Machine element or mechanism – Control lever and linkage systems – Elements
Reexamination Certificate
1999-04-08
2001-07-17
Luong, Vinh T. (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Elements
C403S256000, C403S359500, C403S374300
Reexamination Certificate
active
06260437
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to a steering wheel component for a motor vehicle and more particularly, to a back mounting plate assembly for use in mounting a steering wheel to a steering wheel shaft via a side fastener column attachment.
BACKGROUND OF THE INVENTION
One assembly in a passenger vehicle is a steering wheel assembly which permits a driver to accurately steer the vehicle. Typically, the steering wheel assembly includes an upper assembly comprising a steering wheel hub mounted to a steering shaft which is enclosed in a steering wheel column. In the past, the steering wheel hub has been attached to the steering wheel shaft in a variety of ways and in most typical procedures, a fastener is used to mount the two components to one another. For example, the steering wheel hub may include a rear mounting plate having opposing sides in which an upper end of the steering wheel shaft is received at a first side. The upper end of the steering wheel shaft comprises a threaded portion which is attached to the rear mounting plate by fastening, e.g., bolting, the upper end to the rear mounting plate. This is usually done by threading a nut at a second side of the rear mounting plate to attach the two components to one another.
Most passenger vehicles have a driver's side air bag mounted to the steering wheel. The air bag assembly includes an air bag module that is disposed within the steering wheel assembly. The air bag module includes a mating connector which mates with a corresponding connector disposed at the rear mounting plate when the two are assembled. After attaching the rear mounting plate to the steering wheel shaft, the air bag module typically attaches to and mates with the second side of the rear mounting plate. The air bag module is secured to the rear mounting plate of the steering wheel by a plurality of fasteners.
During the attachment of the steering wheel hub to the steering wheel, access to the second side of the rear mounting plate is necessary so that the assembler may attach the upper end of the steering wheel shaft to the rear mounting plate by threading a bolt around the upper end of the steering wheel shaft. In another embodiment, the steering wheel assembly and the air bag assembly are partially combined and the steering wheel assembly comprises a steering wheel hub including a front mounting plate, wherein the air bag module is disposed within the steering wheel hub adjacent one side of the front mounting plate. A first connector extends from the front mounting plate and mates with a connector provided on a rear mounting plate. The rear mounting plate is attached to the upper end of the steering wheel shaft with a fastener. Next, the front and rear mounting plates mate with another and are mounted to one another via a plurality of fasteners. In this second embodiment and similar to the first steering wheel assembly, complete access to the rear mounting plate is necessary so that the assembler may receive the steering shaft on one side of the rear mounting plate and fasten the two together at a second side.
Because the steering wheel assembly typically comprises at least two components and the front and rear mounting plates are separated and not attached to one another until after the rear mounting plate is attached to the steering shaft, the overall assembly process is multi-component based which increases the time and cost to assemble the steering wheel assembly to the steering shaft.
SUMMARY OF THE INVENTION
The present invention comprises a steering wheel attachment assembly and a method of removably coupling the steering wheel attachment to a steering wheel shaft in a cost effective and convenient manner. More particularly, in one aspect the present invention is directed to a back mounting plate for attachment to a steering wheel module. Accordingly, the present steering wheel attachment assembly permits a steering wheel module to be supplied to the assembler in a fully assembled state prior to coupling the steering wheel module to the steering wheel shaft. In an exemplary embodiment, the back mounting plate includes lateral portions which define a mounting platform. The mounting platform preferably has a plurality of openings to receive fasteners for attaching the back mounting plate to a front mounting plate which is typically one component of the steering wheel module. The back mounting plate preferably has a recessed center portion intermediate the lateral portions with the recessed center portion including a base platform having a center opening formed therein. Formed within the base platform is a trough which extends from a first side of the back mounting plate to the center opening.
Integrally formed within the back mounting plate is a hub which is disposed in the center opening formed in the base platform. Preferably, the hub is similarly shaped as the center opening so that a complementary fit results between the two members. The hub includes an opening formed in the center thereof, wherein the hub opening is axially aligned with the center opening resulting in access to the hub opening from exterior the back mounting plate when the hub is disposed within the back mounting plate. The hub opening receives one end of the steering wheel shaft. The hub further includes a side bore longitudinally extending from one end of the hub to the hub opening and the side bore is axially aligned with the trough formed in the base platform. The side bore and trough combination permit an assembler to gain access to the hub opening formed in the hub and more specifically, to the steering wheel shaft which is disposed therein during the assembly process.
Preferably, the hub opening formed in the hub is tapered at one end and is defined by a pair of opposing arcuate walls and by a pair of flats which extend between the opposing arcuate walls. The flats comprise planar surfaces which scat against complementary flats formed in the steering wheel shaft to prevent the steering wheel shaft from freely rotating within the hub opening under an application of torque to the steering wheel shaft. Because of the complementary nature between both pairs of flats, the flats also serve to locate the steering wheel shaft during insertion into the hub opening.
In accordance with the present invention, the steering wheel shaft is easily and removably coupled to the back mounting plate by first inserting the one end of the steering wheel shaft into the hub opening using the flats as guides. The steering wheel shaft also includes a recessed slot intermediate the pair of flats formed therein, wherein the recessed slot has a planar back surface. The recessed slot is formed relative to the pair of flats so that when the steering wheel shaft is inserted into the hub opening, the side bore opens into the recessed slot. To securely and removably couple the steering wheel shaft to the hub, the fastener is guided by the trough into the side bore and engages the planar back surface of the recessed slot. As the application of torque to the fastener continues and the fastener is driven into the recessed slot, the steering wheel shaft is itself driven toward the arcuate wall of the hub opposite the side bore. The driving of the fastener into the recessed slot results in an interference locking of the steeling wheel shaft within the hub. This interference locking action prevents the steering wheel shaft from being displaced in a direction away from the hub under an application of force. Furthermore, a taper lock results when the steering wheel shaft is driven into a wedge portion of the hub. This taper lock results in the steering wheel shaft being securely coupled to the back mounting plate.
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patent: 5816112 (1998-10-01), Hosoi et al.
patent: 5878629 (1999-03-01), Nagata et al.
patent: 5921147 (1999-07-01), Nagata et al.
patent: 6033145 (2000-03-01), Xu et al.
patent: 9407807 (1994-07-01), None
patent: 19616234 (1997-10-01), None
patent: 0769440 (1997-04-01), None
patent: 2608232 (1988-06-01), None
pate
Delphi Technologies Inc.
Luong Vinh T.
Marra Kathryn A.
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