Gripper system with hydraulic device

Abstract

Disclosed herein is a work implement for a machine designed to grip material or objects, comprising a frame (6), a first gripper part (2) and a second gripper part (4), a master actuator (10) having a first master port (40) on the piston side and a second master port (42) on the rod side, and a slave actuator (12) having a second master port (42) on the rod side, and a hydraulic device (8, 8 '), the invention relates to a gripper (1) comprising a frame (6), a slave actuator (20) having a first slave port (44) on the piston side and a second slave port (46) on the rod side, a first gripper part (2) pivotably coupled to the frame (6), a second gripper part (4) pivotably coupled to the frame (6), a master actuator (10) coupled to the frame (6) and the first gripper part (2), the first gripper member (2) is pivotable from the open position (36) to the closed position (38) and from the closed position to the open position. A slave actuator (12) is coupled to the frame (6) and to the second gripper member (4) for pivoting the second gripper member (4) from the open position (36) to the closed position (38) and from the closed position to the open position. The hydraulic device (8, 8 ') comprises a first side portion (28), a second side portion (30), and a hydraulic line (26) for interconnecting the first side portion (28) with the first master port (40) and the second master port (42), the first slave port (44) and the second slave port (46), and the second side portion (30). The hydraulic device further comprises a first relief valve (18) having a first relief pressure (p1) and a second relief valve (20) having a second relief pressure (p2). The master actuator (10) and the first pressure relief valve (18) are coupled in parallel, the slave actuator (12) and the second pressure relief valve (20) are coupled in parallel, and the master actuator (10) and the first pressure relief valve (18) are coupled in series with the slave actuator (12) and the second pressure relief valve (20), whereby the master actuator (10) and the first pressure relief valve (18) are coupled in parallel with the slave actuator (12) and the second pressure relief valve (20). The first pressure relief valve (18) and the second pressure relief valve (20) are arranged to open in the same direction from the first side portion (28) to the second side portion (30) or in the same direction from the second side portion (30) to the first side portion (28).

Description

Technical Field

[0001] This invention relates to the field of gripper or chuck systems used on construction or forestry machinery and / or in combination with quick-connectors, tool holders or tilting rotators connected to such machinery, and in particular to a hydraulic system associated with such gripper or chuck system. Background Technology

[0002] Typically, when using gripper systems for machinery, whether these systems are used to grab gravel via a bucket, grip logs (logging), or grip various components during construction, two hydraulic cylinders are involved to close and open the gripper. In the prior art, these two hydraulic cylinders are controlled and connected in parallel, utilizing different solutions to synchronize these cylinders because a pair of grippers needs to move synchronously. Typically, these parallel-connected hydraulic cylinders are of the same size.

[0003] One common problem with existing gripper systems is synchronization issues caused by uneven resistance or load on one of the grippers or jaws.

[0004] In the fields of grippers, gripper systems, forestry machinery, or clamshell grabs, asynchronous movement of two gripper components is particularly problematic due to the precision required to grasp materials or objects.

[0005] Different solutions have been adopted to address the synchronization problem in hydraulic actuators; however, these solutions are unrelated to the gripper system.

[0006] US 5682955 A discloses a blade control system including a directional control valve, a fluid regeneration valve, and a selection valve for selectively controlling fluid flow between a pump and first and second hydraulic cylinders, and between these cylinders. By positioning these valves in preselected operating positions, pressurized fluid from the pump is directed to the head chamber of the first cylinder, fluid discharged from the rod end chamber of the first cylinder is transferred to the head chamber of the second cylinder, and fluid discharged from the rod end chamber of the second cylinder is combined with the fluid directed to the head chamber of the first cylinder to provide two-stage fluid regeneration to increase the cylinder extension rate.

[0007] However, US 5682955 A does not discuss synchronization issues related to gripper systems, clamping systems, and working tools.

[0008] US 5110251 A provides another example, disclosing a hydraulic platform lift for use on trucks and truck trailers, the platform lift having two hydraulic cylinders, one on each side of the door. These cylinders are phased cylinders, one of which is proportionally larger than the other. The cross-sectional area of ​​the fluid in the rod end of the larger cylinder minus the area of ​​the rod equals the cross-sectional area of ​​the smaller cylinder. Connecting lines interconnect the rod end of the larger cylinder with the cap end of the smaller cylinder. A controller allows hydraulic fluid to be directed to either the cap end of the larger or smaller cylinder. For upward movement, hydraulic fluid is forced into the rod end of the smaller cylinder. This, in turn, forces hydraulic fluid through the connecting lines into the rod end of the larger cylinder, thereby lifting both pistons. For downward movement, hydraulic fluid is forced into the cap end of the larger cylinder, thereby forcing fluid out of the rod end of the larger cylinder and into the cap end of the smaller cylinder. This causes both cylinders to move downward. The platform lift also has a self-leveling feature, allowing the pistons to be level with each other by moving the platform to its highest position. The operating mechanism is located entirely on the side of the trailer. During use, the platform can apply a positive upward force or a positive downward force.

