Patent Publication Number: US-2022212350-A1

Title: Precision clamping assembly

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a clamping assembly, and more particularly to a precision clamping assembly with a simple structure, which can provide a multi-directional clamping effect, and can accurately monitor the state of a clamped object. 
     Description of Related Art 
     Conventional clamping assemblies, such as tweezers, clamps, or robotic arms, can mostly provide a clamping effect for objects. Among them, the tweezers or clamps are mainly composed of two clamping arms connected with each other. The two clamping arms can be moved toward or away from each other to clamp an object by an external force. However, the tweezers or clamps can only use the two clamping arms moved toward or away from each other in a straight line to clamp the object in a single direction (one-dimension), and cannot provide a deflection or rotation (multi-direction/three-dimensions) effects for the clamped object. 
     For example, a conventional precision clamping mechanism has a gripper module and a sensing module. The gripper module has a fixed side claw and a movable side claw, which is driven by a stepping or servo motor to linearly control a distance between the fixed side claw and the movable side claw. Although the above-mentioned conventional precision clamping assembly can provide a precise clamping effect to the object, it can only provide a clamping effect in a single direction, which limits the applicability of the tweezers or clamps, and relatively limits the practicability of the tweezers or clamps. Although the robotic arms can provide a deflection or rotation effect to the clamped object, the robotic arms have a complicated structure, which will relatively increase the time and cost of use, assembly, and maintenance. 
     Furthermore, the conventional clamping assembly can move the clamped object between two relative positions. The state of the clamped object can be confirmed or monitored by positioning or image detection at the relative positions but it cannot accurately confirming the state of the clamped object during the clamping movement. The user cannot accurately confirm or monitor the actual state of the clamped object, especially if the clamped object is a wafer, a probe, an electronic part or a small component, and the clamped object may fall or swing easily during the clamping movement, which increases the difficulty and inconvenience of clamping, moving, and monitoring the clamped objects. 
     To overcome the shortcomings, the present invention tends to provide a precision clamping assembly to mitigate or obviate the aforementioned problem. 
     SUMMARY OF THE INVENTION 
     The main objective of the invention is to provide a precision clamping assembly with a simple structure, which can provide a multi-directional clamping effect, and can accurately monitor the state of a clamped object. 
     The precision clamping assembly in accordance with the present invention has a body, two clamping arms, and a drive device. The body has a first direction, a second direction, a chamber formed in the body, and an opening formed through an outer side of the body along the second direction and communicating with the chamber of the body. The two clamping arms are pivotally connected to the body, and each one of the two clamping arms is disposed in the chamber and has a pivot end pivotally disposed in the chamber and a clamping end extended out of the body via the opening. The clamping ends are selectively moved toward or away from each other along the second direction and selectively moved same or opposite from each other along a third direction. The drive device is connected to the body and the two clamping arms, and has two driving sets disposed in the body and respectively connected to the two clamping arms to and drive the two clamping arms to move along the second direction and the third direction. 
     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a precision clamping assembly in accordance with the present invention; 
         FIG. 2  is another perspective view of the precision clamping assembly in  FIG. 1 ; 
         FIG. 3  is a top side view of the precision clamping assembly in  FIG. 1 ; 
         FIG. 4  is a side view of the precision clamping assembly in  FIG. 1 ; 
         FIG. 5  is a front side view of the precision clamping assembly in  FIG. 1 ; 
         FIG. 6  is an operational top side view of the precision clamping assembly in  FIG. 1 ; 
         FIG. 7  is an operational side view of the precision clamping assembly in  FIG. 1 ; and 
         FIG. 8  is an operational front side view of the precision clamping assembly in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     With reference to  FIGS. 1 to 5 , a precision clamping assembly in accordance with the present invention has a body  10 , two clamping arms  20 , a drive device  30 , and a monitoring device  40 . 
     The body  10  has a first direction D 1 , a second direction D 2 , a chamber  11 , an opening  12 , two through slots  13 , and two pivot holes  14 . The first direction D 1  may be a lengthwise direction of the body  10 , and the second direction D 2  may be a widthwise direction of the body  10 . The chamber  11  is formed in the body  10 . The opening  12  is formed through an outer side of the body  10  along the second direction D 2  and communicates with the chamber  11  of the body  10 . The two through slots  13  are formed in the chamber  11  of the body  10  along the first direction D 1  at a spaced interval, and each one of the two through slots  13  communicates with the opening  12 . The two pivot holes  14  are formed in an inner wall of the body  10  at a spaced interval and away from the opening  12 , and each one of the two pivot holes  14  communicates with one of the two through slots  13 . 
     The two clamping arms  20  are pivotally and movably connected to the body  10 , and each one of the two clamping arms  20  is disposed in the chamber  11  of the body  10  and has a pivot end  21  and a clamping end  22 . Each pivot end  21  of the two clamping arms  20  is pivotally disposed in the chamber  11  of the body  10 , and each clamping end  22  of the two clamping arms  20  extends out of the body  10  via the opening  12 . Additionally, each one of the two clamping arms  20  is disposed in one of the two through slots  13  of the body  10 , and is guided and limited by the corresponding through slot  13 . Furthermore, each pivot end  21  of the two clamping arms  20  is connected to one of the two pivot holes  14  of the body  10 , and the clamping arm  20  can pivot relative to the body  10 . 
     The clamping ends  22  of the two clamping arms  20  can be moved toward or away from each other along the second direction D 2 , and can be moved same or opposite from each other along a third direction D 3 . The third direction D 3  has two included angles respectively between the first direction D 1  and the second direction D 2  of the body  10 . Preferably, each one of the two included angles is 90 degrees. In addition, a horizontal imaginary extension line H is defined between the clamping ends  22  of the two clamping arms  20  along the second direction D 2 . 
