A double-arm grasping mechanism with fixed-length locking function

Abstract

The present invention provides a dual-arm grabbing mechanism with a fixed-length locking function, belonging to the field of mechanical design. The mechanism comprises a hollow piston rod hydraulic cylinder, a connecting oil circuit, a right-arm movable pulley trolley, a single-acting hydraulic cylinder, a chain pulley transmission mechanism, a left-arm movable pulley trolley, a bidirectional single-rod hydraulic cylinder assembly, a guide device, a fixed-length rod, a left grabbing mechanical arm, a right grabbing mechanical arm, and a housing. The housing is internally provided with the hollow piston rod hydraulic cylinder, a connecting oil circuit, a right-arm movable pulley trolley, a single-acting hydraulic cylinder, a chain pulley transmission mechanism, a left-arm movable pulley trolley, a bidirectional single-rod hydraulic cylinder assembly, a guide device, and a fixed-length rod. The upper portions of the left and right grabbing mechanical arms are disposed within the housing, while the lower portions of the left and right grabbing mechanical arms extend out of the housing. The present invention implements the fixed-length locking function of the dual-arm grabbing mechanism through the fixed-length rod mechanical locking mechanism and its principle, thereby improving the reliability and safety of the device.

Description

Technical Field

[0001] The present invention relates to the field of mechanical design, and in particular to a double-arm grasping mechanism with a fixed-length locking function. Background Art

[0002] Today, engineering robots are widely used in various fields. To ensure the safety and normal use of such equipment, many devices are equipped with corresponding locking functions. The locking function refers to the limiting function of the locking device on the actuator in the system. The locking device must not only keep the mechanism locked in a certain position, but also ensure that it has reliable strength and rigidity. During engineering use, it is usually required that the locking device can stably withstand external loads for a long time without any displacement when the movement stops, that is, it is required to have a locking and positioning function and no "soft leg" phenomenon. In some special fields, such as aviation and military fields, the position accuracy of the actuator is high when working, and it is required that it has no displacement changes for a long time under load, and more reliable safety is also required.

[0003] Hydraulic cylinders in general engineering hydraulic systems maintain their position and withstand a certain load using a hydraulic locking circuit. However, if the hydraulic piping is damaged, the locking mechanism will fail, and internal leakage of the hydraulic valve is inevitable. This places higher demands on the corresponding locking device.

[0004] Therefore, under long-term load conditions, the existing hydraulic locking circuit has the defect of inevitable leakage in the hydraulic valve, which causes the piston to slip, the locking to fail, and the system to be unstable. Summary of the Invention

[0005] The present invention aims to provide a dual-arm grabbing mechanism with a fixed-length locking function. This mechanism utilizes a fixed-length rod mechanical locking mechanism and principle to achieve this fixed-length locking function for dual-arm grabbing. The locking device provides reliable mechanical locking of the grabbing mechanism, improving the reliability and safety of the device and resolving the safety hazard associated with leakage from the hydraulic valve in the existing hydraulic locking circuit.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A double-arm grasping mechanism with a fixed-length locking function, characterized in that:

[0008] It includes a hollow piston rod hydraulic cylinder, a connecting oil circuit, a right arm movable pulley trolley, a single-acting hydraulic cylinder, a first chain pulley transmission mechanism, a left arm movable pulley trolley, a two-way single-rod hydraulic cylinder group, a guide device, a fixed-length rod, a left grabbing mechanical arm, a right grabbing mechanical arm, a body shell and a second chain pulley transmission mechanism. The body shell is internally provided with a hollow piston rod hydraulic cylinder, a connecting oil circuit, a right arm movable pulley trolley, a single-acting hydraulic cylinder, a first chain pulley transmission mechanism, a left arm movable pulley trolley, a two-way single-rod hydraulic cylinder group, a guide device, a fixed-length rod and a second chain pulley transmission mechanism. The upper parts of the left grabbing mechanical arm and the right grabbing mechanical arm are arranged inside the body shell, and the lower parts of the left grabbing mechanical arm and the right grabbing mechanical arm extend out of the body shell.

[0009] The hollow piston rod hydraulic cylinder and the two-way single-rod hydraulic cylinder group are connected in parallel, and the hollow piston rod hydraulic cylinder and the two-way single-rod hydraulic cylinder group are both connected to one side of the right arm movable pulley trolley, and the other side of the right arm movable pulley trolley is connected to the right grabbing robotic arm through a first chain pulley transmission mechanism, the fixed-length rod is arranged at the lower end of the two-way single-rod hydraulic cylinder group, and the guide device is sleeved on the outside of the fixed-length rod, and the two-way single-rod hydraulic cylinder group and the left end of the fixed-length rod are both connected to one side of the left arm movable pulley trolley, and the other side of the left arm movable pulley trolley is connected to the left grabbing robotic arm through a second chain pulley transmission mechanism.

[0010] A single-acting hydraulic cylinder serving as a hydraulic actuator is provided inside the right arm movable pulley trolley. The right arm movable pulley trolley has a hole opened in the direction of movement of the single-acting hydraulic cylinder piston. The single-acting hydraulic cylinder can be extended to the outside of the right arm movable pulley trolley when the locking head is extended. The single-acting hydraulic cylinder is connected to the hollow piston rod hydraulic cylinder through the connecting oil circuit inside the right arm movable pulley trolley. A locking groove is provided on the right end of the fixed-length rod, and the locking groove can cooperate with the locking head of the single-acting hydraulic cylinder for locking.

[0011] Furthermore, the hollow piston rod hydraulic cylinder includes a first cylinder bottom, a cylinder head, a cylinder barrel, a cylinder cover, a guide sleeve, a central oil pipe and a hollow piston rod. The first cylinder bottom is arranged on one side of the hollow piston rod hydraulic cylinder, and the cylinder head is arranged on the other side of the hollow piston rod hydraulic cylinder. The first cylinder bottom and the cylinder head are connected by several pull rods. One end of the cylinder barrel is connected to the first cylinder bottom, and the other end of the cylinder barrel is connected to the cylinder head. The hollow piston rod is arranged inside the cylinder barrel, the cylinder cover is fixed to the cylinder head by a countersunk screw, and the guide sleeve is arranged between the cylinder head and the hollow piston rod.

