Device with hydraulic cylinder and method for impact absorption of a working piston movable in the hydraulic cylinder

Abstract

This disclosure primarily relates to a hydraulic cylinder (6) having a hydraulically loaded working piston (10) movable therein for transmitting working force to an object to be processed outside the hydraulic cylinder (6) in the event of a reaction force. The working piston (10) has a loading surface (12) defining a loading space between the working piston (10) and the hydraulic cylinder (6) along the working direction (R) for transmitting the working force. For the purpose of performing the work process, hydraulic fluid acts on the loading surface (12) to move the working piston (10) in the working direction (R) while expanding the loading space. This disclosure also relates to a hydraulic working tool (1) having a working head (17) and a hydraulically loaded working piston (10) movable within the hydraulic cylinder (6). This disclosure further relates to a method for absorbing impact from the hydraulically loaded working piston (10) movable within the hydraulic cylinder (6). To achieve effective shock absorption, this disclosure proposes that the working piston (10) be mechanically held when the reaction force is dissipated, to prevent the working piston (10) from continuing to move in the working direction (R) when the reaction force has not been dissipated. It is important in the case of the hydraulic working tool (1) that it has such a hydraulic cylinder (6). The primary and fundamental basis of the method for shock absorption is to prevent the working piston (10) from continuing to move in the working direction (R) when there is no reaction force dissipation by mechanically holding the working piston (10) when the reaction force is suddenly dissipated.

Description

Technical Field

[0001] This disclosure primarily relates to an apparatus having a hydraulic cylinder and a hydraulically loadable working piston, wherein the working piston is movable within the hydraulic cylinder and configured to transmit a working force to an object to be processed outside the hydraulic cylinder in the event of a reaction force. Furthermore, the working piston has a loading surface that defines a loading space between the working piston and the hydraulic cylinder along the working direction in which the working force is transmitted. The apparatus also includes a hydraulic fluid disposed within the hydraulic cylinder, wherein the hydraulic fluid enters the loading space, causing the loading space to increase and acting on the working piston to move the working piston toward the loading surface along the working direction.

[0002] This disclosure also relates to a method for absorbing the impact of a hydraulically loaded working piston that can move within a hydraulic cylinder, the working piston being used to transmit working force to an object to be processed outside the hydraulic cylinder in the presence of a reaction force, wherein the working piston has a loading surface that defines a loading space between the working piston and the hydraulic cylinder in the working direction in which the working force is transmitted, and the hydraulic fluid can be introduced onto the loading surface to expand the loading space in order to move the working piston in the working direction. Background Technology

[0003] Hydraulic cylinders with a hydraulically loaded working piston that can move therein are known in various respects. For example, reference should be made to WO 2003 / 084719 A2 (US 7 412 868 B2).

[0004] A hydraulic cylinder is known from document US 2,863,346 A, in which two hydraulic pistons are arranged one behind the other. The two hydraulic pistons are working pistons that transmit working force to an object outside the hydraulic cylinder. The second working piston, in the working direction, is initially moved by the first working piston through direct contact at the start of the working process. If the first working piston reaches its limit of mobility, for example, due to the end of its action on the object and thus causing a further increase in the pressure in the hydraulic fluid, a pressure-dependent valve in the first working piston opens. The hydraulic fluid flowing through the first working piston then moves the second working piston while filling the chamber between the first and second working pistons, so that the second working piston can also act on an object outside the hydraulic cylinder. When the reaction force suddenly decreases, the second working piston can transfer the impact energy to the hydraulic cylinder via a return spring compressed in this force transmission.

[0005] A hydraulic cylinder having a hydraulically loaded working piston movable therein is known from document WO 2018 / 065513 A1 (US 2019 / 0240826 A1), as well as a hydraulic working tool having a working head and a hydraulic cylinder. A method for absorbing impact on the hydraulically loaded working piston movable within the hydraulic cylinder is also known. To achieve the desired impact absorption, it is suggested, for example, that the transmission device be decoupled from the electric motor used to ultimately drive the pump to deliver the hydraulic fluid, i.e., that a stop-limiting mobility is established between the transmission device and the electric motor.

[0006] A hydraulic cylinder or working tool and a method for shock absorption are known from document WO 2017 / 080877 A1 (US 10 821 593 B2), wherein a hydraulic chamber filled with hydraulic fluid is formed behind the working piston in the working direction, and the hydraulic chamber decreases as the working piston moves in the working direction when the hydraulic fluid is forced from the hydraulic chamber into a loading space. In the event of a sudden loss of reaction force, the resulting sudden movement of the drive piston in the working direction is damped by the filled hydraulic chamber.

[0007] A device is known from document US3 267 573 A, in which the working piston continues to move unimpeded as the reaction force decreases until it stops at an element that absorbs the impact. Furthermore, a device is known from document CH 370 617 A, in which the working piston is moved to a cutting position with the aid of combustion gases released during an explosion. The working piston continues to travel unimpeded, performing the thus applied motion, until it reaches a stop position. Summary of the Invention

[0008] Starting with the prior art, such as WO 2017 / 080877 A1, the technical problem addressed by this disclosure is to construct such a device advantageously in terms of shock absorption and to provide a method for shock absorption (or damping) that is advantageous in terms of shock absorption.

[0009] The aforementioned technical problem is primarily solved by a device comprising a hydraulic cylinder and a hydraulically loaded working piston. The working piston is movable within the hydraulic cylinder and configured to transmit a working force to the object to be processed outside the hydraulic cylinder upon the application of a reaction force. The working piston also has a loading surface that defines the boundary of a loading space formed between the working piston and the hydraulic cylinder along the working direction in which the working force is transmitted. The device further comprises hydraulic fluid disposed within the hydraulic cylinder. The hydraulic fluid enters the loading space, causing the loading space to increase and acting on the working piston to move it along the working direction toward the loading surface. The working piston is configured to, upon the dissipation of the reaction force... Before reaching the stop position, the piston is mechanically held in the working direction by the mechanical coupling between the working piston and the support, thereby preventing additional movement of the working piston in the working direction, which would occur without a reaction force. The support is an intermediate piston arranged in front of the working piston in the working direction and having a coupling protrusion for engaging with the coupling stop of the working piston. Alternatively, the support can be formed by a hydraulic cylinder, wherein the working piston and the hydraulic cylinder are mechanically coupled by a spindle assembly, wherein the spindle assembly is fixedly connected inside the hydraulic cylinder, and a spindle nut rotatably accommodated in the working piston engages with the spindle assembly. The working piston and the hydraulic cylinder are mechanically coupled by the spindle assembly and the spindle nut. The underlying principle is that the working piston is constructed to be mechanically held in the working direction by mechanical coupling between the working piston and the support before reaching the stop position when the reaction force is dissipated, thereby preventing additional movement of the working piston in the working direction, which would (originally) occur without the reaction force being dissipated. The support is an intermediate piston arranged in front of the working piston in the working direction and having a coupling protrusion for engaging with the coupling stop of the working piston. Alternatively, the support can be formed by a hydraulic cylinder, wherein the working piston and the hydraulic cylinder are mechanically coupled by a spindle assembly (or mandrel assembly).

