A hydraulic control device includes: a recovery oil passage; a regenerative motor that rotates an output shaft of an engine in response to a supply of the hydraulic fluid and is driven to rotate by rotation of the output shaft of the engine; a regenerative oil passage for guiding return oil from a boom cylinder to the regenerative motor without passing the return oil through the recovery oil passage; a coupling oil passage that couples the recovery oil passage and the regenerative oil passage to each other; and a regeneration-side check valve that is provided on the coupling oil passage, and allows the hydraulic fluid to flow from the recovery oil passage toward the regenerative motor, and moreover restricts the hydraulic fluid from flowing from the regenerative motor toward the recovery oil passage.

The lifting mechanism includes a battery, an electric machine, a hydraulic pump, an oil tank, a hydraulic cylinder, a work platform and a proportional valve or switch valve. In the energy-regeneration mode, the hydraulic fluid drives the hydraulic pump to operate as a hydraulic motor, thus in turn driving the electric machine to operate as a generator and charge the battery. In the present application, the hydraulic pump operates to increase a pressure in a hydraulic line between the hydraulic pump and the proportional valve or switch valve before the proportional valve or switch valve is switched from a unidirectional communication position to a bidirectional communication position. When the proportional valve or switch valve is switched from the unidirectional communication position to the bidirectional communication position, by increasing the pressure in the hydraulic line, it could be avoided that the volume of hydraulic fluid has low pressure is compressed because the hydraulic fluid has low pressure is communicated with hydraulic fluid has high pressure; therefore a state of sudden drop of the work platform is avoided, and safety performance and operating experience of the lifting mechanism is improved.

The lifting mechanism includes a battery, an electric machine, a hydraulic pump, an oil tank, a hydraulic cylinder, a work platform and a proportional valve or switch valve. In the energy-regeneration mode, the hydraulic fluid drives the hydraulic pump to operate as a hydraulic motor, thus in turn driving the electric machine to operate as a generator and charge the battery. In the present application, the hydraulic pump operates to increase a pressure in a hydraulic line between the hydraulic pump and the proportional valve or switch valve before the proportional valve or switch valve is switched from a unidirectional communication position to a bidirectional communication position. When the proportional valve or switch valve is switched from the unidirectional communication position to the bidirectional communication position, by increasing the pressure in the hydraulic line, it could be avoided that the volume of hydraulic fluid has low pressure is compressed because the hydraulic fluid has low pressure is communicated with hydraulic fluid has high pressure; therefore a state of sudden drop of the work platform is avoided, and safety performance and operating experience of the lifting mechanism is improved.

Provided is a hydraulic shovel capable of moving a boom, an arm, and a bucket at respective adequate speeds even during complex operations thereof, without a significant pressure loss. This hydraulic shovel includes: a first pump (31) connected to a boom actuator (24) and a bucket actuator (28); a second pump (32) connected to an arm actuator (26) and the boom actuator (24); a third pump (33) connect to the arm actuator (26); a boom control valve (54) interposed between the first pump (31) and the boom actuator (24); an arm control valve (56) interposed between the second pump (32) and the arm actuator (26); a bucket control valve (58) interposed between the first pump (31) and the bucket actuator (28); a boom merging valve (55) for speed increase interposed between the second pump (32) and the boom actuator (24); and an arm merging valve (57) for speed increase interposed between the third pump (33) and the arm actuator (26).

Provided is a hydraulic shovel capable of moving a boom, an arm, and a bucket at respective adequate speeds even during complex operations thereof, without a significant pressure loss. This hydraulic shovel includes: a first pump (31) connected to a boom actuator (24) and a bucket actuator (28); a second pump (32) connected to an arm actuator (26) and the boom actuator (24); a third pump (33) connect to the arm actuator (26); a boom control valve (54) interposed between the first pump (31) and the boom actuator (24); an arm control valve (56) interposed between the second pump (32) and the arm actuator (26); a bucket control valve (58) interposed between the first pump (31) and the bucket actuator (28); a boom merging valve (55) for speed increase interposed between the second pump (32) and the boom actuator (24); and an arm merging valve (57) for speed increase interposed between the third pump (33) and the arm actuator (26).

A switching unit may be provided for connecting a first pneumatic unit and a second pneumatic unit of a pneumatic system together. The switching unit comprises a main body having: a channel structure which extends through the main body; a first and a second inlet for introducing a pressure into the channel structure; a first and a second outlet for discharging at least some of the pressure from the channel structure; and a first and a second valve; wherein the first inlet can be brought into a pressure-exchange connection to the first outlet via a first channel by setting a first switch position of the first valve or to the second outlet via a second channel by setting a second switch position of the first valve, and wherein the second inlet can be brought into a pressure-exchange connection to the first outlet via a third channel by setting a first switch position of the second valve or to the second outlet via a fourth channel by setting a second switch position of the second valve.

A switching unit may be provided for connecting a first pneumatic unit and a second pneumatic unit of a pneumatic system together. The switching unit comprises a main body having: a channel structure which extends through the main body; a first and a second inlet for introducing a pressure into the channel structure; a first and a second outlet for discharging at least some of the pressure from the channel structure; and a first and a second valve; wherein the first inlet can be brought into a pressure-exchange connection to the first outlet via a first channel by setting a first switch position of the first valve or to the second outlet via a second channel by setting a second switch position of the first valve, and wherein the second inlet can be brought into a pressure-exchange connection to the first outlet via a third channel by setting a first switch position of the second valve or to the second outlet via a fourth channel by setting a second switch position of the second valve.

A hydraulic system including a first cylinder conduit configured to couple to a cylinder, a second cylinder conduit configured to fluidly coupled to the cylinder, and a bypass conduit fluidly coupled both to the first cylinder conduit upstream of the cylinder and to the second cylinder conduit downstream of the cylinder. The bypass conduit is configured to enable intermittent fluid flow of a hydraulic fluid from the first cylinder conduit to the second cylinder conduit while bypassing at least a portion of the cylinder.

A hydraulic system including a first cylinder conduit configured to couple to a cylinder, a second cylinder conduit configured to fluidly coupled to the cylinder, and a bypass conduit fluidly coupled both to the first cylinder conduit upstream of the cylinder and to the second cylinder conduit downstream of the cylinder. The bypass conduit is configured to enable intermittent fluid flow of a hydraulic fluid from the first cylinder conduit to the second cylinder conduit while bypassing at least a portion of the cylinder.

A hydraulic control assembly for a plurality of consumers includes, for each consumer, a supply metering orifice configured to control fluid flow. A flow-sensing fluid-flow-path extends over detection orifices positioned hydraulically in series, whereby a detection orifice is assigned to each supply metering orifice. The fluid-flow-path is connected to a hydraulic pump upstream of the detection orifices, and a control device of the hydraulic pump downstream of the detection orifices. Each detection orifice is configured to close the fluid-flow-path upon detecting a fluid supply deficiency for a corresponding consumer, whereby the control device is configured to interact with the fluid-flow-path such that fluid flow from the hydraulic pump is increased. When no customers have a supply deficiency, the fluid-flow-path over the detection orifices is fully opened, and the control device is configured to reduce fluid flow from the hydraulic pump.