Passenger-side airbag module darted end caps

Abstract: The screws which are normally employed to attach the end plates (24, 26) to the trough-shaped main body (12) of a passenger-side airbag module reaction canister (10) are replaced by darts (30) impact-driven into cylindrical preparations (20). The darts are made of a material harder than that of the main body and include surface irregularities which deform the material of the main body and improve the frictional engagement.

Description: This invention relates to motor vehicle airbag modules. More particularly, it relates to the construction of the reaction canister of a passenger-side airbag module. The passenger-side airbag module of a motor vehicle normally includes a reaction canister which houses an inflator and a folded airbag. Customarily, the reaction canister is in the form of a trough having a floor and a pair of spaced sidewalls. This main body is often formed from an extrusion of, for example, aluminum or plastic which is then cut to the desired length. It often includes screw preparations which are elongated channels running along its length. The ends of the main body are closed by means of end plates. The end plates are fastened to the main body by means of screws. Each screw extends through an opening in the end plate and into the main body. Customarily, the screws thread into the ends of the screw preparations. Several screws are required to be threaded from each of the end plates into the main body of the reaction canister. As a consequence, the assembly of such a reaction canister is rather time consuming and labor intensive (see CA-A-2122958). The present invention consists in an automotive airbag module including a trough-shaped reaction canister of the type having an extruded main body with first and second ends, including spaced parallel sidewalls joined by a floor, and first and second end plates closing the respective first and second ends, characterised by: a plurality of darts extending from each of said end plates, the darts being impact-driven into the respective first or second end of said main body, each of said darts being of a material having a hardness greater than that of said main body and carrying surface irregularities making increased friction engagement with the material of said body. It is possible by means of the present invention to simplify the assembly of a passenger-side reaction canister and to reduce the cost of such assembly. The linearly impact-driven "darts" which in accordance with the present invention are substituted for the screws formerly employed in attaching the end plates of a reaction canister to its main body are elongated pins made of a material harder than that of the main body. Their surfaces include irregularities which deform and engage the material from which the main body is extruded. This results in a high friction engagement between the dart and the main body. Preferred embodiments of the invention will now be described with reference to the accompanying drawings, wherein: FIG. 1 is an isometric view, partially exploded, illustrating the attachment of the end caps to the main body of a reaction canister; FIG. 2 illustrates a dart usable in this invention; FIG. 3 illustrates a modified dart in accordance with this invention; FIG. 4 is a plan view of a still further modification of a dart; FIG. 5 is a side view of the dart of FIG. 4 ; FIG. 6 is a cross-section of the dart of FIGS. 4 and 5 illustrating its insertion into a screw preparation; and FIG. 7 is a view similar to FIG. 6 illustrating the dart rotated into a locking position. Referring to FIG. 1 , there is illustrated a reaction canister 10 for a passenger-side airbag module. It comprises a main body 12 in the form of a trough having spaced parallel sidewalls 14, 16 and a floor 18 . The floor is rounded to receive a cylindrical inflator and a folded airbag would normally be retained between the sidewalls 14, 16 . As these elements form no part of the invention, they are not illustrated. The main body 12 may be extruded from a material such as plastic or aluminum and cut to the desired length. In the embodiment which is illustrated, the main body is extruded with screw preparations 20 on its external surface. The screw preparations are essentially tubular cylinders having longitudinal slots 22 . The ends of the main body 12 are closed by end plates 24, 26 . The end plates are provided with mounting holes 28 which are aligned with the respective screw preparations 20 . The prior art practice has been to mount these end plates to the ends of the main body by means of screws passing through the mounting holes 28 and threaded into the screw preparations 20 . This is a rather time-consuming and labor-intensive procedure, as each screw in turn must be turned and tightened. In accordance with the present invention, the screws heretofore used are replaced by "darts" 30 . The darts 30 are impact-driven linearly into portions of the main body 12 , such as the cylindrical channels at the ends of the screw preparations 20 . The darts 30 are characterized by having a hardness greater than that of the material from which the main body 12 is made. In addition, they make interference fits with the end openings of the screw preparations 20 and have surface irregularities which deform the inner surfaces of the screw preparations. This creates a high friction engagement between each dart and the main body which retains the end plates. FIG. 2 illustrates one form of dart which would be usable with this invention. It comprises a shank 30 having an enlarged head 32 . The shank 30 has surface irregularities in the form of a plurality of substantially frusto-conical surfaces 34 forming shoulders 36 having diameters greater than the shank 30 . A modified form of dart is illustrated in FIG. 3 . This modification also includes a shank 38 having an enlarged head 40 . The surface irregularities, however, comprise a pair of lands 42a and 42b having V-shaped cross-sections circling the shank 38 at a shallow angle to the shank axis. This modification may also be impact-driven linearly into the screw preparation 20 . However, the encircling lands will impart a slight amount of self-rotation as the dart advances. Both the FIG. 2 and FIG. 3 versions illustrate darts which may be linearly impact-driven into the main body 18 to form a high friction securement without further manipulation. A suitable dart could be an article such as a concrete nail having a shank with an irregular surface. A somewhat different modification is illustrated in FIGS. 4 and 5 . This modification also includes a shank 44 having an enlarged head 46 . The head, however, is provided with a slot 48 for reasons which will be explained. In this modification, the surface irregularities are in the form of a plurality of sharpened ribs 50 which lie along one side of the shank 44 and which are helically aligned -- resembling segments of a screw thread. The operation of this modification is illustrated in FIGS. 6 and 7 . It is designed specifically for use in a screw preparation 20 having the slot 22 (or an equivalent construction, such as a key-shaped hole). It is impact-driven into the channel of the screw preparation 20 with the ribs 50 lying within the slot 22 as shown in FIG. 6 . In this configuration, it may be impact-driven its full length into the screw preparation. Thereafter, it may be rotated by a screwdriver or similar device, as illustrated in FIG. 7 , so that the sharpened ribs 50 bite into the softer material of the screw preparation 20 , locking it into position. This modification achieves two additional advantages. The first is that the helical path of the ribs 50 creates a positive clamping force as the shank 44 is forced into the screw preparation as a result of the helical path of the ribs. The second is that the dart may be more easily removed, if necessary, by a reverse turn to align the ribs 50 in the slot 22 , allowing the dart to be simply out. In the invention as illustrated, the darts 30 in their various modifications are independent members which may be impact-driven into the main body 12 either individually, or simultaneously as a group. It will also be apparent, however, that the heads of the darts of all but the FIGS. 4 and 5 versions could be molded or otherwise secured in the bodies of the respective end plates. In fact, the heads could be completely eliminated and the shank portions could be formed integrally with the end plates.