[0012] A first opening is provided at the center of the bottom of the first cylinder, and a second opening is provided at the center of the cylinder head. One end of the through oil pipe is connected to the first opening, and the other end of the through oil pipe is flush with the end surface of the second opening. The through oil pipe passes through the hollow piston rod along the axial center line of the hollow piston rod hydraulic cylinder and the hollow piston rod, and the aperture of the second opening is equal to the outer diameter of the hollow piston rod.

[0013] Furthermore, the hollow piston rod includes a first piston and a sealing device. The first piston is threaded or welded to one end of the hollow piston rod. The first piston is slidably arranged inside the cylinder. The first piston divides the cylinder into a first oil chamber and a second oil chamber. The sealing device is arranged at the end of the first piston.

[0014] The bottom of the first cylinder is provided with a first oil port, which connects the first oil chamber and the outside world. The end of the through oil pipe close to the bottom of the first cylinder is provided with a second oil port connected to the outside world. The through oil pipe and the internal cavity of the hollow piston rod form a through oil path structure. The cylinder head is provided with a third oil port, which connects the second oil chamber and the outside world. The other end of the hollow piston rod is provided with a fourth oil port, and the hollow piston rod is connected to one side of the right arm movable pulley trolley.

[0015] Furthermore, the bidirectional single-rod hydraulic cylinder group includes a first single-rod hydraulic cylinder and a second single-rod hydraulic cylinder which share a second cylinder bottom, and the second cylinder bottom is connected in parallel with the first cylinder bottom.

[0016] The first single-rod hydraulic cylinder includes a first piston rod and a third piston. One end of the first piston rod extends out of the first single-rod hydraulic cylinder to the outside, and the other end of the first piston rod is arranged inside the first single-rod hydraulic cylinder. The other end of the first piston rod is connected to the third piston by threaded connection or welding. The third piston divides the internal cavity of the first single-rod hydraulic cylinder into a first rod cavity and a first rodless cavity. The cylinder head of the first single-rod hydraulic cylinder is provided with a sixth oil port communicating with the first rod cavity and the outside, and one end of the bottom of the second cylinder is provided with a seventh oil port communicating with the first rodless cavity and the outside. The first piston rod is connected to one side of the left arm movable pulley trolley.

[0017] The second single-rod hydraulic cylinder includes a second piston rod and a fourth piston. One end of the second piston rod extends out of the second single-rod hydraulic cylinder to the outside, and the other end of the second piston rod is arranged inside the second single-rod hydraulic cylinder. The other end of the second piston rod is connected to the fourth piston by threaded connection or welding. The fourth piston divides the internal cavity of the second single-rod hydraulic cylinder into a second rodless cavity and a second rod cavity. The cylinder head of the second single-rod hydraulic cylinder is provided with a ninth oil port communicating with the second rod cavity and the outside. The other end of the second cylinder bottom is provided with an eighth oil port communicating with the second rodless cavity and the outside. The second piston rod is connected to one side of the right arm movable pulley trolley.

[0018] Furthermore, the base of the single-acting hydraulic cylinder is fixed in the mounting groove on the right arm movable pulley trolley by bolts, and a single output rod is installed inside the single-acting hydraulic cylinder to match it. A second piston is connected to the single output rod by threaded connection or welding, and a spring is provided on the top of the second piston, and the spring is connected to the top of the inner cavity of the single-acting hydraulic cylinder.

[0019] Furthermore, the single-acting hydraulic cylinder is provided with a fifth oil port, and the fifth oil port of the single-acting hydraulic cylinder is connected to the fourth oil port of the hollow piston rod through a connecting oil circuit.

[0020] Furthermore, a plurality of threaded holes are evenly arranged on one end of the cylinder head, one end of a plurality of tie rods is connected to the cylinder head through threads, and the other end of the plurality of tie rods is connected to the first cylinder bottom through a plurality of nuts.

[0021] Furthermore, a sealing ring is provided at the connection between the cylinder barrel and the first cylinder bottom and cylinder head, a dust ring is provided at the inner ring groove of the cylinder head and is in contact with the middle piston rod, a sealing ring is provided at the inner ring groove of the guide sleeve, a guide ring and a sealing ring are provided at the side ring groove of the first piston, and a sliding sealing ring is provided in the inner ring groove of the hollow piston rod and is in contact with the middle oil pipe.

[0022] Furthermore, connection forms of the first oil port, the second oil port, the third oil port, the fourth oil port and the fifth oil port include threaded connection, flange connection, plate connection, stacking connection and plug-in connection.

[0023] Furthermore, the outer ends of the oil ports of the first oil port, the second oil port, the third oil port, the fourth oil port and the fifth oil port are provided with hydraulic reversing valves or solenoid valves, and the first oil port, the second oil port, the third oil port, the fourth oil port and the fifth oil port can all be connected to the oil tank.

[0024] Advantages of the present invention:

[0025] 1. The present invention provides a double-arm grasping mechanism with a fixed-length locking function. The locking position of the fixed-length rod can be changed according to the size of the grasped object, so that the distance between the left and right grasping mechanical arms can remain unchanged, thereby achieving the purpose of locking the fixed-length object.

[0026] 2. The present invention forms a central oil circuit structure through the central oil pipe at the bottom of the cylinder and the cavity structure of the hollow piston rod, which realizes the function of oil passing through the piston rod, avoids the arrangement of external oil pipes and oil circuits, and does not affect the oil circuit of the hydraulic cylinder itself for realizing the telescopic function; at the same time, this central oil circuit structure solves the hydraulic pipeline design problem of a mobile carrier equipped with a hydraulic system or a hydraulic actuator under the motion condition driven by the hydraulic cylinder piston rod, and optimizes the structure of such hydraulic system; the connecting oil pipe is arranged in the mobile carrier and connected to the oil outlet of the hydraulic cylinder piston rod, serving as the connecting oil circuit with the hydraulic actuator, which also reduces the arrangement of external pipelines originally required; it can realize that the mobile carrier is connected to an external oil source when there is no oil pipe in the outside world, thereby simplifying the hydraulic system structure on the mobile carrier; reducing the quality of the hydraulic system and improving the controllability of the system.

