EP3789612B1 - Portable, battery-powered hydraulic unit for hydraulic rescue equipment - Google Patents

Description

The invention relates to a portable, battery-powered hydraulic unit for hydraulic rescue tools, in particular for spreading and/or scissor tools, and a method for operating a portable, battery-powered hydraulic unit, as specified in the claims.

Hydraulic rescue tools are known in particular as spreader and/or scissor tools and are typically used by rescue organizations, such as the fire brigade or the technical assistance service, but also by special forces. In order to ensure that such rescue or operational tools are ready for use quickly, efforts are being made to make these technical aids portable or wearable and thus to implement them as light-weight as possible. In order to enable operation that is independent of power generators or power supply networks, the hydraulic units for activating the hydraulic rescue tools can increasingly be operated by electrochemical energy stores, in particular by accumulators. Generic battery-powered hydraulic units for hydraulic rescue tools, which hydraulic units should be portable and operable by just one person, are available from the applicant in a number of designs. The respective hydraulically actuated rescue tools are permanently or interchangeably fastened or mounted on the portable, battery-operated hydraulic unit and thus form a one-piece unit or the portable, battery-operated hydraulic units are designed as separate devices and can be connected to the respective rescue tool via hydraulic hose connections. When the hydraulic rescue equipment reaches an end position or when it is blocked due to the operating conditions, or when the available power is no longer sufficient for a work movement, the excess pressure generated by the hydraulic pump is reduced by the activation of a pressure relief valve. In addition to undesirable hydraulic power loss, this usually results in high noise and heat emissions. However, economical and efficient use of the available battery power is of great importance, especially for rescue operations, and is often decisive for the successful completion of the operation. In addition, it is desirable to reduce the stress level for to keep the emergency services as far back as possible by keeping noise and heat emissions at a low level.

The task of using the battery life economically and efficiently according to the state of the art is usually solved by structurally complex and expensive load-sensing systems. The hydraulic pump always delivers that volume flow that is currently required by the consumer. In addition to their technical complexity, these load-sensing systems also have the disadvantage of high waste heat or high energy consumption and are subject to signs of wear and an associated unsatisfactory service life. The structural complexity of these systems also entails weight disadvantages, which affect their portability.

The basic technical structure of a generic, previously known hydraulic unit is for example in EP 1 598 555 B1 disclosed. Therein, the hydraulic power, which is made available by a hydraulic pump driven by an electric motor, is limited with electronic control means. A microprocessor calculates a maximum limit current and uses it to regulate the engine speed and subsequently the hydraulic pressure generated by the hydraulic pump.

In the EP 2610528 A2 discloses that a control unit estimates a hydraulic pressure of the hydraulic fluid based on a driving current for the motor and a rotational speed of the motor, and based on this estimated hydraulic pressure value, performs a driving control for the motor.

Also the EP 0718496 A2 describes an electrohydraulic system having at least one hydraulic load that receives pressurized fluid from a pump driven by an electric motor. The flow or pressure characteristics of the fluid are determined by the motor speed, which is set by an electronic controller in response to a motor/pump parameter sensed in the controller itself. No system parameters are recorded outside of the electronic control.

The DE 102015214006 A1 discloses a method for measuring the pressure that is generated by an electric motor-driven compressor, the change in the pressure at the compressor outlet being dependent on the change in the average motor current of the electric motor driving the compressor being determined and used as a pressure-proportional variable for the Operation of the compressor is provided to a control device in the form of an input variable or is displayed. Furthermore, the pressure measurement carried out via the average motor current can also be used for maximum pressure limitation by a control unit. An additional mechanical pressure limitation is then no longer necessary.

The object of the present invention is to create a simple and improved, portable, battery-powered hydraulic unit, in particular to further optimize its running time, so that complex or long rescue operations can be carried out efficiently.

This object of the invention is achieved by a generic hydraulic unit with the characterizing features of claim 1, and by a method for operating this hydraulic unit with the characterizing features of claim 8.

