Abstract:
A vacuum-powered film-applying mechanism for applying a flexible film to a workpiece includes a bracket, a suction member, and a rotating joint. The suction member is rotatably mounted on the bracket, and defines a peripheral surface and a plurality of suction chambers therein, and by virtue of a vacuum created in the interior of the suction member, a length of flexible film is attracted and adhered. The rotating joint on the bracket communicates with the plurality of the suction chamber, through the rotating joint, air is supplied and exhausted from the plurality of suction chambers progressively, on a one by one basis, to pick up and roll the flexible film onto itself, and by supplying air to the plurality of suction chambers one by one, unrolls and releases the flexible film onto the workpiece with a low incidence of trapping air bubbles.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a mechanism which apply labels or other materials to products, and more particularly, to a mechanism for sticking or adhering a film made of flexible materials to a workpiece. 
     2. Description of Related Art 
     In industry, a mechanism is employed to pick up a film made of flexible materials in strip shape, such as an adhesive tape, and to paste or adhere the flexible film to a workpiece. The mechanism includes a moving assembly and a pick-up member connected to the moving assembly. The pick-up member is in a plate shape with a negative pressure therein. When picking up the flexible film, the moving assembly moves the pick-up member to the flexible film, the pick-up member presses against the flexible film and picks it up. Then the moving assembly moves the pick-up member to the workpiece, the pick-up member releases the flexible film onto the workpiece and pastes or adheres the flexible film onto the workpiece entirely. However, air bubbles are often generated between the flexible film and the workpiece. 
     Therefore, there is room for improvement in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead 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 isometric view of an embodiment of a film-applying mechanism. 
         FIG. 2  is an exploded, isometric view of the film-applying mechanism of  FIG. 1 . 
         FIG. 3  is similar to  FIG. 2 , but viewed from another aspect. 
         FIG. 4  is a cross-sectional view of the film-applying mechanism of  FIG. 1 , taken along line IV-IV of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an embodiment of a vacuum-powered film-applying mechanism  100  includes a bracket  10 , a suction member  20 , a rotating joint  30 , and an adjusting assembly  40 . The suction member  20  is rotatably mounted on the bracket  10 . The rotating joint  30  is rotatably mounted on the bracket  10  adjacent to the suction member  20 . The rotating joint  30  is connected to the suction member  20  for supplying and extracting air from the suction member  20 . The adjusting assembly  40  is mounted on the bracket  10  and resists the suction member  20  to provide a rotational resistance force against the suction member  20 . 
     Also referring to  FIGS. 2 and 3 , the bracket  10  includes a mounting plate  11 , a pair of supporting plates  13 , and a rotating shaft  15 . The mounting plate  11  is mounted on a robot arm (not shown). The pair of supporting plates  13  extends from opposite ends of the mounting plate  11  perpendicularly. The mounting plate  11  and the pair of supporting plates  13  cooperatively form a “U” shape. The rotating shaft  15  is rotatably mounted on the pair of supporting plates  13 , and spaced from the mounting plate  11 . Opposite ends of the rotating shaft  15  are secured by the pair of supporting plates  13 . Each supporting plate  13  defines a pair of screw holes  131  adjacent to opposite sides of the rotating shaft  15 . 
     Also referring to  FIG. 4 , the suction member  20  is cylindrical, and includes a main body  21 , a shielding cover  23  mounted on an end of the main body  21 , and a mounting subassembly  25 . The main body  21  is annular, and defines a pair of receiving holes  211  at opposite ends thereof and a sleeving hole  213  interconnecting the pair of receiving holes  211 . The sleeving hole  213  is located between the pair of receiving holes  211  and communicates with the pair of receiving holes  211  at opposite ends thereof. The sleeving hole  213  has a diameter smaller than that of each of the receiving holes  211 . The main body  21  is rotatably sleeved on the rotating shaft  15  through the sleeving hole  213 . The main body  21  defines a peripheral suction surface  218  along an outer periphery thereof, and a plurality of suction chambers  215  surrounding a center of the main body  21 , and the main body  21  also includes a plurality of separating portions  216 . The peripheral suction surface  218  defines a plurality of suction holes  2181  divided into several groups. Each group of suction holes  2181  communicates with one of the suction chambers  215  and is open to the outside air. The plurality of suction chambers  215  are defined at an end of the main body  21  and uniformly arranged adjacent to a periphery of the main body  21  in a looped configuration. Each separating portion  216  is formed between two adjacent suction chambers  215  to separate the two adjacent suction chambers  215 . Each separating portion  216  defines a fixing hole  2161  therein along an axial direction of the main body  21 . 
     The shielding cover  23  is assembled to the end of the main body  21  of which the plurality of suction chambers  215  is defined, thereby sealing the plurality of suction chambers  215 . The shielding cover  23  includes an annular base body  231  and a plurality of sealing portions  233  formed on the base body  231 . The plurality of sealing portions  233  are uniformly arranged adjacent to a periphery of the base body  231  in a looped configuration for sealing each of the plurality of suction chambers  215 . Each sealing portion  233  defines a though hole  2331  cutting through the base body  231 , the through holes  2331  communicate with the suction chamber  215  for supplying and exhausting air from the suction chamber  215 . The base body  231  defines a plurality of mounting holes  2311  thereon, and each mounting hole  2311  is located between two adjacent sealing portions  233 . The base body  231  is mounted on the main body  21  via the plurality of mounting holes  2311  and the plurality of fixing holes  2161 . 
