PORTABLE WORKING DEVICE FOR PORTABLE USE

Description

[0001] This application relates to an electromechanical or electrohydraulic tool for portable use, such as a spreading tool, cutting tool, or combination tool with cutting and spreading functions, or a lifting cylinder (or rescue cylinder). The aforementioned tools are preferably used for rescue operations. In particular, the invention relates to a portable tool according to the preamble of patent claim 1. Such a tool is described, for example, in the operating instructions "E-Force 2 Battery-Powered Rescue Equipment," January 1, 2016 (2016-01-01), Weber-Hydraulik GmbH, XP002809161. Technological background

[0002] Portable, motor-driven, electromechanical or electrohydraulic work tools or rescue devices of the type in question here, which can be carried by one operator, are used in a wide variety of applications. For example, there are spreading tools, cutting tools or so-called combination tools, i.e. tools with cutting and spreading functions and rescue cylinders, which are used by emergency services (fire departments), for example, to rescue injured people from accident vehicles or to free earthquake victims. The type of work tools or rescue devices is diverse. There are electrohydraulically or electromechanically driven work tools or rescue devices with, preferably hardened, tool inserts for cutting, spreading or pressing. Such devices are exposed to extremely high mechanical demands in use and, depending on the location, are subjected to a wide variety of environmental influences (heat, cold, humidity).

[0003] It is particularly important that rescue equipment in particular ensures a particularly high level of operational reliability, as rescue operations must always be carried out quickly and unexpected operational failures can therefore have fatal consequences.

[0004] Furthermore, such tools are exposed to increasingly greater mechanical stress over time during use. This is due to the fact that, for example, in the automotive industry, increasingly high-strength materials are being used which have to be cut through by a cutting tool. But operating such tools also requires a lot of experience. For example, if a cut is made on the B-pillar of a car using a cutting tool, the two cutting edges of the cutting tool initially penetrate the material quickly. The cutting process then slows down and comes to a standstill. If sufficient force is applied to the cutting tools, microcracks form which migrate through the material. These microcracks cannot be seen with the naked eye. Inexperienced operators think the tool has reached its performance limit, put the cutting tool down in this situation and then start the cut again.In such a situation, an experienced operator, on the other hand, will wait a certain amount of time, maintaining the full load of both cutting edges on the material to be cut. During this time, the microcracks continue to propagate until the material finally tears off due to the applied load from the cutting edges, causing the microcracks to propagate and resulting macrocracks. On the other hand, a situation may also arise in which the material to be cut is actually too hard, and waiting too long at full load will not result in the desired separation of the material. Therefore, detecting these situations has been difficult until now.

[0005] Another problem with such devices is that the opening and closing times of the tools in question can be very long, depending on the situation. For example, a rescue ram is 40 cm long when retracted and 150 cm long when extended. As a result, it can take a relatively long time for the piston of the rescue ram to extend to the required length. Since rescue operations always involve carrying out a rescue operation as quickly as possible, there is an urgent need to keep the opening and closing times of tools with a movable piston rod as short as possible.

[0006] Although electrohydraulic implements feature hydraulic proportional valves, these have only a minor impact on the opening and closing times of the implement. Printed state of the art

[0007] WO 2012 / 019758 A1 describes a control device for a first and second implement, in which the delivery capacity of two pumps connected in parallel is controlled via a single hydraulic control valve, whereby the delivery capacity of the two pumps is available either exclusively to a first pressure line or exclusively to a second pressure line, or to the first and second pressure lines together in a specific ratio. The selection is made via the respective position of the hydraulic control valve.

[0008] WO 2013 / 127452 discloses a method for operating a hydraulic pump assembly, in which a load-dependent control is performed as a function of the motor current, such that switching from a load state to a non-load state and vice versa takes place depending on the current. This method serves to save energy and thus conserve battery life. Object of the present invention

[0009] The object of the present invention is to improve the operational effectiveness of a generic hydraulic pump arrangement for a working device for portable use. Solution to the task

[0010] The above object is achieved by the features of claim 1. Advantageous embodiments of the present invention are claimed in the further claims.

