Hitachi Construction Machinery Co., Ltd.

Hitachi, Ltd.

Takashi Yagyuu

Toshikazu Minoshima

Tomohiko Yasuda

Masami Ochiai

Tsutomu Udagawa

Kazuhiro Imaie

Takanobu Ikari

Michio Fushiki

Takao Kurosawa

Shinji Akino

Kazuo Takiguchi

Mitsuo Aihara

Yukihiko Sugiyama

Hajimu Kozawa

A loading platform is capable of tilting on a vehicle body. In accordance with a position of an operating lever for operating a hoist cylinder for tilting the loading platform and ON/OFF of a limit change switch operated by an operator, a running speed of the vehicle body is limited. If the loading platform is not seated and the limit change switch is OFF, the running speed is limited to a first speed limit or less which is low speed running. If the loading platform is not seated and the limit change switch is ON, when the operating lever is at a lowering position or a floating position, change of the speed limit to a second speed limit faster than the first speed limit is allowed. When the operating lever is at a raising or holding position, the change of the speed limit from the first speed limit is prohibited.

Conveyance vehicle

A load measuring device for a construction machine includes a processing unit for acquiring signals indicative of cylinder pressure of front and rear suspension cylinders via pressure sensors and computing a weight value of a load put on a dump body of the construction machine. When the construction machine is traveling on a curvilinear route, the construction machine makes the output of the weight value ineffective. In particular, when the differential speed value between the rear wheels, received from a speed difference detector, is below a preset value, the arithmetic unit outputs a loading weight W computed by the processing unit, as final loading weight, and so that when the differential speed exceeds the preset value, the arithmetic unit makes ineffective the computed loading weight W as the final loading weight output.

Apparatus for measuring load of construction machine

An electrically-driven dump truckuses resistors to convert electric power generated during retarder braking operation into heat energy. A body framehas front and rear wheels, a support baseA, a cabmounted on an upper left surface of the support base, and a control cabinetmounted on an upper surface of the support base. A plurality of resistor boxesare mounted on an upper base plateB and are arranged in a stacked manner such that the plurality of resistor boxesare located to the right of the control cabinetin order to secure right side visibility from the cab. Each resistor box has a casing with plural resistors connected in parallel, an inlet port and an outlet port. A fan for cooling the resistors is housed in the casing.

Electrically-driven dump truck

A hydraulic drive system comprises directional flow control valves (-) for selectively supplying a hydraulic fluid from a first hydraulic pump (), inflow control valves (-) disposed respectively in branch lines (A-C) branched from a supply line () for supplying a hydraulic fluid delivered from a second hydraulic pump () to rod pushing-side chambers (A,A,A,A) of hydraulic cylinders, a bypass flow control valve () disposed in a line () connecting the supply line () and a reservoir (), and a controller () for computing control variables corresponding to operation command signals from control levers () and controlling the inflow control valves (-) and the bypass flow control valve () in accordance with the computed control variables. Thus, the number of flow control valves and the length of piping required for their connection can be reduced, and a total pressure loss can be further reduced.

Hydraulic driving system of construction machinery

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Ushiku, Japan

Takashi Yagyuu