Apparatus and method of manufacturing an elastic composite structure for an absorbent sanitary product

A method of manufacturing an elastic composite structure comprising:

• positioning an elastic thread assembly between a first web layer and a second web layer, the elastic thread assembly comprising a plurality of unbonded multifilament elastic threads;
• bonding the first web layer to the second web layer via a bond pattern comprising a plurality of bond lines having pairs of adjacent bonds;
• anchoring the elastic thread assembly within a passage formed between the first web layer and the second web layer, the passage defined between facing edges of pairs of adjacent bonds in the plurality of bond lines;
• feeding the plurality of unbonded multifilament elastic threads under tension in a machine direction toward an ultrasonic bonding assembly;
• and
• combining together a subset of the plurality of unbonded multifilament elastic threads upstream of the ultrasonic bonding assembly so that the elastic thread assembly is now combined,
• wherein the facing edges are spaced apart by a distance that is smaller than an overall diameter of the elastic thread assembly in a non-tensioned state and that is larger than a strand diameter of the plurality of elastic threads in a non-tensioned state.