[0010] The aforementioned technical problem is also solved in terms of the device by a device having a hydraulic cylinder and a hydraulically loaded working piston, wherein the working piston is movable within the hydraulic cylinder and configured to transmit the working force to the object to be processed outside the hydraulic cylinder when a reaction force is generated, wherein the working piston has a loading surface that defines the boundary of the loading space formed between the working piston and the hydraulic cylinder along the working direction of transmitting the working force, the device also having a hydraulic fluid disposed in the hydraulic cylinder, wherein the hydraulic fluid enters the loading space, causing the loading space to increase and act on the working piston to move the working piston in the working direction toward the loading surface, the working piston being configured to be mechanically held in the working direction by a mechanical coupling between the working piston and a support before reaching a stop position when the reaction force is dissipated, thereby preventing additional movement of the working piston in the working direction that would occur when no reaction force is dissipated, wherein the support is an intermediate piston or formed by the hydraulic cylinder and has a coupling protrusion constructed on the support, and the working piston has a coupling stop. The underlying principle is that the working piston is constructed to be mechanically held in the working direction by mechanical coupling between the working piston and the support before reaching the stop position when the reaction force is dissipated, thereby preventing additional movement of the working piston in the working direction that would occur without the reaction force being dissipated. The support is an intermediate piston or is formed by a hydraulic cylinder and has a coupling protrusion constructed on the support, and the working piston has a coupling stop.

[0011] Regarding the method for shock absorption, the aforementioned technical problem is solved by a method for shock absorption using a hydraulically loaded working piston that can move within a hydraulic cylinder. The working piston is used to transmit working force to the object to be processed outside the hydraulic cylinder when a reaction force is generated. The working piston has a loading surface that defines a loading space between the working piston and the hydraulic cylinder in the working direction in which the working force is transmitted. The hydraulic fluid, in order to move the working piston in the working direction, can introduce the loading space onto the loading surface while expanding the loading space. When the reaction force suddenly dissipates, before reaching a stop position, the working piston is mechanically held in the working direction to prevent further movement in the working direction that would be possible without the dissipation of the reaction force. This obstruction is achieved through mechanical coupling between the working piston and a support. In this configuration, an intermediate piston is positioned as a support and is located in front of the working piston in the working direction. The loading space is divided into a front space and a working space by the intermediate piston. The front space is located between the bottom of the cylinder and the intermediate piston, while the working space is located between the working piston and the intermediate piston. Hydraulic fluid is introduced into the working space from the front space when the working space expands. When the reaction force is suddenly dissipated, the mechanical coupling between the working piston and the intermediate piston prevents the pistons from moving away from each other. Alternatively, the hydraulic cylinder can be configured as a support, and the mechanical coupling between the working piston and the hydraulic cylinder can be achieved through a spindle assembly. The spindle assembly is fixedly connected inside the hydraulic cylinder, and a spindle nut rotatably accommodated in the working piston engages with the spindle assembly. The working piston and the hydraulic cylinder are mechanically coupled through the spindle assembly and the spindle nut. The underlying principle is that, upon sudden dissipation of the reaction force, before reaching the stop position, the working piston is mechanically held in the working direction to prevent further movement of the working piston in the working direction that would be possible without the reaction force dissipating. This obstruction is achieved through mechanical coupling between the working piston and the support. An intermediate piston is configured as a support and is arranged in front of the working piston in the working direction. The loading space is divided into a front space and a working space by the intermediate piston. The front space is between the cylinder bottom and the intermediate piston, and the working space is between the working piston and the intermediate piston. Hydraulic fluid is introduced into the working space from the front space as the working space expands. Upon sudden dissipation of the reaction force, the mechanical coupling between the working piston and the intermediate piston prevents the pistons from moving away from each other. Alternatively, the hydraulic cylinder can be configured as a support, and the mechanical coupling between the working piston and the hydraulic cylinder can be achieved through a spindle assembly.

[0012] Mechanical holding (or mechanical restraint) functions with the sudden dissipation of the reaction force. Typically, for example, during cutting, the working piston has not yet reached its stop position in the working direction when the reaction force dissipates; that is, the working piston can continue to move in the working direction. Mechanical holding prevents this possible continued movement, which is usually violent and results in a forceful impact on the hydraulic cylinder and possibly the entire working device containing the cylinder. Different designs can be specifically made for this type of mechanical holding, which will be explained further below. Until the reaction force dissipates, the movement of the working piston in the working direction is virtually unimpeded. The working process, preferably cutting or shearing, can be carried out as is known in such hydraulic cylinders or in hydraulic working tools with such cylinders. The adverse effects of the sudden movement of the working piston due to the disappearance of the reaction force, which could have resulted in a strong load on the hydraulic cylinder and the entire working tool, are greatly reduced or even eliminated. This significantly extends the life of the hydraulic cylinder or the working tool, especially if such load-bearing working processes are performed repeatedly or frequently with the hydraulic cylinder or working tool.

[0013] Mechanical coupling can exist between the working piston and the support, typically a hydraulic cylinder, or an intermediate piston still positioned between the working piston and the bottom of the cylinder, achieving a hold that is preferably only temporarily effective. This hold results in the hydraulic fluid, also preferably only temporarily effective, being encapsulated in the working space or generally the loading space between the working piston and the intermediate piston. This hydraulic fluid is under very high pressure shortly before the end of the working process. Pressures that can be involved are 200 bar or higher, for example, up to 600, 700, or 800 bar or even higher. Especially if the working process ends abruptly, for example, in the realm of cutting, by a blade moved by the working piston cutting through an object, the reaction pressure acting on the working piston dissipates almost abruptly. Although the hydraulic fluid is generally only slightly compressible, the high pressure results in the hydraulic fluid containing a large amount of stored energy, which causes a sudden movement of the working piston in the working direction and an impact on the hydraulic cylinder. The stored energy can also be caused or amplified by this, i.e., the hydraulic cylinder itself undergoes a certain degree of elastic expansion due to the aforementioned high pressure, which constitutes stored energy that must be dissipated when the reaction force dissipates.

[0014] Due to mechanical coupling, whether between the working piston and the intermediate piston, or between the working piston and the support in general, as previously described, the stored energy generates opposing loads between the working piston and the intermediate piston, or between the working piston and the support in general, at the sudden end of the working process. These loads can be said to cancel each other out due to mechanical coupling. There will be no sudden movement of the working piston and the intermediate piston, or, if necessary, the support in general.

