Steering column switch

A steering column switch having a switch element and a switch lever, wherein the switch lever is designed from first and second modules. Because of the modular design, different grip pieces can be accommodated by the same switch element.

TECHNICAL FIELD

The invention generally relates to electrical switches and more particularly relates to steering column switches of a vehicle.

BACKGROUND OF THE INVENTION

EP-A-0 845 389 discloses a steering column switch with a housing, in which at least one operating lever is mounted to pivot and/or move, for which different types of operating levers with the corresponding contact device can be used during assembly. A mating contact device with a predefined number of switch functions that cooperates with the contact device of the operating lever is arranged in the housing of the steering column switch. The available choice of switch functions is a function of the type of operating lever to be installed and its contact device.

DE-A-43 32 748 also shows a steering column switch with a switch lever mounted to move, at least in one plane relative to the steering column, in a housing, which is in connection with switch elements arranged on a printed-circuit board for its activation. At least one of its switch elements is designed as a light-transmitting or light-receiving element in optical connection with a corresponding optical switch, operable by the switch lever.

DE 44 28 883 C1 discloses a steering column switch with a housing having mounts for single switches. The single switches comprise a switch housing, in which a switch lever is mounted to pivot. Guide elements are molded onto the switch housing for alignment in the correct position and holding in a mounting chamber of the housing. The switch housing also has clip elements for fastening of the switch in the corresponding mounting chambers. The switch is provided with function elements and is equipped with a printed-circuit board that is connected to a central circuit board of the steering column switch.

Steering column switches are also known, whose switches, integrated in a switch lever, are connected by corresponding wiring to a circuit board of the steering column switch, on which the switch lever is mounted in a two-part housing of the steering column switch, whose separation runs in the region of the switch lever. This type of switch lever must have corresponding free space available in its interior, in order to permit passage of the wiring, which requires relatively large dimensioning of the switch lever. Significant assembly expense is required for wiring within the switch lever, as well as from the switch lever to the corresponding circuit board. The steering column switches are pre-mounted together with the corresponding switch lever and then installed in the vehicle, so that a significant risk of damage to the switch lever exists during handling of the steering column switches.

The object of the invention is to devise a steering column switch of the initially mentioned type, which has various applications, in terms of functions, is inexpensive to manufacture and easy to handle during assembly.

The objective is realized according to the invention in that the switch lever is assembled from a foot cooperating with the switch element and a grip piece inserted into the foot.

Because of the two-part design of the switch lever, the switch mechanics of the steering column switch can be made cost effectively in a large number of pieces, regardless of its switching functions. Coordination of the switching functions to the steering column switch, provided with a central printed-circuit board, occurs by means of corresponding programming of the computer system of the vehicle. More specifically, the switch lever (grip piece) is coupled to the foot of the switch lever. Insertion of the grip piece into the foot can occur at the end of assembly of the steering column switch in the vehicle, for which reason the grip piece is only exposed to limited risk of damage during assembly. In addition, the arrangement of a one-part housing for the steering column switch is possible, which need only be provided with a corresponding opening for the grip piece. A visually pleasing effect is achieved with the one-part housing.

In a steering column switch of the initially mentioned type, with at least one additional switch integrated in the switch lever of the single switch, the objective according to the invention is realized in that the switch lever is assembled from a foot cooperating with the switch element and a grip piece inserted into the foot, wherein the end of the grip piece inserted into the foot has contact traces, which transmit the functions of the switch to the terminal contacts via a contact unit.

Because of these advantages, prefabrication of the switch mechanism of the steering column switch, together with the contact unit and the foot of the switch lever, is ensured in a relatively large number of pieces. Different grip pieces, insertable into the foot of the switch lever, each can be equipped with at least one arbitrarily designed switch. For example, a switch for interval functions of the windshield wiper is connected to the grip piece for a windshield wiper/washer switch. In addition or as an alternative, a switch to control a computer system is provided, in which the switch or switches cooperate with the contact traces integrated in the grip piece, and the electrical connection to the terminal contacts for the switch or switches is achieved by simple insertion of the grip piece into the foot over the contact unit.

In order to achieve rapid, permanent assembly, and also several degrees of freedom of the switch lever, the foot of the switch lever is preferably mounted as a swivel joint and provided with two opposite clip arms that engage in corresponding clip openings of the grip piece.

