US 12,312,222 B2Granted

Lifting mechanism

AssigneesDanfoss Power Solutions (Jiangsu) Co., Ltd, Danfoss Power Solutions Inc.

InventorsZhekang Du, Xiaozhong Chen

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Abstract

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.

Claims23

Dependent claims

A lifting mechanism, comprising:

a battery, an electric machine, a hydraulic pump, an oil tank, a hydraulic cylinder and a work platform, wherein the lifting mechanism comprises a lifting mode, a hold mode and a lowering mode, and the lowering mode comprises an energy-regeneration mode in which hydraulic fluid drives the hydraulic pump to operate as a hydraulic motor, and thus in turn hydraulic fluid drives the electric machine to operate as a generator and charge the battery,
wherein a proportional valve or switch valve is provided on a hydraulic line between the hydraulic pump and the hydraulic cylinder;
the proportional valve or switch valve comprises a bidirectional communication position and a unidirectional communication position in which the hydraulic fluid is permitted to flow from the hydraulic pump to the hydraulic cylinder in a unidirectional way;
in the lifting mode or the hold mode, the proportional valve or switch valve is in the unidirectional communication position, and in the lowering mode, the proportional valve or switch valve is in the bidirectional communication position;
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 the unidirectional communication position to the bidirectional communication position,
wherein the lowering mode further comprises a non-energy-regeneration mode, and the lifting mechanism further comprises a flow limiting valve, provided between the hydraulic cylinder and the proportional valve or switch valve, for limiting a maximum of a descending speed of the work platform, and
wherein the flow limiting valve has a throttling resistance in a second position larger than that in a first position, and when a pressure difference across the flow limiting valve is larger than a predetermined pressure difference, the flow limiting valve switches from the first position to the second position.

4 more elements

A lifting mechanism comprising:

a battery, an electric machine, a hydraulic pump, an oil tank, a hydraulic cylinder and a work platform, the lifting mechanism comprises a lifting mode, a hold mode and a lowering mode, and the lowering mode comprises an energy-regeneration mode in which hydraulic fluid drives the hydraulic pump to operate as a hydraulic motor, and thus in turn hydraulic fluid drives the electric machine to operate as a generator and charge the battery;
wherein a proportional valve or switch valve is provided on a hydraulic line between the hydraulic pump and the hydraulic cylinder;
the proportional valve or switch valve comprises a bidirectional communication position and a unidirectional communication position in which the hydraulic fluid is permitted to flow from the hydraulic pump to the hydraulic cylinder in a unidirectional way;
in the lifting mode or the hold mode, the proportional valve or switch valve is in the unidirectional communication position, and in the lowering mode, the proportional valve or switch valve is in the bidirectional communication position;
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 the unidirectional communication position to the bidirectional communication position;
wherein the lowering mode further comprises a non-energy-regeneration mode, and the lifting mechanism further comprises a flow limiting valve, provided between the hydraulic cylinder and the proportional valve or switch valve, for limiting a maximum of a descending speed of the work platform;
and
wherein the flow limiting valve comprises a first orifice and a selection valve connected with each other, the selection valve has a communicating position and a throttling position in which a second orifice takes effect, when the selection valve is in the communicating position, the flow limiting valve is in a first position, and when the selection valve is in the throttling position, the flow limiting valve is in a second position.

5 more elements

A lifting mechanism comprises:

a battery, an electric machine, a hydraulic pump, an oil tank, a hydraulic cylinder and a work platform, the lifting mechanism comprises a lifting mode, a hold mode and a lowering mode, and the lowering mode comprises an energy-regeneration mode in which hydraulic fluid drives the hydraulic pump to operate as a hydraulic motor, and thus in turn hydraulic fluid drives the electric machine to operate as a generator and charge the battery;
wherein a proportional valve or switch valve is provided on a hydraulic line between the hydraulic pump and the hydraulic cylinder;
the proportional valve or switch valve comprises a bidirectional communication position and a unidirectional communication position in which the hydraulic fluid is permitted to flow from the hydraulic pump to the hydraulic cylinder in a unidirectional way;
in the lifting mode or the hold mode, the proportional valve or switch valve is in the unidirectional communication position, and in the lowering mode, the proportional valve or switch valve is in the bidirectional communication position;
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 the unidirectional communication position to the bidirectional communication position;
wherein the lowering mode further comprises a non-energy-regeneration mode, and the lifting mechanism further comprises a flow limiting valve, provided between the hydraulic cylinder and the proportional valve or switch valve, for limiting a maximum of a descending speed of the work platform;
wherein the flow limiting valve comprises a proportional valve for continuously adjusting a flow resistance;
and
wherein the proportional valve has a maximum permissible opening degree which is set according to pre-calibrated data and in terms of a real-time pressure of the hydraulic cylinder correspondingly, or is directly set according to a maximum pressure of the hydraulic cylinder permitted by the work platform.

6 more elements

A lifting mechanism comprises:

a battery, an electric machine, a hydraulic pump, an oil tank, a hydraulic cylinder and a work platform, the lifting mechanism comprises a lifting mode, a hold mode and a lowering mode, and the lowering mode comprises an energy-regeneration mode in which hydraulic fluid drives the hydraulic pump to operate as a hydraulic motor, and thus in turn hydraulic fluid drives the electric machine to operate as a generator and charge the battery;
wherein a proportional valve or switch valve is provided on a hydraulic line between the hydraulic pump and the hydraulic cylinder;
the proportional valve or switch valve comprises a bidirectional communication position and a unidirectional communication position in which the hydraulic fluid is permitted to flow from the hydraulic pump to the hydraulic cylinder in a unidirectional way;
in the lifting mode or the hold mode, the proportional valve or switch valve is in the unidirectional communication position, and in the lowering mode, the proportional valve or switch valve is in the bidirectional communication position;
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 the unidirectional communication position to the bidirectional communication position;
wherein the lowering mode further comprises a non-energy-regeneration mode, and the lifting mechanism further comprises a flow limiting valve, provided between the hydraulic cylinder and the proportional valve or switch valve, for limiting a maximum of a descending speed of the work platform;
and
wherein the descending lowering mode comprises the non-energy-regeneration mode, the lifting mechanism further comprises a throttle valve;
in the energy-regeneration mode, a descending speed of the work platform is controlled by the electric machine;
in the non-energy-regeneration mode, the descending speed of the work platform is set by a size of an orifice of the throttle valve;
in an abnormal descending of the work platform, the maximum of the descending speed of the work platform is set by the flow limiting valve.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/887,736Filed 15 Aug 2022
Priority: CN 202111482079.26 Dec 2021
Published: US 2023/0174353 A18 Jun 2023
Granted: 27 May 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification30 codes

B66F 3/32
Constructional features: with means for avoiding excessive shocks on completion of movements
B66F 9/22
Means for actuating or controlling masts, platforms, or forks: hydraulic devices or systems
B66F 11/042
For movable platforms or cabins, e.g. on vehicles, permitting workmen to place themselves in any desired position for carrying out required…
F15B 11/04
Systems essentially incorporating special features for controlling the speed or the actuating force of an output member: for controlling the speed