[0015] Surprisingly, in hydraulic tools designed as cutting tools with hydraulic cylinders as described above, during the cutting of objects made of brittle materials, such as alloy steel rods or cast steel parts, not only is it possible for the tool to absorb virtually no or very little impact load when the object suddenly breaks at the end of the cutting process, but the cutting process itself can also be performed significantly more favorably. At the end of the cutting process, the cut fragments do not fly away; instead, the expected separation is achieved without the uncontrollable fragmentation characteristic.

[0016] Mechanical retention is achieved through mechanical coupling between the working piston and the support. The support can be configured in different ways.

[0017] Furthermore, it is preferred that the support is an intermediate piston. The intermediate piston is arranged between the working piston and the hydraulic cylinder, and in the working direction, between the bottom of the working piston and the hydraulic cylinder.

[0018] The support can also be constructed from the hydraulic cylinder itself, as explained in more detail below.

[0019] In a design with an intermediate piston, it is preferable that the intermediate piston is arranged in front of the working piston in the working direction, and the loading space is divided into a front space and a working space by the intermediate piston. The front space is formed between the bottom of the cylinder and the intermediate piston, and the working space is formed between the working piston and the intermediate piston. Hydraulic fluid can flow from the front space into the working space when the working space expands. The mechanical coupling between the working piston and the intermediate piston can compensate for the loading of the hydraulic fluid in the working space when the reaction force is canceled.

[0020] Regarding the method for shock absorption, in the design of a hydraulic cylinder with an intermediate piston, the intermediate piston is arranged in the working direction in the manner described above, preceding the working piston. The loading space is divided into a front space and a working space by the intermediate piston, wherein the front space is located between the cylinder bottom and the intermediate piston, and the working space is located between the working piston and the intermediate piston. During the working process, hydraulic fluid is introduced from the front space into the working space as the working space expands. Furthermore, when the reaction force is suddenly dissipated, the mechanical coupling between the working piston and the intermediate piston prevents the pistons from moving away from each other.

[0021] Furthermore, in designs with an intermediate piston, it is preferable that only the working piston acts on the object. The intermediate piston is essentially housed freely within the hydraulic cylinder, except in any case where it forms a mechanical coupling with the working piston in the direction toward the bottom of the cylinder at the end of the working process.

[0022] Regarding mechanical coupling, the intermediate piston has a coupling protrusion that works in conjunction with the coupling stop of the working piston. This coupling protrusion can vary in design. One approach involves a shoulder-shaped protrusion that reaches the rear-engaging, stepped enlargement of the working piston.

[0023] However, threaded components, such as those with very large pitches, like in the case of a drill bit, can also be involved, with the threaded component housed in a corresponding threaded opening of the working piston. At the start of the working process, when the working space is expanded by pumping hydraulic fluid into it, this in this embodiment may cause rotational movement of the intermediate piston. At the end of the working process, the sudden release of pressure causes a tendency for the intermediate and working pistons to move abruptly in a sense of separation. Furthermore, due to the inertia of the intermediate piston in its opposite direction of rotation, this tendency for sudden movement results in a preferably temporary, momentary blockage between the threaded protrusion of the intermediate piston and the threaded receptacle of the working piston. This also achieves a desired, albeit rigid, coupling between the intermediate pistons at the point of sudden end of the working process. Advantageously, this can be achieved regardless of the relative distance between the working and intermediate pistons during the working process.

[0024] Conversely, a coupling protrusion in the sense of the shoulder and a stop in the sense of the step are necessary to achieve the desired effect, namely, to form a stop before the end of the working process. For this purpose, a stop can be defined based on a certain minimum stroke of the working piston. The minimum stroke is chosen such that it is significantly shorter than the stroke typically reached at the end of the working process. For example, the stroke typically reached at the end of the stroke may be equivalent to 80% to 90% of the maximum stroke. Alternatively, the minimum stroke may be 40% to 70% of the maximum stroke.

[0025] If the minimum stroke is reached, the working piston preferably continues to move in the working direction. In this case, it moves together with the intermediate piston. In this case, from the moment the minimum stroke is reached, the working piston and the intermediate piston move synchronously in the working direction.

[0026] More specifically, the coupling protrusion can penetrate the loading surface of the working piston. A stop device can be correspondingly constructed inside the working piston. The working piston can have an opening, preferably a blind opening, into which the protrusion of the intermediate piston extends. The protrusion can have a stop shoulder.

[0027] In another possible design, the protrusion can have the aforementioned spindle configuration. The spindle nut can also be arranged in the working direction behind the loading surface of the working piston. The spindle nut is preferably fixedly connected to the working piston, and if necessary, even integrally constructed. However, it can also be rotatably housed within the working piston. In this case, it is not necessary for the spindle itself, or, if necessary, an intermediate piston connected to the spindle, to be rotatable, or in any case, to rotate during operation. This design is particularly advantageous if the protrusion is coupled, and if necessary, the spindle is directly fixed within the hydraulic cylinder and there is no intermediate piston.

[0028] Preferably, in any case, the coupling stop is constructed behind the loading surface in the loading direction.

[0029] The intermediate piston can be preloaded into a position spaced apart from the working piston before or outside the working process begins. This allows the working space to be safely filled with hydraulic fluid during operation, with the working piston and intermediate piston spaced as desired, until, for example, the stop position is reached. However, preload is preferably not required.

[0030] In further detail, the intermediate piston may have an opening equipped with a valve, preferably a valve that can be controlled between an open and closed position, to allow hydraulic fluid to flow from the working space to the front space. This valve is preferably easily openable in the direction toward the working space, but conversely, cannot be opened or can only be opened under special conditions in the direction toward the front space.

[0031] Furthermore, it is preferable that the valve reduces the throughput of hydraulic fluid in the closed position compared to the open position. In this case, the valve is not completely closed. When the working process ends, for example due to a sudden interruption of the object being worked on, the action of the hydraulic fluid under high pressure in the workspace still ceases because the hydraulic fluid cannot release pressure abruptly. However, the reduced throughput allows for a time-delayed and extended pressure release, thus dissipating the stored energy in the workspace without causing significant damage to the connected working tool. Here, without the above measures, the suddenly disappearing load acts in a very short time, typically within milliseconds, while with the design described herein, it can be extended to tens of milliseconds, for example, 20 to 40 milliseconds, while the maximum load of the hydraulic cylinder is decisively reduced until the maximum load is no longer perceptible.