[0011] According to the invention, the electronic control and regulation unit defines, in addition to a first operating state in which the electric motor is operated at a first frequency F1, a second operating state in which the electric motor is operated at a second frequency F2, wherein the operating state can be switched between the first and second operating states by the operator of the implement by means of manually operable switching means and wherein the speed of the electric motor is higher at the second frequency F2 than at the first frequency F1. As a result, the piston rod can be extended or retracted considerably more quickly when required by switching to the second frequency F2 than with previous implements. This makes it possible to dispense with an arrangement comprising two separate pumps connected in parallel, each of which must be driven by associated electric motors.The function of switching the electric motor to the second frequency F2 (turbo mode) can be easily implemented in a portable, battery-powered tool. The selected frequency determines the speed of the electric motor and is freely selectable. The higher the frequency, the faster the electric motor rotates to drive a downstream mechanism or a downstream hydraulic pump. According to the invention, the electric motor is a brushless DC motor (or "electronically commutated motor" or "ECM" or "EC motor"). According to the invention, the tool according to the invention comprises a display device that includes a temperature display that shows the current operating temperature range of the semiconductor components.The temperature display gives the operator an indication of the temperature range of the semiconductor module, in particular of the range of a possible overall range in which the current operating temperature is located.

[0012] Switching from the first frequency F1 to the second frequency F2 is expediently only possible within a subset of the electric motor's overall power range. In particular, with electro-hydraulic tools, switching to the second operating mode is no longer possible above a predetermined pressure (e.g., 500 bar). This prevents mechanical problems in the hydraulic circuit.

[0013] Preferably, switching takes place between constant frequencies F1 and F2.

[0014] It is advisable to make switching from the first frequency F1 to the second frequency F2 dependent on the power requirement. For example, a power requirement threshold SW can be specified, above which switching from the first frequency F1 to the second frequency F2 or operation of the work tool at the second frequency F2 is no longer possible. This measure serves to perform a plausibility check to determine whether an operating state exists in which active work is being carried out (cutting, spreading, or pressing) or in which the tools are merely being opened or closed. If the cutting tool of the work tool has already penetrated the material, for example, switching from the first frequency F1 to the second frequency F2 is not possible.

[0015] Because a hydraulic control valve (hydraulic multi-way valve) is provided for switching the direction of movement of the piston rod, and the operating state is also switched between the first and second operating states when the control valve is actuated, the intuitive use of the tool is maintained for the operator, which is advantageous for rescue operations. The operator only switches the control valve with regard to the direction of movement of the piston rod and the operating state of the electric motor. The operator operates the rescue tool as usual. There is only one additional operating function on the otherwise unchanged control valve.

[0016] If the control valve is a rotary valve, which in particular comprises a ring-shaped handle or star handle, the switching of the operating state between the first and second operating states can be triggered by simply rotating the control valve by an additional angular range Δα to the actual angular range of the control valve actuation. Thus, to switch the electric motor from the first to the second operating state, the operator simply rotates the rotary valve by the additional angular range Δα.

[0017] The control valve is advantageously a so-called proportional valve, in which the transitions between the valve positions are continuous, allowing variable flow rates to be achieved. The switching option from the first to the second operating state according to the invention is superimposed on the proportional valve and is comparable to a type of "kick-down" function.

[0018] By recording the heat W generated during operation by the current A drawn by the electric motor and using it as a control variable, the invention effectively prevents harmful effects due to excessively prolonged overload operation. At the same time, the operator can also "push to the limit" more effectively than before without constantly having to consider whether the current operating condition is still on this side of or already beyond the load limit. Individual experience levels of operators are thus irrelevant. The chances of success of an operation increase. The operational effectiveness of the hydraulic pump arrangement of this type is thus significantly improved.

[0019] Preferably, the heat W generated during operation by the current drawn by the electric motor is detected in or at least in the local area of ​​the electronic control and regulation unit, particularly in the area of ​​the circuit board or semiconductor components (e.g., in the area of ​​the IGFETs or MOSFETs). This is where the heat W generated during operation by the current A drawn by the electric motor is generated and can therefore be detected particularly well.

[0020] To detect the heat W or the temperature or the temperature rise, a first temperature sensor can be provided which detects the heat W generated during operation by the current drawn by the electric motor and transmits it to the electronic control and regulation unit. This can be an electrical or electronic component that delivers an electrical signal as a measure of the temperature. In particular, it can be components that change their resistance when the temperature changes (e.g. PTCs, NTCs) or components that directly deliver a processable electrical signal (e.g. integrated semiconductor temperature sensors (solid-state circuits) or use the temperature dependence of the base-emitter voltage of a transistor connected as a diode.

[0021] The electric motor can in particular be designed in such a way that the speed of the electric motor remains, at least substantially, constant during operation when a load occurs and only the current drawn by the electric motor increases when a load occurs.

[0022] Furthermore, according to the invention, the ambient temperature T at the working device can be additionally recorded and included in the control. This allows, in particular, the sum or, if necessary, the ratio of heat W generated during operation by the current A drawn by the electric motor and the ambient temperature T at the working device to be additionally used for control purposes. This is advantageous because the ambient temperature has an additional influence on the heat development of the semiconductor components and, moreover, heat development can begin with a time delay during a switching operation due to the current A drawn by the electric motor. With additional recording of the ambient temperature, heat development can thus be recorded even more precisely.

[0023] The hydraulic pump arrangement expediently includes a second temperature sensor for detecting the ambient temperature T. This can be an electrical or electronic component that provides an electrical signal as a measure of the temperature. In particular, it can be components that change their resistance when the temperature changes (e.g., PTCs, NTCs) or components that directly provide a processable electrical signal (e.g., integrated semiconductor temperature sensors (solid-state circuits) or utilize the temperature dependence of the base-emitter voltage of a transistor connected as a diode).

[0024] The control system can limit the current A drawn by the electric motor and / or completely shut down the electric motor. In both cases, this measure reduces overheating and thus effectively protects the operation of the implement.

[0025] The switching process that limits the current A drawn by the electric motor and / or shuts down the electric motor is preferably carried out taking into account a time delay t. This is advantageous because it can prevent delayed overheating.

[0026] To determine or determine the time delay t, the ambient temperature T can also be used.

[0027] Preferably, the working device according to the invention comprises a display device, which in turn comprises the following: a load indicator showing the power of the implement on the basis of the current A drawn by the electric motor during operation, and / or an operating status indicator showing which operating status the implement is in or whether the implement is in the second operating status, and / or a full-load operating status indicator showing that a full-load duration has been exceeded.

[0028] The load indicator shows the operator whether the implement is in a state where additional load can be generated or whether it is operating at full load. The load indicator can be implemented, for example, as a light bar arrangement. The operating status indicator tells the operator whether the implement is in the first or second operating mode. The full load operating status indicator shows that a full load duration has been exceeded, allowing the operator to interrupt operation, for example, to reposition the implement.

[0029] Preferably, the load indicator can include a warning mode that indicates that the work tool is currently in the overload range. This alerts the operator that the work process should be aborted. This significantly increases operational efficiency.

[0030] The work equipment should conveniently include the following: a hydraulic pump, a hydraulic tank, a piston rod, a hydraulic cylinder for receiving the movable piston rod, hydraulic lines and / or a compensation device. Description of the invention using exemplary embodiments

[0031] A practical embodiment of the present invention is described in more detail below. For the sake of clarity, recurring features are provided with a reference numeral only once. They show: Fig. 1 shows an overall view of a working device in the form of an electro-hydraulic, battery-operated cutting device; Fig. 2 shows an example of a hydraulic circuit diagram of the cutting device according to Fig. 1 ; Fig. 3 a highly simplified schematic representation of the essential components of the overload protection of the working device according to Fig. 1 ; Fig. 4 a highly simplified schematic representation of the functional switching positions of the control valve of the implement according to Fig. 1; Fig. 5 a flow chart for controlling the engine power of the implement according to the Fig. 1 and 2 ; Fig. 6 a comparative illustration of the heating of the electronics of the working device after Fig. 1 at different ambient temperatures; and Fig. 7 an example of a display device for the performance of the working device according to Fig. 1 .

