The invention herein relates to an automobile steering column switch comprising a support, which can be mounted to a steering column tube of an automobile steering column, said support having arranged on it at least one wiper switch and/or blinker switch and/or driving light switch.
As has been known, motor vehicles consist of a plurality of complex construction assemblies, whereby the steering column switch assembly to be installed on the steering column tube of the motor vehicle represents an important feature.
Typically, steering column switches are mounted in radial direction relative to the steering column on the steering column""s steering column tube, thereby rendering the steering column switch immobile relative to the steering wheel when the steering wheel and hence the steering column guided inside the steering column tube are moved. As a rule, the steering column switch comprises a blinker switch and a driving light switch, in which case the driving light switch frequently is configured as a rotary switch being an integral part of the switch lever of the blinker switch. Furthermore, the steering column switch frequently comprises a wiper switch for graduated activation of the windshield wipers and activation of the switch functions for the windshield washer system. For example, such steering column switches have been known from DE Auslegeschrift 2,810,790 and DE Patent 3,532,532 C2.
Every steering column switch comprises a plurality of interacting components that perform a large number of switch functions. These components are accommodated in an extremely small space and, therefore, make the construction of the steering column switch complex. Therefore, depending on the type of vehicle, individual components are more or less pre-assembled and subsequently mounted to a support located on the steering column tube of the steering column.
A similar situation exists in the case of an ignition starter switch with integrated steering lock because the ignition starter switch frequently performs two additional switch functions such as, for example, activation of an immobilizer cooperating with a transponder integrated in the ignition key. As a result, ignition starter switches are becoming more and more complex because integrated code-recognition systems are to protect the vehicle against unauthorized use.
The two assemblies, namely the steering column switch and the ignition starter switch, are mounted separately to the steering column tube at the time the motor vehicle is assembled, whereby, in most cases, the ignition starter switch is located at a distance from the steering column switch. However, considering the viewpoint of technology, the automobile industry has demanded reduced assembly times for motor vehicles, in particular on the assembly line.
The problem to be solved by the invention herein is to provide an automobile steering column switch of the above-described type, in which case said switch can be pre-assembled practically completely and can incorporate the switch functions of an ignition starter switch.
In accordance with the invention herein, this problem has been solved in that
the support comprises an integrated printed circuit board provided with electrical contacts to which the switch functions relating to the wiper switch and/or blinker switch and/or driving light switch and an ignition starter switch can be transferred,
said support is configured in one piece with an accommodation space for the ignition starter switch, and
said support can be mounted, together with the switches, as pre-assembled module to the steering column tube.
Consequently, the support of the steering column switch not only accommodates the printed circuit board for performing the switch functions of the steering column switch and the ignition starter switch but also is configured in such a manner that it can accommodate the ignition starter switch. Therefore, all of the switch functions combined are transferred as one single function to the printed circuit board provided in the steering column switch. As a result, it is no longer necessary to install a plurality of electrical cables in the steering column switch, said cables taking up an unnecessary amount of space and being prone to trouble. In addition, the electrical cable connections of the ignition starter switch are eliminated because its switch functions are now transferred directly to the printed circuit board on the support. The particular advantage of this is that the pre-assembled ignition starter switch can be inserted in one piece in the respective accommodation space on the support of the already pre-assembled steering column switch. The steering column switch may then be mounted in the form of a module to the steering column of the motor vehicle. Consequently, this reduces the number of required components, the required assembly facilities, as well as the assembly time on the assembly line during the preliminary and final assemblies of the motor vehicle. Therefore, a separation of mechanical and electrical assembly functions has been created.
As an alternative, this problem has also been solved in thatxe2x80x94the support comprises a printed circuit board with electrical contacts, to which the switch functions relating to the wiper switch and/or the blinker switch and/or the driving light switch, as well as an ignition starter switch, can be transferred,
the support can be mounted as pre-assembled module to the steering column tube, and
the ignition starter switch can be mounted as a pre-assembled module to the steering column tube, separately from the support, by means of a clamp connection.
Considering the printed circuit board and the combination of the switch functions of the steering column switch in conjunction with the ignition starter switch, this alternative solution offers the same advantages as the first solution. While in this case the ignition starter switch is not directly integrated in the support of the steering column switch, but rather mounted as a separately pre-assembled component on the steering column tube of the steering column in close proximity of the steering column switch, the switch functions of the ignition starter switch can be transferred directly to the printed circuit board mounted to the support due to its close proximity to this support. In order to simplify the assembly effort relating to the ignition starter switch provided as separate module and to allow fast assembly, the clamp connection consists of a clamp overlapping the steering column tube and a corresponding counter-clamp adjoining the ignition starter switch. In this case the clamp overlapping the steering column tube is connected with the counter-clamp on the ignition starter switch by means of screws. Due to this, only a few hand movements are required to mount the ignition starter switch quickly to the steering column tube.
In the case of an advantageous embodiment of the invention herein the wiper switch and/or blinker switch and or driving light switch are mounted to the support by means of clip connections. These become a fixed integral part of the support simply by inserting the switch in the respective accommodation space on the support. As a result, these clip connections may be released conveniently for repair and maintenance purposes, thereby permitting the quick and easy removal of the switches from their respective accommodation spaces.
In order to reduce assembly efforts even further, one modification of the invention herein provides that the support be mounted in position to the steering column tube by means of a clip connection or bayonet connection, whereby the support rests on a ball-bearing located on the steering column. This ball-bearing is placed in the support of the steering column switch during preliminary assembly and placed on the steering column at the time of assembly in such a manner that, due to the clip connection or bayonet connection between the support and the steering column tube, the steering column switch is mounted rigidly on said steering column tube.
In accordance with another modification of the solutions offered by the invention herein the electrical contacts of the printed circuit board are configured as micro-switches. These micro-switches can have multiple functions, be subjected to frequent use, and are resistant to mechanical stress and distinguished by high reliability. As an alternative, as has been well known, the said electrical contacts of the printed circuit board may be configured as switch contacts or the like.
In order to be able to convert switch functions transferred to the printed circuit board in an effective manner, the circuit board is connected with a computer-controlled electronic control system of the automobile. In addition, the printed circuit board is covered with a lid that is mounted to the support. As a result of this, the printed circuit board is protected against outside influences such as damage caused by moisture and dust.
Frequently, switch contacts located inside the steering column switch are subject to corrosion or breakage due to excessive use. To prevent this and achieve greater reliability, the ignition starter switch preferably comprises a cam control activated by means of a key, said cam control acting on the electrical contacts of the printed circuit board. Therefore, different configurations of the cams activate different switch functions that are transferred to the printed circuit board in the support of the steering column switch.
It is useful if the support incorporates an electrical transfer system for an airbag device. As a rule, this type of transfer system comprises a helical volute buffer spring used as electrical connection element between two parts, which move relative to each other; this is the case with a steering wheel containing an airbag and moving relative to the steering column switch. In as much as the electrical transfer system is also an integral part of the pre-assembled steering column switch module, the assembly effort is reduced even further.