Patent Publication Number: US-6666487-B2

Title: Power striker with toggle linkage drive mechanism

Description:
This application claims benefit to provisional application No. 60/184,890 filed Feb. 25, 2000. 
    
    
     FIELD OF INVENTION 
     The subject invention relates to a power striker for use in a motor vehicle. In particular, this invention relates to a striker having an actuator for cinching a closure panel from an initial latched position to a final latched position. 
     BACKGROUND OF THE INVENTION 
     A vehicle closure panel, such as a door, typically includes a seal to prevent exterior environmental elements from intruding into a passenger compartment. The seal also reduces the amount of exterior noise transmitted into the passenger compartment. Seals with higher stiffness and greater seal pressures are being used to accommodate consumer demand for a quieter passenger compartment. In other words, new seals are becoming much stiffer than those traditionally used. As appreciated, a stiffer seal translates into an increase in force required to completely close the vehicle closure panel. 
     One solution to this problem is the use of a power striker. In one type of power striker, the latching mechanism of the vehicle closure panel latches to a striker mounted on the vehicle body. The closure panel is then closed to an initial closed position, the striker is then powered inboard by an actuator that cinches the closure panel to a final closed position. 
     One shortcoming of such a mechanism is its vulnerability to damage by slamming of the closure panel. A slamming closure panel damages the striker by driving the striker inboard of the vehicle. If the actuator is directly linked with the striker, the forces are exerted on the striker are transmitted through the drive mechanism to the actuator, damaging the actuator. Repair and replacement of these types of mechanisms is complicated due to the confined mounting locations required of such mechanisms. 
     SUMMARY OF INVENTION 
     The disadvantages of the prior art may be overcome by providing a power striker mechanism having a housing adapted for mounting on a vehicle. A striker assembly is mounted to the housing and constrained to slide between an inboard and outboard position. An outer link is pivotally attached to the striker assembly. An inner link is pivotally attached to the housing. A cinching mechanism linkably connects the inner and outer links. Driving movement of the cinching mechanism effects the inboard and outboard movement of the striker assembly. The driving movement is generally perpendicular to the inboard outboard movement of the striker assembly thereby isolating the cinching mechanism from loads imparted to the striker assembly. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
     FIG. 1 is a perspective front view of a power striker mechanism of the present invention; 
     FIG. 2 is a perspective view of a striker assembly of the mechanism of FIG. 1; 
     FIG. 3 is an exploded perspective rear view of the striker assembly of FIG. 2 mounted within a housing; 
     FIG. 4 is a perspective rear view of the power striker mechanism of FIG. 1 in an extended position; 
     FIG. 5 is a perspective rear view of the power striker mechanism of FIG. 1 in a cinched position; 
     FIG. 6 is a perspective rear view of a power striker mechanism of a second embodiment; and 
     FIG. 7 is perspective rear view of the power striker mechanism of FIG. 6, with the rear plate removed. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the Figures wherein like numerals indicate like or corresponding parts throughout the several views, a power striker mechanism is generally shown at  10  in FIG.  1 . 
     The power striker mechanism  10  includes a striker assembly  12  disposed within a housing  16 . The housing  16  has a top portion  15  and a bottom portion  17 . The striker assembly  12  includes a striker loop  34  that extends through the housing  16 . In particular, the striker loop  34  extends through a rectangular slot in a front side of the housing  16 . 
     The striker loop  34  also extends through a rectangular slot in a cover plate  40  that attaches to the sheet metal of the vehicle once the striker is installed. The cover plate  40  provides a means for attaching a seal (not shown) between the vehicle body and the power striker mechanism  10 . 
     As discussed in greater detail below, arrows A and B illustrate inboard and outboard directions of movement of the striker loop  34 . As appreciated, the particular direction of the inboard and outboard movement is dependent on the orientation of the striker mechanism  10 . 
     Attached to the bottom portion  17  of the housing  16  is a drive housing  56 . Mounted to the drive housing  56  is a planetary gear box  20  and a motor or actuator  22 . Motor  22  provides a driving rotation through gear box  20  to drive screw  18 . Motor  22  and gear box  20  are conventional in design. Any suitable arrangement of motor and gear box will provide adequate results. Design criteria for a maximum seal load of 750 N requires a peak torque output of about 360 Nmm and for a maximum seal load of 1000 N requires a peak torque output of about 440 Nmm. It is well within the purview of those skilled in the art to provide a motor and gear box combination to produce the desired outputs. 
     In addition, the motor  22  could be mounted remotely from the housing  16  and operatively connected by a flexible drive cable which is commonly used in automotive applications. 
     Referring to FIG. 2, the striker assembly  12  comprises an elongate base plate  24  having a rectangular shape with two holes  26  disposed therein. The base plate  24  has a slot  28  in which a drive pin  30  is slidably mounted. The drive pin  30  is mounted in the slot  28  to allow slight inboard and outboard movement relative to the base plate  24 . A resilient energy absorber  32  is mounted in the slot  28 . The energy absorber  32  limits outboard movement of the drive pin  30  relative to the base plate  24  within the slot  28 . 
     The striker loop  34  extends through the two holes  26  and attaches to the base plate  24  by any suitable fastener or attachment means. The base plate  24  is slidingly constrained by a pair of C-shaped slide bearings  36 . The slide bearings  36  slidingly receive base plate  24  to allow only inboard movement as shown by arrow A, and outboard movement as shown by arrow B. 
