Abstract:
A convertible top operating mechanism includes a bi-directional hydraulic pump which is selectively connected to top-operating hydraulic cylinders and tonneau-operating hydraulic cylinders by a two-way, 5-condition control valve to selectively raise and lower the top and tonneau. A mechanical linkage connects the top-operating cylinders with a movable rear bow and is co-operable with a spring during operation of the top-operating cylinders when fully extending and initially retracting to move the rear bow to enable tonneau operation and to seal the top on the tonneau.

Description:
TECHNICAL FIELD  
         [0001]    This invention relates to automobile convertible tops and, more particularly, to a hydraulic operator for a convertible top having a movable rear bow.  
         BACKGROUND OF THE INVENTION  
         [0002]    Many convertible tops designed for high-end sports or other two-seat vehicles employ a movable rear or 5-bow. With the top lowered, the tonneau is opened to enable raising the top. The rear bow is then raised to enable closing of the tonneau. The rear bow is then lowered and secured to the tonneau to close the passenger compartment. To lower the top, the rear bow is raised to enable opening of the tonneau. The top is then lowered, after which the tonneau is closed. This system eliminates the need for a separate boot cover and presents a more aesthetically pleasing vehicle in both the top raised and lowered positions.  
           [0003]    Power tops that utilize a movable rear bow normally provide a pair of cylinders to operate the top, and require manual operation to raise and lower the rear bow or provide an additional pair of cylinders to operate the rear bow. These top operating systems are unduly complex and require use of complex valving to accomplish the correct sequence of top and bow movements to raise and lower the top.  
           [0004]    Developments have led to a hydraulic control system in which a single pair of cylinders can be used to sequentially operate both the top and rear bow movements operating through a mechanical linkage. Such a system is disclosed in U.S. Pat. No. 5,620,226—Sautter, the entire disclosure of which is incorporated herein by reference.  
           [0005]    There is a need for a convertible top operating mechanism which uses a simplified hydraulic control system to sequentially operate the top and tonneau movements to raise and lower the top.  
         SUMMARY OF THE INVENTION  
         [0006]    It is therefore an object of this invention to provide a for a convertible top operating mechanism which uses a simplified hydraulic control system to sequentially operate the top and bow movements to raise and lower the top.  
           [0007]    In general, this invention comprises a hydraulic control system for operating cylinders that control movement of a hydraulic top and cylinders that control movement of a tonneau.  
           [0008]    In one aspect this invention features a convertible top operating mechanism which includes a bi-directional hydraulic pump which is selectively connected to top-operating hydraulic cylinders and tonneau-operating hydraulic cylinders by a two-way, 2-condition control valve to selectively raise and lower the top and tonneau.  
           [0009]    In one embodiment, a mechanical linkage connects the top-operating cylinders with the movable rear bow and is operable to sequentially move the rear bow in a manner that accommodates tonneau operation in coordination with top operation.  
           [0010]    In a first valve position, both ends of the top cylinders are connected to both sides of the pump, while one end of the tonneau cylinders are connected to one side of the pump, and the other tonneau cylinder ends are blocked. When the pump is inoperative (condition 1), this allows the top to float, but secures the tonneau against movement.  
           [0011]    In this first valve position, operation of the pump in one direction will extend the top cylinders only (condition 2) to raise the top; it will pressurize one side of the tonneau cylinders, but they cannot move since the exhaust side is blocked. Pump operation in the other direction will retract the top cylinders only (condition 3) to lower the top; the tonneau cylinders are connected to exhaust, but cannot move since the pressure side is blocked.  
           [0012]    In a second valve position, both ends of the tonneau cylinders are connected to both sides of the pump, while one end of the top cylinders are connected to one side of the pump and the other top cylinder ends are blocked. If this position were used when the pump is inoperative, the tonneau would be unpressured and float, while the top would be secured against movement; however this condition is not desired and, consequently not utilized.  
           [0013]    In this second valve position, pump operation in one direction will extend the tonneau cylinders only (condition 4) to raise the tonneau. Operation of the pump in the other direction will retract the tonneau cylinders only (condition 5) to lower the tonneau. In both conditions 4 and 5, the blockage of one end of the top cylinders prevents their movement.  
