HK1100748A - Bumper for reducing pedestrian injury - Google Patents

Description

Bumper capable of reducing pedestrian injury

The present patent application is a divisional application of the invention patent application No. 03817620.3.

Technical Field

The present invention relates to bumpers for passenger vehicles for reducing pedestrian injury in an impact, and more particularly to bumpers having energy reducers which are leveraged to provide a softer initial impact and a "throwing" force from the bumper after an impacted pedestrian is initially impacted.

Background

In the united states, automatic bumper systems have been designed to resist damage from low and high vehicle speeds and for high energy absorption in high crash speed situations. In recent years, pedestrian safety has begun to receive increasing attention. However, bumpers designed for pedestrian safety are complicated by the many conflicting functional requirements. The obvious problem is that the human body cannot withstand high energy impacts, and also cannot withstand rapid impacts that do not substantially harm muscle and bone tissue. However, it is difficult to reduce the magnitude and rate of energy transfer from the bumper to the pedestrian upon impact, and in particular, to reduce the energy transfer immediately due to a "crash" impact, because automotive bumpers are generally limited to being impacted relatively softly by some components behind the bumper, such as the radiator and other engine components, and to being impacted by other front end components and support structures. This is especially true in smaller and more compact vehicles. In addition, the bumper must be made of a strong material to maintain its shape and appearance over time and to provide its primary function as an automobile "bumper", i.e., to push away items and prevent damage to the automobile. The problem is compounded by aerodynamic design considerations, in which case the corners of the bumper system are swept back into the vehicle fender, which in turn further limits the travel of the bumper and the ability of the bumper to collapse or flex. Also, the problem is compounded by the fact that pedestrian related car accidents often involve trauma to the pedestrian's knees due to the even knee height of the bumper. Joints and exposed bones are particularly vulnerable to injury during a collision.

Accordingly, there is a need for a bumper system that addresses the above-mentioned problems and provides the above-mentioned advantages.

Disclosure of Invention

In one aspect of the invention, a bumper system for an automobile includes a beam adapted for attachment to the automobile and an energy absorber engaged with a surface of the beam. The energy reducer has the following parts: a top horizontal portion defined by a top wall and an upper middle section wall to which the upper front wall is connected; a bottom horizontal portion defined by a bottom wall to which the lower front wall is connected and the lower middle section wall; and a middle horizontal portion defined by an upper middle section wall and a lower middle section wall connected by a middle front wall. The top and bottom horizontal portions include top and bottom front end portions (front nose sections) extending forwardly of the central front wall and defining a horizontal passage therebetween forwardly of the central front wall. The front nose portions are configured to provide a first level of energy absorption during an initial impact stroke that collapses one or both of the front nose portions, while the top, middle and bottom horizontal portions provide a higher second level of energy absorption during a continuing impact stroke that collapses the energy reducer against the beam surface. Fascia trim (fascia) covers the energy absorber and the beam. With this arrangement, during an initial frontal impact stroke, the front portions of the top and bottom portions are formed with lower energy absorption to "catch" an impacted object, such as a person's knee, and during the next further continued impact stroke, the top, middle and bottom horizontal portions are squeezed (crush) to form increased energy absorption.

Viewed from another aspect the invention comprises a bumper system for an automobile comprising a beam adapted to be attached to the automobile and having a longitudinal curvature (curvature) shaped to match the aerodynamic curve shape of the front of the automobile when viewed from above where it is mounted on the automobile. The bumper system also includes an energy absorber engaged with a surface of the beam. The energy reducer has a top horizontal portion defined by a top wall to which the upper front wall is connected and an upper middle section wall; there is also a bottom horizontal portion defined by the bottom wall and the lower middle section wall connected by the lower front wall such that the top and bottom horizontal portions include forwardly extending top and bottom front end portions. Each of the front end portions of the top and bottom sections are semi-rigid, but are collapsible in a parallelogram motion that vertically displaces one or both of the top front wall and the bottom front wall, such that a horizontal impact force is at least partially converted to a vertical force upon receiving a horizontal frontal impact during an initial stroke of the frontal impact. With this arrangement, during a first partial frontal impact, the front end portions of the top and bottom portions are formed with lower energy absorption to "catch" an impacted object, such as a person's knee, and during the next further sustained impact stroke, the horizontal portions of the top, middle and bottom portions are squeezed to form increased energy absorption.

