EP3478452A1

EP3478452A1 - Method for operating a hydraulically operated handheld device, and hydraulically operated handheld device

Info

Publication number: EP3478452A1
Application number: EP17730729.5A
Authority: EP
Inventors: Egbert Frenken
Original assignee: Gustav Klauke GmbH
Current assignee: Gustav Klauke GmbH
Priority date: 2016-06-29
Filing date: 2017-06-08
Publication date: 2019-05-08
Anticipated expiration: 2037-06-08
Also published as: US11612990B2; KR20190022823A; US20200147772A1; CN109562508A; WO2018001691A1; KR102380705B1; CN109562508B; DE102016111874A1; EP3478452B1; AU2017290411B2; AU2017290411A1

Abstract

The invention relates to a method for operating a hydraulically operated handheld device (1), for example a pressing device and/or a hole-punching or punching device. In order to specify a method for operating a hydraulically operated handheld device which, with a simple structure of the device, allows workpieces that differ in particular in terms of size and/or material to be machined and simplifies handling, it is proposed that the hydraulic pressure, acting on the return valve (8), for triggering a movement of the moving part (4) into the end position be increased by a separately triggerable pressure increase, resulting in the opening of the return valve (8), in a hydraulic medium volume located upstream of the valve seat of the return valve (8) in a direction of flow of the hydraulic medium upon travelling into the end position. The invention also relates to a corresponding hydraulically operated handheld device.

Description

description

Method for operating a hydraulically operated hand-held device and hydraulically operated hand-held device

Field of engineering

The invention relates first to a method for operating a hydraulically operated hand-held device, for example. A pressing device and / or a punching or punching device, wherein the handset comprises a hydraulic pump, a moving part, a fixed part and a return valve with an associated valve seat, said Further, the moving part by building a hydraulic pressure, which results by filling a hydraulic space with hydraulic fluid from a storage space using the hydraulic pump, is moved to a working position, which can be reached that the moving part upon reaching a predetermined working pressure by opening the return valve automatically off the working position is moved back to an end position.

In addition, the invention relates to a hydraulically operated hand-held device, such as pressing device or punching or punching device, wherein the handset comprises a hydraulic pump, a moving part, a fixed part and a return valve with an associated valve seat, wherein further the moving part by building a hydraulic pressure, which is achieved by filling a hydraulic space with hydraulic fluid from a storage space using the hydraulic pump is movable in a working position, it being achievable that the moving member is automatically moved on reaching a predetermined working pressure by opening the return valve from the working position to an end position , State of the art

Such methods and hand-held devices are known, for example, from DE 10 2008 028 957 A1, EP 0 944 937 B1 (US Pat. No. 6,276,186 B1, US Pat. No. 6,401,515 B2) and WO 2014/108361 A1.

[0004] Such handheld devices are used, for example, as pressing devices, preferably for pressing or crimping cable lugs with a cable inserted or for pressing tubular or tubular workpieces. Also, such handsets can be used for punching or punching in particular of metal components. Furthermore, such handheld devices can also be designed as riveting devices or other cutting devices. A hydraulically operated hand-held device in the form of a pressing device is described, for example, in EP 0 944 937 B1 (US Pat. No. 6,276,186 B1, US Pat. No. 6,401,515 B2). This handset has a return valve, which is displaced upon reaching a predetermined hydraulic pressure in a valve open position and held in this position. This leads to a backflow of the hydraulic part displacing the movement part into the working position. The moving part moves back into the basic or end position due to the missing or reduced pressure. At the latest when this end position is reached, the hydraulic pressure acting on the return valve is lowered in such a way that the return valve automatically closes again.

Summary of the invention Starting from the illustrated prior art, the invention has the object to provide a method for operating a hydraulically operated hand-held device or a hydraulically operated hand-held device, which with a simple structure of the device processing in particular with respect to size and / or material of different workpieces allows or simplifies handling.

A possible solution is given according to a first inventive concept in a method in which it is geared to the fact that acting on the return valve hydraulic pressure to trigger a movement of the moving part in the end position by a separately triggered, leading to the opening of the return valve pressure increase in is increased in the flow direction of the hydraulic fluid in the process in the end position in front of the valve seat of the return valve hydraulic fluid volume. With regard to the hydraulically operated handset in this regard it is aimed that the force acting on the return valve hydraulic pressure to trigger a movement of the moving part in the end position by a separately triggerable, leading to the opening of the return valve pressure increase in a flow direction of the hydraulic fluid in the process in the end position in front of the valve seat of the return valve located hydraulic fluid volume can be increased.

In a further solution of the problem is based on the fact that acting on the return valve hydraulic pressure lowered by a separately triggerable, leading to the closing of the return valve pressure reduction located in the flow direction of the hydraulic fluid in the process in the end position in front of the valve seat of the return valve hydraulic fluid volume is or is lowerable.

The features of the above-described independent claims are essential to each other, as well as in any combination with each other, wherein features of an independent claim with the features of another independent claim or can be combined with features of several independent claims, further with only individual features of one or more of the further independent claims.

