Abstract:
An adjustable steering column assembly for a vehicle preferably has a bracket for rigid attachment to the vehicle with a first slot defining a longitudinal adjustment path of the assembly. A steering shaft is journaled to a jacket of the assembly for rotation about an axis. A shuttle attaches rigidly to the jacket and adjustably to the bracket for telescoping and tilt adjustment of the assembly. The shuttle has a second slot that defines a collapse path with said second slot preferably having a first portion restraining said steering shaft in a normal state and a second portion that allows said steering shaft to move through said collapse path when in a collapsed state. A pin extends through said first and second slots for coupling said shuttle to said bracket.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. Ser. No. 11/895,536 filed Aug. 24, 2007, which also claims priority to U.S. Provisional Patent Application Ser. No. 60/905,715 filed Mar. 8, 2007, the contents each of which are incorporated herein by reference thereto. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This application relates generally to an adjustable steering column assembly for a vehicle, and more particularly to an adjustable steering column that longitudinally collapses during a vehicle crash for the absorption of kinetic energy. 
       BACKGROUND ART 
       [0003]    Automotive steering columns are typically equipped with kinetic energy absorption devices to reduce injury of the vehicle operator in event of a collision during which the operator impacts the steering wheel, causing the column to collapse. 
         [0004]    Such energy absorbing steering columns generally include a jacket that translates linearly through a collapse stroke during a collision. A force generated by the driver from an impact with the steering wheel initiates the collapse stroke. The steering wheel jacket moves against a resisting force that may be produced by an energy absorber designed to convert a portion of the driver&#39;s kinetic energy into work. The resisting force may be generated utilizing systems currently known in the art, including the plastic deformation of a metal element that is a part of an energy absorbing device. 
         [0005]    Typically, the column assembly is secured to the vehicle structural member that may be part of its instrument panel or a cross-car beam. As is well-known in the art, the column jacket is provided with a mounting bracket having capsules fitted thereto through which bolts extend, the capsules being dislodged from the column mounting bracket as the column strokes during collapse, thereby permitting forward translation of the column relative to the vehicle structural member while the capsules remain secured to the vehicle structural member, the forward translation of the column being against the resisting force of the energy absorbing device. 
         [0006]    The mounting bracket and its capsules also provide the means for vertically supporting the end of the column nearest the hand wheel, and upon release of the capsules from the mounting bracket during column collapse, the column assembly and the steering wheel, now no longer vertically supported through the capsules&#39; being secured to the vehicle&#39;s structural member, may drop into the driver&#39;s lap and impede his extrication from the vehicle after the collision. It has been found desirable, and becoming increasingly required, that the steering column remain upwardly supported away from the driver after collapse of the column during crash. Thus, there is a need for a collapsible steering column assembly that provides such a feature, preferably at low cost and without great complexity. It is further desirable that such a column assembly also be provided with driver-adjustable rake and/or telescope positioning features often found in prior vehicles. 
       SUMMARY OF THE INVENTION 
       [0007]    In an embodiment, an adjustable steering column assembly for a vehicle comprises a bracket for rigid attachment to the vehicle and having slots defining a longitudinal path. A telescoping steering shaft is rotatable about an axis. A jacket is journaled to said shaft and a shuttle is attached rigidly to said jacket and has mounting slots therein. A pin extends though said bracket slots and said mounting slots to connect said shuttle to said bracket, wherein said bracket slots or said mounting slots have a first portion restraining said pin, said shuttle and said jacket in a normal state and a second portion allowing said pin, said shuttle and said jacket to move through a collapse path when in a collapse state. 
         [0008]    In another embodiment, an adjustable steering column assembly of a vehicle comprises a bracket for rigid attachment to the vehicle and having a slot defining a longitudinal path. A telescoping steering shaft is rotatable about an axis. A telescoping jacket is journaled to said shaft and a shuttle is attached rigidly to said telescoping jacket and has a rake adjustment path defined by substantially vertical slots therein. A rake rod extends though said bracket slot and said substantially vertical slots to moveably connect said shuttle to said bracket for rake adjusting said telescoping steering shaft and said telescoping jacket, wherein said bracket slot has a first portion restraining said pin, shuttle and said telescoping jacket in a normal state and a second portion allowing said pin, said shuttle and said telescoping jacket to move through a collapse path when in a collapse state. 
