Abstract:
A weather strip for use on a vehicle comprises an engaging portion for securing a weather strip to a vehicle and a weather strip body comprising a compressible portion and a magnetic sealing portion. The magnetic sealing portion provides a seal acting in a direction projecting toward a magnetically attractive substrate to provide a sealing interference between the magnetic sealing portion and the substrate when the weather strip is installed on the vehicle and a door closes the opening. The weather strips described herein provide an air and water tight seal without requiring a high compression force, thus improving door operation and reducing closing noise by eliminating the need to slam the door.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to weather stripping for motor vehicles and more particularly to weather stripping having a magnetic sealing surface. 
     BACKGROUND OF THE INVENTION 
     Numerous types of weather stripping have been provided in the prior art that are adapted to seal spaces between objects. Weather stripping on automobiles needs to be tightly compressed to eliminate leakage, e.g., due to rain or washing, and to minimize noise due to air entering the vehicle through small gaps. To obtain a sufficient degree of compression, a high degree of force is generally needed to close the automobile door. This results in a high slamming force for closing as well as a high force for opening due to friction on the latching system. It would therefore be desirable to provide improved weather stripping to improve the ergonomics of vehicle door operation by reducing the force needed for opening and closing vehicle doors. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a weather strip that provides a sealing engagement between an opening in a vehicle and a vehicle door, or other closing member, and that reduces the force needed for opening and closing the door. By reducing the force needed to close the door, the need to slam the door is eliminated and closing noise is reduced. 
     The present invention provides a weather strip for use on a vehicle comprising an engaging portion for engaging a portion of the vehicle defined peripherally about an opening provided on the vehicle and a weather strip body comprising a compressible portion and a magnetic sealing portion. The magnetic sealing portion provides a seal acting in a direction projecting toward a member operatively attached to the vehicle for closing the opening, wherein the magnetic sealing portion and the closing member are magnetically attractive so as to provide a sealing interference between the magnetic sealing portion and the closing member when the weather strip is installed on the vehicle and the closing member closes the opening. 
     In a further aspect, the present invention provides a weather strip for use on a vehicle comprising an engaging portion for engaging a closing member, the closing member operatively attached to the vehicle for closing an opening provided on the vehicle opening, and a weather strip body comprising a compressible portion and a magnetic sealing portion. The magnetic sealing portion provides a seal acting in a direction projecting toward a portion of the vehicle defined peripherally about the opening, wherein the magnetic sealing portion and the portion of the vehicle defined peripherally about the opening are magnetically attractive so as to provide a sealing interference between the magnetic sealing portion and the portion of the vehicle defined peripherally about the opening when the weather strip is installed on the vehicle and the closing member closes the opening. 
     The magnetically attraction between the sealing surfaces provides an airtight and watertight seal without requiring a high compression force, thus allowing the use of a weather strip that is more readily compressible than conventional vehicle weather strips. Accordingly, the weather strip may thus be produced to have an ease of compressibility so as to eliminate the need to slam the door. Furthermore, reducing the compression force reduces the force needed to operate door latches or other actuators and also allows smaller door latches or actuators to be employed in the manufacture of the vehicle. 
     In still a further aspect, the present invention provides a method for providing a sealing engagement employing the magnetic weather strip according to the present invention. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention and together with the general description, serve to explain the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The detailed description of the invention may be best understood when read in reference to the accompanying drawings wherein: 
     FIG. 1 is a side view of a motor vehicle to which a weather strip of the present invention is affixed; 
     FIG. 2 is a cross-sectional view of weather strips according to the present invention taken along line  2 — 2  in FIG. 1; 
     FIG. 3 is a cross-sectional view of an alternative embodiment of the present invention; 
     FIGS. 4-7 are cross-sectional views of several weather strips according to various embodiments of the present invention; 
     FIGS. 8-11 illustrate a sealing engagement between the magnetic weather strip according to the present invention and a magnetically attractive substrate wherein stripes of alternating polarity are employed; and 
     FIGS. 12 and 13 are cross-sectional views of additional embodiments of the present invention wherein the magnetic material of the weather strip does not directly contact the substrate. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1, weather stripping is used at a number of places on a motor vehicle, indicated generally by reference numeral  10 , for example between a door  12  closing an opening on the vehicle and the vehicle body  14 . In the specific embodiment shown in FIG. 1, weatherstrip  16  seals the entire periphery of the door opening bounded by vehicle body  14 . A second, optional, weather strip  18  is also shown, which provides additional sealing on the upper portion of the door opening. Additional weather stripping (not shown) may also be provided, for example, between the door  12  and rocker panel  17 . Although the present invention is described herein primarily by way of reference to a door  12  closing an opening to the passenger compartment of vehicle  10 , it will be recognized that the weather stripping in accordance with this teaching may be employed with all manner of overland vehicles, aircraft, water craft, and the like, having an opening thereon wherein it is desired to prevent penetration of wind, moisture, other environmental contamination into an interior compartment thereof, such as trunk opening  11 , hood opening  13 , and lamp housings  15 . In additional embodiments, the weather stripping according to the present invention may also be used to seal sliding doors, rear doors or tailgates, convertible tops, removable tops, roof openings such as sunroof openings, fuel filler doors, and the like. 