• eine Steuerungsvorrichtung;
• wenigstens eine Hydraulikpumpe;
• wenigstens eine erste und eine zweite Druckleitung, welche mit einem Druckabgang der Hydraulikpumpe gekoppelt sind;
• einen Hydrauliktank für eine Hydraulikflüssigkeit;
• wenigstens einen Akkupack;
• eine elektromechanische Schnittstelle zur bedarfsweisen An- und Abkopplung von dem wenigstens einen Akkupack;
• eine mechanisch-hydraulische Schnittstelle zur Anbindung des hydraulischen Rettungswerkzeuges
• und einem Elektromotor zum Antreiben der zumindest einen Hydraulikpumpe. Des Weiteren ist ein Druckbegrenzungsventil ausgebildet, welches derart angeordnet ist, dass bei Erreichen eines Maximaldrucks in wenigstens einer der Druckleitungen die Hydraulikflüssigkeit über das Druckbegrenzungsventil und eine mit diesem gekoppelte Rückflussleitung in den Hydrauliktank rückgeführt wird, und dass eine Druckbegrenzungsventil-Zustandserfassung derart ausgebildet ist, um das Ansprechen des Druckbegrenzungsventils zu detektieren. Die Steuerungsvorrichtung ist dabei derart ausgebildet, um die Motordrehzahl des Elektromotors infolge der Detektion des Ansprechens des Druckbegrenzungsventils zu reduzieren.

The invention relates to a portable, battery-powered hydraulic unit for hydraulic rescue tools, in particular for spreading and/or scissor tools

• a controller;
• at least one hydraulic pump;
• at least a first and a second pressure line, which are coupled to a pressure outlet of the hydraulic pump;
• a hydraulic tank for a hydraulic fluid;
• at least one battery pack;
• an electromechanical interface for coupling and decoupling the at least one battery pack as required;
• a mechanical-hydraulic interface for connecting the hydraulic rescue tool
• and an electric motor for driving the at least one hydraulic pump. Furthermore, a pressure relief valve is provided, which is arranged in such a way that when a maximum pressure is reached in at least one of the pressure lines, the hydraulic fluid is returned to the hydraulic tank via the pressure relief valve and a return flow line coupled to it, and that a pressure relief valve status detector is designed to to detect the response of the pressure relief valve. The control device is designed in such a way that it reduces the engine speed of the electric motor as a result of the detection of the response of the pressure-limiting valve.

A pressure-limiting valve status detection system designed in this way can advantageously contribute to detecting the response of the pressure-limiting valve in order to counteract hydraulic power loss and noise and heat emissions. These measures improve the energy efficiency of the hydraulic unit. Rescue operations or criminal investigation operations that are usually time-critical and also stressful for operators can thus be handled as professionally as possible. Furthermore, the longevity of the hydraulic unit can be improved.

Furthermore, it can be expedient if a detection means is formed, which can detect the response of the pressure relief valve by detecting the position of a valve body. If a maximum pressure preset in the pressure-limiting valve via a compression spring is exceeded, a piston slide begins to press against the compression spring, thereby displacing the valve body. Surprisingly, by detecting the position of the valve body, the shortest possible detection time and particularly reliable status detection can be achieved.

Advantageously, the position of the valve body can be detected via an optical motion sensor or Hall sensor. Alternatively, a change in the position of the valve body can also be detected by measuring the pressure. As a result of this design, the response of the pressure-limiting valve is advantageously recognized immediately and without a time delay. Since, according to this embodiment, the detection means are arranged directly on the pressure-limiting valve, the detected measurement signals are not or only slightly influenced by interference signals.

Furthermore, it can be provided that a detection means is formed, which can detect the response of the pressure relief valve by detecting the power consumption of the electric motor. In particular, this has the advantage that no additional structural unit is required to detect the response of the pressure-limiting valve. The structural complexity and the manufacturing costs can be kept as low as possible.

In particular, it can be provided that a detection means is formed, which can detect the response of the pressure relief valve by detecting the motor current. This detection device is simple to implement structurally, with the motor current usually already being detected in existing systems. In addition, in this particular variant no additional control line between the pressure relief valve, control device and electric motor required. Overall, no further components or detection means have to be added, which means that the weight of the rescue device does not increase and its structural complexity does not increase.

Also advantageous is an embodiment according to which it can be provided that a detection means is formed, which can detect the response of the pressure relief valve by detecting the torque and the speed of the electric motor and the motor power that can be calculated therefrom. This detection device is also comparatively easy to implement, since existing detection means can also be used here and no additional control line is required between the pressure-limiting valve, control device and electric motor.