           [0014]    These and other objects and features of this invention will become more readily apparent upon reference to the following detailed description of a preferred embodiment, as illustrated in the accompanying drawings, in which: 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIGS. 1 and 2 are perspective views of a convertible vehicle with its top shown in raised and lowered positions, respectively;  
         [0016]    [0016]FIG. 3 is a side view of one form of convertible top, having a movable rear bow, and illustrating the linkages and hydraulic cylinders used to control sequential movement of the top and the movable tonneau;  
         [0017]    [0017]FIG. 4 is a hydraulic schematic of the hydraulic cylinder control system, with the pump direction and control valve positioned to extend the top hydraulic cylinders and raise the top;  
         [0018]    [0018]FIG. 5 is a schematic similar to FIG. 4, is a hydraulic schematic of the hydraulic cylinder control system, with the pump direction and control valve positioned to retract the top hydraulic cylinders and lower the top;  
         [0019]    [0019]FIG. 6 is a schematic similar to FIGS. 4 and 5, but with the pump direction and control valve positioned to extend the tonneau hydraulic cylinders and raise the tonneau; and  
         [0020]    [0020]FIG. 7 is a schematic similar to FIG. 6, but with the pump direction and control valve positioned to retract the tonneau hydraulic cylinders and lower the tonneau. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]    This invention is directed to a top and tonneau operating system for the convertible top of a vehicle, such as the one disclosed in aforementioned U.S. Pat. No. 5,620,226. As shown in FIGS.  1 - 3  a convertible vehicle  20  includes a body  22  having a passenger compartment  24  that is enclosed by a windshield W, side windows S and a retractable top  26  that is selectively lowered into a storage compartment  28  behind passenger compartment  24 . A tonneau  30  covers storage compartment  28  when top  26  is lowered, and is selectively opened and closed, as later described, to permit raising and lowering of top  26 .  
         [0022]    As shown in FIG. 3, top  26  comprises a flexible cover C supported by a header H and transverse bows B 2 , B 3  and B 4 . The bows are supported at their sides by symmetrical articulated linkages  32  that pivotally support a movable rear, or # 5 , bow  34 . In the illustrated raised position of FIGS. 1 and 3, rear bow  34  rests upon and seals against tonneau  30 . Top  26  is raised and lowered by a pair of hydraulic cylinders  36 ,  36 ′, which have extensible output cylinder rods  38 ,  38 ′ that operate linkages  32  via a mechanical linkage  40  that also raises and lowers rear bow  34 .  
         [0023]    Tonneau  30  is opened and closed by a pair of hydraulic cylinders  42 ,  42 ′ that have extensible output cylinder rods  44 ,  44 ′. For the sake of simplicity, FIG. 3 illustrates only one side of the top and its operating system, since both sides are symmetrical. The top structure and operating system are more fully described in aforementioned U.S. Pat. No. 5,620,226.  
         [0024]    Referring now to the schematics in FIGS.  4 - 7 , top-operating hydraulic cylinders  36 ,  36 ′ have respective cylinder rods  38 ,  38 ′ that extend and retract to operate articulated linkages  32  to raise and lower top  26  and rear bow  34  via mechanical linkage  40 . Tonneau-operating hydraulic cylinders  42 ,  42 ′ each has a cylinder rod  44 ,  44 ′ that extend and retract to raise and lower tonneau  30 . Cylinders  36 ,  36 ′,  40 ,  40 ′ are all supplied with hydraulic power fluid from a power pack  50  that includes the usual reservoir of hydraulic fluid (not shown) that supplies a bi-directional pump  52  driven by an electric motor M.  
         [0025]    Pump  52  has one side connected to a fluid transfer line  54  which connects to a control unit  56  that includes a 2-position, 2-way valve  58 , that is operated by a solenoid  60  under direction of a controller C. Fluid in line  54  flows through a pilot-operated check valve  62  that is opened by pressure in a line  64  that connects to another fluid transfer line  66  connected to the other side of pump  52 .  
         [0026]    The right side of valve  58  includes a transfer bore  68  that connects to fluid line  70 , and a blocked port  72  that connects to fluid line  74  when valve  58  is in the FIGS. 4 and 5 positions. Pump line  66  connects to a distribution fluid line  76  for lines  78 ,  78 ′ that connect to the rod ends of top cylinders  36 ,  36 ′. Lines  80 ,  80 ′ connect the rod ends of tonneau cylinders  42 ,  42 ′ to distribution line  76 . With this arrangement, pump line  66  is always connected to the rod ends of all of cylinders  36 ,  36 ′ and  42 ,  42 ′. There is a fluid connection through check valve  62  and valve  58 , via line  70  and lines  82 ,  82 ′, between pump  52  and cylinder  36 ,  36 ′. Fluid in the blind ends of tonneau cylinders  42 ,  42 ′ through fluid lines  82 ,  82 ′ is trapped by port  72 .  
