Patent ID: 7360750
Filing Date: 2008-04-22
Classification: B07C,F16K,Y10T

Abstract:
1. A piezoelectric air valve to be used for a granular material sorting machine comprising: an air valve main body including an air pressure chamber for receiving compressed air fed from an air pressure feeding means and an air outlet extending from the air pressure chamber to an exterior; a valve body for controlling operations to open and close a space between the air pressure chamber and the air outlet; a piezoelectric element for generating driving force required for the operations to open and close the valve body in the form of displacements; a pair of displacement enlarging mechanisms arranged symmetrically with respect to the air outlet as upper and lower displacement enlarging mechanisms, each displacement enlarging mechanism enlarges the displacements generated by the piezoelectric element and then applies the enlarged displacements to the valve body; and wherein the valve body, each displacement enlarging mechanism and the piezoelectric element are mechanically connected to one another, and on one hand, the operation to open the valve body is performed in accordance with the displacements generated by the piezoelectric element and subsequently enlarged by the displacement enlarging mechanism when a voltage is applied to the piezoelectric element and, on the other hand, the operation to close the valve body is performed in accordance with resetting force of the piezoelectric element when the voltage applied to the piezoelectric element is stopped; and wherein the upper displacement enlarging mechanism comprises: a first hinge member, one end of which is jointed to the air valve main body and operates as the fulcrum; a second hinge member, one end of which is jointed to the piezoelectric element in a substantially parallel relation with respect to the first hinge member and operates as the point of power; a first arm member to which the respective other ends of the first and second hinge members are jointed, the first arm member extending a distance longer than the distance between the first hinge member and the second hinge member, and the tip portion of which operates as the point of action; a first spring member, one end of which is jointed to the tip portion of the first arm member and the other end of which is jointed to a first part of the valve body; and wherein the lower displacement enlarging mechanism comprises: a third hinge member, one end of which is jointed to the air valve main body and operates as the fulcrum; a fourth hinge member, one end of which is jointed to the piezoelectric element in a substantially parallel relation with respect to the third hinge member and operates as the point of power; a second arm member to which the respective other ends of the third and fourth hinge members are jointed, the second arm member extending a distance longer than the distance between the third hinge member and the fourth hinge member, and the tip portion of which operates as the point of action; and a second spring member, one end of which is jointed to the tip portion of the second arm member and the other end of which is jointed to a second part of the valve body.