Abstract: A copper-based alloy excellent in dezincing resistance comprises, in percentage by weight, Cu: 57-69%, Sn: 0.3-3%, Si: 0.02-1.5%, Bi: 0.5-3%, and Pb: not more than 0.2%, where the ratio of Si/Sn expressed in weight percentage is in the range of 0.05-1 and apparent zinc content as defined by the following formula is in the range of more than 39-50 wt. %, and the balance of unavoidable impurities: Apparent Zn content=[(Zn %+2.0×Sn %+10.0×Si %)/(Cu %+Zn %+2.0×Sn %+10.0×Si %)]×100. Despite the fact that contains no added environment-unfriendly Pb, the alloy exhibits enhanced cuttability, together with excellent forgeability, dezincing resistance and hot forgeability.

Abstract: A copper alloy having an excellent corrosion cracking resistance and an excellent dezincing resistance consists of: 58 to 66 wt % of copper (Cu); 0.1 to 0.8 wt % of Sn; 0.01 to 0.5 wt % of Si; at least one of 0.3 to 3.5 wt % of lead (Pb), 0.3 to 3.0 wt % of bismuth (Bi), 0.02 to 0.15 wt % of phosphorus (P), 0.02 to 3.0 wt % of nickel (Ni) and 0.02 to 0.6 wt % of iron (Fe) if necessary; and the balance being zinc (Zn) and unavoidable impurities, wherein the proportion of an alpha phase is 80 vol % or more. The apparent content of zinc (Zn) in the copper alloy is in the range of from 34 to 39 wt %.

Abstract: A copper-based alloy excellent in dezincing resistance comprises, in percentage by weight, Cu: 57-69%, Sn: 0.3-3%, Si: 0.02-1.5%, Bi: 0.5-3%, and Pb: not more than 0.2%, where the ratio of Si/Sn expressed in weight percentage is in the range of 0.05-1 and apparent zinc content as defined by the following formula is in the range of more than 39-50 wt. %, and the balance of unavoidable impurities: Apparent Zn content=[(Zn %+2.0×Sn %+10.0×Si %)/(Cu %+Zn %+2.0×Sn %+10.0×Si %)]×100. Despite the fact that contains no added environment-unfriendly Pb, the alloy exhibits enhanced cuttability, together with excellent forgeability, dezincing resistance and hot forgeability.

Abstract: A radiator (12a) and an oil cooler (12b) are disposed separately from an engine (11) of a construction machine and cooled by a cooling fan (15). The oil cooler (12b) is located downstream from the radiator (12a) with respect to the air flow generated when the cooling fan (15) is driven in reverse. A hydraulic motor (32) is adapted to be controlled by a directional control solenoid valve (34) of a fan driving circuit (31) so that the cooling fan (15) may be stopped, rotated forward or rotated in reverse accordingly. The directional control solenoid valve (34) is adapted to be automatically switched by a control device (41) having temperature sensors (44), (45), (46).

Abstract: Each attachment for a hydraulically actuated device includes a digitally coded connector which informs a control device about its identity. The control device includes a library which relates the digitally coded identity with fluid parameters of pressure and flow rate required for operation of the hydraulically operated device. The control device outputs signals which control the accelerator of an engine, and also controls pump operations to establish the fluid parameters appropriate for the hydraulically actuated device. When a second device is actuated simultaneously with the original device, the control device automatically compensates with adjusted fluid parameters to permit optimum operation of both devices at the same time.

Abstract: An apparatus for controlling the lifting operation comprising an operation mode selection switch which is selectively set to an ordinary operation mode or to a lifting operation mode and a hydraulic circuit isolating means. The hydraulic circuit isolating means isolates the hydraulic circuit into a running drive hydraulic circuit which feeds the pressurized fluid of one of the variable-capacity hydraulic pumps to the actuators of the running apparatuses when the operation mode selection switch is set to the lifting operation mode and a hydraulic circuit for driving the apparatus on the side of the turning body, which feeds the pressurized fluid of the other variable-capacity hydraulic pump to the actuators other than those of the running apparatuses.