         [0009]    Objects, features and advantages of the present invention include an adjustable steering column assembly that remains upwardly supported and away from the driver after a collision. Other advantages include an assembly that is both longitudinally and rake adjustable, and a robust and relatively simple design that is economical to manufacture and requires little or not maintenance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    These and other objects, features and advantages of this invention will be apparent from the following detailed description, appended claims, and accompanying drawings in which: 
           [0011]      FIG. 1  is a perspective view of an adjustable steering column assembly embodying the present invention; 
           [0012]      FIG. 2  is an exploded perspective view of the adjustable steering column assembly; 
           [0013]      FIG. 3  is a side view of the adjustable steering column assembly in a retracted position; 
           [0014]      FIG. 4  is a side view of the adjustable steering column assembly in an extended position; 
           [0015]      FIG. 5  is a cross section of the adjustable steering column assembly of  FIG. 1 ; 
           [0016]      FIG. 6  is a side view of the adjustable steering column assembly is a collapsed state; 
           [0017]      FIG. 7  is a side view of a shuttle of the adjustable steering column assembly; 
           [0018]      FIG. 8  is a side view of a bracket of the adjustable steering column assembly; and 
           [0019]      FIG. 9  is an exploded perspective view of a second embodiment of an adjustable steering column assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    Referring now to  FIGS. 1 and 2  of the drawings, an adjustable steering column assembly  20  for a vehicle has a steering shaft  22  that projects rearward with respect to the vehicle and along a rotation axis  24  to a distal end  26  that attaches to a steering wheel (not shown). The steering shaft  22  is preferably journaled to and rotates within a tubular housing or jacket  28  engaged rigidly to or generally having a compression bracket or shuttle  32 . The shuttle  32  is supported by a bracket  30  of the assembly  20  that engages rigidly to a chassis of the vehicle via a plurality of fasteners (not shown) that project preferably upward from the bracket  30  to engage the chassis. 
         [0021]    The jacket  28  and co-extending shaft  22  are preferably constructed and arranged to extend and retract longitudinally as a single unit and with respect to the bracket  30  between a retracted position  34  (see  FIG. 3 ) and an extended position  36  (see  FIG. 4 ). When extending, the jacket  28  and shaft  22  move in a linear rearward direction with respect to the vehicle, and when retracting, the jacket  28  and shaft  22  move in a forward direction and generally into the bracket  30 . 
         [0022]    This forward and rearward movement, however, is not necessarily parallel to rotation axis  24  of steering shaft  22  because the jacket  28  and shaft  22  are preferably constructed and arranged to tilt as a single unit between a rake or tilt down state (not shown) and a rake or tilt up state (as shown in  FIGS. 3 and 4 ). This tilt adjustment moves the distal end  26  of the steering shaft  22  in an arcuate and substantially vertical direction (see arrow  38  in  FIG. 3 ). To accommodate drivers of small stature, the jacket  28  is generally extended near the extended position  36  and tilt down state. To comfortably accommodate drivers of larger stature, the jacket  28  is generally retracted to near the retracted position  34  and the tilt up state. 
         [0023]    In addition to the steering shaft  22 , the jacket  28 , the bracket  30  and the shuttle  32 , the steering column  20  also has a locking device  40  that is supported by and interfaces between the shuttle  32  and bracket  30  for column adjustment. Various bushings  42  of the assembly  20  rotationally support of the steering shaft  28  to the jacket  28  and a steering lock mechanism  44  is integrated between the shaft  22  and an ignition (not shown) to prevent shaft rotation when the vehicle ignition is off A kinetic energy absorbing device or strap  46  of the assembly  20  absorbs kinetic energy produced when a driver strikes the steering wheel during vehicle collisions, and an adjustable intermediate shaft  48  of assembly  20  extends between forward and rearward universal joints  50 ,  52 . The forward joint  50  connects to a front steering system or steering gear assembly of the vehicle (not shown) and the rearward joint  52  connects to the steering shaft  22 . 
         [0024]    Referring to  FIGS. 1-2 ,  5  and  8 , the bracket  30  has a substantially horizontal base plate  54  preferably secured rigidly to the vehicle chassis beneath a dash structure. Two vertical panels  56 ,  58  of the bracket  30  project downward from the base plate  54  to adjustably connect with the shuttle  32 . The panels  56 ,  58  are each elongated horizontally, are substantially parallel to one another, and carry respective slots  60 ,  62  that also extend horizontally. Preferably and as illustrated, the mounting bracket  30  is a stamping, however, alternative versions of this bracket may be a casting. 