According to a further development, it is possible for a detection means to be formed which can detect the response of the pressure-limiting valve by detecting the flow in the return line downstream of the pressure-limiting valve. Flow meters are standard measuring equipment and can be easily integrated into existing systems. Since the flow can be measured directly after the pressure relief valve, the measuring signal is not or only slightly falsified by interference signals.

Furthermore, it can be expedient if a signaling means is formed which can communicate the reduction in engine speed as a result of the response of the pressure relief valve to the operator of the hydraulic rescue tool by means of a signal, preferably an acoustic, visual and/or haptic signal. This further development can contribute to reducing the stress on the operator, since it can be communicated directly to the operator that the rescue device has reached an end position, is blocked, or that the available power is no longer sufficient for a working movement. It can also be useful if the signal is repeated at periodic intervals as long as the pressure relief valve responds or the engine speed is reduced.

• eine Steuerungsvorrichtung;
• wenigstens eine Hydraulikpumpe;
• wenigstens eine erste und eine zweite Druckleitung, welche mit einem Druckabgang der Hydraulikpumpe gekoppelt sind;
• einen Hydrauliktank für eine Hydraulikflüssigkeit;
• wenigstens einen Akkupack;
• eine elektromechanische Schnittstelle zur bedarfsweisen An- und Abkopplung von dem wenigstens einen Akkupack;
• eine mechanisch-hydraulischen Schnittstelle zur Anbindung des hydraulischen Rettungswerkzeuges
• und einem Elektromotor zum Antreiben der zumindest einen Hydraulikpumpe.

The invention also relates to a method for operating a portable, battery-powered hydraulic unit for hydraulic rescue tools, in particular for spreading and/or scissor tools, the hydraulic unit comprising the following components:

• a controller;
• at least one hydraulic pump;
• at least a first and a second pressure line, which are coupled to a pressure outlet of the hydraulic pump;
• a hydraulic tank for a hydraulic fluid;
• at least one battery pack;
• an electromechanical interface for coupling and decoupling the at least one battery pack as required;
• a mechanical-hydraulic interface for connecting the hydraulic rescue tool
• and an electric motor for driving the at least one hydraulic pump.

In addition, it is provided that when a maximum pressure is reached in at least one of the pressure lines, a pressure-limiting valve responds, the hydraulic fluid being returned to the hydraulic tank via the pressure-limiting valve and a return line coupled to it. The response of the pressure-limiting valve is detected by means of a pressure-limiting valve status detection and the motor speed of the electric motor is reduced by the control line as a result of the detection of the response of the pressure-limiting valve.

This reduction in engine speed as a result of reaching a maximum pressure simultaneously reduces the hydraulic power loss as well as noise and heat emissions. This increases the achievable service life of the rescue device. Surprisingly, as an additional effect, the stress on the operator is also reduced due to the lower maximum noise level.

Furthermore, it can be provided that the response of the pressure relief valve is detected by detecting the position of a valve body. If a maximum pressure preset in the pressure-limiting valve via a compression spring is exceeded, a piston slide begins to press against the compression spring, thereby displacing the valve body.

Advantageously, the position of the valve body can be detected via an optical motion sensor or Hall sensor. Alternatively, a change in the position of the valve body can also be detected by measuring the pressure. As a result of this design, the response of the pressure-limiting valve is advantageously recognized immediately and without delay and thus enables the control device to react quickly. Since, according to this embodiment, the detection means are arranged directly on the pressure-limiting valve, the detected measurement signals are not or only slightly influenced by interference signals. According to a special embodiment, it is possible for the response of the pressure-limiting valve to be detected by detecting the power consumption of the electric motor.

According to an advantageous development, it can be provided that the response of the pressure-limiting valve is detected by detecting the motor current. This detection method is easy to implement structurally, with the motor current usually already being detected in existing systems. In addition, in this special variant, no additional control line is required between the pressure-limiting valve, the control device and the electric motor. Overall, no further components or detection means have to be added, which means that the weight of the rescue device does not increase and its structural complexity does not increase.

In particular, it can be advantageous if the response of the pressure-limiting valve is detected by detecting the torque and the speed of the electric motor and the motor power that can be calculated therefrom. This detection device is also comparatively easy to implement, since existing detection means can also be used here and no additional control line is required between the pressure-limiting valve, control device and electric motor.

Furthermore, it can be provided that the response of the pressure relief valve is detected by detecting the flow in the return line after the pressure relief valve. Flow meters are standard measuring equipment and can be easily integrated into existing systems. Since the flow can be measured directly after the pressure relief valve, the measuring signal is not or only slightly falsified by interference signals.

In addition, it can be provided that a time monitoring device in the control device detects the duration of the response of the pressure limiting valve and the engine speed is reduced via the control device as soon as a defined duration of this state is reached or exceeded. As a result, the control device only acts to regulate or control the engine speed when the rescue tool has reached an end position or is blocked or the available power is no longer sufficient for a working movement. In addition, this feature ensures that, for example, a short-term blockage of the rescue tool does not lead to an immediate reduction in the engine speed and thus the work power available for the rescue operation.

Also advantageous is an embodiment according to which it can be provided that the defined duration until the engine speed is reduced is specified in the control device and/or is or can be specified individually by a user. This measure enables increased flexibility and adaptability for the operator.

According to a further development it is possible that the defined duration is preferably between 0.5 s and 2 s. Too rapid action of the control device on the engine speed is often undesirable in order not to restrict the availability of the rescue tool in the rescue operation. Too sluggish a reaction of the control device is also undesirable in order to achieve the desired energy saving as quickly as possible.

Furthermore, it can be expedient for the control device to reduce the engine speed by at least 10%, preferably by up to 50%, of the previously applied engine speed. With the associated lower power consumption of the motor, energy savings are achieved, with the rescue device still being available with sufficient power for further work movements or being able to reach its maximum work output again as quickly as possible.

In addition, it can be provided that the control device cancels the reduction in engine speed as soon as the pressure-limiting valve no longer responds. This has the advantage that the rescue tool is continuously and unrestrictedly available at full power for the rescue operation.

In a preferred embodiment variant, it is advantageous that the control device never reduces the engine speed below a defined lower limit value, in particular never lets it fall below 20% of the operating or load speed. This measure is of safety-relevant importance for the operator, since the engine or hydraulic noise always informs him that the hydraulic unit is running and ready for use. In this way, errors by the operator or even injuries to the same are avoided. As an additional positive effect, this measure improves the response behavior of the hydraulic rescue device.

Furthermore, it can be provided that the control device cancels the reduction in engine speed after a defined period of time, in which defined period of time the pressure-limiting valve no longer responds. This is beneficial in that the rescue tool is constantly available at full power for the rescue operation and at the same time it is avoided that short-term states in which the pressure relief valve does not respond are not incorrectly recognized and the regulation or control intervenes too quickly.

According to a particular embodiment, it is possible for the defined duration to be specified in the control device and/or is or can be specified individually by a user. This measure increases user-friendliness and flexibility.

According to an advantageous development, it can be provided that the defined duration is at least 1 s, preferably at least 100 ms, in particular at least 50 ms. A premature cancellation of the speed reduction by the control device is thus prevented in an advantageous manner. This is associated with an undesired renewed response of the pressure-limiting valve. Build-up with regard to the automatic reduction and increase in engine speed can thus be prevented in a simple manner.

In particular, it can be advantageous if the control device is integrated into a control system which is also set up to reduce the speed of the engine when there is no actuation on the hydraulic rescue tool. As a result, hydraulic power is saved both when the rescue tool is in a resting or idle state and when the rescue tool is operated at its performance limit.

For a better understanding of the invention, it is explained in more detail with reference to the following figures.

Fig. 1

eine Ausführungsform eines tragbaren, akkubetriebenen Hydraulikaggregats in perspektivischer Darstellung;

Fig. 2

eine weitere Ausführungsform eines tragbaren, akkubetriebenen Hydraulikaggregats in Draufsicht;

Fig. 3

ein Schaltplan eines ersten Hydraulikschemas mit einem optischen Bewegungssensor am Druckbegrenzungsventil;

Fig. 4

ein Schaltplan eines zweiten Hydraulikschemas mit einem Hallsensor am Druckbegrenzungsventil;

Fig. 5

ein Schaltplan eines dritten Hydraulikschemas mit einem Amperemeter für den Elektromotor;

Fig. 6

ein Schaltplan eines vierten Hydraulikschemas mit einem Drehzahl- und Drehmomentmessgerät für den Elektromotor;

Fig. 7

ein Schaltplan eines fünften Hydraulikschemas mit einem Durchflussmesser nach dem Druckbegrenzungsventil;

Fig. 8

ein Drehzahl/Druck-Zeitdiagramm.

