FOUP taking and placing device used during FOUP automatic storage bin failure

Abstract

The utility model relates to the technical field of taking and placing equipment, in particular to an FOUP taking and placing device used when an FOUP automatic storage bin breaks down. The ladder is arranged on one side of a base of an electric taking and placing device in the FOUP automatic storage bin, the lifting hanging device is detachably arranged on a cross rod of the ladder, the handheld FOUP clamping device is arranged on a lifting rope of the lifting hanging device, and the top end of the ladder is connected with a sky rail of the FOUP automatic storage bin in a sliding mode. According to the utility model, an operator can stand on the ladder to take out and hang down FOUP stored in the FOUP automatic storage bin in a power failure or fault state or hang up the FOUP and place the FOUP in the FOUP automatic storage bin in the power failure or fault state through the cooperation of the lifting hanging device and the handheld FOUP clamping device, so that the efficiency of taking and placing the FOUP is greatly improved; and the safety of taking and placing the FOUP by an operator is improved.

Description

Technical Field

[0001] This utility model relates to the field of retrieval and placement equipment technology, and in particular to a FOUP retrieval and placement device for FOUP automatic storage bins in case of malfunction. Background Technology

[0002] FOUP (Front Opening Unified Pod) is a standard container used to carry and protect wafers, widely used in semiconductor manufacturing plants. An automated FOUP storage bin is a device used to automate the storage and management of FOUPs during semiconductor manufacturing. FOUPs automatically retrieve and place FOUPs onto storage racks via an electrically operated pick-and-place device, as seen in existing Chinese patents with application numbers 202322326130.1, 202310605406.1, and 202310605406.1. However, when the automated FOUP storage bin is in a power outage or malfunction, the electrically operated pick-and-place device cannot retrieve or place FOUPs, requiring manual retrieval from the storage racks. This manual retrieval involves operators repeatedly climbing ladders, resulting in low efficiency and high labor intensity for operators, increasing the risk of accidents due to factors such as accidental disconnection. Therefore, the defects are very obvious, and a solution is urgently needed. Utility Model Content

[0003] In order to solve the above-mentioned technical problems, the purpose of this utility model is to provide a device for taking out and putting in FOUP when the FOUP automatic storage bin fails.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A FOUP retrieval and placement device for FOUP automatic storage bins in case of malfunction includes a ladder on one side of the base of an electric retrieval and placement device installed inside the FOUP automatic storage bin, a lifting and hanging device detachably installed on the crossbar of the ladder, and a handheld FOUP clamping device with a hanging rope installed on the lifting and hanging device. The top of the ladder is slidably connected to the top rail of the FOUP automatic storage bin.

[0006] Furthermore, the handheld FOUP clamping device includes a base, a lifting ring mounted on the top surface of the base, two L-shaped trays mounted opposite each other on both sides of the base, a handle mounted on one side of the base and / or one side of one of the L-shaped trays, and two elastic stop mechanisms mounted on both ends of the base respectively; the lifting rope of the lifting and hanging device is connected to the lifting ring, a slot is formed between the bottom surface of the base and the L-shaped tray, and the two elastic stop mechanisms are located at both ends of the slot; a stop clamping space is formed between the two elastic stop mechanisms, and the stop clamping space is used to accommodate the top plate of the FOUP.

[0007] Furthermore, the elastic stop mechanism includes a linkage rod and two elastic stop components respectively corresponding to the two slots; the elastic stop component includes a mounting base installed on the base body, a stop block telescopically slidably connected to the mounting base, and an elastic element disposed in the mounting base and elastically connected between the mounting base and the stop block. The two ends of the linkage rod are respectively fixedly connected to the stop block of the elastic stop component. The stop block can retract into the mounting base or extend out of the bottom surface of the mounting base. When the stop block retracts into the mounting base, the stop block moves away from the slot; when the stop block extends out of the bottom surface of the mounting base, the stop block extends into the slot.

[0008] Furthermore, an extrusion ramp is provided on the outer side of the bottom end of the stop block.

[0009] Furthermore, the bottom surface of the mounting base is recessed to form a telescopic cavity, the stop block is telescopically slidably connected to the inner wall of the telescopic cavity, and the elastic element is located inside the telescopic cavity.