For simple swivel mounting of the switch lever and to achieve switching functions, the foot of the switch lever is expediently mounted to pivot in an opening of an arm of an L-shaped rotary switch element, where the rotary switch element is inserted into an arm of a Z-shaped support fixed to the housing. Arrangement of additional mounts with a switch lever therefore is unnecessary, since corresponding support sites are integrated in the rotary switch element.

The arm of the rotary switch element running parallel to the connector of the support is preferably provided with a terminating locating curved element that cooperates with a spring-loaded locating sleeve in the arm of the support facing the end of the rotary switch element. Thus, an initial position of the swivel-mounted switch lever is defined and a desired switching sensation is created during its operation. The arm of the support carrying the locating sleeve for the rotary switching element expediently comprises an additional spring-loaded locating sleeve that cooperates with a locating curve in the free end of the foot. Thus, the switch lever is held in a certain initial position. Pivoting of the switch lever from the initial position occurs against the spring force, to which the locating sleeve is exposed, so that a corresponding switch sensation is produced.

According to an advantageous modification of the invention, the arm of the support carrying the locating sleeves supports a sliding switch element, acted upon by the foot of the switch lever. The support therefore represents an essential component to accommodate the sliding switch element, as well as the rotary switch element, and forms a separate assembly with the connected switch element, which is simple to install and replace.

The switch contacts of the rotary switch element and the sliding switch element are expediently designed as contact springs and act on corresponding contact traces of the support that are connected to the terminal contacts. The contact springs are components of a punched grid inserted into the rotary switch element and the sliding switch element, which is simultaneously injection molded during production of the switch elements in the injection molding process, so that an additional assembly step can be eliminated. In order to avoid damage to the grip piece and the foot during assembly, the grip piece has a centering shoulder on the end inserted into the foot, which engages in a corresponding centering hole of the foot.

According to an advantageous embodiment of the concept of the invention, the contact traces of the grip piece are exposed regions of a punched grid integrated in the grip piece connected to the switch. Relatively costly wiring of the switch with the contact traces is therefore eliminated and a number of switching functions to be transmitted are possible by appropriate coding of the punched grid introduced to the grip piece.

In order to produce a cost-effective contact unit having relatively high functional safety and that ensures tolerance and movement compensation, the contact unit preferably has contact arms designed as leaf springs, where one end of each contact arm is connected to the corresponding contact trace of the punched grid of the grip piece and the other end of the contact arm is connected to a corresponding contact trace of the support. The contact arms of the contact unit that act on the contact traces of the support extend through a recess of the rotary switch element mounted in the support.

According to a modification of the invention, the contact unit has limiting arms on the side that extend essentially parallel to the contact arms. Each arm of the contact unit has a cylindrical shoulder on the end, where the opposite shoulders on one end of the contact unit engage in a corresponding recess of the rotary switch element and the shoulders on the other end of the contact unit engage in a corresponding recess of the foot. The contact unit therefore represents a compact assembly that can be fixed relatively simply between the rotary switch unit and the foot.

The recesses in the rotary switch element, in which the shoulders of the arm of the contact unit engage, are, advantageously, cylindrical holes. The recesses in the foot of the switch lever, into which the shoulders of the arm of the contact unit engage, are also elongated holes. In this way, a compensatory movement of the contact unit is guaranteed during the pivoting of the switch lever to act on the sliding switch element. The sliding of the contact arms of the contact unit on the corresponding contact traces of the grip piece and the contact traces of the support effects the self-cleaning of the support.

It is understood that the aforementioned features and those still to be explained can be used not only in the stated combination, but also in other combinations without departing from the scope of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now referring toFIG. 1, the steering column switch comprises a housing1that consists of a cover2and a support module3, and an individual switch6designed as a blinker switch4and a wiper/washer switch5, as well as a circuit board7. On the side facing the steering wheel (not shown), a transfer element8to control the functions of an airbag in cover2of housing1is inserted, which is connected to circuit board7. The cover2is provided with clip openings9on its periphery that engage with corresponding clip arms10of support module3. The support module3also contains a mount11for an ignition key and a fastening device12to attach the steering column switch to a jacket tube of a steering column of the vehicle.