In accordance with yet another aspect of the present invention, a bumper system for an automobile includes a cross member adapted to be attached to the automobile and having a curved longitudinal shape when viewed from above its location on the automobile, the cross member including mounts (mounts) at ends of the cross member. The energy reducer engages the beam surface. The energy absorber has a central portion that engages the surface of the beam and has end portions that extend outwardly from the central portion and at least partially surround the associated ends of the beam. Each of the end portions has an enlarged free end portion and a transition portion connecting the free end portion with an end of the central portion. Each transition portion of the energy reducer tip portion is configured to be less energy absorbing during a first portion of the bumper stroke caused by a corner impact and is configured to be torsionally compressed, such that the enlarged free end portion swings back and "catches" an impacted object, such as a person's knee, and during a subsequent further portion of the bumper stroke, the transition portion provides increased energy absorption and reaction force, such that the free end portion pushes away the impacted object due to the non-parallel resistive forces generated in the energy reducer with the line of impact (a) and due to the impacted object sliding along the slope of the free end portion.

Viewed from a further aspect, a method comprises the steps of constructing a bumper system comprising a stiff beam and an energy absorber on a surface of the beam. The energy reducer has a top portion, a middle portion, and a bottom portion, the top portion and the bottom portion defining a front end portion extending forwardly from the middle portion. The front end portions define a space therebetween forward of the central portion, and the top and bottom front end portions are configured to deflect in a parallelogram motion upon impact and to move at least one of the front end portions vertically in a parallelogram motion in response to an impact directed horizontally toward the front of the bumper system such that energy directed at the knees of the impacted person is converted to a throwing force directed toward the person along a line substantially perpendicular to the line of impact and away from the vehicle bumper system.

The object of the present invention includes providing a bumper system adapted to initially "catch" a person during the initial phase of a collision, which transfers less energy and force to the person and/or transfers force at a slower rate during the initial phase and thus is likely to cause less injury. The object of the invention also consists in redirecting the impact forces transmitted to the person from a line parallel to the direction of impact to an upward or downward direction (in the case of a frontal impact) or to a lateral direction (in the case of a corner impact). Through these activities, the impacted person is initially "caught" and then "thrown" in a direction away from the impact line, thereby reducing injury and reducing damage to the vehicle bumper system.

These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.

Drawings

FIG. 1 is a side elevational view of a bumper system on an automobile embodying the present invention;

FIG. 2 is a perspective view of the bumper system shown in FIG. 1;

FIGS. 3-5 are enlarged views showing the bumper system of FIG. 1, wherein FIG. 3 shows the bumper system when it has not yet impacted frontal-ly against a person's knees and legs, FIG. 4 shows the bumper system during an initial partial frontal impact against the knees and legs, and FIG. 5 shows the bumper system during a continued partial frontal impact;

FIG. 6 is a plan view of the bumper system shown in FIG. 1, with phantom lines (phantom lines) included to show the initial collapse/deflection of the front portion of the energy reducer, dashed lines showing the secondary crushing of the energy reducer, and dashed lines showing the deformation and straightening of the energy reducer, and FIG. 6 also showing dotted lines depicting the result of using the present energy reducer with a highly hardened beam that neither collapses nor substantially deforms;

FIG. 7 is a force-deflection curve (force-deflection curve) illustrating the condition of the energy reducer in the event of a collision with the bumper system shown in FIG. 1;

fig. 8-10 are schematic plan views showing a sequence of corner impacts, where fig. 8 shows the corners of the bumper system immediately prior to the corners being impacted, fig. 9 shows the corners during an initial portion of a corner impact, and fig. 10 shows the corners during a continuing portion of a corner impact.

