Abstract:
A gasket and method of forming a seal between opposite surfaces of a pair of bodies. The gasket has a body with one portion having a plurality of perforations adapted for receipt between the opposite surfaces. The method of forming the seal includes disposing the portion of the body with the perforations between the opposite surfaces and fastening the pair of bodies to one another to compress the perforate portion of the body therebetween.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates generally to gaskets and their method of creating seals.  
         [0003]     2. Related Art  
         [0004]     Gaskets are commonly used to create a seal about passages extending between bodies attached to one another, such as in internal combustions engines, for example. It is known to form gaskets from a sheet or laminated sheets of imperforate gasket body material with a generally rigid core, and a more compliant material overlaying the core to create a resilient sealing surface for abutment with the bodies. The gaskets have openings formed through the imperforate body, wherein the openings conform with the passages, thereby providing an imperforate outer periphery for establishing a seal between the mating bodies and a completely unobstructed and open fluid flow path through the passages extending between the bodies.  
         [0005]     In an effort to reduce weight and cost, it is known to construct the core using a meshed wire material with a resilient outer sealing surface material applied over the meshed core to form a completely imperforate, solid body of gasket material. At some point, as mentioned above, openings are formed through the imperforate body, such as in a secondary operation, to provide an open path for fluid flow.  
       SUMMARY OF THE INVENTION  
       [0006]     A gasket for forming a seal about at least one passage extending into opposite surfaces of a pair of bodies attached to one another has a body with a layer of perforate webbing with a portion adapted for compression between the opposite surfaces. The webbing defines a plurality of perforations in the portion compressed between the bodies to facilitate establishing the seal between the opposite sides of the bodies.  
         [0007]     Another aspect of the invention provides a method of forming a seal between opposite surfaces of a pair of bodies having at least one fluid passage extending between the bodies. The method includes the steps of: providing a gasket body having a layer of perforate webbing; disposing the gasket body between the opposite surfaces with the perforate webbing being received between the opposite surfaces, and fastening the bodies to one another and compressing the perforate webbing of the gasket body between the opposite surfaces. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     These and other features and advantages of the present invention will become more readily appreciated when considered in connection with the following detailed description and appended drawings, wherein like features have been given like reference numerals, and wherein:  
         [0009]      FIG. 1  is an exploded partial perspective view of a gasket constructed according to one embodiment of the invention disposed between a pair of bodies to create a seal therebetween;  
         [0010]      FIG. 2  is an assembled cross-sectional view of the bodies with the gasket forming a seal therebetween;  
         [0011]      FIG. 3  is an enlarged partial cross-sectional view of the gasket of  FIG. 1 ;  
         [0012]      FIG. 4  is an enlarged partial cross-sectional view of a gasket constructed according to another presently preferred embodiment of the invention;  
         [0013]      FIG. 5  is an enlarged partial cross-sectional view of a gasket constructed according to yet another presently preferred embodiment of the invention;  
         [0014]      FIG. 6  is an enlarged partial perspective view of a gasket constructed according to yet another presently preferred embodiment of the invention;  
         [0015]      FIG. 7  is view similar to  FIG. 1  showing a gasket constructed according to another embodiment of the invention disposed between the pair of bodies to create a seal therebetween; and  
         [0016]      FIG. 8  is a view similar to  FIG. 2  showing the gasket of  FIG. 7  forming a seal between the bodies. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     Referring in more detail to the drawings,  FIGS. 1 and 2  show a gasket  10  constructed according to one presently preferred embodiment of the invention having a body  12  at least partially compressed between opposite surfaces  13 ,  15  of a pair of bodies  14 ,  16  to form an assembly, such as, by way of example and without limitations, a thermostat for an internal combustion engine. To body  12  has one portion adapted for compressed receipt between the opposite surfaces  13 ,  15 , and defines another region or portion adapted to allow fluid to flow generally unobstructed through at least one passage  18  extending into the opposite surfaces  13 ,  15  between the bodies  14 ,  16 . The portion compressed between the opposite surfaces  13 ,  15  comprises at least one layer of perforate webbed material or webbing  20  defining a plurality of perforations or voids  22  to facilitate establishing the seal between the opposite sides  13 ,  15  of the pair of bodies  14 ,  16 .  
