Passive type vehicle occupant restraint belt system

In a passive vehicle occupant restraint belt system having a belt guide member that is coupled to a restraint belt and is movable between a restraint location in which the belt engages an occupant and a release location in which the belt releases the occupant, a reversible drive motor, control means for activating the motor to drive it in one direction in response to opening of the vehicle door and in the opposite direction in response to closing of the vehicle door, a semi-flexible drive element coupled to the guide member, and a reduction device for transmitting power from the motor to the drive element, the improvement wherein the reduction device comprises a housing having first and second closed compartments separated by a common dividing partition, an output shaft journaled in the partition and having a first portion located in the first compartment and a second portion located in the second compartment;

• an output drive element affixed to the first portion of the output shaft and coupled to the guide element to drive it;
• an input shaft having its axis disposed orthogonically to the axis of the output shaft and extending into the second compartment;
• a worm gear affixed on the input shaft;
• a worm wheel rotably carried on the second portion of the output shaft and meshing with the worm gear;
• and an enclosed friction coupling received within the second compartment and interposed between the worm wheel and the output shaft, the compartmentalization of the casing and enclosing of the friction coupling enabling the input and output gears to be lubricated while excluding lubricant from the friction coupling.