[0010] Furthermore, the side wall of the mounting base is provided with a lifting groove that communicates with the telescopic cavity, and the end of the linkage rod passes through the lifting groove and is fixedly connected to the side of the stop block.

[0011] Furthermore, the L-shaped tray is provided with a guide slope at its end, which is located on the bottom wall of the end of the slot, and the guide slope and the extrusion slope are in a funnel shape.

[0012] Furthermore, the lifting and hanging device includes a bracket, a locking mechanism disposed on the bracket and detachably connected to the crossbar of the ladder, a cantilever rod vertically disposed on the top of the bracket, and a lifting self-locking pulley installed on the cantilever rod, wherein the suspension rope of the lifting self-locking pulley is connected to the top of the handheld FOUP clamping device.

[0013] Furthermore, the lifting and hoisting device also includes a locking structure installed on the top of the support, which is used to lock the cantilever rod.

[0014] Furthermore, the locking mechanism includes at least one locking component, which includes a lifting plate that is slidably connected to the bracket, a locking member for locking the lifting plate and the bracket together, a U-shaped socket installed on the lifting plate, a locking plate that is translatably installed in the U-shaped socket, and a locking bolt that is threaded through one side wall of the U-shaped socket and abuts against the locking plate.

[0015] The beneficial effects of this utility model are as follows: In practical applications, when the FOUP automated storage bin experiences a power outage or malfunction, the electric pick-and-place device inside the FOUP automated storage bin cannot retrieve the FOUPs stored on the storage rack. In this case, the operator can push the electric pick-and-place device, along with the ladder, along the overhead track to the desired position. Then, one operator climbs the ladder and installs the lifting and slinging device on the ladder. This operator holds a handheld FOUP clamp and uses it to clamp the top plate of the FOUP, removing the FOUP from the storage rack. The lifting and slinging device then lowers the handheld FOUP clamp along with the FOUP. Another operator catches the lowered FOUP and releases the handheld FOUP clamp. The lifting and slinging device then lifts the handheld FOUP clamp again until the operator on the ladder uses the handheld FOUP clamp to retrieve another FOUP. This process is repeated to achieve the goal of lowering the FOUPs stored on the storage rack of the FOUP automated storage bin from top to bottom. This invention enables operators to stand on a ladder and use a lifting and hanging device and a handheld FOUP clamping device to retrieve and lower FOUPs stored in an automated FOUP storage bin that is in a power outage or malfunctioning state, or to lift FOUPs and place them in the automated FOUP storage bin that is in a power outage or malfunctioning state. This greatly improves the efficiency of retrieving and placing FOUPs and enhances the safety of operators when retrieving and placing FOUPs. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the present invention in use; wherein, the FOUP automatic storage compartment conceals the electric loading and unloading device.

[0017] Figure 2 This is a three-dimensional structural diagram of the handheld FOUP clamping device of this utility model for clamping FOUP.

[0018] Figure 3 This is a three-dimensional structural diagram of the FOUP clamping device of this utility model.

[0019] Figure 4 This is a cross-sectional view of the elastic stop component of this utility model.

[0020] Figure 5 This is a three-dimensional structural diagram of the lifting and hanging device of this utility model.

[0021] Figure 6 This is a three-dimensional structural diagram of the locking component of this utility model.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Ladder; 2. Lifting and hanging device; 3. Handheld FOUP clamping device; 4. FOUP automatic storage compartment; 5. Base; 6. Lifting ring; 7. L-shaped support plate; 8. Handle; 9. Elastic stop mechanism; 10. Slot; 11. Linkage rod; 12. Elastic stop assembly; 13. Mounting base; 14. Stop block; 15. Elastic element; 16. Extrusion ramp; 17. Guide ramp; 18. Telescopic cavity; 20. Bracket; 21. Locking mechanism; 22. Cantilever rod; 23. Lifting self-locking pulley; 24. Locking structure; 25. Locking assembly; 26. Lifting plate; 27. Locking element; 28. U-shaped socket; 29. ​​Locking plate; 30. Locking bolt; 31. Observation hole. Detailed Implementation

[0024] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0025] like Figures 1 to 6 As shown, the present invention provides a FOUP automatic storage bin retrieval and placement device for when the FOUP automatic storage bin malfunctions. It includes a ladder 1 installed on one side of the base of the electric retrieval and placement device installed in the FOUP automatic storage bin 4, a lifting and hanging device 2 detachably installed on the crossbar of the ladder 1, and a handheld FOUP clamping device 3 with a hanging rope installed on the lifting and hanging device 2. The top of the ladder 1 is slidably connected to the top rail of the FOUP automatic storage bin 4.