     The drive device  30  is connected to the body  10  and the two clamping arms  20 , and has two driving sets  31 . The two driving sets  31  are disposed in the body  10 , are respectively connected to the two clamping arms  20 , and each one of the two driving sets  31  has a first driving element  32  and a second driving element  33 . The first driving element  32  is disposed in the chamber  11  of the body  10  along the first direction D 1 , and abuts against one of the two clamping arms  20  to enable the corresponding clamping arm  20  to move along the third direction D 3 . Each second driving element  33  of the two driving sets  31  is connected to one of the two clamping arms  20  to enable the corresponding clamping arm  20  to move along the second direction D 2  of the body  10 . 
     Furthermore, each one of the first driving elements  32  and the second driving elements  33  is a sheet or film made of a piezoelectric material, and the piezoelectric material may be the piezoelectric single crystal, the piezoelectric polycrystalline, the piezoelectric polymer or the piezoelectric composite material. A voltage generated by the drive device  30  after being energized enables each one of the first driving elements  32  and the second driving elements  33  to produce a mechanical deformation according to the piezoelectric effect, so that the corresponding clamping arm  20  moves along the second direction D 2  and the third direction D 3 . Then the two clamping arms  20  are moved toward or away from each other along the second direction D 2 , and are deflected along the third direction D 3 . Preferably, each clamping end  22  of the two clamping arms  20  is metal tweezers, and the metal tweezers are combined one of the second driving elements  33 . The two clamping arms  20  can clamp an object in a manner same as tweezers. 
     The monitoring device  40  is disposed on the body  10  and has an image capture module  41  disposed toward the clamping ends  22  of the two clamping arms  20  to detect or record an actual state of an object that is clamped between the two clamping ends  22  during a clamping movement. 
     As aforementioned, in use, with reference to  FIG. 6  of the precision clamping assembly in accordance with the present invention, when the second driving elements  33  of the two driving sets  31  are energized, the two clamping ends  22  respectively connected to the two second driving elements  33  are moved toward each other along the second direction D 2  of the body  10  to clamp an object. The above-mentioned operation mode can also drive only one of the second driving elements  33  so that the responsive one of the clamping ends  22  is moved toward the other clamping end  22 . Therefore, the present invention is not limited to that the two second driving elements  33  or each one of them is energized at the same time, as long as the distance between the two clamping ends  22  along the second direction D 2  can be changed to clamp the object. When the two clamping ends  22  clamp the object, in the subsequent movement process, the object held by the two clamping ends  22  can be detected and observed by the image capture module  41  of the monitoring device  40 , and the actual state of the object in the movement process can be obtained accurately in real time. In addition, after clamping and moving of the object, the power to each one of the second driving elements  33  is released, the second driving elements  33  can be moved back to the original locations. 
     With reference to  FIGS. 7 and 8 , when the clamping ends  22  of the two clamping arms  20  are moved by the two second driving elements  33  or by one of the two second driving elements  33  to clamp an object  50 , one or two of the first driving elements  32  can be energized to enable one or two of the two clamping arms  20  to swing relative to the body  10  along the third direction D 3  with the pivot ends  21  as a fulcrum. Then the object  50  clamped between the two clamping ends  22  of the clamping arms  20  is deflected or rotated between the two clamping ends  22  due to a relative displacement generated between the two clamping ends  22  along the third direction D 3 . 
     According to the above-mentioned features and structural relationships of the precision clamping assembly of the present invention, in use, the two clamping arms  20  are pivotally disposed in the body  10  and are driven by the drive device  30 . Then the two clamping arms  20  can clamp the object  50  along the second direction D 2  as shown in  FIG. 6 , and can deflect or rotate the object  50  due to the relative displacement between the two clamping ends  22  along the third direction D 3  to produce multi-directional (three-dimensions) deflection or rotation effect (small size range) to the object  50  as shown in  FIGS. 7 and 8 . Furthermore, the body  10  can be connected to or assembled on other tools or drive devices, so that the body  10  can be moved or rotated along the first direction D 1  through the transmission of the aforementioned components (large size range), which enables the precision clamping assembly of the present invention to provide a multi-directional clamping effect to the object  50 . Compared with the conventional robotic arms, the precision clamping assembly of the present invention was created with fewer components and a simplified structure, so it can greatly reduce the time and cost for use, assembly, and maintenance. 
     In addition, the clamping ends  22  of the two clamping arms  20  of the precise clamping assembly of the present invention can clamp the object  50  at different angles according to the shape (regular/irregular) of the object  50  by the first driving elements  32  and the second driving elements  33  of the two driving sets  31  to greatly improve the applicability of the precision clamping assembly. 
     Furthermore, the first driving elements  32  and the second driving elements  33  of the precision clamping assembly of the present invention can be made of piezoelectric materials and can be energized to accurately control the movement or deflection of the clamping ends  22  of the two clamping arms  20 . With reference to  FIG. 8 , each clamping end  22  of the two clamping arms  20  can move 0 to 600 micrometers (um) upward along the third direction D 3  based on the horizontal imaginary extension line H, and can also move 0 to 400 micrometers (um) downward along the third direction D 3  based on the horizontal imaginary extension line H. Consequently, the two clamping arms  20  of the precision clamping assembly of the present invention can clamp, deflect or rotate small objects  50  such as wafers, probes or electronic parts to provide a precise clamping effect. 
     Additionally, the monitoring device  40  disposed on the body  10  can captured images of the object  50  clamped between the clamping ends  22  by the image capture module  41  to detect and observe the actual state of the object  50  in real time during the movement process accurately and to effectively avoid the problem of the conventional clamping assembly. 
     Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.