Collapsible steering column assembly

Abstract

A collapsing steering column assembly for an automotive vehicle, comprising an inner column tube, a steering shaft, a tilt bracket, and a steering wheel adjustment subassembly. During a secondary impact, at least a portion of the steering wheel adjustment subassembly is adapted to detach relative to the tilt bracket by way of at least one breakaway structure and translate (e.g., at least partially longitudinally) during the impact, such as a secondary impact, for moving away from a vehicle operator.

What is claimed is: 
     
         1 ) A collapsing steering column assembly comprising:
 a) a steering shaft support structure;   b) a steering shaft that is supported for rotation at least in part by the steering shaft support structure and having a longitudinal axis;   c) a bracket for at least partially carrying the steering shaft support structure and attaching the assembly within a vehicle;   d) a securing member for fixing a secure engagement position of the steering shaft support structure relative to the bracket; and   e) a breakaway structure associated with the bracket, the securing member, or both;
 wherein the securing member is configured relative to the breakaway structure in a manner such that in an event of an impact exceeding a threshold load, at least a portion of the securing member breaks away from the secure engagement position by way of the breakaway structure and allows at least a portion of the steering shaft support structure, at least a portion of the securing member that breaks away, or both to translate forward. 
   
     
     
         2 ) The assembly of  claim 1 , wherein the steering shaft support structure includes an inner column tube and a column housing, wherein the inner column tube is configured for telescoping insertion within the column housing. 
     
     
         3 ) The assembly of  claim 2 , wherein the securing member applies a clamping force for securing the column housing to the inner column tube by way of a lever. 
     
     
         4 ) The assembly of  claim 1 , wherein the assembly includes a manually operated steering wheel adjustment subassembly adapted for:
 a) selectively adjusting the steering shaft in a fore or aft direction generally along the longitudinal axis;   b) selectively raising or lowering the steering shaft; or   c) both a) and b);   wherein the steering wheel adjustment subassembly includes a lever for manually actuating the steering wheel adjustment subassembly.   
     
     
         5 ) The assembly of  claim 1 , wherein the bracket includes a pair of generally opposing downwardly oriented walls that flank at least a portion of the steering shaft support structure; and wherein the breakaway structure includes at least one breakaway insert that is operatively attached with at least one of the downwardly oriented walls in a normal operating position. 
     
     
         6 ) The assembly of  claim 5 , wherein one or both of the downwardly oriented walls includes a forward facing cut-out to receive the at least one breakaway insert, and wherein the at least one breakaway insert has a length and includes a tapered portion that tapers from a forward portion toward a rearward portion and has an elongated slot adapted to receive the securing member. 
     
     
         7 ) The assembly of  claim 1 , wherein an energy absorption device is adapted to be carried at least partially by the steering shaft support structure and employed for absorbing energy by way of plastic deformation of the energy absorption device during the forward translation of the steering shaft support structure. 
     
     
         8 ) The assembly of  claim 1 , wherein at least a portion of the steering shaft support structure is pivotally mounted at a forward end of the steering shaft support structure within an automotive vehicle. 
     
     
         9 ) The assembly of  claim 1 , wherein the securing member includes a tilt bolt. 
     
     
         10 ) The assembly of  claim 1 , wherein the steering shaft supports a steering wheel. 
     
     
         11 ) A collapsing steering column assembly, comprising:
 a) an inner column tube;   b) a steering shaft that is supported for rotation at least in part by the inner column tube and having a longitudinal axis;   c) a bracket for carrying the inner column tube and attaching the assembly within a vehicle;   d) a column housing, wherein the column housing and the inner column tube each have a longitudinal axis;   e) a securing member for fixing the position of the inner column tube relative to the column housing by way of the securing member that applies a force to at least one of the column housing or inner column tube for causing a secure engagement of the inner column tube and the column housing; and   f) a breakaway structure;
 wherein the securing member is configured relative to the breakaway structure in a manner such that in an event of an impact exceeding a threshold load, the securing member breaks away from a secure engagement position by way of the breakaway structure and allows the inner column tube to translate forward relative to the column housing. 
   
     
     
         12 ) The assembly of  claim 11 , wherein the assembly includes a longitudinally slotted plate stop device attached to the inner column tube and including one or more base portions at each of its forward end and rearward end portions and opposing side walls that project upward from the one or more base portions and include longitudinally extending side slots adapted to receive the securing member. 
     
     
         13 ) The assembly of  claim 11 , wherein the column housing is pivotally mounted at a forward end of the column housing within an automotive vehicle. 
     
     
         14 ) The assembly of  claim 11 , wherein the bracket includes a pair of generally opposing downwardly oriented walls that flank either or both of at least a portion of the inner column tube or the column housing; and wherein the breakaway structure includes at least one breakaway insert that is operatively attached with at least one of the downwardly oriented walls when the inner column tube, column housing, or both, are in the secure engagement position. 
     