[0026] In practical applications, when the FOUP automated storage and retrieval unit 4 experiences a power outage or malfunction, the electric retrieval device inside the FOUP automated storage and retrieval unit 4 cannot retrieve the FOUPs stored in the storage racks. In this case, the operator can push the electric retrieval device, along with ladder 1, along the overhead track to the desired position. Then, an operator climbs ladder 1 and installs the lifting and hoisting device 2 on ladder 1. The operator then uses a handheld FOUP clamping device 3 to clamp the top plate of the FOUP and retrieve the FOUP. The FOUP is removed from the storage rack, and then the handheld FOUP clamping device 3 is lowered down along with the FOUP using the lifting and hanging device 2. Another operator catches the lowered FOUP and releases the handheld FOUP clamping device 3. Then, the lifting and hanging device 2 lifts the handheld FOUP clamping device 3 up again until the operator on ladder 1 uses the handheld FOUP clamping device 3 to grab another FOUP. This process is repeated to lower the FOUPs stored in the storage rack of the FOUP automated storage bin 4 from top to bottom. This invention enables operators to stand on ladder 1 and use the lifting and hanging device 2 and the handheld FOUP clamping device 3 to retrieve and lower FOUPs stored in the FOUP automated storage bin 4 when it is in a power outage or malfunction, or to lift FOUPs and place them inside the FOUP automated storage bin 4 when it is in a power outage or malfunction, greatly improving the efficiency of FOUP retrieval and placement and enhancing the safety of operators.

[0027] In this embodiment, the handheld FOUP clamping device 3 includes a base 5, a lifting ring 6 mounted on the top surface of the base 5, two L-shaped support plates 7 mounted opposite each other on both sides of the base 5, a handle 8 mounted on one side of the base 5 and / or one side of one of the L-shaped support plates 7, and two elastic stop mechanisms 9 respectively mounted on both ends of the base 5; the lifting rope of the lifting and hanging device 2 is connected to the lifting ring 6, and a slot 10 is formed between the bottom surface of the base 5 and the L-shaped support plate 7, with the two elastic stop mechanisms 9 located at both ends of the slot 10; a stop clamping space is formed between the two elastic stop mechanisms 9, and the stop clamping space is used to accommodate the top plate of the FOUP.

[0028] In practical applications, the operator holds the handle 8, aligning the two slots 10 with the top plate of the FOUP. Then, the operator drives the handheld FOUP clamping device 3 to insert laterally into the top plate of the FOUP, causing the top plate of the FOUP to press against the elastic stop mechanism 9 at one end. This compresses the elastic stop end of the elastic stop mechanism 9, and the top plate of the FOUP moves along the slot 10 until it moves into the stop clamping space. The top plate of the FOUP no longer presses against the corresponding elastic stop end of the elastic stop mechanism 9. The elastic stop end of the elastic stop mechanism 9 springs back and blocks one end face of the top plate of the FOUP. The elastic stop end of the other elastic stop mechanism 9 blocks the other end face of the top plate of the FOUP, thus clamping the top plate of the FOUP onto the handheld FOUP clamping device 3. The FOUP can then be lifted or lowered by the lifting and hanging device 2. Since both ends of the base 5 are equipped with elastic stop mechanisms 9, the operator can hold the handheld FOUP clamping device 3 and insert it from either side of the elastic stop mechanism 9 to the top plate of the FOUP. This makes it convenient for the operator to use the handheld FOUP clamping device 3 to clamp the FOUP. The handheld FOUP clamping device 3 has good structural symmetry and is easy and efficient to operate.

