Abstract:
A valve assembly controls a vacuum. The valve assembly includes a poppet valve operatively connected to the vacuum. The poppet valve is movable between an open state and a closed state to turn the vacuum on and off respectively. A pilot valve is fixedly secured to the poppet valve to selectively move the poppet valve between its open and closed states. The valve assembly also includes a bladder system for controlling the pilot valve such that the pilot valve moves the poppet valve to the open position only when the bladder system measures a reduced suction force created by the vacuum to force the vacuum to increase the suction force produced thereby.

Description:
BACKGROUND ART 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates generally to a vacuum assembly. More particularly, the invention relates to a valve controlled vacuum assembly that reduces the consumption of energy in the operation thereto. 
         [0003]    2. Description of the Related Art 
         [0004]    Vacuums are useful devices in the manufacturing of items. Vacuums can be used to create a suction force that can be used to grab hold of a generally flat surface without damaging it. When a suction cup is used in conjunction with a vacuum, the suction cup can be secured to a desired part or item and moved or positioned more easily Oftentimes, the suction cups are affixed to the ends of robot arms to facilitate the robot and its ability to grab a hold of an item. 
         [0005]    In many situations, it is desirable to have the vacuum generating device as close to the suction cup as possible. In these situations, compressed air is used by the vacuum generating device to create the vacuum. One disadvantage of many of the system out there is the requirement for a constant source of compressed air for as long as the vacuum is need for the suction force. Use of the energy to supply the constant source of compressed air is costly. Therefore there is a desire for vacuum without the need for a constant source of compressed air. 
       SUMMARY OF THE INVENTION 
       [0006]    A valve assembly controls a compressed air operated vacuum circuit. The valve assembly includes a poppet valve operatively connected to the vacuum circuit. The poppet valve is movable between an open state and a closed state to turn the vacuum circuit on and off, respectively. A pilot valve is fixedly secured to the poppet valve to selectively move the poppet valve between its open and closed states. The valve assembly also includes a bladder system for controlling the pilot valve such that the pilot valve moves the poppet valve to the open position only when the bladder system measures a reduced suction force created by the vacuum to force the vacuum to increase the suction force produced thereby. 
         [0007]    Advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         [0008]      FIG. 1  is a perspective view of one embodiment of the invention; 
         [0009]      FIG. 2  is a top view of the invention; and 
         [0010]      FIG. 3  is an exploded perspective view of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0011]    Referring to  FIG. 1 , a valve assembly according to the invention is generally indicated at  10 , The valve assembly  10  is used to control a vacuum circuit, generally indicated at  12 . In one embodiment, the invention is a valve controlled vacuum assembly. 
         [0012]    The valve assembly  10  is used to create a vacuum, which in turn, operates a suction cup  14 . There are four suction cups  14  shown in  FIG. 1 . The suction cups  14  are secured to the valve assembly  10 . The valve assemblies  10  are secured to a robot arm  16  which is used for methods relating to manufacturing, packaging, and the like. In the embodiment shown in  FIG. 1 , the robot arm  16  is used in the process of manufacturing a door  18  of a motor vehicle not shown, It should be appreciated by those skilled in the art that the valve assembly  10  and the robot and  16  may be used in conjunction with the suction cup  14  to operate, lift, orient and/or move any type of item from an automotive door, as shown in  FIG. 1  at  18 , to something as small and fragile as an egg to be packaged in a carton for distribution and retail sale. 
         [0013]    A positioning mechanism generally indicated at  20 , is used to position the suction cups  14  with respect to the door  18  to be manipulated by the robot arm  16 . The positioning mechanism  20  may take any configuration necessary to allow the robot arm  16  the ability to adequately lift and manipulate the door  18 . In the embodiment shown, the positioning mechanism  20  includes a backbone structure  22  with a plurality of legs  24  extending out therefrom. A pneumatic line  26  runs along the robot arm  16  and through each of the legs  24  to provide compressed air to the valve assembly  10 . The valve assembly  10  and the vacuum circuit  12  operate on compressed air to operate the vacuum circuit  12  in such a manner to operate the suction cups  14 . The source of the compressed air is not shown and may be located remote from the robot arm  16 . The robot arm  16  is secured to a base  28  which may be fixed in position or may be movable as is required to perform the function for which the robot arm  16  is designed. 
         [0014]    Referring to  FIGS. 2 and 3 , the valve assembly  10  is shown in greater detail. The valve assembly  10  is secured to the robot arm  16  through an extension arm  30 . The extension arm  30  may secure the position and/or orientation of the suction cup  14  with respect to the robot arm  16 . The valve assembly  10  is secured to the extension arm using any number of mounts. Referring specifically to  FIG. 3 , an apple-core mounting pin  32  and a ball joint mounting pin  34  are shown as alternatives that may be used to secure the valve assembly  10  to the extension arm  30 . The choice of mounting pin would be dictated by the requirements of the valve assembly  10  and/or the suction cup  14 . It should be appreciated by those skilled in the art that other types of mounting pins may be utilized to facilitate the operation of the valve assembly. 
