Abstract: An operation control lever unit for regulating power of an engine of an engine-powered working machine has a handle case attached to a support rod connected at one end to the engine and at the other end to a working tool, a throttle lever pivotally mounted to the handle case for controlling a throttle mechanism to regulate the engine speed, and a brake release lever pivotally mounted to the handle case in diametrically opposite relation to the throttle lever for releasing a brake mechanism associated with the engine. This arrangement enables the operator to manipulate the throttle lever using at least one finger excluding the thumb of its one hand and to depress the brake release lever with a palm of the same hand while maintaining a grip on the handle case.

Abstract: A bush cutting machine comprises a clutch case attached to a front part of an engine, an operation rod extending forwardly from the clutch case and having a brake lever, a cutting blade provided at a distal end of the operation rod, and a transmission shaft passing through the operation rod for transmitting drive power to the cutting blade. A brake drum is housed in the clutch case for braking the rotation of the cutting blade. A brake arm is swingably attached to a front wall of the clutch case closely to the brake drum. The brake arm carries at one end thereof a brake shoe for press contacting an outer peripheral surface of the brake drum. A brake wire is mounted between the brake lever and brake arm. The brake wire is disposed to extend along either external surface of the operation rod.

Abstract: A spark arrester includes a buffer plate against which exhaust gases discharged from the outlet end of a tail pipe strike directly. Upon impingement on the buffer plate, the exhaust gases become turbulent or agitated whereupon temperature distribution of the exhaust gases is made uniform. The buffer plate has a plurality of through-holes arranged to allow passage of the exhaust gases after the exhaust gases impinge against the buffer plate. After passing through the through-holes, the exhaust gases flow through a wire screen during which time sparks in the exhaust gases are caught by the wire screen. The exhaust gases are then guided downstream along a guide tube and finally released from an outlet end of the guide tube. A stream of exhaust gases discharged from the guide tube has only a limited length of high-temperature zone.

Abstract: An operation lever unit includes an operation handle attached to an operating rod of an engine-powered portable working machine. The operation handle is equipped with a throttle lever for regulating the power of an engine, a lock lever for holding the throttle lever in a desired position, and a secondary throttle adjustment lever for achieving a fine adjustment of the position of the throttle lever. To hold the throttle lever in the desired position, the throttle lever is forced against a portion of the operation handle by the action of a thrust cam mechanism disposed between the throttle lever and the lock lever. For achieving the fine adjustment of the throttle lever position, the secondary throttle adjustment lever is forced by a thumb of the operator to forcibly turn the throttle lever against a frictional force acting between the throttle lever and the handle portion.

Abstract: A particle of titanium compounds is in the form of a fine agglomerate comprising crystals of an alkaline-earth metal titanate represented by RTiO.sub.3 wherein R is an alkaline-earth metal and crystals of an alkali metal titanate represented by M.sub.2 Ti.sub.n O.sub.2n+1 wherein M is an alkali metal and n is an integer of 2 to 6, or these two kinds of crystals and crystals of titanium dioxide (TiO.sub.2), the two or three kinds of crystals being mingled together. A powder composed of such particles is produced by preparing a mixture from RO wherein R is an alkaline-earth metal or an alkaline-earth metal compound becoming RO when heated, M.sub.2 O wherein M is an alkali metal or an alkali metal compound becoming M.sub.2 O when heated, and TiO.sub.2 or a titanium compound becoming TiO.sub.2 when heated, in a ratio so that Z.gtoreq.X+mY wherein Z is the number of moles of TiO.sub.2, X is the number of moles of RO, Y is the number of moles of M.sub.

Abstract: Particles of titanium compounds each containing crystals of at least two kinds of alkaline earth metal titanate compounds of the perovskite type represented by RTiO.sub.3 wherein R is an alkaline earth metal which crystals are joined together or joined to crystals of TiO.sub.2. The friction material having added thereinto the powder of such particles of titanium compounds shows a high coefficient of friction and a low abrasive property to adjoining materials.

Abstract: A mulching mower is provided which is capable of cutting grasses finely without leaving uncut grasses and which is capable of discharging the cut grass clippings onto the cut grass path so as to be evenly dispersed. A pair of cutter blades are arranged to the right and to the left of the mulching mower in a cutter housing which opens downwardly. A guitar-shaped or figure 8 shaped enclosure wall hangs down from an under surface of an upper wall of the cutter housing to completely surround the periphery of the right and left cutter blades along tip end rotation loci of the blades at a slight distance therefrom. The enclosure wall is formed by side wall portions ar right and left outsides of the cutter housing and front and rear enclosure wall portions hang down from the under surface. The cutter blades rotate in opposite directions from each other so that tip ends of the cutter blades move from front to rear at right and left outsides, respectively, of the mulching mower.