         [0018]     The one or more layers of perforate webbing  20  can be formed separately from one another or together from one or more different types of material, either separately or in combination with one another, such as rubber or other polymeric materials, metallic materials, paper based materials, and various fibrous or ceramic materials, for example. Accordingly, the body  12  can be constructed via a multitude of manufacturing processes, either separately or in succession with one another, such as molding, weaving, stamping, blanking, and embossing, for example.  
         [0019]     The shapes and sizes of the plurality of voids  22  defined by the webbing  20  can be varied to best meet the application sealing requirements. For example, the voids can be circular, rectangular, triangular, oval, or polygonal, and can range from microns to millimeters in size. Preferably, the portion of the body  12  establishing the seal between the opposite sides  13 ,  15  is constructed having a uniform pattern of webbing, and thus, a uniform pattern of voids  22  having substantially the same size and shape across the body  12 . As such, the manufacturing efficiencies can be maximized, and the costs associated with the manufacturing process can be minimized. However, it should be recognized that the portion of the body  12  establishing the seal could be constructed having a non-uniform pattern of webbing  20 , and thus, the voids  22  could vary in size and/or shape across the body  12 , if better suited for the intended application.  
         [0020]     The voids  22  provide a more uniform compression of the webbing  20  by allowing the webbing  20  to be elastically and possibly plastically displaced laterally under load into the void area, thus facilitating the formation of a uniform seal between the opposite surfaces  13 ,  15 . Further, the voids  22  reduce the surface area of the gasket body  12  being compressed, and thus, the unit loading on the gasket body  12  is increased from that of known gaskets. Also, the voids  22  define redundant containment zones to prevent fluid from leaking past the entire gasket body  12  should any one of the webs defining an individual void  22  be damaged or broken. Accordingly, if one web is ruptured, adjacent voids defined by undamaged webs can still contain fluid from leaking, thereby inhibiting a leak past the gasket body  12 . This same aspect is particularly useful in establishing a reliable seal between surfaces that have some degree of damage, such as gouges or scratches, for example, or between surfaces having high porosity, such as commonly exists in surfaces of cast materials, for example. In addition, any fluid captured in the area of the voids  22 , such as may be incorporated during assembly by disposing a sealing fluid therein, or by having fluid enter therein during use, can also facilitate forming a reliable seal between the surfaces  13 ,  15 . The fluid within the voids  22  can act as a hydrostatic seal of sorts, thus, preventing the egress or ingress of fluid and/or contamination between the bodies  14 ,  16 .  
         [0021]     As mentioned, the gasket body  12  can be constructed utilizing various materials and patterns of webbing. For example,  FIG. 3  shows a body  12  constructed from two different materials, wherein the body  12  has a core  24  of a first material, for example, a layer of metallic wire screen mesh, and an outer layer  26  of a second material, for example, a layer of polymeric material, such as rubber. The polymeric outer layer  26  could be applied to the core  24  in various ways, such as molding or spray coating, for example, wherein the outer layer  26  is shown here as fully encapsulating the core  24 . In another example,  FIG. 4  shows a body  12  constructed form a single material, for example, a single layer of resilient polymeric material, such as rubber. The single layer is shown, by way of example and without limitations, as having webbing  20  that is generally circular in cross-section, though it should be recognized that the webbing  20  could be constructed having any suitable shape in cross-section. In yet another example,  FIG. 5  shows a body  12  constructed from at least two different materials, wherein the body  12  has a core  24  of a first material, for example, a generally rigid material, such as a generally flat layer of metallic material, and a pair of opposite second outer layers  26 ,  27  of material, for example, less rigid, more compressive and resilient layers of polymeric material. It should be recognized that the core  24  and outer layers  26 ,  27  could be formed from any suitable gasket material, and layered having any suitable number of layers with varying thicknesses, as desired. Further, the outer layers  26 ,  27  could be formed of different materials, such that one outer layer  26  could be formed from one resilient polymeric material, while the other outer layer  27  could be formed from a different resilient polymeric material, for example. Additionally, it should be recognized that the core  24  could be covered on a single side (not shown), such that in this example, one side would have the metal core  24  exposed, while the other side would have the more resilient layer exposed. In this example, the layers of material are shown having a rectangular or square shape in cross-section, wherein the outer layers  26 ,  27  do not fully encapsulate the core  24 , such that the core  24  is exposed within the voids  22 . In yet another example,  FIG. 6  shows a body  12  having a layer of metallic webbing  20  formed via an embossing process. As mentioned above, the webbing  20  could be arranged in other configurations than as shown, thereby defining voids  22  having the shape and size desired.  
