Foam-in place inflatable restraint

Abstract: A method for integrally molding a pre-­ assembled door within an instrument panel to provide a cover for a safety air cushion device comprises the steps of molding the plastic instrument panel about and over the door in situ of a mold cavity and thereafter the step of removing a portion of the instrument panel which overlies the door to provide an opening therein to expose the door for opening movement with respect to the instrument panel upon deployment of the air cushion device. The invention further includes the resultant structure of a integrally molded door and instrument panel assembly having an opening formed in the instrument panel assembly for both defining a ledge to support the door and to define a path for impacting a air cushion device against the door to cause the door to be lifted from its integrally mold seated relationship on the ledge for further deployment of the air cushion device into the passenger compartment of a vehicle.

Description: Field of the Invention This invention relates to covers for safety air cushion devices and more particularly to a method for forming a molded in place door within an instrument panel which is openable to provide for deployment of an air cushion and to a resultant door and instrument panel assembly made by such process. Description of the Prior Art Various methods have been proposed to form an integral cover over a deployable air cushion restraint located within the confines of an automotive interior part such as an instrument panel. One such method is set-forth in USPN 4,246, 213 in which the cover member includes an outer skin of polyvinyl-chloride resin material backed by a layer of foamed polyurethane material. The method includes the step of pre-slitting or cutting the cover member to provide a weakened section therein which will rupture to provide an escape path in the cover member when the air cushion restraint is deployed into the passenger compartment. USPN 3,622,176 discloses a cover for an air cushion restraint system located in the forward passenger compartment in which the outer cover is weakened such that the air cushion will rupture the cover to provide a release path during its deployment. USPN 3,887,214 discloses a cover for an air cushion assembly in which overlapping molded segments swing outwardly to define a path for release of the air cushion into the passenger compartment. The overlapped molded segments are joined by a heat sealed joint which is ruptured to enable the molded segments to swing apart. Alternatively, a mechanical interconnect in the form of a ball socket strip can be formed to join the overlapping segments. In either case a deployment force is required to separate the cover before an opening is formed for deployment of the air cushion device. USPN 3,801,126 discloses an instrument panel in which an air cushion device is stored behind a cover or door which fits within an instrument panel opening. The instrument panel and the cover are separately fabricated and are assembled following molding of the component parts of the instrument panel. Furthermore, the cover has marginal covering flanges that must be separately joined to clip members of a separate manifold housing that contains an air bag of a particular form which applies a force on the door causing its rear and side marginal edges to tear free of the manifold clip members such that the door will swing inwardly of the passenger compartment as the air bag deploys. In each of the aforesaid cases, the cover is either ruptured or a portion of the cover requires a separation force at a member portion thereof to either cause the production of an undesirable dispersion of particles into the passenger compartment during air cushion deployment or increase the rupture force required for deployment of the air cushion through its cover. Summary of the Invention The present invention provides a method in which a cover or door for an air cushion restraint system is molded in situ of an interior trim component of a vehicle such as an instrument panel so as to improve the form and fit appearance of the interior of a passenger vehicle in which the air cushion restraint is located for deployment on vehicle impact. A feature of the present invention is that a door component is molded in situ with an interior trim component of a vehicle to eliminate form and fit differences in separately formed and assembled parts thereby to improve the exterior appearance of the resultant product. A further feature of the present invention is to provide a method for such in situ molding wherein the door has an interior trim panel molded above and around the door followed by removing a portion of the interior trim panel to provide an access opening to the door through which an air cushion can be deployed to protect vehicle passengers upon vehicle impact. Still another feature of the present invention is to provide a method including such in situ molding and wherein the door component is initially placed in a mold