Abstract:
A steering column assembly includes a rake adjustment mechanism, and is attached to a vehicle by a mounting bracket. A rake bracket is coupled to the mounting bracket. A column jacket is collapsible in response to an emergency event and is supported by the mounting bracket and the rake bracket, and is rotationally moveable with the rake bracket about a rake axis relative to the mounting bracket. An instrument cluster is coupled to the rake bracket for movement along with the rake bracket and the column jacket to prevent obstruction of the instrument cluster by a steering wheel upon re-positioning the steering wheel, while not restricting movement of the column jacket during collapse of the column jacket in response to the emergency event. A dynamic absorber interconnects the instrument cluster and the rake bracket to reduce vibration of the steering column assembly caused by additional weight of the instrument cluster.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. provisional patent application Ser. No. 60/816,174, filed on Jun. 23, 2006, the disclosure of which is herein incorporated by reference. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The subject invention generally relates to a steering column assembly for a vehicle. 
         [0004]    2. Description of the Related Art 
         [0005]    Vehicles typically include an instrument panel attached to a cross beam extending between a pair of front pillars. An instrument cluster is usually attached to the instrument panel, and is typically located above a steering column assembly. The instrument cluster includes instrumentation necessary for a driver to properly operate the vehicle, such as a speedometer, tachometer, fuel gauge, coolant temperature gauge, etc. The driver views the instrumentation by looking through and around a steering wheel attached to the steering column. 
         [0006]    Currently, many vehicles are equipped with adjustable steering column assemblies. The adjustable steering column assemblies may include rake adjustments for adjusting the height of the steering wheel, telescopic adjustments for adjusting the distance of the steering wheel from the driver, or may include both the rake adjustment and the telescopic adjustment. Accordingly, the steering wheel may be positioned in a manner that obstructs the view of the instrumentation of the instrument cluster. 
         [0007]    Mounting the instrument cluster on the steering column allows the instrument cluster to move with the steering column in both the rake and the telescoping adjustments. Accordingly, the instrument cluster maintains a fixed spatial relationship relative to the steering wheel, thereby ensuring the driver has a continuous unobstructed view of the instrument cluster regardless of the position of the steering wheel. U.S. Pat. No. 4,527,444 discloses a steering column assembly having both rake and telescopic adjustments with the instrument cluster permanently mounted to the steering column assembly. 
         [0008]    Modern vehicles incorporate a collapsible column jacket into the adjustable steering column assemblies, and further include energy absorption mechanisms. The energy absorption mechanisms absorb energy transmitted through the steering column as the steering column collapses along a longitudinal axis in response to an emergency event, such as a vehicular crash. 
         [0009]    However, the effectiveness of the energy absorption mechanism is reduced or eliminated by having the instrument cluster permanently mounted to the steering column assembly because the instrument cluster abuts against the instrument panel, thereby restricting movement of the collapsible column jacket. Additionally, the added weight of the instrument cluster onto the steering column assembly increases vibration of the steering column assembly felt by the driver, which is an undesirable effect. 
       SUMMARY OF THE INVENTION AND ADVANTAGES 
       [0010]    The subject invention discloses a steering column assembly for a vehicle. The steering column assembly comprises a mounting bracket for attaching the steering column assembly to the vehicle. A rake bracket is coupled to the mounting bracket, and is pivotable relative to the mounting bracket about a rake axis. The rake bracket extends from the mounting bracket along a longitudinal axis to a distal end. A column jacket is supported by the mounting bracket and detachable supported by the rake bracket. The column jacket is longitudinally moveable relative to the mounting bracket along the longitudinal axis in response to an emergency event. The column jacket is also pivotably moveable with the rake bracket relative to the mounting bracket about the rake axis. An instrument cluster is coupled to the distal end of the rake bracket. The instrument cluster is rotatably moveable with the rake bracket and the column jacket relative to the mounting bracket about the rake axis. 