     Referring now to FIG. 2, there is shown a cross-sectional view of an exemplary arrangement of two weather strips in accordance with the present invention, designated generally as  16  and  18 , taken along the line  2 — 2  shown in FIG.  1 . Weather strip  16  is located around the periphery of an opening in vehicle body  14 . In the embodiment shown, an engaging portion  28  of weather strip  16  is attached to the vehicle body  14  with double-sided adhesive tape or other adhesive material  20 . Weather strip  16  faces inner edge  24  of door panel  12  with which it interacts. Also, an engaging portion  30  of optional weather strip  18  is attached with double-sided adhesive tape or other adhesive material  22  to inner edge  24  of door  12 . Weather strip  18  faces inwardly toward facing surface  26  of vehicle body  14  with which it interacts. 
     Weather strip  16  comprises a compressible portion  32  and a magnetic sealing portion  36  which interacts with surface  24  when door  12  is in its closed position. Likewise, optional weather strip  18  comprises a compressible portion  34  and a magnetic sealing portion  38  which interacts with surface  26  when door  12  is in its closed position. Compressible portions  32  and  34  of weather strips  16  and  18 , respectively, may comprise any flexible, compressible, and/or resilient material, such as flexible plastic or rubber, silicone, foam rubber, synthetic foam material, gels, and the like. Magnetic sealing portions  36  and  38  comprise a flexible, magnetic material, and preferably comprise a magnetic composite material comprising a flexible matrix or binder such as a flexible polymer material having magnetically hard particles dispersed therein. 
     The hard magnetic material may be any powdered or particulate materials capable of being permanently magnetically oriented as are generally known in the art. Exemplary permanent magnet particles include the rare earth metal alloy type materials, such as samarium-cobalt alloy particles, neodymium-iron-boron alloy particles, and the like. Other types of metal or metal-alloy permanent magnet particles may also be used, including Alnico (aluminum-nickel-cobalt-iron alloy), iron, iron-carbon, iron-cobalt, iron-cobalt-chromium, iron-cobalt-molybdenum, ironcobalt-vanadium, copper-nickel-iron, manganese-bismuth, manganese-aluminum, and cobalt-platinum alloys. Other magnetic materials are of the class of stable magnetic oxide materials known as the magnetic ferrites (including hexaferrites and cubic ferrites) such as barium ferrite, strontium ferrite, lead ferrite, or mixtures thereof, and which may be modified by partial substitution of the iron by many other elements such as cobalt. Other examples include magnetite (Fe 3 O 4 ), maghemite (γ-Fe 2 O 3 ), intermediates of magnetite and maghemite, and cobalt-substituted modifications of magnetite, maghemite, and their intermediates. Chromium dioxide is another material which may be useful as a magnetic particle in the present invention. Magnetic composites can be made with a variety of polymeric matrix components. The magnetic particles are dispersed within the composite at a loading sufficient to attain an efficient magnetic attraction of the weather strip for the magnetically attractive substrate. 
     Magnetic sealing portions  36  and  38  may be integrally formed with the compressible portions  32  and  34 , respectively, or, alternatively, may be separately formed and attached thereto. In the embodiment shown, the vehicle door  12  and vehicle body  14  are steel and thus magnetically attractive. In an embodiment (not shown), where the door or vehicle body (or the portion that accepts the seal) is not steel or other magnetically attractive material, a steel strip or other magnetically soft or magnetically attractive material such as a magnetically attractive composite material may be attached thereto. In certain embodiments, the magnetically attractive material is a soft magnetic composite comprising a polymeric matrix having magnetically soft particles or powder dispersed therein. In another embodiment (not shown), optional weather strip  18  may be a conventional nonmagnetic weather strip. Likewise, in yet another embodiment, optional weather strip  18  may be a magnetic weather strip in accordance with this teaching and weather strip  16  may be a conventional nonmagnetic weather strip. 
