Machine element or mechanism – Control lever and linkage systems – Elements
Reexamination Certificate
2002-03-13
2004-01-13
Bucci, David A. (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Elements
C280S731000
Reexamination Certificate
active
06675675
ABSTRACT:
BACKGROUND
The invention relates to a steering wheel having a latching element for latching an airbag module to the steering wheel body and an electric contact.
Airbag units serve to protect a motor-vehicle occupant and these days usually form part of the standard equipment of a motor vehicle. Since installation of the airbag unit via screws has proven very complicated, various options for fastening it via latching connections have been proposed.
DE 296 02 630 describes a latching device for fastening an airbag module to a vehicle part, the latching device being designed in such a manner that pressing-on and/or rotating the airbag module causes a locking body to engage in a correspondingly shaped mating piece and the airbag module is thus fixed on the vehicle part. As the locking body, one exemplary embodiment provides a bent piece of spring steel which is wound around a cylindrical projection and can snap into a hook on a steering wheel body.
DE 296 21 295 discloses a device for fastening an airbag module in the steering wheel with at least one passive latching element and a pivotable or displaceable, rigid component as the active latching element, one element of which is provided on the steering wheel and the other element of which is provided on the airbag module. A resiliently mounted, pivotable hook is also suitable as the active latching element.
DE 195 08 816 describes an arrangement for fastening an airbag module to a steering wheel body, in which the mounting takes place by means of a bolt engaging in a resilient latch. In one embodiment, hooks are provided on the airbag module and leg springs on the steering wheel, the hooks being latched to a leg of the spring.
DE 197 25 684 discloses a steering wheel having an airbag module which is fastened to the steering wheel body by means of a latching connection, the latching connection having a resilient element which is tensioned during the installation process and snaps back into the fixing position when the latching takes place. This element is formed on the steering wheel or the airbag unit by a pretensioned wire ring which is secured to hook-shaped formations. Formations which push away the wire ring counter to its pretensioning during the installation and become hooked on the wire ring in the fixing position are provided on the airbag unit and on the steering wheel.
U.S. Pat. No. 5,350,190 describes connecting elements between an airbag module and a steering wheel, which elements enable the airbag module to move toward the steering wheel and away from the steering wheel. The connecting elements consist in each case of two parts, the first part being connected to the steering wheel and the second to the airbag module. The two parts engage telescopically in one another, are secured against slipping apart by an annular lip and can be latched in one another by this lip. The two parts are pretensioned with respect to each other, for example by a spring. These types of fastening do ensure simplified installation of the airbag unit. However, the arrangement of the airbag unit in the center of a steering wheel conceals a further problem. This is because usually the horn signal, which is intended to enable the driver to issue a warning signal in critical situations, is triggered by the pressure on the center of the steering wheel of the vehicle. In this case, at least a subregion of a covering is moved in the direction of the steering wheel body and an electric switching contact is therefore short-circuited.
U.S. Pat. No. 5,350,190 describes connecting elements between an airbag module and a steering wheel, which elements enable the airbag module to move toward the steering wheel and away from the steering wheel. The connecting elements consist in each case of two parts, the first part being connected to the steering wheel and the second to the airbag module. The two parts engage telescopically in one another, are secured against slipping apart by an annular lip and can be latched in one another by this lip. The two parts are pretensioned with respect to each other, for example by a spring. These types of fastening do ensure simplified installation of the airbag unit. However, the arrangement of the airbag unit in the center of a steering wheel conceals a further problem, because usually the horn signal, which is intended to enable the driver to issue a warning signal in critical situations, is triggered by the pressure on the center of the steering wheel of the vehicle. As a result, at least a subregion of a covering is moved in the direction of the steering wheel body and an electric switching contact is therefore short-circuited.
The arrangement of airbag units in the steering wheel causes problems with regard to the spatial arrangement of the contacts for triggering the horn. Although separate actuating levers, for example combined with switching levers for the light or windshield wipers, are used at discrete locations, they have proven disadvantageous, since the driver is not used to this and therefore requires an excessive amount of time in order to trigger the horn signal.
One attempt to solve this problem involves the “floating horn” principle. In this case, the airbag unit is arranged on the steering wheel in such a manner that a pressure exerted by the driver on the airbag unit causes the horn signal to be triggered. Usually in this case, one contact is arranged on the airbag unit and one on the steering wheel and the airbag unit is connected to the steering wheel via flexible components. As a result, when a pressure is exerted on the airbag unit, movement of the airbag unit toward the steering wheel causes the contacts to be short-circuited and the horn to therefore be triggered.
Usually, the (electrically conductive) steering wheel frame or the generator support of the airbag unit form a first contact, and a corresponding, second contact is provided on the respective other part. In many cases, an additional contact bridge is arranged as the contact on the steering wheel.
In all of the above-described devices for latching an airbag unit to a steering wheel, additional parts have to be provided if the airbag unit is to be used according to the “floating horn” principle for triggering the horn.
It is therefore desirable, in the case of an airbag fastening according to the “floating horn” principle, to further reduce the number of required parts and, in the process, to make it possible at the same time to secure the airbag unit to the steering wheel body in a manner which is simple, secure and can be carried out without a tool.
SUMMARY OF THE INVENTION
This object is achieved by provision of a steering wheel having a latching element for latching an airbag module to the steering wheel body and an electric contact.
According to an embodiment of the present invention a steering wheel having a steering wheel body, an airbag unit, a latching connection for securing the airbag unit to the steering wheel body, and a contact device is provided. That contact device may include at least one first and one second contact which, in order to trigger an electric functional element, in particular an electric horn, are short-circuited if the airbag unit is moved in the direction of the steering wheel body by a pressure exerted on said airbag unit. The first contact may be a component of a latching element of the latching connection, and the latching element may be formed by a wire element.
For this purpose, the wire element of the latching connection is at least partially electrically conductive and at the same time forms a first contact of the contact device.
In this embodiment, the airbag unit is preferably secured to the steering wheel frame of part of the steering wheel body. However, in general steering wheel body is understood to mean the entire steering wheel without an airbag unit.
It is preferred for at least one elastic spacer element for setting a distance between the steering wheel body and the airbag unit to be provided. The spacer element can be deformed by a pressure being exerted on the airbag unit, as a result of whic
Hans Andreas
Sauer Frank
Bucci David A.
Foley & Lardner
McAnulty Timothy
Takata-Petri AG
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