Windshield wiper superstructure with airfoil

A vehicle wiper for use with a vehicle windshield includes a first lever having opposing end portions, a plurality of second levers supporting a rubber wiper blade, the first lever having the second levers pivotably connected to the end portions of the first lever while being pivotably held to a wiper arm at an intermediate portion of the first lever. The first lever includes a first mounting portion having spaced, opposing sides and a pair of walls defined at the opposing sides so as to permit the first lever to be mounted to the wiper arm and a pair of second mounting portions, each having a pair of walls spaced apart from each other. A fin portion is defined between the first mounting portion and the second mounting portion and extends from the first and second mounting portions. The fin portion has a rear edge portion formed at a top portion thereof, thereby preventing the wiper blade from being lifted from the windshield so as to wipe against the windshield when the vehicle travels at high speed. Twisted portions integrally combine the fin portion with the first mounting portion as well as the second mounting portion, in such a manner that the fin portion is joined smoothly and continuously and is integral with a front wall of the first mounting portion and a front wall of the second mounting portion.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a vehicle wiper for squeegeeing a 
windshield and the like of an automobile. 
2. Description of the Related Art 
In vehicle wipers for squeegeeing a windshield and the like of automobiles, 
there is a so-called tournament type wiper (i.e., a wiper having a 
hierarchical tree structure) now in general use. This type of wiper has 
the wiping-ability of even wiping a curvilinear windshield. The 
curvilinear windshield is thereby wiped completely. 
The above tournament type wiper has a wiper blade which includes one rubber 
blade and a plurality of levers. The levers further include one first 
lever and a plurality of second levers. The second levers are held to the 
first lever which in turn is pivotably held to an arm piece of a wiper 
arm. Furthermore, the rubber blade is held to yoke levers which in turn 
are held to the second levers. The levers are thus connected successively 
to each other in a direction normal to the plane of the windshield, i.e., 
in a height direction of the rubber blade. In addition, the levers are 
coupled together so as to pivot freely on each joint portion of the 
levers. 
Since a single wiper blade is provided with a plurality of joint portions 
in this way, the levers are permitted to swing about their connections 
(i.e. the joint portions) even for a curvilinear windshield, so as to 
accommodate a curved surface of the windshield. The wiper blade, more 
precisely, the rubber blade is thereby allowed to firmly squeegee against 
the surface of the windshield. As a consequence, the windshield can be 
wiped completely without detracting from the wiping-ability of the rubber 
blade. 
Such a conventional tournament type wiper has the levers connected together 
in series in the height direction of the rubber blade, as previously 
described. Accordingly, the tournament type wiper can even cope with a 
windshield having a high curvature, with the levers being provided with a 
larger number of the connections (i.e., the joint portions), when desired. 
However, an increase in the number of the connections of the levers 
increases a projected area over a front surface of the wiper blade in a 
moving direction of a vehicle. Thus, air resistance (i.e., drag) and lift 
increase with the increase of speed of the vehicle. 
An increase in drag is undesirable. Consequently, it is necessary to 
increase the strength of the wiper and use a larger-sized wiper motor. In 
addition, an increase in lift leads to the lifting-off of the wiper blade, 
or rather the rubber blade. This precludes the rubber blade from wiping 
against the surface of the windshield in firm contact therewith. As a 
consequence, the rubber blade acquires an inferior wiping-ability. 
FIG. 13 illustrates a wiper blade 74 in which a first lever 70 is provided 
with a fin portion 72 in order to prevent the lifting-off of the wiper 
blade 74 due to the speed of a vehicle. This vehicle wiper is disclosed in 
Japanese Patent Application Laid-Open No. 62-61862. 
With continued reference to the wiper blade 74, FIG. 14 illustrates a 
cross-sectional view of a mounting portion 70A. The first lever 70 is 
formed with the mounting portion 70A to permit the first lever 70 to be 
mounted to a wiper arm. The mounting portion 70A includes a rear wall 70B 
in order to increase the rigidity of the mounting portion 70A. The 
mounting portion 70A thereby assumes a substantially rectangular-shaped 
cross-section. 
Accordingly, the rear wall 70B interferes with a flow of air which passes 
beneath the fin portion 72 in the direction of arrow W of FIG. 14. This 
interference adversely affects aerodynamic characteristics. 
Further, in United Kingdom Patent Application Laid-Open No. GB 2190834 A, 
the fin is disclosed, which is provided at the wiper blade in order to 
prevent the lifting-off of the wiper blade when the vehicle travels at 
high speeds. However, the torsional rigidity and the flexural rigidity of 
this wiper blade are insufficient. 
