Abstract:
A vehicle having a suspension system that supports a vehicle frame has a suspension interlock for governing the distance that the suspension system may move away from the frame during a vehicular rear impact event, thereby channeling impact forces through the suspension system and into the vehicle frame. A flexible member attaches to the vehicle frame and to the suspension system and acts as a tether to maintain the position of the suspension system relative to the frame. Alternatively, the suspension interlock may be a u-shaped bar mounted to the vehicular frame that interacts with a pin that is mounted to the suspension system. The pin resides within the confines of the u-shaped bar to maintain the position of the suspension system relative to the frame. Alternatively, a hooked plate may be used instead of a pin.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a vehicular suspension interlock system to restrain suspension travel during a rear impact event.  
       BACKGROUND OF THE INVENTION  
       [0002]     Modern automotive vehicles typically have impact absorbing devices located in their rear areas to absorb impact forces and also channel impact forces into the vehicle frame during a vehicular rear impact event. In addition to the impact absorbing devices, vehicles may be equipped with rear suspension devices that usually do not function in conjunction with the rear impact absorbing devices during a rear impact event. While current impact absorbing devices have proven satisfactory for their applications, each is associated with its share of limitations. One limitation with rear impact absorbing devices is that they are designed to absorb all or most of the impact forces experienced by the rear of the vehicle during a rear impact. Another limitation is that current rear impact absorbing devices do not channel impact forces to other rear areas of the vehicle structures to utilize the impact absorbing capabilities of other rear area structures during a vehicular rear impact.  
         [0003]     What is needed then is a device that does not suffer from the above limitations. This, in turn, will provide a vehicular device that, during a rear impact event, works in conjunction with the rear impact absorbing devices and channels the force of impact through additional areas of the vehicular frame.  
       SUMMARY OF THE INVENTION  
       [0004]     A suspension interlock system for a vehicle having a rear suspension system that supports a vehicle frame further secures the rear suspension system to the vehicle frame. To secure the rear suspension system to the vehicle frame, the suspension interlock system may be a flexible member attached to the vehicle frame and the rear suspension system or a u-shaped bar attached to the vehicular frame that surrounds a pin attached to the rear suspension system.  
         [0005]     Further areas of applicability of the present invention will, become apparent from the detailed description provided hereinafter. 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  
       [0006]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0007]      FIG. 1  is a side view of a rear suspension depicting the placement of a suspension interlock device of a first embodiment of the present invention;  
         [0008]      FIG. 2  is a side view of a rear suspension depicting the placement of a suspension interlock device of a second embodiment of the present invention;  
         [0009]      FIG. 3  is a perspective view of a rear suspension depicting the location of a suspension interlock system in front of the rear axle according to a third embodiment of the present invention;  
         [0010]      FIG. 4  is a side view of the rear suspension interlock system of  FIG. 3 ;  
         [0011]      FIG. 5  is a perspective view of a hook and loop arrangement of a suspension interlock system according to a fourth embodiment of the present invention;  
         [0012]      FIG. 6  is a side view of the hook and loop arrangement according to the fourth embodiment of the present invention;  
         [0013]      FIG. 7  is a side view of the suspension interlock system prior to a vehicular rear impact; and  
         [0014]      FIG. 8  is a side view of the suspension interlock system during a rear impact event. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Turning first to  FIG. 1 , the components of a first embodiment of the suspension interlock system will be explained. The suspension interlock system  10  of a first embodiment is primarily composed of an interlock cable  12 , a vehicular frame rail  14  and a trailing link bracket  16 . The interlock cable  12  may be a cable with a circular cross-section sufficient in strength to achieve its purpose, which will be described later. The interlock cable  12  may be made from any one of a variety of materials, such as steel, titanium, etc. that are capable of providing sufficient strength. The cable  12  could also be a blend of metals or a non-metal material such as Kevlar.  
         [0016]     A first end of the cable  12  is connected to the frame rail  14  by a fastener, such as a bolt  18 ; however, any acceptable fastening means may be used, including but not limited to, a rivet, a screw, or welding the cable  12  to the frame rail  14 . The trailing link bracket  16  secures an end of the upper trailing link  20  and an end of the lower trailing link  22  of the suspension system  24 . The opposite ends ( FIGS. 7 and 8 ) of the links  20 ,  22  may be fixed to the frame rail  14  with brackets. Similarly to the first end of the cable  12 , the second end of the cable  12  is attached to the trailing link bracket  16  by a bolt  30 ; however, any acceptable fastening means can be used, such as rivets, screws, welding, etc.  
