Patent ID: 7229100

Claim:
An apparatus comprising: a cylinder; a piston movable in said cylinder to effect pretensioning of vehicle seat belt webbing, said piston having a bore with a first volume; and a fluid source for providing fluid under pressure to move said piston in said cylinder, said fluid source comprising a propellant container defining a propellant chamber and a propellant in said propellant chamber, said propellant being ignitable to produce fluid under pressure; said propellant container having portions disposed in said bore in said piston and having a second volume that is less than said first volume of said piston bore, said propellant container portions being movable into said bore during assembly of said apparatus and, thereafter, being releasably held in place in said bore with a friction fit, said propellant container comprising first and second retainers spaced apart with said propellant held between them.