Ultrasonic rotary horn and application of same

摘要

An ultrasonic rotary horn intended to be excited at a frequency of from about 18 to about 60 kHz, which horn comprises a shaped, solid metal object having a radial surface terminated by a first end and a second end, and a rotational axis, in which each of said ends is defined by a surface and said object is axially symmetrical, whereby diameter, width, and thickness are selected for a desired frequency so that said horn, upon being excited by ultrasonic energy at such frequency which is input at the rotational axis at, and substantially perpendicular to, one or both ends, is adapted to resonate in a manner such that: (1) the excited end moves substantially in phase with the movement of the source of excitation; (2) the opposing end, whether or not it is actively excited, moves substantially out of phase with the movement of the excited end; (3) said radial work-contacting surface also moves substantially out of phase with the movement of the excited end; and (4) said horn exhibits a single nodal point at its geometric center. The diameter of said horn is in the range of from about 4 cm to about 19 cm. The width of said horn at said radial surface is from about 0.6 cm to about 13 cm. The thickness of said horn at the rotational axis thereof is from about 0.6 cm to about 15 cm and is independent of the width of said horn at said radial surface. Said horn has a mass in the range of from about 0.06 kg to about 30 kg. Said first and/or second end have a substantial concave configuration, whereby a horn having a thickness greater than or the same as the diameter of said horn is excluded; and the width of said horn at the radial surface and the thickness of said horn are such that the amplitude profile is essentially flat over the width of said radial surface. The horn may include hubs on each of the two ends; the hubs being integral parts of the horn; the horn may also include threaded studs which protrude from the ends or from the hubs. The ultrasonic rotary horn of the present invention is particularly useful in continuous processes for bonding together two or more layers of at least partly thermoplastic materials, such as woven and nonwoven fabrics and films.