Patent Application
20230364755
The present invention relates to hand tools and in particular to torque wrenches.
Often, fasteners used to assemble performance critical components are tightened to a specified torque level to introduce a “pretension” in the fastener. For example, high tensile-strength steel bolts used to fasten components of military vehicles, aerospace vehicles, heavy machinery, and equipment for petrochemical operations frequently have required torque specifications. As torque is applied to the head of the fastener, eventually, beyond a certain level of applied torque the fastener actually begins to stretch. This stretching results in pretension in the fastener which then holds the joint together. Overstressing fasteners can lead to their breakage whereas under-stressing bolts can lead to joint failure, leakage, etc. Furthermore, in situations where gaskets are being utilized between the components being joined, an unequally stressed set of fasteners can result in gasket distortion and subsequent problems like leakage. Accurate and reliable torque wrenches help insure that fasteners are tightened to the proper specifications.
Torque wrenches vary from simple mechanical types to sophisticated electronic types. There are several types of mechanical torque wrenches that are routinely used to tighten fasteners to specified torque levels. Of these, clicker type mechanical torque wrenches are very popular. Clicker type mechanical torque wrenches make an audible click to let the user know when a preset torque level has been achieved and simultaneously provide a feeling of sudden torque release to the user. One example of a clicker type torque wrench includes a hollow tube in which a spring and pawl mechanism is housed. The pawl is forced against one end of a bar that extends from a drive head. The bar and drive head are pinned to the hollow tube about a pivot joint and rotate relative thereto once the preset torque level is exceeded. The preset torque level is selected by a user by causing the spring to exert either greater or lesser force on the pawl. The force acts on the bar through the pawl to resist rotation of the bar relative to the hollow tube. As the torque exerted on the fastener exceeds the preset torque value, the force tending to cause the bar to pivot relative to the hollow tube exceeds the force preventing its rotation and the pawl “trips.” When released by the action of the pawl, the bar pivots and hits the inside of the tube, thereby producing a click sound and a sudden torque release that is detectable by the user. Typically, the preset torque values to assist the user in setting the torque wrench are permanently marked on a drum type scale that is visible through a window near or on the handle, or marked on the tube itself. For most clicker type torque wrenches, the preset torque is set by rotating either an adjuster sleeve on the handle, an end cap, or a thumb screw.
Another example of a clicker type torque wrench (a so-called “split-beam” torque wrench) measures the deflection of a deflectable beam relative to a non-deflectable beam, the deflectable beam causing a click once the preset torque is reached. These and other types of clicker type mechanical torque wrenches are popular since they are relatively easy to operate and make torquing relatively quick and simple. The user merely sets the preset torque value and pulls on the handle until he/she hears and feels the click and torque release indicating to the user to cease torquing the fastener.
Several drawbacks limit the usage of clicker type torque wrenches. Often, these torque wrenches have permanently marked gages that are read by the user when setting the preset torque value. These gages can be hard to read, especially when the user is occupied with torquing a fastener with smooth and continuous motion to achieve proper fastening. Some existing torque wrenches address this issue by incorporating a magnifying glass or using a separate high resolution secondary scale. Still, the size of the markings is often small and the resolution of the markings is often limited by the physical space available on the gage. As well, the lack of high resolution may prevent the user from being able to preset to a desired torque value that includes a fraction of the desired units. Furthermore, these torque wrenches are often used in hard to reach, poorly lit areas, such as under the hood of an automobile, making readings potentially even more difficult.
As well, since the drum or other type of permanently marked gage can be fairly small, the upper torquing range of clicker type torque wrenches can be limited to less than the capability of the other mechanical parts of the wrench. Furthermore, in most prior art clicker type torque wrenches, the gages are marked with only one or two sets of units (i.e. foot-pounds and Newton-meters). The user is therefore limited to these two units and anything else is normally calculated manually.
Recalibration of existing clicker type torque wrenches, especially spring type clickers, often requires disassembling the unit to replace worn out parts, which can be expensive and time consuming. Recalibration is often needed to correct the effect of the spring's characteristics and mechanical wear that occurs over time. Often, such wear cannot be compensated for without recalibration since the gages are most often permanently printed on the handle.
While mechanical torque wrenches having electronic sensors and displays have been introduced to address the disadvantages of permanent marked gauges on the body of the device, such devices suffer the disadvantage of not being operable without batteries.
Additionally, it is now becoming common that an assembly specification requires the application of a specified torque followed by a further rotation of the fastener according to a specified angle of rotation. Current clicker torque technologies require different tools, a first tool to apply the torque and a second tool to apply additional rotation to the specified angle.
