Abstract:
A front bumper for a mobile vehicle that rotates to provide additional access to the vehicle engine. The rotating front bumper is provided in various embodiments, exemplifying possible modes of configuration and operation thereof. Specifically, methods of retaining the front bumper in a non-rotated position are presented, as are methods for preventing over-extension, and linkages that cause the front bumper to rotate when the hood is opened.

Description:
BACKGROUND OF INVENTION 
   This invention relates to a rotating front bumper that provides easy access to the engine compartment of a mobile commercial vehicle. Specifically, multiple embodiments are disclosed, by means of which the vehicle front bumper, which ordinarily prevents access to the engine compartment, may be rotated forward. In this way, the rearwardly swept ends of the front bumper are moved out of the way. 
   SUMMARY 
   Mobile vehicles, especially heavy and medium-duty commercial vehicles, are commonly configured with the engine located longitudinally forward of the cab and mounted to a set of frame rails, which form the structure of the vehicle. Due to the overall size of these commercial vehicles, access to the engine and associated mechanical systems is provided by means of a forward tilting hood. This is in contrast to a passenger vehicle hood that lifts up from the front and provides access from the top of the engine compartment. This tilting hood allows a technician to service the vehicle engine from a standing position. 
   Additionally, these heavy and medium-duty commercial vehicles are provided with a front bumper, located forward and below the tilting hood. For reasons of aerodynamics, aesthetics, and safety, this front bumper commonly has ends that wrap around the front corners of the vehicle, so that they extend rearwardly before terminating. A front bumper with the characteristic of rearwardly extending termini is known as a “wrap-around” or “swept” front bumper. Occasionally, the front bumper is integrated into the forward tilting hood, but more often it is fixedly mounted to the vehicle frame rails. 
   In the case of previous fixedly attached wrap-around front bumpers, the rearwardly extending termini of the front bumper presented a barrier to a technician attempting to access the engine compartment. This forced the technician to climb over the end of the front bumper, or to squeeze between it and the vehicle front tire. The proximity of the rearwardly extending terminus of the front bumper also prevented rapid egress from a standing position between the vehicle front tire and the engine compartment, a position often occupied by a technician when servicing the vehicle engine. It sometimes even presented a barrier to a technician attempting to access the underside of the engine compartment using a mechanic&#39;s creeper. 
   In the case of previous wrap-around front bumpers that were integrated into the vehicle hood, a major drawback of the integrated design was the fact that, in the event of damage to the front bumper, either the entire vehicle hood would require replacement, or significant work would be involved in detaching the front bumper from the hood assembly. 
   The invention disclosed herein provides a front bumper that is not integrated into the vehicle hood, yet rotates out of the path of access to the vehicle engine. This rotation is accomplished either manually without the use of tools, or by linkage to the vehicle hood. In either case, when the rotating front bumper is in the non-rotated position, it bears against structural members attached to the vehicle frame rails. In this way, the impact and load bearing characteristics of the front bumper are retained. 
   The figures listed illustrate a vehicle with such a rotating front bumper. In the case of a rotating front bumper that is operated manually, several embodiments showing methods by which the front bumper may be restrained are shown. In the case of a rotating front bumper that is operated by means of a linkage, several four-bar type linkages are shown. A four-bar linkage is one wherein two rotating links are coupled by a third link, so that when one link rotates, it imparts motion to the second link through the third link, due to the third link being attached to the first two links at points that are tangent to their rotation. The non-movable member, in this case the vehicle chassis, provides the fourth link. This linkage may be provided in any of a multitude of arrangements, provided that they couple the rotation of the vehicle front bumper to the opening of the vehicle hood, and that the motion that is imparted is favorable to proper clearance between the front bumper and the hood during rotation. 