         [0011]    Accordingly, the subject invention provides a steering column assembly in which the instrument cluster is coupled to the rake bracket. The instrument cluster moves with the rake bracket as the steering column assembly is adjusted about the rake axis to maintain an unobstructed view of the instrument cluster. The instrument cluster is not directly mounted onto the column jacket and therefore does not interfere with the collapse of the column jacket in response to the emergency event. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0013]      FIG. 1  is a perspective view of a steering column assembly; 
           [0014]      FIG. 2  is a side view of the steering column assembly shown in  FIG. 1 ; 
           [0015]      FIG. 3  is a schematic side view of the steering column assembly; 
           [0016]      FIG. 4  is a perspective view of a first alternative embodiment of the steering column assembly; 
           [0017]      FIG. 5  is a partial fragmentary perspective view of the first alternative embodiment of the steering column assembly shown in  FIG. 4 ; 
           [0018]      FIG. 6  is a perspective view of a second alternative embodiment of the steering column assembly; 
           [0019]      FIG. 7  is a partial perspective view of the second alternative embodiment of the steering column assembly shown in  FIG. 6 ; and 
           [0020]      FIG. 8  is fragmentary cross sectional perspective view of the second alternative embodiment of the steering column assembly shown in  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a steering column assembly is generally shown at  20 . The steering column assembly  20  is for a vehicle, and includes an energy absorption mechanism  22 . The energy absorption mechanism  22  absorbs energy transmitted through a column jacket  24  in response to an emergency event. The emergency event typically includes a vehicular impact. The energy absorption mechanism  22  reduces the amount of energy transmitted through the steering column assembly  20 , thereby reducing injury to a driver. There are several energy absorption mechanisms  22  known in the art capable of absorbing energy transmitted through the steering column assembly  20  that may be incorporated into the subject invention. Accordingly, the energy absorption mechanism  22  is not described in detail herein, and the scope of the claims should not be limited to the exact configuration or type of energy absorption mechanism  22  utilized. 
         [0022]    Referring to  FIGS. 1 and 2 , the steering column assembly  20  comprises a mounting bracket  26  for attachment to the vehicle. A rake bracket  28  is coupled to the mounting bracket  26  and also to the vehicle. The rake bracket  28  is pivotable relative to the mounting bracket  26  about a rake axis R, and extends from the mounting bracket  26  along a longitudinal axis L to a distal end  30 . The mounting bracket  26  includes a hinge  32  extending transverse to the longitudinal axis L, with the hinge  32  defining the rake axis R therethrough. 
         [0023]    The steering column assembly  20  further comprises a rake adjustment mechanism  34 . The rake adjustment mechanism  34  rotationally adjusts the column jacket  24  and the rake bracket  28  about the rake axis R relative to the mounting bracket  26 . The rake adjustment mechanism  34  also locks the column jacket  24  and the rake bracket  28  in position relative to the mounting bracket  26 . There are several known rake adjustment mechanisms  34  capable of adjusting and locking the rake position of the column jacket  24  and the rake bracket  28  that may be incorporated into the subject invention. Accordingly, the rake adjustment mechanism  34  is not described in detail herein, and the scope of the claims should not be limited to the exact configuration or type of rake adjustment mechanism  34  utilized. 
         [0024]    The column jacket  24  is supported by the mounting bracket  26  and detachably supported by the rake bracket  28 . The column jacket  24  is longitudinally moveable relative to the mounting bracket  26  along the longitudinal axis L in response to an emergency event, i.e., the column jacket  24  is collapsible in response to an emergency event. The column jacket  24  is also pivotably moveable with the rake bracket  28  relative to the mounting bracket  26  about the rake axis R. A steering wheel  36  is attached to an end of the column jacket  24  as is well known in the art. 
         [0025]    An instrument cluster  38  is coupled to the distal end  30  of the rake bracket  28 . The instrument cluster  38  is rotatably moveable with the rake bracket  28  and the column jacket  24  relative to the mounting bracket  26  about the rake axis R. The instrument cluster  38  includes an outer casing  40 , preferably manufactured from a plastic material. At least one gauge  42 , and preferably a plurality of gauges  42  are supported by the outer casing  40 . The gauges  42  typically include a speedometer, a tachometer, a fuel gauge, a temperature gauge, an oil pressure gauge, etc. It should be understood that the number and kind of gauges may vary depending upon the vehicular requirements, and that the scope of the claims are not limited to the number and kind of gauges. 