[0009] However, US 5110251 A does not discuss any synchronization issues related to the gripper system or the working tool. Summary of the Invention

[0010] This invention aims to improve the efficiency of supplying hydraulic fluid to a working tool comprising two hydraulic actuators arranged in a master / slave series flow relationship. More specifically, the object of this invention is to allow for the control of synchronized movement between the master and slave actuators of a gripping component in a mechanical working tool.

[0011] Another object of the present invention is to provide a hydraulic device that enables master and slave actuators to be synchronized in an extended position or a retracted position, or both.

[0012] These and other objectives are achieved through the invention as defined in the independent claims. Preferred embodiments are defined in the dependent claims.

[0013] The inventors of this invention have discovered that by connecting a first actuator, such as a hydraulic cylinder, and a second actuator, such as a hydraulic cylinder, in series, and by compensating for the volumes in the first and second actuators respectively, the synchronization in a gripper system or working tool can be improved to achieve optimal performance. In particular, the inventors have discovered that two actuators can be connected in series and in a master-slave relationship.

[0014] This invention employs a novel and different approach to synchronize the master and slave actuators controlling the gripping components. Instead of using complex components such as sensors, switching valves, or multi-way valves, a pressure relief valve is arranged in a novel and inventive hydraulic device to control the first and second gripping components.

[0015] According to one aspect of the invention, a working tool for machinery is provided, designed for gripping materials or objects. The working tool includes a frame, a first gripper component, and a second gripper component. The working tool also includes a master actuator and a slave actuator, the master actuator having a first master port on the piston side and a second master port on the rod side, and the slave actuator having a first slave port on the piston side and a second slave port on the rod side. The first and second gripper components are pivotally connected to the frame. The master actuator is connected to the frame and the first gripper component for pivoting the first gripper component from an open position to a closed position and from a closed position to an open position. The slave actuator is connected to the frame and the second gripper component for pivoting the second gripper component from an open position to a closed position and from a closed position to an open position.

[0016] The size of the main actuator can be set to absorb the full pressure or load of the hydraulic system.

[0017] If a hydraulic cylinder or hydraulic actuator is used, the cross-section or size of the piston of the master actuator can be larger than the cross-section or size of the piston of the slave actuator.

[0018] The working tool also includes a hydraulic system comprising a first side, a second side, a first relief valve having a first relief pressure, and a second relief valve having a second relief pressure, wherein the first and second relief valves are arranged to open in the same direction from the first side to the second side or from the second side to the first side. The hydraulic system also includes hydraulic lines for interconnecting various components in the system.

[0019] The hydraulic lines in the hydraulic device are arranged such that: -The main actuator and the first pressure relief valve are connected in parallel; - Connected in parallel from the actuator and the second pressure relief valve; and - The main actuator and the first pressure relief valve are connected in series with the slave actuator and the second pressure relief valve.

[0020] In an embodiment of the invention, the first pressure relief valve and the second pressure relief valve are arranged to open in a direction from the first side to the second side when the first pressure or the second pressure is reached, so that the first gripper component or the second gripper component can move synchronously to the closed position.

[0021] Since the working tool is usually in a closed position when not in use so as not to interfere with other tools or implements that may be connected to the machine, such as via a quick-connect unit, synchronization in the closed position can occur very easily and naturally when the working tool is retracted.

[0022] In another embodiment, the first and second pressure relief valves are arranged to open in a direction from the second side to the first side when the second pressure or the first pressure is reached, so that the first or second gripper component can move synchronously to the open position.

[0023] It may be advantageous for the opening positions of the first and second gripper components to be synchronized. For example, when a grappling hook or similar device grabs and unloads large stones, synchronization issues may arise during the material grabbing process (e.g., the stone itself), and the two grippers of the grappling hook need to be synchronized in their opening positions during the material release process.

[0024] According to one embodiment, the first side can be connected to a hydraulic fluid tank or a hydraulic fluid pump. If the first side is connected to a hydraulic fluid tank, the second side can be connected to a hydraulic fluid pump, or if the first side is connected to a hydraulic fluid pump, the second side is connected to a hydraulic fluid tank.

[0025] This can be achieved using a hydraulic device or a switching valve in a hydraulic system.

[0026] The ability to connect the first and second sides to a hydraulic fluid tank or pump makes the system more versatile and enables additional functions described herein.

[0027] The first and / or second side may be a port, connector, or outlet valve, etc.

[0028] In one embodiment, the main actuator and the first pressure relief valve are connected in series with the first side, and the actuator and the second pressure relief valve are connected in series with the second side.

[0029] In an embodiment of the invention, the master actuator and the slave actuator are in the extended state in the closed position. If the slave actuator is not synchronized with the master actuator in the closed position, the hydraulic fluid flows from the first side, which is the pump side in this case, via the first pressure relief valve—in this case, the first pressure relief valve is open because, due to the extension of the master actuator, it is no longer possible to pump hydraulic fluid into the master actuator via the first master port—to the first slave port to extend the slave actuator, and then flows from the second slave port to the second side connected to the hydraulic fluid tank.

[0030] The above describes the flow of hydraulic fluid used to achieve optimal performance and function in the closed position.

