Abstract:
A wiper blade for a windshield wiper blade refill includes a crown located at the top of the wiper blade. The bottom of the wiper blade has a windshield-engaging lip. A neck extends from the crown toward the lip, and the neck increases in width in a direction away from the crown.

Description:
This application is a continuation of application Ser. No. 08/926,427, filed Sep. 10, 1997, now U.S. Pat. No. 6,163,922. 
    
    
     BACKGROUND 
     The invention relates to a wiper blade for a windshield wiper blade refill. 
     In general, as shown in FIGS. 5 and 6, a windshield wiper blade carrier may have a wrap-around metal claw  20  that holds a wiper blade refill  900 . The refill  900  has a wiper blade  910 , which typically is made of rubber, mounted within a plastic flexor  920 . The flexor  920  mates with the claw  20  to attach the refill  900  to the carrier  10 . The wiper blade  910  includes a crown  930 , a neck  940  and a bumper  950  that secure the blade  910  in the flexor  920 . The wiper blade  910  also has a hinge  960  that bends to allow a body portion  970  to move relative to the rest of the blade  910  as the wiper moves back and forth across the windshield. A lip  980  makes contact with the surface of the windshield to remove water from the windshield. 
     SUMMARY 
     In one aspect, generally, the invention features a wiper blade that has a crown at the top. A windshield-engaging lip is located at the bottom of the wiper blade. A neck extends from the crown toward the lip, and the neck increases in width in the direction away from the crown. 
     Embodiments may include one or more of the following features. The crown may be trapezoidal in shape. The neck may include sides that form an angle of greater than six degrees. The wiper blade may include a bumper that extends from the neck and that has an underside surface. A hinge may extend from the underside surface of the bumper. A body may extend from the hinge and may be configured to pivot about the hinge. The windshield-engaging lip may. be formed at the bottom end of the body. 
     A wiper blade refill may include the wiper blade described above and a flexor. The flexor may have a top portion that conforms in shape to the crown of the wiper blade. The flexor also may have a neck portion that conforms in shape to the neck of the wiper blade. The flexor may include a bottom edge strip that may extend from the bottom end of the flexor. The portion of the flexor that corresponds to the underside surface of the top portion of the wiper blade may be a flat surface that is parallel to the bottom edge strip. 
     In another aspect, a wiper blade refill is configured to be installed in the wrap-around claw of a wiper blade carrier. The wiper blade refill includes a wiper blade that has a top portion and a neck portion. The wiper blade refill also includes a flexor that conforms in shape to the top and neck portions of the wiper blade. The neck portion of the wiper blade increases in width in the direction away from the top portion of the wiper blade. 
     Embodiments may include one or more of the following features. The top portion of the wiper blade may be trapezoidal in shape. The neck portion may include sides that form an angle of greater than six degrees. The top portion of the wiper blade may be configured to be positioned within the wrap-around claw. 
     In another aspect, a flexor is configured to mate with a wiper blade that has a crown at the top, a windshield-engaging lip at the bottom, and a neck that extends from the crown toward the lip. The neck increases in width in the direction away from the crown. The flexor includes a top portion that conforms in shape to the crown of the wiper blade, a neck portion that conforms in shape to the neck of the wiper blade, and a bottom edge strip. 
     Embodiments may include one or more of the following features. The portion of the flexor that corresponds to the underside surface of the crown of the wiper blade may be a flat surface that is parallel to the bottom edge strip. The flexor may be trapezoidal in shape. 
     Other features and advantages will be apparent from the following detailed description, including the drawings, and from the claims. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a wiper blade installed in a wiper blade carrier. 
     FIG. 2 is a sectional view of the wiper blade and carrier of FIG.  1 . 
     FIG. 3 is a sectional view of the wiper blade of FIG.  1 . 
     FIG. 4 is a sectional view of a wiper blade installed in a wiper blade carrier. 
     FIG. 5 is a perspective view of a wiper blade and wiper blade carrier. 
     FIG. 6 is a sectional view of the wiper blade and carrier of FIG.  5 . 
    