The blinker switch4and the wiper/washer switch5are designed identically, and each consists essentially of a support13with terminal contacts14that engage in corresponding holes15of circuit board7, a rotary16and sliding switch element17and a swivel-mounted switch lever18. The switch lever18is designed in two parts and consists of a foot19and a grip piece20.

The support13is designed essentially Z-shaped and holds, in the arm21facing switch lever18, two superimposed, spring-loaded, locating sleeves22,23in the center, which are components of the locating elements24of the corresponding single switch6. For this purpose, a dome25is molded onto the arm21of support13, into which corresponding compression springs26are inserted that act on locating sleeves22,23. The arm21also has opposite grooves27to guide the sliding switch element17, as well as contact traces61.

The second arm28of support13, designed as a centering shoulder, is fixed in the support module3of housing1in a corresponding recess29. The connector30that connects arms21,28comprises a mounting hole31inserted into the centering shoulder in the region of arm28to support the rotary switch element16.

The essentially L-shaped rotary switch element16has switch contacts33assigned to the long arm32, which are designed as contact springs and cooperate with contract traces34in connector30of support13. The switch contacts33extend into a recess35of arm32and are provided on their free end with a V-shaped angle36, the point of which acts on the corresponding contact trace34. An additional recess37is provided in arm32of the rotary switch element16, parallel to the recess35for the switch contacts33. A locating curve60is introduced to the end of the arm32of rotary switch element16, which cooperates with the locating sleeve23of support13.

The short arm38of the rotary switch element16contains a bearing pin40, formed on the ends and on the opposite side, in which the end bearing pin40engages in a corresponding bearing hole in cover2of housing1and the opposite bearing pin40engages in the bearing hole31of support13. An opening39is formed in the short arm38, into which the foot19of switch lever18is inserted to pivot. For this purpose, foot19has axial pins41on the side that are mounted in corresponding holes42of arm38.

The foot19of switch lever18also contains a V-shaped, locating curve43on its free end facing arm21of support13, which cooperates with the upper locating sleeve22, as well as an operating shoulder44that limits the locating curve43that acts on the sliding switch element17. By cooperation of the locating sleeve22with the locating curve43of switch lever18, it is held in a center position, so that the sliding switch element17assumes an equivalent position. The switch contacts59that cooperate with the contact traces61in arm21of support13are connected to sliding switch element17.

A blind hole46with a rectangular cross section to accommodate the grip piece20is inserted in the longitudinal axis45of foot19of switch lever18. The side walls of the blind hole46are formed in areas by two opposite clip arms47that engage in corresponding clip openings48of grip piece20.

The grip piece20of the single switch6, designed as a blinker switch4, is provided with an additional switch49that serves as a push-button to control a computer system (not shown). For electrical contact transmission, a punched grid is integrated with the switch49in the grip piece20, having exposed contact traces50in the end region inserted into foot19. In the region of contact traces50, the foot19has a perforation58, penetrated by contact arms51of a contact unit52, in which the contact arms51, on the one hand, are connected to contact traces50of the punched grid of grip piece20and, on the other hand, pass through the recess37of the rotary switch element16, and are connected to corresponding contact traces53of support13.

Arms54are arranged parallel to contact arms51of the contact unit52for fastening of the contact unit on the foot19and on the rotary switch element16. For this purpose, each arm54has a cylindrical shoulder55on the end, in which the opposite shoulders55on one end of the contact unit52engage in corresponding holes56of the rotary switch element16, and the shoulders55on the other end of the contact unit52engage in corresponding elongated holes57of foot19. The required freedom of movement of the switch lever18is guaranteed by this mounting of the contact unit52with simultaneously ensured transfer of the functions of switch49.

After switch49is acted upon in any position of the switch lever18of the corresponding single switch6, the transfer of the switch signal occurs via punched grids integrated in the grip piece20and its exposed contact traces50to one end of the contact arms51of the contact unit52. The connection to the contact traces53of support13, and thus to the terminal contacts14coupled to the contact traces53, is produced via the contact arms51. The terminal contacts14again contact the circuit board7connected to the electrical system. To transmit complex switching functions or for assignment of switching functions to the corresponding single switch6, the punched grid of grip piece20can be coded, in which transmission occurs according to the coded signals.

LIST OF REFERENCE NUMBERS