[0027] 3. The locking function of this invention is achieved through the interaction between the groove in the fixed-length rod and the locking head of the single-acting hydraulic cylinder. A groove is provided at the right end of the fixed-length rod, with an aperture diameter identical to that of the single-acting hydraulic cylinder locking head. When the locking head is extended, it tightly engages the groove in the fixed-length rod, achieving reliable mechanical locking. Retracting the locking head unlocks the lock. This allows for quick and easy locking / unlocking. Two guides are installed on either side of the fixed-length rod, effectively enhancing the smooth operation of the transmission.

[0028] 4. The present invention optimizes the connection structure between different hydraulic cylinders. First, two single-rod hydraulic cylinders in different directions are connected in series to form a bidirectional single-rod hydraulic cylinder group, which realizes the reciprocating motion of the left and right grabbing robotic arms without increasing the length of the body structure; then the hydraulic cylinder group is connected in parallel with the hollow piston rod hydraulic cylinder to meet the different requirements of the reciprocating speed and running distance of the movable pulley trolleys on the left and right sides; the technology of oil passing through the rod is used to achieve the purpose of controlling the hydraulic actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the present invention;

[0030] Figure 2 It is a structural cross-sectional view of the present invention;

[0031] Figure 3 It is the hydraulic principle diagram of the present invention;

[0032] In the figure: 1. Hydraulic cylinder with hollow piston rod; 1-1. First cylinder bottom; 1-2. Cylinder head; 1-3. Cylinder barrel; 1-4. Cylinder cover; 1-5. Guide sleeve; 1-6. First oil port; 1-7. Second oil port; 1-8. Third oil port; 1-9. Center oil pipe; 1-10. First oil chamber; 1-11. Second oil chamber; 1-12. Hollow piston rod; 1-13. First piston; 1-14. Sealing device; 1-15. Fourth oil port.

[0033] 2. Connect the oil circuit;

[0034] 3. Right arm movable pulley trolley;

[0035] 4. Single-acting hydraulic cylinder; 4-1. Fifth oil port; 4-2. Second piston;

[0036] 5. First chain pulley transmission mechanism;

[0037] 6. Left arm movable pulley trolley;

[0038] 7. Bidirectional single-rod hydraulic cylinder assembly; 7-1. First piston rod; 7-2. Third piston; 7-3. Sixth oil port; 7-4. Seventh oil port; 7-5. First rod chamber; 7-6. First rodless chamber; 7-7. Second cylinder bottom; 7-8. Second piston rod; 7-9. Fourth piston; 7-10. Eighth oil port; 7-11. Ninth oil port; 7-12. Second rodless chamber; 7-13. Second rod chamber;

[0039] 8. Guide device;

[0040] 9. Fixed length pole;

[0041] 10. Left grabbing robotic arm;

[0042] 11. Right grabbing robot arm;

[0043] 12. Body shell;

[0044] 13. Second chain pulley transmission mechanism. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention.

[0046] like Figure 1 As shown, a double-arm grabbing mechanism with a fixed-length locking function includes a hollow piston rod hydraulic cylinder 1, a connecting oil circuit 2, a right arm movable pulley trolley 3, a single-acting hydraulic cylinder 4, a first chain pulley transmission mechanism 5, a left arm movable pulley trolley 6, a two-way single-rod hydraulic cylinder group 7, a guide device 8, a fixed-length rod 9, a left grabbing mechanical arm 10, a right grabbing mechanical arm 11, a body shell 12 and a second chain pulley transmission mechanism 13. The body shell 12 is internally provided with a hollow piston rod hydraulic cylinder 1, a connecting oil circuit 2, a right arm movable pulley trolley 3, a single-acting hydraulic cylinder 4, a first chain pulley transmission mechanism 5, a left arm movable pulley trolley 6, a two-way single-rod hydraulic cylinder group 7, a guide device 8, a fixed-length rod 9 and a second chain pulley transmission mechanism 13. The upper parts of the left grabbing mechanical arm 10 and the right grabbing mechanical arm 11 are arranged inside the body shell 12, and the lower parts of the left grabbing mechanical arm 10 and the right grabbing mechanical arm 11 extend out of the body shell 12.

[0047] The hollow piston rod hydraulic cylinder 1 and the two-way single-rod hydraulic cylinder group 7 are connected in parallel. The hollow piston rod hydraulic cylinder 1 and the two-way single-rod hydraulic cylinder group 7 are both connected to one side of the right arm movable pulley trolley 3. The other side of the right arm movable pulley trolley 3 is connected to the right grabbing mechanical arm 11 through the first chain pulley transmission mechanism 5. The fixed-length rod 9 is arranged at the lower end of the two-way single-rod hydraulic cylinder group 7. The guide device 8 is sleeved on the outside of the fixed-length rod 9. The left ends of the two-way single-rod hydraulic cylinder group 7 and the fixed-length rod 9 are both connected to one side of the left arm movable pulley trolley 6. The fixed-length rod 9 is driven by the left arm movable pulley trolley 6 and moves back and forth in the guide device 8. The other side of the left arm movable pulley trolley 6 is connected to the left grabbing mechanical arm 10 through the second chain pulley transmission mechanism 13.

[0048] The right arm movable pulley trolley 3 is internally provided with a single-acting hydraulic cylinder 4 as a hydraulic actuator. The right arm movable pulley trolley 3 has a hole facing the piston movement direction of the single-acting hydraulic cylinder 4. The single-acting hydraulic cylinder 4 can be extended outside the right arm movable pulley trolley 3 when the lock head is extended. The single-acting hydraulic cylinder 4 is connected to the hollow piston rod hydraulic cylinder 1 through the connecting oil circuit 2 inside the right arm movable pulley trolley 3. A locking groove is provided on the right end of the fixed-length rod 9. The locking groove can cooperate with the lock head of the single-acting hydraulic cylinder 4 for locking. The fixed-length rod 9 with the locking groove and the guide device 8 cooperating therewith form a moving pair.