SUMMARY OF THE INVENTION 
In view of the above-described fact, an object of the present invention is 
to provide a vehicle wiper which can attain improved aerodynamic 
characteristics such that a wiper blade is allowed to wipe against a 
windshield when a vehicle travels at high speed. 
According to the present invention, the vehicle wiper is provided with a 
plurality of second levers and one first lever, the second levers 
supporting a rubber blade either with or without the use of a yoke lever, 
the first lever having the second levers pivotably connected to both end 
portions of the first lever while being pivotably held to a wiper arm at 
an intermediate portion of the first lever, the first lever includes: a 
first mounting portion having a pair of side walls defined at both sides 
of the first mounting portion which are spaced apart from each other in 
the longitudinal direction of the vehicle so as to permit the first lever 
to be mounted to the wiper arm; second mounting portions, each including a 
pair of side walls spaced apart from each other in the longitudinal 
direction of the vehicle, thereby assuming a substantially 
rectangular-shaped cross-section such that the second levers are mounted 
to the second mounting portions; a pair of fin portion member, defined 
respectively between the first mounting portion and each of the second 
mounting portions and extending from the first lever in a lower-forward 
direction of the vehicle so as to project beyond certain walls of the 
pairs of side walls of the first and second mounting portions, the certain 
walls being located in the forward direction of the vehicle; and, a 
twisted portion, combining the fin portion integrally with the first 
mounting portion as well as the second mounting portions. The fin portions 
have a rear edge portion formed at the top portion of each fin portion in 
relation to a vertical axis of the vehicle. As a result, when the vehicle 
travels at high speed, the wiper blade wipes the windshield without being 
lifted from the windshield. 
According to the present invention having the above structure, the first 
lever comprises the fin portions which have the rear edge portions formed 
at the top portions of the fin portions with respect to the vertical 
direction of the vehicle. This arrangement eliminates a rear wall which 
has been provided behind the fin portions in conventional wiper blade 
structures; the rear wall would impede an airflow which streams along the 
fin portions. The absence of the rear wall provides improved aerodynamic 
characteristics, which allows the wiper blade to squeegee against the 
windshield while the vehicle runs at high speed. In addition, the first 
lever comprises the twisted portion which combines the fin portions 
integrally with the first mounting member as well as the second mounting 
portions. The first lever thereby acquires sufficient rigidity. The fin 
portions, the first mounting portion, and the second mounting portions 
form the first lever. The first mounting portion has the pair of side 
walls defined at both sides thereof which are spaced apart from each other 
in the longitudinal direction of the vehicle so as to permit the first 
mounting portion to be mounted to the wiper arm. The second mounting 
portions have a substantially rectangular-shaped cross-section such that 
the second levers are mounted to the second mounting portions. 
In a vehicle wiper in accordance with another aspect of the present 
invention, the first lever is provided with the fin portions such that the 
rear edge portion of each fin portion is offset either in the forward 
direction or the rearward direction of the vehicle with respect to the 
center line which extends centrally through transverse axes of 
longitudinally extending intermediate portions of the first and second 
levers. 
According to the present invention having the above-described structure, 
the first lever is provided with the fin portions so that the rear edge 
portions of the fin portions are offset either in the forward direction or 
the rearward direction of the vehicle with respect to the center line that 
extends centrally through the transverse axes of the longitudinally 
extending intermediate portions of the first and second levers. This 
positioning of the rear edge portion provides a wide air-emitting passage 
between the first mounting portion and each of the second mounting 
portions, as seen from the top of the wiper blade, so as to emit air 
between the first lever and the second levers. Airflow thereby passes 
conveniently through the air-emitting passages defined therebetween, which 
provides improved aerodynamic characteristics. As a result, when the 
vehicle travels at high speed, the wiper blade wipes the windshield 
without being lifted from the windshield. 
In a vehicle wiper according to a further aspect of the present invention, 
the first mounting portion comprises a connecting fin portion. The 
connecting fin portion extends in the forward direction of the vehicle 
continuously from a bottom edge portion of one wall of the pair of side 
walls of the first mounting portion, the one of the pair of side walls 
being located in the forward direction of the vehicle. The connecting fin 
portion further extends therefrom in the lower-forward direction of the 
vehicle. 
