Collapsible steering column assembly

Abstract

A collapsible steering column assembly preferably has a collapsible steering shaft that extends rotatably along a centerline and a collapsible column that houses and co-extends with the shaft. The column preferably has inner and outer jackets that retract axially to collapse the column. An energy absorbing device has a member engaged between the inner and outer jackets and controls the collapse of the column generally via a high load stage and a low load stage of operation. The member is preferably elongated axially having a distal end that is looped over and spaced radially outward from the remainder of the member. The distal end is attached disengagably to the outer jacket via a pin received in a hole in the distal end and a fuse engaged operably to the pin and attached to the outer jacket.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a steering column assembly of the present invention illustrated with a two-stage E/A device and without a collapsible steering shaft of the assembly to show internal detail;

FIG. 2 is a cross section of the steering column assembly taken along line 2-2 of FIG. 1 and with the collapsible steering shaft;

FIG. 3 is an enlarged partial side view of the steering column assembly;

FIG. 4 is a perspective view of a strap of the E/A device;

FIG. 5 is an enlarged partial perspective view of the steering column assembly;

FIG. 6 is a partial cross section of the assembly taken along line 6-6 of FIG. 5;

FIG. 7 is a partial perspective view of a second embodiment of a steering column assembly and similar in perspective to FIG. 5;

FIG. 8 is a partial cross section of a third embodiment of a steering column assembly and similar in perspective to FIG. 2;

FIG. 9 is a partial cross section of a fourth embodiment of a steering column assembly; and

FIG. 10 is a partial cross section of a fifth embodiment of a steering column assembly.

Claims

1. A collapsible steering column assembly for a vehicle comprising: a collapsible steering shaft defining a centerline and extending rotatably along the centerline;first and second jackets co-extending with and rotatably supporting the steering shaft, wherein the first and second jackets are constructed and arranged to collapse axially with respect to one another;an energy absorption device having a strap defining first and second portions with each of the portions attached rigidly to the first jacket and one of the portions releasably attached portions to the second jacket to define a two stage energy absorption device.

2. The collapsible steering column assembly set forth in claim 1 wherein the energy absorption device includes a fuse attached to the second jacket and a pin projecting operatively outward from the fuse and extending through a hole in the strap for releasably engaging one of the portions of the strap to the second jacket.

3. The collapsible steering column assembly set forth in claim 1 wherein the strap is elongated and extends axially with respect to the centerline.

4. The collapsible steering column assembly set forth in claim 1 wherein the strap is folded over upon itself to define a folded end and the first and second portions with the first portion having a first end and the second portion having a second end.

5. The collapsible steering column assembly set forth in claim 4 wherein the first portion of the strap extends longitudinally between a third end and the first end and the second portion of the strap extends longitudinally between a fourth end and the second end with the third and fourth ends defining the folded end.

6. The collapsible steering column assembly set forth in claim 1 further wherein the first portion includes at least one laterally projecting tab in contact with a stop carried by the second jacket.

7. The collapsible steering column assembly set forth in claim 1 wherein the first portion is engaged to the second jacket by a threaded bolt.

8. The collapsible steering column assembly set forth in claim 2 wherein the fuse is of a pyrotechnic type.

9. The collapsible steering column assembly set forth in claim 1 wherein the first jacket has an inner tubular portion and the second jacket has an outer tubular portion located radially outward from the inner tubular portion.

10. A steering column assembly for a vehicle comprising: a collapsible steering shaft extending and rotating about a centerline;a collapsible steering column co-extending with and housing the steering shaft, the column having an outer jacket and an inner jacket projecting axially outward from the outer jacket in a forward direction;an energy absorption device having high and low load stages of operation, a member engaged to the inner jacket, a pin removably connected to the member, a fuse connected operably to the pin and engaged to the outer jacket; andwherein the fuse is constructed and arranged to disengage the pin from the member upon receipt of a given condition to define the low load stage of operation.

11. The steering column assembly set forth in claim 10 wherein the given condition is at least one of a vehicle speed signal, a driver size signal, a driver position signal, and a seat belt function signal.

12. The steering column assembly set forth in claim 10 further comprising: the member being elongated axially and having a forward end engaged to the inner jacket and an opposite distal end; anda hole in the distal end for removable receipt of the pin.

13. The steering column assembly set forth in claim 12 wherein the elongated member is looped over itself so that both the forward end and the distal end project in the forward direction.

14. The steering column assembly set forth in claim 13 wherein the distal end is spaced radially outward from the forward end.

15. The steering column assembly set forth in claim 14 further comprising: a first layer of the member having the forward end and the distal end;a second layer of the member substantially co-extending with the first layer from a second rearward end engaged to the inner jacket and a second distal end engaged to the outer jacket; andwherein the second layer deforms during both the low and high load stages of the energy absorbing device.

16. The steering column assembly set forth in claim 15 further comprising: a third load stage of the energy absorbing device;a third layer of the member extending axially from a third forward end engaged to the inner tube and a third distal end;a second fuse engaged to the outer tube; anda second pin connected operably to the second fuse and releasably to the third distal end.

17. The steering column assembly set forth in 10 wherein the member is located at least in-part in an elongated recess extending axially and defined between the outer and inner jackets.