Abstract:
A self-locking ignition switch for engagement with a lock housing driver of a motor vehicle having a key activated ignition system. The ignition switch includes a switch mechanism that is moveable between multiple key positions. The switch mechanism is enclosed within a casing, and the casing including a collar extending from a side wall of the casing and terminating at a distal end. The collar further has portions defining an interference and portions defining a side opening extending from the distal end toward the side wall of the casing. A slide member positioned within the collar and biased by a biasing member so as to engage the interference. Engagement between the interference and the slide member forms a lockout that fixes the switch mechanism in an installation configuration and prevents movement of the portions of the switch mechanism between the multiple key positions prior to installation.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention generally relates to an ignition switch for a motor vehicle. More specifically, the invention relates to an ignition switch that is self-locking in an installation configuration. 
         [0003]    2. Description of Related Art 
         [0004]    Currently, motor vehicle ignition switches are designed such that the ignition switch can be rotated between several key positions, which include OFF, ACC, RUN, and START. To define these positions, the ignition system utilizes a detent mechanism wherein a different detent position holds the ignition switch in each of the key positions. In addition to providing a tactile indication that the ignition switch has been moved to a different key position, the detent mechanisms are used to maintain the ignition switch in a known position that will allow it to be installed in the motor vehicle and engage with the lock driver of the assembly. 
         [0005]    Because the detent mechanism is utilized in establishing the installation configuration for the ignition switch, if one desired to remove the detent mechanism from the ignition switch in order to simplify construction, one would encounter the problem where the ignition switch is not maintained in a known configuration or one that would allow it to be installed to ensure engagement with the lock driver. 
         [0006]    In view of the above, it is apparent that there exists a need for a means by which an ignition switch can be fixed in an installation configuration while not requiring that the ignition switch does not include or does not utilize detent mechanisms associated with the various key positions to maintain the ignition switch in its installation configuration. 
         [0007]    In addition to the above, various regulations around the world require that the ignition switch be constructed such that it cannot be removed from the lock housing in the OFF key position. As such, a potential thief cannot remove the ignition switch simply by releasing the fasten feature. 
       SUMMARY 
       [0008]    In satisfying the above need, as well as overcoming the enumerated drawbacks and other limitations of the related art, in one aspect the present invention provides a self-locking ignition switch for engagement with a lock housing driver of a motor vehicle having a key activated ignition system. The ignition switch comprises a switch mechanism that is moveable between multiple key positions. The switch mechanism is enclosed within a casing, and the casing including a collar extending from a side wall of the casing and terminating at a distal end. The collar further has portions defining an interference and portions defining a side opening extending from the distal end toward the side wall of the casing. The switch mechanism further includes a slide member positioned within the collar, the slide member biased by a biasing member so as to engage the interference. Whereby engagement between the interference and the slide member forms a lockout that fixes the switch mechanism in an installation configuration and prevents movement of the portions of the switch mechanism between the multiple key positions prior to installation of the ignition switch. 
         [0009]    In another aspect, the invention provides an ignition switch for engagement with a lock housing driver of a motor vehicle having a key activated ignition system wherein the ignition switch includes a switch mechanism having portions moveable between multiple key positions. The switch mechanism is enclosed within a casing, and the casing including a collar extending from a side wall of the casing and terminating at a distal end. The collar further has portions defining a side opening extending from the distal end toward the side wall of the casing. The switch mechanism further includes a moveable wall member, positioned within the collar, which can be moved between a first position and a second position. In the first position, a central region within the collar is accessible through the side opening of the collar. In the second position, the side opening is obstructed by the wall member such that the central region is not accessible through the side opening. 
         [0010]    Further objects, features and advantages of this invention will become readily apparent to persons skilled in the art after a review of the following description, with reference to the drawings and claims that are appended to and form a part of this specification. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an exploded perspective view of an ignition switch assembly embodying the principles of the present invention; 
           [0012]      FIG. 2  is a view similar to  FIG. 1  illustrating the ignition switch assembly, with portions broken away to see the engagement of various internal components thereof; 
           [0013]      FIG. 3  is a partial perspective view of the engagement of the internal components seen in  FIG. 2 ; 
           [0014]      FIG. 4  is an enlarged perspective view of the collar and associated components of the ignition switch in an installation configuration; and 
           [0015]      FIG. 5  is an enlarged perspective view of the collar and associated components of the ignition switch in an installed orientation whereby the ignition switch is prohibited from being removed from the lock housing. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Referring now to the drawings, an ignition assembly embodying the principles of the present invention is generally illustrated therein and designated at  10 . As its primary components, the ignition assembly  10  includes an ignition switch  12 , a lock housing  14 , a lock cylinder (not shown) and a lock driver  16 , all of which are typically incorporated into the steering column assembly (not shown) of a motor vehicle. As seen in  FIGS. 1 and 2  the ignition assembly  10  further incorporates a saddle  18  so as to secure the ignition assembly  10  to the steering column (not shown) of the steering column assembly. The lock driver  16  is engaged with the ignition switch  12  such that when a key is inserted into the lock cylinder and turned, the cylinder causes the lock driver  16  to correspondingly turn, which further manipulates the ignition switch  12  into one of its OFF, ACC, RUN and START key positions. 
