Seat belt webbing pretensioner using MEMS devices

A pretensioner for vehicle seat belt webbing, said pretensioner comprising:

• a member movable by an actuating fluid to tension the seat belt webbing;
• and
• at least one multi-layered device for providing actuating fluid to move said member, said device including:
• an outer layer having a plurality of individually rupturable segments;
• a middle layer having a plurality of individual chambers associated in a one-to-one relationship with said rupturable segments of said outer layer and being closed by said rupturable segments, each one of said chambers having contents heatable to increase the pressure in said one chamber;
• and
• a base layer having a plurality of individually energizable electric heating elements associated in a one-to-one relationship with said chambers for, when energized, heating the contents of said chambers;
• each one of said rupturable segments being rupturable due to an increase in pressure in its associated chamber to enable flow of said actuating fluid out of said chamber;
• and
• means for selectively energizing said individually energizable electric heating elements.

A pretensioner comprising:

• a member movable to tension seat belt webbing;
• an array of individually energizable devices for producing combustion products for moving said member;
• and
• means for energizing selected ones of said array of individually energizable devices,
• said energizing means including a base that extends across said array and a plurality of electric heating elements associated with each of said energizable devices and connected to the base with terminal pins that are received in said base,
• said energizing means further comprising control means for directing electric current into selected ones of said plurality of electric heating elements to energize said selected ones of said energizable devices for producing combustion products for moving said member.

A pretensioner for pretensioning vehicle seat belt webbing, said pretensioner comprising:

• a member movable by an actuating fluid to tension the seat belt webbing;
• and
• at least one microelectromechanical system (MEMS) device energizable to supply actuating fluid to move said member,
• said MEMS device including a quantity of fluid that is heated and pressurized upon energizing of said MEMS device to produce said actuating fluid.

A pretensioner for pretensioning vehicle seat belt webbing, said pretensioner comprising:

• a member movable by an actuating fluid to tension the seat belt webbing;
• and
• at least one microelectromechanical system (MEMS) device energizable to supply actuating fluid to move said member,
• said MEMS device has a size in the range of from about one-quarter inch square to about one inch square and includes an array of at least three plenum chambers.