Abstract: A float device includes a drive motor provided inside a float hull, a plunger reciprocating along with rotation of the drive motor, an internal oil reservoir for housing an hydraulic oil therein, an externally-opened cylinder attached to the float hull, a buoyant force adjustment piston reciprocating in the cylinder along with exit/entry of the hydraulic oil, and a three-way valve having a first connection port connected to the plunger, a second connection port connected to the internal oil reservoir, and a third connection per connected to the cylinder, for switching the flow between the first connection port and the second connection ports and the flow between the first connection port and the third connection port.

Abstract: A float device includes a drive motor provided inside a float hull, a plunger reciprocating along with rotation of the drive motor, an internal oil reservoir for housing an hydraulic oil therein, an externally-opened cylinder attached to the float bull, a buoyant force adjustment piston reciprocating in the cylinder along with exit/entry of the hydraulic oil, and a three-way valve having a first connection port connected to the plunger, a second connection port connected to the internal oil reservoir, and a third connection per connected to the cylinder, for switching the flow between the first connection port and the second connection ports and the flow between the first connection port and the third connection port.

Abstract: To provide a winding mechanism and a trawling apparatus capable of eliminating an excessive tension or slack generated in a wire wound around a drum and keeping the tension or wire length of the wire constant. A winding mechanism with tension control function includes a reversibly rotatable liquid-pressure motor rotating a drum having a wire wound therearound, a liquid-pressure pump coupled directly with the liquid-pressure motor and supplying hydraulic oil, and an electric motor rotating to drive the liquid-pressure pump. The winding mechanism further includes a control unit controlling a torque of the electric motor based on a variation in load current of the electric motor and winding off or winding up the wire to keep the tension of the wire at a set value.

Abstract: A hoisting device can be small-sized and energy can be saved. A hoisting device 10 according to the present invention has a hoist 30 and a control unit 32. The hoist 30 rotates a drum 12 having a wire 14 wound thereon by an oil pressure motor 42 rotatable in normal and reverse directions. To the oil pressure motor 42, operating oil is supplied from an oil pressure pump 44. The oil pressure pump 44 is a two-way discharge fixed capacity type, and rotated by a servomotor 46. An acceleration/displacement transducer 34 in the control unit 32 finds a moving direction and a moving speed of a wire hanging point in the vertical direction from an output signal of an acceleration sensor 24.

Abstract: A hoisting device can be small-sized and energy can be saved. A hoisting device 10 according to the present invention has a hoist 30 and a control unit 32. The hoist 30 rotates a drum 12 having a wire 14 wound thereon by an oil pressure motor 42 rotatable in normal and reverse directions. To the oil pressure motor 42, operating oil is supplied from an oil pressure pump 44. The oil pressure pump 44 is a two-way discharge fixed capacity type, and rotated by a servomotor 46. An acceleration/displacement transducer 34 in the control unit 32 finds a moving direction and a moving speed of a wire hanging point in the vertical direction from an output signal of an acceleration sensor 24.

Abstract: A hoisting device can be small-sized and energy can be saved. A hoisting device 10 according to the present invention has a hoist 30 and a control unit 32. The hoist 30 rotates a drum 12 having a wire 14 wound thereon by an oil pressure motor 42 rotatable in normal and reverse directions. To the oil pressure motor 42, operating oil is supplied from an oil pressure pump 44. The oil pressure pump 44 is a two-way discharge fixed capacity type, and rotated by a servomotor 46. An acceleration/displacement transducer 34 in the control unit 32 finds a moving direction and a moving speed of a wire hanging point in the vertical direction from an output signal of an acceleration sensor 24.

Abstract: To provide a winding mechanism and a trawling apparatus capable of eliminating an excessive tension or slack generated in a wire wound around a drum and keeping the tension or wire length of the wire constant. A winding mechanism with tension control function includes a reversibly rotatable liquid-pressure motor rotating a drum having a wire wound therearound, a liquid-pressure pump coupled directly with the liquid-pressure motor and supplying hydraulic oil, and an electric motor rotating to drive the liquid-pressure pump. The winding mechanism further includes a control unit controlling a torque of the electric motor based on a variation in load current of the electric motor and winding off or winding up the wire to keep the tension of the wire at a set value.

Abstract: A hoisting device can be small-sized and energy can be saved. A hoisting device 10 according to the present invention has a hoist 30 and a control unit 32. The hoist 30 rotates a drum 12 having a wire 14 wound thereon by an oil pressure motor 42 rotatable in normal and reverse directions. To the oil pressure motor 42, operating oil is supplied from an oil pressure pump 44. The oil pressure pump 44 is a two-way discharge fixed capacity type, and rotated by a servomotor 46. An acceleration/displacement transducer 34 in the control unit 32 finds a moving direction and a moving speed of a wire hanging point in the vertical direction from an output signal of an acceleration sensor 24.

Abstract: In an electric conductivity measurement circuit according to the invention, there are provided first and second cores for forming a closed flux loop in a liquid whose electric conductivity is to be measured, a first coil is wound on the first core, and a second coil is wound on the second core in a direction opposite to the direction of the winding of the first coil, a closed circuit includes the first and second coils, a reference resistor Rr and switch means, and the switch means is periodically turned on and off to periodically incorporate the reference resistor Rr in the closed circuit, thereby calculating the electric conductivity of the liquid by comparing a voltage induced at the second coil where the reference resistor Rr is incorporated in the closed circuit, with a voltage induced at the second coil where the reference resistor Rr is not incorporated in the closed circuit.

Abstract: An apparatus and method for measuring the properties of underground water are disclosed. The device comprises a measuring apparatus with a measuring sensor for measuring the properties of the underground water, a pair of expandable and contractible packers arranged above and below the measuring apparatus, a transmitting means for sending measurement signals from the measuring apparatus, and a receiving means located at the ground surface for receiving the measurement signals from the transmitting apparatus. The method of the present invention comprises the steps of placing a measurement apparatus with a measuring sensor in a bored hole at a desired depth, arranging a pair of packers so that the measuring sensor is interposed therebetween, pumping water to the ground surface from the space between the two packers, and comparing the properties of the water pumped to the surface with the properties of the water measured with the above-mentioned measuring sensor.

Abstract: A data recorder comprises a DC motor for driving a magnetic tape, a buffer register for temporarily storing input data, a counter adapted to be counted up by a value corresponding to an amount of data stored in the buffer register, a D-A converter connected to the counter and adapted to generate an output signal in accordance with the counted value and control the rotation of the motor, and a decoder for generating an output in accordance with the rotation speed of the motor. The data is read out from the buffer register in response to the output of the decoder and recorded onto the magnetic tape while at the same time the counter is counted down.