cavity and thereafter covered with an outer skin of the interior trim panel after which the interior trim panel is foamed with a layer of polyurethane material to encapsulate the inboard face and sides of the door while leaving the outboard face thereof exposed and form fit with the surrounding outer skin of the interior trim panel and wherein the method includes the steps of removing a non-observable segment of the foam layer to expose the back or inboard surface of the door to an air cushion device covered by the interior trim panel and the door molded in situ therewith. Another feature of this invention is to provide a cover for an air cushion device deployable into a passenger compartment to protect vehicle passengers upon vehicle impact wherein the cover includes a formed in situ door of a material which differs from the properties of a surrounding foamed-in-place interior trim panel while having a close tolerance form and fit relationship therewith and wherein the door is retained in the interior trim panel by die lock segments of the panel to mask any edge imperfections either in form or fit within the door component. Still another feature of this invention is to provide a combination door and interior trim panel molded together to form a common perimeter defining the area through which an air cushion device is deployable upon vehicle impact and wherein the door is separable from the panel as a unit by impact through a rear access opening in the panel which is smaller than the door. The above and other beneficial features, objects and advantages of the invention are attained in accordance with the present invention by a method which includes preforming a door for covering an air cushion device deployable into a passenger compartment upon vehicle impact wherein the door is molded in situ in a urethane foamed panel in the form of an instrument panel. The preformed door is first placed in a pocket of a vinyl skin of the instrument panel and the skin and door are placed with the outboard face of the door on the surface of a cavity component of foam tooling. A retainer of rigid load supporting material is placed in the mold tooling with an access hole formed therein which corresponds to the area of the door. The location of the retainer hole is selected such that the back of the door will be accessible from the back of a completed instrument panel component when the door is molded in situ therewith. The skin, door and retainer are then foamed by directing foam precursors therebetween. The skin layer of the instrument panel is then removed at the retainer access opening thereby to expose the back of the door to an air cushion subject to deployment upon vehicle impact. When the air cushion deploys it will impact against the back surface of the door to cause it to lift from the instrument panel up and out of the pocket in the instrument panel component so as to allow the air cushion to deploy into the passenger compartment without requiring that the skin cover of the molded part be prescored, weakened or ruptured to affect the air cushion release. Brief Description of the Drawings In the accompanying drawings: Figure 1 is a perspective view of an instrument panel including the door construction of the present invention; Fig. 2 is an enlarged perspective view, partially sectioned showing the instrument panel and door combination of the present invention along the line 2-2 of Figure 1 looking in the direction of the arrows; Fig. 2A is a view similar to Fig. 2, but showing an inflatable bag deployed; Figs. 3-3c are schematic views of the method used to fabricate the constructions shown in Figs. 1 and 2; and Figs. 4 and 5 show different door, access opening and skin pocket configurations available for use in practicing the method and in the finished product of the present invention. Detailed Description of Preferred Embodiment Referring now to Figs. 1 and 2, a vehicle compartment 10 is shown having an interior trim component representatively shown as an instrument panel 12. For purposes of discussion the invention will be incorporated in the illustrated instrument panel 12 with it being understood that both the method and product formed by the method of the present invention are equally suitable for use with other vehicle components including door panels, consoles and headliner components. The instrument panel 12 more particularly includes an upper surface 14 which is located forwardly and below the front windshield 16 of the vehicle. The upper surface 14 is formed by an outer skin layer 18 which in one working embodiment is made from a relatively soft polyvinyl chloride resin material (PVC). The outer skin layer 18 has a door 20 located therein which closes a skin opening 22 to enclose an air cushion assembly 24 of a known type which has an inflatable bag 26 deployable through the outer skin layer 18 up and away from the windshield to protect a vehicle passenger upon vehicle impact. In accordance with one aspect of the present invention the door 20 is molded in situ with the