An expansion joint or movement joint is an assembly designed to safely absorb the heat-induced expansionand contraction of construction materials, to absorb vibration, to hold parts together, or to allow movement due to ground settlement or earthquakes.
Rubber expansion joints are mainly manufactured by manual wrapping of rubber sheets and fabric reinforced rubber sheets around a bellows-shaped product mandrel. Besides rubber and fabric, reinforced rubber and/or also steel wires or metal rings are added for additional reinforcement. After the entire product is build up on the mandrel, it is covered with a winding of (nylon) peel ply to pressurize all layers together before pressurization. Because of the labor-intensive production process