Patent ID: 8381950
Filing Date: 2013-02-26
Classification: B05C

Abstract:
1. A rodless dispenser for extrudable material, the rodless dispenser comprising: a first translatable piston (first piston) having a piston head configured to apply a force against a second translatable piston (second piston) in a replaceable tube of extrudable material, the first piston having a skirt, which extends at least part way around the first piston face, the skirt extending from the first piston face toward a base of the first piston, the first piston base being opposite the first piston face, the first piston also having a geometric center axis that extends through the first piston base and the first piston face; a push chain (chain) comprised of a plurality of links, the links being configured to be rotatable around each other in a first direction and incapable of rotating around each other in an opposite, second direction, the chain capable of exerting a compressive force when said links are urged to rotate in said second direction, a first end of the chain being attached to the first piston base at an application point offset from the first piston geometric center axis by a first distance, the application point being located below the geometric center axis of the first piston; wherein, when a replaceable tube of extrudable material is in the rodless dispenser and said first piston is against the second piston, a compressive force applied by the push chain creates an opposing reactive force against the first piston face from the second piston, the opposing reactive force from the second piston causing the first piston to urge at least some of the push chain links to rotate in the second direction.