Claims: An automotive airbag module including a trough-shaped reaction canister (10) of the type having an extruded main body (12) with first and second ends, including spaced parallel sidewalls (14, 16) joined by a floor (18), and first and second end plates (24, 26) closing the respective first and second ends, characterised by: a plurality of darts (30) extending from each of said end plates, the darts being impact-driven into the respective first or second end of said main body, each of said darts being of a material having a hardness greater than that of said main body and carrying surface irregularities making increased friction engagement with the material of said body. An airbag module according to claim 1 wherein said main body (12) includes preparations (20) extending along its length, each defining first and second substantially cylindrical channels at the respective first and second end of the main body, each of said channels receiving one of said darts (30) therein. An airbag module according to claim 2 wherein each of said preparations (20) defines a slot (22) along its length extending into said cylindrical channel and wherein the surface irregularities on each of said darts (30) include a protrusion (50) which extends into said slot upon the impact driving of said dart but is then displaced into said preparation by rotation of the dart. An airbag module according to any preceding claim wherein each of said darts (30) is a separate entity from its respective end plate (24, 26), extends through an opening (28) in said end plate into said main body (12), and includes an enlarged head (32, 40, 46) engaging the surface of said end plate. A method of assembling an automotive airbag module which comprises: providing a trough-shaped extrusion having spaced first and second sidewalls joined by a floor; cutting said extrusion to form a trough-shaped main body (12) of desired length having spaced first and second sidewalls (14, 16) joined by a floor (18) and first and second ends; providing first and second end plates (24, 26) adapted to close the respective first and second ends of said main body; providing a plurality of darts (30) extending from each of said end plates, each constructed of a material harder than that of said main body and having a shank (30, 38, 44) carrying surface irregularities (36, 42a, 42b, 50); and linearly impact-driving each of said darts into the respective first or second end of said main body to seat each end plate against said main body while thereby deforming the material of said main body to improve the frictional engagement between said dart and main body. A method of assembling an automotive airbag module which comprises: providing a trough-shaped extrusion having first spaced first and second sidewalls joined by a floor; cutting said extrusion to form a trough-shaped main body (12) of desired length having spaced first and second sidewalls (14, 16) joined by a floor (18), and first and second ends; providing first and second end plates (24, 26) adapted to close the respective first and seconds ends of said main body; providing a plurality of darts (30), each constructed of a material harder than that of said main body, having an enlarged head (32, 40), and a shank (30, 38) carrying surface irregularities (34, 42a, 42b); and linearly impact-driving each of said darts through one of said end plates and into the respective first or second end of said main body to seat its head against said one end plate while thereby deforming the material of said main body to improve the frictional engagement between said dart and main body. A method of assembling an automotive airbag module which comprises: providing a trough-shaped extrusion having spaced first and second sidewalls joined by a floor and having substantially cylindrical screw preparations (20) therealong defining substantially cylindrical channels with a longitudinal slot (22) extending into each of said channels; cutting said extrusion to form a trough-shaped main body (12) of desired length having spaced first and second sidewalls (14, 16) joined by a floor (18) and including portions of each of said screw preparations therealong, and first and second ends, each end including ends of said screw preparation portions; providing first and second end plates (24, 26) adapted to close the respective first and second ends of said main body; providing a plurality of darts, each constructed of a material harder than that of said main body, having an enlarged head (46), and a shank (44) carrying sharpened helical ribs (50) along one side to form a plurality of aligned ribs dimensioned to fit within the slot of one of said screw preparation portions; linearly impact-driving each of said dart through one of said end plates and into the respective first or second end of the channel of one of said screw preparation portions on said main body to seat its head against said one end plate with said ribs being positioned within said slot; and rotating each of said darts to advance its ribs into, and thereby deform the material of said main body to improve the frictional engagement between said dart and main body.

Inventors: DAVIS TERRY R, JARBOE PATRICK G, RAVENBERG MICHAEL J, DAVIS, TERRY R., JARBOE, PATRICK G., RAVENBERG, MICHAEL J.
Applicants: MORTON INT INC, MORTON INTERNATIONAL, INC.
Application year: 1995
Main classification: B60R21
IPC codes: F16B21, B60R21