[0029] In this embodiment, the elastic stop mechanism 9 includes a linkage rod 11 and two elastic stop components 12 respectively corresponding to the two slots 10. The elastic stop component 12 includes a mounting base 13 installed on the base body 5, a stop block 14 slidably connected to the mounting base 13, and an elastic element 15 disposed in the mounting base 13 and elastically connected between the mounting base 13 and the stop block 14. The two ends of the linkage rod 11 are fixedly connected to the stop block 14 of the elastic stop component 12. The stop block 14 can retract into the mounting base 13 or extend out of the bottom surface of the mounting base 13. When the stop block 14 retracts into the mounting base 13, the stop block 14 moves away from the slot 10. When the stop block 14 extends out of the bottom surface of the mounting base 13, the stop block 14 extends into the slot 10. Specifically, the elastic element 15 can be a spring.

[0030] In practical applications, when the handheld FOUP clamping device 3 is inserted into the top plate of the FOUP, the top plate of the FOUP will squeeze the stop block 14 of the elastic stop assembly 12, causing the stop block 14 to retract upward into the mounting base 13 and compress the elastic element 15. When the top plate of the FOUP is completely moved into the stop clamping space, the stop block 14 is not subjected to the squeezing force. Under the action of the elastic force of the elastic element 15, the stop block 14 moves downward and resets, so that the stop block 14 extends into the slot 10. The stop blocks 14 of the two elastic stop assemblies 12 block the two sides of the top plate of the FOUP, so that the handheld FOUP clamping device 3 clamps the FOUP. After the FOUP is lowered or placed in the FOUP automatic storage compartment 4, the operator below holds the FOUP with one hand and applies an upward force to the linkage rod 11 with the other hand. This causes the stop blocks 14 of the two elastic stop components 12 to retract upward into the mounting base 13 and compress the elastic element 15. At this time, the FOUP can be pulled out laterally from the handheld FOUP clamping device 3. After the FOUP is pulled out from the handheld FOUP clamping device 3, the operator releases the force on the linkage rod 11, causing the stop blocks 14 to extend into the slot 10 under the rebound force of the elastic element 15.

[0031] In this embodiment, a pressing slope 16 is provided on the outer side of the bottom end of the stop block 14. With the pressing slope 16 in place, during the lateral movement of the FOUP and the handheld FOUP clamping device 3, the top plate of the FOUP abuts against the pressing slope 16 and applies a pressing force to it. As the top plate of the FOUP moves relative to the stop block 14, the stop block 14 retracts upward into the mounting base 13 and compresses the elastic element 15 until the top plate of the FOUP is completely moved into the stopping clamping space. Only then does the stop block 14 move downward and reset under the restoring force of the elastic element 15.

[0032] In this embodiment, the bottom surface of the mounting base 13 is recessed to form a telescopic cavity 18. The stop block 14 is telescopically slidably connected to the inner wall of the telescopic cavity 18, and the elastic element 15 is located inside the telescopic cavity 18. When the stop block 14 moves telescopically, the telescopic cavity 18 guides the stop block 14, improving the stability of the stop block 14's movement and making the structure of the mounting base 13, the elastic element 15, and the stop block 14 compact.

[0033] In this embodiment, the side wall of the mounting base 13 is provided with a lifting groove that communicates with the telescopic cavity 18. The end of the linkage rod 11 passes through the lifting groove and is fixedly connected to the side of the stop block 14. The lifting groove not only facilitates the connection between the linkage rod 11 and the stop block 14, but also guides the linkage rod 11, improving the stability of the lifting and lowering movement of the linkage rod 11 and limiting the lifting stroke of the linkage rod 11. Furthermore, when the stop block 14 extends into the slot 10 under the elastic force of the elastic member 15, the bottom wall of the lifting groove supports the linkage rod 11.

[0034] Specifically, the side wall of the L-shaped tray 7 is provided with an observation hole 31 that communicates with the slot 10, and the observation hole 31 is correspondingly set with the stop block 14. During use, the operator can observe the usage status of the stop block 14 through the observation hole 31 to ensure that the stop block 14 can work normally.

[0035] In this embodiment, the end of the L-shaped tray 7 is provided with a guide slope 17, which is located on the bottom wall of the end of the slot 10. The guide slope 17 and the extrusion slope 16 are flared to serve as a flare and guide. With this structural design, when the top plate of the FOUP is inserted and clamped by the handheld FOUP clamping device 3, the guide slope 17 and the extrusion slope 16 serve as a guide, making it easier for the top plate of the FOUP to be inserted and clamped by the handheld FOUP clamping device 3.

