Abstract: An exhaust muffler for an internal combustion engine, comprising a hollow casing defining a plurality of chambers which are communicated with each other by way of small holes, an exhaust inlet tube fixedly attached to an exhaust port of an internal combustion engine at its one end and fitted into the casing from a hole provided therein for communication with one of the chambers at its other end, and an exhaust outlet passage communicating another one of the chambers to the atmosphere. The internal end of the exhaust inlet tube and an opposing casing wall are joined by a threaded fastener while the exhaust inlet tube is provided with an annular shoulder surface which fits into the hole of the casing in an air tight fashion, so that the mounting of the muffler can be accomplished simply by fitting the casing of the muffler onto the exhaust inlet tube which is typically attached to a cylinder head of an internal combustion engine in advance and tightening the threaded fastener.

Abstract: An interlinking control device in a tractor-mounted working machine having an engine with a governor, a braking mechanism for braking wheels, and a clutch operatively coupled between the engine and the wheels. The braking mechanism and the clutch are operated respectively by first and second control systems, which have ends coupled to a single human-operated swingable member. The clutch starts being disengaged when the swingable member starts swinging and is completely disengaged when the swingable member is positioned intermediately on a path of swingng movement thereof. The braking mechanism produces a maximum braking force when the swingable member reaches a terminal end of the path of swinging movement thereof.

Abstract: A composite sound and heat insulating board comprising a base layer consisting of a compacted mat of filaments, and an additional layer of a material which differs in hardness than the compacted mat, wherein one surface of the base layer is securely attached to one surface of the additional layer. The compacted fiber mat may be composed of filaments of an organic composition, filaments of an inorganic composition, or partially of filaments of an organic composition and partially of filaments of an inorganic composition. The additional layer of the composite board is constructed of a naturally occurring or synthetic resin such as, for example, a relatively hard thermosetting or thermoplastic synthetic resin, or a relatively soft material which is lower in hardness than the compacted fiber mat. The composite board is advantageous when used in association with a source of heat and noise such as, for example, an internal combustion engine of a power driven vehicle.

Abstract: A heat and sound insulation device including a heat and sound insulation material composed of a laminated body comprising elongate glass fibers and ceramic fibers mixed therewith, the heat and sound insulation material having an inner surface entirely exposed in an exhaust passage for increased heat insulation, sound insulation, and durability.

Abstract: A silencer for an internal combustion engine includes a main silencer having an axially movable tubular member located therein which is movable from a first position in which it constitutes an extension of an inlet to the main silencer and a second position in which it is spaced from the inlet for exhaust gases entering the silencer, thus permitting the exhaust gases to flow directly into the main silencer.