[0049] As a preferred embodiment of the present invention, Figure 1 and Figure 2As shown, the hollow piston rod hydraulic cylinder 1 includes a first cylinder bottom 1-1, a cylinder head 1-2, a cylinder barrel 1-3, a cylinder cover 1-4, a guide sleeve 1-5, a central oil pipe 1-9 and a hollow piston rod 1-12. The first cylinder bottom 1-1 is arranged on one side of the hollow piston rod hydraulic cylinder 1, and the cylinder head 1-2 is arranged on the other side of the hollow piston rod hydraulic cylinder 1. The first cylinder bottom 1-1 and the cylinder head 1-2 are connected by a number of pull rods. One end of the cylinder barrel 1-3 is connected to the first cylinder bottom 1-1, and the other end of the cylinder barrel 1-3 is connected to the cylinder head 1-2. The hollow piston rod 1-12 is arranged inside the cylinder barrel 1-3. The cylinder cover 1-4 is fixed to the cylinder head 1-2 by a countersunk screw, and the guide sleeve 1-5 is arranged between the cylinder head 1-2 and the hollow piston rod 1-12.

[0050] A first opening is provided at the center of the first cylinder bottom 1-1, and a second opening is provided at the center of the cylinder head 1-2. One end of the through oil pipe 1-9 is connected to the first opening, and the other end of the through oil pipe 1-9 is flush with the end face of the second opening. The through oil pipe 1-9 passes through the hollow piston rod 1-12 along the axial center line of the hollow piston rod hydraulic cylinder 1 and the hollow piston rod 1-12. The aperture of the second opening is equal to the outer diameter of the hollow piston rod 1-12.

[0051] As a preferred embodiment of the present invention, the hollow piston rod 1-12 includes a first piston 1-13 and a sealing device 1-14. The first piston 1-13 is threaded or welded to one end of the hollow piston rod 1-12. The first piston 1-13 is slidably arranged inside the cylinder 1-3. The first piston 1-13 separates the cylinder 1-3 into a first oil chamber 1-10 and a second oil chamber 1-11. The sealing device 1-14 is arranged at the end of the first piston 1-13.

[0052] The first cylinder bottom 1-1 is provided with a first oil port 1-6, which connects the first oil chamber 1-10 with the outside world. The through oil pipe 1-9 is provided with a second oil port 1-7 connected to the outside world at one end close to the first cylinder bottom 1-1. The through oil pipe 1-9 and the internal cavity of the hollow piston rod 1-12 form a through oil circuit structure. The cylinder head 1-2 is provided with a third oil port 1-8, which connects the second oil chamber 1-11 with the outside world. The other end of the hollow piston rod 1-12 is provided with a fourth oil port 1-15. The hollow piston rod 1-12 is connected to one side of the right arm movable pulley trolley 3.

[0053] As a preferred embodiment of the present invention, the bidirectional single-rod hydraulic cylinder group 7 includes a first single-rod hydraulic cylinder and a second single-rod hydraulic cylinder sharing a second cylinder bottom 7-7, and the second cylinder bottom 7-7 is connected in parallel with the first cylinder bottom 1-1.

[0054] The first single-rod hydraulic cylinder includes a first piston rod 7-1 and a third piston 7-2. One end of the first piston rod 7-1 extends out of the first single-rod hydraulic cylinder to the outside, and the other end of the first piston rod 7-1 is arranged inside the first single-rod hydraulic cylinder. The other end of the first piston rod 7-1 is connected to the third piston 7-2 by threaded connection or welding. The third piston 7-2 divides the internal cavity of the first single-rod hydraulic cylinder into a first rod cavity 7-5 and a first rodless cavity 7-6. A sixth oil port 7-3 communicating with the first rod cavity 7-5 and the outside is provided on the cylinder head of the first single-rod hydraulic cylinder, and a seventh oil port 7-4 communicating with the first rodless cavity 7-6 and the outside is provided on one end of the second cylinder bottom 7-7. The first piston rod 7-1 is connected to one side of the left arm movable pulley trolley 6.

[0055] The second single-rod hydraulic cylinder includes a second piston rod 7-8 and a fourth piston 7-9. One end of the second piston rod 7-8 extends out of the second single-rod hydraulic cylinder to the outside world, and the other end of the second piston rod 7-8 is arranged inside the second single-rod hydraulic cylinder. The other end of the second piston rod 7-8 is connected to the fourth piston 7-9 by threaded connection or welding. The fourth piston 7-9 divides the internal cavity of the second single-rod hydraulic cylinder into a second rodless cavity 7-12 and a second rod cavity 7-13. The cylinder head of the second single-rod hydraulic cylinder is provided with a ninth oil port 7-11 that communicates with the second rod cavity 7-13 and the outside world. The other end of the second cylinder bottom 7-7 is provided with an eighth oil port 7-10 that communicates with the second rodless cavity 7-12 and the outside world. The second piston rod 7-8 is connected to one side of the right arm movable pulley trolley 3.

[0056] As a preferred embodiment of the present invention, the base of the single-acting hydraulic cylinder 4 is fixed in the mounting groove on the right arm movable pulley trolley 3 by bolt connection, and a single output rod matching it is installed inside the single-acting hydraulic cylinder 4, and a second piston 4-2 is connected to the single output rod by threaded connection or welding, and a spring is provided on the top of the second piston 4-2, and the spring is connected to the top of the inner cavity of the single-acting hydraulic cylinder 4.

[0057] As a preferred embodiment of the present invention, the single-acting hydraulic cylinder 4 is provided with a fifth oil port 4-1, and the fifth oil port 4-1 of the single-acting hydraulic cylinder 4 is connected to the fourth oil port 1-15 of the hollow piston rod 1-12 through the connecting oil line 2.

[0058] As a preferred embodiment of the present invention, one end of the cylinder head 1-2 is evenly provided with several threaded holes, one end of several tie rods is connected to the cylinder head 1-2 through threads, and the other end of several tie rods is connected to the first cylinder bottom 1-1 through several nuts.