The present invention recognizes and addresses the foregoing considerations, and others, of prior art constructions.
An new improved hybrid torque wrench (hereinafter referred to as “Click-to-Angle”) is therefore provided having one or more of the following features to combine torque application and angle application in a single unit:
Each of these embodiments may be used independently or in combination with one or more of the other embodiments. Every combination and sub-combination of the above-listed embodiments is considered to be within the scope of the inventions described herein
According to a first basic embodiment of the present invention there is provided a mechanical torque wrench for engaging a workpiece, the torque wrench including a main tube defining an elongated interior compartment and a wrench head including a workpiece engaging portion and a bar extending therefrom. The wrench head is pivotally secured to a first end of the main tube at a pivot joint. The bar extends into the interior compartment and the workpiece engaging portion extends outwardly from the main tube. A hand grip is located on a second end of the main tube and a set spring is disposed within the interior compartment of the main tube. A tilting pawl is disposed between a rear face of the bar and the set spring. A torque setting screw is threadably received within the interior compartment of the main tube such that the torque setting screw moves along a longitudinal axis of the main tube when rotated. Rotation of the torque setting screw in a first direction compresses the set spring and rotation in a second direction allows expansion of the set spring. A lock ring is positioned adjacent the hand grip and is operatively connected to the torque setting screw and rotatable relative to the main tube. A resistive element is operatively coupled to the torque setting screw and produces an output signal, the output signal being dependent on the position of the torque setting screw relative to the resistive element. An electronic controller converts the output signal into an equivalent torque value that indicates a preset torque to be applied by the mechanical torque wrench to the workpiece. A user interface includes a display for displaying the equivalent torque value. When application of the preset torque is reached, the electronic controller first detects the mechanical “click” event and secondly sends an activation signal to audio, visual and/or haptic devices to notify the user that the preset torque has been reached.
According to a second basic embodiment (split beam torque wrench), there is provided a mechanical torque wrench for engaging a workpiece including a head that couples to a socket to rotate a workpiece. A housing extends from the head to form a handle. Within the housing forming the handle are two beams: a lever beam that transmits the force from the handle to the head and a deflecting beam that couples to the head and not the handle. The deflecting beam deflects away from the lever beam to indicate that a predetermined torque has been applied. A torque adjustment assembly moves the lever beam relative to the head to set the predetermined torque, and a pin follows the linear display to indicate to the user the set predetermined torque.
According to a first enhanced embodiment, the first or second basic embodiment described above may include an inertia sensing device, for example a gyro or an accelerometer, coupled to a microcontroller. The inertia sensing device transmits inertial data to the microcontroller which determines angle of rotation of the tool and transmits it to the display for displaying angle of rotation. According to preferred embodiments, a user may set a desired angle of rotation in an input device coupled to the microcontroller, and the microcontroller may output a “set angle of rotation achieved” signal to an audio, display and/or haptic device when the wrench has been rotated to the preset angle of rotation.
While the term microcontroller is used throughout this disclosure to refer to a device with processing functionality, it should be understood that any device that can perform the functions of a microcontroller may be substituted for the microcontroller(s) described herein without departing from the scope or intent of the invention.
According to another embodiment, the first enhanced embodiment may further include a second enhanced embodiment characterized by an automatic transition from application of torque to post-torque angle of rotation. According to this embodiment, the microcontroller may be configured to receive input instructions from the user via the input device for both desired application of torque and post-torque angle of rotation. Once the desired values are set, the user will commence application of torque and once the preset torque value has been reached, the device will detect when the preset torque has been achieved using an inertial sensor, gyro or accelerometer, may or may not make an visual, sound or haptic notification of “preset torque achieved,” and allow the user to continue rotation of the tool without pausing until the preset post-torque angle of rotation has been reached, at which time the microcontroller will cause the audio, display or haptic device to signal the user.
According to another embodiment, the first basic embodiment, the first enhanced embodiment and/or the second enhanced embodiment may further include a third enhanced embodiment in which physical torque indicators (such as scale) are printed, stamped, etched, embossed, engraved, painted or otherwise placed on the main tube/housing and on handle in order to permit use of the application of desired torque in the absence of batteries.