   In at least one embodiment, a sliding four-bar linkage is used. The advantage of this embodiment is that the hood is allowed to open to a certain extent prior to engaging the rotation of the front bumper. In this way, the hood remains clear of the front bumper during rotation. In another embodiment, the linkage is configured in such a way that an over-the-center type of geometry is used. An over-the-center type of four-bar linkage is one in which the distal end of one of the rotating links crosses a centerline drawn between their fixed ends. The advantage of using this type of geometry is that, upon application of a rotating force upon the front bumper, the linkage compels the hood further towards the closed position. This configuration gives greater security against the front bumper and hood articulating inadvertently, due to the fact that the force bears upon the hood seat, rather than upon the hood restraints. 
   The invention as presented is a solution to one of the maintenance difficulties heretofore inherent in the design of heavy-duty commercial vehicles with wrap-around front bumpers. It allows access to the vehicle engine without requiring a technician to climb over the rearwardly extending terminus of the front bumper, while retaining the aerodynamic, aesthetic, and safety advantages of the wrap-around front bumper design. Additionally, it allows the use of a non-integrated front bumper, so that in the event of damage to the front bumper, removal and replacement of the front bumper remains a simple procedure. 

   
     DRAWINGS 
     FIG.  1 —A front view of a vehicle upon which the invention may be used. 
     FIG.  2 —A front view of a vehicle made in accordance with a first embodiment of the invention. 
     FIG.  3 —A front view of a vehicle made in accordance with a second embodiment of the invention. 
     FIG.  4 —A front view of a vehicle made in accordance with a third embodiment of the invention. 
     FIG.  5 —A front view of a vehicle made in accordance with a fourth embodiment of the invention. 
     FIG.  6 —A front view of a vehicle made in accordance with a fifth embodiment of the invention. 
     FIG.  7 —A front view of a vehicle made in accordance with a sixth embodiment of the invention. 
     FIG.  8 —A side view of a vehicle made in accordance with a seventh embodiment of the invention. 
     FIG.  9 —A side view of a vehicle made in accordance with a eighth embodiment of the invention. 
   

   DETAILED DESCRIPTION 
   The vehicle  101  shown in  FIG. 1  has a cab  102  and a hood  103  engaged to a chassis  104 . The vehicle  101  also has a front bumper  105  attached to the chassis  104 . The chassis  104  is provided with front wheel and tire assemblies  126 . Furthermore, the front bumper  105  is provided with rearwardly extending termini  127 , which are proximate to the front wheel and tire assemblies  126 . This is an example of the type vehicle to which this invention may be applied. 
   The vehicle  101  shown in  FIG. 2  has a similar cab  102  and hood  103  attached to a chassis  104  as the vehicle  101  shown in  FIG. 1 . The hood  103  is shown in an open position, thereby providing access to an engine  123  installed on the chassis  104 . The front bumper  105  is attached to the chassis  104  by means of the front bumper mounting brackets  106 , and is shown rotated about pivot pins  107  engaged through passages in the mounting brackets  106 . Rotation of front bumper  105  has caused rearwardly extending bumper termini  127  to increase in distance from front wheel and tire assemblies  126 , increasing access therebetween. Restraining straps  108  engaged between the front bumper  105  and the chassis  104  prevent the front bumper  105  from over-extending and contacting the ground. The restraining straps  108  are loose until the front bumper  105  starts to unfold and become taut at the point of desired maximum rotation of the front bumper  105 . 
   The vehicle  101  shown in  FIG. 3  has a similar cab  102  and hood  103  attached to a chassis  104  as the vehicle  101  shown in  FIG. 2 . The hood  103  is shown in a closed position, and is partially removed to show additional detail. The front bumper  105  is shown in a non-rotated position, and is provided with front bumper latching brackets  109  having bumper latching bracket holes  125 . The chassis  104  is provided with compatible frame latching brackets  110  having frame latching bracket holes  124 . In  FIG. 3 , one front bumper latching bracket  109  is shown partially removed, in order to show additional detail of frame latching bracket  110  and frame latching bracket hole  124 . By aligning bumper latching bracket holes  125  and frame latching bracket holes  124 , and inserting latching pins  111  and attaching devises  112 , the front bumper  105  may be securely retained in the non-rotated position as shown. 
