Patent ID: 8517432

Claim:
A sand dosing and blocking device ( 1 ) for sand spreading systems for vehicles comprising a sand reservoir ( 2 ) with an outlet opening ( 4 ) that is adapted to be closed by means of a closing element ( 3 ), for dosed discharge of the sand to a conveyor unit ( 5 ) that is activated pneumatically, wherein the closing element ( 3 ) is formed by a lifting rod ( 7 ) of an electrically operable lifting magnet( 6 ), wherein the lifting magnet ( 6 ) is arranged inside the sand reservoir ( 2 ) in a region of the outlet opening ( 4 ), and the lifting magnet ( 6 ) is connected with a control device ( 22 ), which control device ( 22 ) includes frequency controlling of the lifting magnet ( 6 ), wherein the control device ( 22 ) is connected with a device for detecting a velocity of the vehicle, and includes a velocity-dependent lifting frequency regulation of the lifting magnet.