Abstract: A diaphragm pump includes a low pressure side diaphragm forming a part of a pulsation operating chamber, a high pressure side diaphragm forming a part of a pump chamber, and a connecting portion connecting the low pressure side diaphragm and the high pressure side diaphragm. The high pressure side diaphragm operates in conjunction with the low pressure side diaphragm by being connected to the low pressure side diaphragm by the connecting portion. An area of a high pressure side operating portion of the high pressure side diaphragm is smaller than an area of a low pressure side operating portion of the low pressure side diaphragm.

Abstract: A fuel pressurization device configured to pressure-feed starting fuel to an engine. The fuel pressurization device includes a fuel chamber forming portion including a fuel chamber to which the fuel is supplied from the pump and whose internal volume is variable, and a spring configured to bias the fuel chamber forming portion so as to reduce the volume of the fuel chamber and to pressure-feed the fuel in the fuel chamber.

Abstract: A choke valve structure includes an air cleaner body having a suction pipe portion provided on an end wall, a choke valve having a valve body allowed to adhere to a sealing surface formed around an opening, and a movement mechanism configured to move the choke valve along a direction parallel to the sealing surface such that the valve body moves in closing and opening directions. A blowing back prevention plate disposed on an axial line of the suction pipe portion to face the opening is provided integrally with the air cleaner body. A protrusion, allowed to come into contact with the blowing back prevention plate when the valve body moves in the closing direction, is provided on the valve body. The valve body is pressed against the sealing surface to adhere thereto when the protrusion conies into contact with the blowing back prevention plate.

Abstract: A choke valve structure includes an air cleaner body having a suction pipe portion provided on an end wall, a choke valve having a valve body allowed to adhere to a sealing surface formed around an opening, and a movement mechanism configured to move the choke valve along a direction parallel to the sealing surface such that the valve body moves in closing and opening directions. A blowing back prevention plate disposed on an axial line of the suction pipe portion to face the opening is provided integrally with the air cleaner body. A protrusion, allowed to come into contact with the blowing back prevention plate when the valve body moves in the closing direction, is provided on the valve body. The valve body is pressed against the sealing surface to adhere thereto when the protrusion conies into contact with the blowing back prevention plate.

Abstract: In a chain saw, the tension of a saw chain attached around the outer edge of a guiding bar can be adjusted appropriately by adjusting the force transmitted to a connecting unit during operation of a hand guard. Thus, the saw chain 6 can be easily strained at great tension without use of a strong coil spring.

Abstract: A chain saw an operator can easily strain a saw chain is provided. In the chain saw 1, the tension of a saw chain 6 attached around the outer edge of a guiding bar 4 can be adjusted appropriately by adjusting the force transmitted to a connecting unit 24 during operation of a hand guard 40. Thus, the saw chain 6 can be easily strained at great tension without use of a strong coil spring.

Abstract: A backpack type irrigation apparatus having a backpack frame, a pump attached to the frame, an internal combustion engine serving as a driving source for the pump, and a discharge hose connected to a discharge port of the pump. A throttle lever of the internal combustion engine may be attached to the backpack frame. With this arrangement, the pump and the engine can be moved together with the discharge hose, and also a suction hose can be moved. Accordingly, the water-supply range is enlarged. Also, the discharge amount can be adjusted by operating the throttle lever while driving the pump.

Abstract: Provided are starters for securely starting an internal combustion engine. The starters have a reel rotatably mounted in a case, a starting rope wound on the reel, a rotor rotatably mounted in the case, a spring for storing energy with rotation of the rotor in a predetermined direction, an engaging mechanism for engaging the reel with the rotor with pullout of the starting rope to transmit a torque of the reel to the rotor to store energy in the spring, and an engagement release mechanism for releasing the engagement between the reel and the rotor at the start of rewinding of the starting rope onto the reel to rotate the rotor by a restoring force of the spring. This arrangement permits the internal combustion engine to be started readily and securely.

Abstract: Apparatuses and methods for controlling HC in exhaust, with Schnuerle type 2-cycle engine. When piston reaches near dead center point, the ends of the channel at the bottom end of piston reach from outlet ports and No. 1 transfer ports, and exhaust gas from outlet ports moves to the top of No. 1 transfer ports, and there a specified amount is kept. With scavenging, the pair of No. 1 transfer ports open first to combustion chamber, and the exhaust gas is introduced to combustion chamber, after which the pair of No. 2 transfer ports is opened to combustion chamber, and the air-fuel mixture is introduced to combustion chamber. Exhaust gas first introduced from No. 1 transfer ports creates a reverse eddy, and there is scavenging within combustion chamber, purging gas as it is into exhaust port. Air-fuel mixture introduced later from No. 2 transfer ports is limited in purging, and is kept in combustion chamber.

