Abstract:
A four-bar linkage hinge having a restraining catch arranged to prevent the hinge from opening and translating rearward when said hinge is subjected to an external force causing a transverse deflection of its linkage.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an improved four-bar linkage hinge arrangement, and, more particularly, to a restraining device for a four-bar linkage hinge that becomes operational to restrict the hinge from opening in response to a generally transverse deflection of the first bar relative to the second bar of the hinge. 
     BACKGROUND OF THE INVENTION 
     A motor vehicle generally has a number of closable and latching exterior aperture covers. The vehicle generally includes a hood to cover the engine and prevent dust and moisture from entering the engine compartment, as well as a lid for the trunk. In order to open the hood or access the trunk, the respective cover generally employs a hinge arrangement, spring assisted or otherwise, designed to assist an operator in lifting and securing one end of the cover in an open position. Typically, single pivot hinge arrangements are used in these applications. Single pivot arrangements, however, can be limited by their construction and/or packaging constraints of a vehicle body. Typically, when a cover equipped with a single pivot hinge is raised, the cover&#39;s front portion will rise, while the portion to the rear of the linkage will generally dive, i.e. drop below its starting position. In vehicles with tight packaging constraints, such hinge-imposed motion may result in the rear portion of the cover interfering with other portions of the vehicle body, which is undesirable. 
     A four-bar linkage hinge provides a solution for dealing with such space-restricted packages. The four-bar linkage hinge has two pivoting bars linking an upper bar which mounts to the cover and a lower bar which mounts to the vehicle body. In operation the four-bar linkage generates a compound motion of rotation and vertical translation. As generally configured for use with a vehicle hood the linkage&#39;s compound motion is disproportionate in favor of vertical translation. Such configuration is typically chosen to prevent the portion of the hood to the rear of the linkage from diving below its starting position and into the body structure when the hood is raised. With this type of articulation, however, an angled frontal impact force on the vehicle body may drive the hood rearward and transversely with respect to the vehicle centerline, thereby causing the rear portion of the hinge, and particularly the rear corner of the hood, to lift or move upwardly and translate toward the vehicle&#39;s passenger compartment. 
     It would be desirable to provide a four-bar linkage hinge that can open during regular operation, but whose rear portion would be restrained from lifting up and translating rearward when the linkage is subjected to a transverse deflection. 
     SUMMARY OF THE INVENTION 
     The present invention is a four-bar linkage hinge with a catch for restraining its movement in response to a transverse deflecting force. The linkage has a first bar, a second bar, a third bar pivotably connected at a first point to the first bar and at a second point to the second bar, and a fourth bar pivotably connected at a third point to the first bar and at a fourth point to the second bar. The restraining catch is attached to the third bar at a predetermined position between the first point and the second point and arranged to engage the first bar in response to a generally transverse deflection of the first bar relative to the second bar. 
     The four-bar linkage hinge of the present invention is particularly well suited for mounting an engine compartment cover or hood to a body of a motor vehicle. The four-bar linkage hinge has the first bar for attaching to the hood and the second bar for attaching to the vehicle body. The third bar and the fourth bar pivotably connect the first bar and second bar, thereby facilitating the opening and closing of the hood. The restraining catch is attached to the third bar at a predetermined position whereby, when the hinge is in a closed position, the restraining catch will engage the first bar in response to a generally transverse deflection of the first bar relative to the second bar. Such transverse deflection may result, for example, from an impact on a frontal corner of the hood. 
     In practice, the restraining catch extends upwardly through an aperture or opening in the upper bracket when the hood is in a closed position and clears the aperture when the hood is opened during the normal operation of the hinge. In the event of a frontal corner impact on the vehicle, transverse movement of the first bar causes the restraining catch to engage the aperture which in turn prevents the hinge from opening and translating the hood rearward. 
     It should be understood that the detailed description and specific examples which follow, while indicating preferred embodiments 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 
         FIG. 1  is a perspective view of a typical four-bar linkage hinge shown in an open position connecting a motor vehicle hood to the vehicle&#39;s body according to prior art. 
         FIG. 2  is a perspective view of a left-hand four-bar linkage hinge in a closed position illustrating a restraining catch according to the invention. 