[0032] Furthermore, it can be specified that the valve can be controlled to the open position by a stop at the bottom of the cylinder. A larger second open position may be involved if necessary. If, after the said working process is completed, the hydraulic fluid flows back to, for example, the hydraulic tank of the working tool, this can be caused by a check valve, for example, being controlled to the open position, wherein the automatic opening of the check valve may also depend on a determined pressure reached (e.g., see WO 99 / 019947 A1 or US 6 276 186 B1), causing the working piston and intermediate piston to move back towards the bottom of the cylinder. This typically occurs due to a return spring, which is supported on the hydraulic cylinder and acts on the working piston. Accordingly, the intermediate piston reaches the bottom of the cylinder after a certain, relatively short displacement. Through the control of the valve in the intermediate piston, which causes this to the (larger) open position, the hydraulic fluid can flow back from the working space more quickly. The working space shrinks here as the working piston moves closer to the intermediate piston again.

[0033] The valve is preferably preloaded in its closed position, for example, by a spring.

[0034] Alternatively or additionally, the intermediate piston may be provided with a clearance opening to the inner surface of the hydraulic cylinder to allow hydraulic fluid to flow from the pre-workspace to the working space. In this design, it may also be specified that, preferably, the valve constructed in the intermediate piston does not allow hydraulic fluid to flow from the working space to the pre-workspace in its closed position. In the event that the working process terminates abruptly, the hydraulic fluid can therefore only flow into the pre-workspace through the clearance opening. This process is also damped and prolonged in time due to the clearance effect, thus advantageously enabling the gentle dissipation of the desired stored energy.

[0035] The intermediate piston is also preferably capable of being loaded with a retaining force independently of the working force, which assists the hydraulic fluid to flow through the intermediate piston into the working space to expand the working space. The retaining force can be achieved, for example, by the aforementioned spring support of the intermediate piston on the working piston. This spring support tends to cause the working piston to move further and further away from the intermediate piston during the working process. However, at least in embodiments where the gap opening between the inner surface of the hydraulic cylinder and the intermediate piston is not significant, this retaining force can also be constituted by frictional forces between the intermediate piston and the inner surface of the hydraulic cylinder, for example, frictional forces arising from the surrounding seal of the intermediate piston that interacts with the inner surface of the hydraulic piston.

[0036] Of course, the retaining force allows the intermediate piston to move in the working direction under any circumstances. In embodiments with shoulder-shaped protrusions and stepped enlargements, this movement preferably occurs before the rigid coupling between the working piston and the intermediate piston. During operation, the intermediate piston can at least slightly move away from the bottom of the cylinder. Preferably, no movement of the intermediate piston occurs before the rigid coupling is formed between the working piston and the intermediate piston. During operation, the intermediate piston can remain against the bottom of the cylinder until then, or even against the working piston beforehand. Regarding the bottom of the cylinder, protrusions with, for example, rib-like or bolt-like structures can be formed on the working piston, which ensure that hydraulic fluid reaches the entire loading surface of the intermediate piston.

[0037] Preferably, at the start of the working process, the working piston is already positioned at a certain distance from the intermediate piston. More preferably, the working piston does not directly contact the intermediate piston, but is instead connected by hydraulic fluid that is already in the working space at the start of the working process.

[0038] In one of the above embodiments, the hydraulic working tool is correspondingly equipped with a hydraulic cylinder.

[0039] As mentioned above, this hydraulic working tool can be designed in particular as a cutting tool.

[0040] Typically, such hydraulic tools have a storage space for hydraulic fluid, which is pumped from this storage space into a hydraulic cylinder by a pump, preferably driven by an electric motor, to perform the working process. A control device may also be provided, for example, to move the aforementioned check valve to the open position when the pressure drops at the beginning of what is considered the end of the cutting process in a cutting tool, so that hydraulic fluid can flow from the hydraulic cylinder back to the storage space. It is particularly preferable that such tools are equipped with an accumulator for the operation of the electric motor.

[0041] Regarding the method for shock absorption, in the design of the hydraulic cylinder as described above, or a hydraulic working tool having a corresponding hydraulic cylinder, mechanical coupling with the working piston prevents the intermediate piston from moving relative to the working piston towards the bottom of the cylinder when the working force is suddenly dissipated. This also effectively prevents the working piston and the intermediate piston from moving relative to each other in opposite directions.

[0042] Regarding the support, the working piston can also be mechanically coupled to the support via a spindle assembly. The spindle assembly can be fixed to the intermediate piston for this purpose. However, it can also be fixed to the hydraulic cylinder itself, preferably at the bottom of the cylinder.

[0043] In further detail, the spindle assembly may be specified as rotatable. In this case, it is also preferable to provide a spindle nut in the working piston, and the spindle assembly can move axially in the working direction relative to this nut. Here, the spindle assembly may be stationary while the spindle nut is rotatable, or the spindle assembly may be rotatable while the spindle nut is stationary.

[0044] The spindle assembly can be rotated by rotating a corresponding part of the intermediate piston or hydraulic cylinder. However, the spindle assembly can also be rotatably fixed within a corresponding part of the intermediate piston or hydraulic cylinder.

[0045] Furthermore, the spindle assembly can be stationary within an intermediate piston or hydraulic cylinder. In this case, the spindle nut is rotatably housed within the working piston. To minimize friction, in further detail, the spindle nut can be held away from its stop surface, which ultimately functions when the reaction force is released, by a spring element. In a section inclined to the longitudinal axis constituting the working direction, the stop surface can also be configured to extend obliquely. Attached Figure Description

[0046] The present disclosure is now described with reference to the accompanying drawings, which only illustrate embodiments. In the drawings:

[0047] Figure 1 A longitudinal section is shown through the hydraulic cylinder of the first embodiment together with the working head, before the start of the working process;

[0048] Figure 2 Showing according to Figure 1 The view at the end of the work process;

[0049] Figure 3 Shown in accordance with Figure 2 An enlarged view of the valve located in the middle piston forming the support;

[0050] Figure 4 Showing according to Figure 3 The view, in accordance with Figure 1 In the position;

[0051] Figure 5 Showing according to Figure 1 The view, second embodiment;

[0052] Figure 6 The second embodiment is shown at the end of the working process;

[0053] Figure 7 Shown in accordance with Figure 6 The valve in the intermediate piston of the second embodiment;

[0054] Figure 8 Shown in accordance with Figure 5The valve in the intermediate piston of the second embodiment;

[0055] Figure 9 Another implementation method is shown according to Figure 1 The view shows the intermediate piston constrained in the spindle nut of the working piston by the spindle;

[0056] Figure 10 Showing according to Figure 9 The view shows that the support is formed by a hydraulic cylinder;

[0057] Figure 10a Show Figure 10 A magnified view of the central region Xa;

[0058] Figure 11 A schematic diagram of a complete hydraulic working tool is shown;

[0059] Figure 12 A schematic diagram of a check valve is shown. Detailed Implementation

[0060] First refer to Figure 11 The hydraulic working tool 1 is shown and described. In this embodiment, the hydraulic working tool 1 is designed as a manual tool. It preferably has an accumulator 2, an electric motor 3, and preferably a transmission device 4 and a pump 5. Hydraulic fluid can be pumped from a storage space 7 into a hydraulic cylinder 6 via the pump 5.