[0036] In this embodiment, the lifting and hanging device 2 includes a bracket 20, a locking mechanism 21 disposed on the bracket 20 and detachably connected to the crossbar of the ladder 1, a cantilever 22 vertically disposed on the top of the bracket 20, and a lifting self-locking pulley 23 mounted on the cantilever 22. The suspension rope of the lifting self-locking pulley 23 is connected to the top of the handheld FOUP clamping device 3. In practical applications, the bracket 20 is locked to the crossbar of the ladder 1 by the locking mechanism 21 to achieve the assembly of the lifting and hanging device 2 and the ladder 1. When the handheld FOUP clamping device 3 clamps the top plate of the FOUP and removes the FOUP from the FOUP automatic storage compartment 4, the FOUP is lowered by the lifting self-locking pulley 23. Since the locking mechanism 21 is detachably connected to the crossbar of the ladder 1, the height of the lifting self-locking pulley 23 can be changed by installing the locking mechanism 21 on the crossbars of the ladder 1 at different heights.

[0037] Specifically, the support 20 of the lifting and hanging device 2 is equipped with a shoulder strap; in practical applications, the operator wears the shoulder strap to carry the lifting and hanging device 2 on their back, at which point the operator can climb the ladder 1; by carrying the lifting and hanging device 2 on the operator's back, the safety of the operator climbing the ladder 1 is improved, and it is also convenient to install and fix the lifting and hanging device 2 on the crossbar of the ladder 1 at the required height.

[0038] In this embodiment, the lifting and hanging device 2 also includes a locking structure 24 installed on the top of the bracket 20. The locking structure 24 is used to lock the cantilever rod 22. The locking structure 24 facilitates the disassembly, assembly, and maintenance of the cantilever rod 22 and the bracket 20, realizes the modular assembly of the lifting and hanging device 2, and facilitates transportation, carrying, and storage.

[0039] In this embodiment, the locking mechanism 21 includes at least one locking component 25. The locking component 25 includes a lifting plate 26 that is slidably connected to the bracket 20, a locking member 27 for locking the lifting plate 26 and the bracket 20 together, a U-shaped socket 28 installed on the lifting plate 26 with its opening facing downward, a locking plate 29 that is translatably disposed within the U-shaped socket 28, and a locking bolt 30 that is threaded through one side wall of the U-shaped socket 28 and abuts against the locking plate 29. Specifically, the locking component can be a bolt.

[0040] In practical applications, the U-shaped socket 28 is inserted into the crossbar of the ladder 1. The crossbar of the ladder 1 is located between one side wall of the U-shaped socket 28 and the locking plate 29. Then, the locking bolt 30 is tightened so that the locking bolt 30 is screwed into the U-shaped socket 28 and abuts against the locking plate 29, causing the locking plate 29 to move closer to the crossbar of the ladder 1 until the locking plate 29 engages with one side wall of the U-shaped socket 28 and is locked onto the crossbar of the ladder 1. When it is necessary to disassemble the lifting and hanging device 2, simply loosen the locking bolt 30 to remove the U-shaped socket 28 from the crossbar of the ladder 1. In addition, loosening the locking member 27 allows the lifting plate 26 to rise and fall relative to the bracket 20, thereby changing the height position of the locking assembly 25 on the bracket 20, and thus changing the height of the cantilever rod 22 and the lifting self-locking pulley 23.

[0041] Specifically, there are two locking mechanisms 21, which are arranged along the height of the bracket 20. By increasing the number of locking mechanisms 21, the stability of the lifting and hanging device 2 locked to the crossbar of the ladder 1 is improved.

[0042] All technical features in this embodiment can be freely combined according to actual needs.

[0043] The above embodiments are preferred implementations of this utility model. In addition, this utility model can also be implemented in other ways. Any obvious substitutions without departing from the concept of this technical solution are within the protection scope of this utility model.

Claims

1. A FOUP retrieval and placement device in case of FOUP automatic storage compartment failure, characterized in that: The device includes a ladder (1) on one side of the base of an electric retrieval device installed in the FOUP automatic storage compartment (4), a lifting and hanging device (2) detachably installed on the crossbar of the ladder (1), and a handheld FOUP clamping device (3) with a hanging rope installed on the lifting and hanging device (2). The top of the ladder (1) is slidably connected to the top rail of the FOUP automatic storage compartment (4).

