Abstract:
A retractable Targa roof system having a windshield header, a pair of side pillars, a rollbar, a backlight, a single pivoting roof panel and at least one pivot-carrying buttress. The rigid roof panel has at least one fixedly attached swing arm independent of the side pillars and pivotally articulated to said buttress. The buttress pivot is positioned between the bases of the side pillars in transverse direction and substantially above the belt line of the vehicle. Various arrangements of the system allow for a rearward rotary motion to bring the roof panel into either externally retracted position above a forward-hinged deck lid, or internally retracted position under a rear-hinged deck lid.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a convertible motor vehicle with a moveable roof, particularly a rigid roof panel, which can be pivoted rearward around a horizontal transverse axis to its opened position on top of or under the rear deck lid. 
   U.S. Pat. No. 4,950,022 (Pattee) describes a motor vehicle where the pivoting hardtop comprises right and left side leg members, which form upper halves of B-pillars accordingly. Lower halves of the pillars support the pivots, and the backlight is made removable. A disadvantage in this case is that unfeasible sealing conditions exist between the bases and moveable upper halves of the pillars. The pivoting pillars also result in a poor side glass seal, and the rear glass has to be displaced during retraction of the top. 
   Furthermore, from U.S. Pat. No. 6,527,332 (Fioravanti), a moveable top is disclosed as a one-piece shell pivoted to the inner surfaces of B-pillars. As in the previous sample, here the pillars are not connected by a rollbar of any kind, which results in a weak structure and chronic misalignment of the moveable top to the body of the vehicle. This top has notoriously poor sealing conditions at the side pillars, as well as at the bottom of the pivoting backlight. 
   In both cases the rotating rear window takes considerable space from the cockpit, reducing legroom. Because the top is pivoted directly to the side pillars, the inner surfaces of said pillars are limited to being vertical in the rear view. Noticeably, the appearance of vertical B-pillars is aesthetically uncertain, especially for vehicles of this type. Also the roof in its opened position overlays the entire deck immediately aft of the rear glass, which would block ventilation openings in cars with midengine layout. Moreover, these systems jeopardize overall safety of a car as they lack any protective rollbar. 
   Consequently, there remains a need for a convertible roof system with a simple, robust design, while improving safety and packaging of a car. 
   SUMMARY OF THE INVENTION 
   It is an object of the invention to provide a convertible roof construction with a rollbar system, common type seals, and a cockpit space which is not reduced neither during the roof operation nor in its opened position. 
   This object has been achieved by providing the roof panel with a swing arm(s) pivoted to supplementary buttress(es), instead of side pillars. The side pillars, particularly B-pillars of two-seat cars, carry inner trim panels as well as multiple seals to the roof, backlight, side glass, and door panels. It is advantageous with respect to efficiency that in this invention the buttress/swing arm arrangement is free of those functions and dedicated to roof pivoting. As a result, the roof panel has independent means of pivoting and does not have to be sealed to the inner surfaces of the side pillars. Thus, the side pillars can support a conventional rollbar. The separate pivoting mechanism is more reliable while preserving the overall structural integrity of the system. 
   Preferably, two swing arms are equidistantly spaced further inboard from the sides of the roof panel. This layout provides superior support and structural rigidity necessary for the moving roof panel. It also results in a less obstructed rear view. The buttress/swing arm design is possible in a variety of styles with different finishes, trim and garnish pieces. 
   The roof panel can be retracted either externally or internally, depending on dimensions and packaging of a specific vehicle. In case of a forward tilting deck lid the roof panel rotates approximately a half-turn to an upside-down position on top of the deck lid. A moveable rear deck spoiler then overlaps and secures the roof in opened position. No seals are needed in addition to standard header and rollbar seals. Also, the buttress and swing arm may function as air or water directing elements. 
   Alternatively, a rearward tilting deck lid makes possible for the roof panel to be retracted inside the vehicle body. Corresponding notches are provided at the front edge of the deck lid and adjacent body panels to accommodate the swing arms. 
