Roller unit for winding-up safety belts for motor vehicles

Claim 1

A roller unit for winding up a safety belt for motor vehicles with a built-in device for blocking the pulling-out of the safety belt in response to certain movements and positions of a vehicle equipped with said unit, said device including in combination: a sensor comprising a magnetically attractible spherical inertia body provided as a steel ball having a center of gravity with axes passing therethrough as well as being responsive to accelerating and retarding movement of a vehicle equipped with said device, a ball cup as a support with a center for receiving the ball, said ball resting in said ball cup as the support having inclined surfacing sloping upwardly from the center of the ball cup to permit ball movement responsive to vehicle movement, rotatable means for winding up a safety belt, a blocking disc rotatably connected to said rotatable means, ratchet gear means connected to said blocking disc for rotation therewith, pawl means resting on said ball and operable to engage and disengage said ratchet gear means upon upward movement of the ball upon said inclined surfacing of said ball cup, said pawl means being operable by said ball upon upward movement on said inclined surfacing of said ball cup to move from an ineffective position in which it is disengaged from said ratchet gear means into an effective position in which it engages said ratchet gear means and thereby blocks rotation of said blocking disc and said rotatable means, and an electromagnet with a coil having an axis arranged closely in the vicinity of said ball in said ball cup with minimum spacing therebetween, said coil being operable when energized to exert an attractive force directly upon said ball to cause the ball to move upwardly on said inclined surfacing of said ball cup to positively move said pawl means upwardly into engagement with said ratchet gear means thereby causing blockage of said rotatable means for the safety belt, the axis of the coil of said electromagnet being spaced upwardly from one of the axes of said ball which passes through the center of gravity of said ball and parallel to said axis of the coil so that electromagnet forces are effective in a direction corresponding to ball movement on said inclined surfacing of said ball cup and substantially parallel to said coil axis by a distance necessary to cause said ball to move said pawl means into its effective position.