The predetermined working pressure is the adjusting itself by a work in the hydraulic fluid hydraulic pressure, wherein the return valve moves due to its structural design in the open position. This hydraulic pressure is established when the return valve is closed in the hydraulic chamber, which extends from the moving part to a closing surface of the return valve. The structural design is preferably given by the fact that a partial piston surface of a valve piston with a certain force, for example achieved by a spring acting on the valve piston in the closed state with a certain force, is seated in the valve seat in the closed state, thus forming said closure surface. A certain hydraulic pressure is then required in order to lift the return valve out of the valve seat by acting on this partial piston surface so that hydraulic fluid, for example into a hydraulic fluid reservoir, can drain through the valve seat. The return valve is further preferably designed as a valve piston, that it has an overall piston surface on which the hydraulic fluid acts when the return valve is lifted from the valve seat, that is in the open position. Due to the size ratio between the total piston area and the partial piston area, a comparatively very low pressure of the hydraulic medium may be sufficient in the open position of the return valve relative to the partial piston area in order to hold the return valve in its open position. The surface which supplements the partial piston surface to the total piston surface, can also be acted upon by hydraulic means in the closed state of the return valve. However, not by the hydraulic means, which is contained in the hydraulic space ending at said closure surface, and thus in the flow direction of the hydraulic medium in the process in the end position before the return valve is, but for example by a separate hydraulic fluid volume. In a practical design, for example, with respect to the partial piston surface, a pressure of 300 to 600 bar, further example, 400 or 500 bar, be required to lift the return valve from the valve surface, while the total piston area only a pressure of a few, for example, 5, 4th or less bar, up to about 0.5 bar, for example, to stay in the open position. This acting on the entire piston surface pressure can be generated in a specific embodiment, for example, by acting on the moving part return spring.

The predetermined working pressure can also be adjustable as such or be provided adjustable, for example by adjusting the force acting on the valve piston in the closure state spring force. The spring can be further compressed or relieved. Such can be achieved for example by acting on the spring screw.

The predetermined working pressure is selected to be higher in terms of an embodiment of the handset as a punching or punching device usually as it corresponds to the pressure required to carry out the punching or punching process. In this respect, the predetermined working pressure can also be set so high that the return valve works without further measures only in the sense of a pressure relief valve. The same applies in principle for example for a training of the handset as a riveting tool. Alternatively, however, the training of the handset, in particular in the examples given variants, be provided so that when the return valve due to the predetermined working pressure, the moving part, as far as no further intervention takes place, runs back to its predetermined starting position. According to the innovation described here, however, a hydraulic pressure at which the return valve is moved to the open position, be achieved in that with one of a working operation, which is performed with the handset, independent action means an increase in pressure in the return valve acting hydraulic fluid volume is made. This pressure increase is carried out in the hydraulic fluid volume, which acts on the partial piston area of the return valve when the return valve is closed. The pressure may possibly be given for a short time. The pressure increase is chosen so that thereby the return valve is displaced into the open position. The prevailing with regard to the moving part for performing the operation in the force acting on the moving part hydraulic fluid pressure has not regularly reached the predetermined working pressure. It is thus given that the return valve can be opened hydraulically, before applied to the moving part of the release pressure to the return valve according to predetermined working pressure.

The return valve is independent of a given actually set maximum working pressure on the moving part hydraulically displaced in the open position. The return valve preferably closes only after a certain, acting on the return valve hydraulic pressure has dropped so far that the required due to the structural design of the return valve pressure load to hold the return valve in the open position is no longer given. The return valve can automatically with a changeable, ie preselected and compared to the predetermined working pressure modified Ar Beitsdruck be opened, preferably according to appropriate pressurization of the return valve.

Also, the working pressure, which - in one operation - only - is achieved, thereby be adjusted as a modified working pressure. Thus, for example, via a thumbwheel or buttons on the device by the user a working pressure can be specified as a modified working pressure, which is smaller than the maximum allowable working pressure, ie the above-mentioned predetermined working pressure at which the return valve preferably also opens automatically, or also corresponds to this maximum working pressure. The latter may be useful, for example, if the said maximum working pressure is to be actually achieved, but also only with greater accuracy. Thus, at an exemplary predetermined or maximum working pressure of 600 bar optionally working pressures of 50 to 600 bar can be adjusted continuously or stepwise. It is thus possible to adapt to the adaptation of the workpieces to be carried out by means of the device, while maintaining an automatic return of the moving part into the end position after reaching the optionally set working pressure.

It can also be provided that the adjustment of the modified working pressure can be performed from outside the handset, for example via a radio interface or optical interface.

The pressure increase acts temporally preferred only briefly. In terms of time, the pressure increase in the range of a few milliseconds can only be effective, for example. Over a period of 2 to 5 ms. The pressure increase is made in particular by feeding hydraulic fluid in the given with respect to a direction of flow of the hydraulic fluid in front of the valve seat line section. This line section is delimited before an opening of the return valve on the one hand by the Teilkol- benfläche the return valve and on the other hand by the piston surface of the moving part.