[0031] According to another embodiment, the master actuator and the slave actuator are in the extended state in the closed position. If the master actuator is not synchronized with the slave actuator in the closed position, hydraulic fluid flows from the first side through the first master port to the master actuator and from the second master port to the second pressure relief valve. In this case, the second pressure relief valve opens because, due to the extension of the slave actuator, hydraulic fluid can no longer be pumped into the slave actuator through the first slave port and flow from the second pressure relief valve to the second side connected to the hydraulic fluid tank.

[0032] The above describes the flow of hydraulic fluid used to achieve optimal performance and function when synchronized in the open position.

[0033] In this implementation, the first venting pressure is less than the second venting pressure.

[0034] This configuration ensures that the hydraulic fluid takes the correct flow path and also takes into account the different sizes of the master and slave actuators.

[0035] According to another embodiment of the invention, the hydraulic system further includes a third relief valve having a third relief pressure and a fourth relief valve having a fourth relief pressure, the third relief valve being connected in parallel with the main actuator and the first relief valve, and the fourth relief valve being connected in parallel with the slave actuator and the second relief valve, wherein the third relief valve and the fourth relief valve are designed to open in a direction from the second side to the first side, and wherein the first relief valve and the second relief valve are designed to open in a direction from the first side to the second side.

[0036] Using a third and fourth pressure relief valve in a hydraulic device or system can achieve synchronization between the closed and open positions, thereby making the work tools more versatile.

[0037] According to the embodiment, the main actuator, the first pressure relief valve and the third pressure relief valve are connected in series with the first side, wherein the slave actuator, the second pressure relief valve and the fourth pressure relief valve are connected in series with the second side.

[0038] The connections described above help guide the flow of hydraulic fluid in the correct manner and also help achieve the correct function while maintaining the series connection between the master actuator and the slave actuator.

[0039] In other embodiments, also according to the method of the present invention, the master actuator and slave actuator are in the retracted state in the open position. If, in the open position, the master actuator is not synchronized with the slave actuator, hydraulic fluid flows from the second side, which in this case is the pump side, via the fourth pressure relief valve—in this case, the fourth pressure relief valve is open because, due to the retraction of the slave actuator, hydraulic fluid can no longer be pumped into the slave actuator via the second slave port—to the second master port to retract the master actuator, and then from the first master port to the first side connected to the hydraulic fluid tank.

[0040] According to another embodiment, also according to the method of the present invention, the master actuator and the slave actuator are in the retracted state in the open position. If, in the open position, the slave actuator is not synchronized with the master actuator, hydraulic fluid flows from the second side, which in this case is the pump side, to the second slave port to retract the slave actuator, and then from the first slave port via a third pressure relief valve—in this case, the third pressure relief valve is open because, due to the retraction of the master actuator, hydraulic fluid can no longer be pumped into the master actuator via the second master port—to the first side connected to the hydraulic fluid tank.

[0041] The above two paragraphs describe the flow of hydraulic fluid used to achieve optimal performance and function in both the closed and open positions.

[0042] In this implementation, the third venting pressure is lower than the first venting pressure. Furthermore, the third venting pressure may be lower than the second venting pressure.

[0043] The specific specifications for the third and fourth relief pressures can be selected to achieve optimal performance and ensure proper functionality.

[0044] However, the first, second, third, and / or fourth relief pressures can also be selected differently, if the hydraulic system or hydraulic device requires such modification.

[0045] According to one embodiment, the first gripper component is a first gripper arm, and the second gripper component is a second gripper arm.

[0046] Using the first and second gripping arms ensures that objects can be gripped properly.

[0047] One of the first or second gripping arms may include a pair of gripping claws designed to receive the other gripping arm between them during the opening and closing of the first and second gripping arms. The gripping claws ensure symmetrical gripping of objects, thus allowing loads to be applied symmetrically to logs or lampposts, etc.

[0048] In implementation, the above-described working tools can be used together with a quick-connect unit or a tilting rotator.

[0049] As those skilled in the art will appreciate, the components and hydraulic devices according to the invention, and their preferred embodiments, are suitable for use with a variety of working implements. Such working implements may be buckets, grippers, grapples, crushers, such as concrete component crushers for demolition.

[0050] In another aspect of the invention, a method is provided for synchronizing two or more actuators used in a machine tool.

[0051] - The machinery can be any machinery, such as earthmoving machinery, vehicle-mounted jacks, loading cranes, demolition machinery, or other machinery including working implements with two or more actuators capable of withstanding uneven loads, such as earthmoving blades or forks of vehicle-mounted jacks.

[0052] - The working tool may include a master actuator, a slave actuator, a first side, a second side, and a hydraulic device.

[0053] - The master actuator may have a first master port located on the piston side and a second master port located on the rod side, and the slave actuator may have a first slave port located on the piston side and a second slave port located on the rod side.

[0054] - Both the first and second sides can be connected to a hydraulic pump or hydraulic tank, which can be achieved using a switching valve or a two-way valve.

[0055] - The hydraulic device may include at least a first pressure relief valve and a second pressure relief valve. The first pressure relief valve and the second pressure relief valve are preferably unidirectional and arranged to allow hydraulic fluid to flow from a first side to a second side, or from a second side to a first side.

[0056] - The hydraulic device may include hydraulic lines arranged such that: a main actuator and a first pressure relief valve are connected in parallel; a slave actuator and a second pressure relief valve are connected in parallel; and the main actuator and the first pressure relief valve are connected in series with the slave actuator and the second pressure relief valve.

