Abstract: A swing angle measuring apparatus generates feedback signals for closed loop regulation of a load swinging motion in operation of a crane. The swing angle measuring apparatus measures two-dimensional swing angles, and includes a rope fixed to a hoisting device, two laser displacement sensors, laser reflecting plates, and a rectangular box attached to a hoisting device. Two steel reflecting plates are installed on the periphery of the fixed rope. Two laser displacement sensors are installed in a rectangular box such that the heading of the sensors are configured to perpendicularly intersect the faces of the laser reflecting plates. The configuration of the displacement sensors and the reflecting plates can be reversed. The rectangular box is attached to the hoisting device, and the laser reflecting plates are placed at an offset distance away from the face of the laser displacement sensors, at which a sensor signal of 0 volts is obtained.

Abstract: An apparatus for polish-grinding a semiconductor wafer which assuredly removes contaminant dusts from the polished wafer includes a grinding device for polishing a surface of the wafer. The grinding device has a chuck table on which the wafer is laid, a grinding wheel for grindingly polishing the wafer, and means for supplying water to the wafer. The means for supplying water provides water to region of contact between the grinding wheel and the wafer. The apparatus also includes a cleaning device for cleaning any remaining dust on the wafer, having a spin chuck table for rotating the polished wafer, means for supplying a detergent to the polished wafer. The means for supplying the detergent injects the detergent on the surfaces of the polished wafer. The apparatus also includes a controller for controlling the grinding device and the cleaning device.