Abstract:
A bumper includes a supporting member, a base, a flange, a connecting arm, and a resetting assembly. The base is fixedly connected to the supporting member. The connecting arm has a rotating portion rotatably positioned between the flange and the supporting member. The resetting assembly includes a resisting member and an elastic member. The resisting member is slidably connected to the supporting member. The elastic member is configured for producing an elastic force to drive the resisting member to resist the rotating portion of the connecting arm. One of the rotating portion and the resisting member defines a receiving groove, and the other one of the rotating portion and the resisting member defines a restricting protrusion rotatably engaging in the receiving groove.

Description:
BACKGROUND 
     1. Field of the Disclosure 
     The present disclosure relates generally to bumpers and, more particularly, to a multi-directional bumper for a manipulator. 
     2. Discussion of the Related Art 
     A manipulator is widely used in the manufacturing industry to achieve high machining efficiency. The manipulator is generally assembled to a machine tool. However, the manipulator may collide with other components of the machine tool, such as a worktable in a machining process, potentially damaging the manipulator. 
     A pressure sensor is assembled to the manipulator to avoid the collision of the manipulator and the worktable. When the manipulator touches the worktable, the pressure sensor produces a warning signal, and transfers the warning signal to a controller. The controller controls the manipulator to move away from the worktable, and continues the machining process. 
     However, the manipulator needs both the pressure sensor and the controller to prevent the manipulator from colliding with the worktable. Therefore, a manufacturing cost for the manipulator is high. 
     Therefore, a bumper which overcomes the above-described shortcomings is desired. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an assembled, isometric view of an embodiment of a bumper, the bumper including a base, a supporting member, a flange, a connecting arm, and a resetting assembly. 
         FIG. 2  is an exploded, isometric view of the bumper of  FIG. 1 . 
         FIG. 3  is an isometric view of the connecting arm of  FIG. 1 . 
         FIG. 4  is a cross-sectional view of the bumper of  FIG. 1 . 
         FIG. 5  is similar to  FIG. 4 , but the connecting arm rotating through an angle relative to the supporting member. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , an embodiment of a damper  100  includes a base  11 , a supporting member  12 , a flange  13 , a connecting arm  14 , a resetting assembly  15 , a plurality of first fastening members  118 , and a plurality of second fastening members  136 . 
     Referring also to  FIGS. 3 and 4 , the base  11  defines a plurality of assembling holes  112  in a periphery of the base  11 , configured for connecting to a moving shaft of a machining tool (not shown). A positioning portion  113  is formed on a middle part of the base  11 . The base  11  also defines a plurality of connecting holes  114  around the positioning portion  113 . In the illustrated embodiment, the base  11  is cylindrical shaped. 
     The supporting member  12  defines a receiving hole  122  in a first end, and an assembling portion  124  in a second end opposite to the first end. The supporting member  12  also defines a through hole  123  communicating the receiving hole  122  with the assembling portion  124 . The first end of the supporting member  12  further defines a plurality of threaded holes  127  around the receiving hole  122 . The second end of the supporting member  12  further defines a plurality of threaded holes  126  around the assembling portion  124 . In the illustrated embodiment, the supporting member  12  is substantially cylindrical shaped, and the assembling portion  124  is substantially semi-spherical shaped. 
     The connecting arm  14  includes a rod  141  and a rotating portion  142  formed on an end of the rod  141 . In the illustrated embodiment, the rotating portion  142  is substantially spherical shaped. A center O 1  of the rotating portion  142  is aligned with an axis of the rod  141 . The rotating portion  142  defines a substantially semi-spherical receiving groove  143  away from the rod  141 . An end of the rod  141  opposite to the rotating portion  142  is configured to connect to a claw for clutching a workpiece (not shown). 
     The flange  13  includes a connecting portion  131  and a restricting portion  133  formed in a middle part of the connecting portion  131 . The flange  13  defines a plurality of connecting holes  1314  in the connecting portion  131 . The restricting portion  133  defines a circular hole  1334  in a top. The restricting portion  133  supports the rotating portion  142  of the connecting arm  14  and allows the rotating portion  142  to rotate freely. The rod  141  extends through the circular hole  1334  of the restricting portion  13 . 