    
     DESCRIPTION 
     Referring to FIGS. 1 and 2, a wiper blade refill  100  is mounted in a wiper blade carrier  10  having a wrap-around metal claw  20 . The refill  100  includes a wiper blade  110 , made of a solid, flexible material such as rubber. The wiper blade  110  is mounted within a flexor  120 , typically made of plastic, which attaches the wiper blade  110  securely to the claw  20 . The flexor  120  is generally trapezoidal in shape. 
     A thick, tapered crown  130  defines the top of the wipe blade  110 . Below the crown is a wedge-shaped neck  140  that is narrow at the top and wide at the bottom. The crown  130  and neck  140  fit within the trapezoidally shaped flexor  120 , while the rest of the wiper blade  110  extends from the bottom of the flexor  120 . A wide, rectangular bumper  150  at the base of the neck  140  cooperates with the crown  130  and the neck  140  to hold the wiper blade  110  in position within the flexor  120 . 
     A narrow hinge  160  and a triangular body  170  are formed below the bumper  150 . The body  170  pivots about the hinge  160  as the wiper blade  110  is moved back and forth across the windshield. The body  170  narrows at the bottom to a lip  180  that contacts the surface of the windshield and removes water from the windshield. 
     Placement of the crown  130  and part of the neck  140  within the claw  20  reduces the overall height of the wiper blade assembly above the windshield compared to wiper assemblies that suspend the wiper blade below the claw, such as the one shown in FIGS. 5 and 6. The reduced height reduces wind lift forces, which otherwise are caused by high velocity wind and which would tend to lift the wiper blade from the surface of the windshield. The reduced height also results in a smaller moment arm which reduces bending forces on the upper portion of the wiper blade. 
     The trapezoidal shape of the crown  130  and the flexor  120  provide improved mating between the wrap-around claw  20  and the refill  100 . The portions of the flexor  120  corresponding to the bottom of the crown  130  provide flat surfaces  121  that are parallel to upper surfaces  21  at the ends of the claw  20 . The surfaces  121  cooperate with the bottom edge strip  124  of the flexor to prevent movement of the crown  130  and neck  140  portions of the wiper blade  110 . 
     The bumper  150  mates closely with the bottom edge strip  124  to prevent excessive bending of the neck  140 . 
     Computer modeling has shown that significant tensile and compressive forces occur in the neck  140  during operation of the wiper blade. Ideally, the hinge-like bending of the wiper blade  110  should occur in the hinge  160  rather than in the neck  140  or other portions of the blade. Therefore, as shown in FIG. 3, the neck  140  is wedge-shaped, i.e. narrower at the top portion  148  and wider at the bottom portion  146 , where tensile and compressive forces are greatest. This configuration reduces the likelihood of failure of the wiper blade  110  during operation. 
     The wedge-shaped neck also reduces the likelihood of permanent deformation of the neck  140 , which may occur while the wiper blade assembly is “parked” in its resting position at the bottom of the windshield. This deformation, caused by the blade resting for long periods in a bent position, may cause chattering noise or non-uniform wiping during operation. In addition, the wedge-shaped neck  140  seats into a mating wedge-shaped portion of the flexor  122 , as shown in FIG.  2 . This configuration provides additional stability to the wiper blade  110  and further reduces the possibility of deformation of the neck  140 . 
     Another advantage of the wedge-shaped neck  140  is that it provides a greater ratio between the width of the crown, W c , and the width of the neck, W n , resulting in a greater retention force between the wiper blade  110  and the flexor  120 . The increased retention force prevents the wiper blade  110  from being pulled out of the flexor  120  during operation, which could lead to loss of the blade and scratching of the windshield surface. 
     The angle of the wedge, θ, may be selected to optimize the characteristics discussed above. For example, FIG. 3 shows a wedge angle of approximately 30°, however other wedge angles may be used. As a further example, testing has been performed on wiper blades having a wedge angle of 6°. 
     Referring to FIG. 4, in an alternative embodiment, a metal clip  190  provides support to a refill  200 . To provide space for the metal clip  190 , the wiper blade  210  includes a wide, thin crown  230 . The increased width, W c ′, of the crown  230  compensates for the reduced thickness, T c , of the crown  230  to ensure that sufficient retention forces are provided to retain the wiper blade  210  in the flexor  220 . The top portion of the flexor  220  is wider and shorter than in the first embodiment to accommodate the wide, thin crown  230 . As in the first embodiment, the neck  240  is narrow at the top near the crown  230  and wide at the bottom near the bumper  250 . Also, portions of the flexor  220  corresponding to the bottom of the crown provide flat surfaces  221  that are parallel to upper surfaces  21  at the ends of the claw  20 . The surfaces  221  cooperate with the bottom edge strip  224  of the flexor to prevent movement of the crown  230  and neck  240  portions of the wiper blade  210 . The bumper  250  mates closely with the bottom edge strip  224  to prevent excessive bending of the neck  240 . 
     Other embodiments are within the scope of the following claims.