         [0017]     The suspension system  24  also entails a coil spring  26  that abuts against and attaches to the frame rail  14 . The coil spring  26  works in conjunction with a shock absorber  28  to provide the proper support to the frame  14 , and thus, the vehicle in which the suspension system  24  is installed. One end of the shock absorber  28  may be attached to a shock bracket  29 , while the other end of the shock absorber  28  may be attached to the frame  14 . The shock bracket  29  may also be attached to, or integrally a part of, the trailing link bracket  16 .  
         [0018]     In a second embodiment of the present invention, depicted in  FIG. 2 , a flat strap  32  is employed instead of the round cable  12  of the first embodiment. Because the flat strap  32  has an elongated oval or square cross-section, an advantage of the flat strap  32  over the round cable  12  is its potential to be folded into a more compact package, and its potential to flex in predictable directions, such as along the longer of its flat edges, when viewed in cross-section. Since the flat strap  32  may be predicted to fold and flex in certain directions, it may be packaged within a suspension system more advantageously. That is, because certain vehicles may have limited space within which to place such a suspension restraint, the flat strap  32  may be more advantageous than other cables or other restraint options. Additionally, the flat strap  32  may provide more advantageous mounting against the flat frame rail  14  because the flat strap  32  also has a wider, flat surface to provide a slimmer, lower-profile mount with comparatively more surface area than a circular cable. However, it is conceivable that either the circular cable  12  or the flat strap  32  may be secured into a mounting tab  33  before the mounting tab  33  is secured to the frame rail  14 . By using a mounting tab  33 , securing either the circular cable  12  or the flat strap  32  to the frame rail  14  may be performed in a more consistent fashion.  
         [0019]     Turning to  FIG. 3 , the present invention according to a third embodiment is depicted.  FIG. 3  only depicts pertinent portions of the third embodiment of the suspension interlock system and omits other, unnecessary portions of the vehicle in exhibiting the operative workings of the third embodiment.  FIG. 3  depicts the trailing link bracket  16  mounted to the vehicle axle  48  and shows the upward direction  50  and downward direction  52  that the axle  48  may move when a vehicle is in use or undergoes a rear impact event. Also depicted is a loop  42  and pin  46  arrangement. The loop  42  is attached to the frame rail  14  by an acceptable means such as by using a bolted bracket (not shown) to secure the loop  42  to the frame rail  14 , by welding, etc. When the vehicle is in use, the vehicle axle  48  moves upward and downward such that the securing pin  46  moves within the confines of the loop  42  and frame rail  14 . The significance of the pin  46  remaining within the confines of the loop  42  and the frame rail  14  will be discussed later. Additionally, the pin plate  44 , to which the pin  46  is attached to, may be secured to the axle  48 .  
         [0020]      FIG. 4  is a side view of the third embodiment of the suspension interlock system  40 . In the side view of  FIG. 4 , the rear wheel (not shown) is removed to permit viewing of components of the suspension interlock system  40 . The loop  42  is shown to possess a front bar  41  and a rear bar  43 . Additionally, the loop  42  and pin  46  are located in front of the axle; however, the loop  42  and pin  46  could be located behind the axle  48  or even over the axle  48  depending upon the packaging requirements of the vehicle in which the suspension interlock system  40  is installed.  
         [0021]      FIG. 5  is a perspective view of a fourth embodiment of a suspension interlock system  60  of the present invention. The suspension interlock system  60  of the fourth embodiment includes a loop  66  that may be a steel bar loop that is generally formed of an outside bar  70  and an inside bar  68 . The outside bar  70  has a hook  72  that may be used for mounting purposes. Generally, the loop  66  mounts between the frame rail  14  and the bracket  74 , which holds the loop  66  in place during its use as a suspension interlock device. The plate  62  has a hook  64  that is located between the inside bar  68  and outside bar  70 . The hook  64  is permitted to travel within the confines of the loop  66  with the loop acting as a restraining device to prevent the hook  64  portion of the plate  62  from moving beyond the confines of the loop  66 . Because the plate  62  is attached to components of the vehicle suspension system, the hook  64 , plate  62  and loop  66  prevent the suspension system from separating from adjacent the vehicle frame  14 . The plate  62  may be mounted to the trailing link bracket  16 , axle  48 , or other suitable component.  
