Abstract:
A singular wiper for wiping multiple and independent surfaces which obviates the conventional need for a wiper respectively for each of the surfaces. The wiper includes a wiper motor assembly, a wiper arm connected to the wiper motor assembly, a blade assembly connected to the wiper arm, and a cam having a cam profile. The wiper motor assembly reciprocates the wiper arm and thereby reciprocates the blade assembly over a predetermined range of reciprocation. The cam profile interacts with the wiper arm in a normal direction that is perpendicular to the plane of reciprocation of the wiper assembly so as to selectively regulate contact of the blade assembly with various surfaces disposed in the range of reciprocation of the blade assembly.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates to wipers used in automotive applications for wiping glass surfaces, and more particularly to a singular wiper which is capable of wiping multiple and independent glass surfaces.  
         BACKGROUND OF THE INVENTION  
         [0002]    Motor vehicles having rear gate/door glass are frequently equipped with one or more wipers, a wiper being needed for each independent glass surface. As shown at FIG. 1, motor vehicles  10  having two side-hinged doors  12 L,  12 R also have two independent rear glasses  14 L,  14 R. Conventionally, for each rear glass  14 L,  14 R a separate wiper  16 L,  16 R must be respectively provided. The reason for this is the multiplicity and independence of the rear glasses  14 L,  14 R. A wiper  16 L which wipes the glass surface  18 L of one rear glass  14 L cannot wipe the glass surface  18 R of the other rear glass  14 R because they are separated by a discontinuity  20  in the form of elevated door skins  22 L,  22 R and the gap  24  between the doors.  
           [0003]    A separate wiper for each multiple and independent glass surface requires a multiplicity of wipers, as well as the assembly costs for the necessary multiple installations on a single vehicle. Additionally each of the multiple installations involve added weight, wiring and servicing.  
           [0004]    Accordingly, if a single wiper could somehow wipe multiple and independent surfaces, then a number of advantages would be realized as compared to the conventional practice of providing at least one wiper per glass surface, including: improvement of visibility, increased driver satisfaction, reduction of cost and weight, and better durability and dependability inherently emanating from a single wiper servicing multiple and independent surfaces.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention is a singular wiper for wiping multiple and independent surfaces which obviates the conventional need for a wiper respectively for each of the surfaces.  
           [0006]    The wiper for multiple and independent surfaces includes a wiper motor assembly, a wiper arm connected to the wiper motor assembly, a blade assembly connected to the wiper arm, and a cam having a cam profile. The wiper motor assembly reciprocates the wiper arm and thereby reciprocates the blade assembly over a predetermined range of reciprocation. The cam profile interacts with the wiper arm in a normal direction that is generally perpendicular to the plane of reciprocation of the wiper assembly so as to selectively regulate contact of the blade assembly with various surfaces disposed in the range of reciprocation of the blade assembly.  
           [0007]    In an example of operation, a motor vehicle has left and right rear doors, each being provided with a rear glass that is independent of the other. The wiper motor assembly is mounted upon either the left or the right rear door, and the cam is also mounted thereto. The blade assembly reciprocates over a range of reciprocation which includes both rear glasses. In operation, during reciprocation of the wiper arm, the blade assembly wipes the surfaces of both of the rear glasses. The wiper arm is guidably moved in a normal direction by the cam profile, wherein the blade assembly translates away at portions of the drop glasses adjacent the discontinuity between the rear glasses so as to non-contactingly traverse the discontinuity. By way of example, the discontinuity may include rear door skin that is elevated in relation to the rear glass surfaces, which skin is non-contactingly traversed during reciprocation.  
           [0008]    Accordingly, it is an object of the present invention to provide a singular wiper apparatus which is capable of wiping multiple and independent surfaces.  
           [0009]    This and additional objects, features and advantages of the present invention will become clearer from the following specification of a preferred embodiment.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a perspective, broken-away, rear view of a motor vehicle equipped with a pair of prior art wipers, one wiper respectively for wiping each of its two independent rear glass surfaces.  
         [0011]    [0011]FIG. 2 is a perspective, broken-away, rear view of a motor vehicle equipped with a wiper for multiple and independent surfaces according to the present invention for wiping both of its two independent rear glass surfaces.  