[0032] Reference number 1 in Fig. 1 refers to the tool according to the invention in its entirety. In the embodiment according to Fig. 1is the working device 1, e.g., an electro-hydraulic, battery-operated cutting device (cutter). The working device 1 comprises a housing 12 containing an electric motor 3, a hydraulic pump 2, and a hydraulic tank 19. Furthermore, a compensating device 17 is provided for volume compensation of the hydraulic fluid during operation of the working device 1. This can be, for example, a flexible membrane or the like. Attached to the housing 12 are a display 14 and an on / off switch 13. The operating states can be read by the operator on the display 14.

[0033] At the front of the working device 1 there are two tool halves 11a, 11b, which in the Fig. 1 shown embodiment are cutting tool halves. The two cutting tool halves 11a, 11b are connected via a (in Fig. 1not shown) piston rod. The latter is located in a hydraulic cylinder (also not shown). The hydraulic cylinder is located below a Fig. 1 visible cover 28, in the area of ​​which a first handle 15 is located. A second handle 16 is provided on the housing 2. The working device 1 can thus be guided or operated by the operator with two hands. On the back of the housing 12 is a (in Fig. 1 not visible) insertion slot for a battery. Via a hydraulic valve 6, the operator can manually control the direction of the hydraulic flow with the hand on the second handle 16, so that the piston rod is either retracted (closing the tool halves 11a, 11b) or extended (opening the tool halves 11a, 11b) or hydraulic oil is returned to the supply circuit (bypass operation). Fig. 1The design of the control valve 6 shown is a control valve that can be rotated in the extension of the axis of the handle 16 and has a so-called star handle, which is rotated by the operator to control the switching positions.

[0034] The work equipment in question here is capable of being operated in any spatial arrangement or orientation.

[0035] In addition to the cutting device described above, the invention can also include a spreading device, a combination device with cutting and spreading functions, or a lifting or rescue cylinder. All of these devices utilize a piston rod guided in a cylinder, e.g., a hydraulic cylinder.

[0036] Fig. 2 shows an example of a hydraulic circuit diagram of the working device according to Fig. 1. The pump 2 is, for example, a piston pump with, for example, four cylinders, two cylinders for high pressure (HD) and two cylinders for low pressure (LP). The respective second branch (HD, LP) is pressurized with a time delay to the first branch in order to generate high pressure (HD) or low pressure (LP). The pistons of the pump are driven by the electric motor 3. Hydraulic fluid is kept ready in a hydraulic tank 19, on which a compensation device 17 for volume compensation of hydraulic fluid during operation, for example in the form of a flexible diaphragm, can be provided. Each HD and LP output of the pump 2 is connected to the control valve 6, which is, for example, a multi-way valve with three switching positions, and to a controllable relief valve 27a, 27b. Each relief valve 27a, 27b is connected to the inlet side of the control valve 6 via a control line 23a, 23b.

[0037] At the Fig. 2 left switching position of the control valve 6, pressure (HD or ND) is built up in the area of ​​the side of the hydraulic cylinder 4 facing away from the piston rod 5, whereby the piston rod 5 is extended, whereas in the Fig. 2 In the switching position of the control valve 6 shown on the right, a corresponding pressure is built up on the opposite side of the hydraulic cylinder 4, so that the piston rod 5 is retracted. The hydraulic fluid displaced by this actuation is fed back into the hydraulic tank 19 via the tank line 33.

[0038] The center position of the control valve 6 represents the position in which hydraulic fluid is pumped in bypass operation without the piston rod 5 being moved.

