1. Field of the Invention
This invention relates to a lowerable motor vehicle roof of the type having front and rear rigid roof elements, of which the first roof element can be moved, by means of a driving connecting rod mechanism which is located on the sides of the roof, between a closed position and a stowed position which is lowered in a convertible top compartment the first roof element, on its path into the stowed position, arriving in a position which at least partially overlaps the second roof element and entrains the second roof element into the stowed position,
Several structures are already known in which the two roof elements run in the lengthwise direction of the motor vehicle for opening the roof, and in doing so, are placed on top of one another and are stored jointly in a rear convertible top compartment, which is used at the same time as a trunk. For these motor vehicle roofs, generally, it is required that the connecting rod mechanism be as simple as possible, i.e., that it make do with as few hinges and drives as possible, and that the connecting rod mechanism be able to internest the roof elements in a space-saving manner, and then move them into a lowered position which requires as little stowage space as possible and which is optimally matched to the configuration of the convertible top compartment.
2. Description of Related Art
German Patent DE 197 14 106 C2 discloses a lowerable motor vehicle roof in which the two sides of the rear roof element are engaged by a first, driving connecting rod mechanism for moving the first roof element, in which the two sides of the front roof element are each engaged by a second, passive connecting rod mechanism for its guidance, and moreover, the front roof element is coupled to the rear roof element via another lever arrangement which engages the two sides. This arrangement meets the aforementioned requirements to the extent that the roof elements can be internested in a space-saving manner, the rear roof element with its concave side being pushed over the convex side of the front roof element, and that, then, the package composed of the front and the rear roof element can be stowed in the desired position in the trunk, which used as the convertible top compartment.
However, this known arrangement is extremely complex in terms of construction and operation since the driving connecting rod mechanisms alone each have six levers which are interconnected via seven hinges and are connected to the rear tail element, the passive connecting rod mechanisms have three levers each which are connected to one another via five hinges and to the front roof element, and the further lever arrangement has two levers which are connected via four hinges to the front and rear roof element, of which two are made as sliding hinges. Moreover, there is one actuating interlock for each driving connecting rod mechanism and for each passive connecting rod mechanism, and one actuating interlock for each of the sliding hinges.
Another disadvantage of the known arrangement is that, in it, the two levers of the further lever arrangement, in the internested position of the two roof elements, penetrate the roof skin of the front roof element so that the front roof element must be provided with the corresponding passage slots, with the generally recognized disadvantages with respect to their aesthetic design and rain-tight execution. A further disadvantage is also that the sequence of motion, for example, when opening the motor vehicle roof, proceeds relatively inharmonically since first the rear roof element is pushed in forward motion over the front roof element and then the two roof elements are lowered in the rear compartment jointly with a rearward motion.
German Patent DE 197 14 127 C2 discloses a lowerable motor vehicle roof in which the two sides of the rear roof element are engaged by a driving connecting rod mechanism for its displacement, and in which the front roof element is movable relative to the rear roof element via a driving connecting rod mechanism which engages the two sides of it. With regard to the connecting rod mechanism, this arrangement is simpler in terms of construction and operation than the arrangements according to German Patent DE 197 14 106 C2; but on each side of the roof, it has two driving connecting rod mechanisms, and accordingly, on each side of the roof, requires two displacement drives; this in turn increases structural and control engineering complexity.
Another disadvantage of this known construction is that its sequence of motion is relatively inharmonic, for example, when opening the motor vehicle roof since, first, the rear roof element is swung up, then, the front roof element is moved under the rear roof element, and then, the two roof elements are jointly swung down.