Patent Publication Number: US-11383361-B2

Title: Electro-mechanical torque wrench

Description:
FIELD OF THE INVENTION 
     The present invention relates to a torque wrench, and more particularly to an electro-mechanical torque wrench that has a mechanical trip structure and a function to display torque values digitally. 
     BACKGROUND OF THE INVENTION 
     With advantages of durability and high accuracy, mechanical torque wrenches are widely used by the public. In general, a mechanical torque wrench mainly has a main body. One end of the main body is provided with a working head, and the other end of the main body is provided with a grip. A trip mechanism is provided in the main body and connected to the working head. Therefore, when a user operates the mechanical torque wrench, the trip mechanism bears the torque transmitted by the working head. When the applied torque is greater than the torque value set by the user, the trip mechanism is released to produce a sound and vibration to prompt the user to stop operation. Furthermore, the mechanical torque wrench is provided with a torque adjustment mechanism. The torque adjustment mechanism includes a spring, which allows the user to adjust the torque value by adjusting the compression of the spring. 
     However, the conventional mechanical torque wrench has the following disadvantages. First, when the user applies force to the grip, the mechanical torque wrench cannot simultaneously display the present torque value, that is, the information of torque values from the initial applied force to the actuation of the trip mechanism cannot be obtained by the user. Second, the user needs to reset the preset torque value of the conventional torque adjustment mechanism to zero after each operation to avoid elastic fatigue caused by the continuous compression of the spring. However, this mechanism will cause inconvenience to users. Third, the torque adjustment mechanism is generally disposed at one side of the main body, which makes the user likely touch the torque adjustment mechanism by accident during operation. Fourth, the conventional trip mechanism has the spring against a roller, and the roller is against an inclined surface of the working head. When the applied torque is greater than the elastic force of the spring, the roller will be disengaged. However, this design is bulky, so the conventional mechanical torque wrench has insufficient space for accommodating a sensor. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide an electro-mechanical torque wrench that has a mechanical trip structure and a function to display torque values digitally. The electro-mechanical torque wrench is convenient for use and easy to read the torque values. Another object of the present invention is to provide an electro-mechanical torque wrench that allows a user to adjust a pre-set torque value by releasing an anti-misoperation unit, so as to prevent misoperation from touching by accident. 
     In order to achieve the primary object, the present invention provides an electro-mechanical torque wrench, comprising a main body. A trip mechanism is provided in the main body. The trip mechanism includes a long rod and a short rod arranged side-by-side. One end of the short rod is provided with a bearing portion. A rotatable releasing member is pivotally connected to a middle section of the long rod. One side of the releasing member, close to the short rod, is provided with a pressing portion corresponding to the bearing portion. Another side of the releasing member, away from the short rod, is provided with an extension portion. An elastic member is connected between the extension portion and the long rod, so that the releasing member is biased by elastic force of the elastic member for enabling the pressing portion to press against the bearing portion. Thereby, when the user intends to secure a workpiece and apply force to the grip, the long rod and the short rod of the electro-mechanical torque wrench are subject to torque to cause flex. When the torque reaches a preset torque value, the bearing portion is disengaged from the pressing portion to produce a mechanical sound and slight vibration to prompt the user to stop operation. A peripheral side of the long rod is provided with at least one strain sensor, and the strain sensor is electrically connected with a display module for sensing the amount of deformation of the long rod and transmitting the sensing information to the display module, so that the display module outputs a corresponding torque value in a digital display manner. 