They each show in a greatly simplified, schematic representation:

1

an embodiment of a portable, battery-powered hydraulic unit in a perspective view;

2

another embodiment of a portable, battery-powered hydraulic unit in plan view;

3

a circuit diagram of a first hydraulic scheme with an optical motion sensor on the pressure relief valve;

4

a circuit diagram of a second hydraulic scheme with a Hall sensor on the pressure relief valve;

figure 5

a circuit diagram of a third hydraulic scheme with an ammeter for the electric motor;

6

a circuit diagram of a fourth hydraulic scheme with a speed and torque meter for the electric motor;

7

a circuit diagram of a fifth hydraulic scheme with a flow meter after the pressure relief valve;

8

a speed/pressure time diagram.

As an introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numbers or the same component designations, it being possible for the disclosures contained throughout the description to be applied to the same parts with the same reference numbers or the same component designations. The position information selected in the description, such as top, bottom, side, etc., is related to the figure directly described and shown and these position information are to be transferred to the new position in the event of a change of position.

1 shows an embodiment of a portable, battery-powered hydraulic unit 1 in a perspective view. The hydraulic unit 1 is connected to a hydraulic rescue tool 4 via a mechanical-hydraulic interface 2, in the case shown via a hydraulic hose connection 3. Two battery packs 5 supply the hydraulic unit 1 with power via an electromechanical interface 6 . An operator 7 handles the hydraulic rescue tool 4 while the hydraulic unit 1 is positioned nearby. Hydraulic unit 1 and rescue tool 4 together form a rescue device 8.

In the 2 a further and possibly independent embodiment of a portable, battery-powered hydraulic unit 1 is shown in plan view. The hydraulic unit 1 is connected directly to a hydraulic rescue tool 4 via a mechanical-hydraulic interface 2 . A battery pack 5 supplies the hydraulic unit 1 with electricity via an electromechanical interface 6 . Hydraulic unit 1 and rescue tool 4 form a one-piece rescue device 8.

The rescue tools 4 can be formed by scissors-like cutting or spreading tools or by combined cutting and spreading tools. Likewise, hydraulic cylinders can function as rescue tools 4 for people who have had an accident, are locked in, or are trapped. Said rescue tools 4 or working elements 10 can also be used by task forces for security operations or to fight crime.

In the 3 a first, simplified circuit diagram with a hydraulic unit 1, an actuating element 9 and a working element 10 is shown. A hydraulic pump 11 is supplied with electricity via an electric motor 12, the electric motor 12 being equipped or connected to a control device 13 or, as in FIG 3 shown, is connected to a control device 13 via a control line 31 . The control device 13 can in turn be part of a control system 14 .

The hydraulic pump 11 conveys a hydraulic fluid 17 in the direction of the working element 10 via a pressure outlet 15 which is connected to a first pressure line 16 . The working element 10 can in particular be a hydraulic rescue tool 4 . Between the hydraulic pump 11 and the working element 10 is the actuating element 9, in the special form shown of a 4/2-way valve 18, positioned. As shown, this actuating element 9 can be constructed outside of the hydraulic unit 1 or it can also be positioned inside the hydraulic unit 1 .

The hydraulic fluid is routed back from the actuating element 9 to the hydraulic tank 21 via a first return line 19 and a return filter 20 . A non-return valve 47 in a bypass line 48 allows, for example if the return filter 20 is clogged, for a brief flow around the return filter 20 in the direction of the hydraulic tank 21.

A mechanical pressure relief valve 22 is connected to the hydraulic pump 11 via the pressure outlet 15 , the first pressure line 16 and a second pressure line 23 . When a maximum pressure preset in the pressure relief valve 22 via a compression spring 24 is exceeded, a piston slide 25 begins to press against the compression spring 24 and thereby displaces a valve body 26. As a result, the hydraulic fluid 17 is routed via the second pressure line 23 through the open pressure relief valve 22 and via a second return line 27 returned to the hydraulic tank 21.