According to another embodiment, the first basic embodiment, the first enhanced embodiment, the second enhanced embodiment, and/or the third enhanced embodiment may further include a fourth enhanced embodiment characterized by a low profile design in which a PCB spacer element (e.g., a tube, bar, or rod) is placed between the torque setting screw and the set spring. The PCB spacer element has a narrower diameter than the main tube, and the resistive element interfaces directly with the spacer element rather than with the torque setting screw. With this method both the tracer of the resistive element and the PCB spacer are translating and therefore the sensing accuracy is improved and wear and tear are minimized. As the torque setting screw is rotated, the PCB spacer is forced forward and backward driving the resistive element with it. With the resistive element recessed into the body of the tool by virtue of the narrow profile spacer element, the printed circuit board and display can likewise be lowered toward the longitudinal axis of the device, providing an overall smaller profile.
According to another embodiment, the first basic embodiment, the second basic embodiment, the first enhanced embodiment, the second enhanced embodiment, the third enhanced embodiment and/or the fourth enhanced embodiment may include a fifth enhanced embodiment providing increased sound, visual and/or haptic feedback to the user when preset torque and/or preset angle of rotation has been achieved. According to this feature, an inertial sensor, for example a gyro or an accelerometer, and microcontroller may be configured to detect the physical “click” that occurs when a clicker-type torque wrench reaches the preset torque, and cause an audio, visual display or haptic device to signal the user that the preset torque has been achieved. Similarly, the inertial sensor and microcontroller may similarly cause an audio, visual display or haptic device to signal the user when the preset angle of rotation has been reached.
According to yet another embodiment, the first basic embodiment, the first enhanced embodiment, the second enhanced embodiment, the third enhanced embodiment, the fourth enhanced embodiment, and/or the fifth enhanced embodiment may include a sixth enhanced embodiment in which the pawl seat at the end of the hinge is recessed into the end of the hinge with a profile that is narrower than the end of the hinge. According to this feature, each time the set torque is achieved, only the end of the hinge contacts the inside surface of the main tube, producing less wear on the pawl seat, preserving device accuracy and increasing device longevity.
According to yet another embodiment, the first basic embodiment, the first enhanced embodiment, the second enhanced embodiment, the third enhanced embodiment, the fourth enhanced embodiment, the fifth enhanced embodiment and/or the sixth enhanced embodiment may include a seventh enhanced embodiment in which the nut (herein referred to as torque setting nut) in the main tube which receives the torque setting screw is situated at an end of the main tube and has a shoulder portion that extends longitudinally past the end of the main tube and extends radially beyond the outside surface of the main tube to contact the inside surface of the scale/handle tube. According to this embodiment, there are only two points of contact between the main tube and the scale tube, and rotation of the scale tube relative to the main tube is rendered less difficult for the user.
According to yet another embodiment, which may be used with any one or more of the above-described embodiments, a toque limiting spacer is provided in a narrowed section of the main tube, the length of which is arranged so that when the rated torque of the tool is reached, the end of the spacer contacts the main tube and any additional rotation beyond the rated torque is transmitted through the spacer.
According to yet another embodiment, which may be used with any one or more of the above-described embodiments, an enhanced visual display is provided with one or more of the following: vivid colors, real-time dynamically scaled font sizes to minimize human error, and real-time changing background colors to indicate critical steps during application of torque and angle.
It is contemplated and should be understood by all others that any one of these improvements may be used individually and/or in any combination with any one or more of the other improvements in any combination and sub-combination. Stated another way, each of these improvements is considered to be an invention, and every combination of one or more of these improvements is likewise considered to be an invention.
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:
Features in the attached drawings are numbered with the following reference numerals:
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.
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:
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.
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.
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
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
In the preferred configuration shown in the previous disclosure, the torque wrench operates as follows:
With this, the application of Click-to-Angle of the fastener is completed.
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.
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.
In order to enhance the feedback to the user, one embodiment of the invention may use click detection hardware (see
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
The automated transition of torque to post-torque angle significantly minimizes down time and enhances productivity.
According to a further embodiment of the invention, a rated-torque limiting spacer may be provided to prevent damage to sensitive parts of the tool when the tool is used over its rated torque. Consider the case where a specific torque application is specified, for example 45 ft lb, followed by rotation of 90 degrees. Consider further that the user selects a tool for the job that is rated at 100 ft lbs. Where the selected tool is suitable for application of the initial torque of 45 ft lb, the additional rotation of 90 degrees may take the tool beyond its rated torque, thus potentially damaging sensitive parts of the tool. This embodiment, see
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.
Referring to
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.
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
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.
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
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.
| Number | Date | Country | |
|---|---|---|---|
| 63333193 | Apr 2022 | US |