         [0025]    Referring to  FIGS. 1-2 ,  5  and  7 , the shuttle  32  is generally U-shaped and rigidly connects to the jacket  28 . Two substantially vertical walls  64 ,  66  of the shuttle  32  project substantially upward and generally above the jacket  28  for adjustable connection to the respective panels  56 ,  58  of the bracket  30 . Substantially horizontal slots  68 ,  70  and substantially vertical and arcuate slots  72 ,  74  are in respective walls  64 ,  66 , so that slots  68 ,  70  generally co-extend with respective slots  60 ,  62  in the bracket  30  and slots  72 ,  74  cross over respective slots  60 ,  62  in the bracket  30 . Preferably, the arcuate slots  72 ,  74  are parallel to one another and spaced rearward from the respective slots  68 ,  70 . 
         [0026]    When the shuttle  32  is assembled to the bracket  30 , a guide pin  76  extends through slots  68 ,  70  of the shuttle  32  and through slots  60 ,  62  of the bracket  30 . Preferably, the pin  76  is a threaded bolt having an enlarged head at one end and a threaded nut  78  at an opposite end. Similarly, a rake rod  80  projects through arcuate slots  72 ,  74  of the shuttle  32  and slots  60 ,  62  of the bracket  30 . The rod  80  is preferably a threaded bolt having an enlarged head at one end and a threaded nut  82  at an opposite end. The rod  80  is generally part of the locking device  40  that further has a handle  84  that interfaces with the bolt  80  axially between the nut  82  and the wall  64  of the shuttle  32 . When the handle  84  is actuated or rotated about rod  80 , the walls  64 ,  66  release and clamp against the bracket  30  for respective adjustment of the column assembly  20  and locking established adjustment in place. 
         [0027]    Referring to  FIGS. 1-4  and  6 , the intermediate shaft  48  adjusts axially (i.e. telescopically) for longitudinal adjustment of the column assembly from the retracted position  34  to the extended position  36  when in a normal state or configuration, and also adjusts longitudinally to a collapsed position  88  when the assembly is in a collapsed state  90  (see  FIG. 6 ). To achieve axial adjustment, the intermediate shaft  48  has an outer sleeve  92  that attaches to the forward U-joint  50  at a forward end  94 , and an inner sleeve  96  that attaches to the rearward U-joint  52  at a rearward end  98 . The inner sleeve  96  is slidably disposed inside the outer sleeve  92 , and are rotatably fixed to one another preferably through splines in a manner well-understood by those of ordinary skill in the art. 
         [0028]    During normal operation of the assembly (i.e. normal state  86 ), the guide pin  76  is fixed releasably in forward end portions  100  of both horizontal slots  68 ,  70  of the compression shuttle  32  (see  FIGS. 1 and 7 ). When so fixed, the guide pin  76  is positioned furthest away from the rake rod  80  and generally by a distance that is equal to a radius of curvature  102  of the arcuate slots  72 ,  74  (i.e. from a centerline  104  of pin  76  to a mean radius of curvature of the arcuate slots). The remaining portion or rearward end portions  106  of straight slots  68 ,  70  project rearward from respective portions  100  by a distance that is generally equal to a collapse stroke of the assembly  20  during a collision. During this collapse stroke kinetic energy is absorbed as the pin  76  travels through portion  106  of slots  68 ,  70 . To absorb kinetic energy, the walls  64 ,  66  of shuttle  32  are plastically deformed. Such deformation occurs because a width  108  of portion  106  is less than a diameter of the pin  76 . In contrast, a width  110  of portion  100  of slots  68 ,  70  is lightly greater than the pin diameter for pivoting of the shuttle  32  and jacket  28  about centerline  104  during rake adjustment of the steering column. 
         [0029]    During telescopic adjustment of the steering column assembly  20 , the intermediate shaft  48  extends and/or retracts telescopically and the shuttle  32  moves with respect to bracket  30 . During this movement, the pin  76  and rod  80  maintain a constant distance (i.e. the radius of curvature  102 ) from each other, and move together along bracket slots  60 ,  62 . During raking adjustment of the column assembly  20 , in which mounting bracket  30  and compression shuttle  32  are moved angularly relative to each other, rake rod  80  moves along arcuate slots  72 ,  74  with compression shuttle  32  pivoting relative to mounting bracket  30  and about the centerline  104  of guide pin  76 . 