   The system can be configured such that when the roof is in its opened position there is a sufficient space between the roof panel and the backlight for ventilation openings in the rear deck of midengine cars. An auxiliary swing arm swivel or lift mechanism may be provided for specific motion control of the roof panel during beginning and ending phases of operation. The roof panel locks engage with the front header or the rear spoiler, securing the roof in its closed or opened position respectively. The invention will become more readily apparent from the following description thereof on the basis of the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an isometric rear view of a vehicle with a central buttress and the roof closed. 
       FIG. 2  is a partial isometric rear view of a vehicle greenhouse with a central buttress and the roof panel in a transitional (half-open) position 
       FIG. 3  is a schematic side view of the flying buttress with the roof panel in closed position. 
       FIG. 4  is an isometric rear view of the system with two independent buttresses, the swing arm shaped as an air scoop, and the roof panel in a transitional position. 
       FIG. 5  is a schematic side view of the flying buttress with auxiliary swivel mechanism. 
       FIG. 6  is an isometric rear view of the system configured as a subassembly with a crossmember. 
       FIG. 7  is an isometric rear view of the system with a double-loop rollbar system and the roof panel in opened position. 
       FIG. 8  is a schematic side view of a moveable spoiler and the roof panel in opened position. 
       FIG. 9  is an isometric rear view of the system with a rear-hinged deck lid. 
       FIG. 10  is an isometric rear view of the system with a swing arm aperture between the rollbar and the rear-hinged hatchback lid. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The base system, as shown in  FIGS. 1 and 2 , has a windshield header  1 , a pair of side pillars  2  supporting a rollbar  3 , a non-pivoting backlight  4 , and a single pivoting roof panel  6 . The roof panel  6  is articulated to a central mounted buttress  7  via swing arms  9  and buttress pivots  8 . 
   This system is adaptable for cars with midengine layout. Central buttress  7  is incorporated into a structural backlight  4 , which supports the pivots  8 . The buttress  7  also functions as a transparent air duct with an inlet in the scoop  12  above the rollbar  3 . Elongated segments  10  of the swing arms  9  are integral reinforcement elements of the composite roof structure. They border left and right sides of the buttress  7  and form air-directing ribs on the roof surface. Slanted pylons  11  rotate the roof panel  6  approximately 180° rearward to an up-side-down position on top of the deck lid  5  and further back from the backlight  4 . Advantageously, with this arm geometry, the roof panel  6  in opened position does not obstruct the deck vents  13 . 
     FIG. 3  shows the system with a freestanding buttress  7  positioned behind the backlight  4 . A freestanding buttress is defined as an individual formation without structural connection to the rollbar  3  or side pillars  2 . A crossmember  15  at the back of the passenger compartment provides the most suitable support for a buttress positioned between side pillars. The crossmember  15  may be shaped as a beam, package shelf, or bulkhead with integrated gutter  16 . Additional reinforcing brackets, supports, extensions, or spacers may be used in connection with the buttress. 
   Preferably, two transversely spaced buttresses  7  with buttress pivots  8  are mounted on the crossmember  15  symmetrically to the vehicle&#39;s longitudinal centerline. This arrangement positions the swing arm pylons  11  predominantly in the dead zones of the rear field of view, minimizing the system&#39;s impact on the rearview visibility. 
   The swing arm  9  may have various types of construction.  FIG. 4  shows an aftermarket application where a one-piece swing arm  9  is made of lightweight composite and affixed to a transparent roof panel  6  shown here in a transitional position. The arm pylons  11  are integrated into an air scoop  12 , which directs air to a low-pressure area behind the backlight  4 . The deck lid hinge brackets  14  are shaped as extensions of the independent buttresses  7  forming two follower bodies typical of sports cars. 
   As illustrated in  FIG. 5 , a freestanding flying buttress  7  supports a lightweight alloy swing arm  9  with an auxiliary lift mechanism  20  sampled here as a double-hinge swivel lever. During the opening operation the lift mechanism  20  first carries out a swivel movement (A) resulting in the upward displacement (B) for the roof panel to clear the rollbar and the header (not shown). Then, a single rotation around the buttress pivot  8  moves the system into retracted position. Conversely, at the end of the closing cycle, the lift mechanism  20  lowers the roof until it is properly engaged with the rollbar and the header. The lift-out motion of the arm  9  can be controlled, for example, by a balance link or an actuator  21  and performed by a linear slide or other known means. In addition, the auxiliary lift mechanism  20  may be employed for guiding the roof panel into the trunk or under the rear spoiler. 