         [0017]    The lock housing  14  is itself divided into two parts, namely a driver housing  20  and an ignition switch housing  22 . These housings respectively contain the lock driver  16  and the ignition switch  12  therein. 
         [0018]    To position the lock driver  16  within the driver housing  20 , the driver housing  20  is formed by two half shells  24 ,  26  that define a cavity into which the lock driver  16  is seated. The half shells  24 ,  26  can be secured together by various conventional means including, but not limited, to an internally threaded boss on one of the half shells and externally threaded bolt extended through a correspondingly positioned bolt opening on the other of the half shells. 
         [0019]    The ignition switch  12  is received into a cavity defined within the ignition switch housing  22 . To receive the ignition switch  12  in that cavity, the ignition switch housing  22  is provided with an opening  32  in one wall thereof, and the ignition switch  12  is inserted into the cavity through the opening. In the view presented by  FIGS. 1 and 2 , this opening  32  is provided in the lower end or bottom wall of the ignition switch housing  22 . 
         [0020]    Although the lock driver  16  is received within the driver housing  20 , a distal or driver end  28  of the lock driver  16  extends a predetermined distance into the cavity of the ignition housing  22 . When the ignition switch  12  is installed in the ignition switch housing  22 , this driver end  28  engages a portion of the ignition switch  12 , as is further described below, to operate the switch  12 . 
         [0021]    As suggested above, the ignition switch  12  is the mechanism which specifically determines the operating state of the motor vehicle. As such, the ignition switch is constructed so as to define various key positions, which include OFF, ACC, RUN and START. When a key is inserted into the ignition assembly  10  and turned to the START position, various internal components of the ignition switch  12  are caused to rotate, thereby initiating communication with the electronic control module (ECM) of the vehicle, which in turn communicates with other vehicle components, such as the starter, to start the engine of the vehicle. Once the vehicle has started, the operator releases the key back to the RUN position. With the switch  12  in this position, the ECM causes the starter to disengage and the engine to continue the RUN. When turned to the OFF position, the ignition switch sends a signal to the ECM to shut the engine down. In the ACC position, the ignition switch  12  causes the ECM to allow various systems of the vehicle, such as the entertainment system, to operate without the running of the vehicle&#39;s engine. 
         [0022]    As previously mentioned, the ignition switch  12  is inserted into the ignition switch housing  22  by passing the ignition switch  12  through the opening  32 , generally in the direction of arrows  30  seen in  FIG. 1 . The ignition switch  12  is inserted into the cavity until it engages with the driving end  28  of the lock driver  16 . To facilitate positioning of the ignition switch  12  within the housing  22 , longitudinal ribs (an alignment or guiding feature)  36  are formed on the exterior casing  34  of the ignition switch  12 . The ribs  36 , which are seen in  FIG. 1 , are designed to engage with a corresponding longitudinal groove formed in an internal sidewall of the ignition switch housing  22 . 
         [0023]    The lock driver  16  extends into the ignition switch housing  22  along an axis that is perpendicular to the installation direction of the ignition switch  12  and to an extent that would interfere with installation of the ignition switch  12 . For this reason, the ignition switch  12  includes features that allow maintain the ignition switch in orientation permitting full installation of the ignition switch  12  and engagement with the driving end  28  of the lock driver  16 . 
         [0024]    As seen in  FIG. 3 , the driving end  28  of the lock driver  16  is shown engaged with the ignition switch  12  (in this figure, the lock housing  14  is omitted in the interest of clarity). In order to engage with the driving end  28  of the lock driver  16 , the ignition switch  12  is provided with a collar  38  that extends from a wall  40  of the switch case  34  that faces in the direction of the lock driver  16 . As such, the collar  38  extends axially in the direction of the lock driver  16 . 
         [0025]    As mentioned previously, during installation, the ignition switch  12  is inserted in a direction that is perpendicular to the longitudinal axis of the lock driver  16 . To permit the driving end  28  to be received into the collar  38 , a side opening  42  (that is open in the direction of insertion  30 ) is defined in the collar  38 . The side opening  42  extends circumferentially around or about the collar  38  less than 180°, and more preferably less than 90°, of the circumferential extent of the collar  38 . Accordingly, during installation, the rib  36  positions the ignition switch  12  such that the driving end  28  of the lock driver  16  passes through the side opening  42  and into collar  38  until fully seated therein, which occurs simultaneously with full insertion of the ignition switch  12  in the ignition switch housing  22 . To further facilitate engagement of the driving end  28  within the collar  38 , the driving end  28  is formed with a pair of opposed flat lands or surfaces  44 . The width between the lands  44  is sized to be less than the effective width of the side opening  42 . 
