Abstract:
A wiper apparatus for motor vehicle windshields is proposed, said apparatus being provided with a driven wiper arm located on the motor vehicle body and movable between reversing positions, on whose free end is fixed one side of a joint pin whose axis extends transverse to the longitudinal axis of the wiper arm and essentially in the direction of movement of the wiper arm. On the joint pin is lodged a wiper blade capable of swinging about the joint axis, the wiper apparatus having means for securing the wiper blade on the joint pin. A particularly cost-effective wiper apparatus is obtained when the securing means for the wiper blade are disposed on the wiper arm and on the side of the wiper blade facing away from said arm cooperate with a stop located on the wiper blade side.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a wiper apparatus. In a known wiper of this kind (DE 16 55 41 0 A1), the wiper arm and the wiper blade are disposed next to each other as viewed in the direction of the windshield to be wiped and one after the other as seen in the working direction of the wiper apparatus. In this manner, it is possible to achieve a lower overall height for the wiper apparatus than can be done for wipers in which the wiper arm is located over the wiper blade (DE 15 05 397 A1). The lower overall height of the wiper apparatus of this type is advantageous in terms of the lift-off of the wiper blade from the windshield, particularly at high travel velocities. 
     To ensure that the wiper blade is securely fastened by the joint pin during the wiping operation, in the known wiper arrangement the joint pin, which is disposed laterally on the wiper arm, is provided in its center portion with a ring groove into which, after the wiper blade is mounted on the joint pin, a leaf spring fits at one end, said leaf spring being capable of being deflected by a force and, together with the ring groove side walls, of securely fastening the wiper blade on the wiper arm. The arrangement and configuration of such securing means is cost-intensive because, on the one hand, the joint pin must be provided with a ring groove and, on the other, when the wiper blade is replaced, the new wiper blade must be provided with an appropriate leaf spring. 
     In another known wiper apparatus (DE 26 40 399 A1), the joint pin and the securing means formed by a hinged bracket are disposed on the same structural component of the wiper apparatus. Because this component is the wiper blade, however, when said blade has to be replaced, both the joint pin and the hinged bracket are lost. 
     SUMMARY OF THE INVENTION 
     In the wiper apparatus according to the invention, both the securing means and the joint pin are retained when the wiper blade is replaced. The securing means on the wiper blade side—namely the stop—can be formed by the corresponding side cheek of the wiper blade which is always present and which faces away from the wiper arm. This side cheek does not need to have a special configuration. 
     A wiper apparatus of particularly low design and thus flow-promoting is obtained when the wiper blade has a strip-shaped, elongated carrying element, made of an elastic material, for a wiping strip that comes in contact with the windshield to be wiped, on whose strip surface which faces away from the windshield is disposed a coupling part belonging to a connecting device and having a bearing recess for the joint pin. 
     In the configuration of the invention, the securing means of the wiper arm are formed by support regions which in the wiping direction are disposed at a distance from each other and are oriented toward each other, and between which are disposed matching regions of the wiper blade, said matching regions facing away from one another. A cost-effective realization of the inventive idea is attained in this manner. 
     A particularly robust and thus reliably operating wiper apparatus is obtained when one support region is disposed on a swiveling lever of the wiper arm and the swiveling lever has a shoulder which projects out in the direction of the joint axis and across the wiper blade and at the free end of which is disposed a leg facing the windshield, the side of said leg facing the swiveling lever forming the other support region. 
     To limit the length of the wiper blade to the required size, the distance from the free end of the wiper arm to the joint axis is smaller than the distance from the free end of the wiper arm to the shoulder. 
     According to a further development of the invention, viewed in the longitudinal direction the bearing bore is disposed in the coupling part near one end of the same and, furthermore, the coupling part is lower, at least in the region of the shoulder and relative to the carrying element, than in the region of the bearing bore. In other words, the shoulder can be located where the coupling part is lower so that, as a result of the arrangement of the shoulder in the transverse region, the overall height does not need to be increased. The stability of the coupling part in the region of the highly stressed bearing bore is thereby not impaired. 
     Advantageously, this low region of the coupling part is attained by providing said part in the region of the shoulder disposed on the wiper arm with a groove open at the top and facing away from the carrying element and in which the shoulder crosses the coupling part. 
     When the wiper arm together with the wiper blade must be moved away from the windshield, for example to replace the wiper blade, an uncontrolled separation of the wiper blade from the wiper arm can be prevented by making the distance, in the longitudinal direction of the wiper blade, from the bearing bore over the transverse groove to one end of the wiper blade greater than to the other end of the wiper blade. In this manner, because the center of gravity has been displaced, the half of the wiper blade lying next to the wiper arm is turned toward the shoulder so that the wiper blade comes to rest by itself between the leg of the shoulder and the wiper arm or the swiveling lever thereof where it is secured. Inadvertent separation of the wiper blade from the wiper arm is thus not possible, because for this to happen, the wiper blade would have to be turned toward the wiper arm so as to displace it from the securing region of the leg. 
     A particularly simple configuration of the matching regions of the wiper blade is obtained when said regions are formed on the two long sides of the coupling part that face one another. 
     To minimize lateral play between the wiper blade and the support regions of the wiper arm, the distance, measured in the direction of the joint axis, between the matching regions of the wiper blade is adapted to the distance between the support regions of the wiper arm, because in this manner the side walls of the groove absorb at least part of the forces acting on the wiper blade—forces that can arise, for example, as a result of uneven soiling of the windshield—and thus relieve the load from the joint pin or the bearing pin. 
     Facilitated guidance of the wiper blade and thus a particularly quiet wiping operation can be achieved when, measured in the longitudinal direction of the wiper blade, the width of the shoulder is adapted to the width of the groove. 
     For a wiper blade which at least in the region of the joint pin has a U-shaped cross-section, whose U-leg faces the windshield, the joint pin can be fastened in simple manner by making said pin pass through the U-leg in a recess in proximity to the wiper blade and fastening said pin on the other U-leg. 
     Advantages for the bearing position of the wiper apparatus can arise when a separate connecting piece is fastened at the free end of the wiper arm or swiveling lever, said connecting piece being provided with both the joint pin and the securing means for the wiper blade. 
     When the wiper arm or the swiveling lever thereof are in the form of an injection-molded part, the joint pin can be connected with the wiper blade or the swiveling lever in simple fashion by molding one of its ends to the wiper blade. 
     Other advantageous features and embodiments of the invention are indicated in the following description of the embodiment examples shown in the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, 
     FIG. 1 shows a side view of the wiper blade belonging to the wiper apparatus of the invention; 
     FIG. 2 shows a top view of the wiper apparatus with the wiper blade according to FIG. 1; 
     FIG. 3 is a representation in perspective of a magnified detail of the wiper apparatus of FIG. 2, indicated by III; 
     FIG. 4 shows a section through the wiper blade of FIG. 3 along line IV—IV, appropriately turned; 
     FIG. 5 shows a section through the wiper arm of FIG. 3 along line V—V, appropriately turned; 
     FIG. 6 shows a top view of the injection-molded free end of a possible embodiment of the wiper arm; 
     FIG. 7 shows a section through the wiper arm of FIG. 6 along line VII—VII, appropriately turned; 
     FIG. 8 shows a section through the wiper arm of FIG. 6 along line VIII—VIII, appropriately turned; 
     FIG. 9 is a partial representation, not to scale, of the wiper arm connected with the wiper blade wherein the wiper arm together with the wiper blade is pushed into a mounting position away from the windshield; 
     FIG. 10 shows the arrangement of FIG. 9 in operating position; 
     FIG. 11 shows a magnified representation of a section through the wiper apparatus of FIG. 10 along line XI—XI, and 