According to the present invention having the above structure, the 
connecting fin portion extends in the forward direction of the vehicle 
continuously from the bottom edge portion of one wall of the pair of side 
walls of the first mounting portion, the one wall of the pair of side 
walls being located in the forward direction of the vehicle. The 
connecting fin portion further extends therefrom in the lower-forward 
direction of the vehicle. Air current flows along beneath the connecting 
fin portion of the first mounting member in relation to the vertical axis 
of the vehicle. Now, the connecting fin portion guides the air current 
into a path which extends through the underside of the rear wall of the 
first mounting portion. This reduces the occurrence of disturbed airflow 
caused by the rear wall of the first mounting portion. Such a smooth flow 
of air provides improved aerodynamic characteristics. As a consequence, 
when the vehicle runs at high speed, the wiper blade squeegees the 
windshield without being lifted from the windshield.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A vehicle wiper according to a first embodiment of the present invention 
will now be described with reference to FIG. 1 through FIG. 4. 
FIG. 1 illustrates a vehicle wiper 10 which includes a wiper arm 12 and a 
wiper blade 20. The wiper arm 12 further includes an arm head 14, an arm 
piece 16, and a retainer 18. The arm head 14 is fixed to an unillustrated 
pivot shaft which in turn is mounted to a vehicle body. The arm piece 16 
is connected to the arm head 14 so as to hold the wiper blade 20. (Details 
on the wiper blade 20 can be found in the next paragraph hereinbelow.) The 
retainer 18 connects the arm head 14 and the arm piece 16 together. In 
addition, there is an unillustrated arm spring disposed between the arm 
head 14 and the arm piece 16. The arm spring imparts a given compressive 
force to the wiper blade 20 so as to force the wiper blade 20 against a 
windshield 22. 
Next, the wiper blade 20 consists of a rubber blade 24 and a plurality of 
metallic levers for having the rubber blade 24 held to the metallic 
levers. The windshield 22 is squeegeed by the rubber blade 24 being held 
in contact with the surface of the windshield 22. 
A first lever 28 is formed by part of the above metallic levers which have 
the rubber blade 24 held to the metallic levers. The first lever 26 has a 
first mounting portion 27 defined at a longitudinally extending 
intermediate portion of the first lever 26. The first mounting portion 27 
is pivotably supported to one end portion of the arm piece 16 by a rivet 
28. 
FIG. 3 illustrates a cross-sectional view of the first mounting portion 27 
of the first lever 26. The first mounting portion 27 includes a front wall 
27A and a rear wall 27B, with an opening portion of the first mounting 
portion 27 facing the windshield 22 (i.e., in the downward direction of 
FIG. 3). Accordingly, the first mounting portion 27 has a substantially 
rectangular-shaped cross-section. The front wall 27A is provided with a 
connecting fin portion 31 at a bottom edge portion of the front wall 27A. 
The connecting fin portion 31 includes a horizontal portion 31A and a 
beveled portion 31B. The horizontal portion 31A extends in the forward 
direction of a vehicle continuously from the bottom edge portion of the 
front wall 27A. The beveled portion 31B extends in a lower-forward 
direction of the vehicle continuously from the horizontal portion 31A. 
As designated by arrows W1, W2, and W3 of FIG. 3, there are currents of air 
which separately flow along the connecting fin portion 31 of the first 
mounting portion 27. In particular, the air current W3, which flows along 
the underside of the connecting fin portion 31, is guided by the 
horizontal portion 31A into a path which extends through the underside of 
the rear wall 27B of the first mounting portion 27. 
Referring back to FIG. 1, the first lever 26 is formed with a pair of 
second mounting portions 29 at both end portions thereof in the 
longitudinal direction of the first lever 26. Each of the pair of second 
mounting portions 29 has a substantially rectangular-shaped cross-section, 
with an opening portion thereof being directed toward the windshield 22. 
The pair of second mounting portions 29 has a pair of second levers 32 
pivotably supported thereto by rivets 30. 
The first lever 26 further has a pair of fin portions 42 defined between 
the first mounting portion 27 and the pair of second mounting portions 29. 
The pair of fin portions 42 extends downwardly therefrom so as to project 
forwardly beyond the front wall 27A of the first mounting portion 27 as 
well as a pair of front walls 29A of the pair of second mounting portions 
29. The pair of fin portions 42 are combined integrally with: the first 
mounting portion 27 via a pair of twisted portions 44; and, the pair of 
second mounting portions 29 via a pair of twisted portions 45. FIG. 4 
shows a cross-sectional view of each of the pair of fin portions 42 of the 
first lever 26, in which the fin portion 42 slants upwardly at an angle 
ranging from zero to 90.degree. with respect to the horizontal plane of 
the fin portion 42. 
