Abstract: An enclosure for isolating noise sources composed of four walls and a ceiling, in which some or all of the sides and top consist of a muffler barrier including one or more air paths transverse to the principal direction of sound transmission through the structure. Various types of component muffler barriers are illustrated which include double leaf structures lined with sound absorbing material where the two leaves are disposed in spaced apart relation and include oppositely disposed air intakes and air exhausts to provide the intervening air paths. In one embodiment, components comprise corrugated panels of sound absorbing material disposed in face-to-face relation to provide multiple air channels.

Abstract: A stored energy ejector mechanism is disclosed and described and includes an ejector plunger member which is propelled by a spring-bias induced by an actuator lever actuated by a stroke of a punch press and the like. The stored energy in these springs is released and the propelling or ejection motion of a plunger member is begun by the actuation of a trigger mechanism whose release time is selectively established and preferably occurs during the same stroke of the press mechanism in which is produced the loading of the springs. Although primarily for use with a punch press to provide a substantially quiet ejector action, this stored energy is equally applicable to other operations such as providing an ejector mechanism for use with a conveying or line inspection system employing linear motion.