     In order to achieve another primary object, the present invention provides an electro-mechanical torque wrench. The long rod is formed with a screw hole, and a screw rod is disposed in the screw hole. One end of the screw rod extends out of the main body and is provided with a knob. The knob is configured to drive rotation of the screw rod, so that the rotating screw rod enables the position of the long rod to be adjustable. The electro-mechanical torque wrench further comprises an anti-misoperation unit. The anti-misoperation unit includes a limiting member connected to the tubular body and an operating member disposed on the screw rod. The operating member enables to axially slide only along a displacement direction of the screw rod between a locked position and an unlocked position. When in the locked position, the operating member is confined by the limiting member, so that the screw rod cannot be rotated. When in the unlocked position, the operating member is disengaged from the limiting member, so that the screw rod is rotatable to adjust the preset torque. Thereby, the operating member of the anti-misoperation unit must be switched to the unlocked position by the user to make the knob rotatable for adjusting the preset torque, and the misoperation by accident can be avoided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view in accordance with a preferred embodiment of the present invention; 
         FIG. 2  is a cross-sectional view in accordance with the preferred embodiment of the present invention; 
         FIG. 3  is a cross-sectional view showing the torque adjustment mechanism according to the preferred embodiment of the present invention; 
         FIG. 4  is an exploded view showing the torque adjustment mechanism according to the preferred embodiment of the present invention; 
         FIG. 5  is another cross-sectional view showing the torque adjustment mechanism according to the preferred embodiment of the present invention; and 
         FIG. 6  is a schematic view showing the operation of the preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings. 
       FIG. 1  is a perspective view in accordance with a preferred embodiment of the present invention.  FIG. 2  is a cross-sectional view in accordance with the preferred embodiment of the present invention. The present invention discloses an electro-mechanical torque wrench  100 . The electro-mechanical torque wrench  100  includes a main body  10  having a hollow tubular body  11 . One end of the tubular body  11  is provided with a working head  12 , and the other end of the tubular body  11  is provided with a grip  13 . The tubular body  11  has a chamber  111  therein. A trip mechanism  20  is accommodated in the chamber  111 . An outside of the tubular body  11  close to the grip  13  is formed with at least one shaft hole  112  that is in communication with the chamber  111 . A torque adjustment mechanism  30  is insertedly disposed in the shaft hole  112 . A digital display unit  40  is disposed on the outside of the tubular body  11  close to the grip  13 . In this embodiment, the digital display unit  40  is disposed between the shaft hole  112  and the grip  13 . 
     Referring to  FIG. 2 , the trip mechanism  20  includes a long rod  21  and a short rod  22  arranged side-by-side in the chamber  111 . One end of the long rod  21  is inserted and disposed in a first connecting hole  121  of the working head  12 , and the other end of the long rod  21  extends along an axial direction of the tubular body  11  to a position adjacent to the shaft hole  112  and is formed with a screw hole  211  corresponding to the shaft hole  112 . One end of the short rod  22  is inserted and connected to a second connecting hole  122  of the working head  12 , and the other end of the short rod  22  extends along the axial direction of the tubular body  11  to a position near a middle section of the long rod  21 . The other end of the short rod  22  is provided with a bearing portion  221 . The trip mechanism  20  further includes a releasing member  23  located at the middle section of the long rod  21 . One end of the releasing member  23  is pivotally disposed at the long rod  21  through a pivot pin  212  and rotatable relative to the long rod  21 , and the other end of the releasing member  23  extends toward the short rod  22 . A pressing portion  231  is disposed at the other end of the releasing member  23 , and the pressing portion  231  faces toward the short rod  22  and corresponds to the bearing portion  221 . The pressing portion  231  of the releasing member  23  is close to the short rod  22 . An extension portion  232  opposite to the pressing portion  231  is disposed at the other end of the releasing member  23 , and the extension portion  232  of the releasing member  23  is away from the short rod  22 . The trip mechanism  20  further includes an elastic member  24 , such as a compression spring. One end of the elastic member  24  is accommodated in a counterbore  213  disposed at the long rod  21 , and the other end of the elastic member  24  is connected to the extension portion  232 , so that the releasing member  23  is biased by elastic force of the elastic member  24  for enabling the pressing portion  231  to continuously press against the bearing portion  221 . In addition, the tubular body  11  is formed with a fixing hole  113  communicating with the chamber  111  and corresponding to the releasing member  23 . The trip mechanism  20  has an abutment member  25  disposed in the fixing hole  113  and including an abutment rod  251  extending toward the extension portion  232 . Thereby, when the user intends to secure a workpiece and apply force to the grip  13 , the long rod  21  and the short rod  22  of the electro-mechanical torque wrench  100  are subject to torque to cause flex. With the increase of applied force, the releasing member  23  gradually approaches the abutment member  25 . When the torque reaches a preset torque value, the extension portion  232  of the releasing member  23  is blocked by the abutment member  25  and pivotally rotates about the pivoting pin  212  in a clockwise direction, so that the bearing portion  221  is disengaged from the pressing portion  231  to produce a mechanical sound and slight vibration to prompt the user to stop operation. Since the long rod  21  and the short rod  22  of the trip mechanism  20  are non-spring mechanisms, the elastic fatigue will not occur in the electro-mechanical torque wrench of this invention. After use, there is no need to reset the preset torque value of the torque adjustment mechanism  30  to zero, thereby greatly improving convenience of use. 
