Electro-hydraulic device for moving a jib
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.
1. An electro-hydraulic device for moving a jib of a luffing jib tower crane, comprising a three-phase asynchronous motor and operating elements for changing the vertical position of the jib, a lifting gear, or a slewing gear, wherein the motor is configured to switch off if the position of the jib is not changed for a predefined time period, and wherein the motor is configured to switch on again if an operating element is actuated.
2. The electro-hydraulic device of claim 1 , wherein the motor is configured to switch on again if an operating element for changing the vertical position of the jib, a lifting gear, or a slewing gear is actuated.
3. The electro-hydraulic device of claim 1 , wherein the motor is operably connected to an electronic soft starting unit.
4. A luffing jib tower crane, comprising the electro-hydraulic device of claim 1 .
5. The method of claim 2 , wherein the motor is switched on when an operating element for changing the vertical position of the jib is actuated.
6. The method of claim 2 , wherein the motor is switched on when an operating element for a lifting gear or a slewing gear is actuated.
7. A method for reducing energy consumption in a three-phase asynchronous motor of an electro-hydraulic device for moving a jib of a luffing jib tower crane, comprising
switching off the three-phase asynchronous motor when the position of the jib is not changed for a predefined time period, and
switching on again the motor when an operating element for changing the vertical position of the jib, a lifting gear, or a slewing gear is actuated.
8. The method of claim 7 , wherein the switching on step is carried out by an electronic soft starting unit operably connected to the motor.