     FIG. 12 shows a magnified representation of a section through the wiper apparatus of FIG. 10 along line XII—XII. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A wiper apparatus  10  for motor vehicle windshields, shown in FIG. 2, comprises a driven wiper arm  12  located on the motor vehicle body, with a wiper blade  14  linked to its free end. The articulated linkage between wiper arm  12  and wiper blade  14  consists of an appropriately made connecting device  16 . Wiper arm  12  and thus also wiper blade  14  are stressed in the direction of arrow  18  [sic—“arrow  18 ” is not shown in the drawing—Translator] toward a motor vehicle windshield  20 , indicated in FIG. 1 by a dash-dot line, with which an elongated, elastic wiping strip  22  can be brought in contact. In the resulting operating position, the wiper blade is displaced over the windshield in the direction of the double arrow  24  (FIG. 2) to clean the surface  28  thereof. In FIG. 1, however, wiper blade  14  is shown in a position in which only its two ends touch windshield  20 . Wiping strip  22  of wiper blade  14  is disposed parallel to the longitudinal axis on the side of strip  25 , facing windshield  20 , of a one-part strip-like carrying element  26 . On the other side of strip  27  of carrying element  26 , facing away from windshield  20 , is fastened on the wiper blade side, in the center portion thereof, a device part  30  belonging to connecting device  16 . As can be seen from FIG. 1, the wiper blade in its represented position in which it does not yet touch windshield  20  in its entire length is more strongly curved than is the windshield. Because FIG. 1 shows the strongest curvature of windshield surface  28 , it is clearly evident that the curvature of wiper blade  14  touching windshield  20  with both its ends is greater than the maximum windshield curvature. Under the applied pressure (arrow  18 ), the wiper blade along its entire length touches with its wiping lip  32  the windshield surface  28  to be wiped. This produces in the elastic carrying element  26  a tension which provides for appropriate contact between the entire length of wiping strip  22 , or of wiping lip  32 , and windshield  20 . Because the windshield, which normally is curved in spherical fashion, is not a segment of a spherical surface, wiper blade  14 , unlike wiper arm  12 , must at all times during its wiping motion (double arrow  24 ) be able to adapt itself to the particular position of the windshield. For this reason, connecting device  15  [sic—“connecting device  16 ” seems to be meant—Translator] is designed also as an articulated connection between wiper blade  14  and wiper arm  12 . 
     In the following, two embodiment examples of the connection between the wiper blade and the wiper arm will be described in greater detail. As can be seen from FIG. 3, wiper blade  14  is provided with a one-part, strip-like carrying element  26 . In the center portion of the wiper blade shown here is located on the side of the wiper blade the device part, or coupling part,  30  with the aid of which wiper arm  12  can be connected with wiper blade  14  in an articulated manner. Device part  30  which in this embodiment example is made of plastic is rigidly connected with the wiper blade or the carrying element  26  thereof. It has a block-shaped section  34  in which is disposed a bearing bore  36  in the form of a blind hole. Bearing bore  36  is located in the block-shaped section  34  of the connecting part, near one of the longitudinal ends thereof. At the other longitudinal end is connected to section  34  of device part  30  a groove  38  oriented transverse to the longitudinal direction of wiper blade  14 , said groove at its top being open toward the side facing away from carrying element  26 . End section  40 , which toward the other end of device part  30  is in the proximity of cross groove  38 , is also shaped like a block, but is not as high as section  26  with bearing bore  36 . From this it follows that the height of section  34  of device part  30  is the greatest relative to the upper side  27  of carrying element  26 . In FIG. 11, this height is indicated by reference number  42 . The height of device part  30  is smallest in the region of cross groove  38  or of the groove bottom. This height is indicated in FIG. 12 by reference number  44 . The height of section  40  corresponds to height  42  of section  34  in the embodiment example. It is also quite possible to retain height  44  from the groove region over section  40  of device part  30  so that instead of groove  38  a shoulder is formed. Moreover, device part  30  is provided in the region of its section  40  beyond cross groove  38  with inclined surfaces  46 . Inclined surfaces  46 , however, are sized so that side cheeks  48  are retained over the entire length of device part  30  on both of its longitudinal sides which face each other and which extend from section  34  beyond cross groove  38  to the end of section  40  of device part  30  (FIG.  3 ). 