         [0012]    [0012]FIG. 3 is a rear view of a motor vehicle equipped with the wiper for multiple and independent surfaces according to the present invention, wherein the blade assembly is at a first position of its range of reciprocation.  
         [0013]    [0013]FIG. 3A is a sectional view seen along line  3 A- 3 A.  
         [0014]    [0014]FIG. 4 is a rear view of a motor vehicle equipped with the wiper for multiple and independent surfaces according to the present invention, wherein the blade assembly is at a second position of its range of reciprocation.  
         [0015]    [0015]FIG. 4A is a partly perspective view seen along line  4 A- 4 A in FIG. 4.  
         [0016]    [0016]FIG. 4B is a partly sectional view seen along line  4 B- 4 B in FIG. 4.  
         [0017]    [0017]FIG. 5 is a rear view of a motor vehicle equipped with the wiper for multiple and independent surfaces according to the present invention, wherein the blade assembly is at a third position of its range of reciprocation.  
         [0018]    [0018]FIG. 5A is a partly perspective view seen along line  5 A- 5 A in FIG. 5.  
         [0019]    [0019]FIG. 5B is a partly sectional view seen along line  5 B- 5 B in FIG. 5.  
         [0020]    [0020]FIG. 6 is a rear view of a motor vehicle equipped with the wiper for multiple and independent surfaces according to the present invention, wherein the blade assembly is at a fourth position of its range of reciprocation.  
         [0021]    [0021]FIG. 7 is a rear view of a motor vehicle equipped with the wiper for multiple and independent surfaces according to the present invention, wherein the blade assembly is at an optional parked position beyond its range of reciprocation.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]    Referring now to the Drawings, FIGS. 2 through 7 depict an example of a wiper for multiple and independent surfaces  100  (hereinafter referred to simply as a “MIS wiper”). As shown schematically at FIG. 2, the MIS wiper  100  includes a wipe motor assembly  102 , a wiper arm  104  which is connected to the wiper motor assembly so as to be reciprocated thereby, a blade assembly  106  carried by the wiper arm at a distal end thereof, and a cam  108  for regulating normal movement (that is, perpendicular movement to the plane of reciprocation) of the blade assembly. The wiper motor assembly  102  causes the wiper arm  104  to reciprocate such that the blade assembly reciprocates over a range of reciprocation. The cam  108  has a cam profile  110  which the wiper arm  104  follows during one or more selected portions of the reciprocation, wherein the normal movement regulated thereby is perpendicular to the plane of reciprocation of the wiper blade assembly and away from the one or more surfaces being wiped by the blade assembly during reciprocation.  
         [0023]    It will be noted from FIG. 2, which is an exemplification of an environment of operation of the MIS wiper  100  according to the present invention, a motor vehicle  112  has a pair of side-hinged doors  114 L,  114 R. Each door  114 L,  114 R has a respective rear glass  116 L,  116 R. The respective surface  118 L,  118 R of each of the rear glasses  116 L,  116 R is wiped by a single MIS wiper  100 . By way of example, the wiper motor assembly  102  is mounted to the left door  114 L, as is the cam  108 . However, the wiper motor assembly  102  may be mounted to the right door, or otherwise (as for example on the roof); further the cam may be mounted otherwise, including straddling the doors or incorporation into existing components such as for example glass encapsulation, so long as it performs the cam following operation for the wiper arm  104  as described herein.  
         [0024]    The range of reciprocation includes the two surfaces  118 L,  118 R, each being independent of the other by a surface discontinuity  122 . The surface discontinuity  122  includes door skins  124 L,  124 R and the gap  126  therebetween. The wiper motor assembly  102  biases the wiper arm  104  toward the surfaces  118 L,  118 R so that as the blade assembly  106  reciprocates thereover, the wiper blade  128  thereof pressably wipes thereacross. The door skins  124 L,  124 R are elevated relative to the surfaces  118 L,  118 R with an abrupt interface  124 I, and further have edges  124 E at the gap  126 . Accordingly, the wiper blade would be soon ruined if it were to wipe contactingly over the surface discontinuity  122 .  
         [0025]    The cam  108  is located so that the cam profile  110  thereof guides the wiper arm  104  so as to regulate the normal movement of the wiper assembly  106  such that the wiper blade makes no contact with any surfaces at the surface discontinuity  122 . In a preferred form, the cam profile  110  has a generally convex shape which includes at either end up/down ramps  110 ′,  110 ″ for normally translating the wiper arm and keeping that translation at least sufficient for the wiper blade  128  to noncontactingly pass over all surfaces of the surface discontinuity  122 .  