     Referring to FIG. 3, the striker assembly  12  is shown mounted within the housing  16 . The housing  16  is configured to receive slide bearings  36  and based plate  24 . The striker assembly  12  is secured to the housing  16  by a retainer plate  38 . The retainer plate  38  is secured within the housing  16  by three mounting screws (not shown). 
     Referring to FIGS. 4 and 5, the power striker mechanism  10  also includes a cinching mechanism  14  disposed within the housing  16  and operably connected to the striker assembly  12 . The cinching mechanism  14  comprises an outer link  42  pivotally attached to the housing  16  at a pin  44 , defining a second pivot. The retainer plate  38  provides a mounting point for the outer link  42 . 
     An inner link  48  is pivotally attached at a first end to outer link  42  by connection pin  46  defining a third pivot and at a second end to the drive pin  30  defining a first pivot. 
     A driving link  50  is pivotally attached at a first end to the connection pin  46  and at a second end to a clevis  54  at a clevis pin  52 . Clevis  54  has a shaft  55  which has an external thread. 
     Screw shaft  18  has a threaded bore in the end of the shaft. The clevis  54  threadingly engages into screw shaft  18 . Rotation of the screw shaft  18  effects movement of the clevis  54 . The motor  22 , through gearbox  20 , provides driving rotational movement of screw shaft thereby effecting movement of the clevis  54  in a direction perpendicular to the inboard and outboard movement. The screw shaft  18  is journal mounted within the drive housing  56  that supports the planetary gearbox  20 . Threads (not shown) on the screw shaft  18  convert the rotary motion of the planetary gearbox  20  to linear vertical motion of the clevis  54 . Screw shaft  18  also constrains the movement of the clevis  54  to linear movement. 
     As is now apparent to those skilled in the art, there are many existing methods of achieving linear motion of the clevis  54 . 
     Referring in particular to FIG. 4, the striker loop  34  is in an outboard position (shown by arrow B) such that the driving link  50  is urged to a downward position by the clevis  54 . The third pivot (connection pin  46 ) will be out of alignment with the first pivot (drive pin  30 ) and the second pivot (pin  44 ). In this outboard position, the linear distance between the fixed pin  44  and the drive pin  30  is at a minimum. 
     An impact of the vehicle closure panel on the striker loop  34  in the inboard direction (shown by arrow A) will be transmitted to the base plate  24  and partially absorbed by the energy absorber  32  positioned within the slot  28  before being transmitted to the drive pin  30 . The energy absorber  32  dissipates much of the force exerted on the striker loop  34  by providing a pliant medium between the base plate  24  and the drive pin  30 . 
     In other words, the resiliency of energy absorber  32  reduces the magnitude of impact forces transmitted into the cinching mechanism  14  from the slamming of the vehicle closure panel. Any remaining forces will be transmitted through the drive pin  30 , to the inner link  48 , and to the connection pin  46 . Forces at the connection pin  46  will be further transmitted to both the outer link  42  and the driving link  50 . Forces on the outer link  42  will be transmitted to the retainer plate  38  and further onto the vehicle body. Forces exerted onto the outer link will be transmitted through clevis pin  52  will not be transmitted into the planetary gearbox  20  due to the threaded engagement between the screw shaft  18  and the clevis  54 . Specifically, back driving forces from the striker loop  34  will not enable the screw shaft  18  to rotate as a result of thread pitch selection of the threads on the screw shaft  18 . The subject invention therefore protects the gears of the planetary gearbox  20  from the impact forces of a slamming closure panel. 
     Referring in particular to FIG. 5, the cinching mechanism  14  moves the striker loop  34  (hidden from view in FIG. 5) from the outboard position to an inboard position to pull the vehicle closure panel to a final closed or cinched position. Actuator  22  is energized to rotate the planetary gearbox  20  and the screw shaft  18 . The screw shaft  18  drives the clevis  54  toward the top  15  of the housing  16 . The movement of the clevis  54  pushes the connection pin  46  upward into alignment with the fixed pin  44  and the drive rivet  30 . As appreciated, with the outer  42  and inner  48  links in alignment, the fixed pin  44  (the second pivot) and drive pin  30  (first pivot) will be at a maximum linear distance and in general alignment. With the closure panel in the fully inboard position, the cinching mechanism  14  locks the striker loop  34  into position. The energy absorber  32  within the slot  28  of the base plate  24  will absorb imparted inboard forces on the striker loop  34 . Remaining forces will be transmitted to the vehicle body and will not be directed through the drive link  50 . 
     As the inner  48  and outer  42  links come into alignment, the mechanical advantage becomes infinite. The use of this “toggle” mechanism is key to overcoming high seal forces with a relatively small power input motor. 
     Referring to FIGS. 6 and 7, a power striker mechanism  60  of a second embodiment of the present invention is illustrated. The second embodiment is identical to the first embodiment, except that the power striker mechanism has a thumbwheel  66  operatively mounted on the screw shaft  18 . A rear plate  62  covers the rear of drive screw housing  56 . Rear plate  62  has a slot  64  through which thumbwheel  66  extends. Manual rotation of the thumbwheel  66  effects the inboard and outboard movement of the striker loop  68 . Optionally, the gear box of this embodiment can be provided with a clutch to allow counter rotation of the drive screw  18  and minimize back drive efforts. 
     The invention has been described in an illustrative manner, and it is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that the invention may be practiced otherwise than as specifically described.