Abstract: An aluminum alloy material of high strength and high toughness and a method for the production thereof are disclosed. The material of high strength and high toughness is produced by laterally changing the direction of extrusion of the aluminum alloy thereby imparting shear deformation productive of such strain intensity equals as an equivalent elongation of not less than 220%, preferably not less than 10,000% to the material in the process of extrusion and reducing the average particle diameter of the grains of a microstructure of the material to minute grains not exceeding 1 micron in diameter. The step of extrusion is carried out at a temperature not exceeding 300.degree. C., preferably not exceeding the recrystallization temperature of the alloy, and more preferably not exceeding the recovery temperature thereof.

Abstract: There is provided a compact and lightweight steam generator capable of efficiently and economically generating steam. An impeller is disposed in a housing. While the impeller is rotated by hot water poured inside the housing through a hot water inlet, the hot water is spread to generate steam inside the housing. By a ventilation fan to be operated in association with the impeller, the steam generated inside the housing is blown off into a shower room. The hot water poured inside the housing is discharged to the inside of a hot water reservoir through a discharge port. Steam generated inside the hot water reservoir, is drawn into the inside of the housing and then blown off into the shower room.

Abstract: A superplastic aluminum-based alloy material consisting of a matrix formed of aluminum or a supersaturated aluminum solid solution, whose average crystal grain size is 0.005 to 1 .mu.m, and particles made of a stable or metastable phase of various intermetallic compounds formed of the main alloying element (i.e., the matrix element) and the other alloying elements and/or of various intermetallic compounds formed of the other alloying elements and distributed evenly in the matrix, the particles having a mean particle size of 0.001 to 0.1 .mu.m. The superplastic aluminum-based alloy material is produced from a rapidly solidified material consisting of an amorphous phase, a microcrystalline phase or a mixed phase thereof by optionally heat treating at a prescribed temperature for a prescribed period of time and then subjecting to a single or combined thermo-mechanical treatment. The superplastic aluminum-based alloy material of the present invention is suited for to superplastic working.

Abstract: A superplastic aluminum-based alloy material consisting of a matrix formed of aluminum or a supersaturated aluminum solid solution, whose average crystal grain size is 0.005 to 1 .mu.m, and particles made of a stable or metastable phase of various intermetallic compounds formed of the main alloying element (i.e., the matrix element) and the other alloying elements and/or of various intermetallic compounds formed of the other alloying elements and distributed evenly in the matrix, the particles having a mean particle size of 0.001 to 0.1 .mu.m. The superplastic aluminum-based alloy material is produced from a rapidly solidified material consisting of an amorphous phase, a microcrystalline phase or a mixed phase thereof by optionally heat treating the material at a prescribed temperature for a prescribed period of time and then subjecting it to a single or combined thermomechanical treatment. The superplastic aluminum-based alloy material of the present invention is suited for superplastic working.

Abstract: A riding-type lawn mower has a cutter housing with a rear discharge slot defined in a rear wall thereof. The cutter housing accommodates a pair of cutter blades laterally spaced from each other and rotatable in a substantially horizontal plane. The cutter blades are arranged such that the cutter blade on the righthand side as viewed in a forward direction of the lawn mower body is rotatable clockwise as viewed in plan and the cutter blade on the lefthand side as viewed in the forward direction of the lawn mower body is rotatable counterclockwise as viewed in plan. The cutter housing has an upper wall that has a pair of laterally spaced portions raised upwardly and defining respective discharge passages in the cutter housing that lead to the rear discharge slot. Rotative power from a lawn mower engine is transmitted to the cutter blades by a belt-and-pulley mechanism disposed on a low flat portion defined between the raised portions of upper wall.

Abstract: An apparatus having stage means on which a substrate is placed, holding means for holding a mask formed with at least one mark, and exposing means for exposing the image of said at least one mark on the exposure surface of the substrate which is coated with photoresist includes displacing means for imparting relative displacement between the stage means and the holding means, control means for controlling the exposing means and the displacing means and executing first exposure and second exposure successively, the control means executing the first and the second exposure of exposing the image of said at least one mark on a plurality of predetermined areas of the exposure surface of the substrate placed on the stage means, and controlling the exposing means and the displacing means so that the amount of deviation between the position of the image of said at least one mark in each of the predetermined areas during the first exposure and the position of said image during the second exposure assumes a predetermin

Abstract: An aluminum alloy having excellent properties including extrusibility, forgeability and malleability, the alloy containing 4.0 to 12% of zinc, 0.3 to 5.0% of magnesium, and one or more elements selected from the rare earth elements, wherein the content of the selected element is in the range of 0.5 to 10.0%, and the balance being substantially aluminum and unavoidable impurities.