[0059] As a preferred embodiment of the present invention, a sealing ring is provided at the connection between the cylinder barrel 1-3 and the first cylinder bottom 1-1 and the cylinder head 1-2, a dust ring is provided at the inner ring groove of the cylinder head 1-4 and fits with the middle piston rod 1-12, a sealing ring is provided at the inner ring groove of the guide sleeve 1-5, a guide ring and a sealing ring are provided at the side ring groove of the first piston 1-13, and a sliding sealing ring is provided in the inner ring groove of the hollow piston rod 1-12 and fits with the middle oil pipe 1-9.

[0060] As a preferred embodiment of the present invention, the connection forms of the first oil port 1-6, the second oil port 1-7, the third oil port 1-8, the fourth oil port 1-15 and the fifth oil port 4-1 include threaded connection, flange connection, plate connection, stacking connection and plug-in connection.

[0061] As a preferred embodiment of the present invention, the outer ends of the oil ports of the first oil port 1-6, the second oil port 1-7, the third oil port 1-8, the fourth oil port 1-15 and the fifth oil port 4-1 are provided with hydraulic reversing valves or solenoid valves, and the first oil port 1-6, the second oil port 1-7, the third oil port 1-8, the fourth oil port 1-15 and the fifth oil port 4-1 can all be connected to the oil tank, and hydraulic oil can be introduced into the hydraulic actuator from the outside of the hollow piston rod hydraulic cylinder 1 through the central oil pipe 1-9 and the internal cavity of the hollow piston rod 1-12.

[0062] When the hydraulic pump supplies oil, hydraulic oil flows from the oil tank through the hydraulic pump into the central oil passage of the hollow piston rod hydraulic cylinder 1, then continues through the connecting oil passage 2 to the single-acting hydraulic cylinder 4, pushing up the second piston 4-2 of the single-acting hydraulic cylinder 4, causing it to retract inward, compressing the spring and retracting the locking head. The single-acting hydraulic cylinder 4, acting as a hydraulic actuator, responds to the unlocking action. When the central oil passage is connected to the oil tank, the hydraulic oil flows back to the tank, causing the spring to return to its original length, pushing the second piston 4-2 outward, popping out the locking head, and the single-acting hydraulic cylinder 4, acting as a hydraulic actuator, responds to the locking action.

[0063] When oil is passed into the first rodless chamber 7-6 of the first single-rod hydraulic cylinder and the second rodless chamber 7-12 of the second single-rod hydraulic cylinder, the first piston rod 7-1 and the second piston rod 7-8 are pushed outward, thereby pushing the left arm movable pulley trolley 6 and the right arm movable pulley trolley 3 to move to the sides, and then driving the left grabbing robot arm 10 and the right grabbing robot arm 11 to move to the sides through the second chain pulley transmission mechanism 13 and the first chain pulley transmission mechanism 5. Since the left end of the fixed-length rod 9 is connected to the left arm movable pulley trolley 6, the left arm movable pulley trolley 6 will drive the fixed-length rod 9 to move to the left. When the distance between the left grabbing robot arm 10 and the right grabbing robot arm 11 is about to reach the length of the object to be grasped, the hydraulic oil is stopped from being passed into the central oil circuit of the hollow piston rod hydraulic cylinder 1, and the single-acting hydraulic cylinder 4, under the action of the spring, pops out the lock head so that it fits into the locking groove. At this time, one end of the fixed-length rod 9 is fixed to the left-arm movable pulley trolley 6, and the other end is locked by the single-acting hydraulic cylinder 4 of the right-arm movable pulley trolley 3, thereby realizing the locking function of the fixed-length rod 9.

[0064] The fixed-length rod 9 is locked, and the lengths of both ends of the rod are fixed, forming a fixed-length rod. When the length of the fixed-length rod 9 is fixed, due to the mechanical connection between the left-arm movable pulley trolley 6, the right-arm movable pulley trolley 3, the fixed-length rod 9, the first chain pulley transmission mechanism 5, the second chain pulley transmission mechanism 13, and the left grabbing robot arm 10 and the right grabbing robot arm 11, the distance between the left grabbing robot arm 10 and the right grabbing robot arm 11 is also fixed, and the fixed-length object can be grasped and the locking function is completed.

[0065] like Figure 3 As shown, the main oil circuit connection mode of the present invention is:

[0066] 1) Telescopic oil circuit: After the hydraulic oil is passed through the first oil port 1-6 on the first cylinder bottom 1-1 of the hollow piston rod hydraulic cylinder 1, the hydraulic oil flows into the first oil chamber 1-10; after the hydraulic oil is passed through the third oil port 1-8 on the cylinder head 1-2 of the hollow piston rod hydraulic cylinder 1, the hydraulic oil flows into the second oil chamber 1-11.

[0067] 2) Control oil circuit: After the hydraulic oil is passed through the second oil port 1-7 on the central oil pipe 1-9, the hydraulic oil flows through the central oil pipe 1-9, flows into the cavity of the hollow piston rod 1-12, and then passes through the fourth oil port 1-15 of the hollow piston rod 1-12, passes through the connecting oil circuit 2, and then flows into the rod cavity of the single-acting hydraulic cylinder 4 through the fifth oil port 4-1 on the single-acting hydraulic cylinder 4.

[0068] The first and third oil ports 1-6, 1-8, sixth and seventh oil ports 7-3, 7-4, and eighth and ninth oil ports 7-10, 7-11 are respectively connected to three three-position, four-way hydraulic directional control valves. Each three-position, four-way hydraulic directional control valve is controlled by two two-position, four-way solenoid valves. The second oil port 1-7 is controlled by a single solenoid valve. The accumulator is connected to all oil ports on the bidirectional, single-rod hydraulic cylinder assembly 7, controlling the rapid reciprocating motion of the first and second piston rods 7-1, 7-8, achieving the required rapid traverse speeds for grasping the left and right grabbing arms 10, 11.