[0057] The term "one-way" in this document refers to the fact that each of the corresponding valves—the first, second, third, or fourth relief valve—can be a valve that allows flow in only one direction. Such valves can have various styles, shapes, and designs, but the overall concept is the same. Alternatively, such valves can be called check valves, anti-return valves, etc.

[0058] The proposed method may include the following steps for guiding hydraulic fluid: - Connecting the first or second side to the hydraulic pump causes the first and second sets of actuators to extend; and If, in the closed position, the actuator is not synchronized with the master actuator, and thus the master actuator is fully extended, the hydraulic fluid flow is as follows: i. Starting from the first side, in this case the first side is the pump side; ii. Flow to the first pressure relief valve, in which case the first pressure relief valve opens because, since the main actuator is preferably fully extended, hydraulic fluid can no longer be pumped into the main actuator via the first main port; iii. Flow to the first slave port to extend the slave actuator; iv. Then it flows from the second port to the second side connected to the hydraulic fluid tank.

[0059] If, in the closed position, the master actuator is not synchronized with the slave actuator, and thus the slave actuator may be in the fully extended position, the hydraulic fluid flow will be as follows: v. Starting from the first side, in this case the first side is also the pump side; vi. The flow enters the main actuator through the first main port, causing the main actuator to extend; vii. Flow from the second main port to the second relief valve, in which case the second relief valve opens because, since the actuator is preferably fully extended, hydraulic fluid can no longer be pumped into the slave actuator via the first slave port; and viii. Flow from the second pressure relief valve to the second side connected to the hydraulic fluid tank.

[0060] In one embodiment of the above method, the proposed working tool includes at least one additional actuator, and the hydraulic device includes at least one additional pressure relief valve. In such an embodiment, the additional actuator is connected in parallel with at least one additional pressure relief valve. The additional pressure relief valve is unidirectional and arranged in a manner similar to that of the first and second pressure relief valves. The slave actuator and the additional actuator are connected in a manner similar to that of the master actuator and the slave actuator. This means that the additional actuator and the additional pressure relief valve are connected in series with the slave actuator and the second pressure relief valve, and the hydraulic device includes a conduit connecting the piston side of the slave actuator to the rod end of the additional actuator. As those skilled in the art will understand, any number of actuators can be arranged in this way so that multiple actuators can be synchronized in both closed and open positions.

[0061] Furthermore, according to one embodiment, the working tool includes at least one additional actuator and a pressure relief valve, and the hydraulic system may include an additional pressure relief valve arranged in a manner similar to the third and fourth pressure relief valves, so that the multiple actuators can be synchronized in both the extended and retracted positions as previously described.

[0062] The third and fourth pressure relief valves can also be one-way.

[0063] Furthermore, a feature found in the pressure relief valves disclosed herein is that the opening pressure depends on the back pressure (system pressure) at or within the outlet port. That is, the pressure required to open the pressure relief valve equals the set pressure (e.g., the pressure set on the spring in the corresponding first, second, third, or fourth pressure relief valve) plus the current pressure in the system at the output or outlet port of the corresponding pressure relief valve. This is also clearly visible in the accompanying drawings. However, it should be noted that this function or configuration is not absolutely necessary.

[0064] Other objects and advantages of the present invention will now be discussed through exemplary embodiments. Attached Figure Description

[0065] The invention will now be described in more detail by way of exemplary embodiments and with reference to the accompanying drawings, wherein: Figure 1 The working tool in the form of a gripper system is shown in perspective view; Figure 2 Shown in top view Figure 1 Working tools; Figure 3a It shows that according to Figure 1 and Figure 2 The working tool, wherein the main actuator and the slave actuator are in the fully extended state, and the gripper component is in the closed position; Figure 3b The work tool is shown with the main actuator and the slave actuator in the fully retracted position and the gripper component in the open position; Figure 4a A working tool is shown, wherein the master and slave actuators are in the extended state, and wherein the slave actuator is not synchronized with the master actuator in the closed position; Figure 4b A working tool is shown, wherein the master actuator and the slave actuator are in the retracted state, and wherein in the open position, the slave actuator is not synchronized with the master actuator; Figure 5a A hydraulic device according to an embodiment is schematically shown, wherein the master actuator and the slave actuator are in an extended state in the closed position, and wherein in the closed position, the slave actuator is not synchronized with the master actuator; Figure 5b It schematically shows the following based on Figure 5a The hydraulic device, wherein the main actuator and the driven actuator are in the extended state in the closed position, and in the closed position, the main actuator is not synchronized with the driven cylinder; Figure 6aA hydraulic device according to another embodiment is schematically shown, wherein the hydraulic device includes a third pressure relief valve and a fourth pressure relief valve, and wherein the main actuator and the slave actuator are in an extended state in the closed position, and wherein in the closed position, the slave actuator is not synchronized with the main actuator; Figure 6b It schematically shows the following based on Figure 6a A hydraulic device in which the main actuator and the driven actuator are extended in the closed position, and in the closed position, the main actuator is not synchronized with the driven cylinder; Figure 6c schematically shown Figure 6a and Figure 6b A hydraulic device wherein the master actuator and the slave actuator are in the retracted state in the open position, and wherein in the open position, the master actuator is not synchronized with the slave actuator; and Figure 6d schematically shown Figures 6a to 6c A hydraulic device in which the master actuator and the slave actuator are in the retracted state in the open position, and wherein in the open position, the slave actuator is not synchronized with the master actuator. Detailed Implementation

