Patent ID: 8025087

Claim:
An ultrasonic vibration welder comprising: a horn; a vibration transmission rod having a first end, a surface of which serves as a vibration-and-pressure application surface, the vibration transmission rod having a polygonal cross section, the vibration transmission rod being disposed at an end of the horn in such a manner that the vibration transmission rod extends perpendicularly to an axis of the horn, the vibration transmission rod having a projection that extends perpendicularly to an axis of the vibration transmission rod at a nodal point thereof, the vibration transmission rod having a resonant frequency in an axial direction of the horn and a resonant frequency in a direction intersecting the axis of the horn, the resonant frequencies being different from each other by at least 500 Hz; and a mass formed separately from the vibration transmission rod, the mass having a recess in an end surface thereof for receiving a second end of the vibration transmission rod, the end surface of the mass being configured to contact the projection of the vibration transmission rod while the recess receives the second end of the vibration transmission rod, the mass pressing the nodal point of the vibration transmission rod.