[0069] The working principle of the telescopic oil circuit of the present invention:

[0070] When the hydraulic pump supplies oil to the first rodless chamber 7-6 of the bidirectional single-rod hydraulic cylinder assembly 7, the hydraulic oil enters the first rodless chamber 7-6 from the seventh oil port 7-4, pushing the third piston 7-2 outward and the first piston rod 7-1 outward, thereby pushing the left arm movable pulley trolley 6 to the left. This in turn drives the left grabbing robot 10 to the left through the second chain pulley transmission mechanism 13 until the desired distance is reached. Simultaneously, the hydraulic oil in the first rod chamber 7-5 is squeezed and flows back to the oil tank through the sixth oil port 7-3. When the hydraulic pump supplies oil to the first rod chamber 7-5 of the bidirectional single-rod hydraulic cylinder assembly 7, the hydraulic oil enters the first rod chamber 7-5 from the sixth oil port 7-3, pushing the third piston 7-2 inward and the first piston rod 7-1 inward. This in turn pushes the left arm movable pulley trolley 6 to the right. This in turn drives the left grabbing robot 10 to the left through the second chain pulley transmission mechanism 13 until the desired distance is reached. At the same time, the hydraulic oil in the first rodless chamber 7-6 is squeezed and flows back to the tank through the seventh oil port 7-4. By controlling the extension and retraction of the first piston rod 7-1, the reciprocating motion of the left-arm movable pulley 6 can be controlled. Since the left end of the fixed-length rod 9 is connected to the left-arm movable pulley 6, the left-arm movable pulley 6 drives the fixed-length rod 9 to move left and right along the guide device 8.

[0071] Similarly, the hydraulic oil flows from the first oil port 1-6 on the first cylinder bottom 1-1 of the hollow piston rod hydraulic cylinder 1 into the first oil chamber 1-10, lifting the first piston 1-13 and pushing the hollow piston rod 1-12 to move outward, thereby pushing the right arm movable pulley trolley 3 connected to it to move to the right, and then drives the right grabbing mechanical arm 11 to move to the right through the first chain pulley transmission mechanism 5 until it reaches the required distance. The hydraulic oil in the second oil chamber 1-11 is squeezed out from the cylinder head of the hollow piston rod hydraulic cylinder 1 When hydraulic oil flows from the third oil port 1-8 of the hollow piston rod hydraulic cylinder 1-2 into the second oil chamber 1-11, it lifts the first piston 1-13 of the hollow piston rod 1-12. The first piston 1-13 retracts inward, driving the hollow piston rod 1-12 inward, pulling the right arm movable pulley trolley 3 connected to it to the left. This then drives the right grabbing robot 11 to the left through the chain pulley transmission mechanism 5 until the desired distance is reached. At the same time, the hydraulic oil in the first oil chamber 1-10 is squeezed out of the first oil port 1-6 installed in the first cylinder bottom 1-1 of the hollow piston rod hydraulic cylinder 1 and flows back into the oil tank. By controlling the extension and retraction of the hollow piston rod 1-12, the reciprocating motion of the right arm movable pulley trolley 3 can be controlled.

[0072] When fast operation is required, the hydraulic pump pressurizes the accumulator, and the hydraulic oil quickly enters the second rodless chamber 7-12 from the eighth oil port 7-10 on the bottom 7-7 of the second cylinder of the two-way single-rod hydraulic cylinder group 7, lifts the fourth piston 7-9, and pushes the second piston rod 7-8 to move outward, thereby pushing the right arm movable pulley trolley 3 connected to it to move quickly to the right, and then drives the right grabbing mechanical arm 11 to move quickly to the right through the first chain pulley transmission mechanism 5 until it reaches the required distance, and the hydraulic oil in the second rod chamber 7-13 is squeezed out from the first chain pulley transmission mechanism 5. Oil from the ninth oil port 7-11 flows back to the oil tank. Conversely, the hydraulic pump pressurizes the accumulator, and hydraulic oil rapidly enters the second rod chamber 7-13 through the ninth oil port 7-11, lifting the fourth piston 7-9 and driving the second piston rod 7-8 inward. This in turn pushes the right arm movable pulley trolley 3 connected to it to move rapidly to the left. This then drives the right grabbing robot 11 to move rapidly to the left through the first chain pulley transmission mechanism 5 until the required distance is reached. The hydraulic oil in the second rodless chamber 7-12 is squeezed and flows back to the oil tank through the eighth oil port 7-10. The accumulator controls the flow rate of the hydraulic oil, thereby achieving the required rapid reciprocating speed of the grabbing robot.

[0073] The working principle of the oil circuit control of the present invention is as follows:

[0074] After the hydraulic oil is passed to the second oil port 1-7 of the hollow piston rod hydraulic cylinder 1, the hydraulic oil flows through the middle oil pipe 1-9, enters the cavity of the hollow piston rod 1-12, enters the connecting oil circuit 2 through the fourth oil port 1-15 on the end face of the hollow piston rod 1-12, and then flows into the rod cavity of the single-acting hydraulic cylinder 4 through the fifth oil port 4-1, lifting the second piston 4-2 of the single-acting hydraulic cylinder 4, compressing the cylinder bottom spring, retracting the lock head, and completing the unlocking action; when the distance between the left grabbing robot arm 10 and the right grabbing robot arm 11 is about to reach the length of the grasped object, stop feeding the hollow piston rod Hydraulic oil is introduced into the central oil circuit of the hydraulic cylinder 1, and the second oil port 1-7 is connected to the oil tank. The hydraulic oil flows into the connecting oil circuit 2 through the fifth oil port 4-1 of the single-acting hydraulic cylinder 4, and then flows into the cavity of the hollow piston rod 1-12 through the fourth oil port 1-15 on the end face of the hollow piston rod 1-12. Then the hydraulic oil enters the central oil pipe 1-9 and flows back to the oil tank through the second oil port 1-7. The spring returns to its original length, and the second piston 4-2 of the single-acting hydraulic cylinder 4 moves outward under the action of the spring, pops out the lock head, and the lock head cooperates with the locking groove of the fixed-length rod 9 to complete the locking action.