   The vehicle  101  shown in  FIG. 4  has a similar cab  102  and hood  103  attached to a chassis  104  as the vehicle  101  shown in  FIG. 2 . The hood  103  is shown in a closed position, and is partially removed to show additional detail. The chassis  104  is provided with elastic front bumper latch devices  113 . The front bumper  105  is shown in a non-rotated position, and is provided with elastic front bumper latching receivers  114 . By engaging the elastic front bumper latching devices  113  to the elastic front bumper latch receivers  114 , the front bumper  105  may be securely retained in the non-rotated position as shown. 
   The vehicle  101  shown in  FIG. 5  has a similar cab  102  and hood  103  attached to a chassis  104  as the vehicle  101  shown in  FIG. 1 . The front bumper  105  is attached to the chassis  104  by means of the front bumper mounting brackets  106 , and may rotate about pivot pins  107  engaged through passages in the mounting brackets  106 . Both the hood  103  and the front bumper  105  are shown with sections partially removed to show additional detail. Rotation of front bumper  105  is accomplished by means of a sliding four-bar type of linkage, comprised of the front bumper link  115 , the sliding vertical link  116 , and the hood link bracket  118 . The front bumper link  115  is affixed to the front bumper  105 , and the hood link bracket  118  is affixed to the hood  103 . When the hood  103  is in the closed position as in  FIG. 5 , the front bumper link  115  is engaged to the sliding vertical link  116  at the end of sliding vertical link slot  117  most proximate to the hood link bracket  118 . Because the hood  103  is retained in the closed position, the front bumper  105  may not freely rotate about pivot pins  107 , and is securely retained in the non-rotated position. When the hood  103  is raised, the point of engagement of the front bumper link  115  to the sliding vertical link  116  moves to the end of the sliding vertical link slot  117  most distal from the hood link bracket  118 . As the hood  103  continues to raise beyond the point where the front bumper link  115  point of engagement has reached the end of the sliding vertical link slot  117  most distal from the hood link bracket  118 , sliding vertical link  116  compels front bumper link  115 , and therefore front bumper  105 , to rotate. In this way, clearance is maintained between the hood  103  and the front bumper  105  during articulation. In  FIG. 5 , the hood  103  is shown in a closed position and the front bumper  105  is shown in a non-rotated position, with the front bumper link  115  engaged to the sliding vertical link slot  117  at its end most proximate to the hood link bracket  118 . 
   The vehicle  101  shown in  FIG. 6  has a similar cab  102  and hood  103  attached to a chassis  104  as the vehicle  101  shown in  FIG. 5 . The front bumper  105  is again attached to the chassis  104  by means of the front bumper mounting brackets  106 , and may rotate about the pivot pins  107  engaged through passages in the mounting brackets  106 . Both the hood  103  and the front bumper  105  are shown with sections partially removed to show additional detail. Rotation of the front bumper  105  is again accomplished by means of a sliding four-bar type of linkage, comprised of the front bumper link  115 , the sliding vertical link  116 , and the hood link bracket  118 . The front bumper link  115  is affixed to the front bumper  105 , and the hood link bracket  118  is affixed to the hood  103 . In  FIG. 6 , the hood  103  is shown in a partially open position, partially revealing an engine  123  installed on the chassis  104 . The front bumper  105  is shown in a non-rotated position, and the front bumper link  115  is engaged to the sliding vertical link slot  117  at its end most distal from the hood link bracket  118 . Further opening of hood  103  will compel front bumper link  115 , and therefore front bumper  105 , to rotate. 
