WINDSHIELD WIPER

Abstract: A windshield wiper including an arm head (1) connected to a driving motor and being reciprocatingly and rotatably connected to a pivot shaft (5), and a wiper arm supported on the arm head and being connected to a wiper blade. The arm head comprises a first head portion (2) reciprocatingly and rotatably supported on the pivot shaft, and a second head portion (3) connected to the first head portion and being rotatable around an axis which is generally perpendicular to the axis of the pivot shaft, and there is provided a mechanism (10-13) for rotating the second head portion with respect to the first head portion in response to the rotation of the first head portion around the pivot shaft.

Description: The present invention relates to a windshield wiper and according to the pre-characterising part of claim 1. There have been various windshield wipers proposed for cleaning windshields of automobiles, which usually comprise an arm head reciprocatingly rotatable around a pivot shaft, a wiper arm pivotally connected to the arm head and reciprocatingly movable through a predetermined wiping angle, a wiper blade supported on the wiper arm and contacting the surface of the windshield, and an arm spring acting between the arm head and the wiper arm to bias the wiper blade against the surface of the windshield. Recent automobiles have curved windshields for reducing aerodynamic drag and improving the appearance, which inevitably results in a change in the angle between the surface of the windshield and a rubber blade of the windshield wiper or a change in the contacting angle during the wiping stroke of the wiper. Particularly, when the windshield is sharply curved, the wiper will not act satisfactorily. Usually it is considered that the allowance range of the contacting angle is + 5 degrees. It is known from FR-A-2 488 558 to provide a windshield wiper according to the pre-characterising part of claim 1. In FR-A-2 488 558 the rotating means comprises a ball and socket joint, a first head portion located at the top of the pivot shaft forming the socket, a second head portion engaging the socket to enable said second head portion to rotate about an axis generally perpendicular to the axis of the pivot shaft. According to the invention in a windshield wiper according to the pre-characterising part of claim 1, the rotating means comprises a worm operatively connected to said first head portion, a worm gear fixed to said second head portion and engaging said worm for rotating to rotate said second head portion about said second rotational axis when said worm rotates, and a linkage mechanism operatively connected between said worm and said stationary mounting plate for selectively rotating said worm as said arm head rotates about the rotational axis of said pivot shaft, said linkage mechanism comprising a first link having one end fixedly connected to said worm, and a second link having one end pivotably connected to said stationary mounting plate and the other end pivotably connected to the other end of said first link. Our invention is particularly adapted to a windshield wiper having a substantially constant contacting angle on a sharply curved surface windshield. Further objects and effects of the invention will become apparent from the following detailed description in conjunction with the drawings, in which:- Figure 1 is a perspective exploded view of a windshield wiper according to the invention; Figure 2 is a schematic diagram showing the relationship between the rubber blade and the surface of windshield, according to the invention; Figure 3 is a view similar to Figure 2 but showing the relationship according to the prior art, and Figure 4 is a graph showing the relationship between the rotation of the wiper arm according to the invention with respect to the rotation of the arm head. An embodiment according to the invention is shown in Figure 1, and comprises an arm head 1 consisting of a first head portion 2 and a second head portion 3. A wiper blade (not shown) is mounted on the tip end portion (not shown) of the second head portion 3. The arm head 1 is connected to a pivot shaft 5 and rotates reciprocatingly around an axis 4-4. The second head portion 3 is rotatable relative to the first head portion 2 through a shaft 7 extending within a bore 6 formed in the first head portion 2, and the axis of the shaft 7 (which is referred to as the longitudinal axis of the arm head) is generally perpendicular to the axis 4-4. When the second head portion 3 rotates, the wiper blade mounted on the second head portion rotates relative to the surface of the windshield, whereby the contacting angle of the rubber blade changes. To rotate the second head portion 3 in response to the rotational movement of the arm head 1 around the axis 4-4, a link arm 24 is secured to the worm 14 and is pivotally connected to a link arm 23 which is pivotally mounted on the stationary mounting plate 10. In the embodiment, a bore 15 open at the bottom surface of the first head portion 2 rotatably supports a shaft portion of the worm 14, and the worm 14 is retained by a pin 16 and a nut 17. The axis of the worm 14 is parallel to the axis of the pivot shaft 5. The shaft portion of the worm 14 meshingly engages with a worm gear 19. The worm gear 19 is fixed to an extension 18 of the shaft 7 of the second head portion 3 by means of a screw. When the first head portion 2 reciprocatingly rotates about the shaft 5, the worm 14 rotates since the link arm 24 is connected to the link arm 23. Due to the engagement between the worm 14 and the worm gear 19, the second head portion 3 rotates relative to the first head portion 2 so that the contacting angle of the rubber blade with respect to the surface of the windshield changes. In the embodiment, the second head portion 3 rotates uniformly during the entire range of rotation of the first head portion 2. The worm 14 and the worm gear 19 act to prevent incidental rotation of the second head portion 3. Shown at 22 in Figure 1 are mounting holes in the mounting plate 10. The embodiment had a simple construction, but it is possible to change the relationship between the rotation of the pivot shaft 5 and that of the second head portion 3 as desired. Figures 2 and 3 show the relationship between the rubber blade and the surface of the windshield according to the invention (Figure 2) and prior art (Figure 3), in which the surface of the windshield is shown at 40, and 41 and 41' show rubber blade at two different positions. Figure 4 shows one example of the relationship between the rotation of the pivot shaft and that of the second head portion according to the invention. As described heretofore, according to the invention, it is possible to change the contacting angle of the rubber blade during the reciprocatingly rotating motion of the wiper arm. Thus, it is possible to improve the cleaning characteristics of the wiper and to prevent excessive wear of the rubber blade.

Claims: A windshield wiper comprising: a rotable pivot shaft (5) having a rotational axis (4-4); an arm head (1) mounted to said pivot shaft (5) for reciprocatingly rotating about the rotational axis (4-4) thereof, said arm head (1) comprising a first head portion (2) connected to said pivot shaft (5), a second head portion (3) rotatably mounted to said first head portion (2) about a second rotational axis extending generally perpendicular to the axis of rotation of said pivot shaft (5), and rotating means for rotating said second head portion (3) about said second rotational axis, and a stationary mounting plate (10), characterised in that, said rotating means comprises a worm (14) operatively connected to said first head portion (2), a worm gear (19) fixed to said second head portion (3) and engaging said worm (14) for rotating to rotate said second head portion (3) about said second rotational axis when said worm (14) rotates, and a linkage mechanism operatively connected between said worm (14) and said stationary mounting plate (10) for selectively rotating said worm (14) as said arm head (1) rotates about the rotational axis (4-4) of said pivot shaft (5), said linkage mechanism comprising a first link (24) having one end fixedly connected to said worm (14), and a second link (23) having one end pivotably connected to said stationary mounting plate (10) and the other end pivotably connected to the other end of said first link (24).

Inventors: ARAI, MASARU, SAITA, ITSURO
Applicants: NIPPON WIPER BLADE CO., LTD.
Application year: 1987
Main classification: B60S1
IPC codes: B60S1