         [0022]      FIG. 6  is a side view of the suspension interlock system  60  of the fourth embodiment of the present invention.  FIG. 6  depicts the positional relationship of the inside bar  68 , outside bar  70 , the plate  62 , and plate hook  64 . As shown, the plate hook  64  protrudes from the plate  62  such that the plate hook  64  passes through the loop  66 . The bracket  74  secures the inside bar  68  and outside bar  70  from moving away from the frame rail  14 . Although shown secured with a bracket  74 , the inside bar  68  and outside bar  70  may be secured by welding the bars  68 ,  70  to the frame rail  14 .  
         [0023]     The operative workings of the various embodiments of the present invention will now be presented.  FIGS. 7 and 8  depict the rear of a vehicle  93  in which the suspension interlock system  60  depicted in  FIGS. 5 and 6  is invoked; however, the operative workings of the various embodiments are similar and the effects of the various embodiments are designed to be equal. In explaining the operative workings as they relate to  FIGS. 5 and 6 , the operative workings of the other embodiments may be presented.  FIGS. 7 and 8  depict a load  90  that possess a force represented by force arrow  92 . The load  90  and force are directed toward the rear of the vehicle  93 . The load  90  is representative of an impacting vehicle that may strike the rear end of the vehicle  93  in a rear impact event of the vehicle  93 .  FIG. 7  depicts the upper trailing link  20  and lower trailing link  22  in their pre-impact, horizontal positions. The axle  48  is positioned between the upper trailing link  20  and lower trailing link  22 . At each end of the axle  48  a wheel  97  is attached. The differential  94  is shown protruding rearward of the axle  48 , both of which are positioned adjacent the spare wheel  96 . Although a spare wheel  96  is described, the spare wheel  96  location could also be occupied by a spare wheel container, a storage recession in the rear floor of the vehicle  93 , or other object that might occupy the space depicted as a spare wheel  96 .  
         [0024]     As depicted in  FIG. 8 , when the load  90  strikes the vehicle  93  at impact location  98  during a rear impact event as an example, the frame rail  14  is affected by a force, as depicted with force arrow  100 , while the spare wheel  96  is affected by a force, as depicted with force arrow  102 . The force arrows  100 ,  102  are the transfer and absorption of the load force of load  90 . The force of impact  92  causes the spare wheel  96  to be directed into the rear axle assembly  104 , namely the differential  94 , the rear axle  48 , and rear suspension links  20 ,  22 . When the spare wheel  96  meets the rear axle assembly  104 , the impact force of such meeting causes the rear axle assembly  104  to begin pivoting about pivot point  106  of the upper trailing link  20 , and pivot point  108  of the lower trailing link  22 . The pivoting about pivot points  106 ,  108  is due to a downward force acting on the upper trailing link  20  and lower trailing link  22  from the force  102  acting on the differential cover  94 , rear axle  48 , and other rear suspension components.  
         [0025]     As the spare wheel  96  force  102  acts on the rear axle assembly  104 , forces act concurrently through the upper trailing link  20  as shown by force  110  and lower trailing link  22  as force  112 . The forces in the trailing links  20 ,  22  are immediately transferred into the frame rail  14 , the process of which will now be explained.  
         [0026]     The forces resulting from the load  90  impact are initially divided between the frame rail  14  and the spare wheel  96 . An advantage of the present invention is that the force that impacts the spare wheel  96  is then transferred into the frame rail  15  in a more forward position in front of the rear axle assembly  104  through the rear suspension components such as the upper trailing link  20  and lower trailing link  22 . By dividing and transferring the impact force from force arrow  92  to both force arrow  100  and force arrow  102 , the force of impact is more evenly distributed than if the frame rail  14  completely absorbs all of the impact. By dividing the force, the impact load subjected to the frame rail  14  aft of the rear axle assembly  104  is lessened. This permits more of the load  90  to be absorbed by more of the vehicle structure, more specifically, the frame rail  15  in front of the rear suspension instead of that part of the frame rail above the spare wheel  96 . Without the suspension interlock system of the present invention, the frame rail  14  above the spare tire  96  absorbs all of the impact forces from the rear impact. This may cause the frame rail  14  to buckle as the rear suspension components move away from the frame rail  14  due to the impacting forces. Generally, the rear suspension components and rear axle assembly  104  are not able to absorb the rear impact forces when they separate from the frame rail  14  during a rear impact.  
         [0027]     To accomplish this force distribution, the suspension interlock system depicted in  FIGS. 7 and 8  will be explained. When the load  90  strikes the rear end of vehicle  93 , the frame rail  14  may begin to buckle upwards in accordance with direction arrow  99 . As the load  90  continues moving into the rear of the vehicle  93 , the load strikes the spare wheel  96 , which may be forced into the rear axle assembly  104 . When the rear axle assembly  104  makes contact with the load  90 , the rear axle assembly  104  begins moving downward according to arrow  101 , which invokes the suspension interlock system  60 .  FIGS. 7 and 8  do not show the relative repositioning of the frame  14  and rear wheel  96 . Instead, the result of such repositioning is reflected in the rear axle assembly  104 .  
