Energy absorbing continuously compliant swept arch for interior trim

Abstract: An energy absorbing trim assembly (16) for covering an inner face of a structural member (28) of a vehicle defining a passenger compartment has an elongated wall portion (18) with a longitudinal axis positionable in a covering relationship over structural member inner face (28). A plurality of swept arch members (20) are arrayed along longitudinal axis (19) in a laterally spaced relationship with respect to structural member inner face (28). Arch members (20) are elastically deformable in response to imposition of a load substantially normal to the structural member inner face (28) and plastically deformable upon contact with structural member inner face (28) to further distribute the load. Energy absorbing pedestal members (22,22') provide for the mounting of energy absorbing trim assembly (16) to a structural member inner face (28). Pedestals (22,22') are plastically deformable in response to imposition of a load substantially normal to a structural member (12). Pedestals (22,22') are provided with mounting clips (30) and locating pins (24) to secure the trim assembly to the structural member (28).

Description: The present invention relates to interior trim components for a vehicle, and more particularly to such interior trim which covers structural members and provides an integrally moulded swept arch structure to absorb impact energy. It is known to provide trim moulding to cover structural members in a vehicle interior. Pillars, headers, roof side rails, and other structural components are commonly covered by injected moulded plastic material to provide an aesthetic appeal to a vehicle interior. It is further know to provide trim pieces which are configured to offer some impact protection to vehicle occupants in the event of a collision. Daniel et al., U.S. Patent No. 5,720,510, which is assigned to the assignee of the present invention, discloses an energy absorbing pillar structure. Daniel teaches a stack of independent crush chambers with the inner-most chamber housing various energy absorbing media. The energy absorbing media includes either C-shaped members, beam-like members, or plastic honeycomb structures. Frost, U.S. Patent No. 5,564,744, discloses an energy absorbing trim component including an energy absorbing longitudinally continuous tube-like or coil-like member between a trim cover and a structural member. Frost further discloses longitudinal or lateral slots cut into the tube-like member to tune the level of kinetic energy absorption. However, due to the shape of the energy absorption member, Frost disadvantageously requires a relatively large volume of space surrounding the structural member to be fully effective. Moreover, Frost fails to take advantage of any energy absorption capability of the trim cover itself. The trim cover is treated as a wholly separate piece and only functions as a aesthetic cover to conceal the actual energy absorption member. Baym, German Patent No. 4,015,375, provides pillar crash protection by locating a multi-segment internal wall defining hollow chambers on a base member between an aesthetic layer and a structural member. Baym essentially teaches crushable chambers overlying vehicle structure. As the chambers are fully operable only when acting in direct relation to the structural member, they disadvantageously fail to provide protection from a large range of impact angles. Nissan, UK Patent Application GB2318551, discloses a deformable trim for a vehicle front pillar and comprising an elongate body with spaced arched ribs and loosely mounted on the pillar, and Honda, Japanese Patent document JP09175297A, discloses a deformable trim according to the preamble of claim 1 with spaced arched ribs and mounting clips at intervals along the trim's length. It is therefore desirable to provide a light weight trim moulding which is elastically and plastically deformable in response to imposition of a load while occupying the minimum amount of space within the vehicle interior. It is further desirable to provide a trim moulding which can be specifically tailored to accommodate a large range of impact angles and structural components. It is still further desirable to provide a trim moulding which is simple to attach to a structural member within a vehicle interior during volume production. Responsive to the deficiencies of the prior art, the present invention provides a light weight interior trim component to cover structural members and provide an integrally moulded swept arch structure which is elastically and plastically deformable in response to imposition of a load. In particular, the present invention provides an energy absorbing trim assembly for covering an inner face of a structural member of a vehicle defining a passenger compartment having an elongated wall portion with a longitudinal axis. The wall portion is positionable in a covering relationship over the structural member inner face. A plurality of swept arch members are arrayed along the longitudinal axis in a laterally spaced relationship with respect to the structural member inner face, the arch members being elastically deformable in response to imposition of a load substantially normal to the structural member and plastically deformable upon contact with the structural member to further distribute the load. The trim assembly is characterised by a plurality of mounting pedestals arrayed along the wall portion longitudinal axis carried in laterally spaced relationship with respect to the structural member inner face. The aforesaid trim assembly is preferably provided with integrally moulded arch members that are defined by an apex area, a long leg, and a short leg whereby the resistance of the arches to deformation is greater proximate to the apex. The aforesaid apex area may be arranged in a facing relationship with respect to the load within the vehicle passenger compartment, the apex area having an enhanced cross-sectional area and the legs