From the patent document DE 37 45 013 C2, a wiper device holder with two unfoldable wings for incorporating or taking up a wiper system cover is known, whereby the wiper wings are jointed to each other. The two small face or side ends of this wiper system cover have been releasably clamped onto the small face or ends of the respective wing using swiveling bows or clips. In the working position, the two wings are positioned on one level. In order to form a lock-in, or catch, connection in the working position, one of the lock-in connections has a projecting nose which engages, or becomes interlocked, with the locking, or stopping, projection of the other wing. For releasing the lock-in connection, a latch has been provided through which the locking projection can be pivoted or swiveled away from the locking, or stopping, edge. Also from DE 102 10 569 A1, a two-parted foldable wiper plate is known with essentially the same structure or configuration.
A drawback of these already known foldable wiper plates is that the lock-in connection serving as the work position can only be achieved through great effort and skillfulness as well as high pressure onto the stick carrying the wiper plate. It is particularly disadvantageous that for unfolding the plate wing, as a rule, the wiper has to be lifted up with the stick so that the two wiper plates might fall to the ground owing to their balancing weight or load. This, however, is made considerably more difficult due to the fact that this operation has to be done simultaneously with foot-operating the release latch, or lever. In doing so, the load direction of the latch for releasing the lock-in connection is precisely in the opposite direction to the traction force, or power pull, direction of the stick which is required for the lifting-up operation as well as for effecting the unfolding operation. The user has to be very skilled in order to press simultaneously the lever, located on a wiper plate downward and to lift or to pull simultaneously the wiper plate up with the stick. If the user exerts too much pressure with the foot, it will not be possible to lift or to pull the wiper plate up with the stick. If the user exerts too little pressure onto the release lever, then the wiper plate can be lifted or pulled up with the stick, however, then the lock-in connection will not be released, or disengaged. Even if the user is skillful enough to master the difficult release operation, this operation will be considered strenuous and power- and time-consuming.
From DE 40 11 713 A1, a foldable wiper plate is known, in which the wiper plates in the working position are not locked-in to one another, or have not become interlocked with one another, but in which these plates are locked-in on a central part that is jointed to the wiper plates. Also here, a release latch or lever has been provided which for releasing the lock-in connection has to be pressed downward, while simultaneously, the wiper plate has to be lifted or pulled in an upward direction with the stick that is affixed to the plate. This foldable wiper plate has the same drawbacks as the two wiper plates already mentioned above.