[0061] By only illustrative purposes Figure 11 The check valve 8 shown in the figure, which either automatically enters the open position or can be controlled to the open position, allows hydraulic fluid to flow back from the hydraulic cylinder 6 to the storage space 7 after the working process is completed.

[0062] The check valve 8 is located externally in the hydraulic fluid return line and positioned upstream of the storage space 7 in the working direction R of the working piston 10. The hydraulic fluid return line may at least partially overlap with the hydraulic line 22.

[0063] In the preferred rod-shaped design of the hydraulic working tool 1, a gripping area can be formed that surrounds the motor 3 and / or the transmission device 4 and / or the pump 5.

[0064] In addition, a control switch 9 can be set, which corresponds to the grasping area.

[0065] Reference Figures 1 to 4 The first embodiment is shown.

[0066] The working piston 10 and the intermediate piston 11 are arranged in the hydraulic cylinder 6.

[0067] The working piston 10 has a loading surface 12. A loading space is formed between the loading surface 12 and the inner surface 13 of the hydraulic cylinder 6, which is divided into a front space 14 and a working space 15 by the intermediate piston 11.

[0068] The working force used to perform the working process can be transmitted through the working piston 10 via the piston rod 16.

[0069] As can be seen in the embodiment, the working head 17 connected to the hydraulic cylinder 6 is designed as a cutting tool.

[0070] In further detail, the preferred active first blade 18 is connected to the piston rod 16 and moves relative to the fixed second blade 19 in the working head 17 during the movement of the working piston 10. An object 20, in the embodiment, such as a steel bolt, may be accommodated between the first and second blades 18, 19 for cutting.

[0071] The front space 14 in its initial state is as follows Figure 1 The device is very small and is located between the bottom 21 of the cylinder and the corresponding surface of the intermediate piston 11. Hydraulic fluid can be drawn from the storage space into the pre-positioning space 14 via the hydraulic line 22 through the pump 5 described above, and from there introduced into the working space 15 through the valve 23 arranged in the intermediate piston 11. Here, during the execution of the working process, rising hydraulic pressure is also generated in the working space 15, which causes the working space 15 to continuously expand as the working piston 10 moves in the working direction R.

[0072] The intermediate piston 11 has a coupling protrusion 24 to form a support G for the intermediate piston 11, and the coupling protrusion 24 is configured to interact with the coupling stop 25 of the working piston 10.

[0073] In this first embodiment, and preferably, the coupling protrusion 24 is a radially outwardly pointing protrusion extending transversely to the central axis x of the hydraulic cylinder 6. The radial protrusion can be stopped in the working piston 10 by a stepped tapering portion, preferably the coupling stop 25 is preferably configured as such a stepped tapering portion.

[0074] exist Figure 2 In the middle position, the coupling protrusion 24 is located in the stop at the coupling stop 25.

[0075] The coupling protrusion 24 is formed, in the embodiment and preferably, by the region, preferably the end region, of the intermediate piston rod 26 connected to the intermediate piston 11. The intermediate piston rod 26, and therefore the coupling protrusion 24, passes through the opening 50 of the loading surface 12 of the working piston 10. In the embodiment and preferably, the coupling stop 25 is constructed on the loading surface 12 in the loading direction, which coincides with the working direction R of the movable blade 18 moving toward the fixed blade 19.

[0076] During the execution of the working process, hydraulic fluid flows into the working space 15 through the pre-positioned space 14 and valve 23, causing the working piston 10 to move from the position specified by the valve. Figure 1 Move the position according to Figure 2 In its position. At the same time, the middle piston 11 also moves from according to... Figure 1 Move the position according to Figure 2 In its position. Clearly, during operation, the intermediate piston 11 moves with a shorter stroke than the working piston 10. However, the front space 14 also expands during operation.

[0077] If the working piston 10 travels relative to the intermediate piston 11 such that the initial distance 'a' between the coupling protrusion 24 and the coupling stop 25 has been used, i.e., the coupling protrusion 24 stops at the coupling stop 25, then the minimum stroke of the working piston 10 has been reached. After this, the working piston 10 normally continues to move along the travel direction R. However, the intermediate piston 11 also moves along the working direction R by being dragged along by the working piston 10. The working piston 10 and the intermediate piston 11 then travel synchronously after reaching their minimum stroke.

[0078] At the end of the working process, shortly before object 20 is cut in this embodiment, the working space 15 is filled with hydraulic fluid under very high pressure, in any case several hundred bar, for example 600 to 800 bar. The corresponding counter-pressure is applied from the first blade 18 and transmitted through the piston rod 16 to the working piston 10.

[0079] If, for example, due to a continuous cutting process, the object 20 suddenly breaks, the counterpressure is suddenly released, and the stored energy of the hydraulic fluid in the working space 15 between the working piston 10 and the intermediate piston 11, as well as the cylinder wall of the hydraulic cylinder 6 that defines the boundary of the working space 15 if necessary, can also be suddenly released without any preventative measures taken, and in principle, cause damage. Through the mechanical coupling provided for this purpose between the working piston 10 and the intermediate piston 11, the released stored energy results in a force being applied to the surface of the intermediate piston 11 facing the working piston 10 (the upper surface in the embodiment drawings) and the loading surface 12 of the working piston 10. Because the coupling protrusion 24 stops at the coupling stop 25 in this position, the intermediate piston 11 and the working piston 10 cannot move away from each other. The sudden dissipation of energy of the hydraulic fluid in the working space 15 is hindered. The forces acting in opposite directions on the working piston 10 and the intermediate piston 11 effectively cancel each other out.

[0080] Valve 23 is preferably preloaded in its closed position, for example, by a valve spring 34, as shown in the accompanying drawings. However, without such preload, valve 23 is also forced into the closed position by a sudden release of back pressure.

[0081] exist Figures 1 to 4 In the embodiments, valve 23 is preferably designed as follows, see Figure 3 That is, even in the closed position of the valve, a passage 27 remains, connecting the pre-positioned space 14 and the working space 15. This passage 27 is so small that the effect on the hydraulic fluid included in the working space 15 at the point when object 20 is cut off is equivalent to an actual closure. This prevents sudden pressure release. However, it also allows the energy stored in the hydraulic fluid to be gently dissipated with time delay and damping through possible slight hydraulic fluid backflow, via the closed valve 23.

[0082] Since the check valve 8 opens as the working process ends, thereby releasing hydraulic fluid from the front space 14 back to the storage space 7, the intermediate piston 11 then moves towards the bottom of the cylinder 21 together with the working piston 10 until it again occupies the position according to... Figure 1 The location.

