Abstract:
A gasket is provided including a screen. An elastomeric material coats the screen. In one embodiment, the elastomeric material provides sealing ribs to provide a tight seal.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to gaskets, and more particularly, to an elastomer coated screen gasket.  
       BACKGROUND OF THE INVENTION  
       [0002]     Gaskets have been used for many years for providing a sealed connection between two relatively static members. Gaskets typically require a compressive load between the members being sealed in order for the gasket to provide an effective seal. For example, a gasket placed between two stationary members, such as an engine block and an oil pan or an engine cylinder head and a valve/cam cover, is compressed between these elements.  
         [0003]     One gasket design has a solid metal core which may or may not be coated or partially coated with a polymeric material. The use of a solid metal core increases the cost of the gasket and requires a greater thickness due to the stamping operation used to manufacture the metal core. Furthermore, any desired change in shape of the gasket requires new stamping plates, making minor design changes cost prohibitive. In addition, the polymeric material coating the gasket may be hard to process requiring longer manufacturing times and further increasing the cost of the gasket.  
         [0004]     Accordingly, a need exists for a gasket having reduced cost and greater design flexibility.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention provides a gasket including a wire screen. An elastomeric material coats the wire screen. The use of a wire screen reduces the cost of the gasket while improving durability and design flexibility.  
         [0006]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0008]      FIG. 1  is a perspective view of an elastomer coated screen gasket according to the principles of the present invention;  
         [0009]      FIG. 2  is a schematic view of a wire screen used in the gasket of the present invention;  
         [0010]      FIG. 3  is a cross sectional view taken along line  3 - 3  of  FIG. 1 ; and  
         [0011]      FIG. 4  is a magnified view of detail  3  in  FIG. 3 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0012]     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0013]     Referring now to  FIG. 1 , a gasket  10  according to the principles of the present invention is shown. It will be understood that the shape and dimensions of the gasket  10  enclosed herein are for illustrative purposes only and do not limit the scope of the present application. The gasket  10  includes a screen  12  embedded in an elastomeric material  14 .  
         [0014]     The screen  12  (as illustrated in  FIG. 2 ) includes several openings  16  between the cross weaved wires  17  which facilitate the flow of the elastomeric material  14  therethrough while the gasket  10  is being molded. The screen  12  may be comprised of aluminum, copper, steel, carbon fiber, perforated sheeting, such as MYLAR, or any other suitable material and may be pre-cut into a desired shape prior to the introduction of the elastomeric material  14  or may be in sheet form and cut later. The screen  12  has a thickness T which according to a first embodiment may be approximately 0.2 millimeters (mm) to 0.3 millimeters (mm). The thickness T is generally uniform. A central aperture  18  may be formed along a centerline C prior to the introduction of the elastomeric material  14 .  
         [0015]     With reference now to  FIG. 2 , a first end  20  of the screen  12  may further include a first aperture  22  for receipt of a first coupling mechanism (not shown), such as, for example, a bolt or screw, therethrough. The screen  12  has a second end  24  which may include a second aperture  26  for receipt of a second coupling mechanism (not shown). The screen  12  has a top side  28  and a bottom side  30  which is coated with the elastomeric material  14 .  
         [0016]     With continuing reference to  FIG. 2  and additional reference to  FIGS. 1, 3  and  4 , the elastomeric material  14  may coat the top side  28  and bottom side  30  of the screen  12  such that the screen  12  is completely embedded by the elastomeric material  14 , forming the gasket top side  28 ′ and the gasket bottom side  30 ′, each having a first end  20 ′ and a second end  24 ′. The central aperture  18  of the screen  12  may be coated or remain uncoated by the elastomeric material  14 .  
