Vehicle wiper

Abstract: A vehicle wiper (10) provided with a plurality of second levers (32) and one first lever (26), the second levers (32) supporting a rubber blade (24) either with or without the use of a yoke lever, the first lever (26) having the second levers (32) pivotably connected to both end portions (26B) of the first lever (26) while being pivotably held (28) to a wiper arm (16) at an intermediate portion of the first lever (26). The first lever includes a first mounting member (27) and a second mounting member (29), the former having a pair of side walls so as to permit the first lever (26) to be mounted to the wiper arm (16). The second mounting member (29) includes a pair of side walls such that the second levers (32) are mounted to the second mounting member (32). The first lever (26) further includes a fin member (42) defined between the first mounting member (27) and the second mounting member (29), the fin member (42) extending therefrom in the lower-forward direction of the vehicle so as to project beyond ones of the pairs of side walls of the first and second mounting members, the ones of the pairs of side walls being located in the forward direction of the vehicle. The fin member has a rear edge portion formed at the top portion of the fin member with respect to a vertical axis of the vehicle. Furthermore, the first lever (26) includes a twisted portion (44) which combines the fin member with the first mounting member (27) and the second mounting member (29).

Description: The present invention relates to a vehicle wiper according to the preamble of claim 1. From the document GB-A-2 190 834 a generic vehicle wiper is known. This vehicle wiper is constructed such that a main joke is formed by a plate bended along a line to form on the one side thereof an elongated fin member, and on the other side thereof first and second mounting members. This other side of the plate has cut back portions as standing between the first and second mounting members, wherein the mounting members are connected by connecting portions. The connecting portions being part of the fin member. At present, 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) 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 pivot ably 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. 12 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 JP-A-61862/87. With continued reference to the wiper blade 74, FIG. 13 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. 13. This interference adversely affects aerodynamic characteristics. Further, in United Kingdom Patent Application Laid-Open GB-A-2190834, 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. The 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. The object is achieved by means of the combination of the features defined in claim 1. Prefered embodiments are recited in claims 2 to 10. The arrangement according to the invention eliminates the rear wall which has been provided behind the fin member in conventional wiper blade structures; the rear wall would impede an airflow which streams along the fin member. 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 a twisted portion which combines the fin member integrally with a first mounting member as well as the a second mounting member. The first lever thereby acquires sufficient rigidity. Furthermore, the inventive positioning of a rear edge portion of the fin member provides a wide air-emitting passage between the first mounting member and the second mounting member, 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 passage 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. According to an embodiment of the present invention, a connecting fin member extends in the forward direction transverse to a longitudinal direction of the wiper blade continuously from the bottom edge portion of one of the pair of side walls of the first mounting member, the one of the pair of side walls being located in the forward direction of the vehicle. The connecting fin member further extends therefrom in the lower-forward direction transverse to a longitudinal direction of the wiper blade. Air current flows along beneath the connecting fin member of the first mounting member. Now, the connecting fin member guides the air current into a path which extends through the underside of the rear wall of the first mounting member. This reduces the occurrence of disturbed airflow caused by the rear wall of the first mounting member. 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. In the following the invention is further illustrated by embodiments with reference to the enclosed drawings. FIG. 1 is a perspective view, illustrating a vehicle wiper in accordance with a first embodiment of the present invention. A part of the vehicle wiper is shown in phantom; FIG. 2 is a plan view, illustrating main components of the vehicle wiper in accordance with the first embodiment. A part of the vehicle wiper is shown in phantom; FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2; FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2; FIG. 5A is a perspective view, showing a first lever of a vehicle wiper according to a modification of the first embodiment; FIG. 5B is a cross-sectional view taken along line B-B of FIG. 5A; FIG. 5C is a cross-sectional view taken along line C-C of FIG. 5A; FIG. 6 is a perspective view, illustrating a first lever of a vehicle wiper according to another modification of the first embodiment; FIG. 7 is a cross-sectional view, illustrating a first lever of a vehicle wiper according to a further variation of the first embodiment; FIG. 8 is a cross-sectional view, showing a first lever of a vehicle wiper according to a still further variation of the first embodiment; FIGS. 9A through 9G are cross-sectional views, illustrating first levers of vehicle wipers in accordance with still further variations of the first embodiment; FIGS. 10A and 10B are cross-sectional views, showing wiper blades of vehicle wipers according to even further variations of the first embodiment; FIG. 11 is a graphical illustration, indicating lift and aerodynamic characteristics of a wiper blade according to the first embodiment and those of a conventional wiper blade; FIG. 12 is a plan view, illustrating a wiper blade of a conventional vehicle wiper; and, FIG. 13 is a cross-sectional view taken along line 13-13 of FIG. 12. 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 26 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 transverse to the longitudinal direction of the wiper blade 20 continuously from the bottom edge portion of the front wall 27A. The beveled portion 31B extends in a lower-forward direction transverse to the longitudinal direction of the wiper blade 20 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° 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 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 through 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 transverse to the longitudinal direction of the wiper blade 20 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 rectangular-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. 11. According to the drawing, lift and aerodynamic force achieved by the present embodiment (see the solid line of FIG. 11) is smaller than in a prior art example as indicated by the dotted line of FIG. 11, 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 26 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 transverse to the longitudinal direction of the wiper blade 20 continuously from the bottom edge portion of the front wall 27A. The beveled portion 31B extends in the lower-forward direction transverse to the longitudinal direction of the wiper blade 20 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. Furthermore, as illustrated in FIGS. 5A, 5B, and 5C, 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. In addition, as shown in FIG. 6, 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 transverse to the longitudinal direction of the wiper blade 20. Furthermore, referring to FIG. 7, 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. 8. 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. 9A through 9G. 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. 10A and 10B.