Detailed Description

The vehicle bumper system 20 (see fig. 1-2) includes a beam 21 and an energy absorber 22 with top and bottom horizontal portions 23, 24 and a middle horizontal portion 25. The top and bottom horizontal portions 23, 24 form top and bottom front portions 26 and 27 which are semi-rigid but collapse in a parallelogram motion that moves the top and bottom portions 26 and 27 vertically up (or down) during a collision. As a result, during the initial stroke of the front impact (see fig. 4), the horizontal impact force 30 is partially converted into a vertical force 31, which acts to "catch" the knees 29' (see fig. 4) of a person 29 during the impact. During the continued collision stroke (see fig. 5), the top and bottom horizontal portions 23, 24 produce a "throwing" action, shown in the figures as increasing forces 31 and 31'. During the continued collision stroke, the horizontal portions 23 to 25 are also compressed and form an increased energy absorption, as shown in fig. 5. These forces 31 and 31' combine to "throw" the impacted person 29 upward in a direction away from the bumper beam 21. Since most of the person's weight is above the person's knee, most of the force 31 is upward. It is noted, however, that as shown in FIG. 5, there is also a component of the downward vertical force 31'.

The length of the energy absorbing stroke (see fig. 6) of bumper system 20 is extended by the use of a beam 21 having a shallow cross-section that occupies less space due to the small depth. Specifically, the beam 21 has a height to depth ratio of at least 3: 1, and preferably a ratio of 4: 1 or greater, such that the beam 21 flexes and deforms more easily than many existing bumper beams. The shallow cross member reduces the amount of space occupied by the cross member 21 in front of the radiator and also reduces the coupling of the energy absorber 22 to the dynamic factors of energy absorption (the dynamics) during an impact, and the compression flexes the cross member 21 to "catch" a person in a hammock-like action, thereby reducing injury to the person during the impact. Additionally, with the increased stroke, energy absorption is not reduced to an unacceptable level for many automobiles. It is noted that although the cross beam 21 may be bent in a "hammock-like action", the cross beam 21 is so strong that it will flex and deform and generate forces only upon a substantial impact. Additionally, these functional features may differ due to aspects of the design of bumper system 20, as discussed below.

The energy reducer 22 also has an end portion 34 (see fig. 8) extending near the end of the beam 21 that forms a collapsible corner that initially absorbs energy generated by the impact force 30 at a relatively low rate during an impact, thereby substantially "catching" the person impacted. During the initial impact stroke (see fig. 9), the end portion 34 causes the rear portion 38 of the energy reducer 22 to slidingly engage the side of the fitting 39 as a result of absorbing energy along the line 37, i.e., torsionally collapsing in the direction 36. During the continuing collision stroke (see fig. 10), the energy reducer 22 generates an increasing transverse force to "catch" the impacted person in a direction 39' laterally away from the vehicle during the continuing collision stroke.

The illustrated beam 21 (see fig. 3) is a rolled channel and includes a transverse cross-section defining a front-to-back serpentine shape. Other channels are contemplated, such as molded channel material, and different cross-sectional shapes may be used without departing from the scope of the present invention. Here the cross section comprises: a central wall 40 opposite lateral flanges 41, 42 extending forwardly from each edge and defining a channel 43; top and bottom walls 44, 45 extending upwardly and downwardly from flanges 41, 42, respectively; and top and bottom edge flanges 46, 47 extending rearwardly from the top and bottom walls 44, 45, respectively. The front surface of the cross-member 21 defines a shape adapted to matingly engage the rear surface of the energy reducer 22 with the channel 43 engaging a ridge 63 on the energy reducer 22 to form an "anchor" that prevents the energy reducer 22 from sliding up the cross-member 21 (or down the energy reducer 22) during a frontal impact. Apertures or detents 48 are formed in the top and bottom edge flanges 46, 47 for receiving protruding hooks 49 on the energy damper 22 to temporarily hold the energy damper 22 on the cross member 21 during assembly. During assembly, the fascia trim 50 is positioned over the bumper system 20 prior to or during assembly of the bumper system 20 to the vehicle.