[0066] Below, we will refer to Figure 1 and Figure 2 The present invention will now be described. Figure 1 and Figure 2 An embodiment of the present invention is shown, wherein, Figure 1 One embodiment is shown in which the working tool 1 is used as a working tool in the form of a gripper system 1. In other embodiments not shown, the working tool may be a clamp, pliers, grippers, clamshell grab, bucket grab, log grab, stone grab, or waste grab.

[0067] Figure 1 The gripper system 1 is shown in perspective view. Figure 2 A top view of the gripper system 1 is shown. In the illustrated embodiment, the gripper system 1 includes a frame 6, a first gripper component 2, and a second gripper component 4. In the illustrated embodiment, the first gripper component 2 is a first gripping arm 2, and the second gripper component 4 is a second gripping arm 4. The first gripping arm 2 and the second gripping arm 4 are pivotally connected to the frame 6. A master actuator 10 is connected to the frame 6 and the first gripping arm 2 for pivoting the first gripping arm 2 from an open position 36 to a closed position 38 and from a closed position to an open position. A slave actuator 12 is connected to the frame 6 and the second gripping arm 4 for pivoting the second gripping arm 4 from an open position 36 to a closed position 38 and from a closed position to an open position.

[0068] Figure 3aThe gripper system 1 is shown from a top-down view, with the main actuator 10 and the slave actuator 12 in the fully extended state and in the closed position 38. Figure 3b The gripper system 1 is shown from a top-down view, with the main actuator 10 and the slave actuator 12 in a fully retracted state and in the open position 36.

[0069] Previously, the master actuator chamber and the slave actuator chamber were of the same size, resulting in a smaller volume of fluid released from the rod end chamber of the master actuator with each piston rod movement compared to the volume of pressurized fluid guided to its head end chamber. Consequently, the master actuator extended further and faster than its driven counterpart.

[0070] In a preferred embodiment, the master actuator 10 is proportionally larger than the slave actuator 12, enabling the master actuator 10 and the slave actuator 12 to extend synchronously. This fixed ratio can be expressed as a function of the master actuator chamber diameter X, the master actuator piston diameter Y, and the slave actuator chamber diameter Z. Therefore, this fixed ratio can be expressed as Z = (X... 2 - Y 2 ) 0.5 ·(1±K), where K is a fixed number between 0 and 0.02, preferably between 0 and 0.015, or more preferably between 0 and 0.01.

[0071] Workpieces designed to grip or grasp materials or objects may occasionally experience synchronization failures due to other factors. These may include, for example: wear; hydraulic problems; sensor malfunctions; software or control problems; electrical problems, such as wiring faults; external factors, such as one gripping component encountering greater resistance than another; calibration problems or lack of regular maintenance; and extreme temperatures that affect the performance of hydraulic fluids.

[0072] When a synchronization failure occurs, the gripping system 1 needs to balance the pressure in the master actuator 10 and the slave actuator 12. This invention enables the gripping system 1 to: Figure 4a As shown, synchronize the two gripping components 2 and 4 in the closed position; or as shown... Figure 4b As shown, the two gripping components 2 and 4 are synchronized in the open position. In one embodiment, the proposed invention, by utilizing an additional pressure relief valve, enables the two gripping components 2 and 4 to be synchronized in both the closed position 38 and the open position 36.

[0073] Figure 5aAn embodiment of the hydraulic device is schematically illustrated in the following scenario: in which the master actuator 10 and the slave actuator 12 are in an extended state in a closed position 38, and wherein, in the closed position 38, the slave actuator 12 is not synchronized with the master actuator 10. The master actuator 10, coupled to the first gripping member 2, has a first master port 40 located on the piston side and a second master port 42 located on the rod side. The slave actuator 12, coupled to the second gripping member 4, has a first slave port 44 located on the piston side and a second slave port 46 located on the rod side. The hydraulic device 8 includes a first side portion 28 and a second side portion 30, in Figure 5a In the illustrated scenario, the first side 28 is connected to the hydraulic fluid pump, and the second side 30 is connected to the hydraulic fluid tank, thus the master actuator 10 and the slave actuator 12 move toward the closed position 38. In the scenario where the gripper moves toward the open position 36, the connection is reversed, meaning that the first side 28 is connected to the hydraulic tank, and the second side 30 is connected to the hydraulic pump. Hydraulic fluid moves through the hydraulic unit 8 via hydraulic lines 26 that interconnect various components in the system. The hydraulic unit 8 also includes a first pressure relief valve 18 having a first relief pressure (p1) and a second pressure relief valve 20 having a second relief pressure (p2). The pressure relief valves 18 and 19 can be any device or mechanism capable of automatically opening to release excess pressure when the pressure exceeds a predetermined set point. In a preferred embodiment, the first relief pressure (p1) is less than the second relief pressure (p2). The master actuator 10 and the first pressure relief valve 18 are connected in parallel via the hydraulic unit 8. Similarly, the slave actuator 12 and the second pressure relief valve 20 are connected in parallel via the hydraulic unit 8. The master actuator 10 and the first pressure relief valve 18 are connected in series with the slave actuator 12 and the second pressure relief valve 20. In the illustrated embodiment, the first pressure relief valve 18 and the second pressure relief valve 20 are arranged to open in the direction from the first side 28 to the second side 30 when a first pressure (p1) or a second pressure (p2) is reached, so that the first gripper component 2 or the second gripper component 4 can move synchronously to the closed position 38. In another embodiment, not shown, the pressure relief valves 18 and 19 can be arranged to open in the opposite direction, i.e., from the second side 30 to the first side 30, which would allow the gripper components 2 and 4 to move synchronously to the open position 36.