[0075] The hollow piston rod hydraulic cylinder's central oil circuit, as the main component of the control oil circuit, allows the mobile carrier to be connected to an external oil source when there is no external oil pipe, simplifying the hydraulic system structure on the carrier, reducing the weight of the hydraulic system and improving the system controllability. This achieves the purpose of controlling the ejection and retraction of the single-acting hydraulic cylinder lock. Guide devices are installed on both sides of the fixed-length rod, forming a sliding pair with the fixed-length rod. During the reciprocating motion of the fixed-length rod, they provide guidance and support, preventing instability caused by changes in the direction and speed of movement. The locking / unlocking function is achieved by the interaction of the groove on the right end of the fixed-length rod and the single-acting hydraulic cylinder lock, which is easy to control and has a fast response. Due to the mechanical locking structure, the locking is relatively stable and reliable. By matching the lock head with grooves at different positions on the fixed-length rod, the fixed distance between the left and right grabbing arms can be changed to achieve the purpose of grabbing objects of different sizes. By using a hollow piston rod hydraulic cylinder and a bidirectional single-rod hydraulic cylinder group in parallel, the different requirements for the reciprocating speed and running distance of the movable pulley trolley on the left and right sides can be met.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art may adjust the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Therefore, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A double-arm grasping mechanism with a fixed-length locking function, characterized in that: The invention comprises a hollow piston rod hydraulic cylinder (1), a connecting oil circuit (2), a right arm movable pulley trolley (3), a single-acting hydraulic cylinder (4), a first chain pulley transmission mechanism (5), a left arm movable pulley trolley (6), a bidirectional single-rod hydraulic cylinder group (7), a guide device (8), a fixed-length rod (9), a left grabbing mechanical arm (10), a right grabbing mechanical arm (11), a body shell (12) and a second chain pulley transmission mechanism (13), wherein the body shell (12) is provided with a hollow piston rod hydraulic cylinder (1), a connecting oil circuit (2), a right arm movable pulley trolley (3), a single-acting hydraulic cylinder (4), a first chain pulley transmission mechanism (5), a left arm movable pulley trolley (6), a bidirectional single-rod hydraulic cylinder group (7), a guide device (8), a fixed-length rod (9), a left grabbing mechanical arm (10), a right grabbing mechanical arm (11), a body shell (12) and a second chain pulley transmission mechanism (13). An oil circuit (2), a right arm movable pulley trolley (3), a single-acting hydraulic cylinder (4), a first chain pulley transmission mechanism (5), a left arm movable pulley trolley (6), a two-way single-rod hydraulic cylinder group (7), a guide device (8), a fixed-length rod (9) and a second chain pulley transmission mechanism (13); the upper parts of the left grabbing mechanical arm (10) and the right grabbing mechanical arm (11) are arranged inside the machine body shell (12), and the lower parts of the left grabbing mechanical arm (10) and the right grabbing mechanical arm (11) extend out of the machine body shell (12); The hollow piston rod hydraulic cylinder (1) and the two-way single-rod hydraulic cylinder group (7) are connected in parallel, and the hollow piston rod hydraulic cylinder (1) and the two-way single-rod hydraulic cylinder group (7) are both connected to one side of the right arm movable pulley trolley (3), and the other side of the right arm movable pulley trolley (3) is connected to the right grabbing mechanical arm (11) through a first chain pulley transmission mechanism (5), the fixed length rod (9) is arranged at the lower end of the two-way single-rod hydraulic cylinder group (7), and the guide device (8) is sleeved on the outside of the fixed length rod (9), and the left ends of the two-way single-rod hydraulic cylinder group (7) and the fixed length rod (9) are both connected to one side of the left arm movable pulley trolley (6), and the other side of the left arm movable pulley trolley (6) is connected to the left grabbing mechanical arm (10) through a second chain pulley transmission mechanism (13); A single-acting hydraulic cylinder (4) serving as a hydraulic actuator is provided inside the right arm movable pulley trolley (3). A hole is provided in the right arm movable pulley trolley (3) in the direction of piston movement of the single-acting hydraulic cylinder (4). The single-acting hydraulic cylinder (4) can extend outside the right arm movable pulley trolley (3) when the locking head is extended. The single-acting hydraulic cylinder (4) is connected to the hollow piston rod hydraulic cylinder (1) through the connecting oil circuit (2) inside the right arm movable pulley trolley (3). A locking groove is provided on the right end of the fixed-length rod (9), and the locking groove can cooperate with the locking head of the single-acting hydraulic cylinder (4) for locking.

2. A double-arm grabbing mechanism with a fixed-length locking function according to claim 1, characterized in that: The hollow piston rod hydraulic cylinder (1) comprises a first cylinder bottom (1-1), a cylinder head (1-2), a cylinder barrel (1-3), a cylinder cover (1-4), a guide sleeve (1-5), a central oil pipe (1-9) and a hollow piston rod (1-12); the first cylinder bottom (1-1) is arranged on one side of the hollow piston rod hydraulic cylinder (1), the cylinder head (1-2) is arranged on the other side of the hollow piston rod hydraulic cylinder (1), and the first cylinder bottom (1-1) and the cylinder head ( 1-2) are connected by a plurality of pull rods, one end of the cylinder barrel (1-3) is connected to the first cylinder bottom (1-1), the other end of the cylinder barrel (1-3) is connected to the cylinder head (1-2), the hollow piston rod (1-12) is arranged inside the cylinder barrel (1-3), the cylinder cover (1-4) is fixed to the cylinder head (1-2) by countersunk screws, and the guide sleeve (1-5) is arranged between the cylinder head (1-2) and the hollow piston rod (1-12); A first opening is provided at the center of the first cylinder bottom (1-1), and a second opening is provided at the center of the cylinder head (1-2); one end of the through oil pipe (1-9) is connected to the first opening, and the other end of the through oil pipe (1-9) is flush with the end surface of the second opening; the through oil pipe (1-9) passes through the hollow piston rod (1-12) along the axial center line of the hollow piston rod hydraulic cylinder (1) and the hollow piston rod (1-12); and the aperture of the second opening is equal to the outer diameter of the hollow piston rod (1-12).