     The resetting assembly  15  includes a resisting member  151  and an elastic member  152 . The resisting member  151  includes a sliding portion  1511 . A supporting pole  1513  extends from a bottom surface of the sliding portion  1511 . A restricting protrusion  1515  extends from a top surface of the sliding portion  1511 . In the illustrated embodiment, the sliding portion  1511  is substantially cylindrical shaped, and the restricting protrusion  1515  is substantially semi-spherical shaped. The sliding portion  1511  is slidably received in the receiving hole  122  of the supporting member  12 . The restricting protrusion  1515  is rotatably received in the receiving groove  143  of the connecting arm  14 . The elastic member  152  is sleeved on the supporting pole  1513 . In the illustrated embodiment, the elastic member  152  is a compression spring. 
     In the illustrated embodiment, both the first fastening members  118  and the second fastening members  136  are screws. 
     In assembling the bumper  100 , the resisting member  151  is inserted into the receiving hole  122  of the supporting member  12 . The elastic member  152  sleeves on the supporting pole  1513  of the resisting member  151 . The base  11  is fixed to the first end of the supporting member  12  via the first fastening members  118 . The positioning portion  113  engages in the receiving hole  122  of the supporting member  12 . The elastic member  152  is resisted between the resisting member  151  and the supporting member  12 . The restricting protrusion  1515  extends in the through hole  123  of the supporting member  12 , and is partially received in the assembling portion  124 . The rotating portion  142  of the connecting arm  14  is positioned in the assembling portion  124  of the supporting member  12 , and the restricting protrusion  1515  is rotatably received in the receiving groove  143  of the connecting arm  14 . The flange  13  is sleeved on the connecting arm  14 , and is fixed to the second end of the supporting member  12  via the second fastening members  136 . Therefore, the rotating portion  142  is rotatably positioned between the flange  13  and the supporting member  12 . A rotating center of the connecting arm  14  is the center O 1  of the rotating portion  142 . 
     In use, the claw for clutching the workpiece is assembled to the connecting arm  14 . The base  11  is assembled to the moving shaft of the machine tool.  FIG. 4  shows the bumper  100  in a normal mode. An axis of the resisting member  151  is aligned with the axis of the rod  141 . A first contacting point P 1  of the resisting member  151  and the connecting arm  14  are aligned in the axis of the resisting member  151 . Therefore, a direction of an elastic force produced by the elastic member  152  is along the axis of the rod  141 . The connecting arm  14  should not vibrate during the machining process, because no rotating moment is produced. 
     Referring to  FIG. 5 , when the rod  141  of the connecting arm  14  collides with other components of the machine tool, such as a worktable, a collision force is produced between the worktable and the connecting arm  14 , and drives the connecting arm  14  to rotate around the center O 1  of the rotating portion  142 . Therefore, a rotating moment M 1  is produce between the worktable and the connecting arm  14 . A second contacting point P 2  of the resisting member  151  and the connecting arm  14  deviates from the axis of the resisting member  151 . The elastic member  152  compresses to absorb a collision force between the worktable and the connecting arm  14 . Since the second contacting point P 2  deviates from the axis of the resisting member  151 , a resetting moment M 2  is produced by a resisting force of the resisting member  151  and applied on the connecting arm  14 . A direction of the resetting moment M 2  is opposite a direction of the rotating moment M 1 . When the connecting arm  14  leaves the worktable, the rotating moment M 1  disappears. The connecting arm  14  rotates relative to the center O 1  of the rotating portion  142  driven by the resetting moment M 2 . When the axis of the resisting member  151  is aligned with the axis of the rod  141 , the resetting moment M 2  disappears and the connecting arm  14  stops rotating. 
     Since the elastic member  152  is compressed to absorb the collision force between the worktable and the connecting arm  14 , the connecting arm  14  is not easily damaged by a collision between the connecting arm  14  and the worktable. In addition, when the connecting arm  14  leaves the worktable, the connecting arm  14  can automatically return to an original position by the resetting assembly  15 . 
     It should be pointed out that a wear washer  16  can be positioned between the flange  13  and the rotating portion  142 . Therefore, wear and tear on the flange  13  and the rotating portion  142  can be limited. The wear washer  16  can be made of polyformaldehyde (POM) by injection molding. In addition, the rotating portion  142  may form a restricting protrusion replacing the receiving groove  143 , and the resisting member  151  would define a receiving groove replacing the restricting protrusion  1515 . The rotating portion  142  can be other shapes, such as a column. In that case, both the assembling portion  124  of the supporting member  12  and the flange  13  are semi-column shaped. The connecting arm  14  can only rotate relative to a central axis of the rotating portion  142 . 
     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.