Abstract: A method for manufacturing a multiple-wall synthetic-resin case having vertical multiple walls. The case is manufactured by integrating both upper and lower halves into one piece by jointing together; more specifically, each of the vertical walls is manufactured by jointing the upper wall formed in the upper half to the corresponding lower wall formed in the lower half. The jointing portions of the respective pairs of mating vertical walls are provided with different elevations so that they form their individual closed loops on the respective planes of elevations different from each other, conductive wire is inserted between the jointing surfaces of the upper and lower wall halves at each mating portion and apply high-frequency-heating to the conductive wire for welding the jointing surfaces.

Abstract: A drive device for coolant pumps having a pump shaft, a boss having a bore in which the pump shaft is rotatably disposed and a driven gear made from synthetic resin to transmit the rotational power from the crankshaft to the impeller to move the coolant into circulation through the coolant jacket for engine cooling, is disclosed which comprises a pin, fixedly implanted in radial pattern in the circumference of the pump shaft, a couple of radially extending grooves outwardly from the center of the driven gear bore in that side of the driven gear facing the impeller to receive therein fittingly the pin, respectively, and a washer mounted about the pump shaft between the front end face of the bore and the pin so as to prevent the pump shaft from falling off from its bore. When the driven gear is driven by the crankshaft, the pin closely fitted in the grooves transmits the torque to the pump shaft, without any slip.

Abstract: A muffler for work vehicle V-type internal combustion engines is disclosed, which is mounted in a horizontal sideway position, with its axis placed perpendicularly with the longitudinal vehicle axis, kept a proper distance from the chassis or vehicle body so that it is disposed in full exposure to the atmosphere for proper cooling. A pair of spaced inlet ports are provided in the muffler, at locations adjacent to opposite ends thereof for receiving the exhaust gases from the engine through a pair of parallely extending, parallel exhaust pipes directly interconnected between the combustion chambers of the two cylinders and the muffler inlet ports, without using the conventional intermediate flexible corrugated connectors.

Abstract: A valve gear adapted for a four-cycle engine. Provided are a groove having such a shape folding around a crank shaft with an intersection as to return back to a starting point in two turns, a cam formed on top faces of both banks of aforesaid groove, a tappet arm projecting sideways from a tappet and elastically engaged with aforesaid cam, and a slider supported by aforesaid tappet arm and slidably fitted into aforesaid groove, and aforesaid tappet arm is guided by aforesaid slider to be given a lift by aforesaid cam provided on the outer circumference of the crank shaft.

Abstract: A lubricating device for an overhead valve engine having a rocker arm chamber provided with a valve gear, a crank chamber provided with a valve driving gear, and valve drive push rods disposed between the valve gear and the valve driving gear. Provided are paths respectively communicating aforesaid crank chamber to aforesaid rocker arm chamber, aforesaid rocker arm chamber to aforesaid push rod chamber, and the bottom of aforesaid push rod chamber to aforesaid crank chamber through a bearing portion on a power takeoff side, or the bottom of aforesaid push rod chamber is communicated to aforesaid bearing portion of aforesaid power takeoff side with an outlet for breather gas in aforesaid push rod chamber.

Abstract: A cooling system for V-type engine comprises rows of left and right cylinders arranged in V-type and having coolant jackets, respectively. A coolant pump having a pump shaft parallel to a crankshaft is arranged with a V-bank and at a place away from each cylinder in an axial direction of said crankshaft, and coolant jacket inlets are provided on the side of the coolant pump of each cylinder. Alternately, the coolant jacket inlets of the cylinders are opened respectively at one end face in the direction of the crankshaft of a crankcase-forming member, and a distributing exit passage is defined by joint faces of said crankcase-forming member, a pump casing and a pump casing cover respectively.

Abstract: Disclosed is a valve gear for use in a four-cycle engine which eliminates the necessity of providing a cam shaft. In the valve gear, a guide or guides, each of which is shaped like a closed curve making two rounds of a crank shaft with one intersection on the way, are provided. An air-intake valve and/or exhaust valve are controlled in accordance with the movement of a slider member sliding along the guide or guides.

Abstract: An improved horizontal type radiator is disclosed in which the top wall of a header tank, into which a bank of radiator tubes are opened, is externally raised into an annular bulge formed to encircle an upper pipe hole bored in the wall through which a water filling pipe is inserted into the header tank forming an annular space about the inserted lower end of the pipe. Also, the bottom wall of the header tank is outwardly bulged into an annular bulge formed to encircle a lower pipe hole bored in the wall through which a water passage pipe is inserted into the header tank forming an annular space about the inserted end portion of the water passage pipe. With this arrangement, in operation when the water flows from the radiator tubes into the header tank, the water has limited chance of entraining air within the header tank, since the upper annular space in which air may possibly be entrained offers only a minimum contact surface of air with the water.

Abstract: A valve gear for a four-cycle engine having an overhung crankshaft connecting with an output shaft, wherein a guide portion having such a shape folding the output shaft as to return back to a starting point in two turns, is formed on the output shaft, and an interlocking mechanism guided by the guide portion is provided to open the valves for the four-cycle engine. It is preferable that the guide portion is formed as cam face displacing the interlocking mechanism. The guide portion can be formed on a block other than the output shaft for easy machining and also for adjustable valve timing.

