PERFECTED WINDSHIELD WIPER

Abstract: A windshield wiper (1) on which the conventional blade carrier member and respective articulated joint have been eliminated. The windshield wiper, in fact, consists of a connecting element (4) for connection to the control pin; a wiper blade (9) formed from elastomeric material; and an arm (7) secured radially to the connecting element by means of a conventional articulated device and defined by a streamlined structure having a U-shaped section and longitudinally matching the mean curvature of the wind­ shield (3). Respective elastic means (18) inside the structure (7) secure the wiper blade to the same, in such a manner as to press the blade against the windshield and, at the same time, allow varying longitudinal flexure of the blade at various points along the same.

Description: The present invention relates to a perfected windshield wiper suitable for fitment to vehicles and, in particular, designed to ensure optimum wiping of the windshield under all atmospheric conditions and at any vehicle speed, even in the presence of a single wiper blade. The wiping efficiency of a windshield wiper is known to depend on the pressure exerted by the wiper blade on the glazing surface of the windshield as the blade swings back and forth. On known windshield wipers, both single- and conventional two-blade types, the wiper blade, formed from flexible material such as rubber, is carried on a complex blade carrier member which, in turn, is carried via an articulated joint on a rigid arm connected, in radially-projecting manner and by means of a further articulated device, to a cap-shaped connecting element mounted angularly rigid with a control pin. Reciprocal rotation of the said pin, which is controlled by a motor, activates the wiper by swinging the arm and respective blade through a given arc. Correct pressure of the wiper blade over the entire wiped area should be guaranteed partly by the articulated device between the arm and connecting element, for which purpose it is provided with a spring, and partly by the design of the blade carrier member, which should provide for a certain amount of blade distortion for adapting to the varying curvature of the windshield at various points along the wipe trajectory. Unfortunately, and on single-blade wipers, in particular, which feature a larger-size blade than conventional two-blade types, the above provisions are insufficient for ensuring correct pressure of the wiper blade and, consequently, optimum wiping performance, over the entire wiped area. Furthermore, the complex, cumbersome assembly consisting of the blade carrier member, articulated joint and arm, creates numerous streamlining problems, which may result in noise, an increase in the drag coefficient of the vehicle, and worse still, partial or total detachment of the wiper blade from the windshield, thus reducing or removing all contact pressure between the blade and windshield, and, consequently, impairing both wiping performance and visibility. The aim of the present invention is to provide a windshield wiper designed to overcome the aforementioned drawbacks, i.e. a wiper of straightforward, compact design, that is easy and cheap to manufacture, and provides for both optimum wiping performance and streamlining. With this aim in view, according to the present invention, there is provided a windshield wiper as defined in Claim 1. Further developments in line with claim 1 are referred to in the dependent claims. Two non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawing, in which : Fig.s 1 and 2 show partially-sectioned longitudinal views of two embodiments of the windshield wiper according to the present invention; Fig.3 shows a cross section of the Fig.2 wiper. Number 1 in Fig.s 2 and 3 indicates a windshield wiper, in particular, a single-blade wiper, for wiping the outer surface 2 of a windshield 3 of any curvature, or the glazing surface of a backlight or headlight on a known vehicle (not shown), e.g. an automobile. Wiper 1 comprising a known cap-shaped connecting element 4 designed to fit angularly integral with a rotary pin 5 controlling wiper 1, supported on body 6 of the said vehicle (not shown), and powered by a known motor (not shown); an arm 7 carried in radially-projecting manner on the said connecting element 4 and connected angularly integral with the same by means of an articulated device 8; and a flexible wiper blade 9 formed in one piece from elastomeric material, e.g. rubber, and mounted integral with arm 7. Blade 9 is of known type, and formed so as to cooperated in sliding manner with, and wipe, the said surface 2 by moving over the same at a given pressure. Such pressure is provided by arm 7, partly by means of articulated joint 8, which may be provided in known manner with a spring (not shown) and is designed to enable rotation of end 10 of arm 7, adjacent to connecting element 4, about an axis perpendicular to the axis of rotation of pin 5 and substantially parallel with the plane of windshield 3, and partly, according to the present invention, by virtue of the special design of arm 7 itself. For the sake of simplicity, no further description will be given of articulated device 8, which is a commonly known type, substantially identical to those employed on known windshield wipers currently available on the market. According to the present invention, instead of being carried on a blade carrier member connected to arm 7, as on known windshield wipers, blade 9 is carried directly on arm 7, which consists of a rigid, streamlined structure of such a length as to fully accommodate blade 9, and terminating, at the connecting element 4 end, in end 10 incorporated inside articulated joint 8, and, at the opposite end, in a longitudinally-tapered cap 11 defining the end of structure 7 opposite the said end 10. Streamlined structure or arm 7 may be formed from bent sheet metal, or molded from synthetic plastic, and is shaped longitudinally so as to substantially match the mean curvature of surface 2. As, for reasons of streamlining, the said surface 2 is usually curved, structure 7 is also curved and presents, at each longitudinal point, a concentric radius of curvature slightly greater than that of surface 2. The cross section of structure 7, on the other hand, is substantially