Abstract:
A closure device includes a door carrying a series of interconnected shear blocks and a keystone shear block designed to transfer stresses created by pressure acting on the door to a surrounding hub. Each interconnected shear block has a limited rotation relative to its adjacent blocks. A holding band operating handle is in communication with a driving link which, in turn, is in communication with the keystone shear block. Actuating the handle causes the keystone shear block to move in an upward vertical direction. The linear movement of the keystone shear block allows the limited rotation of the interconnected shear blocks to occur, thereby causing the circumferential holding band to collapse within itself from an expanded-engaged position to a contracted-removed position relative to said hub. A pressure warning lock provides a safety device and prevents actuation of the holding band operating handle when the pressure chamber is under pressure.

Description:
FIELD OF INVENTION 
       [0001]    The present invention relates to closures for sealing the end of a pressure chamber, such as a pipe or pipeline. More specifically, the invention is a new type of closure device to retain the closure door in a closed position and withhold the pressure from a pipeline. 
       BACKGROUND OF THE INVENTION 
       [0002]    Current pipeline closures use a varying range of means to withhold the pipeline pressure and retain the door closed, including simple threaded features, interlocking bayonet style connections, large clamps, and narrow flexible compression bands. For example, U.S. Pat. Nos. 7,051,897 and 7,341,161, issued May 30, 2006 and Mar. 11, 2008 to McGuire disclose a circumferential locking member having locking segments that are either carried by a thin carrier band or by partial carrier band segments. (McGuire also discloses interconnected locking segments.) A slot segment located between opposing ends of the locking member completes the 360° pressure bearing surface, and a linkage mechanism interconnects a lever with the opposing ends. Actuating the lever effectively pulls the two ends of the locking member together so that the locking member is in a radially retracted position. The slot segment, however, is removed in a completely separate and independent action from that of the lever. 
         [0003]    No current closure uses a single series of shear blocks to retain pipeline pressure, the shear blocks being linked together in such a way as to allow the entire assembly to retract and collapse within itself. Nor does any current closure place the holding band in communication with an operating lever such that actuating the lever results in automatic simultaneous actuation of a keystone shear block, thereby causing the holding band to expand or contract. 
       SUMMARY OF THE INVENTION 
       [0004]    A closure device according to this invention includes a hub having an access port and connected to a pressure chamber, such as a pipe or a pipeline. A door sized to close off the access port carries a circumferential holding band that is made up of a series of interconnected shear blocks and a keystone shear block. The interconnected shear blocks have a limited rotation relative to one another. A linear movement of the keystone shear block allows the limited rotation to occur, causing the circumferential holding band to collapse within itself from an expanded-engaged position to a contracted-removed position relative to said hub. 
         [0005]    When in the expanded-engaged position, a portion of the shear blocks and keystone shear block are retained by a circumferential groove in the hub. The shear blocks and the keystone shear block have a thickness “t” that is effective for transferring a stress created by a pressure acting on an inner face of the door to the hub when the holding band is in the expanded-engaged position. When in the contracted-removed position, the circumferential holding band is retained by a side wall located on the outer face of the door. 
         [0006]    The interconnected shear blocks are one of two types: a mid-band shear block and an end-band shear block. Each mid-band shear block has a first end and a second end and a pin connects the second end of one block to the first end of an adjacent block. The first and second ends may have a mating configuration, with one end receiving the opposing end of an adjacent block. Alternately, the ends may be flat surfaces and a plate link may be used for connecting adjacent blocks in combination with the pin. Similarly, the end-band blocks have a first and a second end, with the first end being mated or connected to the opposing end of an adjacent mid-band shear block. The second end of the end-band block is in communication with the keystone shear block. 
         [0007]    A holding band operating handle is in communication with a driving link which, in turn, is in communication with the keystone shear block. Actuating the handle causes the keystone shear block to move in an upward vertical direction. The linear movement and alignment of the keystone shear block is controlled in part by standoff pins that ride in a slot of a face plate connected to the door. 
         [0008]    The closure device also includes a pressure warning lock. The pressure warning lock is received by a portion of the holding band operating handle. In the engaged position, the pressure warning lock prevents movement of the holding band operating handle. 
         [0009]    A better understanding of the closure device will be obtained from the following detailed description of the preferred embodiments and claims, taken in conjunction with the attached drawings. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a front view of the two-piece closure device in its locked and engaged position within an access port of a hub connected to a pressure chamber. A series of interconnected shear blocks and a keystone shear block form a circumferential holding band that transfers the stresses created by chamber pressure acting upon the interior face of the closure door to the hub. 
           [0011]      FIG. 2  is a view of the closure device taken along section line  2 - 2  of  FIG. 1 . The circumferential holding band is received by a circumferential groove in the hub. The keystone shear block is connected to a holding band operating handle. 
           [0012]      FIG. 3  is a top view of the closure device in its locked and engaged position. A door handle and a pressure warning lock, which is received by the holding band operating handle, are provided. 
           [0013]      FIG. 4  is an isometric view of the closure device in its locked and engaged position. When engaged, the pressure warning lock prevents an operator from moving the holding band operating handle. 
           [0014]      FIG. 5  illustrates the closure device with the circumferential holding band in the locked and engaged closed position. 
           [0015]      FIG. 6  illustrates the closure device in the unlocked and engaged position. The pressure warning lock is disengaged and no longer preventing an operator from moving the holding band operating handle. 
           [0016]      FIG. 7  illustrates the closure device in the unlocked and disengaged position. Lifting the holding band operating handle causes the keystone shear block to move in a vertical direction which, in turn, causes the shear blocks to rotate. The limited rotation of the shear blocks then causes the holding band to collapse and retract within itself. Side walls capture and retain the collapsed holding band. 
           [0017]      FIG. 8  illustrates the closure device in the open position, providing access to an interior space of the pressure chamber. 
           [0018]      FIG. 9  illustrates an embodiment of the holding band in which the shear blocks are all linked one to another by pins. Actuating the holding band operating handle will retract all of the shear blocks from their engagement in the hub. 
           [0019]      FIG. 10  illustrates an alternate embodiment of the holding band in which the mid-band shear blocks and end-band shear blocks have flat ends and a recess for receiving a plate link and pins. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    Preferred embodiments of the two-piece closure will now be described with reference to the drawings and the elements illustrated in the drawings. The elements are identified by the following numbers: 
         [0000]    
       
         
               
               
             
           
               
                   
               
             
             
               
                 10 
                 Closure device 
               
               
                 12 
                 Access port 
               
               
                 18 
                 Circumferential edge 
               
               
                 20 
                 Hub 
               
               
                 22 
                 Hinge arm 
               
               
                 24 
                 Neck 
               
               
                 26 
                 Groove 
               
               
                 28 
                 Hinge arm 
               
               
                 30 
                 Door 
               
               
                 32 
                 Side wall 
               
               
                 34 
                 Hinge post 
               
               
                 36 
                 Face plate 
               
               
                 38 
                 Outer edge 
               
               
                 40 
                 Door opening handle 
               
               
                 44 
                 Threaded hole 
               
               
                 46 
                 Interior face 
               
               
                 48 
                 Exterior face 
               
               
                 50 
                 Pressure warning lock 
               
               
                 52 
                 Threaded shaft 
               
               
                 54 
                 Handle 
               
               
                 60 
                 Holding band 
               
               
                 62 
                 Pin 
               
               
                 63 
                 End 
               
               
                 64 
                 End 
               
               
                 65 
                 Recess 
               
               
                 66 
                 Mid-band shear block 
               
               
                 67 
                 End-band shear block 
               
               
                 68 
                 Holding band operating handle 
               
               
                 69 
                 Shear block plate link 
               
               
                 70 
                 Handle link 
               
               
                 72 
                 Pivot pin 
               
               
                 74 
                 Pivot pin 
               
               
                 76 
                 Holding band edge 
               
               
                 80 
                 Keystone shear block 
               
               
                 82 
                 Standoff pin 
               
               
                 84 
                 Driving link 
               
               
                 86 
                 Vertical slot 
               
               
                 88 
                 Standoff pin end 
               
               
                 90 
                 Side wall tab 
               
               
                 92 
                 Standoff pin 
               
               
                 94 
                 Arcuate-shaped slot 
               
               
                   
               
             
          
         
       
     
         [0021]    Referring to  FIGS. 1 to 4 , a two-piece closure device  10  provides a quick-acting closure to gain access to the interior of a pressure chamber such as a pipeline (not shown) when closure  10  is open, but withholds internal pressure when closure  10  is closed. Closure  10 , when in the closed and locked position, is capable of retaining pressure P in the chamber by transferring the stress caused by pressure P from the inside surface  46  of the door  30  back into the hub  20 . Hub  20 , which is welded onto the end of the chamber opening, is of a type well-known in the art and typically includes a reduced neck portion  24 . The pressure P on the entire inside surface  46  of the door  30  creates stresses in the door  30  which are transferred to the outer edge  38  of the door  30  though the door geometry. These stresses are then transferred into the circumferential holding band  60 . The stresses that are transferred into the holding band  60  are then transferred into the hub  20  because the edge  76  of the holding band  60  is captured in a groove  26  in the hub  20 . The geometry of groove  26  and the material around the groove  26  are designed in such a manner that the hub  20  is capable of withholding the stresses that will be transferred into it from a predetermined range of internal pressures P. 
         [0022]    The holding band  60  is the actual mechanism within the closure device  10  that converts from an expanded position—in which the holding band  60  is transferring stresses from the chamber pressure P into the hub  20 —to a contracted position, where holding band  60  will have retracted from the hub  20  and moved out of the way and allow the door  30  to be opened by an operator. Holding band  60  includes an interconnected series of mid-band shear blocks  66 , two end-band shear blocks  67  each linked to an adjacent mid-band shear block  66 , and a keystone shear block  80  in communication with the end-band shear blocks. Simple unlocking and opening movements will allow the door  30  to open and allow access to the contents of the chamber through access port  12 . 
         [0023]      FIGS. 5 to 8  illustrate closure device  10  as it passes from a locked and engaged position to an unlocked, disengaged open position. Closure device  10  is designed in such a way that the operator cannot open the door  30  without first unlocking the door  30 . The process of unlocking the door  30  includes removing a pressure warning lock  50  that includes a threaded shaft  52  and a handle  54 . See  FIG. 6 . Threaded shaft  52  is received by a threaded through-hole  44  within door  30 . See  FIG. 8 . Pressure warning lock  50  will warn the operator if there is any remnant pressure P within the chamber. In this manner closure device  10  warns the operator of a possible dangerous situation within the chamber before the door  30  is opened. When engaged, pressure warning lock  50  prevents the movement of holding band operating handle  68 , thereby ensuring that holding band  60  remains in an expanded-engaged position. See  FIG. 5 . 
         [0024]    Once the operator is reassured that the chamber is not pressurized and the door  30  is unlocked, the operator can then disengage the holding band  60  from the hub  20  by actuating the holding band operating handle  68 . See  FIG. 7 . Holding band operating handle  68  is pivotally connected to face plate  36  by pivot pin  72 , and a handle link  70  is pivotally connected to handle  68  by pivot pin  74 . Activating operating handle  68  will cause the holding band  60  to convert from an expanded-engaged position to a contracted-removed position. The door  30  would now be disengaged from the hub  20  and able to be opened through the door opening handle  40  See  FIG. 8 . 
         [0025]    Referring once again to  FIGS. 1 to 4 , circumferential holding band  60  is assembled out of a series of interconnected mid-band shear blocks  66 , two end-band shear blocks  67 , and a keystone shear block  80 . The shear blocks  66 ,  67 ,  80  transfer the pressure P of the chamber acting on the door  30  back into the hub  20 . The holding band  60  in the expanded position transfers the stresses created by the pressure P through shear loading through the solid thickness “t” of each individual shear block  66 ,  67 ,  80 . See  FIGS. 9 and 10 . The holding band  60  in the contracted position retracts from the groove  26  in the hub  20  to allow the door  30  to disengage from the hub  20  and be opened, thereby exposing access port  12 . See  FIG. 8 . 
         [0026]    Referring to  FIG. 9 , the shear blocks  66 ,  67  are all linked one to another by pins  62  so that the one motion of actuating the holding band operating handle  68  will retract all of the shear blocks  66 ,  67  from their engagement in the hub  20 . Each mid-band shear block  66  has a convex and concave arcuate-shaped end  64 A and  64 B, respectively. The ends  64  are formed so that end  64 A of one block  66  is received by end  64  of an adjacent block  66 . Similarly, each end-band shear blocks  67  has either a convex or a concave arcuate-shaped end  64 A or  64 B depending on whether an odd or even number of mid-band shear blocks  66  is used. An opposing end  63  of end-band shear block  67  is in communication with keystone shear block  80 . Each end  64  has a recess  65  for receiving the opposing, complementary end  64  of an adjacent shear block  66  or  67 . Each pair of adjacent mid-band shear blocks  66  are interconnected by a pin  62 . Pin  62  also connects end  64  of the end-band shear block  67  to the adjacent shear block  66 . 
         [0027]    The configuration of the interconnected shear blocks  66 ,  67  provides a limited range of rotation of each shear block  66 ,  67  relative to an adjacent shear block  66 . This rotation is what allows the entire holding band  60  to contract from an expanded-engaged position into the open-retracted position.  FIG. 10  illustrates an alternate embodiment of holding band  60  in which the mid-band shear blocks  66  and end-band shear blocks  67  have flat ends  64  and a recess  65  for receiving a of a plate link  69  and pins  62 . Again, each shear block  66 ,  67  has a limited range of rotation relative to an adjacent shear block  66 . 
         [0028]    Returning to  FIGS. 1 to 4 , the keystone shear block  80  is the final shear block of the holding band  60 . The keystone shear block  80  is restricted to a vertical movement and completes the engagement with the groove  26  in the hub  20  when holding band  60  is in the expanded-engaged position. The keystone shear block  80  is also used to drive all of the remaining linked shear blocks  66 ,  67  of the holding band  60 . The end-band shear blocks  67  place mid-band shear blocks  66  in communication with keystone shear block  80 . A downward, vertical movement of the keystone shear block  80  from a central location on the door  30  and toward the edge  38  of the door  30  causes the expanding motion within the holding band  60  through the driving link  84  and handle link  70 . Similarly an upward vertical movement in the keystone shear block  80  causes the holding band  60  to contract to a removed position. During the upward vertical movement of the driving link  84 , standoff pins  94 —which ride in arcuate-shaped slots  96  of face plate  36 —maintain the position of driving link  84  relative to the collapsing holding band  60 . 
         [0029]    In the closed-engaged position all of the holding band shear blocks  66 ,  67  and keystone shear block  80  are held captive in the groove  26  of the hub  20 . In the contracted-disengaged position the linked shear blocks  66 ,  67  are held against the exterior face  48  of the door  30  with tabs  90  protruding off of the side walls  32 . See  FIGS. 5 &amp; 6 . The side walls  32  limit the range of movement for the linked shear blocks  66 ,  67 , forcing a concentric contracted position of the holding band  60 . The side walls  32  also support the front plate  36  of closure device  10 . 
         [0030]    The keystone shear block  80  is held captive above the face  48  of the door  30  underneath the front plate  36  using standoff pins  82  to set the offset distance from the face  48  of the door  30 . These standoff pins  82  are also the means to restrict the keystone shear block  80  to solely a vertical movement, as the ends  88  of the standoff pins  82  ride in a vertical slot  86  in the front plate  36 . The front plate  36  extends past the circumferential edge  18  of hub  20  to provide a location for hinge post  34  to attach to front plate  36 . The hinge post  34  is provided as the axis for the hinge bearing  28  to rotate around. The hinge bearings  28  are held captive in hinge arms  22  that are welded to the hub  20 . 
         [0031]    While the preferred embodiments of closure device  10  have been described with a certain degree of particularity, the phraseology and terminology employed were for purposes of description and not limitation. Many changes may be made in the details of construction and the arrangement of components without departing from the spirit and scope of this disclosure. A closure device according to this invention, therefore, is limited only by the scope of the claims, including the full range of equivalency to which each element thereof is entitled.