[0083] According to Figure 1 In the reflux position, valve 23 hits the bottom 21 of the cylinder and thus moves according to Figure 4 In the open location.

[0084] Specifically, valve 23 may have a protrusion 28 extending beyond the bottom surface of intermediate piston 11 in the direction of cylinder bottom 21. Valve 23 then impacts cylinder bottom 21 via the protrusion 28 and is thereby movable according to... Figure 4 In the open location.

[0085] In further detail, valve 23 includes a passage segment 29, which is preferably tubular as in the embodiment. The passage segment 29 is closed on its upper side by a closing portion 30, i.e., toward the working space 15. However, the passage segment 29 has one or more, preferably two radial channels 31, through which hydraulic fluid can flow according to… Figure 4 In its offset state, the hydraulic fluid flows almost unimpeded from the working space 15 back to the front space 14 through the channel in the working state, and from there into the storage space 7. The radial opening 41 of the channel segment 29 corresponding to the cylinder bottom 21 functions in the same way to allow the hydraulic fluid to flow back into the return pipe 42 that runs through the cylinder bottom 21.

[0086] The closed forming part 30 is based on Figure 3 In its closed state, valve 23 rests against a closing shoulder 32 constructed in the intermediate piston 11 almost throughout its entire circumference. The closing shoulder 32 is part of a port 33 in the intermediate piston 11, in which the passage section 29 and the closing forming part 30 are movably constrained.

[0087] However, the closed forming portion 30 and / or the closed shoulder portion 32 retain the previously mentioned channel 27 on a portion of the periphery, even according to Figure 3 In the closed state of valve 23, passage 27 also allows hydraulic fluid to flow slightly from working space 15 into front space 14.

[0088] The closed state of valve 23 is achieved, in the embodiment and preferably, by a valve spring 34 acting on the channel section 29. The channel section 29 may therefore have a stop shoulder 44, which may be formed by a retaining ring connected to the channel section 29, as in the embodiment. In the intermediate piston 11, the valve spring 34 may be supported on the stop shoulder 51 formed in the channel opening 43.

[0089] The valve spring 34 is preferably configured to act with such low force that even during the operation, when hydraulic fluid is pumped into the pre-position 14 and from there into the working space 15, the valve 23 can be moved to its open position and the hydraulic fluid can flow relatively freely through the intermediate piston 11 into the working space 15.

[0090] In this first embodiment, the intermediate piston 11 is preferably further provided with a surrounding sealing element 35, which acts between the intermediate piston 11 and the inner surface 13 of the hydraulic cylinder 6. This sealing element 35 also provides a certain frictional force, which provides a holding force as hydraulic fluid is pumped into the pre-positioned space 14 and from there into the working space 15, so that the working piston 10 is desired to move away from the intermediate piston 11 during continued pumping. The sealing element 35 may be, for example, an O-ring.

[0091] According to Figures 5 to 8 The second embodiment contains essentially the same conditions, except for the differences described below. Unless otherwise stated, the above description also applies.

[0092] Unlike the first embodiment, the intermediate piston 11 in this second embodiment is designed without a sealing element 35. Instead, a gap opening 36, not further visible in the figures, is provided between the intermediate piston 11 and the inner surface of the hydraulic cylinder 6. The gap opening 36 is preferably configured such that, during operation, although hydraulic fluid can flow from the front space 14 into the working space 15 while simultaneously bypassing the intermediate piston 11, the hydraulic fluid essentially flows into the working space 15 through the valve 23, as in the first embodiment described. After the operation is completed, the hydraulic fluid can flow from the working space 15 into the front space 14 through the gap opening 36 with a strongly throttled flow. The gap opening 36 is further configured such that, during operation, the hydraulic fluid flowing through the gap opening 36 is practically negligible compared to the hydraulic fluid flowing through the valve 23.

[0093] To achieve the desired holding force acting on the intermediate piston 11 in this embodiment, the intermediate piston 11 is loaded by a pressure spring 37 acting between the working piston 10 and the intermediate piston 11. More specifically, the pressure spring 37 is received in a receiving space 38, preferably designed as a blind bore, in the piston rod 16. The pressure spring 37 acts on the facing end face of the intermediate piston rod 26 in this embodiment, and preferably on the coupling protrusion 24 of the intermediate piston 11 in this embodiment.

[0094] Compared to Figure 2 , Figure 6 The design of the second embodiment is presented at the end of the work process. This actually constitutes... Figure 2 The same conditions. With Figure 2 The implementation method is different in that when the reaction force is suddenly dissipated, the hydraulic fluid discharged from the working space 15 actually flows out only through the gap opening 36.

[0095] In this second embodiment, preferably, if valve 23 is as follows: Figure 7 and 8 The configuration shown is without outlet 27, thus constituting outflow solely through gap opening 36 in all cases. Specifically, according to... Figure 3 When valve 23 is in the closed state, a complete seal is formed in terms of the flow of hydraulic fluid from the working space 15 to the front space 14. Alternatively, in this embodiment, valve 23 may also be designed according to the first embodiment.

[0096] Reference Figure 9 Alternative implementations are shown, but only those based on [specific implementation details] are illustrated. Figure 1 or Figure 5 The initial state. Figure 9 The implementation methods will also differ only in that they are described below. Furthermore, the explanations for the first two implementation methods will apply.

[0097] exist Figure 9 In this implementation, the fundamental feature is that the intermediate piston 11 is constructed with a spindle component 39, which works in conjunction with the spindle nut 40 constructed in the working piston 10.

[0098] During operation, the spindle assembly 39 can first move through the spindle nut 40 when the intermediate piston 11 rotates, wherein, as described, at the beginning of the operation, the intermediate piston 11 also moves away from the working piston 10, i.e., the working space 15 becomes larger.

[0099] In this embodiment, a further preferred design for the intermediate piston 11 is according to the second embodiment, i.e., without the sealing element 35. This makes it easier to rotate the intermediate piston 11 within the hydraulic cylinder 6 in possible specific related embodiments.

[0100] Since the required holding force can be set simultaneously through the combined action of the spindle nut 40 and the spindle component 39, the valve 23 can still be constructed in the same manner as in the first embodiment. However, alternatively, if a gap opening 36 as described in the second embodiment is provided between the intermediate piston 11 and the inner surface 13 of the hydraulic cylinder 6, the valve 23 can also be constructed in accordance with the second embodiment.

[0101] The spindle assembly 39 accordingly has a spindle thread with a very large pitch, for example, in the range of 30 to 60 degrees or greater. The spindle nut 40 is designed to have a corresponding mating thread.

[0102] The spindle nut 40 can be arranged in the working piston 10 in a torsion-resistant manner. Preferably, it is also integrally constructed with it.

