Abstract:
A device for vacuum-lifting workpieces includes a driving assembly, a rotating table, a plurality of suction assemblies mounted on the rotating table spaced from each other, and a vacuum pump. Each suction assembly includes a suction cup. An airflow guiding part is configured to align each suction cup with a vacuum when the suction cup is positioned above a picking station. The driving assembly makes the suction cups communicate with the airflow guiding part in succession. Each suction assembly is capable of picking a different type of workpiece, therefore the suction device can take the place of a plurality of individual manipulators.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to suction devices, especially relates to a suction device for vacuum-lifting multiple types of workpieces. 
     2. Description of Related Art 
     Assembling a keystroke of a cell phone may include the following steps: pasting a foam on an inner surface of the keystroke, and pasting a protecting film on an opposite outer surface of the keystroke. However, since the foam differs from the protecting film in shape or/and size, each of the above steps is required done by different manipulators. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Many aspects of the disclosure can be better understood with reference to the following figures. The components in the figures are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an exploded view of an exemplary embodiment of a suction device. 
         FIG. 2  is an assembled, schematic view of the suction device in  FIG. 1 . 
         FIG. 3  is similar to  FIG. 2  but viewed from another angle. 
         FIG. 4  is an enlarged view of a rotating table and a suction assembly of the suction device in  FIG. 1 . 
         FIG. 5  is a cross sectional view of an airflow guiding part of the suction device in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-3 , an exemplary embodiment of a suction device  100  used for vacuum-lifting multiple types of workpieces. The suction device  100  includes a fixing bracket  10 , a driving assembly  20 , a rotating table  30 , a plurality of suction assemblies  40  and a vacuum pump assembly  50 . The driving assembly  20 , the rotating table  30 , and the vacuum pump assembly  50  are mounted on the fixing bracket  10 . The plurality of suction assemblies  40  are mounted on the rotating table  30  and spaced from each other. The fixing bracket  10  is mounted to a manipulator (not shown), which positions the suction device  100 . 
     The fixing bracket  10  includes a connecting board  11 , a first arm  13 , and a second arm  15 . The first arm  13  and the second arm  15  are attached to two opposite ends of the connecting board  11  and spaced-apart from each other. The connecting board  11  is mounted to the manipulator. 
     The driving assembly  20  is attached to the first arm  13 . The driving assembly  20  includes an electrically-driven motor  21 , a driving wheel  23 , a follower wheel  25 , a conveyor belt  27 , and a shaft  29 . The motor  21  is secured to the first arm  13 . Two opposite ends of the conveyor belt  27  are respectively sleeved to the driving wheel  23  and the follower wheel  25 . The shaft  29  is rotatably mounted on the first arm  13 . The shaft  29 , the follower wheel  25 , and the rotating table  30  are coaxially mounted on the first arm  13 . The motor  21  drives the driving wheel  23  to make the follower wheel  25  rotate via the conveyor belt  27 , and then the rotating table  30  rotates along with the follower wheel  25 . In the exemplary embodiment, the motor  21  is a stepper motor. 
     Referring to  FIG. 4 , the rotating table  30  having a substantially cylindrical shape includes a sidewall  31  and two opposite end walls  32 . The plurality of suction assemblies  40  is equidistantly located on the sidewall  31  of the rotating table  30 . In the exemplary embodiment, the rotating table  30  is a regular polygon in cross-section. The sidewall  31  includes a plurality of fixing surfaces  311  with identical areas, which are successively connected to each other. Each suction assembly  40  is mounted on one of the plurality of fixing surfaces  311 . In the exemplary embodiment, the rotating table  30  has a regular pentagonal cross-sectional shape and includes five fixing surfaces  311 , and the suction device  100  includes five suction assemblies  40   a ,  40   b ,  40   c ,  40   d ,  40   e.    
     One end wall  32  of the rotating table  30  defines a fixing groove  33 . The opposite end wall  32  defines an engagement groove  35  (see  FIG. 1 ) and a protrusion  36  surrounding the engagement groove  35 . The sidewall  31  defines a plurality of through holes  37 . Each through hole  37  is located on one of the suction assemblies  40  and communicates with the fixing groove  33 . The through holes  37  extend towards inside of the fixing groove  33 . The inner ends of the plurality of through holes  37  all intersect at a single circle inside the rotating table  30 , that is to say, they are located in a same radial plane. 