instrument panel 12 so as to define a precise form and fit relationship between the door and the instrument panel 12 at the opening 22 therein. Furthermore, the in situ molding process is accomplished by steps which enable the door 20 to separate from the rest of the instrument panel 12 during deployment of a bag portion 26 of the air cushion assembly 24 without breaking up the instrument panel in a manner which will produce undesirable generation of particles and debris as the bag 26 expands into the passenger compartment 10. In the broadest aspect the inventive method integrally molds a pre-assembled door 20 having an inboard wall 28 of light impact resistant material such as aluminum or other suitable high strength material. The door 20 includes an outer shell or a PVC skin 30 material which can be of a similar softness and appearance as the skin 18 of the instrument panel 12. The skin 30 and wall 28 are bonded together by a layer of foamed urethane material which is foam molded by known methods in which the urethane foam precursors are injected into the space between the skin 30 and wall 28 in known reaction injection molding systems. The preassembled door 20 is loaded into mold tooling 32 and the plastic instrument panel 12 is molded about and over the back surface of the door leaving the outer surface 34 thereof as a continuation of the surface 14 for appearance. In the process the instrument panel 12 has a portion thereof removed to expose the door to the bag 26 as it is deployed into the passenger compartment 10. In particular, the method is characterized by removing a portion 36 of the instrument panel 12 as shown in Fig. 2 in broken line outline to make the opening for access to the door smaller in area than the area of the door 20. Referring now to Figures 3-3C, the method of the present invention includes the steps of loading the door 20 into a pocket 38 formed in a preformed outer skin 18. The door 20 and outer skin 18 are then loaded onto the surface 39 of a cavity part 40 of the mold tooling 32 as is best seen in Fig. 3. As shown in Pig. 2, if desired a marginal side 42 of the door 20 can be captured by a recessed segment 44 of the skin 18 to form a die-locked joint 46 between the door 20 and the skin 18 which holds the door 20 in place in the finished product and which includes an overlying strip segment 48 which masks any imperfections in the fit and finish of the door 20 and instrument panel 12 at the upper outer surface 14 thereof. Once the door 20 and skin 18 are placed into the cavity part 40 an instrument panel retainer 50 is loaded into the cavity part 40 and is held in spaced relationship with the skin 18 and door 20 by suitable means well known in the art of reaction injection molding. Foam precursors are then directed into the space between the retainer 50 and the skin 18 to be reacted and foamed to form a foam layer 52 between the skin 18, pocketed door 20 and the spaced retainer 50. In the preferred process the retainer 50 is preformed with an access hole 54 therein which is in alignment with the pocketed door 20 to provide access thereto through the retainer 50. A suitable barrier member 56 closes the hole 54 during the foaming process. Once the pocketed door 20 is foamed the process includes the steps of removing a segment 56a of the skin 18 and a part 58 of the foam layer 52 so as to expose the back surface or inboard face 60 of the door to the bag 26 during deployment. Such deployment preferably takes place through an opening 62 in the instrument panel 12 which is smaller than the area of the door 20 so as to impose an initially higher unit force on the door 20 as the bag 26 moves upwardly and outwardly of its housing 64 as shown in Fig. 2 and 2A. The greater unit force allows the nose portion 42 to flex upwardly to form a fulcrum about which the door 20 pivots in the direction of the windshield thereby defining a full unimpeded deployment of the bag 26 upwardly and forwardly of the windshield 16 without production of unnecessary debris. During operation of the door 20, a tether 66 connected between the door 20 and the retainer 50 will prevent separate flight of the door 20 into the passenger compartment. The resultant door and instrument panel assembly 70 includes ledges 72, 74 formed integrally of the instrument panel by shell edges 76, 78 resulting from removal of the skin segment 56a and the foam segment 58 to form the access opening 60 to the backside of the door 20. As shown in Figs. 4 and 5 the door can have different shapes and greater or lessor amounts of overlap by die-locked segments. For example in Fig. 4 the marginal edges 20a-20d of the door are all overlapped by die-locked segments 82a-82d respectively. In Figure 5 only end marginal edges 20c-20d are overlapped by die-locked segments 84a-84b. The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore, to be understood that within the invention other forms can be practiced other than as specifically described herein and yet remain within the scope of the appended claims.