     
         15 ) The assembly of  claim 11 , wherein the assembly includes at least one plastically deformable energy absorption device adapted to be carried at least partially by the column housing, wherein the energy absorption device, when employed, absorbs energy by plastic deformation during the impact after the inner column tube starts to translate along the column housing. 
     
     
         16 ) The assembly of  claim 15 , wherein the securing member is at least partially surrounded by a spacer, and wherein the spacer includes a first portion adapted to oppose the energy absorption device and allow for sliding engagement with the energy absorption device during the impact. 
     
     
         17 ) A collapsing steering column assembly for an automotive vehicle, comprising:
 a) an inner column tube;   b) a steering shaft supported for rotation at least in part by the inner column tube and having a longitudinal axis,   c) a tilt bracket adapted for receiving at least a portion of the inner column tube and for mounting the steering column assembly within the automotive vehicle, the tilt bracket including a pair of opposing side walls;   d) a manually operated steering wheel adjustment subassembly adapted for:
 i) selectively adjusting the steering shaft in a fore or aft direction generally along the longitudinal axis, 
 ii) selectively raising or lowering the steering shaft; or 
 iii) both i) and ii),
 the steering wheel adjustment subassembly including a lever adapted for manually actuating the steering wheel adjustment subassembly, at least one engagement member that is brought into and out of engagement with the inner column tube for selectively locking the steering shaft into a position desired by a user, at least one breakaway insert that detachably mounts the steering wheel adjustment subassembly relative to the tilt bracket, and a fastener assembly that operatively connects the lever, the at least one engagement member and the at least one breakaway insert; 
 
   e) a column housing that is pivotally mounted at a pivot mounting location within the automotive vehicle and that at least partially surrounds the inner column tube to permit steering shaft adjustment by way of the steering wheel adjustment subassembly, the column housing including an elongated longitudinally oriented opening that defines opposing inner wall surfaces that are urged toward the inner column tube for clamping the inner column tube into position using the lever, the inner column tube being clampable in position relative to the column housing, the tilt bracket, or both;
 wherein during a secondary impact, the column housing optionally remains in a generally fixed position relative to the pivot mounting location; 
 wherein at least a portion of the steering wheel adjustment subassembly is adapted to detach from or otherwise become displaced relative to the tilt bracket by way of the at least one breakaway insert and translate during the secondary impact for moving the lever away from the user; and wherein upon translation of the at least one breakaway insert, the inner column tube becomes unclamped relative to the column housing, the tilt bracket or both; and 
 wherein the assembly includes at least one plastically deformable energy absorption device adapted to be carried at least partially by the column housing, wherein the energy absorption device, when employed, absorbs energy by plastic deformation during the secondary impact after the steering wheel adjustment subassembly starts to translate along the column housing. 
   
     
     
         18 ) The assembly of  claim 17 , wherein one or both of the opposing side walls of the tilt bracket has a forward facing cut-out configured to receive the at least one breakaway insert, the forward facing cut-out being generally c-shaped to receive the at least one breakaway insert;
 wherein the at least one breakaway insert has a length and includes a tapered portion that tapers from a forward portion toward a rearward portion, and has an elongated slot adapted to receive a tilt bolt of the fastener assembly and allow upward and downward motion of the steering shaft relative to the tilt bracket; and   wherein during normal operation the tapered portion of the at least one breakaway insert contacts an opposing surface of the tilt bracket and the dimensions of either or both of a taper of the tapered portion or the opposing surface are such that as the secondary impact occurs, the at least one breakaway insert is able to detach from the column housing to allow the forward translation.   
     
     
         19 ) The assembly of  claim 18 , wherein the assembly includes a longitudinally slotted plate stop device disposed in the elongated longitudinally oriented opening of the column housing and attached to the inner column tube; and
 wherein the longitudinally slotted plate stop device includes one or more base portions at each of its forward and rearward end portions, opposing side walls that project upward from the one or more base portions and include longitudinally extending side slots adapted to receive the tilt bolt, at least one transversely extending flange on one or more of the opposing side walls, one or more elastic stoppers at terminal locations of the longitudinally extending side slots, and an upper longitudinal slot adapted to receive the at least one engagement member.   
     
     
         20 ) The assembly of  claim 19 , wherein the tilt bolt is at least partially surrounded by a spacer;
 wherein the spacer is a hollow, generally cylindrical spacer that has a first portion adapted to oppose the energy absorption device and allow for sliding engagement with the energy absorption device during the secondary impact; a second portion that includes one or more projections adapted to be received within the tilt bracket, the column housing, or both, and that will shear during the secondary impact to allow the tilt bolt to translate forward; and at least a portion of the spacer is disposed beneath a portion of the slotted plate stop device for resisting column lash.