[0039] If, for example, pump 2 is operated in high-pressure mode, the working pressure is divided at a first node 24a towards control valve 6 and the controlled relief valve 27a. When high pressure (HP) is applied, relief valve 27a is closed via control line 23a. A control pressure is applied to relief valve 27b via a further control line 23b. The flow rate of the low-pressure elements (LP) is also divided at a second node 24b and is directed towards control valve 6 and relief valve 27b. If the control pressure at relief valve 27b is now higher than the pressure of the low-pressure elements, relief valve 27b is opened and the flow rate of the low-pressure elements is returned to tank 19.

[0040] Alternatively, if pump 2 is operated in low-pressure mode, the control pressure at relief valve 27b cannot work against the flow of the low-pressure elements. Both flow rates (high and low pressure) are directed toward control valve 6.

[0041] A load-holding element 26 is located between control valve 6 and hydraulic cylinder 4. The load-holding element 26 comprises intersecting control lines. For example, if pressure from pump 2 is present in the left switching position of control valve 6, the check valve 25 of the load element 26 is opened via one of the two control lines, allowing hydraulic fluid to flow back. The same applies to the right switching position of control valve 6, only in the opposite direction.

[0042] The control valve 6 is manually operated using a handle and is spring-loaded. The spring force for both the left and right positions of the control valve 6 must be overcome via the handle of the control valve 6. As soon as the handle is released, the control valve 6 automatically returns to its initial position (center position). The control valve can expediently be a so-called proportional valve, in which the line cross-section for the hydraulic fluid is continuously increased or reduced, i.e., there are no abrupt transitions. Check valves 25 are located between the hydraulic pump 2 and the control valve 6.

[0043] The electric motor 3 is in particular a so-called brushless DC motor, the speed of which can be controlled or regulated via a control and regulating unit.

[0044] Fig. 3shows a highly simplified schematic representation of the essential components of an overload protection device for the work tool 1. The components such as hydraulic cylinder 4, piston rod 5, control valve 6, pump 2, electric motor 3 and battery 18 are shown in a simplified manner. In Fig. 3 For the sake of clarity, only a single pump symbol is used for pump 2. Hydraulic return lines to the tank are not shown for the sake of clarity.

[0045] To operate the electric motor 3, a control and regulation unit 7 is provided, which has the display 14. The control and regulation unit 7 is connected to the electric motor 3 via a control line 32 and to the control valve 6 via a control line 31. The control and regulation unit 7 comprises a microcontroller 20 and a frequency converter 21. The control and regulation unit 7 or the microcontroller 20 can comprise a memory (not shown). Furthermore, the control and regulation unit 7 comprises a current detector 22, with which the current drawn by the electric motor 3 can be detected.

[0046] The battery 18 housed in the implement provides the electrical energy for the electric motor 3 in the form of voltage and current. The voltage decreases as the battery discharges. The electrical energy is fed into the frequency converter 21, which comprises a plurality of so-called MOSFETs. These are electronic switches that have a specific electrical resistance. The task of the frequency converter 21 is to convert the direct current from the battery 18 into three-phase current. The three-phase current is characterized by a voltage, a current, and a frequency. The frequency determines the speed of the electric motor 3. The higher the frequency, the faster the electric motor 3 rotates. The voltage remains essentially constant. Since a faster-rotating motor requires more energy, a correspondingly higher power requirement arises as the motor speed increases.This, in turn, results in a power loss that increases the higher the electrical current drawn by the electric motor 3. The power loss is converted into heat and heats the MOSFETs of the frequency converter 21.