Abstract: Apparatuses and methods for reducing hydrocarbons in two-stroke engine exhaust. When a piston is close to top dead center, a groove in the lower end region of the piston confronts an exhaust port and first scavenging ports, respectively, and exhaust gas from the exhaust port is directed to the first scavenging ports. During a scavenging stroke, the first scavenging ports open first to a combustion chamber and exhaust gas is introduced to the combustion chamber, and a second pair of scavenging ports then opens to the combustion chamber and introduces a fuel-containing gas to the combustion chamber. When crankcase pressure reaches 142 Pa or higher, a relief valve opens and maintains the maximum pressure at 142 kPa or lower. Thus, blending in the combustion chamber of the exhaust gas from the first scavenging ports and the fuel-containing gas from the second scavenging ports is suppressed, and short-circuiting of the fuel component to the exhaust port is suppressed.

Abstract: Provided are starters for securely starting an internal combustion engine. The starters have a reel rotatably mounted in a case, a starting rope wound on the reel, a rotor rotatably mounted in the case, a spring for storing energy with rotation of the rotor in a predetermined direction, an engaging mechanism for engaging the reel with the rotor with pullout of the starting rope to transmit a torque of the reel to the rotor to store energy in the spring, and an engagement release mechanism for releasing the engagement between the reel and the rotor at the start of rewinding of the starting rope onto the reel to rotate the rotor by a restoring force of the spring. This arrangement permits the internal combustion engine to be started readily and securely.

Abstract: A backpack type irrigation apparatus having a backpack frame, a pump attached to the frame, an internal combustion engine serving as a driving source for the pump, and a discharge hose connected to a discharge port of the pump. A throttle lever of the internal combustion engine may be attached to the backpack frame. With this arrangement, the pump and the engine can be moved together with the discharge hose, and also a suction hose can be moved. Accordingly, the water-supply range is enlarged. Also, the discharge amount can be adjusted by operating the throttle lever while driving the pump.

Abstract: A two-stroke cycle engine having an improvement of its power output while reducing total hydrocarbons in the exhaust gases. The two-stroke cycle engine comprises a crank chamber adapted to receive a fuel mixture through feed means and a combustion chamber in a cylinder. Scavenging ports are provided for communication between the combustion chamber and the crank chamber to transfer the fuel mixture from the crank chamber to the combustion chamber while a exhaust port is provided for exhausting the burned gases from the combustion chamber. Reciprocation of the piston results in increase or decrease in volume of the combustion chamber while opening or closing the exhaust port and the scavenging ports. Communication means are provided for communicating the exhaust port with the crank chamber via the scavenging ports to draw a portion of the burned gases from the exhaust port into the crank chamber when the piston is in its top dead center.

Abstract: Apparatuses and methods for reducing hydrocarbons in two-stroke engine exhaust. When a piston is close to top dead center, a groove in the lower end region of the piston confronts an exhaust port and first scavenging ports, respectively, and exhaust gas from the exhaust port is directed to the first scavenging ports. During a scavenging stroke, the first scavenging ports open first to a combustion chamber and exhaust gas is introduced to the combustion chamber, and a second pair of scavenging ports then opens to the combustion chamber and introduces a fuel-containing gas to the combustion chamber. When crankcase pressure reaches 142 Pa or higher, a relief valve opens and maintains the maximum pressure at 142 kPa or lower. Thus, blending in the combustion chamber of the exhaust gas from the first scavenging ports and the fuel-containing gas from the second scavenging ports is suppressed, and short-circuiting of the fuel component to the exhaust port is suppressed.

Abstract: Apparatuses and methods for controlling HC in exhaust, with Schnuerle type 2-cycle engine. When piston reaches near dead center point, the ends of the channel at the bottom end of piston reach from outlet ports and No. 1 transfer ports, and exhaust gas from outlet ports moves to the top of No. 1 transfer ports, and there a specified amount is kept. With scavenging, the pair of No. 1 transfer ports open first to combustion chamber, and the exhaust gas is introduced to combustion chamber, after which the pair of No. 2 transfer ports is opened to combustion chamber, and the air-fuel mixture is introduced to combustion chamber. Exhaust gas first introduced from No. 1 transfer ports creates a reverse eddy, and there is scavenging within combustion chamber, purging gas as it is into exhaust port. Air-fuel mixture introduced later from No. 2 transfer ports is limited in purging, and is kept in combustion chamber.

Abstract: A two-stroke cycle engine having an improvement of its power output while reducing total hydrocarbons in the exhaust gases. The two-stroke cycle engine comprises a crank chamber adapted to receive a fuel mixture through feed means and a combustion chamber in a cylinder. Scavenging ports are provided for communication between the combustion chamber and the crank chamber to transfer the fuel mixture from the crank chamber to the combustion chamber while a exhaust port is provided for exhausting the burned gases from the combustion chamber. Reciprocation of the piston results in increase or decrease in volume of the combustion chamber while opening or closing the exhaust port and the scavenging ports. Communication means are provided for communicating the exhaust port with the crank chamber via the scavenging ports to draw a portion of the burned gases from the exhaust port into the crank chamber when the piston is in its top dead center.