     Referring now to FIG. 3, there is shown a cross-sectional view of another exemplary embodiment of the present invention. Weather strip  316  is located around the periphery of an opening in vehicle body  314 . Weather strip  316  comprises an engaging portion  328  having a generally U-shaped cross-sectional shape which engages body panel flange  327 . Weather strip  316  may also be retained, for example, by body molding  340 , which may retain weather strip  316  in a bezel-type arrangement. Weather strip  316  faces inner edge  324  of door panel  312  with which it interacts. In the embodiment depicted, optional weather strip  318  is depicted as a conventional weather strip having a generally L-shaped cross-sectional shape attached to inner edge  326  of body  314  with double-sided adhesive tape or other adhesive material  322  and engages inner surface  324  of door  312 . Optional weather strip  318  need not circumscribe the entire door opening, but may be employed at significant locations such as on upper portions of the vehicle door opening, between the door and rocker panel, and so forth. In an alternative embodiment (not shown) optional weather strip  318  may be adapted to provide a magnetic weather strip in accordance with this teaching by providing a magnetic sealing surface thereon. 
     Weather strip  316  further comprises a compressible portion  332  integrally formed with engaging portion  328  and a magnetic sealing portion  336  which interacts with surface  324  when door  312  is in its closed position. Compressible portion  332  of weather strip  316  may comprise any resilient material, such as flexible plastic or rubber, silicone, foam rubber, synthetic foam material, gels, and the like, as described above. Magnetic sealing portion  336  is a flexible, magnetically hard material, and is preferably a magnetic composite material comprising a flexible polymer having permanent magnetic materials dispersed therein. Magnetic sealing portion  336  may be integrally formed with the compressible portion  332  or, alternatively, may be separately formed and attached thereto. 
     In alternative embodiments, not shown, the engaging portion of the weather strips according to the present invention may be fastened to a vehicle or vehicle door via a number of alternative methods, including, for example, chemical adhesives, a plurality of clips, screws, dogs, pawls, wire legs, and so forth spaced along the length of the weather strip, or the weather strip may have a flange formed thereon which may be retained via a tongue and groove arrangement or by a bezel which may be a fixture or molding such as a roof, door, or body molding, or other body feature. Also, a combination of adhesive and mechanical fasteners may also be employed. 
     Referring now to FIG. 4, there is shown in greater detail a weather strip  416  in accordance with a basic embodiment of the present invention. Weather strip  416  comprises an attachment portion  428  for attachment to a vehicle body or vehicle door, a compressible portion  432  comprising flexible walls, and a magnetic sealing portion  436 . Magnetic portion  436  may be prepared by dispersing magnetically hard particles into a flexible polymer. Again, the magnetic sealing portion and compressible portion may be separately formed and attached, or may be integrally formed. 
     FIG. 5 illustrates a weather strip  516  according to the present invention similar to that shown in FIG. 4, but wherein the magnetic sealing portion  536  is attached to compressible portion  632  by a tongue and groove arrangement. FIG. 6 illustrates a weather strip  616  according to the present invention wherein magnetic sealing portion  636  is integrally formed, e.g., via comolding, coextrusion, or other similar process, with compressible portion  632 . 
     Although the compressible portion of the weather strips in accordance with the present invention are primarily depicted herein as being hollow or tubular, in further embodiments, the compressible portion may comprise any compressible or resilient material. For example, FIG. 7 illustrates a weather strip  716  according to the present invention wherein magnetic portion  736  is attached to compressible portion  732  comprising a nontubular material such as a foam or other resilient or compressible material. In alternative embodiments (not shown) wherein a tubular compressible portion is employed, the tubular portion may contain one or more partitions, e.g., parallel to the axis of the weather strip. In still further embodiments, the cross-sectional shape of the weather strip according to the present invention may be modified to accommodate the surfaces to be sealed, for example, by varying the angles of the surfaces of the weather strip, incorporating one or more accordion folds into the compressible portion, and so forth. 
     Referring now to FIG. 8, a sectional view of an engagement between magnetic seal  836  and steel substrate  824  is shown. The magnetic attraction between substrate  824  and magnetic sealing portion  836  of weather strip  816  is increased by permanently magnetizing the magnetic composite forming the magnetic sealing surface  836  in a plurality of stripes  842  of alternating north-south polarity with the poles reversed in each adjacent stripe. This permits continuous magnetic flux through the steel substrate  824  and provides a stronger attraction than if the magnetic material of portion  836  were uniformly magnetized. Similarly, FIG. 9 illustrates a cross-sectional view of the sealing engagement between magnetic sealing surface  936 , magnetized in stripes  942  of alternating polarity, and a substrate  924  comprising a magnetically attractive composite material. 