constant, and substantially in the form of an inverted U with its open end facing downwards in the direction of windshield 3. Blade 9 is housed longitudinally over its entire length inside structure or arm 7, and is arranged in line with structure 7 in an open bottom portion 12 of the same, with its bottom longitudinal wiping edge 14 projecting downwards beyond portion 12 and in the direction of windshield 3. The top longitudinal edge 15 of flexible blade 9, opposite the said edge 14 and preferably having a T-shaped section, is connected with structure or arm 7 so as to form a single unit therewith via elastic means 18 housed inside structure 7, between a bottom wall 19 of the same and blade 9. The said elastic means are defined by a number of flexible V-shaped bows 18 arranged side by side, preferably singly, in a row along the entire length of structure 7, with their respective opposite ends 20 arranged adjacent to one another and secured integral with edge 15, and with a respective center line portion 21, at the tip of the V defined by each bow 18, hinged to structure 7 in such a manner as to enable bows 18 to rock about respective axes parallel with each other and with the rotation axis of articulated device 8, and all lying crosswise in relation to the longitudinal axis of structure or arm 7. In more detail, the said bows 18 present, on the said center line portion 21, respective opposed transverse projecting pins 22 engaged in idle manner inside respective pairs of coaxial transverse holes 23 formed through respective side walls 24 of structure 7. In the embodiment shown in Fig.s 2 and 3, each of the said bows 18 consists of a single flexible element formed from plastic or spring steel and shaped in the form of an inverted V, the center line portion 21 of which is substantially omega-shaped with integral laterally-projecting pins 22, which click inside lateral holes or seats 23, crosswise in relation to the axis of structure 7. Cap 11 is defined outwards by a curved surface, and is connected in rocking manner to the rest of structure 7 by pivoting on pins 22 of adjacent bow 18 which, numbered 18a in Fig.2, may be asymmetrical in relation to portion 21, depending on the length of cap 11. Cap 11 is thus free to rock, together with element 18a, in relation to the rest of structure 7, so as to adapt its position to the local curvature of windshield 3. According to the present invention, bows 18 are formed from materials having different elastic properties, or in slightly different shapes or sections, so as to present varying grades of rigidity. Flexible blade 9 is thus secured to rigid structure 7 by restraints differing in rigidity at various points on the structure and consequently also on windscreen 3, so as to produce a flexible connection varying in rigidity at various points between blade 9 and arm 7, and designed to resist, with given force, any displacement of blade 9 inwards of structure 7 (which results in compression and consequent springback of bows 18), while at the same time permitting varying longitudinal flexure of blade 9 at various points along the same, for enabling the blade contour to adapt continuously to the curvature of surface 2, even in the presence of continuous random variations in the same. Finally, for preventing lift-off of blade 9 at high vehicle speeds, the cross-section of the streamlined structure defining arm 7 presents opposite longitundinal edges 30 tapering outwards in thickness, curving away from each other, and located a given, relatively small distance from edge 14, so as to skim surface 2. In actual use, arm 7, in the idle position against one side of windshield 3, maintains the required contact pressure between edge 14 and surface 2 by virtue of the known performance of articulated joint 8. Reciprocal rotation of pin 5 causes arm 7 to move parallel with windshield 3, thus causing edge 14 to slide over and to wipe surface 2. During such displacement, rocking bows 18 enable flexible blade 9 to adapt to any variations in the curvature of windshield 3 by allowing it to make differential adjustment to its own curvature at various points along its length, thus maintaining, at each point on surface 2, the correct contact pressure imposed by articulated joint 8 between surface 2 and edge 14, and ensuring optimum wiping of windshield 3. Streamlining of arm 7 and installation of blade 9 inside the same reduce or eliminate aerodynamic disturbance, thus preventing noise or whistling at high vehicle speeds. Furthermore, the shape of edges 30 provides for effective downflow for maintaining blade grip on the windshield and preventing lift-off of the blade under all driving conditions. Finally, streamlined structure 7 also provides for effective removal of large quantities of packed snow off windshield 3. Fig.1 shows a windshield wiper 1a identical to wiper 1 except for the design of bows 18. For the sake of simplicity, components or details similar or identical to those already described will be referred to using the same numbering system. Each of bows 18 on windshield wiper 1a consists of a pair of oblique arms 32 having a first end 33 secured integral with blade 9 and a second opposite end 34 pivoting on a common pin 22 fitted crosswise inside structure 7; and a spring 35 designed to force arms 32 towards each other by rotating respective ends 34 pivoting on pin 22. By regulating the rigidity of spring 35, the rigidity of bow 18 as a whole may be regulated to produce the same effect already described in connection with windshield wiper 1. Operation of wiper 1a is also identical to that of wiper 1. The advantages of the present invention will be clear from the foregoing description. In addition to providing for a windshield wiper involving practically no aerodynamic disturbance and capable of effectively wiping glazing surfaces presenting random variations in curvature, it is also cheap to produce, by virtue of consisting of a small number of component parts as compared with known windshield wipers. Besides being employed singly, the windshield wiper according to the present invention may, of course, be employed in conjunction with a second symmetrical wiper activated by a second control pin, thus enabling the advantages of the present invention to be extended also to two-blade windshield wipers.

