Abstract:
The invention provides for a wiper arm for a windshield wiper system comprising a fixing element ( 12 ) for connection to a drive shaft, whereby a tiltably-fixed cover unit ( 24 ) is provided for at least partially releasing the fixing element ( 12 ). It is proposed that the cover unit ( 24 ) can be engaged with the fixing element ( 12 ) in the tilted position. A cover unit for a wiper arm is also proposed.

Description:
BACKGROUND OF THE INVENTION 
   The invention starts with a wiper arm, as well as a cover unit for a wiper arm. 
   Wiper systems with one or more windshield wipers for motor vehicles are fastened directly or indirectly with their wiper bearings via a mounting plate to the body of the motor vehicle. A motor shaft of a wiper motor directly or indirectly drives, for example via a rod, cranks, which are permanently connected with one end of a drive shaft for each windshield wiper. The drive shaft or the bearing axis is positioned in a wiper bearing. Provided in the bearing housing is at least one radial bearing and one axial bearing on the front sides between the bearing housing and a part that is permanently connected to the drive shaft. The drive shaft projects from the body and moves a wiper arm, which is fastened to its free end and has a wiper blade, over a windshield. As a rule, the wiper arm has a fixing element that is connected in a rotationally secured manner to the drive shaft, and this fixing element is connected in an articulated manner with an articulation part, on which a wiper rod is rigidly attached. This type of wiper system is known from DE 199 38 969 A1 for example. In the case of known wiper systems, the fixing element is covered at least partially with a capsule-shaped cover unit, which can be tilted in order to release the drive shaft for screwing the wiper arm on the drive shaft. 
   SUMMARY OF THE INVENTION 
   It is proposed in the case of a wiper arm in accordance with the invention that a cover unit in the tilted position can be engaged with a fixing element of the wiper arm. As a result, the cover unit can be put in a defined position, in which a worker can fasten the wiper arm to a drive shaft through the cover unit without being impeded, preferably by screwing on a front side of the drive shaft. The wiper arm can be mounted ergonomically and securely. Normally, the cover unit is already fastened to the wiper arm, if it is supposed to be mounted to a motor vehicle. The engagement is essentially provided for one-time use during mounting of the wiper arm; as a result, low requirements for stability of the engagement are adequate. The cover unit can therefore be manufactured cost effectively. The engagement between the cover unit and the fixing element can preferably be achieved by a positive engagement or even by locking into place in an undercut. 
   A particularly simple engagement is possible if the cover unit has an inwardly projecting rib on an inner side of at least one lateral wing. It is beneficial if an inwardly projecting rib is provided on the inner sides of both lateral wings. The lateral wings grip over the fixing element of the wiper arm at least partially. 
   If the rib is arranged in such a way that the rib can run at least along a contour of the fixing element when tilting the cover unit, the cover unit can be tilted freely until the rib engages. The cover unit is expediently tilted by approx. 90°. After going beyond a fixing point of the contour, a positive engagement can be produced between the rib and the contour or fixing element. The rib can then be adjacent in a positively engaged manner with the contour. The fixing point can be a formation of the contour, which prevents the rib from gliding over it freely. The rib cannot go beyond the fixing point on its own and therefore cannot tilt back if it has passed this point in the direction of an end position. The rib remains securely in place in the tilted position. A free passage for the assembly of the wiper arm on the drive shaft is guaranteed. Alternatively, an undercut can be provided on the contour into which the cover position hooks when tilting in its end position and which also prevents an undefined tilting back. The cover unit is secured during mounting of the wiper arm and undefined tilting back into its initial position is reliably prevented. Damage to the cover unit from tilting back is prevented. 
   If at least one nose for hooking on the fixing element is provided on the inner side of at least of one lateral surface of the cover unit, the cover unit can be tilted back simply after the worker mounts the wiper arm and can be securely and solidly locked by hooking the nose. The fixing element advantageously has a crosspiece corresponding to the nose, which the nose can grip under for fastening the cover unit. 
   Moreover, a cover unit for at least partially covering a wiper arm for a windshield wiper system is proposed, in which an inwardly pointing rib is provided on at least one of its lateral wings, which rib can produce an engagement with the fixing element of the wiper arm. The cover unit is preferably embodied to be capsule-shaped. The cover unit can be manufactured simply and cost effectively. The rib is provided essentially for one-time use during mounting of the wiper arm, a fact that makes the design and manufacture of the cover unit cost effective. 
   A reliable connection for long-term use on a wiper arm is possible if the at least one lateral wing has a nose on its inner side for hooking on the fixing element. 
   If both lateral wings each have a rib, the cover unit can be held stably in its tilted position for mounting the wiper arm. 
   The cover unit is preferably embodied of a glass fiber reinforced plastic. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described in greater detail in the following in an exemplary embodiment on the basis of the associated drawings. The drawings show: 
       FIG. 1  A view of a wiper arm with a cover unit and a wiper blade unit 
       FIG. 2  A detail of the arrangement from  FIG. 1  with a tilted cover unit in the assembly position 
       FIG. 3  A diagonal view of a cover unit 
       FIG. 4  A view of an inner surface of the cover unit from  FIG. 3   
       FIG. 5  A cross section through a cover unit 
   

   DETAILED DESCRIPTION 
   The same reference numbers are used for the same parts in the figures. 