A sensory detection means 28 for detecting the status of the pressure-limiting valve 29 in the special form of an optical movement sensor 30 is shown on the pressure-limiting valve 22 . This optical movement sensor 30 detects the response of the pressure relief valve 22 as a result of the displacement movement of the valve body 26. The signal is transmitted via a control line 31 between the movement sensor 30 and the control device 13. The speed of the electric motor 12 is consequently reduced by the control device 13. This condition lasts as long as the pressure relief valve 22 responds.

In the 4 a second, simplified circuit diagram is shown, with the same reference numerals or component designations for the same parts as in the previous one 3 be used. To avoid unnecessary repetition, reference is made to the detailed description in the previous one 3 pointed out or referred to.

As an alternative to in 3 solution shown is in the 4 a Hall sensor 32 is used as the detection means 28 . This Hall sensor 32 detects the displacement movement of the valve body 26 and subsequently the response of the pressure relief valve 22 as a result of a pressure change. The speed of the electric motor 12 is reduced via a control line 31 between the Hall sensor 32 and the control device 13 . This condition lasts as long as the pressure relief valve 22 responds.

In the figure 5 a third, simplified circuit diagram is shown, with the same reference numerals or component designations as in the previous one being used for the same parts 3 be used. In order to avoid unnecessary repetition, the detailed description in the previous one is also referred to here 3 pointed out or referred to.

As an alternative to in 3 solution shown is in the figure 5 an ammeter 33 is used as the detection means 28 . The motor current is measured via the ammeter 33, which is arranged on the electric motor 12 or on its power supply lines. As a result, the rotation speed of the electric motor 12 is reduced by the control device 13 . This condition lasts as long as the pressure relief valve 22 responds.

6 shows a fourth, simplified circuit diagram, with the same reference numerals or component designations as in the preceding figure for the same parts 3 be used. To avoid unnecessary repetition, reference is made to the detailed description in the previous one 3 pointed out or referred to.

As an alternative to in 3 solution shown in the 6 The speed and torque of the electric motor 12 are measured via a speed measuring device 34 and a torque measuring device 35 . A response of the pressure-limiting valve 22 can be detected by a characteristic change in output via the engine output that can be calculated from this. Subsequently, the speed of the electric motor 12 is reduced by the control device 13 . This condition lasts as long as the pressure relief valve 22 responds.

Also 7 shows a fifth, simplified circuit diagram, with the same reference numerals or component designations as in the preceding figure for the same parts 3 be used. Again, to avoid unnecessary repetition, reference is made to the detailed description in the foregoing 3 pointed out or referred to.

In the second return line 27 there is a detection means 28 for detecting the status of the pressure relief valve 29 in the special form of a flow meter 36 . This flow meter 36 detects the response of the pressure relief valve 22 as a result of a flow of hydraulic fluid 17 through this second return line 27. The speed of the electric motor 12 is reduced via a control line 31 between the flow meter 36 and the control device 13. This condition lasts as long as the pressure relief valve 22 responds.

8 shows a simplified and exemplary speed/pressure time diagram of a possible control scenario. The time axis 38 is shown on the abscissa. The ordinate serves both as a pressure axis 39 and as a speed axis 40. At the beginning of the rescue operation, ie when the hydraulic unit 1 is switched on, the pressure curve 41 and the speed curve 42 rise. In practice, a preferred embodiment is when the pressure profile 41 and the speed profile 42 rise to a defined nominal speed when switched on, so that the operator has the required power available as quickly as possible when starting work with the hydraulic rescue tool 4 . For the sake of simplicity, the representation of 8 However, this approach ramp, which is advantageous in practice, is dispensed with.

If the pressure curve 41 reaches a maximum pressure value 43 preset in the pressure-limiting valve 22, the pressure-limiting valve 22 opens. As a result of this opening, there is no further increase in the pressure curve 41. After a defined period 44, the control device 13 intervenes and reduces the speed to a defined reduction speed 45. If the pressure profile 41 decreases again, for example as a result of a working movement of the rescue tool 4, or if the pressure-limiting valve 22 no longer responds, the speed reduction is canceled again by the control device 13 after a further defined period 46. If work continues to be performed via the rescue tool 4 and pressure is thus reduced, the pressure curve 41 can remain constant as the speed curve 42 increases.