   The vehicle  101  shown in  FIG. 7  has a similar cab  102  and hood  103  attached to a chassis  104  as the vehicle  101  shown in  FIG. 5 . The front bumper  105  is again attached to the chassis  104  by means of the front bumper mounting brackets  106 , and may rotate about pivot pins  107  engaged through passages in the mounting brackets  106 . Both the hood  103  and the front bumper  105  are shown with sections partially removed to show additional detail. Rotation of the front bumper  105  is again accomplished by means of a sliding four-bar type of linkage, comprised of the front bumper link  115 , the sliding vertical link  116 , and the hood link bracket  118 . The front bumper link  115  is affixed to the front bumper  105 , and the hood link bracket  118  is affixed to the hood  103 . In  FIG. 7 , the hood  103  is shown in a fully open position, thereby providing access to an engine  123  installed on the chassis  104 . The front bumper  105  is shown in a rotated position, with the front bumper link  115  engaged to the sliding vertical link slot  117  at its end most distal from the hood link bracket  118 . Rotation of front bumper  105  has caused rearwardly extending bumper termini  127  to increase in distance from front wheel and tire assemblies  126 , increasing access therebetween. Restraining straps  108  engaged between the front bumper  105  and the chassis  104  prevent front bumper  105  from over-extending and contacting the ground. Prior to and during articulation, these restraining straps  108  are loose, and become taut at the point of desired maximum rotation of the front bumper  105 . 
   The vehicle  101  shown in  FIG. 8  has a similar cab  102  and hood  103  attached to a chassis  104  as the vehicle  101  shown in  FIG. 1 . The hood  103  is shown in an open position, and the front bumper  105  is shown in a rotated position, thereby providing access to an engine  123  installed on the chassis  104 . Rotation of front bumper  105  has caused rearwardly extending bumper termini  127  to increase in distance from front wheel and tire assemblies  126 , increasing access therebetween. Both the hood  103  and the front bumper  105  are shown with sections partially removed to show additional detail. Rotation of the front bumper  105  is accomplished by means of an over-the-center type of four-bar linkage, comprised of the hood link  119 , the vertical link  120 , and the front bumper link  121 . The hood link  119 , the vertical link  120 , and the front bumper link  121  are all shown in simplified form, in order to facilitate visualization of the linkage motion. The hood link  119  is affixed to and constrained to rotate with the hood  103 , and the front bumper link  121  is affixed to and constrained to rotate with the front bumper  105 . 
   The vehicle  101  shown in  FIG. 9  has a similar cab  102  and hood  103  attached to a chassis  104  as the vehicle  101  shown in  FIG. 8 . The hood  103  is shown in a closed position, and the front bumper  105  is shown in a non-rotated position. Both the hood  103  and the front bumper  105  are shown with sections partially removed to show additional detail. Rotation of the front bumper  105  is again accomplished by means of an over-the-center type of four-bar linkage, comprised of the hood link  119 , the vertical link  120 , and the front bumper link  121 . The hood link  119 , the vertical link  120 , and the front bumper link  121  are all shown in simplified form, in order to facilitate visualization of the linkage motion. The hood link  119  is affixed to and constrained to rotate with the hood  103 , and the front bumper link  121  is affixed to and constrained to rotate with the front bumper  105 . Upon closure of the hood  103 , the hood link  119  rotates sufficiently that its end most distal from the front bumper  105  passes over the centerline  122 , with the result that, when the hood  103  is in the closed position and the front bumper  105  is in the non-rotated position as shown, the application of a rotating force upon the front bumper  105  compels the hood  103  further into the closed position. As a result, only an intentional opening of the hood  103  will result in the rotation of the front bumper  105 . A rotating force upon the front bumper  105  will not result in the inadvertent opening of the hood  103 . 
   Other permutations of the invention are possible without departing from the teachings disclosed herein, provided that the function of rotating the front bumper  105  is to allow access to an engine  123 . Other advantages to a vehicle  101  equipped with a rotating front bumper  105  may also be inherent in the invention, without having been described above.