         [0026]    For ease of installation, it is preferable that the ignition switch  12  is locked in a preset, installation position. This not only facilitates installation, but also provides a known initial key position for the ignition switch  12  relative to the lock driver  16 . As noted above, detent systems were previously used to define the key positions of the ignition system and to hold the ignition switch in a specific orientation prior to and during installation. However, the ignition switch  12  utilized in the present invention does not include detent mechanisms to define the key positions. Accordingly, a novel way of fixing the installation orientation of the ignition switch  12  had to be developed. 
         [0027]    The present invention fixes the installation orientation of the ignition switch  12  through a modification of the key buzzer switch that is conventionally found in ignition assemblies. The key buzzer switch is a switch that activates a buzzer (an audible signal) whenever the ignition switch is in the OFF position and the vehicle&#39;s key is located within the ignition assembly; the purpose of which is to try and prevent the locking of the key in the vehicle when the operator leaves the vehicle. 
         [0028]    The key buzzer switch can take on a variety of constructions and the details of such constructions are well known in the industry and generally specific to the particular application. However, a common component is a slide member of the ignition switch that depressed when the key is located in the ignition assembly. When the slide member is depressed and the ignition switch is in the OFF position, the key buzzer switch is in a closed switch position and the buzzer is activated. By removing the key from the ignition assembly, the slide member is biased into an open switch position and the buzzer is not activated. 
         [0029]    Referring now to the enlarged view of the collar  38  in  FIG. 4 , as seen therein the collar  38  terminates at its outward or distal end  46  in a lip or flange  48 . The flange  48  extends radially inward from the distal end  46  to form an internal overhang. Within the collar  38 , and beneath the overhang of the flange  48 , are two fingers or portions  50  of a slide member  51  of a key buzzer switch  52  (the remaining details and components of the key buzzer switch  12  are being omitted in that they are well known). The slide member  51  is biased by a spring or other biasing means such that the fingers  50  are urged into contact with the flange  48 , which is generally in the direction of arrow  54 . 
         [0030]    Formed in the flange  48 , at opposed locations, are interferences or recesses  56 . The recesses  56  are sized to receive and engage the ends of the fingers  50  of the slide member  51 . Being biased in the direction of arrow  54 , the engagement between the recesses  56  and the ends of the fingers  50  operates to self-lock the ignition switch  12  in a fixed rotary position, which happens to be the installation configuration of the ignition switch  12 . This rotary position may also correspond to one of the key positions, such as the ON position. 
         [0031]    As seen in  FIG. 4 , when the ends of the fingers  50  are engaged with the recesses  56 , the constitution of the associated components of the collar define an open central region  58 , corresponding in width to the side opening  42  and for receiving the driving end  28  of the lock driver  16 . When the lock driver is received in the central region  58 , insertion of a key will cause advancement of a plunger (not shown) in the lock driver  16 , and the plunger will depress the slide member  51  in an opposite direction to arrow  54 , causing the end of the fingers  50  to withdrawal or retract from the recesses  56  and allow the ignition switch  12  to be rotated to any of key positions. 
         [0032]    By initially configuring the ignition switch  12  such that the ends of the fingers  50  are located in the recesses  56 , the ignition switch  12  is locked in installation configuration ensuring that the driving end  28  of the lock driver  16  will be received therein during installation and that the initial position of the ignition switch  12  will be known after installation. 
         [0033]    Once installed, advancement of the plunger of the lock driver  16  disengages the fingers  50  from the recesses  56  and allows the ignition switch  12  to be rotated out of the installation configuration and into the OFF position. Various governmental regulations require that the construction of an ignition assembly be such that the ignition switch cannot be removed from the switch housing when in the OFF position. To achieve this with the prevent invention, an internal wall  60  provided as part of the associated components within the collar  38 . 
         [0034]    As seen in  FIG. 5 , when rotated into the OFF position, the internal wall  60  is moved into a position where it blocks and obstructs the side opening  42  in the collar  38 . While  FIG. 5  looks very similar to  FIG. 4 , in  FIG. 5  the various components within the collar  38  have been rotated 180° from their position in  FIG. 4 . Thus, in  FIG. 4 , the internal wall  60  is not visible, but is located opposite of the side opening  42  and under the flange  48 . When moved to the position seen in  FIG. 5 , the internal wall  60  encloses and captures the driving end  28  of the lock driver  16  within the central region  58  of the collar  38 , thereby preventing the ignition switch  12  from being disengaged from the lock driver  16  and removed from the lock housing  14 . 
         [0035]    The internal wall  60  is formed integrally or unitarily with other wall portions  62  also provided within the collar  38 . These other wall portions  62  also operate to form guides between which the slide members  51  are retained and directed. While the wall portion  60  is shown as being moved  180 ° from its position in  FIG. 4  so as to obstruct the side opening  42 , the amount of rotation can be less than 180° so long as a portion of the other wall portions  62  obstructs the side opening  42  and prevents withdrawal of the driving end  28  of the lock driver  16  through the side opening  42 . 
         [0036]    As a person skilled in the art will readily appreciate, the above description is meant as an illustration of implementation of the principles this invention. This description is not intended to limit the scope or application of this invention in that the invention is susceptible to modification, variation and change, without departing from spirit of this invention, as defined in the following claims.