Patent Abstract:
A gate valve with linkage structure includes at least a power cylinder, a valve body having a valve opening; a gate assembly in the valve body, having a main gate board and an air-tight gate board neighborly disposed, and connected with one end of the air-tight gate board by at least one parallel linkage; and at least a press bar, with one end pivotally connected to the air-tight gate board and the other end extending to form a press end. A linkage bar is pivotally connected to the press bar and also pivotally connected to the main gate board. Therefore, the gate assembly is driven to seal the valve opening; the air-tight gate board moves away from the main gate board with the linkage function; a sealing force is generated to keep the air-tightness between the air-tight gate board and the valve opening.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to seal structures of valve, and more particularly, to a vacuum valve driven by a linkage structure for sealing the air-tight valve board against the valve opening. 
     2. Description of the Related Art 
     In U.S. Pat. No. 7,134,642, a vacuum gate valve, as shown in  FIGS. 1 a , 1 b , and 1 c   , applies a control unit (such as a hydraulic and rotational unit), such that the valve stem is allowed to move freely along two directions, whereby the valve not only linearly moves along the valve stem axis (in parallel against the valve opening) for covering the valve opening, but also moves in vertical against the valve opening. Thus, when the valve board moves to the valve opening, the valve board is able to produce an addition sealing force upon the valve opening, so as to assure the air-tightness between the valve board and the valve opening. 
     However, such prior arts usually require a moving track controlling mechanism such as a slide rail disposed at the position of the hydraulic cylinder, wherein different sizes of valve boards and valve openings of vacuum valves with different models or sizes shall be calculated accurately and respectively, such that the valve board is allowed to move to the valve opening and firmly seal the valve opening. Otherwise, if the valve board is unable to cover the valve opening in parallel, the valve board possibly fails to appropriately seal the valve opening. As a result, the air-tightness of the vacuum valve is not achieved. Furthermore, after long period of being repeatedly used, wearing and accuracy deviation of the control unit may occur; in addition, the control unit is usually placed deep in the vacuum valve, causing the difficulty of maintenance. 
     SUMMARY OF THE INVENTION 
     For improving aforementioned issues, the present invention discloses a gate valve with linkage structure. When the gate assembly moves to be in alignment with the valve opening, the air-tight gate board of the gate assembly is allowed to vertically move toward the valve opening by use of the linkage, such that the air-tight gate board firmly covers the valve opening. 
     The present invention provides valve gate with linkage structure, comprising:
         at least a power cylinder, provided with a driving axle capable of axially moving;   a hollow valve body, with one end being an open end having a cover and the other end being a cylinder seat for receiving the power cylinder, an axle bore passing through the cylinder seat for the driving axle to penetrate into the valve body, wherein at least a valve opening is disposed on a lateral side of the valve body adjacent to the open end;   a gate assembly, disposed in the valve body and provided with a main gate board and an air-tight gate board neighboring on the main gate board, while the main gate board is connected to an end part of the air-tight gate board by use of at least a parallel linkage; and   at least a press bar, with one end pivotally connected to an end part of the air-tight gate board and the other end extending toward the cover to form a press end, wherein one end of a linkage bar is pivotally connected to the middle of the press bar, with the other end of the linkage bar pivotally connected to an end of the main gate board.       

     The main objective of the present invention is that the gate assembly is driven to move axially by the driving axle. When the gate assembly is in alignment with the valve opening, the press end of the press bar is pressed, and the air-tight gate board is moved away from the main gate board by the linkage effect produced by the press bar, the linkage bar, and the parallel linkage, whereby the air-tight gate board moves toward the valve opening to firmly seal the valve opening. 
     Another objective of the present invention is that the maintenance of the present invention is easy and time saving. During the maintenance, user needs only to open the cover and unscrew the screw members between the gate assembly and the driving axle, whereby the whole gate assembly is allowed to be taken out for repairing or replacing, thus greatly shorten the time cost for work suspension during the machine maintenance. 
     Still another objective of the present invention is that at least a stop member is disposed at the open end of the valve body. The stop member is in axial alignment with the press end of the press bar. When the gate assembly moves to be in alignment with the valve opening, the press end contacts the stop member, thereby driving the air-tight gate board to move while the stop member bears the counterforce of the pressing force. Therefore, the overall structural strength is enhanced; also, the maintenance of the stop member is easy. 
     Still another objective of the present invention is that at least a through groove is disposed on the main gate board. A roller bearing is pivotally disposed in the through groove, and the roller bearing partially protrudes on the lateral surface of the main gate board adjacent to the air-tight gate board. Furthermore, the air-tight gate board is concavely provided with a push groove for receiving the roller bearing. When the air-tight gate board is operated, the roller bearing works with the push groove, so as to disperse the counterforce born by the air-tight gate board, thereby preventing the air-tight gate board from being bent and deformed, also increasing the stability and service life of the product. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the gate valve with linkage structure in accordance with the present invention. 
         FIG. 2  is a partially exploded view of the gate valve with linkage structure in accordance with the present invention. 
         FIG. 3  is a second partially exploded view of the gate valve with linkage structure in accordance with the present invention. 
         FIG. 4  is a schematic view illustrating the installation process of the stop member provided by the present invention. 
         FIG. 5  is a partially sectional view of the gate valve with linkage structure in accordance with the present invention. 
         FIG. 6  is a partially sectional schematic view illustrating the operation process of the present invention. 
         FIG. 7  is a second partially sectional schematic view illustrating the operation process of the present invention. 
         FIG. 8  is a partially sectional schematic view illustrating the operation process of the roller bearing of the present invention. 
         FIG. 9  is a second partially sectional schematic view illustrating the operation process of the roller bearing of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The aforementioned and further advantages and features of the present invention will be understood by reference to the description of the preferred embodiment in conjunction with the accompanying drawings where the components are illustrated based on a proportion for explanation but not subject to the actual component proportion. 
     Referring to  FIG. 1  to  FIG. 5 , the present invention provides a gate valve with linkage structure, comprising at least a power cylinder  10 , a hollow valve body  20 , a gate assembly  30 , and at least a press bar  40 . 
     The power cylinder  10  is provided with a driving axle  11  capable of axially moving. 
     The hollow valve body  20  has one end thereof being an open end  21  provided with a cover  22 , and the other end thereof provided with a cylinder seat  23  for receiving the power cylinder  10 . An axle bore  24  passes through the cylinder seat  23  for the driving axle  11  to penetrate through and into the valve body  20 . Therein, at least a valve opening  25  is disposed on a lateral side of the valve body  20  adjacent to the open end  21 , and a hole  26  is disposed on the other lateral side of the valve body  20  opposite to the valve opening  25 . 
     The gate assembly  30  is disposed in the valve body  20  and provided with a main gate board  31  and an air-tight gate board  32  neighboring on the main gate board  31 . The main gate board  31  is screwed to an end of the driving axle  11  by use of a screw member  311 . Therein, the main gate board  31  is connected to an end part of the air-tight gate board  32  by use of at least a parallel linkage  33 . In a preferred embodiment, the main gate board  31  is connected with the air-tight gate board  32  by use of two parallel linkages  33  disposed between the two ends of the air-tight gate board  32 ; also, a four-linkage structure is formed among the main gate board  31 , the two parallel linkages  33 , and the airtight gate board  32 . In a more preferred embodiment, the four-linkage structure forms a parallelogram linkage structure. 
     At least a through groove  34  is disposed between the two ends of the main gate board  31 . A roller bearing  35  is pivotally disposed in the through groove  34  by use of an axle  351 , and the roller bearing  35  partially protrudes on the lateral surface of the main gate board  31  adjacent to the air-tight gate board  32 . Furthermore, the air-tight gate board  32  is concavely provided with a push groove  36  for receiving the roller bearing  35 . The push groove  36  has a first section  361  and a second section  362 , wherein the depth of the first section  361  is deeper than the depth of the second section  362  (as shown in  FIG. 3  and  FIG. 8 ), and the second section  362  is positioned at one end of the push groove  36  adjacent to the open end  21 . 
     One end of the press bar  40  is pivotally connected to an end part of the air-tight gate board  32 , while the other end of the press bar  40  extends toward the cover  22  to form a press end  41 . A bearing member  411  is disposed at the press end  41 . Therein, one end of a linkage bar  42  is pivotally connected to the middle of the press bar  40 , with the other end of the linkage bar  42  pivotally connected to an end of the main gate board  31 . Furthermore, as shown in  FIG. 3 , the linkage bar  42  extends from the pivot junction between the linkage bar  42  and the main gate board  31  toward the direction away from the air-tight gate board  32 , and the press bar  40  is in a shape similar to an L shape. In the preferred embodiment, the two ends of the gate assembly  30  are provided with a press bar  40 , respectively. 
     In addition, at least a stop member  50  is disposed at the open end  21  of the valve body  20 . Two inner walls of the open end  21  of the valve body  20  are provided with an arc recess  51  symmetrically disposed, respectively, for receiving the stop member  50 ; further, two ends of the stop member  50  are both an arc-shaped end. Therein, the length of the stop member  50  is larger than the width of the opening of the open end  21 . As shown in  FIG. 4 , the stop member  50  is obliquely placed into the open end  21  and subsequently rotated, so as to engage the two ends of the stop member  50  with the arc recess  51 . Furthermore, as shown in  FIG. 2 , the stop member  50  is convexly provided with an engage end  52  toward the cover  22 , and the inner side of the cover  22  is concavely provided with at least a position groove  53  for receiving the engage end  52 . Therefore, when the cover  22  is fixed to the open end  21 , as shown in  FIG. 5 , the position groove  53  is able to fix the position of the stop member  50 , so as to prevent the stop member  50  from departing from the arc recess  51 . 
     Therein, at least a spring member  37  is disposed between the main gate board  31  and the air-tight gate board  32 . As shown in  FIG. 3 , one end of the spring member  37  is connected to the axle  351  of the roller bearing  35 , while the other end is fastened to the air-tight gate board  32 , such that an elastic pulling force is produced for the air-tight gate board  32  to permanently lean against the main gate board  31 . In the preferred embodiment, the driving axle  11  is positioned at the center of the gate assembly  30 , while each side of the gate assembly  30  is provided with a roller bearing  35  and a push groove  36 , respectively, with two spring members  37  disposed on each of the axles  351 , respectively. 
     With the foregoing configuration, operation of the present invention will be illustrated below. 
     When the valve opening  25  opens, the gate assembly  30  is placed at one end of the valve body  20  in opposite to the open end  21 , and the air-tight gate board  32  leans against the main gate board  31 , as shown in  FIG. 5 . Meanwhile, the roller bearing  35  is placed in the deeper first section  361  of the push groove  36 . 
     When the valve opening  25  is to be closed, the driving axle  11  of the power cylinder  10  drives the gate assembly  30  to axially move in parallel to the valve opening  25  along the driving axle  11  toward the open end  21 , as shown in  FIG. 6 . When the gate assembly  30  is about to be in alignment with the valve opening  25 , the bearing member  411  of the press end  41  contacts the stop member  50 ; with the continuous operation of the driving axle  11 , the stop member  50  imposes a counter force upon the press end  41 , so as to press the press bar  40 . Therein, due to the pivot junction between the linkage bar  42  and the main gate board  31  being a fixed central axle, when the press end  41  of the press bar  40  bears a pressing force, the linkage bar  42  swings counterclockwise with the pivot junction A as the central axle, whereby the press bar  40  pushes the air-tight gate board  32  away from the main gate board  31 , so as to cause the air-tight gate board  32  to move toward the valve opening  25  until the air-tight gate board  32  firmly seal the valve opening  25 , as shown in  FIG. 7 . 
     At the same time, because the main gate board  31 , the two parallel linkages  33 , and the air-tight gate board  32  form a parallelogram linkage structure, when the press bar  40  pushes the air-tight gate board  32  to move, upper and lower ends of the air-tight gate board  32  are assured to move averagely, so as to make sure the air-tight gate board  32  leans against the valve opening  25  averagely. Thus, air-tightness is prevented from being weakened due to imbalance of the valve opening  25 . 
     Moreover, referring to  FIG. 8  and  FIG. 9 , when the air-tight gate board  32  is operated, the roller bearings  35  accordingly move to the second sections  362  of the push grooves  36 . Also, due to the depth of the second sections  362 , when the air-tight gate boards  32  move away from the main gate board  31 , the roller bearings  35  remain leaning against the air-tight gate board  32 . Therefore, when the gate valve with linkage structure of the present invention is in a larger size, multiple roller bearings  35  and corresponding push grooves  36  are allowed to be disposed thereon, so as to disperse the counterforce born by the air-tight gate board  32 , thereby preventing the air-tight gate board  32  from being bent and deformed, assuring the air-tightness between the air-tight gate board  32  and the valve opening  25 , and increasing the stability and the service life of the present invention. 
     On the other hand, when the valve opening  25  is to be reversely opened, the power cylinder  10  triggers the driving axle  11  and the gate assembly  30  to descend. With the bearing member  411  of the press end  41  gradually departing from the stop member  50 , the spring members  37  causes the air-tight gate board  32  and the main gate board  31  to be repositioned to lean against each other by use of the elastic pulling force, such that the air-tight gate board  32  departs from the valve opening  25 , whereby the valve opening  25  is opened. 
     In addition, the maintenance of the present invention is easy and time saving. During the maintenance, user needs only to open the cover  22  and unscrew the screw members  311  between the gate assembly  30  and the driving axle  11 , whereby the whole gate assembly  30  is allowed to be taken out for repairing or replacing process, thus greatly shorten the time cost for work suspension during the machine maintenance. 
     Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.

Technology Classification (CPC): 5