Abstract: An earplug of the type that includes a soft foam body (14) and a more rigid core (16) that stiffens the body during its insertion into the ear canal, is mass produced so the front end (30) of the stiff core cannot rub along the surface of the ear canal during insertion. The core is elongated and bonded to the body, and the core has a front end (30) that is recessed from the front end (36) of the body, so the soft foam material of the body prevents the front end of the core from contacting the ear canal. The earplug can be mass produced by extruding the soft foam through an extrusion head (42), around the cores, with a long core device having been cut into the cores and with the extrusion (52) cut at locations to leave foam material forward of each core front end.
Abstract: An earplug includes a body of soft elastomeric material such as a soft resilient foam for insertion in the ear canal, and a stiffener of more rigid material than the body. The stiffener is in the form of a tube rather than a solid rod, so while the stiffener is resistant to column-like collapse, it is easily radially compressed to facilitate compression of the body as it enters the ear canal. The stiffener tube can be filled with soft resilient foam material, to block the passage of sound through the tube. The tubular stiffener can have a slot extending parallel to the length of the stiffener, to allow soft foam material to flow into the tube to fill it, as the foam material that surrounds the tube is molded. Such molding can be accomplished by extruding foam material while the tubular stiffener passes with the extruded foam through the extrusion head.