Abstract: A valve gear adapted for the four-cycle engine comprises guide portions(s) which is formed on the end surface(s) of crankweb(s) of a crankshaft, and has such a shape folding around the crankshaft with an intersection as to return back to a starting point in two turns; and two interlocking mechanisms provided between the guide portion(s) and the intake and exhaust valves in the engine to open the valves by being guided by the guide portion(s).

Abstract: A 4-cycle engine including a crankshaft connected to a piston and supported at opposite ends by a crankcase for rotation. The crankshaft is formed at one of its two output shaft sections with a groove extending peripherally along the outer peripheral surface of one output shaft section substantially in the form of a endless loop having a cross point. A plurality of followers engaged in the groove have their movements transmitted, through respective linkages, to an exhaust valve and a suction valve respectively. A governor device is located at the other output shaft section and operative to actuate an engine rpm. controller depending on the speed of rotation of the crankshaft.

Abstract: A compression release device for side-valve and overhead-valve internal combustion engines is disclosed, which takes advantages of the difference in thermal expansion of different materials to control the valve opening depending on the condition of ambient temperature. A first material of comparatively higher linear expansion coefficient is used for the cylinders and cylinder head, while a second material of comparatively lower expansion coefficient for the push rods and tappets for either or both of the intake and exhaust valves, with the valve or valves being set to take a valve lift enough to cause the valve, upon compression stroke, to remain properly slightly open at cold start to ease crankshaft rotation, while stay fully shut, as a result of the cylinders and cylinder head having undergone a greater degree of thermal expansion than the push rods and tappets, when the engine gets warmed up.

Abstract: A V-type internal combustion engine in which cylinders each including a cylinder skirt portion projecting into a crankcase are arranged in a V-shape, a governor device is disposed within the crankcase, central axes of the cylinders are offset from each other in an axial direction along a crankshaft supported in the crankcase, and a rotational speed transmission system for transmitting a rotational speed of a governor gear to a governor lever shaft is engages a rearward side of the cylinder skirt portion of a cylinder spaced forward from a rearward most cylinder as viewed among the crankshaft central axis. A single intake manifold is adapted to bridge cylinder heads in a V-bank defined between the cylinders. A carbureter is in fluid communication with the intake manifold. One end of the governor lever shaft is disposed in the V-bank. An intake control for controlling the carbureter in cooperation with one end of the lever shaft is disposed in the vicinity of the carbureter.

Abstract: A valve gear adapted for a four-cycle engine having a guide portion formed on the outer surface of an output shaft connected to a crankshaft, and of such a shape folding around the output shaft as to return back to a starting point in two turns, and having interlocking mechanisms provided with portions engaging with the guide portion and moved by the rotation of the crankshaft to open valves. The guide portion, only one in number, is provided on the output shaft connected to the crankshaft, and the interlocking mechanisms for driving intake and exhaust valves are disposed substantially opposite to each other across the output shaft as to engage with aforesaid single guide portion.

Abstract: A valve system for the overhead valve type four-cycle engine disposing the intake and exhaust valves substantially symmetrically to each other with respect to the cylinder center line, wherein the valve stems are so tilted in the cylinder head that the valve bodies are in juxtaposition close to the cylinder center line. Guide cams are disposed around the circumferential surface of the crank shaft, respectively return back to the same starting point while making two turns, and respectively have one projection in the course of the turn, for driving the intake and exhaust valves. Between the guide cams and the respective intake and exhaust valve, a sliding piece, push rod and rocker arm are provided, and the projection on each of aforesaid cam is designed to be placed at such a position as to engage with the sliding piece to the opening timing of the intake and exhaust valves.

Abstract: Disclosed is a valve gear for use in a four-cycle engine which eliminates the necessity of providing a cam shaft. In the valve gear, a guide or guides, each of which is shaped like a closed curve making two rounds of a crank shaft with one intersection on the way, are provided. An air-intake valve and/or exhaust valve are controlled in accordance with the movement of a slider member sliding along the guide or guides.

Abstract: A liquid-cooled engine of the vertical shaft type has a row of left and right side cylinders arranged in a V-shape as viewed from the above. The cooling water jackets of the left and right side cylinders are connected to each other at the highest ends of the cooling water jackets at the sides of cylinder heads of the cylinders through a communicating passage, a thermostat chamber is provided at the highest end of the cooling water jacket of one of the cylinder heads which is located lower than the other cylinder head, the communicating passage being connected at its one end to the thermostat chamber.

Abstract: An overhead valve engine including a bore for receiving a push rod for actuating a suction valve and a bore for receiving a push rod for actuating a discharge valve. Blowby gas is introduced into one of the bores from a crank chamber and supplied to the other bore via a rocker arm chamber to lubricate the push rods with oil mist in the blowby gas. After lubricating the push rods, the blowby gas is released via the breather gas from the engine.

Abstract: A vertical shaft V-type engine having a vertical crankshaft and a pair of right and left hand cylinders arranged in V-shape, the engine comprising a carburetor arranged within a V-bank defined between both cylinders and an air cleaner arranged upwardly of the carburetor. The engine is also provided with an air fan and the air cleaner is arranged adjacent to a fan housing of the air fan.

Abstract: A throttle control device for the general purpose engine having a throttle lever for moving a throttle valve of the carburetor and a choke lever for moving a choke valve of the carburetor. The choke lever and the throttle lever are moved together with each other in a predetermined timing. A control panel pivotally supporting the throttle lever and the choke lever is swingable in a predetermined angle range.