Patent Document

BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates generally to heavy-duty flat wiper blade assemblies. 
     2. Related Art 
     Heavy-duty flat wiper blade assemblies are known having a straight body mounting a rubber wiper element. In one known construction, the body is extruded from a plastic which is, in turn, reinforced by a metal stiffener to provide sufficient structural rigidity to the body, as shown in U.S. Pat. No. 3,107,384. In another known construction, the body is fabricated from a strip of steel which is bent into a generally U-shaped profile in cross-section and crimped along its length to the rubber wiper element to secure the wiper element. In this case, the flat steel body component is cut to length along with the wiper element prior to folding the flat steel over the wiper element. 
     Both such constructions are costly to manufacture and are limited in the features and advantages they can offer. 
     Heavy-duty flat wiper blade assemblies constructed according to the present invention overcome or greatly minimize the foregoing limitations of prior wiper blade assemblies. 
     SUMMARY OF THE INVENTION 
     A heavy-duty flat wiper blade assembly has a wiper element and an extruded metallic frame. The frame has a bottom channel with a slot and an upper channel separate from the bottom channel. The wiper element is disposed in the bottom channel and extends through the slot to make contact with a surface to be wiped. The upper channel is closed and may optionally be provided with a fluid inlet opening for receiving wiper fluid into the channel and a fluid outlet opening for discharging the wiper fluid from the upper channel and onto a surface to be wiped. 
     Additionally, a method for manufacturing a wiper blade is provided wherein a wiper element is slidably inserted into a bottom channel of an extruded metallic frame. The wiper element depends from the bottom channel and through a slot in the bottom channel to make wiping contact with a surface to be wiped. A wall of the bottom channel is then staked to fix the wiper element within the bottom channel. An optional method eliminates the staking step and installs a pair of end plugs into each end of the frame to releasably maintain the wiper element within the bottom channel. 
     Some advantages of the invention include providing for increased efficiencies in the manufacture and assembly of a heavy-duty wiper blade assembly by reducing the number of operations required to produce the wiper blade assembly, by reducing the scrap, by improving the handling of the wiper blade components during assembly and by reducing the time required for assembly, thus reducing the total costs of producing the wiper blade assembly. 
     Another advantage of the invention is the ability to utilize the closed upper channel as a passage for conveying wiper fluid from which the fluid may be dispensed directly on the surface to be wiped. 
     Another advantage of the invention is a reduction in the amount of material used in the wiper element. 
    
    
     THE DRAWINGS 
     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: 
     FIG. 1 is a perspective view of a wiper blade assembly showing a first preferred embodiment of the present invention; 
     FIG. 2 is a cross-sectional view taken generally along lines  2 — 2  of FIG. 1; 
     FIG. 3 is a front elevation view of a second embodiment of the present invention; 
     FIG. 4 is a fragmentary isometric view of the blade assembly of FIG. 3; 
     FIG. 5 is a cross-sectional view taken generally along lines  5 — 5  of FIG. 4; 
     FIG. 6 is a cross-sectional view taken generally along lines  6 — 6  of FIG. 4; and 
     FIG. 7 is an enlarged fragmentary elevation view, shown partly in section, of FIG.  4 . 
    
