Energy absorber for collapsible steering columns or the like

Claim 2

In an energy absorber of the type which includes a pair of telescopically related tubes having engaged between the walls thereof with predetermined interference fit a complement of deformer balls adapted to roll over the walls of the tubes during telescoping movement of the tubes and to plastically deform such walls, the improvement which comprises means defining in the wall of at least one of said tubes a selected number of recesses of a number less than in said complement and of predetermined depth and limited length extending in the direction of telescoping movement of the tubes, said recesses receiving certain of said complement of balls, the depth of said recesses and the size of said certain balls being related such that the latter are adapted to travel the recesses in unison with the remainder of the ball complement outside the recesses during such tube telescoping and freely of any substantial interfering engagement thereof between the walls of the tubes, said certain balls at the end of such travel being engageable with predetermined substantial interference fit between the walls of the tubes to roll during further telescoping movement thereof and plastically deform such walls, whereby said energy absorber provides a first level of energy absorption from the effect of interfering engagement of said remainder of the ball complement and a second level of energy absorption comprising the effect of interfering engagement of said certain balls.

Claim 3

In the improved energy absorber set forth in claim 1, the lengths of the several said recesses available for said substantially non-interfering engagement of the balls therein being predeterminedly different whereby said end of travel among said certain balls occurs at different points in the telescoping of said tubes and graduated change is had between said first and second levels of energy absorption.

Claim 4

In an energy absorber of the type which includes a pair of telescopically related tubes having engaGed between the walls thereof with predetermined interference fit a complement of deformer balls adapted to roll over the walls of the tubes during telescoping movement of the tubes and to plastically deform such walls, the improvement which comprises means defining in the wall of at least one of said tubes a selected number of recesses of a number less than in said complement and of predetermined depth and limited length extending in the direction of telescoping movement of the tubes, and deformer balls in said recesses predeterminedly larger in size than the remainder of the balls in said complement outside said recesses yet of such size with respect to the depth of said recesses as to be adapted to travel the recesses in unison with said remainder during such tube telescoping freely of any substantial interfering engagement between the walls of the tubes, said larger balls at the end of such travel being engageable with predetermined substantial interference fit between the walls of the tubes to roll during further telescoping movement thereof and plastically deform such walls, whereby said energy absorber provides a first level of energy absorption from the effect of interfering engagement of said remainder of the ball complement and a second level of energy absorption comprising the effect of interfering engagement of said larger balls.

Claim 5

In an energy absorber of the type which includes a pair of telescopically related tubes having engaGed between the walls thereof with predetermined interference fit a complement of deformer balls adapted to roll over the walls of the tubes during telescoping movement of the tubes and to plastically deform such walls, the improvement which comprises means defining in the wall of at least one of said tubes a selected number of recesses of a number less than in said complement and of predetermined depth and limited length extending in the direction of telescoping movement of the tubes, and deformer balls in said recesses predeterminedly larger in size than the remainder of the balls in said complement outside said recesses yet of such size with respect to the depth of said recesses as to be adapted to travel the recesses in unison with said remainder during such tube telescoping freely of any substantial interfering engagement between the walls of the tubes, said larger balls at the end of such travel being engageable with predetermined substantial interference fit between the walls of the tubes to roll during further telescoping movement thereof and plastically deform such walls, whereby said energy absorber provides a first level of energy absorption from the effect of interfering engagement of said remainder of the ball complement and a second level of energy absorption comprising the effect of interfering engagement of said larger balls.

Claim 6

In the improved energy absorber set forth in claim 3, the lengths of the several said recesses available for said substantially non-interfering engagement of the balls therein being predeterminedly different whereby said end of travel among said oversized balls occurs at different points in the telescoping of said tubes and graduated change is had between said first and second levels of energy absorption.

Claim 7

An energy absorber including a pair of telescopically related tubes, a first set of deformer balls arranged in at least two spaced annular rows and engaged between the walls of said tubes with predetermined interference fit to roll over the walls of the tubes during telescoping movement of the tubes and to plastically deform such walls, means defining in the wall of at least one of said tubes and for each of said annular rows a selected number of recesses of predetermined limited length extending in the direction of telescoping movement of the tubes, said recesses being staggered angularly in each said row with respect to the said first set of balls in that row, and a set of further balls in said recesses predeterminedly oversized with respect to said first set of balls, a ball carrying sleeve intermediate said tubes and receiving both said sets of balls and operative to cause said oversized ones thereof to travel the recesses in unison with rolling of said first set of balls during telescoping of said tubes, the size of said oversized balls being such with respect to the depth of said recesses that said traveling of said oversized balls occurs freely of any substantial interfering engagement between the walls of the tubes, said oversized balls at the end of such travel being engageable with predetermined substantial interference fit between the walls of the tubes to roll during further telescoping movement thereof and plastically deform such walls, whereby said energy absorber provides a first level of energy absorption from the effect of interfering engagement of said remainder of the ball complement and a second level of energy absorption comprising the effect of interfering engagement of said oversized balls.

Claim 8

An energy absorber including a pair of telescopically related tubes, a first set of deformer balls arranged in at least two spaced annular rows and engaged between the walls of said tubes with predetermined interference fit to roll over the walls of the tubes during telescoping movement of the tubes and to plastically deform such walls, means defining in the wall of at least one of said tubes and for each of said annular rows a selected number of recesses of predetermined limited length extending in the direction of telescoping movement of the tubes, said recesses being staggered angularly in each said row with respect to the said first set of balls in that row, and a set of further balls in said recesses predeterminedly oversized with respect to said first set of balls, a ball carrying sleeve intermediate said tubes and receiving both said sets of balls and operative to cause said oversized ones thereof to travel the recesses in unison with rolling of said first set of balls during telescoping of said tubes, the size of said oversized balls being such with respect to the depth of said recesses that said traveling of said oversized balls occurs freely of any substantial interfering engagement between the walls of the tubes, said oversized balls at the end of such travel being engageable with predetermined substantial interference fit between the walls of the tubes to roll during further telescoping movement thereof and plastically deform such walls, whereby said energy absorber provides a first level of energy absorption from the effect of interfering engagement of said remainder of the ball complement and a second level of energy absorption comprising the effect of interfering engagement of said oversized balls.