[0047] The electronic control and regulation unit 7 of the electric motor 3 establishes a first operating state in which the electric motor 3 is operated at a first frequency F1 or speed. In addition, the electronic control and regulation unit 7 establishes a second operating state in which the electric motor 3 is operated at a second frequency F2, whereby the speed of the electric motor is higher at the second frequency F2 than at the first frequency F1. Furthermore, manually operable switching means are provided that enable the operator of the work device 1 to switch between the first and second operating states. This allows a type of turbo function in the sense of a "kickdown" to be realized during operation, in which the piston rod 5 of the hydraulic cylinder 4 can be moved particularly quickly in order to bring the tools into the working position as quickly as possible.For example, a rescue ram can be very quickly moved from a retracted position with a length of, say, 40 cm to an extended position with a length of, say, 150 cm. Located in the area of ​​the frequency converter 21 is a first temperature sensor 8, which detects the heat, i.e., heat loss, in the area of ​​the frequency converter 21 or the MOSFETs located therein and feeds this information into a control process.

[0048] Furthermore, the control and regulation unit 7 comprises a second temperature sensor 9, which is intended to measure the ambient temperature, which can also be included in the control process. The second temperature sensor 9 can be positioned in the region of an opening (not shown) in the housing 2. The temperature sensors are preferably components that change their resistance when the temperature changes (e.g., PCTs, NTCs), or components that directly deliver a processable electrical signal (such as integrated semiconductor temperature sensors (solid-state circuits) or utilize the temperature dependence of the base-emitter voltage of a transistor connected as a diode).

[0049] The display 14 comprises a display device 10, which in turn may comprise, for example, a load display 10a and / or operating status display 10b and / or temperature display 10c, see also Fig. 7 .

[0050] The control and regulation unit 7 and the display 14 are preferably arranged on a common circuit board 28. However, they can also be arranged on separate circuit boards.

[0051] The control and regulation unit 7 is connected to the control valve 6 via the control line 31. The purpose of this measure is to allow the operator not only to control the direction of movement of the piston rod (extension, retraction, or bypass position) via the control valve 6, but also to switch the operating state between the first and second frequency F1 or F2 via a control signal triggered by the control valve 6. The operator can thus activate or deactivate the turbo function of the implement 1 at any time during operation without releasing the control valve 6.

[0052] In Fig. 4The various switching positions of the control valve 6 of the working device 1 are shown as examples in a simplified schematic representation. In the case of the control valve 6 in Fig. 4 only the actuating element is shown, which in this special case is a so-called rotating star handle 29. In the Fig. 4 In the position of the star grip 29 shown, the control valve 6 is in its central position, in which the piston rod 5 is neither extended nor retracted, but hydraulic fluid is simply returned to the tank via the respective relief valve 27a, 27b without the piston rod 5 being moved. If the star grip 29 is now rotated by an angle of e.g. 10° to the left in Fig. 4 turned, the control valve 6 is, for example, in the position shown in Fig. 2 If the star grip 29 is turned 10° to the right, the control valve 6 is moved to the position shown in Fig. 2right switching position. The switching of the electric motor from the lower frequency F1 to the higher frequency F2 is also carried out by actuating the star grip 29. Preferably, the star grip 29 can be rotated, for example, over an angular range of 20° in order to additionally activate the turbo function when retracting or extending the piston rod 5. This makes the use of the working device 1 particularly easier. As soon as the operator releases the star grip 29 in the deflected position, the latter is due to spring force in the Fig. 4 The starting position shown is rotated back. If the star grip 29 is simply rotated back to the angular range of 10°, the turbo function is deactivated during the retraction or extension of the piston rod 5. A switching point that can be overcome by force can be provided between the angle or angular range of the normal function and the angle or angular range of the turbo function.

[0053] The following is based on Fig. 5 The control of the turbo function and the overload protection are explained in more detail. The following parameters are predefined for control: - N0 = the lower limit speed (speed without turbo function) - Nmax = the upper limit speed (maximum speed with turbo function) - N = the precisely measured, current speed of the system - N / a = the last measured speed stored in memory - Imax = the maximum current drawn by the electric motor - Tmax = the maximum temperature in the area of ​​the first temperature sensor

[0054] First, the last measured speed Na is set to the lower limit speed N0 in a first step S1. In a step S2, the current speed N, the current current I, and the current temperature in the area of ​​the first temperature sensor 8 are measured. In a verification step S3, it is checked whether the turbo function is activated or not. If the turbo function is not activated, the parameters N, I, and T are measured again after a certain time (step S8) (step S2).

