Safety belt reel with torsion rod

Claim 1

In a safety belt wind-up device having a belt wind-up drum with a hollow interior, an energy conversion device comprising a torsion rod mounted in the hollow interior of the wind-up drum and having a first and second ends corresponding to respective first and second ends of the wind-up drum, means for rigidly connecting said first end of said torsion rod to the corresponding first end of the wind-up drum, the second end of the wind-up drum being freely rotatable, means actuable for anchoring said torsion rod against rotation at said second end thereof so that when said second end of said torsion rod is anchored against rotation, said torsion rod absorbs energy by torsion of said first end thereof relative to said anchored second end thereof, a rigid tube surrounding said torsion rod and having a peripheral wall disposed between said torsion rod and the inner surface of the belt wind-up drum for limiting bending of said torsion rod and for preventing a bent torsion rod from jamming against the drum and interfering with the energy conversion characteristics of said torsion rod.