Patent ID: 7878789

Claim:
A nozzle for extruding cementitious material comprising: an outlet sized and configured to extrude the cementitious material; a material flow pathway configured to channel the cementitious material to the outlet; a vibration-actuated valve interposed in the material flow pathway and containing: a plurality of spaced-apart plates configured to form a plurality of flow channels; and a vibration-generating device coupled to the plates and configured to controllable cause the plates to controllably vibrate, wherein: the vibration-actuated valve is configured such that the cementitious material must flow through the channels formed by the plates in order to reach the outlet; and the spacing between the plates and the surface of the plates are in amounts which collectively cause: the flow of the cementitious material though the plurality of flow channels to be blocked when the vibration-generating device is not vibrating; and the cementitious material to flow through the plurality of flow channels simultaneously when the vibration-generating device is vibrating.