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CN-121986203-A - Gripper system with hydraulic device

CN121986203ACN 121986203 ACN121986203 ACN 121986203ACN-121986203-A

Abstract

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

Inventors

  • Christian Schelling

Assignees

  • 奥伊奎克有限公司

Dates

Publication Date
20260505
Application Date
20240910
Priority Date
20230920

Claims (16)

  1. 1. A work tool (1) for a machine designed to grip a material or an object, the work tool (1) comprising a frame (6), a first gripper part (2) and a second gripper part (4), a master actuator (10) and a slave actuator (12), and hydraulic means (8, 8'), the master actuator (10) having a first master port (40) on the piston side and a second master 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 part (2) being pivotably coupled to the frame (6), the second gripper part (4) being pivotably coupled to the frame (6), the master actuator (10) being coupled to the frame (6) and the first gripper part (2) for pivoting the first gripper part (2) from an open position (36) to a closed position and the second gripper part (4) from the closed position to the closed position (38), for pivoting the second gripper part (4) from an open position (36) to a closed position (38) and from the closed position to the open position, the hydraulic device (8, 8 ') comprising a first side (28), a second side (30) and a hydraulic line (26) for coupling the first side (28) in parallel with the first and second main ports (40, 42), the first and second slave ports (44, 46) and the second side (30), the working implement being characterized in that the hydraulic device (8, 8') further comprises a first relief valve (18) with a first pressure (p 1) and a second relief valve (20) with a second relief pressure (p 2), the master actuator (10) being coupled in parallel with the first relief valve (18), the slave actuator (12) being coupled in parallel with the second relief valve (20), and the master actuator (10) and the second relief valve (20) being coupled in series with the first relief valve (12) and the second relief valve (20), the first relief valve (18) and the second 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. 2. Work implement (1) according to claim 1, wherein the first relief valve (18) and the second relief valve (20) are arranged to open in a direction from the first side (28) to the second side (30) upon reaching the first pressure (p 1) or the second pressure (p 2), such that the first gripper part (2) or the second gripper part (4) can be moved synchronously to a closed position (38).
  3. 3. Work implement (1) according to claim 1, wherein the first relief valve (18) and the second relief valve (20) are arranged to open in a direction from the second side (30) to the first side (28) upon reaching the second pressure (p 2) or the first pressure (p 1), such that the first gripper part (2) or the second gripper part (4) can be moved synchronously to an open position (36).
  4. 4. A work tool (1) according to any one of claims 1-3, wherein the first side (28) is connectable to a hydraulic fluid tank or a hydraulic fluid pump, and wherein the second side (30) is connectable to the hydraulic fluid pump if the first side (28) is connected to the hydraulic fluid tank or the second side (30) is connectable to the hydraulic fluid tank if the first side (28) is connected to the hydraulic fluid pump.
  5. 5. The work implement (1) according to any one of claims 1 to 4, wherein the master actuator (10) and the first relief valve (18) are coupled in series with the first side (28) and the slave actuator (12) and the second relief valve (20) are coupled in series with the second side (30).
  6. 6. Work implement (1) according to any one of claims 1 to 5, wherein the master actuator (10) and the slave actuator (12) are in an 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 is from the first side (28), in this case the pump side, flows via the first relief valve (18) to the first slave port (44) to extend the slave actuator (12) and then from the second slave port (46) to the second side (30), the second side (30) being connected to the hydraulic fluid tank, the first relief valve (18) being opened in this case because hydraulic fluid cannot be pumped into the master actuator (10) via the first master port (40) any more due to the extension of the master actuator (10).
  7. 7. Work implement (1) according to any one of claims 1 to 5, wherein the master actuator (10) and the slave actuator (12) are in an 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 from the second master port (42) to the second relief valve (20), in which case the second relief valve (20) is opened, because hydraulic fluid cannot be pumped into the slave actuator (12) via the first slave port (44) anymore due to the slave actuator (12) extending, and then flows from the second valve (20) to the second side (30), the second side (30) being connected to the hydraulic fluid tank.
  8. 8. Work implement (1) according to any of the preceding claims, wherein the first relief pressure (p 1) is smaller than the second relief pressure (p 2).
  9. 9. Work implement (1) according to any of the preceding claims, wherein the hydraulic device (8, 8') further comprises a third relief valve (22) with a third relief pressure (p 3) and a fourth relief valve (24) with a fourth relief pressure (p 4), the third relief valve (22) being coupled in parallel with the main actuator (10) and the first relief valve (18), and the fourth relief valve (24) being coupled in parallel with the slave actuator (12) and the second relief valve (20), and wherein the third relief valve (22) and the fourth relief valve (24) are designed to open in a direction from the second side (30) to the first side (28), and wherein the first relief valve (18) and the second relief valve (20) are designed to open in a direction from the first side (28) to the second side (30).
  10. 10. The work tool (1) according to claim 9, wherein the master actuator (1), the first relief valve (18) and the third relief valve (22) are coupled in series with the first side (28), and wherein the slave actuator (12), the second relief valve (20) and the fourth relief valve (24) are coupled in series with the second side (30).
  11. 11. Work implement (1) according to claim 9 or 10, wherein the master actuator (10) and the slave actuator (12) are in a 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 is from the second side (30), in which case the second side (30) is the pump side, flows via the fourth 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), the first side (28) being connected to the hydraulic fluid tank, in which case the fourth relief valve (24) is open, because hydraulic fluid cannot be pumped into the slave actuator (12) via the second slave port (46) due to the slave actuator (12) retracting.
  12. 12. Work implement (1) according to claims 9-10, wherein the master actuator (10) and the slave actuator (12) are in a 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), in which case the second side (30) is the pump side, to the second slave port (46) to retract the slave actuator (12) and then from the first slave port (44) to the first side (28) via the third relief valve (22), the first side (28) being connected to the hydraulic fluid tank, in which case the third relief valve (22) is open, because hydraulic fluid cannot be pumped into the master actuator (10) via the second master port (42) due to retraction of the master actuator (10).
  13. 13. The work implement (1) according to any one of claims 9 to 12, wherein the third relief pressure (p 3) is smaller than the first relief pressure (p 1), and wherein the third relief pressure (p 3) is smaller than the second relief pressure (p 2).
  14. 14. Work implement (1) according to any of the preceding claims, wherein the first gripper component (2) is a first gripping arm (2), and wherein the second gripper component (4) is a second gripping arm (4).
  15. 15. The work tool (1) according to any one of the preceding claims 1 to 14, wherein any one of the first relief valve (18), the second relief valve (20), the third relief valve (22) or the fourth relief valve (24) is of the one-way or of the check type.
  16. 16. A quick coupling unit or tilt rotator comprising a work tool (1) according to any of the preceding claims 1-15.