[0074] exist Figure 5aIn this configuration, the master actuator 10 and slave actuator 12 are in the extended state at the closed position 38, and the slave actuator 12 is not synchronized with the master actuator 10. The dashed lines with arrows indicate conduits through which hydraulic fluid moves to synchronize actuators 10 and 12. As seen along the dashed lines, hydraulic fluid flows from the first side 28—in this case, the pump side—through the first pressure relief valve 18, which opens because, with the master actuator 10 fully extended, hydraulic fluid can no longer be pumped into it via the first master port 40. The hydraulic fluid then moves toward the first slave port 44 to extend the slave actuator 12, as indicated by the arrow directly above the piston on the slave actuator 12. Finally, the hydraulic fluid flows toward the second slave port 46 to the second side 30 connected to the hydraulic fluid tank.

[0075] Figure 5b It shows the relationship with Figure 5a The same hydraulic device 8 is illustrated, but instead, it shows how the hydraulic fluid moves in a scenario where the master actuator 10 is not synchronized with the slave actuator 12. As can be seen along the dashed lines, hydraulic fluid flows from the first side 28 into the master actuator 10 via the first master port 40, and flows from the second master port 42 to the second pressure relief valve 20. At this point, the second pressure relief valve 20 opens because, since the slave actuator 12 is fully extended, hydraulic fluid can no longer be pumped into the slave actuator 12 via the first slave port 44. The fluid then flows from the second pressure relief valve 20 to the second side 30 connected to the hydraulic fluid tank.

[0076] In such Figure 5a and Figure 5b In a preferred embodiment shown, the main actuator 10 and the first pressure relief valve 18 are connected in series with the first side 28; and the actuator 12 and the second pressure relief valve 20 are connected in series with the second side 30.

[0077] Figure 6a A hydraulic device 8' is schematically illustrated, comprising a third pressure relief valve 22 and a fourth pressure relief valve 24. The third pressure relief valve 22 has a third pressure relief (p3), and the fourth pressure relief valve 24 has a fourth pressure relief (p4). In a preferred embodiment, the third pressure relief (p3) is less than the first pressure relief (p1). In the illustrated embodiment, the third pressure relief valve 22 is connected in parallel with the main actuator 10 and the first pressure relief valve 18. Similarly, the fourth pressure relief valve 24 is connected in parallel with the slave actuator 12 and the second pressure relief valve 20. In the illustrated embodiment, the third pressure relief valve 22 and the fourth pressure relief valve 24 are designed to open in a direction from the second side 30 to the first side 28, and the first pressure relief valve 18 and the second pressure relief valve 20 are designed to open in a direction from the first side 28 to the second side 30.

[0078] In the proposed hydraulic device 8', the third pressure relief valve 22 and the fourth pressure relief valve 24 enable the gripping components 2 and 4 to be synchronized in both the open position 36 and the closed position 36. Figure 6a and Figure 6b The diagram illustrates how hydraulic fluid moves in a scenario where the main actuator 10 and the actuator 12 extend asynchronously. Specifically, Figure 6a This shows that the actuator 12 is out of sync. Figure 6b The main actuator 10 is out of sync. Figure 6c and Figure 6d The diagram illustrates how hydraulic fluid moves in a scenario where the master actuator 10 and slave actuator 12 are retracted and out of sync. Figure 6c This indicates that the main actuator 10 is out of sync. Figure 6d This shows that the actuator 12 is out of sync.

[0079] exist Figure 6a The illustrated embodiment depicts a scenario where the master actuator 10 and slave actuator 12 are extended in the closed position 38, and the slave actuator 12 is not synchronized with the master actuator 10. The dashed lines with arrows represent conduits through which hydraulic fluid moves to synchronize actuators 10 and 12. As seen along the dashed lines, hydraulic fluid flows from the first side 28—in this case, the pump side—through the first pressure relief valve, which opens because, with the master actuator fully extended, hydraulic fluid can no longer be pumped into the master actuator 10 via the first master port 40. The hydraulic fluid then flows toward the first slave port 44 to extend the slave actuator 12, as illustrated by the arrow directly above the piston on the slave actuator 12. Finally, the hydraulic fluid flows toward the second slave port 46 to the second side 30 connected to the hydraulic fluid tank.