[0055] If, on the other hand, the turbo function is activated, a further step S4 measures whether the current speed N is less than Nmax, the measured current I is less than Imax and the measured temperature T is less than Tmax. If these relationships are met, a further step S5 checks whether the measured speed is less than a defined speed threshold below Nmax. If this is the case, the speed is increased by a certain amount in a further step S6 and, after a certain waiting time (step S7), the measurement of N, I and T is carried out again (step S2).

[0056] If the condition in step S4 is not met, a further step S9 determines whether the measured speed N is greater than N0+x, where x is the size of a speed (e.g. 100). If this is the case, in step S11 the last measured speed is reduced by the speed x (e.g. 100) and stored in the memory as Na, a certain period of time is waited for (step S13) and then measured again (step S2). If the condition in step S9 is not met, the lower limit speed N0 is written into the memory as the last measured speed. The speed cannot be reduced any further. In this case, a warning is output in step S12 stating that the drawn current I and / or the measured temperature T are too high.

[0057] Preferably, within the scope of the control system, an automatic switchover from the second operating state of the higher frequency F2 to the first operating state of the lower frequency F1 occurs. This switchover can preferably take place taking into account a time delay t, for example by switching off the turbo mode before the parameter Tmax has been reached.

[0058] The ambient temperature should preferably be taken into account when controlling the electric motor, since the ambient temperature, in conjunction with the heat generated by the power loss of the MOSFETs, reaches different values ​​depending on the ambient temperature, as shown in Fig. 6 For example, at an ambient temperature of 30°C, the control and regulation unit 7 must intervene considerably earlier than at an ambient temperature of 10°C, as can be seen from Fig. 6The switching times must be selected taking into account a time delay tx, such that even after a shutdown, the system can still heat up slightly due to its thermodynamic inertia without exceeding the maximum temperature. A corresponding time delay is Fig. 6 also visible.

[0059] Fig. 7shows part of the display device 10 of the work device 1 according to the invention. The display device 10 comprises a power display device 10a, which has a plurality of fields that show the current power in the manner of a bar chart. In addition to the bars that are displayed by illumination and / or color, a numeric number that shows the current power value in percent can also be displayed in the respective segment of the bar display. For example, the range 25 corresponds to a pressure of 175 bar, the range 50 to a pressure of 350 bar, the range 75 to a pressure of 525 bar, and the range 100 to a pressure of 700 bar.

[0060] As part of the control of electric motor 3, an additional function is provided that indicates to the operator when a processing step, e.g., a cut, should be aborted. This can be conveniently achieved by having the power indicator show 100% power during full-load operation, with the 100% indicator starting to flash after a certain time. This signals the operator to start a new processing cycle.

[0061] Additionally, an operating status indicator 10b can be provided on the display device 10, which indicates whether turbo mode is activated or not. Additionally or alternatively, a temperature indicator 10c, for example in the form of an alphanumeric display or a bar graph, can also be provided. LIST OF REFERENCE SYMBOLS

[0062] 1Working device 2Hydraulic pump 3Electric motor 4Hydraulic cylinder 5Piston rod 6Control valve 7Control and regulation unit 8First temperature sensor 9Second temperature sensor 10Display device 10aLoad indicator 10bOperating status indicator 10cTemperature indicator 10dDisplay device 11Tool halves 12Housing 13On / off switch 14Display 15First handle 16Second handle 17Compensation device 18Battery 19Hydraulic tank 20Microcontroller 21Frequency converter 22Current detector 23aControl line 23bControl line 24aFirst node 24bSecond node 25Check valve 26Load-holding element 27aRelief valve 27bRelief valve 28PCB 29Star grip 30aSafety valve 30bSafety valve 31Control line 32Control line 33Tank line A Drawn current F1 Frequency F2 Frequency HD High pressure ND Low pressure t Time delay TAmbient temperature SW Current demand threshold

