Abstract: A coaxial-type carbon dioxide gas laser includes an oscillator comprising a gas inlet for introducing gas into a discharge tube through a gas supply chamber having a hollow cylindrical body which serves to disturb the gas flow and orientate the gas toward the discharge tube via a space defined between the discharge tube and the hollow cylindrical body. The gas which has been subjected to an electrical discharge is drawn out of the discharge tube through a chamber and a gas outlet connected therewith. A pair of anode and cathode electrodes are disposed adjacent to the ends of the discharge tube. One of the electrodes is mounted on the gas supply chamber and is annular in shape. The gas supply chamber and the hollow cylindrical body jointly define a gap for passage therethrough of the gas fed from the gas inlet toward the discharge tube via the space. The space is large in cross section than the gap.

Abstract: Engine cooling system including a cooling water passage having cooling water jackets formed in the engine and a water pump for circulating cooling water through the water passage. A driving motor is provided for driving the water pump and a control circuit for the motor receives an engine speed signal so that the speed of the water pump is decreased to a predetermined low level when the engine temperature is low so that the engine can be warmed up rapidly while maintaining a cooling water circulation for preventing local overheating of the engine.

Abstract: An improved ignition arrangement for internal combustion engines includes, besides an ignition plug normally employed, another ignition plug provided on a guide surface confronting an exhaust port side of a guide wall for prevention of knocking by properly determining ignition time, with a simultaneous improvement of combustibility.

Abstract: Engine cooling system including cooling water passages having cooling water jackets formed respectively in the hot temperature portion and the cold temperature portion of the engine and water pumps for circulating cooling water through the water passages. Driving motors are provided for driving the water pumps and a control circuit for the motors receives an engine speed signal so that the water pump for the water passage to the cold temperature portion of the engine is stopped when the engine temperature is low so that the engine can be warmed up rapidly while maintaining a cooling water circulation through the water passage in the hot temperature portion for preventing local overheating of the engine.

Abstract: An apex seal of a rotary piston engine comprising a sealing groove formed in each apex portion of the rotor, a sealing piece and a support piece disposed in the sealing groove with a superposed relationship. A corner seal at each end of the apex seal including a corner seal member formed with a longitudinally extending slit for receiving an adjacent end of the apex seal pieces. The slit in the corner seal member is generally wider than the sealing groove of the apex seal but has a minimum width portion that is narrower than the sealing groove. The minimum width slit portion is disposed against only one of the sealing and support pieces of the apex seal so that the sideward movement of the other piece is not disturbed by the corner seal member.

Abstract: A cross-flow type internal combustion engine having an exhaust gas recirculating passage formed in the cylinder head. The passage is located adjacent to cooling water jackets so that the gas in the passage is cooled by the water in the jackets. The passage is formed with an expansion chamber which is also located adjacent to the cooling water jackets and the intake ports. Due to the cooling effect in the passage, water content in the recirculated gas is condensed and separated from the gas. Further, the gas flow speed is decreased in the expansion chamber so that carbon particles in the recirculated gas can be separated therefrom.

Abstract: A rotary piston engine including a lubricating system having an oil passage extending axially through an eccentric shaft for supplying lubricating oil from an oil pump to bearing portions. A pressure regulator valve is provided in said oil passage in the eccentric shaft so that the oil pressure as regulated by the regulator valve is not affected by the centrifugal force which may be produced in the oil passing through a radial passage between the oil pump and the oil passage in the eccentric shaft. The regulator valve may include a temperature sensor which is responsive to the surrounding temperature.

Abstract: Disclosed is a device for automatically correcting dynamic-unbalance of a rotor. The device utilizes a laser beam which moves in synchronism with movement of a detected unbalanced position on the rotor to burn off portions of the rotor until a balanced condition is achieved.

Abstract: Rotary piston engine includes a substantially triangular rotor formed with flank cooling oil passages located behind flanks of the rotor. The rotor further has coolant oil passages behind the oil seals at the opposite side surfaces thereof. The flank cooling oil passages are supplied with cooling oil only when the rotor temperature or engine speed is beyond a predetermined value, while the oil seal cooling passages are always supplied with cooling oil so that the rotor flanks can be maintained at a high temperature while preventing the oil seals from being excessively heated.

Abstract: A process for excavating and constructing a tunnel, and an excavating device are disclosed. This process is directed to excavating and constructing a tunnel under a railway or a road on a banking or on level land in the direction transverse to the railway or road. In this process, pits are dug on the opposite sides of the railway, and then an excavator digs into the wall of a pit on one side so as to go out of the wall of the other pit through the ground left therebetween. In this respect, a hollow casing unit of a box shape is coupled to the rear end of the excavator equipped with a screw conveyor. As the excavator advances or digs forwards a given distance, another casing unit is in turn coupled to the rear end of the preceding casing unit, and then such a step is repeated, until the excavator goes out of the wall of another pit. In this manner, the excavator further digs into the wall of one pit in the position adjacent to the preceding run of casing units.

Abstract: A process for excavating and constructing a tunnel, and an excavating device are disclosed. This process is directed to excavating and constructing a tunnel under a railway or a road on a bank or on level land in the direction transverse to the railway or road. In this process, pits are dug on the opposite sides of the railway, and then an excavator digs into the wall of a pit on one side so as to go out of the wall of the other pit through the ground left therebetween. In this respect, a hollow casing unit of a box shape is coupled to the rear end of the excavator equipped with a screw conveyor. As the excavator advances or digs forward a given distance, another casing unit is in turn coupled to the rear end of the preceding casing unit, and then such a step is repeated, until the excavator goes out of the wall of another pit. In this manner, the excavator further digs into the wall of one pit in the position adjacent to the preceding run of casing units.

Abstract: A housing structure for a rotary piston internal combustion engine comprises at least one peripheral casing having an epitrochoidal surface formed therein, and a pair of end walls connected to each other with the peripheral casing situated therebetween. Portions of the end walls and peripheral casing which are simultaneously exposed to one of the working chambers in which the expansion stroke is taking place, that is, the expansion chamber, has therein respective heat insulating layers so as to substantially avoid a possible reduction of the temperature of the exhaust gas staying within the expansion chamber.

Abstract: An automobile combustion engine having at least one exhaust port is provided with a tubular insert within an engine casing. This tubular insert is accommodated within an exhaust passage leading from at least one combustion chamber towards the exhaust port, and is held in position by the interposition of a heat insulating member made of heat insulating material having a lower thermal conductivity than that of material of the engine casing and/or the tubular insert. Heat transfer from the tubular insert to the engine casing is minimized by the interposition of the heat insulating member thereby avoiding a possible reduction of the temperature of an exhaust gas flowing through the tubular insert towards a subsequent process station.