Due to the additional pressure load in the return direction of the hydraulic fluid in front of the valve seat, an initial pressure increase to displace the return valve into the open position essentially acts solely on the partial piston surface of the return valve. Essentially, it also acts decoupled from the moving part because, at the moment of increasing the pressure, it is only exposed to the hydraulic pressure "before" one of the pressure increase introducing means (considered in view of the flow direction of the hydraulic fluid through the open return valve) ,

The initial pressure increase to a trigger pressure of the return valve, for example. 600 bar, preferably moves a piston of the return valve from the valve seat, which, as known from the prior art, a return opening for the hydraulic fluid is released and the returning hydraulic fluid opposite the valve seat surface, ie the sub piston surface, acted upon enlarged piston area of the return valve and so keeps the return valve in the open position even with reduced pressure or decreasing pressure. The increase in pressure to achieve the triggering pressure is therefore carried out preferably only over a (with initially addressed) time-limited area, which requires only such a period of time that the piston of the return valve is lifted from the sealing position. The pressure increase can be carried out by blocking or throttling (eg. Cross-section reduction) of the line section in a region in the return flow of the hydraulic fluid before the return valve. For example. this can be a displaceable closure part acting in the manner of a slide or a valve tip.

It is preferably provided a blocking means which is releasably displaceable, for throttling or blocking the line section. The shut-off means may be a magnetically actuated, in particular electromagnetically operable closure means, which is preferably spring-loaded in the direction of a passage position.

In the resulting between the shut-off and the return valve portion of the line section, hereinafter referred to as the second section, hydraulic fluid is introduced to increase the pressure, preferably pumped. The introduced hydraulic fluid causes the desired linear displacement of the moving part when the shut-off device is open. In the shut-off position, on the other hand, the hydraulic fluid volume acting on the moving part is preferably separated from the second line section which is further supplied with hydraulic fluid. The resulting increase in pressure thus preferably acts exclusively on the partial piston surface of the return valve.

In a preferred solenoid valve as a shut-off means, the course of forces in the course of the closing operation is preferably selected so that the end, ie shortly before closing, the highest force is reached. In order to achieve an initial pressure increase, a sudden shut-off or throttling of the line section is made. This can be done manually by the user, for example via a correspondingly provided lever arrangement. In this regard, an electromagnetic displacement of a valve, for example a linearly displaceable solenoid valve, is preferred.

The return of the moving part in the end position can be stopped in a possible embodiment, in particular willpowered. The device can be put back into a ready-for-use position faster.

With the stopping of the return flow, the pressurization via the hydraulic medium to the return valve also drops until below the pressure value holding the return valve in the open position. The return valve automatically falls into the closed position.

By a blocking or at least throttling action, for example. A shut-off in the above line section of the return of the moving part can be stopped and in the region of the line section between the shut-off and the return valve (second line section) a pressure reduction can be achieved, which pressure reduction to a shift of Return valve leads to the closed position.

If at a pressure of, for example, 300 bar, the shut-off is triggered, the pressure in the (first) line section between shut-off and moving part remains, here, for example, 300 bar. In contrast, between the shut-off means and the return valve, the pressure in the second line section rises almost abruptly, except for the triggering pressure for the return valve of, for example, 600 bar. This conditional on further feeding (pumping) of Hydraulic fluid in this line section. Thereafter, the pressure in the second line section drops again.

In the region of the second line section, a pressure sensor can be provided which can detect when the pressure drop in the second line section is large enough for the blocking means to open again. It may alternatively or additionally be arranged in the first line section or directly associated with the hydraulic chamber, a pressure sensor. The pressure sensor arranged in the second line section is correspondingly decoupled from the pressure prevailing in the hydraulic chamber when the shut-off device is actuated, and only measures the pressure in the second line section which rises at short notice and very strongly as a rule. If, as preferred and explained below, the termination of the shut-off state occurs automatically, a pressure sensor in the second line section is also dispensable. With the pressure sensor in the first line section can then be followed continuously, the pressure curve in the hydraulic chamber.

It can also be provided that a return of the moving part is triggered in response to a measured by a pressure sensor pressure value by subsequent successful automatic opening of the return valve and that the working pressure, as previously mentioned, in which the opening of the return valve is triggered, is adjustable.

Due to the adjustability of the hydraulic or working pressure with which is acted upon by the moving part on a workpiece or the like, a particular in particular by the user in the simplest manner can be brought about adaptation, for example, to the workpiece conditions. For example, softer, correspondingly easier deformable materials are subjected to lower working or hydraulic pressure than, on the other hand, harder materials. Workpieces with different parameters can thus be processed with just one hand-held device. With the adjustable working pressure, a working pressure can be selected which is different from the pressure in the hydraulic fluid, in which the return valve would be spent due to its structural design anyway in its open position. Reference is also made to the above statements. This pressure, in which the return valve is spent due to its structural design in the open position, is referred to as the predetermined working pressure. However, the selected, set working pressure can also, as already stated above, be chosen to coincide with said predetermined working pressure. Regardless of the selected working pressure, the specified working pressure remains unchanged. It only plays no role as long as a selected working pressure below the specified working pressure or in accordance with this is provided.

There may be provided an adjustment for different, selectable working pressures. This can be a setting wheel or a control slide, alternatively an arrangement of a plurality of keys, each key being assigned a predetermined working pressure. Also, a keyboard may be provided with an associated display. A setting of the selectable working pressure may optionally be alternatively or additionally also via a non-mechanical interface, in particular a radio and / or optical interface to the device vornehmbar. Also, with regard to the display, a display may be provided which reflects the actual selected working pressure.

[0040] In addition, as is also preferred, provision can be made for a return of the moving part to be initiated at the same time as the actuation of the hand-operable switch of the hand-held device is lifted. The hand-operated

Switch is that switch that is to be operated by a user, in particular to press, to start a work operation of the device and (continue) to perform.