       FIG. 3  is a cross-sectional view showing the torque adjustment mechanism according to the preferred embodiment of the present invention. The torque adjustment mechanism  30  has a screw rod  31  passing through the shaft hole  112  and the screw hole  211 . One end of the screw rod  31  extends out of the shaft hole  112  and is provided with a knob  32 . Preferably, two shaft holes  112  are respectively disposed at two sides of the tubular body  11 , and the shaft holes correspond to each other. The other end of the screw rod  31  is provided with an end cap  33 . The end cap  33  is fixed to the shaft hole  112  at the other side of the tubular body  11 . When the screw rod  31  is driven for rotation by the knob  32 , the long rod  21  is movable along an insertion direction of the screw rod  31  for the reason that the screw rod  31  is engaged with the screw hole  31  of the long rod  21 . Accordingly, the preset torque value of the electro-mechanical torque wrench  100  can be adjustable. 
       FIG. 4  is an exploded view showing the torque adjustment mechanism according to the preferred embodiment of the present invention. Please also refer to  FIG. 2 . The digital display unit  40  has a display module  41  disposed on the outside of the tubular body  10 . At least one strain sensor  42  is electrically connected to the display module  41 . As shown in  FIG. 2 , the strain sensor  42  is arranged on a peripheral side of the long rod  21  for sensing the amount of deformation of the long rod  21  and transmitting the sensing information to the display module  41  so that the display module  41  outputs a corresponding torque value in a digital display manner. The two ends of the long rod  21  are connected to the torque adjustment mechanism  30  and the working head  12 , respectively. The torque adjustment of the torque adjustment mechanism  30  will result in displacement of the long rod  21 . When the work head  12  is used to secure the workpiece, the force applied by the user will cause the long rod  21  to flex. Therefore, based on the structure of the long rod  21  and the short rod  22 , the strain sensor  42  has to attach to the peripheral side of the long rod  21  for making the digital display unit  40  truly display its torque value. In addition, in case of the strain sensor  42  attached to the short rod  22 , when a predetermined torque is reached, the short rod  22  will be released and collide with an inner edge of the tubular body  11 . The vibration caused by the collision likely leads to damage of the strain sensor  42 . In this embodiment, the digital display unit  40  has a plurality of strain sensors  42 . The strain sensors  42  are symmetrically disposed on the peripheral side of the long rod  21 . Preferably, the long rod  21  has an upper face  21 A facing the short rod  22  and a lower face  21 B opposite the upper face  21 A. A first plural of the strain sensors  42  are disposed on the upper face  21 A and a second plural of the strain sensors  42  are disposed on the lower face  21 B. Owing to the applied force of the grip  13  from the user enables the upper face  21 A and the lower face  21 B to sustain more stress. When the long rod  21  is under force, the upper face  21 A and the lower face  21 B possess larger variation comparing to other faces of the long rod  21 . Therefore, the strain sensors  42  attached to the above-mentioned surfaces may obtain more accurate torque sensing values. A position sensor  43  close to the torque adjustment mechanism  30  is electrically connected to the display module  41 . The position sensor  43  and the screw rod  31  are connected through a driving mechanism  44 . In this embodiment, the driving mechanism  44  includes a first gear  441  connected to the screw rod  31 , a second gear  442  connected to the position sensor  43 , and a third gear  443  pivoted to the tubular body  11  and engaged between the first gear  441  and the second gear  442 . The first gear  441  is sleeved onto the screw rod  31 . The tubular body  11  is formed with a pivot hole  114 . The third gear  443  is provided with a rotating shaft  4431 . The rotating shaft  4431  is inserted in the pivot hole  114  to make the third gear  443  pivotally disposed at the tubular body  11 . Thus, the amount of variation of the screw rod  31  can be sensed and transmitted to the display module  41  via the position sensor  43 , so that the display module  41  outputs the corresponding preset torque value. Thereby, when the user operates the electro-mechanical torque wrench  100 , the torque value can be displayed in a digital display manner through the digital display unit  40 , which facilitates the user&#39;s interpretation. 