Claims: A windshield wiper (1, 1a) comprising a cap-shaped connecting element (4) mounted angularly integral with a rotary pin (5) controlling the said wiper; an arm (7) carried in radially-projecting manner on the said connecting element (4) and connected angularly rigid with the same (4) by means of an articulated device (8); and a flexible wiper blade (9) carried by the said arm (7) and designed to cooperate in sliding manner with the outer surface of the windshield (3); characterised by the fact that the said arm consists of a hollow, rigid, streamlined structure (7) which is curved and presents, at each longitudinal point, a concentric radius of curvature slightly greater than that of the outer surface (2) of the windshield (3), which presents a substantially U-shaped cross-section, and longitudinally houses the said wiper blade (9) over its entire length; the said wiper blade (9) being arranged in an open bottom portion (12) of the said streamlined structure, with its longitudinal wiping edge (14) projecting downwards from the said streamlined structure in the direction of the said windshield; the said windshield wiper also comprising elastic means (18, 18a) housed inside the said streamlined structure (7) and mechanically connecting the same to the said wiper blade (9); the said elastic means urging with a predetermined force the said wiper blade (9) outwards of the said streamlined structure (7), and being constrained in such a manner as to allow the wiper blade to assume different curvatures at various points along the same. A windshield wiper as claimed in Claim 1, characterised by the fact that the said elastic means comprise a number of flexible V-shaped bows (18, 18a) arranged side by side in a row over the entire length of the said streamlined structure (7), with their respective opposite ends (20, 33) adjacent to one another; and said bows (18, 18a) being hinged, along the center line, to the said streamlined structure (7) so as to rock about respective axes parallel with one another and all located crosswise in relation to the longitudinal axis of the said arm (7). A windshield wiper as claimed in Claim 2, characterised by the fact that the said articulated device (8) is designed to enable the end of the said arm (7) adjacent to the said connecting element (4) to rotate about an axis perpendicular to the axis of rotation of the said control pin (5) and substantially parallel with the plane of the said windshield (3). A windshield wiper as claimed in Claim 3, characterised by the fact that the said opposite ends (20, 33) of the said bows (18, 18a) are secured integral with the top edge (15) of the said wiper blade (9), opposite the said wiping edge (14) of the same; and the center line of the said bows (18, 18a) coincides with the tip of the V defined by each said bow (18, 18a), and presents respective opposite transverse pins (22) engaged inside respective pairs of coaxial holes (23) formed through respective side walls (24) on the said streamlined structure (7), so as to rock about axes parallel with the axis of rotation of the said articulated device (8). A windshield wiper as claimed in one of the foregoing Claims from 2 to 4, characterised by the fact that each said blow (18) consists of a pair of oblique arms (32) having a first end (33) secured integral with the said wiper blade (9) and a second opposite end (34) hinged at a common point (22) to the said streamlined structure (7); and a spring (35) designed to force the said two arms (32) towards each other by rotating the said opposite ends (34) pivoting in common. A windshield wiper as claimed in one of the foregoing Claims from 2 to 4, characterised by the fact that each said bow (18) consists of a single flexible element substantially in the form of an inverted V having its tip on a center line portion (21) of the said element; said center line portion (21) being substantially omega-shaped and having a pair of opposed laterally-projecting pins (22) designed to click inside respective lateral seats (23) formed through the said streamlined structure (7) and crosswise in relation to the axis of the same. A windshield wiper as claimed in one of the foregoing Claims, characterised by the fact that the said streamlined structure comprises a longitudinally-tapered cap (11) defining a first end of the said streamlined structure (7) opposite a second end of the same adjacent to the said articulated device (8); the said cap (11) being hinged to the rest of the said streamlined structure (7) coaxially with the rocking axis of a first (18a) of the said bows, adjacent to the said cap (11), so as to rock together with the same. A windshield wiper as claimed in one of the foregoing Claims, characterised by the fact that the cross section of the said streamlined structure (7) presents opposite longitudinal edges (30) tapering outwards in thickness, curving away from each other, and located a given, relatively small distance from the said wiping edge (14) of the said blade (9), so as to skim, in use, the said outer surface (2) of the said windshield (3). A windshield wiper as claimed in one of the foregoing Claims, characterised by the fact that the rigidity of the said elastic means (18) varies at various points on the said wiper blade (9).

Inventors: GRASSINI, OSVALDO
Applicants: FIAT AUTO S.P.A.
Application year: 1988
Main classification: B60S1
IPC codes: B60S1