Claims

1. Portable implement (1), such as for example an expander, cutter or combination device with a cutting and expanding function, for portable use, having an electric motor (3), a battery (18) accommodated on the implement (1), a mechanically or hydraulically driven displaceable piston rod (5) for performing work, in particular expanding work and / or cutting work and / or lifting or compressing work, an electronic control and regulation unit (7) for controlling and / or regulating the electric motor (3), as well as semiconductor components, characterized in that provision is made for a brushless DC motor as electric motor (3), wherein the electronic control and regulation unit (7) defines a first operating state in which the electric motor (3) is operated at a first frequency F1, the electronic control and regulation unit (7) defines a second operating state in which the electric motor (3) is operated at a second frequency F2, wherein it is possible for the operator of the implement (1) to switch the operating state between the first and second operating state by way of manually operable switching means of the portable implement (1), wherein the speed of the electric motor (3) at the second frequency F2 is higher than at the first frequency F1, and wherein provision is made for a display apparatus (10) that comprises a temperature display (10c) that shows the range in which the current operating temperature of the semiconductor components is located.

2. Implement according to Claim 1, characterized in that it is possible to switch from the first frequency F1 to the second frequency F2 only in a subregion of the overall power spectrum of the electric motor (3).

3. Implement according to Claim 1 or 2, characterized in that the speed of the electric motor (3) at the first frequency F1 and second frequency F2 is constant in each case.

4. Implement according to at least one of the preceding claims, characterized in that a current demand threshold value SW is predefined, above which it is not possible to switch from the first frequency F1 to the second frequency F2 or to operate the implement at the second frequency F2.

5. Implement according to at least one of the preceding claims, characterized in that provision is made for a control valve (6) for switching the direction of movement of the piston rod and the operating state is also switched between the first and second operating state when the control valve (6) is actuated.

6. Implement according to Claim 5, characterized in that the control valve (6) is a rotary valve and the switching of the operating state between the first and second operating state is triggered by rotating the control valve (6) about an additional angular range Δα.

7. Implement according to at least one of the preceding claims, characterized in that the heat W produced during operation by the current A drawn by the electric motor (3) is detected and additionally used as a control variable.

8. Implement according to at least one of the preceding claims, characterized in that the heat W produced during operation by the current drawn by the electric motor (3) is detected in the local region of the electronic control and regulation unit (7).

9. Implement according to at least one of the preceding claims, characterized in that provision is made for a first temperature sensor (8) that detects the heat W produced during operation by the current drawn by the electric motor (3).

10. Implement according to at least one of the preceding claims, characterized in that the ambient temperature T is detected and jointly incorporated into the control.

11. Implement according to at least one of the preceding claims, characterized in that provision is made for a second temperature sensor (9).

12. Implement according to at least one of the preceding claims, characterized in that the electric motor (3) is controlled on the basis of the drawn current A, of the heat W produced by the current A drawn by the electric motor (3) and / or ambient temperature T.

13. Implement according to at least one of the preceding claims, characterized in that automatic switching from the second to the first operating state or deactivation takes place in the course of the control.

14. Implement according to Claim 13, characterized in that the switch takes place with consideration of a time delay t.

15. Implement according to at least one of the preceding claims, characterized in that provision is made for a display apparatus (10) that comprises the following: a load display (10a), in which the power of the implement is displayed on the basis of the current A drawn by the electric motor (3) during operation, and / or an operating state display (10b) that shows that the implement is in the second operating state, and / or an operating state display that shows that the duration of maximum power is exceeded.

16. Implement according to Claim 15, characterized in that the load display (10a) has a warning mode that indicates that the implement (1) is in the overload range and the operating process must be interrupted.

17. Implement according to at least one of the preceding claims, characterized in that the implement (1) comprises the following: a hydraulic pump (2) and / or a hydraulic tank (19) and / or a piston rod (5) and / or a hydraulic cylinder (4) for receiving the displaceable piston rod (5) and / or hydraulic lines and / or an equalization apparatus (17).