         [0022]     As shown in  FIG. 1 , the gasket  10  can have a plurality of openings  30  formed therein to facilitate receipt of fasteners  32  used to attach the bodies  14 ,  16  to one another. However, it should be recognized that though the openings  30  may be desirable in some applications, the formation of openings  30  may not be necessary. This results from the ability of the fasteners  32  to readily form openings through the gasket body  12  by pushing the fasteners  32  therethrough. This is facilitated by the plurality of voids  22  in the gasket body  12 , wherein the force applied to the fasteners  32  can readily form an opening through the webbing  20  without causing damage to the gasket body  12 . Accordingly, the gasket body  12  can be constructed without the openings  32  formed therein, thereby reducing the overall cost to manufacture the gasket  10 , if desired.  
         [0023]     As shown in  FIGS. 1 and 2 , gasket body  12  has a region or portion defining an opening  34  radially inwardly from the one portion of webbing  20  corresponding with the passage  18 . The opening  34  is shown as being shaped to conform with the passage  18 , and thus, the webbing  20  generally does not extend into the passage  18 . As such, fluid is allowed to flow completely unobstructed through the passage  18 . It should be recognized that the number and shape of the openings formed in the gasket body  12  can be varied to correspond with the number and shape of the passages extending between the bodies  13 ,  15 .  
         [0024]     As shown in  FIGS. 7 and 8 , a gasket  10  constructed according to another embodiment of the invention has one portion, represented here as an outer periphery, for example, at least partially compressed between the opposite surfaces  13 ,  15 , and another portion adapted to traverse at least partially, and represented here as extending completely across the fluid passage  18 . It should be recognized that this embodiment is only useful in applications not having mechanical apparatus, such as pistons, for example, traversing the passage  18 . Preferably, the two portions of the gasket  10  are constructed from the same webbed material with voids  22  of uniform shape and size. The voids  22  in the portion traversing the passage  18  are sized to allow fluid to flow generally unobstructed through the passage  18 . Accordingly, the gasket  10  does not require a separate opening conforming to the size of the passage  18  to be formed therein. As such, the gasket  10  can be used universally across a variety of applications having one or more passages, regardless of the sizes and shapes of the passages. In addition, the gasket  10  manufacturing efficiencies are maximized as a result of not having to form separate openings.  
         [0025]     If an application requires a specific fluid flow rate through the passage  18  and a specific compression of the portion of the gasket body  12  compressed between the bodies  14 ,  16 , the voids  22  traversing the passage  18  could be sized differently than the voids  18  compressed between the mating surfaces  13 ,  15 . As such, the outer periphery of the gasket body  12  could be constructed have one pattern of webbing to provide the seal integrity needed, while the portion of the body  12  extending across the passage  18  could have a different pattern of webbing to provide the size and shape of voids  22  best suited to achieve the desired fluid flow rate. Otherwise, the gasket  10  can be constructed the same as described of above in the previous embodiments.  
         [0026]     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.