[0103] The main shaft assembly 39 can also be directly arranged in the cylinder bottom 21. In this case, the intermediate piston 11 can be completely eliminated.

[0104] The spindle assembly 39 can be rotatably housed in the cylinder bottom 21, or it can be fixedly connected to the cylinder bottom 21, i.e., a torsion-resistant connection.

[0105] In embodiments with intermediate piston 11, spindle component 39 may also be rotatably housed in intermediate piston 11.

[0106] With the spindle assembly 39 fixedly housed, the spindle nut 40 can be movably housed in the working piston 10, that is, it can rotate about the axis of the spindle assembly when the spindle assembly moves relative to the spindle nut.

[0107] Reference Figure 10 Another implementation is shown, particularly the support that may be formed by a hydraulic cylinder.

[0108] In this embodiment, a main shaft component 39 is also provided, which is directly anchored in the cylinder bottom 21. As shown in the figure, it can be helically anchored in the cylinder bottom 21.

[0109] In the illustrated embodiment, the spindle assembly 39 is not rotatably anchored in the cylinder bottom 21 for operation.

[0110] In this embodiment, the spindle nut 40 is movably, specifically rotatably, housed within the working piston 10. The spindle nut 40 is held between a front stop 45 along the working direction R and a rear stop 46 along the working direction R. As shown, the rear stop 46 is preferably formed by a screw-in component.

[0111] The stop surface 47 of the rear stop 46 and, preferably, the corresponding mating surface 48 of the spindle nut 40, relative to the longitudinal axis of the hydraulic cylinder 6 or relative to... Figure 10 The working direction R in the cross-sectional view is inclined and extended. This allows for the formation of advantageous, self-locking surface pairs when these surfaces are stacked and force-loaded upon sudden loss of reaction force. This effectively prevents the spindle nut 40 from rotating instantaneously upon loss of reaction force.

[0112] However, in order to prevent significant damage to the spindle nut 40 during the movement of the working piston 10, it is preferred and specified in the embodiments that the spindle nut 40 is disengaged from the rear stop 46 by a spring element 49, see Figure 10a A magnified view in the image.

[0113] Figure 12 The above-mentioned check valve 8 is schematically shown in the figure.

[0114] The check valve 8 is substantially disposed in the area between the pre-positioning space 14 and the storage space 7 and is substantially composed of a valve piston 52 having a centrally located, tapered needle tip 53 at one end to form a partial piston surface (effective seat valve surface). This partial piston surface is substantially smaller than the total piston surface 54 and is defined by the diameter of the orifice 55 connecting to the pre-positioning space 14. The latter, in the initial closed position, as... Figure 12 The needle tip 53 is shown as the closure.

[0115] On the back side, the valve piston 52 is loaded by the pressure spring 56, thereby causing the needle tip 53 to be squeezed relative to the orifice 55 by a force that together determines the maximum trigger pressure.

[0116] To ensure the proper functioning of the working tool 1, it is desirable that the check valve 8 be triggered automatically or even intentionally. For example, it can be specified that the check valve 8 opens at a pressure of, for example, 500 or 600 bar. This maximum pressure is defined by a very small portion of the piston area or the cross-sectional area of ​​the orifice 55 projected by the needle tip 53 onto the orifice 55 and by the contact pressure of the pressure spring 56 on the valve piston 52.

[0117] If the oil pressure now exceeds the predetermined maximum value, the valve piston 52 moves out of its arrangement close to the bore 55 against the force of the pressure spring 56, after which a significantly larger piston surface, namely the total piston surface 54 of the valve piston 52, suddenly comes into play. By moving the valve piston 52 backward, the discharge port 58 arranged in the cylinder 57 that houses the valve piston 52 is at least partially opened, allowing hydraulic fluid to flow back into the storage space 7.

[0118] The user of the working tool 1 can also open the check valve 8 by means of the user's intention, for example by arranging a manually operable lever that can be accessed from the outside, for example when arranged in the handle area, directly or indirectly acting on the valve piston 52. When the lever is operated accordingly, the valve piston 52 is lifted off its seat against the restoring force of the pressure spring 56, so that the orifice 55 and the outlet 58 are released so that the hydraulic fluid can flow back into the storage space 7.

[0119] List of reference numerals

[0120] 1 hydraulic working tool 28 protrusions

[0121] 2 accumulators, 29 channels section

[0122] 3 motors 30 closed forming section

[0123] 4 transmission devices, 31 channels

[0124] 5 pumps 32 closed shoulder

[0125] 6 hydraulic cylinders with 33 ports

[0126] 7 storage space 34 valve springs

[0127] 8 Check Valve 35 Sealing Element

[0128] 9. Operating switch 36. Gap opening

[0129] 10 working pistons, 37 pressure springs

[0130] 11 intermediate pistons, 38 occupancy space

[0131] 12 loading surfaces 39 spindle components

[0132] 13 Inner Surface 40 Spindle Nut

[0133] 14 front-facing spaces 41 openings

[0134] 15 working space, 42 return pipes

[0135] 16 piston rod, 43 channel opening

[0136] 17 working head 44 stop shoulder

[0137] 18 Movable first blade 45 front stop

[0138] 19 Fixed second blade 46 Rear stop

[0139] 20 objects 47 stop surfaces

[0140] 21 cylinder bottom 48 mating surface

[0141] 22 Hydraulic lines 49 Spring elements

[0142] 23 valves, 50 port

[0143] 24 Coupler protrusions 51 Stop shoulder

[0144] 25 Coupled Stop

[0145] 26. Initial distance of intermediate piston rod a

[0146] 27-channel x centerline

[0147] G bracket

[0148] R working direction

Claims

1. A device having a hydraulic cylinder (6) and a hydraulically loaded working piston (10), wherein, The working piston (10) is movable within the hydraulic cylinder (6) and configured to transmit working force to the object (20) outside the hydraulic cylinder (6) in the event of a reaction force. The working piston (10) also has a loading surface (12) that defines the boundary of the loading space formed between the working piston (10) and the hydraulic cylinder (6) along the working direction (R) of transmitting the working force. The device also includes a hydraulic fluid disposed within the hydraulic cylinder (6), which enters the loading space, causing the loading space to increase and acting on the working piston (10) to move the working piston along the working direction (R) toward the loading surface (12). The working piston (10) is characterized by being configured to move in the working direction before reaching a stop position when the reaction force is dissipated. The mechanical coupling between the support (G) and the working piston (10) is mechanically maintained, thereby preventing additional movement of the working piston (10) in the working direction (R) which would occur without a reaction force to dissipate it. The support (G) is an intermediate piston (11) arranged in the working direction (R) ahead of the working piston (10) and the intermediate piston (11) has a coupling protrusion (24) for engaging with the coupling stop (25) of the working piston (10). Alternatively, the support (G) is formed by a hydraulic cylinder (6), wherein the working piston (10) and the hydraulic cylinder (6) are mechanically coupled by a spindle assembly (39), wherein the spindle assembly is fixedly connected inside the hydraulic cylinder, and a spindle nut rotatably accommodated in the working piston engages with the spindle assembly. The working piston and the hydraulic cylinder are mechanically coupled by the spindle assembly and the spindle nut.

