US Patent 7479148 Ultrasonic shear with asymmetrical motion

Devices providing ultrasonic clamped cutting using asymmetrical motion include a housing and ultrasonic waveguide. A longitudinal axis extends through the center of mass of the ultrasonic waveguide. An actuating assembly provides opposable movement of a clamp arm with respect to the cutting blade, the movement defining a vertical plane having a vertical axis orthogonal to both the longitudinal axis and a horizontal axis. An end-effector coupled to the ultrasonic waveguide includes a cutting blade that cuts using ultrasonic motion. The blade's center of mass may be offset from the longitudinal axis, providing motion of the blade in both the longitudinal and vertical axes concurrently. Excursion of the cutting blade in the direction of the horizontal axis that may be limited to less than 92%, and in the direction of the vertical axis of more than 8%, of an excursion of the cutting blade in the direction of the longitudinal axis.