         [0015]    The suction cull  14  includes a threaded mounting m ember  36  that defines a pressure channel  38  coaxial with the threaded mounting member  36 . When a vacuum is drawn, discussed in greater detail subsequently, a vacuum is pulled through the pressure channel  38  allowing the suction cup  14  to create suction with the part, the door  18  in  FIG. 1 , to be affixed thereto. A suction cup collar  40  secures the suction cup  14  to the threaded mounting member  36 . 
         [0016]    The threaded Mounting member  36  threadingly engages a vacuum opening.  42  (shown in phantom) of a vacuum body  44 . The vacuum body  44  houses a vacuum generator  46 . The vacuum generator  46  is a compressed air operated vacuum generator  46  and is controlled by the compressed air extending through the pneumatic line  26 . In the embodiment shown, the compressed air operated vacuum generator is a coaxial cartridge that is held in the vacuum body  44  via a cartridge holder  48  that threadingly engages a vacuum channel  50  in the compressed air operated vacuum generator  46  is housed. A plug  52  seals the vacuum channel  48  at an end opposite the cartridge bolder  48 . Therefore, the cartridge holder  48 , compressed air operated vacuum generator  46  and the plug  52  are coaxial. 
         [0017]    The vacuum body also includes a blow off side that is regulated by a blow off valve  54  that includes a blow off spring  56 , a ball  58  disposed at the end of blow off spring  56  and a blow off plug  60  that maintains the ball  58  and blow off spring  56  in position. The blow off valve  54  operates with respect to the vacuum generator  46  in a known manner. 
         [0018]    Disposed adjacent the vacuum body  44  is a valve body  62 . The valve body  62  houses a poppet valve  64  therein. The poppet valve  64  includes a poppet valve trigger  66  The poppet valve trigger  66  extends into a pilot valve  68 . A pilot top mount  70  covers the pilot valve  68 . The pilot top mount  70  includes two side flanges  72 ,  74  that extend over the sides of the pilot valve  68 . The pilot top mount  70  has a pilot opening  76  disposed through the pilot top mount  70 . A diaphragm frame  78  is fixedly secured to the pilot top mount  70 . The diaphragm frame  78  includes a flexible diaphragm  80  that is in fluid communication with the pilot valve  68  because the majority of the flexible diaphragm  80  extends over the pilot opening  76  in the pilot top mount  70 . 
         [0019]    The flexible diaphragm  80  includes a diaphragm pin  82  molded thereto. The diaphragm pin  82  is used to position a hysteresis spring  84 . The hysteresis spring  84  is received by a valve cover  86 . The valve cover  86  includes a cover pin  88  which keeps the other end of the hysteresis spring  84  in position. The valve cover  86  is mounted to the diaphragm frame  78  and the pilot top mount  70 . 
         [0020]    In operation, compressed air flows through the pneumatic line  26  and enters the vacuum channel  50  of the vacuum body  44 . The flowing air passed the compressed air operated vacuum generator  46  creates a vacuum which, in turn, provides the force necessary for the suction cup  14  to create suction against a part, such as the door  18  shown in  FIG. 1 . Once the suction cup  14  obtains the proper suction force, the compressed air is turned off. 
         [0021]    As the suction cup  14  loses its suction, the hysteresis spring  84  forces the flexible diaphragm  80  downwardly into the pilot valve  68 . Once the pilot valve  68  moves a predetermined amount, it triggers the poppet valve  64  to open. Once the poppet valve  64  is open, the compressed air in the pneumatic line  26  is reopened and compressed air flows over the compressed air operated vacuum generator  46  to draw a vacuum and re-establish the suction force of the suction cup  14 . 
         [0022]    The poppet valve  64 , the pilot valve  68  aid the hysteresis spring  84  are all designed to allow the suction cup  14  to vary in suction force between 25 standard cubic feet per minute (SCFM) to 17 SCFFM. 
         [0023]    Without the invention, a continuous supply of compressed air must flow over the compressed air operated vacuum generator  46  to maintain the suction force created by the suction cup  14 . When it is determined that the suction cup  14  is to release the object  18  being held thereby, the compressed air is turned off allowing the vacuum to be exhausted land allowing thee suction cup  14  to release its suction force. 
         [0024]    With the valve assembly  10 , however, the suction cup  14  may maintain its suction force without having continuous compressed air flow through the pneumatic line  26 . As such, the consumption of compressed air is reduced to less than two percent of that which is manually required by a suction cup  14  when it is lifting an object  18  such as the door as depicted in  FIG. 1 . Therefore, the savings in energy consumption is great. 
         [0025]    The invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. 
         [0026]    Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.