Abstract:
A vehicle convertible roof is provided which includes mechanisms to actively control at least a majority of the roof bows. The active controlling of the roof bows allows the convertible roof to have a stacked length that is reduced and results in a smaller packaging requirement. A unique and novel way to control the movement of the front roof rail relative to the center roof rail is disclosed. The simple linkage arrangement reduces the complexity of the vehicle convertible roof and provides for compact packaging of the convertible roof when in the stowed position thus reducing the packaging requirement.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     This invention relates generally to a convertible roof for automotive vehicles and, more particularly, to a “Z” fold convertible roof. 
     Soft-top convertible roofs in automotive vehicles typically employ three, four or five roof bows, each having an inverted U-shape spanning transversely across the vehicle for supporting a vinyl, canvas or polyester fabric, pliable roof cover. A number one roof bow is mounted to a pair of front roof rails and is typically latched to a stationary front header panel of the automotive vehicle body disposed above the front windshield. A number two roof bow is typically mounted to a pair of center roof rails which are pivotally connected to the front roof rails. Furthermore, the number three, four and any additional optional roof bows are commonly mounted to a pair of rear roof rails which are pivotally coupled to the center roof rails. The roof cover can also have a hard or rigid portion along with a pliable portion. For example, reference should be made to U.S. Pat. No. 5,429,409 entitled “Convertible Top” which is incorporated by reference herein. Most traditional convertible roofs are stowed in a boot well or stowage compartment that is located aft of a passenger compartment in the vehicle. A boot or tonneau cover is then used to cover the boot well and conceal the convertible roof from view and/or protect the stowed roof from the environment. 
     Traditional soft-top convertible roofs can present stowed packaging difficulty when it is desired to use a “Z” folding roof. Traditional “Z” folding roofs have second and subsequent roof bows that are passively controlled and rely upon the movement of the flexible cover to position the roof bows when the convertible roof is transitioned from raised and stowed positions. They also typically have three pairs of coupled roof rails. Passively controlling the second and subsequent roof bows, however, may not position the second and subsequent roof bows in a proper orientation or may require excessive stowage space. Additionally, controlling the movement of the front roof rail relative to the center roof rail often requires complex linkages to properly position the front roof rail above the center roof rail when in the stowed position. Therefore, it would be desirable to actively drive the second and subsequent roof bows to control the position of the roof bows when transitioning from raised and stowed positions. It would also be desirable to provide a “Z” folding roof that utilizes a simple and unique linkage arrangement to control movement of the front roof rail relative to the center roof rail when transitioning from raised and stowed positions. 
     In accordance with the present invention, a vehicle convertible roof is provided which includes mechanisms to actively control at least a majority of the roof bows. The active controlling of the roof bows allows the convertible roof to have a stacked length that is reduced and results in a smaller stowed packaging space. In another aspect of the present invention, a unique and novel way to control the movement of the front roof rail relative to the center roof rail is disclosed. The simple linkage arrangement reduces the complexity of the vehicle convertible roof and provides for compact packaging of the convertible roof when in the stowed position thus reducing the packaging requirement. 
     Along with actively controlling at least a majority of the roof bows and controlling movement of the front roof rail relative to the center roof rail, additional objects, advantages and features of the present invention will become apparent from the following description and dependent claims, taken in conjunction with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is a side elevation view showing the preferred embodiment of a vehicle convertible roof of the present invention in a raised position; 
     FIGS. 2A-B are side elevation views showing the preferred embodiment of the convertible roof of the present invention in different partially retracted positions; and 
     FIG. 3 is a side elevation view showing the preferred embodiment of the vehicle convertible roof of the present invention in a fully retracted or stowed position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     FIGS. 1-3 show the preferred embodiment of a vehicle convertible roof employed in a convertible roof system  20  on an automotive vehicle  22  of the present invention. Convertible roof system  20  includes a linkage assembly or top stack mechanism  24  covered by a pliable fabric roof covering  26 . More specifically, top stack mechanism  24  includes a number one or forwardmost roof bow  28 , a number two roof bow  30 , a number three roof bow  32 , and a number four or rearmost roof bow  34 . Two, three and four bows  30 ,  32  and  34  are preferably hollow and tubular metallic members although alternate extruded, molded or stamped shapes can be employed. Convertible roof system  20  is moveable from a raised or extended position covering vehicle passenger compartment  36 , as shown in FIG. 1, through intermediate positions, such as those shown in FIGS. 2A-B, to a fully retracted or stowed position within a boot or stowage area  38 , as shown in FIG.  3 . 