extending toward the structural member inner face and tapered in depth from the apex area to the structural member inner face. The pedestals are preferably plastically deformable in response to imposition of a load substantially normal to the structural member. The aforesaid mounting pedestals may be defined by an apex area, a first leg, and a second leg whereby the resistance of the pedestals to deformation is greater proximate to the apex area. The trim assembly may further comprise a mounting clip to secure said trim assembly to said structural member and at least one locating pin having a height greater than the mounting pedestal for locating said trim assembly prior to engagement of said mounting clip. The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a fragmentary perspective view of a passenger compartment of an automotive vehicle showing a trim assembly of the present invention covering a front pillar post; Figure 2 is an enlarged rear perspective view of a portion of the interior trim according to the present invention; Figure 3 is an enlarged sectional view taken along the line 3-3 of Figure 1; Figure 4 is an enlarged sectional view taken along the line 4-4 of Figure 2; Figure 5 is an enlarged sectional view taken along the line 5-5 of Figure 4 showing the energy absorbing trim member installed in a structural member; Figure 6 is an enlarged sectional view taken along the line 6-6 of Figure 4 showing the energy absorbing trim member installed in a structural member; and Figure 7 is an enlarged sectional view taken along line 7-7 of Figure 2. Turning now to the drawings, particularly to Figure 1 thereof, a passenger compartment of an automotive vehicle 10 in which a structural member 12 of the vehicle is shown adjacent to a window 14 and including an energy absorbing trim assembly 16 according to the present invention. The illustrated embodiment displays the trim assembly 16 associated with the A-pillar of the vehicle with it being understood that the present invention is suitable for any pillar, header, roof side rail, or other structural member that is commonly covered by injected moulded plastic material to provide aesthetic appeal to a vehicle interior. In the illustrated embodiment of Figure 2, an enlarged rear perspective view of a portion of the energy absorbing trim assembly 16 according to the present invention is shown. The energy absorbing trim assembly 16 includes an elongated wall portion 18 having a longitudinal axis 19. The wall portion 18 is positionable in a covering relationship over a structural member 12 inner face. A plurality of swept arch members 20 and mounting pedestals 22 are further arrayed along the longitudinal axis 19 in laterally spaced relationship with respect to the structural member 12. The mounting pedestals 22 further includes a locating pin 24 and a clip attachment peg 26 for attaching a mounting clip 30. The mounting clip 30 is operable to secure the trim assembly 16 to a structural member 12. The swept arch members 20 and mounting pedestals 22 can be moulded integral to the elongated wall portion 18 or separately moulded and attached thereto by a suitable adhesive or the like. In the illustrated embodiment of Figure 3, an enlarged sectional view taken along the line 3-3 of Figure 1 displays a swept arch member 20 in relationship to a structural member 12 having an inner face 28. The swept arch members 20 are arrayed along the longitudinal axis 19 in laterally spaced relationship with respect to a structural member 12 to cover an area responsive to imposition of a dynamic load. The unique geometry of the swept arch member 20 efficiently utilises the amount of available space to absorb a dynamic load inflicted substantially normal to a structural member inner face 28. Material selection for the swept arch members 20 includes but is not limited to plastics, aluminium, and mild steel dependent on location, available space, and weight requirements of the specified vehicle. The present invention's applicability to a varied choice of materials provides for the associated control of elastic and plastic deformation characteristics to further tailor the swept arch member's 20 responsiveness to a dynamic load. The various materials may be selectively arrayed along the wall portion 18 to again provide for a desired responsiveness at particular locations along the longitudinal axis 19. The geometry and spacing of the swept arch members 20 can be further varied to specifically accommodate a large range of impact loads, angles and structural components. The geometry of the swept arch members 20 of the present invention may be defined by a polynomial having a degree of two providing a continuously compliant swept arch. The swept arch members 20 being defined by an apex area 30, a long leg 32, and a short leg 34. The arch members 20 provide the unique feature of spanning a specified air gap and furnishing resistance to deformation that is greater proximate to the apex area 30. An enhanced cross sectional-area at the apex area 30 furthers the potential to tailor the responsiveness of the swept arch member 20. In combination with the enhanced apex area 30 the legs may also be tapered in depth and or width from the apex area 30 to each of the leg ends again providing a further opportunity to specifically tailor the arch members 20 to an anticipated dynamic load. The performance characteristics of the energy absorbing trim 16 are best shown by how the swept arches 20 perform under dynamic loading. In operation, a dynamic load is absorbed by the trim assembly 16 in a manner to reduce acceleration through elastic and plastic deformation. The elastic and plastic deformation sequence operates in a controlled manner so as to reduce the magnitude of acceleration and thereby protect the vehicle occupants. Upon imposition of a dynamic load, the first portion of the deformation sequence involves utilising the swept arch 20 geometry to distribute the load across the span of the arch members 20. As the swept arch 