    
     DETAILED DESCRIPTION 
     FIGS. 1 and 2 show a heavy-duty wiper blade assembly  10  constructed according to a first preferred embodiment of the present invention. The wiper blade assembly  10  has an extruded frame  12  having a bottom channel  14  that receives a wiper element  16 , and an upper channel  18  that is separate from the bottom channel  14 . The wiper element  16  is slidably received in the bottom channel  14  and is maintained in the bottom channel  14  by a protuberance or preferably a plurality of protuberances  20 . 
     The frame  12  of the wiper blade assembly  10  is extruded into one integral member from a metallic material, such as aluminum, or any other extrudable metallic material. The finished frame  12  has a pair of ends  24 ,  26 . The bottom channel  14  and upper channel  18  extend between the ends  24 ,  26 . 
     The bottom channel  14  has slot  28  formed along the bottom channel  14  between the pair of ends  24 ,  26  having openings  27 ,  29  such that a bottom surface  30  of the bottom channel  14  preferably has a pair of opposing lips  31 ,  32  extending generally toward one another, thus causing the bottom channel  14  to be generally C-shaped in cross-section, as shown best in FIG.  2 . 
     The upper channel  18  of the frame  12  is a generally closed channel other than openings  34 ,  36  at the ends  24 ,  26  of the frame  12 , and an aperture  38  formed in a sidewall or opposing sidewalls  40 ,  42  of the upper channel  18  between the ends  24 ,  26  of the frame  12 . 
     The aperture  38  formed in the opposing sidewalls  40 ,  42  of the upper channel  18  is preferably formed equidistant from either end  24 ,  26  and receives a mounting pin (not shown) therethrough so that the wiper blade assembly  10  can be attached to a wiper arm (not shown). 
     As best shown in FIG. 2, the wiper element  16  has a crown portion  44 , a neck portion  46 , a bumper portion  48 , a hinge portion  50 , and a body portion  52 . The wiper element  16  is received by the bottom channel  14  by sliding the crown portion  44  of the wiper element  16  into one of the openings  27 ,  29  of the bottom channel  14 . The pair of opposing lips  31 ,  32  forming the bottom surface  30  of the bottom channel  14  extend generally inwardly toward the neck portion  46  such that they capture and releasably maintain the wiper element  16 . Though the wiper element  16  is releasably maintained within the channel  14  by the lips  31 ,  32 , the wiper element  16  is still able to slide transversely within the bottom channel  14 . 
     Preferably, the crown portion  44  of the wiper element  16  conforms generally in shape to the bottom channel  14 . A bottom surface  53  of the crown portion  44  is preferably in mating contact with an upper surface  54  of the lips  31 ,  32  such that the crown portion  44  is maintained within the bottom channel  14  during assembly  10 . The neck portion  46  of the wiper element  16  depends from the crown portion  44  and passes between the lips  31 ,  32  of the frame  12  and joins the bumper portion  48  of the wiper element  16 . The bumper portion  48  of the wiper element  16  contacts the bottom surface  30  of the lips  31 ,  32 . The wiper element  16  can be secured against relative sliding movement within the channel  14  by staking a sidewall or sidewalls  40 ,  42  of the bottom channel  14 , such that a plurality of protuberances  20  extend laterally inwardly into gripping engagement with the crown portion  44  of the wiper element  16 . As shown in FIG. 1, preferably two protuberances  20  are staked adjacent each end  24 ,  26  of each side-wall  40 ,  42  of the frame  12 . However, it should be recognized that any number of protuberances  20  may be staked depending on the requirements of the wiper blade application. 
     FIGS. 3-7 show an alternative embodiment of a wiper blade assembly of the invention generally at  110 . The same reference numerals are used to designate like features to those of the first embodiment, but are offset by 100. The assembly  110  includes an upper channel  118  in which a pair of end plugs  22 ,  23  are installed. The channel  118  communicates with a source of pressurized wiper fluid (not shown) through one of the end plugs  22 ,  23 . The wiper fluid can travel through and be dispensed from the upper channel  118  directly onto the surface to be wiped by the wiper blade assembly  110 . Also, the wiper element  116  is preferably releasably maintained in the bottom channel  114  by a bottom portion  56  of the pair of end plugs  22 ,  23 , thus enabling the wiper element  116  to be quickly and easily replaced when needed. It should be recognized however, that a staking operation could be used here as performed in the first preferred embodiment. 
     The pair of end plugs  22 ,  23  are preferably sized so that they can be press fit into the openings  134 ,  136  at the ends  124 ,  126  of the upper channel  118  such that they have an interference fit or other suitable mechanical retention (e.g. latches), and create a generally fluid tight seal therein. The end plugs  22 ,  23  are shaped to have a plug portion  58  that fits within the upper channel  118 , and a face portion  60  that remains in mating contact with an end  124 ,  126  of the frame  112 . One end plug  22  preferably has a through hole  62  such that a hose  64  can be connected in the through hole  62  of the end plug  22  to provide for communication of fluid between the upper channel  118  and the source of pressurized wiper fluid. The wiper fluid can then be received within the upper channel  118  of the wiper blade assembly  110  and be dispensed from the upper channel  118  through a nozzle  64  and directed onto the surface to be wiped by the wiper blade assembly  110 . It should be recognized however, that the hose  64  could be received in an opening anywhere along the upper channel  118  between the two ends  24 ,  26  of the upper channel  118 , and not through one of the end plugs  22 ,  23  in the pair of ends  124 ,  126  of the frame  112 . 
     The end plugs  22 ,  23  preferably extend downwardly from the upper channel  118  so that the face portion  60  blocks or covers at least a portion of the bottom channel  114 . With at least one end plug  22 ,  23  removed from the bottom channel  114 , the wiper element  116  can be slidably received within the bottom channel  114 , and the end plug or end plugs  22 ,  23  can then be press fit into the bottom channel  114 . The face portions  60  of the plugs  22 ,  23  then releasably maintain the wiper element  116  within the bottom channel  114 . If the wiper element  116  needs replacing, one of the end plugs  22 ,  23  can simply be removed to slidably remove the wiper element  116  from the bottom channel. 
     As best shown in FIG. 6, another opening  66  in one of the side walls  40 ,  42  of the upper channel  118  has the nozzle  64  received therein. The nozzle  64  is fixed in the opening  66  of the upper channel  118  such that the nozzle  64  is maintained in sealing engagement with the opening  66 . The nozzle  64  has a through hole  68  that is formed to dispense wiper fluid from the upper channel  118  such that the wiper fluid exits preferably in a desired spray pattern. The nozzle  64  is shown here to be generally equidistant between the two ends  24 ,  26  of the upper channel  118 . It should be recognized however, that the opening  66  used to receive the nozzle  64  can be placed anywhere along the length between the two ends  24 ,  26  of the upper channel  118 , as best suited for the application. It should also be recognized that any number of nozzles  64  can be employed within the sidewalls  140 ,  142  to insure adequate coverage of wiper fluid on the surface to be wiped by the wiper blade assembly  110 . 
     As best shown in FIG. 5, a grommet  70  is installed in the aperture  138  to create a fluid tight seal between the mounting pin and the upper channel  118  to prevent any wiper fluid from leaking between the aperture  138  and the mounting pin. Ends  72 ,  74  of the grommet  70  are formed with radially enlarged flanges  76 ,  78  for securing and sealing the grommet  70  within the aperture  138 . The grommet  70  has a tubular body passing through the upper channel  118 , defining a through hole  80  for accommodating the mounting pin (not shown). Other suitable means for creating a seal between the aperture  138  and the mounting pin to prevent wiper fluid from exiting the aperture  138  is contemplated by this invention, such as applying a coating to the walls of the aperture  138  or to the mounting pin so that the coating provides a fluid-tight seal. 
     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. The invention is defined by the claims.

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