         [0027]    The left side of valve  58  includes a transfer bore  84  that connects to fluid line  74 , and a blocked port  86  that connects to fluid line  70  when valve  58  is in the FIGS. 6 and 7 positions. Line  74  connects through lines  88  and  88 ′ to the blind ends of tonneau cylinders  42 ,  42 ′, while the blind ends of top cylinders  36 ,  36 ′ are connected through lines  82 ,  82 ′ and line  70  to blocked port  86 . Again, with this arrangement, pump line  66  is always connected to the rod ends of all of cylinders  36 ,  36 ′ and  42 ,  42 ′. There is a fluid connection through check valve  62  and valve  58  between pump  52  and cylinder  42 ,  42 ′ blind ends via lines  74 ,  88 ,  88 ′, while fluid in the blind ends of cylinders  36 ,  36 ′ is trapped by port  86 .  
         [0028]    Top cylinder  36  is provided with extreme position limit switches  90  and  92  and intermediate limit switch  94  to monitor the position of the top cylinders. Tonneau cylinder  42  is provided with extreme limit switches  96  and  98  to monitor its position. These limit switches enable controller C to sequence operation of the hydraulic cylinders to open and close the tonneau and to raise and lower the top with appropriate raising and lowering of the rear bow in proper sequence. Intermediate limit switch  92  is necessitated by the use of the mechanical linkage  40  to control operation of the top cylinders to raise and lower rear bow  34  during top movement between raised and lowered positions, as more fully described in aforementioned U.S. Pat. No. 5,620,226.  
         [0029]    [0029]FIG. 4 depicts the position of valve  58  and direction of pump  52  to raise the top from its lowered and stored position. FIG. 5 depicts the position of valve  58  and condition of pump  52  to lower the top. FIG. 6 depicts the position of valve  58  and direction of pump  52  to raise the tonneau. FIG. 7 depicts the position of valve  58  and condition of pump  52  to lower the tonneau. Operation of the hydraulic system under conditions depicted in these drawing figures will now be described.  
         [0030]    In FIG. 4, pump  52  is in condition to supply pressure fluid to the system through line  54  and receive exhausted fluid through line  66  to raise top  26 . Of course makeup and excess fluid are transitioned through the sump or reservoir (not illustrated), as is usual. When commanded by controller C, pressure fluid is delivered through line  54 , check valve  62 , control valve  58 , bore  58 , line  70  and lines  82 ,  82 ′ to extend top cylinders rods  38 ,  38 ′. This forces fluid in the rod ends of cylinders  36 ,  36 ′ to exhaust through lines  78 ,  78 ′,  76  and  66  directly to pump  52 . Tonneau cylinder rods  44 ,  44 ′ are held in position by the fluid trapped in the cylinder blind ends which are connected via lines  88 ,  88 ′ and  74  to blocked port  74 . Only low exhaust pressure from top cylinders  36 ,  36 ′ is sensed by the rod ends of cylinders  42 ,  42 ′ via lines  80 ,  80 ′. As cylinder rods  38 ,  38 ′ extend, top  26  rises out of storage compartment  28 .  
         [0031]    In FIG. 5, pump  52  is reversed to supply pressure fluid to the system through line  66  and to receive exhaust fluid through line  54  via valves  58  and  62  to lower top  26 . Controller C commands delivery of pressure fluid to line  66 . This causes pressurization of pilot line  64  to open check valve  62 . Pressure fluid flows through line  76  to the rod ends of top cylinders  36 ,  36 ′ via lines  78 ,  78 ′, and to the rod ends of tonneau cylinders  42 ,  42 ′ via lines  80 ,  80 ′. The blind ends of top cylinders  36 ,  36 ′ connect back to pump  52  via lines  82 ,  82 ′ and  70 , valve bore  68  and check valve  62  (held open by pilot pressure) and line  54 . Fluid is trapped in the blind ends of cylinders  42 ,  42 ′ since outflow through lines  88 ,  88 ′ is blocked by blocked port  72 . Thus, tonneau cylinders  42 ,  42 ′ are prevented from retracting to close tonneau  30 , despite pressure in their rod ends. As cylinder rods  38 ,  38 ′ retract, top  26  lowers into storage compartment  28 .  
         [0032]    In FIG. 6, pump  52  is again reversed to pressurize line  54 , while solenoid  60  is commanded to shift valve  58  rightward to flow fluid through check valve  62 , valve bore  84 , and lines  74 ,  88  and  88 ′ to the blind ends of tonneau cylinders  42 ,  42 ′ to extend cylinder rods  44 ,  44 ′ and raise tonneau  30 . Outflow from the tonneau cylinder rod ends is through lines  80 ,  80 ′ and  66  to pump  52 . Top cylinders  36 ,  36 ′ are locked against movement by blockage of any outflow of fluid from their blind ends, because lines  82 ,  82 ′ connect to blocked port  86  in valve  58 , and fluid in their rod ends are subject to exhaust pressure in lines  76 ,  78  and  78 ′. As cylinder rods  44 ,  44 ′ extend, tonneau  30  rises to permit passage of top  26  between raised and lowered positions.  
         [0033]    In FIG. 7, pump  52  is again reversed to pressurize line  66 , and pressurize pilot line  64  to open check valve  62 . Pressure fluid flows through lines  66 ,  76 ,  80  and  80 ′ to the rod ends of cylinders  42 ,  42 ′ to retract cylinder rods  44 ,  44 ′. Fluid outflow from the blind ends of the tonneau cylinders is through lines  88 ,  88 ′ and  74 , through valve bore  84  and now-open check valve  62  and line  54  to pump  52 . Top cylinders  36 ,  36 ′ are immobilized by trapped fluid in their blind ends, which connect through lines  82 ,  82 ′ to blocked valve port  86 , even though the rod ends are pressurized via lines  76 ,  78  and  78 ′. Retracting cylinder rods  44 ,  44 ′ lower tonneau  30  to close storage compartment  28 .  
         [0034]    Operation of the top operating hydraulic control system will now be described during the raise/lower cycle of the convertible top through sequential movement of the top and tonneau cylinders, beginning with the top in lowered position within storage compartment  28  with tonneau  30  closed (FIG. 2).  
         [0035]    The hydraulics will initially be in the FIG. 6 position. Pump  52  is commanded to pressurize line cylinders  42 ,  42 ′ through line  54 , valves  62  and  58  and lines  74 ,  88  and  88 ′ to extend cylinder rods  44 ,  44 ′ and raise tonneau  30 .  
         [0036]    Next, valve  58  is shifted and the hydraulics are in the FIG. 4 position, with the blind ends of top cylinders  36 ,  36 ′ pressurized via line  54 , valves  62  and  58  and lines  70 ,  82  and  82 ′ to extend cylinder rods  38 ,  38 ′ to initially raise top  26  and then to raise rear bow  34 , as more fully detailed in aforementioned U.S. Pat. No. 5,620,226.  
         [0037]    The hydraulics then assume the FIG. 7 position via reversal of pump  52 , which now pressurizes the tonneau cylinder rod ends via lines  66 ,  80  and  80 ′ to retract rods  44 ,  44 ′ and lower tonneau  30 . The hydraulics are then shifted to the FIG. 5 position by shifting valve  58 . This pressurizes the rod ends of top cylinders  36 ,  36 ′ via lines  66 ,  76 ,  78  and  78 ′ to partially retract cylinder rods  38 ,  38 ′ to lower rear bow  30  is lowered as sensed by limit switch  94  which causes controller C to stop pump  52 .  
         [0038]    When it is desired to lower the top, pump  52  is reversed to the FIG. 4 position to fully extend cylinder rods  38 ,  38 ′ and again raise rear bow  30 . Then valve  58  is shifted to the FIG. 6 position and tonneau  30  is raised. Next, pump  52  is reversed and valve  58  is shifted to the FIG. 5 position and top  26  is lowered. Then valve  58  is shifted to the FIG. 7 position to lower tonneau  30 . Top  26  is raised by reversing the above procedure.  
         [0039]    While only a preferred embodiment has been described and shown, obvious modifications are contemplated within the scope of this invention and the following claims.