Valve unit for a quick-changer and quick-change system

1. A valve unit for the exclusive hydraulic actuation of the locking means of a mechanical quick-changer for attachments of a construction machine, wherein

the valve unit comprises a feed pressure connector, a first valve unit outlet for connecting an unlocking pressure line, a second valve unit outlet for connecting a locking pressure line, at least one discharge to the tank, and at least two switchable directional valves, with the feed pressure connector being connected or connectable to the first valve unit outlet via a serial connection of the at least two switchable directional valves, and

the valve unit comprises an integrated pressure store and/or a separate store connector for an external pressure store, with the internal pressure store and/or the external pressure store connector being connected or connectable to the second valve unit outlet.

2. A valve unit in accordance with claim 1 , wherein the second valve unit outlet can only be connected to the feed pressure connector via a directional valve.

3. A valve unit in accordance with claim 1 , wherein a pressure-reducing valve is provided at the feed pressure connector.

4. A valve unit in accordance with claim 1 , wherein the at least two directional valves are electrically actuable.

5. A valve unit in accordance with claim 4 , wherein the at least two directional valves are controllable via two separate control channels.

6. A valve unit in accordance with claim 1 , wherein the at least two directional valves are different valve types.

7. A valve unit in accordance with claim 6 , wherein the at least two directional valves include a poppet valve and a gate valve.

8. A valve unit in accordance with claim 1 , wherein both directional valves are switched in the currentless state such that a connection of the feed pressure connector to the second valve unit outlet is present, both directional valves are in particular preloaded and switch into the second switching position in the currentless state.

9. A valve unit in accordance with claim 1 , wherein the valve unit comprises one or more pressure sensors or connectors for external pressure sensors, with pressure sensors or connector points being provided for detecting the system pressure and/or the pressure at the first and/or second valve unit outlets.

10. A quick-change system having at least one quick-change adapter for installing an attachment and having at least one valve unit in accordance with claim 1 .

11. A quick-change system in accordance with claim 10 , wherein the quick-change adapter comprises a locking means and connectors for a locking pressure line and an unlocking pressure line, with the locking pressure connector being connected to the locking means via at least one check valve.

12. A quick-change system in accordance with claim 11 , wherein the locking means include at least one hydraulic cylinder and the check valve is controllable for the release as required of a volume pressure backflow from the locking means.

13. A quick-change system in accordance with claim 12 , wherein the check valve is hydraulically controlled with a hydraulic control line connected to the unlocking pressure line.

14. A construction machine having at least one valve unit in accordance with claim 1 , wherein the valve unit is integrated in a superstructure of the construction machine.

15. The construction machine in accordance with claim 14 , which is a hydraulic excavator.

16. A valve unit for the exclusive hydraulic actuation of the locking means of a mechanical quick-changer for attachments of a construction machine, wherein

the valve unit comprises a feed pressure connector, a first valve unit outlet for connecting an unlocking pressure line, a second valve unit outlet for connecting a locking pressure line, at least one discharge to the tank, and at least two switchable directional valves, with the feed pressure connector being connected or connectable to the first valve unit outlet via a serial connection of the at least two switchable directional valves, and

a first directional valve comprises two switching states, with the first switching state connecting the feed pressure connector of the valve unit to the second directional valve and the second switching state connecting the feed pressure connector to the second valve unit outlet.

17. A valve unit in accordance with claim 16 , wherein the second directional valve comprises two switching states to release the connection of the first directional valve to the first valve unit outlet in a first switching state or to block it in a second switching state, ideally to block it in the direction of flow of the first valve unit outlet, such that a backflow from the first valve unit outlet via the second directional valve, and optionally the first directional valve, into the tank is possible, with the second directional valve preferably being connected to the tank via the first directional valve in the second switching state.

18. A valve unit for the exclusive hydraulic actuation of the locking means of a mechanical quick-changer for attachments of a construction machine, wherein

the valve unit comprises a feed pressure connector, a first valve unit outlet for connecting an unlocking pressure line, a second valve unit outlet for connecting a locking pressure line, at least one discharge to the tank, and at least two switchable directional valves, with the feed pressure connector being connected or connectable to the first valve unit outlet via a serial connection of the at least two switchable directional valves, and

a pressure shut-off valve is connected between the first directional valve and the second valve unit outlet and blocks the flow from the first directional valve to the second valve unit outlet when the pressure level at the second valve unit outlet exceeds a limit pressure, with the limit pressure preferably being able to be defined by the pressure at the second valve unit outlet and/or an adjustable pressure portion.

19. A valve unit for the exclusive hydraulic actuation of the locking means of a mechanical quick-changer for attachments of a construction machine, wherein

the valve unit comprises a feed pressure connector, a first valve unit outlet for connecting an unlocking pressure line, a second valve unit outlet for connecting a locking pressure line, at least one discharge to the tank, and at least two switchable directional valves, with the feed pressure connector being connected or connectable to the first valve unit outlet via a serial connection of the at least two switchable directional valves, and

the pressure shut-off valve opens the flow from the first directional valve to the second valve unit outlet when the pressure level at the first valve unit outlet exceeds a limit pressure, with the limit pressure preferably being able to be defined by the pressure at the first valve unit outlet and/or an adjustable pressure portion.