Abstract: A concrete agitating drum (1) is driven by a hydraulic motor (81). A connection switch-over valve (20) is arranged to have a function to regulate a flow cross-sectional area of pressurized working oil supplied to the hydraulic motor (81) from a variable capacity hydraulic pump (10). The variable capacity hydraulic pump (10) is driven by a combustion engine (60) together with a charge pump (11). When a discharge pressure of the charge pump (11) is low, the connection switch-over valve (20) maintains a small flow cross-sectional area to rotate the agitating drum (1) at a low rotation speed so that fuel consumption of the combustion engine (60) is suppressed to be small. When the discharge pressure of the charge pump (11) becomes high, the connection switch-over valve (20) enlarges the flow cross-sectional area, thereby realizing a rated rotation speed of the agitating drum (1).

Abstract: A variable capacity hydraulic pump (10) drives a concrete agitating drum (1) via a hydraulic motor (81). A hydraulic actuator (14) regulates a discharge flow rate of the hydraulic pump (10) depending on an actuator driving pressure. A load sensing valve (40) generates the actuator driving pressure by reducing a discharge pressure of the hydraulic pump (10) according to a differential pressure between the discharge pressure and a load pressure acting on the hydraulic motor (81). A shut-off valve (20) shuts off supply of the pressurized oil discharged from the hydraulic pump (10) to the hydraulic motor (81). Due to this action, when the differential pressure increases beyond a predetermined differential pressure, an unload valve (30) drains the discharged oil, thereby preventing the hydraulic pump (10) from generating noise due to an excessive increase in the discharge pressure.

Abstract: A concrete agitating drum (1) is driven by a hydraulic motor (81). A connection switch-over valve (20) is arranged to have a function to regulate a flow cross-sectional area of pressurized working oil supplied to the hydraulic motor (81) from a variable capacity hydraulic pump (10). The variable capacity hydraulic pump (10) is driven by a combustion engine (60) together with a charge pump (11). When a discharge pressure of the charge pump (11) is low, the connection switch-over valve (20) maintains a small flow cross-sectional area to rotate the agitating drum (1) at a low rotation speed so that fuel consumption of the combustion engine (60) is suppressed to be small. When the discharge pressure of the charge pump (11) becomes high, the connection switch-over valve (20) enlarges the flow cross-sectional area, thereby realizing a rated rotation speed of the agitating drum (1).

Abstract: An agitating drum driving device comprises a hydraulic motor (81) for rotating an agitating drum (1), and a swash-plate type hydraulic pump (10) connected to a combustion engine (60) to supply pressurized oil to drive the hydraulic motor (81). When the engine rotation speed is not higher than a predetermined speed, the swash-plate angle of a swash-plate (64) is regulated to keep a differential pressure between a pressure of the pressurized oil and a load pressure acting on the hydraulic motor (81) constant. When the engine rotation speed rises above the predetermined speed, the flow rate of the pressurized oil is increased as the engine rotation speed increases while relatively decreasing an increasing rate of the flow rate of the pressurized oil with respect to an increase rate of the engine rotation speed as the engine rotation speed increases.

Abstract: An agitating drum driving device comprises a hydraulic motor (81) for rotating an agitating drum (1), and a swash-plate type hydraulic pump (10) connected to a combustion engine (60) to supply pressurized oil to drive the hydraulic motor (81). When the engine rotation speed is not higher than a predetermined speed, the swash-plate angle of a swash-plate (64) is regulated to keep a differential pressure between a pressure of the pressurized oil and a load pressure acting on the hydraulic motor (81) constant. When the engine rotation speed rises above the predetermined speed, the flow rate of the pressurized oil is increased as the engine rotation speed increases while relatively decreasing an increasing rate of the flow rate of the pressurized oil with respect to an increase rate of the engine rotation speed as the engine rotation speed increases.

Abstract: A variable capacity hydraulic pump (10) drives a concrete agitating drum (1) via a hydraulic motor (81). A hydraulic actuator (14) regulates a discharge flow rate of the hydraulic pump (10) depending on an actuator driving pressure. A load sensing valve (40) generates the actuator driving pressure by reducing a discharge pressure of the hydraulic pump (10) according to a differential pressure between the discharge pressure and a load pressure acting on the hydraulic motor (81). A shut-off valve (20) shuts off supply of the pressurized oil discharged from the hydraulic pump (10) to the hydraulic motor (81). Due to this action, when the differential pressure increases beyond a predetermined differential pressure, an unload valve (30) drains the discharged oil, thereby preventing the hydraulic pump (10) from generating noise due to an excessive increase in the discharge pressure.

Abstract: An arrangement of memory-card accommodating portions in a recording and reproducing apparatus includes a plurality of card slots for respectively accommodating memory cards capable of recording and reproducing an audio or image signal disposed adjacent to each other in a mutually overlapping relation, and eject buttons for ejecting the memory cards disposed in individual correspondence with the card slots. A set of at least two of the card slots are arranged so that the memory cards are disposed in parallel with each other.

Abstract: In memory-card accommodating portions in a recording and reproducing apparatus in which a plurality of card slots 16 for respectively accommodating memory cards MC are disposed adjacent to each other in a mutually overlapping relation, and eject buttons 15 for ejecting the memory cards are disposed in individual correspondence with the card slots 16, a set of at least two of the card slots 16 are arranged such that the memory cards MC are disposed in parallel with each other and are accommodated in a state in which at least partial areas of surfaces of the memory cards MC oppose each other, and the eject buttons 15 are arranged at positions which are respectively adjacent to the plurality of card slots 16 in a unique manner and which do not overlap in a direction parallel to the surface of the inserted memory card MC, in order to prevent the eject buttons 15 from being disposed close to each other.

Abstract: A liquid crystal display control device uses first and second common signals supplied to two segments forming a pair in a liquid crystal display element to always generate four kinds of segment signals synchronizing with these two common signals and selectively supply one segment signal among them to the two segments to control their display operations.