Referring to FIG. 2, each of the pair of fin portions 42 includes a rear 
edge portion 42A and an upper surface portion 42B. Each of the pair of 
second mounting portions 29 has an upper surface portion 29B which is 
integrally combined with the upper surface portion 42B of the fin portion 
42. Accordingly, the rear edge portion 42A extends from the upper surface 
portion 29B along the upper surface portion 42B. In addition, according to 
the present embodiment, a pair of rear edge portions 42A of the fin 
portions 42 is forwardly offset from the longidutinal axis or center line 
P (i.e., in the downward direction of FIG. 2), center line P extending 
centrally through the first lever 26 and the pair of second levers 32. 
A wide air-emitting passage 47 is thereby provided between the first 
mounting portion 27 and the pair of second mounting portions 29, as seen 
from the top of the wiper blade 20. As illustrated in FIG. 4, air is 
permitted to emit though the passage 47 which is defined between the first 
lever 26 and the second lever 32. 
Referring back to FIGS. 1 and 2, the first lever 26 includes a leading edge 
portion 26A in the longitudinal direction of the first lever 26. The 
leading edge portion 26A extends continuously between the pair of fin 
portions 42 and the connecting fin portion 31. With further reference to 
FIGS. 3 and 4, the leading edge portion 26A is bent in the forward 
direction of the vehicle in order to prevent burble from occurring when 
airflow strikes thereagainst. 
As shown in FIG. 1, the first lever 26 has the pair of second levers 32 
connected thereto at both end portions of the first lever 26. The pair of 
second levers 32 is formed with a pair of connecting portions 32A at 
opposite end portions thereof in the longitudinal direction of the pair of 
second levers 32. Each of the pair of connecting portions 32A has an 
opening portion facing the windshield 22, thereby forming a substantially 
rectangular-shaped cross-section. The pair of connecting portions 32A is 
provided with a pair of yoke levers 40 which is pivotably supported 
thereto via each rivet 38. The pair of yoke levers 40 is formed with a 
pair of holding portions 40A at opposite end portions thereof in the 
longitudinal direction of the pair of yoke levers 40. Each of the pair of 
yoke levers 40 has an opening portion directed toward the windshield 22, 
thereby assuming a substantially u-shaped cross-section. In this way, the 
wiper blade 20 is formed into a so-called tournament type rubber blade 
holder by the first lever 26, the pair of second levers 32, and the pair 
of yoke levers 40. 
Next, the operation of the present embodiment will be described. 
In the vehicle wiper 10 according to the present embodiment, the first 
lever 26 includes a pair of fin portions 42. Each of the pair of fin 
portions 42 has a rear edge portion 42A and an upper surface portion 42B. 
Each of the pair of second mounting portions 29 has an upper surface 
portion 29B. The upper surface portion 42B extends continuously from the 
upper surface portion 29B. Accordingly, the rear edge portion 42A extends 
from the upper surface portion 29B along the upper surface portion 42B. 
This configuration eliminates a rear wall 70B which is provided behind a 
fin portion 72 in conventional wiper blade structures, as illustrated in 
FIG. 14. The rear wall 70B interferes with air current W flowing along the 
fin portion 72. The absence of the rear wall 70B provides improved 
aerodynamic characteristics, as can be seen from FIG. 12. According to the 
drawing, lift and aerodynamic force achieved by the present embodiment 
(see the solid line of FIG. 12) is smaller than in a prior art example as 
indicated by the dotted line of FIG. 12, assuming that car velocity V is 
the same in both cases. Such improved aerodynamic characteristics permits 
the use of a smaller-sized wiper motor and allows the wiper blade 20 to 
squeegee the windshield 22 in firm contact therewith while the vehicle is 
operating at high speed. 
Another advantage of the vehicle wiper 10 according to the present 
embodiment is that a wide air-emitting passage 47 is provided between the 
first mounting portion 27 and the pair of second mounting portions 29, as 
seen from the top of the wiper blade 20. The passage 47 is permitted to 
emit air between the first lever 26 and the pair of second levers 32. To 
be specific, the pair of rear edge portions 42A of the fin portions 42 is 
forwardly offset from center line P which extends centrally through the 
first lever 25 and the pair of second levers 32. An airflow designated by 
arrow W4 of FIG. 4 thereby passes easily between the first lever 26 and 
the pair of second levers 32, which results in improved aerodynamic 
characteristics. As a result, while the vehicle travels at high speed, the 
wiper blade 20 is allowed to wipe the windshield 22 in contact therewith 
without being lifted from the windshield 22. 