         [0017]     Both the top side  28 ′ and the bottom side  30 ′ may include a plurality of sealing ribs  36 ,  40 ,  42 . The plurality of sealing ribs  36 ,  40 ,  42  may be formed from elastomeric material  14  and may surround the central aperture  18  of the screen  12 . More specifically, an area  34  having a first predetermined thickness may be formed directly adjacent to the central aperture  18 . The area  34  is adjacent a first sealing rib  36 . The first sealing rib  36  is adjacent a valley  38 . The valley  38  is further adjacent to a second sealing rib  40 . The second sealing rib  40  is separated from a third sealing rib  42  by a second valley  44 . The first sealing rib  36  has a height H 1  which is generally greater than a height H 2  of the second sealing rib  40 . The third sealing rib  42  also has a height H 3  which is generally smaller than the height H 2  of the second sealing rib  40 . The valleys  38  and  44  are configured such that when a downward force F is applied to the first, second and third sealing ribs  36 ,  40  and  42 , the first, second and third sealing ribs  36 ,  40  and  42  can deform into the valleys  38  and  44 . The first, second and third sealing ribs  36 ,  40 ,  42  ensure a tight seal.  
         [0018]     The first end  20 ′ of gasket  10  may include a first mounting aperture  46  which corresponds to the first aperture  22  of the screen  12  for receipt of the first coupling mechanism therethrough. The first mounting aperture  46  may be configured to extend beyond the first aperture  22  of the screen  12  to provide a first elastomeric buffer region  48 . Similarly, the second end  24 ′ of gasket  10  may include a second mounting aperture  50  corresponding to the second aperture  26  of the screen  12  for receipt of the second coupling mechanism therethrough. The second mounting aperture  50  may also extend beyond the second aperture  26  of the screen  12  to form a second elastomeric buffer region  52 . The first and second elastomeric buffer regions  48 ,  52  ensure a tight seal against the first and second coupling mechanism. It should be understood that the screen  12  may be completely coated with the elastomeric material prior to a cutting process during which the apertures in the screen are formed.  
         [0019]     A first raised portion or shelf  54  may be formed adjacent to the first mounting aperture  46  on both the top side  28 ′ and bottom side  30 ′ of gasket  10 . A second raised portion or shelf  56  may also be formed on both the top side  28 ′ and bottom side  30 ′ adjacent to the second mounting aperture  50 . The first raised portion  54  and second raised portion  56  provide a support to prevent the flexing of a part (not shown) which mates with the gasket  10  and thus further ensures a tight seal.  
         [0020]     The elastomeric material  14  may comprise nitrile rubber (NBR) with a low acrylonitrile (ACN) content, medium ACN content NBR, high ACN content NBR, butyl-chlorobutyl, chloroprene, chlorosulfonated polyethylene, ethylene propylene, epichlorohydrin, ethylene vinyl acetate, floursilicone, fluorocarbon, hydrogenated NBR, polyisoprene, polyuacrylate, propylene oxide, polybutadiene, polysulfide, modified NBR, silicone, styrene butadiene rubber (SBR) or any enhanced performance polymer or thermoplastic elastomer.  
         [0021]     To form the gasket  10  of the present invention, the screen  12  is placed into a mold cavity (not shown). The screen  12  may be of a pre-determined shape or may be in sheet form. Next, the elastomeric material  14  is injected into the mold cavity. The elastomeric material  14  then flows through the openings  16  in the screen  12  to substantially coat the top and bottom of the screen  12 , forming the top side  28 ′ and the bottom side  30 ′ of the gasket  10 . In this embodiment, the mold cavity is such that the elastomeric material  14  flows around the central aperture  18 , however, it is envisioned that the central aperture  18  could be created in a later processing step. Likewise, the mold cavity may also be configured to enable the elastomeric material  14  to flow and create the first and second mounting apertures  46 ,  50  or the first and second mounting apertures  46 ,  50  may be created in a later processing step. In addition, the mold cavity may be configured to allow excess elastomeric material  14  to form the first, second and third sealing ribs  36 ,  40 ,  42 . In addition, the mold cavity could be designed such that excess elastomeric material  14  may form the first raised portion  54  and the second raised portion  56  adjacent the first and second mounting apertures  46 ,  50 .  
         [0022]     The gasket  10  of the present invention reduces the weight and cost of current gaskets through the use of a screen  12 . The screen  12  provides the gasket  10  with a compression limiting feature while enabling the gasket  10  to have a reduced thickness. The screen  12  also enables the shape of the gasket  10  to be easily modified to suit any desired design change. The use of the screen  12  also reduces the amount of torque required to create a sufficient seal. In addition, the elastomeric material  14  coating the screen  12  is generally more durable, resistant and easier to process than current elastomeric materials used in gaskets.  
         [0023]     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.