     FIG. 1  shows a diagonal view of a wiper arm  10  with a wiper blade unit  16 . The wiper arm  10  has a fixing element  12 , which is connected in an articulated manner with an articulated arm  14 . The articulated arm  14  can include an articulated part and a rigidly attached wiper rod or be embodied as a single piece, preferably made of plastic. The wiper blade unit  16  is suspended on one end of the articulated arm  14 . The fixing element  12  is attached on the opposite end. The fixing element  12  has a bearing location on one end, which can be used to connect (e.g., to screw on via a bore hole) the fixing element  12  in a rotationally secured manner to the drive shaft via a fixing means on a drive shaft projecting from a vehicle body. Alternatively, other suitable fastening types can be selected. 
   The fixing element  12  is covered at least in the area of the connection to the drive shaft by the tiltably-fixed cover unit  24  for freeing the bore hole. The cover unit  24  is embodied to be capsule-shaped. In order to connect the wiper arm  10  to the drive shaft, the cover unit  24  is tilted approx. 90° forward in the direction of the articulated arm  14  and secured, as shown in  FIG. 2 . As a result, a bore hole  18  is freed, via which the wiper arm  10  can be fastened to a drive shaft. In a tilted position, the cover unit  24  can be engaged with the fixing element  12 . Attached on a lateral surface of the fixing element  12  is a crosspiece  20 , on which the cover unit  24 , which is tilted back into its initial position again after assembly, can be hooked in order to fasten this enduringly on the fixing element  12 . Such a crosspiece  20  is provided expediently on both lateral surfaces of the fixing element  12 . The cover unit  24  has an opening  42  on its upper side  40 , into which a finger of the articulated arm  14  projects. 
     FIG. 3  shows a diagonal view of a cover unit  24 . It is capsule-shaped, embodied approximately in a U-shaped manner with two lateral wings  26 ,  28  that are open to the front towards a front side  34  and are connected via a closed rear side  36 . The contours of the lateral wings  26 ,  28  on the front side  34  are adapted to the contour of the articulated arm  14  so that the cover unit  24  can be tilted. An opening  42  starting from the front side  34  is embedded in the cover unit&#39;s upper side  40 , which corresponds with a finger of the articulated arm  14  projecting into the opening  42  ( FIG. 2 ). The opening  42  is limited on each of the longitudinal sides of the cover unit  24  by a leg  46 ,  48 . If the cover unit  24  is tilted to mount the wiper arm  10 , the opening  42  offers space for the finger of the articulated arm  14 . 
   Furthermore, an inner surface of the lateral wing  26  of the cover unit  24  is recognizable. Adjacent to the leg  46  and away from the upper side  40 , an inwardly pointing rib  30  extends approximately parallel to the leg  46  and this rib forms a locking means to engage the cover unit  24 . Beneath the rib  30 , the lateral wing  26  features a rotational support  52  on its inner side, which can be connected with a corresponding holder on the fixing element  12 . The cover unit  24  is tilted around a rotational axis around this rotational support  52 . The inner surface of the opposite lateral surface is structured symmetrically and has a corresponding rib and rotational support (not shown). A nose  50  is arranged in a lower area on the inner surface of the lateral wing  26 , which can hook on a crosspiece  20  of the fixing element  12  ( FIG. 2 ), in order to connect the cover unit  24  as stably and enduringly as possible to the fixing element  12  after the wiper arm  10  is mounted. 
     FIG. 4  illustrates how a rib  32  of the lateral wing  28  can run along a contour  22  of a fixing element  12  when tilting the cover unit  24  around a rotational axis  38  of a rotational support (not shown). The rib  32  is arranged adjacent to a leg  48  in the area of the upper side  40  of the cover unit  24  parallel to the leg  48 . After going beyond a fixing point of the contour  22 , a positive engagement can be produced between the rib  32  and the contour  22 . The fixing element  12  is indicated as a dashed line for the sake of clarity. The fixing point prevents free movement of the cover unit  24 . After assembly is complete, the cover unit  24  is tilted back in the direction of the arrow. In the process, the fixing point of the contour  22  must be overcome with some application of force. 
     FIG. 5  shows a cross section through the cover unit  24  through an area with ribs  30 ,  32  and rotational supports  52 ,  54 . A first and second lateral wing  26 ,  28  form a U-shaped contour in cross section, which features an opening  42  in the apex, which is limited by legs  46  and  48 . Ribs  30 ,  32  are arranged along the contour in the direction of the rotational supports  52 ,  54  on the respective inner sides of the lateral wings  26 ,  28  between the legs  46  and  48  and the rotational supports  52 ,  54 . The cover unit  24  is embodied preferably of plastic, especially preferably of a glass fiber reinforced plastic.