Abstract: First and second connecting portions 61a and 62a are arranged in parallel and relatively turnably connected to a rocker arm 36 and a movable support portion 62b of a second link arm 62 is placed nearer to an engine valve 19 than a fixed support portion 61b of a first link arm 61. This makes it possible to decrease the size of a valve operating system and ensure the follow-up ability of the opening/closing operation as well as to vary a lift amount of the engine valve continuously while maintaining the reliability and durability of drive means.

Abstract: An engine valve operating system is provided in which a rocker arm that swings by following a valve operating cam abuts against an engine valve via a hydraulic tappet, a receiving member (41) receiving the hydraulic tappet (12) being slidably fitted into the rocker arm (13), the hydraulic tappet (12) being fitted into the rocker arm (13), a restricting part (29) being provided so as to face the receiving member (41) from the side opposite to the hydraulic tappet (12), and an adjustment screw (44) for adjusting a clearance between the restricting part (29) and the receiving member (41) when the engine valve is in a valve-closed state being screwed into an engine main body (5) so that its position can be adjusted back-and-forth so as to abut against the receiving member (41) when the engine valve is closed.

Abstract: First and second connecting portions 61a and 62a are arranged in parallel and relatively turnably connected to a rocker arm 36 and a movable support portion 62b of a second link arm 62 is placed nearer to an engine valve 19 than a fixed support portion 61b of a first link arm 61. This makes it possible to decrease the size of a valve operating system and ensure the follow-up ability of the opening/closing operation as well as to vary a lift amount of the engine valve continuously while maintaining the reliability and durability of drive means.

Abstract: A valve-operating system for an internal combustion engine includes cam followers which have cam abutment portions abutting against valve-operating cams provided on a camshaft and which are swingably carried in an engine body and operatively connected to engine valves biased in a closing direction by a valve spring. The cam followers are biased in a direction of abutment of the cam abutment portions against the valve-operating cams by a resilient biasing means different from the valve spring. A resilient biasing means includes a pull rod connected at one end thereof to the cam follower, and a compression coil spring interposed between the other end of the pull rod and the engine body to pull the pull rod to bias the cam follower in a direction of abutment of the cam abutment portion against the valve-operating cam. Thus, the resilient biasing means is constructed to be compact, leading to an increase in degree of freedom of the design of the structure of the valve-operating system.

Abstract: A drive of a variable valve lift mechanism for driving a control shaft controlling a variable valve lift mechanism provided between an engine valve and an engine valve operating cam in order to change lift amount of the engine valve, comprises: a rotational force generating actuator; power conversion means for converting a rotational force of the rotational force generating actuator into a pivoting force of the control shaft; and a casing containing the power conversion means with the rotational force generating actuator coupled to an outer face of the casing. One end of the control shaft protrudes outward from one side of an engine body. The casing into which one end of the control shaft is inserted is attached to the one side of the engine body through fixing means which can be repeatedly attached and detached. Thus, it is possible to avoid the engine body from being complex and improve maintainability.

Abstract: In an internal combustion engine including a valve actuating mechanism, a vibration control member made of vibration control alloy is interposed in a path of vibration transmission between a camshaft and a cylinder head. The vibration control alloy has a vibration isolation capability comparable to that of rubber, but provides a durability and a resistance to degradation comparable to those of metal and alloy that are typically used in internal combustion engines. Therefore, a desired vibration control can be achieved while ensuring a required reliability, durability and resistance to degradation. The present invention is particularly useful when the valve actuating mechanism is provided with a variable lift, variable timing or variable compression mechanism because such a variable mechanism increases the stress to the engine, and tends to cause more vibrations than a more conventional non-variable valve actuating mechanism.

Abstract: In an internal combustion engine including a valve actuating mechanism, a vibration control member made of vibration control alloy is interposed in a path of vibration transmission between a camshaft and a cylinder head. The vibration control alloy has a vibration isolation capability comparable to that of rubber, but provides a durability and a resistance to degradation comparable to those of metal and alloy that are typically used in internal combustion engines. Therefore, a desired vibration control can be achieved while ensuring a required reliability, durability and resistance to degradation. The present invention is particularly useful when the valve actuating mechanism is provided with a variable lift, variable timing or variable compression mechanism because such a variable mechanism increases the stress to the engine, and tends to cause more vibrations than a more conventional non-variable valve actuating mechanism.

Abstract: A drive of a variable valve lift mechanism for driving a control shaft controlling a variable valve lift mechanism provided between an engine valve and an engine valve operating cam in order to change lift amount of the engine valve, comprises: a rotational force generating actuator; power conversion means for converting a rotational force of the rotational force generating actuator into a pivoting force of the control shaft; and a casing containing the power conversion means with the rotational force generating actuator coupled to an outer face of the casing. One end of the control shaft protrudes outward from one side of an engine body. The casing into which one end of the control shaft is inserted is attached to the one side of the engine body through fixing means which can be repeatedly attached and detached. Thus, it is possible to avoid the engine body from being complex and improve maintainability.

Abstract: There is provided a double walled pipe having an inner pipe and an outer pipe which is movable relative to the inner pipe in a longitudinal direction of the inner pipe. Acting on only the outer pipe with a pipe jacking power makes it possible to bury the double walled pipe, without damaging the rear end of the inner pipe and also generating an internal stress on the inner pipe. Consequently, it is avoided such a situation that even in use pinholes, cracks, etc. occur on the inner pipe, and thus it is possible to expect an execution with higher reliability.

Abstract: There is provided a double walled pipe having an inner pipe and an outer pipe which is movable relative to the inner pipe in a longitudinal direction of the inner pipe. Acting on only the outer pipe with a pipe jacking power makes it possible to bury the double walled pipe, without damaging the rear end of the inner pipe and also generating an internal stress on the inner pipe. Consequently, it is avoided such a situation that even in use pinholes, cracks, etc. occur on the inner pipe, and thus it is possible to expect an execution with higher reliability.

Abstract: A buried pipe laying method of additionally coupling a new pipe with the extreme end of a buried pipe laid underground involves flatly deforming a cylindrical pipe having a pipe length smaller than the inside diameter of the buried pipe, conveying the deformed cylindrical pipe to the extreme end of the buried pipe laid underground through the interior thereof, and then returning the deformed shape of the cylindrical pipe to its original circular shape and coupling it with the extreme end of the buried pipe.

Abstract: There is provided a double walled pipe having an inner pipe and an outer pipe which is movable relative to the inner pipe in a longitudinal direction of the inner pipe. Acting on only the outer pipe with a pipe jacking power makes it possible to bury the double walled pipe, without damaging the rear end of the inner pipe and also generating an internal stress on the inner pipe. Consequently, it is avoided such a situation that even in use pinholes, cracks, etc. occur on the inner pipe, and thus it is possible to expect an execution with higher reliability.