   In  FIG. 6  the system is configured as an aftermarket replacement for a soft top on convertible vehicles. The swing arms  9  are made of a lightweight alloy and bonded to a composite roof panel  6 . Two buttresses  7  are mounted on a lower body crossmember  15  with a gutter  16 , and support the rollbar  3 . They are spaced apart from the bases of the side pillars  2 . The buttress pivots  8  are positioned in front of the backlight  4  (not shown) allowing for the deck lid hinge brackets  14  to be articulated to the buttresses  7  at the same pivot points  8  as the swing arms  9 . 
   With reference to  FIG. 7  the system includes dual rollbars  3  supported by side pillars  2  and inner buttresses  7  with buttress pivots  8 . The swing arms  9  are shaped as a pair of structural ribs or gussets extending upward from the roof panel  6  shown in the externally retracted position, whereas the rear spoiler  17  overlaps the front edge of the roof panel  6 . The backlight  4  includes a moveable wind deflector (not shown) placed between the buttresses  7 . 
   Another feature of this invention is a spoiler  17  ( FIG. 8 ) positioned at the back of the rear deck. The spoiler in this case is made pivotable rearward around the pivot  18 , allowing the roof panel  6  to move into its fully retracted position C. The spoiler  17  then pivots forward overlapping the front edge of the roof panel and effectively locking it in place. The spoiler  17  is configured in cooperation with the leading edge of the roof panel to provide a refined appearance and streamlined aerodynamics to the system in an externally retracted position. The spoiler  17  can be made moveable by a four-bar mechanism, a linear slide, or other means, including an automatic actuator. It also can be positioned directly on the vehicle body or on the openable rear deck lid  5 . 
   In the embodiment of  FIG. 9  the longitudinal segments  10  of the swing arms are shaped as integrated oblong bulges on the surface of the composite roof panel  6 , while the swing arm pylons  11  are made of metal stampings. The rearward tilting deck lid  5  allows the roof panel  6  to be internally retracted into position D. The rear deck has an aperture  22  between the backlight  4  and deck lid  5  for the pylons  11  to pass through when the roof is in position D under the deck lid  5 . The aperture  22  may be sealed when not in use. The roof panel  6  may partially or completely overlay the rollbar  3  when closed. 
     FIG. 10  shows the system with internally positioned buttresses  7  mounted on the crossmember  15 , whereas a rearward tilting deck lid  5  includes a backlight  4 . In this configuration the system contains apertures  22  (one is shown) in the backlight frame for the swing arms to pass through when the roof  6  is up (closed position). Conventional gaskets may be used to seal the swing arm  9  in the aperture  22 . 
   As shown in  FIGS. 1 to 10  a specific location of the buttress pivots  8  depends on height and width of the rollbar  3 , and determines the length and the angle of the swing arms  9 . These parameters are critical for kinematics of the system, which may be actuated either manually with assistance of conventional balance links, or automatically through the use of an auxiliary motor drive with a manual override for the deck lid operation. 
   The foregoing disclosure, detailed description and specific examples, while indicating the preferred embodiment of the invention, have been set forth merely to illustrate the invention and are not intended to limit its coverage. For example, the swing arm may form a convex or concave profile on the roof surface, such as a rib, ridge or corrugation. It may be shaped as a wind deflector, air intake, fin, or wing. The buttress and the swing arm may function as a water-directing gutter. Also, the buttress  7  may be constructed as a roof drive mechanism, and may have adjustment means for alignment of the swing arm  9  to the buttress pivot  8 . An additional crossmember may be positioned above an existing lower crossmember to support the buttresses  7 . The deck lid  5  can be articulated to the vehicle body using a four-bar operating mechanism. 
   Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.