     By employing stripes of alternating polarity, the magnetic attraction between the magnetic sealing portion and the magnetically attractive substrate is not only strengthened, but the distance over which the magnetic attraction ranges is decreased, thus eliminating the magnetic attraction between the weather strip according to the present invention and the door once the door is opened beyond a short distance from the weather strip, and also minimizing the attraction between foreign objects and the magnetic weather strip. The stripes of alternating polarity may be arranged in any direction along the plane formed by the surface of the magnetic sealing portion. In one embodiment, the stripes of alternating polarity are oriented along the surface of the magnetic sealing portion in a direction orthogonal to the axial direction of the weather strip. In another embodiment, the stripes of alternating polarity are oriented along the surface of the magnetic sealing portion in a direction diagonal with respect to the axial direction of the weather strip. The strips may be any desired width, and are preferably about 1/2 inch in width or less. 
     Referring now to FIG. 10, there is shown a sectional view of an engagement between magnetic seal  1036  and steel substrate  1024 . Magnetic seal  1036  comprises stripes of alternating polarity  1042  as described by way of reference to FIGS. 8 and 9, but with an additional magnetically attractive layer  1046  overlying the stripes of alternating polarity  1042 . Layer  1046  may be, for example, a magnetically soft composite or other magnetically soft material. In this manner, the magnetization curves around the top so that the magnetic sealing surface behaves as a series of horseshoe magnets. Similarly, FIG. 11 depicts a sectional view of an engagement between magnetic seal  1136  and steel substrate  1124  that is similar to that shown in FIG. 10, wherein magnetic seal  1136  is magnetized in a pattern of stripes  1142  of alternating north-south polarity that do not traverse the thickness of the seal  1136 . In this manner, magnetic seal  1136  comprises an integrally formed nonmagnetized layer  1146  overlying the stripes of alternating polarity  1042 , causing the seal  1136  to behave as a series of horseshoe magnets. 
     In each of the above described embodiments, the magnetic sealing portion of the weather strip according to the present invention forms a sealing engagement by direct contact between a magnetic material and an opposing magnetically attractive surface. As such, the ability to form a tight seal depends on the flexibility of the magnetic sealing surface. It will be recognized that the magnetic composite material forming the magnetic sealing portion may be made more flexible by decreasing the concentration of magnetic material in the composite, however, the strength of magnetic attraction/adhesion will also decrease. FIG. 12 illustrates a weather strip  1216  according to the present invention wherein magnetic sealing portion  1236  comprises a magnetic layer  1244  and a flexible contact layer  1248 . Flexible contact layer  1248  may be any flexible, resilient, or compressible material, such as flexible plastic or rubber, foam rubber, synthetic foam material, gels, and the like, and is disposed between the magnetic layer  1244  and a sealingly engaged surface. In this manner, magnetic layer  1244  may have a sufficient concentration of magnetically hard materials dispersed therein to achieve a desired strength magnetic attraction, with flexible contact layer  1248  providing the necessary flexibility. In one embodiment, the flexible contact layer does not contain any magnetic or magnetically attractive materials dispersed therein. In another embodiment, the flexible contact layer may be a flexible composite material having a magnetically attractive material dispersed therein. In still another embodiment, the flexible contact layer may be a flexible composite material having a magnetically hard material dispersed therein, e.g., at a lower concentration than magnetic layer  1244 . In an embodiment not shown, a high strength magnetic sealing portion may be achieved, while retaining flexibility at the contact surface, by employing a magnetic sealing portion comprising a magnetically hard composite material wherein the concentration of magnetically hard materials in the composite is increased near the base of the magnetic sealing portion and is decreased near the contact surface to provide flexibility, e.g., wherein a plurality of discrete concentration levels are provided, or alternatively, wherein a graduated concentration is provided. Any of the embodiments shown and described herein of the magnetic weather strip of the present invention may be modified to employ the flexible contact layer in accordance with this teaching. 
     Referring now to FIG. 13, there is shown a magnetic weather strip  1316  in accordance with the present invention having a generally tubular or hollow cross-section and having a sleeve retaining magnetic seal  1336  within the interior of weather strip  1316  and a foam or hollow interior  1354 . The sleeve retaining magnetic portion  1336  is bounded by interior partition  1350  and upper surface  1348 . Upper surface  1348  provides a flexible contact surface for engaging a magnetically attractive substrate on a vehicle. In an embodiment not shown partition  1350  may be omitted and magnetic seal  1336  may be retained in the interior of weather strip  1316  by an adhesive or other fastening means. Likewise, in a further embodiment, not shown, partition  1350  may be omitted and the hollow portion of weather strip  1316  may be sized to securely accommodate magnetic portion  1336 . In still another embodiment, not shown, partition  1350  may be omitted and magnetic portion  1336  retained in place with a compressible material, e.g., a foam material, occupying the remainder the interior of weather strip  1316 . 
     The description above should not be construed as limiting the scope of the invention, but as merely providing illustrations to some of the presently preferred embodiments of this invention. In light of the above description and examples, various other modifications and variations will now become apparent to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims. Accordingly, the scope of the invention should be determined solely by the appended claims and their legal equivalents.