The exemplary embodiments show possible variants, whereby it should be noted at this point that the invention is not limited to the specifically illustrated variants of the same, but rather that various combinations of the individual variants are also possible with one another and that this possibility of variation is based on the teaching on technical action through the present invention in skills of the specialist working in this technical field.

The scope of protection is determined by the claims. However, the description and drawings should be used to interpret the claims. Individual features or combinations of features from the different exemplary embodiments shown and described can represent independent inventive solutions. The task on which the independent inventive solutions are based can be found in the description.

All information on value ranges in the present description is to be understood in such a way that it also includes any and all sub-ranges, eg the information is 1 to 10 to be understood that all sub-ranges, starting from the lower limit 1 and the upper limit 10, are also included, ie all sub-ranges start with a lower limit of 1 or greater and end with an upper limit of 10 or less, eg 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

Finally, for the sake of clarity, it should be pointed out that some elements are shown not to scale and/or enlarged and/or reduced in size for a better understanding of the structure. <b>List of Reference Signs</b> 1 hydraulic unit 29 Pressure relief valve status detection 2 mechanical-hydraulic interface 30 optical motion sensor 3 hydraulic hose connection 31 control line 4 hydraulic rescue tool 32 Hall sensor 5 battery pack 33 ammeter 6 electromechanical interface 34 tachometer 7 operator 35 torque meter 8th rescue device 36 flow meter 9 actuator 37 time monitoring device 10 work item 38 timeline 11 hydraulic pump 39 pressure axis 12 electric motor 40 speed axis 13 control device 41 pressure curve 14 control system 42 speed curve 15 pressure outlet 43 maximum pressure value 16 first pressure line 44 Length of time 17 hydraulic fluid 45 reduction speed 18 4/2 way valve 46 Length of time 19 first return line 47 check valve 20 return filter 48 bypass line 21 hydraulic tank 22 pressure relief valve 23 second pressure line 24 compression spring 25 piston slider 26 valve body 27 second return line 28 detection means

Claims (23)

1. A portable, battery-operated hydraulic unit (1) for hydraulic rescue tools (4), in particular for spreading and/or shearing tools, comprising

   - a control device (13)

   - at least one hydraulic pump (11);

   - at least one first and one second pressure line (16, 23), which are coupled to a pressure outlet (15) of the hydraulic pump (11);

   - a hydraulic tank (21) for a hydraulic fluid (17);

   - at least one battery pack (5);

   - an electromechanical interface (6) for coupling and decoupling, as required, from the at least one battery pack (5);

   - a mechanical-hydraulic interface (2) for connecting the hydraulic rescue tool (4);

   - and at least one electric motor (12) for driving the at least one hydraulic pump (11),
   characterized in that

   a pressure relief valve (22) is formed, which is arranged such that, when a maximum pressure is reached in at least one of the pressure lines (16, 23), the hydraulic fluid (17) is returned to the hydraulic tank (21) via the pressure relief valve (22) and a return line (27) coupled to it,

   and that a pressure relief valve status detection device (29) is configured to detect the response of the pressure relief valve (22),

   and that the control device (13) is configured to reduce the rotational speed of the electric motor (12) as a consequence of the detection of the response of the pressure relief valve (22),

   wherein the control device (13) is configured such that it never reduces the rotational speed of the motor below a defined lower limit value.
2. The hydraulic unit (1) according to claim 1, characterized in that a detection means (28) is formed which is configured to detect the response of the pressure relief valve (22) by detecting the position of a valve body (26).
3. The hydraulic unit (1) according to claim 1, characterized in that a detection means (28) is formed which is configured to detect the response of the pressure relief valve (22) by detecting the power consumption of the electric motor (12).
4. The hydraulic unit (1) according to claim 3, characterized in that a detection means (28) is formed which is configured to detect the response of the pressure relief valve (22) by detecting the motor current.
5. The hydraulic unit (1) according to claim 1, characterized in that a detection means (28) is formed which is configured to detect the response of the pressure relief valve (22) by detecting the torque and the rotational speed of the electric motor (12) and the motor power that can be calculated therefrom.
6. The hydraulic unit (1) according to claim 1, characterized in that a detection means (28) is formed which is configured to detect the response of the pressure relief valve (22) by detecting the flow in the return line (27) downstream of the pressure relief valve (22).
7. The hydraulic unit (1) according to one of the preceding claims, characterized in that a signaling means is formed, which is configured to communicate the reduction of the rotational speed of the motor due to the response of the pressure relief valve (22) to the operator (7) of the hydraulic rescue tool (4) by a signal, preferably by an acoustic, optical and/or haptic signal.
8. A method for operating a portable, battery-operated hydraulic unit (1) for hydraulic rescue tools (4), in particular for spreading and/or shearing tools, wherein the hydraulic unit (1) comprises the following components:

   - a control device (13)

   - at least one hydraulic pump (11);

   - at least one first and one second pressure line (16, 23), which are coupled to a pressure outlet (15) of the hydraulic pump (11);

   - a hydraulic tank (21) for a hydraulic fluid (17);

   - at least one battery pack (5);

   - an electromechanical interface (6) for coupling and decoupling, as required, from the at least one battery pack (5);

   - a mechanical-hydraulic interface (2) for connecting the hydraulic rescue tool (4);

   - and at least one electric motor (12) for driving the at least one hydraulic pump (11),
   wherein

   a pressure relief valve (22) responds when a maximum pressure is reached in at least one of the pressure lines (16, 23), wherein the hydraulic fluid (17) is returned to the hydraulic tank (21) via the pressure relief valve (22) and a return line (27) coupled to it, and that the response of the pressure relief valve (22) is detected by means of a pressure relief valve status detection device (29),

   and that the rotational speed of the electric motor (12) is reduced by the control device (13) as a consequence of the detection of the response of the pressure relief valve (22), wherein the control device (13) never reduces the rotational speed of the motor below a defined lower limit value.
9. The method according to claim 8, characterized in that the response of the pressure relief valve (22) is detected by detecting the position of a valve body (26).
10. The method according to claim 8, characterized in that the response of the pressure relief valve (22) is detected by detecting the power consumption of the electric motor (12).
11. The method according to claim 10, characterized in that the response of the pressure relief valve (22) is detected by detecting the motor current.
12. The method according to claim 8, characterized in that the response of the pressure relief valve (22) is detected by detecting the torque and the rotational speed of the electric motor (12) and the motor power that can be calculated therefrom.
13. The method according to claim 8, characterized in that the response of the pressure relief valve (22) is detected by detecting the flow in the in the return line (27) downstream of the pressure relief valve (22).
14. The method according to one of claims 8 to 13, characterized in that a time monitoring device (37) in the control device (13) detects the duration (44) of the response of the pressure relief valve (22) and the rotational speed of the motor is reduced via the control device (13) as soon as a defined duration (44) of this state is reached or exceeded.
15. The method according to claim 14, characterized in that the defined duration (44) until the reduction of the rotational speed of the motor is predetermined in the control device (13) and/or is predetermined or can be predetermined individually by a user.
16. The method according to claim 14 or 15, characterized in that the defined duration (44) amounts to between 0.5 s and 2 s.
17. The method according to one of claims 8 to 16, characterized in that the control device (13) reduces the rotational speed of the motor by at least 10%, preferably by up to 50%, of the previous rotational speed of the motor.
18. The method according to one of claims 8 to 17, characterized in that the control device (13) cancels the reduction of the rotational speed of the motor as soon as the pressure relief valve (22) no longer responds.
19. The method according to one of claims 8 to 18, characterized in that the control device (13) never lets the rotational speed of the motor drop below 20% of the operating or load speed.
20. The method according to one of claims 8 to 19, characterized in that the control device (13) cancels the reduction of the rotational speed of the motor after a defined duration (46), within which defined duration (46) the pressure relief valve (22) has not responded any more.
21. The method according to claim 20, characterized in that the defined duration (46) is predetermined in the control device (13) and/or is predetermined or can be predetermined individually by a user.
22. The method according to claim 20 or 21, characterized in that the defined duration (46) amounts to at least 1 s, preferably at least 100 ms, particularly preferred at least 50 ms.
23. The method according to one of the preceding claims, characterized in that the control device (13) is integrated in a control system (14) which is further configured to reduce the rotational speed of the motor when there is no manual actuation of a switching or adjusting element (9) on the hydraulic rescue tool (4) or on the hydraulic unit (1) or no manual activation of the hydraulic rescue tool (4).

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