2. The FOUP retrieval and placement device for an automated FOUP storage bin in case of malfunction, as described in claim 1, is characterized in that: The handheld FOUP clamping device (3) includes a base (5), a lifting ring (6) installed on the top surface of the base (5), two L-shaped trays (7) installed on opposite sides of the base (5), a handle (8) installed on one side of the base (5) and / or one side of one of the L-shaped trays (7), and two elastic stop mechanisms (9) respectively installed at both ends of the base (5); the lifting rope of the lifting and hanging device (2) is connected to the lifting ring (6), and a slot (10) is formed between the bottom surface of the base (5) and the L-shaped tray (7), and the two elastic stop mechanisms (9) are located at both ends of the slot (10); a stop clamping space is formed between the two elastic stop mechanisms (9), and the stop clamping space is used to accommodate the top plate of the FOUP.

3. The FOUP automatic storage bin retrieval and placement device according to claim 2, characterized in that: The elastic stop mechanism (9) includes a linkage rod (11) and two elastic stop components (12) respectively corresponding to the two slots (10); the elastic stop component (12) includes a mounting base (13) installed on the base body (5), a stop block (14) slidably connected to the mounting base (13) telescopically, and an elastic element (15) disposed in the mounting base (13) and elastically connected between the mounting base (13) and the stop block (14). The two ends of the moving rod (11) are fixedly connected to the stop block (14) of the elastic stop assembly (12). The stop block (14) can retract into the mounting base (13) or extend out of the bottom surface of the mounting base (13). When the stop block (14) retracts into the mounting base (13), the stop block (14) moves away from the slot (10). When the stop block (14) extends out of the bottom surface of the mounting base (13), the stop block (14) extends into the slot (10).

4. The FOUP retrieval and placement device for an automated FOUP storage bin in case of malfunction, as described in claim 3, is characterized in that: The bottom outer side of the stop block (14) is provided with an extrusion slope (16).

5. The FOUP retrieval and placement device for an automated FOUP storage bin in case of malfunction, as described in claim 4, is characterized in that: The mounting base (13) has a downward recessed telescopic cavity (18) on its bottom surface. The stop block (14) is telescopically slidably connected to the inner wall of the telescopic cavity (18), and the elastic element (15) is located inside the telescopic cavity (18).

6. The FOUP retrieval and placement device for an automated FOUP storage bin in case of malfunction, as described in claim 5, is characterized in that: The side wall of the mounting base (13) is provided with a lifting groove that communicates with the telescopic cavity (18). The end of the linkage rod (11) passes through the lifting groove and is fixedly connected to the side of the stop block (14).

7. The FOUP automatic storage bin retrieval and placement device according to claim 4, characterized in that: The L-shaped tray (7) is provided with a guide slope (17) at its end. The guide slope (17) is located on the bottom wall of the end of the slot (10). The guide slope (17) and the extrusion slope (16) are in the shape of a trumpet.

8. The FOUP retrieval and placement device for an automated FOUP storage bin in case of malfunction, as described in claim 1, is characterized in that: The lifting and hanging device (2) includes a bracket (20), a locking mechanism (21) disposed on the bracket (20) and detachably connected to the crossbar of the ladder (1), a cantilever (22) vertically disposed on the top of the bracket (20), and a lifting self-locking pulley (23) installed on the cantilever (22). The suspension rope of the lifting self-locking pulley (23) is connected to the top of the handheld FOUP clamping device (3).

9. The FOUP retrieval and placement device for an automated FOUP storage bin in case of malfunction, as described in claim 8, is characterized in that: The lifting and hoisting device (2) also includes a locking structure (24) installed on the top of the bracket (20), which is used to lock the cantilever rod (22).

10. The FOUP retrieval and placement device for an automated FOUP storage bin in case of malfunction, as described in claim 8, is characterized in that: The locking mechanism (21) includes at least one locking component (25), which includes a lifting plate (26) that is slidably connected to the bracket (20), a locking member (27) for locking the lifting plate (26) and the bracket (20) together, a U-shaped socket (28) installed on the lifting plate (26), a locking plate (29) that is translatably installed in the U-shaped socket (28), and a locking bolt (30) that is threaded through one side wall of the U-shaped socket (28) and abuts against the locking plate (29).

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