Description

Gripper system with hydraulic device Technical Field The present invention relates to the field of gripper or jaw systems for use on construction or forestry machines and/or in combination with quick couplers, tool holders or tilting rotators coupled to such machines, and in particular to a hydraulic system associated with such gripper or jaw systems. Background Generally, when gripper systems for machinery are used, whether they are used for gripping gravel via a bucket, for gripping logs (logging), or for gripping various elements during construction, two hydraulic cylinders are involved to close and open the grippers. In the prior art, the two hydraulic cylinders are controlled and coupled in a side-by-side manner, with different solutions to synchronize the cylinders, since a pair of grippers is required to move synchronously. Typically, such parallel coupled hydraulic cylinders are of the same size. One problem that commonly arises with gripper systems according to the prior art is synchronization problems due to uneven resistance or load on one of a pair of grippers or jaws. In the field of grippers, jaw systems, forestry machines or clamshell type grippers, the unsynchronized movement of the two gripper components is particularly troublesome due to the precision required for gripping the material or object. In order to solve the synchronization problem in the hydraulic actuator, different solutions are used, which are however independent of the gripper system. US 5682955A discloses a blade control system including a directional control valve, a fluid regeneration valve, and a selector valve for selectively controlling fluid flow between the pump and first and second hydraulic cylinders and between the cylinders. By positioning the valves in preselected operating positions, pressurized fluid from the pump is directed to the head-end chamber of the first cylinder, fluid discharged from the rod-end chamber of the first cylinder is diverted to the head-end chamber of the second cylinder, and fluid discharged from the rod-end chamber of the second cylinder is combined with fluid directed to the head-end chamber of the first cylinder to provide two-stage fluid regeneration to increase the extension speed of the cylinders. However, US 5682955A does not discuss synchronization problems associated with gripper systems, jaw systems, work tools, and the like. Another example is provided in US 5110251A, which discloses a hydraulic platform lift for use on trucks and truck trailers having two hydraulic cylinders, one on each side of the door. These cylinders are phasing cylinders, one of which is larger than the other by a specific proportion. The cross-sectional area of the fluid in the rod end of the large cylinder minus the area of the rod is equal to the cross-sectional area of the small cylinder. A connecting line interconnects the rod end of the large cylinder with the cap end of the small cylinder. Hydraulic fluid can be directed by the controller into the cap end of the large cylinder or the cap end of the small cylinder. For upward movement, hydraulic fluid is forced into the rod end of the small cylinder. This in turn forces hydraulic fluid through the connecting lines into the rod ends of the cylinders, lifting both pistons. For downward movement, hydraulic fluid is forced into the cap end of the large cylinder, forcing fluid out of the rod end of the large cylinder and into the cap end of the small cylinder. This causes the two cylinders to move downward. The platform lift also has a self-leveling feature to enable the pistons to be flush with one another by moving the platform to an uppermost position. The operating mechanism is located entirely on the side of the trailer. The platform can be caused to exert a positive upward force or a positive downward force during use. However, US 5110251A also does not discuss any synchronization problems associated with the gripper system or the work implement. Disclosure of Invention The present invention is directed to improving the efficiency of supplying hydraulic fluid to a work implement that includes two hydraulic actuators arranged in a master/slave serial flow relationship. More specifically, the present invention aims to allow a synchronous movement between a master and a slave actuator controlling a gripping member in a work implement of a machine. Another object of the present invention is to provide a hydraulic device that enables the synchronization of the master-slave actuator in either the extended position or the retracted position, or both. These and other objects are achieved by the invention as defined in the independent claims. Preferred embodiments are defined by the dependent claims. The inventors of the present invention have found that by coupling a first actuator, e.g. a hydraulic cylinder, and a second actuator, e.g. a hydraulic cylinder, in series, and by compensating the volumes in the first actuator and the second actuator, respecti