       FIG. 5  is another cross-sectional view showing the torque adjustment mechanism according to the preferred embodiment of the present invention.  FIG. 6  is a schematic view showing the operation of the preferred embodiment of the present invention. The tubular body  11  is formed with a plurality of positioning holes  115  close to the shaft hole  112 . The electro-mechanical torque wrench  100  further includes an anti-misoperation unit  50 . The anti-misoperation unit  50  includes a fixing member  51  disposed on the outside of the tubular body  11  and a limiting member  52  disposed in the chamber  111 . The fixing member  51  has an enlarged hole  511  corresponding to the shaft hole  112  and a plurality of perforations  512  corresponding to the positioning holes  115 . The limiting member  52  has a polygonal hole  521  corresponding to the shaft hole  112  and a plurality of locking holes  522  corresponding to the positioning holes  115 . The anti-misoperation unit  50  further includes a plurality of locking members  53 . Each of the locking members  53  is inserted in each of the corresponding perforations  512 , the positioning holes  115  and the locking holes  522 , respectively, so as to fix the fixing member  51  and the limiting member  52  to the tubular body  11 . In addition, an outer side of the knob  32  is recessed to form an accommodating trough  321 . A bottom of the accommodating trough  321  is further recessed to form a blind hole  311  extending into the screw rod  31 . An outer periphery of the screw rod  31  is formed with a slot  312  communicating with the blind hole  311 . The anti-misoperation unit  50  further includes an operating member  54  disposed on the tubular body  11 . The operating member  54  is accommodated in the accommodating trough  321  and has a shaft portion  541  inserted in the blind hole  311 . The shaft portion  541  is formed with a through hole  542  corresponding to the slot  312 . The through hole  542  is provided with a limiting pin  55 . An end of the limit pin  55  extends out of the through hole  542  and is located in the slot  312 , so that the operating member  54  enables to axially slide only along a displacement direction of the screw rod  31  between a locked position and an unlocked position. When the operating member  54  is in the locked position, as shown in  FIG. 5 , the limiting pin  55  is engaged and constrained in the polygonal hole  521  of the limiting member  52 , so that the screw rod  31  cannot be rotated. When the operating member  54  is in the unlocked position, as shown in  FIG. 6 , the limiting pin  55  is disengaged from the polygonal hole  521  of the limiting member  52 , so that the screw rod  31  is rotatable to adjust the torque. In addition, one end of the shaft portion  541 , located in the accommodating trough  321 , is enlarged to form a head  543 . The anti-misoperation unit  50  further includes a spring  56  sleeved onto the shaft portion  541 . Two ends of the spring  56  abut against the head  543  and an inner wall surface of and the accommodation trough  321 , respectively, so that the operating member  54  is biased by elastic force of the spring  56  and has a tendency from the unlocked state to the locked state. Thereby, the operating member  54  of the anti-misoperation unit  50  must be switched to the unlocked position by pressing the head  543  to make the knob  32  rotatable for adjusting the preset torque value, and the misoperation by accident can be effectively avoided. 
     Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims.