Abstract:
A hinge mechanism for joining a door to a vessel is disclosed. The hinge mechanism includes a housing having a first end and a second end, and a rod reciprocally disposed in the housing, with the rod having a first end adapted to pivotally engage the door and further having a second end. A spring is disposed within the housing. A first coupling slidably connects a first end of the spring to the first end of the rod, and a second coupling slidably connects a second end of the spring to the second end of the rod. The spring, the housing, and the first and second couplings cooperate to permit movement of the rod between an outward position, an inward position, and a neutral position between the outward position and the inward position. The spring is arranged to bias the rod toward the neutral position.

Description:
RELATED APPLICATIONS  
       [0001]    This application claims priority from earlier filed U.S. provisional application Ser. No. 60/209,332, filed Jun. 2, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to pressure vessels. More specifically, the present invention relates to a double acting hinge for use on the door of a pressure vessel.  
         BACKGROUND OF THE INVENTION  
         [0003]    On a typical pressure vessel, such as, by way of example rather than limitation, an autoclave, the pressure vessel is provided with a door mounted on a pair of hinges. The opening to the vessel commonly requires a seal, with the seal being compressed between the door and the vessel when the door is closed and secured. Known closing mechanisms are usually employed which compress the door against the vessel, thus compressing the seal in order to provide an air tight fit. The seals are usually in the form of an  0 -ring which surrounds the opening to the vessel.  
           [0004]    A number of concerns exist in the prior art, including ensuring proper alignment of the hinges, providing for adequate compression of the seal, and protecting the seal from damage during opening and closing of the door. Thus, there exists a continuing need for improved pressure vessel components that address one or more of the afore-mentioned concerns. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIG. 1 is a top plan schematic view of a pressure vessel having a door mounted to the vessel by a hinge mechanism assembled in accordance with the teachings of the present invention;  
         [0006]    [0006]FIG. 2 is a partially exploded, fragmentary view in perspective of the pressure vessel and the hinge mechanism of FIG. 1;  
         [0007]    [0007]FIG. 3 is an enlarged cross-sectional view of the hinge mechanism assembled in accordance with the teachings of the present invention and illustrating the device in a neutral position;  
         [0008]    [0008]FIG. 4 is an enlarged cross-sectional view similar to FIG. 3 but illustrating the device in an inward position; and  
         [0009]    [0009]FIG. 5 is an enlarged cross-sectional view similar to FIGS. 3 and 4 but illustrating the device in an outward position; 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0010]    The embodiment described herein is not intended to be exhaustive or to limit the scope of the invention to the precise form or forms disclosed. Instead, the following embodiment has been chosen and described in order to best explain the principles of the invention and to enable others skilled in the art to follow its teachings.  
         [0011]    Referring now to FIGS. 1 and 2 of the drawings, a hinge mechanism assembled in accordance with the teachings of the present invention is generally referred to by the reference numeral  10 . The hinge mechanism  10  is shown mounted to a pressure vessel  12 , with the hinge mechanism  10  pivotally connecting a door  14  to the pressure vessel  12 . The pressure vessel  12  defines an interior cavity  16 , with one end of the pressure vessel  12  forming a peripheral rim  18  which is arranged to receive a seal  20 , such that an interface  22  between the door  14  and the rim  18  will form a pressure tight seal. The seal  20  will preferably take the form of an O-ring seal of the type commonly employed in the art. An axis  23  extends longitudinally through the pressure vessel  12 , with the axis  23  generally defining an inward direction  23 - 1  and an outward direction  23 - 2 . It will be understood that all references to the inward and outward directions are meant to be generally parallel to the axis  23  in either one of the inward direction  23 - 1  or the outward direction  23 - 2 .  
         [0012]    As shown in FIG. 1, one or more clamps  24  may be provided in order to secure the door  14  in the closed position of FIG. 1. Any number of commercially available clamps  24  may be employed, with the construction, function, and operation of such clamps  24  or other suitable closing mechanisms being generally well known to those of skill in the art.  
         [0013]    Referring now to FIGS.  3 - 5 , the hinge mechanism  10  is shown therein. Although the pressure vessel  10  will typically include a pair of such hinge mechanisms  10 , only a single such hinge mechanism  10  will be described in detail herein, it being understood that a second such hinge mechanism will be substantially identical. The disclosed hinge mechanism  10  includes a housing  26  having a pair of ends  28 ,  30 . In the disclosed embodiment, the housing  26  will be generally cylindrical, although other suitable shapes may be employed. An elongated rod  32  is disposed within the housing  26  such that the rod  32  will reciprocate as will be explained in greater detail below. The rod  32  includes a first end  34  and a second end  36 . The first end  34  of the rod  32  generally extends from the from the first end  28  of the housing  26 , while the second end  36  of the rod  32  generally extends from the second end  30  of the housing  26 . The first end  34  of the rod  32  includes a pivot  38 .  
         [0014]    In the disclosed embodiment the pivot  38  may take the form of a ball rod end  40  which is attached to the first end  34  of the rod  32 , such as by threads  40  (FIG. 3). Such a ball rod end  40  is commercially available from a wide variety of sources. Alternatively, the pivot  38  may be an integral part of the rod  32 . Still alternatively, the pivot  38  may take the form of any one of many commercially available pivot assemblies.  
         [0015]    A coil spring  42  is disposed within the housing  26 . The coil spring  42  includes a first end  44 , shown disposed toward the first end  28  of the housing  26  in FIG. 3, and a second end  46 , shown disposed toward the second end  30  of the housing  26  in FIG. 3. A first slidable coupling  48  and a second slidable coupling  50  are provided. The first and second slidable couplings  48 ,  50  slidably connect the spring  42  to the rod  32 , and enable the spring  42 , the rod  32 , and the housing  26  to interact in such a way that the rod  32  will be shiftable between the neutral position shown in FIG. 3, toward the inward position shown in FIG. 4 (i.e., with the rod  32  shifted toward the right when viewing FIG. 4), and the outward position shown in FIG. 5 (i.e., with the rod  32  shifted toward the left when viewing FIG. 5).  
         [0016]    The rod  32  includes a first shoulder  52  defined generally toward the first end  34  of the rod  32 , and further includes a second shoulder defined generally toward the second end  36  of the rod  32 . It will be noted that when the rod  32  is in the neutral position of FIG. 3, the spring  42 , by virtue of the slidable couplings  48 ,  50 , engages both of the first shoulder  52  and the second shoulder  54 . The first and second shoulders  52 ,  54  are separated by a central section  56  of the rod, with the central section  56  having a narrowed cross section  58  relative to a widened section  52 - 1  just beyond the first shoulder  52  and a widened section  54 - 1  just beyond the second shoulder  54 . The coil spring  42  defines a central passage  60  that extends lengthwise through the coil spring  42 . In the disclosed embodiment, the rod  32  extends through this central passage  60 .  
         [0017]    In the disclosed embodiment, the first and second slidable couplings  48 ,  50  each include a washer  62 ,  64 , respectively. Each washer  62 ,  64  includes a central aperture  62 - 1 ,  64 - 1 , respectively, sized to fit over the narrowed cross section  58  of the central section  56  of the rod  32 . Further, each of the washers  62 ,  64  is sized to abut an adjacent one of the shoulders  52 ,  54 . Accordingly, each of the washers  62 ,  64  will slide relative to the rod  32  along the central section  56 , with the travel of the washers  62 ,  64  being limited by contact with an adjacent one of the shoulders  52 ,  54  (i.e., travel of the first washer  62  is limited by contact with the first shoulder  52 , while travel of the second washer  64  is limited by contact with the second shoulder  54 ).  
         [0018]    The housing  26  includes a first bushing  66  located at the first end  28 , and a second bushing  68  located at the second end  30 . The bushings  66 ,  68  are sized to slidably receive the widened sections  52 - 1  and  54 - 1 , respectively, at the first end  34  and the second end  36  of the rod  32 . The bushing  66  includes an edge  70  disposed toward the spring  42 , while the bushing  68  also includes an edge  72  disposed toward the spring  42 . In the disclosed embodiment, the distance between the edges  70 ,  72 , matches the distance between the shoulders  52 ,  54 . Consequently, the rod  32 , when disposed in the neutral position of FIG. 3, will be maintained in the neutral position without having any “play” inwardly or outwardly (i.e., there will no movement of the rod  32  without the spring  42  being compressed).  
         [0019]    Preferably, the spring  42  is in under a pre-load at all times. That is, the spring  42  is already compressed when the rod  32  is in the neutral position, with the edge  70  applying a force toward the right when viewing FIGS.  3 - 5 , and the edge  72  applying a force toward the left when viewing FIGS.  3 - 5 . This pre-load on the spring  42  helps to maintain the rod  32  in the neutral position. The amount of the pre-load may be varied, depending on to what degree the user wishes to have the hinge mechanism biased toward the neutral position. This pre-load may be achieved by choosing a spring  42  having a relaxed or unloaded length that is longer than the distance between the first and second shoulders  52 ,  54 . Thus, when slidable couplings  48 ,  50  are assembled on the rod  32 , such as by threading the ball rod end  40  in place (the first shoulder  52  may be formed by a portion of the ball rod end  40 ), the spring  42  will be compressed between the shoulders  52 ,  54  as the shoulders are brought closer together by threading the ball rod end  40  onto the rod  32 .  
         [0020]    In operation, the door  14  is mounted to the pivot  38  on each of the provided hinge mechanisms  10 , such as by using a pin  74  (FIG. 2) through the ball rod end  40 . Instead of the pin  74 , any suitable rod, bolt, screw, or other structure may be employed. The pins  74  will secure two pairs of flanges  76 - 1 ,  76 - 2  (FIG. 2) to the ball rod end  40  at the first end  34  of the rod  32  on each of the hinge mechanisms  10 . The ball rod end  40  will serve to accommodate slight misalignment of the hinge mechanism  10  and/or slight misalignments of the flanges  76 - 1  and/or  76 - 2 . Consequently, smooth operation of the door  14  is facilitated. It will be understood that the hinge mechanisms  10  will be mounted directly to an outer portion  78  (FIGS. 1 and 2) of the pressure vessel  12 , such as by welding or bolting to any suitable mounting structure, flange, etc. (not shown), which may be formed on or attached to the outer portion  78  of the pressure vessel  12  in a known manner. It will also be noted that, when the pressure vessel  12  is being prepared for operation, the clamps  42  (or other suitable closing mechanism) will apply a generally inward force to the door  14  in order to compress the door  14  against the seal  20 , thus providing a more pressure-secure seal at the interface  22  between the door  14  and the peripheral rim  18 . This movement of the door  14  in the inward direction will cause the pin  74  to force the rod  32  in the inward direction (i.e., toward the right when viewing FIGS.  3 - 5 ).  
         [0021]    On the other hand, when the door  14  is opened (upon release fo the clamps  42  or other suitable closing mechanism, it may be desirable that the door  14  is able to be pulled away slightly from the peripheral rim  18 , such that the door  14  may be pivoted toward the open position (shown in dotted lines in FIG. 1) without binding on one edge of the seal  20 . In order to prevent binding, the door  14  (and specifically the flanges  76 - 1  and  76 - 2 ) may be displaced slightly in the outward direction away from the adjacent portion of the rim  18 . This outward movement of the door  14  will cause the pin  74  to force the rod  32  in the outward direction (i.e., toward the left when viewing FIGS.  3 - 5 ).  
         [0022]    Referring again to FIG. 3, when the rod  32  is disposed in the neutral position the spring  42  is preferably at least partially compressed in order to prevent play as outlined above, and in order to be under a pre-load. Thus, the first washer  62  is biased against the inner edge  70  of the first bushing  66 , and is also biased against the first shoulder  52 . Similarly, the second washer  64  is biased against the inner edge  72  of the second bushing  68 , and is also biased against the second shoulder  54 .  
         [0023]    When the door  14  of the pressure vessel  12  is closed and drawn inwardly by the clamps  42 , the rod  32  will shift inwardly by virtue of the inward force applied to the first end  34  by the pin  74 . Consequently, the rod  32  will shift toward the position of FIG. 4. When this happens, the second washer  64  (abutting the edge  72  of the bushing  68 ) moves along the central section  56  as the shoulder  54  and the widened section  54 - 1  slide through the bushing  68 . Thus, the hinge mechanism  10  accommodates inward movement of the door  14 . Also, by virtue of the washer  62  abutting the shoulder  52  and the washer  64  abutting the edge  72  of the bushing  68 , the spring  42  applies an outward biasing force to the rod  32 . This outward biasing force varies with distance as the rod moves, and may be calculated using well known engineering principles based on the spring constant for the chosen spring.  
         [0024]    On the other hand, when the door  14  of the pressure vessel  12  is to be opened, and it is desired to pull the door  14  away from the seal  20 , the rod  32  will shift outwardly by virtue of the outward force applied to the first end  34  by the pin  74  (passing through the neutral position of FIG. 3). Consequently, the rod  32  will shift toward the position of FIG. 5. When this happens, the first washer  612  (abutting the edge  70  of the bushing  66 ) moves along the central section  56  as the shoulder  52  and the widened section  52 - 1  slide through the bushing  66 . Thus, the hinge mechanism  10  accommodates outward movement of the door  14 . Also, by virtue of the washer  64  abutting the shoulder  54  and the washer  62  abutting the edge  70  of the bushing  66 , the spring  42  applies an inward biasing force to the rod  32 . Again, this outward biasing force varies with distance as the rod moves, and may be calculated using the well known engineering principles based on the spring constant for the chosen spring.  
         [0025]    According to the disclosed embodiment, the hinge mechanism provides a double action spring effect with a single spring  42 . The single, double acting spring permits the door  14  to be compressed onto the seal  20 , and further permits the door  14  to pull away from the seal  20  upon opening the door  14 , such that the seal  20  is not damaged by the door  14  as might occur with more convention hinges. Preferably, the spring is provided with a relatively high pre-load. Further, the ball rod ends  40  provide better alignment of the door  14  with respect to the hinges  10  and the vessel  12 .  
         [0026]    Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications which come within the scope of the appended claims is reserved.