Claims: A method for integrally molding a preassembled door (20) within a plastic panel (12) of an interior trim product for an automobile wherein the plastic panel (12) has an inboard surface and an outer appearance surface comprising the steps of: molding the plastic panel (12) about and over the pre-assembled door (20) so as to expose the door (20) in the appearance surface of the plastic panel (12), and removing a portion (56a, 58) of the plastic panel (12) overlying the door (20) to define an opening (62) therein to expose the door (20) for operation from inboard thereof. A method according to claim 1, wherein the dimensions of said portion (56a, 58) removed make said opening (62) smaller in periphery than the periphery of the door (20). A method according to claim 1, wherein the plastic panel (12) is a foamed member having an outer skin (18) and the method further comprises molding the plastic panel (12) about and over the door (20) as aforesaid by placing the door (20) in a pocket (38) of the outer skin (18) in a mold cavity after which the panel (12) is foamed with a layer (52) of foam material to encapsulate the inboard face (60) and sides (20a-20d) of the door (20) while leaving the outboard face thereof exposed and form fit with the surrounding outer skin (18) of the panel (12), the portion (56a, 58) being removed as aforesaid. A method according to claim 1, and further comprising preforming an outer skin (18) for the plastic panel (12) to have a pocket (38) therein with die-lockable segments (44) forming at least a part of the perimeter of the pocket (38); loading the pre-assembled door (20) in the pocket (38) with the die-lockable segments (44) overlapping at least a part (12c, 12d) of the periphery of the door (20); and placing the pocketed door (20) and the outer skin (18) in a foaming mold (32) and foaming the outer skin (18) behind and around the periphery of the door (20) to form an integral door (20) and panel (12) product, the portion (56a, 58) being removed as aforesaid. A method according to claim 3 or 4, wherein the outer skin (18) and the foamed layer (52) thereof are formed as an instrument panel (12) having a flat upper surface (14) adapted to be located below and inside a front vehicle windshield (16) and the preassembled door (20) is pocketed in the upper surface (14) for release from the instrument panel (12) in a swinging movement about one of the edges (12a-12d) of the door (20). A method according to claim 1, wherein the plastic panel (12) includes an outer skin (18); and the outer skin (18) is preformed to have a pocket (38) to receive the preassembled door (20) in the step of molding the panel (12) about and over the door (20). A method according to claim 6, wherein the outer skin (18) is preformed to have die lockable edges (44, 82, 84) around the pocket (38) overlapping at least a portion (12c, 12d) of the periphery of the door (20) to retain the door (20) securely within the outer skin (18) following molding of the panel (12) about and over the door. A cover for an air cushion device (24) deployable into a passenger compartment (10) to protect vehicle passengers upon vehicle impact, said cover comprising an interior trim panel (12) and a door (20) in an opening (22) in the panel (12), characterized by the door (20) being formed in situ of the panel (12) in a close tolerance form and fit relationship therewith and means including die lockable segments (44, 82, 84) on the panel (12) for retaining the door (20) in the panel (12) while masking edge imperfections either in form or fit around the periphery of the door (20). A cover according to claim 8, wherein the interior trim panel (12) is an instrument panel having an upper surface (14) adapted to be located below and inboard of a front windshield (16) of a vehicle; and said upper surface (14) has segments (44, 82, 84) thereon overlapping at least a part of the periphery (20a-20d) of said door (20) to secure it with respect to the instrument panel (12). A cover according to claim 8, wherein said die lockable segments (44, 82, 84) include interior trim panel edge segments (44, 82, 84) overlapping at least a part of the periphery (20a-20d) of said door (20). A cover according to claim 10, wherein said panel (12) has a rear access opening (62) smaller than said door (20) and means including said edge segments (44, 82, 84) to form a common perimeter defining the zone through which an air cushion device (26) is deployable upon vehicle impact and wherein the door (20) is separable from the panel (12) as a unit by impact through the rear access opening (62). A cover according to claim 11, wherein said panel (12) constitutes an instrument panel (12) having an upper surface (14) located below and inboard of the front windshield (16) of a vehicle and wherein said door (20) is located in said upper surface (14). A cover according to claim 11, wherein said panel (12) includes an outer skin (18) of flexible material having a pocket (38) formed therein for receiving said door (20) and a layer (52) of foam material fillingly encircling the outer periphery of said pocket (38), to form said overlapping segments (44, 82, 84) for holding the door (20) in place; said outer skin (18) and foam material (52) forming said overlapping segments (44, 82, 84) being resilient to yield upon application of a release force on the door (20) to cause it to separate from the panel (12) upon actuation of said air cushion device (26). A cover according to claim 13, wherein said panel (12) includes spaced ledges (72, 74) formed by segments of said outer skin (18) and said foam material (52) to support the inboard surface (60) of said door (20) with respect to said panel (12); and means (44) forming a surface on said outer skin (18) to define a fulcrum for pivotal movement of said door (20) when it is released from said panel (12) upon actuation of said air cushion device (26).

Inventors: BLEAU GEORGE, PARKER KENT LEE ROOM BUCHANAN, BLEAU, GEORGE, PARKER, KENT LEE, ROOM 303 BUCHANAN HALL
Applicants: DAVIDSON TEXTRON INC, DAVIDSON TEXTRON INC.
Application year: 1990
Main classification: B29C45
IPC codes: B29C44, B60R21, B29C45, B29C69