Abstract: An internal combustion engine fuel injection control apparatus is disclosed in which a basic fuel injection signal for light load is calculated as a function of the manifold pressure when the engine is operating with a light load, and a basic fuel injection signal for heavy load is obtained with the revolution number and the throttle valve position as the parameters when the engine is operating with a heavy load. The engine load condition (light or heavy) is decided in dependence upon the throttle valve position or the manifold pressure. The circuit employed for switch-over from a heavy load to a light load or vice versa preferably has a hysteresis characteristic.

Abstract: A feed safety apparatus for a movable member slidably supported on a stationary bed of a machine tool. A feed device moves the movable member at various speeds. A hydraulic cylinder is fixedly mounted on the movable member and includes a piston slidably received therein. A reference plate member is secured to the bed and operatively connected to the piston for permitting bodily movement of the hydraulic cylinder and the piston within a predetermined distance, but restraining movement of the piston beyond the predetermined distance to cause relative movement between the hydraulic cylinder and the piston. A fluid flow regulating device is disposed between the pair of cylinder chambers of the hydraulic cylinder for restrictively controlling relative movement between the hydraulic cylinder and the piston.

Abstract: A grinding machine wherein a CBN grinding wheel is rotatably carried to grind a workpiece on a work support device and is provided with a re-truing device, in addition to a truing and dressing device rotatably carrying a truing roll and a counter roll. When a truing and dressing instruction is generated, the CBN wheel is first trued with the truing roll, is then dressed by free abrasive grain supplied between itself and the counter roll and is finally re-trued with a diamond impregnated truing bar carried on the re-truing device. A re-truing infeed of the truing bar against the CBN wheel is considerably less than a truing infeed of the CBN wheel against the truing roll, and therefore the re-truing is effected on cutting edges of the wheel abrasive grain damaged by the free abrasive grain in dressing, whereby the cutting edges are made somewhat dull.