The invention relates to an apparatus similar to that described in U.S. Pat. No. 4,534,817.
In the portable apparatus of that reference the polymeric tape to be welded is clamped between two welding members, a backfoot and the tip of an ultrasonic transducer. The tip is vibratingly driven in longitudinal direction, so that a weld is formed by the frictional heat generated in the process. However, the energy that can be generated is limited, so that the use of this known apparatus has restrictions with regard to the thickness of the tape to be used and the type of tape.
Another ultrasonic bundle-tying apparatus having the same limitation is known from U.S. Pat. No. 4,265,687.
It should be noted that the welding together of components of thermoplastic material by the application of a high-frequency electric field to the desired welding area is known in itself, see e.g. U.S. Pat. No. 4,247,591, GB 565,592 and FR 2,149,633. In the latter patent specification the use of a frequency of 2450 MHz is disclosed. However, these publications do not refer to an apparatus of the type for making a tightly closed loop of a tape around an object.
USPTO Backgrounds
USPTO Backgrounds