[0080] Figure 6b It shows the relationship with Figure 6a The same hydraulic device 8' is illustrated, but instead, it shows how the hydraulic fluid moves in a scenario where the master actuator 10 is not synchronized with the slave actuator 12. As can be seen along the dashed lines, hydraulic fluid flows from the first side 28 into the master actuator 10 via the first master port 40, and flows from the second master port 42 to the second pressure relief valve 20. The second pressure relief valve 20 opens at this point because, since the slave actuator 12 is fully extended, hydraulic fluid can no longer be pumped into the slave actuator 12 via the first slave port 44. The fluid then moves from the second pressure relief valve 20 to the second side 30 connected to the hydraulic fluid tank.

[0081] Figure 6c and Figure 6d It shows the relationship with Figure 6a and Figure 6b The same hydraulic device 8' is shown, but a scenario is shown where the main actuator 10 and the slave actuator 12 are retracted.

[0082] Figure 6c A hydraulic device 8' is schematically shown, comprising a third relief valve 22 and a fourth relief valve 24, wherein the master actuator 10 and the slave actuator 12 are retracted in the open position 36, and in the open position 36, the master actuator 10 is not synchronized with the slave actuator 12. As can be seen along the dashed lines, hydraulic fluid flows from the second side 30—now the pump side—through the fourth relief valve 24, which is now open because, since the slave actuator 12 is retracted, hydraulic fluid can no longer be pumped into the slave actuator 12 via the second slave port 46. The fluid then flows toward the second master port 42 to retract the master actuator 10, and then flows from the first master port 40 to the first side 28 connected to the hydraulic fluid tank.

[0083] Figure 6d It schematically shows the relationship with Figure 6c The same hydraulic device 8' is shown, but in the open position 36, a scenario is shown where the slave actuator 10 is not synchronized with the master actuator 10. As can be seen along the dashed lines, hydraulic fluid flows from the second side 30—now the pump side—to the second slave port 46 to retract the slave actuator 12. Hydraulic fluid then flows from the first slave port 44 via the third relief valve 22 (which is now open because, since the master actuator is fully retracted, hydraulic fluid can no longer be pumped into the master actuator 10 via the second master port 42) to the first side 28 connected to the hydraulic fluid tank.

[0084] In a preferred embodiment, such as Figure 6a , Figure 6b , Figure 6c and Figure 6d As shown, the main actuator 10, the first pressure relief valve 18, and the third pressure relief valve 22 are connected in series with the first side 28. The secondary actuator 12, the second pressure relief valve 20, and the fourth pressure relief valve 24 are connected in series with the second side 30.

[0085] It should be understood that the present invention is not limited to the exemplary embodiments described and illustrated therein, and modifications may be made within the scope of the invention as defined in the appended claims. Furthermore, it should be understood that the aspects of the invention described herein may be combined with or independent of each other.

Claims

1. A working tool (1) designed for gripping materials or objects, the working tool (1) comprising a frame (6), a first gripper component (2) and a second gripper component (4), a main actuator (10) and a slave actuator (12), and a hydraulic device (8, 8'), the main actuator (10) having a first main port (40) on the piston side and a second main port (42) on the rod side, the slave actuator (12) having a first slave port (44) on the piston side and a second slave port (46) on the rod side. The first gripper component (2) is pivotally connected to the frame (6), the second gripper component (4) is pivotally connected to the frame (6), the main actuator (10) is connected to the frame (6) and the first gripper component (2) for pivoting the first gripper component (2) from the open position (36) to the closed position (38) and from the closed position to the open position, and the slave actuator (12) is connected to the frame (6) and the second gripper component (4). The hydraulic device (8, 8') includes a first side (28), a second side (30), and a hydraulic line (26) for pivoting the second gripper component (4) from the open position (36) to the closed position (38) and from the closed position to the open position. The hydraulic device (8, 8') includes a first side (28), a second side (30), and a hydraulic line (26) for interconnecting the first side (28) with the first main port (40) and the second main port (42), the first slave port (44) and the second slave port (46), and the second side (30). The working tool is characterized in that the hydraulic device (8, 8') further includes a first pressure relief valve (18) having a first pressure relief pressure (p1) and a second pressure relief valve (20) having a second pressure relief pressure (p2), the main actuator (10) is connected in parallel with the first pressure relief valve (18), the driven actuator (12) is connected in parallel with the second pressure relief valve (20), and the main actuator (10) and the first pressure relief valve (18) are connected in series with the driven actuator (12) and the second pressure relief valve (20), wherein, The first pressure relief valve (18) and the second pressure relief valve (20) are arranged to open in the same direction from the first side (28) to the second side (30) or from the second side (30) to the first side (28).

2. The working tool (1) according to claim 1, wherein, The first pressure relief valve (18) and the second pressure relief valve (20) are arranged to open in the direction from the first side (28) to the second side (30) when the first pressure (p1) or the second pressure (p2) is reached, so that the first gripper component (2) or the second gripper component (4) can move synchronously to the closed position (38).

3. The working tool (1) according to claim 1, wherein, The first pressure relief valve (18) and the second pressure relief valve (20) are arranged to open in the direction from the second side (30) to the first side (28) when the second pressure (p2) or the first pressure (p1) is reached, so that the first gripper component (2) or the second gripper component (4) can move synchronously to the open position (36).

