of Click-to-Angle of the fastener is completed.

[0079] While the steps above describe desired torque and angle being set at the beginning, the desired angle can be set after the preset torque has been reached. Furthermore, in addition to dual (torque + angle) mode operation, the device can be used for torque only as well as for angle rotation only.

[0080] According to a further embodiment, there is provided a method and apparatus to enhance the click sound that occurs when the set torque is reached. In Step “7” of a typical torque wrenches enumerated above, the clicking mechanism provides both tactical feel (sudden drop of resistive force) and also an audible metal to metal knocking sound. However, both the tactile and audio feedback are very weak at the lower target torque settings. In a noisy environment, it is especially very poor at the rated 20% torque setting. If the operator encounter this problem, he/she may not be able to release the force immediately after click and end up in “over-torquing” the fastener resulting in not able to assemble mating parts to required specification.

[0081] In order to enhance the feedback to the user, one embodiment of the invention may use click detection hardware (see FIG. 5 for an example), including a 3-axis accelerometer, visual, audio and haptic feedback, to sense the metal-to-metal knocking sound and generate (i) a high pitch buzzer sound, (ii) vibration by switching on the miniature DC motor, and/or (iii) high intensity red LED. According to this embodiment, the user will be able to easily and reliably recognize the end of target torque application, especially in a noisy environment.

[0082] According to a further embodiment of the invention, the transition between application of desired torque and rotation to the post-torque angle of rotation may be automated, see FIG. 6. According to this embodiment, steps “1” through “9” are same as above, but Step “8” which requires the end user to manually press the mode button to enter angle mode is replaced by using data from the accelerometer as follows: [0083] a. Data from the 3-axis MEMS accelerometer is monitored immediately once torque and post-torque angle parameters are set by the user. (See, e.g., Capture, Synchronize, Calculate axis data and Slope>Thresh steps of FIG. 6). [0084] b. The mechanical metal-to-metal knock that occurs when the preset torque is reached (corresponding to the familiar “click”) is detected and confirmed using the algorithm of FIG. 6. See also FIGS. 7 and 8. [0085] c. Once the clicking action is detected and confirmed, the apparatus will switch over to Angle mode automatically. The screen will display the Target angle and the user now can continue with the application of angle.

[0086] The automated transition of torque to post-torque angle significantly minimizes down time and enhances productivity.

[0087] The innovations described herein are equally applicable to split beam torque wrenches which also generate a metal to metal knock (click) similar to typical mechanical Clicker torque wrenches. The main advantage of Split Beam over Mechanical Clickers is that they do not use springs that require (for optimal and accurate long term use) time consuming loading and unloading after each use. Therefore the Split Beam wrenches are preferred in applications where the time required for loading and unloading of the spring of Clicker type wrenches is not acceptable. However, a typical Split Beam Torque wrench has several limitations (i) resolution of scale is coarse, (ii) the minimum increments of torque values on the scale is coarse (10 ft-lb) per division, (iii) lack high viz display of scale, (iv) inability to set target torque accurately, (v) can only be used in either clockwise or counterclockwise only, and (vi) inability to use in a situation where the tightening specification calls for torque followed by angle of rotation.

[0088] Referring to FIG. 9A, a split beam torque wrench according to the invention has a pivoting head, a wrench body including a main beam, an anchor beam and a releasable catch between the main beam and the anchor beam, a handle, printed or stamped torque indicator markings, printed or stamped torque scale, rotary torque setting knob, knob enclosure. According to an embodiment of the invention, the printed or stamped torque indicator markings and torque scale may be replaced or supplemented by electronic controller housing, TFT display dynamic color (showing a preset angle of 135 degrees), unit key, mode key, scroll up key, scroll down key and power button. The setting of torque is sensed by using a rotary sensor (for example a rotary potentiometer) and displayed on the display. This method overcomes the (i) poor resolution, (ii) coarse increments, (iii) lack of high viz display, and (iv) inability to set target torque accurately.

[0089] According to a further embodiment, the split beam torque wrench may be provided with an angle sensor and microcontroller for receiving angle-of-rotation data, computing when a preset angle of rotation has been reached, and alerting the user when the preset angle or rotation has been achieved.

[0090] According to yet another embodiment of the invention, there is provided a torque wrench with improved accuracy and longevity. Prior art clicker-type torque wrenches include a ratchet head with a long tail body ending with a slot to accommodate a tiltable pawl. The tiltable pawl is sandwiched between this and another pocket of the Cam. See FIG. 10. In typical clicker torque wrenches, the pawl seat is press-fitted to the hinge and hits the tube when the unit reaches target torque and clicks. With the pawl seat mounted at the tip of the hinge in this fashion, the pawl seat is impacted each time the device clicks. Over repeated use, this can result in microcracks at the interface of the press-fit and loss of alignment with the cam. The misalignment can lead to premature loss of accuracy. Referring to FIG. 11, there is further provided according to an embodiment of the invention, a modified configuration for the pawl seat that protects the pawl seat from hitting the tube every time the wrench clicks. As shown in FIG. 11, the pawl seat is recessed into the end of the hinge (and has a narrower profile than the end of the hinge) and therefore, every time the wrench clicks (when the target torque is reached) only the hinge end will hit the inside of the main tube. Since the pawl seat does not have to absorb impact load with to this arrangement, this embodiment therefore serves to maintain accuracy of the tool over a longer period of time.

[0091] According to yet another embodiment of the invention, there is presented a torque wrench design with significantly improved handle rotation for the setting of desired torque and for unloading the spring after use. Typical mechanical clicker torque wrench require the user to unlock the handle by either pulling, pushing, or rotating a lock collar and then rotating the handle until the target torque number is aligned with tip of the handle. It often requires a substantial amount of effort to rotate the handle, especially if the value of the target torque is equal to the maximum torque rating. Furthermore, this is exacerbated due to the requirement (for tool accuracy and longevity) that the torque wrench be winded down to the bottom of the scale after use for storage if the unit is not going to be re-used immediately.

[0092] One contributing factor for the effort required to rotate the handle to set the desired torque or to unwind the tool after use is the friction between the scale tube and the main tube, represented in FIG. 12. According to this further embodiment of the present invention, there is presented a modified design for the torque setting nut including a widened shoulder area (see FIG. 13) having an outer diameter sized so that it contacts the inside surface of the rotary scale tube as the rotary scale tube is rotated about the main tube. According to this configuration, the torque setting nut 23 will present a localized second point of contact between the Main tube and Scale tube resulting in only two localized points of contact between the Main tube and Scale tube (see FIG. 14), thereby eliminating contact throughout the overlapping lengths of Main tube and Scale tube characterized by the prior art. This improvement significantly reduces the effort required to set the target torque on repeated use by reducing the friction.

[0093] It will be appreciated by those skilled in the art that changes could be made to the preferred embodiments described above without departing from the inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as outlined in the present disclosure and defined according to the broadest reasonable reading of the claims that follow, read in light of the present specification.