     Moreover, FIG. 3 shows the free end on the connection side of wiper arm  12  which free end in this embodiment is in the form of a non-cutting sheet metal part. It has a swiveling lever  50  extending from a bearing location  52  (FIG. 2) on the motor vehicle body and has a U-shaped cross-section, at least over large regions. The U-legs  54  of swiveling lever  50  are oriented toward the windshield  20  to be wiped. Close to its free end which is located away from bearing location  52 , the swiveling lever is provided with a joint pin  56  which has a smooth surface and whose axis  55  extends essentially in the direction of the wiper arm motion (double arrow  24  in FIG.  2 ). The diameter of joint pin  56  is adapted to the diameter of the bearing bore  36  in device part  30  in a manner ensuring a virtually play-free, smooth fit which allows an unhindered swinging motion of wiper blade  14  about axis  55  of joint pin  56 . As can also be seen from FIG. 3, the U-base  58  of swiveling lever  50  extends with an L-shaped shoulder  60  outward beyond one U-leg  54 , the one L-leg  61  connected with U-base  58  being oriented transverse to the extension of swiveling lever  50 . The other L-leg  62  [sic—Translator] is oriented toward windshield  20 . Distance  64  from the free end of wiper blade  12  or swiveling lever  50  to joint axis  55  is smaller than the distance  66  from the free end of the wiper arm or swiveling lever  50  to the L-shaped shoulder  60 . 
     When, as in FIG. 3, wiper blade  14  is to be attached to the connection end of wiper arm  12  (FIG.  3 ), wiper arm  200  must first be brought into a position—deflected from windshield  20  in the direction opposite to that of arrow  65  [sic—Translator]—as shown in FIG.  9 . Moreover, as shown in FIG. 9, wiper blade  14  must then assume the position relative to the wiper arm in which the L-leg  62  of the L-shaped shoulder  60  belonging to wiper arm  12  assumes the position, seen in FIG. 9, relative to cross groove  38  of the device part  30  belonging to wiper blade  14 . It is necessary to ensure an appropriate adaptation of the distance from the joint axis to the two side walls of the groove on one side to the distance from the joint axis to the side edges of one L-leg  61  connected to swiveling lever  50  of wiper arm  12 . When the mounting position between wiper arm  200  and wiper blade  14 , represented in FIG. 9, is realized, wiper blade  14  can be pushed in the direction of joint axis  55  onto joint pin  56  of the wiper arm until side cheek  48  presenting the opening of bearing bore  36  touches the wiper arm or a rigid shoulder of the wiper arm. In this intermediate mounting position, wiper blade  14  can be turned relative to wiper arm  200  in the direction of arrow  86  (FIG. 9) as shown in FIG.  10 . The wiper arm can then also be swung back in the direction of arrow  85  (FIG. 9) and thus brought into its operating position in which wiper blade  14  closely conforms to the surface  28  of windshield  20  to be wiped (FIG.  10 ). The relative movement between the wiper arm and the wiper blade is possible because distance  68  (FIG. 12) between the inner side of leg  62  facing wiper arm  12  is adapted to a length  70  which on the wiper blade or, in the embodiment example, on device part  30  is measured in the direction of joint axis  55 . Here, the two Measuring sites must not necessarily face each other. In the embodiment example, one measuring region  72  is on the side cheek  48  of device part  30  which when the wiper blade is mounted on the wiper arm is in direct proximity to the inner side of L-leg  62 . The other measuring region  74 , in the embodiment example shown in FIG. 11, is formed by the collar  76  of a bearing bushing  78  the bore of which takes over the bearing function for joint pin  56  and which, in turn, rests firmly in device part  30 . Here, the front face  80  of collar  76  serves as the reference point for measuring region  74 . 
