Abstract: Foam earplugs (90) are produced by extruding foamable material through a nozzle (12) having a throat (30) where the nozzle diameter is smallest, to produce an extrusion (34) that expands in diameter along an expansion zone (D) as the extrusion moves forward. Applicant moves dies (70, 72) against opposite sides of the extrusion and then moves the dies forward with the moving extrusion while the foam solidifies into earplugs. The earplugs to be formed have sealing portions that seal to a person's ear canal, of a maximum diameter G of about 0.4 inch, and the nozzle throat has a diameter B no more than 0.1 inch to provide a long expansion zone so the dies can begin to mold the extrusion while the extrusion is still expanding in diameter.

Abstract: An earplug has a single very long main flange with a maximum diameter that is at least 80% of the length of the main flange, and at least 55% of the entire length of the earplug except for the stem. This allows the outside of the long flange to extend at a very small angle to the axial direction, and apply a constant force against the walls of the ear canal, for good and comfortable sealing to the ear canal.

Abstract: Earplugs (22, 24) and a combination (20) of a pair earplugs and a cord (26) that joins them, each can be detected by metal and/or magnetic detectors even if the parts of the combination becomes separated and fall into a batch of food, etc. Each earplug includes an earplug core (32) formed of a first elastomer with a multiplicity of metal-mag detectable particles (36) (particles detectable by electrical or magnetic detectors) embedded in the first elastomer, and an earplug covering (32) of a second elastomer (that may be the same as the first one) that is devoid of such particles. The cord includes a cord core (50) formed of a first flexible polymer with metal-mag detectable particles embedded therein, and a cord covering (54) formed of a second polymer that is devoid of such particles. The particles are preferably of iron, which is magnetically detectable but that can mark skin or clothing that it contacts, but which is isolated from the skin and clothing by the earplug and cord coverings.

Abstract: Foam earplugs (90) are produced by extruding foamable material through a nozzle (12) having a throat (30) where the nozzle diameter is smallest, to produce an extrusion (34) that expands in diameter along an expansion zone (D) as the extrusion moves forward. Applicant moves dies (70, 72) against opposite sides of the extrusion and then moves the dies forward with the moving extrusion while the foam solidifies into earplugs. The earplugs to be formed have sealing portions that seal to a person's ear canal, of a maximum diameter G of about 0.4 inch, and the nozzle throat has a diameter B no more than 0.1 inch to provide a long expansion zone so the dies can begin to mold the extrusion while the extrusion is still expanding in diameter.

Abstract: An earplug (10) of the type that is molded of elastomeric material and that has a flange (14) that seals to the walls of a person's ear canal as a stem (12) is pushed forward into the ear canal. Instead of using three or four flanges, applicant's earplug has a single very long main flange (14) with a maximum diameter (D) that is at least 80% of the length (L) of the main flange, and at least 55% of the entire length (B) of the earplug except for the stem. This allows the outside of the long flange to extend at a very small angle (C) to the axial direction, and apply a constant force against the walls of the ear canal, for good and comfortable sealing to the ear canal.

Abstract: An earplug (10) that includes a soft foam body (12) and a stiffener (14) in the body, is produced by a method that has minimum steps and that results in an earplug of attractive design and that uses a minimum of material. One method includes molding an earplug body in a body cavity (52) while a mandrel (56) lies in the body cavity. After the foam material in the body cavity has at least partially solidified, the mandrel is removed, leaving an empty stiffener cavity (60) in the foam body (12). With the body remaining in the body mold (54), flowable stiffener material (14A) is poured into the stiffener cavity of the body and allowed to solidify, to produce an earplug with a molded-in stiffener (14). Another method, results in an earplug (90) with a stem (95) having a rearwardly-projecting stem portion (96). This method includes molding a stem rear portion (96) in a stiffener cavity (110) while allowing stiffener material to project forward of the rear portion to form a stem free front portion (120).

Abstract: Earplugs with soft foam bodies and with stiffeners in the bodies, are molded by suspending the stiffener in the body mold cavity using a pin (60) that extends into a passage (56) at the rear of the body. Each stiffener is tapered in diameter, with a rear end (34) of greatest diameter.

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.