         [0026]    Referring also to  FIG. 3 , which is a schematic representation of the steering column assembly  20 , the steering column assembly  20  further comprises a dynamic absorber  44  interconnecting the instrument cluster  38  and the rake bracket  28 . The column jacket  24  and the attached steering wheel  36  vibrate at a resonance frequency as is well known in the art. The dynamic absorber  44  reduces the vibration transmitted to the instrument cluster  38  and also the vibration in the steering wheel  36 . Preferably, the dynamic absorber  44  includes a linear spring  48  having a pre-determined spring constant K z . The linear spring  48  supports the instrument cluster  38 , which includes a mass M z . The dynamic absorber  44  and the instrument cluster  38  are therefore cantilevered from the rake bracket  28 . Accordingly, the mass M z  of the instrument cluster  38  is coupled to the rake bracket  28  by the spring constant K z  and cooperate together to counteract the vibration in the column jacket  24  to reduce the overall vibration in the instrument cluster  38  and the steering wheel  36 . The linear spring  48  includes a cluster bracket  46 . The cluster bracket  46  includes a flange  50  interconnecting the cluster bracket  46  and the instrument cluster  38 . Accordingly, it should be understood that the outer casing  40  is attached to the flange  50  of the cluster bracket  46 . The instrument cluster  38  is fixedly mounted to the dynamic absorber  44 , and is therefore stationary relative to the mounting bracket  26  in response to the emergency event. It should be understood that the dynamic absorber  44  may include some other device capable of reducing vibration in the column jacket  24 . Accordingly, the scope of the claims should not be limited to the exact configuration of the dynamic absorber  44  described herein. 
         [0027]    As depicted in the embodiment shown in  FIGS. 1 and 2  with reference to the schematic representation shown in  FIG. 3 , the dynamic absorber  44  is integral with the rake bracket  28 . As such, the linear spring  48  is an extension of the rake bracket  28 . The pre-determined spring constant K z  is therefore dependent upon the geometric design of the dynamic absorber  44  and the material utilized to manufacture the dynamic absorber  44 . As is known in the art, the ability to reduce vibration is a factor of the spring constant K z  and the mass M z  of the object interconnected by the dynamic absorber  44 . Accordingly, the effect on vibration in the steering column assembly  20  by the dynamic absorber  44  is dependent upon the mass M z  of the instrument cluster  38  and the spring constant K z  of the dynamic absorber  44 . Knowing the mass of the instrument cluster  38  and the physical properties of the material utilized for the dynamic absorber  44 , one skilled in the art can customize the exact shape and configuration of the dynamic absorber  44  to best fit the specific design considerations and requirements. 
         [0028]    It should be understood that upon an emergency event, the column jacket  24  collapses along the longitudinal axis L. As the column jacket  24  collapses, the column jacket  24  detaches from the rake bracket  28  as is well known in the art. Accordingly, the instrument cluster  38  remains fixed in place, continuously attached to the rake bracket  28  and stationary relative to the mounting bracket  26  and the instrument panel, thereby permitting proper operation of the collapsible column jacket  24  and the energy absorption mechanism  22 . 
         [0029]    A first alternative embodiment of the steering column assembly is generally shown at  120  in  FIGS. 4 and 5 . A second alternative embodiment of the steering column assembly is generally shown at  220  in  FIGS. 6 through 8 . Features of the steering column assembly  20  shown in  FIGS. 1 and 2  that correspond to Features of the first alternative embodiment shown in  FIGS. 4 and 5  are represented by the same reference numeral preceded by the numeral “1”. Accordingly, the steering column assembly  20  shown in  FIGS. 1 and 2  is referenced in the first alternative embodiment as the steering column assembly  120 . Likewise, features of the steering column assembly  20  shown in  FIGS. 1 and 2  that correspond to features of the second alternative embodiment shown in  FIGS. 6 through 8  are represented by the same reference numeral preceded by the numeral “2”. Accordingly, the steering column assembly  20  shown in  FIGS. 1 and 2  is referenced in the second alternative embodiment as the steering column assembly  220 . 