20 elastically deforms through the distance between the apex area 30 and the structural member inner face 28 it absorbs kinetic energy. Once the trim assembly has stroked through the distance between the apex area 30 and the structural member inner face 28 the arch members 20 contact the structural member inner face 28. In the final sequence of deformation, the arch members 20 undergo plastic deformation to further absorb the remaining kinetic energy. It may therefore be seen that the energy absorption sequence may be varied by the material and geometry of the swept arch members 20 to specifically tailor the trim assembly 16 to accommodate a large range of impact loads and angles. The mounting of the energy absorbing trim assembly 16 to a structural member inner face 28 is best shown in Figures 4-7. Figure 4 is an enlarged perspective view of a pedestal 22 having an integrally moulded locating pin 24 and clip attachment peg 26. Figure 7 is an enlarged perspective view of a complementary pedestal 22' having only a clip attachment peg 26. Figures 5 and 6 are enlarged sectional views taken along the lines 5-5, and 6-6 of Figure 4 showing the energy absorbing pedestal members 22,22'. The pedestals 22,22' being plastically deformable in response to imposition of a load substantially normal to a structural member 12. The geometry of the pedestals 22,22' are defined by an apex area 40,40', and first and second legs 42,42' whereby the resistance of said pedestals to deformation is greater proximate to said apex area 40,40'. The pedestals 22,22' thereby acting in combination with the swept arch members 20 to further reduce the magnitude of acceleration and thereby aid in protection of the vehicle occupants. The pedestals 22,22' including at least one locating pin 24 and clip attachment peg 26 for directly attaching the trim assembly 16 to a structural member inner face 28. The locating pin 24 having a height greater than the mounting pedestal 22 positions the trim assembly 16 prior to engagement of the mounting clip 30. The locating pin 24, and mounting clip 30 previously attached to the clip attachment peg 26, correspond to holes located in the structural member inner face 28. The trim assembly 16 is thereby simply snapped or clipped in place by inserting the locating pin 24 into a corresponding hole in the structural member inner face 28 to accurately position the trim assembly 16. The mounting clip 30 providing rapid and efficient mounting during volume automobile production.

Claims: An energy absorbing trim assembly (16) for covering an inner face of a structural member (12) of a vehicle defining a passenger compartment, said trim assembly (16) comprising: an elongated wall portion (18) having a longitudinal axis (19), said wall portion (18) being positionable in a covering relationship over said structural member (12) inner face; a plurality of swept arch members (20) arrayed along said longitudinal axis (19) in laterally spaced relationship with respect to said structural member (12) inner face; said arch members (20) being elastically deformable in response to imposition of a load substantially normal to said structural member (12); and upon contact with said structural member (12), said arch members (20) being plastically deformable to further distribute said load; a plurality of mounting pedestals (22,22') arrayed along said wall portion (18) longitudinal axis (19); characterised in that said plurality of mounting pedestals (22,22') is carried in laterally spaced relationship with respect to said structural member (12) inner face. An energy absorbing trim assembly (16) according to claim 1, wherein said arch members (20) are integrally moulded with said elongated wall portion. An energy absorbing trim assembly according to either claim 1 or claim 2, wherein said arch members (20) are defined by an apex area (30), a long leg (32), and a short leg (34) whereby the resistance of said arches (20) to deformation is greater proximate to said apex (30). An energy absorbing trim assembly according to claim 3, wherein said apex area (30) is arranged in facing relationship with respect to said load within said vehicle passenger compartment. An energy absorbing trim assembly according to claim 4, wherein said arch members (20) have an enhanced cross-sectional area in said apex area (30). An energy absorbing trim assembly according to claim 5, wherein said arch members (20) have a deepened area in said apex area (30) and said legs (32,34) extend toward said structural member (12) inner face, said legs (32,34) tapering in depth from said apex (30) to said structural member inner (12) face. An energy absorbing trim assembly according to claim 6, wherein said long leg (32) and said short leg (34) tapering in width from said apex (30) to said structural member (12) inner face. An energy absorbing trim assembly according to any one of the preceding claims, wherein said pedestals (22,22') are plastically deformable in response to imposition of a load substantially normal to said structural member (12). An energy absorbing trim assembly according to claim 8, wherein said mounting pedestals (22,22') are integrally moulded with said elongated wall portion and said mounting pedestals are defined by an apex area, a first leg, and a second leg whereby the resistance of said pedestals to deformation is greater proximate to said apex area. An energy absorbing trim assembly according to either claim 8 or claim 9 in which the mounting pedestals (22) further include a mounting clip (30) to secure said trim assembly to said structural member and a locating pin (24) having a height greater than said mounting pedestal (22) for locating said trim assembly prior to engagement of said mounting clip (30).

Inventors: CALSO STEPHEN MATTHEW, DEB ANINDYA, SAHA NRIPEN KUMAR, CALSO, STEPHEN MATTHEW, DEB, ANINDYA, SAHA, NRIPEN KUMAR
Applicants: FORD GLOBAL TECH LLC, FORD GLOBAL TECHNOLOGIES, LLC
Application year: 1999
Main classification: B60R21
IPC codes: B60R13, B60R21