The top horizontal portion 23 (see fig. 3) of the energy reducer 22 includes a top wall 52 and an upper mid-section wall 53 connected by an upper front wall 54. The bottom horizontal portion 24 includes a bottom wall 55 and a lower mid-section wall 56 connected by a lower front wall 57. The middle horizontal portion 25 includes a middle front wall 58 that connects the upper middle wall 53 with the lower middle wall 56. The central front wall 58 is recessed rearwardly from the front walls 54 and 57 by about 1 inch and one-half or 2 inches so that the top and bottom front end portions 26 and 27 project forwardly from the central front wall 58. In addition, the front wall halves 54 and 57 closest to wall 58 are arranged angled inwardly to form an enlarged "mouth" or inlet to channel 58', as described below. In addition, a rectangular aperture is formed in the middle front wall 58. A vertical/front/rear reinforcing wall 59 extends transversely between the walls 52, 53, 55, 56 at the edge of the aperture and forms a box-like portion to allow the walls 52, 53, 55, 56 to function to stabilize the walls relative to each other. The walls 52-59 may be continuous to form a solid honeycomb grid, or may be discontinuous, and/or include apertures. By these changes, different impact strengths and energy absorption characteristics can be achieved with the energy reducer 22. Also, the material composition and wall thickness may be varied to create different energy absorption characteristics.

The walls 52, 53, 55, 56 extend substantially in a horizontal plane and parallel to the vehicle when the energy reducer 22 is in a position for installation on the vehicle. The walls 52, 53, 55, 56 are shown as extending in the fore/aft direction and are corrugated or corrugated to accommodate increased impact strength, although it is contemplated that other shaped walls may be used. The front walls 54 and 57 extend generally vertically, except where they include an angled portion that enters the channel 58', and they are coplanar and parallel, and are curved when viewed from above, the curvature matching the shape of the dynamic front of the vehicle. The central front wall 58 extends generally parallel to the front walls 54 and 57, but is spaced rearwardly about 1 and one-half inches or 2 inches. By this arrangement it connects the top nose portion 26 with the bottom nose portion 27 to stabilize the nose portions 26 and 27, but so that the nose portions 26 and 27 can flex independently in a parallelogram motion (compare fig. 3-5). The central front wall 58 is shown with a rectangular aperture 60 formed therein, which is intermittently positioned along the central front wall 58. The apertures 60 are bounded by walls 53 and 55 at their top and bottom and by vertical walls 59 on their side edges, so that the walls 53, 55 and 59 form a box-like portion around each aperture 60. A rear wall 61 is formed along the rear of the energy reducer 22. Rear wall 61 and the rear half-inch of walls 53, 54, 55, 56 together form a ridge 63 matingly engageable with channel 43 on beam 22. The back wall 61 is aligned with each of the openings 60 so that the mold for making the energy reducer 22 can be made without the need for drawing (pulls) and cams and without moving the mold parts used to make the closure surfaces.

The top and bottom front end portions 26 and 27 extend forward of the central front wall 57 and define a horizontal channel 58' therebetween forward of the central front wall 57. The forward front end portions 26 and 27 are configured to provide a first level of energy absorption during an initial impact stroke that collapses one or both of the forward front end portions 26 and 27 in a parallelogram-like motion (compare fig. 3-4). It is clear that the parallelogram-like motion results in some kind of energy absorption due to the crumpling effect of the parallelogram motion on the reinforcing walls 59 and also due to the bending forces absorbed by the walls 53, 54, 56 and 57. However, the parallelogram action of the force concentration points (focus) on the nose portions 26 and 27 combined with the column strength (column strength) of the walls 53, 54, 56, 57 results in a large percentage of the horizontal force of the initial impact being converted into vertical force 31. Initially, the pedestrian's knees 29 ' enter the channel 58 ' and strike the front end portions 26 and 27, vertically offsetting the two portions (see FIG. 4). As the crash stroke continues (see fig. 5), the top, middle and bottom horizontal portions 23-25 provide a higher second level of energy absorption as the energy reducer 22 collapses against the surface of the cross member 22.

Fig. 6-7 illustrate a second manner in which the present bumper system reduces pedestrian injury. In the present bumper system (see FIG. 6), the impacts produce successive offset distances 70, 71, 72, and 73. Upon impact, the front end portions 26 and 27 of the energy absorber 22 initially bend in a parallelogram type motion, which causes the front surface of the bumper system to shift a rearward distance 70. As the impact continues, the energy reducer 22 is pressed a further distance 71 against the surface of the beam 21. As the collision continues, the cross member 21 is deformed a further distance 72 between it and the car mount 39 towards a straightened condition. The last distance 73 represents an offset distance when the fitting 39 is telescopically squeezed/collapsed and when the bumper beam 21 and the energy absorber 22 are driven toward the radiator 75. In the graph of fig. 7, the distances 70 to 73 are represented by line segments 76 to 79, and the energy absorption is represented by the area under the curve formed by the line segments 76 to 79. It is to be noted that the energy reducer 22 can be used on a tubular rigid cross-beam 21 ' that tends not to bend, but in this case the bumper system may occupy a spatial range (dimension)74, and may also collapse only a sum of distances 70, 71 and 73 ' (since the cross-beam 21 ' does not bend to be straight).

As described above, the energy absorber 22 is adapted to cope with a corner collision by being combined with the end portion 34 (see fig. 8) extending near the end of the bumper beam 21. The end portion 34 forms a collapsible corner that initially absorbs energy generated by the force 35 of a corner impact at a relatively low rate during the impact so that it substantially "catches" the impacted person's knee. During an initial collision stroke (see fig. 9), the tip portion 34, upon absorbing energy along line 37, also torsionally collapses in direction 36, causing the rear portion 38 of the energy reducer 22 to slidingly engage the sides of the fitting 39. During the sustained impact stroke (see fig. 10), the energy reducer 22 generates an increased lateral force in the direction 39' that "throws" the person sideways away from the vehicle during the sustained impact stroke.

More specifically, the distal portion 34 of the energy reducer 22 includes an enlarged free end portion 75 and a transition portion 76 that connects the free end portion 75 with a central portion 77 of the energy reducer 22. The transition portion 76 includes a trapezoidal shaped rearwardly extending portion 78 which extends rearwardly to a position adjacent the outside of the fitting 39. The honeycomb box portion 79 is positioned outside the trapezoidal shaped portion 78, and includes a first side connected to the trapezoidal shaped portion 78, and a second side connected to the free end 75.

In the initial phase of a collision, the collision force from the collider 80 is guided along a line of force (a line of force), such as line of force 35, into the tip portion 34. Forces are transmitted along lines 37 and 82 through honeycomb box section 79 and along line 83 in trapezoidal shaped section 78. The trapezoidal shaped portion 78 engages the side of the fitting 39 and slides back along the fitting 39 in the direction 83 as the compression progresses. During a further part of the initial phase of the collision (see fig. 8), the trapezoidal shaped portion 78 and the honeycomb box portion 79 are pressurized in such a way that the free end 75 is turned backwards along the line 36. As this occurs, the honeycomb box-like portions 79 are pressurized in the direction 82. Also, when the end portion 34 resists a corner impact, the force associated with the impactor 80 begins to diminish in the direction of the impact (see short arrow 35 ') and the force is redirected along the line 39'. As the impact continues (see fig. 10), the free end 75 bends further in the direction 36. However, the honeycomb box-like portions 79 rebound in the direction 39', increasing redirection force 39 "and further reducing the force 35" of the impactor 80 against the end portion 34. As a result, the colliding body 80 is "thrown" away from the vehicle by the increased redirecting forces 39' and 39 ".

In summary, each transition portion 76 initially provides a lower energy absorption and is further torsionally compressed such that the enlarged free end portion 75 swings rearwardly and "catches" an impacted object, such as a person. The transition portion 76 then reacts during a further part of the bumper stroke, so that the transition portion 76 produces an increased energy absorption and a reaction force, so that the free end pushes away the impacted object as a result of the transverse resistance produced by the energy reducer being non-parallel to the impact path and as a result of the impacted object sliding along the slope of the free end.

It is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.

Claims (1)

1. A method of reducing pedestrian injury comprising the steps of:

constructing a bumper system including a stiff beam and an energy absorber on a surface of the beam, the energy absorber having top, middle and bottom portions defining front end portions extending forwardly from the middle portion, the front end portions defining a space therebetween forward of the middle portion, the front end portions of the top and bottom portions being configured to deflect in a parallelogram motion in the event of a collision; and

at least one of the front end portions is moved vertically in a parallelogram motion in response to an impact directed horizontally toward the front of the bumper system, whereby energy directed at the knees of the impacted person is converted into a throwing force directed toward the person substantially perpendicular to the line of impact and away from the bumper system of the vehicle.