Claims: A vehicle wiper provided with a plurality of second levers (32) and one first lever (26), said second levers supporting a blade (24) through one selection between the use of a yoke lever and without the use thereof, said first lever (26) having said second levers pivotably connected to both end portions thereof, said vehicle wiper comprising: a first mounting member (27), which constitutes said first lever (26) and has a pair of side walls (27A, 27B) defined at both sides of said first mounting member which are spaced apart from each other in a forward direction transverse to a longitudinal direction of a wiper blade (20); a second mounting member (29), which also constitutes said first lever (26) and includes a pair of side walls spaced apart from each other in said forward direction, thereby assuming a substantially rectangular-shaped cross-section such that said second levers (32) are mounted to said second mounting member; and a fin member (42), which also constitutes said first lever (26), said fin member being defined between said first mounting member (27) and said second mounting member (29), said fin member (42) having a rear edge portion (42A) formed at the top portion (42B) of said fin member (42), thereby preventing said wiper blade (20) from being lifted from a windshield so as to wipe against said windshield when said vehicle travels at high speed, wherein said fin member (42) has an inclined surface which extends from said first lever in a lower-forward direction so as to project beyond front walls (27A, 29A) of said first and second mounting members (27, 29), characterized by twisted portions (44, 45) between said first and second mounting members (27, 29) of said first lever (26), such that the rear edge portion (42A) of the fin member (42) is arranged further forward with respect to a center line (P) which extends through the center of said first and second lever (26, 32), the special shape and arrangement of said fin member (42) and said twisted portions (44, 45) thus providing an air-emitting passage (47) defined between said first and second levers (26, 32) so as to emit air between said first and second levers. A vehicle wiper according to claim 1, characterized in that said first mounting member (27) comprises a connecting fin member (31) which extends in said forward direction continuously from a bottom edge portion of one of said pair of side walls (27A, 27B) of said first mounting member, said one of said pair of side walls (27A, 27B) being located in said forward direction, said connecting fin member (31)further extending therefrom in the lower-forward direction. A vehicle wiper according to claim 1 or 2, characterized in that said rear edge portion (42A) of said fin member (42) is offset in said forward direction with respect to a center line (P) which passes through a transverse direction central point of said second levers (32). A vehicle wiper according to claim 2 or 3, characterized in that said connecting fin member (31) and said fin member (42) have edge portions (26A) located in the forward direction of said vehicle, said edge portions being integrally combined into a leading edge portion (26A) which is bent in said forward direction so as to prevent airflow burble. A vehicle wiper according to claim 1 or 3, characterized in that said first mounting member (27) and said second mounting member (29) are formed of materials of higher rigidity than other members. A vehicle wiper according to claim 1 or 3, characterized in that said fin member (42) comprises an additional fin member (46) which extends in the longitudinal direction of said wiper blade from each end portion of said fin member located in the logitudinal direction of said wiper blade (20), said additional fin member being positioned in front of each of said second levers (32) in said forward direction. A vehicle wiper according to claim 4, characterized in that said leading edge portion (26A) is sheathed with a shock-absorbing material (50). A vehicle wiper according to claim 4, characterized in that said leading edge portion (26A) is curved upwardly or downwardly from said forward direction. A vehicle wiper according to one of the claims 2, 3 and 5, characterized in that said first mounting member (27) and said second mounting member (29) are formed of metal, with the remaining portions thereof being made of resin materials. A vehicle wiper according to one of the claims 2, 3 and 6, characterized in that said fin member (42) is formed of a resin material.

Inventors: HIRAKU YAOKI, OHMURA EIICHI, OKUYA SATORU, HIRAKU, YAOKI, OHMURA, EIICHI, OKUYA, SATORU
Applicants: ASMO CO LTD, TOYOTA MOTOR CO LTD, ASMO CO., LTD., TOYOTA JIDOSHA KABUSHIKI KAISHA
Application year: 1993
Main classification: B60S1
IPC codes: B60S1