     In the configuration of device part  30  according to FIG. 3, the measuring sites for length  70  are formed by the two long sides or side cheeks  48  of device part  30  itself. It is important that in the operating position of the wiper apparatus shown in FIGS. 11 and 12 the one side cheek  48  of the wiper blade, or the measuring regions  72  and  74  of the wiper blade, faces directly the inner side  63  of L-leg  62  or measuring region  75  for the distance  68  on wiper arm  12 . L-leg  62  or its inner wall  63  facing the wiper arm, together with the measuring site  75  that faces said inner wall, forms on the wiper arm support regions which are located at a distance  68  from one another in the wiping direction and are oriented toward one another. Between these support regions  63  and  75  of the wiper arm lie matching regions  72 ,  74  of the wiper blade, said regions facing away from one another and being formed by the front face  80  of collar  76  or on the side cheeks  48  of device part  30 . 
     It can be seen from FIGS. 2 and 3 that, measured in the longitudinal direction of wiper blade  14 , the distance  82  of the bearing bore or of the joint axis  55  over the cross groove  38  to one end of the wiper blade is greater than the distance  84  from joint axis  55  to the other end of the wiper blade. Because the center of gravity is thus fixed and displaced toward one end of the wiper blade, when the wiping apparatus  10  swings away from windshield  20  in the direction opposite to arrow  85  in FIG. 9, a moment is created which turns the wiper blade about the joint axis  55  in the direction of arrow  86  so that said blade with the side cheeks  48  of device part  30  always remains between the securing means  63 ,  75  of wiper arm  1   2  and is thus protected against inadvertent separation of the wiper arm. 
     The necessarily specified operating location of wiper blade  14  between the securing means of the wiper arm avoids erroneous mounting with certainty, because otherwise the visually clearly recognizable operating position between wiper arm and wiper blade cannot be attained. 
     The use of bearing bushing  78  in place of blind hole  36  shown in FIG. 3 has advantages in terms of the adaptation of the sliding partners. 
     Note regarding the configuration according to FIGS. 11 and 12 that here the wiper blade is not provided with a one-piece carrying element, but that said element consists of two part rails  102  which rest in longitudinal grooves  104  of wiping strip  106  [sic—Translator]. Part rails  102  are secured in their longitudinal grooves  104  by the fact that device part  30  overlaps and grips from below in claw-like fashion the longitudinal edges of the part rails, which rails face away from each other. Moreover, FIGS. 4,  5 ,  11  and  12  show that in a wiper arm  12  made of sheet metal and having a U-shaped cross-section whose U-leg  54  is oriented toward windshield  20 , joint pin  56  passes through the U-leg  54  in a recess  108  in proximity to wiper blade  14  and is fastened, preferably riveted or welded, to the other U-leg  54 . 
     In another embodiment of the wiper arm  12  shown in FIGS. 6 to  10 , said arm is provided at its free end with a separate connecting piece  202  made by casting or injection-molding, which has both joint pin  204  and securing part  208  for the wiper blade. In this case, the joint pin is molded to the massive end piece  206  of the wiper arm. In this embodiment, it is clear that the L-shaped shoulder  208  is molded directly onto connecting piece  202 . The arrangement and configuration of joint pin  204  and of the L-shaped shoulder  208  per se and relative to one another are entirely equivalent to the embodiment of the invention explained by reference to FIGS. 3 and 12. 
     To improve the guidance of the wiper blade on the wiper arm and to reduce the load on bearing means  36  or  56  of the wiper arm and the wiper blade, it may be advantageous to fittingly adapt to each other the width of one L-leg  61 , measured in the longitudinal direction of the wiper arm, and the width of cross groove  38 . 
     The two embodiment examples have in common the feature that the securing means for wiper blade  14  are disposed on wiper arm  12  and that on the side of the wiper blade facing away from the wiper arm said means cooperate with a stop on the wiper blade side, said stop being formed by the inner wall of the other L-leg  62 . It is clear that the securing of the wiper blade on the joint pin toward the other side is taken over by the wiper arm itself, because the joint pin is fastened to this wiper arm.