4. The working tool (1) according to any one of claims 1 to 3, wherein, The first side (28) can be connected to a hydraulic fluid tank or a hydraulic fluid pump, and wherein if the first side (28) is connected to the hydraulic fluid tank, the second side (30) can be connected to the hydraulic fluid pump, or if the first side (28) is connected to the hydraulic fluid pump, the second side (30) can be connected to the hydraulic fluid tank.

5. The working tool (1) according to any one of claims 1 to 4, wherein, The main actuator (10) and the first pressure relief valve (18) are connected in series with the first side (28), and the slave actuator (12) and the second pressure relief valve (20) are connected in series with the second side (30).

6. The working tool (1) according to any one of claims 1 to 5, wherein, The master actuator (10) and the slave actuator (12) are in the extended state in the closed position (38), and wherein, if in the closed position (38), the slave actuator (12) is not synchronized with the master actuator (10), hydraulic fluid flows from the first side (28), in this case the pump side, via the first pressure relief valve (18) to the first slave port (44) to extend the slave actuator (12), and then flows from the second slave port (46) to the second side (30), the second side (30) being connected to the hydraulic fluid tank, in which case the first pressure relief valve (18) is open because, due to the extension of the master actuator (10), hydraulic fluid can no longer be pumped into the master actuator (10) via the first master port (40).

7. The working tool (1) according to any one of claims 1 to 5, wherein, The master actuator (10) and the slave actuator (12) are in the extended state in the closed position (38), and wherein, if in the closed position (38), the master actuator (10) is not synchronized with the slave cylinder (12), hydraulic fluid flows from the first side (28) into the master actuator (10) via the first master port (40), and flows from the second master port (42) to the second pressure relief valve (20), in which case the second pressure relief valve (20) opens because, due to the extension of the slave actuator (12), hydraulic fluid can no longer be pumped into the slave actuator (12) via the first slave port (44), and then flows from the second pressure relief valve (20) to the second side (30), the second side (30) being connected to the hydraulic fluid tank.

8. The working tool (1) according to any one of the preceding claims, wherein, The first venting pressure (p1) is less than the second venting pressure (p2).

9. The working tool (1) according to any one of the preceding claims, wherein, The hydraulic device (8, 8') further includes a third pressure relief valve (22) having a third pressure relief (p3) and a fourth pressure relief valve (24) having a fourth pressure relief (p4), the third pressure relief valve (22) being connected in parallel with the main actuator (10) and the first pressure relief valve (18), and the fourth pressure relief valve (24) being connected in parallel with the slave actuator (12) and the second pressure relief valve (20), wherein the third pressure relief valve (22) and the fourth pressure relief valve (24) are designed to open in the direction from the second side (30) to the first side (28), and wherein the first pressure relief valve (18) and the second pressure relief valve (20) are designed to open in the direction from the first side (28) to the second side (30).

10. The working tool (1) according to claim 9, wherein, The main actuator (1), the first pressure relief valve (18) and the third pressure relief valve (22) are connected in series with the first side (28), and the slave actuator (12), the second pressure relief valve (20) and the fourth pressure relief valve (24) are connected in series with the second side (30).

11. The working tool (1) according to claim 9 or 10, wherein, The master actuator (10) and the slave actuator (12) are in the retracted state in the open position (36), and wherein, if in the open position (36), the master actuator (10) is not synchronized with the slave actuator (12), hydraulic fluid flows from the second side (30), which is the pump side, via the fourth pressure relief valve (24) to the second master port (42) to retract the master actuator (10), and then flows from the first master port (40) to the first side (28), which is connected to the hydraulic fluid tank, in which case the fourth pressure relief valve (24) is open because, due to the retraction of the slave actuator (12), hydraulic fluid can no longer be pumped into the slave actuator (12) via the second slave port (46).

12. The working tool (1) according to claims 9 to 10, wherein, The master actuator (10) and the slave actuator (12) are in the retracted state in the open position (36), and wherein, if in the open position (36), the slave actuator (12) is not synchronized with the master actuator (10), hydraulic fluid flows from the second side (30), which is the pump side, to the second slave port (46) to retract the slave actuator (12), and then from the first slave port (44) via the third pressure relief valve (22) to the first side (28), which is connected to the hydraulic fluid tank, in which case the third pressure relief valve (22) is open because, due to the retraction of the master actuator (10), hydraulic fluid can no longer be pumped into the master actuator (10) via the second master port (42).

13. The working tool (1) according to any one of claims 9 to 12, wherein, The third venting pressure (p3) is less than the first venting pressure (p1), and wherein the third venting pressure (p3) is less than the second venting pressure (p2).

14. The working tool (1) according to any one of the preceding claims, wherein, The first gripper component (2) is a first gripper arm (2), and the second gripper component (4) is a second gripper arm (4).

15. The working tool (1) according to any one of claims 1 to 14, wherein, Any one of the first pressure relief valve (18), the second pressure relief valve (20), the third pressure relief valve (22), or the fourth pressure relief valve (24) is unidirectional or of the backflow type.

16. A quick-connect unit or tilting rotator, comprising the working tool (1) according to any one of claims 1 to 15.

Images