         [0030]    Referring to FIGS.  2  and  7 - 8 , the energy absorbing system or U-shaped strap  46  of assembly  20  will further absorb kinetic energy during collapse by resistively permitting motion between the vehicle structural member and the steering shaft  22 . The strap  46  may be an elongate metal element having a first end secured to mounting bracket  30  with rivet  112 , and a free second end that lies along the outer surface of jacket  28 . Between its first and second ends, strap  46  is disposed about rake rod  80 . During initial column collapse, any inward travel available to normal telescopic movement of the column is taken up as the above-mentioned frictional engagement between compression shuttle  32  and mounting bracket  30  is overcome. Beyond the point where normal inward telescopic column travel is reached (i.e. guide pin  76  rest upon a rearward stop  120  carried by panels  56 ,  58  of bracket  30  generally defining ends of slots  60 ,  62 ), at which point a bushing  114  about rake rod  80  becomes seated in the U-shaped bend of strap  46  and/or guide pin  76  reaches the rearward end of slots  68 ,  70  plastic deformation of the strap  46  occurs as column collapse continues. During this portion of column collapse, as strap  46  becomes unwrapped from about rake rod bushing  114 , guide pin  76  is dislodged from its releasably fixed position within substantially horizontal slots  68 ,  70  and slides along slots  68 ,  70  toward rake rod  80  (as shown through comparison of  FIGS. 3 and 6 ). Collapse of the column assembly  20  as described above also causes continued telescopic collapse of intermediate shaft  48 . 
         [0031]    During and subsequent to assembly  20  collapse as a result of a collision, the column assembly and hand wheel remains upwardly supported away from the driver, thereby facilitating his extrication from the vehicle after the collision. At all times, mounting bracket  30  remains fixed to the vehicle structural member (not shown), and compression shuttle  32  remains connected to mounting bracket  30 , as does jacket  28 , shaft  22  and the hand wheel. Maintained frictional engagement between compression shuttle  32  and mounting bracket  30  subsequent to collapse would maintain the column&#39;s set rake position, thereby upwardly supporting the column away from the driver&#39;s lap. 
         [0032]    Further, during collapse, as guide pin  76  moves from its releasably fixed position along substantially horizontal slots  68 ,  70  toward rake rod  80 , it is moved to distances smaller than the radii of curvature  102  of slots  72 ,  74 , thereby inhibiting pivoting movement of the compression shuttle  32  about the centerline  104  of guide pin  76  through movement of the compression shuttle relative to rake rod  80 ; the curved sides of arcuate slots  72 ,  74  coming into interfering engagement with the rake rod  80 . Thus downward movement of the column from its set rake position through the possible disengagement of locking device  40  during the collision would also be inhibited by the changed distance between guide pin  76  and rake rod  80  resulting from column collapse, thereby upwardly supporting the column away from the driver&#39;s lap. 
         [0033]    Referring to  FIG. 9 , a second embodiment of a steering column assembly  220  is illustrated wherein like elements to the first embodiment are identified with like element numbers except with the addition of two hundred. Unlike assembly  20 , assembly  220  has a telescoping jacket  228  that generally/functionally replaces the telescoping intermediate shaft  48  of the first embodiment. Therefore, the jacket  228  has an outer sleeve  120  and an inner sleeve  122  that move axially with respect to one another. Similarly, a telescoping steering shaft  222 , disposed in the jacket  228  has an elongated inner portion  124  and an elongated outer portion  126  that move axially with respect to one another and in unison with the telescoping movement of the jacket  228 . A coiled or compression spring  128  is compressed between a support structure  130  of the inner sleeve  122  and the underside of the bracket  230  to assist in tilt adjustment. 
         [0034]    In operation, the inner sleeve  122  of the jacket  228  remains longitudinally stationary with respect to the bracket  230  while allowing the jacket  228  to adjustably tilt about the pivot pin  276  that extends through the bracket  230  and the support structure  128  of the inner sleeve  122 . The shuttle  232  is engaged rigidly to the outer sleeve  120  of the jacket  228  and a rake rod  280  extends through substantially vertical slots  272 , 274  in the shuttle  232  and substantially horizontal slots  260  in the bracket  230 . The assembly  220  does not have the shuttle slots  68 , 70  of the first embodiment. Instead, the slots  260  are contoured for plastic deformation of the bracket  230  by the rod  280  during a collision. 
         [0035]    While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all the possible equivalent forms or ramification of the invention. It is understood that terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention.