Abstract:
A balancing mechanism for a robot configured for lifting heavy weights comprises a hollow balancing body comprising an opening; an elastic assembly received in the balancing body and a pulling rod assembly received in the balancing body and hinged to a robot arm of the robot. One end of the pulling rod assembly resists the elastic assembly, and another opposite end of the pulling rod assembly extends out from the balancing body through the opening, the pulling rod assembly is movably assembled with the balancing body via the elastic assembly to make the elastic assembly capable of producing a balancing moment against the gravity moment of the robot arm.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a balancing mechanism and a robot using the balancing mechanism. 
     2. Description of Related Art 
     Industrial robots used in manufacturing, assembling, painting and other areas are employed for bad environments or to do heavy or hard work. Robots with long arms may grasp and move heavy objects for an extended distance. However, a weight of these objects may be such that some robots with reduced balance and stability will be easily destroyed, or at least their precision working in the placement of objects will be disturbed. Balancing mechanisms are installed at these robots to improve the balance and stability thereof. The structures of the balance mechanisms in related art are complex. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of a robot. 
         FIG. 2  is a cross section of the robot of  FIG. 1 , taken along line II-II. 
         FIG. 3  is an isometric and exploded view of the robot of  FIG. 1 . 
         FIG. 4  is similar to  FIG. 3 , but viewed from another aspect. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , an embodiment of a robot  100  includes a base  10 , a deceleration machine  20 , a support body  30 , a first driving mechanism  40 , a robot arm  50 , a second driving mechanism  60  and a balancing mechanism  70 . The deceleration machine  20  is positioned at the base  10 . The support body  30  is rotatably connected with the deceleration machine  20 . The first driving mechanism  40  is installed at the support body  30  and connects with the deceleration machine  20  for driving the support body  30  to rotate relative to the base  10 . The robot arm  50  is rotatably positioned at the support body  30 . The second driving mechanism  60  is mounted at the support body  30  and connects with the robot arm  50  for driving the robot arm  50  to rotate relative to the support body  30 . The balancing mechanism  70  is mounted on the support body  30  and is hinged with the robot arm  50  for counter balancing the robot arm  50  and the base  10  to improve the balance of the robot  100 . 
     Referring also to  FIGS. 3 and 4 , the base  10  is used for installing the robot  100  to the floor or other place, and defines a first axis Al perpendicular to the base  10 . The deceleration machine  20  is positioned at the base  10 . 
     The support body  30  is rotatably connected with the deceleration machine  20 . The support body  30  includes a first connecting portion  31 , a second connecting portion  33 , and a third connecting portion  35 . The first connecting portion  31  is rotatably connected with the base  10  via the deceleration machine  20 . A mounting board  311  is formed at one end of the first connecting portion  31  which extends outward for installing the balancing mechanism  70 . The second connecting portion  33  extends up from another end of the first connecting portion  31  opposite to the mounting board  311  of the first connecting portion  31 . The third connecting portion  35  is an arcuate structure, extending from a top surface of the first connecting portion  31  and finally connecting with the second connecting portion  33  for enhancing the supporting effect. 
     The first driving mechanism  40  is positioned at the first connecting portion  31  of the support body  30  and connects with the deceleration machine  20 . The first driving mechanism  40  is used for driving the support body  30  to rotate around the first axis A 1 . A first direction X axis is substantially parallel to the first axis A 1 . The robot arm  50  includes a first mounting end  51  and a second mounting end  52  opposite to the first mounting end  51 . The first mounting end  51  is hinged with the second connecting portion  33  of the support body  30 . A pair of ears  53  is separately formed on a side surface of the first mounting end  51  and each ear  53  extends towards the mounting board  311 . A hinging hole  531  is defined through each ear  53 . The second mounting end  52  is used for connecting with other robot arms (not shown) or other mechanisms (not shown). The second driving mechanism  60  is mounted at the second connecting portion  33  and connects to the first mounting end  51 . The second driving mechanism  60  defines a second axis A 2 . The second axis A 2  is substantially perpendicular to the first axis A 1 . A second direction Y axis is substantially parallel to the second axis A 2 . A third direction Z axis is defined to be substantially perpendicular to X and Y axes. The second driving mechanism  60  is used for driving the robot arm  50  to rotate around the second axis A 2 . In this illustrated embodiment, the second axis A 2  is perpendicular to the first axis A 1 . The mounting board  311  is substantially parallel to Y and Z axes. 
     The balancing mechanism  70  is movably positioned at the mounting board  311  and hinges with the pair of ears  53  of the robot arm  50 . The balancing mechanism  70  includes a bracket  71 , a balancing body  73 , a pulling rod assembly  75 , an elastic assembly  78 , and a fixing element  79 . The bracket  71  is positioned at the mounting board  311  for supporting the balancing body  73 . The balancing body  73  is rotatably positioned at the top of the bracket  71  and above the mounting board  311 . The pulling rod assembly  75  is received in the balancing body  73  and extends toward the robot arm  50  to hinge with the two ears  53  via the fixing element  79 . The elastic assembly  78  is received in the balancing body  73 . 
     In the illustrated embodiment, the bracket  71  is a substantially U-shaped structure, which includes a fixing portion  711  and two supporting arms  713  extending from opposite sides of the fixing portion  711 . The fixing portion  711  is installed on the mounting board  311 . The fixing portion  711  extends along a direction substantially parallel to the Y axis. The fixing portion  711  is substantially parallel to the mounting board  311 . The two supporting arms  713  extend toward a same side of the fixing portion  711 . Each supporting arm  713  is inclined to a direction substantially parallel to the Z axis. The balancing body  73  is a substantially hollow cylinder, which includes a cylindrical housing  731  and a resisting member  735 . The housing  731  forms an opening  732 . Several fixing blocks  734  are separately formed at an outer round edge of the opening  732 . Two pivoting portions  737  are formed oppositely at an outer surface of the housing  731  corresponding to the two supporting arms  713  for fixing the housing  731  and the bracket  71  together. The resisting member  735  is assembled to cover the opening  732 . The resisting member  735  includes an outer surface  7351  and an inner surface  7355  opposite to the outer surface  7351 . A first through hole  7353  is defined at the middle of the resisting member  735 . A first annular resisting portion  7356  and a second annular resisting portion  7357  are separately formed at the inner surface  7355  around the first through hole  7353 . The second annular resisting portion  7357  is away from the through hole  7353  and adjacent to the edge of the inner surface  7355 . Several installing portions  7359  are formed at the flange of the resisting member  735  corresponding to the fixing blocks  734  for fixing the resisting member  735  to the housing  731 . 
     The pulling rod assembly  75  includes a holding member  751 , a pulling rod  752 , a clamping member  753  and a connecting block  759 . The holding member  751  is received in the housing  732 . The pulling rod  752  is also received in the housing  732  and extends from the first through hole  7353  to connect with the connecting block  759 . One end of the pulling rod  752  away from the connecting block  759  is connected to the holding member  751 . The holding member  751  is a circular plate and forms a holding surface  7511  facing the resisting member  735 . A second through hole  7513  is defined at the middle of the holding member  751 . A first holding portion  7515  and a second holding portion  7517  are formed at the holding surface  7511  to correspond to the first annular resisting portion  7356  and the second annular resisting portion  7357  of the resisting member  735 , respectively. 
     The pulling rod  752  includes a main body  7521 , a first linking portion  7523  and a second linking portion  7525 . The first linking portion  7523  and the second linking portion  7525  are positioned at two opposite ends of the main body  7521  and having smaller diameters than that of the main body  7521 . The main body  7521  passes through the second through hole  7513 . The second linking portion  7525  passes through the second through hole  7513 , and is finally fixed by the clamping member  753 , such that the holding member  751  is securely fixed in place. The connecting block  759  includes a joint  7591  and a mounting portion  7592  connected with the joint  7591 . The joint  7591  is hinged with the pair of ears  53 . A linking hole  7593  is defined in a center of the joint  7591  along an axis of the joint  7591  for hinging with the two ears  53 . The mounting portion  7592  has a smaller width than that of the joint  7591 . A mounting hole  7595  is defined at an end surface of the mounting portion  7592  away from the joint  7591 . One end of the first linking portion  7523  away from the main body  7521  is positioned in the mounting hole  7595 . In other embodiments, the holding member  751 , the pulling rod  752  and the connecting block  759  can be made integrally. 
     The elastic assembly  78  is received in the balancing body  73  and sleeves on the pulling rod  752 . The elastic assembly  78  is between the holding member  751  and the resisting member  735 . The elastic assembly  78  includes a first elastic member  781  and a second elastic member  785  received in the first elastic member  781 . Both the first and the second elastic members  781 ,  785  are coil springs and sleeve on the pulling rod  752 . The first elastic member  781  resists between the second annular resisting portion  7357  and the second holding portion  7517 . The second elastic member  785  resists between the first annular resisting portion  7356  and the first holding portion  7515 . In other embodiments, the elastic assembly  78  can be only one elastic member, or include several elastic members; the elastic assembly  78  can resist between a flange of the opening  732 , and the holding member  751 , and the resisting member  735  can be omitted; the elastic assembly  78  is not required to sleeve the passing rod  752 , the elastic assembly  78  may be just configured between the holding member  751  and the resisting member  735 . 
     In assembly, the deceleration machine  20  is positioned at the base  10 , the support body  30  is rotatably installed at the deceleration machine  20 , and the first mounting end  51  of the robot arm  50  is rotatably positioned at the second connecting portion  33  of the support body  30 . The first driving mechanism  40  and the second driving mechanism  60  are mounted on the support body  30 . The second linking portion  7525  passes through the second through hole  7513  and is finally fixed by the clamping member  753 . The elastic assembly  78  sleeves on the pulling rod  752 . The first linking portion  7523  passes through the resisting member  735  and goes into the mounting hole  7595  for connecting with the connecting block  759 . The holding member  751 , the pulling rod  752 , the clamping member  753  and the elastic assembly  78  are placed into the balancing body  73 , then the resisting member  735  is fixed to the balancing body  73  to cover the opening  732 . The bracket  71  is installed at the mounting board  311 , and the balancing body  73  is rotatably mounted at the two supporting arms  713 . Finally, the fixing element  79  passes through the hinging hole  531 , the mounting hole  7595 , and through another hinging hole  531  for hinging the connecting block  759  with the robot arm  50 . 
     When the robot  100  is working, the robot arm  50  rotates counterclockwise around the second axis A 2 . The pulling rod  752  is pulled to move and bring the holding member  751  toward the resisting member  735 . The elastic assembly  78  is compressed between the holding member  751  and the resisting member  735 . Then a moment is produced by the elastic force of the elastic assembly  78  for balancing the gravity moment of the robot arm  50   
     The balancing mechanism  70  has a very simple configuration arrangement, including only the balancing body  73 , the pulling rod assembly  75 , and the elastic assembly  78 . The elastic assembly  78  resists between the resisting member  735  and the holding member  751 . The holding member  751  can move toward the resisting member  735  to compress the elastic assembly  78  by means of the pulling rod assembly  75 . The elastic assembly  78  of the balancing mechanism  70  can produce a balancing moment against the gravity moment of the robot arm  50 . As a result, the balance and stability of a robot configured with the balancing mechanism  70  will be much improved. 
     It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its material advantages.