         [0030]    Both the first and second alternative embodiments of the steering column assembly  120 ,  220  further comprise a telescoping mechanism  152 ,  252 . The telescoping mechanism  152 ,  252  adjusts the column jacket  124 ,  224  axially along the longitudinal axis L. Also, the telescoping mechanism  152 ,  252  locks the column jacket  124 ,  224  in position relative to the mounting bracket  126 ,  226 . There are several known telescoping mechanisms  152 ,  252  capable of adjusting and locking the telescoping position of the column jacket  124 ,  224  that may be incorporated into the subject invention. Accordingly, the telescoping mechanism  152 ,  252  is not described in detail herein and the scope of the claims should not be limited to the exact configuration or type of the telescoping mechanism  152 ,  252  utilized. 
         [0031]    Referring to the first alternative embodiment shown in  FIGS. 4 and 5 , the rake bracket  128  is axially adjustable along the longitudinal axis L with the column jacket  124 . The rake bracket  128  is in telescopic engagement with the mounting bracket  126  for axial movement along the longitudinal axis L relative to the mounting bracket  126 . The dynamic absorber  144  is fixedly mounted to the rake bracket  128 , and the instrument cluster  138  is fixedly mounted to the dynamic absorber  144 . It should be understood that the dynamic absorber  144  of the first alternative embodiment is identical to and operates in the same manner as the dynamic absorber  44  described in relation to  FIGS. 1 through 3 . 
         [0032]    The steering column assembly  120  of the first alternative embodiment allows the instrument cluster  138  to move with the column jacket  124  in both the rake direction and the telescoping direction during normal use. In response to the emergency event, the column jacket  124  collapses. As the column jacket  124  collapses, the column jacket  124  detaches from the rake bracket  128  and the instrument cluster  138 . The instrument cluster  138 , being fixedly mounted to the rake bracket  128  via the dynamic absorber  144 , remains stationary relative to the mounting bracket  126  and the instrument panel, thereby permitting proper operation of the collapsible column jacket  124  and the energy absorption mechanism  122 . 
         [0033]    Referring to the second alternative embodiment shown in  FIGS. 6 through 8 , the dynamic absorber  244  includes an arm  254  in telescopic engagement with the rake bracket  228 . The instrument cluster  238  is fixedly mounted to the dynamic absorber  244  and is axially moveable with the dynamic absorber  244  along the longitudinal axis L relative to the mounting bracket  226  in response to the emergency event. The dynamic absorber  244  defines a notch  256 , and a release capsule  258  is disposed in the notch  256 . A pin  260  extends through the column jacket  224 , the release capsule  258  and the rake bracket  228  for interconnecting the column jacket  224 , the dynamic absorber  244 , and the rake bracket  228 . It should be understood that the dynamic absorber  244  of the second alternative embodiment is identical to and operates in the same manner as the dynamic absorber  44  described in relation to  FIGS. 1 through 3 . 
         [0034]    The steering column assembly  220  of the second alternative embodiment allows the instrument cluster  238  to move with the column jacket  224  in both the rake direction and the telescoping direction during normal use. In response to the emergency event, the column jacket  224  collapses. As the column jacket  224  collapses, the dynamic absorber  244  and the column jacket  224  remain coupled together, and both the column jacket  224  and the dynamic absorber  244  detach from the rake bracket  228 . Accordingly, both the column jacket  224  and the dynamic absorber  244  collapse, and the instrument cluster  238  thereby moves relative to the mounting bracket  226  and the instrument panel during the emergency event. 
         [0035]    The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. As is now apparent to those skilled in the art, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, wherein reference numerals are merely for convenience and are not to be in any way limiting, the invention may be practiced otherwise than as specifically described.