     One end of the shaft  29  located apart from the first arm  13  is received in the engagement groove  35 . The protrusion  36  is attached to the follower wheel  25 . Thus, the rotating table  30 , the follower wheel  25 , and the shaft  29  are fixed together and rotate simultaneously. 
     Each suction assembly  40  includes a fixing block  41  and a suction cup  43 . The fixing block  41  attached to one of the fixing surface  311  defines a connecting hole (not shown) communicating with a through hole  37  of the fixing surface  311 . The suction cup  43  defines at least one suction port  431  communicating with the through hole  37  via the connecting hole. In the exemplary embodiment, the suction port  431  of one suction assembly  40  may differ in shape and/or structure from the suction port  431  of another suction assembly  40 , to facilitate the vacuum-lifting of different workpieces. 
     Referring to  FIG. 5 , the vacuum pump assembly  50  includes an airflow guiding part  51  and a connector  53 . The airflow guiding part  51  communicates with a vacuum generator (not shown) by the connector  53 , to generate a vacuum in the suction cup  43 . 
     The airflow guiding part  51  includes an adjoining element  511  and a guiding element  513  connected to the adjoining element  511 . The adjoining element  511  is mounted on the second arm  15  (see  FIG. 3 ). The guiding element  513  has a cylindrical shape, which fits into the circular fixing groove  33 . The guiding element  513  is not rotated by the fixing groove  33 . 
     The airflow guiding part  51  further defines a guiding hole  515 . The guiding hole  515  has one end communicating with the connector  53  and an opposite end opening on the periphery of the airflow guiding part  51 . In the exemplary embodiment, the guiding hole  515  is substantially L-shaped in section. One end of the guiding hole  515  extends through the end of adjoining element  511  mounted on the second arm  15 . The opposite end of the guiding hole  515  extends through a sidewall of the airflow guiding part  51  to define a gas evacuation hole  5151 . The connector  53  connects to the vacuum generator via a gas pipe (not shown). 
     In the exemplary embodiment, any gap between the sidewall of the guiding element  51  and the peripheral wall of the fixing groove  33  is less than 0.01 mm to prevent hermetic leakage, thus the workpiece is secure when being vacuum-lifted by the suction assembly  40 . The vacuum pump assembly  50  further includes two gaskets  55  to enhance the hermetic properties of the suction device  100 . In the exemplary embodiment, each gasket  55  is substantially O-shaped and made of elastic materials. The guiding element  513  further defines two fastening grooves  5131  spaced from each other, which are located on opposite sides of the gas evacuation hole  5151 . Each fastening groove  5131  is defined in and around the sidewall of the guiding element  513 . Each gasket  55  is latched within one of the fastening grooves  5131  and abuts against the peripheral wall of the fixing groove  33  to seal the gas evacuation hole  5151 . 
     Referring to  FIGS. 2-5 , in use, the driving assembly  20  drives the rotating table  30  to rotate one of the suction assemblies  40 , such as suction assembly  40   a , to a picking station. Thus, the suction cup  43  is aligned with a workpiece, and the through hole  37  is configured to be in communication with a suction cup  43  at this point. The vacuum generator is turned on, and the suction cup  43  vacuum-lifts the workpiece. The driving assembly  20  continues to rotate the rotating table  30  to make another suction assembly  40 , say suction assembly  40   b , move to the picking station. Thus, the suction cup  43  of the suction assembly  40   b  is aligned with another workpiece, and then the suction port  431  vacuum-lifts another workpiece. In this way, as the rotating table  30  is rotated, the suction ports  431  of suction assemblies&#39;  40   b - 4   e  can vacuum-lift workpieces in succession. 
     Since the suction device  100  includes a plurality of suction assemblies  40 , each suction assembly  40  is capable of picking one type of workpiece, therefore the suction device  100  can pick multiple and different workpieces, to avoid a plurality of manipulators being required. Thus, the suction device  100  reduces the cost of production and the volume of working space. 
     It is believed that the exemplary embodiment and its 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 advantages, the examples hereinbefore described merely being preferred or exemplary embodiment of the disclosure.