2. The apparatus according to claim 1, characterized in that, The working piston (10) and the intermediate piston (11) are mechanically coupled through the main shaft assembly (39).

3. The apparatus according to claim 1, characterized in that, The spindle assembly (39) is rotatable.

4. The apparatus according to claim 1, characterized in that, The spindle assembly (39) is stationary.

5. The apparatus according to claim 1, characterized in that, The spindle assembly (39) is fixed in the intermediate piston.

6. The apparatus according to claim 1, characterized in that, The spindle assembly (39) is fixed in the hydraulic cylinder.

7. A device having a hydraulic cylinder (6) and a hydraulically loaded working piston (10), wherein, The working piston (10) is movable within the hydraulic cylinder (6) and configured to transmit working force to the object (20) outside the hydraulic cylinder (6) in the event of a reaction force. The working piston (10) has a loading surface (12) that defines the boundary of the loading space formed between the working piston (10) and the hydraulic cylinder (6) along the working direction (R) of transmitting the working force. The device also includes hydraulic fluid disposed within the hydraulic cylinder (6), wherein the hydraulic fluid enters the loading space, causing the loading space to increase and acting on the working piston (10) to move the working piston along the direction of the reaction force. The working piston (10) moves in the working direction (R) toward the loading surface (12), characterized in that the working piston (10) is configured to be mechanically held in the working direction by mechanical coupling between the working piston (10) and the support (G) before reaching the stop position when the reaction force is dissipated, thereby preventing additional movement of the working piston (10) in the working direction (R) that would occur when there is no reaction force dissipation, wherein the support (G) is an intermediate piston (11) or formed by a hydraulic cylinder (6) and has a coupling protrusion (24) constructed on the support (G) and the working piston (10) has a coupling stop (25).

8. The apparatus according to claim 7, characterized in that, The working piston (10) is mechanically coupled to the intermediate piston (11) or hydraulic cylinder (6) via the main shaft assembly (39).

9. The apparatus according to claim 1 or 7, characterized in that, The loading space is divided into a front space (14) and a working space (15) by an intermediate piston (11). The front space (14) is formed between the bottom (21) of the hydraulic cylinder (6) and the intermediate piston (11), and the working space (15) is formed between the working piston (10) and the intermediate piston (11). The hydraulic fluid is configured to flow from the front space (14) into the working space (15) to expand the working space (15). The working piston (10) and the intermediate piston (11) are mechanically coupled to compensate for the effect of the hydraulic fluid in the working space (15) when the reaction force is dissipated.

10. The apparatus according to claim 1 or 7, characterized in that, In the design with intermediate piston (11), only the working piston (10) is used to act on the object (20) in the category of transmitting working force to the object.

11. The apparatus according to claim 1 or 7, characterized in that, The coupling protrusion (24) is constructed to penetrate the loading surface (12).

12. The apparatus according to claim 1 or 7, characterized in that, The coupling stop (25) is constructed in the loading direction after the loading surface (12).

13. The apparatus according to claim 1 or 7, characterized in that, The intermediate piston (11) is preloaded at a position spaced apart from the working piston (10).

14. The apparatus according to claim 1 or 7, characterized in that, The intermediate piston (11) has a passage (33) and also has a valve (23) arranged in the passage (33), wherein the valve (23) is movable between an open position and a closed position.

15. The apparatus according to claim 14, characterized in that, The valve (23) is designed to allow hydraulic fluid to flow from the front space (14) to the working space (15).

16. The apparatus according to claim 14, characterized in that, The valve (23) is configured to reduce the throughput of hydraulic fluid in the closed position compared to the open position.

17. The apparatus according to claim 14, characterized in that, The valve (23) can be controlled to the open position by a stop on the bottom of the cylinder (21).

18. The apparatus according to claim 14, characterized in that, Valve (23) is pre-tightened in its closed position.

19. The apparatus according to claim 1 or 7, characterized in that, The intermediate piston (11) has a gap opening (36) relative to the inner surface (13) of the hydraulic cylinder (6).

20. The apparatus according to claim 1 or 7, characterized in that, The intermediate piston (11) can be independently of the working force to retain the load, which assists in the flow of hydraulic fluid through the intermediate piston (11) into the working space (15) to expand the working space (15).

21. The apparatus according to claim 20, characterized in that, This holding force allows the intermediate piston (11) to move in the working direction (R).

22. A combination of the device according to any one of the preceding claims with a hydraulic tool (1), the hydraulic tool having a working head (17).

23. The combination according to claim 22, characterized in that, Hydraulic tools are cutting tools.

24. A method for absorbing the impact of a hydraulically loaded working piston (10) movable within a hydraulic cylinder (6), the working piston being used to transmit a working force to an object (20) outside the hydraulic cylinder (6) in the event of a reaction force, wherein, The working piston (10) has a loading surface (12) that defines a loading space between the working piston (10) and the hydraulic cylinder (6) in the working direction (R) in which the working force is transmitted. The hydraulic fluid is introduced onto the loading surface (12) to expand the loading space in order to move the working piston (10) in the working direction (R). The feature is that, when the reaction force is suddenly dissipated, the working piston (10) is mechanically held in the working direction before reaching the stop position, preventing further movement of the working piston (10) in the working direction (R) that would be possible without the reaction force dissipating. This obstruction is achieved through a mechanical coupling between the working piston (10) and the support (G). An intermediate piston (11) is provided as a support and is arranged in front of the working piston (10) in the working direction. The loading space is divided by the intermediate piston (11). The system consists of a front space (14) and a working space (15), wherein the front space (14) is between the bottom (21) of the cylinder and the intermediate piston (11), and the working space (15) is between the working piston (10) and the intermediate piston (11). Hydraulic fluid is introduced from the front space (14) into the working space (15) as the working space (15) expands, and when the reaction force is suddenly dissipated, the mechanical coupling between the working piston (10) and the intermediate piston (11) prevents the movement of these pistons (10, 11) from moving away from each other. Alternatively, the hydraulic cylinder (6) is configured as a support and the mechanical coupling between the working piston (10) and the hydraulic cylinder (6) is achieved through a spindle assembly (39), wherein the spindle assembly is fixedly connected inside the hydraulic cylinder, and the spindle nut, which is rotatably accommodated in the working piston, cooperates with the spindle assembly. The working piston and the hydraulic cylinder are mechanically coupled through the spindle assembly and the spindle nut.

Images