The present embodiment offers a further advantage in which the first lever 
26 can acquire sufficient rigidity because the first lever 26 is formed 
with two pairs of twisted portions 44 and 45. One pair of twisted portions 
44 integrally combines the pair of fin portions 42 with the first mounting 
portion 27. The other pair of twisted portions 45 combines the pair of fin 
portions 42 integrally with the pair of second mounting portions 29. The 
first mounting portion 27 has the front wall 27A and the rear wall 27B 
defined at both sides thereof in the longitudinal direction of the 
vehicle, so as to allow the first mounting portion 27 be mounted to the 
wiper arm 12. The pair of second mounting portions 29 has a substantially 
rectangular-shaped cross-section such as to permit the pair of second 
levers 32 to be mounted to the pair of second mounting portions 29. 
A still further feature of the vehicle wiper 10 in accordance with the 
present embodiment is that the connecting fin portion 31 includes the 
horizontal portion 31A and the beveled portion 31B. The horizontal portion 
31A extends in the forward direction of the vehicle continuously from the 
bottom edge portion of the front wall 27A. The beveled portion 31B extends 
in the lower-forward direction of the vehicle continuously from the 
horizontal portion 31A. As designated by arrows W1, W2, and W3 of FIG. 3, 
there are air currents which separately flow along the connecting fin 
portion 31. In particular, the air current W3, which flows along the 
underside of the connecting fin portion 31, is guided by the horizontal 
portion 31A into a path which extends through the underside of the rear 
wall 27B of the first mounting portion 27. This shift in airflow W3 
reduces the occurrence of disturbed airflow which would otherwise be 
caused by the rear wall 27B of the first mounting portion 27. Such a 
smooth flow of air provides improved aerodynamic characteristics. The 
wiper blade 20 is thereby allowed to wipe against the windshield 22 
without being lifted therefrom when the vehicle runs at high speed. 
Note that the pair of rear edge portions 42A of the fin portions 42 may be 
offset rearward from center line P which extends through the first lever 
26 and the second lever 32, as illustrated in FIGS. 5A and 5B, as opposed 
to the present embodiment shown in FIG. 2 in which the pair of rear edge 
portions 42A are located in front of the same center line P. 
Alternatively, the pair of rear edge portions 42A may be coextensive with 
the same center line P. 
Furthermore, as illustrated in FIGS. 6A, 6B, and 6C, metallic portions of 
the first lever 26 may be limited to the first and second mounting 
portions 27 and 29. The rest of the first lever 26 may be made of a resin 
material, instead of metal in accordance with the present embodiment. In 
this variation, however, continuous-connecting portions of the first lever 
26 between the first mounting portion 27 and a pair of fin portions 41 are 
made thicker for reinforcement. Thus, the first and second mounting 
portions are formed of material having a higher rigidity than remaining 
portions of the first lever 26. In addition, as shown in FIG. 7, the pair 
of fin portions 41 may be formed with a pair of additional fin portions 
46. The pair of additional fin portions 46 is made of a resin material, 
and is disposed in front of the pair of second levers 32 in the forward 
direction of the vehicle. 
Furthermore, referring to FIG. 8, the leading edge portion 26A of the first 
lever 26 may be sheathed with a shock-absorbing material 50 in order to 
provide a smooth wipe of the windshield 22 if the fin portions 42 or 41 
interfere with the windshield 22. Alternatively, the leading edge portion 
26A may be bent in a direction shown in FIG. 9. These countermeasures 
provide increased safety against the fin portions 42 or 41 and the 
windshield 22. 
Note that the cross-sectional shape of the first lever 26 is not limited to 
the details according to the embodiment and attendant variations as 
previously described, but may be applicable to others as shown in FIGS. 
10A through 10G. Furthermore, the cross-sectional shapes of the second 
lever 32 and the yoke lever 40 are not limited to those according to the 
above-described embodiment and attendant variations, but may be formed 
into those shown in FIGS. 11A and 11B. 
While the present invention has been shown and described with reference to 
the preferred embodiment and associated variations thereof, it is to be 
understood that numerous changes and modifications may be made without 
departing from the spirit or scope of the following claims.