         [0026]    Turning attention now to FIGS. 3 through 6 an example of operational movements of the MIS wiper  100  will be detailed, wherein the locations of the ramps  110 ′,  110 ″ (see FIG. 4A) of the cam profile  110 , the location of the center of rotation C of the wiper arm  104 , the shape and length of the wiper arm (as for example the acutely bent shape shown), the length of the wiper blade  128 , and the range of reciprocation  120  are collectively predetermined so that the wiper blade provides a suitable area of wiping of the surfaces  118 L,  118 R.  
         [0027]    [0027]FIG. 3 depicts the wiper assembly  106  at a first extreme position  1201  of the range of reciprocation  120 . As shown at FIG. 3A, the wiper blade  128  is biased toward the surface  118 L so that as the wiper assembly reciprocates, the surface is wiped by the blade.  
         [0028]    At FIG. 4, the wiper assembly  106  has reciprocated to adjacency with a first abrupt interface  124 I of the surface discontinuity  122 . Simultaneously, the wiper arm  104  has reciprocated into engagement with the cam  108 . A cam follower  104 C of the wiper arm  104  engages the cam profile  110  (see FIG. 4A). The cam follower  104 C may be any suitably configured surface of the wiper arm for low friction, smooth sliding. Sliding friction is preferably minimized by choice of materials for the cam profile  110  and the cam follower  104 C, so as to achieve excellent lubricity and wear resistance, as for example DELRIN®, generically known as acetel. Alternatively, the cam follower  104 C may be a roller bearing. A first ramp  110 ′ of the cam profile  110  provides a normal movement T in a direction perpendicular to the plane of reciprocation, at least as large as the height H of any surface of the surface discontinuity  122  relative to the wiping surfaces  118 L,  118 R (see FIG. 4B).  
         [0029]    At FIG. 5, the wiper assembly  106  has passed noncontactingly over the surface discontinuity  122 . The cam follower  104 C has followed the second ramp  110 ″ which results in the wiper blade  128  translating toward the surface  118 R so that it is now contacting the surface  118 R and biased thereagainst (see FIGS. 5A and 5B).  
         [0030]    At FIG. 6, the wiper assembly  106  has reached a second extreme position  1202  of the range of reciprocation  120  (see FIG. 3), wherein the wiper blade has wiped across the surface  118 R.  
         [0031]    The reciprocation direction is now reversed by the wiper motor assembly  102 . During the reverse reciprocation, the cam follower  104 C of the wiper arm  104  encounters the cam  108 , wherein the first and second ramps  110 ′,  110 ″ of the cam profile  110  again provide normal translations of the wiper arm such that the surfaces  118 L,  118 R are wiped and the wiper blade  128  noncontactingly passes over the surface discontinuity  122 .  
         [0032]    A preferred park location of the wiper arm  104  is shown at FIG. 3. (Parking the wiper assembly straddling the surface discontinuity  122  is not viable since this would interfere with door operation and would nakedly expose the wiper assembly when the doors are opened). When the driver turns off the MIS wiper  100 , known regulating electronics automatically parks the wiper arm at the FIG. 3 position.  
         [0033]    An alternative park position is depicted at FIG. 7. Now, the regulating electronics automatically parks the wiper arm  104  by an over-arc beyond the range of reciprocation  120  onto a parking cam  130 . Parking cams for wipers are well known in the art. This parking alternative has the advantage that when parked, the wiper assembly does not block the rear glass, allowing for unfettered view therethrough, and/or reciprocation of the rear glass.  
         [0034]    To those skilled in the art to which this invention appertains, the above described preferred embodiment may be subject to change or modification. For example, it is to be understood that while a single surface discontinuity between two adjacent wiping surfaces are shown and discussed herein, that any number of discontinuities and wiping surfaces may be accommodated by the MIS wiper according to the present invention. Further, while an arcing reciprocation is disclosed in detail herein, from such disclosure a person of ordinary skill is enabled to utilize the cam and wiper arm concept herein with respect to a lateral (a straight back and forth) reciprocation. Such change or modification can be carried out without departing from the scope of the invention, which is intended to be limited only by the scope of the appended claims.