Abstract: A wiper assembly has an arm head which reciprocates with respect to a center line of a wiper arm by receiving motive force from a reciprocating rod. An elastic component is coaxially provided proximate to the center of rotation. When the coefficient of friction between the wiper blade and the windshield surface is inversely proportional to the speed of the wiper blade causing self-induced vibration in certain circumstances, the wiper blade tends to screech, skip or chatter across the windshield surface. Such vibration is suppressed by the elastic component, thereby permitting smooth reciprocal motion of the wiper assembly.

Abstract: A resonator for internal combustion engines having intake and exhaust pipes connected with a cylinder of said internal combustion engines comprising resonator means for absorbing resonant noises generated in said engines, a plurality of tubular connecting members disposed between said resonator means and one of said pipes for forming a continuous passage from said one pipe to said resonator means, and switch means connected with said tubular connecting means for changing said tubular connecting members in accordance with operational conditions of said engines to absorb said noises from said engines.

Abstract: A resonator for internal combustion engines, having an enclosed chamber of predetermined volumn connected to an intake duct by a tubular connecting member which is composed of an external member and an internal member. The internal member is disposed within the external member and moved by an actuator which is controlled by an electrical signal corresponding to a resonant frequency calculated by a computer in synchronism with engine rotational speeds. The resonator thereby functions to absorb resonant noises from the engines by appropriately changing the length and/or cross-sectional area of the tubular connecting member.