     Vehicle  22  has a tonneau panel mechanism that includes a tonneau panel  40  which is operable between open and closed positions to allow retraction and extension of top stack mechanism  24  to/from stowage area  38 . When convertible roof system  20  is in the stowed or retracted position, tonneau panel  40  conceals at least a portion of top stack mechanism  24 . The actuating mechanism for moving tonneau panel  40  between the open and closed positions can be that disclosed in U.S. Pat. No. 5,743,587 entitled “Apparatus for Use in an Automotive Vehicle having a Convertible Roof System” which issued to Alexander et al., the disclosure of which is incorporated herein by reference. 
     Convertible roof system  20  and top stack mechanism  24  are symmetrical about a longitudinal, fore-and-aft center line (not shown) of vehicle  22 . Top stack mechanism  24  includes right and left roof linkages on the respective right and left sides of vehicle  22 . For brevity, only the right side of top stack mechanism  24  is shown and discussed, however, it should be understood that left side linkages are also provided as part of top stack mechanism  24  and are substantially mirror images of the right side. When using the terms “fore” and “aft” and “front” and “back” in describing components of top stack mechanism  24 , such reference refers to the orientation of the component when top stack mechanism  24  is in the fully raised or extended position. Also, when using the terms clockwise and counterclockwise in describing rotation of components of top stack mechanism  24 , such reference refers to rotation relative to the view depicted in the Figures. 
     Referring to FIGS. 2A-B, convertible roof system  20  is shown with top stack mechanism  24  in partially retracted positions. Top stack mechanism  24 , in addition to including the four roof bows  28 ,  30 ,  32  and  34 , also includes a front roof rail  42 , a center or intermediate roof rail  44  and a rear roof rail  46 . Number one roof bow  28  and number two roof bow  30  are fixedly attached to front roof rail  42  and move with movement of front roof rail  42 . Front roof rail  42  is coupled to center roof rail  44  by first and second links  48  and  50 . One end of first link  48  is pivotally connected to an intermediate portion of front roof rail  42  at pivot  52  while the other end of first link  48  is pivotally connected to a front portion of center roof rail  44  at pivot  54 . One end of second link  50  is pivotally connected to a rear portion of front roof rail  42  at pivot  56  while the other end of second link  50  is pivotally connected to an intermediate portion of center roof rail  44  at pivot  58 . Front roof rail  42 , first link  48 , center roof rail  44 , and second link  50  form a parallelogram four-bar linkage assembly defined by pivots  52 ,  54 ,  58  and  56  that allows front roof rail  42  to move relative to center roof rail  44 . One end of a first control link  60  is pivotally attached to an intermediate portion of second link  50  at pivot  62 . First control link  60  is operable to control movement of front roof rail  42  relative to center roof rail  44  when top stack mechanism  24  moves between the raised and stowed positions, as described below. 
     Rear roof rail  46  is fixedly attached to a drive link  64  which is pivotally attached to vehicle  22  at pivot  66 . Rear roof rail  46  can be a separate. component that is fixedly attached to drive link  64  or can be integral to drive link  64  such that drive link  64  and rear roof rail  46  are a single component. A rear portion of center roof rail  44  is pivotally attached to rear roof rail  46  at pivot  68 . The rear portion of center roof rail  44  is also pivotally attached to a balance link  70  at pivot  72  which is forward of pivot  68 . Balance link  70  is pivotally attached to a vehicle  22  at pivot  74 . Drive link  64  (and rear roof rail  46 ), center roof rail  44 , balance link  70  and vehicle  22  form a four-bar linkage assembly defined by pivots  66 ,  68 ,  72  and  74  which controls movement of center roof rail  44  relative to rear roof rail  46  and vehicle  22 . A powered actuator  76 , in this case in the form of a hydraulic cylinder, is attached to vehicle  22  and drive link  64 . Actuator  76  is operable to selectively cause drive link  64  to rotate about pivot  66  and cause top stack mechanism  24  to move between its raised and stowed positions, as described below. An end of first control link  60  is pivotally connected to an end of drive link  64  at pivot  78 . Movement of first control link  60  is controlled by movement of drive link  64 . Because, as stated above, first control link  60  controls movement of front roof rail  42  relative to center roof rail  44 , drive link  64  also controls movement of front roof rail  42  relative to center roof rail  44  via first control link  60 , as described in more detail below. Actuator  76  is preferably a hydraulic cylinder but can also take other forms. For example, actuator  76  can alternately be an electric motor or another suitable power transfer mechanism. 
     Number three roof bow  32  is pivotally connected to drive link  64  at pivot  80  which is adjacent pivot  78 . Number four roof bow  34  is also pivotally connected to drive link  64  at pivot  82 . One end of a second control link  84  is pivotally connected to number three roof bow  32  at pivot  86 , which is adjacent pivot  80 , while the other end of second control link  84  is pivotally connected to number four roof bow  34  at pivot  88  adjacent pivot  82 . Second control link  84  controls rotation of number three roof bow  32  about pivot  80  when top stack mechanism  24  is moving between its raised and stowed positions, as described below. Thus, number four roof bow  34  via second control link  84  controls rotation of number three roof bow  32  about pivot  80 . 
     One end of a third control link  90  is pivotally connected to number four roof bow  34  at pivot  92  while an opposite end of third control link  90  is pivotally connected to an end portion of balance link  70  at pivot  94 . Third control link  90  controls movement and positioning of fourth roof bow  34  when top stack mechanism  24  moves between its raised and stowed positions, as described below. 
     In operation, convertible roof system.  20  and top stack mechanism  24  is moved from the raised position depicted in FIG.  1  through intermediate positions, such as the ones depicted in FIGS. 2A-B, to the stowed position depicted in FIG. 3 by first unlatching number one roof bow  28  from header  96  above windshield  98  on vehicle  22 . An operator engages a switch (not shown) located in passenger compartment  36 . The switch is connected electrically to actuator  76  to control the operation of top stack mechanism  24 . When convertible roof system  20  is used in conjunction with a manually operated tonneau cover, a simple switch may be implemented without the need for sophisticated electronic controls, proximity switches and/or sensors. However, the convertible roof of the present invention may be operated in conjunction with a power operated tonneau cover as previously discussed. In this case, the switch is connected electrically to an electronic control unit (not show), such as a microprocessor, that controls the operation of top stack mechanism  24 . The electronic control unit sends a signal to operate actuator  76  and to operate an actuator coupled to tonneau panel  40 . Devices such a limit switches, sensors and potentiometers are coupled to the body of vehicle  22 , tonneau panel  40  and convertible roof system  20  to inform the electronic control unit of the position of tonneau panel  40  and convertible roof system  20  to insure that convertible roof system  20  does not interfere with tonneau panel  40  during movement between the stowed and raised positions. 
     Actuator  76  is pivotally coupled to and powered to drive drive link  64  to move convertible roof system  20  between the raised and stowed position. Actuator  76  causes drive link  64  to rotate clockwise about pivot  66 . As drive link  64  rotates, first control link  60  causes front roof rail  42  to move relative to roof rail  44  in an upward and rearward direction while first and second links  48  and  50  rotate clockwise about their respective pivots  54  and  58  on center roof rail  44 . The rotation of drive link  64  also causes balance link  70  to rotate about pivot  74  in a clockwise direction. Rotation of drive link  64  and balance link  70  cause center roof rail  44  to rotate relative to rear roof rail  46  counterclockwise about pivot  68 . 
     Rotation of drive link  64  and balance link  70  also cause number four roof bow  34  to be pulled forwardly by third control link  90  which causes number four roof bow  34  to rotate counterclockwise about pivot  82 . The counterclockwise rotation of number four roof bow  34  about pivot  82  causes second control link  84  to push number three roof bow  32  forwardly and rotate counterclockwise about pivot  80 . Actuator  76  continues to cause drive link  64  to rotate clockwise about pivot  66  until top stack mechanism  24  and convertible roof system  20  is in the stowed position and resides within stowage compartment  38 , as shown in FIG.  3 . 
     When convertible roof system  20  and top stack mechanism  24  are in the stowed position, number four roof bow  34  and number three roof bow  32  have been rotated forwardly such that number four roof bow  34 , number three roof bow  32 , and number two roof bow  30  are all nested together and reduce the stack length of convertible roof system  20 . Additionally, front roof rail  42  is positioned above center roof rail  44  with an exterior portion of cover  28  facing upwardly. 
     Once in the stowed position, tonneau panel  40  can be lowered to its closed position to conceal at least a portion of top stack mechanism  24  and convertible roof system  20 . Thus, convertible roof system  20  provides a convertible roof that has a reduced stack length so that the required packaging space is reduced. The convertible roof system  20  also incorporates a unique way of controlling movement of the front roof rail  42  relative to the center roof rail  44  and causes front roof rail  44  to reside above center roof rail  44  when in the stowed position. 
     While it is apparent that the embodiment of the invention disclosed is well calculated to provide the advantages and features above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subsequent claims. For example, the convertible roof may include extra bows in the top stack mechanism. The convertible roof can also include generally rigid hardtop and soft-top combinations. Other materials and dimensions can be substituted for those disclosed. It is intended by the following claims to cover these and any other departures from the disclosed embodiments which fall within the true spirit of this invention.