     The mounting subassembly  25  includes a pair of bearings  251  and a fixing member  253 . The pair of bearings  251  is rotatably sleeved on the rotating shaft  15 , and received in the pair of receiving holes  211 . The pair of bearings  251  rotatably interconnects the main body  21  and the rotating shaft  15 . The fixing member  253  is sleeved on the rotating shaft  15  adjacent to the end of the main body  21  where the shielding cover  23  is located. The fixing member  253  resists one of the bearings  251  toward the sleeving hole  213  to hold the suction member  20 . 
     The rotating joint  30  is rotatably sleeved on the rotating shaft  15  adjacent to the shielding cover  23 . The rotating joint  30  defines a first air conduit  31  and a plurality of second air conduits  33 . The first air conduit  31  is connected to pressured vacuum source (such as vacuum pump, not shown), and the plurality of second air conduits  33  communicates with the first air conduit  31 . The plurality of second air conduits  33  further communicate with the plurality of though holes  2331  of the shielding cover  23  via pipes or tubes (not shown). When a diameter of the rotating joint  30  is equal to that of the shielding cover  23 , and the plurality of second air conduits  33  connects directly with the plurality of though holes  2331 , the pipes or tubes may be omitted. 
     The adjusting assembly  40  is mounted on an end of the main body  21  opposite to or away from the shielding cover  23 . The adjusting assembly  40  includes a first friction member  41 , a second friction member  43 , and a pair of resisting members  45 . The first friction member  41  and the second friction member  43  are located between the main body  21  and one supporting plate  13 . The first friction member  41  and the second friction member  43  are bowl-shaped, and each thereof defines an opening (not labeled) toward the main body  21 . The first friction member  41  defines a pair of resisting holes  411  thereon communicating with the opening thereof. The second friction member  43  has a diameter smaller than that of the first friction member  41 , and is partially received in the first friction member  41 . The second friction member  43  is made of rubber, and resists the main body  21  toward the fixing member  253 . Each resisting member  45  engages with one screw hole  131 , extends through one resisting hole  411 , and then resists against the second friction member  43 . The resisting member  45  includes a head portion  451  and a resisting portion  453  coaxial to the head portion  451 . The head portion  451  protrudes out from the supporting plate  13 , and the resisting portion  453  resists the second friction member  43  toward the main body  21 . 
     When assembling, the shielding cover  23  is assembled to the main body  21  to seal the plurality of suction chambers  215  by means of the plurality of sealing portions  233 . The suction member  20  is rotatably sleeved on the rotating shaft  15  via the mounting subassembly  25 . The adjusting assembly  40  and the rotating joint  30  are assembled to opposite ends of the suction member  20 . The rotating shaft  15  is assembled to the pair of supporting plates  13 , and the mounting plate  11  is assembled to the robot arm. 
     When in use, the suction member  20  attracts an end of a flexible film (not shown), the flexible film will adhere tightly to the peripheral suction surface  218 . The suction member  20  rotates to travel along the flexible film, and simultaneously, negative air pressure is generated progressively in the suction chambers  215  on a one by one basis via the rotating joint  30 , so that the suction member  20  thus rolls up the flexible film and carries the length of the flexible film adhering to the peripheral suction surface  218 . The flexible film is finally wound around the suction member  20 . The vacuum powered film-applying mechanism  100  is moved to a workpiece (not shown), and the suction member  20  places and presses the flexible film on the workspace, and rolls along the workpiece. Positive air pressure is generated in the suction chambers  215 , thereby releasing and pressing the flexible film onto the workpiece, and the flexible film thus adheres to the workpiece. Rotating the pair of resisting member  45  to resist the first friction member  41 , and the friction member  41  may move toward the main body  21 , thereby adjusting the resist force on the suction member  20 . 
     In the film-applying process, the suction member  20  unrolls and adheres the flexible film onto the workpiece by rotating and pressing the flexible film on the workpiece, and the plurality of suction chambers  215  releases one by one each of their suction on the flexible film, therefore, the likelihood of air bubbles trapped between the flexible film and the suction member  20  is reduced, and a quality of the film-applying process is enhanced. When rotating the pair or resisting member  45  to resists the first friction member  41 , a rotating resistance force of the suction member  20  is thereby adjusted; therefore it is adapted to fully stretch the flexible film to be as far as it can be stretched. 
     The plurality of suction chambers  215  may be substituted by an integrally annular chamber. The groups of suction holes  2181  communicate with the integrally annular chamber. The groups of suction holes  2181  may be uniformly distributed along the peripheral suction surface  218  of the suction member  20 . 
     The first friction member  41  may be made of rubber without having any resisting holes  411 , and the resisting member  45  may then be directly resisting the first friction member  41 . The resisting holes  411  may be screw holes, and the resist member  45  may engage with the resisting holes  411 . 
     Finally, while various embodiments have been described and illustrated, the disclosure is not to be construed as being limited thereto. Various modifications can be made to the embodiments by those skilled in the art without departing from the true spirit and scope of the disclosure as defined by the appended claims.