HK1204599B - Electrohydraulic device for crane boom operation - Google Patents
Electrohydraulic device for crane boom operation Download PDFInfo
- Publication number
- HK1204599B HK1204599B HK15105259.8A HK15105259A HK1204599B HK 1204599 B HK1204599 B HK 1204599B HK 15105259 A HK15105259 A HK 15105259A HK 1204599 B HK1204599 B HK 1204599B
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- HK
- Hong Kong
- Prior art keywords
- electro
- jib
- motor
- hydraulic
- hydraulic device
- Prior art date
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Abstract
The invention relates to an electro-hydraulic device for moving a jib for a tower crane, in which device the motor of the hydraulic unit is switched off when the position of the jib is not altered for a predetermined time period.
Description
The invention relates to an electro-hydraulic device for adjusting a projector and a tower crane with a swivel bearing with such a device.
The vertical positioning of the projector can be achieved by means of a hydraulic cylinder, which is driven in and out of the crankshaft/rope axis to achieve the desired distance, in the case of tower cranes with a swivel bearing, whereby a hydraulic unit comprising an oil pump provides the required amount of oil for the transmission of the force at the required pressure.
When the outlet has reached the desired angle, i.e. no further in- or out-flow is required, a change in oil quantity or oil pressure at the hydraulic cylinder is no longer required.
In the case of a hydraulically adjustable swivel crane, the motor driving the hydraulic unit is usually a DC motor.
A DC motor running at idle has a very poor power factor and efficiency, however. During the idle phase, the DC motor continues to consume energy. A large part of this energy consumption, estimated to be about 60%, is unnecessary; the energy is only used to transport the oil empty in the circuit, but not for the work of the hydraulic cylinder.
In addition, the noise produced by the hydraulic unit is only negligibly less pronounced in idle mode than in normal operation.
The task was therefore to provide an electro-hydraulic device for adjusting a beam for a tower crane, which reduces the energy consumption for adjusting the beam and noise generation.
This task is solved by an electro-hydraulic device to adjust a projector as described in claim 1.
The test shall be carried out with a lifting tower crane as described in claim 4.
Other embodiments are covered by the subclaims or described below.
The electro-hydraulic device according to the invention for adjusting a projector causes a time delayed shutdown of the engine if no changing oil pressure on the hydraulic cylinder is required for a predetermined period (= delay time).
The engine must be restarted and the engine must be running at a certain speed, so that it is always necessary to consider whether the interruption is long enough to save energy over the delay in movement which is disruptive to the crane driver.
The time taken for the engine to start up and start up is particularly advantageous if it is kept low by an optimized electrical or electronic start-up. The delay time can then be chosen to be even less; and thus the energy saving is improved.
Preferably, the delay time can be adjusted as desired in the electro-hydraulic bearing arrangement of the invention.
If the position of the outlet is changed again, the engine shall be restarted when the controls for the outlet are actuated.
The working time of a crane per year can be estimated at 260 days times 10 hours, which equals 2600 hours. The average downtime of a crane is about 60%, i.e. 1560 hours. For example, if we assume that the idle power losses are 1.1 kW at a rated power of 22 kW, the energy savings in this example are 1,700 kWh per year.
The system may be so designed that a restart of the engine is effected not only by an initiated change in the bearing angle but also by any other movement of the crane, such as that of the crankshaft or of the crankshaft.
Claims (4)
- An electro-hydraulic device for moving a jib for a tower crane, wherein the electro-hydraulic device comprises a hydraulic assembly with a motor, characterized in that a switching off of the motor of the hydraulic assembly is carried out if the position of the jib is unchanged for a predetermined period of time.
- The electro-hydraulic device for moving a jib according to Claim 1, characterized in that a renewed switching on of the motor is carried out if the operating element(s) for changing the vertical position of the boom, the lifting gear, or the slewing gear is/are actuated.
- The electro-hydraulic device for moving a jib according to Claim 1 or 2, characterized in that the motor is a three-phase asynchronous motor.
- A derricking-jib tower crane comprising an electro-hydraulic device for moving a jib according to one of the preceding claims.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102012010759.5 | 2012-05-31 | ||
| DE102012010759A DE102012010759A1 (en) | 2012-05-31 | 2012-05-31 | Electrohydraulic device for adjusting a boom |
| PCT/EP2013/060181 WO2013178480A1 (en) | 2012-05-31 | 2013-05-16 | Electro-hydraulic device for moving a jib |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| HK1204599A1 HK1204599A1 (en) | 2015-11-27 |
| HK1204599B true HK1204599B (en) | 2017-09-01 |
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