         [0028]     With reference to  FIGS. 5-8 , the inside bar  68  and outside bar  70 , together with the frame rail  14 , contain the hook  64  of plate  62 . Upon the impact of load  90 , the inside bar  68  and outside bar  70  remain attached to, and move in conjunction with, the frame rail  14 . The hook  64 , which protrudes from the plate  62 , begins moving downward in accordance with arrow  101  as the rear axle assembly  104  begins pivoting downward, which is also clockwise in  FIG. 8 , about pivot points  106 ,  108 . As the rear axle assembly  104  continues pivoting about pivot points  106 ,  108 , the hook  64 , moving downward, eventually reaches the confining limit  65  ( FIG. 5 ) of the confining inside bar  68  and outside bar  70 . When the hook  64  reaches the confining limit  65 , the rear axle assembly  104  stops independently pivoting about pivot points  106 ,  108 .  
         [0029]     With the hook  64  of the plate  62  at its confining limit  65 , the inside bar  68  and outside bar  70  are placed into tension. When placed under tension, two occurrences become evident. The first occurrence is that the frame rail  14  and rear axle assembly  104  begin to bear the load in concert, as opposed to the frame rail  14  alone, since the rear axle assembly  104  is restrained by the hook  64  within the inside bar  68  and outside bar  70 . The second occurrence is that the rear axle assembly  104  is held adjacent the frame rail  14 , proximate its pre-collision position. Because the rear axle assembly  104  is held adjacent the frame rail  14 , the rear axle assembly  104  is held in the line of force  92  and receives a force  102 .  
         [0030]     With the force  102  passing into the spare wheel  96 , which contacts the differential  94  and axle  48 , the force  102  then passes into the upper trailing link  20  as evidenced by force arrow  110  and the lower trailing link  22  as evidenced by the force arrow  112 . Upon the forces  110 ,  112  passing into the links  20 ,  22  they then pass into the frame rail  15 . More specifically, the force passing through the upper trailing link  20  passes into the frame rail  15  as force  114  and then the combined force of force  114  and the lower trailing link force  112  combine as force  116 , which passes into the frame rail  15  in front of the rear axle assembly  104 .  
         [0031]     While  FIGS. 7 and 8  depict a plate  62 , hook  64 , and loop  66  arrangement, the arrangements of other embodiments will accomplish the same task. For example, if the circular cable  12  ( FIG. 1 ) or flat cable  32  ( FIG. 2 ) is utilized in place of the plate  62 , hook  64 , and loop  66  arrangement, when the impact of the load  90  strikes the vehicle  93 , the result is the same. For instance, since the cable  12  and flat cable  32  are attached to the frame  14  and the suspension system, such as the trailing link bracket  16 , the cable  12 ,  32  will extend as far as its length will permit as the axle assembly pivots as a result of the impact, and then the cable  12 ,  32  will reach its limit. When the cable  12 ,  32 , reaches its limit, the rear axle assembly  104  is held adjacent the frame rail  14 , proximate its original, non-impact position to transfer forces into the frame rail  15  in front of the rear axle assembly  104  in accordance with the force transfer described above.  
         [0032]     Like the cable  12 ,  32  and the plate  62 , hook  64 , and loop  66  arrangement, the loop  42  and pin  46  arrangement of  FIGS. 3 and 4  could be used to restrain the rear vehicle suspension, including the rear axle assembly  104  adjacent the rear frame rail  14 . During a rear impact event, when the rear axle assembly  104  moves downward, the pin  46  moves within the loop  42  until the pin  46  meets the limit of its travel within the loop  42 . When this occurs, the rear axle assembly  104  is held adjacent the frame rail  14 , proximate its original, non-impact position to transfer forces into the frame rail  15  in front of the rear axle assembly  104  ( FIGS. 7 and 8 ), in accordance with the force transfer described above.  
         [0033]     An advantage of the above embodiments of the invention is that the frame rail  14  and the rear axle assembly  104  share the load  90  of a rear impact collision, and the rear axle assembly is held under the frame rail  14 , proximate its original position. Additionally, more of the force of the impact is directed into the frame rail  15 , as indicated by the force arrows  102 ,  110 ,  112 ,  114 , and  116 .  
         [0034]     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.