If, as is preferred, the return of the moving part is triggered when the loading is canceled, it can also be provided that a termination of the return of the moving part is achieved by repeated actuation. This can be achieved in particular by the fact that when again actuated (again) a shut-off or throttling of the line section takes place, for example (again) an electrical voltage is applied to the solenoid valve to shut off the line section. The pressure drop introduced in the second line section between the shut-off area and the return valve causes the return valve to close.

By canceling the Schalterbeaufschlagung, in particular releasing the switch usually designed as a switch, so preferably not only a termination of the advancement of the moving member is achieved, but rather a return of the same in the direction of a basic position.

The return can be achieved in that the return valve, which opens even when reaching a predetermined working pressure is moved with one of the measures already described in an open position, resulting in a return of the hydraulic fluid acting on the moving part.

On the other hand, the return valve can also be opened mechanically, for example electromechanically, for example as a function of the detection of a cancellation of the switch application. This is directly, for example via a linkage, in the formation of the return valve as a valve piston, for example via a related piston rod, acted on the return valve.

The switch application can be sensed. Also, for example, the motor current of a drive driving the hydraulic pump can be monitored. This in particular in the case that the operation of the hydraulic pump is directly dependent on the switch application. A discontinuation of the relevant motor current is considered as a waiver of the switch application. A signal for opening the return valve can be generated.

The opening of the return valve can also, as further preferred, be achieved by increasing the hydraulic pressure acting on the return valve. In this regard, reference is made to the above-described embodiments. It can also be provided, for example, that the return of the moving part only by a corresponding switch operation, ie in particular a repeal of the application of the manually operated switch, if previously the device side, a first workpiece contact has been found. For this purpose, a corresponding contact or proximity sensor can be provided. Also, for this purpose, the motor current of the pump drive can be monitored. Alternatively or additionally, the signal of a pressure sensor in the hydraulic fluid detecting pressure sensor can be evaluated for this purpose. If in the course of carrying out, for example, a pressing, cutting or punching process for certain reasons, such as in an emergency, a return is desired, the sole release of the actuation switch is sufficient. The movement section is not only quiet, but at the same time moves back. Also, the return valve, for example, via a piston rod directly connected to a valve piston, as indicated, or a similar linkage, on which piston rod or linkage acts a servo motor, be moved to trigger the return movement of the moving member in the open position. Further, it can be provided that a complete return of the moving part is first waited before a next operation is released. For example, a predetermined fixed period of 5 or 10 seconds can be specified. Alternatively, it can also be determined via the pressure sensor whether the return has taken place (completely). A possible (additional) hydraulic pressurization of the

Return valve for triggering a movement of the moving part back to the end position allows an energy-efficient work. Since the device as a whole does not necessarily have to work until the triggering pressure of the return valve is reached, but the return flow can then be initiated in a targeted manner when the intended processing has taken place, in the case of an accumulator operated handheld device with a charged accumulator significantly more edits are made than in solutions in which always the fixed release pressure must be achieved at each operation.

In the known solutions, the switch-off can not always take place at the desired pressure despite a pressure sensor being provided. If, for example, a pressure of 230 bar is desired, a pressure of, for example, 300 bar may still develop with appropriate inertia. A shutdown at a certain pressure, such as the mentioned 230 bar is essential in particular in connection with punch rivets, since depending on the material, an overpressing of the rivet can otherwise occur. By acting on the return valve short-term pressure increase is given a rapid pressure drop on the moving part by opening the return valve. The reaction, i. the opening of the return valve, takes place in a time range of one or a few milliseconds. It can also be a time range of a few milliseconds, for example two, four or five milliseconds.

Brief description of the drawings

The invention is explained below with reference to the accompanying drawing, which illustrates only one embodiment. 1 shows an overall view of a hydraulically operated hand-held device in the form of a pressing device, relating to a first embodiment; a plan view of the handset; Fig. 3 is a representation corresponding to Figure 1, but partially broken away;

FIG. 4 shows the enlargement of region IV in FIG. 3; FIG.

Fig. 5 is a representation corresponding to Figure 4, upon reaching a

Pressure threshold in the course of a movement of a moving part of the handset in a working position;

Fig. 6 is a representation corresponding to Figure 4, with an open shut-off valve and open return valve;

7 shows a sequence illustration of FIG. 6 after stopping a return movement of the moving part in an initial position by closing the closing means;

Fig. 8 is a representation corresponding to Figure 2, relating to a second embodiment;

9 shows an illustration of the second embodiment corresponding to FIG. 4;

10 shows the second embodiment in a representation according to FIG

5;

FIG. 11 shows a sequence illustration of FIG. 10 according to FIG. 6. Description of the embodiments

Is shown and described, first with reference to Figure 1, a hydraulically operated handset 1 in the form of a pressing device with an electric motor 2, a hydraulic pump, not shown in detail, a hydraulic fluid reservoir 3 and designed as a hydraulic piston movement part. 4

The moving part 4 is movable relative to a fixed part 5 formed by the device housing or, for example, the cylinder in which the hydraulic piston moves. The movement part 4 is now, for example, the tool holder shown in Figure 1. It may also be the hydraulic piston, for example (see FIG. 3).

In particular, the components hydraulic fluid reservoir 3, return valve 8, shut-off means 19, one part device 27 and optionally also further are housed in a device body K not shown in more detail here. The hydraulic chamber 6 includes the space in which hydraulic fluid is pumped. This starts at the pressure side of the hydraulic pump. As shown, for example, in FIG. 3, the hydraulic chamber 6 has a return line 7, via which the hydraulic medium can flow back into the hydraulic medium reservoir 3 via a return valve 8. As can be seen in particular from Figures 4 and 7, the hydraulic chamber 6 changes with the working state of the handset 1. In the illustration of Figure 4, the moving part 4 in a relation to Figure 3 changed position. After opening the return valve 8 (Figure 6), the hydraulic piston or the moving member 4 moves back in the direction its rest position according to FIG. 3. The space upstream of the hydraulic piston in this respect is included in the hydraulic chamber 6, but at the same time also with the return valve open, the passage through the valve seat and the space immediately before the return valve 8. [0061] The electric motor 2 for operating the hydraulic pump and Thus, to move the moving part 4 in the direction of the working position is activated by a preferably designed as a hand-operated button switch 9. The electrical supply of the electric motor 2, as moreover preferably also a switching / control electronics, via an unrepresented, device-side accumulator or via an electrical line.

The return valve 8 is pressed in the valve closure position by means of a pressure spring 10 in the valve seat. In detail, the valve seat preferably consists of a screw-in part 12, which is screwed into the housing of the hand-held device 1 via a thread 11. In the valve seat, optionally in the screw 12, is a

Flow hole 13 is provided. This is fluidly connected to the return line. 7

Due to the narrow cross section of the flow bore 13 in the valve seat in cooperation with the bias applied by the pressure spring 10, the return valve 8 opens only when a certain triggering pressure is exceeded. It is the specified working pressure mentioned above. This release pressure can be, for example, 600 or 700 bar. After the return valve 8 has opened, the pressure of the hydraulic fluid is no longer limited to the area corresponding to the cross-sectional area of the flow bore 13, a partial piston area, for example given by a valve needle 14, but to the entire hydraulic cavity Therefore, the open return valve 8 is held by a very low pressure in the return line 7, for example, a pressure of 2 to 5 bar, already in the open position. The valve needle 14 does not have to be ideally tapered. In any case, it is preferably cone-shaped.

This pressure is preferably generated during the return of the moving part 4 by acting on the moving part 4 and the moving part 4 in the end position stressing spring 16.

In downstream flow direction after the flow bore 13, the pressure is again significantly lower. For example, the pressure, in particular at the beginning of the return of the moving part is only 3/4 or less of the pressure before the flow bore 13 or the valve seat, in practice, for example, about half. However, this pressure difference is substantially equalized thereafter and, as a rule, is only comparatively small soon after the start of the return of the moving part.

After opening the return valve 8 of the adjoining the flow hole 13 space 26 is included to the lower surface 17 of the return valve piston 15 in the hydraulic chamber. The hydraulic medium then flows via a drain opening 18 into the storage space 3. The space 26 is referred to above and below as a valve chamber. Without further action, in particular without external intervention, for example by the user, the hydraulic or release pressure lifting the valve needle 14 from the valve seat corresponds to the specified working pressure at the movement part 4. However, one possibility is created to shift the return valve 8 in its opening position, without the hydraulic pressure applied to lift the return valve 8 is applied to the moving part 4. Correspondingly, work, for example pressing with the hand-held device 1 is possible, which requires lower working pressures on the movement part 4 than the triggering pressure for the return valve 8.

For this purpose, a shut-off means 19 is assigned to the upstream in the outflow direction upstream of the return valve 8 hydraulic chamber. This shut-off means 19 may, as also preferred, be designed as an electrically actuated solenoid valve. The shut-off means 19 is composed in the illustrated embodiment essentially of a linearly displaceable shut-off piston 20 with a conical locking surface and an electrically controllable solenoid 21.

The shut-off means 19, in particular the shut-off piston 20 is arranged einragend in the return line 7. The shut-off piston 20 is adapted to subdivide the return line 7 at a given blocking of the same in a viewed in the return direction of the hydraulic medium first line section 22 between the moving part 4 and the shut-off means 19 and a second line section between the shut-off means 19 and the return valve 8. In a further preferred embodiment, the shut-off piston 20 is loaded out of its valve seat position, in which a separation of the first and second line sections, in an open position. For this purpose, as also shown, a return spring 24, in particular in the form of a compression spring, can be provided for the corresponding pretensioning.

The supply of hydraulic fluid for advancement of the moving part 4 in the direction of the working position takes place with the shut-off means 19 open in the region of the second line section 23. Here, a check valve 25 is provided. The handset 1 preferably has a one-part device 27, by means of which the working part of the maximum pressure applied to the movement part 4 can be preset by the user. In the illustrated embodiment, a plurality of keys 28 are provided for this purpose, to which keys 28 predetermined pressure values are stored. With the adjusting device can be adjusted according to the above-described selected, compared to the predetermined working pressure modified (or in some cases also hereby matching) working pressure. On the other, possibly alternative possibilities of the aforementioned radio link, etc., reference is also made at this point. For example, a leading to the triggering of the return valve working pressure of 200 bar or 300 bar can be preselected.

An evaluation / control electronics evaluates in the course of the movement of the moving part 4 in the direction of the working position pressure measurement values of a pressure sensor 29, 29 'and compares them with the set via a key 28 pressure setpoint. The pressure sensor 29 'can be seen a pressure be sensor, which is assigned directly to the hydraulic chamber 6. It may also be a pressure sensor 29 alternatively or additionally in the return line 7, possibly also, as shown in Figure 4, may be arranged in the second line section 23. Since, however, as described below in more detail, the shut-off piston 20 preferably automatically moves back into the open position and this is not necessary a pressure measurement is required, but on the other hand but in befindlicher in the closed position shut-off piston 20, the pressure sensor 29 is no longer the pressure of the hydraulic chamber 6, it is preferred that the pressure sensor 29 'assigned directly to the hydraulic chamber 6 is provided in any case, and more preferably only this pressure sensor 29' is provided.

Upon reaching the pressure setpoint, a corresponding signal is generated, which leads to an activation of the actuating magnet 21 of the blocking means 19. The shut-off piston 20 moves according to the activation of the actuating magnet 21 against the force of the preferably provided return spring 24 abruptly in the feed position shown in Figure 5. As a result, the preferred conical sealing surface of the shut-off piston 20 sealingly against the facing opening edge of the first line section 22nd The hydraulic medium further pumped out of the storage space 3 into the second line section 23 results in a corresponding increase in pressure above the pressure setpoint prevailing in the first line section 22. As a result of the very small receiving volume for hydraulic fluid resulting essentially solely from the second conduit section 23, in particular within a fraction of a second, for example. within 2 to 5 ms, the trigger pressure for displacement of the return valve 8 in the open position reached (see Figures 5 and 6).

After pressure-related displacement of the return valve piston 15 in the open position, the solenoid 21 of the blocking means 19 drops. The shut-off piston 20 is displaced in particular spring-loaded into the open position and thus lifted from the valve seat, so that the return of the hydraulic fluid from the hydraulic chamber 6 can be carried back into the hydraulic fluid reservoir 3, in which case the return valve 8 held in the raised position so long is until the moving member 4 reaches the end position shown in Figure 3 and / or the opening holding pressure for the return valve 8 falls below.

The displacement of the shut-off piston 20 in the open position can be set differently. Preferably, the solenoid 21 is designed with such a small force on the shut-off piston 20, that the pressure difference between the hydraulic chamber 6 and the second line section 23 generated by the shut-off piston 20 after the return valve 8 has opened, regardless of whether the shut-off piston 20 is still through the actuating magnet 21 is acted upon, is pressed into the open position. For example, this can already be set at a pressure difference of 1 bar or more. This displacement into the open position is also desirable and necessary, since if the closure is too long, the pressure in the second line section 23 could drop below the pressure at which the return valve 8 closes. Furthermore, it can be provided that the application of the actuating magnet 21 is time-controlled. Thus, if a closure of the shut-off, specifically here the shut-off piston 20, is triggered, it can be provided that the required for this purpose actuation of the solenoid 21 for a predetermined period, preferably also in the range of milliseconds to tenths of a second is given. If, how next preferred and already mentioned, the said force acting on the shut-off piston 20, is set correspondingly low, regardless of still given loading of the actuating magnet of the shut-off piston by said pressure difference also already moved back into an open position. The opening force, which acts on the shut-off piston, of course, also depends on the area which shuts off the shut-off piston at the transition from the first to the second line section 22 and 23 respectively. This is also chosen so that preferably automatically, regardless of an action on the actuating magnet, adjusts said opening. The pressure increase at the return valve 8 by shutting off the return line 7 by means of the shut-off 19 may act initially. When the return valve 8 is raised and subsequent displacement of the shut-off means 19 into the valve open position, the pressure prevailing through the return of the moving member 4 acts on the return valve 8. The electric actuation of the shut-off means 19 can also initially be impulse-like, so that after complete advance stroke of the shut-off means Shut-off piston 20 this is almost suddenly in the forward position shown in FIG 5. In the case of a regular expiry of a working cycle, that is to say in particular if no premature termination of the return flow of the moving part is desired, the shut-off piston 20 remains in the raised position which releases the return line 7 or connects the line sections 22 and 23.

By a premature, prior to complete movement of the movement moving part electrical loading of the shut-off 20 a ne closing of the return line and thus a separation of the first and second line section 22, 23 can be achieved, resulting in such Pressure drop in the flow direction before the return valve 8, corresponding to the second line section 23, leads, so that in this way a desired closure of the return valve 8 is achieved.

The advancement of the moving part 4 into the working position is preferably maintained only as long as the user actuates the switch 9. In one embodiment, when the switch 9 is released (even before a work process has been completed), a signal is generated, which leads to activation of the shut-off means 19 and thus to a pressure increase in the second line section 23 in the return flow direction before the return valve 8. Accordingly, with the release of the switch 9, the return valve 8 is moved to the open position, resulting in an automatic return of the moving part 4 in the end position.

In order to achieve this result safely, although inertial forces alone acting on a pump part, such as a pump piston, may suffice, it is preferably provided that release of the switch does not lead exactly to a standstill of the pump at the same time, but also the pump or a motor acting on this delayed off. The delay is chosen so that the required pressure rise can be achieved, for example in the range of a few milliseconds to tenths of a second. The shut-off piston 20 may be arranged rectified to the

Return valve 8. The longitudinal axes of shut-off piston 20 and return valve 8 can be parallel to each other.

FIGS. 8 to 11 show a second embodiment of a hand-held device 1. In terms of functionality, this is essentially identical to the previously described first exemplary embodiment. Thus, the handset 1 also here via a trigger pressure controllable return valve 8, for connecting the return line 7 with the hydraulic fluid supply chamber. 3

In addition, an electromagnetically actuated blocking means 19 is also provided here for acting on the hydraulic fluid volume located in the return direction of the hydraulic fluid upstream of the return valve 8.

The function and operation of the shut-off means 19 is the same as the previously described embodiment. Also, the return valve 8 acts substantially equal to the above-described embodiment, in particular with regard to the triggering of the return valve 8 and the concomitant lifting the return valve piston 15 in a return line 7 to the drain opening 18 of the storage space 3 connecting position. The raised return valve position, in which the return valve piston 15 is displaced out of the valve seat to release the return path to the storage space 3, can be locked in this embodiment. For this purpose, the return valve piston 15 facing away from the valve needle 14 having the end of a waist-like circumferential constriction 26 have. This results in a rear grip region, in which in the raised return valve piston position according to FIGS. 10 and 11, a locking spring 30 which is spring-loaded in the blocking direction is inserted. The locking finger 30 acts in the illustrated embodiment transversely to the longitudinal extent and to the displacement direction of the return valve piston 15th The locking finger 30 is held linearly displaceable in a housing section 31. In this housing section 31, a compression spring 32 acts on the locking finger 30, concretely stressing the locking finger 30 in the direction of the return valve piston 15. Facing away from the cooperating with the return valve piston 15 end of the locking finger 30, an actuating portion 33 is integrally formed on this, over the housing portion 31 over which a pulling movement against the action of the compression spring 32 of the locking fingers 30 can be moved back, which the release the return valve piston 15 has the consequence. The latter falls due to the application of the pressure spring 10 back into the valve seat position, in which a shut-off of the return path is reached.

The relapse of the return valve piston 15 in the valve seat position is preferably only possible in this embodiment, when the force acting on the entire piston surface hydraulic pressure is lowered to a level that allows this displacement of the piston in the valve seat position. This can be achieved with complete return of the moving member 4 in a starting position or by activation of the shut-off 19 in the course of the return movement of the moving part 4, in the latter case, even if not completely run-back movement part 4 according to shut the return line 7 in the resulting hereinafter second line section 23 sets a pressure reduction, which allows the return displacement of the return valve piston 15 in the valve seat position.

[0099] The above explanations serve to explain the inventions as a whole covered by the application, which belong to the state of the art. At least through the following combinations of features, each self-training, namely:

A method which is characterized in that the hydraulic pressure acting on the return valve 8 for triggering a movement of the movement part 4 in the end position by a separately triggerable, leading to the opening of the return valve 8 pressure increase in a flow direction of the hydraulic means Procedure is increased in the end position before the return valve 8 located hydraulic fluid volume.

[0010] A method which is characterized in that the hydraulic pressure acting on the return valve 8 by a separately triggerable, leading to the closing of the return valve 8 pressure reduction in a hydraulic medium in the flow direction of the hydraulic medium in the process in the end position before the return valve 8 located is lowered.

A method which is characterized in that to achieve the reduction in pressure, a line section in the flow direction mentioned before the return valve 8 is shut off or throttled.

A method which is characterized in that to achieve an increase in pressure, a line section in the aforementioned flow direction is shut off or throttled in front of the return valve 8 and in the thus blocked off or throttled line section hydraulic fluid is introduced to increase the pressure.

A method, which is characterized in that the hydraulic fluid pump delivers into a second line section 23, which is also flowed through by the hydraulic fluid flowing when the return valve 8 is open. A method, characterized in that the second line section 23 is shut off to achieve the pressure increase.

[0010] A hand-held device, which is characterized in that the hydraulic pressure acting on the return valve 8 for triggering a movement of the movement part 4 into the end position by a separately triggerable, leading to the opening of the return valve 8 pressure increase in a flow direction of the hydraulic means Method in the end position before the return valve 8 located hydraulic fluid volume can be increased.

[00107] A hand-held device, which is characterized in that the hydraulic pressure acting on the return valve 8 is triggered by a separately releasable pressure reduction for closing the return valve 8 in a hydraulic medium volume located in the flow direction of the hydraulic fluid in the end position before the return valve 8 is lowerable.

A handset, which is characterized in that to achieve the pressure reduction, a line section in the aforementioned flow direction before the return valve 8 can be shut off or throttled.

A hand-held device, which is characterized in that to achieve an increase in pressure, a line section in the aforementioned flow direction before the return valve 8 can be shut off or throttled and in the thus blocked or throttled line section hydraulic means for increasing the pressure can be introduced.

[00110] A hand-held device, which is characterized in that the hydraulic fluid pump delivers into a second line section 23, which can also be flowed through by the hydraulic medium flowing when the return valve 8 is open. A handset, which is characterized in that the second line section 23 can be shut off to achieve the pressure increase.

