Energy-absorbing device and method of making the same

Claim 1

An energy-absorbing device of the type compromising a pair of elongated members that are constrained to lengthwise motion relative to one another and are normally in lengthwise overlapping relation, one of said members being displaceable lengthwise along the other in response to an endwise force that is in excess of a predetermined magnitude, said device being characterized by: A. one of said members comprising a wall of substantially hard but elastic material which is undulatory in transverse section to define a plurality of bays that open in alternately opposite transverse directions and each of which bays extends a substantial distance along the member, the undulatory shape of said wall providing for its elastic deformation transversely of its length; B. the other of said members having a plurality of spherical indentations that open into each of certain said bays and are longitudinally spaced from one another; and C. a hard ball for each of said indentations, each of said balls being confined between its indentation and the bay into which the same opens and having a diameter large enough to be held against displacement relative to said other member by its engagement in its indentation and to effect local elastic deformation of the first-mentioned member.

Claim 11

The method of making an energy-absorbing device of the character described which is characterized by: A. producing a hollow inner member having a wall of substantially hard but elastically deformable material, which wall, along a substantial portion of the length of the inner member, has a circumferentially undulating configuration in cross section and thus defines a plurality of radially outwardly opening bays that alternate around the circumference of the inner member with radially inwardly opening bays; B. producing a tubular outer member of substantially hard material that is plastically deformable under load and which is of such diameter that that the inner member is freely axially receivable therein; C. by means of a readily frangible bonding material securing a plurality of hard balls to the inner member at axially spaced locations in each of said radially outwardly opening bays, said balls being of such diameter as not to interfere with free axial insertion of the inner member into the outer member; D. establishing and maintaining the inner and outer members in telescoped relationship; E. establishing rigid backup means inside the inner member radially inwardly opposite each of said balls for resisting radially inward displacement of the balls in response to radially inward force upon them; F. with the rigid backup means in place, forcefully convergingly jaws against the outer surface of the outer member in the neighborhood of each of the balls, to form a radially inwardly opening socket in the outer member for each ball by which the ball is confined against displacement relative to the outer member; G. releasing said jaws from the outeR member; and H. withdrawing the backup means from the inner member.

Claim 12

The method of making an energy-absorbing device of the character described which is characterized by: A. producing a hollow inner member having a wall of substantially hard but elastically deformable material, which wall, along a substantial portion of the length of the inner member, has a circumferentially undulating configuration in cross section and thus defines a plurality of radially outwardly opening bays that alternate around the circumference of the inner member with radially inwardly opening bays; B. producing a tubular outer member of substantially hard material that is plastically deformable under load and which is of such diameter that that the inner member is freely axially receivable therein; C. by means of a readily frangible bonding material securing a plurality of hard balls to the inner member at axially spaced locations in each of said radially outwardly opening bays, said balls being of such diameter as not to interfere with free axial insertion of the inner member into the outer member; D. establishing and maintaining the inner and outer members in telescoped relationship; E. establishing rigid backup means inside the inner member radially inwardly opposite each of said balls for resisting radially inward displacement of the balls in response to radially inward force upon them; F. with the rigid backup means in place, forcefully convergingly jaws against the outer surface of the outer member in the neighborhood of each of the balls, to form a radially inwardly opening socket in the outer member for each ball by which the ball is confined against displacement relative to the outer member; G. releasing said jaws from the outeR member; and H. withdrawing the backup means from the inner member.