         FIG. 3  is a perspective view of the four-bar linkage hinge shown in  FIG. 2  wherein the restraining catch and the third bar comprise a unitary structure. 
         FIG. 4  is a perspective view of the four-bar linkage hinge shown in  FIG. 2  in an open position connecting a motor vehicle hood to the vehicle&#39;s body. 
         FIG. 5  is a perspective view of a four-bar linkage hinge according to the invention positioned normally within a vehicle body. 
         FIG. 6  is a perspective view of the four-bar linkage hinge shown in  FIG. 5  wherein the vehicle hood has been deflected transversely and the restraining catch has engaged the aperture. 
         FIG. 7  is a perspective view of the four-bar linkage hinge shown in  FIG. 5  wherein the vehicle hood has been deflected transversely with the restraining catch received in the aperture and engaged with the linkage bar in which the aperture is disposed. 
     
    
    
     DETAILED DESCRIPTION 
     In general the present invention is directed to a four-bar linkage hinge with a restraining catch. Although the hinge can have many applications, in practice, it will be described hereinafter with respect to its use and operation in connection with a motor vehicle hood. 
     Referring now to the drawings, like elements of the invention are identified with identical reference numerals throughout.  FIG. 1  is a perspective view of a typical four-bar linkage hinge according to the prior art shown connecting vehicle hood  10  is attached to vehicle body  20  via four-bar linkage hinge  30 . Hinge  30  is comprised of first bar  31  fixed to vehicle hood  10  at points  41  and  42 , and second bar  32  fixed to vehicle body at points  43  and  44 . Third bar  33  is pivotably connected to first bar  31  at point  51  and to second bar  32  at point  52 , and fourth bar  34  is pivotably connected to first bar  31  at point  53  and to second bar  32  at point  54 . Hinge  30  is typically fixed to vehicle hood  10  at points  41  and  42  and to vehicle body  20  at points  43  and  44  with threaded fasteners (not shown). Second bar  33  and third bar  34  are typically pivotably connected to bars  31  and  32  with rivets. The four bars comprising four-bar linkage hinge  30  are made from a rigid material, such as steel, to withstand regular loads imposed from opening and closing of a vehicle hood. 
     Hinge  30  according to the present invention is best seen in  FIGS. 2-7 .  FIG. 2  is a perspective view of hinge  30  in a closed position. Four-bar linkage  30  includes first bar  31  having aperture  60 , and third bar  33  having restraining catch  70 . Restraining catch  70  may be mounted to third bar  33  with a threaded fastener (not shown) or catch  70  may be integrally formed with bar  33  and comprise a unitary structure (shown in  FIG. 3 ). Restraining catch  70  is an elongated rigid bar preferably made from steel, but may also be made from a reinforced engineering plastic or other high strength material. Restraining catch  70  has a free end terminating in a hooked offset  75  positioned to clear aperture  60  when first bar  31  is vertically aligned relative to second bar  32  during normal operation of opening ( FIG. 4 ) and closing ( FIG. 5 ) of hinge  30 . 
     With a typically configured four-bar linkage hinge  30  as employed in a motor vehicle, a frontal impact force on the corner of the vehicle body that is translated to the vehicle hood can result in significant transverse movement of first bar  31  relative to second bar  32 . Such transverse movement may cause the linkage, and with it the rear edge of the hood, i.e. the edge closest to the vehicle&#39;s passenger compartment as best seen in  FIG. 1 , to lift up and translate rearward toward the passenger compartment. When hinge  30  is in the closed position, hooked offset  75  is positioned to engage first bar  31  at aperture  60  in response to a generally transverse deflection of the first bar relative to second bar  32 , i.e. in response to a frontal impact on the hood. 
     As shown in  FIGS. 6 and 7 , restraining catch  70  engages aperture  60  and thereby prevents the hood&#39;s rear portion from lifting up and translating rearward, i.e. first bar  31  and second bar  32  become physically tied together when the first bar is subjected to a transverse deflection relative to the second bar. By engaging aperture  60  with hooked offset  75 , restraining catch  70  channels frontal impact forces which might otherwise drive the rear edge of the hood up and rearward toward the passenger compartment into the vehicle&#39;s body structure. 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.