[00112] A hand-held device, which is characterized in that the blocking means 19 is biased into an open position. A hand-held device, which is characterized in that the shut-off means 19 consists of a magnetically actuable closure means.

All disclosed features are essential to the invention (individually, but also in combination with one another). The disclosure of the associated / attached priority documents (copy of the prior application) is hereby also incorporated in full in the disclosure of the application, also for the purpose of including features of these documents in claims of the present application. The subclaims characterize with their features independent inventive developments of the prior art, in particular in order to undertake divisional applications based on these claims.

List of reference numbers

1 handset 28 button

2 electric motor 29 pressure sensor

3 Hydraulic fluid reservoir 29 'Pressure sensor

4 moving part 30 locking fingers

5 fixed part 31 housing section

6 hydraulic chamber 32 compression spring

7 return line 33 operating section

8 return valve

9 switches

10 pressure spring

11 threads

12 screwed part

13 flow bore

14 valve needle

15 return valve piston

16 spring

17 lower surface

18 drain opening

19 Shut-off device K Device body

20 shut-off piston

21 solenoid

22 first line section

23 second line section

24 return spring

25 check valve

26 constriction

27 setting device

Claims

claims

1. A method for operating a hydraulically operated hand tool (1), eg. A pressing device and / or a punching or punching device, wherein the handset (1) comprises a hydraulic pump, a moving part (4), a fixed part (5) and a return valve ( 8) with an associated valve seat, wherein furthermore the movement part (4) is moved into a working position by building up a hydraulic pressure, which results from filling a hydraulic space (6) with hydraulic fluid from a storage space (3) using the hydraulic pump , wherein it is achievable that the movement part (4) is automatically moved from the working position to an end position upon reaching a predetermined working pressure by opening the return valve (8), characterized in that the valve acting on the return valve (8) Hydraulic pressure for triggering a movement of the moving part (4) in the end position by a separately triggerable, for opening the Rücklaufven tils (8) is increased in a hydraulic fluid in the flow direction of the hydraulic medium in the process in the end position in front of the valve seat of the return valve (8) located increasing hydraulic fluid.

2. Method according to the features of the preamble of claim 1 or claim 1, characterized in that the force acting on the Rücklaufven- valve (8) hydraulic pressure by a separately triggered, for

Closing the return valve (8) leading pressure reduction is lowered in a direction of flow of the hydraulic fluid in the process in the end position in front of the valve seat of the return valve (8) located hydraulic fluid volume. 3. The method according to any one of the preceding claims, characterized in that to achieve the pressure reduction, a line section is shut off or throttled in the direction of flow before the return valve (8).

Method according to one of the preceding claims, characterized in that to achieve an increase in pressure, a line section in said flow direction in front of the return valve (8) is shut off or throttled and in the thus blocked or throttled line section hydraulic means for increasing the pressure is introduced.

Method according to one of the preceding claims, characterized in that the hydraulic fluid pump in a second line section (23) supplies, which is also flowed through by the open when the return valve (8) hydraulic fluid.

6. The method according to any one of the preceding claims, characterized in that the second line section (23) is shut off to achieve the pressure increase.

Hydraulically operated hand tool (1), eg. Pressing device or punching or punching device, wherein the handset (1) comprises a hydraulic pump, a moving part (4), a fixed part (5) and a return valve (8) with an associated valve seat, wherein further the moving part (4) by building a hydraulic pressure, which results by filling a hydraulic chamber (6) with hydraulic fluid from a storage space (3) using the hydraulic pump is movable in a working position, wherein it is achievable that the moving part (4) upon reaching a predetermined working pressure by opening the return valve (8) is to be moved automatically from the working position to an end position, characterized in that on the return valve (8) acting Hydraulic pressure for triggering a movement of the moving part (4) in the end position by a separately triggerable to the opening of the return valve (8) leading pressure increase can be increased in a flow direction of the hydraulic fluid in the process in the end position in front of the valve seat of the return valve (8) located hydraulic fluid volume ,

Hand device according to the features of the preamble of claim 7 or claim 7, characterized in that on the return valve (8) acting hydraulic pressure by a separately triggerable, closing the return valve (8) leading pressure reduction in a flow direction of the hydraulic fluid in the method in the end position in front of the valve seat of the return valve (8) located hydraulic fluid volume can be lowered.

Hand tool according to one of claims 7 or 8, characterized that in order to achieve the pressure reduction, a line section in the aforementioned flow direction before the return valve (8) can be shut off or throttled.

10. Hand tool according to one of claims 7 to 9, characterized in that to achieve an increase in pressure, a line section in said flow direction before the return valve (8) can be shut off or throttled and in the thus blocked or throttled line section hydraulic means for increasing the pressure can be introduced.

Hand tool according to one of claims 7 to 10, characterized in that the hydraulic fluid pump in a second line section (23) supplies, which can also be flowed through by the hydraulic fluid flowing when the return valve (8) is open.

12. Hand tool according to one of claims 7 to 11, characterized in that the second line section (23) to achieve the pressure increase can be shut off.

13. Hand tool according to one of claims 7 to 12, characterized in that the blocking means (19) is biased in an open position.

14. Hand tool according to one of claims 7 to 13, characterized in that the blocking means (19) consists of a magnetically actuable closure means.

15. A method or handset, characterized by one or more of the characterizing features of one of the preceding claims.