3. The double-arm grasping mechanism with fixed-length locking function according to claim 2, characterized in that: The hollow piston rod (1-12) comprises a first piston (1-13) and a sealing device (1-14); the first piston (1-13) is threadedly connected or welded to one end of the hollow piston rod (1-12); the first piston (1-13) is slidably arranged inside the cylinder (1-3); the first piston (1-13) divides the cylinder (1-3) into a first oil chamber (1-10) and a second oil chamber (1-11); and the sealing device (1-14) is arranged at the end of the first piston (1-13); The first cylinder bottom (1-1) is provided with a first oil port (1-6), which is connected to the first oil chamber (1-10) and the outside world. The through oil pipe (1-9) is provided with a second oil port (1-7) connected to the outside world at one end close to the first cylinder bottom (1-1). The through oil pipe (1-9) and the internal cavity of the hollow piston rod (1-12) form a through oil circuit structure. The cylinder head (1-2) is provided with a third oil port (1-8), which is connected to the second oil chamber (1-11) and the outside world. The other end of the hollow piston rod (1-12) is provided with a fourth oil port (1-15). The hollow piston rod (1-12) is connected to one side of the right arm movable pulley trolley (3).

4. The double-arm grasping mechanism with fixed-length locking function according to claim 3, characterized in that: The bidirectional single-rod hydraulic cylinder group (7) comprises a first single-rod hydraulic cylinder and a second single-rod hydraulic cylinder which share a second cylinder bottom (7-7), wherein the second cylinder bottom (7-7) is connected in parallel with the first cylinder bottom (1-1); The first single-rod hydraulic cylinder comprises a first piston rod (7-1) and a third piston (7-2). One end of the first piston rod (7-1) extends out of the first single-rod hydraulic cylinder to the outside, and the other end of the first piston rod (7-1) is arranged inside the first single-rod hydraulic cylinder. The other end of the first piston rod (7-1) is connected to the third piston (7-2) by threaded connection or welding. The third piston (7-2) divides the internal cavity of the first single-rod hydraulic cylinder into a first rod cavity (7-5) and a first rodless cavity (7-6). A sixth oil port (7-3) communicating with the first rod cavity (7-5) and the outside is provided on the cylinder head of the first single-rod hydraulic cylinder. A seventh oil port (7-4) communicating with the first rodless cavity (7-6) and the outside is provided on one end of the second cylinder bottom (7-7). The first piston rod (7-1) is connected to one side of the left arm movable pulley trolley (6). The second single-rod hydraulic cylinder includes a second piston rod (7-8) and a fourth piston (7-9), one end of the second piston rod (7-8) extends out of the second single-rod hydraulic cylinder to the outside, the other end of the second piston rod (7-8) is arranged inside the second single-rod hydraulic cylinder, the other end of the second piston rod (7-8) is connected to the fourth piston (7-9) by threaded connection or welding, the fourth piston (7-9) divides the internal cavity of the second single-rod hydraulic cylinder into a second rodless cavity (7-12) and a second rod cavity (7-13), the cylinder head of the second single-rod hydraulic cylinder is provided with a ninth oil port (7-11) communicating with the second rod cavity (7-13) and the outside, the other end of the second cylinder bottom (7-7) is provided with an eighth oil port (7-10) communicating with the second rodless cavity (7-12) and the outside, and the second piston rod (7-8) is connected to one side of the right arm movable pulley trolley (3).

5. The double-arm grasping mechanism with fixed-length locking function according to claim 4, characterized in that: The base of the single-acting hydraulic cylinder (4) is fixed in a mounting groove on the right arm movable pulley trolley (3) by bolt connection. A single output rod matching with the single-acting hydraulic cylinder (4) is installed inside the single-acting hydraulic cylinder (4). A second piston (4-2) is connected to the single output rod by threaded connection or welding. A spring is provided on the top of the second piston (4-2), and the spring is connected to the top of the inner cavity of the single-acting hydraulic cylinder (4).

6. The double-arm grasping mechanism with fixed-length locking function according to claim 5, characterized in that: The single-acting hydraulic cylinder (4) is provided with a fifth oil port (4-1), and the fifth oil port (4-1) of the single-acting hydraulic cylinder (4) is connected to the fourth oil port (1-15) of the hollow piston rod (1-12) via a connecting oil circuit (2).

7. The double-arm grasping mechanism with fixed-length locking function according to claim 6, characterized in that: One end of the cylinder head (1-2) is evenly provided with a plurality of threaded holes, one end of a plurality of pull rods is connected to the cylinder head (1-2) via threads, and the other end of the plurality of pull rods is connected to the first cylinder bottom (1-1) via a plurality of nuts.

8. The double-arm grasping mechanism with fixed-length locking function according to claim 7, characterized in that: A sealing ring is provided at the connection between the cylinder barrel (1-3), the first cylinder bottom (1-1) and the cylinder head (1-2); a dust ring is provided at the inner ring groove of the cylinder cover (1-4) and is in contact with the central piston rod (1-12); a sealing ring is provided at the inner ring groove of the guide sleeve (1-5); a guide ring and a sealing ring are provided at the side ring groove of the first piston (1-13); and a sliding sealing ring is provided in the inner ring groove of the hollow piston rod (1-12) and is in contact with the central oil pipe (1-9).

9. The double-arm grasping mechanism with fixed-length locking function according to claim 8, characterized in that: The connection forms of the first oil port (1-6), the second oil port (1-7), the third oil port (1-8), the fourth oil port (1-15) and the fifth oil port (4-1) include threaded connection, flange connection, plate connection, stacking connection and plug-in connection.

10. The double-arm grasping mechanism with fixed-length locking function according to claim 9, characterized in that: The outer ends of the oil ports of the first oil port (1-6), the second oil port (1-7), the third oil port (1-8), the fourth oil port (1-15) and the fifth oil port (4-1) are provided with hydraulic reversing valves or solenoid valves, and the first oil port (1-6), the second oil port (1-7), the third oil port (1-8), the fourth oil port (1-15) and the fifth oil port (4-1) can all be connected to an oil tank.

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